Developing advanced stealth devices to cope with radar-infrared(IR)fusion detection and diverse application scenarios is increasingly demanded,which faces significant challenges due to conflicting microwave and IR clo...Developing advanced stealth devices to cope with radar-infrared(IR)fusion detection and diverse application scenarios is increasingly demanded,which faces significant challenges due to conflicting microwave and IR cloaking mechanisms and functional integration limitations.Here,we propose a multiscale hierarchical structure design,integrating wrinkled MXene IR shielding layer and flexible Fe_(3)O_(4)@C/PDMS microwave absorption layer.The top wrinkled MXene layer induces the intensive diffuse reflection effect,shielding IR radiation signals while allowing microwave to pass through.Meanwhile,the permeable microwaves are assimilated into the bottom Fe_(3)O_(4)@C/PDMS layer via strong magneto-electric synergy.Through theoretical and experimental optimization,the assembled stealth devices realize a near-perfect stealth capability in both X-band(8–12 GHz)and long-wave infrared(8–14μm)wavelength ranges.Specifically,it delivers a radar cross-section reduction of−20 dB m^(2),a large apparent temperature modulation range(ΔT=70℃),and a low average IR emissivity of 0.35.Additionally,the optimal device demonstrates exceptional curved surface conformability,self-cleaning capability(contact angle≈129°),and abrasion resistance(recovery time≈5 s).This design strategy promotes the development of multispectral stealth technology and reinforces its applicability and durability in complex and hostile environments.展开更多
Because of global climate change, it is necessary to add forest biomass estimation to national forest resource monitoring. The biomass equations developed for forest biomass estimation should be compatible with volume...Because of global climate change, it is necessary to add forest biomass estimation to national forest resource monitoring. The biomass equations developed for forest biomass estimation should be compatible with volume equations. Based on the tree volume and aboveground biomass data of Masson pine （Pinus massoniana Lamb.） in southern China, we constructed one-, two- and three-variable aboveground biomass equations and biomass conversion functions compatible with tree volume equations by using error-in-variable simultaneous equations. The prediction precision of aboveground biomass estimates from one variable equa- tion exceeded 95%. The regressions of aboveground biomass equations were improved slightly when tree height and crown width were used together with diameter on breast height, although the contributions to regressions were statistically insignificant. For the biomass conversion function on one variable, the conversion factor decreased with increasing diameter, but for the conversion function on two variables, the conversion factor increased with increasing diameter but decreased with in- creasing tree height.展开更多
Cold acclimation is associated with many metabolic changes that lead to an increase of freezing tolerance. In order to investigate the biochemical process of cold acclimation in Ammopiptanthus mongolicus, seedlings we...Cold acclimation is associated with many metabolic changes that lead to an increase of freezing tolerance. In order to investigate the biochemical process of cold acclimation in Ammopiptanthus mongolicus, seedlings were acclimated at 2℃ under 16-h photoperiod （150 μmol·m^-2·s^-1 photosynthetically active radiation） for 14 d. Freezing tolerance in seedlings increased after 14 d of cold-hardening. Contents of protein, proline and solute carbohydrate in cotyledon increased after cold acclimation. Patterns of isozymes of superoxide dismutase （SOD）, peroxidase, catalase and polyphenol oxidase （PPO） were investigated. The activities of SOD, peroxidase and PPO in cold acclimated plants were increased during cold-hardening. We deduced that compatible solutes and antioxidant enzymes play important roles in development of freezing tolerance during cold acclimation in this evergreen woody plant.展开更多
