A comparative study on MEMS piezoelectric microgenerators
REVIEW PAPER
A comparative study on MEMS piezoelectric microgenerators
Aliza Aini Md Ralib ?Anis Nurashikin Nordin ?
Hanim Salleh
Received:23November 2009/Accepted:14April 2010/Published online:21May 2010óSpringer-Verlag 2010
Abstract The growing demand of wireless sensor net-works has created the necessity of miniature,portable,long lasting and easily recharged sources of power.Traditional,hazardous batteries are rendered unacceptable and the viability of ‘green’MEMS energy harvesters has become even more dominant.This paper reviews the state-of-the-art MEMS piezoelectric energy harvesters which promise a cleaner environment and eliminate the disposal issue of conventional batteries.Piezoelectric devices are the perfect candidate for implementation in micro generators as they are easily fabricated,are silicon compatible and demon-strate high ef?ciencies for mechanical to electrical energy conversion.The characteristic equations which govern the conversion of mechanical vibration to electrical power are described in this paper.The typical operating modes for MEMS piezoelectric energy cantilevers which are namely;d 31and d 33are also detailed.Criteria for optimum material suitable for MEMS energy scavengers to produce maxi-mum power output are also outlined.Several MEMS energy harvesters which have been successfully fabricated and tested are also critically reviewed in this paper.Finally a comparison table highlighting the advantages and dis-advantages of each work is presented.
1Introduction
Signi?cant miniaturization of electro-mechanical devices using complementary metal-oxide semiconductor (CMOS)and micro-electro-mechanical systems (MEMS)technolo-gies have encouraged the creation of miniature energy harvesters (Schmitz et al.2005)The demand for increased portability for wireless sensor nodes has created the necessity of replacing bulky conventional batteries with miniature micro-generators.The battery replacement task is one of the sources of failure for wireless sensor networks with many embedded nodes (Beeby et al.2006).When deployed in remote areas,low power characteristics of wireless sensor network components are crucial to ensure longer lifetime of the wireless sensor.
Energy harvesters offer a more promising solution in terms of cost,portability,ease of use and environmental-friendliness.Energy harvesters are considered as a renew-able energy device due to its capability of converting electrical energy from unused ambient energy in the sen-sor’s environment.The main idea behind MEMS micro generator is to capture the available ambient energy and to transform it into electrical energy as shown:
Energy Conversion
eTranslateambient energy into electrical energy T
!Energy harvesting module for Microgenerator
Power capturing ;storage and management eT
!End Application
Enable wireless sensor network application eT
Some sources of ambient energy are heat and mechanical vibrations.Energy from mechanical vibrations can be harvested by the use of (1)piezoelectric (piezoelectric material converts from strain into electrical energy),(2)electromagnetic (in which a magnet is attached to the mass to induce a current in a coil as it moves)or (3)electrostatic
A.A.M.Ralib (&)áA.N.Nordin
Department of Electrical and Computer Engineering,
Kulliyyah of Engineering,International Islamic University Malaysia,Kuala Lumpur,Malaysia e-mail:aliza.aini@https://www.sodocs.net/doc/c96705390.html,.my A.N.Nordin
e-mail:anisnn@https://www.sodocs.net/doc/c96705390.html,.my
H.Salleh
Department of Mechanical Engineering,College of Engineering,Universiti Tenaga Nasional Malaysia,Selangor,Malaysia e-mail:HANIM@https://www.sodocs.net/doc/c96705390.html,.my
123
Microsyst Technol (2010)16:1673–1681DOI 10.1007/s00542-010-1086-9
(in which a charge on the mass induces a voltage on a capacitor as it moves).Some of the applications of energy harvesting are long term medical monitoring and embedded sensors in buildings.The trend is now to develop micro power generators(Paradiso and Starner2005)that can harvest energy for condition monitoring applications.This device can be positioned on a gas turbine in power plants where at a critical vibration pattern it will generate power to
activate a wireless sensor to caution for maintenance. Wireless systems offer a huge advantage in condition monitoring applications because of the?exibility and ease of implementation at typically inaccessible locations.
This paper emphasizes energy harvesters which utilize the piezoelectric conversion mechanism.Piezoelectric devices are the perfect candidate for implementation in micro generators as they can ef?ciently convert mechanical strain to electrical charge without any additional power. There has been a signi?cant interest in vibration based energy harvesting for low power applications such as pagers,self powered emergency receivers,radio frequency identi?cation(RFID)tags or locators(Shenck and Paradiso 2001).
Choi et al.(2006)reported that one such MEMS device is a thin?lm piezoelectric power generator which employs the d33mode with measured performance of1l W. Another prototype of piezoelectric cantilever is capable of generating270nW when operating at the resonance fre-quency of229Hz(Kok et al.2008).To improve power output and to provide frequency?exibility,Liu et al. (2008)proposed an array of MEMS piezoelectric power generators.This device array has a measured performance of3.98l W effective electrical power and3.93DC output voltages with bandwidth of226–234Hz.
This paper explains the principle of piezoelectric energy harvesting and provides a comparative study on existing MEMS piezoelectric micro generators.The rest of the paper is organized as follows.Section2explains on the piezoelectric principle and design.Section3presents the state of the art MEMS devices and its emerging applica-tions.A comparative study of this recent work is tabulated and discussed in Sect.4.Finally,the conclusion is given in Sect.5.
2Piezoelectric principle and design
2.1Conversion design
The cantilever structure with proof mass at the end has proven to be the most popular structure for the energy conversion design from mechanical vibration to electrical power.Researchers have extensively applied this con?gu-ration for piezoelectric energy harvesting device(Kok et al.2008;Liu et al.2008;Choi et al.2006;Hyunuk et al.2008, 2009;Lee et al.2007).The direction of vibration is shown with an arrow in Fig.1.
The piezoelectric energy conversion can be described using the equivalent linear spring mass system as shown in Fig.2.
M€ztC_ztKz?àM€ye1Twhere z=x-y is the net displacement of mass,M is the lumped mass,K is the spring constant and C is the damping coef?cient(Hyunuk et al.2009).
The natural frequency of spring mass system,x n can be written as
x n?
????
k
m
r
e2TUsing the model of the power output of the system at resonance is
P max?
mY2x3
n
4f
e3TWhere m is the seismic mass,Y is the amplitude vibration x is the system resonance frequency and f is the relative damping ratio.The output power is directly proportional to mass which means that the converter size directly affects the power output produced as shown in(3).Power is inversely proportional to the damping ratio,which is dependent on the selection of materials and the design of the device.Output power of the system is optimized if
the Fig.1Cantilever beam with tip
mass
Fig.2Schematic of generic vibration converter
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piezoelectric system is operating at its resonance frequency (Hyunuk et al.2009).
In terms of excitation acceleration levels of the input vibration(a),the power output can be displayed in(4) where a=x n2Y(Beeby et al.2006).
P max?ma2
4x n f
e4T
As shown in(4),the output power decreases as frequency increases because the input vibrations amplitude decreases with frequency.The output power also proportional to the square of acceleration(Hyunuk et al.2008).Furthermore, Liu et al.(2008)reported that most sources of ambient vibration are in low frequency(\1,000Hz).As such,to optimize output power,an energy harvesting device should operate at lower frequencies(Liu et al.2008).
2.2Operating mode of piezoelectric transducer
With reference to the Fig.3,two frequent modes that are applied for energy harvesting devices are the d33and d31 modes.In the d31mode,stress is applied in the axial direction but voltage is obtained in the perpendicular direction.In contrast,for the d33mode,the applied stress has the same direction as the generated voltage.Choi et al. (2006)reported that the d31mode has separate top and bottom electrodes while the d33mode employs only top interdigital electrodes.The d33mode design gives a much higher open circuit voltage which is needed to overcome the forward bias of the rectifying diodes(Choi et al.2006).
