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Virtual Reality:A State-of-the-Art Survey

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International Journal of Automation and computing 2009年第4期6卷 319-325页

作者： ning-ning zhou Yu-Long Deng School of Computing Nanjing University of Posts and Telecommunications Nanjing 210003 PRC State Key Laboratory of Software Development Environment Beihang University Beijing 100191 PRC

This paper presents a survey on virtual reality systems and provides an in-depth understanding toward the notion of immersion, according to the semantic meanings of the terms ＂virtual＂ and ＂reality＂. The paper analyses the structure and functions of a virtual reality system and takes the three dimensional display as the immersive medium to identify the key issues for construction of virtual environments. The paper also reviews the development of virtual reality technology and introduces new image processing techniques into the design of virtual reality systems and virtual environments.

关键词： Virtual reality immersion virtual reality image processing technology

Molecular basis for the selective recognition and ubiquitination of centromeric histone H3 by yeast E3 ligase Psh1

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Journal of Genetics and Genomics 2021年第6期48卷 463-472页

作者： ning zhou Liuxin Shi Shan Shan Zheng zhou National Laboratory of Biomacromolecules CAS Center for Excellence in BiomacromoleculesInstitute of BiophysicsChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100089China

Centromeres are chromosomal loci marked by histone variant Cen H3(centromeric histone H3)and essential for genomic stability and cell *** budding yeast E3 ubiquitin ligase Psh1 selectively recognizes the yeast Cen H3(Cse4)for ubiquitination and controls the cellular level of Cse4 for proteolysis,but the underlying mechanism remains largely ***,we show that Psh1 uses a Cse4-binding domain(CBD,residues 1-211)to interact with Cse4-H4 instead of H3-H4,yielding a dissociation constant(Kd)of 27 ***1 recognizes Cse4-specific residues in the L1 loop and a2 helix to ensure Cse4 binding and *** map the Psh1-binding region of Cse4-H4 and identify a wide range of Cse4-specific residues required for the Psh1-mediated Cse4 recognition and *** analyses reveal that histone chaperone Scm3 can impair Cse4 ubiquitination by abrogating Psh1-Cse4 ***,our study reveals a novel Cse4-binding mode distinct from those of known Cen H3 chaperones and elucidates the mechanism by which Scm3 competes with Psh1 for Cse4 binding.

关键词： Cse4 CENP-A Psh1 Scm3 Selective recognition Ubiquitination

Step-by-Step Numerical Prediction of Aerodynamic Noise Generated by High Speed Trains

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Chinese Journal of Mechanical Engineering 2022年第2期35卷 251-264页

作者： Tian Li Deng Qin ning zhou Weihua Zhang State Key Laboratory of Traction Power Southwest Jiaotong UniversityChengdu 610031China

In this paper,the unsteady flow around a high-speed train is numerically simulated by detached eddy simulation method(DES),and the far-field noise is predicted using the Ffowcs Williams-Hawkings(FW-H)acoustic *** reliability of the numerical calculation is verified by wind tunnel *** superposition relationship between the far-field radiated noise of the local aerodynamic noise sources of the high-speed train and the whole noise source is *** the aerodynamic noise of high-speed trains is derived from its different components,a stepwise calculation method is proposed to predict the aerodynamic noise of high-speed *** results show that the local noise sources of high-speed trains and the whole noise source conform to the principle of sound source energy *** the head,middle and tail cars of the high-speed train as noise sources,different numerical models are established to obtain the far-field radiated noise of each aerodynamic noise *** far-field total noise of high-speed trains is predicted using sound source superposition.A step-by-step calculation of each local aerodynamic noise source is used to obtain the superimposed value of the far-field *** is consistent with the far-field noise of the whole train model’s aerodynamic *** averaged sound pressure level of the far-field longitudinal noise measurement points differs by 1.92 *** step-by-step numerical prediction method of aerodynamic noise of high-speed trains can provide a reference for the numerical prediction of aerodynamic noise generated by long marshalling high-speed trains.

