检索结果-南通市图书馆

Journal of Mountain Science 2016年第9期13卷 1567-1583页

作者： hoppe Franziska ZhUSUI KYZY Taalaigul USUPBAEV Adilet SChICKhOFF Udo CEN Center for Earth System research and Sustainability Institute of Geography Laboratory of "Flora" Institute for Biology and Pedology National Academy of Sciences of the Kyrgyz Republic

rangelands occupy more than 80% of the agricultural land in Kyrgyzstan. At least 30% of Kyrgyz pasture areas are considered to be subject to vegetation and soil degradation. Since animal husbandry is the economic basis to sustain people＇s livelihoods, rangeland degradation presents a threat for the majority of the population. we present for the first time an ecological assessment of different pasture types in a remote area of the Naryn Oblast, using vegetation and softs as indicators of rangeland conditions. we analysed the current degree of utilization （grazing pressure）, the amount of biomass, soil samples, and vegetation data, using cluster analysis as well as ordination techniques. winter pastures （kyshtoo） are characterized by higher ph values （average of 7.27） and lower organic matter contents （average of 12.83%） compared to summer pastures （dzailoo） with average ph values of 6.03 and average organic matter contents of 21.05%. Additionally, summer pastures show higher above- ground biomass, and higher species richness and diversity. Our results support the hypothesis that winter pastures, which are located near settlements, suffer from over-utilisation, while the more distant summer pastures are subjected to much lower grazing pressure,

关键词： Alpine meadows Alpine steppes Animalhusbandry Classification Grazing management Montane pastures Ordination Plant communities

Liver transplantation and BCLC classification:Limitations impede optimum treatment

在线全文

学校读者我要写书评

暂无评论

hepatobiliary & Pancreatic Diseases International 2021年第1期20卷 6-12页

作者： Gerd Otto Michael B Pitton Maria hoppe-Lotichius Arndt weinmann (Former)Department of hepatobiliary and Transplant Surgery University Medical CenterMainzGermany Department of Diagnostic and Interventional radiology University Medical CenterMainzGermany Department of General Abdominal and Transplant SurgeryUniversity Medical CenterMainzGermany Department of Internal Medicine I University Medical CenterMainzGermany

Background:The Barcelona Clinic Liver Cancer(BCLC)system has been endorsed by international guidelines as a staging algorithm of hepatocellular *** analysis was performed to assess the outcome of liver transplantation in patients treated against the BCLC ***:The data of 198 patients who underwent liver transplantation for hepatocellular carcinoma were extracted from a prospectively maintained database to classify the patients according to the BCLC ***:BCLC staging was as follows:0,n=5;A,n=77;B,n=41;C,n=53;and D,n=***,liver transplantation was performed in the majority of patients against BCLC ***(n=16),radiofrequency ablation(n=15)and transarterial chemoembolization(n=151)preceded liver transplantation in 182 *** patients were transplanted without *** 1-,5-and 10-year survival rates were 83.8%,62.4%and 45.9%,and 1-,5-,and 10-year recurrence rates were 7.7%,22.7%and 26.7%.The BCLC classification did neither impact survival(P=0.796)nor recurrence(P=0.693).In the Cox analysis,rECIST tumor progression and initial alpha fetoprotein were independent predictors of ***:Neither the oncological nor the functional stratification imposed by the BCLC system was of importance for *** of flexibility and disregard of biological parameters hamper its clinical applicability in liver transplantation.

关键词： BCLC system Liver transplantation hepatocellular carcinoma Treatment

Numerical Simulation of Bubble Formation at a Single Orifice in Gas-fluidized Beds with Smoothed Particle hydrodynamics and Finite Volume Coupled Method

在线全文

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2015年第1期104卷 41-68页

作者： F.Z.Chen h.F.Qiang w.r.Gao 601 Staff room Xi’an Hi–Tech InstituteXi’anShanxiPRCPC 710025

A coupled method describing gas–solid two-phase flow has been proposed to numerically study the bubble formation at a single orifice in gas-fluidized *** particles are traced with smoothed particle hydrodynamics,whereas gas phase is discretized by finite volume *** force,gas pressure gradient,and volume fraction are used to couple the two *** effect of injection velocities,particle sizes,and particle densities on bubble growth is analyzed using the coupled *** simulation results,obtained for two-dimensional geometries,include the shape and diameter size of a bubble as a function of time;such results are compared with experimental data,previous numerical results,and other approximate model predictions reported in the ***,the flow profiles of gas and particle phases and the temperature distribution by the heat transfer model around the forming bubble are also *** results show that the coupled method efficiently describes of the bubble formation in fluidized *** proposed method is applicable for solving gas–solid two-phase flow in fluidization.

