InSe has emerged as a promising candidate for next-generation electronics due to its predicted ultrahigh electrical performance.However,the efficacy of the InSe transistor in meeting application requirements is hinder...InSe has emerged as a promising candidate for next-generation electronics due to its predicted ultrahigh electrical performance.However,the efficacy of the InSe transistor in meeting application requirements is hindered due to its sensitivity to interfaces.In this study,we have achieved notable enhancement in the electrical performance of InSe transistors through interface engineering.We engineered an InSe/h-BN heterostructure,effectively suppressing dielectric layer-induced scattering.Additionally,we successfully established excellent metal-semiconductor contacts using graphene ribbons as a buffer layer.Through a methodical approach to interface engineering,our graphene/InSe/h-BN transistor demonstrates impressive on-state current,field-effect mobility,and on/off ratio at room temperature,reaching values as high as 1.1 mA/μm,904 cm^(2)·V^(-1)·s^(-1),and>10~6,respectively.Theoretical computations corroborate that the graphene/InSe heterostructure shows significant interlayer charge transfer and weak interlayer interaction,contributing to the enhanced performance of InSe transistors.This research offers a comprehensive strategy to elevate the electrical performance of InSe transistors,paving the way for their utilization in future electronic applications.展开更多
During high-speed flight,both thermal and mechani-cal loads can degrade the electrical performance of the antenna-radome system,which can subsequently affect the performance of the guidance system.This paper presents ...During high-speed flight,both thermal and mechani-cal loads can degrade the electrical performance of the antenna-radome system,which can subsequently affect the performance of the guidance system.This paper presents a method for evalu-ating the electrical performance of the radome when subjected to thermo-mechanical-electrical(TME)coupling.The method involves establishing a TME coupling model(TME-CM)based on the TME sharing mesh model(TME-SMM)generated by the tetrahedral mesh partitioning of the radome structure.The effects of dielectric temperature drift and structural deformation on the radome’s electrical performance are also considered.Firstly,the temperature field of the radome is obtained by tran-sient thermal analysis while the deformation field of the radome is obtained by static analysis.Subsequently,the dielectric varia-tion and structural deformation of the radome are accurately incorporated into the electrical simulation model based on the TME-SMM.The three-dimensional(3D)ray tracing method with the aperture integration technique is used to calculate the radome’s electrical performance.A representative example is provided to illustrate the superiority and necessity of the pro-posed method.This is achieved by calculating and analyzing the changes in the radome’s electrical performance over time dur-ing high-speed flight.展开更多
The change of electrical performances of silicon-germanium (SiGe)heterojunction bipolar transistor (HBT) and Si bipolar junction transistor (BJT) was studied as afunction of reactor fast neutron radiation fluence. Alt...The change of electrical performances of silicon-germanium (SiGe)heterojunction bipolar transistor (HBT) and Si bipolar junction transistor (BJT) was studied as afunction of reactor fast neutron radiation fluence. Alter neutron irradiation, the collector currentI_c and the current gain beta decrease, and the base current I_b increases generally for SiGe HBT.The higher the neutron irradiation fluence is, the larger I_b increases. For conventional Si BJT,I_c and I_b increase as well as beta decreases much larger than SiGe HBT at the same fluence. It isshown that SiGe HBT has a larger anti-radiation threshold and better anti-radiation performance thanSi BJT. The mechanism of performance changes induced by irradiation was preliminarily discussed.展开更多
Aiming at the problem of the surface accuracy and electrical performance of the antenna in space environment are reduced due to thermal deformation caused by temperature load. This paper presents a method to compensat...Aiming at the problem of the surface accuracy and electrical performance of the antenna in space environment are reduced due to thermal deformation caused by temperature load. This paper presents a method to compensate the thermally induced shape distortion of antenna reflector by actively adjusting actuators in order to improve the electrical performance. The adjustment of each actuator is related to the local deformation of the panel. Then, taking a space deployable antenna with a diameter of 5 meters as an example, the finite element model is established. According to the range of the temperature variation in space (<span style="white-space:nowrap;">−</span>180<span style="white-space:nowrap;">°</span>C - 200<span style="white-space:nowrap;">°</span>C), different temperature loads are applied to the antenna. The variation of electrical properties and surface accuracy is analyzed and the worst working condition is determined, and the antenna is compensated based on this condition. Then, four different electrical performance parameters are used as the optimization objectives, and the electromechanical coupling optimization model is established, and the PSO algorithm is used to optimize the actuators adjustments. The results show that the method can effectively improve the electrical performance of the deformed reflector antenna.展开更多
The change of electrical performances of 1 MeV electron irradiated silicon-germanium (SiGe) heterojunction bipolar transistor (HBT) and Si bipolar junction transistor (BJT) was studied. After electron irradiation, bot...The change of electrical performances of 1 MeV electron irradiated silicon-germanium (SiGe) heterojunction bipolar transistor (HBT) and Si bipolar junction transistor (BJT) was studied. After electron irradiation, both the collector current IC and the base current IB changed a little, and the current gain β decreased a little for SiGe HBT. The higher the electron irradiation fluence was, the lower the IC decreased. For conventional Si BJT, IC and IB increased as well as /? decreased much larger than SiGe HBT under the same fluence. The contribution of IB was more important to the degradation of β for both SiGe HBT and Si BJT. It was shown that SiGe HBT had a larger anti-radiation threshold and better anti-radiation performance than Si BJT. The mechanism of electrical performance changes induced by irradiation was preliminarily discussed.展开更多
