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STUDY ON SUB-DRY CUTTING GCr12

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Chinese Journal of Mechanical engineering 2002年第1期15卷 40-42页

作者： Ren Jialong Department of Mechanical engineering，East china shipbuilding {3.， Zhengjiang 212003.china Department of Mechanical engineering East China Shipbuilding Institute Zhengjiang 212003 China

through the comparison study on cutting force, cutting temperature andmachined surface quality with the sub-dry cutting traditional cooling method, it is shown thatsub-dry cutting can retard the wear of the tooled par... 详细信息

关键词： Sub-dry cutting Production without pollution Bearing steal

Revision of seismic design codes corresponding to building damagesin the “5.12” Wenchuan earthquake

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Earthquake engineering and engineering Vibration 2010年第2期9卷 147-155页

作者： Wang Yayong institute of Earthquake engineering,{3. Academy of Building {3., Beijing 100013.{3. institute of Earthquake engineering China Academy of Building Research Beijing 100013 China

A large number of buildings were seriously damaged or collapsed in the "5.12" Wenchuan earthquake. Based on field surveys and studies of damage to different types of buildings, seismic design codes have been updated. this paper briefly summarizes some of the major revisions that have been incorporated into the "Standard for classification of seismic protection of building constructions GB50223.2008" and "Code for Seismic Design of Buildings GB50011-2001." the definition of seismic fortification class for buildings has been revisited, and as a result, the seismic classifications for schools, hospitals and other buildings that hold large populations such as evacuation shelters and information centers have been upgraded in the GB50223.2008 Code. the main aspects of the revised GB50011-2001 code include: (a) modification of the seismic intensity specified for the Provinces of Sichuan, Shanxi and Gansu; (b) basic conceptual design for retaining walls and building foundations in mountainous areas; (c) regularity of building configuration; (d) integration of masonry structures and precast RC floors; (e) requirements for calculating and detailing stair shafts; and (f) limiting the use of single-bay RC frame structures. Some significant examples of damage in the epicenter areas are provided as a reference in the discussion on the consequences of collapse, the importance of duplicate structural systems, and the integration of RC and masonry structures.

关键词： Wenchuan earthquake earthquake damage to buildings revision of seismic design codes

the characteristics of arc beam shaping in hybrid plasma and laser deposition manufacturing

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Science china(Technological Sciences) 2006年第2期49卷 238-247页

作者： ZHANG Hai’ou1, QIAN Yingping1,3. WANG Guilan1 & ZHENG Qiguang2 1. School of Material Science and Technology, Huazhong University of Science and Technology, Wuhan 43.074, china 2. institute of Laser Technology and engineering, Huazhong University of Science and Technology, Wuhan 43.074, china 3. Mechanical engineering College, hubei University of Technology, Wuhan 43.068, china 1. School of Material Science and Technology Huazhong University of Science and Technology Wuhan 430074 China 3. Mechanical engineering College Hubei University of Technology Wuhan 430068 China 2. institute of Laser Technology and engineering Huazhong University of Science and Technology Wuhan 430074 China

As a new direct metal prototyping technology,the hybrid plasma and laser deposition manufacturing (PLDM) is proposed in this paper. In order to figure out the characteristics of plasma arc beam and mould in the PLDM process of high temperature alloy, the high speed CCD camera is used to obtain the picture around the plasma arc. Afterwards the sketch of picture is clearly obtained. And the effect of laser parameter, such as average power, pulse width, pulse repetition frequency and the angle between laser beam and plasma arc beam on the plasma arc appearance, is studied experimentally. the results show that the modality of plasma arc beam is markedly influenced by laser beam. And the improvements of shape precision and surface state of the layer deposited by PLDM are confirmed.

关键词： plasma hybrid laser, direct deposition, plasma arc beam, molding character, high-temperature alloy.

Analysis　of　Entropy　Generation　of　Combined　Heat　and　Mass　Transfer　in　Internal　and　External　Flows　with　the　Assumption　of　Local　thermodynamic　Equilibrium

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Journal of thermal Science 1994年第1期3卷 1-6页

作者： Shouguang Yao(Department of Power engineering, East china shipbuilding {3., Jiangsu Zhenjiang, 212003.china) 1. Department of Power engineering East China Shipbuilding Institute 212003 Jiangsu Zhenjiang China

In this paper, the control volume method is used to establish the general expression of entropy generation due to combined convective heat and mass transfer in internal and external fluid streams. theexpression accounts for irreversibilities due to the presence of heat transfer across a finite temperaturedifference, mass transfer across a finite difference in the chemical potential of a species, and due toflow friction. Based on the assumption of local thermodynamic equilibrium, the generalized form ofthe Gibbs equation is used in this analysis. the results are applied to two fundamental problems offorced convection heat and mass transfer in internal and external flows. After minimizing the entropygeneration, useful conclusions are derived that are typical of the second law viewpoint for the definitionof the optimum operation conditions for the specified applications, which is a' valuable criterion foroptimum design of heat and fluid flow devices.

