珠穆朗玛峰北坡绒布冰川区水体的化学特征

１９９７－０５在珠峰地区绒布冰川采集的４类水样的实测资料表明,本区各类水体都呈碱性,ＰＨ值的大小顺序为：湖水〉湖水〉表层雪。河水和湖水的阴离子以ＳＯ＾２－４为最大,而表层雪样品以Ｃｌ－最大;     

The relevance of James Lovelock’s research and philosophy to environmental science and academia

James E. Lovelock, famed for his Gaia hypothesis, which views the Earth as a living integrated and interconnected self-regulating system whose equilibrium comes about from complex energy-based interactions and feedback loops, ultimately sustaining life, passed away at the end of July, 2022 at the age of 103. Not only are the adaptive mechanisms of Gaia central to the conversation of environmental homeostasis, they lie at the heart of climate change and global warming. Lovelock is also remembered as the co-inventor of the electron capture detector that eventually allowed for the sensitive detection of chlorofluorocarbons and pesticides. Finally, Lovelock’s free-spirited nature and research independence allow academia to rethink current research’s modus operandi.     

提高前向散射型光电感烟探测器性能的算法

以国家科技部973项目中建立的火灾探测应用环境及火灾信息数据库为依据,对目前使用最为广泛的前向散射型光电感烟探测器固有特性的归纳和分析,通过数据挖掘,提出一种切实可行的算法处理技术和智能判断火灾方法,有效提高了现有前向散射型光电感烟探测器的火灾探测及其抗干扰能力。     

2011~2017年中国PM2.5多尺度时空分异特征分析

PM_2.5时空分异特征认知对大气污染联防联控意义重大,本文从空间多尺度的视角出发,利用空间模式分析方法与地理探测器,对2011~2017年中国大陆地区PM_2.5年均浓度时空分布格局及成因进行探究,从而揭示PM_2.5多尺度时空分异特征.结果表明：①2011~2017年PM_2.5年均浓度相对稳定,无明显趋势,国家与区域尺度PM_2.5变化特征基本一致,呈现"W"型变化,整体上看,污染程度由高到低依次为：中部、东部、西部与东北.②由空间模式分析结果可知,高值聚集区主要位于中国的东部、中部以及新疆的西南地区,低值聚集区则集中在青藏、云贵高原以及大兴安岭地区.③地理探测器分析结果证实：城市化因素中人口密度是国家与区域尺度上PM_2.5时空分异的主导因素,同时,产业、能耗与交通因素对PM_2.5分布格局存在不同程度影响.在区域尺度上,除了人口密度因素之外,工业用电量与公车总量对中部地区PM_2.5年均浓度影响较大,东部地区是工业烟粉尘排放量与道路面积,东北地区则为第二产业产值占比与城市绿地率,社会经济因素对西部地区的PM_2.5年均浓度影响不显著.     

3种染料化合物在UV-TiO2/H2O2和UV-TiO2体系中的光催化降解研究

采用自制的TiO2膜和平板式固定床型光催化氧化反应装置,对甲基橙、茜素红和罗丹明B 3种含有不同生色基团的染料化合物进行了TiO2光催化氧化降解研究,通过对照测定降解过程中吸光度、电导率、pH的变化,分析了在加入和不加入H2O22种情况下降解过程的异同,比较了3种染料化合物脱色的难易程度,揭示了降解产物中无机离子的变化规律及某些可能的产物类型.     

Neutron activation analysis of ceramic tiles and its component and radon exhalation rate

IntroductionCeramic,consistofearthymaterialslikeclaykaolin ,limestoneandsandglass .Ceramicmaterialsarenonmetalic ,inorganiccompoundsprimaryoxides ,alsocarbides ,nitridesandsilicides .Twotypesofbondingmechanismsoccurinceramicmaterial ,ionicandcovalent.Theo…     

AlN覆铜板盐雾环境下的退化行为研究

目的 研究AlN覆铜板在盐雾环境下的性能退化及其微观机制。方法 采用交替喷雾和干燥方法对AlN覆铜板进行15周期的中性盐雾试验,并在第1、3、6、10、15周期时检测其相关性能。主要通过击穿电压测试、介电性能测试和导热性能测试等方法,分别评价AlN覆铜板的电绝缘特性、介电损耗及导热系数,并通过扫描电镜和能谱测试对试样表面/截面微观形貌和元素变化进行分析。结果 AlN覆铜板导热系数和击穿电压随盐雾试验周期的增长而逐渐退化,最大退化率分别为13.2%和73.8%。介电损耗明显增加,盐雾试验15周期后,在低频区域的最大值约为1.3。Cu电极发生明显腐蚀,生成大量绿色腐蚀产物,导致表面Ni-P镀层脱落失效。H₂O分子扩散进入AlN陶瓷内部,在局部区域造成陶瓷水解,逐渐形成微裂纹。结论 盐雾试验过程中,Ni-P镀层逐渐开裂剥落,Cu电极表面最终形成大面积疏松多孔的腐蚀产物层。H₂O、Cl^–、Na⁺等逐渐溶解扩散进入AlN陶瓷,导致陶瓷中空位、裂纹、杂质缺陷浓度增加,二者都会增强导热过程中的声子-缺陷散...     

