Nowadays, a highly integrated valve?controlled cylinder(HIVC) is applied to drive the joints of legged robots. Although the adoption of HIVC has resulted in high?performance robot control, the hydraulic force system s...Nowadays, a highly integrated valve?controlled cylinder(HIVC) is applied to drive the joints of legged robots. Although the adoption of HIVC has resulted in high?performance robot control, the hydraulic force system still has problems, such as strong nonlinearity, and time?varying parameters. This makes HIVC force control very diffcult and complex. How to improve the control performance of the HIVC force control system and find the influence rule of the system parameters on the control performance is very significant. Firstly, the mathematical model of HIVC force control system is established. Then the mathematical expression for parameter sensitivity matrix is obtained by applying matrix sensitivity analysis(PSM). Then, aimed at the sinusoidal response under(three factors and three levels) working conditions, the simulation and the experiment are conducted. While the error between the simulation and experiment can’t be avoided. Therefore, combined with the range analysis, the error in the two performance indexes of sinusoidal response under the whole working condition is analyzed. Besides, the sensitivity variation pattern for each system parameter under the whole working condition is figured out. Then the two sensitivity indexes for the three system parameters, which are supply pressure, proportional gain and initial displacement of piston, are proved experimentally. The proposed method significantly reveals the sensitivity characteristics of HIVC force control system, which can make the contribution to improve the control performance.展开更多
The development of high-sulfur-loading Li-S batteries is a key prerequisite for their commercial applications.This requires to surmount the huge polarization,severe polysulfide shuttling and drastic volume change caus...The development of high-sulfur-loading Li-S batteries is a key prerequisite for their commercial applications.This requires to surmount the huge polarization,severe polysulfide shuttling and drastic volume change caused by electrode thickening.High-strength polar binders are ideal for constructing robust and long-life high-loading sulfur cathodes but show very weak interfacial interaction with non-polar sulfur materials.To address this issue,this work devises a highly integrated sulfur@polydopamine/highstrength binder composite cathodes,targeting long-lasting and high-sulfur-loading Li-S batteries.The super-adhesion polydopamine(PD)can form a uniform nano-coating over the graphene/sulfur(G-S)surface and provide strong affinity to the cross-linked polyacrylamide(c-PAM)binder,thus tightly integrating sulfur with the binder network and greatly boosting the overall mechanical strength/conductivity of the electrode.Moreover,the PD coating and c-PAM binder rich in polar groups can form two effective blockades against the effusion of soluble polysulfides.As such,the 4.5 mg cm−2 sulfur-loaded G-S@PD-c-PAM cathode achieves a capacity of 480 mAh g−1 after 300 cycles at 1 C,while maintaining a capacity of 396 mAh g−1 after 50 cycles at 0.2 C when the sulfur loading rises to 9.1 mg cm−2.This work provides a system-wide concept for constructing high-loading sulfur cathodes through integrated structural design.展开更多
In this paper,high-power LED with many integrated chips is used as thermal resistance analysis research object, and we do thermal resistance testing technology research on it. We put forward the thermocouple point con...In this paper,high-power LED with many integrated chips is used as thermal resistance analysis research object, and we do thermal resistance testing technology research on it. We put forward the thermocouple point contact test method. According to the principle that LED forward voltage changes with temperature,LED heat sink to surface temperature distribution is studied directly in the test,and then we analyze the thermal resistance of high-power LED with many integrated chips when its secondary packaging is introduced. This method makes the measurement of thermal resistance of LED more rapid and convenient. It provides an effective assessment method for the analysis of high power LED device design and engineering application.展开更多
Colorless‐to‐black switching has attracted widespread attention for smart windows and multifunctional displays because they are more useful to control solar energy.However,it still remains a challenge owing to the t...Colorless‐to‐black switching has attracted widespread attention for smart windows and multifunctional displays because they are more useful to control solar energy.However,it still remains a challenge owing to the tremendous difficulties in the design of completely reverse absorptions in transmissive and colored states.Herein,we report on an electrochemical device that can switch between colorless and black by using the electrochemical process of hybrid organic–inorganic perovskite MAPbBr_(3),which shows a high integrated contrast ratio of up to 73%from 400 to 800 nm.The perovskite solution can be used as the active layer to assemble the device,showing superior transmittance over the entire visible region in neutral states.By applying an appropriate voltage,the device undergoes reversible switching between colorless and black,which is attributed to the formation of lead and Br_(2)in the redox reaction induced by the electron transfer process in MAPbBr_(3).In addition,the contrast ratio can be modulated over the entire visible region by changing the concentration and the applied voltage.These results contribute toward gaining an insightful understanding of the electrochemical process of perovskites and greatly promoting the development of switchable devices.展开更多
