Interdigitation means mutual nappe structures which might result from the low-angle thrusting during the collision betWeen tWo continental blocks. It is well developed in the coveting strata of Laochang-Laba district,...Interdigitation means mutual nappe structures which might result from the low-angle thrusting during the collision betWeen tWo continental blocks. It is well developed in the coveting strata of Laochang-Laba district, Lancang, Yunnan Province ( Fig. 1).展开更多
In the rapidly evolving field of modern technology,near-infrared(NIR)photodetectors are extremely crucial for efficient and reliable optical communications.The graphene/GaAs Schottky junction photodetector leverages g...In the rapidly evolving field of modern technology,near-infrared(NIR)photodetectors are extremely crucial for efficient and reliable optical communications.The graphene/GaAs Schottky junction photodetector leverages graphene’s exceptional carrier mobility and broadband absorption,coupled with GaAs’s strong absorption in the NIR spectrum,to achieve high responsivity and rapid response times.Here,we present a NIR photodetector employing a graphene/GaAs Schottky junction tailored for communication wavelengths.We fabricated high-performance graphene/GaAs Schottky junction devices with interdigitated electrodes of varying finger widths,systematically investigating their impact on device performance.The experimental results demonstrate that incorporating interdigitated electrodes significantly enhances the collection efficiency of photogenerated carriers in graphene/GaAs photodetectors.When illuminated by 808 nm NIR light at an intensity of 7.23 mW/cm^(2),the device achieves an impressive switch ratio of 10^(7),along with a high responsivity of 40.1 mA/W and a remarkable detectivity of 2.89×10^(13)Jones.Additionally,the device is characterized by rapid response times,with rise and fall times of 18.5 and 17.5μs,respectively,at a 3 dB bandwidth.These findings underscore the significant potential of high-performance graphene/GaAs photodetectors for applications in NIR optoelectronic systems.展开更多
Two Zn（II） coordination polymers, namely [Zn2（bpy）（aobtc）（H2O）2]·2H2O（1） and [Zn2（bpy）（aobtc）（H2O）]·4H2O（2）（bpy = 4,4＇-bipyridine, H4 aobtc = 3,3＇,5,5＇-azoxybenzenetetracarboxylic acid...Two Zn（II） coordination polymers, namely [Zn2（bpy）（aobtc）（H2O）2]·2H2O（1） and [Zn2（bpy）（aobtc）（H2O）]·4H2O（2）（bpy = 4,4＇-bipyridine, H4 aobtc = 3,3＇,5,5＇-azoxybenzenetetracarboxylic acid） have been hydrothermally synthesized through tuning the p H value of the reaction system（1, C（26）H（22）N（4）O（13）Zn2, Mr = 729.21; 2, C（26）H（24）N4O（14）Zn2, Mr = 747.23）, and their structures have been determined by single-crystal X-ray diffraction analyses. Compound 2 has been further characterized by infrared spectra（IR）, elemental analyses, thermal analyses and powder X-ray diffraction（PXRD） analyses. Additionally, the photoluminescence of 2 is also discussed. The structure demonstrates that the crystal of 2 belongs to the triclinic system, space group P1 with a = 8.41494（18）, b = 9.59838（19）, c = 17.6477（3） ？, α = 91.5098（16）, β = 98.1439（17）, γ = 90.4323（17）°, V = 1410.44（5） ^3, Z = 2, ρcalc = 1.759 g/cm^3, μ = 2.819 mm-1, F（000） = 760.0, R = 0.0311 and w R = 0.0839（I 〉 2σ（I））. Compound 1 shows a two-dimensional monolayer while compound 2 displays a novel 2D double-layered network constructed from monolayer motifs, which is similar to the single layer in 1. Further, each bilayer motif in 2 is interdigitated by two others in a parallel fashion to yield an unusual 2D → 3D interdigitated framework.展开更多
Performance of the proton exchange membrane fuel cell(PEMFC)is appreciably affected by the channel geometry.The branching structure of a plant leaf and human lung is an efficient network to distribute the nutrients in...Performance of the proton exchange membrane fuel cell(PEMFC)is appreciably affected by the channel geometry.The branching structure of a plant leaf and human lung is an efficient network to distribute the nutrients in the respective systems.The same nutrient transport system can be mimicked in the flow channel design of a PEMFC,to aid even reactant distribution and better water management.In this work,the effect of bio-inspired flow field designs such as lung and leaf channel design bipolar plates,on the performance of a PEMFC was examined experimentally at various operating conditions.A PEMFC of 49 cm2 area,with a Nafion 212 membrane with a 40%catalyst loading of 0.4 mg·cm-2 on the anode side and also 0.6 mg·cm-2 on the cathode side is assembled by incorporating the bio-inspired channel bipolar plate,and was tested on a programmable fuel-cell test station.The impact of the working parameters like reactants’relative humidity(RH),back pressure and fuel cell temperature on the performance of the fuel cell was examined;the operating pressure remains constant at 0.1 MPa.It was observed that the best performance was attained at a back pressure of 0.3 MPa,75°C operating temperature and 100%RH.The three flow channels were also compared at different operating pressures ranging from 0.1 MPa to 0.3 MPa,and the other parameters such as operating temperature,RH and back pressure were set as 75°C,100%and 0.3 MPa.The experimental outcomes of the PEMFC with bio-inspired channels were compared with the experimental results of a conventional triple serpentine flow field.It was observed that among the different flow channel designs considered,the leaf channel design gives the best output in terms of power density.Further,the experimental results of the leaf channel design were compared with those of the interdigitated leaf channel design.The PEMFC with the interdigitated leaf channel design was found to generate 6.72%more power density than the non-interdigitated leaf channel design.The fuel cell with interdigitated leaf channel design generated5.58%more net power density than the fuel cell with non-interdigitated leaf channel design after considering the parasitic losses.展开更多
