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A Middle Triassic stem-neopterygian fish from China sheds new light on the peltopleuriform phylogeny and internal fertilization

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Science Bulletin 2016年第22期61卷 1766-1774页

作者： guang-Hui xu Xin-Ying Ma Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences Institute of Vertebrate Paleontology and Paleoanthropology Chinese Academy of Sciences

Internal fertilization and viviparity are easily observed and well studied in living neopterygian fishes(14teleostean families), but they are difficult to identify in extinct taxa due to the limitation of the fossil record. The Peltopleuriformes from the Middle to Late Triassic of Europe and South China are a stem group of Neopterygii that may have first evolved internal fertilization and viviparity in this clade because they show a highly modified anal fin in presumed males resembling the intromittent organ in living viviparous teleosts. Until recently, Peltopleurus lissocephalus and P. rugosus from the Ladinian/Anisian boundary(*242 Ma) of Monte San Giorgio area in Switzerland and Italy represent the oldest record of Peltopleuriformes, and the phylogenetic interrelationships of this group remain controversial. Here, we report the discovery of a new peltopleuriform, Peltopleurus nitidus sp. nov., based on eleven well-preserved specimens from the early Middle Triassic(Pelsonian, Anisian, *244 Ma)of Luoping, eastern Yunnan, China. The discovery documents the oldest convincing peltopleuriform, extending the geological range of this clade by proximately two million years. Results of the phylogenetic analysis recover *** at the base of Peltopleuridae, and provide robust support for the sister-group relationships of Peltopleuridae with Thoracopteridae within the Peltopleuriformes. The male anal fin of P. nitidus shows a primitive condition unknown in other peltopleuriforms. Comparative studies of the male anal fin in P. nitidus and other peltopleuriforms shed new light on the internal fertilization in this group.

关键词： Sexual dimorphism Viviparity Peltopleuridae Thoracopteridae Triassic

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ACCELERATION METHODS OF NONLINEAR ITERATION FOR NONLINEAR PARABOLIC EQUATIONS

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Journal of Computational Mathematics 2006年第3期24卷 412-424页

作者： guang-wei Yuan xu-deng Hang Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics P.O.Box 8009 Beijing 100088 China

This paper discusses the accelerating of nonlinear parabolic equations. Two iterative methods for solving the implicit scheme new nonlinear iterative methods named by the implicit-explicit quasi-Newton （IEQN） method and the derivative free implicit-explicit quasi-Newton （DFIEQN） method are introduced, in which the resulting linear equations from the linearization can preserve the parabolic characteristics of the original partial differential equations. It is proved that the iterative sequence of the iteration method can converge to the solution of the implicit scheme quadratically. Moreover, compared with the Jacobian Free Newton-Krylov （JFNK） method, the DFIEQN method has some advantages, e.g., its implementation is easy, and it gives a linear algebraic system with an explicit coefficient matrix, so that the linear （inner） iteration is not restricted to the Krylov method. Computational results by the IEQN, DFIEQN, JFNK and Picard iteration methods are presented in confirmation of the theory and comparison of the performance of these methods.

关键词： Nonlinear parabolic equations Difference scheme Newton iterative methods.

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3D analysis for pit evolution and pit-to-crack transition during corrosion fatigue

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2013年第4期14卷 292-299页

作者： Xiao-guang HUANG Jin-quan xu Department of Engineering Mechanics China University of Petroleum Department of Engineering Mechanics Shanghai Jiao Tong University

This paper presents a deterministic model to predict the pit evolving morphology and crack initiation life of corrosion *** on the semi-ellipsoidal pit assumption,the thermodynamic potential including elastic energy,surface energy and electrochemical energy of the cyclically stressed solid with an evolving pit is established,from which specific parameters that control the pit evolution are introduced and their influence on the pit evolution are *** critical pit size for crack nucleation is obtained from stress intensity factor criterion and the crack nucleation life is evaluated by Faraday's ***,this paper presents a numerical example to verify the proposed model and investigate the influence of cyclic load on the corrosion fatigue crack nucleation *** corrosion pit appears approximately as a hemisphere in its early formation,and it gradually transits from semicircle to *** strain energy accelerates the morphology evolution of the pit,while the surface energy decelerates *** higher the stress amplitude is,the smaller the critical pit size is and the shorter the crack initiation life is.

