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Communications in Theoretical Physics 2001年第11期36卷 513-518页

作者： yan zhen-Ya Department of Applied Mathematics Dalian University of TechnologyDalian 116024China

In this paper,eight types of (1-+1)-dimensional similarity reductions which contain variable coefficient equation,are obtained for the generalized KdV equation in (2+1)-dimensional space arising from the multidimensional isospectral flows associated with the second-order scalar operators by using the direct *** addition,the cnoidal wave solution and dromion-like solution are also derived by using the reduced nonlinear ordinary differential *** (1+1) dromion obtained by Lou [***.A28 (1995) 7227] and Zhang [***.9 (2000) 1] is only a special case of our ***,some properties of the dromion-like solutions are analyzed.

关键词： generalized KdV equation,similarity reduction,Painlevé-I equation,Painlevé-II equation,cnoidal waves,dromion-like solution

Differential Approximation Algorithm of FSMVRP

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Acta Mathematicae Applicatae Sinica 2015年第4期31卷 1091-1102页

作者： Yu-zhen HU Bao-guang XU Institute of Policy and Management Chinese Academy of Sciences School of Economics and Management Harbin Engineering University

Abstract We study the fleet size and mix vehicle routing problem with constraints on the capacity of each vehicle. The objective is to minimize the total cost including fixed utilization cost of vehicles and traveling cost by vehicles. We give differential approximation algorithms for the fleet size and mix vehicle routing problem （FSMVRP） with two kinds of vehicles, the capacities of which are respectively nlk and n2k, n2 〉 nl ≥ 1, k ≥ 1. Using existing theories for vehicle routing problems and feature of the algorithms represented in the paper, we also prove that the algorithms give（1-6n＋3/（n＋1）2k＋n＋1）differential approximation ratio for （k, nk） VRP, n 〉 1and （1-6n2＋3n/n1k＋n2k）2k）differential approximation ratio for （nlk, n2k）VRP, n2 〉 nl 〉 1.

关键词： FSMVRP differential approximation ratio approximation algorithm

Development of new ductile iron with super-high thermal conductivity and elongation

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Journal of Iron and Steel Research International 2022年第3期29卷 462-473页

作者： guang-hua Wang yan-xiang Li School of Materials Science and Engineering Tsinghua UniversityBeijing100084China Key Laboratory for Advanced Materials Processing Technology Ministry of EducationBeijing100084China

The effects of Si content,graphite volume fraction and pearlite volume fraction on the thermal conductivity of ductile iron were studied based on theoretical model *** results showed that the thermal conductivity of ductile iron was more sensitive to Si content compared with the volume fractions of pearlite and *** key method to design and develop high thermal conductivity ductile iron was to control the Si *** 0.9-2.2 wt.%Si content,experimental results showed that with the increase in Si content,the thermal conductivity of ductile iron decreased dramatically,and the yield strength and tensile strength of ductile iron almost linearly increased,but the elongation remained almost *** dependence of thermal conductivity of ductile iron on temperature changed from monotonic decreasing to increasing first and then ***,we broke the common composition range of ductile iron and designed a new high C(≥3.9 wt.%)and low Si(1.0-1.4 wt.%)ductile iron with super-high thermal conductivity and *** thermal conductivity exceeded 40 W/(m K)within 27-300℃,and maintained at 35-40 W/(m K)at 500℃.The elongation was over 25%,and the tensile strength was more than 300 MPa.

关键词： Thermal conductivity Ductile iron Elongation Tensile strength Silicon alloying

Petrogenesis and Tectonic Implications of A-type Granites in Zhaheba in the East Junggar Region of Xinjiang,China:Evidence from Geochronology,Geochemistry and Sr-Nd Isotopic Compositions

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Acta Geologica Sinica(English Edition) 2022年第3期96卷 938-953页

作者： TANG Hejun MENG Guixiang WU zhenhan WANG Zhaolin DENG zhen yan Jiayong QI guang XUE Ronghui Chinese Academy of Geological Sciences China Geological SurveyMinistry of Natural ResourcesBeijing 100037China SinoProbe Center Chinese Academy of Geological SciencesChina Geological SurveyMinistry of Natural ResourcesBeijing 100037China

