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AERODYNAMIC CHARACTERISTICS ABOUT MINING DUMP TRUCK AND THE IMPROVEMENT OF HEAD SHAPE

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Journal of Hydrodynamics 2008年第6期20卷 713-718页

作者： WEI Xiu-ling WANG Guo-qiang FENG Su-li College of Mechanical Science and Engineering Jilin University Changchun 130022 China department of Aeronautic Mechanical Engineering Aviation University of Air force Changchun 130022 China Fundamental Science department Armor Technique Institute Changchun 130117 China

The external flow field around a certain mining dump truck was simulated. The airflow structure and the aerodynamic drag were discussed, and the relationship between airflow characteristics and aerodynamic drag were obtained. In order to solve the problem of head shape of the truck, three scenarios including edge rounding, installing splitter planes and their combination were put forward to improve the head shape through numerical simulation and analysis. The model and method were selected to be three dimensional and time-independent. The Reynolds-averaged Navier-Stokes equations were solved using the finite volume method. The RNG k-ε model was chosen for the closure of the turbulent quantities. The results show that the third scenario is the best one, because of its aerodynamic characteristics being better than those of unimproved model.

关键词： dump truck external flow field numerical simulation

Ginkgo from Lower Cretaceous Changcai Formation in Helong of jilin, NE china

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Global Geology 2005年第Z1期 1-8页

作者： SUN Yue-wu, WANG Yu-xin, WEI Wen-yan Research Center of Palaeontology & Stratigraphy, jilin university, changchun 13.026, jilin, {3. College of earth sciences, jilin university, changchun 130061, jilin, {3.

Based on gross morphological and cuticular study, two species of Ginkgo From the Lower Cretaceous Changcai Formation in Helong of jilin. were identified from this area for the first time, including Ginkgo coriacea Florin and G. sibirica Heer. The study is significant for better understanding the paleophytogeographic, paleoecologic and stratigraphic characters of the Early Cretaceous Changcai flora.

关键词： Ginkgo cuticle Lower Cretaceous Changcai Formation jilin of china

Some properties on multivariate filter banks with a matrix factorization

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Progress in Natural Science:Materials International 2005年第2期15卷 20-30页

作者： LIAN Qiaofang1, XIAO Hongying2* and CHEN Qiuhui3.1. department of Mathematics, Beijing Jiaotong university, Beijing 100044, china 2. Institute of Mathematics, Academy of Mathematics and System {3., Chinese Academy of {3., Beijing 100080, china 3. department of Scientific Computing and Computer Applications, Zhongshan university, Guangzhou 510275, china) Dept. of Mathematics Beijing Jiaotong Univ. Beijing 100044 China Inst. of Mathematics Acad. of Math. and System Sci. Chinese Acad. of Sciences Beijing 100080 China Dept. of Scientific Computing Zhongshan Univ. Guangzhou 510275 China

A class of multivariate filter banks with a matrix factorization has been developed by Chen et al. The main purpose of this paper is to discuss some further properties of this kind of filter bank, such as the completeness, accuracy of the corresponding scaling functions and the relationships with Daubechies' wavelets and the multi-wavelets provided by Chui and Lian. Moreover, some examples are given to show that this kind of filter bank has a higher accuracy for the scaling functions.

关键词： filter banks completeness accuracy matrix factorization

Study on lithogeochemistry of Middle Jurassic basalts from southern china represented by the Fankeng basalts from Yongding of Fujian Province

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Science china earth sciences 2006年第10期49卷 1020-1031页

作者： ZHOU Jincheng1,2, JIANG Shaoyong1,2, WANG Xiaolei1,2, YANG Jinghong 1,2 & ZHANG Mengqun 3.1. State Key Laboratory of Mineral Deposit Research, Nanjing university, Nanjing 210093. china 2. department of {3. sciences, Nanjing university, Nanjing 210093. china 3. Modern Analysis Center, Nanjing university, Nanjing 210093. china State Key Laboratory of Mineral Deposit Research Nanjing University Nanjing China department of earth sciences Nanjing University Nanjing China Modern Analysis Center Nanjing University Nanjing China

