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Behaviors of fine bubbles in the shroud nozzle of ladle and tundish

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Journal of university of Science and technology beijing 2003年第4期10卷 20-23页

作者： Yanping Boo, Jianhua Liu, and Baomei XuMetallurgical Engineering School, university of Science and technology beijing, beijing 100083, china Metall. Eng. Sch. Univ. of Sci. and Technol. Beijing Beijing 100083 China

Fine bubbles will create when the inert gas is introduced to the high rapidsteel stream within the shroud nozzle between ladle and tundish. The collision and attachment amongthe bubbles and fine inclusions will promote the floatation efficiency of inclusions in the *** behaviors of the bubbles, such as the dispersion in shroud, coalescence and floatation intundish, are studied. The results show that the maximum sizes of the bubbles in the water and steelflow within the shroud in the length of 1.2 m are 0.70-1.44 mm and 1.53-3.16 mm respectively whenthe flow rates are 0.006-0.016 m^3/s; the terminal velocities of fine bubbles in the water andmolten steel within the tundish are 0.02-0.2 and 0.05-0.6 m/s.

关键词： fine bubbles shroud nozzle of the ladle flotation

Multi-origin alkanes related to CO_2-rich, mantle-derived fluid in Dongying Sag, Bohai Bay Basin

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Chinese Science Bulletin 2002年第20期47卷 1756-1760页

作者： JIN Zhijun, ZHANG Liuping, ZENG Jianhui & YANG LeiBasin & Reservoir Research Center, university of petroleum, beijing 102249, china Key Laboratory for Hydrocarbon Accumulation Mechanism of Chinese Ministry of Education, university of petroleum, beijing 1 Basin and Reservoir Research Center University of Petroleum Beijing 102249 China Key Lab. Hydrocarbon Accumul. Mech. University of Petroleum Beijing 102249 China

With the newly obtained carbon isotope data for the natural gas, a pilot study of multiple-sourced alkanes related to the mantled-derived fluid is presented. The carbon isotope values of alkanes in the Dongying Sag possess the features indicating a general organic origin. However, there are two sub-populations in the isotopic data set, which reflect two specific types of origins. In general, the sub-population with high δ13CCH4 values is related to the CO2-rich, mantle-derived fluid, and it is distributed in the belts where mantle-derived fluid flow and basic volcanic activities have occurred. Geological and geochemical studies demonstrate that this variation of methane carbon isotope values in the Dongying Sag is unrelated with the basin bury and thermal histories, types of source rocks, and reactions between basin fluid and rocks. Mixing of mantle-derived fluid and organic sourced hydrocarbons is probably the cause for the variation.

关键词： mantle-derived fluid organic origin hydrocarbons in-teraction carbon isotope.

Preliminary study on the origin identification of natural gas by the parameters of light hydrocarbon

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Science china Earth Sciences 2008年第S1期51卷 131-139页

作者： HU GuoYi 1,2,3 ,LI Jian 1,2 ,LI Jin 1,2 ,LI ZhiSheng 1,2 ,LUO Xia 1,2 ,SUN QingWu 1,2 &MA ChengHua 1,2 1 Research Institute of petroleum Exploration and Development(Langfang Branch),Petrochina,Langfang 065007,china 2 The Key Laboratory of Gas Formation and Development,Petrochina,Langfang 065007,china 3 College of Geo-resources and information,china university of petroleum,beijing 102200,china Research Institute of petroleum Exploration and Development (Langfang Branch) Petrochina Langfang China The Key Laboratory of Gas Formation and Development Petrochina Langfang China College of Geo-resources and information China University of Petroleum Beijing China

The light hydrocarbon composition of 209 natural gas samples and individual light hydrocarbon carbon isotopes of 53 natural gas samples from typical humic-sourced gas and sapropelic-sourced gas in the four basins of china have been determined and *** identification parameters for humic-sourced gas and sapropelic-sourced gas are proposed or *** differences of compound-specificδ13C value of individual light hydrocarbon between humic-sourced gas and sapropelic-sourced gas have been *** humic-sourced gas has the distribution ofδ13C benzene > -24‰,δ13C toluene >-23‰,δ13C cyclohexane >-24‰andδ13C methyl cyclohexane >-24‰,while the sapropelicsourced gas has the distribution ofδ13C benzene 3C toluene 3C cyclohexane 3C methyl cyclohexane natural ***,it is suggested that the gas with relative content of nC7 of more than 30%and relative content of MCH of less than 70%is sapropelic-sourced gas,while gas with relative content of nC7 of less than 35%and relative content of MCH of more than 50%is humic-sourced *** components of C5-7 aliphatics, the gas with relative content of C5-7 normal alkane of more than 30%is sapropelic-sourced gas,while the gas with relative content of C5-7 normal alkane of less than 30%is humic-sourced *** paremeters have been suggested to identify humic-sourced gas and sapropelic-sourced gas.

