ENGAGING STAKEHOLDERS IN CONSTRUCTION AND VALIDATION OF BAYESIAN BELIEF NETWORK FOR GROUNDW
ENGAGING STAKEHOLDERS IN CONSTRUCTION AND VALIDATION OF BAYESIAN BELIEF NETWORK FOR GROUNDWATER PROTECTION
Hans J?rgen Henriksen a , Per Rasmussen a , Gyrite Brandt b , Dorthe von Bülow b and Finn Verner Jensen c
a
Geological Survey of Denmark and Greenland (GEUS), ?ster Voldgade 10,
DK-1350 Copenhagen K, Denmark; b Copenhagen Energy,Vognmagergade 8, Copenhagen K, Denmark
c Aalborg University, Department of Computer Science, DK- 9220 Aalborg
Abstract: A Bayesian belief network (BN) for farming contracts has been constructed and validated with direct co-operation and in dialogue with stakeholders. On the one hand,BN’s can create space for an open dialogue with stakeholders due to the flexibility of the decision support tool. This allows factors (nodes), associations (directed links) and probabilities to be adjusted and validated throughout the process and based on inputs from all involved stakeholders and experts. On the other hand getting stakeholders to understand and accept the idea behind BNs is demanding. Especially the required probability assessments are not easy to understand by stakeholders. Copyright ? 2004IFAC
Keywords: Pesticides, precautionary groundwater protection, bayesian belief networks,stakeholder involvement, voluntary farming contracts
1. INTRODUCTION
Agriculture currently accounts for two-thirds of land use in Denmark, and the farmed area covers some 2,7million ha. More than half of the agricultural area is used to grow cereals, mainly winter cereals. These crops have a high leaching potential, because they need additional fertilisers and pesticides. Pork accounts for about a third of agricultural production value, and diary products have a share of 20 % of total production value. Denmark is one of the leading countries in the world exporting pork. Agriculture is a rather marginal activity, if measured in terms of the share of agriculture of the Gross Domestic Product (GDP, only 2%). However, agriculture remains important economically, having a share of approximately 14 % of national exports (Danmarks Statistik, 2000; Brouwer, 2003).
Copenhagen Energy (CE) is the largest water supply company in Denmark. It daily supplies with drinking water roughly one million inhabitants in the greater
Copenhagen area.
Very vulnerable Vulnerable Less vulnerable Least vulnerable
One or more pesticides above l.o.d., but below MAC No pesticdes above l.o.d.Wellfield catchment area
One or more pesticides above MAC Fig. 1. Havelse wellfield case study area (35 km 2).
CE operates 55 large wellfields with thousands of farmers. The applicability of graphical models (Bayesian networks, BNs) in water resource management regarding groundwater protection has been tried out in a case study comprising one of CE’s wellfields (Havelse) in Northern Zealand, Denmark (Figure 1).
2. THE OBJECTIVES OF THE CASE STUDY We know a great deal about the quality of the deep groundwater in Denmark from work on a national scale (GEUS, 2003). However, we have little knowledge about the quality of the young groundwater and we don’t know exactly to which extend pesticide contaminated shallow groundwater, in the long run affects deep groundwater. The application of pesticides to agricultural fields according to regulative guidelines, accidents, point sources, past mistakes, and the spread of pesticides (e.g. BAM) all contribute to a high frequency of findings both in shallow and deep groundwater, as well as in surface water (Henriksen et al., 2004). Active groundwater protection from pesticides requires innovative solutions (Brandt and Henriksen, 2003), co-ordination of actions by various authorities and commitment to implementation from the different stakeholder groups. Lack of knowledge about different sources of pesticide pollution, vulnerability and spreading of pesticides to drinking water may hamper and threaten existing protection initiatives and undermine the overall efficiency.
In order to identify actions that can be implemented in practice, discussion and dialogue with stakeholders and general public about the factors and consequences are necessary. The traditional approaches taken by CE for groundwater protection are afforestation, establishment of monitoring wells and establishment of local waterworks cooperation forums. Until now farming contracts have only been considered as a possible (novel) future action, not a measure that is a part of CEs current strategy for groundwater protection.
Farming contracts will influence a number of issues. Therefor, an interdisciplinary analysis of the possibilities and problems connected with five or ten year farming contracts, with totally stop of the use of pesticides in return for compensational payment is required. The aim of the case study is to describe in what way the introduction of areas with no pesticide applications may influence farming economics, groundwater quality, biodiversity and the aquatic environment.
The involvement of farmers and other stakeholders is vital for developing novel actions for CEs groundwater protection strategy because the response and behaviour of these groups are critical for the implementation of such novel initiatives.The type of decision support tool chosen for the present case study, Bayesian networks (BNs), have for many years been used routinely in the fields of medicine and artificial intelligence. Until now BNs have only had limited application to environmental problems.
Hence, the specific objectives of the case study can be formulated as follows (Henriksen et al., 2004):
1.To construct a Bayesian belief network (BN)
study site in Denmark with a focus on innovative actions for precautionary groundwater protection against pesticide threats.
2.To investigate the extent to which BNs can be
used as a decision support tool for water resource management at a wellfield abstracting groundwater from the downstream part of a river basin.
3.To develop techniques to encourage and enable
full stakeholder involvement in the construction of BNs. This final but critically important component will provide an evaluation of the most effective means to involve stakeholder groups in the decision-making process.
3. BAYESIAN NETWORK (BN)
A Bayesian belief network (BN), also called a belief network, is a type of decision support system based on probability theory which implements Bayes’ rule of probability (Pearl, 1988; Cowell et al., 1999; Jensen, 2001; Korb and Nicholson, 2004). This rule shows mathematically how existing beliefs can be modified with the input of new evidence. Devised by Thomas Bayes, an eighteenth-century English clergyman, BNs organise the body of knowledge in any given area by mapping out cause-and-effect relationships among key variables and encoding them with numbers that represent the extent to which one variable is likely to affect another.
BNs have become a highly successful technique in medical diagnostic systems, analysis, artificial intelligence, and decision-making in real-world domains. They have been applied for many years in practice in a variety of fields, including engineering, science, and medicine (Andreasen et al., 1989; Abramson, B. and Finizza A, 1991; Jensen et al., 2001; Marcot et al., 2001; Borsuk et al., 2002; Gomez, 2004). BNs have gained a reputation of being powerful techniques for modelling complex problems involving uncertain knowledge and uncertain impacts of causes. They can be used in a way that promotes an improved understanding of the environmental system, leaving decision-makers to reach their own conclusions on the basis of that understanding. Ideally, BNs are a technique to assist decision-making that is especially helpful when there is scarcity and uncertainty in the data used in taking the decision and the factors are highly interlinked, all of which makes the problem highly complex.
BNs can help to formulate environmental management strategies by:
?Allowing users to build their own environmental decision support system (EDSS). By building it themselves, users can ensure that the decision support system meets their needs.
?Helping users to understand the nature of their decisions better. An EDSS should help users make a better decision, not an easier one. It should not make the decision for the user.
Instead, it should encourage the user to identify all the relevant information and analyse it more in depth.
?Encouraging users to deal with uncertainty. It is impossible to be certain about the consequences of any environmental management decision. This fact must be recognised together with the effect of uncertainty of the decision.?Encouraging consultation with stakeholders.
Without stakeholder consultation, it is unlikely that an environmental management decision can be implemented.
The graphical nature of BNs facilitates formal discussion of the structure of proposed model and the ability of a BN to describe the uncertain relationships amongst variables is ideal to describe the relationship between events which may not be well understood.
4. CONSTRUCTION OF BN
The BN construction in the Havelse case study was undertaken in stepwise fashion with the following main steps, with feedback loop from Step 7 to 3:
1.Define the context
2.Identify factors, actions and indicators
3.Build pilot network
4.Collect data
5.Define states
6.Construct conditional probability tables (CPTs)
7.Collect feed back from stakeholders
It was considered from the start of the project, if necessary subsequently to repeat Step 3-7 several times based on the character of the feedback.
In Step 1, physical and socio-economic boundaries, area of interest, alternative scenarios, and indicators are defined. The degree of stakeholder involvement (information, consultation, active involvement or social learning is also determined). Afterwards, at meetings with stakeholders and general public, working groups are set up, stakeholder interests analysed and responsibilities clarified.
In Step 2, a list of stakeholder and general public concerns is drawn up, and actions to be taken and important indicators are defined. A synopsis of data sources, reports, stakeholders and models is described and agreed upon.In Step 3, the important variables are identified, and directed edges are selected and connected. Rules for participation are also described, and the platform for information decided.
In Step 4, the data from different sources (including stakeholders and general public) are collected. Data are analysed and initially a simple BN is prepared as an illustration of what to do in the following steps. After feedback from stakeholders and public in Step 7, BNs are adjusted and refined with additional variables and links.
In Step 5, input from stakeholders and general public is important especially for indicator variables and actions. States are implemented in BNs for all variables.
In Step 6, constructing conditional probability tables (CPTs), includes a review of the networks at individual stakeholder meetings. Parameter learning is encouraged as a method of bridging data and CPTs. Inputs from domain models and experts is also part of this step in order to prepare all required quantitative informations for CPTs. BNs should also be carefully checked for internal consistency at this stage.
In Step 7, stakeholder and general public opinions on the final network are collected, and a conclusion based on the final BN is drawn. Furthermore, it is decided if additional adjustment of BN is required (feedback and carrying out Step 3-7 again). The final BN is documented and implemented in the decision support system (DSS), and used for describing the results of the alternative scenarios, which had been selected.
Information, consultation and active involvement of professional stakeholders and general public was carried out as a necessary part of the BN construction using announcements and facilitated public meeting (Step 1-2), working group meetings (Step 1-3), newsletters, a Web site, individual meetings (Step 4-6) and a joint working group (Step 7). The facilitator of the public meeting and workshops was the Agenda 21 Centre in Frederikssund. Various subcontractors have participated in the project, e.g. farm economics (Rasmussen, 2003) and value of biodiversity, land use, etc. (Schou, 2003).
