高压蒸汽管道保温研究

计算了不同管径和保温厚度下蒸汽管道输送高压蒸汽的热损失和温度降。结果表明:保温厚度越大,蒸汽的热损失越小、温度降越小;保温材料导热系数与蒸汽的热损失呈正比;环境温度越高,蒸汽的热损失越小;环境风速对热损失的影响不大。同时研究了保温材料选择和保温结构对节能的影响。     

多孔介质微波加热厚度的确定

简述了微波加热的机理，以湿木材为研究对象，通过理论计算确定了微波在木材中的穿透深度。计算表明：随着木材含水率和微波工作频率的增加，微波在木材中的穿透深度减小；当用频率为915MHz和2450MHz的微波加热或干燥具有高含水率的多孔介质时，多孔介质的最大厚度应分别控制在16cm和6cm以内。     

2008~2016年MODIS多角度大气校正气溶胶产品在中国的时空分布及变化趋势

探究全国大气气溶胶分布及变化特征,准确了解中国地区气溶胶光学特性对研究大气环境污染、应对全球气候变化是非常重要的。对2008~2016年的MODIS MAIAC气溶胶光学厚度数据在中国的适用性进行验证,并采用Mann-Kendall方法,从不同的时空尺度和气溶胶类型上分析中国地区AOD值的时空变化特征。结果表明：①验证表明C6的MAIAC反演结果在中国AERONET匹配点上表现良好,C6的MAIAC反演AOD结果适用于中国区域;②从年际尺度上看,2008~2016年AOD年均值整体呈波动下降;从季节尺度上看,AOD季节变化呈春季整体高、夏季中心高、秋冬季水平低的特点,各省AOD平均值及各省份划区AOD平均值随季节变化趋势相似。③在空间上,AOD呈东南高、西北低、高值中心聚集的特征。④中国AOD变化整体呈现出东部减少且集聚,西部增加且分散的变化特征。可进一步探究不同种类气溶胶分布和气溶胶与典型大气污染物分布关系,以期为中国环境污染治理提供更好的决策指导。     

Delineating spatial distribution and thickness of unconsolidated sand along the southwest Lake Michigan shoreline using TEM and ERT geophysical methods

Erosion and accretion of various magnitudes occur along the southwest Lake Michigan shoreline. These processes are triggered by natural events and human activities, which affect the distribution and thickness of sand on the nearshore lake bottom. Significant erosion along the Illinois coastline has highlighted the need for a large-scale means of acquiring spatially rich data to build models of sand distribution along the entire shoreline. Thus, we implemented a high-resolution airborne transient electromagnetic (TEM) method, coupled with a ground-based electrical resistivity tomography (ERT) method to determine the sand distribution and thickness along the shore from the beach to ~1 km into the lake. From Kenosha, Wisconsin, to Chicago, Illinois, we acquired 1049 line-km of TEM data, and 13.43 line-km of ERT data. Our results indicated a distinct, uneven distribution and thickness of the unconsolidated sand unit covering the southwestern Lake Michigan shoreline. The unconsolidated sand unit was found to range in thickness from 0 to ~12 m. This unconsolidated sand unit was shown to be thickest (4.5 to ~10 m) in the northern part of the study site. In southern Wisconsin and Chicago, the sand layer beneath the water column was found to be very thin, ≤1 m. We propose, based on our analysis, that lake-bed conditions and wind direction are the main factors that limit southward littoral transport. Our data suggest that the current state of the shoreline is relatively analogous to how it has always behaved; however, anthropogenic disturbance has exacerbated the natural patterns of erosion and accretion.     

