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Specification and Verification for Semi-Structured Data
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作者 CHEN Tao-lue HAN Ting-ting LU Jian 《Wuhan University Journal of Natural Sciences》 EI CAS 2006年第1期107-112,共6页
Tree logic, inherited from ambient logic, is introduced as the formal foundation of related programming language and type systems, In this paper, we introduce recursion into such logic system, which can describe the t... Tree logic, inherited from ambient logic, is introduced as the formal foundation of related programming language and type systems, In this paper, we introduce recursion into such logic system, which can describe the tree data more dearly and concisely. By making a distinction between proposition and predicate, a concise semantics interpretation for our modal logic is given. We also develop a model checking algorithm for the logic without △ operator. The correctness of the algorithm is shown. Such work can be seen as the basis of the semi-structured data processing language and more flexible type system. 展开更多
关键词 semi structured data tree logic FIXPOINT model checking algorithm
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Factors Affecting Japanese HPV-Vaccination: Findings from the Semi-Structured Interviews with Adolescent Girls and Caregivers
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作者 Rie Wakimizu Kaori Nishigaki +4 位作者 Hiroshi Fujioka Koji Maehara Haruo Kuroki Tadashi Saito Katsuya Uduki 《Health》 2014年第13期1602-1615,共14页
The objective of the present study was to qualitatively assess the obstructive and facilitative factors affecting adolescent girls and their caregivers when the adolescent had received or was considering receiving the... The objective of the present study was to qualitatively assess the obstructive and facilitative factors affecting adolescent girls and their caregivers when the adolescent had received or was considering receiving the Human Papilloma Virus (HPV) vaccination. Using these data, we propose recommendations for medical and nursing staff concerned with HPV vaccination. Participants were 20 adolescent girls (aged 10 - 19 years) and their caregivers, who had visited any of the 3 pediatric clinics in the Tokyo metropolitan area during a specified period since HPV vaccination began in Japan. The girls and their caregivers were separately interviewed by 2 child and/or family nursing care specialists with a semi-structured interview. The responses were qualitatively analyzed by 2 specialists, and the obstructive and facilitative factors affecting participants’ decision to receive HPV vaccination were extracted from the responses. Among the 20 sets of participants, 7 adolescents had completed HPV vaccination, 9 were going to receive vaccination, and 4 had not received any vaccination. The obstructive/facilitative factors related to considering or receiving HPV vaccination and actual vaccination were extracted and 4 main categories of factors were identified. Facilitators toward HPV-vaccination of daughters included clear future self-image and visions, fear Cervical Cancer (CC) and desire to escape from CC, having discussion with mothers about HPV-vaccination and CC, and to have a boyfriend. Barriers toward vaccination included the mothers’ reluctance to explain the sexual matters about HPV-vaccination to their daughters and difficulty with find the appropriate clinic or hospital to HPV-vaccination. Relevant factors about vaccination included positive family attitudes toward vaccination, having family system allowing consultation and having a public financial support for vaccination for daughters. Our conceptual model adapted from the Katz, et al. conceptual framework integrated the key barriers and facilitators as factors within each of four domains. These four domains have an important link. Especially, the environmental factors and the structural and sociocultural factors domain affect the individual adolescent and the caregiver factors domain, respectively. The results of present study suggest that medical/nursing activities centered on promoting HPV vaccination in Japan should comprehensively cover CC/vaccination/sex education in an integrated fashion, while schools and public health centers should provide opportunities for caregivers and adolescents to jointly participate in awareness education on HPV vaccination. 展开更多
关键词 Adolescents CAREGIVERS HPV VACCINATION Japan Qualitative Study semi-structured INTERVIEW
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Analysis on Fuji Apple Tree Structures and Related Factors under Different Pruning Modes 被引量:1
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作者 郝婕 索相敏 +4 位作者 李学营 魏亮 王献革 鄢新民 冯建忠 《Agricultural Science & Technology》 CAS 2017年第12期2528-2531,2535,共5页
