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从莫言获奖谈英文文学期刊的困境与出路--以《中国文学》和《人民文学》英文版为例 被引量:5
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作者 肖娴 《出版发行研究》 CSSCI 北大核心 2012年第11期8-11,共4页
本文从创刊背景、刊物特点、翻译选材、翻译人才与译文质量及海外发行等方面比较了《中国文学》与《人民文学》英文版,分析探讨建国以来英文文学期刊的出版及对外传播的困境与出路。
关键词 英文文学期刊 《中国文学 《人民文学英文
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Multi-scaled simulation of latticed frames considering bending collapse of pipes 被引量:7
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作者 刘海锋 LOU Rong +1 位作者 LUO Yao-zhi DANG Hui-xue 《Journal of Chongqing University》 CAS 2012年第4期167-176,共10页
To consider the bending collapse of the pipes in the latticed frames, based on the multi-scale simulation, the collapsed parts of the pipe are meshed by the shell elements as micro-scaled models, and the other parts a... To consider the bending collapse of the pipes in the latticed frames, based on the multi-scale simulation, the collapsed parts of the pipe are meshed by the shell elements as micro-scaled models, and the other parts are meshed by beam elements macro-models. The incremental displacement constraint equations for the nodes on the section between the two models are established based on the plane section premise of classical beam theory. The method to introduce the constraint equations is derived based on the Updated Largrangian method. The location of the micro-model is predicted by the stress field of the beam element, and the length of the collapsed part is adjusted by the plastic energy in the micro model. Several examples are included to illustrate the efficiency and accuracy of this method. 展开更多
关键词 multi-scaled simulation latticed frames bending collapse plane section premise
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Psychosocial oncology in China——Challenges and opportunities 被引量:2
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作者 Lili Tang Janet de Groot Barry D. Bultz 《The Chinese-German Journal of Clinical Oncology》 CAS 2009年第3期123-128,共6页
Objective:In China over the past decade,psychosocial oncology has emerged as a new program. Development of this program requires attention to current opportunities,obstacles and cultural concerns. Methods: A selected ... Objective:In China over the past decade,psychosocial oncology has emerged as a new program. Development of this program requires attention to current opportunities,obstacles and cultural concerns. Methods: A selected literature review of academic papers in Chinese and English language journals and web sites was analyzed for themes regarding the current status,challenges,and opportunities for psychosocial oncology in China. Results: China’s national cancer strategy (2004-2010),based on WHO guidelines,is focused on cancer prevention and treatment,as well as quality of life among cancer patients and their families. The Chinese Anti-Cancer Association is now funding research,training and international collaboration in psychosocial oncology. The newly organized Chinese Psychosocial Oncology Society,founded in 2006,aims to provide a national forum for psychosocial oncology research. Cultural and systemic challenges to establishing psychosocial oncology as a core discipline in China include: (1) the family’s desire to ‘protect’ cancer patients by with-holding cancer-related information; (2) stigma and privacy regarding mental health issues; (3) biomedical practitioners’ claims that psychosocial on-cology is not sufficiently evidence-based; and (4) limited funding for psychosocial oncology care and research. Conclusion: The International Psycho-Oncology Society (IPOS) is considered a valuable resource towards China’s interest in partnering with the international psychosocial oncology community to enhance the discipline globally. 展开更多
关键词 psychosocial oncology China
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Seismic performance testing of reinforcement concrete frames strengthened with Y-eccentrically brace
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作者 王大鹏 YU An-lin XUE Li-ming 《Journal of Chongqing University》 CAS 2012年第4期151-160,共10页
Two single-storey single-span reinforcement concrete (RC) frame structures strengthened with Y-eccentrically brace were designed and manufactured to be 1/3 scale. The pseudo-dynamic testing method was used to study ... Two single-storey single-span reinforcement concrete (RC) frame structures strengthened with Y-eccentrically brace were designed and manufactured to be 1/3 scale. The pseudo-dynamic testing method was used to study the mechanical characteristics and the seismic performance under E1-Centro earthquake action with different peak acceleration adjusted by China's Code for Seismic Design of Buildings. The test results indicate that RC frame structures strengthened with Y- eccentrically steel brace present perfect seismic performance under strong earthquake action owing to the good ductility, strong bearing capability and fine energy absorbing capability provided by energy dissipation element and high lateral stiffness provided by diagonal braces. The seismic performance is also affected by the length of outsourcing steel at the joint between energy dissipation element of eccentric steel brace and RC frame beam. The joint should be considerably designed to make sure that shear failure can firstly occur in energy dissipation element. 展开更多