Consultation by use of questionnaires, joint workshop and draft report send in hearing allowed stakeholders and citizens’ group to give feedback and comments to the constructed BNs and the use of BNs as a decision support system.
5.THE BN MODEL
The general idea with the BN for farming contracts was to analyse the effects of compensation payments to farmers for not using pesticides on agricultural fields. The higher the compensation level, the more
farmers will join such a voluntary contract. However, farmers signing a contract will also try to optimise land use by growing crops more suitable for farming without pesticides, and this means that contracts will also affect crop rotation.
Farming contract restrictions and crop rotation affect the farmers’ bottom line, so to speak, and this, together with the compensation payment, has an impact on farm economics as a whole. All the relationships in this part of the farming contract BN were initially provided by subcontractor Svend Rasmussen from the Royal Veterinarian and Agricultural University (KVL), which also collected the data for pesticide application for different crop rotations (Rasmussen, 2003).
The other part of the final BN in Figure 2 shows variables concerning environmental impacts of pesticide application. These variables were based on information from monitoring programmes at GEUS and CE (GEUS, 2003; Brüsch et al., 2004). Furthermore, research had shown that high concentrations of herbicides in surface water impacts the reproductive capability of leopard frogs (expressed by the variable “biological abnormality”). The types of variables in the BN in Figure 2 can be grouped into five categories:
1.Objectives. Things that are affected: Shallow
groundwater quality, Biological abnormality, Biodiversity, Surface water quality 2, Recreative value and Deep groundwater quality. Overall objective: Safe supply.
2.Interventions. Things which must be
implemented or included in CE policy: Compensation, Non-point application and Remove point sources.
3.Intermediate factors. Variables which link
objective variables with intervention variables: Farming contracts, Land use, Farm economics, Pesticide load, Diffuse, Surface water quality, Point sources and Hunting/fishing.
4.Controlling factors. Factors that control the
environmental system: Sand/clay, Animal/vegetabile, SFL area (vulnerable farming areas). Uncertain controlling factors: Perception of vulnerability (stakeholders do not agree).
5.Decision and utility variables. Variables that are
included in order to calculate and visualise a certain utility: All-farm economy and Utility node.
The decision variable “All farm economy” is simply added to the BN in order to make the total utility for farmers fully transparent (production exclusive fixed costs for machinery etc. – plus compensation payment).
One variable is aimed at directly focusing on overall outcome of BN:
?Safe supply of drinking water, a boolean variable which can be true or false: true means that clean
groundwater will have a content of pesticides below the maximum allowed concentration, for at least 50 years
The most common pesticide found in existing monitoring data is BAM – 2.6 dichlorbenzamide, which is a metabolite of the herbicides dichlobenil or chlorthiamide. BAM is the greatest threat to groundwater quality at the moment (GEUS, 2003; Brüsch et al., 2004). The use of the BAM herbicide is now prohibited.
The pesticide findings were made in a village, and it is probably more point-source pollution than diffuse pollution. Similar vulnerable or very vulnerable areas are also found inside the catchment area and in the present wellfield zone. The vulnerability is here an expression of the thickness of the clay layer above the primary reservoir and whether the aquifers are unconfined or confined.
However new pesticide analyses from five drilled wells, four dug wells and Havelse Creek showed various herbicides (BAM and Mechlorprop) in two dug wells and one drilled well, but also (AMPA a degradation product of Glyphosat) in Havelse creek, all with findings above the MAC value.
6. USE OF BN AS DECISION SUPPORT TOOL Two scenarios were analysed (Henriksen et al., 2004):
1.Farming contracts: voluntary farming contracts
(different compensation level)
2.Both actions: voluntary farming contracts plus
removal of point sources (it is assumed that all point sources are simply removed)
Figure 3 illustrates that the compensation payment must be corresponding to MVJ high level compensation agreement. The Danish acronym MVJ stands for ‘Environmental friendly agricultural agreements’ that beside no pesticide application includes other restrictions e.g. use of fertilisers, choice of vegetation etc. The level of compensation for MVJ is DKK 4400 per ha/year, of this up to 60% financed by the EU.
The only way to achieve the “preventive goal”(minimum a 95% probability for the state “true” of the safe supply) is by the high level compensation of the standardised MVJ agreement. Even if both actions are taken, with an additional cost for removing all the point sources, the result is the same. We have not considered the move of the wellfield away from the Havelse creek in the present analysis. This could both increase the probability of the “safe supply” being in the state of “true”, but other effects could also adversely decrease this probability (intrusion of salt water closer to the Roskilde Fjord bay or unknown point sources close to the new wellfield location).
Fig. 2. Final BN for voluntary farming contracts
For a compensation of DKK 500 per ha/year, few farmers (4 %) would join voluntary farming agreements prescribing no pesticide application. For DKK 1000 per ha/year, a slightly larger fraction would join (11%). At DKK 2500 per ha/year, nearly 50% would join, but their willingness to sign voluntary preventive farming contracts (no pesticides) is much less than the input from the expert indicated (Rasmussen, 2003), which indicated a break-even point of below DKK 1500 per ha/year.
Objectives
Controlling/intermediate factors
20406080100
none
500
1000
1500200025004400level of compensation (kr. per ha)
farming contracts
both actions
50
403020100
Surface water quality Shallow groundwater quality Deep groundwater quality
fc
fc and rps fc
fc and rps fc
fc and rps
fc = farming contracts rps = removal of point sources
Farming contracts and removal of point sources
Water quality indicators (probability > 0,1 ug/l)
safe supply (= true)level of compensation (kr. per ha)
Fig. 3. Comparison of overall indicator (safe supply)for the two alternative scenarios: “Scenario 1:farming contracts” and “Scenario 2: both actions”for different levels of compensation.The main problem is related to a lack of commitment to realistic levels of compensation. Farmers in the area have suggested compensation payment levels of about DKK 5000 per ha/year. Farmers’ organisations (NOLA and Sj?llands Familielandbrug ) have indicated that such agreements should either offer a very high compensation (up to DKK 7000 per ha/year) or not be part of groundwater protection at all (expropriation may be necessary and a more feasible method).
The Scenario 1 indicators for water quality show that the probability of polluted deep groundwater above MAC drops to below 5% at a compensation level of DKK 2500 per ha/year. This probability varies for the different compensation level from 8.3% (none) to 7.3% (500), 7.5% (1000), 6.6% (1500), 5.8% (2000),4.3% (2500) to 1.3% (DKK 44 per ha/year). Scenario 2 reaches the 5% level at DKK 1000 per ha/year,signifying that action directed at point sources (removal) may be a necessary element of groundwater protection policy.
In Scenario 1, shallow groundwater has a probability of pesticide content of between 41.7% (none) and 33.2% (DKK 1500 per ha/year). Not until DKK 4400per ha/year does the probability drop below 10% for clean groundwater (6.6% probability). Scenario 2results in an achieved goal of a 5% level at DKK 4400 per ha/year including removal of point sources. Similar results were found for surface water.
Furthermore, the exercise demonstrated that cost/benefit issues and especially the implementation of management action plans are associated with many more issues than expert knowledge normally takes into consideration.
In our case, a barrier for voluntary farming contracts is not data or information on economic conditions in farming, but, to a much greater extent, perception among stakeholders of the soundness of the action.Attitudes, beliefs and group behaviour (Robbins,2003) among farmers and their organisations, and the uncertainty and lack of data, play a more important role than a possible financial benefit in the short run.Since farming contracts also are rather difficult to manage (Brouwer, 2003), at least as voluntary agreements negotiated within a wellfield catchment area as part of a groundwater protection plan, the entire approach is both costly and difficult to implement.
7. TECHNIQUES TO ENCOURAGE AND ENABLE STAKEHOLDER INVOLVEMENT Havelse wellfield catchment is located in three municipalities: Slangerup, Frederikssund and Frederiksv?rk, all in Frederiksborg County. There are smaller local waterworks within the wellfield catchment area. Frederiksborg County is responsible for water resources planning, and the municipalities are responsible for the water supply. The land use in the area is predominantly conventional agriculture.The Havelse Creek runs through the area; it is used for angling, and the county has plans to re-establish wetlands along the creek. Copenhagen Energy's groundwater abstraction license for Havelse wellfield is due for a renewal in a few years’ time, and the wellfield will have to undergo renovations in the near future (Brandt and Henriksen, 2003).
The starting point for identifying stakeholders was trying to list categories of water users, potential groundwater pollution sources, and authorities in the area: local waterworks, other water consumers,farmers, industry, anglers, the county and the municipalities.
We started off by sending letters to all professional stakeholder organisations that we found to have a potential or even marginal interest in groundwater protection in the specific area inviting them to a one-day workshop in October 2002. Many "green" NGOs did not show up; the industrial sector preferred to use their political contacts on groundwater issues, they told us. One result of this workshop was the formation of a professional stakeholder working group with ten institutions, including the project end user CE, the local Agenda 21 centre (facilitator in relation to citizens’ group), and GEUS (see Figure 6).
The next step was in November 2002: a public meeting in the local community hall. Invitations were distributed to more 1100 local households, and the meeting was announced in the local newspaper. About 100 people and the local TV station showed up for the meeting. At the end of the meeting, a local citizen working group of nine persons had been formed. At both meetings, stakeholders were asked to present issues and problems they found important in relation to groundwater protection.
In the following course of the project the stakeholders were organised into two different groups: the professional stakeholder group, and local citizens stakeholder group. The idea behind the split of stakeholders in two groups was the perception that the professional stakeholders are already deeply involved in groundwater management and protection, whereas local citizens might have another starting point for their involvement in groundwater management and protection (Henriksen et al., 2004).
