The paper presents the design and implementation of LVDS (low-voltage differential signaling) receiver circuit, fully compatible with LVDS standard. The proposed circuit is composed of the telescopic amplifier and t...The paper presents the design and implementation of LVDS (low-voltage differential signaling) receiver circuit, fully compatible with LVDS standard. The proposed circuit is composed of the telescopic amplifier and the comparator with internal hysteresis. The receiver supports 3.5 Gbps data rate with 7.4 mA current at 1.8 V supply according to post-layout circuit simulations. The circuit has the power consumption of 13.1 MW. Comparing with the conventional circuit, the circuit is achieved to reduce the power consumption by 19.1% and the data rate by 14.3 %. The validity and effectiveness of the proposed circuit are verified through the circuit simulation with Samsung 0.18 μm CMOS (complementary metal-oxide-semiconductor) standard technology under the 1.8 V supply voltage.展开更多
Cold-junction compensation(CJC)and disconnection detection circuit design of various thermocouples(TC)and multi-channel TC interface circuits were designed.The CJC and disconnection detection circuit consists of a CJC...Cold-junction compensation(CJC)and disconnection detection circuit design of various thermocouples(TC)and multi-channel TC interface circuits were designed.The CJC and disconnection detection circuit consists of a CJC semiconductor device,an instrumentation amplifier(IA),two resistors,and a diode for disconnection detection.Based on the basic circuit,a multi-channel interface circuit was also implemented.The CJC was implemented using compensation semiconductor and IA,and disconnection detection was detected by using two resistors and a diode so that IA input voltage became-0.42 V.As a result of the experiment using R-type TC,the error of the designed circuit was reduced from 0.14 mV to 3μV after CJC in the temperature range of 0°C to 1400°C.In addition,it was confirmed that the output voltage of IA was saturated from 88 mV to-14.2 V when TC was disconnected from normal.The output voltage of the designed circuit was 0 V to 10 V in the temperature range of 0°C to 1400°C.The results of the 4-channel interface experiment using R-type TC were almost identical to the CJC and disconnection detection results for each channel.The implemented multi-channel interface has a feature that can be applied equally to E,J,K,T,R,and S-type TCs by changing the terminals of CJC semiconductor devices and adjusting the IA gain.展开更多
Efficient bifunctional catalysts for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)are vital for rechargeable Zn-air batteries(ZABs).Herein,an oxygen-respirable sponge-like Co@C–O–Cs catalyst with ...Efficient bifunctional catalysts for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)are vital for rechargeable Zn-air batteries(ZABs).Herein,an oxygen-respirable sponge-like Co@C–O–Cs catalyst with oxygen-rich active sites was designed and constructed for both ORR and OER by a facile carbon dot-assisted strategy.The aerophilic triphase interface of Co@C–O–Cs cathode efficiently boosts oxygen diffusion and transfer.The theoretical calculations and experimental studies revealed that the Co–C–COC active sites can redistribute the local charge density and lower the reaction energy barrier.The Co@C–O–Cs catalyst displays superior bifunctional catalytic activities with a half-wave potential of 0.82 V for ORR and an ultralow overpotential of 294 mV at 10 mA cm^(−2) for OER.Moreover,it can drive the liquid ZABs with high peak power density(106.4 mW cm^(−2)),specific capacity(720.7 mAh g^(−1)),outstanding long-term cycle stability(over 750 cycles at 10 mA cm^(−2)),and exhibits excellent feasibility in flexible all-solid-state ZABs.These findings provide new insights into the rational design of efficient bifunctional oxygen catalysts in rechargeable metal-air batteries.展开更多
Piezoelectric energy harvesting is considered as an ideal power resource for low-power consumption gadgets in vibrational environments.The energy extraction efficiency depends highly on the interface circuit,and shoul...Piezoelectric energy harvesting is considered as an ideal power resource for low-power consumption gadgets in vibrational environments.The energy extraction efficiency depends highly on the interface circuit,and should be highly improved to meet the power requirements.The nonlinear interface circuits in discrete components have been extensively explored and developed with the advantages of easy implementation,stable operation,high efficiency,and low cost.This paper reviews the state-of-the-art progress of nonlinear piezoelectric energy harvesting interface circuits in discrete components.First,the working principles and the advantages/disadvantages of four classical interface circuits are described.Then,the improved circuits based on the four typical circuits and other types of circuits are introduced in detail,and the advantages/disadvantages,output power,efficiency,energy consumption,and practicability of these circuits are analyzed.Finally,the future development trends of nonlinear piezoelectric energy harvesting circuits,e.g.,self-powered extraction,low-power consumption,and broadband characteristic,are predicted.展开更多
