共查询到17条相似文献，搜索用时 109 毫秒
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该论文为硕士学位论文 ,于 1999年 5月在中国科学院青海盐湖研究所完成。该论文采用 XRD、TG、DTA、显微照相和化学分析等方法研究明矾在等温 (空气气氛 )和非等温 (氮气气氛 )条件下的热脱水行为 ,并对明矾的生产工艺提出“两步脱水”的参考性建议。论文运用等温法研究明矾脱水后物相组成和脱水失重的关系 ,讨论明矾恒温脱水过程的机制 ,拟合各个脱水阶段所适用的动力学方程 ,并计算了相应的动力学参数。根据非等温的热分析曲线探讨了与热效应相对应的化学反应及每个脱水阶段的活化能。论文研究发现 ,明矾在脱水过程中存在着明显的“反… 相似文献
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本文报道了在四硼酸十八铝晶须材料制备实验中，原料明矾、脱水明矾和硼酸，以及制成品四硼酸十八铝晶须的熔样处理和分析方法，同时给出有关分析结果。 相似文献
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采用明矾与剧酸反应，在１１５０℃硫酸钾熔盐中合成硼酸铝（Ａｌ１８Ｂ４Ｏ３３）晶须，分别用水，不同浓度盐酸和不同浓度硫酸，在不同温度，不同搅拌速率下对烧结物进行浸溶实验，得到浸溶曲线，对反应产物进行物相鉴定，为硼酸铝晶须制备工艺中最佳条件的选择及硫酸钾回收提供依据。 相似文献
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闽清地处福建省东部、闽江下游。总面积约1466．57平方千米，人口30万。闽清工业向来以民间手工业为主，有陶瓷生产、砖瓦制作、纺麻织布、打铁铸锅、酱酒酿造、木竹加工、榨糖造纸、缝纫鞋革、雕刻印刷、粮油碾轧等行业。现在工业门类主要有陶瓷、冶金、电力、化工、造纸、机械、建材、酿造。食品、印刷、纺织和塑料等，主要产品有日用瓷器、电瓷、机制纸、工艺竹编、雨伞、味精、钨砂、钾明矾、瓷土、矽铁、蜜饯等700多种，近销国内29个省、市、自治区，远销东南亚、中东、欧美、港澳等30多个国家和地区。其中，发展历史最为悠久、所占比… 相似文献
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《Polar Science》2014,8(1):1-9
Water-soluble trace constituents affect the physicochemical properties of polar ice. Their structural distribution provides important insights into the formation history of ice and inclusions. We report the first finding of KAl(SO4)2·12H2O (potassium alum) and Al2(SO4)3·nH2O (aluminum sulfate) micro-inclusions in the Dome Fuji ice core, East Antartica, using a micro-Raman technique. Eutectic temperatures of these water-soluble species determined using thermal analysis were −0.4 °C for potassium alum and −8.0 °C for aluminum sulfate. Although the formation process of the aluminum-bearing sulfates remains unclear, the occurrence of these salts largely depends on ice depth. 相似文献
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James C. Hower 《Natural Resources Research》1995,4(4):310-324
The mining of cannel coal was a small, but prestigious, component of the coal production of Kentucky in the 1800's and early 1900's. Cannel coal was retorted into liquid fuel, gasified as an enricher of municipal gas supplies, and distilled as a feedstock for the production of chemicals. Each peak in usage was subsequently tempered by a discovery of cheaper sources of liquid hydrocarbons.Four mining areas in Kentucky, three in eastern Kentucky and one in western Kentucky, will be discussed. The Breckenridge deposit in western Kentucky was developed as early as 1837 and came to prominence in the 1850's and, to a lesser extent, in the 1880's. The Johnson County deposits were developed in the 1880's and continued in production through the 1920's. The Bell County cannels were developed in the 1890's. Although highly praised for their quality, they had a brief mining history because of the limited extent of the reserves. The most prolific cannel field, Morgan County, was opened in 1901 and continued to be a large producer, albeit with some low-production years, through the 1950's, with minor production as late as 1987.The production of cannel, as with any mineral commodity, was at the mercy of market demands and available transportation. Cannel coal, more than banded bituminous coal, occurs in relatively limited areas, leading to the rapid exhaustion of commercial deposits as well as failed attempts to develop deposits that did not attain commercial size. 相似文献