At meetings and workshops with citizens’ group, we used a facilitator from the local joint municipality Agenda 21 centre. Facilitation in relation to the group of professional stakeholders was not systematic throughout the project, but the first meeting was facilitated by Agenda 21 centre.
The citizen group met five times in the first half of 2003. The idea was to give the group the opportunity to develop its own identity without being influenced by professional stakeholders. The meetings were guided by the facilitator. GEUS and CE only participated in two of the five meetings to answer specific questions and to introduce and discuss the development of the BNs.
The citizen group published two newsletters in the first half-year of 2003. A third newsletter was published in July 2004 after finishing the final MERIT report. They were distributed to 1000 households in the local area. The newsletters included mainly articles related to groundwater protection, water supply and water quality, and introduced the members of the citizen group. The production and distribution of the newsletter was financed by the MERIT project.
At the final joint meeting in March 2004, the stakeholder groups were asked to comment on the in-volvement process on the basis of four questions (Henriksen et al., 2004):
1.Is there a need for further initiatives for the
protection of groundwater and the stream/bay? 2.How have you experienced the MERIT project
progress (BNs, citizens’ meeting, workshops, citizen groups, newsletter, individual meetings, etc.)?
3.How should stakeholders be involved in the
future in, for example, active groundwater protection and the establishment of wetlands? 4.Other comments to the process?Furthermore, comments and suggestions from the stakeholders and citizens’s group to the draft report was collected by consultation (from questionnaires and hearing in May 2004) and consequences for the final reporting addressed.
The overall idea was to begin the process as openly as possible, to get an idea of how stakeholders could contribute to an improved protection of the groundwater resources in the area.
There was a frustration due to a lack of information and time to finalise the work in the working groups, which should give input to BNs, as expressed by the citizens group:
“Next time the project group addresses this subject, they must be more aware of the fact that the citizens' group is often much more interested than expected (and much better qualified – in some areas perhaps even better and more broadly orientated out of interest than the specialists). For this reason, the project group should do better preparatory work with better information; the citizens' group does not wish to be put off with cursory information. And it sounds as though the work has led to somewhat of an understanding of this. It is correct that it is best to include interest groups in the BN model construction phase, but it should be done openly, objectively and from the beginning. Don't keep the citizens' group outside the door because you don't think they understand the topic. Be aware of the fact that the citizens' group is willing to contribute much more volunteer work than you apparently think; you only have to include and engage them. They know that the result of the work will have an impact on their own situation, and the specialists should not forget that many members of the general public are extremely well qualified when it comes to finding information on the Internet. The old specialist world is changing. The citizens' group can understand a BN just fine if it is explained properly by the specialists”.
Conflicts and frustration should rather be handled as necessary and gaining events than something that should be avoided (Robbins, 2003). Frustrations are necessary for finding new and innovative solutions to complex problems.
8. EVALUATION
Even though stakeholders and citizens generally expressed disappointment with participation in the project and in the working groups, including the roles played by GEUS, CE and the Agenda 21 Centre, most stakeholders and citizens also felt that they had had an influence on the development of the BNs. Some remarks were:
?“The project management was open and positive about discussing the elements.”
?“CE and GEUS found out that farming contracts are not an applicable solution.”
?“They listened to suggestions.”
According to stakeholders and citizens, the greatest advantages of the BNs were the following: ?“Used properly, a good, flexible tool for integration”
?“Clear overview”
?“Good tool for dialogue”
?“The citizens' group can understand a BN just fine if it is explained properly by the specialists”. The greatest limitations of BNs:
?“Require insight and understanding”
?“You get the answers you want”
?“Not applicable to groundwater protection”?“Selection of precise data required”?“Correctness of information is questioned”?“A complex tool whose primary strength is as a tool for dialogue”
?“Number of variables must not be too large or overview is lost and relationships less clear”
We experienced both successes and barriers in the case study:
Successes
?Many people showed up at the public meeting.?The citizen group wants to continue beyond the project.
?Increased level of knowledge on both sides of the table.
? A deeper understanding of pesticide sources and precautionary actions.
?Implementation of cooperative farming contracts is not only a question of money.
?There are new opportunities to establish waterworks cooperation projects in the area.?There is now cooperation with selected stakeholders about groundwater protection.Barriers / Problems encountered
?One of the key players in groundwater
management did not go wholeheartedly into the
project (Frederiksborg County).
?NGOs/environmentalists were weakly
represented and had little voice.
?GEUS and CE defended to some extent the role of NGOs/environmentalists.
?The workshops were not the open forum for dialogue we expected.
?Stakeholders in working groups tended to switch to "political mode" very quickly.?Stakeholders (also) had their own agenda.
? A vocal minority dominated workshops.
?The importance of facilitation at professional workshops was neglected.
?Facilitator costs were high if facilitators were used extensively.
Table 1 lists an interpretation of the stakeholder engagement process in the case study with respect to strengths, weaknesses, opportunities and threats.
If we compare our results with ordinary Strength, Weaknesses, Opportunities and Threats (SWOT) analysis for public participation, then we did not experience particular strengths such as “Brings out technical knowledge from the public and others” or “Allows the public to understand the system better”. However, we obtained data not known by the authorities or experts. We have also identified issues not thought of such as the barriers to voluntary farmer contracts which we would not have expected if we had based the work solely on expert assessments, e.g. the report prepared by KVL (Rasmussen, 2003).
T able 1 Strength, Weakness, Opportunity and Threats (SWOT) analysis of stakeholder engagement process.
Strengths Public participation can...
Weaknesses
Public participation can be
weakened by...
Opportunities
Public participation offers the
opportunity to...
Threats
Public participation can be
threatened if...
Make use of local and citizen knowledge not known by
authorities A lack of resources (time,
money, staff)
Build trust and capacity The public thinks that the
process is a formality (that
minds are already made up)
Encourage diverse perspec-tives (and thus encourage
issues not thought of)A lack of rules for participa-
tion
Empower people by start-
ing a dialogue and improving
openness
Enable a better evaluation of
the issues A lack of in-depth involvement
of authorities
Expand the limits of under-
standing (working together to
solve problems)
A vocal minority dominates
public meetings
A lack of hands-on BN for
stakeholders
Improve the accountability of
stakeholders
A lack of professional su-
pervision of the stakeholder
involvement process
Certainly, stakeholder engagement has given CE and GEUS a great deal of valuable experience (learning), both about how to run such processes more efficiently and transparently and how to plan the entire stakeholder involvement process more carefully. Problems encountered in BN development:?Stakeholder input to networks and probability tables (numbers) required individual meetings.
(Workshops were not enough, even if tables were presented carefully.)
?It was not that easy to understand the networks (a way of thinking that requires a little practice), if not properly explained
?Difficult to motivate stakeholders to become involved in BN development: “BN is a toy for researchers.” “Water managers without hands-on experience with the BN won’t easily understand it.”
?Problems with conditional probability tables in different stakeholder groups.
?We did not receive as much input to the BNs as expected from stakeholders.
BNs can help formulate environmental management strategies by allowing users to build their own decision support system that meets their needs, helping users to understand the nature of their decisions better, and encouraging users to deal with uncertainty and to consult stakeholders and members of the general public. Without consultation of stakeholders and general public, it is unlikely that you will be able to implement your decision.
Table 2 contains an interpretation of BNs with respect to strengths, weaknesses, opportunities and threats based on our experience.
An important characteristic of BNs is that the tool can be used “interactively” for uncertainty assessment and communication with the stakeholders involved. However, it is important to apply a kind of “protocol” for BN construction in order to explain to stakeholders, experts, users, etc. what input is required at different stages of the development.
9. DISCUSSION
The results of the case study showed “a paradox”. On the one hand, BN’s can create space for an open and non-deterministic dialogue with stakeholders due to the flexibility of the decision support tool. This allowed factors (nodes), associations (directed links) and probabilities of the graphical model to be adjusted, reconstructed and validated throughout the process and based on inputs from all involved stakeholders and experts. This means that BN’s were powerful for integrating data and knowledge from different domain experts and capable of handling uncertain information in a practical and easily understandable manner. Constructing the qualitative part of a belief network (nodes and links), although elaborate, seemed relatively straightforward and experts seemed comfortable doing so. This part of the net was relatively easily communicated to stakeholders.
On the other hand, getting stakeholders, general public and even experts to understand and accept the idea behind the BN’s used for decision making was a demanding task (Varis and Kuikka, 1999). Especially the required probability assessments for the BN’s were not easy to understand or accept by stakeholders. Even domain experts had problems to express all these probabilities numerically, something they were reluctant to do. So the quantitative part, with the probabilities over the variables, was more problematic.
Probabilities offer an alternative approach to communicating data and model results which takes advantage of the ability of people to understand outcomes presented in probabilistic language. Instead of a pesticide concentration of 0.12 μg/l simulated by a model, which is likely to be received with scepticism by stakeholders because it does not account for natural variability in the system, the information should be presented categorically in the following form: “There is a 37% probability that the concentration will be below 0.01 μg/l, a 51.5% probability that it will be between 0.01 and 0.1 μg/l, and a 11.5% probability that it will be greater than 0.1μg/l.”
One reason why probabilistic information of this form is useful is that it lends itself to evaluating the risk associated with different alternatives. Probabilities can be multiplied by the potential cost or benefit of different outcomes in order to elicit the “expected value” of a decision. Expected values of different management alternatives can then be compared to aid decision-makers in selecting an option. Additionally, the risk of an outcome can be interpreted as a margin of safety associated with the option. In a BN, this is done by introducing “utility nodes” that perform risk assessment by multiplying and adding total costs or benefits (in monetary value or other type of utility). When applying the precautionary approach in groundwater protection, the role of uncertainty is vital: the higher it is, the lower the pressures allowed from various non-point and point pollution sources should be. In addition, recent paradigms for risk-informed decision-making call for a participatory procedure in which the various stakeholders become involved early on in the risk assessment process to “characterise” risks even before a formal assessment of them is made. This does not diminish the role of modelling and quantification, but is aimed at eliciting the “values” and the perspectives of the community involved so that the multiple dimensions of risk can be taken into account early in the assessment.