To make high integrity lightweight metal castings,best practices are required in various stages of casting and heat treatment processes,including liquid metal composition and quality control,casting and gating/riser s...To make high integrity lightweight metal castings,best practices are required in various stages of casting and heat treatment processes,including liquid metal composition and quality control,casting and gating/riser system design,and process optimization.This paper presents best practices for liquid metal processing and quality assurance of molten metal in both melting and mold filling.Best practices for other aspects of lightweight metal casting will be published separately.展开更多
Plowing-extruding tool was designed and plowing-extruding process was investigated.Then,a manufacturing method of integral serrated high-finned tube,plowing-extruding based on variational feed was proposed,in which pl...Plowing-extruding tool was designed and plowing-extruding process was investigated.Then,a manufacturing method of integral serrated high-finned tube,plowing-extruding based on variational feed was proposed,in which plowing-extruding tool moved forward at two different feeds,f1 and f2,in turn.In this method,overlaps that are usually avoided in practical application were utilized to manufacture high fins and average height of fins was up to 1.58 mm.The critical feed(fc) of overlaps forming and terms of high fins forming were analyzed.The main technical parameters that affect the fins height were discussed.The experimental results show that the fins height increases with extruding inclination angle and plowing-extruding depth,and the fins height increases with f1 increasing when f1 is smaller than fc,and decreases with f1 increasing if f1 is larger than fc.展开更多
It is always a bottleneck to design an effective algorithm for linear time-varying systems in engineering applications.For a class of systems,whose coefficients matrix is based on time-varying polynomial,a modified hi...It is always a bottleneck to design an effective algorithm for linear time-varying systems in engineering applications.For a class of systems,whose coefficients matrix is based on time-varying polynomial,a modified highly precise direct integration(VHPD-T method)was presented.Through introducing new variables and expanding dimensions,the system can be transformed into a timeinvariant system,in which the transfer matrix can be computed for once and used forever with a highly precise direct integration method.The method attains higher precision than the common methods(e.g.RK4 and power series)and high efficiency in computation.Some numerical examples demonstrate the validity and efficiency of the method proposed.展开更多
Based on the linear theories of thin cylindrical shells and viscoelastic materials, a governing equation describing vibration of a sandwich circular cylindrical shell with a viscoelastic core under harmonic excitation...Based on the linear theories of thin cylindrical shells and viscoelastic materials, a governing equation describing vibration of a sandwich circular cylindrical shell with a viscoelastic core under harmonic excitation is derived. The equation can be written as a matrix differential equation of the first order, and is obtained by considering the energy dissipation due to the shear deformation of the viscoelastic core layer and the interaction between all layers. A new matrix method for solving the governing equation is then presented With an extended homogeneous capacity precision integration approach. Having obtained these, vibration characteristics and damping effect of the sandwich cylindrical shell can be studied. The method differs from a recently published work as the state vector in the governing equation is composed of displacements and internal forces of the sandwich shell rather than displacements and their derivatives. So the present method can be applied to solve dynamic problems of the kind of sandwich shells with various boundary conditions and partially constrained layer damping. Numerical examples show that the proposed approach is effective and reliable compared with the existing methods.展开更多
This paper presents a high order symplectic con- servative perturbation method for linear time-varying Hamil- tonian system. Firstly, the dynamic equation of Hamilto- nian system is gradually changed into a high order...This paper presents a high order symplectic con- servative perturbation method for linear time-varying Hamil- tonian system. Firstly, the dynamic equation of Hamilto- nian system is gradually changed into a high order pertur- bation equation, which is solved approximately by resolv- ing the Hamiltonian coefficient matrix into a "major compo- nent" and a "high order small quantity" and using perturba- tion transformation technique, then the solution to the orig- inal equation of Hamiltonian system is determined through a series of inverse transform. Because the transfer matrix determined by the method in this paper is the product of a series of exponential matrixes, the transfer matrix is a sym- plectic matrix; furthermore, the exponential matrices can be calculated accurately by the precise time integration method, so the method presented in this paper has fine accuracy, ef- ficiency and stability. The examples show that the proposed method can also give good results even though a large time step is selected, and with the increase of the perturbation or- der, the perturbation solutions tend to exact solutions rapidly.展开更多