To determine the correlations between the tree structuresof Fuji apple with different pruning modes and each factor, the data about 3 tree structures which were free spindle short shoot, free spindle long shoot and sl... To determine the correlations between the tree structuresof Fuji apple with different pruning modes and each factor, the data about 3 tree structures which were free spindle short shoot, free spindle long shoot and slenderspindle short shoot in Xingtang County of Hebai Province were investigated, then by SPSS anal- ysis, the correlations between the taperingness and each growth factor of inserted small branch were compared. The results showed that the taperingness of central trunk of free spindle dwarf-shoot Fuji apple treeshad negative correlations with each factor of inserted small branch, while the taperingness of central trunk of free spin- dle long-shoot Fuji apple treeshad positive correlations with each factor of inserted small branch, the taperingness of central trunk of slenderspindle short-shootFuji ap- ple treeshad negative correlation with total thickness of inserted small branch, but had positive correlations with other factors. This study can provide a scientifictheo- retical basis for the pruning technology of high-density planting trees grafting by dwarfing self-rooted rootstock. 展开更多
关键词 pruning Fuji apple Tree structures Analysis of related factors
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Analysis on Apple Tree Structures by Free Spindle Pruning Mode
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作者 郝婕 索相敏 +3 位作者 李学营 王献革 鄢新民 冯建忠 《Agricultural Science & Technology》 CAS 2016年第10期2238-2241,共4页
To determine the correlation between the stem taperingness and central shaft by free spindle pruning mode on different apple cultivars, the central shaft growth data of three cultivars of free spindle short shoot "F... To determine the correlation between the stem taperingness and central shaft by free spindle pruning mode on different apple cultivars, the central shaft growth data of three cultivars of free spindle short shoot "Fuji", free spindle long shoot "Fuji", free spindle "Huaguan" were investigated in Xingtang County of Hebei Province by SPSS analysis. The results showed that the stem taperingness on free spindle short shoot "Fuji" was in negative correlation with central shaft, but the correlation was not significant. While the stem taperingness on free spindle long shoot "Fuji" was in positive correlation with central shaft, but the correlation was not significant either. The stern taperingness on free spindle "Huaguan" was in negative correlation with central shaft, and the correlation between the stem taperingness and the central shaft total length was significant at the level of 0.01. The results.provided scientific theoretical basis for guiding the dwarfing rootstocks close planting apple tree pruning technology. 展开更多
关键词 APPLE Free spindle pruning mode structure analysis
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Wave Forces on Submerged Semi-Circular Breakwater and Similar Structures 被引量:15
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作者 XIE Shileng Prof. Senior Engineer, The First Design Institute of Navigation Engineering, Ministry of Communications of China, Tianjin 300222, P. R. China. 《China Ocean Engineering》 SCIE EI 1999年第1期63-72,共10页
The results of design and experiment of a submerged semi-circular breakwater at the Yangtze estuary show that the submerged structure will be unsafe when the general empirical wave force formula for semi-circular brea... The results of design and experiment of a submerged semi-circular breakwater at the Yangtze estuary show that the submerged structure will be unsafe when the general empirical wave force formula for semi-circular breakwater is used in design. Therefore, a new calculation method for the wave forces acting on a submerged semi-circular structure is given in this paper, in which the wave force acting on the inside circumference of semi-circular arch is included, and the phase modification coefficient in the general empirical formula is adjusted as well. The new wave force calculation method has been Verified by the results of seven related physical model tests and adopted in the design of the south esturary jetty of the first stage project of Deep Channel Improvement Project of the Yangtze River Estuary, the total jetty length being 17.5 km. 展开更多
关键词 semi-circular breakwater submerged structure estuary jetty wave force
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Effects of compressing and remelting in SIMA processing on semi-solid structure evolution of an Al-Zn wrought alloy 被引量:6
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作者 LIUChangming ZOUMaohua 《Rare Metals》 SCIE EI CAS CSCD 2003年第3期185-191,共7页
Structure evolution of an Al-Zn wrought alloy in remelting processing in thestrain induced melt activated (SIMA) serai-solid procedure was observed, and effects of factors, theremelting temperature, the holding time, ... Structure evolution of an Al-Zn wrought alloy in remelting processing in thestrain induced melt activated (SIMA) serai-solid procedure was observed, and effects of factors, theremelting temperature, the holding time, and the compression strain, on structures and grain sizesof the alloy were investigated. The results show that (1) the proper temperature of remelting is inthe range of 610 to 615℃; (2) the grain size in specimen with greater compression strain is smallerthan that with smaller compression strain in condition of the same remelting temperature andholding time, and the grain size in local area with great local equivalent strain is smaller thanthat with small one; (3) liquid occurs in form of cluster in matrix during remelting and itsquantity increases with remelting time increasing; liquid in specimen with great compression strainoccurs earlier than that with small one, and quantity of liquid in the center of specimen withgreater local equivalent strain is greater than that in the two ends of it; (4) distortion energyafter deforming in matrix of the alloy is the significant factor to activate melting of matrix atlocal area with great local equivalent strain. 展开更多
