aoac-method verification
How to Meet
ISO 17025
Requirements for
Method Verification
Prepared by:
AOAC INTERNATIONAL
481 N. Frederick Ave, Suite 500
Gaithersburg, MD 20877, USA
https://www.sodocs.net/doc/1b15515065.html,
Acknowledgments
At the request of the AOAC Technical Division for Laboratory Management (TDLM), the Analytical Laboratory Accreditation Criteria Committee (ALACC) prepared this guide in an effort to provide guidance to laboratory managers by clarifying the activities needed to verify that a laboratory can perform a method successfully. Experts from various groups representing different sectors of the analytical community drafted and reviewed the guide. The guide shows the consensus of a diverse group of stakeholders, including accreditation bodies, laboratories, auditors, statisticians, and p harmaceutical and feed industries. European viewpoints are also represented.
The guide was written under the leadership of:
M.L. JANE WEITZEL, Watson Pharmaceuticals, USA, Chair of ALACC ALACC sub-chairs:
SUZANNE M. LEE, General Mills, USA, Chair of the Chemistry Subcommittee MICHELE SMOOT, Silliker Laboratories Group, USA, Chair of the Microbiology Subcommittee
NUBIA VIAFARA, Cangene Corp., Canada, Chair of the Pharmaceutical Subcommittee
In addition, MICHAEL BRODSKY, Brodsky Consultants, Canada, contributed the microbiology section.
PURPOSE
The purpose of the guide is to define the activities that are required to fulfill method verification based on analytical method performance characteristics.
ISO 17025:2005 section 5.4.2 states:
“…The laboratory shall confirm that it can properly operate standard methods before introducing the tests or calibrations. If the standard method changes, the confirmation shall be repeated.”
In this guide, to confirm is the same as to verify.
Verification that a laboratory can adequately operate a standard method requires that the laboratory provide objective evidence the performance parameters specified in the test method have been met with the matrices to which the method is being applied. Most often, the critical requirements are the accuracy and the precision (generally accepted as repeatability and reproducibility) which are reflected in the measurement uncertainty. The objective evidence is the accuracy and precision obtained from actual lab data.
SCOPE AND APPROACH
The scope of this guide encompasses AOAC Official Methods SM, EPA, FDA and FSIS official methods, and NADA methods and methods used in Microbiological, Food and Pharmaceutical labs.
Different industries may have differing terminology when describing categories of analytical methods and analytical parameters. This guide attempts to use the terminology commonly used by AOAC.
Different industries may have specific requirements. A particular federal agency or client may have very specific criteria for method verification. In this case the client’s or agency’s requirements would override those in this guide.
The analytical test methods are grouped according to the category of method based on its purpose. The lab can identify the category of test method it is verifying and find the corresponding parameters that need to be verified.
When a method is verified, the laboratory is required to demonstrate that it can achieve certain specific p erformance characteristics/p arameters established during the validation study. The validation study must contain all pertinent performance characteristics. Certain performance characteristics, such as linearity, will not vary from lab to lab and do not need to be verified. Other parameters, such as repeatability, are specific to the lab performing the method and need to be verified. Thus, the performance characteristics that need to be verified are a subset of the performance characteristics included in a method validation.
This guide treats chemical test methods and microbiology methods separately.
CHEMICAL METHODS
Categories of Chemical Methods
Chemical analytical methods fulfill many different p urp oses, from quantifying an analyte at a low concentration to identifying a material. With such a variety of methods, it is logical that different test methods require varying verification. For ease of discussion, the test methods can be divided into six different categories
based on their purpose. The categories are listed below. For each of the categories of test methods only relevant performance characteristics need to be included in a method verification. The approach of this guide is to list all p erformance characteristics needed for verification, and exp lain the reason for verifying the p erformance characteristic.
The six categories of chemical analytical methods are:
1. Confirmation of Identity, a method that ensures a material is what it purports to be or confirms the
detection of the target analyte.
2. Quantifying an analyte at a low concentration.
3. Determining if an analyte is present above or below a specified, low concentration (often called a Limit
Test). The specified concentration is close to the LOQ.
4. Quantifying an analyte at a high concentration.
5. Determining if an analyte is present above or below a specified, high concentration (often called a Limit
Test). The specified concentration is substantially above the LOQ.
6. Qualitative test.
Since the activities needed for method verification are a subset of those needed for validation, the required performance characteristics for validation will be presented first. The performance characteristics needed for the validation of each of six main categories of chemical test methods are identified in Table 1. If a performance characteristic is not needed for validation, it is not needed for verification. In Table 1, “Yes” means the performance characteristic must be included for validation and “No” means the performance characteristic does not need to be included for validation.
Requirements of Method Verification for the Six Categories of Chemical Test Methods (Tables 2–6) In Tables 2–5, “Yes” means the performance characteristic must be included for verification and “No” means the performance characteristic does not need to be included for verification.
Table 1. Categories of Chemical Test Methods: Since the activities needed for method verification are a subset of those needed for validation, the required performance characteristics for validation are presented in this table
Performance Characteristic
Performance Characteristics Included in a Validation
Identification 1
Analyte at Low
Concentration
Quantitative 2
Analyte at Low
Concentration
Limit Test 3
Analyte at
High
Concentration
Quantitative 4
Analyte at
High
Concentration
Limit Test 5Qualitative 6
Accuracy No Yes No Yes Yes No Precision No Yes No Yes Yes No Specificity Yes Yes Yes Yes Yes Yes LOD No Yes Yes Yes/No No No LOQ No Yes No Yes/No No No Ruggedness No Yes No Yes No No Linearity/Range No Yes No Yes No No
Table 2. Category 1: Confirmation of Identity—A method that ensures a material is what it purports to be or confirms the detection of the target analyte
Performance
Characteristic Verification Verification Activities Reason for Verification
Specificity No—if the lab’s samples are
identical to those in the
standard method and if any
differences in instrumentation
do not impact specificity.NA If the samples have the same
matrix, the specificity which is
based on basic principles, will
not be impacted. Basic
principles are chemical
reactions, e.g. reaction of Ag
with Cl to create a precipitate.
Yes—if the lab’s samples differ from those in the standard
method.Same as those required for
validation.
Yes–if differences between instruments could affect
specificity. The activity need only deal with
the unique aspect’s of the lab’s
samples or instrumentation.
Specificity can be impacted by
differences in instrumentation.
Table 3. Category 2: Analyte at Low Concentration, Quantitative
Performance
Characteristic Verification Verification Activity Reason for Verification
Accuracy Yes If the concentration range for which the
method is validated is narrow (<1 order
of magnitude), analyze one reference
material/standard/spike at one
concentration. Otherwise, demonstrate
accuracy at each concentration level
(low, middle and high) by analyzing one
reference material/standard/spike at each
level.Over a narrow concentration range, the accuracy and precision should not vary, therefore, the demonstration at one concentration is sufficient. Over a wide concentration range, the accuracy and precision can vary, thus they need to be verified at the different concentration
levels.