Organic optoelectronic integrated devices(OIDs) with ultraviolet(UV) photodetectivity and different color emitting were constructed by using a thermally activated delayed fluorescence(TADF) material 4, 5-bis(ca...Organic optoelectronic integrated devices(OIDs) with ultraviolet(UV) photodetectivity and different color emitting were constructed by using a thermally activated delayed fluorescence(TADF) material 4, 5-bis(carbazol-9-yl)-1, 2-dicyanobenzene(2 CzPN) as host. The OIDs doping with typical red phosphorescent dye [tris(1-phenylisoquinoline)iridium(Ⅲ), Ir(piq)3], orange phosphorescent dye {bis[2-(4-tertbutylphenyl)benzothiazolato-N,C-(2')]iridium(acetylacetonate),(tbt)2 Ir(acac)}, and blue phosphorescent dye [bis(2, 4-di-fluorophenylpyridinato)-tetrakis(1-pyrazolyl)borate iridium(Ⅲ), FIr6] were investigated and compared. The(tbt)2 Ir(acac)-doped orange device showed better performance than those of red and blue devices, which was ascribed to more effective energy transfer. Meanwhile, at a low dopant concentration of 3 wt.%, the(tbt)2 Ir(acac)-doped OIDs showed the maximum luminance, current efficiency, power efficiency of 70786 cd/m^2, 39.55 cd/A, and 23.92 lm/W, respectively, and a decent detectivity of 1.07 × 10^11 Jones at a bias of -2 V under the UV-350 nm illumination. This work may arouse widespread interest in constructing high efficiency and luminance OIDs based on doping phosphorescent dye.展开更多
When kernel density is in the class of continuous function to possessing sufficient derivative of high order(and needn't in the class of corresponding Holder function),in this paper it is given the continuity and...When kernel density is in the class of continuous function to possessing sufficient derivative of high order(and needn't in the class of corresponding Holder function),in this paper it is given the continuity and the differential formulas for singular integrals of high non--integral order. The above results themselves and in order to prove in future the formulas to changing order of integration for singular integrals of high non-integral order(another paper) will have important significance. The method to prove in this paper is more different from the method in the corresponding cass of singular integrals of high integral order.展开更多
Based on the differ—ent theories,TCM andWestern medicine(WM)have their owndifferent understandingsabout the pathogenesisand treatment of highblood pressure(HBP).In TCM the balancesbetween blood-qi,vis—cera—bowel, a...Based on the differ—ent theories,TCM andWestern medicine(WM)have their owndifferent understandingsabout the pathogenesisand treatment of highblood pressure(HBP).In TCM the balancesbetween blood-qi,vis—cera—bowel, and yin—yang are all highly展开更多
Break junctions are important in generating nanosensors and single molecular devices. The mechanically con- trollable break junction is the most widely used method for a break junction due to its simplicity and stabil...Break junctions are important in generating nanosensors and single molecular devices. The mechanically con- trollable break junction is the most widely used method for a break junction due to its simplicity and stability. However, the bandwidths of traditional devices are limited to about a few hertz. Moreover, when using traditional methods it is hard to allow independent control of more than one junction. Here we propose on-chip thermally controllable break junctions to overcome these challenges. This is verified by using finite element analysis. Adopting microelectromechanical systems produces features of high bandwidth and independent controllability to this new break junction system. The proposed method will have a wide range of applications on on-chip high speed independent controllable and highly integrated single molecule devices.展开更多
<div style="text-align:justify;"> Transceiver module and two-dimensional sum difference network are important components of phased array antenna. In this paper, multilayer printed board is used to inte...<div style="text-align:justify;"> Transceiver module and two-dimensional sum difference network are important components of phased array antenna. In this paper, multilayer printed board is used to integrate millimeter wave multi-channel transceiver circuit and sum difference network. The interconnection between them is realized through RF coaxial vertical transition. At the same time, the heat dissipation design and inter channel shielding design of the module are carried out. The RF and low frequency required by the module are completed through the wiring between and within the dielectric plate layers. Finally, 128 arrays are fabricated and verified by multi-channel passive test. The results show that the type transceiver module integrating with two-dimensional sum difference network has good performance, and 128 channels have excellent amplitude and phase characteristics. The integration technology has the characteristics of lightweight, miniaturization, high integration and low manufacturing cost. It can be widely used in miniaturized phased array antennas. </div>展开更多