Fueled by the increasing imperative for sustainable energy solutions and the burgeoning emphasis on health awareness,self-powered techniques have undergone notable strides in advancement.Triboelectric nanogenerators(T...Fueled by the increasing imperative for sustainable energy solutions and the burgeoning emphasis on health awareness,self-powered techniques have undergone notable strides in advancement.Triboelectric nanogenerators(TENGs)stand out as a prominent device capitalizing on the principles of triboelectrification and electrostatic induction to generate electricity or electrical signals.In efforts to augment the electrical output performance of TENGs and broaden their range of applications,researchers have endeavored to refine materials,surface morphology,and structural design.Among them,physical morphological modifications play a pivotal role in enhancing the electrical properties of TENGs by increasing the contact surface area,which can be achieved by building micro-/nano-structures on the surface or inside the friction material.In this review,we summarize the common morphologies of TENGs,categorize the morphologies into surface and internal structures,and elucidate their roles in enhancing the electric output performance of devices.Moreover,we systematically classify the methodologies employed for morphological preparation into physical and chemical approaches,thereby furnishing a comprehensive survey of the diverse techniques.Subsequently,typical applications of TENGs with special morphology divided by energy harvesting and self-powered sensors are presented.Finally,an overview of the challenges and future trajectories pertinent to TENGs is conducted.Through this endeavor,the aim of this article is to catalyze the evolution of further strategies for enhancing performance of TENGs.展开更多
Triboelectric nanogenerators(TENGs)offer a selfsustaining power solution for marine regions abundant in resources but constrained by energy availability.Since their pioneering use in wave energy harvesting in 2014,nea...Triboelectric nanogenerators(TENGs)offer a selfsustaining power solution for marine regions abundant in resources but constrained by energy availability.Since their pioneering use in wave energy harvesting in 2014,nearly a decade of advancements has yielded nearly thousands of research articles in this domain.Researchers have developed various TENG device structures with diverse functionalities to facilitate their commercial deployment.Nonetheless,there is a gap in comprehensive summaries and performance evaluations of TENG structural designs.This paper delineates six innovative structural designs,focusing on enhancing internal device output and adapting to external environments:high space utilization,hybrid generator,mechanical gain,broadband response,multi-directional operation,and hybrid energy-harvesting systems.We summarize the prevailing trends in device structure design identified by the research community.Furthermore,we conduct a meticulous comparison of the electrical performance of these devices under motorized,simulated wave,and real marine conditions,while also assessing their sustainability in terms of device durability and mechanical robustness.In conclusion,the paper outlines future research avenues and discusses the obstacles encountered in the TENG field.This review aims to offer valuable perspectives for ongoing research and to advance the progress and application of TENG technology.展开更多
Because of the different ways in which contact materials work, the basic requirements for silver metal oxide contact materials are different. They are anti-welded and anti-erosion when closed, anti-erosion when broken...Because of the different ways in which contact materials work, the basic requirements for silver metal oxide contact materials are different. They are anti-welded and anti-erosion when closed, anti-erosion when broken, and arc easily moved and have smaller contact resistance. In this paper, La2O3 is used as a stable oxide in contact material to replace CdO. A new type of Ag/SnO2-La2O3-Bi2O3 contact material is first obtained through using powder metallurgical method. Then electrical contact material parameter tester is used to test the electrical contact performance of the contact material. Through experiments, the arcing voltage and current curves, arcing energy curves, fusion power curves while broken and contact resistance while closed were obtained. Analysis of the results showed that the addition of La2O3 makes the contact material have the following advantages: smaller electrical wear, smaller arc energy, smaller contact resistance and arc is more easily extinguished.展开更多
A generalized mathematical model of human body current threshold for perception was established and the current flowing through human body could be arbitrary cyclical waveforms.The relationship between human body curr...A generalized mathematical model of human body current threshold for perception was established and the current flowing through human body could be arbitrary cyclical waveforms.The relationship between human body current threshold for perception and current frequency, true root mean square(RMS) value and influence factor was described.A test system was established based on electroencephalogram(EEG) to study the relationship between human body current threshold for perception and current waveform, frequency ...展开更多
In this work,poly(3-hexylthiophene)(P3HT)ultrathin films(P3HT-T)were prepared by spin-coating a dilute P3HT solution(in a toluene:o-dichlorobenzene(Tol:ODCB)blend with a volume ratio of 80:20)with ultrasonication and ...In this work,poly(3-hexylthiophene)(P3HT)ultrathin films(P3HT-T)were prepared by spin-coating a dilute P3HT solution(in a toluene:o-dichlorobenzene(Tol:ODCB)blend with a volume ratio of 80:20)with ultrasonication and the addition of the nucleating agent bicycle[2.2.1]heptane-2,3-dicarboxylic acid disodium salt(HPN-68L)on glass,Si wafers and indium tin oxide(ITO)substrates.The electrical and mechanical properties of the P3HT-T ultrathin films were investigated,and it was found that the conductivity and crack onset strain(COS)were simultaneously improved in comparison with those of the corresponding pristine P3HT film(P3HT-0,without ultrasonication and nucleating agent)on the same substrate,regardless of what substrate was used.Moreover,the conductivity of P3HT-T ultrathin films on different substrates was similar(varying from 3.7 S·cm^(-1)to 4.4 S·cm^(-1)),yet the COS increased from 97%to 138%by varying the substrate from a Si wafer to ITO.Combining grazing-incidence wide-angle X-ray diffraction(GIXRD),UV-visible(UV-Vis)spectroscopy and atomic force microscopy(AFM),we found that the solid order and crystallinity of the P3HT-T ultrathin film on the Si wafer are highest,followed by those on glass,and much lower on ITO.Finally,the surface energy and roughness of three substrates were investigated,and it was found that the polar component of the surface energyγp plays a critical role in determining the crystalline microstructures of P3HT ultrathin films on different substrates.Our work indicates that the P3HT ultrathin film can obviously improve the stretchability and simultaneously retain similar electrical performance when a suitable substrate is chosen.These findings offer a new direction for research on stretchable CP ultrathin films to facilitate future practical applications.展开更多