Precision Yes Perform the repeatability test once. If the
method covers a concentration range >1
order of magnitude, then the repeatability
test must include low, middle and high
concentrations.Over a narrow concentration range, the accuracy and precision should not vary, therefore, the demonstration at one concentration is sufficient. Over a wide concentration range, the accuracy and precision can vary, thus they need to be verified at the different concentration levels. Intermediate precision, between analysts, is handled by making sure the analysts are trained and can adequately perform the method.
Specificity No/Yes See Specificity in General Requirements See Specificity in General Requirements LOD Yes Run a sample close to LOD LOD is very likely to be matrix and
instrument specific
LOQ Yes Run a sample close to LOQ LOQ is very likely to be matrix and
instrument specific
Table 4. Category 3: Analyte is present above or below a specified, low concentration (Limit Test) Performance
Characteristic Verification Verification Activity Reason for Verification
LOD Yes Run a sample close to LOD LOD is very likely to be matrix and
instrument specific
LOQ Yes Run a sample close to LOQ LOQ is very likely to be matrix and
instrument specific Specificity No/Yes See Specificity in General
Requirements
See Specificity in General Requirements
Table 5. Category 4: Quantifying an analyte at high concentration and Category 5: Analyte above or below a specified, high concentration (often called a Limit Test)
Performance
Characteristic Verification Verification Activity Reason for Verification
Accuracy Yes If the method is a limit test or if the
concentration range for which the
method is validated is narrow (<1 order
of magnitude), analyze one reference
material/standard/spike at one
concentration. Otherwise, demonstrate
accuracy at each concentration level,
low middle and high by analyzing one
reference material/standard/spike at
each level.Over a narrow concentration range, the accuracy and precision should not vary, therefore, the demonstration at one concentration is sufficient. Over a wide concentration range, the accuracy and precision can vary, thus they need to be verified at the different concentration
levels.
Precision Yes Perform the repeatability test once. If the
method covers a concentration range >1
order of magnitude, then the
repeatability test must include low,
middle and high concentrations.Over a narrow concentration range, the accuracy and precision should not vary, therefore, the demonstration at one concentration is sufficient. Over a wide concentration range, the accuracy and precision can , thus they need to be verified at the different concentration levels. Intermediate precision, between analyst, is handled by making sure the analysts are trained and can adequately perform the method.
Specificity No/Yes See Specificity in General Requirements See Specificity in General Requirements
Table 6. Category 6: Qualitative Tests
Qualitative tests are used to identify a specific element or compound (analyte) based on the response of a material to the test. The most important characteristic of a qualitative test is its ability to reliably identify the analyte in the presence of other substances. This is referred to as the “specificity.”
Method validation includes determining any cross reactivity with other known entities. The lack of cross reactivity demonstrates the specificity of the method. If samples are identical to those for which the method is intended, no verification of specificity is required. If any matrix components are unique to the lab’s samples, the lab will need to demonstrate there is no impact on specificity.
The method precision of qualitative tests is generally expressed as false-positive/false-negative rates and is determined at several concentration levels. Verification of a lab’s ability to properly operate a qualitative method can be demonstrated by analyzing populations of negative and positive fortified samples. For example, for each different sample matrix, duplicate samples are analyzed at three levels. Suggested levels are blanks (no analyte), low level (near the lower range of the method) and high level (near the high end of the range). Standard additions can be used to obtain the correct concentration levels. Rates comparable to those stated in the validated method demonstrate the labs ability to operate the method.
USING MEASUREMENT UNCERTAINTY IN METHOD VERIFICATION OF CHEMICAL TESTS The estimate of measurement uncertainty (MU) for a measurand is the indicator of precision, and the MU is one of the components that can be used to verify a lab can perform the method satisfactorily.
When there is no validation data available, the MU may be the only parameter that can be compared to the specification to ensure the method works.
The comp arison of a lab’s p erformance (bias and p recision) can be comp ared to those from the collaborative study using the approach as described in ISO Technical Specification ISO/TS 21748, Guidance for the use of repeatability, reproducibility and trueness estimates in measurement uncertainty estimation.
Additional guidance, including examples of using the approach suggested in ISO/TS 21748 will be posted on the AOAC Website.
MICROBIOLOGICAL METHODS
The performance characteristics needed for the validation and verification of each of three main categories of microbiological test methods are identified in Table 7.
Verification Guidelines
Verification of microbiological methods also requires that the following parameters are addressed:
1. Laboratory competency of achieving method performance characteristics on an on-going basis.
2. Analyst performance: Can your analysts perform the method with the equivalent degree of precision and
accuracy?
Table 7. Categories of Microbiological Test Methods: Performance Characteristics Included in a Validation Study
Performance
Characteristic Identification Quantitative Qualitative (P/A)
Verification (where applicable)
Relative Accuracy Yes Yes No No Matrix Effects No Yes Yes Yes Precision No Yes No Yes Selectivity No Yes Yes No Specificity Yes Yes Yes No Inclusivity Yes Yes Yes No Exclusivity Yes Yes Yes No False-Positive Rate No Yes Yes No False-Negative Rate No Yes Yes No LOD No Yes Yes No LOQ No Yes No No Ruggedness Yes Yes Yes No Linearity/Range No Yes No No
Measurement Uncertainty for Microbiology
Measurement uncertainty is a parameter associated with the result of a measurement that characterizes the dispersion of the values that could reasonably be attributed to the measurand, in other words, the variance or standard deviation of the result or the degree of confidence in an analytical result. Calculation of MU is more reliable with a minimum of 30 observations in order to obtain the 95% confidence limits of the overall precision of the method. Therefore it is not unreasonable to expect that each of the required performance characteristics would also be based on 30 observations. MU usually requires the inclusion of repeatability and reproducibility of all factors that contribute to >10% of the variability and uses the root sum of squares in the calculation, e.g. where there are 2 key factors (Uc) = ? RSD12 + RSD22. In its simplest determination, however relativeMU or RelativeUe = 2 ′ RSD R (Relative Standard Deviation of Reproducibility) when all factors that could impact on the reliability of a result are taken into consideration.
In this regard, Validation data can be used comparatively for method verification since the validation study provides reference values for RSD R and RSD r (Relative Standard Deviation of Reproducibility and Relative Standard Deviation of Repeatability).
For example a validation study of Pour Plate counting obtained the following data:
RSD r￡ 7.7% (0.077) (within analysts)
RSD R￡ 18.2% (0.182) (between analysts)
Calculation of combined uncertainty for counting:
Sum of squares: (0.077)2 + (0.182)2 = 0.0371
Combined relative uncertainty = ?(0.0371) = 0.193 = 19.3%
Expanded relative uncertainty for counting: (Use coverage factor k = 2 for 95% confidence)
= 2 ′ 19.3% = 38.6%
The MU for this technique is 38.6% and becomes the reference value for the MU determined by in-house method verification.
