Unified analytical solution for deep circular tunnel with consideration of seepage pressure,grouting and lining

Journal of Central South University - A new unified analytical solution is presented for predicting the range of plastic zone and stress distributions around a deep circular tunnel in a homogeneous...     

地铁车站供配电与照明系统节能分析与节能措施的研究

通过对合肥市地铁车站供配电与照明系统进行分析和现场测试,综合分析了功率密度值、照度值及配电端的电能质量等能耗影响因素,评价供配电与照明系统的相关节能指标并提出了实用可行的节能措施,为地铁车站设计和节能管理提供了参考依据。     

Synthesis,characterization and thermal stability of CeO<Subscript>2</Subscript> stabilized ZrO<Subscript>2</Subscript> ultra fine nanoparticles via a sol-gel route

CeO₂ stabilized ZrO₂ ultra fine nanoparticles were successfully synthesized via a simple and effective sol-gel synthetic approach by using zirconylchloride octahydrate, cerium nitrate hexahydrate, and citric acid as starting materials. A series of techniques, including X-ray diffraction (XRD), thermogravimetry (TG), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and N₂-sorption analysis, were used to characterize the structure and morphology of the as-prepared samples. XRD studies indicate that the as-synthesized sample is of well crystallized tetragonal phase of CeO₂ stabilized ZrO₂ with high purity. TEM images show that the as-synthesized sample is composed of a large number of fine dispersive nanoparticles with an average size about 10 nm. The as-synthesized tetragonal CeO₂ stabilized ZrO₂ sample was heated at different temperatures in order to evaluate its thermal stability. The exprimental results reveal that the as-synthesized tetragonal CeO₂ stabilized ZrO₂ sample exhibits excellent stability without the occurrence of phase transformation.     

内陆干旱区实施最严格水资源管理的关键技术研究——以新疆呼图壁河流域为典型示范区

以最严格水资源管理理念为前提,从最严格水资源管理下的区域水资源综合模拟、水资源管理分配,以及典型研究区流域水资源监测框架核心技术及考核指标的评价体系这4个方面,研究内陆干旱区实施最严格水资源管理的关键技术,且以天山北坡中段呼图壁河流域为典型示范区,揭示流域内水资源的供需规律,建立适应内陆干旱区的最严格水资源管理制度,为实现区域水资源的可持续利用以及支撑区域经济社会的可持续发展提供科学依据和决策建议,为干旱区贯彻和落实最严格水资源管理制度提供科技支撑。     

U型65Mn钢板限位器扭转性能研究

通过对U型65Mn钢板限位器的扭转性能研究,推导其弹性扭转刚度及屈服荷载的理论计算公式,给出公式的适用范围.设计制作平直段长度L、宽度b、及钢板厚度t不同的40种限位器,进行静力加载试验.结果表明,限位器扭转位移主要由圆弧段扭转引起,钢板厚度t对限位器扭转刚度影响最大,增加板厚能够有效地增大刚度;板宽与刚度K近似呈一次正比关系;平直段长度越大,限位器扭转刚度越小.利用实验数据对理论公式进行修正,得到公式的修正系数.修正后的理论公式与实验数据吻合较好.     

Improved Computational Model of Grid Cells Based on Column Structure

To simulate the firing pattern of biological grid cells, this paper presents an improved computational model of grid cells based on column structure. In this model, the displacement along different directions is processed by modulus operation, and the obtained remainder is associated with firing rate of grid cell. Compared with the original model, the improved parts include that: the base of modulus operation is changed, and the firing rate in firing field is encoded by Gaussian-like function. Simulation validates that the firing pattern generated by the improved computational model is more consistent with biological characteristic than original model. Besides, the firing pattern is badly influenced by the cumulative positioning error, but the computational model can also generate the regularly hexagonal firing pattern when the real-time positioning results are modified.     

一类变时间分数阶扩散方程的Chebyshev小波数值法

运用第二类Chebyshev小波函数拟合的方法,求解一类变时间分数阶扩散方程.通过推导得出第二类Chebyshev小波的变阶微分算子矩阵,进而利用算子矩阵将方程转化为一组线性方程组,再利用最小二乘的方法求得方程组的解,进而得到原方程的数值解.并给出数值算例验证了本方法的有效性.     

长江流域2019年水旱灾害防御工作综述

2019年,在水利部党组的正确领导下,在流域各省(直辖市)的有力配合下,水利部长江水利委员会围绕新时期水利改革发展总基调和治江工作新定位,着力加强"补短板、强监管、夯基础、防风险",突出加强水工程调度运行监管,突出补齐综合调度信息化建设短板,全力做好流域水旱灾害防御工作,有效应对了2019年长江1号洪水和长江上游及汉江秋季洪水,取得了长江水旱灾害防御工作全面胜利。     

高分2号图像业务化大气校正查找表的设计与实现

为实现高分2号图像(GF2)业务化大气校正,利用矢量6S模型(6SV)将辐射传输散射与吸收进行分离计算,其中散射部分采用涵盖各种大气模式、气溶胶类型、成像几何等条件下的大气校正查找表(look-up tables,LUTs)表示,大气吸收部分采用6SV拟合计算的6种大气模式下大气透过率的经验公式表示,这种处理有效简化了查找表大小.在内存4 GB、主频3.10 GHz条件下,通过比较基于本查找表方法和基于FLAASH大气校正软件对北京地区一景GF2数据处理.结果表明:以6SV模型直接大气校正法结果作为真值,两者的绝对误差分别为0.8%和2.6%,处理时间分别为77 s和240 s,该大气校正查找表在处理精度和效率更加适合业务化大气校正.     

抗差自适应Kalman滤波及其在GNSS导航中的应用

针对Kalman滤波易受粗差影响而导致结果失真的问题,提出一种抗差自适应Kalman滤波方法,该方法结合自适应滤波与抗差Kalman滤波的优点,同时设计自适应因子和抗差因子,采用改进的两段Huber函数与2~3倍的观测噪声中误差来充当抗差因子与粗差判别标准。并对Kalman滤波和抗差自适应滤波(Adaptive Robust Kalman Filtering,ARKF)结果进行比较。车载实验结果表明,ARKF可以有效抵制观测异常对状态估值的影响,同时在系统先验信息不能精确给出的情况下,显著改善了滤波估值的稳定性和可用性。