The magma source,petrogenesis,tectonic setting and geochronology of the late Paleozoic A-type granites widely exposed in the Zhaheba area,East Junggar,have thus far not been well-constrained.A better understanding of these issues will help to reveal the magmatic processes and continental growth of Central *** A-type granites in Zhaheba include the Ashutasi alkaline granites and the Yuyitasi syenogranites,which were emplaced at 321.5±4.8 Ma and 321.7±0.6 Ma,*** major rock-forming minerals are orthoclase,perthite,arfvedsonite and quartz,which exhibit the following principal geochemical characteristics of A2-type granites.(1)Their REE distribution curves each exhibit a‘V’-shaped pattern and a marked depletion in *** are rich in large-ion lithophile elements Rb,Th and U as well as high-field-strength elements Nb,Ta,Zr and Hf,but significantly depleted in Ba,Sr,P and Ti.(2)Their(^(87)Sr/^(86)Sr)i values(0.7021-0.7041),εNd(t)values(4.57-5.16)and REE distribution patterns are in basic agreement with those of the Kalamaili A-type granite belt in East *** T DM2 values of the alkaline granites and syenogranites range from 661 to 709 *** A-type granites may be the products of upwelling asthenosphere-triggered partial melting of immature lower *** alkaline granites were late-stage products of crystallization and *** to the syenogranites,the alkaline granites are significantly lower in K_(2)O,Na_(2)O,Al_(2)O 3,FeO,MgO and CaO,but significantly higher in incompatible elements(e.g.,SiO_(2),Rb,and Sr).The magmatic crystallization temperatures of the syenogranites and alkaline granites are 874℃ and 819℃,*** their age gradually decreases(peak ages:322 Ma and 307 Ma,respectively),there is a gradual decrease in the T_(DM2)of the A-type granites and a gradual increase in theεNd(t)value from the Ulungur belt to the Kalamaili belt in East *** study of A-type granites is therefore one of the keys to understandi

关键词： A-type granite Zircon U-Pb Sr-Nd isotopes post-collision East Junggar

Changing law of launching pitching angular velocity of rotating missile

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Chinese Journal of Aeronautics 2014年第5期27卷 1171-1179页

作者： Liu guang Xu Bin Jiao Xiaojuan zhen Tiesheng Department of Mechanics and Engineering Science Fudan University Shanghai Electro-Mechanical Engineering Institute

In order to provide accurate launching pitching angular velocity（LPAV） for the exterior trajectory optimization design, multi-flexible body dynamics（MFBD） technology is presented to study the changing law of LPAV of the rotating missile based on spiral guideway. An MFBD virtual prototype model of the rotating missile launching system is built using multi-body dynamics modeling technology based on the built flexible body models of key components and the special force *** built model is verified with the frequency spectrum analysis. With the flexible body contact theory and nonlinear theory of MFBD technology, the research is conducted on the influence of a series of factors on LPAV, such as launching angle change, clearance between launching canister and missile,thrust change, thrust eccentricity and mass eccentricity, etc. Through this research, some useful values of the key design parameters which are difficult to be measured in physical tests are obtained. Finally,a simplified mathematical model of the changing law of LPAV is presented through fitting virtual test results using the linear regression method and verified by physical flight tests. The research results have important significance for the exterior trajectory optimization design.

关键词： LPAV MFBD Modeling Rotating missile Simulation Virtual prototyping

Size Distribution and Anisotropy of the Minor Phase Droplets in Polypropylene/Ethylene-Octene Copolymer Blends: Effects of Shear and Component Miscibility

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Chinese Journal of Polymer Science 2014年第1期32卷 9-20页

作者： Cheng-zhen Geng yan-ling Zhu guang-hui yang 傅强 Chao-liang Zhang Ke Wang Tian-nan Zhou College of Polymer Science and Engineering State Key Laboratory of Polymer Materials Engineering Sichuan University State Key Laboratory of Oral Diseases West China Hospital of Stomatology Sichuan University

In this work, polypropylene （PP）/octene-ethylene copolymer （POE） blends were injection-molded using the so- called dynamic packing injection technique, which imposed oscillatory shear on the gradually cooling melt during the packing solidification stage. In this way, the effect of shear on the size distribution and anisotropy of the minor phase droplets could be investigated. Besides, by using two kinds of POE with different octene contents, the effect of component miscibility was also studied. The results show that the droplet size is mainly determined by composition and miscibility, and droplet anisotropy is mainly determined by droplet size and shear. Most importantly, under the same processing condition, droplet anisotropy increases with droplet size, and there seems a linear fit between them, disregarding the miscibility factor. These results may provide guidance for preparing polymer blends with desired properties by tailoring their phase morphologies.