关键词 semi-solid structure evolution strain induced melt activated processing semi-solid remelting Al-Zn alloy
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Structural evolution of ZA27 alloy during semi-solid isothermal heat treatment 被引量:4
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作者 陈体军 马颖 +3 位作者 郝远 陆松 许广济 孙军 《中国有色金属学会会刊:英文版》 CSCD 2001年第1期98-102,共5页
The structural evolution of ZA27 alloy modified by element Zr was studied during semi solid isothermal heat treatment, and its transformation mechanism was also discussed. The results indicate that the primary α phas... The structural evolution of ZA27 alloy modified by element Zr was studied during semi solid isothermal heat treatment, and its transformation mechanism was also discussed. The results indicate that the primary α phase changes from equiaxed grains to spherical grains gradually at semi solid temperature of 460 ℃. With increasing isothermal time, the eutectic between boundaries of α phase diffuses toward α phase, and the primary equiaxed grain arms merge and boundaries tend to disappear to form near particle grains. Further, the eutectic left on α boundaries melts to make the near particle grains separate, and form spherical structure at last. [ 展开更多
关键词 ZA27 alloy semi-SOLID STATE ISOTHERMAL HEAT treatment structural evolution SPHERICAL structure
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Strength Analysis on Brace Structure for Semi-Submersible in Consideration of Wave Slamming 被引量:2
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作者 HUO Fa-li YAO Zhi +2 位作者 ZHANG Jian WANG Jun-wei DONG Bin 《China Ocean Engineering》 SCIE EI CSCD 2018年第5期536-545,共10页
Slamming on bracings of column stabilized units shall be considered as a possible limiting criterion under transit condition based on the requirements in DNV-OS-C103. However, the wave slamming loads under survival co... Slamming on bracings of column stabilized units shall be considered as a possible limiting criterion under transit condition based on the requirements in DNV-OS-C103. However, the wave slamming loads under survival condition were ignored for the strength analysis of the brace structures in many semi-submersible projects. In this paper, a method of strength analysis of brace structure is proposed based on the reconstruction and extrapolation of numerical model. The full-scale mooring system, the wind, wave and current loads can be considered simultaneously. Firstly,the model tests of the semi-submersible platform in wind tunnel and wave tanker have been carried out. Secondly,the numerical models of the platform are reconstructed and extrapolated based on the results of model tests. Then, a nonlinear numerical analysis has been conducted to study the wave slamming load on brace in semi-submersible platform through the reconstructed and extrapolated numerical model. For the randomness of wave load, ten subcases under each condition have been carried out. The value of the 90% Gumble distribution values of the ten subcases are used. Finally, the strength on brace structure has been analyzed considering the wave slamming. The wave slamming loads have been compared between the survival condition and transit condition with the method. The results indicate that wave slamming under survival condition is more critical than that under transit condition.Meanwhile, the wave slamming is significant to the structural strength of the brace. It should be overall considered in the strength analysis of the brace structure. 展开更多
关键词 semi-submersible platform wave slamming brace structure structural strength
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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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Seismic structural control using semi-active tuned mass dampers 被引量:4
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作者 杨润林 周锡元 刘锡荟 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2002年第1期111-118,共8页
This paper focuses on how to determine the instantaneous damping of the semi-active tuned mass damper (SATMD) with continuously variable damping.An off-and-towards-equilibrium (OTE) algorithm is employed to examine th... This paper focuses on how to determine the instantaneous damping of the semi-active tuned mass damper (SATMD) with continuously variable damping.An off-and-towards-equilibrium (OTE) algorithm is employed to examine the control performance of the structure/SATMD system by considering the damping as an assumptive control action.The damping modification of the SATMD is carried out according to the proposed OTE algorithm,which is formulated based on analysis of the structural movement under external excitations,and the measured responses of the structure at every time instant. As examples two numerical simulations of a five-storey and a ten-storey shear structures with a SATMD on the roof are conducted.The effectiveness on vibration reduction of MDOF systems subjected to seismic excitations is discussed.Analysis results show that the behavior of the structure with a SATMD is significantly improved and the feasibility of applying the OTE algorithm to the structural control design of SATMD is also verified. 展开更多