One of today's challenges is the integration of ISFETs in chemical and biochemical Microsystems.This article presents a full integration of ISFET chip containing the ISFET/REFET(reference FET) pair,ISFET/REFET amp...One of today's challenges is the integration of ISFETs in chemical and biochemical Microsystems.This article presents a full integration of ISFET chip containing the ISFET/REFET(reference FET) pair,ISFET/REFET amplifiers,bias current generator,as well as a reference electrode structure,all integrated on the same chip based on CMOS technology.The sensor chip was fabricated in a standard 0.35μm CMOS process(Chartered Semiconductor,Singapore).The extra post processing steps have been developed and added for depositing membranes.Finally,the pH response of the integrated sensor was measured with the interface circuit.展开更多
In this paper, two new electronically tunable filter configurations are proposed. The proposed filters operate current-mode (CM), voltage-mode (VM), transimpedance-mode (TIM) and transadmittance-mode (TAM). The first ...In this paper, two new electronically tunable filter configurations are proposed. The proposed filters operate current-mode (CM), voltage-mode (VM), transimpedance-mode (TIM) and transadmittance-mode (TAM). The first configuration realizes second-order VM band-pass and TAM high-pass filter characteristics from the same configuration. The second one realizes second-order TIM band-pass and CM low-pass filter characteristics from the same configuration. They also use minimum number of electronic components (two capacitors and one active component namely;current controlled current difference transconductance amplifier). The workability of the proposed structures has been demonstrated by simulation results.展开更多
Ammonia borane(AB)is an excellent candidate for the chemical storage of hydrogen.However,its practical utilization for hydrogen production is hindered by the need for expensive noble-metal-based catalysts.Herein,we re...Ammonia borane(AB)is an excellent candidate for the chemical storage of hydrogen.However,its practical utilization for hydrogen production is hindered by the need for expensive noble-metal-based catalysts.Herein,we report Co-Co3O4 nanoparticles(NPs)facilely deposited on carbon dots(CDs)as a highly efficient,robust,and noble-metal-free catalyst for the hydrolysis of AB.The incorporation of the multiinterfaces between Co,Co3O4 NPs,and CDs endows this hybrid material with excellent catalytic activity(rB=6816 mLH2 min^-1 gCo^-1)exceeding that of previous non-noble-metal NP systems and even that of some noble-metal NP systems.A further mechanistic study suggests that these interfacial interactions can affect the electronic structures of interfacial atoms and provide abundant adsorption sites for AB and water molecules,resulting in a low energy barrier for the activation of reactive molecules and thus substantial improvement of the catalytic rate.展开更多
Non-invasive cerebral neuromodulation technologies are essential for the reorganization of cerebral neural networks,which have been widely applied in the field of central neurological diseases,such as stroke,Parkinson...Non-invasive cerebral neuromodulation technologies are essential for the reorganization of cerebral neural networks,which have been widely applied in the field of central neurological diseases,such as stroke,Parkinson’s disease,and mental disorders.Although significant advances have been made in neuromodulation technologies,the identification of optimal neurostimulation paramete rs including the co rtical target,duration,and inhibition or excitation pattern is still limited due to the lack of guidance for neural circuits.Moreove r,the neural mechanism unde rlying neuromodulation for improved behavioral performance remains poorly understood.Recently,advancements in neuroimaging have provided insight into neuromodulation techniques.Functional near-infrared spectroscopy,as a novel non-invasive optical brain imaging method,can detect brain activity by measuring cerebral hemodynamics with the advantages of portability,high motion tole rance,and anti-electromagnetic interference.Coupling functional near-infra red spectroscopy with neuromodulation technologies offe rs an opportunity to monitor the cortical response,provide realtime feedbac k,and establish a closed-loop strategy integrating evaluation,feedbac k,and intervention for neurostimulation,which provides a theoretical basis for development of individualized precise neuro rehabilitation.We aimed to summarize the advantages of functional near-infra red spectroscopy and provide an ove rview of the current research on functional near-infrared spectroscopy in transcranial magnetic stimulation,transcranial electrical stimulation,neurofeedback,and braincomputer interfaces.Furthermore,the future perspectives and directions for the application of functional near-infrared spectroscopy in neuromodulation are summarized.In conclusion,functional near-infrared spectroscopy combined with neuromodulation may promote the optimization of central pellral reorganization to achieve better functional recovery form central nervous system diseases.展开更多
