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Using single-molecule approach to visualize the nucleosome assembly in yeast nucleoplasmic extracts

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Science Bulletin 2017年第6期62卷 399-404页

作者： Xiuqiang Chen Ershuang Zhao yu V.Fu State Key Laboratory of Microbial Resources Institute of MicrobiologyChinese Academy of Sciences Savaid Medical School University of Chinese Academy of Sciences

In eukaryotic cells,the smallest subunit of chromatin is the nucleosome,which consists of a segment of DNA wound on histone protein cores. Despite many years of effort,the process of nucleosome assembly and disassembly is still not very clear. Here,we present a convenient method to investigate the process of nucleosome assembly at the single molecule level. We invented a novel system derived from the yeast nucleoplasmic extracts(YNPE),and demonstrated that the YNPE supports the nucleosome assembly under physiological condition. By combining the total internal reflection fluorescence microscopy with microfluidic flow-cell technique,the dynamic process of nucleosome assembly in YNPE was visualized at single-molecule level. Our system provides a novel in vitro single-molecule tool to investigate the dynamics of nucleosome assembly under physiological conditions.

关键词： Nucleosome assembly Single-molecule Yeast nucleoplasmic extracts Total internal reflection fluorescence Microfluidic flow-cell

Exploring the potential of constructing a hybrid supercapacitor with FeCoNi-LDH porous material containing oxygen vacancies for high-performance energy storage applications

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Nano Research 2024年第9期17卷 8134-8144页

作者： Jihao Su Ling Yang Dengbin yu Shaojun Dong State Key Laboratory of Electroanalytical Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China College of Chemistry Jilin UniversityChangchun 130022China University of Science and Technology of China Hefei 230026China

A significant challenge in developing high-performance hybrid supercapacitors(HSCs)is the need to reasonably construct advanced architectures that consist of various components and exhibit superior electrochemical capacitance *** FeCoNi-layered double hydroxide(FeCoNi-LDH)porous material has a specific capacitance of 1960 F·g^(-1)when used as the anode material at 1 A·g^(-1).The FeCoNi-LDH material exhibits nanoplates with a distinct spindle morphology on their *** to the combined action of the three metals and abundant oxygen vacancies,they exhibit unique rate performance and cycle *** electronic structure of LDH and the regulation of oxygen vacancy were confirmed by density functional theory(DFT)*** suggests that the strength of hydroxide can reduce the energy required for oxygen vacancy formation in FeCoNi-LDH nanosheets and enhance ion and charge transfer,as well as electrolyte adsorption on the electrode *** FeCoNi-LDH//activated carbon(AC)HSC has an energy density of 53.2 Wh·kg^(-1)at a power density of 800 W·kg^(-1),surpassing other devices composed of comparable materials during the same *** study made significant advances in the design and synthesis of a ternary LDH porous structure with distinct oxygen vacancies,as well as its potential application in electrochemical energy storage.

关键词： oxygen vacancy FeCoNi-layered double hydroxide(FeCoNi-LDH) theory calculation electrode material hybrid supercapacitor

Controlling the entropic uncertainty and quantum discord in two two-level systems by an ancilla in dissipative environments

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Chinese Physics B 2021年第3期30卷 441-446页

作者： Rong-yu Wu Mao-Fa Fang Synergetic Innovation Center for Quantum Effects and Application Key Laboratory of Low-dimensional Quantum Structures and Quantum Control of Ministry of EducationSchool of Physics and ElectronicsHunan Normal UniversityChangsha 410081China

The uncertainty principle is a crucial aspect of quantum *** has been shown that the uncertainty principle can be tightened by quantum discord and classical correlation in the presence of quantum *** investigate the control of the entropic uncertainty and quantum discord in two two-level systems by an ancilla in dissipative *** results show that the entropic uncertainty of an observed system can be reduced and the quantum discord between the observed system and the quantum memory system can be enhanced in the steady state of the system by adding an dissipative ***,via preparing the state of the system to the highest excited state with hight fidelity,the entropic uncertainty can be reduced markedly and the quantum discord can be enhanced *** explain these results using the definition of state ***,we present an effective strategy to further reduce the the entropic uncertainty and to enhance the the quantum discord via quantum-jump-based feedback ***,our results may be of importance in the context of quantum information technologies.

关键词： entropic uncertainty quantum discord dissipative environment ancilla

First-principle study on the physical properties of ultra-incompressible ReB_2

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Acta Metallurgica Sinica(English Letters) 2009年第4期22卷 284-290页

作者： Chunlei WANG Qiuju SUN Xuanyu SONG Benhai yu College of Physics and Electronic Engineering Xinyang Normal University Xinyang 464000 China

The elastic and physical characteristics of ReB2 crystal have been predicted through a method of density functional theory within the generalized gradient approximation （GGA）. Five independent elastic constants are C11=662 GPa, C12=150 GPa, C13=146 GPa, C33=1090 GPa and Caa=263 GPa. The bulk modulus （B）, shear modulus （G）, Young＇s modulus （E）, Poisson＇s ratio （γ） and the ratio of linear com- pressibility coefficient along the a- and c-axis crystal direction （Ka/Kc） are 356 GPa, 305 GPa, 711 GPa, 0.167 and 1.758, respectively. In addition, the dependence of bulk modulus （B） on temperature （T） and pressure （p） as well as the coefficient of thermal expansion （αL） at various temperatures are evaluated and discussed. The coefficient of thermal expansion is consistent with the famous Grüneisen＇s law when the temperature is less than 1500 K. Our results agree well with the other experimental results.