The rapid development and widespread application of lithium-ion batteries(LIBs) have increased demand for high-safety and high-performance LIBs. Accordingly, various additives have been used in commercial liquid elect...The rapid development and widespread application of lithium-ion batteries(LIBs) have increased demand for high-safety and high-performance LIBs. Accordingly, various additives have been used in commercial liquid electrolytes to severally adjust the solvation structure of lithium ions, control the components of solid electrolyte interphase, or reduce flammability. While it is highly desirable to develop low-cost multifunctional electrolyte additives integrally that address both safety and performance on LIBs, significant challenges remain. Herein, a novel phosphorus-containing organic small molecule, bis(2-methoxyethyl) methylphosphonate(BMOP), was rationally designed to serve as a fluorine-free and multifunctional additive in commercial electrolytes. This novel electrolyte additive is low-toxicity,high-efficiency, low-cost, and electrode-compatible, which shows the significant improvement to both electrochemical performance and fire safety for LIBs through regulating the electrolyte solvation structure, constructing the stable electrode-electrolyte interphase, and suppressing the electrolyte combustion. This work provides a new avenue for developing safer and high-performance LIBs.展开更多
Solid-state lithium metal batteries are promising next-generation batteries for both micro-scale integrated electronic devices and macro-scale electric vehicles.However,electrochemical incompatibility between electrol...Solid-state lithium metal batteries are promising next-generation batteries for both micro-scale integrated electronic devices and macro-scale electric vehicles.However,electrochemical incompatibility between electrolyte and electrodes causes continuous performance degradation.Here,we report a unique design of a double-layer composite solid-state electrolyte(D-CSE),where each layer,composed of both polymer and ceramics,is electrochemically compatible with its contacting electrode(Li anode or LiCoO_(2)cathode).The D-CSE has a small thickness(50μm),high thermal stability(up to 160℃ without noticeable deformation),and good flexibility even at a high ceramics content(66.7 wt%).Large-area selfstanding film can be obtained by a facile coating route.The electrolyte/electrode interface can be further enhanced via forming a soft interface by in-situ polymerization.Quasi-solid-state Li|D-CSE|LiCoO_(2)coin cells with the cathode-supported D-CSE can deliver a high initial discharge capacity of 134 mAh g^(-1) and a high capacity retention of 83%after 200 cycles at 0.5 C and 60℃.Quasi-solid-state Li|D-CSE|LiCoO_(2)pouch cells(designed capacity 8.6 mAh)with the self-standing D-CSE have a high retention of80%after 180 cycles at 2 mA charge and 4 mA discharge.At a high cathode loading(19.1 mg cm^(-2)),the Li|D-CSE|LiCoO_(2)pouch cell still can be stably cycled,and can withstand abuse tests of folding,cutting and nail penetration,indicating practical applications of the D-CSE.展开更多
Peer-to-peer(P2P)energy trading refers to a type of decentralized transaction,where the energy from distributed energy resources is directly traded between peers.A key challenge in peer-to-peer energy trading is desig...Peer-to-peer(P2P)energy trading refers to a type of decentralized transaction,where the energy from distributed energy resources is directly traded between peers.A key challenge in peer-to-peer energy trading is designing a safe,efficient,and transparent trading model and operating mechanism.In this study,we consider a P2P trading environment based on blockchain technology,where prosumers can submit bids or offers without knowing the reports of others.We propose an Arrow-d’Aspremont-Gerard-Varet(AGV)-based mechanism to encourage prosumers to submit their real reserve price and determine the P2P transaction price.We demonstrate that the AGV mechanism can achieve Bayesian incentive compatibility and budget balance.Kernel density estimation(KDE)is used to derive the prior distribution from the historical bid/offer information of the agents.Case studies are carried out to analyze and evaluate the proposed mechanism.Simulation results verify the effectiveness of the proposed mechanism in guiding agents to report the true reserve price while maximizing social welfare.Moreover,we discuss the advantages of budget balance for decentralized trading by comparing the Vickrey-Clarke-Groves(VCG)and AGV mechanisms.展开更多
