Membrane separation technology with the ability to regulate gas/liquid transport and separation is critical for environmental fields, such as sewerage treatment, multiphase separation, and desalination. Although numer...Membrane separation technology with the ability to regulate gas/liquid transport and separation is critical for environmental fields, such as sewerage treatment, multiphase separation, and desalination. Although numerous membranes can dynamically control liquid-phase fluids transport via external stimuli, the transport and separation of gas-phase fluids remains a challenge. Here, we show a temperature-regulation liquid gating membrane that allows in-situ dynamically controllable gas/liquid transfer and multiphase separation by integrating a thermo-wettability responsive porous membrane with functional gating liquid. Experiments and theoretical analysis have demonstrated the temperature-regulation mechanism of this liquid gating system, which is based on thermo-responsive changes of porous membrane surface polarity, leading to changes in affinity between the porous membrane and the gating liquid. In addition, the sandwich configuration with dense Au-coated surfaces and heterogeneous internal components by a bistable interface design enables the liquid gating system to enhance response sensitivity and maintain working stability. This temperature-regulation gas/liquid transfer strategy expands the application range of liquid gating membranes,which are promising in environmental governance, water treatment and multiphase separation.展开更多
The self-absorption effect in laser-induced breakdown spectroscopy(LIBS)reduces the accuracy of quantitative measurement results.The self-absorption-free LIBS(SAF-LIBS)has been proved to directly capture the optically...The self-absorption effect in laser-induced breakdown spectroscopy(LIBS)reduces the accuracy of quantitative measurement results.The self-absorption-free LIBS(SAF-LIBS)has been proved to directly capture the optically thin plasma spectra by setting an appropriate exposure time.In this work,a novel SAF-LIBS technique with high repetition rate acousto-optic gating is developed,in which an acousto-optic modulator is used as the shutter to diffract the optically thin fluorescence,and a high repetition rate laser is used to produce quasi-continuous plasmas to enhance the integral spectral intensity,so that the CCD spectrometer can replace an intensified CCD(ICCD)and echelle spectrometer in SAF-LIBS.Experimental results show that the average absolute prediction error of aluminum is reduced to 0.18%,which is equivalent to that of traditional SAF-LIBS.This technique not only effectively shields continuous background radiation and broadened spectral lines in optically thick plasma,but also has advantages of miniaturization,low cost,convenience and reliability.展开更多
Cyclic nucleotide-gated ion channels (CNGs) are distributed most widely in the neuronal cell. Great progress has been made in molecular mechanisms of CNG channel gating in the recent years. Results of many experimen...Cyclic nucleotide-gated ion channels (CNGs) are distributed most widely in the neuronal cell. Great progress has been made in molecular mechanisms of CNG channel gating in the recent years. Results of many experiments have indicated that the stoichiometry and assembly of CNG channels affect their property and gating. Experiments of CNG mutants and analyses of cys- teine accessibilities show that cyclic nucleotide-binding domains (CNBD) bind cyclic nucleotides and subsequently conformational changes occurred followed by the concerted or cooperative conformational change of all four subunits during CNG gating. In order to provide theoretical assistances for further investigation on CNG channels, especially regarding the disease pathogenesis of ion channels, this paper reviews the latest progress on mechanisms of CNG channels, functions of subunits, processes of subunit assembly, and conformational changes of subunit regions during gating.展开更多
A novel clock structure of a low-power 16-bit very large instruction word (VLIW) digital signal processor (DSP) was proposed. To improve deterministic clock gating and to solve the drawback of conventional clock gatin...A novel clock structure of a low-power 16-bit very large instruction word (VLIW) digital signal processor (DSP) was proposed. To improve deterministic clock gating and to solve the drawback of conventional clock gating circuit in high speed circuit, a distributed and early clock gating method was developed on its instruction fetch & decoder unit, its pipelined data-path unit and its super-Harvard memory interface unit. The core was implemented following the Synopsys back-end flow under TSMC (Taiwan Silicon manufacture corporation) 0.18-μm 1.8-V 1P6M process, with a core size of 2 mm×2 mm. Result shows that it can run under 200 MHz with a power performance around 0.3 mW/MIPS. Meanwhile, only 39.7% circuit is active simultaneously in average, compared to its non-gating counterparts.展开更多
This work is concerned with the hydraulics and f low characterization in a pressurized,horizontal gating system with multiple ingates attached to a plate mold,using transparent water models.Runners with two different ...This work is concerned with the hydraulics and f low characterization in a pressurized,horizontal gating system with multiple ingates attached to a plate mold,using transparent water models.Runners with two different aspect ratios(w/h=0.5 and 2)and four different types of ingates(rectangular,convergent,divergent and venturi)were examined for their influence on flow behavior.Flow behavior was visualized using a high speed camera capable of capturing images up to 10,000 frames per second.Real time experimentation with a few runner–ingate combinations were carried out to validate the usefulness of water models in predicting the f illing behavior.Comparison of the approaches provided useful insights into the filling behavior in critical sections of the flow passages as well as the utility of water models towards understanding of the f illing behavior during real time casting.展开更多
