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Waterways structural optimum design of electric car radiator 被引量:1
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作者 FAN Bailin CHEN hua +1 位作者 ZHANG Pei DOU Jinping 《Computer Aided Drafting,Design and Manufacturing》 2012年第2期39-41,共3页
Thermal resistance was composed by thermal resistance of Aluminum substrate, thermal resistance of convective heat transfer and the thermal resistance of the cooling liquid. The change rule was studied through the cal... Thermal resistance was composed by thermal resistance of Aluminum substrate, thermal resistance of convective heat transfer and the thermal resistance of the cooling liquid. The change rule was studied through the calculation on Aluminum plate thermal resistance, thermal resistance of convective heat transfer and the thermal resistance of the cooling liquid. Its change regular- ity was simulated by toolbox In the MATLAB, and it was found that thermal resistance of convective heat transfer effect on the effi- ciency was most obvious in a certain amount of the heat and flow for thermal resistance of the Pin-fin radiator under the premise. The structural parameters of radiator were related to the size of thermal resistance. 展开更多
关键词 RADIATOR convective heat transfer thermal resistance optimum design
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具有修正的Min(N,D)-策略和单重休假的Geo/G/1离散时间排队分析
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作者 魏瑛源 余玅妙 唐玉玲 《应用数学》 北大核心 2026年第1期108-128,共21页
本文研究服务员具有单重休假和系统采用修正的Min(N,D)-策略的离散时间Geo/G/1排队系统,运用更新过程理论、全概率分解技术和z-变换工具,从任意初始状态开始,研究队长的瞬时性态和平稳性态,得到了任意时刻n^(+)处队长瞬态分布的z-变换... 本文研究服务员具有单重休假和系统采用修正的Min(N,D)-策略的离散时间Geo/G/1排队系统,运用更新过程理论、全概率分解技术和z-变换工具,从任意初始状态开始,研究队长的瞬时性态和平稳性态,得到了任意时刻n^(+)处队长瞬态分布的z-变换表达式和稳态分布的递推表达式,同时给出了不同时刻n^(-)、n、n^(+)和外部观测点处队长稳态分布之间的重要关系.进一步借助于数值实例,讨论了系统的空闲率与稳态平均队长关于系统参数的敏感性,并且阐述了便于作数值计算的队长稳态分布的递推公式在系统容量优化设计中的重要价值.最后,运用更新报酬过程定理,建立了费用结构模型,获得了系统长期运行下单位时间内所产生的期望费用的显示表达式,并通过数值算例,寻求使期望费用最小的最优控制策略(N^(*),D^(*)). 展开更多
关键词 离散时间排队 修正的Min(N D)-策略 单重休假 队长分布 系统容量优化设计 最优控制策略
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Decision-making of Aircraft Optimum Configuration Utilizing Multidimensional Game Theory 被引量:1
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作者 彭润艳 王和平 +1 位作者 王正平 林宇 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2010年第2期194-197,共4页
As multi-discipline coupling and components interference often affect the aircraft configuration decision-making and analysis during conceptual design process, this article presents an approach of multidimensional gam... As multi-discipline coupling and components interference often affect the aircraft configuration decision-making and analysis during conceptual design process, this article presents an approach of multidimensional game theory based on aircraft compo- nents to deal with this problem. The idea is that the configuration decision-making process is regarded as the game for different disciplines and technologies, and the aircraft components are players. The payoff function with highest total gain means that ac- cording to the game protocols and multidimensional theory, the optimal aircraft configuration within the strategy set will be cho- sen. The decision-making model is applied to conceptual design process of the high altitude long endurance (HALE) unmanned aerial vehicle (UAV) based on the assessment of technological risk. The obtained optimum configuration is quite consistent with the current HALE UAV development trends. Thus, taking into account the coupling and interference factors, the multidimensional gaming model based on aircraft components will be an effective analysis method in the decision-making process of aircraft optimum configuration. 展开更多
关键词 decision making optimum configuration components interference multidimensional game theory disciplines coupling technological risk
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The Ways to Improve the Efficiency of Maize Breeding 被引量:1
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作者 张旭 刘晓萍 +4 位作者 郝学景 李立公 魏春 何光荣 马永良 《Agricultural Science & Technology》 CAS 2010年第9期175-179,共5页