Rapid screening of foodborne pathogens is of great significance to ensure food safety.A microfluidic biosensor based on immunomagnetic separation,enzyme catalysis and electrochemical impedance analysis was developed f...Rapid screening of foodborne pathogens is of great significance to ensure food safety.A microfluidic biosensor based on immunomagnetic separation,enzyme catalysis and electrochemical impedance analysis was developed for rapid and sensitive detection of S.typhimurium.First,the bacterial sample,the magnetic nanoparticles(MNPs)modified with capture antibodies,and the enzymatic probes modified with detection antibodies and glucose oxidase(GOx)were simultaneously injected into the microfluidic chip,followed by mixing and incubation to form MNP-bacteria-probe sandwich complexes.Then,glucose with high impedance was injected into the chip and catalyzed by the GOx on the complexes into hydrogen peroxide with high impedance and gluconic acid with low impedance,which was finally measured using the low-cost interdigitated microelectrode and the electrochemical impedance analyzer to determine the target bacteria.Under the optimal conditions,this biosensor could quantitatively detect S.typhimurium at the concentrations from 1.6×10^(2) CFU/m L to 1.6×10^(6) CFU/m L in 1 h with the low detection limit of 73 CFU/m L.Besides,this biosensor was demonstrated with good feasibility for practical applications by detecting the S.typhimurium spiked chicken meat samples.展开更多
A numerical model for proton exchange membrane (PEM) fuel cell is developed, which can simulate such basic transport phenomena as gas-liquid two-phase flow in a working fuel cell. Boundary conditions for both the conv...A numerical model for proton exchange membrane (PEM) fuel cell is developed, which can simulate such basic transport phenomena as gas-liquid two-phase flow in a working fuel cell. Boundary conditions for both the conventional and the interdigitated modes of flow are presented on a three-dimensional basis. Numerical techniques for this model are discussed in detail. Validation shows good agreement between simulating results and experimental data. Furthermore, internal transport phenomena are discussed and compared for PEM fuel cells with conventional and interdigitated flows. It is found that the dead-ended structure of an interdigitated flow does increase the oxygen mass fraction and decrease the liquid water saturation in the gas diffusion layer as compared to the conventional mode of flow. However, the cathode humidification is important for an interdigitated flow to acquire better performance than a conventional flow fuel cell.展开更多
Wearable supercapacitors(SCs)are gaining prominence as portable energy storage devices.To develop high-performance wearable SCs,the significant relationship among material,structure,and performance inspired us with a ...Wearable supercapacitors(SCs)are gaining prominence as portable energy storage devices.To develop high-performance wearable SCs,the significant relationship among material,structure,and performance inspired us with a delicate design of the highly wearable embroidered supercapacitors made from the conductive fibers composited.By rendering the conductive interdigitally patterned embroidery as both the current collector and skeleton for the SCs,the novel pseudocapacitive material cobalt phosphides were then successfully electrodeposited,forming the first flexible and wearable in-plane embroidery SCs.The electrochemical measurements manifested that the highest specific capacitance was nearly 156.6 mF cm?2(65.72 F g?1)at the current density of 0.6 mA cm?2(0.25 A g?1),with a high energy density of 0.013 mWh cm?2(5.55 Wh kg?1)at a power density of 0.24 mW cm?2(100 W kg?1).As a demonstration,a monogrammed pattern was ingeniously designed and embroidered on the laboratory gown as the wearable in-plane SCs,which showed both decent electrochemical performance and excellent flexibility.展开更多
A compact interdigital H-mode drift-tube linac (IH-DTL) with the alternating-phase-focusing (APF) method, working at 325 MHz was designed for an injector of a proton medical accelerator. When fed in with a proper RF (...A compact interdigital H-mode drift-tube linac (IH-DTL) with the alternating-phase-focusing (APF) method, working at 325 MHz was designed for an injector of a proton medical accelerator. When fed in with a proper RF (radio frequency) power, the DTL cavity could establish the corresponding electromagnetic field to accelerate the ‘‘proton bunches’’ from an input energy of 3 MeV to an output energy of 7 MeV successfully, without any additional radial focusing elements. The gap-voltage distribution which was obtained from the CST■ Microwave Studio software simulations of the axial electric field was compared with that from the beam dynamics, and the errors met the requirements within ± 5%. In this paper, the RF design procedure and key results of the APF IH-DTL, which include the main RF characteristics of the cavity, frequency sensitivities of the tuners, and coupling factor of the RF power input coupler are presented.展开更多
Interdigitated back contact silicon hetero-junction(IBC-SHJ) solar cells exhibit excellent performance owing to the IBC and SHJ structures.The front surface field(FSF) layer composed of electric field passivation and ...Interdigitated back contact silicon hetero-junction(IBC-SHJ) solar cells exhibit excellent performance owing to the IBC and SHJ structures.The front surface field(FSF) layer composed of electric field passivation and chemical passivation has been proved to play an important role in IBC-SHJ solar cells.The electric field passivated layer n^+-a-Si: H, an n-type Si alloy with carbon or oxygen in amorphous phase, is simulated in this study to investigate its effect on IBC-SHJ.It is indicated that the n^+-a-Si: H layer with wider band gap can reduce the light absorption on the front side efficaciously,which hinders the surface recombination of photo-generated carriers and thus contributes to the improvement of the short circuit current density Jsc.The highly doped n^+-a-Si: H can result in the remakable energy band bending, which makes it outstanding in the field passivation, while it makes little contribution to the chemical passivation.It is noteworthy that when the electric field intensity exceeds 1.3 × 10^5 V/cm, the efficiency decrease caused by the inferior chemical passivation is only 0.16%.In this study, the IBC-SHJ solar cell with a front n^+-a-Si: H field passivation layer is simulated, which shows the high efficiency of 26% in spite of the inferior chemical passivation on the front surface.展开更多
Lamb waves are used to detect fouling in food vessels. The propagation of the Lamb waves in plates exhibits many modes and dispersion characteristics, which have great influence on fouling detection. The relative dist...Lamb waves are used to detect fouling in food vessels. The propagation of the Lamb waves in plates exhibits many modes and dispersion characteristics, which have great influence on fouling detection. The relative distribution of the in-plane and out-of-plane displacement of the mode across the thickness of the plate will determine the sensitivity of the mode to a particular loading condition. By considering the dispersion and multi-mode characteristics of guided waves, an interdigital polyvi- nylidene fluoride （PVDF） transducer is designed to realize the mode selection of gnided waves, and a single a0 mode is used for guided wave detection. Fouling detection experiments are conducted in the laboratory using epoxy adhesive on a thin plate. Using the interdigital PVDF transducer, three fouled areas are detected. Using one of the time-frequency analysis methods, the waveforms are further processed. This also demonstrates the validity of this method of fouling detection.展开更多