关键词： Rhenium diboride Density functional calculations Bulk modulus Coefficient of thermal expansion

Capability-based context ontology modeling and reasoning for C^4ISR communication

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Journal of Systems Engineering and Electronics 2016年第4期27卷 845-857页

作者： Weixing Zhu Zhixue Wang Guolin Hou Minggang yu Institute of Command Information System PLA University of Science and TechnologyNanjing 210007China The First Engineers Scientfic Research Institute of General Armaments Department Wuxi 214035China

Modeling and reasoning on domain contexts play a key role for adding intelligence to communication services, and the approach of capability-based requirement engineering ensures the scientificity and accuracy of requirement elicitation. This paper presents a capability-based context ontology modeling approach for command and control, communication, computer, intelligence, surveillance and reconnaissance（C^4ISR） communication. Primarily, a capability-based C^4ISR communication meta-concept model and a C^4ISR communication context meta-ontology are constructed. The context ontology is established under the constraints of the C^4ISR communication context meta-ontology, and furthermore, algorithms are proposed to support context reasoning based on description logic. A case study is presented to demonstrate applicability of the proposed method.

关键词： service intelligentizing C4ISR communication context ontology context reasoning

Synthesis of indirect work exchange networks considering both isothermal and adiabatic process together with exergy analysis

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Chinese Journal of Chemical Engineering 2018年第8期26卷 1644-1652页

作者： yu Zhuang Linlin Liu Lei Zhang Jian Du Institute of Chemical Process Systems Engineering School of Chemical Engineering Dalian University of Technology

In this paper, an efficient methodology for synthesizing the indirect work exchange networks(WEN) considering isothermal process and adiabatic process respectively based on transshipment model is first proposed. In contrast with superstructure method, the transshipment model is easier to obtain the minimum utility consumption taken as the objective function and more convenient for us to attain the optimal network configuration for further minimizing the number of units. Different from division of temperature intervals in heat exchange networks,different pressure intervals are gained according to the maximum compression/expansion ratio in consideration of operating principles of indirect work exchangers and the characteristics of no pressure constraints for stream matches. The presented approach for WEN synthesis is a linear programming model applied to the isothermal process, but for indirect work exchange networks with adiabatic process, a nonlinear programming model needs establishing. Additionally, temperatures should be regarded as decision variables limited to the range between inlet and outlet temperatures in each sub-network. The constructed transshipment model can be solved first to get the minimum utility consumption and further to determine the minimum number of units by merging the adjacent pressure intervals on the basis of the proposed merging methods, which is proved to be effective through exergy analysis at the level of units structures. Finally, two cases are calculated to confirm it is dramatically feasible and effective that the optimal WEN configuration can be gained by the proposed method.

关键词： Work exchange networks Transshipment model Adiabatic process Exergy analysis Isothermal process Work cascade

A novel joint navigation state error discriminator based on iterative maximum likelihood estimation

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Science China(Information Sciences) 2015年第12期58卷 119-132页

作者： WANG YongQing LUO yu WANG Pai WU SiLiang Department of Information and Electronics Beijing Institute of Technology

To break through the limitations of traditional discriminators used in vector tracking loops, this paper presents an iterative maximum likelihood estimation(IMLE) method for extracting navigation state errors from multi-satellite signals. The IMLE method takes into account both computational cost and estimation accuracy. The associated gradient vector and Hessian matrix of the MLE cost function are derived. The characteristics of the proposed joint discriminator are analyzed based on the properties of the MLE cost function,gradient vector, and Hessian matrix. The effectiveness of IMLE is verified by Monte Carlo simulation.

关键词： global navigation satellite system(GNSS) iterative maximum likelihood estimation(IMLE) joint navigation state error discriminator Cramer-Rao bound(CRB) vector tracking loop

Upper bounds on the capacity for optical intensity channels with AWGN

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Science China(Information Sciences) 2017年第2期60卷 165-176页

作者： Yingying yu Zaichen ZHANG Liang WU Jian DANG National Mobile Communications Research Laboratory Southeast University

The channel capacity of the optical wireless communication(OWC) systems is still a problem that has not an optimal and close-form expression, in spite of OWC can be used to achieve high data rates. This paper presents novel upper bounds on the channel capacity of an optical intensity modulated and directed detection(IM/DD) system under peak-power and average-power constraints. The channel is modeled as an additive white Gaussian noise(AWGN) optical channel. The bounds are derived based on sphere-based signal space argument. Simulation results show the proposed bounds are tight at both high and low signal-to-noise ratios(SNRs). Compared to those reported bounds, the derived bounds are better at high SNRs region in particular, and the expressions are simpler and unique for the whole range of average-to-peak-power ratio.

关键词： channel capacity optical communication AWGN sphere-based signal space high signal-to-noise ratios(SNRs)

In-situ Observation of Tensile Fracture in A357 Casting Alloys

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Journal of Materials Science & Technology 2014年第2期30卷 139-145页

作者： Zhongwei Chen Xiaolei Hao yu Wang Kai Zhao State Key Laboratory of Solidification Processing Northwestern Polytechnical University

The mechanism of damage evolution and fracture in A357 casting alloys was investigated by in-situ scanning electron microscopy （SEM） tensile testing. Different microstructures of A357 casting alloys were produced by eutectic Si modification and T6 heat treatment. It is shown that microcracks in these alloys are predominantly formed in eutectic Si particles. Large and elongated eutectic Si particles in unmodified alloy show the greater tendency to cracking, whereas cracking of small and round eutectic Si particles in Sr modified and T6 heat treated alloys is relatively lag. The crack mainly propagates along the broken eutectic Si particles in unmodified and Sr modified alloys or along the deepened shear bands in T6 heat treated alloy with accumulating the applied strain. The results were discussed in terms of Weibull statistics and the fracture models were established.

关键词： A357 casting alloy Eutectic silicon In-situ scanning electron microscopy (SEM) Fracture mechanism