2.3Piezoelectric material selection
Suitable piezoelectric material is characterized by the product of piezoelectric energy constant(g)and piezo-electric strain coef?cient(d)given as|d.g|(Hyunuk et al. 2009).The types of material can be categorized into four namely:piezoelectric polycrystalline ceramics,piezoelec-tric single crystal materials,piezoelectric and electrostric-tive polymers and piezoelectric thin?lms.
PZT(lead zicronate titanate)is a polycrystalline ceramic which shows good piezoelectric strain and coupling coef?cients as shown in Table1(Roundy et al.2003).PZT thin?lms can be constructed from materials such as Pb(Zr, Ti)O3(PZT),AlN and BaTiO3.They are commonly used for sensor applications.PZT polycrystalline thick?lms are widely used to fabricate MEMS scale energy harvesting devices(Hyunuk et al.2008).PZN-PT(lead zinc niobate–lead titanate)is a single crystal material which has excel-lent properties compared to PZT.However,PZN-PT is not typically used for microgenerators since they are dif?cult to fabricate in MEMS,are very expensive and only very small crystals can be produced(Roundy et al.2003).PVDF (polyvinylidene?uoride)is a semi crystalline polymer which is approximately half crystalline and half amor-phous.PZT is reported to be the optimum piezoelectric material for micro generators based on the comparison done;due to the ease of fabrication and high power output produced(Roundy et al.2003).
3Recent techniques in MEMS micro generators There has been signi?cant interest in the vibration based energy harvesting for low power applications research (Shenck and Paradiso2001).In this section,nine recent previous works will be discussed comprehensively.
A complete comparison table is also attached at the end of the discussion.
3.1Work1:MEMS based piezoelectric power
generator array for vibration energy harvesting
Fang et al.(2006)demonstrated a generator formed of composite cantilever with nickel as its metal mass.The prototype generator was fabricated using MEMS process-ing techniques such as sol-gel,dry reactive-ion-etching (RIE)and wet chemical etching.The measured output performance was0.89AC peak–peak voltage output and 2.16l W power output at608Hz resonant frequency.
Though the micro-generator is functioning satisfactorily, Liu et al.(2008)concluded that with speci?c dimensions, such cantilevers have?xed and narrow frequencies and are capable of producing only l W level power output.To improve power output and to offer frequency?exibility,an overlapping effect of resonance frequencies was introduced by designing a power generator array based on multiple cantilevers.The available bandwidth covers the range of minimum and maximum resonance frequencies of the cantilevers in an array.This generator array has a measured performance of3.98l W electrical power and3.93V DC output voltage to a resistive load and resonance frequencies ranging from226to234Hz(Liu et al.2008).As shown in Fig.4,the piezoelectric material used is thick?lm PZT with Pt/Ti as the top and bottom electrodes.Ni
material Fig.3Operating mode of piezoelectric transducer
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was chosen for the proof mass.This design shows that the array of devices is a promising method to improve power output and bandwidth of the micro generator.3.2Work 2:Energy harvesting MEMS device based on
thin ?lm piezoelectric cantilevers A thin ?lm piezoelectric MEMS cantilever energy harvester was developed by Choi et al.(2006).The dimensions of the
cantilever were 1709260l m.The chosen structure of the design is bimorph with a proof mass at the end as shown in Fig.5.A thin ?lm of lead zirconate titanate,Pb (Zr,Ti)O 3(PZT)was chosen as the piezoelectric material.The top Pt/Ti electrodes were patterned as interdigital electrodes on top of the PZT thin ?lm to operate in the d 33mode.The generator had a measured performance of 1l W electrical power and 2.4V DC output voltage when measured across a 5.2M X resistance load.The device has three resonance modes namely;13.9,21.9and 48.5kHz (Choi et al.2006;Jeon et al.2005).A highlight of the work is a discussion on the relationship between the proof mass and the power output produced.The work reports that for a speci?c reso-nant frequency,the output power is proportional to the weight of the proof mass.
P out e€x B T
?m eff 1x N rk 2e R eq .R l X 2
?1àe1t21m r TX 2 t?e1tk 2e Tr X t21m
X àr X 3 e5T
The generated power for a given input vibration
amplitude is derived (Choi et al.2006)as shown in (5)where P out is the output power,x B is the input vibration amplitude,m eff is the effective mass of the structure and x N is the natural frequency of the structure.The equivalent resistance (r )is equal to R l R p /(R l ?R p );where R l is the
Table 1Comparison of piezoelectric materials
Source:(Roundy et al.2003)and (Hyunuk et al.2009)
Material Type
Strain coef?cient (10-12m/v)PZT 701Polycrystalline ceramics d 31320d 33650PZT-4Piezoelectric thin ?lms
d 33289PVDF Piezoelectric and electrostrictiv
e polymers d 3120d 3330PZN-PT
Single crystal materials d 31950d 332,000BaTiO 3
Piezoelectric thin ?lms
d 33
191
Fig.4Schematic con?guration of single cantilever
beam Fig.5Side and top view of d33mode of piezoelectric devices
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load resistance,R p is the leak resistance of microgenerator,X is the relative frequency (x input /x N )and 1m is the mechanical damping coef?cient (Choi et al.2006).Equation (5)indicated that the heavier the mass,the stiffer the beam and therefore,more power can be stored into the structure.
3.3Work 3:A free standing thick ?lm piezoelectric
energy harvester A free standing thick ?lm cantilever was fabricated using conventional thick ?lm and sacri?cial layer fabrication techniques (Kok et al.2008).The dimensions of the can-tilever were 13.5mm long by 9mm wide with total thickness of 192l m.Again,thick ?lm lead zirconate titanate (PZT)was chosen.The device produced an output voltage up to 130mV when driving a 60k X resistor and resonating at 229Hz.Ag/Pd was chosen as the top and lower electrodes and the device operates in the d 31mode.Figure 6shows the fabrication steps of a free standing thick ?lm piezoelectric energy harvester.The resonant frequency of the cantilever decreases with added mass as shown in (6)where j the spring is constant is the effective proof mass V n 2is the eigenvalue of the n th mode of vibration and f n is the resonant frequency.
m eff ?j 12:71V 2n
2P f n 2e6T
Kok et al.(2008)also proved that additional proof mass improves the output electrical power.Typically,powers generated from the vibration devices are relatively small (*270nW).However,excessive proof mass leads to energy dissipation due to damping effects in the cantilever beam (Kok et al.2008).
3.4Work 4:Two layered piezoelectric bender device
for micro power generator A two layered piezoelectric bender device for micro gen-erator was designed as shown in Fig.7(Jeong et al.2008).The piezoelectric ceramic used was 0.2Pb (Mg 1/3Nb 2/3)O 3–0.8Pb (Zr 0.475Ti 0.525)O 3(PMNZT).Bender type pie-zoelectric devices show signi?cant change in power with small deviations of frequency.As such,when the thick-nesses of the two layered device were varied in four samples,each layer shows a different resonant frequency as shown in Fig.8.The samples were placed under different frequencies of vibration (88,100,110and 120Hz)and the output voltage of each sample was measured with respect to time.Each sample showed maximum output voltage when excited at its resonant vibration frequency (Jeong et al.2008).The generator has a measured performance of peak to peak voltage of 2.0V and power of 0.5mW of acceleration 0.1G (G =0.981m/s 2)at 120Hz in reso-nance mode (Jeong et al.2008
).