Flexible pressure sensors have many potential applications in the monitoring of physiological signals because of their good biocompatibil-ity and wearability.However,their relatively low sensitivity,linearity,and stab...Flexible pressure sensors have many potential applications in the monitoring of physiological signals because of their good biocompatibil-ity and wearability.However,their relatively low sensitivity,linearity,and stability have hindered their large-scale commercial application.Herein,aflexible capacitive pressure sensor based on an interdigital electrode structure with two porous microneedle arrays(MNAs)is pro-posed.The porous substrate that constitutes the MNA is a mixed product of polydimethylsiloxane and NaHCO3.Due to its porous and interdigital structure,the maximum sensitivity(0.07 kPa-1)of a porous MNA-based pressure sensor was found to be seven times higher than that of an imporous MNA pressure sensor,and it was much greater than that of aflat pressure sensor without a porous MNA structure.Finite-element analysis showed that the interdigital MNA structure can greatly increase the strain and improve the sensitivity of the sen-sor.In addition,the porous MNA-based pressure sensor was found to have good stability over 1500 loading cycles as a result of its bilayer parylene-enhanced conductive electrode structure.Most importantly,it was found that the sensor could accurately monitor the motion of afinger,wrist joint,arm,face,abdomen,eye,and Adam’s apple.Furthermore,preliminary semantic recognition was achieved by monitoring the movement of the Adam’s apple.Finally,multiple pressure sensors were integrated into a 33 array to detect a spatial pressure distribu-×tion.Compared to the sensors reported in previous works,the interdigital electrode structure presented in this work improves sensitivity and stability by modifying the electrode layer rather than the dielectric layer.展开更多
The n-type silicon integrated-back contact（IBC） solar cell has attracted much attention due to its high efficiency,whereas its performance is very sensitive to the wafer of low quality or the contamination during hi...The n-type silicon integrated-back contact（IBC） solar cell has attracted much attention due to its high efficiency,whereas its performance is very sensitive to the wafer of low quality or the contamination during high temperature fabrication processing, which leads to low bulk lifetime τbulk. In order to clarify the influence of bulk lifetime on cell characteristics, two-dimensional（2D） TCAD simulation, combined with our experimental data, is used to simulate the cell performances, with the wafer thickness scaled down under various τbulk conditions. The modeling results show that for the IBC solar cell with high τbulk,（such as 1 ms-2 ms）, its open-circuit voltage V oc almost remains unchanged, and the short-circuit current density J sc monotonically decreases as the wafer thickness scales down. In comparison, for the solar cell with low τbulk（for instance, 〈 500 μs） wafer or the wafer contaminated during device processing, the V oc increases monotonically but the J sc first increases to a maximum value and then drops off as the wafer＇s thickness decreases. A model combing the light absorption and the minority carrier diffusion is used to explain this phenomenon. The research results show that for the wafer with thinner thickness and high bulk lifetime, the good light trapping technology must be developed to offset the decrease in J sc.展开更多
We investigate the focusing phenomena of a surface acoustic wave （SAW） field generated by a circular-arc interdigital transducer （IDT） on a piezoelectric crystal. A rigorous vector field theory of surface excitati...We investigate the focusing phenomena of a surface acoustic wave （SAW） field generated by a circular-arc interdigital transducer （IDT） on a piezoelectric crystal. A rigorous vector field theory of surface excitation on the crystal we developed previously is used to evaluate the convergent SAW field instead of the prevalent scalar angular spectrum used in optics. The theoretical results show that the anisotropy of a medium has great impact on the focusing properties of the acoustic beams, such as focal length and symmetrical distributions near the focus. A dark field method is used in experiment to observe the focusing of the SAW tield optically. Although the convergent phenomena of SAW field on the anisotropic media or piezoelectric crystals are very complicated, the experimental data are in agreement with those from the rigorous theory.展开更多
In this paper,pure polyaniline (PAN:Emeraldine base (EB) form) films and the mixed LB films of PAN and acetic acid (AA) with various layers were prepared by Langmuir-Blodgett (LB) technique.PAN based gas sensors wer...In this paper,pure polyaniline (PAN:Emeraldine base (EB) form) films and the mixed LB films of PAN and acetic acid (AA) with various layers were prepared by Langmuir-Blodgett (LB) technique.PAN based gas sensors were fabricated by deposited PAN based LB thin films on the interdigitated electrodes.The gas-sensitivity to NO_2 of PAN based gas sensors with different layers was studied.It is found that pure polyaniline LB films present higher sensitivity,responsivity and reversibility to NO_2 gas compared with polyaniline and acetic acid mixed LB films.The response time of 3-layer and 15-layer pure polyaniline LB films to 20μg/g NO_2 gas is about 10 s and 30 s,respectively.The recovery time of the 15-layer pure polyaniline LB films is close to 5 min.展开更多
The Cl2-sensitive heteropolysiloxanes(HPS) film was formed on the interdigital capacitor based on silicon dioxide by means of sol-gel process and spin-on technique.Measurements of interdigital capacitance were perform...The Cl2-sensitive heteropolysiloxanes(HPS) film was formed on the interdigital capacitor based on silicon dioxide by means of sol-gel process and spin-on technique.Measurements of interdigital capacitance were performed at room temperature for frequencies 100 Hz,1 kHz and 10 kHz.It is shown that there is a linear relationship between the capacitance and the concentration of chlorine gas.Influences of the measurement frequency and film thickness of silicate on the sensitivity of the sensor to C12 gas were discussed.And organically modified N,N-diethylaminopropyl-trimethoxysilane (APMS) had a much higher sensitivity.展开更多