Experimental data for calculating MU can be obtained from:
?Proficiency testing (PT) programs
?Reference samples
?Spike recovery
?Method verification replicates
?Sample duplicates
Additional information on estimating Measurement Uncertainty for microbiological methods can be found in the American Association for Laboratory Accreditation in the Guideline “G108—Guidelines for Estimating Uncertainty for Microbiological Counting Methods.”
Analyst Performance in Microbiology
Only analysts who have been adequately trained to p erform a method should p articip ate in method verification. Training and qualification of analysts require a written protocol of activities with documented results of achievement. Trained analysts need to be assessed on an on-going basis.
Assessment tools may include:
?Blind samples (known positive and known negative samples)
?Observation of performance
?Written test; e.g. on Quality Control Practices, calculations, interpretation of results, knowledge of
quality policies and procedures
?Daily checks on precision of duplicate counts*
?Proficiency testing**
*Precision of Duplicate Counts:
1. All analysts perform duplicate counts on 315–30 samples for each type of matrix, record as D1 and D2
2. Convert data to Log10
3. Determine the absolute value of the range and its log (R log) for each pair (D1 – D2)
4. Calculate the mean ì for each set of data
ì =
R
n
log ?
5. Analysts can now run daily duplicates
6. 99% Precision criteria: R ￡ 3.27 ì
7. Plot results on a control chart to monitor variability
Ref. SMEWW. 1998. 20th ed. (9–11)
**Proficiency Testing
1. Intralaboratory Proficiency Testing:
Internally controlled “check sample” or spiked samples” used as:
?An ongoing assessment of analytical performance and competency by individual analysts within a
laboratory
? A means to demonstrate competence for tests not covered by external proficiency programs
?To detect training needs
2. Interlaboratory Proficiency Testing
Proficiency panels from outside source; e.g. AOAC, FDA
(a) Provides a measure of precision and relative accuracy of analytical methods performed by different
laboratories
(b) Provides an estimate of the relative accuracy and precision of results between laboratories
(c) Can be used for intralaboratory proficiency testing, but by itself is not designed for assessment of the
competency of individual analysts
GENERAL REQUIREMENTS (for chemical and microbiological methods)
The lab must have a management system consistent with that described in ISO/IEC 17025:2005.
The analysts must be adequately trained:
?The analyst must have the appropriate knowledge, experience, and training to perform the procedure.
?The analyst must be competent in performing the given functions of the lab:
–operating the instrumentation
–performing the analysis as specified
–understanding the analytical technique
?The training must be documented.
The verification exercise must be planned, approved, and documented and a final report kept on file to demonstrate the lab can perform the method adequately.
Verification documentation should be created that:
?Describes the procedure to be verified
?Details the analytical performance characteristics to be evaluated
?Establishes acceptance criteria used to determine that the procedure performs suitably
?Justifies deviations from Reference Method
General Requirements—Specificity
For specificity in all categories of methods, if samples are identical to those for which the method is intended and validated, and the method is based on basic principles then no verification is needed. If the samples have the same matrix, the specificity which is based on basic principles, will not be impacted. Basic principles are chemical reactions, e.g. reaction of Ag with Cl to create a precipitate. For some methods, the specificity can be affected by the instrument used. In these cases the lab should assess if the instrument differences could affect the specificity, and if so, include specificity in the verification, e.g. the different resolution and/or detection systems in inductively coup led p lasma op tical emission sp ectrop hotometers may result in different interferences.
METHOD SELECTION “FIT FOR USE”
Analytical methods are evaluated based on attributes such as accuracy, precision, specificity, sensitivity, detectability and practicality. Compromise between attributes is inherent in the selection of methods. However, any method selected for use must be appropriate to the requirements of the regulatory function and must be within the capabilities of the laboratory staff. Depending on the documentation available on a method, varying degrees of method verification or validation are recommended before it is adopted for routine use.
The lab must first ensure the chosen method is applicable to the samples the lab will be analyzing with the method. If there is any difference between the lab’s samples and those for which the method is validated, the extent of the difference and its impact must be assessed. The impact of the difference could require a partial validation to include the performance characteristics that are impacted or the method may require complete validation.
CIRCUMSTANTIAL CHANGES/DEVIATIONS FROM THE METHOD AS VALIDATED For a number of reasons, a lab may not be able to perform the method exactly as validated. In these circumstances, the method verification may have to deal with these differences. A number of unforeseen scenarios are shown in Table 8. If a scenario does occur the listed equivalency study shall be performed. There may be other scenarios; this list is not all inclusive.
Table 8.
Parameter in Validated Method Difference from Validated Method Required Equivalence Study
a. Apparatus and equipment used a. Either some of the apparatus and
equipment are outdated or the lab
does not have them, and the lab
wants to use available apparatus and
equipment An instrument equivalence bridging study is needed to ensure that the “numbers” generated by alternate apparatus and equipment relate in some reproducible way to the concentrations determined in the
validated method.
b. Specific detector b. The lab may not have the specific
detector and the lab would like to use
one that is available.
b. An equivalence study is needed comparing the “numbers” obtained between the two detectors to ensure that the “numbers” generated relate in some reproducible way to the concentrations determined in the
validated method.
c. Sample preparation: Occasionally samples are prepared in liquid nitrogen to prevent loss of analyte(s)
c. If the lab has production type
environment, it can process sample
quickly at room temperature.
c. A bridging study comparing the two
sample preparations is needed to
ensure that the “numbers” generated
relate in some reproducible way to the
concentrations determined in the
validated method.
d. Other possible scenarios:
i. Columns and cartridges ii. Mobile phase
iii. Mobile phase gradient iv. Throughput
i. The lab wishes to use available
columns and cartridges of different
vendors.
ii. Occasionally mobile phase used in
the validated method is found to be
corrosive and detrimental to pump and
seals. In this case a compatible
substitute can be used.
iii. The lab may not have the required
3-pump gradient system; solvents are
pre-mixed for two-pump gradient.
iv. Subtle modifications in extraction
and purification steps may be needed
such as exchange of extraction
solvent of less health hazard solvent,
shaking vs. vortexing, use of
compatible solvent, use of SPE
cartridges of different vendor(s), etc.
d. Any of the scenarios mentioned in
column 2 require bridging to ensure
that the “numbers” generated relate in
some reproducible way to the
concentrations in the validated
method.
PHARMACEUTICAL
To prevent confusion, the use of the term Identity in the pharmaceutical industry is explained here.
In the pharmaceutical industry, identity tests are intended to ensure the identity of an analyte in a sample. Identity—is the material what it is supposed to be?
