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Limited Fraction of Crystallized Side Chains in Bottlebrush Poly(n-alkyl methacrylate)s

Chinese Journal of Polymer Science 2021年第9期39卷 1211-1216页

作者： Ming-Yue Xiang Dong Lyu Ling-Zhi Liu yong-feng Men State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefei 230026China

Crystallinity of bottlebrush polymers due to side chain crystallization has been considered to be related to the length of the side chains only under the assumption of complete participation of crystallization by all *** experimental results revealed that in poly(n-alkyl methacrylate)s a fraction of side chains could not crystallize due to constraints imposed by the trapped main chain entanglements and required expansi on of main chain-main chain *** result renders the original simplified con sideration of the origin of crystallinity in bottlebrush polymers *** this work,we introduce a new parameter f_(c),the fraction of crystallizable side chains,to better describe the crystallinity of bottlebrush polymers.A lin earrelati on ship between the meltingenthalpy and the number of alkyl groups in side chains for bottlebrush polymers reported repeatedly indicates that f_(c) remains essentially unchanged when bottlebrush polymers had the same main chain structure and grafting degree but different side chain *** slope of the above-mentioned linear relationship is thus △H_(CH2)xf_(c),where △H_(CH2) stands for the melting enthalpy of one mole alkyl group packed into the *** a known value of f_(c),it is possible to estimate the value of △H_(CH_(2)).In case of poly(n-alkyl methacrylate)s,we estimated △H_(CH_(2)) of hexagonal crystal being at most 5.74 kJ/mol with the knowledge of possibly smallest f_(c) of 0.67 obtained from small angle X-ray scattering ***,the crystallinity of bottlebrush polymer would be calculated based on the equati on X_(c)=f_(c)×N_(c)/N with N and N_(c) being the nu mber of alkyl groups in a side chain and those packed in the crystalline structure,*** chemical structure and grafting degree of bottlebrush polymers affect f_(c).

关键词： Poly(n-alkyl methacrylate)s(PMA(n)s) PMA(n)-co-PMMA Crystallization behavior The fraction of crystallizable side chain(fc) Grafting degree(G)

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Shared aperture metasurface antenna for electromagnetic vortices generation with different topological charges

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Chinese Physics B 2021年第8期30卷 337-344页

作者： He Wang yong-feng Li Shao-Bo Qu Department of Basic Sciences Air Force Engineering UniversityXi'an 710051China

Vortex beams carrying orbital angular momentum(OAM)have aroused great interest of both scientific and engineering ***,generating OAM with different topological charges in a shared aperture is regarded as a potential route to expanding the communication capacity,which yet is an academic challenging *** this work,a paradigm of designing metasurface-based shared aperture antenna for generating polarization-dependent vortex beams with distinct topological charges is *** unit cells that can tailor different resonance phase profiles in two orthogonal orientations are used to assemble a metasurface *** a proof-of-concept,a planar reflector antenna is designed with two Vivaldi sources,which can generate x-and y-polarized vortex beams with topological charges of l=-1 and l=-2,*** the simulation results and the measurement results are in good agreement,which demonstrates the feasibility of our ***,this work provides a new route to achieving vortex beams carrying different topological charges in the same frequency band,which may have potential applications in communication systems.

关键词： metasurface electromagnetic vortex antenna orbital angular momentum

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A review of physical supply and EROI of fossil fuels in China

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Petroleum Science 2017年第4期14卷 806-821页

作者： Jian-Liang Wang Jiang-Xuan feng yongmei Bentley Lian-yong feng Hui Qu School of Business Administration China University of PetroleumBeijing 102249China University of Bedfordshire Business School Luton LUI 3JUUK Petroleum Industry Press CNPCBeijing lO0011China

This paper reviews China’s future fossil fuel supply from the perspectives of physical output and net energy output. Comprehensive analyses of physical output of fossil fuels suggest that China’s total oil production will likely reach its peak, at about 230 Mt/year(or 9.6 EJ/year),in 2018; its total gas production will peak at around350 Bcm/year(or 13.6 EJ/year) in 2040, while coal production will peak at about 4400 Mt/year(or 91.9 EJ/year)around 2020 or so. In terms of the forecast production of these fuels, there are significant differences among current studies. These differences can be mainly explained by different ultimately recoverable resources assumptions, the nature of the models used, and differences in the historical production data. Due to the future constraints on fossil fuels production, a large gap is projected to grow between domestic supply and demand, which will need to be met by increasing imports. Net energy analyses show that both coal and oil and gas production show a steady declining trend of EROI(energy return on investment) due to the depletion of shallow-buried coal resources and conventional oil and gas resources, which is generally consistent with the approaching peaks of physical production of fossil fuels. The peaks of fossil fuels production, coupled with the decline in EROI ratios, are likely to challenge the sustainable development of Chinese society unless new abundant energy resources with high EROI values can be found.