The corrosion behavior and life of Sn−3.0Ag−0.5Cu solder joints were investigated through fire smoke exposure experiments within the temperature range of 45−80℃.The nonlinear Wiener process and Arrhenius equation wer...The corrosion behavior and life of Sn−3.0Ag−0.5Cu solder joints were investigated through fire smoke exposure experiments within the temperature range of 45−80℃.The nonlinear Wiener process and Arrhenius equation were used to establish the probability distribution function and prediction model of the solder joint’s average life and individual remaining useful life.The results indicate that solder joint resistance shows a nonlinear growth trend with time increasing.After 24 h,the solder joint transforms from spherical to rose-like shapes.Higher temperatures accelerate solder joint failure,and the relationship between failure time and temperature conforms to the Arrhenius equation.The predicted life of the model is in good agreement with experimental results,demonstrating the effectiveness and accuracy of the model.展开更多
The design and fabrication of high toughness electromagnetic interference(EMI)shielding composite films with diminished reflection are an imperative task to solve electromagnetic pollution problem.Ternary MXene/ANF(ar...The design and fabrication of high toughness electromagnetic interference(EMI)shielding composite films with diminished reflection are an imperative task to solve electromagnetic pollution problem.Ternary MXene/ANF(aramid nanofibers)–MoS_(2)composite films with nacre-like layered structure here are fabricated after the introduction of MoS_(2)into binary MXene/ANF composite system.The introduction of MoS_(2)fulfills an impressive“kill three birds with one stone”improvement effect:lubrication toughening mechanical performance,reduction in secondary reflection pollution of electromagnetic wave,and improvement in the performance of photothermal conversion.After the introduction of MoS_(2)into binary MXene/ANF(mass ratio of 50:50),the strain to failure and tensile strength increase from 22.1±1.7%and 105.7±6.4 MPa and to 25.8±0.7%and 167.3±9.1 MPa,respectively.The toughness elevates from 13.0±4.1 to 26.3±0.8 MJ m^(−3)(~102.3%)simultaneously.And the reflection shielding effectiveness(SE_(R))of MXene/ANF(mass ratio of 50:50)decreases~10.8%.EMI shielding effectiveness(EMI SE)elevates to 41.0 dB(8.2–12.4 GHz);After the introduction of MoS_(2)into binary MXene/ANF(mass ratio of 60:40),the strain to failure increases from 18.3±1.9%to 28.1±0.7%(~53.5%),the SE_(R)decreases~22.2%,and the corresponding EMI SE is 43.9 dB.The MoS_(2)also leads to a more efficient photothermal conversion performance(~45 to~55℃).Additionally,MXene/ANF–MoS_(2)composite films exhibit excellent electric heating performance,quick temperature elevation(15 s),excellent cycle stability(2,2.5,and 3 V),and long-term stability(2520 s).Combining with excellent mechanical performance with high MXene content,electric heating performance,and photothermal conversion performance,EMI shielding ternary MXene/ANF–MoS_(2)composite films could be applied in many industrial areas.This work broadens how to achieve a balance between mechanical properties and versatility of composites in the case of high-function fillers.展开更多
It was prepared by glycine-nitrate process (GNP) method for a novel composite material La0.7Sr0.3Cr0.5Mn0.5O3-δ-Ce0.8Ca0.2O2-δ (LSCM-CDC) used for anode of intermediate temperature solid oxide fuel cell (ITSOFC). Th...It was prepared by glycine-nitrate process (GNP) method for a novel composite material La0.7Sr0.3Cr0.5Mn0.5O3-δ-Ce0.8Ca0.2O2-δ (LSCM-CDC) used for anode of intermediate temperature solid oxide fuel cell (ITSOFC). The microstructure and properties of composite anode LSCM-CDC were measured via X-ray diffraction (XRD), scanning electron microscopy (SEM), AC impedance and four-probe direct current methods. Fluorite-perovskite compounded phase structure was obtained after being sintered at 1400 ℃ for 15 h, the optimum composition of the composite anode of LSCM and CDC was 7 to 3 at molar ratio. At 850 ℃, the electronic conductivity was 6.49 S·cm-1 in air and 1 S·cm-1 in the reduction atmosphere, respectively. The AC impedance spectra with two arcs showed that LSCM-CDC had low ionic conductivity, which was about two orders of magnitude lower than the electronic conductivity. LSCM-CDC composite anode was stable under different temperatures in pure methane gas with good catalytic performance, which indicated that the composite was a promising anode for ITSOFC.展开更多
A novel grain boundary(GB) model characterized with different angles and positions in the nanowire was set up.By means of device simulator,the effects of grain boundary angle and location on the electrical performance...A novel grain boundary(GB) model characterized with different angles and positions in the nanowire was set up.By means of device simulator,the effects of grain boundary angle and location on the electrical performance of ZnO nanowire FET(Nanowire Field-Effect Transistor) with a wrap-around gate configuration,were explored.With the increase of the grain boundary angle,the electrical performance degrades gradually.When a grain boundary with a smaller angle,such as 5° GB,is located close to the source or drain electrode,the grain boundary is partially depleted by an electric field peak,which leads to the decrease of electron concentration and the degradation of transistor characteristics.When the 90° GB is located at the center of the nanowire,the action of the electric field is balanced out,so the electrical performance of transistor is better than that of the 90° GB located at the other positions.展开更多
For a distributed drive electric vehicle（DDEV） driven by four in-wheel motors, advanced vehicle dynamic control methods can be realized easily because motors can be controlled independently, quickly and precisely. A...For a distributed drive electric vehicle（DDEV） driven by four in-wheel motors, advanced vehicle dynamic control methods can be realized easily because motors can be controlled independently, quickly and precisely. And direct yaw-moment control（DYC） has been widely studied and applied to vehicle stability control. Good vehicle handling performance： quick yaw rate transient response, small overshoot, high steady yaw rate gain, etc, is required by drivers under normal conditions, which is less concerned, however. Based on the hierarchical control methodology, a novel control system using direct yaw moment control for improving handling performance of a distributed drive electric vehicle especially under normal driving conditions has been proposed. The upper-loop control system consists of two parts： a state feedback controller, which aims to realize the ideal transient response of yaw rate, with a vehicle sideslip angle observer; and a steering wheel angle feedforward controller designed to achieve a desired yaw rate steady gain. Under the restriction of the effect of poles and zeros in the closed-loop transfer function on the system response and the capacity of in-wheel motors, the integrated time and absolute error（ITAE） function is utilized as the cost function in the optimal control to calculate the ideal eigen frequency and damper coefficient of the system and obtain optimal feedback matrix and feedforward matrix. Simulations and experiments with a DDEV under multiple maneuvers are carried out and show the effectiveness of the proposed method： yaw rate rising time is reduced, steady yaw rate gain is increased, vehicle steering characteristic is close to neutral steer and drivers burdens are also reduced. The control system improves vehicle handling performance under normal conditions in both transient and steady response. State feedback control instead of model following control is introduced in the control system so that the sense of control intervention to drivers is relieved.展开更多