Decision-makers need to be informed not only of the available scientific knowledge but also of policy-relevant uncertainties and lacunae in the knowledge base (Levin et al., 2003). For this to be possible, uncertainties must be transparently discussed and communicated.
A key problem with the probabilistic approach is that most people feel more at ease with verbal probability expressions than with numbers. When people communicate probabilities, they frequently do so in words rather than in numbers. So when it comes to reasoning and to communicating the results of BNs to users, the mode in which people normally represent probability must be taken into account as well (Renooij et al., 1999). This has often been considered a major obstacle, one of the reasons being that experts are reluctant to provide numerical probabilities. However, recent research activities have made some progress in this field by developing a
T able 2. Strengths, weaknesses, opportunities and threats of BNs as decision support tool for
water resource management
Strengths Weaknesses Opportunities Threats
Excellent for structural learning, elegant statistical approach and data mining for analysis of complex systems Dif? cult to understand for
non-experts
Possible to understand for
representatives of general
public if explained properly by
the specialists
Not easily understood if not
properly explained
Easy to develop a BBN with nodes and directed links and update it with input from
stakeholders Feedback nodes are not al-lowed; some problems in the real world cause strong
feedback
Social and ecological issues can be incorporated and coupled with hydrology The interdisciplinary approach
raises problems with organis-
ing knowledge input and data
input (academic territories,
illusion of techniques)
The opportunity to work with
more disciplines
Over-expectations with re-
spect to modelling capabilities
Excellent for strategic consid-erations (indicators, actions and additional data require-
ments)
Expert knowledge and data can be combined and modi? ed/balanced through stakeholder involvement Requires panel of expert input for all domains => resources and time (equivalent to nu-
merical models)
Improves conversation/ dia-logue with stakeholders
T oo much ”hot air”/soft dis-
cussion (dif? cult to govern the
process;”focused stakeholders”)
New problems can be struc-
tured and analysed quickly
Very useful for complex sys-
tems There is a danger that use of
BBNs causes ignoring of real
data and knowledge
Political manipulation
Excellent for integration and breakdown of barriers between different domains, e.g. economy, hydrology, ecol-ogy, social (different time and spatial aggregation) Not useful for implementa-
tion of speci? c protection
zones (physical-based model
required)
Holistic approach BBNs describe an understand-
ing of the system and pro-
cesses that are not physically
based (more information ? ow
than mass ? ow). Non-linearity
not incorporated.
Can be used even if data sets are incomplete The BBN hides the complex-ity of the system from the users (underlying conditional probability tables are rather
complex!)
Ability to predict future state of systems based on simpli? ed
assumptions Data manipulation is possible
(it is easy to get carried away)
A possible tool when dealing
with water managers sceptical
about comprehensive models
and questioning the need for
catchment modelling
Experts do not want to pro-
vide input for the conditional
probability tables (numbers):
defending academic territo-
ries!
It is possible to “validate” the importance of value and belief when consulting stakeholders.
BBNs work on “aggregated data” (probabilities). Not possible to utilise all collected data (temporal and spatial variation/information in data)
probability scale that contains words as well as numbers (Renooij et al., 1999; Witteman and Renooij,2003; Gaag et al., 2002).
The objective of our study was to present and discuss the methodology adapted for the construction and validation of a Bayesian belief network for groundwater protection based on the active involvement of stakeholders and general public. The case study showed that it was possible to engage stakeholders and general public in construction and validation of a BN for preventive groundwater protection against pesticides.
BNs were useful for water resource scientists and water managers dealing with complex problems by permitting carefully elicited expert knowledge as a practical alternative to “hard” data, and facilitating extension of models to ecological and socio-economical endpoints (Borsuk et all., 2003). This leads us to the following conclusions regarding BNs as a decision support tool. BNs demonstrated several advantages compared to traditional approaches. BNs enabled locally based solutions (more than before). They provided local acceptance of decisions and solutions and improved the dialogue between the water company, local stakeholders and authorities. They encouraged diverse perspectives (and thus identified issues not thought of). They enabled a better evaluation of the issues. They made use of local and citizen knowledge not known by the authorities (Henriksen et al., 2004), see fig. 4. The weaknesses of BNs as a decision support tool were the time-consuming and long-lasting process in construction and evaluation of BNs, which had to be properly organised and conducted. This means that, if there is a lack of resources (time, money, staff), rules for participation, in-depth involvement of authorities,hands-on BN for the stakeholders and professional supervision of the stakeholder involvement process,then the credibility of the BNs are likely to be
questioned by stakeholders and general public.
Risk of lacking support by stakeholders during implementation phase Benefits of BNs in
stakeholder involvement process
T ype of stakeholder engagement
T ype 1Information
T ype 2Consultation
T ype 3Full involvement
High
Low
Fig. 4. Type of stakeholder engagement compared to risk of lack of support and the benefits of BNs in the stakeholder involvement process
Regarding involvement of stakeholders and general public (Mostert 2003a,b) in BN development we made the following observations in the case study:
? Stakeholders had an impact on the BN
development (on variables, links and CPT’s,e.g. ‘perception of vulnerability’ variable and behaviour of farmers in relation to compensation payment)
? Evaluation of BNs with input from
stakeholders and general public was a necessary step.
? In the early, more qualitative stages, broader
groups of stakeholders and the general public provided relevant input to BN development.
? In the later, more quantitative stages, it was
better to consult stakeholders and members of the general public at individual meetings or maybe in stakeholder and citizens’ groups that each focused on a “domain of interest”because they were reluctant to give quantitative inputs in larger groups.
? Experts were necessary for quantitative input
to BNs. In the case study, we had two experts in farming economics and socioeconomics in addition to the geological and hydrological experts from CE and GEUS. It would have been an advantage in BN development if the panel of experts had included an expert on biodiversity and/or pesticide-exposed aquatic environment as well.
? The results of BNs must be followed by a
detailed description of the parameters used and why, plus a description of the results and their consequences in order to make BNs as transparent as possible. It is much too risky to allow politicians or civil servants to make decisions based on the "naked" data. So one should rather allow stakeholders and citizens to become more involved
? It was important to provide users with more
easily understandable explanations of the results, for which numbers not necessarily was the best option, and verbal communication is a necessary alternative.Furthermore, an expert’s assessments may reflect various biases, where an expert consistently gives probability assessments that are higher or lower than they should be. ? In order to provide a credible BN it was
necessary to engage stakeholder groups in the validation of BN’s. This was a crucial and demanding task.
10. CONCLUSION
In conclusion, the use of BNs went beyond information and consultation and required the full involvement of stakeholders in their construction and validation. The advantage was a reduced risk of lack of support by stakeholders during the implementation
phase of a given action plan. The benefits of BNs were greatest when there was a high degree of interaction between researchers, users, water managers, stakeholders and general public.
?BNs are most powerful when integrating different domains, e.g. physical, social, economic and ecological, in the early stages of preparing a management plan with the involvement of stakeholder groups and general public (Mostert 2003a,b)
? A panel of experts is valuable in covering each domain included, for providing proper input and/or for reviewing the results from the BNs developed.
?Clear rules of the game are important: it is necessary to prepare a stakeholder involvement
plan describing how to involve stakeholders and
general public which is balanced with respect to
problem framing and the type of decision support system used for planning and implementation.?It is better to involve stakeholders and public in “temporary” groups or at individual meetings
when direct input is required, especially when
collecting data for BNs; feedback on states, links and CPTs than it is to run the process with broad, permanent groups of stakeholders and citizens’.?Don’t be afraid of actively involving citizens: but be careful to inform and explain properly about
the tasks and goals and do always allow feedback and comments on the BN development process
by presenting the graphical model and easily
understood descriptions and results.
?If representatives of the general public are involved, be sure there is enough time and money to run the process according to the stakeholder involvement plan.
ACKNOWLEDGEMENT
The present work was carried out within the Project ‘Management of the Environment and Resources using Integrated Techniques (MERIT)’, which is partly funded by the EC Energy, Environment and Sustainable Development programme (Contract EVK1-CT-2000-00085).
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(2001) The SACSO methodology for troubleshooting complex systems; Artificial Intelligence for Engineering, Design, Analysis and Manufacturing, 15, 321-333.