Fig.6Fabrication steps for free standing piezoelectric energy
harvester
Fig.7Two layer structure of piezoelectric bender devices (Jeong et al.2008)
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3.5Work 5:Piezoelectric scavengers in MEMS
technology:fabrication and simulation
Schmitz et al.(2005)designed and fabricated several pie-zoelectric devices differing in geometry and electrical connections on one wafer.Figure 9shows the piezoelectric generator located on top of a beam.The micro-generator consists of a piezoelectric layer sandwiched between top (Al)and bottom (Pt)electrodes.Three different mass dimensions (393mm 2,595mm 2,797mm 2)were designed.The change in length and width of the beam results in variation of the devices’resonance frequencies (300,700,and 1,000Hz).The devices are designed as single piezoelectric generators or as a series connection of four piezoelectric generators.Schmitz et al.(2005)pro-vided a comparison of fabrication using two different pie-zoelectric materials namely PZT and AlN.PZT has a higher piezoelectric constant compared to AlN.However,fabri-cation wise,the deposition of PZT layer is more time consuming and involves multiple steps compared to AlN (Schmitz et al.2005).AlN provides more favorable material parameters and has better composition control e.g.up to three times faster deposition and better composition due to AlN stoichiometric structure (Small Times 2009).The simplicity of AlN fabrication,which is merely sputtered on,makes it low-cost and easily compatible to standard CMOS and MEMS processes.Finally,the piezoelectric device is wafer bonded and encapsulated between two wafers.Such
protection indicates that the microgenerator operates in vacuum and thus reducing air-damping of the beam.The ?nished piezoelectric energy harvester weighs only 34mg and is capable of generating 60l W electrical power at 500Hz resonance frequency.
3.6Work 6:Piezoelectric harvesters and MEMS
technology This work illustrates a piezoelectric energy harvester with measured maximum output power of 40l W for input vibrations of 1.8kHz frequency and 80nm amplitude (Renaud et al.2007).As illustrated in Fig.10,the device is a piezoelectric capacitor formed using PZT layer with an Al electrode on the top and Pt electrode at the bottom.A small proof mass was attached to the tip of the cantilever.It was wafer-bonded between two capping wafers with electrical contacts openings and appropriate cavities allowing the motion of mass.Renaud et al.also presented a theoretical electromechanical model which estimates the output power of the encapsulated piezoelectric energy scavenger when connected to a resistive load.Some assumptions have been made during the development of the model such as;the frequency of the input vibration is close to one of the natural frequencies of the bender,the mass of the bending system is negligible with respect to the one attached at its end and the different modes of resonance of the structure do not interfere with each other.The model provided a method of approximating the output
power.
Fig.8Geometry of bender devices (t1=250l m,
t1=220l m,t1=180l m,t1=160l
m)
Fig.9Piezoelectric scavengers in MEMS technology (Schmitz et al.2005
)
Fig.10Schematic drawing of piezoelectric scavenger (Renaud et al.2007)
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Minor discrepancies exist between the model and experi-mental results due to neglected nonlinear effects and losses (Renaud et al.2007).
3.7Work 7:Laser machined piezoelectric cantilevers
for mechanical energy harvesting A piezoelectric material based mechanical energy harvester fabricated using a combination of laser machining tech-nique and microelectronics packaging technology was reported (Hyunuk et al.2008).The device was tested at low frequency range of 50–1,000Hz at constant force of 8G (G =9.81m/s 2).Pb (Zr 0.52Ti 0.48)O 3–Pb(Zn 1/3Nb 2/3)O 3was chosen as the piezoelectric material.It was reported that laser machining process did not give signi?cant effect on the electrical properties of piezoelectric material (Hyunuk et al.2008).Figure 11shows ten cantilevers on both sides of the bridge which were electrically connected in parallel.The tip masses were deposited on alternate cantilevers to ensure that each cantilever vibrates at a different resonance frequency,thus providing a wider fre-quency range (Hyunuk et al.2008).The whole package was mounted on the top of a shaker.The variation of the output voltage versus frequency were measured.Interest-ingly enough,the measured resonance peaks were at 870and 270Hz,which were far from the simulated value of 47.1and 14.8kHz.This deviation in frequency was attributed to the rocking and bouncing mode of the chip package which was mounted on an aluminum bar.Under such experimental conditions,the device has a measured performance of 1.13l W electrical power when resonating at 870Hz across 288.5k X load and 0.06l W electrical power when resonating at 270Hz across 949k X .The calculated power density is 301.3l W/cm 3.It can be con-cluded that a high energy density device can be fabricated using the combination of laser machining and IC fabrica-tion techniques.Optimum energy density is achieved when using the appropriate cantilever dimensions,number of cantilevers on a wafer,weight of the tip mass and PZT material characteristics (Hyunuk et al.2008).
3.8Work 8:Power harvesting using piezoelectric
MEMS generator with interdigital electrodes Lee et al.(2007)designed a piezoelectric MEMS generator consisting of a silicon beam structure laminated with PZT (lead zirconate titanate).Interdigital electrodes were placed on top of the PZT layer to transform mechanical strain energy into electrical charge when operating using the d 33mode.The gaps of the interdigital electrodes were varied and the power performance was evaluated.A proof mass was attached at the tip of the beam as shown in Fig.12.The beam structure was designed to operate at its resonant frequency of 570Hz to maximize stress,strain and output power.Varying the distance between interdigital electrodes in turn varies the output power since the output voltage is a function of the output charge and the capacitance between interdigital electrodes.The dimensions of the cantilever generator were 3,000l m 91,500l m with 22l m beam thickness.The thickness of the SOI wafer and PZT layer were and 10and 12l m respectively.A 50nm Ti and 200nm Pt metal layer was then deposited on top of the wafer using the E-beam evaporator.Experimental mea-surements of the device were conducted by mounting the piezoelectric MEMS generator on a shaker and measuring its output voltage via a buffer circuit.Devices of varying interdigital electrodes gaps of 20,30and 40l m were measured.Experimental results indicate that the higher the gap distances between electrodes,the larger the output power (Lee et al.2007).The maximum power output of 0.0471l W was obtained from the MEMS generator with 40l m gap.