In other analytical fields Identity has a different meaning, e.g. in the Eurachem definition. “It is necessary to establish that the signal produced at the measurement stage, or other measured property, which has been attributed to the analyte, is only due to the analyte and not from the presence of something chemically or physically similar or arising as a coincidence. This is confirmation of identity.” Analytical Methods A Laboratory Guide to Method Validation and Related Topics, p. 14
Thus in the pharmaceutical industry the term Identity describes a “category of analytical test” while in the Eurachem guide Identity describes an analytical parameter.
FOOD
Chemical Testing Category 3: Method determining if an analyte is present above or below a specified, low concentration (often called a Limit Test).
This category is pretty delicate as it is located at the interface of quantitative–qualitative determinations. However, for food safety it represents a very important category, i.e. residues of banned vet drug, which must not be present in food of animal origin. In the EU this is covered by Decision 657/2002/EC. In the EU much more emphasis is placed on the validation of such methods in comparison to those included in this guide. DEFINITIONS
Accuracy
For the purposes of this document, the term accuracy is defined as:
The closeness of agreement between the measured value and the accepted, “true,” or reference value.
Accuracy is indicative of the bias of the measurement process. Accuracy is often evaluated by repetitively spiking the matrix or placebo with known levels of analyte standards at or near target values. The fraction or percentage of added analyte recovered from a blank matrix is often used as the index of accuracy. Added analyte, however, may not always reflect the condition of the natural analyte in the materials submitted for analysis. (Official Methods of Analysis of AOAC INTERNATIONAL, 18th Ed., Appendix E).
This guide acknowledges that the Official Methods of Analysis (OMA) definition of “accuracy” is not fully in line with the current version of the VIM-3rd edition which defines in clause
2.13 (
3.5)
measurement accuracy
accuracy of measurement
accuracy
closeness of agreement between a measured quantity value and a true quantity value of a measurand NOTES
1. The concept ‘measurement accuracy’ is not a quantity and is not given a numerical quantity value. A
measurement is said to be more accurate when it offers a smaller measurement error.
2. The term “measurement accuracy” should not be used for measurement trueness and the term
measurement precision should not be used for ‘measurement accuracy,’ which, however, is related to both these concepts.
3. ‘Measurement accuracy’ is sometimes understood as closeness of agreement between measured
quantity values that are being attributed to the measurand.
Intermediate Precision
Intermediate precision: The precision of an analytical procedure expresses the closeness of agreement between a series of measurements obtained from multiple sampling of the same homogeneous sample under the p rescribed conditions. Intermediate p recision exp resses within-laboratories variations: different days, different analysts, different equipment, etc. (ICH Validation of Analytical Procedures: Text and Methodology, Q2R).
Intermediate precision: Measurement precision under a set of conditions of measurement. (ISO/DGuide 99999.2, International vocabulary of basic and general terms in metrology (VIM). Third edition, 2.24 without notes.)
Repeatability
Repeatability (of results of measurements): Closeness of the agreement between the results of successive measurements of the same measurand carried out subject to all of the following conditions:?same measurement procedure
?same observer
?same measuring instrument, used under the same conditions
?same location
?repetition over a short period of time
(ISO Guide 30: 1992 A7)
Repeatability
Measurement precision under the set of repeatability conditions of measurement. (ISO/DGuide 99999.2, International vocabulary of basic and general terms in metrology (VIM). Third edition, 2.22)
Reproducibility
Rep roducibility (of results of measurements): Closeness of the agreement between the results of measurements of the same measurand, where the measurements are carried out under changed conditions such as:
?principle or method measurement
?observer
?measuring instrument
?location
?conditions of use
?time
(ISO Guide 30:1992 A.8)
Note: For the purposes of this ALACC guide a change to the principle of measurement would create a new method that would have to be validated.
Reproducibility
Measurement p recision under rep roducibility conditions of measurement. (ISO/DGuide 99999.2, International vocabulary of basic and general terms in metrology (VIM). Third edition, 2.26 without notes.)
Standard Method
A method that has been validated by an authoritative body. Most food and pharmaceutical methods are found in AOAC, USDA, FDA, EPA, AOCS, AACC, ISO, IUPAC, USP, and FCC method manuals. Many trade associations p ublish their own methods and p rovide useful resources. A few examp les include the Corn Refiners Association, National Food Processors Association, Association for Dressings and Sauces, and the American Spice Trade Association.
Validated Method
The planned and documented procedure to establish the method’s performance characteristics. The performance characteristics or the validation parameters of the method determine the suitability for its intended use. They define what the method can do under optimized conditions of matrix solution, analyte isolation, instrumental settings, and other experimental features. The inclusion of particular validation parameters in a validation protocol depends on the application, the test samples, the goal of the method,
and domestic or international guidelines or regulations, as applicable. (Official Methods of Analysis of AOAC INTERNATIONAL, 18th Ed., Appendix E)
Comments:
?Validation of a method establishes, by systematic laboratory studies that the method is fit-for-purpose,
i.e., its performance characteristics are capable of producing results in line with the needs of the
analytical problem. The important performance characteristics include: selectivity and specificity
(description of the measurand), measurement range, calibration and traceability, bias linearity, limit of detection/limit of quantitation, ruggedness, and precision. The above characteristics are interrelated.
Many of these contribute to the overall measurement uncertainty and the data generated may be used to evaluate the measurement uncertainty. The extent of validation must be clearly stated in the
documented method so that users can assess the suitability of the method for their particular needs.
?Examples of validated methods can be obtained from specific organizations such as AOAC
INTERNATIONAL.
Verification
Provision of objective evidence that a given item fulfils specified requirements.
EXAMPLES
(a) Confirmation that a given reference material as claimed is homogeneous for the quantity value and
measurement procedure concerned, down to a measurement portion having a mass of 10 mg.
(b) Confirmation that performance properties or legal requirements of a measuring system are achieved.
(c) Confirmation that a target measurement uncertainty can be met.
NOTES
1. When applicable, measurement uncertainty should be taken into consideration.
2. The item may be, e.g., a process, measurement procedure, material, compound, or measuring system.
3. The specified requirements may be, e.g., that a manufacturer’s specifications are met.
4. Verification in legal metrology, as defined in VIML [10], and in conformity assessment in general, pertains
to the examination and marking and/or issuing of a verification certificate for a measuring system.
5. Verification should not be confused with calibration. Not any verification is a validation.
6. In chemistry, verification of identity of entity involved, or of activity, requires a description of the structure
or properties of that entity or activity.
VIM 3, 2.44
Verification
Confirmation, through the provision of objective evidence, that specified requirements have been fulfilled (ISO 9000:2000 3.8.4 without notes).
Comment:
?In connection with the management of measuring equipment, verification provides a means for
checking that the deviations between values indicated by a measuring instrument and corresponding known values of a measured quantity are consistently smaller than the maximum allowable error
defined in a standard, regulation, or specification peculiar to the management of the measuring
equipment. The result of verification leads to a decision either to restore in service, perform
adjustments, or repair, or to downgrade, or to declare obsolete. In all cases it is required that a written trace of the verification performed shall be kept on the measuring instrument’s individual record.
