强迫布鲁塞尔振子相图的研究

针对强迫布鲁塞尔振子模型的Ｆａｒｅｙ序列与Ｍ．Ｓ．Ｓ序列进行了扩大区域的研究，表明单峰映中看成圆映象的近似，并建立了圆映象的相图，单峰映象的相图及符号动力学间的关系。     

Timing sequence changes of landscape plants in Shanghai Area,China

Based on published reports and direct observation, the common resources of landscape plant species in the Shanghai area were identified and studied in terms of the landscape characteristics of timing sequence changes over a one year time period. The results showed that there were 199 common landscape plant species in Shanghai, distributed in 67 families and 129 genera. These plants were categorized by three ornamental characteristics: flowers, foliage and fruits. The species were thus further analyzed according to the time periods which these characteristics were present. The results showed that flower ornamental distributed throughout the year, particularly from April to June, and plant species with colorful foliage could be seen every month, and particularly in November and December. On the other hand, few plant species with fruit ornamentals were observed in Shanghai area. The diversity of landscape timing sequence changes of the 199 plant species under examination was then analyzed by using the Shannon-Weiner and Simpson index formulas. The results showed that the higher diversity was observed in January, February and from August to October, while the lowest diversity was recorded from March to July and during November and December. The diversity of landscape characteristics of these plants was ranked according to foliage, flowers and fruit. Using this method, one park and one plant community were selected to evaluate the advantages and disadvantages of their time-changing plant landscape, with the goal of assessing the validity of the chosen ranking method. These results in the present study would be helpful to evaluate the plant landscape in a specified space and further enrich the diversity of plant and landscape by a target-oriented way.     

A mixed Bayesian network for two-dimensional decision modeling of departure time and mode choice

The modeling of travel decision making has been a popular topic in transportation planning. Previous studies focused on random-utility discrete choice models and machine learning methods. This paper proposes a new modeling approach that utilizes a mixed Bayesian network (BN) for travel decision inference. The authors use a predetermined BN structure and calculate priori and posterior probability distributions of the decision alternatives based on the observed explanatory variables. As a “utility-free” decision inference method, the BN model releases the linear structure in the utility function but assumes the traffic level of service variables follow multivariate Gaussian distribution conditional on the choice variable. A real-world case study is conducted by using the regional travel survey data for a two-dimensional decision modeling of both departure time choice and travel mode choice. The results indicate that a two-dimensional mixed BN provides better accuracy than decision tree models and nested logit models. In addition, one can derive continuous elasticity with respect to each continuous explanatory variable for sensitivity analysis. This new approach addresses a research gap in probabilistic travel decision making modeling as well as two-dimensional travel decision modeling.     

日本造船业的危机应对

接单策略偏于谨慎 2008年初时,日本各大船厂手持订单饱满,生产任务普遍排至2011年左右,而造船钢材价格却是一涨再涨,使得本来可以获利的订单转眼间变成赔本的生意,船厂的财务业绩因钢材上涨而面临巨大压力,接单越多可能最后亏损越多.     

基于标度扩展的AHP在飞机空战效能评估中的应用

阐述了标度扩展AHP法的基本原理和步骤,基于该方法对三种典型战斗机的空战效能进行评估,结果表明,采用标度扩展的AHP法进行效能评估,可以减少计算量,并能提高结果的可信度。     

丹东地区及港口船舶防污问题探讨

随着丹东地区经济的快速发展,丹东地区渔船、游船、货船的船舶数量也随着增加,而船舶污染也随之严重起来。报告了丹东港口船舶污染问题的现状,对船舶不正当排放的污染源及船舶污染的特点进行调查,最后对船舶污染的治理提出建议。     

Soil Body Deformation Caused by Construction of a Double-Line Shield Tunnel with Multiple Factors北大核心CSCD

Considering the influence of many factors (soil loss, frontal additional thrust, the friction force of the shield shell and the additional grouting force), a method for improving the uniform soil body movement model is pro-posed, and a mechanical calculation model is established to study the calculation method for soil body deformation caused by double-line parallel shield driving. Based on the Mindlin solutions of elastic mechanics, the theoretical solutions for soil body deformations caused by the last three factors are calculated; considering the uniform soil body movement model, the theoretical solutions for soil body deformations caused by soil loss are calculated, then the to-tal theoretical solutions for soil body deformations under multiple factors are obtained by means of superposition. The vertical surface settlement, vertical horizontal displacement, and vertical displacements of the soil body at different depths of Hangzhou Metro Line 1 are calculated to analyze the variation laws. Meanwhile the influential factors for horizontal displacement variation are studied. The research shows that with a change of depth, the settlement of the soil body changes within the scope of 10 to 13 m in the horizontal direction near where the maximum settlement occurs;the direction of the horizontal displacement of the soil body changes with a change of the positional relationship be-tween the calculation points and the tunnel; and with an increase of interval J for the two tunnels, the horizontal dis-placement of the soil body of a deep double-line tunnel decreases while the displacement near the surface changes slightly. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

A Study of Prevention Techniques for Tunnel Lining Defects北大核心CSCD

Defects of tunnel lining, such as inadequate thickness, voids, cracks, rock falling and water leakage etc., endanger the safety of railway tunnel operation. Based on the site construction, an analysis of the reasons for lining defects was conducted; technical measures against lining defects were proposed and tests were carried out at site. The results show that these measures are reliable and effective, and the purposes of prevention and treatment are re⁃ alized. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

浅谈箱梁顶板的横向计算分析

箱梁顶板的横向计算是箱梁横截面设计的重要组成部分。本文通过对某一斜腹板箱梁的横向计算,为桥梁工程设计提供一个参考。     

大断面浅埋偏压隧道CRD法施工工序研究

文章以良村隧道CRD法施工为工程背景,布设了变形监测点及内力测试元件,分析了CRD法施工隧道围岩变形情况及结构内力特征,并对CRD法施工隧道在不同开挖顺序下的开挖过程进行了数值模拟,分析比较了不同开挖顺序时的围岩位移、应力变化情况。结果表明:CRD法对各分部施工工序影响较大,且各分部对拱顶下沉的影响程度从大至小依次为1部、2部、3部和4部;隧道内侧围岩压力大于外侧,钢支撑内力均为压应力,且拱腰位置轴力大于其它部位。比较隧道开挖变形的差异以及结构的受力特点,结合数值分析结果,得出了山体外侧先开挖方案无论在围岩变形还是隧道结构受力方面相比于山体外侧后开挖都较小,安全系数相对较高。因此,合理的施工工序应该是先进行山体外侧开挖并施作初期支护,然后再在山体内侧开挖施工。