The superconducting rapid single flux quantum(RSFQ)integrated circuit is a promising solu-tion for overcoming speed and power bottlenecks in high-performance computing systems in the post-Moore era.This paper presents...The superconducting rapid single flux quantum(RSFQ)integrated circuit is a promising solu-tion for overcoming speed and power bottlenecks in high-performance computing systems in the post-Moore era.This paper presents an architecture designed to improve the speed and power limitations of high-performance computing systems using superconducting technology.Since superconducting microprocessors,which operate at cryogenic temperatures,require support from semiconductor cir-cuits,the proposed design utilizes the von Neumann architecture with a superconducting RSFQ mi-croprocessor,cryogenic semiconductor memory,a room temperature field programmable gate array(FPGA)controller,and a host computer for input/output.Additionally,the paper introduces two key circuit designs:a start/stop controllable superconducting clock generator and an asynchronous communication interface between the RSFQ and semiconductor chips used to implement the control system.Experimental results demonstrate that the proposed design is feasible and effective,provi-ding valuable insights for future superconducting computer systems.展开更多
The microstructural characteristic of 1070AI matrix composites reinforced by 0.15 祄 AI2O3 particles whose volume fraction was 40% was investigated by TEM and HREM. The results showed that the interface between the ma...The microstructural characteristic of 1070AI matrix composites reinforced by 0.15 祄 AI2O3 particles whose volume fraction was 40% was investigated by TEM and HREM. The results showed that the interface between the matrix and reinforcements was clean and bonded well, without any interfacial reaction products. There were some preferential crystallographic orientation relationships between Al matrix and AI2O3 particle because of the lattice imperfection on the surface of Al2O3 particles.展开更多
Herein,a bottom-down design is presented to successfully fabricate ZIF-derived Co3O4,grown in situ on a one-dimensional(1D)α-MnO2 material,denoted as α-MnO2@Co3O4.The synergistic effect derived from the coupled inte...Herein,a bottom-down design is presented to successfully fabricate ZIF-derived Co3O4,grown in situ on a one-dimensional(1D)α-MnO2 material,denoted as α-MnO2@Co3O4.The synergistic effect derived from the coupled interface constructed betweenα-MnO2 and Co3O4 is responsible for the enhanced catalytic activity.The resultantα-MnO2@Co3O4 catalyst exhibits excellent catalytic activity at a T90%(temperature required to achieve a toluene conversion of 90%)of approximately 229℃,which is 47 and 28℃ lower than those of the pureα-MnO2 nanowire and Co3O4-b obtained via pyrolysis of ZIF-67,respectively.This activity is attributed to the increase in the number of surface-adsorbed oxygen species,which accelerate the oxygen mobility and enhance the redox pairs of Mn^4+/Mn^3+ and Co^2+/Co^3+.Moreover,the result of in situ diffuse reflectance infrared Fourier transform spectroscopy suggests that the gaseous oxygen could be more easily activated to adsorbed oxygen species on the surface of α-MnO2@Co3O4 than on that of α-MnO2.The catalytic reaction route of toluene oxidation over theα-MnO2@Co3O4 catalyst is as follows:toluene→benzoate species→alkanes containing oxygen functional group→CO2 and H2O.In addition,the α-MnO2@Co3O4 catalyst shows excellent stability and good water resistance for toluene oxidation.Furthermore,the preparation method can be extended to other 1D MnO2 materials.A new strategy for the development of high-performance catalysts of practical significance is provided.展开更多
This paper presents a two-agent framework to build a natural langua g e query interface for IC information system, focusing more on scope queries in a single English sentence. The first agent, parsing agent, syntact...This paper presents a two-agent framework to build a natural langua g e query interface for IC information system, focusing more on scope queries in a single English sentence. The first agent, parsing agent, syntactically p rocesses and semantically interprets natural language sentence to construct a fu zzy structured query language (SQL) statement. The second agent, defuzzif ying agent, defuzzifies the imprecise part of the fuzzy SQL statement into its e quivalent executable precise SQL statement based on fuzzy rules. The first agent can also actively ask the user some necessary questions when it manages to disa mbiguate the vague retrieval requirements. The adaptive defuzzification approach employed in the defuzzifying agent is discussed in detail. A prototype interface has been implemented to demonstrate the effectiveness.展开更多
