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Theoretical Analysis and Numerical Simulation of the Static and Dynamic Characteristics of Hydrostatic Guides Based on Progressive Mengen Flow Controller

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Chinese Journal of Mechanical Engineering 2010年第6期23卷 709-716页

作者： GAO Dianrong zheng dan ZHANG Zuochao Key Laboratory of Heavy Machinery Fluid Power Transmission and Control of Hebei Province Yanshan University Qinhuangdao 066004 China

The oil film thickness of oil hydrostatic guide with constant pressure supply based on capillary restrictor is greatly affected by load, and this kind of hydrostatic guide is usually applied to the machine tools with moderate load. The static and dynamic characteristics of the guide have been studied by using some theoretical, numerical and experimental approaches, and some methods and measures have been proposed to improve its performances. The hydrostatic guide based on progressive mengen（PM） flow controller is especially suitable for the heavy numerical control（NC） machine tools. However, few literatures about the research on the static and dynamic characteristics of the hydrostatic guides based on PM flow controller are reported. In this paper, the formulae are derived for analyzing the static and dynamic characteristics of hydrostatic guides with rectangle pockets and PM flow controller according to the theory of hydrostatic bearing. On the basis of the analysis of hydrostatic bearing with circular pocket, some equations are derived for solving the static pressure, volume pressure and squeezing pressure which influence the dynamic characteristics of hydrostatic guides with rectangle pocket. The function and the influencing factors of three pressures are clarified. The formulae of amplitude-frequency characteristics and dynamic stiffness of the hydrostatic guide system are derived. With the help of software MATLAB, programs are coded with C＋＋ language to simulate numerically the static and dynamic characteristics of the hydrostatic guide based on PM flow controller. The simulation results indicate that the sensitive oil volume between the outlet of the PM flow controller and the guide pocket has the greatest influence on the characteristics of the guide, and it should be reduced as small as possible when the field working condition is met. Choosing the oil with a greater viscosity is also helpful in improving the dynamic performance of hydrostatic guides. The re

关键词： PM flow controller rectangle pocket static characteristics dynamic characteristics hydrostatic guides

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Influence of Fe on Microstructure and Mechanical Properties in Pdoped Ni–Cr–Fe Alloys

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Acta Metallurgica Sinica(English Letters) 2019年第6期32卷 771-779页

作者： Xin-Tong Lian Wen-Ru Sun Xin Xin Fang Liu dan-dan zheng Institute of Metal Research Chinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering Shanghai UniversityShanghai 200444China

The influence of Fe on the microstructure and mechanical properties of P-doped Ni–Cr–Fe alloys has been *** showed that increasing Fe content refined the dendrite microstructure and enhanced the solubility of P in as-cast *** change of microhardness in different dendrite regions was attributed to the segregation of P atoms in solid solution state,which had strengthening *** Fe contents from 15.2 to 60.7 wt%reduced the yield strength and tensile strength but had little influence on the elongation of *** stress rupture life of alloys after heat treatment decreased with the increment of Fe contents,and the failure fracture modes transferred from transgranular to intergranular fracture *** change of fracture modes was due to the weakness of grain boundaries caused by the increment of *** addition,the precipitation of M23C6 was believed to be related to the segregation of P toward grain boundaries,which led to the fluctuation of carbon and chromium atoms near the grain boundaries in alloys with low Fe ***,the increment of Fe decreased the strength of matrix and changed the existence of P atoms and the precipitates at grain boundaries.

关键词： Fe P Segregation Precipitate Mechanical properties

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Effects of Phosphorus and Iron on Microstructures and Mechanical Properties in NiCrFe-Based Alloys

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Acta Metallurgica Sinica(English Letters) 2019年第5期32卷 659-667页

作者： Xin-Tong Lian Wen-Ru Sun Fang Liu dan-dan zheng Xin Xin Institute of Metal Research Chinese Academy of Sciences School of Materials Science and Engineering University of Science and Technology of China

The microstructures and mechanical properties, especially creep properties, of the NiCrFe-based alloys with various contents of phosphorus and iron were investigated. The results showed that the tensile yield strength decreased with increasing iron contents while had no obvious change with the addition of phosphorus. For creep properties, the alloy with15.8 wt% iron and 0.09 wt% phosphorus possessed the longest creep life(679 h) among all alloys. Only M_(23)C_6 was formed in the alloys with low phosphorus contents, while both intergranular M_3P and M_(23)C_6 precipitated with the increment of phosphorus, which enhanced the strength of grain boundary by hindering the movements of dislocations during creep tests. The reasons for the enhancement of creep life were mainly related to the solid solution strengthening effect of phosphorus and optimization of grain boundary precipitations by phosphorus.