High pressure die casting(HPDC) is a kind of near net shape manufacturing method. However, air entrapment in HPDC parts has serious effects upon the casting quality. In order to reduce the air entrapment defects in a ...High pressure die casting(HPDC) is a kind of near net shape manufacturing method. However, air entrapment in HPDC parts has serious effects upon the casting quality. In order to reduce the air entrapment defects in a AlSi10 MnMg alloy thin-wall longitudinal load-bearing beam produced by HPDC, different gating systems were designed and simulated by software Flow-3D to evaluate the entrapped air. Simulation results showed that when the beam is produced by the original designed gating system with a middle ingate, there exist obvious air entrapments in the critical area; the volume of air entrapment was reduced by replacing the middle ingate to an overflow well, and the filling of molten metal became more stable. When the middle ingate was removed for further improvement, the volume of air entrapment was decreased drastically. The parts with glossy surface and good microstructure have been successfully produced by using the final optimized gating system based on simulation results.展开更多
We report protonation in several compounds by an ionic-liquid-gating method, under optimized gating conditions.This leads to single superconducting phases for several compounds. Non-volatility of protons allows post-g...We report protonation in several compounds by an ionic-liquid-gating method, under optimized gating conditions.This leads to single superconducting phases for several compounds. Non-volatility of protons allows post-gating magnetization and transport measurements. The superconducting transition temperature Tc is enhanced to 43.5 K for FeSe0.93S0.07, and 41 K for Fe Se after protonation. Superconducting transitions with Tc^15 K for ZrNCl,~7.2 K for 1-TaS2, and ~3.8 K for Bi2Se3 are induced after protonation. Electric transport in protonated FeSe0.93S0.07 confirms high-temperature superconductivity. Our ^1H nuclear magnetic resonance(NMR)measurements on protonated Fe Se1-xSx reveal enhanced spin-lattice relaxation rate 1/^1T1 with increasing x,which is consistent with the LDA calculations that H+ is located in the interstitial sites close to the anions.展开更多
The gating system of a cylindrical magnesium casting has been designed by using multiple objective optimiza- tion and Taguchi method.Mold filling and solidification processes were simulated by using MAGMASOFT(?). T...The gating system of a cylindrical magnesium casting has been designed by using multiple objective optimiza- tion and Taguchi method.Mold filling and solidification processes were simulated by using MAGMASOFT(?). The simulation results indicate that the gating system design has a significant effect on the quality of magne- sium castings.In an effort to obtain the optimal design of gating system,the signal-to-noise (S/N) ratio was used to analyze the effect of various gating designs on cavity filling and casting quality by using a weighting method based on the design of an orthogonal array.Four gating system parameters,namely,ingate height, ingate width,runner height,runner width,were optimized with a consideration of multiple objective criteria including filling velocity,shrinkage porosity and product yield.展开更多
The electronic doping effect on both the superconductivity and the nematic order in the FeSe nanoflake are investigated by using the electric-double-layer transistor configuration. The superconductivity can be effecti...The electronic doping effect on both the superconductivity and the nematic order in the FeSe nanoflake are investigated by using the electric-double-layer transistor configuration. The superconductivity can be effectively controlled by electronic doping, and the onset superconducting transition temperature Tc reaches as high as 45 K at a gate voltage Of Vg = 4 V. Meanwhile, the nematic phase is gradually suppressed with the increase of electronic doping (or Vg). The results provide an effective method with variable charge doping for investigation of the rich physics in the FeSe superconductor.展开更多
Calcium-release-activated calcium(CARC)channels are one of the major pathways of calcium entry in non-excitable cells.Despite a decade or two of research,its regulatory mechanism is not yet thoroughly understood.The s...Calcium-release-activated calcium(CARC)channels are one of the major pathways of calcium entry in non-excitable cells.Despite a decade or two of research,its regulatory mechanism is not yet thoroughly understood.The slow progress is due to the complexity of its pores(i.e.,Orai)on one hand and the difficulty in capturing its regulatory complex on the other hand.As a result,possible gating mechanisms have often been speculated by exploring the structure and properties of constitutive open mutants.However,there is much debate about how they can truly reflect the gating of CRAC channels under physiological conditions.In the present study,we combined molecular dynamics simulations with free energy calculations to study three dOrai mutants(G170P,H206A,and P288A),and further calculated their current-voltage curves.Results show that these constructs adopt different approaches to maintain their conductive state.Meanwhile they have unique pore structures and distinctive rectification properties and ion selectivity for cations compared to wild-type pores.We conclude that although the mutants may partially capture the gating motion characteristics of wild-type pores,the information obtained from these mutants is likely not a true reflection of CRAC channel gating under physiological conditions.展开更多
A convolutional neural network is employed to retrieve the time-domain envelop and phase of few-cycle femtosecond pulses from transient-grating frequency-resolved optical gating(TG-FROG) traces.We use theoretically ge...A convolutional neural network is employed to retrieve the time-domain envelop and phase of few-cycle femtosecond pulses from transient-grating frequency-resolved optical gating(TG-FROG) traces.We use theoretically generated TGFROG traces to complete supervised trainings of the convolutional neural networks,then use similarly generated traces not included in the training dataset to test how well the networks are trained.Accurate retrieval of such traces by the neural network is realized.In our case,we find that networks with exponential linear unit(ELU) activation function perform better than those with leaky rectified linear unit(LRELU) and scaled exponential linear unit(SELU).Finally,the issues that need to be addressed for the retrieval of experimental data by this method are discussed.展开更多