With the principles of microwave circuits and semiconductor device physics,three kinds of microwave power device test circuits are designed and simulated,whose properties are evaluated by a parameter network analyzer ...With the principles of microwave circuits and semiconductor device physics,three kinds of microwave power device test circuits are designed and simulated,whose properties are evaluated by a parameter network analyzer within the frequency range from 3 to 8GHz.The simulated results verify that the test circuit with stepped-impedance filter bias network has a larger bandwidth than that with the radial stub.A microstrip interdigital capacitor is used in the third test circuit to replace the DC block,however,which does not show its advantage during the test frequency band.Based on the simulated results,the stepped-impedance filter test circuit can be used to evaluate microwave power devices in the whole C band,namely from 4 to 8GHz.展开更多
The electro-mechanical coupling behaviors of ferroelectric devices with interdigital electrodes may become complicated due to the material inhomogeneity and local field concentration under the complex working conditio...The electro-mechanical coupling behaviors of ferroelectric devices with interdigital electrodes may become complicated due to the material inhomogeneity and local field concentration under the complex working conditions.In this paper,a ferroelectric model,drawn from the typical interdigital electrode structure of a ferroelectric sensor,is established based on phase field theory,to study the polarization evolution and explore the evolution laws in ferroelectrics.Numerical results show that there appears ferroelectric creep even under an applied electric field below the coercive field value.Also,the configurational force theory is introduced to investigate the mechanical behaviors related to polarization switching in the ferroelectric samples with interdigital electrodes.It is found that configurational force and polarization have similar evolution laws in both time evolving and space distribution.And considering the configurational force as the driving force,it is possible to predict the potential direction of polarization evolution and explore its evolution mechanism in ferroelectrics,demonstrating the configurational force as a useful parameter for describing mechanical behavior during the polarization evolution and a powerful tool for investigating the evolution mechanism of microstructure with coupling effects in ferroelectric materials.展开更多
High-density horizontal InAs nanowire transistors are fabricated on the interdigital silicon-on-insulator substrate.Hexagonal InAs nanowires are uniformly grown between face-to-face（111） vertical sidewalls of neighb...High-density horizontal InAs nanowire transistors are fabricated on the interdigital silicon-on-insulator substrate.Hexagonal InAs nanowires are uniformly grown between face-to-face（111） vertical sidewalls of neighboring Si fingers by metal–organic chemical vapor deposition. The density of InAs nanowires is high up to 32 per group of silicon fingers,namely an average of 4 nanowires per micrometer. The electrical characteristics with a higher on/off current ratio of 2×10~5are obtained at room temperature. The silicon-based horizontal InAs nanowire transistors are very promising for future high-performance circuits.展开更多
Currently,the increasing demands for portable,implantable,and wearable electronics have triggered the interest in miniaturized energy storage devices.Different from conventional energy storage devices,interdigital mic...Currently,the increasing demands for portable,implantable,and wearable electronics have triggered the interest in miniaturized energy storage devices.Different from conventional energy storage devices,interdigital microbatteries(IMBs) are free of separators and prepared on a single substrate,potentially achieving a short ionic diffusion path and better performance.Meanwhile,they can be easily fabricated and integrated into on-chip miniaturized electronics,holding the promise to provide long-lasting power for advanced microelectronic devices.To date,while many seminal works have been reviewed the topic of microbatteries,there is no work that systematically summarizes the development of IMBs of high energy density and stable voltage platforms from fabrication,functionalization to integration.The current review focuses on the most recent progress in IMBs,discussing advanced micromachining techniques with compatible features to construct high-performance IMBs with smart functions and intelligent integrated systems.The future opportunities and challenges of IMBs are also highlighted,calling for more efforts in this dynamic and fast-growing research field.展开更多
Polymer-based materials with patterned functional particles have been used to develop smart devices with multiple functionalities.This paper presents a novel method to pattern microscale particles into biocompatible p...Polymer-based materials with patterned functional particles have been used to develop smart devices with multiple functionalities.This paper presents a novel method to pattern microscale particles into biocompatible polyethylene glycol diacrylate(PEGDA)fluid through a designed surface acoustic wave(SAW)device with slanted-finger interdigital transducers(SFITs).By applying signals of different frequencies,the SFITs can excite SAWs with various wavelengths to pattern the microscale particles.The structural design and working principle of the SAW device with SFITs are firstly presented.To investigate the generation of standing SAWs and pressure field distributions of the SAW device with SFITs,a numerical model was developed.Simulation results showed that different strip-shape patterned pressure fields can be generated,and the period and width of adjacent strips can be adjusted by changing the frequencies of the excitation signals.Experiments were performed to verify that the microscale particles in the PEGDA solution can be successfully patterned into strip-shape patterns with various positions,periods,and widths.The results obtained in this study demonstrate that the developed method of using an SAW device with SFITs can be used for tunable patterning of microscale particles in solutions,and shows great potential for biomedical and microfluidic applications.展开更多
基金This note is one of research fruits of the Project 9487002, supported by the National Natural Science Foundation of China.