关键词 Y-eccentrically steel brace energy dissipation element pseudo-dynamic test seismic performance shear failure
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On construction waste disposal in Chongqing
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作者 廖奇云 ZHONG Guo-yi +1 位作者 TAO Yan-yu JIA Shun 《Journal of Chongqing University》 CAS 2012年第4期195-202,共8页
With rapid development of the construction industry in China, lots of construction materials are being widely reused. Meanwhile, more and more materials for building remover or demolition enter into the environment as... With rapid development of the construction industry in China, lots of construction materials are being widely reused. Meanwhile, more and more materials for building remover or demolition enter into the environment as a result. However, China is facing big building garbage pollution, with simple disposal methods and low efficiency, which urgently needs to be improved. The paper takes Chongqing as an example to illustrate existing problems in this field and then puts forward corresponding countermeasures from the aspects of economy, technology, management and policy, aiming at enhancing the level of construction waste disposal in China. 展开更多
关键词 construction waste COUNTERMEASURE CHONGQING DISPOSAL
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Reducing sugars production from pretreated rapeseed straw
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作者 肖弥彰 SHIN Hyun-jae DONG Qiu-hua 《Journal of Chongqing University》 CAS 2012年第4期183-194,共12页
Lignocellulosic biomass, being treated only with ammonia, treated with ammonia and then autoclaved, and treated with white-rot fungi after being mechanically chipped, were carried out to access the effects of lignocel... Lignocellulosic biomass, being treated only with ammonia, treated with ammonia and then autoclaved, and treated with white-rot fungi after being mechanically chipped, were carried out to access the effects of lignocellulose degradation by white-rot fimgi cultured on rapeseed straw. Fourier transform infrared spectroscopic analysis was used to show that the white-rot fungus Bjerkandera sp. strain increase the susceptibility of straw to enzymatic saccharification by modifying the lignin component, revealing the effect of these pretreatments on enzymatic saccharification. Reducing sugar production from straws pretreated by ammonia/mechanical chipping/fungi degradation was 29.80% higher than the samples treated with ammonia/autoclaving, indicating an effective degradation of phenolic compounds. After ammonia pretreatment 41% of the straw was converted to RS (reducing sugars) (glucose 50%). After 5 weeks pretreatment with the white-rot fungus, 54.8% of rapeseed straw was further converted to RS, 74% of which was glucose; while only 12% of the control straw was converted (glucose 42%). The white-rot fungus Bjerkandera sp. strain degraded rapeseed straw preferentially at the early stage (before 20 d), and the degradation selectivity was 0.181 1 (cellulose), 0.364 1 (hemicellulose), and 0.454 8 (lignin), suggesting that removal of the phenolic barriers enhanced reducing sugar yield, and the efficiency of fungal pretreatment was comparable with that after alkali treatment, resulting a higher proportion of glucose in the hydrolysates. 展开更多
关键词 PRETREATMENT reducing sugars white-rot fungi Fourier transform infrared
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Effects of surface modification by Ni, Ti and B on electrochemical properties of Mg_(1.8)Cu_(0.2)Ni hydrogen storage alloy
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作者 焦晓燕 WANG Chang-qing +1 位作者 ZHAO Na ZHU Gui-qin 《Journal of Chongqing University》 CAS 2012年第4期177-182,共6页
Amorphous alloy Mg1.8Cu0.2Ni was successfully prepared by mechanical alloying (MA) and a series of (n-x)Ni- x(Ti+B) composites were synthesized by MA. The electrochemical properties of Mgl.8Cu0.2Ni coated by Ni... Amorphous alloy Mg1.8Cu0.2Ni was successfully prepared by mechanical alloying (MA) and a series of (n-x)Ni- x(Ti+B) composites were synthesized by MA. The electrochemical properties of Mgl.8Cu0.2Ni coated by Ni, Ti and B were studied by cyclic charge-discharge, linear polarization curve, and hydrogen diffusion coefficient experiments. Experimental results indicate that Mg1.8Cu0.2Ni-[0.9Ni0.6(Ti+B)] composite which was MA 30 h exhibited the best performance and its initial discharge capacity arrived to 714.1 mAh/g. After 30 cycles the discharge capacity was above 530 mAh/g, which was much higher than that of Mg1.8Cu0.2Ni. And after 100 cycles it holded still 442.1 mAh/g. On all accounts, after modification by Ni, Ti and B, the initial discharge capacity and high-rate discharge ability of the electrode were evidently increased. At the same time, the cycle performance was also improved significantly. 展开更多
