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纳米硫酸钡的制备工艺及其应用

山东化工 2004年第6期33卷 23-25页

作者：霍红欧阳朝斌刘有智中北大学化学工程系山西太原030051 中国科学院过程工程研究所北京100080

纳米级硫酸钡具有高比表面、高活性、分散性能好等特殊性能 ,在塑料、高档油漆等领域有广泛的应用前景 ,本文系统地介绍了目前普通硫酸钡及纳米硫酸钡的制备工艺 ,并对比地介绍了普通硫酸钡和纳米硫酸钡的应用。

关键词：纳米硫酸钡制备工艺应用

The formation process and cloud physical characteristics for a typical downburstproducing thunderstorm in beijing

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chinese Science Bulletin 2003年第S2期48卷 77-82页

作者： GUO Xueliang FU Danhong institute of Almospherie Physics, chinese academy of sciences, beijing 100029. china chinese Acad Sci Inst Atmospher Phys Beijing 100029 Peoples R China

The formation process and characteristics ofcloud physical structure of a severe thunderstorm accompa-nied with strong wind on 23 August, 2001 in beijing wasstudied using PSU/NCAR mesoscale model ( MM5) couplingwith a severe storm model with hail-bin microphysics. Theresults show that the specific topography and distributionfeatures of cold/warm current in the beijing region playedprominent roles in forming, developing and maintaining thesevere storm. Due to solar radiation heating and topographiclifting, the convective cells were easily formed when thewesterly airflow passed over high mountainous regions inbeijing. The warm and wet air entered the cloud from itsfrontage and enhanced the convection, and formed a largeamount of graupel/hail particles at the middle and upperportion of the clouds. The precipitation was primarilyformed due to melting of graupel/hail particles. The strongdowndraft was mainly produced by negative buoyancy dueto loading, melting of graupel/hail particles as well asevaporative cooling of rain water. The divergent airflow in-duced by the strong downdraft led to the disastrous burstwinds at the surface and also forced lifting of warm and wetairflow in the moving direction of the storm and formed newclouds that further promoted and maintained the storm de-velopment.

关键词： beijing region thunderstorm and disastrous wind cluud physical features.

chinese national clinical practice guidelines on the prevention,diagnosis,and treatment of early gastric cancer

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chinese Medical Journal 2024年第8期137卷 887-908页

作者： Peng Li Ziyu Li Enqiang Linghu Jiafu Ji Society of Digestive Endoscopy of the chinese Medical Association Colorectal Surgery Group of the chinese Medical Association chinese Association of Gastroenterologists&Hepatologists National Clinical Research Center for Digestive Diseases chinese Medical Journal Clinical Practice Guideline Collaborative Department of Gastroenterology Beijing Friendship HospitalCapital Medical UniversityNational Clinical Research Center for Digestive DiseaseBeijing 100050China Department of Gastrointestinal Surgery Key Laboratory of Carcinogenesis and Translational Research(Ministry of Education)Peking University Cancer Hospital and InstituteBeijing 100142China Department of Gastroenterology and Hepatology the First Medical CenterChinese People’s Liberation Army General HospitalBeijing 100853China 不详

Background:Gastric cancer is one of the most common malignant tumors in the digestive system in *** comprehensive practice guidelines for early gastric cancer in china are currently ***,we created the chinese national clinical practice guideline for the prevention,diagnosis,and treatment of early gastric ***:This clinical practice guideline(CPG)was developed in accordance with the World Health Organization’s recommended process and with the Grading of Recommendations Assessment,Development,and Evaluation(GRADE)in assessing evidence *** used the Evidence to Decision framework to formulate clinical recommendations to minimize bias and increase transparency in the CPG development *** used the Reporting Items for practice Guidelines in HealThcare(RIGHT)statement and the Appraisal of Guidelines for Research and Evaluation II(AGREE II)as reporting and conduct guidelines to ensure completeness and transparency of the ***:This CPG contains 40 recommendations regarding the prevention,screening,diagnosis,treatment,and follow-up of early gastric cancer based on available clinical studies and *** provide recommendations for the timing of Helicobacter pylori eradication,screening populations for early gastric cancer,indications for endoscopic resection and surgical gastrectomy,follow-up interval after treatment,and other ***:This CPG can lead to optimum care for patients and populations by providing up-to-date medical *** intend this CPG for widespread adoption to increase the standard of prevention,screening,diagnosis,treatment,and follow-up of early gastric cancer;thereby,contributing to improving national health care and patient quality of life.