Referring to corn breeding literature at home and abroad,the possible ways to improve the efficiency of maize breeding were discussed.The results showed that through the summary and reflection on breeding objectives a... Referring to corn breeding literature at home and abroad,the possible ways to improve the efficiency of maize breeding were discussed.The results showed that through the summary and reflection on breeding objectives and strategies,and improvement and optimization of breeding techniques and methods,as well as adjustment and simplification of experimental design and implementation,the breeding cost would be greatly reduced,and the breeding efficiency would be improved. 展开更多
关键词 MAIZE Breeding method Improving ways
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Analysis and Optimum Design of Differential Inductors Using Distributed Capacitance Model 被引量:1
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作者 菅洪彦 唐长文 +1 位作者 何捷 闵昊 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2005年第6期1077-1082,共6页
A distributed capacitance model for monolithic inductors is developed to predict the equivalently parasitical capacitances of the inductor.The ratio of the self-resonant frequency (f SR) of the differential-driven sym... A distributed capacitance model for monolithic inductors is developed to predict the equivalently parasitical capacitances of the inductor.The ratio of the self-resonant frequency (f SR) of the differential-driven symmetric inductor to the f SR of the single-ended driven inductor is firstly predicted and explained.Compared with a single-ended configuration,experimental data demonstrate that the differential inductor offers a 127% greater maximum quality factor and a broader range of operating frequencies.Two differential inductors with low parasitical capacitance are developed and validated. 展开更多
关键词 distributed capacitance model self-resonant frequency ratio quality factor differential inductor optimum design
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OPTIMUM OF PRESSURE RATIOS OF MULTI-STAGE RECIPROCATING COMPRESSOR WITH PRACTICAL INTER-COOLING 被引量:1
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作者 刘卫华 昂海松 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2002年第2期177-181,共5页
The optimum pressure ratio distribution of a multistage reciprocating compressor is presented based on the assumption, i.e. the inter stage cooling is perfect and there are no pressure losses. The optimization of the... The optimum pressure ratio distribution of a multistage reciprocating compressor is presented based on the assumption, i.e. the inter stage cooling is perfect and there are no pressure losses. The optimization of the two or three stage pressure ratio is analyzed in two cases of constant heat transfer rate for the inter cooler or constant inter stage inlet temperature, based on the minimum of the sum of theoretical compression power at each stage about a multi stage reciprocating compressor. Furthermore, with an example of two stage compressor the influence on the sum of the power of each stage is analyzed when practical pressure ratio deviates from the optimum value. It is obtained that under different cooling conditions the optimum pressure ratio distribution of the multi stage compression is various, and the change of the optimum pressure ratio within a small range has little influence on the sum of the power each stage. For the two stage compression, this range can be represented as ε 1=(0 96~1 06)ε 1j . 展开更多
关键词 inter cooler multi stage compressor pressure ratio optimum
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Study on Optimum Fertilization Model of Potato Intercropped with Sugarcane
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作者 江泽普 廖青 +5 位作者 谭裕模 韦广泼 邢颖 汪羽宁 刘斌 梁潘霞 《Agricultural Science & Technology》 CAS 2013年第1期138-143,共6页
[Objective] The paper was to study the effects of different ratios of N, P and K on yield of potato intercropped with sugarcane in Lateritic red earth area of Guangxi, and seek the best N, P and K ratio for nutrition ... [Objective] The paper was to study the effects of different ratios of N, P and K on yield of potato intercropped with sugarcane in Lateritic red earth area of Guangxi, and seek the best N, P and K ratio for nutrition model of potato inter- cropped with sugarcane. [Method]Two field experiments adopted the optimum com- pound design (311-A) were conducted in Long'an County of Guangxi Province in 2011 and 2012, respectively. The polynomial regression models