关键词 hydrogen storage alloy mechanical alloying method surface modification MgNi-NiTiB
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A QoS-aware scheduling algorithm for combined-input-crosspoint-queued switch
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作者 徐宁 WANG Xue-shun 《Journal of Chongqing University》 CAS 2012年第4期161-166,共6页
In this paper, we study the quality of service requirement and guaranteed-rate scheduling problem for combined-input-crosspoint-queued (CICQ) switches. Using crosspoint buffers between input queues and output ports, t... In this paper, we study the quality of service requirement and guaranteed-rate scheduling problem for combined-input-crosspoint-queued (CICQ) switches. Using crosspoint buffers between input queues and output ports, the input and output scheduling can be decoupled in CICQ switches. Here we propose a new guaranteed-rate scheduling algorithm which is divided seperately into input and output scheduling. Simulation results show that our algorithm can perform better than existing scheduling schemes in both packet loss and jitter control. 展开更多
关键词 combined-input-crosspoint-queued switch guaranteed-rate scheduling low jitter quality of service
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Numerical simulation and structure improvement of double throttling in a high parameter pressure reducing valve 被引量:12
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作者 Zhi-jiang JIN Lin WEI +2 位作者 Li-long CHEN Jin-yuan QIAN Ming ZHANG 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2013年第2期137-146,共10页
In this paper, a new pressure reducing valve (PRV) with an orifice plate is proposed. The main objective is to explain the mechanisms of pressure reduction and energy conversion in the new PRV. A numerical simulatio... In this paper, a new pressure reducing valve (PRV) with an orifice plate is proposed. The main objective is to explain the mechanisms of pressure reduction and energy conversion in the new PRV. A numerical simulation method was used to investigate the PRV internal flow field and to analyze the throttling effects of the orifice plate and the transform of thermal parameters as outlet pressure, outlet temperature, velocity, and superheat. A structure improvement method for the valve body and orifice plate is put forward to reduce energy loss. The governing equations for internal flow numerical simulation are composed of the continuity, momentum, energy and k-e transport equations, based on isotropic eddy viscosity theory. Different valve plug displacement models were built to describe the double throttling process. Our analysis shows that the steam pressure drops twice and the degree of superheat increases. There are also lots of eddies which clog the flow channel and disturb the steam flow in the valve cavity after the valve plug and the outlet cavity. After modifying the structure, the numerical results show a better performance of steam flow. 展开更多
关键词 Numerical simulation Pressure and temperature reducing system Pressure reducing valve (PRV) Double throttling Structural improvement
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2D and 3D stability analysis of slurry trench in frictional/cohesive soil 被引量:13
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作者 Chang-yu HAN Jin-jian CHEN +1 位作者 Jian-hua WANG Xiao-he XIA 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2013年第2期94-100,共7页
A 2D and 3D kinematically admissible rotational failure mechanism is presented for homogeneous slurry trenches in frictional/cohesive soils.Analytical approaches are derived to obtain the upper bounds on slurry trench... A 2D and 3D kinematically admissible rotational failure mechanism is presented for homogeneous slurry trenches in frictional/cohesive soils.Analytical approaches are derived to obtain the upper bounds on slurry trench stability in the strict framework of limit analysis.It is shown that the factor of safety from a 3D analysis will be greater than that from a 2D analysis.Compared with the limit equilibrium method,the limit analysis method yields an unconservative estimate on the safety factors.A set of examples are presented in a wide range of parameters for 2D and 3D homogeneous slurry trenches.The factor of safety increases with increasing slurry and soil bulk density ratio,cohesion,friction angle,and with decreasing slurry level depth and trench depth ratio,trench width and depth ratio.It is convenient to assess the safety for the homogeneous slurry trenches in practical applications. 展开更多
关键词 Limit analysis STABILITY Slurry trench Diaphragm wall
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Progressive failure analysis of slope with strain-softening behaviour based on strength reduction method 被引量:10
