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总结了关于考虑下部支承影响的网壳结构强震失效研究的最新研究成果。介绍了基于响应的荷载域全过程分析方法;通过建立精细化的数值模型,对考虑下部支承结构的单层球面网壳在强震作用下的特征响应进行了分析,得到了考虑下部支承结构的单层球面网壳在强震作用下的失效特征;通过大规模参数分析,详细地阐述了下部支承结构对网壳结构失效极限荷载的影响;提出了对于耦合体系的简化分析方法并初步研究了非线性下部支承结构对网壳结构失效的影响;讨论了下部支承结构非线性对网壳结构响应的影响。研究表明,非线性材料的支承结构也将明显改变耦合体系的响应规律及失效模式。

空间结构中常用的节点多数都是介于刚接和铰接之间的一种半刚性节点。国内对用于空间结构中的半刚性节点以及半刚性节点网壳的研究目前还比较少。基于半刚性节点的试验研究,得到了螺栓球半刚性节点在弯矩荷载和压弯荷载共同作用下的弯矩-转角曲线。利用大型通用有限元分析软件ANSYS建立了用于空间半刚性网壳结构的有限元分析模型。最后,将由试验得到的节点的弯曲刚度带入半刚性凯威特单层网壳的数值模型中,考虑几何参数和节点刚度对半刚性网壳稳定性的影响,展开了大规模的弹塑性全过程分析,通过系统的参数分析,较为全面地掌握了半刚性单层网壳的稳定性能,并进一步总结得出了螺栓球半刚性节点单层球面网壳的稳定承载力公式。

为揭示单层球面网壳结构在静力均布荷载作用下的失稳模式与失效机理,预测结构可能发生的破坏模式和承载能力,基于双重非线性全过程分析理论,采用ANSYS软件对典型球面网壳结构开展稳定性参数分析,系统考察结构的荷载-位移全过程曲线、塑性发展分布、屈曲模态等特征响应。并以典型算例为代表,从宏观和微观两个方面诠释了单层球面网壳结构可能发生的3种失稳模式:弹性失稳、弹塑性提前失稳、弹塑性失稳。指出弹塑性提前失稳是由于结构强度破坏诱发的一类承载力偏低的失稳模式,为提高结构安全性,在网壳稳定性设计阶段中应避免出现此类失稳模式。

Copyright of Chemical Engineering (China) / Huaxue Gongcheng is the property of Hualu Engineering Science & Technology Co Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Copyright of Feed Research is the property of Editorial Board of Feed Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Bulletin of the Chinese Ceramic Society is the property of Bulletin of the Chinese Ceramic Society Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Asian Journals of Ecotoxicology is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Engineering Mechanics / Gongcheng Lixue is the property of Engineering Mechanics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Engineering Mechanics / Gongcheng Lixue is the property of Engineering Mechanics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Snow engineering for buildings is a new academic discipline, which aims to investigate and forecast the influence of snowfalls on buildings and surroundings as well as the possibility of the disaster such as buildings collapse induced by snow accumulation, based on interdisciplinary researches such as physics, geophysics and catastrophology etc. This paper presents an in-depth review and analysis on the development of three main research methods, namely, field measurement, experimental research and numerical simulation. In terms of the field measurement, the development and theoretical models of several important factors, including snow transport by wind and snow melt by heat transfer, are investigated; the focus of this method in China in the future is also pointed out. Four different research techniques involved in experiments and the establishment of their similarity criterions as well as the selection of relevant parameters are summarized, followed by the necessity of establishing the professional climatic wind tunnel for snow drift research. By reviewing the progress of the computational fluid dynamics (CFD) simulation method, the achievement of existing simulation methods and their potentials shortcomings are summarized so as to show the direction of the future improvements in this research method. [ABSTRACT FROM AUTHOR]

Copyright of Engineering Mechanics / Gongcheng Lixue is the property of Engineering Mechanics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

