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A mechanically robust egg white hydrogel scaffold with excellent biocompatibility by three-step green processing

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Science China(Technological Sciences) 2022年第7期65卷 1599-1612页

作者： WEI Zhen-Zhen DONG Xuan zhang Yu-qing School of Biology and Basic Medical Sciences Medical CollegeSoochow UniversitySuzhou 215123China College of Chemistry Chemical Engineering and Materials ScienceSoochow UniversitySuzhou 215123China

Egg white(EW) is one of the most common and high-quality nutritional proteins. A novel three-step green processing technology is constructed to process homogeneous EW into a mechanically robust EW hydrogel scaffold(EWHS) with excellent biocompatibility. The homogeneous EW is first treated with stream to form a hydrogel, then slowly dehydrated to form a fragile and almost transparent EW glass, and finally annealed into an EWHS. The EWHS is water-insoluble, wet soft and translucent and has a porous network structure, and its pore size distribution is between 0.1–1.0 μm. The tensile strength in wet state is as high as 5.0 MPa, the elongation at break is about 93%, and the swelling rate is about 85%. The order of the enzymatically residual rate of these EWHSs is pepsin > neutral protease > papain> trypsin > alkaline protease. Mouse L929 cells can adhere,proliferate, and grow well on the EWHSs. After EWHS was implanted in rats for three weeks, the levels of IL-6, TNF-α, and NF-κB inflammatory factors did not change significantly in comparison with the pseudo-operated and normal groups. This novel EW hydrogel biomaterial has potential applications in medical 3 D tissue engineering materials, such as tendons, soft tissues, and in vivo implants.

关键词： egg white hydrogel scaffolds dehydration heat treatment mechanical properties swelling rate

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Phase plane design based fast altitude tracking control for hypersonic flight vehicle with angle of attack constraint

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Chinese Journal of Aeronautics 2021年第2期34卷 490-503页

作者： Yang LIU Chaoyang DONG Wenqiang zhang qing WANG School of Aeronautic Science and Engineering Beihang UniversityBeijing 100083China School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100083China

In this paper, fast setpoint altitude tracking control for Hypersonic Flight Vehicle(HFV)satisfying Angle of Attack(AOA) constraint is studied with a two-loop structure controller, in the presence of parameter uncertainties and disturbances. For the outer loop, phase plane design is adopted for the simplified model under Bang-Bang controller to generate AOA command guaranteeing fast tracking performance. Modifications based on Feedback-Linearization(FL) technique are adopted to transform the phase trajectory into a sliding curve. Moreover, to resist mismatch between design model and actual model, Fast Exponential Reaching Law(FERL) is augmented with the baseline controller to maintain state on the sliding curve. The inner-loop controller is based on backstepping technique to track the AOA command generated by outer-loop controller. Barrier Lyapunov Function(BLF) design is employed to satisfy AOA requirement. Moreover, a novel auxiliary state is introduced to remove the restriction of BLF design on initial tracking errors. Dynamic Surface Control(DSC) is utilized to ease the computation burden. Rigorous stability proof is then given, and AOA is guaranteed to stay in predefined region theoretically. Simulations are conducted to verify the efficiency and superior performance of the proposed method.

关键词： Adaptive control Angle of attack constraints Barrier Lyapunov function Hypersonic flight vehicle Phase plane design Reaching law design

A neuromorphic core based on threshold switching memristor with asynchronous address event representation circuits

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Science China(Information Sciences) 2022年第2期65卷 211-217页

作者： Jinsong WEI Jilin zhang Xumeng zhang Zuheng WU Rui WANG Jian LU tuo SHI Mansun CHAN Qi LIU Hong CHEN School of Microelectronics University of Science and Technology of China Institute of Microelectronics of Chinese Academy of Sciences Zhejiang Lab Department of Microelectronics and Nanoelectronics Tsinghua University Department of Electronic & Computer Engineering The Hong Kong University of Science and Technology

The full memristive network hardware features high density and excellent scalability. However,recent researches on the full memristive network have been limited to a single-layer network, due to the lack of effective and flexible communication between neurons. In this design, we demonstrate a neuromorphic core based on Ag/Si O2/Au threshold switching memristor, which has built-in asynchronous address event representation(AER) circuits to provide flexible communication between neurons. Since temporally sparse spikes are the medium of communication between neurons, the AER circuits are designed to transmit spikes serially which have been encoded with neurons’ addresses before transmission. With the asynchronous circuits design, the AER circuits will detect neurons’ output in real-time. To test the performance of the neuromorphic core, we designed a behavioral simulator for the neuromporphic core to simulate the liquid state machine(LSM) network, which achieves a 100% recognition rate in the free spoken digital dataset. The simulation results show that the neuromorphic core obtains 35 times higher performance than the CPU and111 times higher energy efficiency than the GPU.