关键词： Pit Evolving morphology Thermodynamic potential Critical pit size Crack nucleation

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Prediction of oxygen concentration and temperature distribution in loose coal based on BP neural network

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Mining Science and Technology 2009年第2期19卷 216-219页

作者： ZHANG Yong-jian WU Guo-guang xu hong-feng MENG Xian-liang WANG guang-you School of Chemical Engineering and Technology China University of Mining ＆ Technology Xuzhou Jiangsu 221008 China

An effective method for preventing spontaneous combustion of coal stockpiles on the ground is to control the air-flow in loose coal. In order to determine and predict accurately oxygen concentrations and temperatures within coal stockpiles, it is vital to obtain information of self-heating conditions and tendencies of spontaneous coal combustion. For laboratory conditions, we designed our own experimental equipment composed of a control-heating system, a coal column and an oxygen concentration and temperature monitoring system, for simulation of spontaneous combustion of block coal （13-25 mm） covered with fine coal （0-3 mm）. A BP artificial neural network （ANN） with 150 training samples was gradually established over the course of our experiment. Heating time, relative position of measuring points, the ratio of fine coal thickness, artificial density, voidage and activation energy were selected as input variables and oxygen concentration and temperature of coal column as output variables. Then our trained network was applied to predict the trend on the untried experimental data. The results show that the oxygen concentration in the coal column could be reduced below the minimum still able to induce spontaneous combustion of coal - 6% by covering the coal pile with fine coal, which would meet the requirement to prevent spontaneous combustion of coal stockpiles. Based on the prediction of this ANN, the average errors of oxygen concentration and temperature were respectively 0.5% and 7 ℃, which meet actual tolerances. The implementation of the method would provide a practical guide in understanding the course of self-heating and spontaneous combustion of coal stockpiles.

关键词： loose coal neural netwOrk spontaneous combustion of coal oxygen concentration temperature prediction

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Development and application of moment method on nanoparticles evolution due to coagulation and deposition

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Journal of Hydrodynamics 2019年第5期31卷 1011-1020页

作者： guang-ping xu Jia-song Wang School of Naval Architecture Ocean and Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China

In this study,the Taylor-series expansion method of moments is developed to describe the dynamic behaviour of nanoparticles considering both the effects of coagulation and deposition in closed environments,where the two effects have always been studied separately *** with traditional methods of moments,the new method could give more accurate results for solving the general dynamics *** addition,moment equations with respect to coagulation and deposition considering the fractal dimension(Df)of particles are acquired,and the results are compared with experimental data and are more accurate than the simulation results under the assumption of spherical *** new dynamic model could be applied in more real conditions with different microstructures of *** decreasing Dt,the particle number concentration decreases more rapidly,additionally,Df has a relatively greater effect on the agglomeration of smaller particles under the same initial ***,the effect of the initial number concentration on coagulation is also *** results show that a higher initial number concentration or a smaller particle size could have a greater effect of coagulation on the evolution of particles.