Radiometric and environmental impacts of mill tailings at experimental plant processing unit,Allouga, Egypt

Abstract

Uranium mining and ore processing are known to be harmful to the environment and human health if the waste generated is not managed properly. The aim of the present study is to determine the radiological indices in the mill tailings and review the possible attempts to utilize and minimize its hazardous effect. The activity concentrations of natural radionuclides, ²³⁸U, ²³²Th, ²²⁶Ra, and ⁴⁰K have been measured by gamma spectrometry using HP-Ge detector. The average activity concentrations of ²³⁸U, ²³²Th, ²²⁶Ra, and ⁴⁰K in the tailings wastes were 2071.8, 59.92, 6921.262, and 445. 57?Bq/kg respectively which are higher than the international average limit. The ranges of hazard indices such as Radium equivalent activity (Ra_eq), external hazard index (H_ex), internal hazard index (H_in), γ-radiation hazard index I_γ, Dose rate (nGy/h) and annual effective dose equivalent (AED), were estimated. Uraniumm isotopic ratios in the ore –material and mill tailing samples indicate migration out of radionuclides to the surrounding environment causing contamination and many dangerous diseases. Fairly, all investigated tailing waste samples do not satisfy the universal standards, the studied wastes relatively still have high uranium contents and need reprocessing.     

Influence of thermal environment on metallographic structure characteristics of the electric arc bead pattern

Electrical apparatuses are prone to arc, which generally causes a fire, even an explosion hazard, when a flammable gas mixture is present, especially during industrial processes. Terrible fire scenes are challenging for fire investigations. In this work, by performing a simultaneous thermal analysis test we simulated a fire environment and found that as the oxygen concentration decreased, the oxidation/exothermic peak temperature of ‘cause’ bead became higher, but the melting temperature was unaffected. Results indicated that the bead pattern underwent oxidation at approximately 831 °C, melting initiated at approximately 1060 °C, and the pattern then disappeared. The melted pattern grain changes were divided into three critical temperature stages: Approximately 600 °C, the onset temperature at which the melted pattern grains began to be equiaxed; approximately 831 °C, at which the grains were interspersed with oxygen-containing material; and 831–1060 °C, when the grains disappeared, which is a criterion for identifying electrical fires. However, the boundaries remained throughout the thermal environment process. Moreover, the bead pattern demonstrated three metallographic regions: Deep layer (Region I), the intermediate layer (Region Ⅱ), and surface layer (Region Ⅲ). Region I was the most thermally sensitive, in which equiaxed crystals first appeared. Region Ⅲ was the thermal reaction lag zone, in which the typical branching crystals finally disappeared, and Region Ⅱ was intermediate between Regions I and Ⅲ. The results may help fire investigators determine the fire scene temperature stages and provide support for fire evidence extraction.     

IMPACT OF SURFACE COAL MINING ON THREE OHIO WATERSHEDS –PHYSICAL CONDITIONS AND GROUND-WATER HYDROLOGY1

ABSTRACT: A study was conducted over a six-year period in East-Central Ohio to determine the effects of surface mining and reclamation on physical watershed conditions and on ground-water hydrology in three ground-water zones in three small experimental watersheds. Mining disturbances in watersheds adjacent to the experimental sites affected ground-water levels in the undisturbed experimental watersheds prior to actual mining in the experimental sites. New subsurface flow paths, with different characteristics, formed during mining and reclamation. At all three sites mining dewatered the saturated zone above the underclay of the mined coal seam. Mining and reclamation affected ground-water levels below the mined coal seam in the middle and lower zones within at least two sites. Ground-water level recovery in the mined upper saturated zone was slow and irregular both temporally and spatially after reclamation. Hydraulic conductivities of postmining (Phase 3) spoil were generally greater than those of Phase 1 bedrock, but wide spatial variability was observed. Modelers need to be aware of the complexities of new flow paths and physical characteristics of subsurface flow media that are introduced by mining and reclamation, including destruction of the upper-zone clay.