The correlation between surface complexation at the SiO_(2)H_(2)O interface and quartz notation behavior was studied.Computer assisted calculations,using the programs SOLGASWATER,were adapted in order to con-struct di...The correlation between surface complexation at the SiO_(2)H_(2)O interface and quartz notation behavior was studied.Computer assisted calculations,using the programs SOLGASWATER,were adapted in order to con-struct distribution diagrams of surface speciation in the SiO_(2)-metal ion-H^(+) system in aqueous solutions.Equilib-rium constants for both surface and solution reactions were introduced in the composition matrix.Surface complexation,surface charge as well as notation results were compared and a good agreement was obtained.Furthermore,flotation mechanisms of quartz activation by common metal ions like Ca^(2+),Mg^(2+),Fe^(2+) are quantitatively discussed based on the surface reaction equilibrium constants.展开更多
The theory of differential current switches which applies to the design of multivaluedECL circuits is introduced.In this theory,the switching state of differential transistor pairand signal in ECL circuits are describ...The theory of differential current switches which applies to the design of multivaluedECL circuits is introduced.In this theory,the switching state of differential transistor pairand signal in ECL circuits are described by switching variables and quaternary signal variables,respectively.he connection operations between the two kinds of variables are introduced todescribe the action process between switching element and signal in the circuits.Based on thistheory,two kinds of interface circuits-2-4 encoder and 4-2 decoder are designed.The computersimulation for the designed circuits by using SPICE program confirms that both circuits havecorrect logic functions,desired DO transfer characteristics and transient characteristics.Theseinterface circuits are compatible with binary circuits in the integrated process,the power supplyequipment,the logic stage and the transient characteristic.Therefore,they can be used as input-output interface of the existing binary ECL integrated circuits so as to decrease the number ofpins of a chip and the connections between chips.展开更多
The film forming behavior on the interface between air and hydrosol of Fe2O3 nanoparticles was investigated by the surface pressure-time isotherms, the surface pressure-trough area isotherms, Brewster angle microscopy...The film forming behavior on the interface between air and hydrosol of Fe2O3 nanoparticles was investigated by the surface pressure-time isotherms, the surface pressure-trough area isotherms, Brewster angle microscopy and transmission electron microscopy. It is found that the freshly prepared hydrosol of Fe2O3 nanoparticles is not stable. The surface pressure increases with the aging time and finally approaches a constant, and the smaller the concentration is, the smaller the surface pressure is stabilized at and the shorter the time the hydrosol reaching stable needs. The surface pressure also increases with compression until collapsed, and the longer the hydrosol is aged, the higher the collapsing pressure is. A uniform and compact film composed of nanoparticles with an average diameter of about 2-3 nm on the air-hydrosol interface is observed by Brewster angle microscope and transmission electron microscope.展开更多
Frequency dependent conductance measurements are implemented to investigate the interface states in Al2O3/A1GaN/GaN metal-oxide-semiconductor (MOS) structures. Two types of device structures, namely, the recessed ga...Frequency dependent conductance measurements are implemented to investigate the interface states in Al2O3/A1GaN/GaN metal-oxide-semiconductor (MOS) structures. Two types of device structures, namely, the recessed gate structure (RGS) and the normal gate structure (NGS), are studied in the experiment. Interface trap parameters includ-ing trap density Dit, trap time constant ιit, and trap state energy ET in both devices have been determined. Furthermore, the obtained results demonstrate that the gate recess process can induce extra traps with shallower energy levels at the Al2O3/AlGaN interface due to the damage on the surface of the AlGaN barrier layer resulting from reactive ion etching (RIE).展开更多
