全英文研究型教学效果探讨 ——基于有机材料化学课学生问卷调查分析

全英文研究型教学是值得探索的旨在提高人才培养质量的教学形式,因此多年来我们针对材料化学专业的专业必修课有机材料化学开展了全英文研究型教学的尝试与实践。为了解学生的英语学习现状、需求及教学效果,设计了开课前问卷和结课调查问卷。调查结果表明,学生有较好的英语水平,有学习用全英文讲授的专业课的内在动力和需求,对该课程的教材选择、英语讲授、教学内容及安排、教学方法和形式等方面的满意程度很高,全英文研究型教学不仅可行,而且可以取得很好的教学效果。     

“格网索引+MapReduce”策略下的地理国情统计分析研究

地理国情统计分析是深度研究地理国情普查数据的首要前提.针对现有单机集中式数据存储与处理方式存在耗时长、效率低甚至不支持的问题,设计了"格网索引+MapReduce"策略,基于规则格网设计普查数据文件的分块组织与分布式存储方式,研制了格网索引与空间分析相结合的双层过滤机制,构建基于MapReduce的地理国情并行统计算法.最后,与无索引MapReduce、ArcGIS平台进行性能对比测试,结果表明:"格网索引+MapReduce"方法的统计效率远高于ArcGIS平台,对无索引MapReduce方法亦有明显的效率优势,研究拟为地理国情普查数据的高性能、多类型、大批量统计分析提供优选方案.     

ICP-OES法测定地球化学样品中的铁

试样采用HCL、HNO3分解,制成2~3%王水溶液。在最佳条件下,用ICP-OES法测定地球化学样品中铁含量,测定范围为0.10~20%。方法简便快速,精密度和准确度能满足分析要求,符合地质矿产实验室测试质量管理规范(区域地球化学普查样品化学成分分析)。适用于地球化学调查样品批量样品中铁的测定,已应用于实际工作中,结果满意。     

重金属暴露与肾功能的关联性研究：基于代谢综合征人群的横断面研究证据

探索代谢综合征人群中重金属暴露与肾功能的相关性,为特定人群中慢性肾脏病的诊治提供新思路。基于2011—2018年美国健康与营养调查数据,纳入2 474名代谢综合征患者作为研究对象;探讨四种血液金属元素(包括镉、铅、硒、锰)对肾功能的影响。肾功能主要通过慢性肾病(CKD)、估计的肾小球滤过率(eGFR),尿微量白蛋白肌酐比(UACR)和尿酸(UA)评估。通过加权多因素Logistic回归模型及线性回归模型分析血液中金属元素水平与肾功能的关系。进一步按照年龄、性别、体质量指数(BMI)、是否患高血压、糖尿病及血脂异常进行亚组分析。研究发现血液中镉、铅水平与CKD的发生呈正相关,与eGFR呈现负相关。血硒与CKD的发生存在负向关联,而血锰与eGFR水平存在正相关(P<0.05)。而亚组分析结果显示,女性及老年代谢综合征患者对于金属暴露的效应更为敏感。代谢综合征人群中重金属暴露与肾功能存在关联,铅、镉暴露可能会导致肾功能受损,而硒、锰暴露则可能会起到一定的保护作用。     

Radiological mapping of Kelantan,Malaysia, using terrestrial radiation dose rate

Measurements of the environmental terrestrial gamma radiation dose rate (TGRD) in each district of Kelantan state, Malaysia, were carried out using a portable hand-held radiation survey meter and global positioning system. The measurements were done based on geology and soil types of the area. The mean TGRD was found to be 209 nGy h^–1. Few areas of relatively enhanced activity were observed in Pasir Mas, Tanah Merah and Jeli districts, which have a mean TGRD between 300 and 500 nGy h^–1. An isodose map of the area was produced using ArcGIS software version 9.3.     

敏感性问题调查方法的探讨

本文探讨了敏感性问题的四种调查方法，并结合实例进行比较，最后，对各种方法的优劣和应用范围提出作者的见解     

沥青路面破损图像自动检测系统设计

介绍了由承载车、计算机、路面破损图像采集子系统、路面破损定位子系统、路面破损图像处理子系统等组成的路面破损自动检测实验系统,根据理论分析确定了摄像机的安装位置参数。利用网络通信技术,实现了双CCD摄像机同步采集路面图像,同时对路面破损图像的几何畸变进行了校正。实验结果表明,该系统对典型的路面破损状态可以准确的检测识别。     

Indoor radon survey in dwellings of some regions in Yemen

Indoor radon survey in a total of 241 dwellings, distributed in some regions of Yemen was performed, using CR-39 based radon monitors. The objective of this radon survey is to get representative indoor radon data of three regions, namely Dhamar, Taiz and Hodeidah, situated at different altitudes above sea level. The radon concentrations varied from 3 to 270 Bqm⁻³ with an average of 42 Bqm⁻³. It was found that the average radon concentration in the surveyed areas increases with altitudes. The highest average radon concentration of 59 Bqm⁻³ was found in Dhamar city while the lowest average concentration of 8 Bqm⁻³ was found in Hodeidah city.     

On some optimum problems of vibration theory

Some optimum problems of vibration theory and the variational approach to their solution are discussed. The results of construction of optimum solutions obtained by means of necessary conditions of the calculus of variations are presented.     

Operator related attenuation effects in radiometric surveys

Radiometric surveys using airborne, vehicular mounted or backpack detector systems are increasingly used to identify and evaluate complex distributions of radioactivity in the environment. The signals detected depend on the energy and spatial distribution of radioactive sources, the material properties of the environment and the specific properties of the detector systems employed. Materials in close vicinity to the detector such as housings, and intermediate materials may have a critical impact on detection efficiency, and must therefore be taken into account in calibration. This study evaluates the effect of shielding by the body of the operator in backpack surveys. Controlled experiments using point sources and absorbers, chosen to represent the form and composition of human tissue, were conducted, and coupled to an analytical radiation transport model to estimate attenuation factors for mapping of ¹³⁷Cs. In this way generic factors to correct for this effect using portable spectrometers have been determined. The results compare well with observations at sampled calibration sites in Fukushima and the Solway area in Scotland. Reductions of the ¹³⁷Cs full-energy peak intensity between 20% and 30% may be expected depending on operator stature and the offset position of backpack systems. Similar effects may be present for other radiometric systems carried by a human operator.