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Rational surface charge engineering of haloalkane dehalogenase for boosting the enzymatic performance in organic solvent solutions

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Chinese Journal of Chemical Engineering 2024年第1期65卷 276-285页

作者： Yin wu Yan Sun Department of Biochemical Engineering School of Chemical Engineering and Technology and Key Laboratory of Systems Bioengineering and Frontiers Science Center for Synthetic Biology(Ministry of Education)Tianjin UniversityTianjin 300350China

Biocatalysis in organic solvents(OSs)has numerous important applications,but native enzymes in OSs often exhibit limited catalytic ***,we proposed a computation-aided surface charge engineering strategy to improve the catalytic performance of haloalkane dehalogenase DhaA in OSs based on the energetic analysis of substrate binding to the DhaA *** variants with enhanced OS resistance were obtained by replacing negative charged residues on the surface with positive charged residue(Arg).Particularly,a four-substitution variant E16R/E93R/E121R/E257R exhibited the best catalytic performance(five-fold improvement in OS resistance and seven-fold half-life increase in 40%(vol)dimethylsulfoxide).As a result,the overall catalytic performance of the variant could be at least 26 times higher than the wild-type *** spectroscopy and molecular dynamics simulation studies revealed that the residue substitution mainly enhanced OS resistance from four aspects:(a)improved the overall structural stability,(b)increased the hydrophobicity of the local microenvironment around the catalytic triad,(c)enriched the hydrophobic substrate around the enzyme molecule,and(d)lowered the contact frequency between OS molecules and the catalytic *** findings validate that computationaided surface charge engineering is an effective and ingenious rational strategy for tailoring enzyme performance in OSs.

关键词： Surface charge engineering Organic solvent resistance Molecular dynamics simulation Haloalkane dehalogenase

Dual-ion carrier storage through Mg^(2+) addition for high-energy and long-life zinc-ion hybrid capacitor

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International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 179-185页

作者： Junjie Zhang Xiang wu School of Materials Science and Engineering Shenyang University of TechnologyShenyang 110870China

Cation additives can efficiently enhance the total electrochemical capabilities of zinc-ion hybrid capacitors (ZHCs).However their energy storage mechanisms in zinc-based systems are still under ***,we modulate the electrolyte and achieve dual-ion storage by adding magnesium *** we assemble several Zn//activated carbon devices with different electrolyte concentrations and investigate their electrochemical reaction dynamic *** zinc-ion capacitor with Mg^(2+)mixed solution delivers 82 mAh·g^(-1)capacity at 1 A·g^(-1) and maintains 91%of the original capacitance after 10000 *** is superior to the other assembled zinc-ion devices in single-component *** finding demonstrates that the double-ion storage mechanism enables the superior rate performance and long cycle lifetime of ZHCs.

关键词： zinc-ion hybrid capacitor MgSO_(4) electrolyte rate performance storage mechanism

Partially-Observed Maximum Principle for Backward Stochastic Differential Delay Equations

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IEEE/CAA Journal of Automatica Sinica 2024年第6期11卷 1524-1526页

作者： Shuang wu Department of Applied Mathematics China University of PetroleumQingdao 266580China

Dear Editor,This letter investigates a partially-observed optimal control problem for backward stochastic differential delay equations(BSDDEs).By utilizing Girsanov’s theory and convex variational method,we obtain a maximum principle on the assumption that the state equation contains time delay and the control domain is *** adjoint processes can be represented as the solutions of certain time-advanced stochastic differential equations in finite-dimensional *** backward stochastic differential equation(BSDE)was first introduced by Bismut in[1],while general BSDE was given by Pardoux and Peng[2].Since then,the theory of BSDEs developed *** corresponding optimal control problems,whose states are driven by BSDEs,have also been widely studied by some authors,see[3]-[5].