The distributions of traps and electron density in the interfaces between polyimide (PI) matrix and Al2O3 nanoparticles are researched using the isothermal decay current and the small-angle x-ray scattering (SAXS)...The distributions of traps and electron density in the interfaces between polyimide (PI) matrix and Al2O3 nanoparticles are researched using the isothermal decay current and the small-angle x-ray scattering (SAXS) tests. According to the electron density distribution for quasi two-phase mixture doped by spherical nanoparticles, the electron densities in the interfaces of PI/Al2O3 nanocomposite films are evaluated. The trap level density and carrier mobility in the interface are studied. The experimental results show that the distribution and the change rate of the electron density in the three layers of interface are different, indicating different trap distributions in the interface layers. There is a maximum trap level density in the second layer, where the maximum trap level density for the nanocomposite film doped by 25 wt% is 1.054 × 10^22 eV·m^-3 at 1.324eV, resulting in the carrier mobility reducing. In addition, both the thickness and the electron density of the nanocomposite film interface increase with the addition of the doped Al2O3 contents. Through the study on the trap level distribution in the interface, it is possible to further analyze the insulation mechanism and to improve the performance of nano-dielectric materials.展开更多
文摘The paper presents the design and implementation of LVDS (low-voltage differential signaling) receiver circuit, fully compatible with LVDS standard. The proposed circuit is composed of the telescopic amplifier and the comparator with internal hysteresis. The receiver supports 3.5 Gbps data rate with 7.4 mA current at 1.8 V supply according to post-layout circuit simulations. The circuit has the power consumption of 13.1 MW. Comparing with the conventional circuit, the circuit is achieved to reduce the power consumption by 19.1% and the data rate by 14.3 %. The validity and effectiveness of the proposed circuit are verified through the circuit simulation with Samsung 0.18 μm CMOS (complementary metal-oxide-semiconductor) standard technology under the 1.8 V supply voltage.
文摘Cold-junction compensation(CJC)and disconnection detection circuit design of various thermocouples(TC)and multi-channel TC interface circuits were designed.The CJC and disconnection detection circuit consists of a CJC semiconductor device,an instrumentation amplifier(IA),two resistors,and a diode for disconnection detection.Based on the basic circuit,a multi-channel interface circuit was also implemented.The CJC was implemented using compensation semiconductor and IA,and disconnection detection was detected by using two resistors and a diode so that IA input voltage became-0.42 V.As a result of the experiment using R-type TC,the error of the designed circuit was reduced from 0.14 mV to 3μV after CJC in the temperature range of 0°C to 1400°C.In addition,it was confirmed that the output voltage of IA was saturated from 88 mV to-14.2 V when TC was disconnected from normal.The output voltage of the designed circuit was 0 V to 10 V in the temperature range of 0°C to 1400°C.The results of the 4-channel interface experiment using R-type TC were almost identical to the CJC and disconnection detection results for each channel.The implemented multi-channel interface has a feature that can be applied equally to E,J,K,T,R,and S-type TCs by changing the terminals of CJC semiconductor devices and adjusting the IA gain.
基金supported by the National Key Research and Development Program of China(No.2019YFC1907801)National Natural Science Foundation of China(No.52174286)+1 种基金the Science and Technology Innovation Program of Hunan Province(2021RC3014)Innovation-Driven Project of Central South University(No.2020CX007)。
文摘Efficient bifunctional catalysts for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)are vital for rechargeable Zn-air batteries(ZABs).Herein,an oxygen-respirable sponge-like Co@C–O–Cs catalyst with oxygen-rich active sites was designed and constructed for both ORR and OER by a facile carbon dot-assisted strategy.The aerophilic triphase interface of Co@C–O–Cs cathode efficiently boosts oxygen diffusion and transfer.The theoretical calculations and experimental studies revealed that the Co–C–COC active sites can redistribute the local charge density and lower the reaction energy barrier.The Co@C–O–Cs catalyst displays superior bifunctional catalytic activities with a half-wave potential of 0.82 V for ORR and an ultralow overpotential of 294 mV at 10 mA cm^(−2) for OER.Moreover,it can drive the liquid ZABs with high peak power density(106.4 mW cm^(−2)),specific capacity(720.7 mAh g^(−1)),outstanding long-term cycle stability(over 750 cycles at 10 mA cm^(−2)),and exhibits excellent feasibility in flexible all-solid-state ZABs.These findings provide new insights into the rational design of efficient bifunctional oxygen catalysts in rechargeable metal-air batteries.
