旅游管理专业研究生《地理信息系统》课程教学改革探讨

在智慧旅游时代,掌握GIS基础理论知识和技术技能对于旅游专业学生来说非常重要.本文从旅游管理研究生GIS课程目标发出,结合实践教学经验,分析了该课程在教学过程中存在的一些问题,从教学内容、教学方法和考核方式三个方面提出切实可行的GIS课程教学改革建议,以提升课程教学质量和研究生的科研素质.     

滨海盐土盐分空间分布的条件模拟和不确定性研究

以海涂围垦区为例,利用普通克立格插值法和序贯高斯条件模拟方法对土壤盐分的空间分布进行估值和模拟,并利用序贯指示条件模拟进行不确定性评价.结果表明,样区东南区域土壤盐分含量较高而北部区域盐分含量低.由普通克立格法得到的土壤盐分的空间分布整体比较连续,具有明显的平滑效应,估值结果数据的分布频率趋于平缓.序贯高斯条件模拟结果整体分布相对离散,突出了原始数据分布的波动性,其模拟结果数据的分布频率相对集中.预测精度上,序贯高斯条件模拟的预测结果精度相对较高.以评价标准204 mS m-1作为土壤盐分含量的阈值进行的序贯指示条件模拟结果显示,在土壤盐分含量较高的东南部地区,超过阈值的概率超过75%,而北部很多盐分相对含量低的地区,超过阈值的概率值都低于25%.以超阈值概率为0.9、0.85和0.8三个值来选取盐分的高值风险区进行空间不确定评价,结果表明,联合概率比单点统计的概率更为严格,在划分较大范围高盐风险区域时,最好同时采用联合概率来进行信度评价.     

压力容器环焊缝X射线透照内外对中简易方法

本文通过压力容器内外壁周长差异出两个经验公式，借此可对透照部位快速对中。     

原位合成TiO2纳米管阵列及其光催化性能研究

采用液相沉积法(LPD), 以阳极氧化铝(AAO)为模板, 原位合成高度有序的TiO₂纳米管薄膜材料. 实验结果表明, 经过400℃热处理后, 制备的TiO₂纳米管为锐钛矿相, 长度达5μm, 管外径为150nm左右, 管壁厚为25nm左右. 热处理后的TiO₂薄膜具有良好的光催化降解甲基蓝的性能, 即经过120min卤灯照射后, 甲基蓝被完全降解.     

大型冷库软木粘贴施工

本文详细介绍了冷库软木粘贴工艺和施工中应注意的问题。冷库以制冷、贮藏为主要功能,而土建施工中的保温隔热项目是保证其制冷贮藏的主要条件     

Durability experiment on anti-electron-bombardment of RE2O3-Mo secondary emission material

A durability test to determine anti-bombardment sensitivity of multi-RE2 O3-Mo secondary emission material was carried out and the variation of maximum secondary emission coefficient (δmax) was monitored at regular intervals. After the experiment, the cathode was analyzed with SEM, EDS and XRD techniques. The results show that δmax of multi-RE2O3-Mo cermets cathode heated to 1 100 ℃ under electron bombardment of 300 W/cm2 reaches the peak of 3.35 at 200 h. After 500 h of bombardment, the maximum secondary-electron-yield curve stabilizes. The δmax value of the cathode remains at about 2.5 after 1 000 h and represents a good anti-bombardment property. The high δmax value of the cathode is related with formation of an enriched Y2 O3 layer on the surface under high temperature and with the amount of La2 O3 particles in the shape of nanometer distributed on the surface. Under the experimental conditions, the drop of δmax value may be caused by the reduction of La2 O3 content and the porous layer resulted from evaporation of MoO2, which is formed when Mo at the surface is oxidized.     

复合稀土氧化物-钼-铼金属陶瓷阴极的次级发射性能

研究了复合稀土氧化物-钼-铼金属陶瓷阴极的二次电子发射系数和抗暴露大气性能,对发射后的表面进行了表面分析,并与单元、复合稀土-钼金属陶瓷阴极进行了对比.研究结果表明:加入微量铼的复合稀土氧化物-钼金属陶瓷阴极的二次电子发射系数可提高8%,其最大次级发射系数δm为2.65,且具有较好的抗暴露大气性能.     

La2O3-Gd2O3-Mo secondary emission material

A new kind of materials La2O3-Gd2O3-Mo has been produced by powder metallurgy method.The composition and microstructure of the material were studied by XRD and SEM.It shows that no chemical reaction takes place among La2O3,Gd2O3,Mo and the rare earth oxides exist along molybdenum grain boundaries and in the pores.The emission property measurement results of this material show that adding rare earth oxide into molybdenum can improve the secondary emission coefficient of the emitter,and the emission property depends on the activation temperature.After La2O3-Gd2O3-Mo was activated at 1360℃,the maximum secondary emission coefficient can be high to 2.62,which has exceeded that for practical uses(2.0).     

矿用橡套电缆故障电火引燃矿井沼气故障形成时间的测定

阐述了矿用橡套电缆故障电火引燃矿井沼气故障形成时间的测定.通过大量的模拟试验证明矿用橡套电缆的最小引燃时间为5ms,这一数据与国外的研究成果一致,为实现矿井“整体防爆”安全研究工作提供了依据.