Continuous CNT fibers have been directly fabricated in a speed of 50 m/h-400 m/h,based on an improved chemical vapor deposition method.As-prepared fibers are further post-treated by acid.According to the SEM images an...Continuous CNT fibers have been directly fabricated in a speed of 50 m/h-400 m/h,based on an improved chemical vapor deposition method.As-prepared fibers are further post-treated by acid.According to the SEM images and Raman spectra,the acid treatment results in the compaction and surface modification of the CNTs in fibers,which are beneficial for the electron and load transfer.Compared to the HNO3 treatment,HClSO_3 or H_2SO_4 treatment is more effective for the improvement of the fibers＇ properties.After HCISO_3 treatment for 2 h,the fibers＇ strength and electrical conductivity reach up to-2 GPa and-4.3 MS/m,which are promoted by-200%and almost one order of magnitude than those without acid treatment,respectively.The load-bearing status of the CNT fibers are analyzed based on the downshifts of the G＇ band and the strain transfer factor of the fibers under tension.The results reveal that acid treatment could greatly enhance the load transfer and inter-bundle strength.With the HCISO3 treatment,the strain transfer factor is enhanced from-3.9%to-53.6%.展开更多
Self-destructing chips have promising applications for securing data.This paper proposes a new concept of energetic diodes for the first time,which can be used for self-destructive chips.A simple two-step electrochemi...Self-destructing chips have promising applications for securing data.This paper proposes a new concept of energetic diodes for the first time,which can be used for self-destructive chips.A simple two-step electrochemical deposition method is used to prepare ZnO/CuO/Al energetic diode,in which N-type ZnO and P-type CuO are constricted to a PN junction.This paper comprehensively discusses the material properties,morphology,semiconductor characteristics,and exploding performances of the energetic diode.Experimental results show that the energetic diode has typical rectification with a turn-on voltage of about 1.78 V and a reverse leakage current of about 3×10^(-4)A.When a constant voltage of 70 V loads to the energetic diode in the forward direction for about 0.14 s or 55 V loads in the reverse direction for about 0.17 s,the loaded power can excite the energetic diode exploding and the current rises to about100 A.Due to the unique performance of the energetic diode,it has a double function of rectification and explosion.The energetic diode can be used as a logic element in the normal chip to complete the regular operation,and it can release energy to destroy the chip accurately.展开更多
Electroactive shape memory composites were synthesized using polybutadiene epoxy （PBEP） and bisphenol A type cyanate ester （BACE） filled with different contents of carbon black （CB）. Dynamic mechanical analysis ...Electroactive shape memory composites were synthesized using polybutadiene epoxy （PBEP） and bisphenol A type cyanate ester （BACE） filled with different contents of carbon black （CB）. Dynamic mechanical analysis （DMA）, scanning electron microscopy （SEM）, electrical performance and electroactive shape memory behavior were systematically investigated. It is found that the volume resistivity decreased due to excellent electrical conductivity of CB, in turn resulting in good electroactive shape memory properties. The content of CB and applied voltage had significant influence on electroactive shape memory effect of developed BACE/PBEP/CB composites. Shape recovery can be observed within a few seconds with the CB content of 5 wt% and voltage of 60 V. Shape recovery time decreased with increasing content of CB and voltage. The infrared thermometer revealed that the temperature rises above the glass transition temperature faster with the increase of voltage and the decrease of resistance.展开更多
Strong C-C bonds,nanoscale cross-section and low atomic number make single-walled carbon nanotubes(SWCNTs)a potential candidate material for integrated circuits(ICs)applied in outer space.However,very little work comb...Strong C-C bonds,nanoscale cross-section and low atomic number make single-walled carbon nanotubes(SWCNTs)a potential candidate material for integrated circuits(ICs)applied in outer space.However,very little work combines the simulation calculations with the electrical measurements of SWCNT field-effect transistors(FETs),which limits further understanding on the mechanisms of radiation effects.Here,SWCNT film-based FETs were fabricated to explore the total ionizing dose(TID)and displacement damage effect on the electrical performance under low-energy proton irradiation with different fluences up to 1×1015 p/cm2.Large negative shift of the threshold voltage and obvious decrease of the on-state current verified the TID effect caused in the oxide layer.The stability of the subthreshold swing and the off-state current reveals that the displacement damage caused in the CNT layer is not serious,which proves that the CNT film is radiation-hardened.Specially,according to the simulation,we found the displacement damage caused by protons is different in the source/drain contact area and channel area,leading to varying degrees of change for the contact resistance and sheet resistance.Having analyzed the simulation results and electrical measurements,we explained the low-energy proton irradiation mechanism of the CNT FETs,which is essential for the construction of radiation-hardened CNT film-based ICs for aircrafts.展开更多
基金the support of the National Natural Science Foundation of China (Grant No.62204030)supported in part by the National Natural Science Foundation of China (Grant Nos.62122036,62034004,61921005,61974176,and 12074176)the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No.XDB44000000)。
文摘InSe has emerged as a promising candidate for next-generation electronics due to its predicted ultrahigh electrical performance.However,the efficacy of the InSe transistor in meeting application requirements is hindered due to its sensitivity to interfaces.In this study,we have achieved notable enhancement in the electrical performance of InSe transistors through interface engineering.We engineered an InSe/h-BN heterostructure,effectively suppressing dielectric layer-induced scattering.Additionally,we successfully established excellent metal-semiconductor contacts using graphene ribbons as a buffer layer.Through a methodical approach to interface engineering,our graphene/InSe/h-BN transistor demonstrates impressive on-state current,field-effect mobility,and on/off ratio at room temperature,reaching values as high as 1.1 mA/μm,904 cm^(2)·V^(-1)·s^(-1),and>10~6,respectively.Theoretical computations corroborate that the graphene/InSe heterostructure shows significant interlayer charge transfer and weak interlayer interaction,contributing to the enhanced performance of InSe transistors.This research offers a comprehensive strategy to elevate the electrical performance of InSe transistors,paving the way for their utilization in future electronic applications.