基金the National Natural Science Foundation of China(Nos.51805298 and 12072267)the Natural Science Foundation of Shandong Province of China(No.ZR2019PEE015)+3 种基金the Fundamental Research Funds for the Central Universities of China(No.2019ZRJC006)the 111 Project of China(No.BP0719007)the Innovation Capability Support Plan of Shaanxi Province of China(No.2020KJXX-021)the Young Scholars Program of Shandong University,Weihai of China(No.20820201004)。
文摘Piezoelectric energy harvesting is considered as an ideal power resource for low-power consumption gadgets in vibrational environments.The energy extraction efficiency depends highly on the interface circuit,and should be highly improved to meet the power requirements.The nonlinear interface circuits in discrete components have been extensively explored and developed with the advantages of easy implementation,stable operation,high efficiency,and low cost.This paper reviews the state-of-the-art progress of nonlinear piezoelectric energy harvesting interface circuits in discrete components.First,the working principles and the advantages/disadvantages of four classical interface circuits are described.Then,the improved circuits based on the four typical circuits and other types of circuits are introduced in detail,and the advantages/disadvantages,output power,efficiency,energy consumption,and practicability of these circuits are analyzed.Finally,the future development trends of nonlinear piezoelectric energy harvesting circuits,e.g.,self-powered extraction,low-power consumption,and broadband characteristic,are predicted.
基金supported by National Natural Science Foundation of China(No.90307014)
文摘One of today's challenges is the integration of ISFETs in chemical and biochemical Microsystems.This article presents a full integration of ISFET chip containing the ISFET/REFET(reference FET) pair,ISFET/REFET amplifiers,bias current generator,as well as a reference electrode structure,all integrated on the same chip based on CMOS technology.The sensor chip was fabricated in a standard 0.35μm CMOS process(Chartered Semiconductor,Singapore).The extra post processing steps have been developed and added for depositing membranes.Finally,the pH response of the integrated sensor was measured with the interface circuit.
文摘In this paper, two new electronically tunable filter configurations are proposed. The proposed filters operate current-mode (CM), voltage-mode (VM), transimpedance-mode (TIM) and transadmittance-mode (TAM). The first configuration realizes second-order VM band-pass and TAM high-pass filter characteristics from the same configuration. The second one realizes second-order TIM band-pass and CM low-pass filter characteristics from the same configuration. They also use minimum number of electronic components (two capacitors and one active component namely;current controlled current difference transconductance amplifier). The workability of the proposed structures has been demonstrated by simulation results.
基金financially supported by the National Natural Science Foundation of China(21774041 and 51433003)the China Postdoctoral Science Foundation(2018M640681 and 2019T120632)。
文摘Ammonia borane(AB)is an excellent candidate for the chemical storage of hydrogen.However,its practical utilization for hydrogen production is hindered by the need for expensive noble-metal-based catalysts.Herein,we report Co-Co3O4 nanoparticles(NPs)facilely deposited on carbon dots(CDs)as a highly efficient,robust,and noble-metal-free catalyst for the hydrolysis of AB.The incorporation of the multiinterfaces between Co,Co3O4 NPs,and CDs endows this hybrid material with excellent catalytic activity(rB=6816 mLH2 min^-1 gCo^-1)exceeding that of previous non-noble-metal NP systems and even that of some noble-metal NP systems.A further mechanistic study suggests that these interfacial interactions can affect the electronic structures of interfacial atoms and provide abundant adsorption sites for AB and water molecules,resulting in a low energy barrier for the activation of reactive molecules and thus substantial improvement of the catalytic rate.
文摘Non-invasive cerebral neuromodulation technologies are essential for the reorganization of cerebral neural networks,which have been widely applied in the field of central neurological diseases,such as stroke,Parkinson’s disease,and mental disorders.Although significant advances have been made in neuromodulation technologies,the identification of optimal neurostimulation paramete rs including the co rtical target,duration,and inhibition or excitation pattern is still limited due to the lack of guidance for neural circuits.Moreove r,the neural mechanism unde rlying neuromodulation for improved behavioral performance remains poorly understood.Recently,advancements in neuroimaging have provided insight into neuromodulation techniques.Functional near-infrared spectroscopy,as a novel non-invasive optical brain imaging method,can detect brain activity by measuring cerebral hemodynamics with the advantages of portability,high motion tole rance,and anti-electromagnetic interference.Coupling functional near-infra red spectroscopy with neuromodulation technologies offe rs an opportunity to monitor the cortical response,provide realtime feedbac k,and establish a closed-loop strategy integrating evaluation,feedbac k,and intervention for neurostimulation,which provides a theoretical basis for development of individualized precise neuro rehabilitation.We aimed to summarize the advantages of functional near-infra red spectroscopy and provide an ove rview of the current research on functional near-infrared spectroscopy in transcranial magnetic stimulation,transcranial electrical stimulation,neurofeedback,and braincomputer interfaces.Furthermore,the future perspectives and directions for the application of functional near-infrared spectroscopy in neuromodulation are summarized.In conclusion,functional near-infrared spectroscopy combined with neuromodulation may promote the optimization of central pellral reorganization to achieve better functional recovery form central nervous system diseases.
