网络传输丢包率对温室WSN测控系统的影响

针对温室无线传感器网络(WSN)测控系统中数据包易丢失的问题,通过对温室中一对强耦合因子温度和湿度进行解耦,建立温度、湿度非耦合的多输入多输出数学模型.在分析含数据传输丢包与时延的温室无线传感网络测控系统结构基础上,根据网络控制系统指数稳定的相关理论,分析了温、湿度离散控制系统指数稳定条件.利用Matlab中LMI工具箱,对系统的指数稳定性进行定量判断,求出满足温室WSN测控系统指数稳定的可行性解,在确保温室WSN测控系统指数稳定的情况下分析得出最大允许丢包率,为创建稳定的温室WSN测控系统提供理论依据.     

苍山洱海国家级自然保护区蝴蝶及其分布格局

基于野外调查和标本信息的研究表明,苍山洱海国家级自然保护区有蝴蝶10科113属199种(亚种),包括云南省新记录8种;东洋区系成分占优势,达63.8%,广布成分占33.0%,古北成分占4.8%;主要存在3种来源:印中亚界起源、印度或印马亚界起源及古北界起源;蝴蝶垂直分布格局表现为物种丰富度随海拔升高呈现出先增加后降低的单峰分布格局;利用聚类分析划分出4个生态地理昆虫带:1)干热河谷灌木丛草坡昆虫带(1400～1700m);2)山地亚热带常绿阔叶林昆虫带(1800～2 300m);3)中山温性针阔混交林昆虫带(2 400～2900m);4)亚高山寒温性暗针叶林昆虫带(3 000～3 400m)。     

留学生医学微生物学与免疫学实验教学实践

目的:探索留学生医学微生物学与免疫学实验教学的特点和方法.方法:运用全英文对留学生开展实验教学,课后随访并结合相关文献资料进行分析总结.结果:医学微生物学与免疫学是一门重要的医学基础课程,通过课前精心准备、采用灵活多样的教学方法、加强与学生交流和探索有效的考评制度,收到了良好的教学效果.结论:该教学方法适合于留学生医学微生物学与免疫学实验教学的开展.     

Research of 1 770 MPa galvanized steel wire for stay cable of domestic bridges

This paper focuses on introducing the manufacture technology of 1 770 MPa galvanized steel wires for stay cables applied to domestic bridges. During the development practices of high strength galvanized wire for stay cables used in Sutong Bridge, Baosteel has established three key technologies based on research of manufacture technology and technical innovation. The three key technologies are： ＂Double Tensioning ＋ limiter die＂ process, ＂dominant process ＋ fine adjustment＂ in integrated optimization technology and ＂three-level control＂ in hot dip galvanization. With these key technologies, Baosteel has produced 1 770 MPa galvanized wires for stay cable, which has high tensile strength, low relaxation and good torsion performances.     

草街冲砂闸闸墩C25混凝土施工温度观测反分析

基于闸墩C25混凝土现场原型试验,采用混凝土非稳定温度场求解的有限元仿真计算技术,集成了混凝土内部冷却水管的离散模型和迭代算法,根据现场温度实测资料,结合优化遗传算法对闸墩试验段混凝土温度场进行了反演分析.研究表明,反演所获取混凝土特性参数能较好体现工程实际情况,为温控仿真计算和确定温控防裂措施提供了重要保证.     

Novel method of ordinal bearing estimation for more sources based on oblique projector

A novel direction of arrival (DOA) estimation method is proposed when uncorrelated, correlated, and coherent sources coexist under color noise field. The uncorrelated and correlated sources are firstly estimated using the conventional spatial spectrum estimation method, then the noise and uncorrelated sources in Toeplitz structure are eliminated using differencing, finally by exploiting the property of oblique projection, the contributions of correlated sources are then eliminated from the covariance matrix and only the coherent sources remain. So the coherent sources can be estimated by the technique of modified spatial smoothing. The number of sources resolved by this approach can exceed the number of array elements without repeatedly estimating correlated sources. Simulation results demonstrate the effectiveness and efficiency of our proposed method.     

大学生心理健康与主观幸福感相关研究

目的：研究大学生心理健康与主观幸福感指标的相关。方法：采用《精神症状自评量表》（SCL-90）和《综合幸福感问卷》（MHQ）测量了107名大学生。结果：（1）幸福指数及各维度与SCL-90总均分及各维度存在显著负相关;（2）逐步回归分析显示,抑郁、恐怖和强迫可解释幸福指数的20%变异,强迫因子解释生活满意的22%变异,抑郁分别解释正性情感12%变异,负性情感11%变异。结论：心理健康指标评估应包括正负两个指标系统,抑郁是影响大学生主观幸福感的核心因素。     

Ultra-high cycle fatigue behavior of high strength steel with carbide-free bainite/martensite complex microstructure

The ultra-high cycle fatigue behavior of a novel high strength steel with carbide-free bainite/martensite (CFB/M) complex microstructure was studied. The ultra-high cycle fatigue properties were measured by ultrasonic fatigue testing equipment at a frequency of 20 kHz. It is found that there is no horizontal part in the S-N curve and fatigue fracture occurs when the life of specimens exceeds 107 cycles. In addition, the origination of fatigue cracks tends to transfer from the surface to interior of specimens as the fatigue cycle exceeds 107, and the fatigue crack originations of many specimens are not induced by inclusions, but by some kind of "soft structure". It is shown that the studied high strength steel performs good ultra-high cycle fatigue properties. The ultra-high fatigue mechanism was discussed and it is suggested that specific CFB/M complex microstructure of the studied steel contributes to its superior properties.     

含腐殖酸的淀粉/聚丙烯酸缓释肥包膜材料的制备及性能研究

采用水溶液聚合法,以N,N-亚甲基双丙烯酰胺为交联剂,过硫酸钾为引发剂,通过添加腐植酸,淀粉与丙烯酸共聚交联,制备了一种高吸水缓释肥材料.腐植酸、淀粉和丙烯酸的最佳质量配比为8∶20∶72.此时,材料具有最大吸水率:659 g/g(去离子水)、425 g/g(自来水).尿素缓释肥的缓释周期为60 d,符合GB/T23348-2009规定的缓释效果.     

住宅建筑气候适应性通风调控方法

为得出住宅建筑室内可接受热环境的气候适应性通风调控方法,根据适应性模型理论,以aPMV模型为基础,结合重庆地区的调研结果分析得出住宅建筑室内可接受的温度范围;基于状态空间法对重庆地区住宅建筑常用的通风调控技术进行分析研究,包括不同换气次数和分时段设置通风对室内温度的作用分析,从房间温度整体分布角度提出了重庆地区通风技术的分月调控方法;结合室外温湿度等参数的温湿图,具体分析了通风调控对室外气候参数的调控有效区域,得到各月通风调控方法的气候适应性区域。提出的基于室内热舒适适应性模型的可接受热环境的通风调控策略有利于建筑的热工设计和寻求设备的经济运行方式。