利用微量元素示踪青铜器矿料来源的实验研究

通过仿古范铸实验和微量元素分析研究,可以初步得出利用微量元素示踪青铜器产地及矿料来源或探索古代矿冶产品输出路线是可行的,但要走新的技术路线的看法。     

现代博物馆管理模式探析

公益性文化事业管理模式的创新是当前文化体制改革的重要内容。博物馆作为公益性文化事业的重要组成部分,一直缺乏有效的管理模式,造成社会文化资源、经济资源巨大的浪费。本文以国外非营利组织和博物馆管理模式为借鉴,结合我国现状,提出了中国社会主义市场经济体制下现代博物馆管理模式的构想。     

基于时变参数模型的中国房地产投资研究

房地产投资能够直接带动国民经济增长,但发展过快也会给经济带来负效应,协调好房地产投资与国民经济发展的关系尤为重要。本文首先综述国内外相关研究成果,发现现有定量研究无法真实反映房地产业本身结构的变化;其次,建立时变参数模型,对房地产投资与国民经济发展之间的关系进行了实证研究;最后得出研究结论和政策建议。本文的研究结论:一是房地产投资对GDP拉动作用显著;二是房地产投资受GDP、国内银行贷款以及利率的影响各不相同。与现有研究文献相比较,本文在研究视角和方法上均有-定的突破。     

Rapid Diagnosis of Crack Patterns of Masonry Buildings Subjected to Landslide-Induced Settlements by Using the Load Path Method

One of the main difficulties, when dealing with landslide structural vulnerability, is the diagnosis of the causes of the crack pattern. This is also due to the excessive complexity of models based on classical structural mechanics that makes them inappropriate especially when there is the necessity to perform a rapid vulnerability assessment at the territorial scale. This is why in this article a new approach for the rapid diagnosis of crack patterns of masonry buildings subjected to landslide-induced settlements is proposed. This approach is based on the Load Path Method, recently applied to the interpretation of the behavior of masonry buildings subjected to landslide-induced settlements.     

Hysteretic Model for Flexure-shear Critical Reinforced Concrete Columns

A model for predicting the cyclic lateral load-deformation response of flexure-shear critical reinforced concrete (RC) columns subjected to combined axial load and cyclic shear is proposed. Strength deterioration in the primary curve due to the effect of shear after yielding is considered by a modification coefficient. Rules for unloading and reloading branches of the hysteretic curve are obtained from regression analysis of test results. Unloading stiffness is fitted as a function of displacement ductility and secant stiffness of the point with maximum displacement in the primary curve. Pinching is simulated by changing the slope of reloading branch. Path-based cyclic strength deterioration is incorporated in the proposed model. In the expression of cyclic strength deterioration, the effects of aspect ratio and axial-load ratio are considered. Comparison between the predicted cyclic response and experimental results indicates that the proposed model can predict the observed hysteretic response of flexure-shear critical RC columns well.     

乡村旅游对农户农林业生产和外出务工影响研究——基于陕西22个旅游扶贫村农户调查数据

利用课题组2017年6-8月在陕西安康、商洛、汉中、宝鸡4市9县22个旅游扶贫村收集的841个农户调查数据，采用双重选择模型（DSM）等分析了农户参与旅游对家庭农林业劳动时间、外出务工时间的影响。研究发现，参与旅游有助于增加调查地的农户收入，旅游兼营型农户收入更高。在全样本中，参与旅游对农户农林业生产时间具有显著负向作用，但在参与了旅游的农户样本中，农户参与旅游一些特征或形式，如土特产销售，对农林业生产则有显著正向作用；在多个模型中，农户从事旅游对家庭外出务工活动具有显著的负向作用。提出了延长农业产业链、发展“旅游+农业”、促进农村一二三产业融合，提高景区带村作用、完善旅游扶贫政策等对策建议。     

乾嘉常州诗派中的“洪亮吉范式”

乾嘉常州诗派除了诗歌风格上的趋同外,在伦理道德上亦有相似之处,他们大多忠、孝、友、悌皆备,道德、文章俱佳。常州诗人的忠梗、迂憨在洪亮吉身上体现得尤为集中,堪称范式。对其进行个案研究,既可促进对洪亮吉及其诗歌与诗学理论的探讨,亦可促进对常州诗派的思考,同时对透析乾嘉士子心态,洞悉乾嘉士风与世风亦有裨益。     

Evaluation of Side Boundary Effects on Dynamic Numerical Modeling for Centrifugal Model Tests

Four different boundary conditions consisting of fixed nodes, motion of roller only in the z or the x direction, and equivalent motion of two side boundaries were applied with a finite element code to simulate seismic behavior of two foundation conditions consisting of dry loose and dense sands. Comparing numerical results with physical model tests indicates that data obtained from the finite element code when considering soil nonlinearity with a sand model based on the tij concept have acceptable agreements with those from dynamic centrifuge tests regardless of the boundary conditions. The results from the boundary conditions of roller in the x direction and equivalent motion of two side boundaries agree well with the experimental data in wave peaks. The two side boundary conditions also keep the ground middle undisturbed and provide the results that are similar to those obtained from the wave amplification experimental data. For numerical simulations of centrifuge model tests, the side boundary condition with roller in the x direction is recommended because of low computation time and high simulation quality.     

Generation of Multiple Earthquake Accelerograms Compatible with Spectrum Via the Wavelet Packet Transform and Stochastic Neural Networks

The principal purpose of this article is to present a novel methodology based on wavelet packet transform techniques and stochastic neural networks to generate more artificial earthquake accelerograms from available data, which are compatible with specified response spectra or the design spectra. The proposed method uses the decomposing capabilities of wavelet packet transform on earthquake accelerograms, and the learning abilities of stochastic neural network to expand the knowledge of the inverse mapping from response spectrum to coefficients of wavelet packet transform of earthquake accelerogram. This methodology results in a stochastic ensemble of wavelet packet transform coefficients of earthquake accelerograms and, they are used to the generate accelerograms applying the inverse wavelet packet transform. Finally, an interpretive example is presented which uses an ensemble of recorded accelerograms to train and test the neural network, aiming at the demonstration of the method effectiveness.     

Probabilistic Characteristics of Seismic Ductility Demand of SDOF Systems with Bouc-Wen Hysteretic Behavior

This study investigates probabilistic characteristics of the peak ductility demand of inelastic single-degree-of-freedom systems. The hysteretic behavior of structural systems is represented by the Bouc-Wen model, which takes various hysteretic curves with degradation and pinching behavior into account, and a prediction equation of the peak ductility demand is developed. The application of the developed equation in reliability analysis of structures subject to earthquake loading is illustrated. The results indicate that the effects due to degradation and pinching behavior on the peak ductility demand as well as the reliability of structures can be significant, especially for stiff structures.