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NUMERICAL SIMULATION FOR SHALLOW FLOW AND POLLUTANT DISPERSION BASED ON QUAD-TREE MESHES

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Journal of Hydrodynamics 2006年第2期18卷 161-169页

作者： LIU Xiao-dong hua Zu-lin State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow LakesCollege of Environmental Science and Engineering Hohai UniversityNanjing 210098 China

A 2D depth-averaged flow-pollutant coupled model based on quad-tree meshes was established to accurately simulate flows in water areas with irregular natural boundaries in this paper. The grids were generated by recursive subdivision about seeding points. A new neighbor-finding algorithm was presented. The governing equations were discrctized in collocated conservative variables by using the finite volume method, and the normal flux of mass, momentum and pollutants across the interlace between cells were computed by a Godunov-type Flux Difference Splitting （FDS） scheme. The model was applied to simulate flow fields around a groin. The computed values are in agreement with observed data. The results indicate that quad-tree meshes have fine local resolution, high efficiency and easy local refinement. It is clear that the quad-tree grid model can offer gains in efficiency when applied to complex flow domains or strong shear flows. Finally the model is applied to flow fields and concentration fields simulation in Jiangsu Haizhou Bay. The simulated polluted area is matched well with observations. Therefore, this model can be used to predict flow and concentration fields of actual water area with irregular natural land boundaries.

关键词： quad-tree grid shallow flow numerical simulation dispersion Godunov-type

Influence of Interfacial Diffusion on Mechanical Property of Vacuum Fusion Sinter (VFS) WC-Co Composite Coating

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Journal of Iron and Steel Research International 2006年第2期13卷 69-72页

作者： huaNG Xin-bo FAN Kang-qi SUN Qin-dong LIN hua-chun JIA Jian-yuan School of Electromechanical Engineering Xi＇an University of Engineering Science and Technology Xi＇an 710048 Shaanxi China School of Electrical Engineering Xi＇an Jiaotong University Xi＇an 710049 Shaanxi China School of Electromechanical Engineering Xidian University Xi＇an 710071 Shaanxi China School of Computer Science and Engineering Xi＇an University of Technology Xi＇an 710049 Shaanxi China School of Electromechanical Engineering Qingdao Technological University Qingdao 266033 Shandong China

The WC-Co composite coatings bonded tightly to steel substrate have been made by vacuum fusion sinter （VFS）. The concentration distribution of some components were measured by the electron probe, and the microstructure and morphology of VFS coatings were observed and analyzed by SEM, X-ray diffractometer and microhardness tester. Diffusion coefficient of every element was calculated by using the experimental results. The influence of the interracial diffusion on the microstructure, Vickers hardness and interracial bond strength of the VFS coatings was studied in detail. The experimental results show that there is a metallurgical bond area between the VFS WC-Co coatings and the steel substrate. The VFS coatings are characterized by the gradient hardness of the interface and the high bond strength to the steel substate, both of which are beneficial to the improvement of the wear resistance and corrosion resistance.

关键词： vacuum fusion sintering WC-Co composite coating interracial diffusion bond strength

Rapid Synthesis of Size-controlled Gold Nanoparticles by Complex Intramolecular Photoreduction

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Chemical Research in Chinese Universities 2007年第5期23卷 500-504页

作者： dong Shou-an YANG Sheng-chun TANG chun Kunming Institute of Precious Metals Kunming 650221 P. R. China

A rapid synthesis of size-controlled gold nanoparticles was *** method is based on the sensitive intramolecular photoreduction reaction of Fe（Ⅲ）-EDTA complex in chloroacetic acid-sodium acetate buffer solution,where Fe（Ⅱ）-EDTA complex generated by photo-promotion acts as a reductant of AuCl-4 *** nanoparticles formed were stabilized by EDTA ligand or other protective agents *** a result,well-dispersed gold nanoparticles with an average diameter range of 6.7 to 50.9 nm were *** to the characterizations by the UV spectrum and TEM,the intramolecular charge transfer of the excited states of complex Fe（Ⅲ）-EDTA and the mechanism of forming gold nanoparticles were discussed in detail.