of fertilizer applica- tion and quadratic of three factors were established by SAS statistical analysis soft- ware, and optimum nutrient simulation models of potato were obtained by computer processing. [Result] The combined application of low nitrogen and mid-high potassi- um and phosphorus fertilizer contributed to higher potato yield in experimental condi- tion. The regression model of potato yield (Yll and Y12) and dosage of N(X1), P (X2), K(X3) were established by using SAS statistical analysis software, in 2011 and 2012, respectively. They were Y11 =14 725.28 -415.39X1 +741.99X2 +607.83)(3-447.92X1X2- 144.09X1X3 -405.83X2X3 -267.82X1^2-795.67X2^2 -642.10X3^2, R =0.927 2; and Y12 =14 342.60 -896.25X1 +548.62X2 +925.51 X3 +67.81 X1X2 +531.60X1X3 -99.00X2X3 -904.00X1^2 - 1121.36X2^2-596.64X3^2,R=0.926 6. The regression mathematics model of potato yields preferably fit with actual situation in the locality, and have higher practical value, so it could be used for fertilizer decision and forecast. Using the computer to carry on the optimization, the N, P and K dosage of the best potato yield intercropped with sugarcane was obtained. The dosage of N, P2O5, K2O were 108.8-140.6, 172.5-204.4 and 285.9 kg/hm2, respectively. [Conclusion] The best N, P and K ratio of potato yield intercropped with sugarcane was 1:(1.23-1.68):(2.03-2.63). 展开更多
关键词 INTERCROPPING optimum fertilization model Sugarcane-Potato
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X-Ways Forensics在电子数据司法鉴定中的应用 被引量:1
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作者 尹丹 《中国司法鉴定》 北大核心 2009年第5期73-75,共3页
通过介绍几种常用的电子数据司法鉴定工具的发展概况和特点,并对X-Ways Forensics的磁盘快照等功能,在电子数据司法鉴定工作中的应用进行了阐述。
关键词 电子证据 X—ways 磁盘快照
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Is There an Optimum Age For Foreign Language Learning?
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作者 兰军 《陕西师范大学学报(哲学社会科学版)》 CSSCI 北大核心 2001年第S2期334-336,共3页
Age is one of the factors which influnce foreign language learning, but not the most important one. Comparision on the effect of foreign language learning between adults and children cannot rely merely on age. So the ... Age is one of the factors which influnce foreign language learning, but not the most important one. Comparision on the effect of foreign language learning between adults and children cannot rely merely on age. So the question of an optimum age for foreign language learning is not a simple one which is only related to age. There are different optimum ages for different aims and demands of learning foreign language. 展开更多
关键词 optimum age FOREIGN LANGUAGE LEARNING ADULT CHILDREN
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OPTIMUM CUTTING ANALYSIS METHOD OF MEMBRANE STRUCTURE
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作者 邵小方 吴健生 《Transactions of Tianjin University》 EI CAS 1995年第2期189+186-187,189,共4页
By the optimum theory, a new cutting analytical method of the membrane structure is developed. The B-spline curve is applied to make smooth the boundary of the membrane strip. By this method, the cutting accuracy is i... By the optimum theory, a new cutting analytical method of the membrane structure is developed. The B-spline curve is applied to make smooth the boundary of the membrane strip. By this method, the cutting accuracy is improved. Finally, a cutting analysis example of a tension membrane structure is given. 展开更多
关键词 membrane structure cutting analysis optimum theory
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Optimum Design of Impedance Simulator for Phased Array Antnnas
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作者 吕昕 李世智 《Journal of Beijing Institute of Technology》 EI CAS 1994年第1期63+59-63,共6页
The impedance of a solid state active phased array antenna varing with frequency and beam scanning scanning angle be matched with the solid state active matching network (SSAMN). In order to adjust and measure the rad... The impedance of a solid state active phased array antenna varing with frequency and beam scanning scanning angle be matched with the solid state active matching network (SSAMN). In order to adjust and measure the radar conveniently and Securely, it is necessary for the impedance of the simulator of the phased array antennas to be optimized.Having selected the PIN dilde controlling circuits and the circuit parameters optimized,the simulator circuit is determined through numerical computation The experiment is given in support of the simulation. 展开更多