There exists an E-W trending Middle Jurassic volcanic zone in southern china. The Fankeng basalts in the Yongding basin of Fujian Province are considered to be a typical example. The Fankeng basalts have TiO2 contents in the range of 1.92%-3.21%. They are classified as high-Ti basalts. They also have higher total Fe (averaging FeO* = 11.09%). The Middle Jurassic Fankeng basalts from southwestern Fujian have obvious distinctive lithogeochemical features from early Cre- taceous basalts from southeastern coast of china. They have higher HFSE, such as Th, Nb, Ta, Zr and Ti. Their element ratios related with HFSE, such as Zr/Ba, La/Nb, La/Ta ,Zr/Y, Ti/Y, Ba/Nb, K/Ti and Rb/Zr are similar to those of OIB. The most samples have ε Nd(T) of-0.70-0.24, which are near chondrite. Some samples have higher ε Nd(T) of ***, these basaltic magmas might be derived from depleted asthenospheric mantle. The lithogeochemical characteristics of the Fankeng basalts may be caused by interaction between asthenosphere and lithosphere at the time. The (Early-) Middle Jurassic basalts and gabbros from southeastern Hunan, southern Jiangxi and northern Guangdong provinces show similar geochemical features to those of the Fankeng basalts from the Yongding of Fujian. Occurrence of these OIB-type basalts in the area may be regarded as the petrological mark of upwelling of asthenosphere at the time. Upwelling of asthenosphere has led to tectonic extension and the formation of rifted basin in the area.

关键词： interaction between asthenosphere and lithosphere, lithogeochemistry, basalts, Middle Jurassic, southern china.

Mesozoic Volcanic-Intrusive Complexes in the Coastal Area of Southeastern Zhejiang Province: Their Features, Petrogenesis and Distribution Pattern

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Acta Geologica Sinica(English Edition) 1991年第1期65卷 37-49页

作者： Du Yangsong Wang Dezi Chen Kerong department of earth sciences, Nanjing {3., Nanjing department of earth sciences Nanjing University Nanjing

On the basis of previous studies and by means of field geological, remote sensing, petrographical,mineralogical, petrochemical and geochemical investigations, the authors studied the temporal-spatial distribu-tion of the regional structures, volcanic structures and products of volcanic activity in the coastal area ofsoutheastern Zhejiang. On the basis and through a systematic comparison of the products of magmatism in thearea, it is considered that there exists a compsite volcanic structural belt composed of linear and circular struc-tures and it has been demonstrated that there exist volcanic intrusive complexes--'trinity' composed of vol-canic, subvolcanic and plutonic rocks. It is suggested that the volcanic intrusive complexes in the area belong tothe typical syntexis series and that its materials were derived from a mixed source of crust and mantle.

关键词： Petrogenesis and Distribution Pattern Their Features Mesozoic Volcanic-Intrusive Complexes in the Coastal Area of Southeastern Zhejiang Province

South china's Gondwana connection in the Paleozoic:Paleomagnetic evidence

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Progress in Natural Science:Materials International 2004年第1期14卷 86-91页

作者： ZHANG Shihong*(School of earth sciences and Resources, china {3. of Geosciences, Beijing 100083. china) china Univ Geosci Sch Earth Sci & Resources Beijing 100083 Peoples R China

The reconstruction in which the South china Block (SCB) lies along the Great India Australia region of Gondwana margin is tested by using existing Paleozoic paleomagnetic data. Under the proposed reconstruction, all six high quality paleopoles from the SCB between the Early Cambrian and late Early Devonian (～400 Ma) are in good agreement with coeval paleopoles from Gondwana. Thereafter, the apparent polar wander paths for the SCB and Gondwana diverge markedly. This indicates that the SCB had been part of Gondwana and the connection was intact from at least Early Cambrian until late Early Devonian, but they began to separate by late Middle Devonian (～3.5 Ma).

关键词： South china block Gondwana paleomagnetism reconstruction

Coronal Flux Rope Equilibria in Closed Magnetic Fields

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Chinese Journal of Astronomy and Astrophysics 2003年第3期3卷 241-246页

作者： Zhen Wang and You-Qiu HuSchool of earth and Space sciences, university of Science and Technology of {3., School of earth and Space sciences University of Science and Technology of China Hefei 230026

Using a 2.5-dimensional ideal MHD model in Cartesian coordinates, weinvestigate the equilibrium properties of coronal magnetic flux ropes in background magnetic fieldsthat are completely closed. The background fields are produced by a dipole, a quadrupole, and anoctapole, respectively, located below the photosphere at the same depth. A magnetic flux rope isthen launched from below the photosphere, and its magnetic properties, i.e., the annular magneticflux Φ_p and the axial magnetic flux Φ_z, are controlled by a single emergence parameter. Thewhole system eventually evolves into equilibrium, and the resultant flux rope is characterized bythree geometrical parameters: the height of the rope axis, the half-width of the rope, and thelength of the vertical current sheet below the rope. It is found that the geometrical parametersincrease monotonically and continuously with increasing Φ_p and Φ_z: no catastrophe ***, there exists a steep segment in the profiles of the geometrical parameters versus eitherΦ_p or Φ_z, and the faster the background field decays with height, the larger both the gradientand the growth amplitude within the steep segment will be.