关键词： stochastic backward convex

Recent advances and key perspectives of in-situ studies for oxygen evolution reaction in water electrolysis

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Green Energy & Environment 2024年第10期9卷 1497-1517页

作者： Yi Wang Zichen Xu Xianhong wu Zhong-Shuai wu State Key Laboratory of Catalysis Dalian Institute of Chemical Physics Chinese Academy of Sciences University of Chinese Academy of Sciences Shijingshan District Dalian National Laboratory for Clean Energy Chinese Academy of Sciences

Electricity-driven water splitting to produce hydrogen is one of the most efficient ways to alleviate energy crisis and environmental pollution problems, in which the anodic oxygen evolution reaction(OER) is the key half-reaction of performance-limiting in water splitting. Given the complicated reaction process and surface reconstruction of the involved catalysts under actual working conditions, unraveling the real active sites, probing multiple reaction intermediates and clarifying catalytic pathways through in-situ characterization techniques and theoretical calculations are essential. In this review, we summarize the recent advancements in understanding the catalytic process, unlocking the water oxidation active phase and elucidating catalytic mechanism of water oxidation by various in-situ characterization techniques. Firstly, we introduce conventionally proposed traditional catalytic mechanisms and novel evolutionary mechanisms of OER, and highlight the significance of optimal catalytic pathways and intrinsic stability. Next, we provide a comprehensive overview of the fundamental working principles,different detection modes, applicable scenarios, and limitations associated with the in-situ characterization techniques. Further, we exemplified the in-situ studies and discussed phase transition detection, visualization of speciation evolution, electronic structure tracking, observation of reaction active intermediates, and monitoring of catalytic products, as well as establishing catalytic structure–activity relationships and catalytic mechanism. Finally, the key challenges and future perspectives for demystifying the water oxidation process are briefly proposed.

关键词： In-situ studies Water splitting Oxygen evolution reaction Catalytic mechanism

Enhancing performance of low-temperature processed CsPbI2Br all-inorganic perovskite solar cells using polyethylene oxide-modified TiO_(2)

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International Journal of Minerals,Metallurgy and Materials 2024年第4期31卷 786-794页

作者： Xu Zhao Naitao Gao Shengcheng wu Shaozhen Li Sujuan wu School of Electrical and Electronic Engineering Wuhan Polytechnic UniversityWuhan 430023China Institute for Advanced Materials and Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials South China Academy of Advanced OptoelectronicsSouth China Normal UniversityGuangzhou 510006China

CsPbX_(3)-based(X=I,Br,Cl)inorganic perovskite solar cells(PSCs)prepared by low-temperature process have attracted much attention because of their low cost and excellent thermal ***,the high trap state density and serious charge recombination between low-temperature processed TiO_(2)film and inorganic perovskite layer interface seriously restrict the performance of all-inorganic *** a thin polyethylene oxide(PEO)layer is employed to modify TiO_(2)film to passivate traps and promote carrier *** impacts of PEO layer on microstructure and photoelectric characteristics of TiO_(2)film and related devices are systematically *** results suggest that PEO modification can reduce the surface roughness of TiO_(2)film,decrease its average surface potential,and passivate trap *** optimal conditions,the champion efficiency of CsPbI_(2)Br PSCs with PEO-modified TiO_(2)(PEO-PSCs)has been improved to 11.24%from 9.03%of reference ***,the hysteresis behavior and charge recombination have been suppressed in PEO-PSCs.

关键词： polyethylene oxide-modified TiO_(2) film low-temperature process CsPbI_(2)Br-based all-inorganic perovskite solar cells photo-voltaic performance

A GNSS Anti-Spoofing Technique Based on the Spatial Distribution Characteristic of the Residual Vectors

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Tsinghua Science and Technology 2024年第2期29卷 457-468页

作者： Qi'an wu Xiaowei Cui Mingquan Lu Pengxiang Yang Peng wu Department of Electronic Enginnering Tsinghua UniversityBeijing 100084China Xi’an Modern Control Technology Research Institute Xi’an 710065China

Anti-spoofing is becoming a crucial technique for applications with high navigation accuracy and reliability ***-spoofing technique based on Receiver Autonomous Integrity Monitoring(RAIM)is a good choice for most Global Navigation Satellite System(GNSS)receivers because it does not require any change to the hardware of the ***,the conventional RAIM method can only detect and mitigate a single spoofing *** improved RAIM methods can deal with more spoofing signals,but the computational complexity increases dramatically when the number of satellites in view increase or need additional *** paper proposes a new RAIM method,called the SRV-RAIM method,which has a very low computation complexity regardless of the number of satellites in view and can deal with any number of spoofing *** key to the new method is the spatial distribution characteristic of the Satellites'Residual Vectors(SRV).In replay or generative spoofing scenarios,the pseudorange measurements of spoofing signals are consistent,the residual vectors of real satellites and those of spoofing satellites have good separation characteristics in spatial *** on this characteristic,the SRV-RAIM method is proposed,and the simulation results show that the method can separate the real signals and the spoofing signals with an average probability of 86.55%in the case of 12 visible satellites,regardless of the number of spoofing *** to the conventional traversal-RAIM method,the performance is only reduced by 3.59%,but the computational cost is reduced by 98.3%,so most of the GNSS receivers can run the SRV-RAIM algorithm in time.