文摘During high-speed flight,both thermal and mechani-cal loads can degrade the electrical performance of the antenna-radome system,which can subsequently affect the performance of the guidance system.This paper presents a method for evalu-ating the electrical performance of the radome when subjected to thermo-mechanical-electrical(TME)coupling.The method involves establishing a TME coupling model(TME-CM)based on the TME sharing mesh model(TME-SMM)generated by the tetrahedral mesh partitioning of the radome structure.The effects of dielectric temperature drift and structural deformation on the radome’s electrical performance are also considered.Firstly,the temperature field of the radome is obtained by tran-sient thermal analysis while the deformation field of the radome is obtained by static analysis.Subsequently,the dielectric varia-tion and structural deformation of the radome are accurately incorporated into the electrical simulation model based on the TME-SMM.The three-dimensional(3D)ray tracing method with the aperture integration technique is used to calculate the radome’s electrical performance.A representative example is provided to illustrate the superiority and necessity of the pro-posed method.This is achieved by calculating and analyzing the changes in the radome’s electrical performance over time dur-ing high-speed flight.
文摘The change of electrical performances of silicon-germanium (SiGe)heterojunction bipolar transistor (HBT) and Si bipolar junction transistor (BJT) was studied as afunction of reactor fast neutron radiation fluence. Alter neutron irradiation, the collector currentI_c and the current gain beta decrease, and the base current I_b increases generally for SiGe HBT.The higher the neutron irradiation fluence is, the larger I_b increases. For conventional Si BJT,I_c and I_b increase as well as beta decreases much larger than SiGe HBT at the same fluence. It isshown that SiGe HBT has a larger anti-radiation threshold and better anti-radiation performance thanSi BJT. The mechanism of performance changes induced by irradiation was preliminarily discussed.
文摘Aiming at the problem of the surface accuracy and electrical performance of the antenna in space environment are reduced due to thermal deformation caused by temperature load. This paper presents a method to compensate the thermally induced shape distortion of antenna reflector by actively adjusting actuators in order to improve the electrical performance. The adjustment of each actuator is related to the local deformation of the panel. Then, taking a space deployable antenna with a diameter of 5 meters as an example, the finite element model is established. According to the range of the temperature variation in space (<span style="white-space:nowrap;">−</span>180<span style="white-space:nowrap;">°</span>C - 200<span style="white-space:nowrap;">°</span>C), different temperature loads are applied to the antenna. The variation of electrical properties and surface accuracy is analyzed and the worst working condition is determined, and the antenna is compensated based on this condition. Then, four different electrical performance parameters are used as the optimization objectives, and the electromechanical coupling optimization model is established, and the PSO algorithm is used to optimize the actuators adjustments. The results show that the method can effectively improve the electrical performance of the deformed reflector antenna.
基金This project is financially supported by the National Natural Science Foundation of China(No.10075029 and 69836020)National“863”Advanced Research Project of China(No.2002AA3Z1230).
文摘The change of electrical performances of 1 MeV electron irradiated silicon-germanium (SiGe) heterojunction bipolar transistor (HBT) and Si bipolar junction transistor (BJT) was studied. After electron irradiation, both the collector current IC and the base current IB changed a little, and the current gain β decreased a little for SiGe HBT. The higher the electron irradiation fluence was, the lower the IC decreased. For conventional Si BJT, IC and IB increased as well as /? decreased much larger than SiGe HBT under the same fluence. The contribution of IB was more important to the degradation of β for both SiGe HBT and Si BJT. It was shown that SiGe HBT had a larger anti-radiation threshold and better anti-radiation performance than Si BJT. The mechanism of electrical performance changes induced by irradiation was preliminarily discussed.