关键词 semi-active TMD seismic structural control MDOF off-and-towards-equilibrium algorithm
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A SEMI-ANALYTICAL AND SEMI-NUMERICAL METHOD FOR SOLVING 2-D SOUND-STRUCTURE INTERACTION PROBLEMS 被引量:8
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作者 Xiang Yu Huang Yuying (College of Civil Engineering and Mechanics,Huazhong University of Science and Technology,Wuhan 430074,China) 《Acta Mechanica Solida Sinica》 SCIE EI 2003年第2期116-126,共11页
Based on the transfer matrix method and the virtual source simulation technique, this paper proposes a novel semi-analytical and semi-numerical method for solving 2-D sound- structure interaction problems under a harm... Based on the transfer matrix method and the virtual source simulation technique, this paper proposes a novel semi-analytical and semi-numerical method for solving 2-D sound- structure interaction problems under a harmonic excitation.Within any integration segment, as long as its length is small enough,along the circumferential curvilinear coordinate,the non- homogeneous matrix differential equation of an elastic ring of complex geometrical shape can be rewritten in terms of the homogeneous one by the method of extended homogeneous capacity proposed in this paper.For the exterior fluid domain,the multi-circular virtual source simulation technique is adopted.The source density distributed on each virtual circular curve may be ex- panded as the Fourier's series.Combining with the inverse fast Fourier transformation,a higher accuracy and efficiency method for solving 2-D exterior Helmholtz's problems is presented in this paper.In the aspect of solution to the coupling equations,the state vectors of elastic ring induced by the given harmonic excitation and generalized forces of coefficients of the Fourier series can be obtained respectively by using a high precision integration scheme combined with the method of extended homogeneous capacity put forward in this paper.According to the superposition princi- ple and compatibility conditions at the interface between the elastic ring and fluid,the algebraic equation of system can be directly constructed by using the least square approximation.Examples of acoustic radiation from two typical fluid-loaded elastic rings under a harmonic concentrated force are presented.Numerical results show that the method proposed is more efficient than the mixed FE-BE method in common use. 展开更多
关键词 sound-structure interaction acoustic radiatlon multi-circular virtual source simulation technique transfer matrix method inverse fast Fourier transformation semi-analytical and semi-numerical method
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Effect of Semi-Solid Isothermal Heat Treatment on Microstructure of ZL104 Aluminum Alloy 被引量:2
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作者 Yang Mingbo Shen Jia 《稀有金属材料与工程》 SCIE EI CAS CSCD 北大核心 2009年第A03期95-99,共5页
The feasibility of fabricating ZL104 aluminum alloy with non-dendritic microstructure by semi-solid isothermal heat treatment process and the effects of holding temperature and time on the semi-solid isothermal heat-t... The feasibility of fabricating ZL104 aluminum alloy with non-dendritic microstructure by semi-solid isothermal heat treatment process and the effects of holding temperature and time on the semi-solid isothermal heat-treated microstructure of the alloy, are investigated. The research results indicate that it is possible to produce ZL104 alloy with non-dendritic microstructure by a suitable semi-solid isothermal heat treatment. After treated at 580 ℃ for 120 min, the ZL104 alloy can obtain a non-dendritic microstructure with an 49% liquid content and an average size range of 115 μm of the unmelted primary solid particles. In addition, an increase in the holding time from 30 to 120 min for a given holding temperature of 580 ℃ or in the holding temperature from 570 to 580 ℃ for a given holding time of 120 min causes the average size and globular tendency of unmelted primary solid particles in the semi-solid ZL104 alloy to decrease and become more obvious, respectively. 展开更多
关键词 铝合金 热处理过程 微观结构 物理性能
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Effects of process parameters on pore structure of semi-coke prepared by solid heat carrier with dry distillation 被引量:20
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作者 Zhou, Guoli Wu, Jianjun +5 位作者 Miao, Zhenyong Hu, Xuelian Li, Xia Shi, Xin Cai, Zhidan Shang, Yukun 《International Journal of Mining Science and Technology》 SCIE EI 2013年第3期423-427,共5页
The semi-coke was prepared by solid heat carrier with dry distillation in single factor method. The pore structures of raw coal and semi-coke were characterized by Brunauer-Emmett-Teller (BET) and scanning electron mi... The semi-coke was prepared by solid heat carrier with dry distillation in single factor method. The pore structures of raw coal and semi-coke were characterized by Brunauer-Emmett-Teller (BET) and scanning electron microscope (SEM). The results show that the adsorption and desorption isotherm of semi-coke are not coincident. There was a wide pore distribution on the semi-coke, in which mesopores and micropores account for a considerable proportion. Also there are many more secondary pores. With the increase of the final temperature of heat carrier and constant temperature, as well as the decrease of volume ratio of coal and hot carrier reactor, specific surface area and pore volume of semi-coke increased rapidly first and then decreased and finally increased, along with the rapidly reduction of average pore size. SEM photos show that the surface of semi-coke becomes increasingly rough and glossy. 展开更多