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常用二极管参数
常用整流二极管 型号VRM/Io IFSM/ VF /Ir 封装用途说明1A5 600V/1.0A 25A/1.1V/5uA[T25] D2.6X3.2d0.65 1A6 800V/1.0A 25A/1.1V/5uA[T25] D2.6X3.2d0.65 6A8 800V/6.0A 400A/1.1V/10uA[T60] D9.1X9.1d1.3 1N4002 100V/1.0A 30A/1.1V/5uA[T75] D2.7X5.2d0.9 1N4004 400V/1.0A 30A/1.1V/5uA[T75] D2.7X5.2d0.9 1N4006 800V/1.0A 30A/1.1V/5uA[T75] D2.7X5.2d0.9 1N4007 1000V/1.0A 30A/1.1V/5uA[T75] D2.7X5.2d0.9 1N5398 800V/1.5A 50A/1.4V/5uA[T70] D3.6X7.6d0.9 1N5399 1000V/1.5A 50A/1.4V/5uA[T70] D3.6X7.6d0.9 1N5402 200V/3.0A 200A/1.1V/5uA[T105] D5.6X9.5d1.3 1N5406 600V/3.0A 200A/1.1V/5uA[T105] D5.6X9.5d1.3 1N5407 800V/3.0A 200A/1.1V/5uA[T105] D5.6X9.5d1.3 1N5408 1000V/3.0A 200A/1.1V/5uA[T105] D5.6X9.5d1.3 RL153 200V/1.5A 60A/1.1V/5uA[T75] D3.6X7.6d0.9 RL155 600V/1.5A 60A/1.1V/5uA[T75] D3.6X7.6d0.9 RL156 800V/1.5A 60A/1.1V/5uA[T75] D3.6X7.6d0.9 RL203 200V/2.0A 70A/1.1V/5uA[T75] D3.6X7.6d0.9 RL205 600V/2.0A 70A/1.1V/5uA[T75] D3.6X7.6d0.9 RL206 800V/2.0A 70A/1.1V/5uA[T75] D3.6X7.6d0.9 RL207 1000V/2.0A 70A/1.1V/5uA[T75] D3.6X7.6d0.9 RM11C 1000V/1.2A 100A/0.92V/10uA D4.0X7.2d0.78 MR750 50V/6.0A 400A/1.25V/25uA D8.7x6.3d1.35 MR751 100V/6.0A 400A/1.25V/25uA D8.7x6.3d1.35 MR752 200V/6.0A 400A/1.25V/25uA D8.7x6.3d1.35 MR754 400V/6.0A 400A/1.25V/25uA D8.7x6.3d1.35 MR756 600V/6.0A 400A/1.25V/25uA D8.7x6.3d1.35 MR760 1000V/6.0A 400A/1.25V/25uA D8.7x6.3d1.35 常用整流二极管(全桥） 型号VRM/Io IFSM/ VF /Ir 封装用途说明RBV-406 600V/*4A 80A/1.10V/10uA 25X15X3.6 RBV-606 600V/*6A 150A/1.05V/10uA 30X20X3.6 RBV-1306 600V/*13A 80A/1.20V/10uA 30X20X3.6 RBV-1506 600V/*15A 200A/1.05V/50uA 30X20X3.6 RBV-2506 600V/*25A 350A/1.05V/50uA 30X20X3.6 常用肖特基整流二极管SBD 型号VRM/Io IFSM/ VF Trr1/Trr2 封装用途说明EK06 60V/0.7A 10A/0.62V 100nS D2.7X5.0d0.6 SK/高速 EK14 40V/1.5A 40A/0.55V 200nS D4.0X7.2d0.78 SK/低速 D3S6M 60V/3.0A 80A/0.58V 130p SB340 40V/3.0A 80A/0.74V 180p SB360 60V/3.0A 80A/0.74V 180p SR260 60V/2.0A 50A/0.70V 170p MBR1645 45V/16A 150A/0.65V <10nS TO220 超高速
常用二极管参数
常用二极管参数 2008-10-22 11:48 05Z6.2Y 硅稳压二极管 Vz=6~6.35V, Pzm=500mW, 05Z7.5Y 硅稳压二极管 Vz=7.34~7.70V, Pzm=500mW, 05Z13X 硅稳压二极管 Vz=12.4~13.1V, Pzm=500mW, 05Z15Y 硅稳压二极管 Vz=14.4~15.15V, Pzm=500mW, 05Z18Y 硅稳压二极管 Vz=17.55~18.45V, Pzm=500mW, 1N4001 硅整流二极管 50V, 1A,(Ir=5uA, Vf=1V, Ifs=50A) 1N4002 硅整流二极管 100V, 1A, 1N4003 硅整流二极管 200V, 1A, 1N4004 硅整流二极管 400V, 1A, 1N4005 硅整流二极管 600V, 1A, 1N4006 硅整流二极管 800V, 1A, 1N4007 硅整流二极管 1000V, 1A, 1N4148 二极管 75V, 4PF, Ir=25nA, Vf=1V, 1N5391 硅整流二极管 50V, 1.5A,(Ir=10uA, Vf=1.4V, Ifs=50A) 1N5392 硅整流二极管 100V, 1.5A, 1N5393 硅整流二极管 200V, 1.5A, 1N5394 硅整流二极管 300V, 1.5A, 1N5395 硅整流二极管 400V, 1.5A, 1N5396 硅整流二极管 500V, 1.5A, 1N5397 硅整流二极管 600V, 1.5A, 1N5398 硅整流二极管 800V, 1.5A, 1N5399 硅整流二极管 1000V, 1.5A, 1N5400 硅整流二极管 50V, 3A,(Ir=5uA, Vf=1V, Ifs=150A) 1N5401 硅整流二极管 100V, 3A, 1N5402 硅整流二极管 200V, 3A, 1N5403 硅整流二极管 300V, 3A, 1N5404 硅整流二极管 400V, 3A, 1N5405 硅整流二极管 500V, 3A, 1N5406 硅整流二极管 600V, 3A, 1N5407 硅整流二极管 800V, 3A, 1N5408 硅整流二极管 1000V, 3A, 1S1553 硅开关二极管 70V, 100mA, 300mW, 3.5PF, 300ma, 1S1554 硅开关二极管 55V, 100mA, 300mW, 3.5PF, 300ma, 1S1555 硅开关二极管 35V, 100mA, 300mW, 3.5PF, 300ma, 1S2076 硅开关二极管 35V, 150mA, 250mW, 8nS, 3PF, 450ma, Ir≤1uA, Vf≤0.8V,≤1.8PF, 1S2076A 硅开关二极管 70V, 150mA, 250mW, 8nS, 3PF, 450ma, 60V, Ir≤1uA, Vf≤0.8V,≤1.8PF, 1S2471 硅开关二极管80V, Ir≤0.5uA, Vf≤1.2V,≤2PF, 1S2471B 硅开关二极管 90V, 150mA, 250mW, 3nS, 3PF, 450ma, 1S2471V 硅开关二极管 90V, 130mA, 300mW, 4nS, 2PF, 400ma, 1S2472 硅开关二极管50V, Ir≤0.5uA, Vf≤1.2V,≤2PF, 1S2473 硅开关二极管35V, Ir≤0.5uA, Vf≤1.2V,≤3PF,
joinin剑桥小学英语
Join In剑桥小学英语(改编版)入门阶段Unit 1Hello,hello第1单元嗨,嗨 and mime. 1 听,模仿 Stand up Say 'hello' Slap hands Sit down 站起来说"嗨" 拍手坐下来 Good. Let's do up Say 'hello' Slap hands Sit down 好. 我们来再做一遍.站起来说"嗨"拍手坐下来 the pictures. 2 再听一遍给图画编号. up "hello" hands down 1 站起来 2 说"嗨" 3 拍手 4 坐下来说 3. A ,what's yourname 3 一首歌嗨,你叫什么名字 Hello. , what's yourname Hello. Hello. 嗨. 嗨. 嗨, 你叫什么名字嗨,嗨. Hello, what's yourname I'm Toby. I'm Toby. Hello,hello,hello.嗨, 你叫什么名字我叫托比. 我叫托比 . 嗨,嗨,嗨. I'm Toby. I'm Toby. Hello,hello, let's go! 我是托比. 我是托比. 嗨,嗨, 我们一起! Hello. , what's yourname I'm 'm Toby. 嗨.嗨.嗨, 你叫什么名字我叫托比.我叫托比. Hello,hello,hello. I'm 'm Toby. Hello,hello,let's go! 嗨,嗨,嗨.我是托比. 我是托比. 嗨,嗨,我们一起! 4 Listen and stick 4 听和指 What's your name I'm Bob. 你叫什么名字我叫鲍勃. What's your name I'm Rita. What's your name I'm Nick. 你叫什么名字我叫丽塔. 你叫什么名字我叫尼克. What's your name I'm Lisa. 你叫什么名字我叫利萨. 5. A story-Pit'sskateboard. 5 一个故事-彼德的滑板. Pa:Hello,Pit. Pa:好,彼德. Pi:Hello,:What's this Pi:嗨,帕特.Pa:这是什么 Pi:My new :Look!Pi:Goodbye,Pat! Pi:这是我的新滑板.Pi:看!Pi:再见,帕特! Pa:Bye-bye,Pit!Pi:Help!Help!pi:Bye-bye,skateboard! Pa:再见,彼德!Pi:救命!救命!Pi:再见,滑板! Unit 16. Let's learnand act 第1单元6 我们来边学边表演.