关键词： Gold nanoparticle Synthesis Intramolecular photoreduction Fe ( Ⅲ ) -EDTA complex

CDM: Content Diffusion Model for Information-Centric Networks

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Journal of Computer Science & Technology 2021年第6期36卷 1431-1451页

作者： Bo Chen Liang Liu hua-dong Ma Beijing Key Laboratory of Intelligent Telecommunications Software and Multimedia Beijing University of Posts and TelecommunicationsBeijing 100876China School of Computer Science Beijing University of Posts and TelecommunicationsBeijing 100876China

This paper proposes the Content Diffusion Model(CDM)for modeling the content diffusion process in information-centric networking(ICN).CDM is inspired by the epidemic model and it provides a method of theoretical quantitative analysis for the content diffusion process in ***,CDM introduces the key functions to formalize the key factors that influence the content diffusion process,and thus it can construct the model via a simple but efficient ***,we derive CDM by using different combinations of those key factors and put them into several typical ICN scenarios,to analyze the characteristics during the diffusion process such as diffusion speed,diffusion scope,average fetching hops,changing and final state,which can greatly help to analyze the network performance and application design.A series of experiments are conducted to evaluate the efficacy and accuracy of *** results show that CDM can accurately illustrate and model the content diffusion process in ICN.

关键词： information-centric networking content diffusion modeling

Population Synthesis for Mira Variables

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Chinese Journal of Astronomy and Astrophysics 2005年第4期5卷 419-425页

作者： chun-hua Zhu Chao-Zheng Zha Department of Physics Xinjiang University Urumqi 830046

By means of a population synthesis code, we investigate the Mira variables. Their birth rate （over 0.65yr^-1） and their number （～ 130000） in the Galaxy are estimated. For all possible Mira variables, ranges of their initial masses,pulsating periods, mass losses and lifetimes are given. We check our model with the observed Mira variables near the Sun and our results prove to be valid.

关键词： stars: late-type - stars: variables - stars: fundamental parameters

Effects of daily telephone-based re-education before taking medicine on Helicobacter pylori eradication: A prospective single-center study from China

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World Journal of Gastroenterology 2015年第39期21卷 11179-11184页

作者： chun-hua Wang Sheng-Tao Liao Jun Yang chun-Xia Li Ying-Ying Yang Ran Han dong-Feng Chen chun-Hui Lan Department of Gastroenterology Daping Hospital the Third Military Medical University Cadet Brigade the Third Military Medical University Department of Gastroenterology Guizhou Aerospace Hospital

AIM: To investigate the effects of daily telephonebased re-education(TRE) before taking medicine for the eradication of Helicobacter pylori(H. pylori) on the compliance and the eradication rate in a Chinese patient *** : Aprospective, physician-blind e d, randomized, controlled clinical study was conducted. The patients were randomly assigned to receive TRE every day before taking medicine(TRE group) or no TRE(control group). The patients in the TRE group received regular instructions before taking medicine for the eradication of H. pylori during the entire courseof treatment through telephone calls. The patients in the control group received detailed instructions at the time of seeing a doctor for the guidance. The primary outcome was the H. pylori eradication rate after treatment. The secondary outcomes included the clinical remissions after treatment, adverse events, compliance, and patients' ***: A total of 140 patients were randomized, 70 to the TRE group and 70 to the control group. As the primary outcome, the H. pylori eradication rates in the TRE and control groups were 62.7% and 71.2% in per protocol analysis(P = 0.230), and 52.9% and 52.9% in intention-to-treat analysis(P = 0.567), respectively. As the secondary outcomes, there were no significant differences in the patients' satisfaction between the two groups(good, 79.7% vs 76.9%; fair, 13.6% vs 19.2%; poor, 6.7% vs 3.9%, for the TRE group and control group, respectively; P > 0.05 for all); the rates of adverse effects were 15.2% and 63.5% in the TRE and control groups, respectively(P < 0.001); the compliance rates in the TRE and control groups were 85.7% and 74.3%, respectively(P = 0.069).CONCLUSION: Daily TRE before taking medicine had no significant impact on the patients' compliance, satisfaction, or H. pylori eradication, but reduced the rate of adverse events.