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农业资源利用效率的重新诠释与评价——以江苏省常熟市和江西省泰和县为例 总被引：1，自引：0，他引：1
本文重新诠释了农业资源利用效率的内涵,并建立一个新的农业资源利用效率评价框架和指标体系,以此完善和发展农业资源利用效率评价的理论与方法。论文选用多因素综合评价公式测算了常熟市与泰和县的农业资源利用生产率,运用包络分析法(DEA)计算了常熟市与泰和县的粮食生产配置效率。研究表明：①农业资源利用效率可以分解为农业资源利用生产率和生产配置效率两部分,生产配置效率又可进一步分解为纯技术效率和规模效率;②常熟市与泰和县的农业资源利用效率评价分值分别为0.967和0.984,农业资源利用生产率评价分值分别为0.953和0.922,生产配置效率分别为0.684和0.733;③常熟市粮食生产配置效率略低于泰和县,主要原因是常熟市粮食生产资源投入的冗余度(劳动、化肥、资本投入的冗余度分别为28.36%、23.45%和20.48%)高于泰和县(劳动、化肥、资本投入的冗余度分别为8.84%、8.83%和10.58%);④农业资源利用生产率的高低并不总与生产配置效率一致,农业资源利用效率评价应能兼顾这两者。 相似文献
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科技创新人才空间分布是科研实力、技术分布、发展潜力的表征。洞悉科技创新人才分布规律,从而科学制定人才战略,为科技创新驱动高质量发展和人才高地建设提供决策参考。论文通过粤港澳大湾区11个城市“十一五”至“十三五”期间科技创新人才的规模、密度、聚集指数、空间自相关性刻画其空间分布特征,结果如下：① 从“十一五”到“十三五”,粤港澳大湾区科技创新人才规模发展迅速,从约43万人增长到114万余人,但空间分布不均衡。② 深圳科技创新人才密度居粤港澳大湾区11个城市之首,单位人口人才密度约是最小值的7倍,单位面积人才密度约是最小值的190倍;江门、肇庆等地科技创新人才密度相对较低,低于大湾区平均水平。③ 深圳、东莞、广州有相对较强的科技创新人才聚集能力,而惠州、江门、肇庆聚集能力相对为弱。“十三五”期间,深圳、东莞、香港、珠海的聚集能力增强,澳门、中山、广州、佛山科技创新人才集聚能力有所下降。④ 粤港澳大湾区各城市科技创新人才分布特征与空间位置的关联性不强,大湾区人才高地建设各城市未有效联动形成合力。⑤ 城市生活基础保障的提升、科技创新发展环境氛围的营造和科技投入力度的增大会对粤港澳大湾区科技创新人才工作产生显著的正向影响,从而影响科技创新人才的分布特征。因此,结合国内外先进的理念做法,提出优化粤港澳大湾区科技创新人才分布格局,建设粤港澳大湾区科技创新人才高地的对策建议。 相似文献
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以山洪灾害风险评价的多准则决策模型、最大熵模型、信息量模型三种常见模型为研究对象,选取河西走廊和张掖市为地理区划（大中）、市域（小）空间尺度研究区,构建山洪灾害风险评价指标体系,分别完成基于三种模型的两种空间尺度的山洪灾害风险评价制图,基于甘肃省地质灾害调查与区划报告数据从模型验证、空间自相关、精度对比和尺度效应等角度对比分析三个模型应用于不同空间尺度的适应性,并给出优选模型。结果表明：最大熵模型是河西走廊（地理区划）空间尺度上山洪灾害风险评价的优选模型;多准则决策模型不适用于张掖市（市域）空间尺度评价,且三个模型运行结果均没有河西走廊（地理区划）空间尺度上表现良好;三个模型的尺度效应明显,在地理区划空间尺度上应用较良好,缩小至市域空间尺度上模拟结果误差增大;不同空间尺度上,最大熵模型均优于多准则决策模型和信息量模型,适用于地理区划（大中）、市域（小）空间尺度的山洪灾害风险评价。 相似文献
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ZhaoHui Joey Yang 《寒旱区科学》2019,11(1):1-12
Winter maintenance operations are crucial for pedestrian and motorist safety and public mobility on urban streets and highways in cold regions, especially during winter storms. This study provides a comprehensive literature review of existing deicing technologies, with emphasis on electrical resistance-heating deicing technologies for possible applications in areas with concentrated traffic, such as street intersections and crosswalks. A thorough review of existing and emerging deicing technology for snow/ice melting was conducted. The performance of various deicing methods was evaluated and the installation and operation cost of the electrical resistance-heating methods compared. Finally, current state of the practice of intersection/crosswalk winter maintenance was surveyed among state departments of transportation in North America. The intersection/crosswalk winter maintenance procedure adopted by the State of Alaska Department of Transportation and Public Facilities was described, and the annual winter maintenance and operation cost per intersection was estimated. It was found that the annual energy cost of an electrical resistance-heating method such as the carbon-fiber-tape deicing technology is about the same as the average annual maintenance and operation cost of current practice. In addition, an automatic electrical resistance-heating deicing system will bring benefits such as minimized delay time and improved safety for pedestrian and vehicular traffic in an urban application. 相似文献