关键词： Early gastric cancer Prevention Screening Diagnosis Treatment Follow-up

A new approach of cascade utilization of the chemical energy of fuel

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Progress in Natural Science:Materials International 2006年第5期16卷 518-523页

作者： HAN Wei, JIN Hongguang and LIN Rumou ( institute of engineering Thermophysics, chinese academy of sciences, beijing 100080, china Graduate School of the chinese academy of sciences, beijing 100080, china) institute of engineering Thermophysics Chinese Academy of Sciences Beijing 100080 China Graduate School of the chinese academy of sciences Beijing 100080 China

The indirect release of chemical energy of fuel is investigated, and a new mechanism is proposed to identify the cascade utilization of chemical energy of fuel more clearly. Based on the concept of energy level, the internal phenomenon of the indirect chemical energy release is disclosed, and the equations of energy level describing the utilization of chemical energy and thermal energy during the indirect chemical energy release process are obtained. From theoretical analysis, we find that the superiority of the indirect chemical energy release of fuel comes from the cascade utilization of the fuel's chemical energy. Moreover, the cascade utilization of chemical energy is verified by the investigation of CRGT (chemically recuperated gas turbine). As a result, the thermal exergy obtained from the chemical energy release of fuel increases by 2 % -3 % . The results obtained here may help a deeper understanding of indirect chemical energy release of fuel and provide a theoretical basis for the synthesis of innovative energy systems.

关键词： chemically recuperated gas turbine methane/steam reforming chemical energy level cascade utilization.

Structures and physical properties of rigid polyurethane foams with water as the sole blowing agent

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Science china Chemistry 2006年第4期49卷 363-370页

作者： LI Xiaobin1,2, CAO Hongbin1 & ZHANG Yi1 1. institute of process engineering, chinese academy of sciences, beijing 100080, china 2. Graduate School of the chinese academy of sciences, beijing 100039, china institute of process engineering Chinese Academy of Sciences Beijing China Graduate School of the chinese academy of sciences Beijing China

Rigid polyurethane foams blown by varying water level were prepared in this study. The structures and physical properties of rigid polyurethane foams blown by water were measured with FT-IR, universal testing machine (Instron3365), scanning electron microscope (SEM) and differential scanning calorimeter (DSC). The results show that polyurea and polybiuret were the typical charac- teristics, and the cream time and gel time were shorter for the fully water blown rigid foams than that for the fully cyclopentane blown foams. The density of foam samples decreased from 45.0 kg/m3 to 27.4 kg/m3 with the increase of water level from 3 pph to 7 pph. Compressive strength exhibited the similar behavior with density. The average cell size of foam samples ranged from 241 μm to 356 μm with the increase of water level from 3 pph to 7 pph, respectively. At the same time, poorer dimen- sional stability was encountered with the increase of average cell size due to fast diffusion rate of CO2 out of the foam. The results of thermal analysis show that the glass transition temperature (Tg) shifted to a higher temperature with the increase of isocyanate level when more water was used as chemical blowing agent.

关键词： polyether polyol, polyurethane rigid foam, compressive strength, dimensional stability, cell size, glass transition temperature.

Effect of concentration on surfactant micelle shapes——A molecular dynamics study

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Science china Chemistry 2005年第5期48卷 470-475页

作者： GAO Jian1,2, GE Wei1 & LI Jinghai1 1. Multiphase Reaction Laboratory, institute of process engineering, chinese academy of sciences, beijing 100080, china 2. Graduate School of The chinese academy of sciences, beijing 100085, china Multiphase Reaction Laboratory Institute of Process Engineering Chinese Academy of Sciences Beijing China Graduate School of The chinese academy of sciences Beijing China