文摘Interdigitation means mutual nappe structures which might result from the low-angle thrusting during the collision betWeen tWo continental blocks. It is well developed in the coveting strata of Laochang-Laba district, Lancang, Yunnan Province ( Fig. 1).
基金supported by the National Natural Science Foundation of China(62375279)Suzhou Industrial Science and Technology Program(SYG202340,SJC2023004)Distinguished Young Scholar Fund of Natural Science Foundation of Jiangsu Province(BK20240125).
文摘In the rapidly evolving field of modern technology,near-infrared(NIR)photodetectors are extremely crucial for efficient and reliable optical communications.The graphene/GaAs Schottky junction photodetector leverages graphene’s exceptional carrier mobility and broadband absorption,coupled with GaAs’s strong absorption in the NIR spectrum,to achieve high responsivity and rapid response times.Here,we present a NIR photodetector employing a graphene/GaAs Schottky junction tailored for communication wavelengths.We fabricated high-performance graphene/GaAs Schottky junction devices with interdigitated electrodes of varying finger widths,systematically investigating their impact on device performance.The experimental results demonstrate that incorporating interdigitated electrodes significantly enhances the collection efficiency of photogenerated carriers in graphene/GaAs photodetectors.When illuminated by 808 nm NIR light at an intensity of 7.23 mW/cm^(2),the device achieves an impressive switch ratio of 10^(7),along with a high responsivity of 40.1 mA/W and a remarkable detectivity of 2.89×10^(13)Jones.Additionally,the device is characterized by rapid response times,with rise and fall times of 18.5 and 17.5μs,respectively,at a 3 dB bandwidth.These findings underscore the significant potential of high-performance graphene/GaAs photodetectors for applications in NIR optoelectronic systems.
基金Financially supported by the National Natural Science Foundation of China(No.21571149)the Program for Chongqing Excellent Talents in University,the Fundamental Research Funds for the Central Universities(XDJK2013A027,XDJK2016C101)the Open Foundation of Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education(338080045)
文摘Two Zn（II） coordination polymers, namely [Zn2（bpy）（aobtc）（H2O）2]·2H2O（1） and [Zn2（bpy）（aobtc）（H2O）]·4H2O（2）（bpy = 4,4＇-bipyridine, H4 aobtc = 3,3＇,5,5＇-azoxybenzenetetracarboxylic acid） have been hydrothermally synthesized through tuning the p H value of the reaction system（1, C（26）H（22）N（4）O（13）Zn2, Mr = 729.21; 2, C（26）H（24）N4O（14）Zn2, Mr = 747.23）, and their structures have been determined by single-crystal X-ray diffraction analyses. Compound 2 has been further characterized by infrared spectra（IR）, elemental analyses, thermal analyses and powder X-ray diffraction（PXRD） analyses. Additionally, the photoluminescence of 2 is also discussed. The structure demonstrates that the crystal of 2 belongs to the triclinic system, space group P1 with a = 8.41494（18）, b = 9.59838（19）, c = 17.6477（3） ？, α = 91.5098（16）, β = 98.1439（17）, γ = 90.4323（17）°, V = 1410.44（5） ^3, Z = 2, ρcalc = 1.759 g/cm^3, μ = 2.819 mm-1, F（000） = 760.0, R = 0.0311 and w R = 0.0839（I 〉 2σ（I））. Compound 1 shows a two-dimensional monolayer while compound 2 displays a novel 2D double-layered network constructed from monolayer motifs, which is similar to the single layer in 1. Further, each bilayer motif in 2 is interdigitated by two others in a parallel fashion to yield an unusual 2D → 3D interdigitated framework.
文摘Performance of the proton exchange membrane fuel cell(PEMFC)is appreciably affected by the channel geometry.The branching structure of a plant leaf and human lung is an efficient network to distribute the nutrients in the respective systems.The same nutrient transport system can be mimicked in the flow channel design of a PEMFC,to aid even reactant distribution and better water management.In this work,the effect of bio-inspired flow field designs such as lung and leaf channel design bipolar plates,on the performance of a PEMFC was examined experimentally at various operating conditions.A PEMFC of 49 cm2 area,with a Nafion 212 membrane with a 40%catalyst loading of 0.4 mg·cm-2 on the anode side and also 0.6 mg·cm-2 on the cathode side is assembled by incorporating the bio-inspired channel bipolar plate,and was tested on a programmable fuel-cell test station.The impact of the working parameters like reactants’relative humidity(RH),back pressure and fuel cell temperature on the performance of the fuel cell was examined;the operating pressure remains constant at 0.1 MPa.It was observed that the best performance was attained at a back pressure of 0.3 MPa,75°C operating temperature and 100%RH.The three flow channels were also compared at different operating pressures ranging from 0.1 MPa to 0.3 MPa,and the other parameters such as operating temperature,RH and back pressure were set as 75°C,100%and 0.3 MPa.The experimental outcomes of the PEMFC with bio-inspired channels were compared with the experimental results of a conventional triple serpentine flow field.It was observed that among the different flow channel designs considered,the leaf channel design gives the best output in terms of power density.Further,the experimental results of the leaf channel design were compared with those of the interdigitated leaf channel design.The PEMFC with the interdigitated leaf channel design was found to generate 6.72%more power density than the non-interdigitated leaf channel design.The fuel cell with interdigitated leaf channel design generated5.58%more net power density than the fuel cell with non-interdigitated leaf channel design after considering the parasitic losses.
