中国省级区域餐饮业竞争力的结构方程模型

提升餐饮业竞争力日渐引起政府重视,但学界对餐饮业竞争力的理论研究仍有待深入。本文采用结构方程模型方法,对中国省级区域餐饮业竞争力进行了理论和实证研究,验证了生产要素、关联产业、需求条件和企业结构对餐饮业竞争力具有直接的、正向的、依次减弱的影响,并由此构建了中国省级区域餐饮业竞争力的结构方程模型和评价方法。     

三星堆一号青铜神树的三维数字建模与静力学分析

结构稳定性是评估文物安全的重要方面。三星堆二号坑出土1号青铜树体量庞大、结构复杂,且存在腐蚀、裂纹等危险因素,为了充分记录、评估其保存状况,本研究在原始几何形状和内部构造的基础上,利用三维数字建模技术,建立其几何模型和数值模型,并估算出青铜神树的质量分布和质心位置等无法实地测量的数据,并使用有限元方法,从应力和位移的角度分析青铜树的静置状态下的安全性。经过有限元模拟和材料力学简化计算,发现龙身和树干连接处、树枝根部应力较大,是易受损区域。     

A Multi-Mode Method for Estimation of Floor Response Spectra

A new simplified procedure for estimation of floor response spectra (FRS) is proposed. This methodology enriches the most common procedures using nonlinear response-history analysis to predict FRS by including a direct multi-mode technique to estimate FRS. A novel feature of the procedure is that the coupling effect is considered to establish equivalent modal systems and the FRS are developed by incorporating capacity spectrum method in conjunction with ductility-based FRS for each modal system. Both the proposed method and the traditional method are applied to three steel moment frame structures, and a reasonable accuracy is demonstrated.     

Seismic Evaluation of Tall Buildings Using a Simplified but Accurate Analysis Procedure

A simplified analysis procedure for evaluating the nonlinear seismic responses of tall reinforced concrete (RC) buildings is examined in this study. It is called the Uncoupled Modal Response History Analysis (UMRHA) procedure. It can be viewed as an extended version of the classical modal analysis procedure, where the nonlinear response of each vibration mode is first computed, and they are later on combined into the total response of the structure. The procedure requires the knowledge of the modal hysteretic behavior, which can be obtained from a cyclic modal pushover analysis. The responses of four tall buildings in Bangkok to distant large earthquakes are computed by this procedure and compared with those obtained from the Nonlinear Response History Analysis (NLRHA) procedure. These four buildings have different heights—varying from 20 to 44 stories, different configurations of floor plan, and different arrangement of RC walls. The comparison shows that the UMRHA procedure is able to accurately compute the story shears and story overturning moments, floor accelerations, and inter-story drifts of all these tall buildings. The required computational effort is also extremely low compared to that of the NLRHA procedure. Moreover, since the UMRHA procedure computes the response of each individual vibration mode, it provides more understanding and insight into the complex nonlinear seismic responses of these tall buildings.     

Scalar Structure-Specific Ground Motion Intensity Measures for Assessing the Seismic Performance of Structures: A Review

The assessment of the seismic performance depends on the choice of the earthquake Intensity Measure (IM). During the past years many IMs, which take into account not only earthquake characteristics but also structural information, have been proposed. However, no consensus on which IM is the best predictor of the seismic response exists. Along these lines, the objective of this paper is to present the various developed scalar structure-specific seismic IMs and the problems associated with their use in practice, so that the engineer may become familiar with them and their implications in the context of Performance-Based Earthquake Engineering.     

明代石拱桥永昌桥的加固修缮技术研究

为明晰明代石拱桥的结构性能,并提出适宜的加固修缮方法,以典型的明代石拱桥永昌桥为例进行研究。首先对其进行精确测绘,获得其准确可靠的几何信息;然后对其建筑形制、构造工艺及残损状况进行研究,为结构性能分析提供依据;接着利用ANSYS软件建立永昌桥主体结构的有限元模型,进行包括荷载影响分析、重要度分析和裂缝分析的结构性能研究;最后基于现状分析和结构性能研究,通过对比拱背套钢筋混凝土拱加固法和拱背粘贴碳纤维布加固法对石拱桥的结构性能的影响,提出了明代石拱桥永昌桥的加固修缮方法。研究成果可为同类型石拱桥的加固修缮提供参考。     

试论《助字辨略》的成就与不足

清人刘淇所撰的《助字辨略》．是我国历史上第一部具有完整体例的虚词专著。全书共收虚词四百七十六个,分为三十类,并按四声对所收虚词分卷编次,依韵排列,同时类聚条析,讲解精当,对其后的虚词著作产生了深远的影响。但作者毕竟处于清学初起之时,那时虚词专著还处于开创阶段,这就注定《助字辨略》难免有一些缺陷和不足之处。     

Comparison of the Spectral Representation Method to Simulate Spatially Variable Ground Motions

The spectral representation method (SRM) is widely used when simulating spatially variable ground motions. It has mainly two formulas, i.e., the random amplitudes and the random phases formulas. There exist three methods for decomposing the cross spectral density matrix: Cholesky decomposition, eigen decomposition, and root decomposition. Therefore, there are six forms with respect to the different combinations of the simulation formulas and the decomposition methods. To provide researchers and engineers with the guidance on choosing simulation method, the six forms are systematically investigated from five aspects: the power intensity, response spectra, and stochastic error of auto/cross spectral density, Fourier spectra, and difference indexes for Fourier amplitudes and phases. Finally, we give the following advice: the characteristics of the ground motions simulated by the random amplitudes formula are independent of the decomposition method, while the characteristics of the ground motions simulated by random phases formula are dependent of the decomposition method. Furthermore, the root decomposition is strongly recommended when utilizing the random phases formula.     

Impact of Modification on Ground Motion Characteristics and Geotechnical Seismic Analyses for a California Site

The impact of different modification techniques on ground motion characteristics and results of seismic geotechnical analyses is investigated for a site in California. Twenty-eight motions were selected and scaled and also modified using both time domain (TD) and frequency domain (FD) techniques. PGV and PGD of the TD-modified motions are found to be larger than their FD-modified counterparts, but slightly less than the scaled ground motion characteristics. Cyclic stress ratios and amplification factors are similar for all sets of motions. Newmark-type slope displacements caused by the scaled and modified ground motions are similar (within 25%) for a variety of sliding masses.     

如何提高民办高校中学生的道德水平

民办高校发展是在无前人经验的基础上发展起来的,道德养成教育存在一定的问题与隐患。本文浅谈民办高校校园文化建设与道德养成教育相统一,有利于更好发挥校园文化建设的育人载体作用。