The delegating private quantum computation(DQC)protocol with the universal quantum gate set{X,Z,H,P,R,CNOT}was firstly proposed by Broadbent et al.[Broadbent(2015)],and then Tan et al.[Tan and Zhou(2017)]tried to put ...The delegating private quantum computation(DQC)protocol with the universal quantum gate set{X,Z,H,P,R,CNOT}was firstly proposed by Broadbent et al.[Broadbent(2015)],and then Tan et al.[Tan and Zhou(2017)]tried to put forward a half-blind DQC protocol(HDQC)with another universal set{H,P,CNOT,T}.However,the decryption circuit of Toffoli gate(i.e.T)is a little redundant,and Tan et al.’s protocol[Tan and Zhou(2017)]exists the information leak.In addition,both of these two protocols just focus on the blindness of data(i.e.the client’s input and output),but do not consider the blindness of computation(i.e.the delegated quantum operation).For solving these problems,we propose a full-blind DQC protocol(FDQC)with quantum gate set{H,P,CNOT,T},where the desirable delegated quantum operation,one of{H,P,CNOT,T},is replaced by a fixed sequence(H,P,CZ,CNOT,T)to make the computation blind,and the decryption circuit of Toffoli gate is also optimized.Analysis shows that our protocol can not only correctly perform any delegated quantum computation,but also holds the characteristics of data blindness and computation blindness.展开更多
The main problems caused by improper gating are entrained aluminum oxide films and entrapped gas.In this study,the slot gating system is employed to improve mold filling behavior and therefore,to improve the quality o...The main problems caused by improper gating are entrained aluminum oxide films and entrapped gas.In this study,the slot gating system is employed to improve mold filling behavior and therefore,to improve the quality of aluminum castings produced in permanent molds.An equipment as well as operation procedures for real-time X-ray radiography of molten aluminum flowing into permanent molds have been developed.Graphite molds transparent to X-rays are utilized which make it possible to observe the flow pattern through a number of vertically oriented gating systems.The investigation discovers that there are many influencing factors on the mold filling process.This paper focuses its research on some of the factors,such as the dimensions of the vertical riser and slot thickness,as well as roughness of the coating layer.The results indicate that molten metal can smoothly fill into casting cavity with a proper slot gating system.A bigger vertical riser,proper slot thickness and rougher coating can provide not only a better mold filling pattern,but also hot melt into the top of the cavity.A proper temperature gradient is obtainable,higher at the bottom and lower at the top of the casting cavity,which is in favor of feeding during casting solidification.展开更多
In foundries a lot of effort is done to minimize energy consumption in the production to reduce costs and hence increase the competitiveness. At the same time the foundries must live up to the increased demands for hi...In foundries a lot of effort is done to minimize energy consumption in the production to reduce costs and hence increase the competitiveness. At the same time the foundries must live up to the increased demands for high quality castings. Traditional gating systems are known for a straight tapered down runner, a well base and 90° bends in the runner system. Previous work has shown that the traditional way of designing gating systems creates high inconsistency in flow patterns during filling. In the streamlined gating systems there are no sharp changes in direction and a large effort is done to confine and control the flow of the molten metal during mould filling. The main objective in the work presented here is to use the principles of the streamlined gating systems to reduce the weight of the gating system relative to the traditional layouts. By reducing the weight of gating system and thereby improving yield, the amount of molten iron needed is also reduced, hence reducing the energy consumption for melting. Experiments in real production lines have proven that it is possible to achieve a reduction in the poured weight by using the streamlined gating systems. In a layout for casting of three valve housings in a vertically parted mould the weight of the gating system was reduced by 1.1 kg changing from the traditional layouts to the streamlined gating systems. This weight reduction corresponds in this case to a 20% weight reduction for the gating system. Using streamlined gating systems with fan gates to give a beneficial heat distribution in the castings may be an efficient tool to eliminate the need for heat treatment. In the experiments the change in gating system from the traditional layout to the streamlined layout removed the need for heat treatment. This obviously means a huge energy saving in the foundry. The energy consumption for heat treatment of iron has been found to be 0.489 kWh/ kg. The valve housing in the experiments weighs 3 kg so when the need for heat treatment is removed, around 1.5 kWh is saved per casting. Along with the reduction in energy used the foundry also save the cost of handling the castings for the heat treatment and the production times is reduced considerably When the moulds for the vertical layout is produced on a DISAMATIC that produces 350 moulds an hour the total energy saved per hour for both melting and heat treatment becomes 2,000 kWh and per eight hour work day 16,000 kWh. Seen in this perspective the potential for saving energy in the foundries is substantial. Furthermore the experiments where ductile iron valve housings was cast also proved that it is possible to lower the pouring temperature from 1,400℃ to 1,300℃ without the risk of cold runs. This is possible due to a high flow rate during mould filling in combination with low velocities due to the use of fan gates. All of this has also been investigated in experiments using glass plate fronted moulds.展开更多
The carrier-density-dependent spin relaxation dynamics for modulation-doped GaAs/Al0.3 Gao,TAs quantum wells is studied using the time-resolved magneto-Kerr rotation measurements. The electron spin relaxation time and...The carrier-density-dependent spin relaxation dynamics for modulation-doped GaAs/Al0.3 Gao,TAs quantum wells is studied using the time-resolved magneto-Kerr rotation measurements. The electron spin relaxation time and its in-plane anisotropy are studied as a function of the optically injected electron density, Moreover, the relative strength of the Rashba and the Dresselhaus spin-rbit coupling fields, and thus the observed spin relaxation time anisotropy, is further tuned by the additional excitation of a 532nm continuous wave laser, demonstrating an effective spin relaxation manipulation via an optical gating method.展开更多