关键词 semi-coke Pore structure Heat carrier dry distillation BET SEM
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Research on semi-active control method of a building structure based on non-smooth control 被引量:2
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作者 Wang Qing Wang Jianhui Ma Kemao 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2019年第2期425-432,共8页
This study investigates the effectiveness of the non-smooth semi-active control algorithm on suppressing the vibration performance of a building structure subjected to seismic waves. According to the Lyapunov stabilit... This study investigates the effectiveness of the non-smooth semi-active control algorithm on suppressing the vibration performance of a building structure subjected to seismic waves. According to the Lyapunov stability theory, it has bene proven that the non-smooth semi-active control algorithm can achieve a finite-time stability of the vibration relative to the isolation layer of a building structure. Through numerical simulation of two buildings with different parameters subjected to the input of a seismic wave, the vibration conditions of passive control, LQR semi-active control and non-smooth semiactive control are compared and analyzed. The simulation results show that the non-smooth semi-active control algorithm has a better robustness and effectiveness in restraining the impact of earthquakes on the structure. 展开更多
关键词 building structure ISOLATION LAYER semi-ACTIVE CONTROL NON-SMOOTH CONTROL vibration
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Semi-synthesis and Crystal Structure of Sophoridine N-oxide 被引量:1
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作者 赵斌 禹洁 +3 位作者 李欣儒 龙伟 张军帅 刘培勋 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2012年第3期396-400,共5页
Sophoridine N-oxide was synthesized and characterized by 1H-NMR,EI-MS,IR and elemental analysis,together with X-ray single-crystal diffraction analysis,and its crystal structure was reported for the first time.The cry... Sophoridine N-oxide was synthesized and characterized by 1H-NMR,EI-MS,IR and elemental analysis,together with X-ray single-crystal diffraction analysis,and its crystal structure was reported for the first time.The crystal belongs to the orthorhombic system,space group P212121 with a = 8.321(2),b = 15.650(3),c = 24.352(5) ,V = 3171.1(11) 3,Z = 8,Dc = 1.258 g/cm3,λ(CuKα) = 1.54178,F(000) = 1440,the final R = 0.0351 and wR = 0.0970.The crystal structure shows Sophoridine N-oxide crystallizes with two host molecules of similar conformation and four water solvent molecules in the asymmetric unit.In the crystal structure,intermolecular O-H…O hydrogen bonds link the constituent molecules into a 2D layer structure,which further extends to a 3D supramolecular architecture via Van der Waals interactions and intermolecular O-H…O hydrogen bonds. 展开更多
关键词 semi-SYNTHESIS sophoridine N-oxide crystal structure
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Effect of deformation processing parameter on microscopic structure of Ti14 alloy under semi-solid 被引量:1
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作者 郭萍 赵永庆 吴玮璐 《中国有色金属学会会刊:英文版》 CSCD 2007年第A01期504-508,共5页
Hot compressive deformation test of Ti-Al-Cu-Si alloy was performed on Gleeble-3500 hot-Simulator over the range of deformation temperature from 1 000 to 1 300 ℃,strain rate from 0.005 s-1 to 5 s-1,deformation degree... Hot compressive deformation test of Ti-Al-Cu-Si alloy was performed on Gleeble-3500 hot-Simulator over the range of deformation temperature from 1 000 to 1 300 ℃,strain rate from 0.005 s-1 to 5 s-1,deformation degree from 40% to 70%,and samples of d 8 mm×15 mm were used. Change rules of microstructure were mainly studied. The results show that deformation temperature directly influences the nucleation growth and globurizing of grain,and with the temperature rising,the diameter of grain increases,the grain boundary widens. The effect of deformation degree on microstructure varies with deformation temperature. Equivalent diameter of grains shows a trend of falling before elevation with strain rate increasing and temperature rising. 展开更多
关键词 合金 半固体成型技术 微观结构
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Seismic protection of frame structures via semi-active control:modeling and implementation issues 被引量:1
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作者 Vincenzo Gattulli Marco Lepidi Francesco Potenza 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2009年第4期627-645,共19页