常用二极管型号及参数大全精编版
1.塑封整流二极管 序号型号IF VRRM VF Trr 外形 A V V μs 1 1A1-1A7 1A 50-1000V 1.1 R-1 2 1N4001-1N4007 1A 50-1000V 1.1 DO-41 3 1N5391-1N5399 1.5A 50-1000V 1.1 DO-15 4 2A01-2A07 2A 50-1000V 1.0 DO-15 5 1N5400-1N5408 3A 50-1000V 0.95 DO-201AD 6 6A05-6A10 6A 50-1000V 0.95 R-6 7 TS750-TS758 6A 50-800V 1.25 R-6 8 RL10-RL60 1A-6A 50-1000V 1.0 9 2CZ81-2CZ87 0.05A-3A 50-1000V 1.0 DO-41 10 2CP21-2CP29 0.3A 100-1000V 1.0 DO-41 11 2DZ14-2DZ15 0.5A-1A 200-1000V 1.0 DO-41 12 2DP3-2DP5 0.3A-1A 200-1000V 1.0 DO-41 13 BYW27 1A 200-1300V 1.0 DO-41 14 DR202-DR210 2A 200-1000V 1.0 DO-15 15 BY251-BY254 3A 200-800V 1.1 DO-201AD 16 BY550-200～1000 5A 200-1000V 1.1 R-5 17 PX10A02-PX10A13 10A 200-1300V 1.1 PX 18 PX12A02-PX12A13 12A 200-1300V 1.1 PX 19 PX15A02-PX15A13 15A 200-1300V 1.1 PX 20 ERA15-02～13 1A 200-1300V 1.0 R-1 21 ERB12-02～13 1A 200-1300V 1.0 DO-15 22 ERC05-02～13 1.2A 200-1300V 1.0 DO-15 23 ERC04-02～13 1.5A 200-1300V 1.0 DO-15 24 ERD03-02～13 3A 200-1300V 1.0 DO-201AD 25 EM1-EM2 1A-1.2A 200-1000V 0.97 DO-15 26 RM1Z-RM1C 1A 200-1000V 0.95 DO-15 27 RM2Z-RM2C 1.2A 200-1000V 0.95 DO-15 28 RM11Z-RM11C 1.5A 200-1000V 0.95 DO-15 29 RM3Z-RM3C 2.5A 200-1000V 0.97 DO-201AD 30 RM4Z-RM4C 3A 200-1000V 0.97 DO-201AD 2.快恢复塑封整流二极管 序号型号IF VRRM VF Trr 外形 A V V μs （1）快恢复塑封整流二极管 1 1F1-1F7 1A 50-1000V 1.3 0.15-0.5 R-1 2 FR10-FR60 1A-6A 50-1000V 1. 3 0.15-0.5 3 1N4933-1N4937 1A 50-600V 1.2 0.2 DO-41 4 1N4942-1N4948 1A 200-1000V 1.3 0.15-0. 5 DO-41 5 BA157-BA159 1A 400-1000V 1.3 0.15-0.25 DO-41 6 MR850-MR858 3A 100-800V 1.3 0.2 DO-201AD
常用稳压二极管大全,
常用稳压管型号对照——（朋友发的） 美标稳压二极管型号 1N4727 3V0 1N4728 3V3 1N4729 3V6 1N4730 3V9 1N4731 4V3 1N4732 4V7 1N4733 5V1 1N4734 5V6 1N4735 6V2 1N4736 6V8 1N4737 7V5 1N4738 8V2 1N4739 9V1 1N4740 10V 1N4741 11V 1N4742 12V 1N4743 13V 1N4744 15V 1N4745 16V 1N4746 18V 1N4747 20V 1N4748 22V 1N4749 24V 1N4750 27V 1N4751 30V 1N4752 33V 1N4753 36V 1N4754 39V 1N4755 43V 1N4756 47V 1N4757 51V 需要规格书请到以下地址下载， 经常看到很多板子上有M记的铁壳封装的稳压管，都是以美标的1N系列型号标识的，没有具体的电压值，刚才翻手册查了以下3V至51V的型号与电压的对 照值，希望对大家有用 1N4727 3V0 1N4728 3V3 1N4729 3V6 1N4730 3V9
1N4733 5V1 1N4734 5V6 1N4735 6V2 1N4736 6V8 1N4737 7V5 1N4738 8V2 1N4739 9V1 1N4740 10V 1N4741 11V 1N4742 12V 1N4743 13V 1N4744 15V 1N4745 16V 1N4746 18V 1N4747 20V 1N4748 22V 1N4749 24V 1N4750 27V 1N4751 30V 1N4752 33V 1N4753 36V 1N4754 39V 1N4755 43V 1N4756 47V 1N4757 51V DZ是稳压管的电器编号，是和1N4148和相近的，其实1N4148就是一个0.6V的稳压管，下面是稳压管上的编号对应的稳压值，有些小的稳压管也会在管体 上直接标稳压电压，如5V6就是5.6V的稳压管。 1N4728A 3.3 1N4729A 3.6 1N4730A 3.9 1N4731A 4.3 1N4732A 4.7 1N4733A 5.1 1N4734A 5.6 1N4735A 6.2 1N4736A 6.8 1N4737A 7.5 1N4738A 8.2 1N4739A 9.1 1N4740A 10 1N4741A 11 1N4742A 12 1N4743A 13
Join In剑桥小学英语.doc
Join In剑桥小学英语(改编版)入门阶段 Unit 1Hello,hello第1单元嗨,嗨 1.Listen and mime. 1 听,模仿 Stand up Say 'hello' Slap hands Sit down 站起来说"嗨" 拍手坐下来 Good. Let's do itagain.Stand up Say 'hello' Slap hands Sit down 好. 我们来再做一遍.站起来说"嗨"拍手坐下来 2.listen again.Number the pictures. 2 再听一遍给图画编号. 1.Stand up 2.Say "hello" 3.Slap hands 4.Sit down 1 站起来 2 说"嗨" 3 拍手 4 坐下来说 3. A song.Hello,what's yourname? 3 一首歌嗨,你叫什么名字? Hello. Hello.Hello, what's yourname? Hello. Hello. 嗨. 嗨. 嗨, 你叫什么名字? 嗨,嗨. Hello, what's yourname? I'm Toby. I'm Toby. Hello,hello,hello. 嗨, 你叫什么名字? 我叫托比. 我叫托比 . 嗨,嗨,嗨. I'm Toby. I'm Toby. Hello,hello, let's go! 我是托比. 我是托比. 嗨,嗨, 我们一起! Hello. Hello.Hello, what's yourname? I'm Toby.I'm Toby. 嗨.嗨.嗨, 你叫什么名字? 我叫托比.我叫托比. Hello,hello,hello. I'm Toby.I'm Toby. Hello,hello,let's go! 嗨,嗨,嗨.我是托比. 我是托比. 嗨,嗨,我们一起! 4 Listen and stick 4 听和指 What's your name? I'm Bob. 你叫什么名字? 我叫鲍勃. What's your name ? I'm Rita. What's your name ? I'm Nick. 你叫什么名字? 我叫丽塔. 你叫什么名字? 我叫尼克. What's your name ? I'm Lisa. 你叫什么名字? 我叫利萨. 5. A story-Pit'sskateboard. 5 一个故事-彼德的滑板. Pa:Hello,Pit. Pa:好,彼德. Pi:Hello,Pat.Pa:What's this? Pi:嗨,帕特.Pa:这是什么? Pi:My new skateboard.Pi:Look!Pi:Goodbye,Pat! Pi:这是我的新滑板.Pi:看!Pi:再见,帕特! Pa:Bye-bye,Pit!Pi:Help!Help!pi:Bye-bye,skateboard! Pa:再见,彼德!Pi:救命!救命!Pi:再见,滑板! Unit 16. Let's learnand act 第1单元6 我们来边学边表演.
二极管封装大全
二极管封装大全 篇一：贴片二极管型号、参数 贴片二极管型号.参数查询 1、肖特基二极管SMA（DO214AC） 2010-2-2 16:39:35 标准封装： SMA 2010 SMB 2114 SMC 3220 SOD123 1206 SOD323 0805 SOD523 0603 IN4001的封装是1812 IN4148的封装是1206 篇二：常见贴片二极管三极管的封装 常见贴片二极管/三极管的封装 常见贴片二极管/三极管的封装 二极管： 名称尺寸及焊盘间距其他尺寸相近的封装名称 SMC SMB SMA SOD-106 SC-77A SC-76/SC-90A SC-79 三极管： LDPAK
DPAK SC-63 SOT-223 SC-73 TO-243/SC-62/UPAK/MPT3 SC-59A/SOT-346/MPAK/SMT3 SOT-323 SC-70/CMPAK/UMT3 SOT-523 SC-75A/EMT3 SOT-623 SC-89/MFPAK SOT-723 SOT-923 VMT3 篇三：常用二极管的识别及ic封装技术 常用晶体二极管的识别 晶体二极管在电路中常用“D”加数字表示，如： D5表示编号为5的二极管。 1、作用：二极管的主要特性是单向导电性，也就是在正向电压的作用下，导通电阻很小;而在反向电压作用下导通电阻极大或无穷大。正因为二极管具有上述特性，无绳电话机中常把它用在整流、隔离、稳压、极性保护、编码控制、调频调制和静噪等电路中。 电话机里使用的晶体二极管按作用可分为：整流二极管(如1N4004)、隔离二极管(如1N4148)、肖特基二极管(如BAT85)、发光二极管、稳压二极管等。 2、识别方法：二极管的识别很简单，小功率二极管的N极(负极)，在二极管外表大多采用一种色圈标出来，有些二极管也用二极管专用符号来表示P极(正极)或N极(负极)，也有采用符号标志为“P”、“N”来确定二极管极性的。发光二极管的正负极可从引脚长短来识别，长
1N系列常用整流二极管的主要参数
1N 系列常用整流二极管的主要参数
反向工作 峰值电压 URM/V 额定正向 整流电流 整流电流 IF/A 正向不重 复浪涌峰 值电流 IFSM/A 正向 压降 UF/V 反向 电流 IR/uA 工作 频率 f/KHZ 外形 封装
型 号
1N4000 1N4001 1N4002 1N4003 1N4004 1N4005 1N4006 1N4007 1N5100 1N5101 1N5102 1N5103 1N5104 1N5105 1N5106 1N5107 1N5108 1N5200 1N5201 1N5202 1N5203 1N5204 1N5205 1N5206 1N5207 1N5208 1N5400 1N5401 1N5402 1N5403 1N5404 1N5405 1N5406 1N5407 1N5408