关键词： coupled method smoothed particle hydrodynamics finite volumemethod bubble formation heat transfer fluidization

Effect of environments and normal loads on tribological properties of nitrided Ni(45)(FeCoCr)(40)(AlTi)(15)high-entropy alloys

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2020年第7期42卷 85-96页

作者： L.w.Lan X.J.wang r.P.Guo h.J.Yang J.w.Qiao research Center for high-Entropy Alloys College of Materials Science and EngineeringTaiyuan University of TechnologyTaiyuan030024China

The tribological properties of nitrided Ni(45)(FeCoCr)(40)(AlTi)(15)high-entropy alloys(hEAs)were investigated in air and simulated acid rain under different normal loads(5,7,10,and 12 N)at ambient *** results revealed that as-cast hEAs were only composed of FCC phase,while the volume fraction of FCC phase in the nitrided alloys was significantly ***,the hard phases of AIN,CrN,Fe4 N,and TiN phases were formed in the nitrided *** thickness of the nitriding layer was about 8.4μ*** hardness increased from 8.7 GPa in as-cast alloys to 14.5 GPa in the nitrided *** addition,under the same conditions,the friction coefficient of the nitrided alloys was higher than that of as-cast alloys,but the wear rate was generally lower than that of as-cast ***,the wear rate of the nitrided alloys was the lowest in acid rain due to the lubrication,cleaning,and cooling in the liquid *** air,dominating wear mechanisms in as-cast and nitrided alloys were abrasive,delamination,and adhesive ***,the wear mechanism of as-cast and nitrided alloys in acid rain was mainly abrasive and corrosion wears.

关键词： Abrasive wear hardness Corrosive wear Microstructure wear mechanism

Effects of longwall-induced stress and deformation on the stability and mechanical integrity of shale gas wells drilled through a longwall abutment pillar

在线全文

学校读者我要写书评

暂无评论

International Journal of Mining Science and Technology 2017年第1期27卷 115-120页

作者： Daniel w.h.Su National Institute for Occupational Safety and health Bruceton 15236PAUSA

This paper presents the results of a comprehensive study conducted by CONSOL Energy, Marcellus Shale Coalition, and Pennsylvania Coal Association to evaluate the effects of longwall-induced subsurface deformations on the mechanical integrity of shale gas wells drilled over a longwall abutment *** primary objective is to demonstrate that a properly constructed gas well in a standard longwall abutment pillar can maintain mechanical integrity during and after mining operations. A study site was selected over a southwestern Pennsylvania coal mine, which extracts 457-m-wide longwall faces under about 183 m of cover. Four test wells and four monitoring wells were drilled and installed over a 38-m by84-m centers abutment pillar. In addition to the test wells and monitoring wells, surface subsidence measurements and underground coal pillar pressure measurements were conducted as the 457-m-wide longwall panels on the south and north sides of the abutment pillar were mined by. To evaluate the resulting coal protection casing profile and lateral displacement, three separate 60-arm caliper surveys were conducted. This research represents a very important step and initiative to utilize the knowledge and science obtained from mining research to improve miner and public safety as well as the safety and health of the oil and gas industries.

关键词： Gas well Casing Abutment pillar Stability Safety and health Instrumentation Numerical simulation

A Conflict Study of Chinese Construction Project Multicultural Teams

在线全文

学校读者我要写书评

暂无评论

A Conflict Study of Chinese Construction Project Multicultur...

作者： Brittany hoppe 山东大学

学位级别：硕士

Conflicts within construction project teams are virtually inevitable as construction project teams face severe pressure to execute their projects within the binds of the triple-constraint triangle（meeting time,cost,and quality expectations）.In alignment with The Belt and road Initiative,Chinese construction companies are executing many construction endeavors abroad and continue to seek overseas construction and infrastructure project *** abroad in a foreign environment can be confusing for many Chinese companies as’business as usual’often simply does not *** addition to the new rules and customs within the foreign country,managing and participating in a multicultural construction project team has its own great challenges and these challenges can result in conflicts if they are not managed *** unnecessary conflicts leads to more time and energy being allocated on the construction project and project tasks rather than using these valuable resources on issues and conflict *** importance of using time and energy efficiently in projects emphasizes the importance of studying conflicts in multicultural construction project *** purpose of this research study was to identify the influencing factors that lead to conflicts and study their relationship quantitatively through the development of a Partial Least Squares Equation Modeling（PLS-SEM）*** findings suggested a number of factors that lead to conflicts and after these were analyzed,mechanisms to reduce conflicts and improve project team environments were *** is also suggested that further research into conflict in construction project teams should consider looking at construction conflicts in different countries and with participants of different *** research is still needed to figure out what other factors result in ineffective issue management and lead to conflicts in multicultural construction project teams under the jurisdictio

关键词：

Design, simulation and construction of the Taban tokamak

同方学位论文库评论

在线全文

同方学位论文库

学校读者我要写书评

暂无评论

Plasma Science and Technology 2018年第4期20卷 112-120页

作者： h r MIrZAEI r AMrOLLAhI Statistics of Department of Energy Engineering & Physics Amirkabir University of Tehran Tehran lran