关键词： entropy generation local thermodynamic equilibrium heat and mass transfer

A preliminary study on seismic design criteria of offshore platforms in Bohai Sea of china

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Earthquake engineering and engineering Vibration 2010年第2期9卷 223-231页

作者： Peng Yanju1,Lu Yuejun1,Yan Jiaquan2,Tang Rongyu1,Wang Junqin3.and Li Jiagang3.1. institute of Crustal Dynamics,china Earthquake Administration,Beijing 100085,china 2. institute of Geophysics,china Earthquake Administration,Beijing 100081,china 3. Beijing research Center of china National Offshore Oil Corp.,Beijing 100027,china institute of Crustal Dynamics China Earthquake Administration Beijing 100085 China

this paper analyzes the seismicity in Bohai Sea,introducing a shape factor K to characterize the seismic risk distribution in sub-regions of the sea. Based on the seismic design ground motions for 46 platforms located in the Bohai Sea,a statistical analysis was performed for different peak ground acceleration (PGA) ratios at two different probability levels. In accordance with the two-stage design method,a scheme of two seismic design levels is proposed,and two seismic design objectives are established respectively for the strength level earthquake and the ductility level earthquake. By analogy with and comparison to the Chinese seismic design code for buildings,it is proposed that the probability level for the strength level earthquake and ductility level earthquake have a return period of 200 and 1000 - 2500 years,respectively. the validity of these proposed values is discussed. Finally,the PGAs corresponding to these two probability levels are calculated for different sub-regions of the Bohai Sea.

关键词： fixed offshore platform seismic design level seismic design objective return period Bohai Sea

Allocation of power generating and shipping of Hanjiang upstream cascade

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Progress in Natural Science:Materials International 2005年第8期15卷 733-741页

作者： LIU Junping1* and CHANG Mingqi 2,3.1. School of Civil engineering and Architecture, Zhejiang University of Technology, Hangzhou 3.0014, china 2. institute of Water Resources & Hydroelectric engineering, Xi'an University of Technology, Xi'an 710048, china 3. Shanxi institute of Water Resources, Taiyuan 03.001, china) School of Civil engineering and Architecture Zhejiang University of Technology Hangzhou 310014 China institute of Water Resources and Hydroelectric engineering Xi'an University of Technology Xi'an 710048 China Shanxi institute of Water Resources Taiyuan 030001 China

the optimal model and simulating model of the Hanjiang cascade reservoirs operation with one day as its calculating period are established to coordinate the contradictions between power generating and shipping. the optimal model is solved by progressive optimality algorithm method adopting the theory of large system decomposing and coordinating. By analyzing the water allocation results obtained from six schemes, which are two cascades, four cascades and seven cascades joint operation considering shipping or not, the contradiction degree between power generating and shipping is investigated and some joint operation schemes are proposed.

关键词： cascade power generating contradiction shipping optimal operation.

RAZUMIKHIN-TYPE thEOREMS FOR ASYMPTOTIC STABILITY OF IMPULSIVE STOCHASTIC FUNCTIONAL DIFFERENTIAL SYSTEMS

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Journal of Systems Science and Systems engineering 2010年第1期19卷 72-84页

作者： Pei CHENG~1 Feiqi DENG~2 Xisheng DAI~3.Systems engineering institute,South{3. University of Technology,Guangzhou 510640,{3. Systems engineering institute South China University of Technology Guangzhou China

In this paper, we investigate the pth moment uniformly asymptotic stability of impulsive stochastic ftmctional differential systems by extending some Razumikhin-type theorems. Based on the Lyapunov functions and Razumikhin techniques, some criteria are established and their applications to impulsive stochastic delay systems are proposed. An illustrative example shows the effectiveness of our results.