建筑行业通用英文缩写及含义
建筑行业通用英文缩写及含义
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常用的英语缩写（AＢＢRＥVIATIOＮS) 构件篇 英语缩写中文翻译COLUMN 柱子 POST 从梁上升起的柱子BAＳＥPLATE 底板 CAP PLATE 顶板 CＯVER PLＡTＥ盖板 ＥND PLATE 封板,短板 SEAL PＬAＴE 封板 SHEAR ＰLＡＴE 剪切板 COＮＮECTＩON PLATE 连接板 GIRＤER 主梁 ＢEAM 梁/次梁 ＳECONDARY BEAM 次梁 JOIＳT GIRDEＲ主桁架 ＪＯISＴ次桁架 ＢＲＡCE 支撑 ＬIＮTＥＬ过梁 ＭISC 杂件 ＥＭBED PALTE 预埋板件 AＮCＨＯR BOLT 地脚螺栓 FRAMＥ钢架 RAＩLＩNＧ扶手 STAIR 楼梯 RC WALL 混凝土墙 BRＡCＫET 马仔 ＰAＲT/TＹP ＰARＴ零件 ASSY 组合件CANOPY 雨棚 CATWAＬK 猫道 LＡDDER 爬梯 ＰURLIＮ檩条 ＦISH PＬATE 结合板 HＯＩSＴＢＥAM 起吊运输梁 BUＩLＴ－ＵP ＳECTIＯN 组合截面 ＢEARINGＰLATE 支撑板 ＣANTIＬEVＥRＢEAＭ悬臂梁/挑梁 ＣRANE GIＲDER 吊车梁 CROSS BEAＭ井字梁
GＩRT 抗风梁 RINＧBＥＡＭ圈梁 DIAＰHRＡGM 横隔板 ＳTIFFENER／ＳTIFF 加劲板/肋 GＵＳＳＥT ＰＬAＴＥ节点板 HＡNGEＲ吊杆／吊环GRIＰ夹具／卡子ＴIE BAR 拉结钢筋 ＴIＥBEＡＭ系梁 TＩＥTOD 系杆 TＩＥROＤ系杆FLANGE 翼缘/法兰WEＢＰLATＥ/WＥB 腹板 图纸/版本篇 DＥSＩGN ＤRＡWINＧ设计图SHOP DRAＷING 施工图/详图FABRＩＣAＴION DRAWＩNＧ加工图 ARCＨITＥCTＵRＥ建筑图 ＡS-BUＩＬT DＲAWING 竣工图 FＯR APPRＯＶAL 审批 ＦOR FＡB加工UPDATE 更新 ＦOR FIELＤUSED 现场使用 材料篇 SHS(SＱUARE HOLLOW SECＴION）方通/方管RHS（RＥＣTＡNＧLE HOＬLOW ＳEＣＴIOＮ) 矩形管 CＨS(CIRCULAR ＨOＬLOW SＥＣＴIOＮ）圆管/喉管GMS( ＧAＬＶMILＤSTEEＬ) 低碳钢 RSC（RＯLLＥＤSTEEL CＨANＮＥL) 槽钢 RSA（ＲOLLEＤSTEEＬAMＧLＥ) 角钢 ＨSB （HIＧN STRENＧTH BOLＴ）高强螺栓 TS(TUBE CHＡNNEL）方通/方管HSＳ（HOＬLOW SQUＡRE SECTION) 方通/方管 EＡ(ＥQUＡL ANGLＥ) 等边角钢 UA（UNEQUＡL ＡNGLE）不等边角钢ＵC（UNIVERSAL COLUＭNS）等边工字钢UB（UＮIVＥＲSAL BＥAM）不等边工字钢PＦＣ(ＰＡRALLEL FＬANGE CHＡNNEL）方脚槽钢CSK BOＬT 沉头螺栓 FLＡT BAＲ扁钢 CＨANNEL 槽钢
质量管理体系中英文缩写与其解释
质量管理体系中英文缩写与其解释 Engineering 工程 / Process 工序（制程） Man, Machine, Method, Material, 人，机器，方法，物料，环境- 可能导 4M&1E Environment 致或造成问题的根本原因 AI Automatic Insertion 自动插机 ASSY Assembly 制品装配 ATE Automatic Test Equipment 自动测试设备 BL Baseline 参照点 BM Benchmark 参照点
BOM Bill of Material 生产产品所用的物料清单 C&ED/C Cause and Effect Diagram 原因和效果图 AED CA Corrective Action 解决问题所采取的措施 电脑辅助设计.用于制图和设计3维物体 CAD Computer-aided Design 的软件 对文件的要求进行评审，批准，和更改 CCB Change Control Board 的小组 依照短期和长期改善的重要性来做持续 CI Continuous Improvement 改善 COB Chip on Board 邦定-线焊芯片到PCB板的装配方法. CT Cycle Time 完成任务所须的时间 DFM
Design for Manufacturability 产品的设计对装配的适合性 设计失效模式与后果分析--在设计阶段 Design Failure Mode and Effect DFMEA 预测问题的发生的可能性并且对之采取 Analysis 措施 六西格玛(6-Sigma)设计 -- 设计阶段预 DFSS Design for Six Sigma 测问题的发生的可能性并且对之采取措施并提高设计对装配的适合性 DFT Design for Test 产品的设计对测试的适合性 实验设计-- 用于证明某种情况是真实DOE Design of Experiment 的 根据一百万件所生产的产品来计算不良DPPM Defective Part Per Million 品的标准 Design Verification / Design
所有船舶通用的英文缩写
第一部分 1 A/B Above Base Line 基准线以上 2 A/C Anticorrosive Paint 防腐涂料 3 A/F Antifouling Paint 防污漆 4 ABS American Bureau of Shipping 美国船级社 5 Abt Abt (About ) 大约,关于 6 ACCOM. Accommodation 船室,居住区 7 ACCM.L Accommodation Ladder 舷梯 8 ACCU Automatic control system certified for unattended eng. Room 无人机舱自动控制系统鉴定 9 AFRAMAX Average Freight Rate Assessment at the max. of Deadweight C.O.T 最大负载时平均运费率评估 10 A.P Bhd After Peak Bulkhead 船尖舱舱壁 11 ANSI American National Standards Institute 美国国家标准协会 12 AP After Perpendicular 艉垂线 13 API American Petroleum Institute 美国石油组织 14 APT After Peak Tank 尾尖舱 15 ARPA Automatic Rader Plotting Aids 自动雷达测图仪 16 ASTM American Society of Testing Materials 美国材料实验协会 17 B mld Moulded Breadth 型宽 18 B/C Bulk Carrier 散货船 19 B.L Base line 基线 20 Basic Design 基本设计 21 Ballast Control Room 压载控制室 22 BHP Brake Horse Power 制动马力 23 BOG Boil-off Gas 蒸发气体 24 BOM Bill of Material 材料清单 25 Bkt Bracket 支架,肘板 26 BHD Bulkhead 隔壁, 防水壁 27 C/H Cargo Hold 货舱 28 C.T Cable Trunk 电缆管道 29 CCI Class Comment Item 船级社说明项目
通用英文缩写解释