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作者 Ke ZHANG Ping CAO Rui BAO 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2013年第2期101-109,共9页
Based on the strength reduction method and strain-softening model,a method for progressive failure analysis of strain-softening slopes was presented in this paper.The mutation is more pronounced in strain-softening an... Based on the strength reduction method and strain-softening model,a method for progressive failure analysis of strain-softening slopes was presented in this paper.The mutation is more pronounced in strain-softening analysis,and the mutation of displacement at slope crest was taken as critical failure criterion.An engineering example was provided to demonstrate the validity of the present method.This method was applied to a cut slope in an industry site.The results are as follows:(1) The factor of safety and the critical slip surface obtained by the present method are between those by peak and residual strength.The analysis with peak strength would lead to non-conservative results,but that with residual strength tends to be overly conservative.(2) The thickness of the shear zone considering strain-softening behaviour is narrower than that with non-softening analysis.(3) The failure of slope is the process of the initiation,propagation and connection of potential failure surface.The strength parameters are mobilized to a non-uniform degree while progressive failure occurs in the slope.(4) The factor of safety increases with the increase of residual shear strain threshold and elastic modulus.The failure mode of slope changes from shallow slip to deep slip.Poisson's ratio and dilation angle have little effect on the results. 展开更多
关键词 Shear strength reduction STRAIN-SOFTENING Peak strength Residual strength Progressive failure analysis
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Analytical model of vertical vibrations in piles for different tip boundary conditions:parametric study and applications 被引量:10
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作者 Ning WANG Kui-hua WANG Wen-bing WU 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2013年第2期79-93,共15页
In this paper,a model named fictitious soil pile was introduced to solve the boundary coupled problem at the pile tip.In the model,the soil column between pile tip and bedrock was treated as a fictitious pile,which ha... In this paper,a model named fictitious soil pile was introduced to solve the boundary coupled problem at the pile tip.In the model,the soil column between pile tip and bedrock was treated as a fictitious pile,which has the same properties as the local soil.The tip of the fictitious soil pile was assumed to rest on a rigid rock and no tip movement was allowed.In combination with the plane strain theory,the analytical solutions of vertical vibration response of piles in a frequency domain and the corresponding semi-analytical solutions in a time domain were obtained using the Laplace transforms and inverse Fourier transforms.A parametric study of pile response at the pile tip and head showed that the thickness and layering of the stratum between pile tip and bedrock have a significant influence on the complex impedances.Finally,two applications of the analytical model were presented.One is to identify the defects of the pile shaft,in which the proposed model was proved to be accurate to identify the location as well as the length of pile defects.Another application of the model is to identify the sediment thickness under the pile tip.The results showed that the sediment can lead to the decrease of the pile stiffness and increase of the damping,especially when the pile is under a low frequency load. 展开更多
关键词 Soil-pile interaction Complex impedance Pile tip Vertical vibration SEDIMENT
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Investigation of low-cycle fatigue behavior of austenitic stainless steel for cold-stretched pressure vessels 被引量:7
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作者 Cun-jian MIAO Jin-yang ZHENG +4 位作者 Xiao-zhe GAO Ze HUANG A-bin GUO Du-yi YE Li MA 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2013年第1期31-37,共7页
Cold-stretched pressure vessels from austenitic stainless steels (ASS) are widely used for storage and transportation of liquefied gases, and have such advantages as thin wall and light weight. Fatigue is an importa... Cold-stretched pressure vessels from austenitic stainless steels (ASS) are widely used for storage and transportation of liquefied gases, and have such advantages as thin wall and light weight. Fatigue is an important concern in these pressure vessels, which are subjected to alternative loads. Even though several codes and standards have guidelines on these pressure vessels, there are no relevant design methods on fatigue failure. To understand the fatigue properties of ASS 1.4301 (equivalents include UNS $30400 and AISI 304) in solution-annealed (SA) and cold-stretched conditions (9% strain