关键词： NiCrFe-based alloys Phosphorus Iron Microstructures Creep properties

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Absolute control of helicity at the C-termini in quinoline oligoamide foldamers by chiral oxazolylaniline moieties

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Chinese Chemical Letters 2020年第3期31卷 673-676页

作者： dan zheng Chengyuan Yu Lu zheng Yulin Zhan Hua Jiang Department of Chemistry Beijing Normal UniversityBeijing 100875China

Absolute one-handed chiral quinoline tetramers andoctamers containing different oxazolylanilines at the C-terminus have been *** absolute one-handed sense and diastereomeric excess values were valued by^1H NMR.X-ray crystal diffractionand CD studies reveal that the S-oxazolylaniline always induces a P-handed helicity and the absolute helicity is driven by the stable three-center hydrogen bonding between protons in the amide and N atoms in oxazolylaniline and adjacent quinoline *** investigations demonstrated that S-CQn-a-d are CPL active and its g(lum)values are dependent on its ***,the sizes of the substituents in the chiral centers are different,howeve r,they exert no effect on the dissymmetric factors g(abs)and g(lum)of quinoline oligoamide foldamers.

关键词： Chiral induction Helical chirality Aromatic foldamer Circularly polarized luminescence Three-center hydrogen bonding

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Entanglement teleportation via a couple of quantum channels in Ising–Heisenberg spin chain model of a heterotrimetallic Fe–Mn–Cu coordination polymer

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Chinese Physics B 2019年第12期28卷 105-112页

作者： Yi-dan zheng Zhu Mao Bin Zhou Department of Physics Hubei UniversityWuhan 430062China

We investigate the teleportation of an entangled state via a couple of quantum channels, which are composed of a spin-1/2 Heisenberg dimer in two infinite Ising–Heisenberg chains. The heterotrimetallic coordination polymer CuⅡMnⅡ(L1)][FeⅢ(bpb)(CN)2]·ClO4·H2O(abbreviated as Fe–Mn–Cu) can be regarded as an actual material for this *** apply the transfer-matrix approach to obtain the density operator for the Heisenberg dimer and use the standard teleportation protocol to derive the analytical expression of the density matrix of the output state and the average fidelity of the entanglement teleportation. We study the effects of the temperature T, anisotropy coupling parameter △, Heisenberg coupling parameter J2 and external magnetic field h on the quantum channels. The results show that anisotropy coupling? and Heisenberg coupling J2 can favor the generation of the output concurrence and expand the scope of the successful average fidelity.

关键词： entanglement teleportation Ising–Heisenberg chain transfer-matrix approach concurrence

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A semi-custom design methodology for design performance optimization

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第4期9卷 510-516页

作者： Dong-ming LV Pei-yong ZHANG dan-dan zheng Xiao-lang YAN Bo ZHANG Li QUAN Institute of VLSI Design Zhejiang University Hangzhou 310027 China

We present a semi-custom design methodology based on transistor tuning to optimize the design performance. Compared with other transistor tuning approaches, our tuning process takes the cross-talk effect into account and prominently reduces the complexity for circuit simulation and analysis by decomposing the circuit network utilizing graph theory. Furthermore, the incremental placement and routing for the corresponding transistor tuning in conventional approaches is not required in our methodology, which might induce timing graph variation and additional iterations for design convergence. This methodology combines the flexible automated circuit tuning and physical design tools to provide more opportunities for design optimization throughout the design cycle.

关键词： Transistor tuning Cross-talk Circuit decomposing

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Species Composition and Diversity of Macrobenthos in the Intertidal Zone of Xiangshan Bay,China

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Journal of Ocean University of China 2015年第2期14卷 375-384页

作者： JIAO Haifeng zheng dan YOU Zhongjie XU Nianjun LOU dan HUANG Chengwei School of Marine Science Ningbo University Ningbo Academy of Oceanology and Fishery

Xiangshan bay is a narrow semi-closed bay and situated on the northwestern coast of the East China Sea. Over past decades, it has become to a major bay with intensive human activities, dense urbanized area, and poor water quality. The aim of this paper was to reveal the ecological status through the elucidation of the species composition, abundance, biomass and diversity of macrobenthos in this bay. Six intertidal sections were surveyed from January 2007 to November 2008 quarterly. Sections TG, HD and XH are located in the three inner bays, sections QJ and WS are located near the thermal power plants, and section XX is located at the outer part of Xiangshan Bay. Great variations in macrobenthos community were indentified, and the species composition of the community in the present study showed the dominance in the order of molluscs （bivalves and gastropods）, crustaceans and others, and only few Polychaeta were recorded. Only three dominant species, Littorina brevicula, llyplax tansuiensis, and Cerithidea cingu- lata were collected in all the sections, and a total of 19 dominant species were recorded only in one section. Two-way ANOVA analyses of abundance indicated that there were significant differences among sections or seasons. Shannon-Wiener diversity index （H＇） had its maximum （2.45） in section QJ, and minimum （1.76） in section TG Multiple irregular k-dominance plots clearly showed that the study area was polluted and the macrobenthos community was under stress. We conclude that the macrobenthos of Xiang- shan Bay have been disturbed by human activities, especially at the interior bay.