基金financially supported by the Natural Science Foundation of Guangdong Province(No.2024A1515010639)PolyU Postdoc Matching Fund Scheme(No.1-W327),PolyU Grant(No.1-CE0H)+3 种基金Shenzhen Science and Technology Program(No.ZDSYS20220606100406016)Shenzhen Key Laboratory of Photonics and Biophotonics(No.ZDSYS20210623092006020)National Key Laboratory of Green and Long-Life Road Engineering in Extreme Environment(Shenzhen)(No.868-000003010103)National Natural Science Foundation of China(No.52208272)。
文摘Fueled by the increasing imperative for sustainable energy solutions and the burgeoning emphasis on health awareness,self-powered techniques have undergone notable strides in advancement.Triboelectric nanogenerators(TENGs)stand out as a prominent device capitalizing on the principles of triboelectrification and electrostatic induction to generate electricity or electrical signals.In efforts to augment the electrical output performance of TENGs and broaden their range of applications,researchers have endeavored to refine materials,surface morphology,and structural design.Among them,physical morphological modifications play a pivotal role in enhancing the electrical properties of TENGs by increasing the contact surface area,which can be achieved by building micro-/nano-structures on the surface or inside the friction material.In this review,we summarize the common morphologies of TENGs,categorize the morphologies into surface and internal structures,and elucidate their roles in enhancing the electric output performance of devices.Moreover,we systematically classify the methodologies employed for morphological preparation into physical and chemical approaches,thereby furnishing a comprehensive survey of the diverse techniques.Subsequently,typical applications of TENGs with special morphology divided by energy harvesting and self-powered sensors are presented.Finally,an overview of the challenges and future trajectories pertinent to TENGs is conducted.Through this endeavor,the aim of this article is to catalyze the evolution of further strategies for enhancing performance of TENGs.
基金supported by the National Key R&D Project from Ministry of Science and Technology,China(2021YFA1201603)National Natural Science Foundation of China(52073032 and 52192611)the Fundamental Research Funds for the Central Universities.
文摘Triboelectric nanogenerators(TENGs)offer a selfsustaining power solution for marine regions abundant in resources but constrained by energy availability.Since their pioneering use in wave energy harvesting in 2014,nearly a decade of advancements has yielded nearly thousands of research articles in this domain.Researchers have developed various TENG device structures with diverse functionalities to facilitate their commercial deployment.Nonetheless,there is a gap in comprehensive summaries and performance evaluations of TENG structural designs.This paper delineates six innovative structural designs,focusing on enhancing internal device output and adapting to external environments:high space utilization,hybrid generator,mechanical gain,broadband response,multi-directional operation,and hybrid energy-harvesting systems.We summarize the prevailing trends in device structure design identified by the research community.Furthermore,we conduct a meticulous comparison of the electrical performance of these devices under motorized,simulated wave,and real marine conditions,while also assessing their sustainability in terms of device durability and mechanical robustness.In conclusion,the paper outlines future research avenues and discusses the obstacles encountered in the TENG field.This review aims to offer valuable perspectives for ongoing research and to advance the progress and application of TENG technology.
基金Project (No. 502048) supported by the Natural Science Foundation of Hebei Province, China
文摘Because of the different ways in which contact materials work, the basic requirements for silver metal oxide contact materials are different. They are anti-welded and anti-erosion when closed, anti-erosion when broken, and arc easily moved and have smaller contact resistance. In this paper, La2O3 is used as a stable oxide in contact material to replace CdO. A new type of Ag/SnO2-La2O3-Bi2O3 contact material is first obtained through using powder metallurgical method. Then electrical contact material parameter tester is used to test the electrical contact performance of the contact material. Through experiments, the arcing voltage and current curves, arcing energy curves, fusion power curves while broken and contact resistance while closed were obtained. Analysis of the results showed that the addition of La2O3 makes the contact material have the following advantages: smaller electrical wear, smaller arc energy, smaller contact resistance and arc is more easily extinguished.
基金Supported by the Ministry of Science and Technology of China (No. NCSTE-2006-JKZX-167)Beijing Key Laboratory (Measurement and Control of Electro-mechanical Systems) (No. 82063005)
文摘A generalized mathematical model of human body current threshold for perception was established and the current flowing through human body could be arbitrary cyclical waveforms.The relationship between human body current threshold for perception and current frequency, true root mean square(RMS) value and influence factor was described.A test system was established based on electroencephalogram(EEG) to study the relationship between human body current threshold for perception and current waveform, frequency ...
基金supported by the National Natural Science Foundation of China(No.21975029)。
文摘In this work,poly(3-hexylthiophene)(P3HT)ultrathin films(P3HT-T)were prepared by spin-coating a dilute P3HT solution(in a toluene:o-dichlorobenzene(Tol:ODCB)blend with a volume ratio of 80:20)with ultrasonication and the addition of the nucleating agent bicycle[2.2.1]heptane-2,3-dicarboxylic acid disodium salt(HPN-68L)on glass,Si wafers and indium tin oxide(ITO)substrates.The electrical and mechanical properties of the P3HT-T ultrathin films were investigated,and it was found that the conductivity and crack onset strain(COS)were simultaneously improved in comparison with those of the corresponding pristine P3HT film(P3HT-0,without ultrasonication and nucleating agent)on the same substrate,regardless of what substrate was used.Moreover,the conductivity of P3HT-T ultrathin films on different substrates was similar(varying from 3.7 S·cm^(-1)to 4.4 S·cm^(-1)),yet the COS increased from 97%to 138%by varying the substrate from a Si wafer to ITO.Combining grazing-incidence wide-angle X-ray diffraction(GIXRD),UV-visible(UV-Vis)spectroscopy and atomic force microscopy(AFM),we found that the solid order and crystallinity of the P3HT-T ultrathin film on the Si wafer are highest,followed by those on glass,and much lower on ITO.Finally,the surface energy and roughness of three substrates were investigated,and it was found that the polar component of the surface energyγp plays a critical role in determining the crystalline microstructures of P3HT ultrathin films on different substrates.Our work indicates that the P3HT ultrathin film can obviously improve the stretchability and simultaneously retain similar electrical performance when a suitable substrate is chosen.These findings offer a new direction for research on stretchable CP ultrathin films to facilitate future practical applications.