关键词： Peak production Fossil fuels Net energy EROI China

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Influence of He ion irradiation on the microstructure and hardness of Ni-TiC_(NP)composites

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Nuclear Science and Techniques 2021年第11期32卷 32-41页

作者： Min Liu yong-feng Yan Zhen-Bo Zhu Lin-feng Ye Ren-Duo Liu He-Fei Huang Sino-French Institute of Nuclear Engineering and Technology Sun Yat-Sen UniversityZhuhai 519082China Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 100049China

In the present study,samples of a titanium carbide nanoparticle-reinforced nickel alloy(Ni-TiC_(NP)composite)were irradiated with 1 MeV He ions at 700°*** evolution of He bubbles and nanohardness was characterized using transmission electron microscopy(TEM)and nanoindentation,*** images showed that the size and number density of He bubbles in the grains were affected by the He ion *** number density first increased significantly and then decreased with increasing ion dose,while the size exhibited an inverse ***,the swelling induced by He bubbles continuously increased with increasing ion *** bubbles also formed in the grain boundaries,interior of the TiC nanoparticles,and interfaces between the TiC nanoparticles and Ni *** measurements indicated a decrease in nanohardness after irradiation,which is attributed to the disappearance of intrinsic dislocation lines caused by He ion irradiation.

关键词： Ni–TiC_(NP)composites He bubbles Swelling Irradiation-induced softening

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Detection of quantization index modulation steganography in G.723.1 bit stream based on quantization index sequence analysis

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Journal of Zhejiang University-Science C(Computers and Electronics) 2012年第8期13卷 624-634页

作者： Song-bin LI Huai-zhou TAO yong-feng HUANG Department of Electronic Engineering Tsinghua UniversityBeijing 100084China Tsinghua National Laboratory for Information Science and Technology Beijing 100084China

This paper presents a method to detect the quantization index modulation(QIM) steganography in G.723.1 bit *** show that the distribution of each quantization index(codeword) in the quantization index sequence has unbalanced and correlated *** present the designs of statistical models to extract the quantitative feature vectors of these *** the extracted vectors with the support vector machine,we build the classifier for detecting the QIM steganography in G.723.1 bit *** experiment shows that the method has far better performance than the existing blind detection method which extracts the feature vector in an uncompressed *** recall and precision of our method are all more than 90% even for a compressed bit stream duration as low as 3.6 s.

关键词： Steganalysis Quantization index modulation (QIM) G.723.1 Codeword distribution characteristics

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TLR3 gene polymorphisms in cancer:a systematic review and meta-analysis

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Chinese Journal of Cancer 2015年第6期34卷 8-20页

作者： Ben-Gang Wang De-Hui Yi yong-feng Liu Department 1 of General Surgery the First Affiliated Hospital of China Medical University

Introduction:Recent studies examining the association of Toll-like receptor 3(TLR3)gene polymorphisms with the risk of developing various types of cancer have reported conflicting *** this association could advance our knowledge of the influence of TLR3 single nucleotide polymorphisms(SNPs)on cancer ***:We systematically reviewed studies that focused on a collection of 12 SNPs located in the TLR3 gene and the details by which these SNPs influenced cancer ***,14 case-control studies comprising a total of7997 cases of cancer and 8699 controls were included in a meta-analysis of 4 highly studied SNPs(rs3775290,rs3775291,rs3775292,and rs5743312).Results:The variant TLR3 genotype rs5743312(C9948T,intron 3,C>T)was significantly associated with an increased cancer risk as compared with the wild-type allele(odds ratio[OR]=1.11,95%confidence interval[CI]=1.00–1.24,P=0.047).No such association was observed with other TLR3 *** the stratified analysis,the rs3775290(C13766T,C>T)variant genotype was found to be significantly associated with an increased cancer risk in Asian ***,the rs3775291(G13909A,G>A)variant genotype was significantly associated with an increased cancer risk in Asians,subgroup with hospital-based controls,and subgroup with a small sample ***:After data integration,our findings suggest that the TLR3 rs5743312 polymorphism may contribute to an increased cancer risk.

