MnO的电子结构

采用杂化密度泛函方法对MnO的电子结构进行了研究。结果表明，杂化密度泛函方法明显改进了理论与实验的符合。MnO为电荷转移绝缘体，采用离子模型能较好地解释其电子结构。     

PHONON-EXCITON MECHANISM IN YBa2Cu3O7-δ SYSTEM

In this paper, based on the phonon-exciton mechanism, the superconductivity of yttrium barium copper oxide (YBCO) system is explained. The transition temperature (Tc) 's formula is derived by the extended BCS-Eliashberg theory, i.e. phonon-exciton mechanism and McMillan's energy gap function, and the Tc's expressions isreduced by using the Einstein spectrum. Last, the calculating method of element metal effective phonon spectrum is used to the high Tc cuprate YBCO system by using a crystal average atom approximation model. The theoretical analysis and calculational results show that the superconductivity of high Tc YBCO system maybe described by phonon-exciton model.     

Parametric study of wheel transitions at railway crossings

Vehicle–track interaction at railway crossings is complex due to the discontinuity of the crossings. In this study, the effect of the local crossing geometry, the track alignment, and the wheel profiles on the wheel transition behaviour is investigated using the multi-body system software package VI-Rail. The transition behaviour is evaluated based on the location of the transition point along the crossing (and the location of impact), the contact pressure and the energy dissipation during the wheel–rail contact. A detailed parametric study of the crossing geometry has been performed, through which the most effective parameters for defining the crossing geometry are identified. These parameters are the cross-sectional shape of the nose rail, which can be tuned by one variable, and the vertical distance between the top of the wing rail and the nose rail. Additionally, a parametric study on the interaction influence of the crossing geometry, the track alignment and the wheel profile is performed using the design of experiments method with a two-level full factorial design. The longitudinal height profile of the crossing and the wheel profile are the most significant factors.     

不同型式路桥过渡段动力特性对比分析

针对路桥过渡段的动力响应问题,通过建立轨道路基动力分析模型,结合商业软件FLAC对某客运专线加筋土路桥过渡段、级配碎石路桥过渡段进行了仿真分析,将2种过渡段的计算结果进行对比分析、并将加筋土路桥过渡段的计算结果与实测数据进行比较,结果表明该模型能反映系统振动特性,并从理论上论证了加筋土路桥过渡段比级配碎石路桥过渡更能阻止动应力与振动加速度在路基中的传播,能使路基受到更小的动荷载影响.     

Railway ground vibrations induced by wheel and rail singular defects

Railway local irregularities are a growing source of ground-borne vibration and can cause negative environmental impacts, particularly in urban areas. Therefore, this paper analyses the effect of railway track singular defects (discontinuities) on ground vibration generation and propagation. A vehicle/track/soil numerical railway model is presented, capable of accurately predicting vibration levels. The prediction model is composed of a multibody vehicle model, a flexible track model and a finite/infinite element soil model. Firstly, analysis is undertaken to assess the ability of wheel/rail contact models to accurately simulate the force generation at the wheel/rail contact, in the presence of a singular defect. It is found that, although linear contact models are sufficient for modelling ground vibration on smooth tracks, when singular defects are present higher accuracy wheel/rail models are required. Furthermore, it is found that the variation in wheel/rail force during the singular defect contact depends on the track flexibility, and thus requires a fully coupled vehicle/track/foundation model. Next, a parametric study of ground vibrations generated by singular rail and wheel defects is undertaken. Six shapes of discontinuity are modelled, representing various defect types such as transition zones, switches, crossings, rail joints and wheel flats. The vehicle is modelled as an AM96 train set and it is found that ground vibration levels are highly sensitive to defect height, length and shape.     

立交匝道中线及边桩的坐标放样

本文推导了立交匝道等道路交通中线和边桩在城市坐标系中的坐标计算公式 ,并介绍了实现整个线路实现连续统一计算的程序设计思路。采用本文所提供的计算方法 ,采用全站仪、GPS等仪器进行立交匝道放样极为方便     

船舶结构用铝—钛—钢复合过渡接头疲劳性能研究

铝－钛－钢爆炸复合板作为新型舰船结构铝合金，钢之间连接过渡接头取代传统的铆接连接具有优越的连接性能和施工工艺。本研究模拟实际应用条件，测定了其焊接前后在固定应力水平下的弯曲疲劳寿命和弯曲疲劳Ｓ－Ｎ曲线，并运用计算机得到Ｓ－Ｎ曲线的回归方程，为复合过渡接头疲劳寿命的预测和最大应力的控制等提供了依据。     

平台罗经惯导工作状态的转换研究

以由二自由度陀螺仪及脉冲积分摆式加速率计构成的平台较经系统的研究对象，讨论了平台罗经向惯导过渡的必要性及可行性，提出了快速平稳过渡方案，最终给出了计算机仿真结果。     

秦沈客运专线东部软土路基的结构特点及施工技术

本文以秦沈客运专线 A14标为例介绍了东部软土路基的结构特点及施工体会 ,对软基处理、基床表层的填筑、过渡段的施工等关键工序的施工工艺进行了总结 ,尤其对沉降观测的特点及对软土路基施工控制的作用进行了详细的探讨。     

利用点到中线的垂距计算方法选择最佳既有曲线要素

利用文献[1]给出的中点到中线垂距计算公式及程序，提出一种新的优化计算方法，能简便而圆满地解决既有曲线要素的选择问题，这一方法对于不同的目标函数，不同的线形、是否有控制条件等，计算过程基本一样，该法还很容易推广到选取第二线的曲线要素。