关键词： Moment method nanoparticle deposition coagulation fractal dimension

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An Annular Gap Acceleration Model for γ-ray Emission of Pulsars

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Chinese Journal of Astronomy and Astrophysics 2007年第4期7卷 496-502页

作者： Guo-Jun Qiao Ke-Jia Lee Bing Zhang hong-guang Wang Ren-Xin xu Department of Astronomy Peking University Beijing 100871 Department of Physics University of Nevada Las Vegas Nevada 89154 USA Center for Astrophysics Guangzhou University Guangzhou 510400

If the binding energy of the pulsar＇s surface is not so high （the case of a neutron star）, both negative and positive charges will flow out freely from the surface of the star. An annular free flow model for 7-ray emission of pulsars is suggested. It is emphasized that：（1） Two kinds of acceleration regions （annular and core） need to be taken into account. The annular acceleration region is defined by the magnetic field lines that cross the null charge surface within the light cylinder. （2） If the potential drop in the annular region of a pulsar is high enough （normally the case for young pulsars）, charges in both the annular and the core regions could be accelerated and produce primary gamma-rays. Secondary pairs are generated in both regions and stream outwards to power the broadband radiations. （3） The potential drop grows more rapidly in the annular region than in the core region. The annular acceleration process is a key process for producing the observed wide emission beams. （4） The advantages of both the polar cap and outer gap models are retained in this model. The geometric properties of the 7-ray emission from the annular flow are analogous to that pre-sented in a previous work by Qiao et al., which match the observations well. （5） Since charges with different signs leave the pulsar through the annular and the core regions respectively, the current closure problem can be partially solved.

关键词： pulsars: general - pulsars: - radiation mechanisms: non-thermal - stars:neutron - elementary particles

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低场核磁共振测定鲜猪肉中水分分布的制样方法

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食品安全质量检测学报 2017年第6期8卷 2006-2011页

作者：黄子信吴美丹周光宏徐幸莲李春保南京农业大学食品科技学院教育部肉品加工与质量控制重点实验室农业部畜产品加工重点实验室南京210095

目的应用低场核磁共振技术(low field nuclear magnetic resonance,LF-NMR)测定不同鲜猪肉的制样方法(肉样大小、分切方向、是否包膜)的水分分布,以确定其较佳制样方法。方法以宰后24 h的猪背最长肌为对象,采用单因素实验,分别按不同大... 详细信息

目的应用低场核磁共振技术(low field nuclear magnetic resonance,LF-NMR)测定不同鲜猪肉的制样方法(肉样大小、分切方向、是否包膜)的水分分布,以确定其较佳制样方法。方法以宰后24 h的猪背最长肌为对象,采用单因素实验,分别按不同大小、不同分切方向和包膜与否进行3组实验,对LF-NMR的弛豫时间T_2相关指标进行方差分析和多重比较。结果随着肉样质量的增加,T_(2b)先减小后增大(P<0.05),A_(2b)、A21逐渐增加(P<0.05);肉样分切方向不影响样品水分含量分布测定结果;而包膜使样品的T_(2b)减小、A_(2b)和P-(2b)增加(P<0.05)。结论猪肉的制样样品大小为2.0 cm(长)×1.0 cm(宽)×1.0 cm(高),分切方向为沿肌肉方向,不包膜处理,这种制样方法对样品中水分分布情况的影响最小,能相对准确地反映实际样品中水分分布及含量。

关键词：猪肉制样水分分布低场核磁共振

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Plexiform fibromyxoma of the small bowel: A case report

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World Journal of Clinical Cases 2018年第15期6卷 1067-1072页

作者： Wei-guang Zhang Liang-Bi xu Yi-Ning Xiang Chen-hong Duan Depart-ment of Endoscopy the Affiliated Hospital of Guizhou Medical University Department of Pathology the Affiliated Hos-pital of Guizhou Medical University