关键词：基因多态性癌症系统单核苷酸多态性 Toll样受体 SNPs 基因变异等位基因

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Continuous Full-Order Terminal Sliding Mode Control for a Class of Nonlinear Systems 36

Continuous Full-Order Terminal Sliding Mode Control for a Cl...

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第36届中国控制会议

作者： Minghao Zhou yong feng fengling Han Department of Electrical Engineering Harbin Institute of Technology School of Science RMIT University

ISBN: (纸本)9781538629185

Traditional sliding-mode control has two main problems,the singularity and chattering,which hinder its *** paper proposes a full-order terminal sliding mode control for a class of uncertain nonlinear systems to address these *** the ideal sliding motion,the nonlinear systems are forced to behave as a desirable full-order dynamics rather than a reduced-order *** output signals of the proposed controllers are continuous,which attenuates the *** singularity in the terminal sliding-mode control is avoided because the control strategies do not include the derivatives of fractional power *** effect of the measurement and calculation errors on the systems is *** simulation results validate the proposed method.

关键词： Sliding-mode control terminal sliding-mode control finite-time convergence singularity Lyapunov stability

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BO_(2)-F^(+)Centers in the Radiation-damaged YCOB Crystals

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Chinese Physics Letters 2000年第12期17卷 896-898页

作者： RUAN yong-feng Hiroshi NAKAO Takatomo SASAKI Department of Physics Tianjin UniversityTianjin 300072 Department of Electrical Engineering Osaka UniversityOsaka 565-0871Japan

An intense paramagnetic EPR signal generated from x-ray-irradiated,powdered YCOB crystals was observed at the liquid nitrogen temperature for the first *** peaks,located at the positions where the effective g factor equals to 1.992,1.986,1.980,1.974 and 1.965,labeled as A,B,C,D and E respectively,were *** is believed that the peaks A,B,C and D generated from the BO_(2)-F^(+)center which is a single electron trapped in an oxygen vacancy which was originally occupied by an O^(2-)ion bonded to a(BO3)^(3-)anion *** peak E is thought of coming from Y2+ions that are formed by the Y^(3+) ions trapping *** mechanism for the formation of the radiation-induced defects in the YCOB crystals is suggested.

关键词： Crystal occupied trapping

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Confluence and cold shut computation based on time field in casting simulation

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China Foundry 2021年第2期18卷 101-109页

作者： yong-shuai feng Dun-ming Liao Tao Chen State Key Laboratory of Materials Processing ami Die&Mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China Wuhan Chenxi Yunfeng Technology Co. Ltd.Wuhan 430074China

Numerical simulation technology has been widely used in the foundry industry to analyze and improve casting *** the casting filling process,many filling-related defects form easily at the confluences of liquid metal *** main filling-related defects are cold shut *** calculate the positions of casting defects,the characteristics of liquid metal confluences were *** flow front of liquid metal was captured by the volume-of-fluid algorithm to obtain a time field,which was used to calculate the time derivatives of the liquid front position and the confluences of liquid metal *** distinguish small confluences from the main confluences,the concept of confluent scale was developed,which was used to filter the small confluences based on a *** calculation process was demonstrated through the post-processing of numerical simulation.A "W" shaped casting and a steering wheel casting were calculated to validate the accuracy of the method developed in this *** positions of cold shut defects were predicted by calculating the confluences of liquid metal *** method was proved to be practical by comparing the calculation results with the positions of cold shut defects in an end cover *** computation of confluences and cold shut defects can improve the analysis efficiency and provide assurance for the optimization of a casting process plan.

关键词： numerical simulation casting defects flow front time field confluence cold shut

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High-Order Sliding-Mode based Energy Saving Control of Induction Motor

High-Order Sliding-Mode based Energy Saving Control of Induc...

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第25届中国控制与决策会议

作者： yong feng Minghao Zhou Xinghuo Yu Harbin Institute of Technology RMIT University

ISBN: (纸本)9781467355322

This paper proposes a high-order sliding-mode control method for grid-connected converter of an induction motor （IM） system, implementing the regenerative energy feedback with high quality and achieving the energy-saving operation of an IM system. A nonsingular terminal sliding-mode manifold is designed for the two current controllers and the related control strategies are applied to stabilize the whole motor system. The designed high-order sliding-mode control laws guarantee the strong robustness of the motor system. In addition, the chattering phenomenon in the sliding-mode control based motor system is eliminated effectively. The simulation results validate the proposed method.

关键词： Sliding-Mode Control Induction Motors Energy Saving

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