4Performance evaluation for piezoelectric energy harvesters Piezoelectric micro-generators based on the cantilever beam structure were chosen for discussion due to its sim-plicity and compatibility with MEMS technologies.MEMS energy harvesters have the challenge of having
low
Fig.11Assembled PZT wafer with tip mass (Hyunuk et al.2008
)
Fig.12Schematic graph of the piezoelectric MEMS generator (Lee et al.2007)
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T a b l e 2C o m p a r i s o n t a b l e f o r p i e z o e l e c t r i c e n e r g y h a r v e s t i n g
P r e v i o u s w o r k P i e z o e l e c t r i c m a t e r i a l s
D e s i g n
R e s o n a n t f r e q u e n c y O u t p u t p o w e r o r v o l t a g e F a b r i c a t i o n
W o r k 1.M E M S b a s e d p i e z o e l e c t r i c p o w e r g e n e r a t o r a r r a y f o r v i b r a t i o n e n e r g y h a r v e s t i n g (L i u e t a l .2008)T h i n ?l m l e a d z i r c o n a t e t i t a n a t e P b (Z r ,T i )O 3(P Z T )C a n t i l e v e r s i z e :L e n g t h =2,000–3,500l m W i d t h =750–1,000l m 226–234H z d 31m o d e
O u t p u t v o l t a g e o f 3.93V D C O u t p u t p o w e r o f 3.98l W F u n c t i o n a l ?l m p r e p a r a t i o n a n d p a t t e r n ,b u l k s i l i c o n m i c r o m a c h i n i n g ,s t r u c t u r e r e l e a s e a n d m a s s a s s e m b l a g e W o r k 2.E n e r g y H a r v e s t i n g M E M S d e v i c e b a s e d o n t h i n ?l m p i e z o e l e c t r i c c a n t i l e v e r s (C h o i e t a l .2006)
T h i n ?l m l e a d z i r c o n a t e t i t a n a t e P b (Z r ,T i )O 3(P Z T )C a n t i l e v e r s i z e :L e n g t h =170l m W i d t h =260l m 3m o d e :13.9,21.948.5k H z O u t p u t v o l t a g e o f 2.4V a t 5.2M X l o a d O u t p u t p o w e r o f 1.01l W T h r e e p h o t o m a s k s t e p s D e p o s i t i o n v i a s o l g e l m e t h o d ,p a t t e r n e d v i a R I E
W o r k 3.A f r e e s t a n d i n g t h i c k ?l m p i e z o e l e c t r i c e n e r g y h a r v e s t e r (K o k e t a l .2008)
T h i c k ?l m l e a d z i c r o n a t e t i t a n a t e (P Z T )
C a n t i l e v e r s i z e :L e n g t h =13.5m m W i d t h =9m m T h i c k n e s s =192l m
229H z d 31m o d e O u t p u t v o l t a g e o f 130m V O u t p u t P o w e r o f 270n W a t 9.81m /s 2
S a c r i ?c i a l l a y e r W o r k 4.T w o l a y e r e d p i e z o e l e c t r i c b e n d e r d e v i c e s f o r m i c r o p o w e r g e n e r a t o r (J e o n g e t a l .2008)
0.2P b (M g 1/3N b 2/3)O 3–0.8P b (Z r 0.475T i 0.525)O 3(P M N Z T )
C a n t i l e v e r s i z e :L e n g t h =10m m W i d t h =10m m
120H z
P e a k -t o -p e a k v o l t a g e o f 2.0V a n d a p o w e r o f 0.5m W i n r e s o n a n c e m o d e T h e s t r u c t u r e c o n s i s t o f f o u r l a y e r s w a s d e s i g n e d w i t h v a r i o u s t h i c k n e s s
W o r k 5.P i e z o e l e c t r i c s c a v e n g e r s i n M E M S t e c h n o l o g y :f a b r i c a t i o n a n d s i m u l a t i o n (S c h m i t z e t a l .2005)
1.A l N
2.P Z T L e a d z i c r o n a t e t i t a n a t e P b Z r 0.53T i 0.47O 3
T h e p i e z o e l e c t r i c g e n e r a t o r i s l o c a t e d o n t o p o f t h e b e a m a n d c o n s i s t s p i e z o e l e c t r i c l a y e r s a n d w i c h e d b e t w e e n t o p a n d b o t t o m e l e c t r o d e
300–1,000H z V a r i a t i o n o f r e s o n a n c e f r e q u e n c i e s :300,700,1,000H z 1–100l W A l N l a y e r i s d e p o s i t e d a n d p a t t e r n e d b y u s i n g a c o m b i n a t i o n o f s p u t t e r i n g a n d l i t h o g r a p h y
W o r k 6.P i e z o e l e c t r i c h a r v e s t e r s a n d M E M S t e c h n o l o g y (R e n a u d e t a l .2007)
P Z T
T h e d e v i c e i s p a c k a g e s u s i n g t w o w a f e r s 1.8k H z 40l W
A p i e z o e l e c t r i c c a p a c i t o r
f o r m e d b y a b o t t o m o f P t e l e c t r o d e ,a P Z T l a y e r a n d a t o p o f A l e l e c t r o d e i s f a b r i c a t e d o n a c a n t i l e v e r w h i c h s u p p o r t m a s s a t t a c h e d t o i t s t i p
W o r k 7.L a s e r m a c h i n e d p i e z o e l e c t r i c c a n t i l e v e r s f o r m e c h a n i c a l e n e r g y h a r v e s t i n g (H y u n u k e t a l .2008)
P b (Z r 0.52T i 0.48)O 3–P b (Z n 1/3
N b 2/3)O 310c a n t i l e v e r s o n b o t h s i d e o f t h e b r i d g e ,5o f t h e m a r e p l a c e d w i t h t i p m a s s a l t e r n a t e l y .W i d t h =4m m L e n g t h =5.75m m
870H z O u t p u t p o w e r o f 1.13l W a t 870H z t h r o u g h 288.5k X l o a d .P o w e r d e n s i t y o f 301.3l W /c m 3L a s e r m a c h i n i n g
W o r k 8.P o w e r H a r v e s t i n g U s i n g P i e z o e l e c t r i c M E M S G e n e r a t o r w i t h I n t e r d i g i t a l E l e c t r o d e s (L e e e t a l .2007)L e a d Z i c r o n a t e T i t a n a t e (P Z T )C a n t i l e v e r s i z e :L e n g t h =3,000l m W i d t h =1,500l m T h i c k n e s s =22l m
570–575H z O u t p u t v o l t a g e o f 1.127V P -P ,O u t p u t p o w e r o f 0.123l W D e p o s i t i o n ,b e a m s h a p e p a t t e r n a n d R I E a n d D R I E e t c h i n g
1680
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resonant frequencies to capture low-frequency,ambient mechanical vibrations while keeping the miniature sizes of MEMS devices(Choi et al.2006).Table2indicates that PZT(lead zicronate titanate)is the choice piezoelectric material due to its high piezoelectric strain and coupling coef?cients.Deposition of PZT layer however,is time consuming and involves multiple steps compared to AlN (Schmitz et al.2005).In terms of fabrication,AlN layer is more suitable due to its ease of processing and compati-bility with MEMS and CMOS technology.A crucial key in PZT micro energy scavenger design for optimized output is operation in the d33mode.The d33mode design gives a much higher open circuit voltage which is needed to overcome the forward bias of the rectifying diodes(Choi et al.2006).When operating at the same resonant fre-quency,devices with heavier proof mass can scavenge more energy as reported by Kok et al.(2008).Overlapping resonance frequencies can be implemented by designing a power generator array based on multiple cantilevers to improve power output and frequency?exibility(Liu et al. 2008).The increase in gaps between the interdigital elec-trodes is also one of the crucial factors to increase the performance of the piezoelectric micro generators(Lee et al.2007).Finally,encapsulation of the cantilever within two capping wafers,forcing cantilever to vibrate in vacuum also translates to enhanced output power(Schmitz et al. 2005;Renaud et al.2007).