BACKGROUND Plexiform fibromyxoma is a rare, special type of mesenchymal tumor. The most common presenting symptoms are anemia, hematemesis, and hematochezia, without sex or age predilection. The reported cases have mainly occurred in the gastric antrum and pylorus region, with some cases in the duodenum. CASE SUMMARY We report here a case of plexiform fibromyxoma in the upper segment of the jejunum, which was continuously followed up for 3 years after surgical removal. Plexiform fibromyxoma showed multinodular or plexiform growth. The cells in the tumor node were spindle-shaped but few in number and mitotic figures. Small blood vessels and mucous matrix were found among the tumor cells. Immunohistochemistry revealed that the plexiform fibromyxoma cells were positive for smooth muscle actin, focally positive for CD10, and negative for cytokeratin, CD117, DOG-1(discovered on GIST-1) desmin, S-100, epithelial membrane antigen, and CD34. Ki-67 labeling index was < 5%. Plexiform fibromyxoma showed benign biological behavior. After 3 years of consecutive postoperative follow-up, no obvious signs of metastasis or recurrence were found by imaging examination. CONCLUSION Plexiform fibromyxoma is a rare type of mesenchymal tumor. The diagnosis mainly depends on pathological examination, and it should be distinguished from other gastrointestinal mesenchymal tumors.

关键词： Plexiform fibromyxoma Gastrointestinal stromal tumor Plexiform angiomyxoid myofibroblastic tumor Small bowel Benign tumor Case report

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Oxidative Damage to DNA and Its Relationship With Diabetic Complications

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Biomedical and Environmental Sciences 2007年第2期20卷 160-163页

作者： hong-ZHI PAN DONG CHANG LEI-guang FENG FENG-JUAN xu hong-YU KUANG MING-JUN LU School of Public Health Harbin Medical University Harbin 150081 Heilongjiang China The First Affiliated Hospital of the Harbin Medical University Harbin 150001 Heilongjiang China

Objective To detect the oxidative DNA damage in diabetic patients and to investigate the relationship of oxidative DNA damage with diabetes and diabetic nephropathy. Methods Single cell gel electrophoresis （SCGE） was used to detect the DNA strand breaks in peripheral blood lymphocytes, and oxidative DNA damage product and serum 8-OHdG were determined by a competitive ELISA in 47 cases, including 25 patients without diabetic complications, 22 patients with diabetic nephropathy and 25 normal control subjects. Results Diabetic patients showed greater oxidative damage to DNA. The percentage of comet cells and the length of DNA migration （comet tail length） of peripheral blood lymphocytes were significantly increased in patients with diabetes, and significantly higher in patients with diabetic nephropathy than in diabetic patients without vascular complications （P〈0.05）. There was a significant increase in serum 8-OHdG in diabetic patients compared with normal subjects （P〈0.05）. Moreover, serum 8-OHdG was much higher in patients with diabetic nephropathy than in diabetic patients without vascular complications （P〈0.05）. Coneluslon There is severe oxidative DNA damage in diabetic patients. Enhanced oxidative stress may be associated with diabetes, especially in patients with diabetic nephropathy.

关键词： Diabetes Diabetic nephropathy Comet assay 8-OHdG

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Recent progress in Heusler-type magnetic shape memory alloys

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Rare Metals 2015年第8期34卷 527-539页

作者： guang-Hua Yu Yun-Li xu Zhu-hong Liu hong-Mei Qiu Ze-Ya Zhu Xiang-Ping Huang Li-Qing Pan Department of Materials Physics and Chemistry University of Science and Technology Beijing College of Science China Three Gorges University Department of Physics University of Science and Technology Beijing

Magnetic shape memory alloys(MSMAs), both in condensed matter physics and in material science, are one of the most extensive research subjects. They show prompt response to the external magnetic field and give rise to large strain and have fine reversibility. The well-known example is Heusler-type MSMAs, which possess excellent multifunctional properties and have potential applications in energy transducer, actuator, sensor, microelectromechanical system, and magnetic refrigerator. In this paper, it is shown the recent progress in magnetostructural transformation, magnetic properties, shape deformation, magnetocaloric effect as well as magnetic field-induced shape memory effect in Ni–Mn–Ga, Ni Mn Z(Z = In, Sn, Sb),and Ni Co Mn Z(Z = In, Sn, Sb, Al) Heusler-type *** remaining issues and possible challenges are briefly discussed.

关键词： Heusler alloy Magnetic shape memory alloy Martensi

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