关键词： Helicobacter pylori Eradication Telephone re-educa

Effect of projectile parameters on opening behavior of PELE penetrating RC target

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Defence Technology（防务技术） 2021年第3期17卷 859-873页

作者： Li-zhi Xu Cheng-xin Du chun Cheng Xiao-dong Wang Jiang-bo Wang Zhong-hua Du Guang-fa Gao School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing210094China

When a penetrator with enhanced lateral effect(PELE) impacts on a reinforced concrete(RC) target,the target is damaged with a large *** understanding of how PELE projectile parameters affect the opening dimension,is essential for effective design of the PELE *** this study,under the condition that the impact velocity and target parameters(strength and thickness) were fixed values,the important influence factors of the PELE(jacket wall thickness B,jacket material strength Y1,filling material strength Y2 and angle of monolithic jacket θ) were determined by a dimensional *** and simulations of the PELE penetrating the RC target were conducted to analyze the influence of these factors on opening diameter(D,an equivalent diameter under relative kinetic energy).Based on the test and simulation results,it is found that the influence of these factors B,Y1 and θ on the deformation mode of the jacket shows a similar trend:as values of the three factors decrease,the jacket deforms from small bending deformation to large one,and then to curling *** causes the opening diameter to first increase with the decrease of these three factors,and then *** is well known that the bending resistance of the jacket is related to these factors B,Y1 and θ.Therefore,a plastic limit bending moment(M0) of the jacket was quoted to characterize the influence of these factors on the bending deformation of the jacket and the opening diameter of the *** influence factor Y2 causes D to first increase with the increase of Y2,and then decreases.A formula was developed to predict the opening diameter,whose influence parameters were considered in a dimensionless *** has been shown that the dimensionless opening diameter D/d1 is dependent on two dimensionless parameters■ and■,where d1 and fc are the outer diameter of the projectile and the compressive strength of the target,respectively.

关键词： Penetrator with enhanced lateral effect Opening behaviour Reinforced concrete target Dimensional analysis

Study on explosion process of methane-coal dust mixture

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Journal of Coal Science & Engineering(China) 2013年第3期19卷 332-336页

作者： Guang-dong GONG chun-hua BAI Qing-Ming LIU China Ordnance Industrial Standardization Research Institute Beijing 100089 China Beijing Institute of Technology Beijing 100081 China

The experimental system of 10 m3 large-scale multiphase combustion explosion tank was used for research into the explosion development process under the ignition conditions of methane-coal dust-air mixture, and the overpressure development processes of the mixture at different distances were obtained. For the methane-coal dust-air mixture with an equivalence ratio of 1, the explosion pressure and pressure rise rate reached their maximum under a methane concentration of 8% and a coal dust concentration of 25 g/m3, while the maximum explosion pressure and pressure rise rate both occurred 0.5 m away from the ignition point under a methane concentration of between 4.5% and 8%, and a coal dust concentration of between 25 g/m3 and 1 O0 g/m3. Moreover, the greater the explosion intensity of mixture, the closer the occurrence location of maximum overpres- sure was to the ignition source.

关键词： methane coal dust explosion

行距配置和种植密度对棉花干物质生产及产量的影响

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作物学报 2025年第1期51卷 221-232页

作者：辛明华秘雅迪王国平李小飞李亚兵董合林韩迎春冯璐中国农业科学院棉花研究所/棉花生物学国家重点实验室河南安阳455000 中国农业科学院西部农业研究中心新疆昌吉831100

行距配置和种植密度是影响棉花产量和品质的重要因素。当前新疆棉花种植主要采用宽窄行配置,也有等行距配置方式,但对这两种方式的认识尚存在争议。为此,本研究以中棉所88号为供试材料,采用裂区设计,行距配置(等行距和宽窄行)为主区,种... 详细信息

行距配置和种植密度是影响棉花产量和品质的重要因素。当前新疆棉花种植主要采用宽窄行配置,也有等行距配置方式,但对这两种方式的认识尚存在争议。为此,本研究以中棉所88号为供试材料,采用裂区设计,行距配置(等行距和宽窄行)为主区,种植密度12×104株hm^(–2) (D1)、16×104株hm^(–2) (D2)和18×104株hm^(–2) (D3)为裂区,开展了2年大田试验,比较研究了行距配置和密度对棉花群体生长发育、干物质积累和分配、以及产量和纤维品质的影响。结果表明,中等密度(16×10^(4)株hm^(–2))下等行距和宽窄行处理组合的叶面积指数(LAI)增速、LAI峰值,以及吐絮期生殖器官生物量的分配比例均高于其他处理组合,且二者无显著差异。各处理组合间的棉花群体生长率(CGR)、净同化率(NAR)和棉铃生长率(BGR)均无显著差异。2年平均,中等密度下等行距和宽窄行处理组合的籽棉产量相当,纤维品质指标也无显著差异。表明在中等密度下,无论采用等行距还是宽窄行种植模式,均能达到理想的产量和品质。本研究为新疆棉花行距配置和密度选择提供了科学依据。

关键词：棉花单双行配置密度生长指标干物质积累与分配产量及品质