巨厚砾岩下开采地表沉陷预计模型的改进

为了探究巨厚砾岩下开采的地表沉陷规律,结合关键层理论,通过数值模拟从垂直应力、塑性区、垂直位移3个方面分析覆岩内部稳定性及造成地表倾向下沉曲线偏态的原因,基于概率积分法,建立改进的地表沉陷预计模型。结果表明:关键层初次破断距为291 m,周期破断距为281 m;悬力臂是造成下沉曲线偏态的主要原因;相对于经典的概率积分沉陷预计模型,改进的地表沉陷预计模型相对误差减小114%。可见在巨厚砾岩层下开采地表沉陷预计中,改进的地表沉降预计模型具有较高的准确度和适用性。     

长三角地区常用遥感降水产品质量评估

长三角地区是中国经济最发达地区之一,选定较好的卫星降水产品是进行科学防灾减灾的重要环节.基于地面气象站降水实测数据,采用7种指标对目前中外常用遥感降水产品热带降水任务卫星(tropical rainfall measurement mission,TRMM)、气候预测中心校正产品(climate prediction center morphing technique,CMORPH)、全球降水计划数据集(global precipi-tation measurement,GPM)以及中国自动站与CMORPH降水产品融合数据集(China merged precipitation analysis,CMPA)在长三角地区的适用性进行评估.结果表明:在年尺度,CMPA产品质量最优,相关系数达到0.95;在季节尺度,冬季GPM最优,夏季TRMM最优;平原地区比山区地区的产品质量要好.融合多降水产品的高精度产品未来将成为科学防灾减灾的重要数据.     

甘蓝型油菜BnHY5基因的表达模式及非生物胁迫响应分析

为探究甘蓝型油菜中HY5的表达情况,首先通过甘蓝型油菜基因组数据分析预测HY5及其同源基因HYH(HY5-Homologous),克隆获得了四个HY5(命名为BnHY5)以及三个HYH(命名为BnHYH)重复基因全长cDNA序列.其次,对BnHY5进行了蛋白结构预测、理化性质分析,研究结果表明:BnHY5蛋白为不稳定、亲水性蛋白,主要结构域为亮氨酸拉链.最后,探究了甘蓝型油菜中该基因的表达情况,用荧光定量PCR分析了BnHY5重复基因表达模式和响应非生物胁迫的情况,BnHY5四个基因中,BnHY5-2的表达水平最高,BnHY5-1、BnHY5-2不存在组织表达差异且表达水平高于BnHY5-3、BnHY5-4.BnHY5基因不仅响应高温、低温、镉、高盐非生物胁迫,而且参与ABA和GA_3激素信号响应,说明BnHY5在逆境胁迫中有重要作用.此外BnHY5重复基因在非生物胁迫下的表达模式发生改变,BnHY5四个基因的表达占比与不同类型胁迫处理相关,存在表达差异.     

基于蚁群优化算法的云计算资源负载均衡研究

针对云数据中心虚拟机分配物理机时存在负载不均衡的问题,提出了一种基于蚁群优化算法的资源调度算法.对问题场景进行了分析,提出了数据中心负载不均衡度以及物理机与虚拟机之间不匹配度的概念,并给出了问题的形式化描述.在蚁群算法选择概率规则中参考了用户对虚拟机资源的需求,尽量避免对相同类型虚拟机部署在一台物理机上,同时对信息素的初始化、信息素的更新进行了改进.通过CloudSim模拟平台进行仿真实验,并与其他的分配算法进行了比较,实验结果表明:该调度算法能够快速地完成虚拟机的放置,并且使云数据中心的物理机具有较低负载不均衡度,提高了资源的利用率.     

Characterization of dissolved organic matter in a dynamic membrane bioreactor for wastewater treatment

This paper systematically examined the characteristics of dissolved organic matter(DOM) in a dynamic membrane bioreactor(DMBR) for municipal wastewater with a laboratory-scale continuous-flow device.Experimental results showed that the system performed excellent pollutants’ removal efficiencies.The increase of trans-membrane pressure(TMP) for the dynamic membrane(DM) could be divided into three stages,i.e.,zero increase stage,slow increase stage and abrupt rise stage.The maximal fouling rate of the DM reached to 4.34 kPa/h in abrupt rise stage.It was observed that the polysaccharides(PS) concentration of DOM samples gradually increased from the anaerobic zone to the aerobic zone in sequence,but the proteins(PN) concentration performed an opposite trend.The DM could retain a small part of the large molecular substances(>10 kDa) in the aerobic zone.Two particular fluorescence peaks appeared in the anaerobic zone and in the anoxic zone were also found in the effluent,which illustrated the dynamic cake layer closed to the stainless steel mesh might induce an anaerobic/anoxic micro environment.Based on the three-dimensional excitation-emission matrix(EEM) fluorescence spectroscopy analysis,aromatic proteins,aromatic proteinlike substance,fulvic acid-like substances and soluble microbial by-product-like materials could be biodegraded effectively in the DMBR,and the DM could partly remove the humic acid-like substances and soluble microbial by-product-like materials.     

Shape demagnetization effect on layered magnetoelectric composites

Magnetoelectric （ME） voltage coefficient of plate layered magnetostricUve-piezoelectric composites was always considered independent of the in-plane size due to the oversimplification in ME theoretical models. Here we report that the ME voltage coefficient depends on the in-plane size owing to shape demagnetization effect on magnetostriction. Both theoretical analysis and experimental results indicate that ME voltage coefficient of layered ME composites changes with the variation in in-plane sizes （length and width）. ME coefficient increases with a rise in in-plane sizes, and different aspect ratio also results in different ME coefficients. Proper design of in-plane shape will greatly promote the development of ME devices.     

浅谈青藏铁路多年冻土区现浇基础式涵洞施工工艺

多年冻土区现浇基础式涵洞施工,关键是如何保证基础开挖、砼浇筑等施工过程中对基底多年冻土的热扰动最小,从而保障结构物的稳定与可靠。     

Mobile Technologies Adoption: An Exploratory Case Study

Based on the theory of task-technology fit and literature review of mobile technology acceptance, a research model is presented based on the features of mobile technologies and the actual usage of mobile applications in business environments, which identifies the characteristics of mobile applications and fitting tasks. An exploratory case is studied to understand how ABC Company, Hong Kong, utilizes mobile selling applications in their sales management process. This study gives some managerial suggestions for enterprises to successfully use mobile applications.