基金the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDA18000000)the National Natural Science Foundation of China(No.61732018,61872335).
文摘The superconducting rapid single flux quantum(RSFQ)integrated circuit is a promising solu-tion for overcoming speed and power bottlenecks in high-performance computing systems in the post-Moore era.This paper presents an architecture designed to improve the speed and power limitations of high-performance computing systems using superconducting technology.Since superconducting microprocessors,which operate at cryogenic temperatures,require support from semiconductor cir-cuits,the proposed design utilizes the von Neumann architecture with a superconducting RSFQ mi-croprocessor,cryogenic semiconductor memory,a room temperature field programmable gate array(FPGA)controller,and a host computer for input/output.Additionally,the paper introduces two key circuit designs:a start/stop controllable superconducting clock generator and an asynchronous communication interface between the RSFQ and semiconductor chips used to implement the control system.Experimental results demonstrate that the proposed design is feasible and effective,provi-ding valuable insights for future superconducting computer systems.
基金This research is supported by the National Natural Science Foundation of China (under Grant No.59771014 and No.50071019). The help of the National Advanced Material Open Research Lab of Tsinghua University is gratefully acknowledged.
文摘The microstructural characteristic of 1070AI matrix composites reinforced by 0.15 祄 AI2O3 particles whose volume fraction was 40% was investigated by TEM and HREM. The results showed that the interface between the matrix and reinforcements was clean and bonded well, without any interfacial reaction products. There were some preferential crystallographic orientation relationships between Al matrix and AI2O3 particle because of the lattice imperfection on the surface of Al2O3 particles.
文摘Herein,a bottom-down design is presented to successfully fabricate ZIF-derived Co3O4,grown in situ on a one-dimensional(1D)α-MnO2 material,denoted as α-MnO2@Co3O4.The synergistic effect derived from the coupled interface constructed betweenα-MnO2 and Co3O4 is responsible for the enhanced catalytic activity.The resultantα-MnO2@Co3O4 catalyst exhibits excellent catalytic activity at a T90%(temperature required to achieve a toluene conversion of 90%)of approximately 229℃,which is 47 and 28℃ lower than those of the pureα-MnO2 nanowire and Co3O4-b obtained via pyrolysis of ZIF-67,respectively.This activity is attributed to the increase in the number of surface-adsorbed oxygen species,which accelerate the oxygen mobility and enhance the redox pairs of Mn^4+/Mn^3+ and Co^2+/Co^3+.Moreover,the result of in situ diffuse reflectance infrared Fourier transform spectroscopy suggests that the gaseous oxygen could be more easily activated to adsorbed oxygen species on the surface of α-MnO2@Co3O4 than on that of α-MnO2.The catalytic reaction route of toluene oxidation over theα-MnO2@Co3O4 catalyst is as follows:toluene→benzoate species→alkanes containing oxygen functional group→CO2 and H2O.In addition,the α-MnO2@Co3O4 catalyst shows excellent stability and good water resistance for toluene oxidation.Furthermore,the preparation method can be extended to other 1D MnO2 materials.A new strategy for the development of high-performance catalysts of practical significance is provided.
文摘This paper presents a two-agent framework to build a natural langua g e query interface for IC information system, focusing more on scope queries in a single English sentence. The first agent, parsing agent, syntactically p rocesses and semantically interprets natural language sentence to construct a fu zzy structured query language (SQL) statement. The second agent, defuzzif ying agent, defuzzifies the imprecise part of the fuzzy SQL statement into its e quivalent executable precise SQL statement based on fuzzy rules. The first agent can also actively ask the user some necessary questions when it manages to disa mbiguate the vague retrieval requirements. The adaptive defuzzification approach employed in the defuzzifying agent is discussed in detail. A prototype interface has been implemented to demonstrate the effectiveness.