GHz single-photon detector (SPD) is a crucial part in the practical high speed quantum key distribution (QKD) system. However, any imperfections in a practical QKD system may be exploited by an eavesdropper (Eve...GHz single-photon detector (SPD) is a crucial part in the practical high speed quantum key distribution (QKD) system. However, any imperfections in a practical QKD system may be exploited by an eavesdropper (Eve) to collect information about the key without being discovered. The sine wave gating SPD (SG-SPD) based on InGaAs/InP avalanche photodiode, one kind of practical high speed SPD, may also contain loopholes. In this paper, we study the principle and characteristic of the SG-SPD and find out the filtering loophole of the SG-SPD for the first time. What is more, the proof-of-principle experiment shows that Eve could blind and control Bob's SG-SPD by exploiting this loophole. We believe that giving enough attention to this loophole can improve the practical security of the existing QKD system. GHz single-photon detector (SPD) is a crucial part in the practical high speed quantum key distribution (QKD) system. However, any imperfections in a practical QKD system may be exploited by an eavesdropper (Eve) to collect information about the key without being discovered. The sine wave gating SPD (SG-SPD) based on InGaAs/InP avalanche photodiode, one kind of practical high speed SPD, may also contain loopholes. In this paper, we study the principle and characteristic of the SG-SPD and find out the filtering loophole of the SG-SPD for the first time. What is more, the proof-of-principle experiment shows that Eve could blind and control Bob's SG-SPD by exploiting this loophole. We believe that giving enough attention to this loophole can improve the practical security of the existing QKD system.展开更多
The classical model of voltage-gated ion channels assumes that according to a Markov process ion channels switch among a small number of states without memory, but a bunch of experimental papers show that some ion cha...The classical model of voltage-gated ion channels assumes that according to a Markov process ion channels switch among a small number of states without memory, but a bunch of experimental papers show that some ion channels exhibit significant memory effects, and this memory effects can take the form of kinetic rate constant that is fractal. Obviously the gating character of ion channels will affect generation and propagation of action potentials, furthermore, affect generation, coding and propagation of neural information. However, there is little previous research on this series of interesting issues. This paper investigates effects of fractal gating of potassium channel subunits switching from closed state to open state on neuronal behaviours. The obtained results show that fractal gating of potassium channel subunits switching from closed state to open state has important effects on neuronal behaviours, increases excitability, rest potential and spiking frequency of the neuronal membrane, and decreases threshold voltage and threshold injected current of the neuronal membrane. So fractal gating of potassium channel subunits switching from closed state to open state can improve the sensitivity of the neuronal membrane, and enlarge the encoded strength of neural information.展开更多
We report the electrical transport properties of InSe flakes electrostatically gated by a solid ion conductor.The large tuning capability of the solid ion conductor as gating dielectric is confirmed by the saturation ...We report the electrical transport properties of InSe flakes electrostatically gated by a solid ion conductor.The large tuning capability of the solid ion conductor as gating dielectric is confirmed by the saturation gate voltage as low as^1 V and steep subthreshold swing(83 mV/dec).The p-type conduction behavior of InSe is obtained when negative gate voltages are biased.Chemical doping of the solid ion conductor is suppressed by inserting a buffer layer of hexagonal boron nitride(h-BN)between InSe and the solid-ion-conductor substrate.By comparing the performance of devices with and without h-BN,the capacitance of solid ion conductors is extracted to be the same as that of^2 nm h-BN,and the mobility of InSe on solid ion conductors is comparable to that on the SiO2 substrate.Our results show that solid ion conductors provide a facile and powerful method for electrostatic doping.展开更多
基金supported by the National Natural Science Foundation of China (52025132, 21621091, 22021001, 22121001, 22275207 and T2241022)the National Science Foundation of Fujian Province of China (2022J02059)+3 种基金the State Key Laboratory of Bio-Fibers and Eco-Textiles (Qingdao University) (KFKT202221)the 111 Project (B17027, B16029)the Science and Technology Projects of Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (RD2022070601)the Tencent Foundation (The XPLORER PRIZE)。
文摘Membrane separation technology with the ability to regulate gas/liquid transport and separation is critical for environmental fields, such as sewerage treatment, multiphase separation, and desalination. Although numerous membranes can dynamically control liquid-phase fluids transport via external stimuli, the transport and separation of gas-phase fluids remains a challenge. Here, we show a temperature-regulation liquid gating membrane that allows in-situ dynamically controllable gas/liquid transfer and multiphase separation by integrating a thermo-wettability responsive porous membrane with functional gating liquid. Experiments and theoretical analysis have demonstrated the temperature-regulation mechanism of this liquid gating system, which is based on thermo-responsive changes of porous membrane surface polarity, leading to changes in affinity between the porous membrane and the gating liquid. In addition, the sandwich configuration with dense Au-coated surfaces and heterogeneous internal components by a bistable interface design enables the liquid gating system to enhance response sensitivity and maintain working stability. This temperature-regulation gas/liquid transfer strategy expands the application range of liquid gating membranes,which are promising in environmental governance, water treatment and multiphase separation.