5Conclusion
In conclusion,the piezoelectric vibration energy harvester represents a very attractive solution to power ubiquitously deployed wireless sensor networks.Such piezoelectric micro-energy scavengers are versatile and suitable for many applications due to their higher output power densities, robustness and lesser complexity when compared to devices with other energy harvesting mechanisms.Selections of appropriate piezoelectric materials are signi?cant and crit-ical to ensure the highest output power produced.Other signi?cant factors such as weight of proof mass,gaps of interdigitated electrodes and the overlapping effect of res-onance frequencies also helps to maximize output power. Acknowledgments This research was supported by a grant from Tenaga Nasional Berhad Malaysia under the collaborative effort between Universiti Tenaga Nasional and International Islamic Uni-versity Malaysia.References
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意法半导体发布迄今性能最强的电视系统芯片
意法半导体发布迄今性能最强的电视系统芯片 横跨多重电子应用领域、全球领先的半导体供应商、全球领先的数字 电视及机顶盒芯片提供商意法半导体(STMicroelectronics，简称ST)将在2012 中国国际广播电视信息网络展览会(CCBN)上展出Newman 电视系统芯片(System-on-Chip，SoC)系列的首款产品。新系列产品是意法半导体的业界领先的电视广播互联网服务多功能电视平台的一部分。代号为Newman Ultra 的新产品FLI7680 拥有市场上无与伦比的性能，亦代表了智能电视(Smart TV)系统芯片技术水平的一次巨大飞跃。 随着高价值内容不断演进，除第一代电视广播宽带上网综合服务外，电 视还需要支持全新的增值服务和产业生态系统，例如Google TV。Newman Ultra 系统架构具有市场领先的性能，让电视应用程序具有令人惊喜的反应速度，同时拥有极其出色的视频解码功能，远超市场同类产品。有了这款芯片，消费 者只需通过一台智能电视机即可播放多种视频源，运行大量应用软件。 意法半导体WAVE 产品部总经理Luigi Mantellassi 表示：随着智能电视的概念正在快速演进，对处理性能、功能集成度、设计灵活性和数据安全的要 求不断提高。凭借我们在全球市场的领先地位和机顶盒软件开发能力，Newman Ultra 系统芯片让我们的客户能够扩大品牌价值，研制一个集传统电视广播、视频点播(Video on Demand，VOD)、游戏以及社交网络于一体的终极娱乐平台。 在优化平板电视技术的同时，Newman Ultra 还将继续使用Faroudja 品牌的音视频处理创新技术，为消费者带来无与伦比的视听盛宴。从大屏幕投影影院，到4Kx2K 3D 大屏幕，Faroudja 仍然是市场公认的高品质标杆。
《葛底斯堡演讲》三个中文译本的对比分析
《葛底斯堡演讲》三个中文译本的对比分析 葛底斯堡演讲是林肯于19世纪发表的一次演讲,该演讲总长度约3分钟。然而该演讲结构严谨,富有浓郁的感染力和号召力,即便历经两个世纪仍为人们津津乐道,成为美国历史上最有传奇色彩和最富有影响力的演讲之一。本文通过对《葛底斯堡演讲》的三个译本进行比较分析,从而更进一步加深对该演讲的理解。 标签：葛底斯堡演讲,翻译对比分析 葛底斯堡演讲是美国历史上最为人们所熟知的演讲之一。1863年11月19日下午,林肯在葛底斯堡国家烈士公墓的落成仪式上发表献词。该公墓是用以掩埋并缅怀4个半月前在葛底斯堡战役中牺牲的烈士。 林肯是当天的第二位演讲者,经过废寝忘食地精心准备,该演讲语言庄严凝练,内容激昂奋进。在不足三分钟的演讲里,林肯通过引用了美国独立宣言中所倡导的人权平等,赋予了美国内战全新的内涵,内战并不仅是为了盟军而战,更是为了“自由的新生(anewbirthoffreedom)”而战,并号召人们不要让鲜血白流,要继续逝者未竞的事业。林肯的《葛底斯堡演讲》成功地征服了人们,历经多年仍被推崇为举世闻名的演说典范。 一、葛底斯堡演说的创作背景 1.葛底斯堡演说的创作背景 1863年7月1日葛底斯堡战役打响了。战火持续了三天,战况无比惨烈,16万多名士兵在该战役中失去了生命。这场战役后来成为了美国南北战争的一个转折点。而对于这个位于宾夕法尼亚州,人口仅2400人的葛底斯堡小镇,这场战争也带来了巨大的影响——战争遗留下来的士兵尸体多达7500具,战马的尸体几千具,在7月闷热潮湿的空气里,腐化在迅速的蔓延。 能让逝者尽快入土为安,成为该小镇几千户居民的当务之急。小镇本打算购买一片土地用以兴建公墓掩埋战死的士兵,然后再向家属索要丧葬费。然而当地一位富有的律师威尔斯(DavidWills)提出了反对意见,并立即写信给宾夕法尼亚州的州长,提议由他本人出资资助该公墓的兴建,该请求获得了批准。 威尔斯本打算在10月23日邀请当时哈佛大学的校长爱德华(EdwardEverett)来发表献词。爱德华是当时一名享有盛誉的著名演讲者。爱德华回信告知威尔斯,说他无法在那么短的时间之内准备好演讲,并要求延期。因此,威尔斯便将公墓落成仪式延期至该年的11月19日。 相比较威尔斯对爱德华的盛情邀请,林肯接到的邀请显然就怠慢很多了。首先,林肯是在公墓落成仪式前17天才收到邀请。根据十九世纪的标准,仅提前17天才邀请总统参加某一项活动是极其仓促的。而威尔斯的邀请信也充满了怠慢,
意法ST系列芯片型号
ST(意法半导体)提供全系列具备各种外设的稳定型8位单片机以及高性能32位ARM芯片。ST系列单片机的8位ST6系列一直以来都是面向简单强劲的成本敏感型应用的安全并受到广泛欢迎的选择，其中包括家庭应用、数字消费类设备和电机控制。ST6器件采用16引脚到28引脚封装，内部集成了1到4KB的OTP(一次性可编程)或ROM存储器。 ST62E系列单片机： ST62E01, ST62E01C, ST62E01CF1, ST62E10, ST62E18, ST62E18C, ST62E18CF1, ST62E20, ST62E20B, ST62E20C, ST62E20CF1, ST62E25, ST62E25C, ST62E25CF1, ST62E28CF1, ST62E28C6, ST62E30B, ST62E30BF1, ST62E32BF1, ST62E40BG1, ST62E42BG1, ST62E46BG1, ST62E60B, ST62E60C, ST62E62CF1, ST62E62B, ST62E62C, ST62E65B, ST62E65C, ST62E65CF1, ST62E80B, ST62E80BG1, ST62E85BG1； ST62T系列单片机： ST62T00, ST62T01, ST62T03, ST62T08, ST62T09, ST62T10, ST62T15, ST62T18, ST62T20, ST62T25, ST62T28, ST62T30, ST62T32, ST62T40, ST62T42, ST62T46, ST62T52, ST62T53, ST62T55, ST62T60, ST62T62, ST62T63, ST62T65, ST62T80, ST62T85； ST62系列单片机：ST6200C, ST6201C, ST6203C, ST6210C, ST6220C, ST6225C, ST6260C, ST6262C, ST6265C； ST63E系列：ST63E73 …… ST7系列单片机解密： ST7FOXF1, ST7FOXK1, ST7FOXK2, ST7FOXA0； ST7LITE0, ST7LITE2, ST7LITE49K2, ST7LITE39F2, ST7LITE30F2, ST7LITE35F2, ST7LITE49M, ST7LITE1xB, ST7LITEU09, ST7LITEU05, ST7LITEUS5, ST7LITEUS2； ST72260G, ST72262G, ST72264G, ST72321, ST7232A, ST72321B, ST72321M, ST72325, ST72323, ST72323L, ST72340, ST72344, ST72345, ST72324B, ST72324BL, ST72361, ST72521B, ST72561, ST7260, ST7263B, ST7265, ST7267R8, ST7267C8, ST72681, ST72682； ST72C216 ST7LCRE4U1, ST7LCRDIE6, ST7SCR1R4, ST7SCR1E4； ST7GEME4, ST7LNB0V2Y0, ST72F521, ST72F324L； ST7LNB1Y0, ST7MC1, ST7MC2, ST7DALIF2, ST7SUPERLITE； ST10系列单片机解密： 新ST10闪存系列：ST10F271Z1, ST10F272Z2, ST10F273Z4, ST10F276Z5； ST10传统闪存系列：ST10F168S, ST10F269, ST10F269Z1, ST10F269Z2； ST10 ROMless 系列：ST10R172L, ST10R272L, ST10R167-Q； STR7系列ARM芯片解密： STR750F：STR755FV2, STR755FV1, STR755FV0, STR755FR2, STR755FR1, STR755FR0, STR752FR2, STR752FR1, STR752FR0, STR751FR2, STR751FR1, STR751FR0, STR750FV2, STR750FV1, STR750FV0； STR71x：STR715FR0, STR712FR2, STR712FR0, STR711FR2, STR712FR1, STR711FR1, STR711FR0, STR710RZ, STR710FZ2, STR710FZ1； STR73xF：STR736FV2, STR736FV1, STR736FV0, STR735FZ2, STR735FZ1, STR731FV2, STR731FV1, STR731FV0, STR730FZ2, STR730FZ1； STR9系列ARM芯片解密： STR91xFA：STR912FAZ44, STR912FAZ42, STR912FA W44, STR912FA W42, STR911FA W44, STR911FA W42, STR911FAM44, STR911FAM42, STR910FAZ32, STR910FA W32, STR910FAM32；