关键词： leaky-integration-and-fire (LIF) memristor threshold switching artificial neuron AER circuits asynchronous circuits on-chip communication

Constructing Low-Dimensional Quantum Devices Based on the Surface State of Topological Insulators

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Chinese Physics Letters 2021年第7期38卷 116-121页

作者： Tian-Yi zhang qing Yan qing-Feng Sun School of Physical Science and Technology Soochow UniversitySuzhou 215006China International Center for Quantum Material School of PhysicsPeking UniversityBeijing 100871China Collaborative Innovation Center of Quantum Matter Beijing 100871China CAS Center for Excellence in Topological Quantum Computation University of Chinese Academy of SciencesBeijing 100190China

We propose a new method to construct low-dimensional quantum devices consisting of the magnetic topological *** previous systems based on locally depleting two-dimensional electron gas in semiconductor heterojunctions,magnetization provides a simpler and rewriteable fabrication *** motion of electrons can be manipulated through the domain wall formed by the boundary between different magnetic ***,three devices designed by local magnetization are *** the quantum point contact,conductance exhibits quantized plateaus with the increasing silt width between two magnetic *** the quantum dot,conductance shows pronounced peaks as the change of gate ***,for the Aharonov–Bohm ring,conductance oscillates periodically with the external magnetic *** results show that the transport of these local magnetization systems is identical to that of the previous systems based on depleting two-dimensional electron gas,and the only difference is the approach of *** findings may pave the way for realization of low-power-consumption devices based on magnetic domain walls.

关键词： field magnetization quantum

Novel Stability Criteria for Linear Time-Delay Systems Using Lyapunov-Krasovskii Functionals With A Cubic Polynomial on Time-Varying Delay

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IEEE/CAA Journal of Automatica Sinica 2021年第1期8卷 77-85页

作者： Xian-Ming zhang qing-Long Han Xiaohua Ge the School of Software and Electrical Engineering Swinburne University of TechnologyMelbourneVIC 3122Australia

One of challenging issues on stability analysis of time-delay systems is how to obtain a stability criterion from a matrix-valued polynomial on a time-varying *** first contribution of this paper is to establish a necessary and sufficient condition on a matrix-valued polynomial inequality over a certain closed *** degree of such a matrix-valued polynomial can be an arbitrary finite positive *** second contribution of this paper is to introduce a novel LyapunovKrasovskii functional,which includes a cubic polynomial on a time-varying delay,in stability analysis of time-delay *** on the novel Lyapunov-Krasovskii functional and the necessary and sufficient condition on matrix-valued polynomial inequalities,two stability criteria are derived for two cases of the time-varying delay.A well-studied numerical example is given to show that the proposed stability criteria are of less conservativeness than some existing ones.

关键词： Bessel-Legendre inequality matrix-valued polynomial inequalities stability time-varying delay time-delay systems

Improved Oxygen Evolution Kinetics and Surface States Passivation of Ni-Bi Co-Catalyst for a Hematite Photoanode

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Engineering 2017年第3期3卷 285-289页

作者： Ke Dang tuo Wang Chengcheng Li Jijie zhang Shanshan Liu Jinlong Gong Key Laboratory for Green Chemical Technology of Ministry of Education School of Chemical Engineering and Technology Tianjin University. Tianjin 300072 China Collaborative Innovation Center of Chemical Science and Engineering Tianjin 300072 China

This paper describes the combinational surface kinetics enhancement and surface states passivation of nickel-borate （Ni-Bi） co-catalyst for a hematite （Fe_2O_3） photoanode. The Ni-Brmodified Fe_2O_3 photoanode exhibits a cathodic onset potential shift of 230 mV and a 2.3-fold enhancement of the photocurrent at 1.23 V, versus the reversible hydrogen electrode （RHE）. The borate （Bi） in the Ni-Bi film promotes the release of pro- tons for the oxygen evolution reaction （OER）.