基金National Key R&D Program of China(No.2017YFA0304203)National Energy R&D Center of Petroleum Refining Technology(RIPP,SINOPEC),Changjiang Scholars and Innovative Research Team in University of Ministry of Education of China(IRT_17R70)+3 种基金National Natural Science Foundation of China(Nos.61975103,61875108,61775125 and 11434007)Major Special Science and Technology Projects in Shanxi(No.201804D131036)111 Project(No.D18001)Fund for Shanxi’1331KSC’。
文摘The self-absorption effect in laser-induced breakdown spectroscopy(LIBS)reduces the accuracy of quantitative measurement results.The self-absorption-free LIBS(SAF-LIBS)has been proved to directly capture the optically thin plasma spectra by setting an appropriate exposure time.In this work,a novel SAF-LIBS technique with high repetition rate acousto-optic gating is developed,in which an acousto-optic modulator is used as the shutter to diffract the optically thin fluorescence,and a high repetition rate laser is used to produce quasi-continuous plasmas to enhance the integral spectral intensity,so that the CCD spectrometer can replace an intensified CCD(ICCD)and echelle spectrometer in SAF-LIBS.Experimental results show that the average absolute prediction error of aluminum is reduced to 0.18%,which is equivalent to that of traditional SAF-LIBS.This technique not only effectively shields continuous background radiation and broadened spectral lines in optically thick plasma,but also has advantages of miniaturization,low cost,convenience and reliability.
基金This work was supported by the Provincial Key Projects for Scientifical and Technological Research of Zhejiang Province (No. 2006C12058)National Natural Science Foundation of China (No. 30571335) and a Grant-in-Aid for Innovative Training of Doctoral Students in JIangsu Province,China.
文摘Cyclic nucleotide-gated ion channels (CNGs) are distributed most widely in the neuronal cell. Great progress has been made in molecular mechanisms of CNG channel gating in the recent years. Results of many experiments have indicated that the stoichiometry and assembly of CNG channels affect their property and gating. Experiments of CNG mutants and analyses of cys- teine accessibilities show that cyclic nucleotide-binding domains (CNBD) bind cyclic nucleotides and subsequently conformational changes occurred followed by the concerted or cooperative conformational change of all four subunits during CNG gating. In order to provide theoretical assistances for further investigation on CNG channels, especially regarding the disease pathogenesis of ion channels, this paper reviews the latest progress on mechanisms of CNG channels, functions of subunits, processes of subunit assembly, and conformational changes of subunit regions during gating.
基金The Research Project of China Military Department (No6130325)
文摘A novel clock structure of a low-power 16-bit very large instruction word (VLIW) digital signal processor (DSP) was proposed. To improve deterministic clock gating and to solve the drawback of conventional clock gating circuit in high speed circuit, a distributed and early clock gating method was developed on its instruction fetch & decoder unit, its pipelined data-path unit and its super-Harvard memory interface unit. The core was implemented following the Synopsys back-end flow under TSMC (Taiwan Silicon manufacture corporation) 0.18-μm 1.8-V 1P6M process, with a core size of 2 mm×2 mm. Result shows that it can run under 200 MHz with a power performance around 0.3 mW/MIPS. Meanwhile, only 39.7% circuit is active simultaneously in average, compared to its non-gating counterparts.
基金funded by the Department of Science and Technology,Government of India(File No.SR/S3/MERC/0123/2009 dated 28.02.2011& Diary No.100/IFD/12365/2010-11 dated 28.02.2011)
文摘This work is concerned with the hydraulics and f low characterization in a pressurized,horizontal gating system with multiple ingates attached to a plate mold,using transparent water models.Runners with two different aspect ratios(w/h=0.5 and 2)and four different types of ingates(rectangular,convergent,divergent and venturi)were examined for their influence on flow behavior.Flow behavior was visualized using a high speed camera capable of capturing images up to 10,000 frames per second.Real time experimentation with a few runner–ingate combinations were carried out to validate the usefulness of water models in predicting the f illing behavior.Comparison of the approaches provided useful insights into the filling behavior in critical sections of the flow passages as well as the utility of water models towards understanding of the f illing behavior during real time casting.