关键词 phase array antennas impedance inatching simulation optimum design active circuits
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DYNAMICAL OPTIMUM DESIGN OF THE MECHANICAL OSCILLATION SYSTEM IN FLUIDIC GENERATOR
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作者 李福松 陈建军 《兵工学报》 EI CAS CSCD 北大核心 2000年第1期-,共4页
文中通过对射流发电机工作原理、结构特点及作用荷载的分析,建立了射流发电机机械振动系统的动力优化设计数学模型,以结构尺寸为设计变量,使结构重量极小化,满足动力位移、应力响应、基频以及尺寸限等约束条件,利用振型迭加法和复... 文中通过对射流发电机工作原理、结构特点及作用荷载的分析,建立了射流发电机机械振动系统的动力优化设计数学模型,以结构尺寸为设计变量,使结构重量极小化,满足动力位移、应力响应、基频以及尺寸限等约束条件,利用振型迭加法和复合形法求解。优化和试验结果表明:经优化后,既减轻结构重量,又显著地提高了射流发电机的输出功率。 展开更多
关键词 引信 射流技术 电源 有限元法 动力响应 动力优化 DYNAMICAL optimum DESIGN OF THE MECHANICAL
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直动从动杆圆锥凸轮机构的最佳推程、回程运动角Optimum{Φ_0,Φ′_0}及其求解方法 被引量:1
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作者 常勇 王知行 《机械设计》 CSCD 北大核心 2002年第5期24-26,共3页
在推程、回程运动角之和Φ0 +Φ′0 =C(定值 )的情况下 ,必存在某一对推程、回程运动角的最佳分配Optimum {Φ0 ,Φ′0 };当选用该最佳分配时 ,直动从动杆圆锥凸轮基圆半径r0 取得其最小值r0min。在发现、揭示出上述事实的基础上 ,研究... 在推程、回程运动角之和Φ0 +Φ′0 =C(定值 )的情况下 ,必存在某一对推程、回程运动角的最佳分配Optimum {Φ0 ,Φ′0 };当选用该最佳分配时 ,直动从动杆圆锥凸轮基圆半径r0 取得其最小值r0min。在发现、揭示出上述事实的基础上 ,研究解决了当选取最佳分配Optimum{Φ0 ,Φ′0 }时 ,按许用压力角条件求解直动从动杆圆锥凸轮基圆半径最小值r0min 的解析方法。 展开更多
关键词 直动从动杆 圆锥凸轮机构 基圆半径 推程运动角 回程运动角
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Effective Ways to Improve Students'Interests in English Classes
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作者 彭茜茜 《海外英语》 2013年第10X期70-71,74,共3页
Interest is the key role in English learning. Thus, English teachers should take effective ways to raise students'interests in teaching classes. Scientific investigation has proved that using effective approaches ... Interest is the key role in English learning. Thus, English teachers should take effective ways to raise students'interests in teaching classes. Scientific investigation has proved that using effective approaches certainly helps arousing students'interests in English teaching. 展开更多
关键词 ENGLISH learning INTEREST TEACHING ways ENGLISH cl
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Ways to Improve Students’Speaking Ability in English for Careers
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作者 李晓莉 《海外英语》 2020年第20期268-269,共2页
English for Careers is a public course for non-English majors,whose objectives are to develop students’basic language skills for work-related activities:listening,reading,speaking,and writing.As far as the four skill... English for Careers is a public course for non-English majors,whose objectives are to develop students’basic language skills for work-related activities:listening,reading,speaking,and writing.As far as the four skills are concerned,most students in higher vocational colleges have the very poor speaking ability.How to improve students’speaking ability is a hard and urgent task for English teachers.This article sets out to analyze the reasons for this problem in English for Careers.Then,based on the second language acquisition and current teaching theory,ways of improving students’speaking ability are suggested. 展开更多
关键词 English for Careers speaking ability ways
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Atlas Based Kinematic Optimum Design of the Stewart Parallel Manipulator 被引量:6
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作者 SHAO Zhufeng TANG Xiaoqiang +1 位作者 WANG Liping SUN Dengfeng 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2015年第1期20-28,共9页
Optimum design is a key approach to make full use of potential advantages of a parallel manipulator. The optimum design of multi-parameter parallel manipulators(more than three design parameters), such as Stewart ma... Optimum design is a key approach to make full use of potential advantages of a parallel manipulator. The optimum design of multi-parameter parallel manipulators(more than three design parameters), such as Stewart manipulator, relies on analysis based and algorithm based optimum design methods, which fall to be accurate or intuitive. To solve this problem and achieve both accurate and intuition, atlas based optimum design of a general Stewart parallel manipulator is established, with rational selection of design parameters. Based on the defined spherical