基金National Natural Science Foundation of China (No. 52206180)Fundamental Research Funds for the Central Universities,China (No. WK2320000050)。
文摘The corrosion behavior and life of Sn−3.0Ag−0.5Cu solder joints were investigated through fire smoke exposure experiments within the temperature range of 45−80℃.The nonlinear Wiener process and Arrhenius equation were used to establish the probability distribution function and prediction model of the solder joint’s average life and individual remaining useful life.The results indicate that solder joint resistance shows a nonlinear growth trend with time increasing.After 24 h,the solder joint transforms from spherical to rose-like shapes.Higher temperatures accelerate solder joint failure,and the relationship between failure time and temperature conforms to the Arrhenius equation.The predicted life of the model is in good agreement with experimental results,demonstrating the effectiveness and accuracy of the model.
基金supported by the Talent Fund of Beijing Jiaotong University(No,2023XKRC015)the National Natural Science Foundation of China(Nos.52172081,52073010 and 52373259).
文摘The design and fabrication of high toughness electromagnetic interference(EMI)shielding composite films with diminished reflection are an imperative task to solve electromagnetic pollution problem.Ternary MXene/ANF(aramid nanofibers)–MoS_(2)composite films with nacre-like layered structure here are fabricated after the introduction of MoS_(2)into binary MXene/ANF composite system.The introduction of MoS_(2)fulfills an impressive“kill three birds with one stone”improvement effect:lubrication toughening mechanical performance,reduction in secondary reflection pollution of electromagnetic wave,and improvement in the performance of photothermal conversion.After the introduction of MoS_(2)into binary MXene/ANF(mass ratio of 50:50),the strain to failure and tensile strength increase from 22.1±1.7%and 105.7±6.4 MPa and to 25.8±0.7%and 167.3±9.1 MPa,respectively.The toughness elevates from 13.0±4.1 to 26.3±0.8 MJ m^(−3)(~102.3%)simultaneously.And the reflection shielding effectiveness(SE_(R))of MXene/ANF(mass ratio of 50:50)decreases~10.8%.EMI shielding effectiveness(EMI SE)elevates to 41.0 dB(8.2–12.4 GHz);After the introduction of MoS_(2)into binary MXene/ANF(mass ratio of 60:40),the strain to failure increases from 18.3±1.9%to 28.1±0.7%(~53.5%),the SE_(R)decreases~22.2%,and the corresponding EMI SE is 43.9 dB.The MoS_(2)also leads to a more efficient photothermal conversion performance(~45 to~55℃).Additionally,MXene/ANF–MoS_(2)composite films exhibit excellent electric heating performance,quick temperature elevation(15 s),excellent cycle stability(2,2.5,and 3 V),and long-term stability(2520 s).Combining with excellent mechanical performance with high MXene content,electric heating performance,and photothermal conversion performance,EMI shielding ternary MXene/ANF–MoS_(2)composite films could be applied in many industrial areas.This work broadens how to achieve a balance between mechanical properties and versatility of composites in the case of high-function fillers.
基金the National Natural Science Foundation of China (50204007)the Talent Foundation of Yunnan Prov-ince (2005PY01-33)Program for New Century Excellent Talents in University (NCET-07-0387)
文摘It was prepared by glycine-nitrate process (GNP) method for a novel composite material La0.7Sr0.3Cr0.5Mn0.5O3-δ-Ce0.8Ca0.2O2-δ (LSCM-CDC) used for anode of intermediate temperature solid oxide fuel cell (ITSOFC). The microstructure and properties of composite anode LSCM-CDC were measured via X-ray diffraction (XRD), scanning electron microscopy (SEM), AC impedance and four-probe direct current methods. Fluorite-perovskite compounded phase structure was obtained after being sintered at 1400 ℃ for 15 h, the optimum composition of the composite anode of LSCM and CDC was 7 to 3 at molar ratio. At 850 ℃, the electronic conductivity was 6.49 S·cm-1 in air and 1 S·cm-1 in the reduction atmosphere, respectively. The AC impedance spectra with two arcs showed that LSCM-CDC had low ionic conductivity, which was about two orders of magnitude lower than the electronic conductivity. LSCM-CDC composite anode was stable under different temperatures in pure methane gas with good catalytic performance, which indicated that the composite was a promising anode for ITSOFC.
基金Project(60876022) supported by the National Natural Science Foundation of ChinaProject(50925727) supported by the National Natural Science Funds for Distinguished Young Scholars of China
文摘A novel grain boundary(GB) model characterized with different angles and positions in the nanowire was set up.By means of device simulator,the effects of grain boundary angle and location on the electrical performance of ZnO nanowire FET(Nanowire Field-Effect Transistor) with a wrap-around gate configuration,were explored.With the increase of the grain boundary angle,the electrical performance degrades gradually.When a grain boundary with a smaller angle,such as 5° GB,is located close to the source or drain electrode,the grain boundary is partially depleted by an electric field peak,which leads to the decrease of electron concentration and the degradation of transistor characteristics.When the 90° GB is located at the center of the nanowire,the action of the electric field is balanced out,so the electrical performance of transistor is better than that of the 90° GB located at the other positions.
