吹、吸气幕应用于排风柜的研究

针对现有排风柜技术的不足，引入吹、吸气幕技术，开发出一种新型吹吸、气幕式排风柜，并通过实验研究，数值模拟对照，得到了最佳设计参数。工程实例表明，这种新型排风柜具有节能，操作舒适，控制效果好的优点。     

多变量时滞计算的最大独立互相关算法

为解决相空间重构中多变量时滞参数难以同时选择的问题,提出一种基于最大独立互相关的时滞计算方法.将响应变量序列分段处理;对各段曲面拟合并将观测变量序列代入拟合函数;迭代运算至互相关最小,得到最优时滞.对最大独立互相关算法与遗传神经网络、互信息法、极大联合熵法进行对比实验,并引入联合递归图与共有近邻比值法作为评价方法,结果表明:最大独立互相关算法克服了传统方法的不足.选取某矿井下进风巷、上隅角、工作面和回风巷4个位置瓦斯浓度的真实数据进行四变量最优时滞选择实验并与互信息法对比,最大独立互相关算法的时滞计算结果为16-3-10-11,共有近邻比为0.58,联合递归密度为0.34%,优于传统方法.提出算法能够应用于实际多变量分析,具有一定实用价值.     

基于固定参数轨道的动态精密解算精度

为了验证动态精密解算在地震等连续运动平台中的应用效果,使用采样率为1 Hz的双频GPS接收机,并利用参数已知的轨道进行了动态模拟实验.以地震模拟动态平台进行实验,并利用GAMIT软件中的Track模块进行实验分析,通过对GPS数据的精密处理及对不同距离基准站数据的分析,得到了运动轨道图.结果表明:Track模块可使测量点的水平和垂直方向解算精度达到毫米级,说明此种解算方法适合在实际动态测量中进行应用,可以用来反演在地震发生时的地表动态变化情况.     

Three-dimensionally Ordered Macroporous Phosphotungstic Acid/SiO<Subscript>2</Subscript> for Efficient Catalytic Oxidative Desulfurization

Three-dimensionally ordered (3DOM) macroporous phosphotungstic acid/SiO₂ (HPW/SiO₂) materials were prepared by using colloidal crystal as templates and applied for oxidative desulfurization (ODS) of the model fuel oil. The obtained HPW/SiO₂ materials were characterized through scanning electron microscopy, powder X-ray diffraction, N₂ sorption, and Fourier transform infrared spectroscopy. The results indicated that 3DOM HPW/SiO₂ possessed hierarchical pore architectures which contained ordered macropores and disordered mesopores, with the Keggin type HPW embedded in the framework of pore structure. The removal rate of dibenzothiophene (DBT) could reach 100% under the optimum conditions, moreover. The performance was only slightly decreased for the regenerated catalyst after 7 cycles.     

改性碳纳米管/高密度聚乙烯复合材料正温度系数性能

以高密度聚乙烯(HDPE)为基体,改性的碳纳米管(CNTs)为导电填料,采用熔融法制备正温度系数(positive temperature coefficient,PTC)复合材料。通过扫描电子显微镜和热敏电阻曲线测试仪以及冲击试验机等,观察CNTs/HDPE复合材料的微观形貌,研究PTC效应随CNTs含量变化规律及对力学性能的影响。结果表明:CNTs在HDPE基体中分散性较好;当CNTS含量在体积分数为9%时,CNTs/HDPE复合材料的室温电阻率为102?·cm,PTC强度达4个数量级;HDPE基体中加入经过表面修饰过的CNTs后,复合材料的力学性能明显提高。当CNTs的体积含量在8%时,复合材料的冲击性能较纯HDPE提高了93%。     

绿色建筑自然通风的外围护结构设计

自然通风,长久以来就被作为一种必不可少的建筑技术.空调技术的发展虽然一定程度上削弱了自然通风在建筑设计中的重要地位,但随着能源危机和温室效应的推进,越来越多的建筑设计回归到运用自然通风来营造舒适的室内环境,降低建筑能耗.建筑的外围护结构,作为建筑室内外的分界点,对建筑室内外通风换气起着重要的枢纽作用.本文选择在自然通风上比较有代表性的绿色建筑的外围护结构作为研究对象,对其自然通风设计上不同的设计方法进行总结分类,将其分为附加构造措施、与空间设计的结合和双层皮幕墙3种类型,进行分别论述,为建筑外围护结构自然通风设计和选择提供设计参考.     

大学生手机依赖现状调查研究

为了解大学生手机依赖现状,采用手机依赖量表(MPAI),对1286名大学生进行了问卷调查。结果显示,26%的受访大学生存在手机依赖;手机依赖与性别、是否国助生具有显著性差异,女生比男生、非国助生比国助生更易形成手机依赖;手机依赖与年级存在相关关系,高年级学生的手机依赖比例高于新生。通过因子分析,提取冲突性、失控性、逃避性、焦虑性四个公共因子,提出手机依赖量表(MPAI)的四个新维度。从调查结果可以看出,大学生手机依赖现象较为普遍,女生、非国助生和高年级学生更易形成手机依赖,应当引起足够重视。     

Synthesis and physicochemical characterization of silica aerogels by rapid seed growth method

Thanks to the high optical transparency and ultra-low thermal conductivity, silica aerogels are ideal materials for energy-saving windows. However, their preparation is commonly based on either one-step base-catalyzed method, or two-step acid-base catalyzed method, which is difficult to inhibit the aggregation of clusters while keeping the size of clusters as small as possible and thus degrading silica aerogel's properties. Here, a new idea for synthesizing silica aerogels is presented from the viewpoint of controlling the growth and aggregation of silica clusters. A certain amount of Tetramethoxysilane (TMOS) used as seed precursor is firstly added into the mixture of methanol and distilled water for hydrolysis. A certain time later, the additional TMOS and a defined amount of ammonia are added to the obtained sol for promoting the rapid formation of the gel in several minutes. The silica aerogels prepared by this method have higher optical transparency and lower thermal conductivity than those prepared by the other two methods. This approach may also shed substantial light on controlling the microstructure of other materials prepared by sol-gel process.