关键词： High-speed train Aerodynamic noise Sound source superposition Numerical prediction

Lightweight quasi-layered elastic fibrous porous ceramics with high compressive stress and low thermal conductivity

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Journal of Materials Science & Technology 2023年第12期143卷 207-215页

作者： ning zhou Baosheng Xu Zhiliang zhou Lijie Qu Yiguang Wang Wenbo Han Daining Fang National Key Laboratory of Science and Technology for National Defense on Advanced Composites in Special Environments Harbin Institute of TechnologyHarbin 150001China Institute of Advanced Structure Technology Beijing Institute of TechnologyBeijing 100081China

Fibrous porous ceramics are attractive for use as thermal insulation ***,the intrinsic brit-tleness of rigid materials has remained challenging and severely restricts their ***,we demonstrated a facile method for fabricating elastic fibrous porous ceramics(EFPCs)with high com-pressive strength and low thermal conductivity through ordinary press filtration and subsequent heat *** quasi-layered structure and the well-bonded bridging fibers between layers are the key points for the elasticity of *** advanced EFPCs exhibited low density(∼0.126 g cm^(−3)),high com-pressive stress(∼0.356 MPa),and low thermal conductivity(∼0.026 W m^(−1) K^(−1)).Compared with rigid porous fibrous materials,the EFPCs had deformability and excellent shape *** contrast to flexible materials,the EFPCs possessed high compressive stress,thus endowing them with good resistance to *** emergence of this fascinating material may provide new insights for candidate materials in thermal insulation and other fields.

关键词： Silica fiber Facile press filtration Elastic fibrous porous ceramics High compressive stress Thermal insulation

Infrared emissivity and microwave absorbing property of epoxy-polyurethane/annealed carbonyl iron composites coatings

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Science China(Technological Sciences) 2012年第3期55卷 623-628页

作者： CHEN YanPeng XU GuoYue GUO TengChao zhou ning College of Material Science and Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

The microwave absorption property and infrared emissivity have been investigated for the single-layer coating made of the epoxy-polyurethane resin and carbonyl iron powders with variation of annealing treatment. Microwave-absorbing property was investigated by measuring the complex permittivity and complex permeability of the absorber in the frequency range from 2 to 18 GHz. Infrared emissivity value was measured using IR-2 Infrared Emissometer in the wavelength range of 8-14 μm. After annealing, the Fe （110） peak became sharp, and the crystallization improved significantly. Annealing treatment could reduce the sttrface energy of powders, improve compatibility between fillers and adhesives, and result in increase of the density of the coating. The lowest value of infrared emissivity （0.419） was obtained from the coating made of the carbonyl iron powder annealed at 700℃ for 1 h. With the variation of the annealing temperature, the magnetic and dielectric properties of the carbonyl iron particle were changed. The maximum reflection loss decreased and the matching frequency shifted to lower frequency with increasing the annealing temperature of carbonyl iron particles, which coincided with the variation of the complex permeability and permittivity according to the annealing temperature. Magnetic loss factor and dielectric loss factor of carbonyl iron particles were improved with increasing the annealing temperature in the 2-18 GHz range.

关键词： carbonyl iron infrared emissivity microwave absorbing property annealing treatment

Effect of solvent on the initiation mechanism of living anionic polymerization of styrene:A computational study

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Chinese Journal of Chemical Engineering 2024年第5期69卷 135-142页

作者： Shen Li Yin-ning zhou Zhong-Xin Liu Zheng-Hong Luo School of Chemical Engineering and Technology Hainan UniversityHaikou 570228China Department of Chemical Engineering School of Chemistry and Chemical EngineeringState Key Laboratory of Metal Matrix CompositesShanghai Jiao Tong UniversityShanghai 200240China

For living anionic polymerization(LAP),solvent has a great influence on both reaction mechanism and *** this work,by using the classical butyl lithium-styrene polymerization as a model system,the effect of solvent on the mechanism and kinetics of LAP was revealed through a strategy combining density functional theory(DFT)calculations and kinetic *** terms of mechanism,it is found that the stronger the solvent polarity,the more electrons transfer from initiator to solvent through detailed energy decomposition analysis of electrostatic interactions between initiator and solvent ***,we also found that the stronger the solvent polarity,the higher the monomer initiation energy barrier and the smaller the initiation rate ***,initiation is more favorable at lower temperatures based on the calculated results ofΔG_(TS).Finally,the kinetic characteristics in different solvents were further examined by kinetic *** is found that in benzene and n-pentane,the polymerization rate exhibits first-order ***,slow initiation and fast propagation were observed in tetrahydrofuran(THF)due to the slow free ion formation rate,leading to a deviation from first-order kinetics.