压电式MEMS仿生结构矢量水听器设计 开题报告
毕业设计开题报告 学生姓名：学号： 学院： 专业： 设计(论文)题目：压电式MEMS仿生结构矢量水听器 封装及性能测试研究指导教师: 2013年12月10日
开题报告填写要求 1．开题报告作为毕业设计（论文）答辩委员会对学生答辩资格审查的依据材料之一。此报告应在指导教师指导下，由学生在毕业设计（论文）工作前期内完成，经指导教师签署意见及所在专业审查后生效； 2．开题报告内容必须用按教务处统一设计的电子文档标准格式（可从教务处网页上下载）打印，禁止打印在其它纸上后剪贴，完成后应及时交给指导教师签署意见； 3．学生写文献综述的参考文献应不少于15篇（不包括辞典、手册）。文中应用参考文献处应标出文献序号，文后“参考文献”的书写，应按照国标GB 7714—87《文后参考文献著录规则》的要求书写，不能有随意性； 4．学生的“学号”要写全号（如020*******,为10位数），不能只写最后2位或1位数字； 5. 有关年月日等日期的填写，应当按照国标GB/T 7408—94《数据元和交换格式、信息交换、日期和时间表示法》规定的要求，一律用阿拉伯数字书写。如“2004年3月15日”或“2004-03-15”； 6. 指导教师意见和所在专业意见用黑墨水笔工整书写，不得随便涂改或潦草书写。
毕业设计开题报告
矢量水听器由于体积小、重量轻、布放方便等特点，在实际应用中已经受到重视。近年来，在MEMS仿生器件研究方面，国外已有多家研究机构通过模仿鱼类侧线器官、蟋蟀的听觉纤毛等，设计并制造出了多种压电式、压阻式以及电容式的MEMS纤毛仿生微传感器，如德国的Nest-erov和Brand于2005年研制出了压阻式MEMS仿生微探测器，美国伊利诺斯州立大学微米纳米技术研究中心的Chen等于2006年通过模仿鱼类的侧线器官工作原理，研制出了纤毛式MEMS仿生微流量传感器。荷兰的Krijnen等在2006年通过模仿蟋蟀的听觉纤毛，制作出了纤毛式仿生微声传感器[5]。 目前，在美国和俄罗斯，性能稳定的矢量水听器已经进入了工程应用阶段。美国在SURTASS系统中已经应用矢量水听器，解决了左右舷模糊问题；前苏联利用其研制的矢量水听器托线阵，系统地研究了矢量水听器托线阵的姿态、拖拽速度和流噪声对矢量水听器检测性能的影响。国外的纤毛仿生传感器也主要为微触觉传感器或微流量传感器，关于纤毛式的仿生MEMS水声传感器还未见报道[6]。 1.2.2 国内本课题的发展现状及前景 国内从“八.五”期间开始矢量水听器的研究，并取得了丰硕的成果，先后研发了以双迭片为敏感元件的不动外壳型矢量水听器和以加速度计为敏感元件的同振球型矢量水听器。十年来，我国在矢量水听器的研制方面取得了长足的进步，先后研制出多种结构具有自主产权的矢量水听器，包括动圈式矢量水听器、悬臂梁式多维测振传感器、压电圆盘弯曲式同振型矢量水听器以及中、高频二维柱形、三维球型矢量水听器等，从而实现了水声测量中不同场合的不同需求[7]。 目前，国内关于纤毛式仿生MEMS传感器的研究还比较少，主要研究成果是中北大学微米纳米研究中心设计并制造的压阻式MEMS仿生结构矢量水听器，如图1所示[8]。该水听器是通过模仿鱼类侧线器官的神经丘感觉器，完成了以压敏电阻为敏感单元的水声传感器仿生组装设计；利用新型精巧的仿生结构和压阻敏感机理设计制作新型的矢量水声传感器；利用MEMS批量制造技术，实现矢量水声传感器的小型化和一致性；结合MEMS工艺和组装工艺技术，解决复杂结构的仿生制造问题。该矢量水声传感器的低频特性、灵敏度、小尺寸以及水声传感器的一致性等方面带来好处，为水声传感器的设计提供一种新方法[9]。
ST意法半导体代理
意法半导体-万联芯城全国供应，电子元器件采购网，就找万联芯城，万联芯城专售原装进口现货电子元器件，与国内外原厂达成深度合作，坐拥三千平方米现代化仓库，解决终端生产研发物料问题，专为客户节省采购成本。 点击进入万联芯城 意法半导体代理_ST代理是一家法国 - 意大利跨国电子和半导体制 造商，总部位于瑞士日内瓦。它通常被称为意法半导体代理_ST代
理，它是欧洲大的基于收入的半导体芯片制造商。虽然意法半导体代理_ST代理公司总部和EMEA地区总部设在日内瓦，但控股公司意法半导体代理_ST代理 N.V.在荷兰阿姆斯特丹注册。 意法半导体代理_ST代理的美国总部位于德克萨斯州的Coppell。亚太地区总部位于新加坡，日本和韩国业务总部位于东京。大中华区的公司总部位于上海。 意法半导体代理_ST代理成立于1987年，由意大利的半导体公司SGS Microelettronica（SocietàGeneraleSemiconduttori）和法国Thomson的半导体部门Thomson Semiconducteurs合并而成。在合并时，意法半导体代理_ST代理被称为SGS-THOMSON，但在Thomson SA 作为所有者撤回后于1998年5月取得现在的名称-意法半导体代理 _ST代理。 SGS Microelettronica和Thomson Semiconducteurs都是历史悠久的半导体公司。 SGS Microelettronica始于1972年，此前两家公司合并： ATES（Aquila Tubi e Semiconduttori），一家真空管和半导体制造商，总部位于阿布鲁兹市的拉奎拉市，于1961年更名为Azienda
光纤水听器综述
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话说宝玉在林黛玉房中说"耗子精"，宝钗撞来，讽刺宝玉元宵不知"绿蜡"之典，三人正在房中互相讥刺取笑。 杨宪益：Pao-yu，as we saw, was in Tai-yu?s room telling her the story about the rat spirits when Pao-chai burst in and teased him for forgetting the “green wax” allusion on the night of the Feast of Lanterns. 霍克斯: We have shown how Bao-yu was in Dai-yu?s room telling her the story of the magic mice; how Bao-Chai burst in on them and twitted Bao-yu with his failure to remember the …green wax? allusion on the night of the Lantern Festival; and how the three of them sat teasing each other with good-humored banter. 对比分析：杨宪益和霍克斯在翻译“耗子精”采用来了不同的处理方法，前者使用了异化”rat spirits”，后者用的是归化法”magic mice”,使用归化法更受英美读者的亲乃。但是二者同时采用了增译法，增添了the story，原文并没有。在翻译“宝玉不知绿烛之典”的“不知”，英文1用的是“forgetting”，而译文2用的是“with failure to ”，显然译文2更符合英美的表达习惯。 那宝玉正恐黛玉饭后贪眠，一时存了食，或夜间走了困，皆非保养身体之法。幸而宝钗走来，大家谈笑，那林黛玉方不欲睡，自己才放了心。 杨宪益：Pao-yu felt relieved as they laughed and made fun of each other, for he had feared that sleeping after lunch might give Tai-yu indigestion or insomnia that night, and so injure her health. Luckily Pao-chai?s arrival and the lively conversation that followed it had woken Tai-yu up. 霍克斯: Bao-yu had been afraid that by sleeping after her meal Dai-yu would give herself indigestion or suffer from insomnia through being insufficiently tired when she went to bed at night, but Bao-chai?s arrival and the lively conversation that followed it banished all Dai-yu?s desire to sleep and enabled him to lay aside his anxiety on her behalf. 对比分析：译文一对原文语序进行了调整，先说了“放心”，再说“担心”，但并不如不调整顺序的逻辑强。译文二只是用了一个“but”就把原文意思分层了两层，逻辑更加清晰，符合西方人注重逻辑的习惯。原文中的“谈笑”是动词，而两个译文版本都是译的“the lively conversation”，是名词，体现了汉语重动态，英文重静态的特点。 忽听他房中嚷起来，大家侧耳听了一听，林黛玉先笑道："这是你妈妈和袭人叫嚷呢。那袭人也罢了，你妈妈再要认真排场她，可见老背晦了。" 杨宪益：Just then, a commotion broke out in Pao-yu?s apartments and three of th em pricked up their ears. “It?s your nanny scolding Hai-jen,” announced Tai-yu. “There?s nothing wrong with Hai-jen, yet your nanny is for ever nagging at her. Old age has befuddled her.”