level) and the response of fatigue properties to cold stretching (CS), low-cycle fatigue (LCF) tests were performed at room temperature, with total strain amplitudes ranging from :~0.4% to "0.8%. Martensite transformations were measured during the tests. Comparisons on cyclic stress response, cyclic stress-strain behavior, and fatigue life were carried out between SA and CS materials. Results show that CS reduces the initial hardening stage, but prolongs the softening period in the cyclic stress response. Martensite transformation helps form a stable regime and subsequent secondary hardening. The stresses of monotonic and cyclic stress-strain curves are improved by CS, which leads to a lower plastic strain and a much higher elastic strain. The fatigue resistance of the CS material is better than that of the SA material, which is approximately 1 - 103 to 2 - 104 cycles. The S-N curve of the ASME standard for ASS is compared with the fatigue data and is justified to be suitable for the fatigue design of cold-stretched pressure vessels. However, considering the CS material has a better fatigue resistance, the S-N curve will be more conservative. The present study would be helpful in making full use of the advantages of CS to develop a new S-N curve for fatigue design of cold-stretched pressure vessels. 展开更多
关键词 Cold stretching (CS) Austenitic stainless steel (ASS) Pressure vessels Low-cycle fatigue (LCF) Cyclic stressresponse (CSR) Fatigue life S-N curve
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Identification of waterflooded zones and the impact of waterflooding on reservoir properties of the Funing Formation in the Subei Basin,China 被引量:4
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作者 Peng-hui ZHANG Jin-liang ZHANG +6 位作者 Wei-wei REN Jun XIE Ming LI Jing-zhe LI Fang DING Jin-kai WANG Zi-rui DONG 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2013年第2期147-154,共8页
This paper describes the identification of waterflooded zones and the impact of waterflooding on reservoir properties of sandstones of the Funing Formation at the Gao 6 Fault-block of the Gaoji Oilfield,in the Subei B... This paper describes the identification of waterflooded zones and the impact of waterflooding on reservoir properties of sandstones of the Funing Formation at the Gao 6 Fault-block of the Gaoji Oilfield,in the Subei Basin,east China.This work presents a new approach based on a back-propagation neural network using well log data to train the network,and then generating a cross-plot plate to identify waterflooded zones.A neural network was designed and trained,and the results show that the new method is better than traditional methods.For a comparative study,two representative wells at the Gao 6 Fault-block were chosen for analysis:one from a waterflooded zone,and the other from a zone without waterflooding.Results from this analysis were used to develop a better understanding of the impact of waterflooding on reservoir properties.A range of changes are shown to have taken place in the waterflooded zone,including changes in microscopic pore structure,fluids,and minerals. 展开更多
关键词 WATERFLOODING Reservoir properties Neural network Gao 6 Fault-block Gaoji Oilfield
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Ultimate strength of single shear bolted connections with cold-formed ferritic stainless steel 被引量:3
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作者 Jin-seong LIM Tae-soo KIM Seung-hun KIM 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2013年第2期120-136,共17页
This paper is focused on the structural behavior of the single shear bolted connections with thin-walled ferritic stainless steel.The purpose of this study is to investigate the ultimate behaviors,such as ultimate str... This paper is focused on the structural behavior of the single shear bolted connections with thin-walled ferritic stainless steel.The purpose of this study is to investigate the ultimate behaviors,such as ultimate strength and fracture mode of the single shear bolted connections of thin-walled ferritic stainless steel(low cost steel) rather than austenitic stainless steel(high cost steel).Bolt arrangement and end distance parallel to the direction of applied load are considered as main variables of the test specimens for bolted connections.Specimens have a constant dimension of edge distance perpendicular to the loading direction,bolt diameter,pitch,and gauge.A monotonic tensile test for specimens has been carried out and some bolted connections with long end distance showed curling(out of plane deformation) occurrence which led to strength reduction.The ultimate behaviors such as fracture mode,ultimate strength are compared with those predicted by current design codes.Further,conditions of curling occurrence and the strength reduction due to curling are investigated and modified strength equations are suggested considering the curling effect. 展开更多
关键词 Cold-formed ferritic stainless steel Bolted connection Bolt arrangement End distance CURLING Strength reduction