关键词： natural gas humic-sourced gas sapropelic-sourced gas carbon isotope light hydrocarbon parameters

An introduction to Tsinghua Cloud

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Science china(information Sciences) 2010年第7期53卷 1481-1486页

作者： ZHENG WeiMin1,2 1Department of Computer Science and technology, Tsinghua university, beijing 100084, china 2Tsinghua National Laboratory for information Science and technology, beijing 100084, china Department of Computer Science and technology Tsinghua University Beijing China Tsinghua National Laboratory for information Science and technology Beijing China

Cloud computing has become a trend that draws attention from both academia and industry all over the world. This paper unveils details of Tsinghua Cloud, a comprehensive solution for cloud computing developed by Tsing... 详细信息

关键词： cloud computing distributed file system virtual computing environment data sharing

Synthesis of superheavy nuclei with ^(238)U target

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Science china(Physics,Mechanics & Astronomy) 2009年第10期52卷 1482-1488页

作者： LIU ZuHua1,3 & BAO JingDong2,4 1 Key Laboratory of Beam technology and Material Modification of Ministry of Education,beijing Normal university,beijing 100875,china 2 Department of Physics,beijing Normal university,beijing 100875,china 3 china Institute of Atomic Energy,beijing 102413,china 4 Center of Theoretical Nuclear Physics,National Laboratory of Heavy Ion Accelerator of Lanzhou,Lanzhou 730000,china Key Laboratory of Beam technology and Material Modification of Ministry of Education Beijing Normal University Beijing China china Institute of Atomic Energy Beijing China Department of Physics Beijing Normal University Beijing China Center of Theoretical Nuclear Physics National Laboratory of Heavy Ion Accelerator of Lanzhou Lanzhou China

The production of superheavy nuclei with Z=108-116 via hot fusion reactions of the neutron-rich projectiles with 238U target is systematically *** results show that the production cross sections of superheavy nuclei do not decrease monotonously as the atomic number Z *** cross sections of the superheavy nuclei at Z = 112 and 115 are enhanced as compared with the whole Z-trend in synthesis of the superheavy nuclei,which clearly illustrates that the reactions with large negative Q-value and shell correction are more favorable to synthesize superheavy nuclei.

关键词： superheavy nuclei fusion reaction cross section 238U target

The steady-state solution of dendritic growth from the undercooled binary alloy melt with the far field flow

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Science china(Technological Sciences) 2009年第8期52卷 2280-2287页

作者： CHEN MingWen1,2, WANG ZiDong2 & XU JianJun2,3,4 1 School of Applied Sciences, university of Science and technology beijing, beijing 100083, china 2 School of Materials Science and Engineering, university of Science and technology beijing, beijing 100083, china 3 School of Mathematical Sciences, Nankai university, Tianjin 300071, china 4 Department of Mathematics and Statistics, McGill university, Montreal H3A 2K6, Canada School of Applied Sciences University of Science and Technology Beijing Beijing China School of Materials Science and Engineering University of Science and Technology Beijing Beijing China School of Mathematical Sciences Nankai University Tianjin China Department of Mathematics and Statistics McGill University Montreal Canada

The steady-state dendritic growth from the undercooled binary alloy melt with the far field flow is considered. By neglecting the interface energy, interface kinetics and buoyancy effects in the system, we obtaine the steady-state solution for the case of the large Schmidt number, in terms of the multiple variable expansion method. The changes of the temperature and concentration fields, the morphology of the interface, the normalization parameter and the Peclet number of the system induced by uniform external flow are derived. The results show that, compared with the system of dendritic growth from undercooled pure melt, the convective flow in the system of growth from undercooled binary alloy has stronger effects on the morphology of the interface. Nevertheless, the shape of the interface still remains nearly a paraboloid.