A thin radar-infrared stealth-compatible structure with reflectivity below -10 dB in the whole radar X wave band and infrared emissivity less than 0.3 in the infrared region of 8μm-14 μm is reported. The designed st...A thin radar-infrared stealth-compatible structure with reflectivity below -10 dB in the whole radar X wave band and infrared emissivity less than 0.3 in the infrared region of 8μm-14 μm is reported. The designed stealth-compatible structure consists of metallic frequency selective surface （MFSS）, resistive frequency selective surface （RFSS）, and metal backing from the top down, and it is only 2. l-mm thick. The MFSS is made up of some divided low infrared emissivity metal copper films, and the RFSS consists of a capacitive array of square resistive patches. They are placed close together, working as an admittance sheet because of a mutual influence between them, and the equivalent admittance sheet greatly reduces the thickness of the whole structure. The proposed stealth-compatible structure is verified both by simulations and by experimental results. These results indicate that our proposed stealth-compatible structure has potential applications in stealth fields.展开更多
Rate Compatible Modulation(RCM)is an efficient technique for high spectral efficiency seamless transmission over highly dynamic wireless channels.However,its high decoding complexity at the receiver prevents it from b...Rate Compatible Modulation(RCM)is an efficient technique for high spectral efficiency seamless transmission over highly dynamic wireless channels.However,its high decoding complexity at the receiver prevents it from being applied in scenarios where computation resources are limited.To alleviate this problem,an RCM with variable weight sets(RCM-VWS)was presented in the literature to significantly reduce its complexity by employing weight sets of different complexities for channels at different signal-tonoise-ratio(SNR).However,RCM-VWS has to introduce an undesired feedback channel for the transmission of SNR information that is estimated at the receiver and transmitted back to the transmitter for weight set selection.To achieve a low computational complexity while avoiding feedback transmission at the same time,a novel RCM scheme with hybrid weight set(RCM-HWS)is introduced in this paper.A low complexity of decoding is allowed by gradually reducing the complexity of weight sets based on the number symbols already sent.It also avoids the feedback of SNRs since we can deduce SNRs from the number of the symbols transmitted and use a hybrid weight set we have designed.The theoretical analysisand simulation results show that the proposed scheme has the advantages of low demodulation complexity and not requiring feedback channel while maintaining the same transmission throughput as that of the conventional RCM.Therefore,the proposed scheme has a wider range of applications,especially in the case that feedback channel is not available.展开更多
A radar-infrared compatible stealth surface is designed and analyzed.Without modifying the radar absorbing material(RAM),the design can theoretically achieve radar-infrared compatibility and broadband radar absorption...A radar-infrared compatible stealth surface is designed and analyzed.Without modifying the radar absorbing material(RAM),the design can theoretically achieve radar-infrared compatibility and broadband radar absorption through surface patterns and structures.A transmission-line-based model(TLM)is developed to analyze the radar absorbing performance of the surface.Optimization of the structure geometries is conducted aiming to maximize the-10 d B absorption bandwidth in 2–18 GHz.Surface with optimized structure geometries exhibits a superior absorption bandwidth,more than twice the bandwidth of the original 1.5 mm RAM slab,while maintaining a relatively low infrared emissivity.展开更多
We have developed two 474 THz(633 nm)new iodine stabilized He-Ne lasers with compatible system of third and fifth harmonic locking.The frequency stability is 1.0×10-11/ 1s and 3.5×10-12 / 10s with third harm...We have developed two 474 THz(633 nm)new iodine stabilized He-Ne lasers with compatible system of third and fifth harmonic locking.The frequency stability is 1.0×10-11/ 1s and 3.5×10-12 / 10s with third harmonic locking,and corresponding values are 1.3×10-11/1s and 4.0×10-12/ 10s with fifth harmonic locking.We found that the frequency difference between the same component with third and fifth harmonic locking are from 5 kHz to SO kHz.Our experiment and analysis indicate that the center of fifth harmonic signals is closer to the Lorentzian center in iodine absorption component than one of the third harmonic signals,and the reproducibility with fifth harmonic locking is also better than one with third harmonic locking.展开更多