基金supported by the Major Project of NSFC(51690161)the Student Innovation Program Major Project of Northeastern University(ZD1708)
文摘High pressure die casting(HPDC) is a kind of near net shape manufacturing method. However, air entrapment in HPDC parts has serious effects upon the casting quality. In order to reduce the air entrapment defects in a AlSi10 MnMg alloy thin-wall longitudinal load-bearing beam produced by HPDC, different gating systems were designed and simulated by software Flow-3D to evaluate the entrapped air. Simulation results showed that when the beam is produced by the original designed gating system with a middle ingate, there exist obvious air entrapments in the critical area; the volume of air entrapment was reduced by replacing the middle ingate to an overflow well, and the filling of molten metal became more stable. When the middle ingate was removed for further improvement, the volume of air entrapment was decreased drastically. The parts with glossy surface and good microstructure have been successfully produced by using the final optimized gating system based on simulation results.
基金supported by the National Natural Science Foundation of China under Grant Nos 51872328,11622437,11574394,11774423 and 11822412the Strategic Priority Research Program of Chinese Academy of Sciences under Grant No XDB30000000+5 种基金the Ministry of Science and Technology of China under Grant No 2016YFA0300504the Fundamental Research Funds for the Central Universitiesthe Research Funds of Renmin University of China(RUC)(15XNLQ07,18XNLG14,19XNLG17)supported by the National Natural Science Foundation of China under Grant Nos 11774007 and U1832214supported by the Outstanding Innovative Talents Cultivation Funded Programs 2018 of Renmin University of Chinasupported by the U.S. Department of Energy,Office of Science,Basic Energy Sciences,Division of Materials Sciences and Engineering
文摘We report protonation in several compounds by an ionic-liquid-gating method, under optimized gating conditions.This leads to single superconducting phases for several compounds. Non-volatility of protons allows post-gating magnetization and transport measurements. The superconducting transition temperature Tc is enhanced to 43.5 K for FeSe0.93S0.07, and 41 K for Fe Se after protonation. Superconducting transitions with Tc^15 K for ZrNCl,~7.2 K for 1-TaS2, and ~3.8 K for Bi2Se3 are induced after protonation. Electric transport in protonated FeSe0.93S0.07 confirms high-temperature superconductivity. Our ^1H nuclear magnetic resonance(NMR)measurements on protonated Fe Se1-xSx reveal enhanced spin-lattice relaxation rate 1/^1T1 with increasing x,which is consistent with the LDA calculations that H+ is located in the interstitial sites close to the anions.
文摘The gating system of a cylindrical magnesium casting has been designed by using multiple objective optimiza- tion and Taguchi method.Mold filling and solidification processes were simulated by using MAGMASOFT(?). The simulation results indicate that the gating system design has a significant effect on the quality of magne- sium castings.In an effort to obtain the optimal design of gating system,the signal-to-noise (S/N) ratio was used to analyze the effect of various gating designs on cavity filling and casting quality by using a weighting method based on the design of an orthogonal array.Four gating system parameters,namely,ingate height, ingate width,runner height,runner width,were optimized with a consideration of multiple objective criteria including filling velocity,shrinkage porosity and product yield.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11174294,11174291,11374302,11304319,U1332209,U1432251 and U1532153the China Postdoctoral Science Foundation under Grant No 2015M582020+1 种基金the Program of Users with Excellence,the Hefei Science Center of Chinese Academy of Sciencesthe CAS/SAFEA International Partnership Program for Creative Research Teams of China
文摘The electronic doping effect on both the superconductivity and the nematic order in the FeSe nanoflake are investigated by using the electric-double-layer transistor configuration. The superconductivity can be effectively controlled by electronic doping, and the onset superconducting transition temperature Tc reaches as high as 45 K at a gate voltage Of Vg = 4 V. Meanwhile, the nematic phase is gradually suppressed with the increase of electronic doping (or Vg). The results provide an effective method with variable charge doping for investigation of the rich physics in the FeSe superconductor.
基金supported by the National Natural Science Foundation of China(No.21773115,No.21833002,No.11771435,and No.22073110)the Natural Science Foundation of Jiangsu Province(No.BK20190056)the Fundamental Research Funds for the Central Universities(021514380018)。
文摘Calcium-release-activated calcium(CARC)channels are one of the major pathways of calcium entry in non-excitable cells.Despite a decade or two of research,its regulatory mechanism is not yet thoroughly understood.The slow progress is due to the complexity of its pores(i.e.,Orai)on one hand and the difficulty in capturing its regulatory complex on the other hand.As a result,possible gating mechanisms have often been speculated by exploring the structure and properties of constitutive open mutants.However,there is much debate about how they can truly reflect the gating of CRAC channels under physiological conditions.In the present study,we combined molecular dynamics simulations with free energy calculations to study three dOrai mutants(G170P,H206A,and P288A),and further calculated their current-voltage curves.Results show that these constructs adopt different approaches to maintain their conductive state.Meanwhile they have unique pore structures and distinctive rectification properties and ion selectivity for cations compared to wild-type pores.We conclude that although the mutants may partially capture the gating motion characteristics of wild-type pores,the information obtained from these mutants is likely not a true reflection of CRAC channel gating under physiological conditions.