目的分析PCR-限制性片断长度多态性(PCR-RFLP)技术和结合SYBR GreenⅠ荧光染料的实时荧光PCR技术检测HBV拉米夫定耐药基因的效果。方法采用PCR-RFLP技术和结合SYBR GreenⅠ荧光染料的实时荧光PCR技术检测186例份乙肝血清标本拉米夫定耐药HBV DNA聚合酶204、180位点基因突变情况,并进行DNA测序验证。结果两种方法在HBV DNA聚合酶204位点均检出YIDD、YVDD、YMDD/YIDD、YMDD/YVDD、YIDD/YVDD突变类型,未检测出YSDD突变类型,检测结果与DNA测序验证结果比较差异均无统计学意义(χ~2=2.101、1.614,P均>0.05)。两种方法在HBV DNA聚合酶180位点均检出L180M、L180M+M204I、L180M+M204V突变类型,检测结果与DNA测序验证结果比较差异均无统计学意义(χ~2=0.054、1.614,P均>0.05)。结论 PCR-RFLP技术和结合SYBR GreenⅠ荧光染料的实时荧光PCR技术均可用于HBV拉米夫定耐药基因突变检测,但后者更适合大规模耐药基因突变筛查。 [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Small sample size effect affects the accuracy of the extreme value analysis results. Various techniques could be applied to reduce this effect, including the regional frequency analysis (RFA). An application of RFA to estimate the ground snow load using annual maximum snow depth records from 83 meteorological stations in Heilongjiang province was presented. The estimated extreme values were compared with those obtained from on-site analysis. Moreover, Monte-Carlo technique was employed to assess the adequacy of the RFA versus the on-site analysis to estimate the extreme snow depth or snow load. Judging based on root-mean-square-error and the bias obtained from the simulation analysis, it is concluded that the RFA is preferred, especially when the sample size is relatively small. The snow load contour maps are developed for the province by using return period values of annual maximum snow load estimated by three different approaches, indicating that the approach recommended by the Chinese design code is relatively conservative. [ABSTRACT FROM AUTHOR]

To study the seismic response and the ultimate strength of super-large span reticulated domes accurately, an analysis about the seismic response of super-large span reticulated dome (800 m span) using the time-history analytic method was made considering complexity effects such as ground motion with spatial coherency and wave-passage effect, soil-structure interaction and material damage accumulation. Results show that the complexity effects can influence the seismic performance of super-large span reticulated domes. By comparing the failure modes of structures under uniform excitation and multi-support excitation, it is found that the multi-support excitations increase the internal forces of outer members, while decreasing those of inner members. Therefore, the outer members fail earlier, and the failure mode was changed which severely weakens the ultimate strength of the structure. The soil-structure interaction effect and material damage accumulation effect both increase the magnitude of seismic responses of a structure to different extent. The soil-structure interaction effect amplifies the influence of seismic action on structure, and material damage accumulation effect influences the structure obviously when the seismic amplitude is high. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper proposes a novel semi-rigid C-joint for spatial lattice structures. In order to increase the torsional stiffness and energy-dissipating capacity of the C-joint, a joint with ' strong connection and weak plate' is proposed based on the conventional seismic principle ' strong joint and weak member'. Firstly，rational dimensions of the components were determined preliminarily through relative specifications and theoretical analysis ； secondly, the nonlinear finite element model was established using the finite element software ABAQUS ； thirdly, the rational dimensions of the joint components were determined through the optimization analysis carried out on the finite element model. At last, the experimental study was carried out on the proposed C-joint to investigate its mechanical characteristics. It is shown that ： the proposed novel joint provides favorable ductility and torsional stiffness ； the stiffness and ultimate bending of the joints increase with the increasing of the thickness of the side plate and front plate ； the material constitutive model for the cone head of the joint affects the simulation results greatly and the trilinear material constitutive model is proper for the simulation. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The research results on super-large span structures based on various types of structural system are reviewed and the development tendency of the structure is proved. Static behaviors of double-layer reticulated shell, local triplelayered reticulated shell, ribbed type mega-latticed and Kiewitt type mega-latticed structures with the same geometrical parameters (800 m span) and load were compared. The results show that Kiewitt type mega-latticed structures have best mechanical performance with the same span and loads. Then, for the space complexity of this structure, the structural configuration was analyzed through CAD 3D modeling and seven key structural form parameters, such as span, rise and height of truss, were determined. Furthermore innovative structural-programming method based on geometrical configuration was conducted，and the mechanical performance of Kiewitt type mega-latticed structures was studied based on the program which can create the structure automatically by APDL parametric language. A great number of parametric evaluations including 153 models and more than one thousand examples were studied for seven parameters, including circumferential/radial divisions, rise-span ratio and height-span ratio of truss. The mechanical property with the variation of the parameters and the reasonable value range of every parameter were summarized. The study is the basis of further research and guidance for actual engineering design. [ABSTRACT FROM AUTHOR]

Wind tunnel test and numerical modeling technique are often used to estimate the drifting snow profile. One of the basic parameters needed for the estimation is the input wind speed. The selection of this wind speed is of importance since it affects the estimated drifting snow profile significantly. In this study, annual maximum snow depth and the daily maximum wind speed on its occurrence (companion wind speed) between 1981 and 2010 from all the meteorological stations in Heilongjiang province, as well as annual maximum wind speed for part of the stations, were used to evaluate the possible input wind speed. For this purpose, statistical analysis of the probable month of occurrence for annual maximum snow depth and for annual maximum wind speed were first carried out, followed by the assessment of correlation between annual maximum snow depth and its companion (daily maximum) wind speed. It is suggested that the input wind speed can be assigned with the mean of the companion wind speed. By evaluating the input wind speed for Heilongjiang province, it is concluded that the companion wind speed is much less than the annual maximum wind speed, and that the ratio of the former to the latter is about 0.45. Based on this finding, it is suggested that the input wind speed for estimating difting snow profile can be set to be 0. 45 times of the 50-year return period value of annual maximum wind speed when meteorological data is not available for the analysis. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