用MSp430进行微功耗数据采集
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《傲慢与偏见》译文对比分析
《傲慢与偏见》（节选一） Pride and Prejudice by Jane Austen (An Except from Chapter One) 译文对比分析 节选文章背景：小乡绅贝内特有五个待字闺中的千金，贝内特太太整天操心着为女儿物色称心如意的丈夫。新来的邻居宾利(Bingley)是个有钱的单身汉，他立即成了贝内特太太追猎的目标。 1.It’s a truth u niversally acknowledged, that a single man in possession of a good fortune, must be in want of a wife. 译文一：凡是有钱的单身汉，总想娶位太太，这已经成了一条举世公认的道理。译文二：有钱的单身汉总要娶位太太，这是一条举世公认的真理。 2.However little known the feelings or views of such a man may be on his first entering a neighborhood, this truth is so well fixed in the minds of the surrounding families that he is considered as the rightful property of some one or other of their daughters. 译文一：这样的单身汉，每逢新搬到一个地方，四邻八舍虽然完全不了解他的性情如何，见解如何，可是，既然这样的一条真理早已在人们心中根深蒂固，因此人们总是把他看作是自己某一个女儿理所应得的一笔财产。 译文二：这条真理还真够深入人心的，每逢这样的单身汉新搬到一个地方，四邻八舍的人家尽管对他的性情见识一无所知，却把他视为某一个女儿的合法财产。 3.”My dear Mr. benne” said his lady to him one day ,”have you heard that nether field park is let at last?” 译文一：有一天班纳特太太对她的丈夫说：“我的好老爷，尼日斐花园终于租出去了，你听说过没有？” 译文二：“亲爱的贝特先生”一天，贝纳特太太对先生说：“你有没有听说内瑟费尔德庄园终于租出去了：” 4.Mr. Bennet replied that he had not. 译文一：纳特先生回答道，他没有听说过。 译文二：纳特先生回答道，没有听说过。 5.”But it is,” returned she:” for Mrs. long has just been here, and she t old me all about it.” 译文一：“的确租出去了，”她说，“朗格太太刚刚上这来过，她把这件事情的底细，一五一十地都告诉了我。” 译文二：“的确租出去了，”太太说道。“朗太太刚刚来过，她把这事一五一十地全告诉我了。”
意法半导体公司产品导购手册
意法半导体 意法半导体 （ ST ）公司成立于 1987 年，是意大利 SGS 半导体公司和法国汤姆逊半导体合并后的新企业，公司总部设在瑞士日内瓦。公司创立目标是在亚微米时代挤身于世界一流的半导体公司之列。新公司采纳并实施一个锐意进取的公司发展战略，将大量的资金投入到产品技术的研发活动中，与业绩优异的客户和享誉全球的学术机构建立战略联盟，在主要的经济地区建立集研发、制造和销售于一体的业务网络，力争成为世界上生产效率最高的制造公司之一。 ST 是世界上最大的半导体公司之一， 2006 年净营业收入 98.5 亿美元。 ST 还是多个领域的市场领导者，例如：据初步的工业数据显示， ST 是世界第五大半导体公司，模拟产品、模拟专用集成电路（ AASIC ）和模拟专用标准产品（ ASSP ）的销售额居市场领先水平。 ST 是第一大手机相机模块供应商和第二大分立器件供应商，第三大 NOR 闪存供应商，在汽车电子、工业用产品和无线应用领域，市场排名居第三。 ST 同时是全球第一大的机顶盒和电源管理芯片制造商。在中国市场上， ST 是 2005 年第三大半导体供应商。 相关产品 ?S T7单片机 ?S TM8单片机 ?S TM32单片机 ?I GBT ?功率放大器
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《乡愁》两个英译本的对比分析
《乡愁》两个英译本的对比分析 曹菊玲 （川外2013级翻译硕士教学1班文学翻译批评与鉴赏学期课程论文） 摘要：余光中先生的《乡愁》是一首广为人知的诗歌，曾被众多学者翻译成英文，本文将对赵俊华译本和杨钟琰译本进行对比分析，主要从原作的分析、译文的准确性、译文风格以及对原文意象的把握入手进行赏析，指出两译本的不足和精彩之处。 关键词：《乡愁》；原诗的分析；准确性；风格；意象的把握 1.原诗的分析 作者余光中出生于大陆，抗战爆发后在多地颠沛流离，最后22岁时移居台湾。20多年都未回到大陆，作者思乡情切，于上世纪70年代创作了这首脍炙人口的诗歌，但是当时大陆与台湾关系正处于紧张时期，思而不得的痛苦与惆怅包含于整首诗中。 全诗为四节诗，节与节之间完全对称，四句一节，共十六句，节奏感、韵律感很强，读起来朗朗上口。而且这首诗语言简洁，朴实无华，但是却表达了深刻的内涵。从整体上看，作者采取层层递进的方式，以时空的隔离和变化来推进情感的表达，最后一句对大陆的思念，一下子由个人哀愁扩大到国家分裂之愁，因而带有历史的厚重感。 【原诗】 乡愁 余光中 小时候／乡愁是一枚小小的邮票／我在这头／母亲在那头 长大后／乡愁是一张窄窄的船票／我在这头／新娘在那头 后来啊／乡愁是一方矮矮的坟墓／我在外头／母亲在里头 而现在／乡愁是一湾浅浅的海峡／我在这头／大陆在那头 【译诗】 (1) 赵俊华译 Homesick As a boy, I was homesick for a tiny stamp, —I was here, Mom lived alone over there. When grow up, I was homesick for a small ship ticket. —I was here,
意法半导体(ST)新的32位系列Cortex-M3内核微控制器重塑MCU市场
意法半导体（ST)新的32位系列Cortex-M3内核微控制器重塑MCU 市场 --STM32 MCU系列大幅度提高了嵌入式系统的性价比和功耗水准 中国，2007年6月11日--世界领先的半导体制造厂商意法半导体（纽约证券交易所：STM）今天推出一个新的32位微控制器系列产品，新产品所用微处理器是ARM公司为要求高性能（1.25 Dhrystone MIPS/MHz）、低成本、低功耗的嵌入式应用专门设计的ARM ?Cortex?-M3内核。STM32系列产品得益于Cortex-M3在架构上进行的多项改进，包括提升性能的同时又提高了代码密度的Thumb-2指令集和大幅度提高中断响应的紧耦合嵌套向量中断控制器，所有新功能都同时具有业界最优的功耗水平。ST是Cortex-M3内核开发项目的一个主要合作方，现在是第一个推出基于这个内核的主要微控制器厂商。 以实现出色的性能和能效为设计目标，同时保留开放工业标准的ARM架构和开发环境的优点，STM32系列产品按性能又分成两个不同的系列：STM32F103“增强型”系列和 STM32F101“基本型”系列。增强型系列时钟频率达到72MHz，是同类产品中性能最高的产品；基本型时钟频率为36MHz，以16位产品的价格得到比16位产品大幅提升的性能，是16位产品用户的最佳选择。两个系列都内置32K到128K的闪存，不同的是SRAM的最大容量和外设接口的组合。时钟频率72MHz时，从闪存执行代码，STM32功耗仅36mA，是32位市场上功耗最低的产品，相当于0.5mA/MHz。