基金Project supported by the National Key R&D Program of China(Grant No.2017YFB0405202)the National Natural Science Foundation of China(Grant Nos.61690221,91850209,and 11774277)。
文摘A convolutional neural network is employed to retrieve the time-domain envelop and phase of few-cycle femtosecond pulses from transient-grating frequency-resolved optical gating(TG-FROG) traces.We use theoretically generated TGFROG traces to complete supervised trainings of the convolutional neural networks,then use similarly generated traces not included in the training dataset to test how well the networks are trained.Accurate retrieval of such traces by the neural network is realized.In our case,we find that networks with exponential linear unit(ELU) activation function perform better than those with leaky rectified linear unit(LRELU) and scaled exponential linear unit(SELU).Finally,the issues that need to be addressed for the retrieval of experimental data by this method are discussed.
基金This work is supported by the National Nature Science Foundation of China(Grant Nos.61502101 and 61501247)the Natural Science Foundation of Jiangsu Province,China(Grant No.BK20171458)+4 种基金the Six Talent Peaks Project of Jiangsu Province,China(Grant No.2015-XXRJ-013)the Natural science Foundation for colleges and universities of Jiangsu Province,China(Grant No.16KJB520030)the Research Innovation Program for College Graduates of Jiangsu Province,China(Grant No.KYCX17_0902)the Practice Innovation Training Program Projects for the Jiangsu College Students(Grant No.201810300016Z)and the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘The delegating private quantum computation(DQC)protocol with the universal quantum gate set{X,Z,H,P,R,CNOT}was firstly proposed by Broadbent et al.[Broadbent(2015)],and then Tan et al.[Tan and Zhou(2017)]tried to put forward a half-blind DQC protocol(HDQC)with another universal set{H,P,CNOT,T}.However,the decryption circuit of Toffoli gate(i.e.T)is a little redundant,and Tan et al.’s protocol[Tan and Zhou(2017)]exists the information leak.In addition,both of these two protocols just focus on the blindness of data(i.e.the client’s input and output),but do not consider the blindness of computation(i.e.the delegated quantum operation).For solving these problems,we propose a full-blind DQC protocol(FDQC)with quantum gate set{H,P,CNOT,T},where the desirable delegated quantum operation,one of{H,P,CNOT,T},is replaced by a fixed sequence(H,P,CZ,CNOT,T)to make the computation blind,and the decryption circuit of Toffoli gate is also optimized.Analysis shows that our protocol can not only correctly perform any delegated quantum computation,but also holds the characteristics of data blindness and computation blindness.
文摘The main problems caused by improper gating are entrained aluminum oxide films and entrapped gas.In this study,the slot gating system is employed to improve mold filling behavior and therefore,to improve the quality of aluminum castings produced in permanent molds.An equipment as well as operation procedures for real-time X-ray radiography of molten aluminum flowing into permanent molds have been developed.Graphite molds transparent to X-rays are utilized which make it possible to observe the flow pattern through a number of vertically oriented gating systems.The investigation discovers that there are many influencing factors on the mold filling process.This paper focuses its research on some of the factors,such as the dimensions of the vertical riser and slot thickness,as well as roughness of the coating layer.The results indicate that molten metal can smoothly fill into casting cavity with a proper slot gating system.A bigger vertical riser,proper slot thickness and rougher coating can provide not only a better mold filling pattern,but also hot melt into the top of the cavity.A proper temperature gradient is obtainable,higher at the bottom and lower at the top of the casting cavity,which is in favor of feeding during casting solidification.
文摘In foundries a lot of effort is done to minimize energy consumption in the production to reduce costs and hence increase the competitiveness. At the same time the foundries must live up to the increased demands for high quality castings. Traditional gating systems are known for a straight tapered down runner, a well base and 90° bends in the runner system. Previous work has shown that the traditional way of designing gating systems creates high inconsistency in flow patterns during filling. In the streamlined gating systems there are no sharp changes in direction and a large effort is done to confine and control the flow of the molten metal during mould filling. The main objective in the work presented here is to use the principles of the streamlined gating systems to reduce the weight of the gating system relative to the traditional layouts. By reducing the weight of gating system and thereby improving yield, the amount of molten iron needed is also reduced, hence reducing the energy consumption for melting. Experiments in real production lines have proven that it is possible to achieve a reduction in the poured weight by using the streamlined gating systems. In a layout for casting of three valve housings in a vertically parted mould the weight of the gating system was reduced by 1.1 kg changing from the traditional layouts to the streamlined gating systems. This weight reduction corresponds in this case to a 20% weight reduction for the gating system. Using streamlined gating systems with fan gates to give a beneficial heat distribution in the castings may be an efficient tool to eliminate the need for heat treatment. In the experiments the change in gating system from the traditional layout to the streamlined layout removed the need for heat treatment. This obviously means a huge energy saving in the foundry. The energy consumption for heat treatment of iron has been found to be 0.489 kWh/ kg. The valve housing in the experiments weighs 3 kg so when the need for heat treatment is removed, around 1.5 kWh is saved per casting. Along with the reduction in energy used the foundry also save the cost of handling the castings for the heat treatment and the production times is reduced considerably When the moulds for the vertical layout is produced on a DISAMATIC that produces 350 moulds an hour the total energy saved per hour for both melting and heat treatment becomes 2,000 kWh and per eight hour work day 16,000 kWh. Seen in this perspective the potential for saving energy in the foundries is substantial. Furthermore the experiments where ductile iron valve housings was cast also proved that it is possible to lower the pouring temperature from 1,400℃ to 1,300℃ without the risk of cold runs. This is possible due to a high flow rate during mould filling in combination with low velocities due to the use of fan gates. All of this has also been investigated in experiments using glass plate fronted moulds.