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Chloride content and pH value in the pore solution of concrete under carbonation 被引量:7
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作者 Xiao-mei WAN Folker H. WITTMANN +1 位作者 Tie-jun ZHAO Hong FAN 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2013年第1期71-78,共8页
Chloride content and the pH value of the pore solution in the neighborhood of steel reinforcement are decisive pa- rameters for initiation and rate of corrosion. The pore solution of cement mortar and hardened cement ... Chloride content and the pH value of the pore solution in the neighborhood of steel reinforcement are decisive pa- rameters for initiation and rate of corrosion. The pore solution of cement mortar and hardened cement paste has been expressed from the pore space by high pressure in the investigation. The influence of the water-cement ratio, age, and addition of chloride to the fresh mix on chloride content in the pore solution has been determined by ion chromatography. At the same time the pH value of the pore solution has been determined. The dissolved chloride content decreases with increase in the water-cement ratio. The amount of bound chloride increases with time, but it decreases with decreasing content of dissolved chloride in the pore solution. A significant influence of carbonation on the dissolved chloride content of the pore solution has been observed. With complete carbonation, the dissolved chloride content in cement mortar and hardened cement paste increases by a factor between 2 and 12. The bound chloride decreases by 27%--54%. As expected, the pH value decreases from around 13.2 to as low as 8.0 due to car- bonation. It can be concluded that carbonation not only lowers the pH value but liberates bound chloride. This is one obvious reason why the combined action of chloride penetration and carbonation accelerates steel corrosion and shortens the service life of reinforced concrete structures. 展开更多
关键词 CHLORIDE Pore solution CARBONATION pH value
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Optimization design of the stratospheric airship's power system based on the methodology of orthogonal experiment 被引量:7
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作者 Jian LIU Quan-bao WANG +3 位作者 Hai-tao ZHAO Ji-an CHEN Ye QIU Deng-ping DUAN 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2013年第1期38-46,共9页
The optimization design of the power system is essential for stratospheric airships with paradoxical requirements of high reliability and low weight. The methodology of orthogonal experiment is presented to deal with ... The optimization design of the power system is essential for stratospheric airships with paradoxical requirements of high reliability and low weight. The methodology of orthogonal experiment is presented to deal with the problem of the optimization design of the airship's power system. Mathematical models of the solar array, regenerative fuel cell, and power management subsystem (PMS) are presented. The basic theory of the method of orthogonal experiment is discussed, and the selection of factors and levels of the experiment and the choice of the evaluation function are also revealed. The proposed methodology is validated in the optimization design of the power system of the ZhiYuan-2 stratospheric airship. Results show that the optimal configuration is easily obtained through this methodology. Furthermore, the optimal configuration and three sub-optimal configurations are in the Pareto frontier of the design space. Sensitivity analyses for the weight and reliability of the airship's power system are presented. 展开更多
关键词 Stratospheric airship Power system Orthogonal experiment OPTIMIZATION
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Some characterizations of the integrable Teichmller space 被引量:2
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作者 TANG ShuAn 《Science China Mathematics》 SCIE 2013年第3期541-551,共11页
In this paper, we prove that the Bers projection of the integrable Teichmller space is holomorphic. By using the Douady-Earle extension, we obtain some characterizations of the integrable Teichmller space as well as t... In this paper, we prove that the Bers projection of the integrable Teichmller space is holomorphic. By using the Douady-Earle extension, we obtain some characterizations of the integrable Teichmller space as well as the p-integrable asymptotic affine homeomorphism. 展开更多
关键词 integrable Teichmuller space Bers projection Douady-Earle extension p-integrable asymptotic affine homeomorphism
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Optimal arrangement of viscoelastic dampers for seismic control of adjacent shear-type structures 被引量:3
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作者 Xiao HUANG Hong-ping ZHU 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2013年第1期47-60,共14页