25 50 100 200 400 600 800 1000 50 100 200 300 400 500 600 800 1000 50 100 200 300 400 500 600 800 1000 50 100 200 300 400 500 600 800 1000
1
30
≤1
＜5
3
DO-41
1．5
75
≤1
＜5
3
DO-15
2
100
≤1
＜10
3
3
150
≤0.8
＜10
3
DO-27
常用二极管参数： 05Z6.2Y 硅稳压二极管 Vz=6~6.35V,Pzm=500mW,
最新公司注册登记(备案)申请书
公司登记（备案）申请书 注：请仔细阅读本申请书《填写说明》，按要求填写。 □基本信息 名称 名称预先核准文号/ 注册号/统一 社会信用代码 住所 省（市/自治区）市（地区/盟/自治州）县（自治县/旗/自治旗/市/区）乡（民族乡/镇/街道）村（路/社区）号 生产经营地 省（市/自治区）市（地区/盟/自治州）县（自治县/旗/自治旗/市/区）乡（民族乡/镇/街道）村（路/社区）号 联系电话邮政编码 □设立 法定代表人 姓名 职务□董事长□执行董事□经理注册资本万元公司类型 设立方式 （股份公司填写） □发起设立□募集设立经营范围 经营期限□年□长期申请执照副本数量个
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剑桥小学英语Join_In
《剑桥小学英语Join In ——Book 3 下学期》教材教法分析2012-03-12 18:50:43| 分类：JOIN IN 教案| 标签：|字号大中小订阅. 一、学情分析： 作为毕业班的学生，六年级的孩子在英语学习上具有非常显著的特点： 1、因为教材的编排体系和课时不足，某些知识学生已遗忘，知识回生的现象很突出。 2、有的学生因受学习习惯及学习能力的制约，有些知识掌握较差，学生学习个体的差异性，学习情况参差不齐、两级分化的情况明显，对英语感兴趣的孩子很喜欢英语，不喜欢英语的孩子很难学进去了。 3、六年级的孩子已经进入青春前期，他们跟三、四、五年级的孩子相比已经有了很大的不同。他们自尊心强，好胜心强，集体荣誉感也强，有自己的评判标准和思想，对知识的学习趋于理性化，更有自主学习的欲望和探索的要求。 六年级学生在英语学习上的两极分化已经给教师的教学带来很大的挑战，在教学中教师要注意引导学生调整学习方式： 1、注重培养学生自主学习的态度 如何抓住学习课堂上的学习注意力，吸引他们的视线，保持他们高涨的学习激情，注重过程的趣味化和学习内容的简易化。 2、给予学生独立思考的空间。 3、鼓励学生坚持课前预习、课后复习的好习惯。 六年级教材中的单词、句子量比较多，难点也比较多，学生课前回家预习，不懂的地方查英汉词典或者其它资料，上课可以达到事半功倍的效果，课后复习也可以很好的消化课堂上的内容。 4、注意培养学生合作学习的习惯。 5、重在培养学生探究的能力：学习内容以问题的方式呈现、留给学生更多的发展空间。 二、教材分析： （一）.教材特点： 1．以学生为主体，全面提高学生的素质。
常见二极管参数大全
1N系列稳压管
快恢复整流二极管
常用整流二极管型号和参数 05Z6.2Y 硅稳压二极管 Vz=6~6.35V,Pzm=500mW, 05Z7.5Y 硅稳压二极管 Vz=7.34~7.70V,Pzm=500mW, 05Z13X硅稳压二极管 Vz=12.4~13.1V,Pzm=500mW, 05Z15Y硅稳压二极管 Vz=14.4~15.15V,Pzm=500mW, 05Z18Y硅稳压二极管 Vz=17.55~18.45V,Pzm=500mW, 1N4001硅整流二极管 50V, 1A,(Ir=5uA,Vf=1V,Ifs=50A) 1N4002硅整流二极管 100V, 1A, 1N4003硅整流二极管 200V, 1A, 1N4004硅整流二极管 400V, 1A, 1N4005硅整流二极管 600V, 1A, 1N4006硅整流二极管 800V, 1A, 1N4007硅整流二极管 1000V, 1A, 1N4148二极管 75V, 4PF,Ir=25nA,Vf=1V, 1N5391硅整流二极管 50V, 1.5A,(Ir=10uA,Vf=1.4V,Ifs=50A) 1N5392硅整流二极管 100V,1.5A, 1N5393硅整流二极管 200V,1.5A, 1N5394硅整流二极管 300V,1.5A, 1N5395硅整流二极管 400V,1.5A, 1N5396硅整流二极管 500V,1.5A, 1N5397硅整流二极管 600V,1.5A, 1N5398硅整流二极管 800V,1.5A, 1N5399硅整流二极管 1000V,1.5A, 1N5400硅整流二极管 50V, 3A,(Ir=5uA,Vf=1V,Ifs=150A) 1N5401硅整流二极管 100V,3A, 1N5402硅整流二极管 200V,3A, 1N5403硅整流二极管 300V,3A, 1N5404硅整流二极管 400V,3A,
有限合伙企业登记注册操作指南
有限合伙企业登记注册操作指南 风险控制部 20xx年x月xx日
目录 一、合伙企业的概念 (4) 二、有限合伙企业应具备的条件 (4) 三、有限合伙企业设立具备的条件 (4) 四、注册有限合伙企业程序 (5) 五、申请合伙企业登记注册应提交文件、证件 (6) （一）合伙企业设立登记应提交的文件、证件： (6) （二）合伙企业变更登记应提交的文件、证件： (7) （三）合伙企业注销登记应提交的文件、证件： (8) （四）合伙企业申请备案应提交的文件、证件： (9) （五）其他登记应提交的文件、证件： (9) 六、申请合伙企业分支机构登记注册应提交的文件、证件 (9) （一）合伙企业分支机构设立登记应提交的文件、证件 (10) （二）合伙企业分支机构变更登记应提交的文件、证件： (10) （三）合伙企业分支机构注销登记应提交的文件、证件： (11) （四）其他登记应提交的文件、证件： (12) 七、收费标准 (12) 八、办事流程图 (12) （一）有限合伙企业创办总体流程图（不含专业性前置审批） (12) （二）、工商局注册程序 (15)
（三）、工商局具体办理程序（引入网上预审核、电话预约方式） (16) 九、有限合伙企业与有限责任公司的区别 (16) （一）、设立依据 (16) （二）、出资人数 (16) （三）、出资方式 (17) （四）、注册资本 (17) （五）、组织机构 (18) （六）、出资流转 (18) （七）、对外投资 (19) （八）、税收缴纳 (20) （九）、利润分配 (20) （十）、债务承担 (21) 十、常见问题解答与指导 (21)
常用稳压二极管技术参数及老型号代换.
常用稳压二极管技术参数及老型号代换 型号最大功耗 (mW) 稳定电压(V) 电流(mA) 代换型号国产稳压管日立稳压管 HZ4B2 500 3.8 4.0 5 2CW102 2CW21 4B2 HZ4C1 500 4.0 4.2 5 2CW102 2CW21 4C1 HZ6 500 5.5 5.8 5 2CW103 2CW21A 6B1 HZ6A 500 5.2 5.7 5 2CW103 2CW21A HZ6C3 500 6 6.4 5 2CW104 2CW21B 6C3 HZ7 500 6.9 7.2 5 2CW105 2CW21C HZ7A 500 6.3 6.9 5 2CW105 2CW21C HZ7B 500 6.7 7.3 5 2CW105 2CW21C HZ9A 500 7.7 8.5 5 2CW106 2CW21D HZ9CTA 500 8.9 9.7 5 2CW107 2CW21E HZ11 500 9.5 11.9 5 2CW109 2CW21G HZ12 500 11.6 14.3 5 2CW111 2CW21H HZ12B 500 12.4 13.4 5 2CW111 2CW21H HZ12B2 500 12.6 13.1 5 2CW111 2CW21H 12B2 HZ18Y 500 16.5 18.5 5 2CW113 2CW21J HZ20-1 500 18.86 19.44 2 2CW114 2CW21K HZ27 500 27.2 28.6 2 2CW117 2CW21L 27-3 HZT33-02 400 31 33.5 5 2CW119 2CW21M RD2.0E(B) 500 1.88 2.12 20 2CW100 2CW21P 2B1 RD2.7E 400 2.5 2.93 20 2CW101 2CW21S RD3.9EL1 500 3.7 4 20 2CW102 2CW21 4B2 RD5.6EN1 500 5.2 5.5 20 2CW103 2CW21A 6A1 RD5.6EN3 500 5.6 5.9 20 2CW104 2CW21B 6B2 RD5.6EL2 500 5.5 5.7 20 2CW103 2CW21A 6B1 RD6.2E(B) 500 5.88 6.6 20 2CW104 2CW21B RD7.5E(B) 500 7.0 7.9 20 2CW105 2CW21C RD10EN3 500 9.7 10.0 20 2CW108 2CW21F 11A2 RD11E(B) 500 10.1 11.8 15 2CW109 2CW21G RD12E 500 11.74 12.35 10 2CW110 2CW21H 12A1 RD12F 1000 11.19 11.77 20 2CW109 2CW21G RD13EN1 500 12 12.7 10 2CW110 2CW21H 12A3 RD15EL2 500 13.8 14.6 15 2CW112 2CW21J 12C3 RD24E 400 22 25 10 2CW116 2CW21H 24-1
剑桥小学英语join in五年级测试卷
五 年 级 英 语 测 试 卷 学校 班级 姓名 听力部分（共20分） 一、Listen and colour . 听数字，涂颜色。（5分） 二、 Listen and tick . 听录音，在相应的格子里打“√”。 （6分） 三、Listen and number.听录音，标序号。（9分） pig fox lion cow snake duck
sheep 笔试部分（共80分） 一、Write the questions.将完整的句子写在下面的横线上。(10分) got it Has eyes on a farm it live sheep a it other animals eat it it Is 二、Look and choose.看看它们是谁，将字母填入括号内。(8分) A. B. C. D.
E. F. G. H. ( ) pig ( ) fox ( ) sheep ( ) cat ( ) snake ( ) lion ( ) mouse ( ) elephant 三、Look at the pictures and write the questions.看图片，根据答语写出相应的问题。(10分) No,it doesn’t. Yes,it is.
Yes,it does. Yes,it has. Yes,it does. 四、Choose the right answer.选择正确的答案。(18分) 1、it live on a farm？ 2. it fly？
3. it a cow？ 4. it eat chicken？ 5. you swim？ 6. you all right？ 五、Fill in the numbers.对话排序。(6分) Goodbye. Two apples , please. 45P , please. Thank you.