基金Supported by the National Natural Science Foundation Program of China under Grant Nos 11274302,11474276 and 61290303
文摘The carrier-density-dependent spin relaxation dynamics for modulation-doped GaAs/Al0.3 Gao,TAs quantum wells is studied using the time-resolved magneto-Kerr rotation measurements. The electron spin relaxation time and its in-plane anisotropy are studied as a function of the optically injected electron density, Moreover, the relative strength of the Rashba and the Dresselhaus spin-rbit coupling fields, and thus the observed spin relaxation time anisotropy, is further tuned by the additional excitation of a 532nm continuous wave laser, demonstrating an effective spin relaxation manipulation via an optical gating method.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61605248 and 61505261)
文摘GHz single-photon detector (SPD) is a crucial part in the practical high speed quantum key distribution (QKD) system. However, any imperfections in a practical QKD system may be exploited by an eavesdropper (Eve) to collect information about the key without being discovered. The sine wave gating SPD (SG-SPD) based on InGaAs/InP avalanche photodiode, one kind of practical high speed SPD, may also contain loopholes. In this paper, we study the principle and characteristic of the SG-SPD and find out the filtering loophole of the SG-SPD for the first time. What is more, the proof-of-principle experiment shows that Eve could blind and control Bob's SG-SPD by exploiting this loophole. We believe that giving enough attention to this loophole can improve the practical security of the existing QKD system. GHz single-photon detector (SPD) is a crucial part in the practical high speed quantum key distribution (QKD) system. However, any imperfections in a practical QKD system may be exploited by an eavesdropper (Eve) to collect information about the key without being discovered. The sine wave gating SPD (SG-SPD) based on InGaAs/InP avalanche photodiode, one kind of practical high speed SPD, may also contain loopholes. In this paper, we study the principle and characteristic of the SG-SPD and find out the filtering loophole of the SG-SPD for the first time. What is more, the proof-of-principle experiment shows that Eve could blind and control Bob's SG-SPD by exploiting this loophole. We believe that giving enough attention to this loophole can improve the practical security of the existing QKD system.
基金Project supported by the Research Foundation of Education Bureau of Guangxi Autonomous Region of ChinaInitial Research Fund of Guangxi Normal University, and the Research Fund of Key Laboratory Construction in College of Electronic Engineering of Guangxi Normal University
文摘The classical model of voltage-gated ion channels assumes that according to a Markov process ion channels switch among a small number of states without memory, but a bunch of experimental papers show that some ion channels exhibit significant memory effects, and this memory effects can take the form of kinetic rate constant that is fractal. Obviously the gating character of ion channels will affect generation and propagation of action potentials, furthermore, affect generation, coding and propagation of neural information. However, there is little previous research on this series of interesting issues. This paper investigates effects of fractal gating of potassium channel subunits switching from closed state to open state on neuronal behaviours. The obtained results show that fractal gating of potassium channel subunits switching from closed state to open state has important effects on neuronal behaviours, increases excitability, rest potential and spiking frequency of the neuronal membrane, and decreases threshold voltage and threshold injected current of the neuronal membrane. So fractal gating of potassium channel subunits switching from closed state to open state can improve the sensitivity of the neuronal membrane, and enlarge the encoded strength of neural information.
基金Project supported by the National Key Research and Development Projects of China(Grant Nos.2016YFA0202300 and 2018FYA0305800)the National Natural Science Foundation of China(Grant Nos.61674170 and 61888102)+1 种基金the K.C.Wong Education Foundation,the Strategic Priority Research Program of Chinese Academy of Sciences(Grant Nos.XDB30000000 and XDB28000000)the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.Y201902).
文摘We report the electrical transport properties of InSe flakes electrostatically gated by a solid ion conductor.The large tuning capability of the solid ion conductor as gating dielectric is confirmed by the saturation gate voltage as low as^1 V and steep subthreshold swing(83 mV/dec).The p-type conduction behavior of InSe is obtained when negative gate voltages are biased.Chemical doping of the solid ion conductor is suppressed by inserting a buffer layer of hexagonal boron nitride(h-BN)between InSe and the solid-ion-conductor substrate.By comparing the performance of devices with and without h-BN,the capacitance of solid ion conductors is extracted to be the same as that of^2 nm h-BN,and the mobility of InSe on solid ion conductors is comparable to that on the SiO2 substrate.Our results show that solid ion conductors provide a facile and powerful method for electrostatic doping.