A high optical magnification three-dimensional imaging system is proposed using an optic microscope whose ocular (eyepiece) is retained and the structure of the transmission mode is not destroyed. The elemental imag...A high optical magnification three-dimensional imaging system is proposed using an optic microscope whose ocular (eyepiece) is retained and the structure of the transmission mode is not destroyed. The elemental image array is captured through the micro lens array. Due to the front diffuse transmission element, each micro lens sees a slightly different spatial perspective of the scene, and a different independent image is formed in each micro lens channel. Each micro lens channel is imaged by a Fourier lens and captured by a CCD. The design translating the stage in x or y provides no parallax. Compared with the conventional integral imaging of micro-objects, the optical magnification of micro-objects in the proposed system can enhanced remarkably. The principle of the enhancement of the image depth is explained in detail and the experimental results are presented.展开更多
The lack of standard to electronic circuits modeling made possible the development of many tools and modeling languages for electronic circuits. In this way, several tools to be used on different descriptions stage of...The lack of standard to electronic circuits modeling made possible the development of many tools and modeling languages for electronic circuits. In this way, several tools to be used on different descriptions stage of the designs are necessary. This paper presents a tool called SF^2HDL (Stateflow to Hardware Description Language or State Transition Table) that translates a finite state machine on state transition diagram representation, described by Stateflow tool, into an input file standard for TABELA program or into a file behavioral VHDL (Very High Speed Integrated Circuits Hardware Description Language) directly. The TABELA program was used to optimization this finite state machine. After that, the TAB2VHDL program was used to generate the VHDL code on register transfer level, what permits comparisons with results obtained by synthesis. The finite state machine must be described by Mealy model and the user can describe the machine on high level abstraction using all Simulink supports. The tool was very efficient on computational cost and it made translation of several cases, for the two VHDL description models. Every state machine translated was simulated and implemented on device EP2C20F484C7 using Quartus II environment.展开更多
To meet the application requirements for a Ka-band space-based TT&C terminal for a launch vehicle,this paper proposes the implementation scheme of a space-based TT&C terminal,analyzes and solves the miniaturiz...To meet the application requirements for a Ka-band space-based TT&C terminal for a launch vehicle,this paper proposes the implementation scheme of a space-based TT&C terminal,analyzes and solves the miniaturized design of equipment and the key technology for high-efficiency heat dissipation.The phased array antenna test shows that without external heat dissipation measures,the phased array antenna can work for a long time to meet the working requirements of launch vehicle,which has been verified in the LM-8 mission,and has wide engineering application prospects.展开更多
The chromosomal position effect can significantly affect the transgene expression,which may provide an efficient strategy for the inauguration of alien genes in new hosts,but has been less explored rationally.The bact...The chromosomal position effect can significantly affect the transgene expression,which may provide an efficient strategy for the inauguration of alien genes in new hosts,but has been less explored rationally.The bacterium Myxococcus xanthus harbors a large circular high-GC genome,and the position effect in this chassis may result in a thousand-fold expression variation of alien natural products.In this study,we conducted transposon insertion at TA sites on the M.xanthus genome,and used enrichment and dilution indexes to respectively appraise high and low expression potentials of alien genes at insertion sites.The enrichment sites are characteristically distributed along the genome,and the dilution sites are overlapped well with the horizontal transfer genes.We experimentally demonstrated the enrichment sites as high expression integration sites(HEISs),and the dilution sites unsuitable for gene integration expression.This work highlights that HEISs are the plug-and-play sites for efficient expression of integrated genes.展开更多
