采用软交换技术实现MSC冗灾备份

本文通过对软交换技术架构、组网方式、话务信令路由等方面的分析,探讨如何采用软交换技术对传统移动交换端局进行冗灾备份.     

RNG κ-ε湍流模型在三维弯曲河流中的应用

本文采用非正交曲线坐标下的三维RNGκ-ε双方程湍流数学模型,该模型在水平方向采用非正交曲线坐标,在垂直方向采用等分网格的全坐标变换,采用由二维深度平均方程演化而来的2-D泊松方程计算三维自由水面,应用SIMPLEC程式求解方程.通过两个180°弯曲渠道和天然河流Fall River部分河段对本文的数学模型进行验证,给出水位、流速及二次流的分布图等.对比分析,本模型的计算结果和实测值吻合很好,表明采用2-D泊松方程法计算三维自由水面是可行的,RNG κ-ε湍流数学模型可以应用到天然河道的计算中去.     

花岗岩差异性风化层的大地电磁法EH-4勘察效果研究

花岗岩地区的高速公路隧道开挖过程中,因岩体特有的差异性风化导致全、强风化层向下深切,这些岩体完整性差,裂隙发育、富水性强,存在施工安全隐患,深切的全、强风化层底界面起伏范围大且无规律,勘察难度较大。结合隧道工程勘察案例总结大地电磁法EH-4在探测花岗岩差异性风化形成的全、强风化层下切界面的效果,探索了利用物探解释划分围岩级别的可行性。最终经过工程验证,取得了较好的效果,在相似地质条件地区,值得推广。     

Adaptive neural network output feedback control of stochastic nonlinear systems with dynamical uncertainties

In this paper, a robust adaptive neural network (NN) backstepping output feedback control approach is proposed for a class of uncertain stochastic nonlinear systems with unknown nonlinear functions, unmodeled dynamics, dynamical uncertainties and without requiring the measurements of the states. The NNs are used to approximate the unknown nonlinear functions, and a filter observer is designed for estimating the unmeasured states. To solve the problem of the dynamical uncertainties, the changing supply function is incorporated into the backstepping recursive design technique, and a new robust adaptive NN output feedback control approach is constructed. It is mathematically proved that the proposed control approach can guarantee that all the signals of the resulting closed-loop system are semi-globally uniformly ultimately bounded in probability, and the observer errors and the output of the system converge to a small neighborhood of the origin by choosing design parameters appropriately. The simulation example and comparison results further justify the effectiveness of the proposed approach.     

Study on the estimation of near-surface air temperature from MODIS data by statistical methods

Spatially distributed air temperature is desired for various scientific studies, including climatalogical, hydrological, agricultural, environmental and ecological studies. In this study, empirical models with regard to land cover and spatial scale were introduced and compared to estimate air temperature from satellite-derived land surface temperature and other environmental parameters. Aqua MODIS (Moderate Resolution Imaging Spectroradiometer) data and meteorological data obtained throughout 2005 in the Yangtze River Delta were adopted to develop statistical algorithms of air temperature. Four empirical regression models with different forms and different independent variables resulted in errors ranging from 2.20°C to 2.34°C. Considering the different relationships between air temperature and land surface temperature for different land types, these four models were evaluated and the most proper equation for each land-cover type was determined. The model containing these selected equations gave a slightly improved mean absolute error (MAE) of 2.18°C. Then the spatial scale effect of this empirical model was analysed with observed air temperature and spatially averaged land surface characteristics. The result shows that the estimation error of air temperature tends to be lower as spatial window size increases, suggesting that the model performances are improved by spatially averaging land surface characteristics. Comprehensively considering the accuracy and computational demand, 5 × 5 pixel size is the most favourable window size for estimating air temperature. The validation of the empirical model at 5 × 5 pixel size shows that it achieves an MAE of 1.98°C and an R ² of 0.9215. This satisfactory result indicates that this approach is proper for estimating air temperature, and spatial window size is an important factor that should be considered when calculating air temperature. It is expected that better accuracy will be achieved if the different weights of pixels at different distances can be set according to high-density micro-meteorological data.     

框-剪结构高层综合楼结构设计及优化措施分析探讨

现代高层建筑正朝着高度更高、跨度大、结构更复杂的方向发展。本文结合具体工程实例,从概念设计、整体结构计算、局部构造设计等方面详细分析阐述了带转换层的结构较为复杂的框-剪结构高层综合楼结构设计及优化措施,并对设计效果进行了分析和总结,供同行借鉴参考。     

压裂液返排率的理论计算

压裂液返排率是评价压裂效果的一个重要参数,而返排率的求取往往是压裂施工结束后现场液体收集得到,缺乏相关理论模型进行预测。为了丰富压裂设计及评价理论体系,从压裂液返排机理出发,考虑裂缝闭合前后压裂液返排不同的返排过程,根据物质平衡原理、岩石力学和渗流力学,建立了返排率计算的数学模型,分析了地层渗透率、孔隙度、裂缝导流能力、破胶压裂液黏度对返排率的影响,计算结果表明,地层孔隙度对压裂液返排率影响较小,破胶压裂液黏度、裂缝导流能力、地层渗透率对返排率影响较大,提高破胶压裂液黏度和裂缝导流能力对于返排率的提高有重要的意义。     

全蒸发技术在铀同位素丰度测量上的应用

采用全蒸发技术、离子流强度积分的方式 ,用多接收器热表面电离质谱计测量铀同位素丰度。全蒸发技术可克服质量分馏效应带来的测量误差 ,而直接实现准确测量。开发了用于全蒸发技术的测量软件 ,对影响测量结果的因素 ,诸如分析用样量、信号损失与试样残留等进行了研究。最后得出在铀同位素丰度比为 0 1～ 10的范围内 ,95 %的置信水平下 ,该方法的相对扩展不确定度为0 10 %     

深层裂缝性复杂岩性气藏压裂技术研究

新疆准噶尔盆地WB气藏储层深度2 200～4 500m,储层岩石中的火山岩含量达45%,天然微裂缝发育,储层表现为强水敏,压裂施工难度大.文章首先对WB气藏前期压裂施工资料进行了综合分析,明确了前期压裂改造存在的主要问题;结合该气藏的储层地质特征,从储层污染、压裂液伤害、压裂施工和压后排液等方面系统研究了影响该区压裂效果的关键因素和技术对策.提出了应用综合控高技术来防止缝高过度延伸,采用支撑剂段塞、优化施工参数等实现降滤失和防治多裂缝,并通过支撑剂嵌入实验和压裂液性能评价优选了适合该地层的支撑剂和压裂液体系.研究思路与技术认识对于WB气藏及类似低渗气藏的压裂改造具有一定指导意义.     

三面内抽芯盒盖注射模设计

介绍三面内抽芯盒盖注射模的模具结构及工艺原理，并指出了该模具的设计要点。