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Image of local energy anomaly during a heavy rainfall event

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chinese Physics B 2017年第11期26卷 565-573页

作者：杨帅左群杰高守亭 laboratory of Cloud-Precipitation Physics and Severe Storms (LACS) Institute of Atmospheric PhysicsChinese Academy of Sciences State key laboratory of Severe Weather Chinese Academy of Meteorological Sciences

A clear and interesting image of local total energy anomaly(EA) is depicted for a heavy rainfall event in this *** the convection development, it exhibits a positive local EA, implying local total energy(TE) experiences heaping up to prepare for the future system development. As the convection grows, it transforms into an opposite spatial modality with negative EA dominant, which means that the local TE is consumed to feed the convection growth in the middle and lower levels. The local total EA has consistent variation regular in intensity with severe weather system evolution. By utilizing the local TE budget equation in variable density fluid, the flux divergence of energy and its components are investigated, which could account for the local TE variation better. To relax the restriction and complexity introduced by identifying sporadic and alternative positive/negative signals of EA, the method taking the absolute-value operator on energy flux divergence is used to further simplify analyses. The derived characteristic signal of absolute EA is clearer and cleaner than ***, the EA could be illustrated based on the active degree of energy supply/consumption in a generalized sense whatever positive or negative anomaly should be it, which could be used easily to identify and even predict the system development for operational application. Note that, although two sets of methodologies are used to define EA herein, they play absolutely different roles in nature throughout the whole context. For example, the taking-perturbation method provides a diagnostic tool to portray a preliminary sketch and to give sufficient necessity of this research, while tendency equation of local TE illuminates more predictive sense and accounts for future local EA related to following system evolution. Therefore, the latter could be a more effective tool to routine usage.

关键词： local energy anomaly energy budget equation heavy rainfall

Crystallization behavior of zeolite beta from acid-leached metakaolin

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Petroleum Science 2010年第4期7卷 541-546页

作者： Li Qiang Zhang Ying Cao Zhijun Gao Wei Cui Lishan Department of Materials Science and Technology China University of Petroleum Beijing 102249 China National key laboratory of Multiphase Complex System Institute of Process Engineering Chinese Academy of Sciences Beijing 100190 China Microstructure laboratory for energy Materials China University of Petroleum Beijing 102249 China

Well-crystallized zeolite beta was synthesized by using acid-leached metakaolin as the silica-alumina source and tetraethylammonium hydroxide structure-directing *** influence of the composition of the reaction mixture on product crystallinity was investigated,and the crystallization process was studied by examining solid samples obtained at different synthesis *** showed that the acid-leached metakaolin was fully converted into soluble aluminum and silicon species,which is crucial for the formation of well-crystallized zeolite *** the beginning of the crystallization process,these soluble aluminum and silicon species formed a aluminum-rich intermediate structure with layer *** the crystallization proceeding,more silicon species were incorporated into the zeolite beta framework and the layered structure was changed into spherical particles of zeolite beta with high SiO 2 /Al 2 O 3 ratio and crystallinity.

关键词： Zeolite beta acid-leached metakaolin tetraethylammonium hydroxide (TEAOH) liquid phase transformation mechanism

Analytical method of radiation by a wave energy device with dual rectangular floating bodies

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Acta Oceanologica Sinica 2010年第3期29卷 106-115页

作者： WANG Wensheng YOU Yage ZHANG Yunqiu WU Bijun YE Yin Guangzhou Institute of energy Conversion Chinese Academy of Sciences Guangzhou 510640 China key laboratory of Renewable energy and Gas Hydrate Chinese Academy Sciences Guangzhou 510640 China Graduate University Chinese Academy of Sciences Beijing 100049 China

The system with one floating rectangular body on the free surface and one submerged rectangular body has been applied to a wave energy conversion device in water of finite depth. The radiation problem by this device on a plane incident wave is solved by the use of an eigenfunction expansion method, and a new analytical expression for the radiation velocity potential is obtained. The wave excitation force is calculated via the known incident wave potential and the radiation potential with a theorem of Haskind employed. To verify the correctness of this method, an example is computed respectively through the bound element method and analytical method. Results show that two numerical methods. are in good agreement, which shows that the present method is applicable. In addition, the trends of hydrodynamic coefficients and wave force are analyzed under different conditions by use of the present analytical method.