关键词： macrobenthos abundance biomass community structure species diversity intertidal zone

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Etiology and management of liver injury in patients with COVID-19

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World Journal of Gastroenterology 2020年第32期26卷 4753-4762页

作者： Rui-Xu Yang Rui-dan zheng Jian-Gao Fan Center for Fatty Liver Department of GastroenterologyXinhua Hospital Affiliated to Shanghai Jiao Tong University School of MedicineShanghai 200092China Diagnosis and Treatment Center for Liver Diseases Zhengxing HospitalZhangzhou 363000Fujian ProvinceChina Center for Fatty Liver Department of GastroenterologyXinhua Hospital Affiliated to Shanghai Jiao Tong University School of MedicineShanghai Key Lab of Pediatric Gastroenterology and NutritionShanghai 200092China

The outbreak of novel coronavirus disease 2019(COVID-19)has resulted in global *** the expansion of related research,in addition to respiratory symptoms,digestive system involvement such as nausea,vomiting,and diarrhea have also been reported with ***,abnormal liver function is also frequent in biochemical tests of COVID-19 patients,which is correlated with the severity and mortality of the disease *** etiology of liver injury in patients with COVID-19 might include viral immunologic injury,drug-induced liver injury,the systemic inflammatory response,hypoxic hepatitis,and the exacerbation of preexisting liver *** liver injuries in COVID-19 are often transient and reversible,health workers need to pay attention to preexisting liver disease,monitor liver function,strengthen supportive treatment,and reduce the chance of drug-induced liver *** article reviews the epidemiological characteristics,etiology,management,and preventive strategies for liver injury in patients with COVID-19.

关键词： COVID-19 SARS-CoV-2 Coronavirus Liver injury Function test,Liver Etiology

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A quadruple helicene with a rubicene core: synthesis, structural analyses and properties

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Science China Chemistry 2021年第4期64卷 590-598页

作者： Qi Xu Chu Wang dan zheng Ying Wang Xuebo Chen Di Sun Hua Jiang College of Chemistry Beijing Normal UniversityBeijing 100875China School of Chemistry and Chemical Engineering Shandong UniversityJinan 250100China

We report the synthesis of a quadruple helicene with a rubicene core R1 by a Scholl *** the 10 stereoisomers including 4 pairs of enantiomers and 2 meso isomers,only 2 pairs of enantiomers and 1 meso isomer have been *** sample structures were unambiguously determined by X-ray crystallography to be(P,P)_(6)-(P,P)_(5)/(M,M)_(6)-(M,M)_(5)-R1-A,which has a propeller-shaped structure,and(M,M)_(6)-(P,P)_(5)/(P,P)_(6)-(M,M)_(5)-R1-B and(M,P)_(6)-(P,M)_(5)-R1-C,which have saddle-shaped *** chiral resolutions of R1 were carried out by chiral HPLC,revealing two pairs of chiral stereoisomers(P,P)_(6)-(P,P)_(5)/(P,P)_(6)-(M,M)_(5),(M,M)_(6)-(P,P)_(5)/(M,M)_(6)-(M,M)_(5) as well as a meso isomer(M,P)_(6)-(P,M)_(5),which were further characterized by CD spectroscopy and time-dependent density functional theory(TD-DFT)***,the UV-vis absorption and emission spectra of these resolved stereoisomers and unresolved R1 were almost *** addition,the chemical oxidation of R1 led to the formation of radical cations and dications at room temperature.

关键词： quadruple helicene rubicene stereoisomer dynamic behaviors

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Formation mechanism of inherent spatial heterogeneity of microstructure and mechanical properties of NiTi SMA prepared by laser directed energy deposition

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International Journal of Extreme Manufacturing 2023年第3期5卷 548-567页

作者： MengJie Luo Ruidi Li dan zheng JingTao Kang HuiTing Wu ShengHua Deng PengDa Niu State Key Laboratory of Powder Metallurgy Central South UniversityChangshaHunan 410083People’s Republic of China Faculty of Materials Metallurgy and Chemistry Jiangxi University of Science and TechnologyGanzhou 341000People’s Republic of China

Ni51Ti49 at.%bulk was additively manufactured by laser-directed energy deposition(DED)to reveal the microstructure evolution,phase distribution,and mechanical *** is found that the localized remelting,reheating,and heat accumulation during DED leads to the spatial heterogeneous distribution of columnar crystal and equiaxed crystal,a gradient distribution of Ni4Ti3 precipitates along the building direction,and preferential formation of Ni4Ti3 precipitates in the columnar *** austenite transformation finish temperature(Af)varies from-12.65℃(Z=33 mm)to 60.35℃(Z=10 mm),corresponding to tensile yield strength(σ0.2)changed from 120±30 MPa to 570±20 MPa,and functional properties changed from shape memory effect to superelasticity at room *** sample in the Z=20.4 mm height has the best plasticity of 9.6%and the best recoverable strain of 4.2%.This work provided insights and guidelines for the spatial characterization of DEDed NiTi.

关键词： shape memory alloy gradient functional materials laser directed energy deposition spatial heterogeneity additive manufacturing mechanical properties

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