Theoretical and practical issues concerning the multi-faceted task of mitigating the latero-torsional seismic response of a prototypal frame structure with asymmetric mass distribution are approached, Chevron braces w... Theoretical and practical issues concerning the multi-faceted task of mitigating the latero-torsional seismic response of a prototypal frame structure with asymmetric mass distribution are approached, Chevron braces with embedded magnetorheological dampers acting on the interstory drift are used to ensure additional energy dissipation. The semi-active control strategy employed to govern the modification of the damper characteristics via feedback is based on the selection of optimal forces according to a H2/LQG criterion, with respect to which the actual forces are regulated by a clipped-optimal logic. A dynamic observer is used to estimate the state through a non-collocated placement of the acceleration sensors. Several aspects to be addressed throughout the complex process including the design, modelization, and implementation phases of semi-active protection systems are discussed. Finally, experimental results obtained to mitigate the motion induced by ground excitation in a large-scale laboratory prototype, simulating the seismic response of a two-story building, are summarized. 展开更多
关键词 seismic protection: flame structures semi-active control magnetorheological damper
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Microstructure Evolution of Semi-solid Processed Hyper-eutectic Al-30%Si Alloy 被引量:2
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作者 Yanjun Li Weimin Mao Xueyou Zhong(Material Science and Engineering School, University of Science and Technology Beijing, Beijing 100083, China) 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 1999年第4期259-261,共3页
An investigation was made on the influences of mechanical stirring on microstructure of hyper-eutectic Al-30%Si alloy (inmass fraction) during solidification. The primary Si crystals formed in the alloy melt were grad... An investigation was made on the influences of mechanical stirring on microstructure of hyper-eutectic Al-30%Si alloy (inmass fraction) during solidification. The primary Si crystals formed in the alloy melt were gradually changed from elongated platelets tonear-spherical shapes by mechanical stirring. The spheroidization of primary St crystals occurs by the mechanism of bending and fractureof Si platelets, wear and collision between Si crystals, and coalescence of small Si particles. The influence of under-cooling and coolingrate of the alloy melt on primary Si crystals of semi-solid processed alloys is investigated as well. The increase of under-cooling andcooling rate decreases the size of primary Si crystals. 展开更多
关键词 semi-solid state process solidification structure mechanical stirring hyper-eutectic Al-Si alloy
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Semi-Probabilistic Evaluation of System Redundancy for Existing Offshore Structures 被引量:1
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《China Ocean Engineering》 SCIE EI 1995年第1期1-8,共8页
In this paper, a new definition of structure system redundancy is proposed in view of the various measures for structure redundancy. By introducing the terms of structure system failure at the mechanism level and equi... In this paper, a new definition of structure system redundancy is proposed in view of the various measures for structure redundancy. By introducing the terms of structure system failure at the mechanism level and equivalent reliability index, the safety for existing offshore platforms can be evaluated by the semi-probabilistic method presented in this paper. Some numerical examples are given and satisfactory results have been obtained. 展开更多
关键词 residual strength semi-probabilistic method damaged structure REDUNDANCY reliability index critical value
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Study on semi-active control of mega-sub controlled structure by MR damper subject to random wind loads 被引量:7
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作者 Qin Xiangjun Zhang Xun'an Sheldon Cherry 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2008年第3期285-294,共10页
The recently proposed mega-sub controlled structure (MSCS), a new type of structure associated with the design and construction of super-tall buildings, has attracted the attention of designers for use in enhancing ... The recently proposed mega-sub controlled structure (MSCS), a new type of structure associated with the design and construction of super-tall buildings, has attracted the attention of designers for use in enhancing the control effectiveness in mega-frame buildings. In this paper, a dynamic equation and method to assemble parameter matrixes for a mega-sub controlled structure under random wind loads is presented. Semi-active control using magnetorheological dampers for the MSCS under random wind loads is investigated, and is compared with a corresponding system without dampers. A parametric study of the relative stiffness ratio and relative mass ratio between the mega-frame and the substructures, as well as the additional column stiffness ratio that influences the response control effectiveness of the MSCS, is discussed. The studies reveal, for the first time, that different control mechanisms exist. The results indicate that the proposed structure employing semi-active control can offer an effective control mechanism. Guidelines for selecting parameters are provided based on the analytical study. 展开更多
关键词 mega-sub controlled structure (MSCS) semi-active control magnetorheological damper relative stiffness ratio relative mass ratio additional column stiffness ratio wind load
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