关键词： wave energy device hydrodynamic coefficients wave force analytical method

Sediment transport capacity of hyperconcentrated flow

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Science china(Physics,Mechanics & Astronomy) 2008年第8期51卷 961-975页

作者： SHU AnPing1,2 & FEI XiangJun2 1 School of Environment & key laboratory of Water and Sediment sciences,Ministry of Education,beijing Normal University,beijing 100875,china 2 State key laboratory of Hydroscience and Engineering,Tsinghua University,beijing 100084,china School of Environment & key laboratory of Water and Sediment sciences Ministry of Education Beijing Normal University Beijing 100875 China State key laboratory of Hydroscience and Engineering Tsinghua University Beijing 100084 China

As one of the most important components of river mechanics,sediment transport capacity of sediment-laden flows has attracted much attention from many researchers working on river mechanics and hydraulic engineering. Based on the time-averaged equation for a turbulent energy equilibrium in solid and liquid two-phase flow,an expression for the efficiency coefficient of suspended load movement was derived for the two-dimensional,steady,uniform,fully-developed turbulent flow. A new structural expression of sediment transport capacity was achieved. Using 115 runs of flume experimental data,which were obtained through two kinds of sediment transport experiments in the state of equilibrium,in combination with the basic rheological and sediment transporting characteristics of hyperconcentrated flow,the main parameters in the structural expression of sediment transport capacity were calibrated,and a new formula of sediment transport capacity for hyperconcentrated flow was developed. A large amount of field data from the Yellow River,Wuding River,and Yangtze River,etc. were adopted to verify the new formula and good agreement was obtained. These results above contribute to an improved theoretical system of river mechanics and a reliable tool for management of rivers carrying high concentration of sediments.

关键词： hyperconcentrated flow turbulent energy equilibrium efficiency coefficient sediment transport capacity

Improved formula of coronal magnetic field strength diagnostic

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chinese Science Bulletin 1997年第3期42卷 234-236页

作者： ZHOU AihuaPurple Mountian Observatory, chinese academy of sciences, Nanjing 210008, china Purple Mountian Observatory Chinese Academy of Sciences Nanjing 210008 China

CORONAL magnetic field is one of the most important physical quantities in the solar coronal atmosphere, and it is the key to an understanding of the origin and energy release of solar flares too. In most cases, microwave (MW) bursts are caused by reactions between mildly relativistic electrons and the coronal magnetic fields. So MW burst spectrum should embody the infor-

关键词： microwave burst spectrum coronal magnetic field.

Microstructure refinement and magnetic properties enhancement of nanocrystalline Nd_(12.3)Fe_(81.7)B_(6.0) ribbons by addition of Zr

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Science china(Technological sciences) 2009年第7期52卷 1891-1896页

作者： BAO XiaoQian, QIAO Yi, GAO XueXu, ZHU Jie & ZHOU ShouZeng State key laboratory for advanced Metals and Materials, University of Science and Technology beijing, beijing 100083, china 1. State key laboratory for advanced Metals and Materials University of Science and Technology Beijing Beijing 100083 China

Effects of Zr addition and annealing treatment on the formation, microstructure and magnetic properties of Nd12.3Fe81.7?xZrxB6.0 (x=0―3.0) ribbons melt-spun and annealed have been systematically investigated by means of vibrating sample magnetometer (VSM), differential scanning calorimeter (DSC), X-ray diffraction (XRD), and high resolution scanning electron microscopy (HRSEM). Phase analysis reveals that Nd2Fe14B is single-phase material. It has been found that the intrinsic coercivity Hci of the optimally processed Nd12.3Fe81.7?xZrxB6.0 ribbons increases monotonically from 751.7 kA/m for x=0 to 1005.3 kA/m for x=3.0. The remanence polarization Jr and maximum energy product (BH)max increase first with Zr addition, then slightly decrease with further increasing Zr content. Optimum magnetic properties with Jr=1.041 T, Hci=887.5 kA/m and (BH)max=175.2 kJ/m3 have been achieved for the ribbons with x=1.5. The significant improvement of magnetic properties originates from the finer grains of the ribbons by introducing Zr.