The vigorous development in the field of energy conversion and storage devices directly contributes to the full utilization and convenient use of clean energy.However,some drawbacks of independent energy conversion an...The vigorous development in the field of energy conversion and storage devices directly contributes to the full utilization and convenient use of clean energy.However,some drawbacks of independent energy conversion and storage devices,including unstable,insufficient energy output and dependence on external power supply,are difficult to overcome by self-optimization,thus,hindering their further development and direct application.Coincidentally,the combination of above two devices can solve these problems,which conforms to their intrinsic needs for development.At the same time,the pursuit of portability and miniaturization also promotes the development of the power system toward a highly integrated direction.Therefore,we introduce several integration modes of energy conversion and storage systems,with emphasis on all-in-one power system,possessing the highest integration in this review.From the aspect of device configuration,working mechanisms and their performances,the all-inone power systems based on different energy sources(e.g.,mechanical,solar,thermal,and chemical energy)are discussed and analyzed.Finally,the design strategies are summarized and the potential development directions in the future are proposed.This review aims to provide a comprehensive overview of highly integrated energy conversion and storage system,and seeks to point out the opportunities and orientations of future research in this field.展开更多
基金Supported by National Natural Science Foundation of China(Grant No.51605417)Key Project of Hebei Provincial Natural Science Foundation,China(Grant No.E2016203264)State Key Laboratory of Fluid Power and Mechatronic Systems(Zhejiang University)Open Fund Project(Grant No.GZKF-201502)
文摘Nowadays, a highly integrated valve?controlled cylinder(HIVC) is applied to drive the joints of legged robots. Although the adoption of HIVC has resulted in high?performance robot control, the hydraulic force system still has problems, such as strong nonlinearity, and time?varying parameters. This makes HIVC force control very diffcult and complex. How to improve the control performance of the HIVC force control system and find the influence rule of the system parameters on the control performance is very significant. Firstly, the mathematical model of HIVC force control system is established. Then the mathematical expression for parameter sensitivity matrix is obtained by applying matrix sensitivity analysis(PSM). Then, aimed at the sinusoidal response under(three factors and three levels) working conditions, the simulation and the experiment are conducted. While the error between the simulation and experiment can’t be avoided. Therefore, combined with the range analysis, the error in the two performance indexes of sinusoidal response under the whole working condition is analyzed. Besides, the sensitivity variation pattern for each system parameter under the whole working condition is figured out. Then the two sensitivity indexes for the three system parameters, which are supply pressure, proportional gain and initial displacement of piston, are proved experimentally. The proposed method significantly reveals the sensitivity characteristics of HIVC force control system, which can make the contribution to improve the control performance.
基金supported by the National Natural Science Foundation of China(21875155,51675275,21703185 and 21473119)Q.B.Z.acknowledges the Leading Project Foundation of Science Department of Fujian Province(2018H0034)Shenzhen Science and Technology Planning Project(JCYJ20170818153427106).
文摘The development of high-sulfur-loading Li-S batteries is a key prerequisite for their commercial applications.This requires to surmount the huge polarization,severe polysulfide shuttling and drastic volume change caused by electrode thickening.High-strength polar binders are ideal for constructing robust and long-life high-loading sulfur cathodes but show very weak interfacial interaction with non-polar sulfur materials.To address this issue,this work devises a highly integrated sulfur@polydopamine/highstrength binder composite cathodes,targeting long-lasting and high-sulfur-loading Li-S batteries.The super-adhesion polydopamine(PD)can form a uniform nano-coating over the graphene/sulfur(G-S)surface and provide strong affinity to the cross-linked polyacrylamide(c-PAM)binder,thus tightly integrating sulfur with the binder network and greatly boosting the overall mechanical strength/conductivity of the electrode.Moreover,the PD coating and c-PAM binder rich in polar groups can form two effective blockades against the effusion of soluble polysulfides.As such,the 4.5 mg cm−2 sulfur-loaded G-S@PD-c-PAM cathode achieves a capacity of 480 mAh g−1 after 300 cycles at 1 C,while maintaining a capacity of 396 mAh g−1 after 50 cycles at 0.2 C when the sulfur loading rises to 9.1 mg cm−2.This work provides a system-wide concept for constructing high-loading sulfur cathodes through integrated structural design.
基金Sponsored by the Heilongjiang Provincial Project(Grant No.12511121)the Harbin City Innovation Talent Project(Grant No.2011RFXXG019)the National Science and Technology Support Project(Grant No.2012BAH28F02)
文摘In this paper,high-power LED with many integrated chips is used as thermal resistance analysis research object, and we do thermal resistance testing technology research on it. We put forward the thermocouple point contact test method. According to the principle that LED forward voltage changes with temperature,LED heat sink to surface temperature distribution is studied directly in the test,and then we analyze the thermal resistance of high-power LED with many integrated chips when its secondary packaging is introduced. This method makes the measurement of thermal resistance of LED more rapid and convenient. It provides an effective assessment method for the analysis of high power LED device design and engineering application.