文摘The correlation between surface complexation at the SiO_(2)H_(2)O interface and quartz notation behavior was studied.Computer assisted calculations,using the programs SOLGASWATER,were adapted in order to con-struct distribution diagrams of surface speciation in the SiO_(2)-metal ion-H^(+) system in aqueous solutions.Equilib-rium constants for both surface and solution reactions were introduced in the composition matrix.Surface complexation,surface charge as well as notation results were compared and a good agreement was obtained.Furthermore,flotation mechanisms of quartz activation by common metal ions like Ca^(2+),Mg^(2+),Fe^(2+) are quantitatively discussed based on the surface reaction equilibrium constants.
基金The project is supported by Zhejiang Provincial Natural Science Fund of China
文摘The theory of differential current switches which applies to the design of multivaluedECL circuits is introduced.In this theory,the switching state of differential transistor pairand signal in ECL circuits are described by switching variables and quaternary signal variables,respectively.he connection operations between the two kinds of variables are introduced todescribe the action process between switching element and signal in the circuits.Based on thistheory,two kinds of interface circuits-2-4 encoder and 4-2 decoder are designed.The computersimulation for the designed circuits by using SPICE program confirms that both circuits havecorrect logic functions,desired DO transfer characteristics and transient characteristics.Theseinterface circuits are compatible with binary circuits in the integrated process,the power supplyequipment,the logic stage and the transient characteristic.Therefore,they can be used as input-output interface of the existing binary ECL integrated circuits so as to decrease the number ofpins of a chip and the connections between chips.
基金Funded by the National Natural Science Foundation of China (50672089)the Encouraging Foundation for the Scientific Research of the Excellent Young and Middleaged Scientists in Shandong Province(2006BS04034)
文摘The film forming behavior on the interface between air and hydrosol of Fe2O3 nanoparticles was investigated by the surface pressure-time isotherms, the surface pressure-trough area isotherms, Brewster angle microscopy and transmission electron microscopy. It is found that the freshly prepared hydrosol of Fe2O3 nanoparticles is not stable. The surface pressure increases with the aging time and finally approaches a constant, and the smaller the concentration is, the smaller the surface pressure is stabilized at and the shorter the time the hydrosol reaching stable needs. The surface pressure also increases with compression until collapsed, and the longer the hydrosol is aged, the higher the collapsing pressure is. A uniform and compact film composed of nanoparticles with an average diameter of about 2-3 nm on the air-hydrosol interface is observed by Brewster angle microscope and transmission electron microscope.
基金Project supported by the National Basic Research Program of China(Grant No.2011CBA00606)
文摘Frequency dependent conductance measurements are implemented to investigate the interface states in Al2O3/A1GaN/GaN metal-oxide-semiconductor (MOS) structures. Two types of device structures, namely, the recessed gate structure (RGS) and the normal gate structure (NGS), are studied in the experiment. Interface trap parameters includ-ing trap density Dit, trap time constant ιit, and trap state energy ET in both devices have been determined. Furthermore, the obtained results demonstrate that the gate recess process can induce extra traps with shallower energy levels at the Al2O3/AlGaN interface due to the damage on the surface of the AlGaN barrier layer resulting from reactive ion etching (RIE).
基金Supported by the National Natural Science Foundation of China under Grant Nos 51337002,51077028,51502063 and 51307046the Foundation of Harbin Science and Technology Bureau of Heilongjiang Province under Grant No RC2014QN017034
文摘The distributions of traps and electron density in the interfaces between polyimide (PI) matrix and Al2O3 nanoparticles are researched using the isothermal decay current and the small-angle x-ray scattering (SAXS) tests. According to the electron density distribution for quasi two-phase mixture doped by spherical nanoparticles, the electron densities in the interfaces of PI/Al2O3 nanocomposite films are evaluated. The trap level density and carrier mobility in the interface are studied. The experimental results show that the distribution and the change rate of the electron density in the three layers of interface are different, indicating different trap distributions in the interface layers. There is a maximum trap level density in the second layer, where the maximum trap level density for the nanocomposite film doped by 25 wt% is 1.054 × 10^22 eV·m^-3 at 1.324eV, resulting in the carrier mobility reducing. In addition, both the thickness and the electron density of the nanocomposite film interface increase with the addition of the doped Al2O3 contents. Through the study on the trap level distribution in the interface, it is possible to further analyze the insulation mechanism and to improve the performance of nano-dielectric materials.