关键词： Nd-Fe-B magnets nanocrystalline microstructure magnetic properties

Influence of synthesis parameters on the crystallinity and Si/Al ratio of NaY zeolite synthesized from kaolin

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Petroleum Science 2010年第3期7卷 403-409页

Well-crystallized high-silica NaY zeolites （Si/Al〉2.5） were prepared from a reaction mixture consisting of metakaolin, sodium silicate solution and seed solution via optimization of the mixture composition and reaction conditions. The transformation from kaolin to high-silica NaY zeolite was confirmed by XRD, SEM and IR techniques. Subsequently, the influence of synthesis parameters, i.e. initial SIO2/Al2O3, initial Na2O/SiO2, initial H2O/SiO2, aging time of the seed solution, crystallization temperature and crystallization time, on the NaY growth was investigated in terms of crystallinity and Si/Al ratio. The results showed that the effects of initial SiO2/Al2O3, initial Na2O/SiO2 and initial H2O/ SiO2 on the crystaIlinity and Si/Al ratio of NaY zeolite are similar to those observed in the conventional syntheses of NaY zeolites only using sodium silicate solution as silicon source. However, due to the use of metakaolin as the main silicon and aluminum sources in the present study, a long crystallization induction period of 20 h was achieved, which can be attributed to the dissolution of metakaolin. In addition, different from the conventional syntheses of zeolite NaY, pure NaY zeolites （i.e. without NaP zeolite impurity） were still obtained even at 120℃ because of the use of a large quantity of seed solution （23 wt%） in the reaction mixture. As the aging time of the seed solution increased from 3.5 h to 22 h, the relative crystallinity of the NaY zeolite first increased sharply and then reached a plateau, while the Si/Al ratio first increased rapidly up to a maximum value of 2.75 corresponding to an aging time of 6.5 h, and then decreased sharply with the aging time.

关键词： Kaolin NaY zeolite high-silica seed solution aging time crystallinity

Temporal study of GRS 1915+105 with rms-flux relation:The importance of magnetic activities in the corona

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Science china(Physics,Mechanics & Astronomy) 2010年第S1期53卷 120-124页

作者： HAN Dong1,ZHANG ShuangNan2 & SONG LiMing2 1 Department of Engineering Physics & Center for Astrophysics,Tsinghua University,beijing 100084,china 2 key laboratory of Particle Astrophysics,Institute of High energy Physics,chinese academy of sciences,beijing 100049,china 1. Department of Engineering Physics & Center for Astrophysics Tsinghua University Beijing 100084 China 2. key laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China

The rms-flux relations for some observations of GRS 1915+105 are *** rms-flux relations of the light curves in only one state,state C or state A,can be described by the simple non-linear model provided Zhang;we thus interpret that such a linear relation reflects the relative importance of magnetic instability for X-ray emission in the corona of the system,compared to the thermal viscous instability for the X-ray emission in the accretion *** rms-flux relations for state B are very scattered,possibly because of the dominance of thermal viscous instability for the X-ray emission in the accretion *** complex rms-flux relations for the observations of transitions between two or three states are caused by the combination of the different rms-flux relations of these *** underlying physical processes are the combination of magnetic topology in the corona and thermal viscous instability in the accretion disk.

关键词： rms-flux relation data analysis GRS 1915+105 magnetic instability

Optimal speed of hypersonic cruise flight

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Theoretical & Applied Mechanics Letters 2011年第1期1卷 50-52页

作者： Jing Fan~(a)) key laboratory of High Temperature Gas Dynamics,Institute of Mechanics,chinese academy of sciences, beijing 100190,china key laboratory of High Temperature Gas Dynamics Institute of Mechanics Chinese Academy of Sciences Beijing 100190 China

A coupling frame of speed gain and maintain was suggested to assess the flight performance of hypersonic cruise vehicles(HCV).The optimal cruise speed was obtained by analyzing the flight performance measured by the ratio of initial boost mass to generalized *** performance of HCVs based on rockets and air-breathing ramjets was studied and compared to that of a minimum-energy ballistic trajectory under a certain flight *** is concluded that rocket-based HCVs flying at the optimal speed are a very competitive choice at the current stage.

关键词： hypersonic cruise vehicle flight performance optimal cruise speed