基金Natural Science Foundation of Hebei Province(China),Grant/Award Numbers:B2020203013,B2021203016Science and Technology Project of Hebei Education Department(China),Grant/Award Number:QN2020137+3 种基金Cultivation Project for Basic Research Innovation of Yanshan University(China),Grant/Award Number:2021LGZD015Subsidy for Hebei Key Laboratory of Applied Chemistry after Operation Performance(China),Grant/Award Number:22567616HNatural Science Foundation of Heilongjiang Province(China),Grant/Award Number:LH2022B025Fundamental Research Funds for the Provincial Universities of Heilongjiang Province(China),Grant/Award Number:KYYWF10236190104。
文摘Colorless‐to‐black switching has attracted widespread attention for smart windows and multifunctional displays because they are more useful to control solar energy.However,it still remains a challenge owing to the tremendous difficulties in the design of completely reverse absorptions in transmissive and colored states.Herein,we report on an electrochemical device that can switch between colorless and black by using the electrochemical process of hybrid organic–inorganic perovskite MAPbBr_(3),which shows a high integrated contrast ratio of up to 73%from 400 to 800 nm.The perovskite solution can be used as the active layer to assemble the device,showing superior transmittance over the entire visible region in neutral states.By applying an appropriate voltage,the device undergoes reversible switching between colorless and black,which is attributed to the formation of lead and Br_(2)in the redox reaction induced by the electron transfer process in MAPbBr_(3).In addition,the contrast ratio can be modulated over the entire visible region by changing the concentration and the applied voltage.These results contribute toward gaining an insightful understanding of the electrochemical process of perovskites and greatly promoting the development of switchable devices.
文摘To make high integrity lightweight metal castings,best practices are required in various stages of casting and heat treatment processes,including liquid metal composition and quality control,casting and gating/riser system design,and process optimization.This paper presents best practices for liquid metal processing and quality assurance of molten metal in both melting and mold filling.Best practices for other aspects of lightweight metal casting will be published separately.
基金Project(50605023) supported by the National Natural Science Foundation of China
文摘Plowing-extruding tool was designed and plowing-extruding process was investigated.Then,a manufacturing method of integral serrated high-finned tube,plowing-extruding based on variational feed was proposed,in which plowing-extruding tool moved forward at two different feeds,f1 and f2,in turn.In this method,overlaps that are usually avoided in practical application were utilized to manufacture high fins and average height of fins was up to 1.58 mm.The critical feed(fc) of overlaps forming and terms of high fins forming were analyzed.The main technical parameters that affect the fins height were discussed.The experimental results show that the fins height increases with extruding inclination angle and plowing-extruding depth,and the fins height increases with f1 increasing when f1 is smaller than fc,and decreases with f1 increasing if f1 is larger than fc.
基金supported by the National Natural Science Foundation of China(Grant No.50876066)
文摘It is always a bottleneck to design an effective algorithm for linear time-varying systems in engineering applications.For a class of systems,whose coefficients matrix is based on time-varying polynomial,a modified highly precise direct integration(VHPD-T method)was presented.Through introducing new variables and expanding dimensions,the system can be transformed into a timeinvariant system,in which the transfer matrix can be computed for once and used forever with a highly precise direct integration method.The method attains higher precision than the common methods(e.g.RK4 and power series)and high efficiency in computation.Some numerical examples demonstrate the validity and efficiency of the method proposed.
基金supported by the National Natural Science Foundation of China (No. 10662003)the Doctoral Fund of Ministry of Education of China (No. 20040787013)
文摘Based on the linear theories of thin cylindrical shells and viscoelastic materials, a governing equation describing vibration of a sandwich circular cylindrical shell with a viscoelastic core under harmonic excitation is derived. The equation can be written as a matrix differential equation of the first order, and is obtained by considering the energy dissipation due to the shear deformation of the viscoelastic core layer and the interaction between all layers. A new matrix method for solving the governing equation is then presented With an extended homogeneous capacity precision integration approach. Having obtained these, vibration characteristics and damping effect of the sandwich cylindrical shell can be studied. The method differs from a recently published work as the state vector in the governing equation is composed of displacements and internal forces of the sandwich shell rather than displacements and their derivatives. So the present method can be applied to solve dynamic problems of the kind of sandwich shells with various boundary conditions and partially constrained layer damping. Numerical examples show that the proposed approach is effective and reliable compared with the existing methods.