文摘Rapid screening of foodborne pathogens is of great significance to ensure food safety.A microfluidic biosensor based on immunomagnetic separation,enzyme catalysis and electrochemical impedance analysis was developed for rapid and sensitive detection of S.typhimurium.First,the bacterial sample,the magnetic nanoparticles(MNPs)modified with capture antibodies,and the enzymatic probes modified with detection antibodies and glucose oxidase(GOx)were simultaneously injected into the microfluidic chip,followed by mixing and incubation to form MNP-bacteria-probe sandwich complexes.Then,glucose with high impedance was injected into the chip and catalyzed by the GOx on the complexes into hydrogen peroxide with high impedance and gluconic acid with low impedance,which was finally measured using the low-cost interdigitated microelectrode and the electrochemical impedance analyzer to determine the target bacteria.Under the optimal conditions,this biosensor could quantitatively detect S.typhimurium at the concentrations from 1.6×10^(2) CFU/m L to 1.6×10^(6) CFU/m L in 1 h with the low detection limit of 73 CFU/m L.Besides,this biosensor was demonstrated with good feasibility for practical applications by detecting the S.typhimurium spiked chicken meat samples.
基金Supported by "985" Funds, Shanghai Jiaotong University, China.
文摘A numerical model for proton exchange membrane (PEM) fuel cell is developed, which can simulate such basic transport phenomena as gas-liquid two-phase flow in a working fuel cell. Boundary conditions for both the conventional and the interdigitated modes of flow are presented on a three-dimensional basis. Numerical techniques for this model are discussed in detail. Validation shows good agreement between simulating results and experimental data. Furthermore, internal transport phenomena are discussed and compared for PEM fuel cells with conventional and interdigitated flows. It is found that the dead-ended structure of an interdigitated flow does increase the oxygen mass fraction and decrease the liquid water saturation in the gas diffusion layer as compared to the conventional mode of flow. However, the cathode humidification is important for an interdigitated flow to acquire better performance than a conventional flow fuel cell.
基金The Hong Kong Polytechnic University for the funding support(Nos.1-YW1B,G-YBV2,and G-UACC).
文摘Wearable supercapacitors(SCs)are gaining prominence as portable energy storage devices.To develop high-performance wearable SCs,the significant relationship among material,structure,and performance inspired us with a delicate design of the highly wearable embroidered supercapacitors made from the conductive fibers composited.By rendering the conductive interdigitally patterned embroidery as both the current collector and skeleton for the SCs,the novel pseudocapacitive material cobalt phosphides were then successfully electrodeposited,forming the first flexible and wearable in-plane embroidery SCs.The electrochemical measurements manifested that the highest specific capacitance was nearly 156.6 mF cm?2(65.72 F g?1)at the current density of 0.6 mA cm?2(0.25 A g?1),with a high energy density of 0.013 mWh cm?2(5.55 Wh kg?1)at a power density of 0.24 mW cm?2(100 W kg?1).As a demonstration,a monogrammed pattern was ingeniously designed and embroidered on the laboratory gown as the wearable in-plane SCs,which showed both decent electrochemical performance and excellent flexibility.
基金supported by the National Key Research and Development Program of China(No.2016YFC0105408)
文摘A compact interdigital H-mode drift-tube linac (IH-DTL) with the alternating-phase-focusing (APF) method, working at 325 MHz was designed for an injector of a proton medical accelerator. When fed in with a proper RF (radio frequency) power, the DTL cavity could establish the corresponding electromagnetic field to accelerate the ‘‘proton bunches’’ from an input energy of 3 MeV to an output energy of 7 MeV successfully, without any additional radial focusing elements. The gap-voltage distribution which was obtained from the CST■ Microwave Studio software simulations of the axial electric field was compared with that from the beam dynamics, and the errors met the requirements within ± 5%. In this paper, the RF design procedure and key results of the APF IH-DTL, which include the main RF characteristics of the cavity, frequency sensitivities of the tuners, and coupling factor of the RF power input coupler are presented.
基金Project supported by the National Key Research Program of China(Grant Nos.2018YFB1500500 and 2018YFB1500200)the National Natural Science Foundation of China(Grant Nos.51602340,51702355,and 61674167)JKW Project,China(Grant No.31512060106)
文摘Interdigitated back contact silicon hetero-junction(IBC-SHJ) solar cells exhibit excellent performance owing to the IBC and SHJ structures.The front surface field(FSF) layer composed of electric field passivation and chemical passivation has been proved to play an important role in IBC-SHJ solar cells.The electric field passivated layer n^+-a-Si: H, an n-type Si alloy with carbon or oxygen in amorphous phase, is simulated in this study to investigate its effect on IBC-SHJ.It is indicated that the n^+-a-Si: H layer with wider band gap can reduce the light absorption on the front side efficaciously,which hinders the surface recombination of photo-generated carriers and thus contributes to the improvement of the short circuit current density Jsc.The highly doped n^+-a-Si: H can result in the remakable energy band bending, which makes it outstanding in the field passivation, while it makes little contribution to the chemical passivation.It is noteworthy that when the electric field intensity exceeds 1.3 × 10^5 V/cm, the efficiency decrease caused by the inferior chemical passivation is only 0.16%.In this study, the IBC-SHJ solar cell with a front n^+-a-Si: H field passivation layer is simulated, which shows the high efficiency of 26% in spite of the inferior chemical passivation on the front surface.