公司注册登记流程(四证)
→客户提供：场所证明租赁协议身份证委托书三张一寸相片 →需准备材料：办理税务登记证时需要会计师资格证与财务人员劳动合同 →提交名称预审通知书→公司法定代表人签署的《公司设立登记申请书》→全体股东签署的《指定代表或者公共委托代理人的证明》（申请人填写股东姓名）→全体股东签署的公司章程（需得到工商局办事人员的认可）→股东身份证复印件→验资报告（需到计师事务所办理：需要材料有名称预审通知书复印件公司章程股东身份证复印件银行开具验资账户进账单原件银行开具询证函租赁合同及场所证明法人身份证原件公司开设临时存款账户的复印件）→任职文件（法人任职文件及股东董事会决议）→住所证明（房屋租赁合同）→工商局（办证大厅）提交所有材料→公司营业执照办理结束 →需带材料→公司营业执照正副本原件及复印件→法人身份证原件→代理人身份证→公章→办理人开具银行收据交款元工本费→填写申请书→组织机构代码证办
理结束 →需带材料→工商营业执照正副本复印件原件→组织机构正副本原件及复印件→公章→公司法定代表人签署的《公司设立登记申请书》→公司章程→股东注册资金情况表→验资报告书复印件→场所证明（租赁合同）→法人身份证复印件原件→会计师资格证（劳动合同）→税务登记证办理结束 →需带材料→工商营业执照正副本复印件原件→组织机构正副本原件及复印件→税务登记证原件及复印件→公章→法人身份证原件及复印件→代理人身份证原件及复印件→法人私章→公司验资账户→注以上复印件需四份→办理时间个工作日→办理结束 →需带材料→工商营业执照正副本复印件原件→组织机构正副本原件及复印件→公章→公司法定代表人签署的《公司设立登记申请书》→公司章程→股东注册资金情况表→验资报告书复印件→场所证明（租赁合同）→法人身份证复印件原件→会计师资格证（劳动合同）→会计制度→银行办理的开户许可证复印件→税务登记证备案办理结束
常用稳压管型号参数对照
常用稳压管型号参数对照 3V到51V 1W稳压管型号对照表1N4727 3V0 1N4728 3V3 1N4729 3V6 1N4730 3V9 1N4731 4V3 1N4732 4V7 1N4733 5V1 1N4734 5V6 1N4735 6V2 1N4736 6V8 1N4737 7V5
1N4739 9V1 1N4740 10V 1N4741 11V 1N4742 12V 1N4743 13V 1N4744 15V 1N4745 16V 1N4746 18V 1N4747 20V 1N4748 22V 1N4749 24V 1N4750 27V 1N4751 30V
1N4753 36V 1N4754 39V 1N4755 43V 1N4756 47V 1N4757 51V 摩托罗拉IN47系列1W稳压管IN4728 3.3v IN4729 3.6v IN4730 3.9v IN4731 4.3 IN4732 4.7 IN4733 5.1
IN4735 6.2 IN4736 6.8 IN4737 7.5 IN4738 8.2 IN4739 9.1 IN4740 10 IN4741 11 IN4742 12 IN4743 13 IN4744 15 IN4745 16 IN4746 18 IN4747 20
IN4749 24 IN4750 27 IN4751 30 IN4752 33 IN4753 34 IN4754 35 IN4755 36 IN4756 47 IN4757 51 摩托罗拉IN52系列 0.5w精密稳压管IN5226 3.3v IN5227 3.6v
(完整版)剑桥小学英语Joinin六年级复习题(二)2-3单元.doc
2011-2012 学年度上学期六年级复习题（Unit2-Unit3 ） 一、听力部分 1、听录音排序 ( ) () ()() () 2、听录音，找出与你所听到的单词属同一类的单词 （） 1. A. spaceman B. pond C . tiger （） 2. A.mascots B. potato C . jeans （） 3. A. door B. behind C . golden （） 4. A. sometimes B. shop C . prince （） 5. A. chair B. who C . sell 3、听录音，将下面人物与他的梦连线 Sarah Tim Juliet Jenny Peter 4、听短文，请在属于Mr. Brown的物品下面打√ ( ) ( ) ( ) ( ) ( ) ( ) ( ) 5、听问句选答句 （） 1. A. Yes, I am B. Yes, I have C . Yes, you do （） 2. A.Pink B. A friendship band C . Yes. （） 3. A. OK B. Bye-bye. C . Thanks, too. （） 4. A. Monday. B. Some juice. C . Kitty. （） 5. A. I ’ve got a shookbag. B. I ’m a student. C . It has got a round face. 6、听短文，选择正确答案 （） 1. Where is Xiaoqing from? She is from . A.Hebei B. Hubei C . Hunan （） 2. She goes to school at . A.7:00 B.7:30 C . 7:15 （） 3. How many classes in the afternoon? classes. A. four B. three C . two （） 4. Where is Xiaoqing at twelve o ’clock? She is . A. at home B. at school C .in the park （） 5. What does she do from seven to half past eight? She . A.watches TV B. reads the book C. does homework
很全的二极管参数
G ENERAL PURPOSE RECTIFIERS – P LASTIC P ASSIVATED J UNCTION 1.0 M1 M2 M3 M4 M5 M6 M7 SMA/DO-214AC G ENERAL PURPOSE RECTIFIERS – G LASS P ASSIVATED J UNCTION S M 1.0 GS1A GS1B GS1D GS1G GS1J GS1K GS1M SMA/DO-214AC 1.0 S1A S1B S1D S1G S1J S1K S1M SMB/DO-214AA 2.0 S2A S2B S2D S2G S2J S2K S2M SMB/DO-214AA 3.0 S3A S3B S3D S3G S3J S3K S3M SMC/DO-214AB F AST RECOVERY RECTIFIERS – P LASTIC P ASSIVATED J UNCTION MERITEK ELECTRONICS CORPORATION
U LTRA FAST RECOVERY RECTIFIERS – G LASS P ASSIVATED J UNCTION
S CHOTTKY B ARRIER R ECTIFIERS
S WITCHING D IODES Power Dissipation Max Avg Rectified Current Peak Reverse Voltage Continuous Reverse Current Forward Voltage Reverse Recovery Time Package Part Number P a (mW) I o (mA) V RRM (V) I R @ V R (V) V F @ I F (mA) t rr (ns) Bulk Reel Outline 200mW 1N4148WS 200 150 100 2500 @ 75 1.0 @ 50 4 5000 SOD-323 1N4448WS 200 150 100 2500 @ 7 5 0.72/1.0 @ 5.0/100 4 5000 SOD-323 BAV16WS 200 250 100 1000 @ 7 5 0.8 6 @ 10 6 5000 SOD-323 BAV19WS 200 250 120 100 @ 100 1.0 @ 100 50 5000 SOD-323 BAV20WS 200 250 200 100 @ 150 1.0 @ 100 50 5000 SOD-323 BAV21WS 200 250 250 100 @ 200 1.0 @ 100 50 5000 SOD-323 MMBD4148W 200 150 100 2500 @ 75 1.0 @ 50 4 3000 SOT-323-1 MMBD4448W 200 150 100 2500 @ 7 5 0.72/1.0 @ 5.0/100 4 3000 SOT-323-1 BAS16W 200 250 100 1000 @ 7 5 0.8 6 @ 10 6 3000 SOT-323-1 BAS19W 200 250 120 100 @ 100 1.0 @ 100 50 3000 SOT-323-1 BAS20W 200 250 200 100 @ 150 1.0 @ 100 50 3000 SOT-323-1 BAS21W 200 250 250 100 @ 200 1.0 @ 100 50 3000 SOT-323-1 BAW56W 200 150 100 2500 @ 75 1.0 @ 50 4 3000 SOT-323-2 BAV70W 200 150 100 2500 @ 75 1.0 @ 50 4 3000 SOT-323-3 BAV99W 200 150 100 2500 @ 75 1.0 @ 50 4 3000 SOT-323-4 BAL99W 200 150 100 2500 @ 75 1.0 @ 50 4 3000 SOT-323- 5 350mW MMBD4148 350 200 100 5000 @ 75 1.0 @ 10 4 3000 SOT-23-1 MMBD4448 350 200 100 5000 @ 75 1.0 @ 10 4 3000 SOT-23-1 BAS16 350 200 100 1000 @ 75 1.0 @ 50 6 3000 SOT-23-1 BAS19 350 200 120 100 @ 120 1.0 @ 100 50 3000 SOT-23-1 BAS20 350 200 200 100 @ 150 1.0 @ 100 50 3000 SOT-23-1 BAS21 350 200 250 100 @ 200 1.0 @ 100 50 3000 SOT-23-1 BAW56 350 200 100 2500 @ 70 1.0 @ 50 4 3000 SOT-23-2 BAV70 350 200 100 5000 @ 70 1.0 @ 50 4 3000 SOT-23-3 BAV99 350 200 100 2500 @ 70 1.0 @ 50 4 3000 SOT-23-4 BAL99 350 200 100 2500 @ 70 1.0 @ 50 4 3000 SOT-23-5 BAV16W 350 200 100 1000 @ 75 0.86 @ 10 6 3000 SOD-123 410-500mW BAV19W 410 200 120 100 @ 100 1.0 @ 100 50 3000 SOD-123 BAV20W 410 200 200 100 @ 150 1.0 @ 100 50 3000 SOD-123 BAV21W 410 200 250 100 @ 200 1.0 @ 100 50 3000 SOD-123 1N4148W 410 150 100 2500 @ 75 1.0 @ 50 4 3000 SOD-123 1N4150W 410 200 50 100 @ 50 0.72/1.0 @ 5.0/100 4 3000 SOD-123 1N4448W 500 150 100 2500 @ 7 5 1.0 @ 200 4 3000 SOD-123 1N4151W 500 150 75 50 @ 50 1.0 @ 10 2 3000 SOD-123 1N914 500 200 100 25 @ 20 1.0 @ 10 4 1000 10000 DO-35 1N4148 500 200 100 25 @ 20 1.0 @ 10 4 1000 10000 DO-35 LL4148 500 150 100 25 @ 20 1.0 @ 10 4 2500 Mini-Melf SOT23-1 SOT23-2 SOT23-3 SOT23-4 SOT23-5 SOT323-1 SOT323-2 SOT323-3 SOT323-4 SOT323-5