THE REIMPROVEMENT FOR IMPULSE OF G. I. TAYLOR THEORY OF PLASTIC DEFORMATION IN IMPACT OF CYL1NDICAL PROJECTILES

In this paper the reimprovement for G. I. Taylor theory of plastic deformation in impact of cylindical projectiles is done. The impulse in the reimproved theory is G. I. Taylor' s 1/2, and 3/4 of G. I. Taylor' s improved theory. The analytical solution of the reimproved theory shows that it gives better agreement with exprimental results than those of the original Taylor' s theory and, the improved theory.     

Precipitation forecasting by large-scale climate indices and machine learning techniques

Global warming is one of the most complicated challenges of our time causing considerable tension on our societies and on the environment. The impacts of global warming are felt unprecedentedly in a wide variety of ways from shifting weather patterns that threatens food production, to rising sea levels that deteriorates the risk of catastrophic flooding. Among all aspects related to global warming, there is a growing concern on water resource management. This field is targeted at preventing future water crisis threatening human beings. The very first stage in such management is to recognize the prospective climate parameters influencing the future water resource conditions. Numerous prediction models, methods and tools, in this case, have been developed and applied so far. In line with trend, the current study intends to compare three optimization algorithms on the platform of a multilayer perceptron (MLP) network to explore any meaningful connection between large-scale climate indices (LSCIs) and precipitation in the capital of Iran, a country which is located in an arid and semi-arid region and suffers from severe water scarcity caused by mismanagement over years and intensified by global warming. This situation has propelled a great deal of population to immigrate towards more developed cities within the country especially towards Tehran. Therefore, the current and future environmental conditions of this city especially its water supply conditions are of great importance. To tackle this complication an outlook for the future precipitation should be provided and appropriate forecasting trajectories compatible with this region's characteristics should be developed. To this end, the present study investigates three training methods namely backpropagation (BP), genetic algorithms (GAs), and particle swarm optimization (PSO) algorithms on a MLP platform. Two frameworks distinguished by their input compositions are denoted in this study: Concurrent Model Framework (CMF) and Integrated Model Framework (IMF). Through these two frameworks, 13 cases are generated: 12 cases within CMF, each of which contains all selected LSCIs in the same lead-times, and one case within IMF that is constituted from the combination of the most correlated LSCIs with Tehran precipitation in each lead-time. Following the evaluation of all model performances through related statistical tests, Taylor diagram is implemented to make comparison among the final selected models in all three optimization algorithms, the best of which is found to be MLP-PSO in IMF.     

新疆玛纳斯河流域玉米田蒸散量的估算研究

根据新疆乌兰乌苏农试站１９８７－１９８８年的试验资料,选用Ｐｒｉｅｓｔｌｅｙ和Ｔａｙｌｏｒ的农田蒸散力,作物生物学特性函数和农田土壤水分有效性函数,应用数理统计方法建立了新疆玛纳斯河流域玉米田蒸散量估算模型。该模型只需常规气象资料和农业气象资料,计算简便,具有较高的精度,便于在干旱区推广使用。     

捷联惯导系统姿态算法的仿真模拟

在捷联惯性导航系统中,姿态矩阵可用四元数来表示,从而常常需要计算四元数矩阵微分方程的问题.4阶龙格-库塔法和3阶泰勒展开递推式法对捷联惯导系统的四元数姿态矩阵作仿真,结果表明：在短步长条件,3阶泰勒展开递推式法比4阶龙格-库塔法更有效.本文为改进捷联惯导系统算法提供了参考依据.     

新疆2种苔类植物挥发油鉴定1）

采用水蒸气蒸馏法对新疆地钱和钝叶光萼苔等2种苔类植物挥发油进行提取,并用气相色谱—质谱联用技术进行分离鉴定;采用峰面积归一化法确定各成分的质量分数。结果表明：地钱挥发油中共分离出24种成分,确认了其中的22种成分;钝叶光萼苔挥发油中共分离出25种成分,确认了其中的19种成分,两者主要成分为烯萜类和醇类化合物。     

基于DSGE模型的利率传导机制研究

动态随机一般均衡模型对中国的经济数据拟合较好,可用来分析中国的经济问题;利率作为中国货币政策的中介目标是适宜的,泰勒规则可以用来指导中国的货币政策实践;利率冲击通过影响资本投资价值进而投资而对产出产生影响,消费的传导作用相对较小。     

Tissue responses to fractional transient heating with sinusoidal heat flux condition on skin surface

A fractional model of Bioheat equation for describing quantitatively the thermal responses of skin tissue under sinusoidal heat flux conditions on skin surface is given. Laplace transform technique is used to obtain the solution in a closed form. The resulting formulation is applied to one‐dimensional application to investigate the temperature distribution in skin with instantaneous surface heating for different cases. According to the numerical results and its graphs, conclusion about the fractional bioheat transfer equation has been constructed. Sensitivity analysis is performed to explore the thermal effects of various control parameters on tissue temperature. The comparisons are made with the results obtained in the case of the absence of time‐fractional order. © 2016 Japanese Society of Animal Science     

水声传感器网络节点自定位的遗传算法优化研究

水声传感器网络节点自定位技术是传感器网络在海洋环境监测应用的基础。针对质心算法在随机分布中定位精度较低的缺点,采用信标节点与未知节点之间的距离作为约束,并对该约束采用泰勒级数方式展开;由此建立相应的数学模型,通过遗传算法对该模型进行优化;此外,根据信号传播特点,采用的是等高线传输模型。仿真结果表明,该方法能够实现水声传感器网络未知节点的有效定位。     

沟槽壁面对泰勒涡流稳定性影响的数值模拟

利用CFD数值模拟方法对光滑壁面与沟槽数量为18的2种同心圆柱模型内的泰勒-库艾特流动进行计算,在对比光壁模型的PIV试验与CFD数值计算结果后,发现两者吻合良好,验证了文中采用数值计算方法的准确性;针对泰勒涡流流态,定量分析了光壁模型R-Z平面上径向速度以及轴向速度的周期波动性,讨论了环隙中不同径向位置的径向以及轴向速度分布规律,获得了泰勒涡胞尺寸随着Re数增大而减小的变化规律;在相同的Re数下,沟槽数量为18的模型内也出现了泰勒涡流,通过比较2种不同结构模型内流场以及涡量场,发现沟槽的存在显著改变了流场分布,增大了环隙内涡量的大小及泰勒涡胞的尺寸,环隙中部指向外圆柱方向的径向速度也较光壁模型增大了20%,同时,计算获得R-θ平面内沟槽区域的流场分布表明该区域存在着明显的旋涡运动.     

Methods of Rock Crack Density Determination and Their Application

By the methods of micro damage theory, the relations of rock mass parameters and rock parameters in experiments were obtained; it is considered that to make the micro damage theory for determining the rock parameters possible only in condition that the crack density parameters are obtained reasonably. The methods to determine rock mass crack density have been set up through the intactness index of rock mass and elastic wave equation as well as the geological investigating statistical method, The differences of rock crack density given by these three methods were discussed; based on the statistical data, the Taylor method and generalized self consistent method and the Taylor medium method were compared in respect of the influence of crack interaction and the adaptability to the rock parameters . The results show that the reasonable results can be obtained by determining rock crack density from intactness index of rock mass and rock mass parameters by the Taylor medium method.