基金This project is supported by National Natural Science Foundation of China (No. 60404017)Municipal Natural Science Foundation of Beijing, China (No.4052008)Plan of Excellent People Cultivation of Beijing, China (No. 20051D0501506)
文摘Lamb waves are used to detect fouling in food vessels. The propagation of the Lamb waves in plates exhibits many modes and dispersion characteristics, which have great influence on fouling detection. The relative distribution of the in-plane and out-of-plane displacement of the mode across the thickness of the plate will determine the sensitivity of the mode to a particular loading condition. By considering the dispersion and multi-mode characteristics of guided waves, an interdigital polyvi- nylidene fluoride （PVDF） transducer is designed to realize the mode selection of gnided waves, and a single a0 mode is used for guided wave detection. Fouling detection experiments are conducted in the laboratory using epoxy adhesive on a thin plate. Using the interdigital PVDF transducer, three fouled areas are detected. Using one of the time-frequency analysis methods, the waveforms are further processed. This also demonstrates the validity of this method of fouling detection.
基金supported in part by the National Natural Science Foundation of China(Grant No.62104056)the Zhejiang Provincial Natural Science Foundation of China(Grant No.LQ21F010010)+4 种基金the National Natural Science Foundation of China(Grant Nos.62141409 and 62204204)the National Key R&D Program of China(Grant No.2022ZD0208602)the Zhejiang Provincial Key Research&Development Fund(Grant Nos.2019C04003 and 2021C01041)the Shanghai Sailing Program(Grant No.21YF1451000)the Key Research and Development Program of Shaanxi(Grant No.2022GY-001).
文摘Flexible pressure sensors have many potential applications in the monitoring of physiological signals because of their good biocompatibil-ity and wearability.However,their relatively low sensitivity,linearity,and stability have hindered their large-scale commercial application.Herein,aflexible capacitive pressure sensor based on an interdigital electrode structure with two porous microneedle arrays(MNAs)is pro-posed.The porous substrate that constitutes the MNA is a mixed product of polydimethylsiloxane and NaHCO3.Due to its porous and interdigital structure,the maximum sensitivity(0.07 kPa-1)of a porous MNA-based pressure sensor was found to be seven times higher than that of an imporous MNA pressure sensor,and it was much greater than that of aflat pressure sensor without a porous MNA structure.Finite-element analysis showed that the interdigital MNA structure can greatly increase the strain and improve the sensitivity of the sen-sor.In addition,the porous MNA-based pressure sensor was found to have good stability over 1500 loading cycles as a result of its bilayer parylene-enhanced conductive electrode structure.Most importantly,it was found that the sensor could accurately monitor the motion of afinger,wrist joint,arm,face,abdomen,eye,and Adam’s apple.Furthermore,preliminary semantic recognition was achieved by monitoring the movement of the Adam’s apple.Finally,multiple pressure sensors were integrated into a 33 array to detect a spatial pressure distribu-×tion.Compared to the sensors reported in previous works,the interdigital electrode structure presented in this work improves sensitivity and stability by modifying the electrode layer rather than the dielectric layer.
基金Project supported by the Chinese Ministry of Science and Technology Projects(Grant Nos.2012AA050304 and Y0GZ124S01)the National Natural Science Foundation of China(Grant Nos.11104319,11274346,51202285,51402347,and 51172268)the Fund of the Solar Energy Action Plan from the Chinese Academy of Sciences(Grant Nos.Y3ZR044001 and Y2YF014001)
文摘The n-type silicon integrated-back contact（IBC） solar cell has attracted much attention due to its high efficiency,whereas its performance is very sensitive to the wafer of low quality or the contamination during high temperature fabrication processing, which leads to low bulk lifetime τbulk. In order to clarify the influence of bulk lifetime on cell characteristics, two-dimensional（2D） TCAD simulation, combined with our experimental data, is used to simulate the cell performances, with the wafer thickness scaled down under various τbulk conditions. The modeling results show that for the IBC solar cell with high τbulk,（such as 1 ms-2 ms）, its open-circuit voltage V oc almost remains unchanged, and the short-circuit current density J sc monotonically decreases as the wafer thickness scales down. In comparison, for the solar cell with low τbulk（for instance, 〈 500 μs） wafer or the wafer contaminated during device processing, the V oc increases monotonically but the J sc first increases to a maximum value and then drops off as the wafer＇s thickness decreases. A model combing the light absorption and the minority carrier diffusion is used to explain this phenomenon. The research results show that for the wafer with thinner thickness and high bulk lifetime, the good light trapping technology must be developed to offset the decrease in J sc.
基金Supported by the National Natural Science Foundation of China under Grant No 10134020.
文摘We investigate the focusing phenomena of a surface acoustic wave （SAW） field generated by a circular-arc interdigital transducer （IDT） on a piezoelectric crystal. A rigorous vector field theory of surface excitation on the crystal we developed previously is used to evaluate the convergent SAW field instead of the prevalent scalar angular spectrum used in optics. The theoretical results show that the anisotropy of a medium has great impact on the focusing properties of the acoustic beams, such as focal length and symmetrical distributions near the focus. A dark field method is used in experiment to observe the focusing of the SAW tield optically. Although the convergent phenomena of SAW field on the anisotropic media or piezoelectric crystals are very complicated, the experimental data are in agreement with those from the rigorous theory.
文摘In this paper,pure polyaniline (PAN:Emeraldine base (EB) form) films and the mixed LB films of PAN and acetic acid (AA) with various layers were prepared by Langmuir-Blodgett (LB) technique.PAN based gas sensors were fabricated by deposited PAN based LB thin films on the interdigitated electrodes.The gas-sensitivity to NO_2 of PAN based gas sensors with different layers was studied.It is found that pure polyaniline LB films present higher sensitivity,responsivity and reversibility to NO_2 gas compared with polyaniline and acetic acid mixed LB films.The response time of 3-layer and 15-layer pure polyaniline LB films to 20μg/g NO_2 gas is about 10 s and 30 s,respectively.The recovery time of the 15-layer pure polyaniline LB films is close to 5 min.