We present a micro-Pirani vacuum gauge using the low-resistivity monocrystal silicon as the heaters and heat sinks fabricated by the post complementary metal oxide semiconductor （CMOS） microelectromechanical system ...We present a micro-Pirani vacuum gauge using the low-resistivity monocrystal silicon as the heaters and heat sinks fabricated by the post complementary metal oxide semiconductor （CMOS） microelectromechanical system （MEMS） process. The metal interconnection of the device is fabricated by a 0.5 μm standard CMOS process on 8-inch silicon wafer. Then, a SiO2-Si low-temperature fusion bonding is developed to bond the CMOS wafer and the MEMS wafer, with the electrical connection realized by the tungsten through silicon via process. Wafer- level A1Ge euteetic bonding is adopted to package the Pirani gauge in a non-hermetic cavity to protect the gauge from being damaged or contaminated in the dicing and assembling process, and to make it suitable for actual applications. To increase the accuracy of the test and restrain negative influence of temperature drift, the Wheatstone bridge structure is introduced. The test results show that before capping, the gauge has an average sensitivity of 1.04 × 104 K.W-1Torr-1 in dynamic range of 0.01 20 Torr. After capping, the sensitivity of the gauge does not decrease but increases to 1.12 × 104 K.W-1 Torr-1.展开更多
In this paper, we propose a new method to derive a family of regular rate-compatible low-density parity-check（RC-LDPC） convolutional codes from RC-LDPC block codes. In the RC-LDPC convolutional family, each extended...In this paper, we propose a new method to derive a family of regular rate-compatible low-density parity-check（RC-LDPC） convolutional codes from RC-LDPC block codes. In the RC-LDPC convolutional family, each extended sub-matrix of each extended code is obtained by choosing specified elements from two fixed matrices HE1K and HE1K, which are derived by modifying the extended matrices HE1 and HE2 of a systematic RC-LDPC block code. The proposed method which is based on graph extension simplifies the design, and prevent the defects caused by the puncturing method. It can be used to generate both regular and irregular RC-LDPC convolutional codes. All resulted codes in the family are systematic which simplify the encoder structure and have maximum encoding memories which ensure the property. Simulation results show the family collectively offer a steady improvement in performance with code compatibility over binary-input additive white Gaussian noise channel（BI-AWGNC）.展开更多
基金financial support from the National Nature Science Foundation of China(No.52273247)the National Science and Technology Major Project of China(J2019-VI-0017-0132).
文摘Developing advanced stealth devices to cope with radar-infrared(IR)fusion detection and diverse application scenarios is increasingly demanded,which faces significant challenges due to conflicting microwave and IR cloaking mechanisms and functional integration limitations.Here,we propose a multiscale hierarchical structure design,integrating wrinkled MXene IR shielding layer and flexible Fe_(3)O_(4)@C/PDMS microwave absorption layer.The top wrinkled MXene layer induces the intensive diffuse reflection effect,shielding IR radiation signals while allowing microwave to pass through.Meanwhile,the permeable microwaves are assimilated into the bottom Fe_(3)O_(4)@C/PDMS layer via strong magneto-electric synergy.Through theoretical and experimental optimization,the assembled stealth devices realize a near-perfect stealth capability in both X-band(8–12 GHz)and long-wave infrared(8–14μm)wavelength ranges.Specifically,it delivers a radar cross-section reduction of−20 dB m^(2),a large apparent temperature modulation range(ΔT=70℃),and a low average IR emissivity of 0.35.Additionally,the optimal device demonstrates exceptional curved surface conformability,self-cleaning capability(contact angle≈129°),and abrasion resistance(recovery time≈5 s).This design strategy promotes the development of multispectral stealth technology and reinforces its applicability and durability in complex and hostile environments.