关键词： sun: magnetic fields sun: corona

Characteristics of fMRI BOLD signal and its neurophysiological mechanism

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Progress in Natural Science:Materials International 2007年第6期17卷 630-638页

作者： Zhao Xiaohu1,2, Wu Yigen3.and Guo Shengli3.1. College of Life sciences, Zhejiang university, Hangzhou 3.0058, china 2. Imaging {3. of Tongji Hospital of Tongji university, Shanghai 200065, china 3. College of Mathematics and Physics, Nanjing university of Information Science and Technology, Nanjing 210044, china) College of Life sciences Zhejiang University Hangzhou 310058 China Imaging department Tongji Hospital Tongji University Shanghai 200065 China College of Mathematics and Physics Nanjing University of Information Science and Technology Nanjing 210044 China

The functional magnetic resonance imaging (fMRI) based on blood oxygen level dependent (BOLD) contrast has emerged as one of the most potent noninvasive tools for mapping brain function and has been widely used to explore physiological, pathological changes and mental activity in the brain. Exploring the nature and property of BOLD signal has recently attracted more attentions. Despite that great progress has been made in investigation of the characteristics and neurophysiological basis, the exact nature of BOLD signal remains unclear. In this paper we discuss the characteristics of BOLD signals, the nonlinear BOLD response to external stimuli and the relation between BOLD signals and neural electrophysiological recordings. Furthermore, we develop our new opinions regarding nonlinear BOLD response and make some perspectives on future study.

关键词： functional magnetic resonance imaging blood oxygen level dependent nonlinear response neural electrophysiological activity.

Boron nitride microribbons strengthened and toughened alumina composite ceramics with excellent mechanical,dielectric,and thermal conductivity properties

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Journal of Advanced Ceramics 2024年第4期13卷 496-506页

作者： jilin Wang Dongping Lu Weiping Xuan Yuchun Ji Ruiqi Chen Shaofei Li Wenbiao Li Wenzhuo Chen Shilin Tang Guoyuan Zheng Fei Long Guangxi Key Laboratory of Optical and Electronic Materials and Devices Collaborative Innovation Center for Exploration of Nonferrous Metal Deposits and Efficient Utilization of ResourcesSchool of Materials Science and EngineeringGuilin University of TechnologyGuilin 541004China Key Laboratory of New Processing Technology for Nonferrous Metals and Materials of Ministry of Education Guilin University of TechnologyGuilin 541004China School of Materials Science and Engineering Peking UniversityBeijing 100871China department of Civil and Environmental Engineering The Hong Kong Polytechnic UniversityKowloon 999077Hong KongChina

Aluminum oxide(Al_(2)O_(3.)ceramics have been widely utilized as circuit substrates owing to their exceptional *** this study,boron nitride microribbon(BNMR)/Al_(2)O_(3.composite ceramics are prepared using spark plasma sintering(SPS).This study examines the effect of varying the amount of toughened phase BNMR on the density,mechanical properties,dielectric constant,and thermal conductivity of BNMR/Al_(2)O_(3.composite ceramics while also exploring the mechanisms behind the toughening and increased thermal conductivity of the fabricated *** results showed that for a BNMR content of 5 wt%,BNMR/Al_(2)O_(3.composite ceramics displayed more enhanced characteristics than pure Al_(2)O_(3.*** particular,the relative density,hardness,fracture toughness,and bending strength were 99.95%±0.025%,3..11±1.5 GPa,5.42±0.21 MPa·m^(1/2),and 3.5±2.5 MPa,*** values represent increases of 0.76%,70%,3.%,and 25%,respectively,compared with the corresponding values for pure Al_(2)O_(3.***,during the SPS process,BNMRs are subjected to high temperatures and pressures,resulting in the bending and deformation of the Al_(2)O_(3.matrix;this leads to the formation of special thermal pathways within *** dielectric constant of the composite ceramics decreased by 25.6%,whereas the thermal conductivity increased by 45.6%compared with that of the pure Al_(2)O_(3.*** results of this study provide valuable insights into ways of enhancing the performance of Al_(2)O_(3.-based ceramic substrates by incorporating novel BNMRs as a second *** improvements are significant for potential applications in circuit substrates and related fields that require high-performance materials with improved mechanical properties and thermal conductivities.

关键词： boron nitride microribbons/aluminum oxide(BNMRs/Al_(2)O_(3.)composite ceramics boron nitride microribbon(BNMR) spark plasma sintering(SPS) strengthening and toughening thermal conductivity