关键词： Nickel-borate Hematite Oxygen evolution reaction Co-catalyst

A Type-2 Fuzzy Approach to Driver-Automation Shared Driving Lane Keeping Control of Semi-Autonomous Vehicles Under Imprecise Premise Variable

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Chinese Journal of Mechanical Engineering 2022年第2期35卷 210-227页

作者： Yue Liu qing Xu Hongyan Guo Hui zhang School of Transportation Science and Engineering Beihang UniversityBeijing 100091China School of Vehicle and Mobility Tsinghua UniversityBeijing 100000China College of Automotive Engineering Jilin UniversityChangchun 130000China

The driver-automation shared driving is a transition to fully-autonomous driving,in which human driver and vehicular controller cooperatively share the control *** paper investigates the shared steering control of semi-autonomous vehicles with uncertainty from imprecise *** considering driver’s lane-keeping behavior on the vehicle system,a driver-automation shared driving model is introduced for control *** on the interval type-2(IT2)fuzzy theory,moreover,the driver-automation shared driving model with uncertainty from imprecise parameter is described using an IT2 fuzzy *** that,the corresponding IT2 fuzzy controller is designed and a direct Lyapunov method is applied to analyze the system *** this work,sufficient design conditions in terms of linear matrix inequalities are derived,to guarantee the closed-loop stability of the driver-automation shared control *** addition,an H∞performance is studied to ensure the robustness of control ***,simulation-based results are provided to demonstrate the performance of proposed control ***,an existing type-1 fuzzy controller is introduced as comparison to verify the superiority of the proposed IT2 fuzzy controller.

关键词： Driver-automation shared control Fuzzy control Interval type-2 fuzzy system Autonomous vehicles

Insight-HXMT observations of the Crab pulsar

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Research in Astronomy and Astrophysics 2019年第6期19卷 109-116页

作者： You-Li tuo Ming-Yu Ge Li-Ming Song Lin-Li Yan qing-Cui Bu Jin-Lu Qu Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China University of the Chinese Academy of Sciences Beijing 100049 China School of Mathematics and Physics Anhui Jianzhu University Hefei 230601 China

We report on X-ray emission properties of the Crab pulsar(PSR B0531+21) using observations by Insight-HXMT during its first year after launch. We obtained high signal-to-noise profiles in the X-ray energy band 11–250 keV. We have confirmed an increase in the flux ratio of the second peak over the main peak with increasing energy, consistent with other missions. The separation of the two peaks shows no significant trend with increasing energy. The phase-averaged spectrum, fitted by a logpar model, and the phase-resolved spectra of the Crab pulsar, fitted by a powerlaw in the different energy bands of HXMT, are consistent with RXTE and NuSTAR in that photon indices evolve as a function of phase as well as a function of energy, contributing to a broadband modeling.

关键词： stars neutron star-pulsars individual(Crab)-X-rays

Bi-variable damage model for fatigue life prediction of metal components

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Acta Mechanica Sinica 2011年第3期27卷 416-425页

作者： Miao zhang qing-Chun Meng Xing zhang Wei-Ping Hu Division 508 School of Aeronautic Science and Engineering Beihang University 100191 Beijing China

Based on the theory of continuum damage mechanics,a bi-variable damage mechanics model is developed,which,according to thermodynamics,is accessible to derivation of damage driving force,damage evolution equation and damage evolution criteria. Furthermore,damage evolution equations of time rate are established by the generalized Drucker＇s postulate. The damage evolution equation of cycle rate is obtained by integrating the time damage evolution equations,and the fatigue life prediction method for smooth specimens under repeated loading with constant strain amplitude is constructed. Likewise,for notched specimens under the repeated loading with constant strain amplitude,the fatigue life prediction method is obtained on the ground of the theory of conservative integral in damage mechanics. Thus,the material parameters in the damage evolution equation can be obtained by reference to the fatigue test results of standard specimens with stress concentration factor equal to 1,2 and 3.

关键词： Bi-variable damage model - Damage evolution equation . Life prediction - Fatigue . Damage mechanics