基金the National Biomass Modeling Program for Continuous Forest Inventory(NBMP-CFI) funded by the State Forestry Administration of China
文摘Because of global climate change, it is necessary to add forest biomass estimation to national forest resource monitoring. The biomass equations developed for forest biomass estimation should be compatible with volume equations. Based on the tree volume and aboveground biomass data of Masson pine （Pinus massoniana Lamb.） in southern China, we constructed one-, two- and three-variable aboveground biomass equations and biomass conversion functions compatible with tree volume equations by using error-in-variable simultaneous equations. The prediction precision of aboveground biomass estimates from one variable equa- tion exceeded 95%. The regressions of aboveground biomass equations were improved slightly when tree height and crown width were used together with diameter on breast height, although the contributions to regressions were statistically insignificant. For the biomass conversion function on one variable, the conversion factor decreased with increasing diameter, but for the conversion function on two variables, the conversion factor increased with increasing diameter but decreased with in- creasing tree height.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.30671476 and 30271067).
文摘Cold acclimation is associated with many metabolic changes that lead to an increase of freezing tolerance. In order to investigate the biochemical process of cold acclimation in Ammopiptanthus mongolicus, seedlings were acclimated at 2℃ under 16-h photoperiod （150 μmol·m^-2·s^-1 photosynthetically active radiation） for 14 d. Freezing tolerance in seedlings increased after 14 d of cold-hardening. Contents of protein, proline and solute carbohydrate in cotyledon increased after cold acclimation. Patterns of isozymes of superoxide dismutase （SOD）, peroxidase, catalase and polyphenol oxidase （PPO） were investigated. The activities of SOD, peroxidase and PPO in cold acclimated plants were increased during cold-hardening. We deduced that compatible solutes and antioxidant enzymes play important roles in development of freezing tolerance during cold acclimation in this evergreen woody plant.
基金supported by the National Natural Science Foundation of China (51773134)the Sichuan Science and Technology Program (2019YFH0112)+2 种基金the Fundamental Research Funds for the Central UniversitiesInstitutional Research Fund from Sichuan University (2021SCUNL201)the 111 Project (B20001)。
文摘The rapid development and widespread application of lithium-ion batteries(LIBs) have increased demand for high-safety and high-performance LIBs. Accordingly, various additives have been used in commercial liquid electrolytes to severally adjust the solvation structure of lithium ions, control the components of solid electrolyte interphase, or reduce flammability. While it is highly desirable to develop low-cost multifunctional electrolyte additives integrally that address both safety and performance on LIBs, significant challenges remain. Herein, a novel phosphorus-containing organic small molecule, bis(2-methoxyethyl) methylphosphonate(BMOP), was rationally designed to serve as a fluorine-free and multifunctional additive in commercial electrolytes. This novel electrolyte additive is low-toxicity,high-efficiency, low-cost, and electrode-compatible, which shows the significant improvement to both electrochemical performance and fire safety for LIBs through regulating the electrolyte solvation structure, constructing the stable electrode-electrolyte interphase, and suppressing the electrolyte combustion. This work provides a new avenue for developing safer and high-performance LIBs.
基金supported by the National Natural Science Foundation of China(Grant No.51572238,51725102)the Zhejiang Provincial Natural Science Foundation of China(Grant No.LY19E020013)Hunan Provincial Science and Technology Major Project of China(Grant Nos.2020GK1014,2021GK2018)。
文摘Solid-state lithium metal batteries are promising next-generation batteries for both micro-scale integrated electronic devices and macro-scale electric vehicles.However,electrochemical incompatibility between electrolyte and electrodes causes continuous performance degradation.Here,we report a unique design of a double-layer composite solid-state electrolyte(D-CSE),where each layer,composed of both polymer and ceramics,is electrochemically compatible with its contacting electrode(Li anode or LiCoO_(2)cathode).The D-CSE has a small thickness(50μm),high thermal stability(up to 160℃ without noticeable deformation),and good flexibility even at a high ceramics content(66.7 wt%).Large-area selfstanding film can be obtained by a facile coating route.The electrolyte/electrode interface can be further enhanced via forming a soft interface by in-situ polymerization.Quasi-solid-state Li|D-CSE|LiCoO_(2)coin cells with the cathode-supported D-CSE can deliver a high initial discharge capacity of 134 mAh g^(-1) and a high capacity retention of 83%after 200 cycles at 0.5 C and 60℃.Quasi-solid-state Li|D-CSE|LiCoO_(2)pouch cells(designed capacity 8.6 mAh)with the self-standing D-CSE have a high retention of80%after 180 cycles at 2 mA charge and 4 mA discharge.At a high cathode loading(19.1 mg cm^(-2)),the Li|D-CSE|LiCoO_(2)pouch cell still can be stably cycled,and can withstand abuse tests of folding,cutting and nail penetration,indicating practical applications of the D-CSE.