usable workspace(SUW), primary kinematic performance indices of the Stewart manipulator involving workspace and condition number are introduced and analyzed. Then, corresponding performance atlases are drawn with the established non-dimensional design space, and impact of joint distribution angles on the manipulator performance is analyzed and illustrated. At last, an example on atlas based optimum design of the Stewart manipulator is accomplished to illustrate the optimum design process, considering the end-effector posture. Deduced atlases can be flexibly applied to both quantitative and qualitative analysis to get the desired optimal design for the Stewart manipulator with respect to related performance requirements. Besides, the established optimum design method can be further applied to other multi-parameter parallel manipulators. 展开更多
关键词 optimum design performance atlas parallel mechanism STEWART
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Fuzzy Optimum Model of Semi-Structural Decision for Lectotype Optimization of Offshore Platforms 被引量:10
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作者 陈守煜 伏广涛 +1 位作者 王建明 刘刚 《China Ocean Engineering》 SCIE EI 2001年第4期453-466,共14页
In the process of concept design of offshore platforms, it is necessary to select the best from feasible alternatives through comparison and filter. The criterion set, used to evaluate and select the satisfying altern... In the process of concept design of offshore platforms, it is necessary to select the best from feasible alternatives through comparison and filter. The criterion set, used to evaluate and select the satisfying alternative, consists of many qualitative and quantitative factors. Therefore, the selection is a problem of multicriteria and semi-structural decision-making. Different from traditional methods in semi-structural decision-making, a new framework and methodology is presented in this paper for evaluation of offshore platform alternatives, First, the criterion set is established for the evaluation of alternatives. Next, the approach is studied to construct the relative membership degree matrix, in which both qualitative and quantitative factors are consistent with the uniform calculating standard. And then a new weight-assessing method is developed for calculation of the weights based on the relative membership degree matrix. Finally, a multi-hierarchy fuzzy optimum model is adopted to select the satisfying offshore platform alternative. A case study shows that the new framework and methodology are scientific, reasonable and easy to use in practice. 展开更多
关键词 offshore platform lectotype optimization semi-structure relative membership degree matrix weightvector fuzzy optimum
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Optimum Weight Design of Functionally Graded Material Gears 被引量:8
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作者 JING Shikai ZHANG He +1 位作者 ZHOU Jingtao SONG Guohua 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2015年第6期1186-1193,共8页
Traditional gear weight optimization methods consider gear tooth number, module, face width or other dimension parameters of gear as design variables. However, due to the complicated form and geometric features peculi... Traditional gear weight optimization methods consider gear tooth number, module, face width or other dimension parameters of gear as design variables. However, due to the complicated form and geometric features peculiar to the gear, there will be large amounts of design parameters in gear design, and the influences of gear parameters changing on gear trains, transmission system and the whole equipment have to be taken into account, which increases the complexity of optimization problem. This paper puts forward to apply functionally graded materials(FGMs) to gears and then conduct the optimization. According to the force situation of gears, the material distribution form of FGM gears is determined. Then based on the performance parameters analysis of FGMs and the practical working demands for gears, a multi-objective optimization model is formed. Finally by using the goal driven optimization(GDO) method, the optimal material distribution is achieved, which makes gear weight and the maximum deformation be minimum and the maximum bending stress do not exceed the allowable stress. As an example, the applying of FGM to automotive transmission gear is conducted to illustrate the optimization design process and the result shows that under the condition of keeping the normal working performance of gear, the method achieves in greatly reducing the gear weight. This research proposes a FGM gears design method that is able to largely reduce the weight of gears by optimizing the microscopic material parameters instead of changing the macroscopic dimension parameters of gears, which reduces the complexity of gear weight optimization problem. 展开更多