关键词： Living anionic polymerization Solvent effect Reaction kinetics Computational chemistry Mathematical modeling Kinetic modeling

Investigation and numerical simulation of inner-flow of an axial mineflow fan under low flow rate conditions

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Journal of China University of Mining and Technology 2008年第1期18卷 107-111页

作者： LI Yi-min zhou Zhong-ning School of Mechanical and Electrical Engineering China University of Mining ＆ Technology Xuzhou Jiangsu 221008 China

Because of unstable properties of axial mine flow fans working under conditions of low flow rates, the safety and reliability of fans in their operational zone is reduced. At times, serious vibration may bring about the destruction of equipment or even jeopardize the safety of entire factories. By means of oil flow visualization techniques and numerical simulation, we have investigated the inner-flow of an axial mine flow fan working under low flow rate conditions. The fundamental reasons of complex flow phenomena of the inner-flow of the flow fan under these stated conditions were revealed. At the same time and in order to improve the inner-flow under conditions of low flow rates, a blade separator and air separator were designed. From our tests we found that the blade separator and air separator are two kinds efficient methods to improve the unstable working characteristics of the axial mine flow fan operating under low flow rate conditions. The effect of the improvement of the air separator is stronger than that of the blade separator.

关键词： numerical simulation inner-flow low flow rate

Transport of intensity diffraction tomography with non-interferometric synthetic aperture for three-dimensional label-free microscopy

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Light(Science & Applications) 2022年第10期11卷 2294-2307页

作者： Jiaji Li ning zhou Jiasong Sun Shun zhou Zhidong Bai Linpeng Lu Qian Chen Chao Zuo School of Electronic and Optical Engineering Nanjing University of Science and TechnologyNo.200 Xiaolingwei StreetNanjingJiangsu Province 210094China Jiangsu Key Laboratory of Spectral Imaging&Intelligent Sense Nanjing University of Science and TechnologyNanjingJiangsu Province 210094China Smart Computational Imaging Laboratory(SCILab) Nanjing University of Science and TechnologyNanjingJiangsu Province 210094China

We present a new label-free three-dimensional(3D)microscopy technique,termed transport of intensity diffraction tomography with non-interferometric synthetic aperture(TIDT-NSA).Without resorting to interferometric detection,TIDT-NSA retrieves the 3D refractive index(RI)distribution of biological specimens from 3D intensity-only measurements at various illumination angles,allowing incoherent-diffraction-limited quantitative 3D phase-contrast *** unique combination of z-scanning the sample with illumination angle diversity in TIDT-NSA provides strong defocus phase contrast and better optical sectioning capabilities suitable for high-resolution tomography of thick biological *** on an off-the-shelf bright-field microscope with a programmable light-emitting-diode(LED)illumination source,TIDT-NSA achieves an imaging resolution of 206 nm laterally and 520 nm axially with a high-NA oil immersion *** validate the 3D RI tomographic imaging performance on various unlabeled fixed and live samples,including human breast cancer cell lines MCF-7,human hepatocyte carcinoma cell lines HepG2,mouse macrophage cell lines RAW 264.7,Caenorhabditis elegans(***),and live Henrietta Lacks(HeLa)*** results establish TIDT-NSA as a new non-interferometric approach to optical diffraction tomography and 3D label-free microscopy,permitting quantitative characterization of cell morphology and time-dependent subcellular changes for widespread biological and medical applications.

关键词： illumination intensity synthetic

Formation of composite hydrogel of carboxymethyl konjac glucomannan/gelatin for sustained release of EGCG

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Food Science and Human Wellness 2022年第5期11卷 1373-1383页

作者： Lin Wang ning zhou Shengxuan Zheng Jie Pang Department of Engineering Mechanics Tsinghua UniversityBeijing 100084China Institute of Superlubricity Technology Research Institute of Tsinghua University in ShenzhenShenzhen 518057China College of Food Science Fujian Agriculture and Forestry UniversityFuzhou 350002China

Development of functional bioinspired hydrogels that have good releases control character is necessary for the application of these materials in biomedical ***,we report a composite hydrogel prepared from several biocompatible carboxymethyl konjac glucomannan(CKGM)/gelatin(G)/tannic acid(TA)functional nano-hydroxyapatite(TA@n-HA),which has good biodegradability and pH *** mechanism of interaction between hydrogels was confirmed by Fourier transform infrared spectroscopy,X-ray diffraction,Scanning electron microscopy and Thermogravimetric *** physico-chemical properties of CKGM/G hydrogels have been significantly improved through the incorporation of TA@n-HA within the *** in the sustained release of epigallocatechin gallate(EGCG)demonstrated that the TA@n-HA/CKGM/G hydrogels exhibit not only better pH sensitive properties,but also enhanced biocompatibility and encapsulation in comparison to the matrix devoid of TA@***,TA@n-HA/CKGM/G hydrogels using EGCG as a drug release model show the potential for drug delivery.

关键词： Hydrogel Carboxymethyl konjac glucomannan Gelatin Tannic acid Biodegradation Sustained release

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