AH：外观颜色匹配工程师 APQP：产品质量先期策划 DRE：设计发布工程师 DTS：尺寸技术准备 ETR：工程试装要求 EWO：工程更改 FE：功能评估 GCA：全球顾客评审 GD&T：主要尺寸相关的零件、总成和整车的形位公差图纸，几何尺寸及公差图纸。 GM Global AAR---GM全球外观认可报告 GP4：生产件批准状况通知 GP5：供应商质量监控流程（GM1746） GP8：持续改进程序（GM1747） GP9：按节拍生产品（GM1960） GP10：供应商检测设备的评价和鉴定（GM1796） GP12：早期生产遏制（GM1920）IMDS：国际材料数据系统 MC：匹配 －MC0/1交样前，检具不能按时完成时，经过MC工程师批准，允许用三坐标进行代替测量。但测量时使用的基准必须与GD&T/Control Drawing一致，并得到SGM检具工程师的设计认可（A表），且基准的精度和重复性必须得到验证，符合要求。 －MC2检具必须经SGM检具工程师设计认可（A表）和制造认可（B表）。交样数量原则上MC0，MC1，MC2各5套
PATAC：泛亚汽车技术中心PCR：问题交流报告PDT：产品开发小组 PLP：主定位基准Pre-texture Instruction－Global Form ---GM全球皮纹认可报告PTR：供应商提供的零件必须是合格的，可用于正常的可销售车生产的零件。（所有新零件在作为正常零件供给SGM之前，均必须已成功地通过PTR的实施） S1：第一轮可销售车制造 SMT：系统管理小组 SVE：系统认证工程师 SQE：供应商质量工程师 SGE：外观皮纹工程师 TA：Technology assent:技术赞成（定点前的技术，能力方面的交流） TE：试验工程师 TVE：（动力总成）总认证工程师 VPM：整车性能经理 IV:工程认可（需要提供零件尺寸报告、材料试验报告、总成性能报告等所有试验报告）MC1/2：尺寸匹配（提交尺寸报告，合格率80%/90%） PVV：产品验证，小批量制造（尺寸报告，零件必须通过GP12） NS：非销售车制造（零件必须通过GP12-100%检验） S：销售车制造（零件通过PPAP人认可，零件必须通过GP12-100%检验） SORP：量产开始（具体数量根据订单，一般IV80套，MC10套，PVV几套到几十套不等。） GD&T：全球尺寸和公差标准 DPV: Defects per vehicle 每辆车缺陷数
质量体系中英文缩写与含义
质量管理体系中英文缩写与其解释Abbreviations and their explanations 缩写与其解释 Engineering 工程/ Process 工序（制程） 4M&1E Man, Machine, Method, Material, Environment 人，机器，方法，物料，环境- 可能导致或造成问题的根本原因 AI Automatic Insertion 自动插机 ASSY Assembly 制品装配 ATE Automatic Test Equipment 自动测试设备 BL Baseline 参照点 BM Benchmark 参照点 BOM Bill of Material 生产产品所用的物料清单 C&ED/CAED Cause and Effect Diagram 原因和效果图 CA Corrective Action 解决问题所采取的措施 CAD Computer-aided Design 电脑辅助设计.用于制图和设计3维物体的软件CCB Change Control Board 对文件的要求进行评审，批准，和更改的小组CI Continuous Improvement 依照短期和长期改善的重要性来做持续改善COB Chip on Board 邦定-线焊芯片到PCB板的装配方法. CT Cycle Time 完成任务所须的时间 DFM Design for Manufacturability 产品的设计对装配的适合性 DFMEA Design Failure Mode and Effect Analysis 设计失效模式与后果分析--在设计阶段预测问题的发生的可能性并且对之采取措施 DFSS Design for Six Sigma 六西格玛(6-Sigma)设计-- 设计阶段预测问题的发生的可能性并且对之采取措施并提高设计对装配的适合性 DFT Design for Test 产品的设计对测试的适合性 DOE Design of Experiment 实验设计-- 用于证明某种情况是真实的 DPPM Defective Part Per Million 根据一百万件所生产的产品来计算不良品的标准DV Design Verification / Design Validation 设计确认 ECN Engineering Change Notice 客户要求的工程更改或内部所发出的工程更改文件 ECO Engineering Change Order 客户要求的工程更改 ESD Electrostatic Discharge 静电发放-由两种不导电的物品一起摩擦而产生的静电可以破坏ICs和电子设备 FI Final Inspection 在生产线上或操作中由生产操作员对产品作最后检查 F/T Functional Test 测试产品的功能是否与所设计的一样 FA First Article / Failure Analysis 首件产品或首件样板/ 产品不良分析 FCT Functional Test 功能测试-检查产品的功能是否与所设计的一样FFF Fit Form Function 符合产品的装配，形状和外观及功能要求 FFT Final Functional Test 包装之前，在生产线上最后的功能测试 FMEA Failure Mode and Effect Analysis 失效模式与后果分析-- 预测问题的发生可能性并
通用英文缩写及含义
常用的英语缩写（ABBREVIATIONS）：构件篇 COLUMN 柱子 POST 从梁上升起的柱子 BASE PLATE 底板 CAP PLATE 顶板 COVER PLATE 盖板 END PLATE 封板，短板 SEAL PLATE 封板 SHEAR PLATE 剪切板 CONNECTION PLATE 连接板 BEAM 梁/次梁 SECONDARY BEAM 次梁 JOIST GIRDER 主桁架 GIRDER 主梁 JOIST 次桁架 BRACE 支撑 LINTEL 过梁 MISC 杂件 EMBED PALTE 预埋板件 ANCHOR BOLT 地脚螺栓 FRAME 钢架 RAILING 扶手 STAIR 楼梯 RC WALL 混凝土墙 BRACKET 马仔 PART/TYP PART 零件 ASSY 组合件 CANOPY 雨棚 CATWALK 猫道 LADDER 爬梯 PURLIN 檩条 FISH PLATE 结合板 HOIST BEAM 起吊运输梁 BUILT-UP SECTION 组合截面 BEARING PLATE 支撑板 CANTILEVER BEAM 悬臂梁/挑梁 CRANE GIRDER 吊车梁 CROSS BEAM 井字梁 GIRT 抗风梁 RING BEAM 圈梁 DIAPHRAGM 横隔板
STIFFENER/STIFF 加劲板/肋 GUSSET PLATE 节点板 HANGER 吊杆/吊环 GRIP 夹具/卡子 TIE BAR 拉结钢筋 TIE BEAM 系梁 TIE TOD 系杆 TIE ROD 系杆 FLANGE 翼缘/法兰 WEB PLATE/WEB 腹板 图纸/版本篇 DESIGN DRAWING 设计图 SHOP DRAWING 施工图/详图 FABRICATION DRAWING 加工图 ARCHITECTURE 建筑图 AS-BUILT DRAWING 竣工图 FOR APPROV AL 审批 FOR FAB 加工 UPDATE 更新 FOR FIELD USED 现场使用 材料篇 SHS 方通/方管SQUARE HOLLOW SECTION RHS 矩形管RECTANGLE HOLLOW SECTION CHS 圆管/喉管CIRCULAR HOLLOW SECTION GMS 低碳钢GALV MILD STEEL RSC 槽钢ROLLED STEEL CHANNEL RSA 角钢ROLLED STEEL AMGLE HSB 高强螺栓HIGN STRENGTH BOLT CSK BOLT 沉头螺栓 FLAT BAR 扁钢 CHANNEL 槽钢 TS 方通/方管TUBE CHANNEL HSS 方通/方管HOLLOW SQUARE SECTION ANGLE 角钢 TC BOLT 扛剪型螺栓 RB 混凝土 RIVET 铆钉 ROD 圆钢 PLATE 板材