The optimal arrangement of viscoelastic dampers (VEDs) used to link two adjacent shear-type structures under seismic excitation was investigated. A two-step optimal design method is proposed. First, optimal parameter ... The optimal arrangement of viscoelastic dampers (VEDs) used to link two adjacent shear-type structures under seismic excitation was investigated. A two-step optimal design method is proposed. First, optimal parameter expressions of the Kelvin model are used to calculate the optimal stiffness and damping coefficient of the VEDs. Then, using the two-step optimal design method, taking the quadratic performance index as the optimization objective, the optimal arrangement of the dampers is determined. General rules about the optimal arrangement of the VEDs were obtained. The results show that the placement of only one damper between two adjacent shear-type structures should be avoided; if more than one damper is used, they should be distributed on the top and lower floors of the structures. Optimization of the number of dampers had little effect on response reduction. The most important factor was the optimization of the placement of the dampers. Through comparative study, for buildings of equal and unequal heights, the optimal parameters of dampers from parametric studies were shown to match the theoretical results for different numbers and placements of dampers. The level of response reduction was shown to be sensitive to the damping coefficient of the dampers. 展开更多
关键词 Adjacent shear-type structures Viscoelastic damper (VED) Optimal arrangement Seismic response
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Application of digital image correlation to full-field measurement of shrinkage strain of dental composites 被引量:3
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作者 Jian-ying LI Andrew LAU Alex S. L. FOK 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2013年第1期1-10,共10页
Objectives: Polymerization shrinkage of dental composites remains a major concern in restorative dentistry because it can lead to micro-cracking of the tooth and debonding at the tooth-restoration interface. The aim ... Objectives: Polymerization shrinkage of dental composites remains a major concern in restorative dentistry because it can lead to micro-cracking of the tooth and debonding at the tooth-restoration interface. The aim of this study was to measure the full-field polymerization shrinkage of dental composites using the optical digital image correlation (DIC) method and to evaluate how the measurement is influenced by the factors in experiment setup and image analysis. Methods: Four commercial dental composites, Premise Dentine, Z 100, Z250 and Tetric EvoCeram, were tested. Composite was first placed into a slot mould to form a bar specimen with rectangular-section of 4 mmx2 mm, followed by the surface painting to create irregular speckles. Curing was then applied at one end of the specimen while the other part were covered against curing light for simulating the clinical curing condition of composite in dental cavity. The painted surface was recorded by a charge-coupled device (CCD) camera before and after curing. Subsequently, the volumetric shrinkage of the specimen was calculated with specialist DIC software based on image cross correlation. In addition, a few factors that may influence the measuring accuracy, including the subset window size, speckle size, illumination light and specimen length, were also evaluated. Results: The volumetric shrinkage of the specimen generally decreases with increasing distance from the irradiated surface with a conspicuous exception being the composite Premise Dentine as its maximum shrinkage occurred at a subsurface distance of about 1 mm instead of the irradiated surface. Z100 had the greatest maximum shrinkage strain, followed by Z250, Tetric EvoCeram and then Premise Dentine. Larger subset window size made the shrinkage strain contour smoother. But the cost was that some details in the heterogeneity of the material were lost. Very small subset window size resulted in a lot of noise in the data, making it difficult to discern the general pattern in the strain distribution. Speckle size did not seem to have obvious effect on the volumetric shrinkage strain along specimen length; however, larger speckles resulted in higher level of noise or heterogeneity in the shrinkage distribution. Compared with bright illumination, dimmer lighting produced larger standard deviations in the measured shrinkage~ indicating a higher level of noise. The longer the specimen, the greater was the rate of reduction with distance from the irradiated surface, especially for the longitudinal strain. Significance: The image correlation method is capable of producing full-field polymerization shrinkage of dental composites. The accuracy of the measurements relies on selection of optimal parameters in experimental setup and DIC analysis. 展开更多
关键词 Image correlation Dental composite Polymerization shrinkage Depth of cure
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