Cortex-M3内核主打存储器和处理器的尺寸对产品成本影响极大的各种应用市场，是针对这些市场的低成本需求，专门开发设计的微处理器内核。Cortex-M3内核增强了芯片上集成的各种功能，包括把中断之间延迟降到6个CPU周期的嵌套向量中断控制器、允许在每一个写操作中修改单个数据位的独立位操作、分支指令预测、单周期乘法、硬件除法和高效的 Thumb 2指令集，这些改良技术使Cortex-M3内核具有优异的性能、代码密度、实时性和低功耗。 STM32采用2.0到3.6V电源，当复位电路工作时，在待机模式下最低功耗2μA，因此最适合电池供电的应用设备。其它省电功能包括一个集成的实时时钟、一个专用的32kHz振荡器和四种功率模式，其中实时时钟含有一个电池操作专用引脚。 “直到现在，16位和32位的设计工程师还要面对很多困难的选择，例如，他们必须在性能、成本、功耗等因素之间做出折衷和取舍，决定使用业界标准还是使用某一公司独有的平台，”ST微控制器产品部总经理Jim Nicholas表示，“通过消除这些需要折衷的因素，STM32走在了融合16位和32位微控制器市场的前列。” 在性能方面，STM32系列的处理速度比同级别的基于ARM7TDMI的产品快30%，换句话说，如果处理性能相同，STM32产品功耗比同级别产品低75%。同样地，使用新内核的Thumb 2指令集，设计人员可以把代码容量降低45%，几乎把应用软件所需内存容量降低了一半。此外，根据Dhrystones和其它性能测试结果，STM32的性能比最好的16位架构至少高出一倍。 新产品提供多达128KB的嵌入式闪存、20KB的RAM和丰富的外设接口，包括两个12位模数转换器（1微秒的转换时间）、三个USART、两个SPI（18MHz主/从控制器）、两个I2C、三个16位定时器（每个定时器有4个输入捕获模块/4个输出比较器/4个PWM控制器），以及一个专门为电机控制向量驱动应用设计的内嵌死区时间控制器的6-PWM定时器、USB、CAN和7个DMA通道。内置复位电路包括上电复位、掉电复位和电压监控器，以及一个可用作主时钟的高精度工厂校准的8MHz阻容振荡器、一个使用外部晶振的4-16MHz振荡器和两个看门狗。因为集成度如此之高，除一个电源外，LQFP100封装产品的最小系统只需要7个电容器。 除工业可编程逻辑控制器（PLC）、家电、工业及家用安全设备、消防和暖气通风空调系统等传统应用，智能卡和生物测定等消费电子/PC应用外，新的STM32系列还特别适合侧重低功耗的设备，如血糖和血脂监测设备。 “融低功耗、易用性和低成本于一身的STM32系列克服了现有的阻碍32位微控制器推广应用的全部问题，”Nicholas表示，“我们相信STM32将满足每一个设计人员的期望。未来的STM32系列产品将扩充已有的功能选项，达到512KB闪存和64KB SRAM以及更多的功能。” STM32系列产品配有成套的ST和第三方的开发工具。ST提供一个评估板、USB开发工具包和一个免费的软件库。Hitex、IAR、Keil和Raisonance不久将在经过验证的基于ARM 内核的工具解决方案的基础上推出入门级开发工具。目前，Hitex、IAR、Keil、Raisonance 和Rowley的工具链支持STM32。
落花生两英译本的对比分析
《落花生》两英译本的对比分析 【摘要】本文对张培基先生和刘士聪先生对《落花生》的英译本从接受美学的角度进行了对比分析。通过分析原文的写作目的，风格和语言特点从而对翻译的分析打下良好基础。举例对翻译的段落进行了对比分析，反映了译者的期待视野影响翻译目的，职业经历和翻译的基本观点影响期待视野。这一点对于文本不确定性和语义空白点的具体化十分重要。 【关键词】《落花生》；张培基；刘士聪；接受美学；翻译对比 一、原文的介绍 《落花生》是中国著名作家许地山创作的一篇具有深远意义的散文。他回忆了童年时发生的一件小事。父亲通过一件关于花生的小事讲述了生活哲理。 原文具有以下几个功能： 1、信息功能：它描述了童年发生的一件事及花生的特点和用途。 2、审美功能：文章的语言简单朴素清新自然。语言特点，内容和风格相得益彰，形成了浓厚的艺术吸引力。 3、表达功能：这篇散文表达了作者崇高的思想，即便是在动荡浑浊的旧时代，还应保持个人节操。 4、祈使功能：虽然描写的是不起眼的花生，却在字里行间向大家传递了人生哲学。那就是“那么，人要做有用的人，不要做伟大、体面的人了。” 二、两英译本对比分析 张先生和刘先生在翻译时都保留了原文的风格和特点。但他们的翻译风格还是有些不同的。 他们的期待视野影响其翻译目的。他们的职业经历影响他们翻译期待视野。张先生和刘先生都曾在出版社做过编辑，都潜心研究翻译事业。但是不同的是刘先生还有翻译教学的经历。和张先生相比，他更算的上是一个翻译教育学者。他投身于翻译教学和其他英语相关的学科研究中。从以上可以推断出，可能刘先生在翻译过程中遵循的规则更加严格，并且会更加的客观，也就是说学术的客观性会比较多，在翻译中自己主观理解的加入可能较少。这里有一个例子。原文：“那晚上的天色不大好，…”刘先生译文：“The weather was not very good that night but，….”张先生译文：“It looked like rain that evening，….”而“天色不太好”并不代表就是要下雨了。虽然对于这一句的翻译并不影响整体，但是作为一个翻译来说，并不应该加入过多的理所当然的想象。 除了翻译家的职业经历会影响他们的翻译表现和态度，他们对于翻译的基本看法，也会影响翻译工作。刘先生认为翻译的最高境界是对原文韵味的再现。译作“韵味”就是原作的艺术内涵通过译文准确而富有文采的语言表达时所蕴含的艺术感染力，这能引起读者的美感共鸣。除此之外，刘先生还强调要把译文作为独立的文本来看待。具体说来就是对译文美感和韵味的展现虽是从词句入手的，同时还应注意译文包括内容和风格的整体效果。当两者有了矛盾，要变通前者来适应后者。从以上不难看出，刘先生在翻译时非常注重两方面，一是对原文韵味的保留，也就是原文内容中所蕴含的艺术吸引力的保留，另一方面就是对翻译整体效果的追求要超越对词语句子的效果的追求。
译文对比评析从哪些方面
译文对比评析从哪些方面 匆匆英译文对比赏析 （1）匆匆 译文1：Transient Days 译文2：Rush （2）燕子去了，有再来的时候；杨柳枯了，有再青的时候；桃花谢了，有再开的时候。 译文1：If swallows go away, they will come back again. If willows wither, they will turn green again. If peach blossoms fade, they will flower again. 译文2：Swallows may have gone, but there is a time to return; willow trees may have died back, but there is a time of regreening; peach blossoms may have fallen, but they will bloom again.
（3）但是，聪明的，你告诉我，我们的日子为什么一去不复返呢?——是有人偷了他们罢：那是谁?又藏在何处呢?是他们自己逃走了罢：现在又到了哪里呢? 译文1：But, tell me, you the wise, why should our days go by never to return? Perhaps they have been stolen by someone. But who could it be and where could he hide them? Perhaps they have just run away by themselves. But where could they be at the present moment? 译文2：Now, you the wise, tell me, why should our days leave us, never to return? ----If they had been stolen by someone, who could it be? Where could he hide them? If they had made the escape themselves, then where could they stay at the moment? （4）我不知道他们给了我多少日子；但我的手确乎是渐渐空虚了。译文1：I don’t know how many days I am entitled to