文摘The Cl2-sensitive heteropolysiloxanes(HPS) film was formed on the interdigital capacitor based on silicon dioxide by means of sol-gel process and spin-on technique.Measurements of interdigital capacitance were performed at room temperature for frequencies 100 Hz,1 kHz and 10 kHz.It is shown that there is a linear relationship between the capacitance and the concentration of chlorine gas.Influences of the measurement frequency and film thickness of silicate on the sensitivity of the sensor to C12 gas were discussed.And organically modified N,N-diethylaminopropyl-trimethoxysilane (APMS) had a much higher sensitivity.
文摘With the principles of microwave circuits and semiconductor device physics,three kinds of microwave power device test circuits are designed and simulated,whose properties are evaluated by a parameter network analyzer within the frequency range from 3 to 8GHz.The simulated results verify that the test circuit with stepped-impedance filter bias network has a larger bandwidth than that with the radial stub.A microstrip interdigital capacitor is used in the third test circuit to replace the DC block,however,which does not show its advantage during the test frequency band.Based on the simulated results,the stepped-impedance filter test circuit can be used to evaluate microwave power devices in the whole C band,namely from 4 to 8GHz.
基金The authors are grateful for the support provided by the National Natural Science Foundation of China(Grant No.11772245).
文摘The electro-mechanical coupling behaviors of ferroelectric devices with interdigital electrodes may become complicated due to the material inhomogeneity and local field concentration under the complex working conditions.In this paper,a ferroelectric model,drawn from the typical interdigital electrode structure of a ferroelectric sensor,is established based on phase field theory,to study the polarization evolution and explore the evolution laws in ferroelectrics.Numerical results show that there appears ferroelectric creep even under an applied electric field below the coercive field value.Also,the configurational force theory is introduced to investigate the mechanical behaviors related to polarization switching in the ferroelectric samples with interdigital electrodes.It is found that configurational force and polarization have similar evolution laws in both time evolving and space distribution.And considering the configurational force as the driving force,it is possible to predict the potential direction of polarization evolution and explore its evolution mechanism in ferroelectrics,demonstrating the configurational force as a useful parameter for describing mechanical behavior during the polarization evolution and a powerful tool for investigating the evolution mechanism of microstructure with coupling effects in ferroelectric materials.
基金supported by the National Key Research and Development Program of China(Grant No.2016YFA02005003)the National Natural Science Foundation of China(Grant Nos.61376096 and 61327813)
文摘High-density horizontal InAs nanowire transistors are fabricated on the interdigital silicon-on-insulator substrate.Hexagonal InAs nanowires are uniformly grown between face-to-face（111） vertical sidewalls of neighboring Si fingers by metal–organic chemical vapor deposition. The density of InAs nanowires is high up to 32 per group of silicon fingers,namely an average of 4 nanowires per micrometer. The electrical characteristics with a higher on/off current ratio of 2×10~5are obtained at room temperature. The silicon-based horizontal InAs nanowire transistors are very promising for future high-performance circuits.
基金financial support from the National Natural Science Foundation of China(NSFC)(22109009)the China Postdoctoral Science Foundation(2020M680376)+2 种基金the National Key R&D Program of China(2017YFB1104300)the NSFC(21975027,22035005,52073159)the NSFC-STINT(21911530143)。
文摘Currently,the increasing demands for portable,implantable,and wearable electronics have triggered the interest in miniaturized energy storage devices.Different from conventional energy storage devices,interdigital microbatteries(IMBs) are free of separators and prepared on a single substrate,potentially achieving a short ionic diffusion path and better performance.Meanwhile,they can be easily fabricated and integrated into on-chip miniaturized electronics,holding the promise to provide long-lasting power for advanced microelectronic devices.To date,while many seminal works have been reviewed the topic of microbatteries,there is no work that systematically summarizes the development of IMBs of high energy density and stable voltage platforms from fabrication,functionalization to integration.The current review focuses on the most recent progress in IMBs,discussing advanced micromachining techniques with compatible features to construct high-performance IMBs with smart functions and intelligent integrated systems.The future opportunities and challenges of IMBs are also highlighted,calling for more efforts in this dynamic and fast-growing research field.
基金Project supported by the National Natural Science Foundation of China(No.52075484)the Zhejiang Provincial Funds for Distinguished Young Scientists of China(No.LR19E050001)the Fund for Creative Research Groups of National Natural Science Foundation of China(No.51821093)。
文摘Polymer-based materials with patterned functional particles have been used to develop smart devices with multiple functionalities.This paper presents a novel method to pattern microscale particles into biocompatible polyethylene glycol diacrylate(PEGDA)fluid through a designed surface acoustic wave(SAW)device with slanted-finger interdigital transducers(SFITs).By applying signals of different frequencies,the SFITs can excite SAWs with various wavelengths to pattern the microscale particles.The structural design and working principle of the SAW device with SFITs are firstly presented.To investigate the generation of standing SAWs and pressure field distributions of the SAW device with SFITs,a numerical model was developed.Simulation results showed that different strip-shape patterned pressure fields can be generated,and the period and width of adjacent strips can be adjusted by changing the frequencies of the excitation signals.Experiments were performed to verify that the microscale particles in the PEGDA solution can be successfully patterned into strip-shape patterns with various positions,periods,and widths.The results obtained in this study demonstrate that the developed method of using an SAW device with SFITs can be used for tunable patterning of microscale particles in solutions,and shows great potential for biomedical and microfluidic applications.