基金supported by the National Natural Science Foun-dation of China (11172334)
文摘This paper presents a high order symplectic con- servative perturbation method for linear time-varying Hamil- tonian system. Firstly, the dynamic equation of Hamilto- nian system is gradually changed into a high order pertur- bation equation, which is solved approximately by resolv- ing the Hamiltonian coefficient matrix into a "major compo- nent" and a "high order small quantity" and using perturba- tion transformation technique, then the solution to the orig- inal equation of Hamiltonian system is determined through a series of inverse transform. Because the transfer matrix determined by the method in this paper is the product of a series of exponential matrixes, the transfer matrix is a sym- plectic matrix; furthermore, the exponential matrices can be calculated accurately by the precise time integration method, so the method presented in this paper has fine accuracy, ef- ficiency and stability. The examples show that the proposed method can also give good results even though a large time step is selected, and with the increase of the perturbation or- der, the perturbation solutions tend to exact solutions rapidly.
基金Project supported by the National Natural Science Foundation of China(Grant No.61675041)the National Science Funds for Creative Research Groups of China(Grant No.61421002)
文摘Organic optoelectronic integrated devices(OIDs) with ultraviolet(UV) photodetectivity and different color emitting were constructed by using a thermally activated delayed fluorescence(TADF) material 4, 5-bis(carbazol-9-yl)-1, 2-dicyanobenzene(2 CzPN) as host. The OIDs doping with typical red phosphorescent dye [tris(1-phenylisoquinoline)iridium(Ⅲ), Ir(piq)3], orange phosphorescent dye {bis[2-(4-tertbutylphenyl)benzothiazolato-N,C-(2')]iridium(acetylacetonate),(tbt)2 Ir(acac)}, and blue phosphorescent dye [bis(2, 4-di-fluorophenylpyridinato)-tetrakis(1-pyrazolyl)borate iridium(Ⅲ), FIr6] were investigated and compared. The(tbt)2 Ir(acac)-doped orange device showed better performance than those of red and blue devices, which was ascribed to more effective energy transfer. Meanwhile, at a low dopant concentration of 3 wt.%, the(tbt)2 Ir(acac)-doped OIDs showed the maximum luminance, current efficiency, power efficiency of 70786 cd/m^2, 39.55 cd/A, and 23.92 lm/W, respectively, and a decent detectivity of 1.07 × 10^11 Jones at a bias of -2 V under the UV-350 nm illumination. This work may arouse widespread interest in constructing high efficiency and luminance OIDs based on doping phosphorescent dye.
文摘When kernel density is in the class of continuous function to possessing sufficient derivative of high order(and needn't in the class of corresponding Holder function),in this paper it is given the continuity and the differential formulas for singular integrals of high non--integral order. The above results themselves and in order to prove in future the formulas to changing order of integration for singular integrals of high non-integral order(another paper) will have important significance. The method to prove in this paper is more different from the method in the corresponding cass of singular integrals of high integral order.
文摘Based on the differ—ent theories,TCM andWestern medicine(WM)have their owndifferent understandingsabout the pathogenesisand treatment of highblood pressure(HBP).In TCM the balancesbetween blood-qi,vis—cera—bowel, and yin—yang are all highly
基金Supported by the National Key Basic Research Program of China under Grant No 2013CB921800the National Natural Science Foundation of China under Grant Nos 11227901,91021005,11274299,11104262 and 10834005the Strategic Priority Research Program(B)of the Chinese Academy of Sciences under Grant No XDB01030400
文摘Break junctions are important in generating nanosensors and single molecular devices. The mechanically con- trollable break junction is the most widely used method for a break junction due to its simplicity and stability. However, the bandwidths of traditional devices are limited to about a few hertz. Moreover, when using traditional methods it is hard to allow independent control of more than one junction. Here we propose on-chip thermally controllable break junctions to overcome these challenges. This is verified by using finite element analysis. Adopting microelectromechanical systems produces features of high bandwidth and independent controllability to this new break junction system. The proposed method will have a wide range of applications on on-chip high speed independent controllable and highly integrated single molecule devices.