关键词： binary alloy melt convection dendritic growth interfaces steady-state solution multiple variable expansion method

A new DNA algorithm to solve graph coloring problem

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Progress in natural Science:Materials International 2007年第6期17卷 733-738页

作者： Jiang Xingpeng1, Li Yin2, Meng Ya3 and Meng Dazhi2(1. National Laboratory of Pattern Recognition,Institute of Automation, Chinese Academy of Sciences, beijing 100080, china 2. College of Applied Sciences, beijing university of technology, beijing 100022, china 3. School of Science, beijing Institute of technology, beijing 100081, china) National Laboratory of Pattern Recognition Institute of Automation Chinese Academy of Sciences Beijing 100080 China College of Applied Sciences Beijing University of Technology Beijing 100022 China School of Science Beijing Institute of Technology Beijing 100081 China

Using a small quantity of DNA molecules and little experimental time to solve complex problems successfully is a goal of DNA computing. Some NP-hard problems have been solved by DNA computing with lower time complexity than conventional computing. However, this advantage often brings higher space complexity and needs a large number of DNA encoding molecules. One example is graph coloring problem. Current DNA algorithms need exponentially increasing DNA encoding strands with the growing of problem size. Here we propose a new DNA algorithm of graph coloring problem based on the proof of four-color theorem. This algorithm has good properties of needing a relatively small number of operations in polynomial time and needing a small number of DNA encoding molecules (we need only 6R DNA encoding molecules if the number of regions in a graph is R).

关键词： DNA computing NP-hard problem graph coloring problem.

Mechanism for calcite dissolution and its contribution to development of reservoir porosity and permeability in the Kela 2 gas field,Tarim Basin,china

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Science china Earth Sciences 2008年第4期51卷 567-578页

作者： YU BingSong1,3, DONG HailLiang2,3 & RUAN Zhuang1,3 1 State Key Laboratory of Geological Processes and Mineral resources, china university of Geosciences, beijing 100083, china 2 Department of Geology, Miami university,Oxford, OH 45056, USA 3 Geomicrobiology Laboratory, china university of Geosciences, beijing, 100083, china State Key Laboratory of Geological Processes and Mineral resources China University of Geosciences Beijing China Geomicrobiology Laboratory China University of Geosciences Beijing China Department of Geology Miami University Oxford USA

This study is undertaken to understand how calcite precipitation and dissolution contributes to depth-related changes in porosity and permeability of gas-bearing sandstone reservoirs in the Kela 2 gas field of the Tarim Basin, Northwestern china. Sandstone samples and pore water samples are col-lected from well KL201 in the Tarim Basin. Vertical profiles of porosity, permeability, pore water chem-istry, and the relative volume abundance of calcite/dolomite are constructed from 3600 to 4000 m below the ground surface within major oil and gas reservoir rocks. Porosity and permeability values are in-versely correlated with the calcite abundance, indicating that calcite dissolution and precipitation may be controlling porosity and permeability of the reservoir rocks. Pore water chemistry exhibits a sys-tematic variation from the Na2SO4 type at the shallow depth (3600-3630 m), to the NaHCO3 type at the intermediate depth (3630―3695 m),and to the CaCl2 type at the greater depth (3728―3938 m). The geochemical factors that control the calcite solubility include pH, temperature, pressure, Ca2+ concen-tration, the total inorganic carbon concentration (ΣCO2), and the type of pore water. Thermodynamic phase equilibrium and mass conservation laws are applied to calculate the calcite saturation state as a function of a few key parameters. The model calculation illustrates that the calcite solubility is strongly dependent on the chemical composition of pore water, mainly the concentration difference between the total dissolved inorganic carbon and dissolved calcium concentration (i.e., [ΣCO2] -[Ca2+]). In the Na2SO4 water at the shallow depth, this index is close to 0, pore water is near the calcite solubility. Calcite does not dissolve or precipitate in significant quantities. In the NaHCO3 water at the intermedi-ate depth, this index is greater than 0, and pore water is supersaturated with respect to calcite. Massive calcite precipitation was observed at this depth interval and

关键词： calcite dissolution porosity thermodynamic Tarim Basin

Estimation of underdetermined mixing matrix based on support vector machine

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Progress in natural Science:Materials International 2007年第11期17卷 1363-1367页

作者： Yang Zuyuan and Xie Shengli(School of Electrics & information Engineering, South china university of technology, Guangzhou 510641, china) School of Electrics and information Engineering South China University of Technology Guangzhou 510641 China

In underdetermined blind source separation (BSS), a novel algorithm based on extended support vector machine (SVM) is proposed to estimate the mixing matrix in this paper, including the number of the active sources. Instead of traditional clustering algorithms, it mainly takes the modulus of observations and the number in each direction of arrival, without any prior knowledge about the sources except for sparsity, and it is not sensitive to the initial values. Simulations are given to illustrate availability and robustness of our algorithm.

关键词： underdetermined BSS SVM clustering