Many aspects of the behavior of surfactants have not been well understood due to the coupling of many different mechanisms. Computer simulation is, therefore, attractive in the sense that it can explore the effect of different mechanisms separately. In this paper, the shapes, structures and sizes of sodium dodecylbenzenesulfonate (SDBS) micelles under different con-centrations in an oil/water mixture were studied via molecular dynamics (MD) simulations using a simplified atomistic model which basically maintains the hydrophile and lipophile properties of the surfactant molecules. Above the critical micellar concentration (cmc), surfactant molecules ag-gregate spontaneously to form a wide variety of assemblies, from spherical to rodlike, wormlike and bilayer micelles. Changes in their ratios of the principle moments of inertia (g1/g3, g2/g3) in-dicated the transition of micelle shapes at different concentrations. The aggregation number of micelle is found to have a power-law dependence on surfactant concentration.

关键词： surfactant, MD simulation, sodium dodecylbenzenesulfonate, micelle shape.

Pseudo-particle simulation of multi-scale heterogeneity in fluidization

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chinese Science Bulletin 2003年第7期48卷 634-636页

作者： GE Wei, ZHANG Jiayuan, LI Tinghua & LI Jinghai institute of process engineering, chinese academy of sciences, beijing 100080, china institute of process engineering Chinese Academy of Sciences Beijing 100080 China

Fluidization is a process of wide application, but its dynamic behavior is not well understood because of its multi-scale heterogeneity and regime multiplicity which are difficult to simulate in traditional numerical methods. By discretizing the fluid phase into a large number of interactive simple particles, which can incorporate many-body moving boundaries easily, pseudo-particle modeling (PPM) has re-produced reasonable radial and axial heterogeneity on macro-scale as well as solids clustering and fluid flows on meso- and micro-scales. The simulation suggests a consistent evolution of the complexity across different scales with itself serving as an ideal exploring tool.

关键词：流化作用杂质拟粒子模型化粒子法拟粒子仿真

Electrochemical studies of nickel deposition from aqueous solution in super-gravity field

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Science china(Technological sciences) 2007年第1期50卷 39-50页

作者： GUO ZhanCheng1,2, GONG YingPeng2 & LU WeiChang2 1 Metallurgical & Ecological School, University of Science and Technology, beijing 100083, china 2.institute of process engineering, chinese academy of sciences, beijing 100080, china Metallurgical & Ecological School University of Science and Technology Beijing China institute of process engineering Chinese Academy of Sciences Beijing China

The effect of super-gravity on electrochemical deposition of nickel from aqueous solution was studied. The SEM pictures show that the microstructure of nickel film deposited under the super-gravity condition is finer and more uniform compared with that obtained in normal gravity condition, and the crystal grains diminish with the increase of super-gravity coefficient. The XRD patterns indicate that the ar-rangement of crystalline grains of nickel film deposited under the super-gravity field is more regular, and the crystalline grain sizes decrease with the increase of super-gravity coefficient. Toughness, tensile stress and hardness of the nickel film are markedly raised with the increase of super-gravity coefficient, and hydrogen content in the nickel film decreases with the increase of super-gravity coefficient. From the polarization curves of hydrogen evolution reaction under the su-per-gravity condition, a significant reduction of over-potential on electrode was found when current density increased. The process of hydrogen evolution reaction was enhanced under the super-gravity condition. The electro-deposition rate, the microstructure and properties of deposited nickel film under super-gravity condi-tion were still affected by the relative orientation between inertia force and depos-iting surface. It is favorable to gain the nickel film with better mechanic properties when inertia force orientates vertically towards depositing surface.

关键词： super-gravity electrochemistry electro-deposition nickel film

Software engineering Technology for the 21^(st) Century

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Wuhan University Journal of Natural sciences 2001年第Z1期6卷 152-158页

作者： Cheng Hu institute of Software, chinese academy of sciences beijing 100080, china institute of Software Chinese Academy of Sciences Beijing China

In this paper we will discuss the software engineering technology for the 21 st century. First we review development over the last half century, overview application requirement and environment, accept a challenge. Then we outline following software engineering techniques: 1) process;2) Analysis;3) Design;4) UML;5) Component;6) Java +XML;7) Integrated;8) Quality(ISO9000&CMM).

关键词： software engineering object oriented component Java UML CMM ISO9000