lte各种英文缩写解释
<1>RAN 无线接入网 <2>RNC 无线网络控制器负责对基站进行整体管理, 包括对无线资源、本地移动用户和接入情况进行管理和控制，并对传输情况进行优化；RNC勺主要功能为无线资源管理，网络相关功能、无线资源控制（RRC的维护和运行,网管系统的接口等。RNC勺主要缺点为与空中接口相关的许多功能都在RNC中,导致资源分配和业务不能适配信道，协议结构过于复杂，不利于系统优化。 <3>HSDPA 高速下行链路分组接入，是一种移动通信协议，亦称为（3½；G）。该协议在WCDMA下行链路中提供分组数据业务，在一个5MHz载波上的传输速率可达8-10 Mbit/s （如 采用MIMO 技术，则可达20 Mbit/s ）。在具体实现中，采用了自适应调制和编码（AMC）、多输入多输出（MIMO ）、混合自动重传请求（HARQ）、快速调度、快速小区选择等技术。 <4>SGSN 服务支持节点负责管理分组交换数据流量的控制和管理。 <5>GGSN 网关支持节点负责与核心网的连接。GGSN 是本地网与外部分组交换网之间的网 关，因此也被称为GPRS路由器 <6>ACGW 核心接入网关AGW 接入网关 <7>RRC 无线资源控制子层 <8>RLC 无线链路控制 <9> PDU 协议数据单元 <10>ACK 确认应答 <11>FEC 前向纠错 <12>ACK命令正确应答 <13>OFDMA 正交频分多址 <14>OFDM 正交频分复用实际上OFDM 是MCM Multi-CarrierModulation ，多载波调制的一种。其主要思想是：将信道分成若干正交子信道，将高速数据信号转换成并行的低速子数据流，调制到在每个子信道上进行传输。正交信号可以通过在接收端采用相关技术来分开，这样可以减少子信道之间的相互干扰ICI 。每个子信道上的信号带宽小于信道的相关带宽，因此每个子信道上的可以看成平坦性衰落，从而可以消除符号间干扰。而且由于每个子信道的带宽仅仅是原信道带宽的一小部分，信道均衡变得相对容易 <15>SC-FDMA 单载波频分多址其特点为低峰均比，子载波间隔为15 kHz。 <16>CP 循环前缀 <17>TDD 时分双工FDD 频分双工 <18>LCR-TDD 低码速率时分双工 <19>HCR-TDD 高码速率时分双工 <20>采用小区间干扰控制技术的目。主要的多小区干扰补偿技术有: 干扰随机化技术、干扰 抵消技术和多小区干扰协调技术 <21>FDD下行频分双工3GPP LTE标准化的前期研究重点为下行频分双工（FDD）系统中的多小区干扰协调技术，多小区干扰协调技术对频谱资源和发射功率进行限制 <22>CQI 信道质量指示 <23>ZC- ZCZ零相关区域 <24>3G的网络由基站（NB）、无线网络控制器（RNC、服务通用分组无线业务支持节点 （SGSN ） 和网关通用分组无线业务支持节点（GGSN）4 个网络节点组成 <25>。eNB 的主要功能为: 在附着状态选择AGW；寻呼信息和广播信息的发送；无线资源的动态分配，包括多小区无线资源管理；设置和提供eNB 的测量；无线承载的控制；无线接纳控制；在激活状态的连接移动性控制。
移动通信的一些技术名词英文缩写解释
移动通信技术名词 英文解释 DRIFTED BY 417903263(fyt11111@https://www.sodocs.net/doc/1b15515065.html,)
动态范围: Dynamic range 频率偏值: Frequency offset 符号率：Symbol rate 码域功率：code domain power 频分多址: Frequency Division Multiple Access 码分多址: Code Division Multiple Access 时分多址: Time Division Multiple Access 沃什码：Walsh code 误码率：Bit Error Rate，BER 帧误码率：Frame Error Rate，FER 循环冗余码：Cyclic Redundancy Code，CRC 时序分析：timing analyze 门限：threshold 非同步模式：Asynchronous Mode 同步模式：Synchronous Mode 邻道功率：ACP D――Adjacent Channel Power 先进移动电话业务：AMPS---Advanced Mobile Phone Service 组织协会： ANSI --- American National Standard Institute 美国国家标准局 BPT --- British Post and Telecommunication Standard 英国邮政与电信标准 CCIR --- International Radio Consultative Committee 国际无线电咨询委员会 CCITT --- International Telegraph and Telephone Consultative Committee 国际/电报咨询委员会
通用英文缩写
中英对照 AAR 外观件批准报告 ADV 分析/开发/验证 ADV P&R ADV计划和报告 ADV-DV ADV设计验证 ADV-PV ADV产品验证 AIAG 汽车工业行为集团 AP 先期采购 APO 亚太分部 APQP 产品质量先期策划 ASQE 先期供应商质量工程师 BOM 材料清单 BOP 过程清单 Brownfield Site 扩建场地 CMM 三坐标测试仪 CPK 过程能力指数 CTS 零件技术规范 Defect outflow detection 缺陷检测 DFM/DFA 可制造性/可装配性设计 DPV 每辆车缺陷数 DRE 设计发放工程师 EQPE 工程质量规划工程师 Error Occurrence Prevention 设计发放工程师EWO 工程更改指令 FE1，2，3 1，2，3功能评估 FMEA 失效模式和后果分析 GD&T 几何公差&尺寸 GM 通用汽车公司 GME 通用汽车工期欧洲分部 GP 总体步骤 GP-4 生产件批准程序 GP-5 供应商质量过程和测量(问题回复及解决) GP-8 持续改进 GP-9 按节拍生产 GP-10 试验室认可程序 GP-11 样件批准 GP-12 早期生产遏制 GPDS 全球产品描述系统 GPS 全球采购系统 GQTS 全球质量跟踪系统 GR&R 量具的重复性与再现性 Greenfield Site 新建工厂