目的 探讨清肠合剂保留灌肠防治腹部手术后肠粘连的临床效果。方法 选择行腹部手术患者60例,随机分为观察组、对照组各30例。两组术后均给予禁食、补液、抗感染等对症支持治疗,必要时行持续胃肠减压、胃肠外营养;观察组在此基础上给予清肠合剂保留灌肠,连续灌肠1周。记录治疗期间两组首次出现肠鸣音时间、首次排气时间、首次排便时间,以及术后7天发生切口感染、切口裂开、肺部感染等并发症情况。术后随访1年,观察两组肠粘连发生情况。结果与对照组比较,观察组术后首次出现肠鸣音时间、首次排气时间、首次排便时间均明显缩短(P均<0.05),两组术后切口感染、切口裂开及肺部感染发生率比较P均>0.05。术后随访1年,观察组发生肠粘连5例,对照组16例,两组比较P<0.05。结论 清肠合剂灌肠可促进腹部手术后胃肠功能恢复,预防肠粘连发生。 [ABSTRACT FROM AUTHOR]

In order to explore the influence of the building thermal environment on the roof snow load, a prefabricated building model for actual measurement was designed based on the requirement of the law of thermal coefficient (Ct) in foreign building load codes (ASCE/ SEI 7-10 and ISO 4355: 2013). The proposed model can change the heat resistance of roof and indoor temperature. In detail, the actual measurements of apparent density of snow and snow load under natural snow (with low moisture) and artificial snow (with high moisture) conditions in both the snowmelt period (with daily maximum temperature higher than 0 °C) and the non-snowmelt period (with daily maximum temperature not higher than 0 °C) were completed. The results show that the snow-layer on the building roof in the snowmelt period experiences the stages of the melt of lower surface snow, and then upward movement of melt layer with discharge of the snowmelt water. The apparent density and environmental temperature of snow show a positively correlated relationship while the variation of snow load appears a typical three-stage form, including the melting, the mass -loss and the recrystallization. Besides, the variation of snow-layer on the building roof in the non-snowmelt period is less than that in the snowmelt period, but the trend is highly consistent, where the snow load decreases with the increasing of roof heat loss. Finally, according to GB 50189-2015 and JGJ 134-2010, the thermal coefficient values of all measured conditions were calculated, and the C, value of the building with the indoor maximum temperature about 0 °C was suggested to be 1. 2. [ABSTRACT FROM AUTHOR]

Step roofs are sensitive to snow loads, therefore, snow distribution on lower roof of step roofs with gable-roof on the high part was studied through model experiment. The model experiments were conducted in open air snow-wind combined laboratory developed by the Harbin Institute of Technology, which could simulate the process of natural snowfall. The experiments consisted of four models according to different slopes of the upper gable-roof, and were conducted in different wind velocities and directions. The reliability of the experiment results was verified through comparison of field measurements and experiments on step flat roofs. The results show that the higher the wind velocity, the more significant the unevenness of snow distribution, but the roof snow distribution coefficient does not increase with the wind velocity. The slope of the upper gable-roof has significant influence on snow distribution. For the model which has 60° gable roofs and is under a wind of 3m/s from the windward side, the maximum snow distribution coefficient is 7.9 which is beyond the value in Eurocode. [ABSTRACT FROM AUTHOR]

Wind-induced snowdrift phenomenon leads to the unbalanced distribution of snow on the building roofs, which could bring a huge safety hazard to the structure. The wind tunnel test is one of the main methods to study wind-induced snowdrift, and similarity theories are the bases of wind tunnel test. In this paper, the similarity theories of Kind, Iversen and Tabler were firstly summarized. After the classification, the main similarity criteria were then summarized, including Froude, Reynold, time similarity criterion and speed similarity criterion, etc. Making use of the wind-snow combined experiment facility, taking artificial snow as the simulating granular material, as well as considering characteristics of different similarity criteria sufficiently, scale experiments on snow distribution around a 0.5 m cube were conducted according to the selected similarity criterion, with the field observation on snow distribution around a 1 m cube by Oikawa as the prototypes. Finally, according to the comparison of the prototypes and scale experiments, and with a full consideration of the characteristics of each similarity criterion, the similarity criterion based on the mass transfer rate of saltation process is proved lo be the most reliable for the reappearance of snow distribution, and the experimental result show better agreement with the prototype when using the mean wind speed of the prototype. [ABSTRACT FROM AUTHOR]