基金supported by National Natural Science Foundation of China(U2066211,52177124,52107134)the Institute of Electrical Engineering,CAS(E155610101)+1 种基金the DNL Cooperation Fund,CAS(DNL202023)the Youth Innovation Promotion Association of CAS(2019143).
文摘Peer-to-peer(P2P)energy trading refers to a type of decentralized transaction,where the energy from distributed energy resources is directly traded between peers.A key challenge in peer-to-peer energy trading is designing a safe,efficient,and transparent trading model and operating mechanism.In this study,we consider a P2P trading environment based on blockchain technology,where prosumers can submit bids or offers without knowing the reports of others.We propose an Arrow-d’Aspremont-Gerard-Varet(AGV)-based mechanism to encourage prosumers to submit their real reserve price and determine the P2P transaction price.We demonstrate that the AGV mechanism can achieve Bayesian incentive compatibility and budget balance.Kernel density estimation(KDE)is used to derive the prior distribution from the historical bid/offer information of the agents.Case studies are carried out to analyze and evaluate the proposed mechanism.Simulation results verify the effectiveness of the proposed mechanism in guiding agents to report the true reserve price while maximizing social welfare.Moreover,we discuss the advantages of budget balance for decentralized trading by comparing the Vickrey-Clarke-Groves(VCG)and AGV mechanisms.
基金Project supported by the National Natural Science Foundation of China (Grant No.51202291)
文摘A thin radar-infrared stealth-compatible structure with reflectivity below -10 dB in the whole radar X wave band and infrared emissivity less than 0.3 in the infrared region of 8μm-14 μm is reported. The designed stealth-compatible structure consists of metallic frequency selective surface （MFSS）, resistive frequency selective surface （RFSS）, and metal backing from the top down, and it is only 2. l-mm thick. The MFSS is made up of some divided low infrared emissivity metal copper films, and the RFSS consists of a capacitive array of square resistive patches. They are placed close together, working as an admittance sheet because of a mutual influence between them, and the equivalent admittance sheet greatly reduces the thickness of the whole structure. The proposed stealth-compatible structure is verified both by simulations and by experimental results. These results indicate that our proposed stealth-compatible structure has potential applications in stealth fields.
基金supported by the National Natural Science Foundation of China(NSFC)under Grant No.61971452 and Grant No.91538203supported by the Fundamental Research Funds for the Central Universities Grant SCUEC-CZY19038
文摘Rate Compatible Modulation(RCM)is an efficient technique for high spectral efficiency seamless transmission over highly dynamic wireless channels.However,its high decoding complexity at the receiver prevents it from being applied in scenarios where computation resources are limited.To alleviate this problem,an RCM with variable weight sets(RCM-VWS)was presented in the literature to significantly reduce its complexity by employing weight sets of different complexities for channels at different signal-tonoise-ratio(SNR).However,RCM-VWS has to introduce an undesired feedback channel for the transmission of SNR information that is estimated at the receiver and transmitted back to the transmitter for weight set selection.To achieve a low computational complexity while avoiding feedback transmission at the same time,a novel RCM scheme with hybrid weight set(RCM-HWS)is introduced in this paper.A low complexity of decoding is allowed by gradually reducing the complexity of weight sets based on the number symbols already sent.It also avoids the feedback of SNRs since we can deduce SNRs from the number of the symbols transmitted and use a hybrid weight set we have designed.The theoretical analysisand simulation results show that the proposed scheme has the advantages of low demodulation complexity and not requiring feedback channel while maintaining the same transmission throughput as that of the conventional RCM.Therefore,the proposed scheme has a wider range of applications,especially in the case that feedback channel is not available.
