城市需水量模拟及不确定性分析方法研究

需水量预测是区域水资源合理配置和有效管理的基础。由于供需水量的不确定性,精准的需水量预测较有困难。通过建立径向基函数（RBF）与BP神经网络预测模型,以西北地区城市西安市需水量为例,将用水量驱动因子作为模型输入,利用1990-2009年20组年用水数据进行网络训练模拟,对2010-2012年3组年用水数据进行检验预测,采用不确定性评价指数和置信区间方法对两种模型及模拟结果进行比较分析。结果表明,RBF与BP模型预测期的均方根误差分别为0.08、0.26,不确定性评价指数分别为0.74、1.02且BP模型预测值的相对误差最大超过10%以上,而RBF模型预测值的相对误差均小于5%,说明RBF模型模拟效果好,具有预测精度高以及不确定性影响低的双重优势;在模拟结果基础上,引用置信区间分析了结果的可靠性,为分析城市需水预测的不确定性提供了依据。     

The Evaluation on Biological Properties of Carboxymethylchitosan and Carboxymethyl-chitin

Carboxymethyl-chitosan and carboxymethyl-chitin were prepared with the methods developed in our laboratory. The DS （degree of substitution） and DD （degree of deacetylation） of the carboxymethyl-chitosan were 103.14% and 97.18% respectively, while the DS of the carboxymethyl-chitin was 96.37%. Their effects on human fibroblasts, intradermal irritation test, in vitro and vivo degradability, and biocompatibility were evaluated. The results indicate that the polysaccharides at low concentrations can facilitate the growth of human fibroblasts and the carboxymethyl-chitosan at 100 μg mL^-1 is the most effective. The polysaccharides at higher concentrations, however, inhibit the growth of fibroblasts. The PII （Primary Irritation Index） values of CM-chitosan and CM-chitin are both 0.0, which shows that they have no irritation reaction. Both of the polysaccharides show good degradability and biocompatibility. Carboxymethyl-chitin degrades faster in vitro than carboxymethyl-chitosan. The latter, however, has no inflammatory reaction after being implanted in vivo for 7 d and shows better biocompatibility. This study may provide a scientific basis for the use of earboxymethyl-ehitosan and carboxymethyl-chitin as biomaterials.     

沪昆客专沙坡特大桥危岩落石形成机制及防治措施研究

沪昆高铁贵昆段沙坡特大桥线路左侧多处危岩落石对大桥构成一定威胁。本文在对区域地质环境和危岩体结构特征的调查的基础上,利用无人机航拍技术,查明了沙坡双线特大桥左侧山坡坡顶裂缝及围岩体的分布,研究了该处危岩落石体的形成的机制,并提出了采用梯形垛反压、清方、灌浆以及局部支挡的防治措施,取得了良好的经济效益,同时保障了沪昆客专安全、有序运营。     

基于遗传支持向量机的地下工程裂隙岩体注浆量预测

提出了地下工程裂隙岩体注浆量预测的遗传支持向量机方法,通过支持向量机对实际注浆数据样本进行学习,建立注浆量及其影响因素之间的非线性映射关系,基于这种关系实现注浆量的预测。模型建立过程中,考虑到支持向量机惩罚因子和核参数对预测精度的影响,以预测误差为适应度,采用遗传算法对最佳参数进行搜索。结果表明,本文方法计算快速,预测精度高,是一种注浆量预测的好方法。     

Rapid, sensitive detection of Vibrio anguillarum using loop-mediated isothermal amplification

Vibrio anguillarum is an important bacterial pathogen of aquatic organisms and a significant problem in aquatic farming. The rapid detection and identification of V. anguillarum, and other pathogens that infect marine organisms, is crucial to effective disease management. In this study, we developed a loop-mediated amplification (LAMP) assay to detect V. anguillarum in an hour in a single tube without the need for thermal cycling. Conserved regions of the metalloproteinase (empA) gene of V. anguillarum served as the targets for primer design. A fragment of the empA gene was amplified at 65°C in the presence of the primer mixture and Bst DNA polymerase. In the optimized LAMP assay, 6.7 pg of V. anguillarum DNA could be detected. Six strains of V. anguillarum and 17 strains of non-V. anguillarum bacteria were used in this study to evaluate the species specificity of the primers. The six V. anguillarum strains gave a positive result in the LAMP assay. This method was also validated in V. anguillarum-infected fish. This LAMP method is more sensitive than PCR in the detection of V. anguillarum and shows good species specificity. The LAMP assay is therefore an effective method for the quick detection of V. anguillarum both in the laboratory and in the field.     

高墩大跨度刚构桥抗震加固有限元分析

大跨刚构桥结构桥跨较长和受力复杂。为提高抗震性能,需要对加固前后的桥梁进行抗震性能研究。以某双肢薄壁型高墩大跨度刚构桥为背景,采用ANSYS程序APDL语言,对结构进行合理的参数选取、网格划分和边界约束,结合抗震等级和桥梁规范等有关规定,研究整体结构在地震作用下的变化规律。通过沿墩高方向获取节点的方法,确定在地震作用下,各节点的最大位移从下到上逐渐增大。选取桥墩双肢相同部位各节点进行横向比较,总结得出双肢薄壁桥墩具有平分荷载和延长寿命的特点。为提高桥梁整体抗震性能,采取联结桥墩增大截面的方式进行加固,对比加固前后两模型在同一地震作用下的结构响应,得出该方法在提高结构整体刚度方面,效果显著。     

区域垂直应变率动态图像与丽江(Ms7.0)、门源(Ms6.4)等强震关系的研究

利用从区域精密水准重复测量资料中分离提取区域性垂直应变率与跨断层形变观测相配合生成的动态图像方法,分析了发生于滇西和祁连山－河西地形变监测区及附近的丽江（Ｍｓ７．０）、门源（Ｍｓ６．４）等中强以上过程中的区域垂直应变率动态演化特征;在此基础上,对孕震过程区域垂直应变率动态信息的时空非均匀性与应变能积累状况的研究探讨,提出了一些根据区域垂直应变率动态信息判定中短期强震危险区的判据。     

松散堆积体工程边坡变形机理分析及支护对策研究

合理选择开挖坡比、正确认识变形破坏机理是影响松散堆积体边坡稳定性和施工安全的前提, 本文研究了西南地区某松散堆积体工程边坡的结构特征, 根据地形条件确定了合理的开挖坡比, 采用二维有限元研究了开挖边坡的变形机理并根据模拟结果确定潜在滑动面, 在此基础上, 提出支护对策。研究结果表明, 边坡由厚度达70m 的坡洪积、泥石流块碎石堆积体组成, 斜坡下部缓中部稍陡, 开挖平台位于缓坡部位, 根据地形条件结合坡体结构特征确定边坡开挖坡比为1: 0. 75; 数值模拟结果表明, 边坡变形开挖面附近及坡顶拉应力和坡体下部最大剪应力控制, 坡顶部位将首先产生拉张裂隙, 开挖边坡内部产生从坡脚部位向上发展的剪切变形, 滑面一旦与坡顶拉裂缝贯通, 边坡将产生整体失稳; 边坡采用锚拉桩、锚索框架、锚杆框架、排水相结合的综合治理措施进行支护。     

Experimental Study on Vortex-Induced Vibrations of Submarine Pipeline near Seabed Boundary in Ocean Currents

1 .IntroductionThe submarine pipeline is a commonfacility widely usedfor offshore oil and gastransport . Whena pipeline is installed on a seabed and not buried,unsupportedspans may exist insomelocations ,es-peciallyinthe uneven zones of the seabed.The spa…