关键词 GEARS optimum weight design functionally graded materials material distribution additive manufacturing
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Limit equilibrium analysis for stability of soil nailed slope and optimum design of soil nailing parameters 被引量:5
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作者 DENG Dong-ping LI Liang ZHAO Lian-heng 《Journal of Central South University》 SCIE EI CAS CSCD 2017年第11期2496-2503,共8页
Reinforcement of slopes using soil nailing can effectively improve slope stability, and it has been widely used in upgrading cut slopes. Based on the assumptions of stresses on the slip surface, a new method for analy... Reinforcement of slopes using soil nailing can effectively improve slope stability, and it has been widely used in upgrading cut slopes. Based on the assumptions of stresses on the slip surface, a new method for analyzing the stability of a slope reinforced with soil nails was established in the limit equilibrium theory framework, by considering that slope sliding occurs owing to shear failure of the slip surface, which subjects to Mohr–Coulomb(M–C) strength criterion. Meanwhile, in order to easily analyze the stability of a soil nailed slope in actual engineering and facilitate optimum design of parameters for soil nailing, factor of safety(FOS) contour curve charts were drawn on the basis of the established linear proportional relationship between the spacing of soil nails and slope height, and the length of soil nails and slope height. Then, by analyzing and verifying the results obtained from classic examples, some conclusions can be got as follows: 1) The results obtained from the current method are close to those obtained from the traditional limit equilibrium methods, and the current method can provide a strict solution for the slope FOS as it satisfies all the static equilibrium conditions of a sliding body, thus confirming the feasibility of the current method; 2) The slope FOS contour curve charts can be used not only to reliably analyze the stability of a soil nailed slope, but also to design optimally the parameters of soil nailing for the slope with a certain safety requirement. 展开更多
关键词 SLOPE STABILITY soil NAILING LIMIT EQUILIBRIUM factor of safety CONTOUR curve optimum design
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Optimum design and layout of the cooling apparatus for long compaignship blast furnace 被引量:10
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作者 ShusenCheng TianjunYang +3 位作者 QingguoXue HaibinZuo XiaowuGao WeiguoYang 《Journal of University of Science and Technology Beijing》 CSCD 2003年第4期24-28,共5页
Generally, the cooler life can determine the blast furnace life. Theslag-metal skull frozen on the cooler can separate the cooler from the hot gas flow in blastfurnace. The key problem is how to freeze liquid slag-met... Generally, the cooler life can determine the blast furnace life. Theslag-metal skull frozen on the cooler can separate the cooler from the hot gas flow in blastfurnace. The key problem is how to freeze liquid slag-metal on the cooler, and the main measure isto decrease the hot surface temperature of the cooler. The computational technology of heat transferwas practically used for long campaign blast furnace design. The optimum design of the cast ironstave, copper stave, plate-stave combined system and flange stave was given by the computingresults. According to the results, the optimum arrangement of different coolers (cast iron or copperstave, flange stave and plate-stave combined system) on different height of blast furnace wall canbe found through all these temperature fields. 展开更多
关键词 blast furnace COOLER optimum layout COMPUTATIONAL
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