翼缘纵向变厚度工型截面梁变形性能试验

为研究翼缘纵向变厚度工型截面简支梁的变形性能,对2根翼缘纵向变厚度工型截面梁与2根等厚度梁进行静力加载对比试验,同时采用有限元软件ANSYS进行数值模拟.变厚度梁翼缘材料为Q345GJC等级纵向变厚度钢板,加载方式包括单点加载和两点加载.试验结果表明:试件均发生明显的板件局部屈曲;采用翼缘纵向变厚度工型截面简支梁,不仅可以在保证承载力的情况下大大减少用钢量,而且可以获得更大的强度储备;也可以达到密实截面的变形要求,满足塑性设计要求.有限元结果与试验结果吻合良好.该试验结果可为翼缘纵向变厚度工型截面钢梁的塑性变形设计提供依据.     

固体充填开采地表沉陷数值模拟研究

应用FLAC3 D软件建立了某矿区固体充填开采的三维数值模型,结合固体充填开采等效采厚的相关概念模拟了模型的开挖以及模型在开采后的移动变形情况。使用FLAC3 D内嵌的FISH程序语言,编制了相关程序,提取出两种不同类型的地表移动观测站的沉陷数据。利用提取出的地表移动观测站沉陷数据,结合MATLAB强大的数据处理和可视化功能,对固体充填开采所产生的地表沉陷进行后处理与可视化操作。研究表明：固体充填开采可以有效控制地表沉陷,适用于村庄等建筑物下采煤的情况;运用FLAC3 D并结合MATLAB的方法可以方便、准确的进行开采沉陷的数值模拟与可视化操作。     

Prying Force Calculation and Design Method for T-shaped Tensile Connector with High Strength Bolt

In order to establish the design method for T-shaped tensile connector with high strength bolt,the theoretical analysis is carried out. Firstly,it analyzes the performance of the connector and establishes prying force calculation model. Based on the model,prying force equation and function between bolt prying force and flange thickness is derived,and the min and max thickness requirement of flange plate under a certain tension load is then obtained. Finally,two simplified design methods of the connector are proposed,which are bolt pulling capacity method and flange plate bending capacity method.     

基于涡流检测的曲面涂层厚度影响因素分析

曲面涂层厚度测量已成为涡流检测实践中的一个重要课题.本文基于涡流检测技术研究了曲面涂层厚度检测的影响因素,使用ANSYS分析软件建立了曲面的三维涡流场有限元模型;通过定义材料属性,划分网格,设置边界条件,加载及求解等,计算了曲面的曲率半径大小、厚度以及提离距离变化对涡流信号的影响,分析了检测线圈阻抗变化与涂层厚度之间的对应关系.通过仿真,得到了曲面曲率的半径大小和厚度对涡流信号的影响规律,为实际检测曲面涂层厚度提供了可靠的理论依据和技术支持.     

胡襄煤田煤层厚度变化特征及其控制因素

根据河南胡襄煤田勘探钻孔资料,对煤层的稳定性和煤厚度变化特征进行研究。研究认为,区内二1煤层可采性指数为0.81,厚度变异系数为39%,属较稳定的全区大部可采的中厚-厚煤层;二2煤层可采性指数为1,厚度变异系数为11%,属稳定的全区可采的中厚-厚煤层;区内煤层厚度呈现东部厚西部薄的分布特征,局部出现无煤带或薄煤带;影响煤厚变化的因素主要为成煤时期地壳的不均匀沉降、成煤后期的古河流冲刷与断裂构造破坏作用。     

Effect of Mg-film thickness on the formation of semiconductor Mg2Si films prepared by resistive thermal evaporation method

Mg fi lms of various thicknesses were deposited on Si(111) substrates at room temperature by resistive thermal evaporation method, and then the Mg/Si samples were annealed at 40 ℃ for 4 h. The effects of Mg fi lm thickness on the formation and structure of Mg2Si fi lms were investigated. The results showed that the crystallization quality of Mg2Si fi lms was strongly infl uenced by the thickness of Mg fi lm. The XRD peak intensity of Mg2Si(220) gradually increased initially and then decreased with increasing Mg fi lm thickness. The XRD peak intensity of Mg2Si(220) reached its maximum when the Mg fi lm of 380 nm was used. The thickness of the Mg2Si fi lm annealed at 400 ℃ for 4 h was approximately 3 times of the Mg fi lm.