基金the Science&Technology Innovation Fund of AVIC Manufacturing Technology Institute,China(Grant No.KS91007113)。
文摘A radar-infrared compatible stealth surface is designed and analyzed.Without modifying the radar absorbing material(RAM),the design can theoretically achieve radar-infrared compatibility and broadband radar absorption through surface patterns and structures.A transmission-line-based model(TLM)is developed to analyze the radar absorbing performance of the surface.Optimization of the structure geometries is conducted aiming to maximize the-10 d B absorption bandwidth in 2–18 GHz.Surface with optimized structure geometries exhibits a superior absorption bandwidth,more than twice the bandwidth of the original 1.5 mm RAM slab,while maintaining a relatively low infrared emissivity.
基金The project is supported by Naural Science Foundation Committee of China
文摘We have developed two 474 THz(633 nm)new iodine stabilized He-Ne lasers with compatible system of third and fifth harmonic locking.The frequency stability is 1.0×10-11/ 1s and 3.5×10-12 / 10s with third harmonic locking,and corresponding values are 1.3×10-11/1s and 4.0×10-12/ 10s with fifth harmonic locking.We found that the frequency difference between the same component with third and fifth harmonic locking are from 5 kHz to SO kHz.Our experiment and analysis indicate that the center of fifth harmonic signals is closer to the Lorentzian center in iodine absorption component than one of the third harmonic signals,and the reproducibility with fifth harmonic locking is also better than one with third harmonic locking.
基金Supported by the National High Technology Research and Development Program of China under Grant No 2015AA042602
文摘We present a micro-Pirani vacuum gauge using the low-resistivity monocrystal silicon as the heaters and heat sinks fabricated by the post complementary metal oxide semiconductor （CMOS） microelectromechanical system （MEMS） process. The metal interconnection of the device is fabricated by a 0.5 μm standard CMOS process on 8-inch silicon wafer. Then, a SiO2-Si low-temperature fusion bonding is developed to bond the CMOS wafer and the MEMS wafer, with the electrical connection realized by the tungsten through silicon via process. Wafer- level A1Ge euteetic bonding is adopted to package the Pirani gauge in a non-hermetic cavity to protect the gauge from being damaged or contaminated in the dicing and assembling process, and to make it suitable for actual applications. To increase the accuracy of the test and restrain negative influence of temperature drift, the Wheatstone bridge structure is introduced. The test results show that before capping, the gauge has an average sensitivity of 1.04 × 104 K.W-1Torr-1 in dynamic range of 0.01 20 Torr. After capping, the sensitivity of the gauge does not decrease but increases to 1.12 × 104 K.W-1 Torr-1.
基金supported by the National Natural Science Foundation of China(No.61401164,No.61201145,No.61471175)the Natural Science Foundation of Guangdong Province of China(No.2014A030310308)the Supporting Plan for New Century Excellent Talents of the Ministry of Education(No.NCET-13-0805)
文摘In this paper, we propose a new method to derive a family of regular rate-compatible low-density parity-check（RC-LDPC） convolutional codes from RC-LDPC block codes. In the RC-LDPC convolutional family, each extended sub-matrix of each extended code is obtained by choosing specified elements from two fixed matrices HE1K and HE1K, which are derived by modifying the extended matrices HE1 and HE2 of a systematic RC-LDPC block code. The proposed method which is based on graph extension simplifies the design, and prevent the defects caused by the puncturing method. It can be used to generate both regular and irregular RC-LDPC convolutional codes. All resulted codes in the family are systematic which simplify the encoder structure and have maximum encoding memories which ensure the property. Simulation results show the family collectively offer a steady improvement in performance with code compatibility over binary-input additive white Gaussian noise channel（BI-AWGNC）.