关键词： Global Navigation Satellite System(GNSS) anti-spoofing Receiver Autonomous Integrity Monitoring(RAIM) Satellites'Residual Vectors(SRV)

Effective Identity Authentication Based on Multiattribute Centers for Secure Government Data Sharing

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Tsinghua Science and Technology 2024年第3期29卷 736-752页

作者： Meiquan Wang Junhua wu Tongdui Zhang Junhao wu Guangshun Li School of Computer Science Qufu Normal UniversityRizhao 276800China Science and Technology Innovation Service Institution of Rizhao Rizhao 276800China

As one of the essential steps to secure government data sharing,Identity Authentication(IA)plays a vital role in the processing of large ***,the centralized IA scheme based on a trusted third party presents problems of information leakage and single point of failure,and those related to key ***,herein,an effective IA model based on multiattribute centers is ***,a private key of each attribute of a data requester is generated by the attribute authorization *** obtaining the private key of attribute,the data requester generates a personal private ***,a dynamic key generation algorithm is proposed,which combines blockchain and smart contracts to periodically update the key of a data requester to prevent theft by external attackers,ensure the traceability of IA,and reduce the risk of privacy ***,the combination of blockchain and interplanetary file systems is used to store attribute field information of the data requester to further reduce the cost of blockchain information storage and improve the effectiveness of information *** results show that the proposed model ensures the privacy and security of identity information and outperforms similar authentication models in terms of computational and communication costs.

关键词： blockchain identity authentication distribution dynamic key generation

Design and Implementation of Nonlinear Precoding for MIMO-SDMA Toward 6G Wireless

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China Communications 2024年第1期21卷 69-87页

作者： Chaowu wu Yue Xiao Shu Fang Gang wu National Key Laboratory of Wireless Communications University of Electronic Science and Technology of ChinaChengdu 611731China

In this paper,we present a novel and robust nonlinear precoding(NLP)design and detection structure specifically tailored for multiple-input multipleoutput space division multiple access(MIMO-SDMA)systems toward 6G *** approach aims to effectively mitigate the impact of imperfect channel estimation by leveraging the channel fluctuation mean square error(MSE)for reconstructing a highly accurate precoding matrix at the ***,we introduce a simplified receiver structure that eliminates the need for equalization,resulting in reduced interference and notable enhancements in overall system *** conduct both computer simulations and experimental tests to validate the efficacy of our proposed *** results reveals that the proposed NLP scheme offers significant performance improvements,making it particularly well-suited for the forthcoming 6G wireless.

关键词： MIMO-SDMA nonlinear precoding Tomlinson-Harashima precoding(THP) vector perturbation(VP)

Optically levitated micro gyroscopes with an MHz rotational vaterite rotor

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Microsystems & Nanoengineering 2024年第3期10卷 219-227页

作者： Kai Zeng Xiangming Xu Yulie wu Xuezhong wu Dingbang Xiao College of Intelligence Science and Technology National University of Defense TechnologyChangsha 410073China College of Information and Communication National University of Defense TechnologyWuhan 430000China Key Laboratory of Satellite Navigation Technology National University of Defense TechnologyChangsha 410073China

The field of levitated optomechanics has experienced significant advancements in manipulating the translational and rotational dynamics of optically levitated particles and exploring their sensing *** concept of using optically levitated particles as gyroscopes to measure angular motion has long been explored but has not yet been proven either theoretically or *** this study,we present the first rotor gyroscope based on optically levitated high-speed rotating *** gyroscope is composed of a micrometer-size ellipsoidal vaterite particle that is driven to rotate at MHz frequencies in a vacuum *** an external angular velocity is input,the optical axis deviates from its initial position,resulting in changes in the frequency and amplitude of the rotational *** analyzing these changes,the angular velocity of the input can be accurately detected,making it the smallest rotor gyroscope in the *** angular rate bias instability of the gyroscope is measured to be 0.08°/s and can be further improved to as low as 10^(−9)°/h theoretically by cooling the motion and increasing the angular moment of the levitated *** work opens a new application paradigm for levitated optomechanical systems and may pave the way for the development of quantum rotor gyroscopes.

关键词： particles rotational angular