关键词： Shear Miscibility Size distribution Anisotropy Phase morphology.

Discrepancy between non-invasive prenatal testing result and fetal karyotype caused by rare confined placental mosaicism: A case report

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World Journal of Clinical Cases 2022年第24期10卷 8641-8647页

作者： zhen Li guang-Rui Lai Department of Obstetrics and Gynecology Shengjing Hospital of China Medical UniversityShenyang 110004Liaoning ProvinceChina Department of Clinical Genetics Shengjing Hospital of China Medical UniversityShenyang 110004Liaoning ProvinceChina

BACKGROUND Confined placental mosaicism(CPM)is one of the major reasons for discrepancies between the results of non-invasive prenatal testing(NIPT)and fetal karyotype *** SUMMARY We encountered a primiparous singleton pregnant woman with a rare CPM consisting of 47,XY,+21;47,XXY;and 46,XY,who obtained a false-positive result on NIPT with a high risk for trisomy ***-number variation sequencing on amniotic fluid cells,fetal tissue,and placental biopsies showed that the fetal karyotype was 47,XXY,while the placenta was a rare mosaic of 47,XY,+21;47,XXY;and 46,*** The patient had a rare CPM consisting of 47,XY,+21;47,XXY;and 46,XY,which caused a discrepancy between the result of NIPT and the actual fetal *** is important to remember that NIPT is a screening test,not a diagnostic *** positive result should be confirmed with invasive testing,and routine ultrasound examination is still necessary after a negative result.

关键词： Non-invasive prenatal testing Confined placental mosaicism Copy-number variation sequencing Karyotype analysis Case report

Dynamic Response Study of Steel Catenary Riser Based on Slender Rod Model

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China Ocean Engineering 2019年第1期33卷 57-64页

作者： LIU zhen GUO Hai-yan College of Engineering Ocean University of China

A numerical model of the steel catenary riser(SCR) is built based on the slender rod model. The slender rod model,which describes the behavior of the slender riser in terms of the center line position, can solve the geometrical nonlinearity effectively. In a marine environment, the SCR is under the combined internal flow and external loads,such as wave and current. A general analysis considers only the inertial force and the drag force caused by the wave and current. However, the internal flow has an effect on the SCR; it is essential to explore the dynamic response of the SCR with the internal flow. The SCR also suffers the lift force and the fluctuating drag force because of the current. Finite element method is utilized to solve the motion equations. The effects of the internal flow, wave and current on the dynamic response of the SCR are considered. The results indicate that the increase of the internal flow density leads to the decrease of the displacement of the SCR, while the internal flow velocity has little effect on the SCR. The displacement of the SCR increases with the increase of the wave height and period. And the increasing wave period results in an increase in the vibration period of the SCR. The current velocity changes the displacements of the SCR in x-and z-directions. The vibration frequency of the SCR in y-direction increases with the increase of the current velocity.

关键词： steel catenary riser slender rod model internal flow dynamic response

Jensen’s Inequality Under Nonlinear Expectation Generated by BSDE with Jumps

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Acta Mathematicae Applicatae Sinica 2019年第4期35卷 873-884页

作者： Na ZHANG guang-yan JIA School of Science Tianjin University of Technology Tianjin 300384 China Zhongtai Securities Institute for Financial Studies Shandong University Jinan 250100 China

In this paper, we study Jensen’s inequality under f-expectation, which is a nonlinear expectation generated by backward stochastic differential equations(BSDEs) with jumps. We connect f-convex functions with the viscosity solutions of a kind of integral partial differential equations(IPDEs) with non-local *** find that under Lipschitz condition, the f-convex function is still convex in the usual sense, i.e., the jumps shrink the range of ‘convex’ functions.

关键词： backward stochastic differential equation with jumps f-convexity Jensen’s inequality