文摘<div style="text-align:justify;"> Transceiver module and two-dimensional sum difference network are important components of phased array antenna. In this paper, multilayer printed board is used to integrate millimeter wave multi-channel transceiver circuit and sum difference network. The interconnection between them is realized through RF coaxial vertical transition. At the same time, the heat dissipation design and inter channel shielding design of the module are carried out. The RF and low frequency required by the module are completed through the wiring between and within the dielectric plate layers. Finally, 128 arrays are fabricated and verified by multi-channel passive test. The results show that the type transceiver module integrating with two-dimensional sum difference network has good performance, and 128 channels have excellent amplitude and phase characteristics. The integration technology has the characteristics of lightweight, miniaturization, high integration and low manufacturing cost. It can be widely used in miniaturized phased array antennas. </div>
基金Supported by the Scientific Research Fund Project of the Education Department of Shaanxi Province under Grant No 15JK1732the Natural Science Foundation of Shaanxi Province under Grant No2014JQ1044the Science Foundation of Northwest University under Grant No 12NW01
文摘A high optical magnification three-dimensional imaging system is proposed using an optic microscope whose ocular (eyepiece) is retained and the structure of the transmission mode is not destroyed. The elemental image array is captured through the micro lens array. Due to the front diffuse transmission element, each micro lens sees a slightly different spatial perspective of the scene, and a different independent image is formed in each micro lens channel. Each micro lens channel is imaged by a Fourier lens and captured by a CCD. The design translating the stage in x or y provides no parallax. Compared with the conventional integral imaging of micro-objects, the optical magnification of micro-objects in the proposed system can enhanced remarkably. The principle of the enhancement of the image depth is explained in detail and the experimental results are presented.
文摘The lack of standard to electronic circuits modeling made possible the development of many tools and modeling languages for electronic circuits. In this way, several tools to be used on different descriptions stage of the designs are necessary. This paper presents a tool called SF^2HDL (Stateflow to Hardware Description Language or State Transition Table) that translates a finite state machine on state transition diagram representation, described by Stateflow tool, into an input file standard for TABELA program or into a file behavioral VHDL (Very High Speed Integrated Circuits Hardware Description Language) directly. The TABELA program was used to optimization this finite state machine. After that, the TAB2VHDL program was used to generate the VHDL code on register transfer level, what permits comparisons with results obtained by synthesis. The finite state machine must be described by Mealy model and the user can describe the machine on high level abstraction using all Simulink supports. The tool was very efficient on computational cost and it made translation of several cases, for the two VHDL description models. Every state machine translated was simulated and implemented on device EP2C20F484C7 using Quartus II environment.
文摘To meet the application requirements for a Ka-band space-based TT&C terminal for a launch vehicle,this paper proposes the implementation scheme of a space-based TT&C terminal,analyzes and solves the miniaturized design of equipment and the key technology for high-efficiency heat dissipation.The phased array antenna test shows that without external heat dissipation measures,the phased array antenna can work for a long time to meet the working requirements of launch vehicle,which has been verified in the LM-8 mission,and has wide engineering application prospects.
基金the National Key Research and Development Program of China(2021YFC2101000)the National Natural Science Foundation of China(32301220).
文摘The chromosomal position effect can significantly affect the transgene expression,which may provide an efficient strategy for the inauguration of alien genes in new hosts,but has been less explored rationally.The bacterium Myxococcus xanthus harbors a large circular high-GC genome,and the position effect in this chassis may result in a thousand-fold expression variation of alien natural products.In this study,we conducted transposon insertion at TA sites on the M.xanthus genome,and used enrichment and dilution indexes to respectively appraise high and low expression potentials of alien genes at insertion sites.The enrichment sites are characteristically distributed along the genome,and the dilution sites are overlapped well with the horizontal transfer genes.We experimentally demonstrated the enrichment sites as high expression integration sites(HEISs),and the dilution sites unsuitable for gene integration expression.This work highlights that HEISs are the plug-and-play sites for efficient expression of integrated genes.
基金NSFC,Grant/Award Numbers:22075019,22035005National Key R&D Program of China,Grant/Award Number:2017YFB1104300。
文摘The vigorous development in the field of energy conversion and storage devices directly contributes to the full utilization and convenient use of clean energy.However,some drawbacks of independent energy conversion and storage devices,including unstable,insufficient energy output and dependence on external power supply,are difficult to overcome by self-optimization,thus,hindering their further development and direct application.Coincidentally,the combination of above two devices can solve these problems,which conforms to their intrinsic needs for development.At the same time,the pursuit of portability and miniaturization also promotes the development of the power system toward a highly integrated direction.Therefore,we introduce several integration modes of energy conversion and storage systems,with emphasis on all-in-one power system,possessing the highest integration in this review.From the aspect of device configuration,working mechanisms and their performances,the all-inone power systems based on different energy sources(e.g.,mechanical,solar,thermal,and chemical energy)are discussed and analyzed.Finally,the design strategies are summarized and the potential development directions in the future are proposed.This review aims to provide a comprehensive overview of highly integrated energy conversion and storage system,and seeks to point out the opportunities and orientations of future research in this field.