基金Supported by National Basic Research Program of China(973 Program,Grant No.2011CB711200)National Science and Technology Support Program of China(Grant No.2015BAG17B00)National Natural Science Foundation of China(Grant No.51475333)
文摘For a distributed drive electric vehicle（DDEV） driven by four in-wheel motors, advanced vehicle dynamic control methods can be realized easily because motors can be controlled independently, quickly and precisely. And direct yaw-moment control（DYC） has been widely studied and applied to vehicle stability control. Good vehicle handling performance： quick yaw rate transient response, small overshoot, high steady yaw rate gain, etc, is required by drivers under normal conditions, which is less concerned, however. Based on the hierarchical control methodology, a novel control system using direct yaw moment control for improving handling performance of a distributed drive electric vehicle especially under normal driving conditions has been proposed. The upper-loop control system consists of two parts： a state feedback controller, which aims to realize the ideal transient response of yaw rate, with a vehicle sideslip angle observer; and a steering wheel angle feedforward controller designed to achieve a desired yaw rate steady gain. Under the restriction of the effect of poles and zeros in the closed-loop transfer function on the system response and the capacity of in-wheel motors, the integrated time and absolute error（ITAE） function is utilized as the cost function in the optimal control to calculate the ideal eigen frequency and damper coefficient of the system and obtain optimal feedback matrix and feedforward matrix. Simulations and experiments with a DDEV under multiple maneuvers are carried out and show the effectiveness of the proposed method： yaw rate rising time is reduced, steady yaw rate gain is increased, vehicle steering characteristic is close to neutral steer and drivers burdens are also reduced. The control system improves vehicle handling performance under normal conditions in both transient and steady response. State feedback control instead of model following control is introduced in the control system so that the sense of control intervention to drivers is relieved.
基金Project supported by the National Basic Research Program of China(Grant No.2012CB932302)the National Natural Science Foundation of China(Grant Nos.11634014,51172271,51372269,and 51472264)the“Strategic Priority Research Program”of the Chinese Academy of Sciences(Grant No.XDA09040202)
文摘Continuous CNT fibers have been directly fabricated in a speed of 50 m/h-400 m/h,based on an improved chemical vapor deposition method.As-prepared fibers are further post-treated by acid.According to the SEM images and Raman spectra,the acid treatment results in the compaction and surface modification of the CNTs in fibers,which are beneficial for the electron and load transfer.Compared to the HNO3 treatment,HClSO_3 or H_2SO_4 treatment is more effective for the improvement of the fibers＇ properties.After HCISO_3 treatment for 2 h,the fibers＇ strength and electrical conductivity reach up to-2 GPa and-4.3 MS/m,which are promoted by-200%and almost one order of magnitude than those without acid treatment,respectively.The load-bearing status of the CNT fibers are analyzed based on the downshifts of the G＇ band and the strain transfer factor of the fibers under tension.The results reveal that acid treatment could greatly enhance the load transfer and inter-bundle strength.With the HCISO3 treatment,the strain transfer factor is enhanced from-3.9%to-53.6%.
基金the National Natural Science Foundation of China(Grant Nos.22275092,52372084)the Fundamental Research Funds for the Central Universities(Grant No.30923010920)。
文摘Self-destructing chips have promising applications for securing data.This paper proposes a new concept of energetic diodes for the first time,which can be used for self-destructive chips.A simple two-step electrochemical deposition method is used to prepare ZnO/CuO/Al energetic diode,in which N-type ZnO and P-type CuO are constricted to a PN junction.This paper comprehensively discusses the material properties,morphology,semiconductor characteristics,and exploding performances of the energetic diode.Experimental results show that the energetic diode has typical rectification with a turn-on voltage of about 1.78 V and a reverse leakage current of about 3×10^(-4)A.When a constant voltage of 70 V loads to the energetic diode in the forward direction for about 0.14 s or 55 V loads in the reverse direction for about 0.17 s,the loaded power can excite the energetic diode exploding and the current rises to about100 A.Due to the unique performance of the energetic diode,it has a double function of rectification and explosion.The energetic diode can be used as a logic element in the normal chip to complete the regular operation,and it can release energy to destroy the chip accurately.
文摘Electroactive shape memory composites were synthesized using polybutadiene epoxy （PBEP） and bisphenol A type cyanate ester （BACE） filled with different contents of carbon black （CB）. Dynamic mechanical analysis （DMA）, scanning electron microscopy （SEM）, electrical performance and electroactive shape memory behavior were systematically investigated. It is found that the volume resistivity decreased due to excellent electrical conductivity of CB, in turn resulting in good electroactive shape memory properties. The content of CB and applied voltage had significant influence on electroactive shape memory effect of developed BACE/PBEP/CB composites. Shape recovery can be observed within a few seconds with the CB content of 5 wt% and voltage of 60 V. Shape recovery time decreased with increasing content of CB and voltage. The infrared thermometer revealed that the temperature rises above the glass transition temperature faster with the increase of voltage and the decrease of resistance.
基金This work was financially supported by the National Natural Science Foundation of China(No.61704189)the Common Information System Equipment Pre-Research Special Technology Project(31513020404-2)Youth Innovation Promotion Association of Chinese Academy of Sciences and the Opening Project of Key Laboratory of Microelectronic Devices&Integrated Technology,and the Key Research Program of Frontier Sciences,CAS(Grant ZDBS-LY-JSC015)。
文摘Strong C-C bonds,nanoscale cross-section and low atomic number make single-walled carbon nanotubes(SWCNTs)a potential candidate material for integrated circuits(ICs)applied in outer space.However,very little work combines the simulation calculations with the electrical measurements of SWCNT field-effect transistors(FETs),which limits further understanding on the mechanisms of radiation effects.Here,SWCNT film-based FETs were fabricated to explore the total ionizing dose(TID)and displacement damage effect on the electrical performance under low-energy proton irradiation with different fluences up to 1×1015 p/cm2.Large negative shift of the threshold voltage and obvious decrease of the on-state current verified the TID effect caused in the oxide layer.The stability of the subthreshold swing and the off-state current reveals that the displacement damage caused in the CNT layer is not serious,which proves that the CNT film is radiation-hardened.Specially,according to the simulation,we found the displacement damage caused by protons is different in the source/drain contact area and channel area,leading to varying degrees of change for the contact resistance and sheet resistance.Having analyzed the simulation results and electrical measurements,we explained the low-energy proton irradiation mechanism of the CNT FETs,which is essential for the construction of radiation-hardened CNT film-based ICs for aircrafts.