This paper describes the design and construction of the Taban tokamak, which is located in Amirkabir University of Technology, Tehran, Iran. The Taban tokamak was designed for plasma investigation. The design, simulation and construction of essential parts of the Taban tokamak such as the toroidal field(TF) system, ohmic heating(Oh) system and equilibrium field system and their power supplies are presented. For the Taban tokamak, the toroidal magnetic coil was designed to produce a maximum field of 0.7 T at r?=?0.45 m. The power supply of the TF was a130 kJ, 0–10 kV capacitor bank. ripples of toroidal magnetic field at the plasma edge and plasma center are 0.2% and 0.014%, respectively. For the Oh system with 3 kA current, the stray field in the plasma region is less than 40 G over 80% of the plasma volume. The power supply of the Oh system consists of two stages, as follows. The fast bank stage is a 120 μF, 0–5 k V capacitor that produces 2.5 kA in 400 μs and the slow bank stage is 93 mF, 600 V that can produce a maximum of 3 kA. The equilibrium system can produce uniform magnetic field at plasma volume. This system’s power supply, like the Oh system, consists of two stages, so that the fast bank stage is 500 μF, 800 V and the slow bank stage is 110 mF, 200 V.

关键词： tokamak magnetic field equilibrium

SIMULATION OF ThE MAGNETIZATION rEVErSAL PrOCESS OF rECTANGLE-ShAPED NiFe FILM ELEMENTS UNDEr AN OrThOGONAL MAGNETIC FIELD

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2005年第5期18卷 642-646页

作者： w.L. Zhang r.J. Tang w.X. Zhang B. Peng h. C. Jiang h.w. Zhang School of Microelectronics and Solid-state Electronics University of Electronic Science and Technology of China Chengdu 610054 China

The magnetization reversal process of nano-size rectangle-shaped NiFe film elements with different aspect ratios have been investigated under the orthogonally applied magnetic fields by micromagnetic simulation. Different magnetization reversal modes can appear depending on whether the bias field is applied or not. when there is no bias field, double “C” state is the initial reversal state. however, when there is a bias field, “S” state is the starting mode. The larger the aspect ratio is, the larger the switching field is. But, when the aspect ratio is larger than 3, the increase of the switching field ceases. These results can provide useful information to the application of the patterned NiFe film with rectangular elements.

关键词： NiFe film element micromagnetics aspect ratio magnetization reversal,switching field

Q-Switching Pulse Operation in 1.5-μm region Using Copper Nanoparticles as Saturable Absorber

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2017年第3期34卷 41-44页

作者： A.r.Muhammad M.T.Ahmad r.Zakaria h.r.A.rahim S.F.A.Z.Yusoff K.S.hamdan h.h.M.Yusof h.Arof S.w.harun Department of Electrical Engineering Faculty of EngineeringUniversity of MalayaKuala Lumpur 50603Malaysia Photonics research Centre Physics DepartmentFaculty of ScienceUniversity of MalayaKuala Lumpur 50603Malaysia

we demonstrate a passively Q-switched erbium-doped fiber laser （EDFL） using a copper nanoparticle （CuNP） thin film as the saturable absorber in a ring cavity. A stable Q-switched pulse operation is observed as the CuNP saturable absorber （SA） is introduced in the cavity. The pulse repetition rate of the EDFL is observed to be proportional to the pump power, and is limited to 101.2khz by the maximum pump power of 113.7mw. On the other hand, the pulse width reduces from 10.19μs to 4.28μs as the pump power is varied from 26.1 mw to 113.7mw. The findings suggest that CuNP SA could be useful as a potential saturable absorber for the development of the robust, compact, efficient and low cost Q-switched fiber laser operating at 1.5-μm region.

关键词： Cu m region Using Copper Nanoparticles as Saturable Absorber Q-Switching Pulse Operation in 1.5 SA khz EDF

Effect of solute atom concentration and precipitates on serrated flow in Mg-3Nd-Zn alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2018年第7期34卷 1236-1242页

作者： w.h.wang D.wu r.S.Chen X.N.Zhang State Key Laboratory of Metal Matrix Composites School of Materials Science and Engineering Shanghai Jiao Tong University The Group of Magnesium Alloys and Their Applications Institute of Metal Research Chinese Academy of Sciences

Influence of solute atom concentration and precipitates on serrated flow, i.e., Portevin-Le Chatelier effect, was studied in Mg-3Nd-Zn alloy by tensile test at 250℃ with a strain rate of l x 10^-3 s^-1 Microstructure and tensile property of the Mg-3Nd-Zn alloy in solution and aging conditions were also investigated. results indicate that the serrated flow was weakened with aging time, and geometry of the serrations changed from sharp to rounded corner. Through analyzing the mechanism of the interactions between dislocations and solute atoms, it was identified that the precipitates did not only weaken the serrated flow due to the decrease in the concentration of solute atom, but also regulate the serration type by restraining the movement of dislocations during high temperature deformation.2017 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science ＆ Technology.

关键词： Magnesium alloy Serrated flow Precipitate heat treatment Deformation behavior