关键词： Stochastic functional differential systems Impulse Razumiltial theorems Asymptotic stability

A land surface model incorporated with soil freeze/thaw and its application in GAME/Tibet

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Science china Earth Sciences 2006年第12期49卷 1311-1322页

作者： HU Heping1, YE Baisheng2, ZHOU Yuhua3.& TIAN Fuqiang1 1. Department of Hydraulic engineering, Tsinghua University, Beijing 100084, china 2. Cold and Arid Regions Environmental and engineering {3. institute, Chinese Academy of Sciences, Lanzhou 73.000, china 3. Department of Civil engineering, Massachusetts institute of Technology, USA 1. Department of Hydraulic engineering Tsinghua University Beijing 100084 China 2. Cold and Arid Regions Environmental and engineering research institute Chinese Academy of Sciences Lanzhou 730000 China 3. Department of Civil engineering Massachusetts Institute of Technology USA

Land surface process is of great importance in global climate change, moisture and heat exchange in the interface of the earth and atmosphere, human impacts on the environment and eco- system, etc. Soil freeze/thaw plays an important role in cold land surface processes. In this work the diurnal freeze/thaw effects on energy partition in the context of GAME/Tibet are studied. A sophisti- cated land surface model is developed, the particular aspect of which is its physical consideration of soil freeze/thaw and vapor flux. the simultaneous water and heat transfer soil sub-model not only reflects the water flow from unfrozen zone to frozen fringe in freezing/thawing soil, but also demon- strates the change of moisture and temperature field induced by vapor flux from high temperature zone to low temperature zone, which makes the model applicable for various circumstances. the modified Picard numerical method is employed to help with the water balance and convergence of the numerical scheme. Finally, the model is applied to analyze the diurnal energy and water cycle char- acteristics over the Tibetan Plateau using the Game/Tibet datasets observed in May and July of 1998. Heat and energy transfer simulation shows that: (i) there exists a negative feedback mechanism between soil freeze/thaw and soil temperature/ground heat flux; (ii) during freezing period all three heat fluxes do not vary apparently, in spite of the fact that the negative soil temperature is higher than that not considering soil freeze; (iii) during thawing period, ground heat flux increases, and sensible heat flux decreases, but latent heat flux does not change much; and (iv) during freezing period, soil temperature decreases, though ground heat flux increases.

关键词： land surface model,soil freeze/thaw,GAME/Tibet,simultaneous liquid,vapor and heat transfer.

Impacts of permafrost changes on alpine ecosystem in Qinghai-Tibet Plateau

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Science china Earth Sciences 2006年第11期49卷 1156-1169页

作者： WANG Genxu1,3., LI Yuanshou2 , WU Qingbai2 & WANG Yibo3.1. institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, china 2. Cold and Arid Regions Environmental and engineering {3. institute, Chinese Academy of Sciences, Lanzhou 73.000, china 3. Resource and Environment School, Lanzhou University, Lanzhou 73.000, china 1. institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu 610041 China 3. Resource and Environment School Lanzhou University Lanzhou 730000 China 2. Cold and Arid Regions Environmental and engineering research institute Chinese Academy of Sciences Lanzhou 730000 China

Alpine cold ecosystem with permafrost environment is quite sensitive to climatic changes and the changes in permafrost can significantly affect the alpine ecosystem. the vegetation coverage, grassland biomass and soil nutrient and texture are selected to indicate the regime of alpine cold ecosystems in the Qinghai-Tibet Plateau. the interactions between alpine ecosystem and permafrost were investigated with the depth of active layer, permafrost thickness and mean annual ground temperature (MAGTs). Based on the statistics model of GPTR for MAGTs and annual air temperatures, an analysis method was developed to analyze the impacts of permafrost changes on the alpine ecosystems. Under the climate change and human engineering activities, the permafrost change and its impacts on alpine ecosystems in the permafrost region between the Kunlun Mountains and the Tanggula Range of Qinghai-Tibet Plateau are studied in this paper. the results showed that the per- mafrost changes have a different influence on different alpine ecosystems. With the increase in the thickness of active layer, the vegetation cover and biomass of the alpine cold meadow exhibit a significant conic reduction, the soil organic matter content of the alpine cold meadow ecosystem shows an exponential decrease, and the surface soil materials become coarse and gravelly. the alpine cold steppe ecosystem, however, seems to have a relatively weak relation to the permafrost environment. those relationships resulted in the fact that the distribution area of alpine cold meadow decreased by 7.98% and alpine cold swamp decreased by 28.11% under the permafrost environment degradation during recent 15 years. In the future 50 years the alpine cold meadow ecosystems in different geomorphologic units may have different responses to the changes of the permafrost under different climate warming conditions, among them the alpine cold meadow and swamp ecosystem located in the low mountain and plateau area will have a relatively

关键词： permafrost environment, alpine cold ecosystem, statistics relationship, climate change, impacts, Qinghai-Tibet Plateau.