GVDP 全球车辆开发过程 IPTV 每千辆车缺陷数 KCC 关键控制特性 KCDS 关键特性指示系统 Kick-off Meeting 启动会议 KPC 关键产品特性 LAO 拉丁美洲分部 Layered Process Audit 分层审核 LCR 最低生产能力 Mcomplex system/subassembly M复杂系统/分总成MCR 最大生产能力 MOP 制造/采购 MPC 物料生产控制 MPCE 欧洲物料生产控制 MRD 物料需求日期(交样完成日期) MSA 测量系统分析 MVBns(原:NS) 非销售车制造验证 MVBs(原:S) 销售车制造验证 N.O.D. 决议通知 NAO 北美分部 NBH 停止新业务 OEM 主机客户 PAD 生产装配文件 PC&L 生产控制&物流 PDT 产品开发小组 FMEA 潜在失效模式分析 PPAP 生产件批准程序 PPK 过程能力指数 PPM （1）项目采购经理（2）每百万件的产品缺陷数PPO 样车试制工程 PQC 产品质量特性 PR/R 问题报告及解决 PSA 潜在供应商评审 PTR 零件试生产 QSA 质量系统评审 QTC 工装报价能力 RASIC 负责，批准，支持，通知，讨论 RFQ 报价要求 RPN 风险顺序数 RPN reduction plan 降低RPN值计划 S.T.E.P 采购定点小组评估过程 SDE 供应商开发工程师 SFMEA 系统失效模式分析 SMT 系统管理小组
常见英文缩写解释
常见英文缩写解释（按字母顺序排列）： ASIC: Application Specific Integrated Circuit. 专用IC CPLD: Complex Programmable Logic Device. 复杂可编程逻辑器件 EDA: Electronic Design Automation. 电子设计自动化 FPGA: Field Programmable Gate Array. 现场可编程门阵列 GAL: Generic Array Logic. 通用阵列逻辑 HDL: Hardware Description Language. 硬件描述语言 IP: Intelligent Property. 智能模块 PAL: Programmable Array Logic. 可编程阵列逻辑 RTL: Register Transfer Level. 寄存器传输级描述） SOC: System On a Chip. 片上系统 SLIC: System Level IC. 系统级IC VHDL: Very high speed integrated circuit Hardware Description Language. 超高速集成电路硬件描述语言 A ASIC（专用集成电路） Application-Specific Integrated Circuit. A piece of custom-designed hardware in a chip.专用集成电路。一个在一个芯片上定制设计的硬件。 address bus （地址总线） A set of electrical lines connected to the processor and all of the peripher als withwhich itcommunicates. The address bus is used by the processor to select aspecific memory location or register within a particular peripheral. If the address bus contains n electrical lines, the processor can uniquely address up to 2^n such locations.一个连接处理器与所有外设的，用来通讯的电子线路集。地址总线被处理器用来选择在特定外设中的存储器地址或寄存器。如果地址总线有n条电子线路，处理器能唯一寻址高达2^n的地址空间。 application software（应用软件） Describes software modules specific to a particular embedded project. The application softwar e is unlikely to be reusable across embedded platforms, simply because each embedded system has a different application.
通用英文缩略语
附录A：首字母缩写和缩略语 ACM 创利总额 AIAG 汽车工业行动小组 ALBS 装配线平衡系统 AP 提前采购 APPM 项目规划经理助理 APQP 产品质量先期策划 AR 拨款申请书 ASM 装配车间 ASQ&R 供应商先期质量和准备 ATS 空气/热能/密封一体化中心 AVCE 车辆副总工程师 AVLE 车辆生产线副执行主管 AVG 装配审核小组 BEC 基本工程内容 BIC 同类最佳产品 BIW 白车身 BIWDA 白车身数据分析仪 BLT 车身泄漏试验 BOM 材料清单 BOP 流程清单 BR 测试版本 B/S 车身车间 C4 计算机辅助设计、计算机辅助制造、计算机辅助工程、计算机集成制造 CAB 变更审批委员会 CAD 计算机辅助制图 CARE 用户接受度审查和评估 CAR 改正行动报告 CAS 概念可改变的选择 CCRW 控制机构、传送机、机器人和焊接 CDIS 通用尺寸信息处理系统 CEC 客户强化校准
CI 概念传授 CKD 全散件 CKDI 全散件方案启动 CMA 中心材料区 CMC 变更管理协调员 CML 变更管理主管 CMM 坐标测量机 CPIP 连续产品改进流程 CPIT 当前生产改进组 CR 变更申请书 CRB 变更审核委员会 CS 合同签订 CSO 合同签字同意 CSPC 常见稳定的零部件代码CTF 捕获试验车队 CTIS 公共教育训练信息处理系统CVER 概念车辆工程投放 CVIS 装配完整的车辆检查标准CVMS 公司车辆管理系统 CVS 装配完整的车辆标准 CY 日历年度 DCIP 尺寸控制检查计划 DE 设计工程师 DFA 装配设计 DFFA 尺寸适配、功能和外观DFM 可制造性设计 DM 交付物管理 DMA 数据管理行政官员 DMA 交付物/强制性管理分析师DMF 数据管理设备 DMS 文件管理系统 DMSS 尺寸管理稳定状态 DOA 加速持续时间 DPM 尺寸项目经理
管道英文缩写通用术语教学内容
管道英文缩写通用术 语
管道英文缩写通用术语 A Anchor 固定 ABS *Absolute 绝对的 AISI *American Iron and Steel Institute 美国钢铁学会 ANSI *American National Standards Institute 美国国家标准学会API *American Petroleum Institute 美国石油学会 APPROX *Approximate 大约，近似的 ASB Asbestos 石棉 ASME *American Society Of Testing Material 美国机械工程师协会 ASSY *Assembly 装配，组装ASTM *American Society Of Testing Material 美国材料实验协会ATM *Atmosphere 大气压 AWG *American Wire Gage 美国线规 AWS *American Wel**** Society 美国焊接协会 AWWA *American Water Works Association 美国水工协会 B BB Bolted Bonnet 栓柱连接的阀盖BB By Buyer 买方供货 B-B Beveled End-Beveled End 两端为坡口端 BC Bolt Circle 螺栓中心圆 B.C Bolted Cover(cap) 螺栓连接的阀兰盖（帽） BE Beveled End (for wel****) 坡口（焊接用） B.E Bell End 承口 BEP Both Ends Plain 两端平 BET Both Ends Threaded 两端带螺纹 BL Battery Limit 装置区边界 BF Blind Flange 法兰盖 BLD Blind 盲板 BLDG *Buil**** 建筑物 BM Bill Of Material 材料表 BOP Bottom Of Pipe 管底