我国粮食生产布局变化特点及其成因分析

建国以来,我国粮食生产呈波浪型上了四个台阶,粮食总产量分别达到２亿ｔ、３亿ｔ、４亿ｔ、ｔｗｎ ｔ。总的来说,粮食产量呈现超伏涨落但缓慢上升的趋势。过去５０年,我国的粮食生产及布局发生了巨大的变化。首先,粮食增长逐渐由以前的单产和总产并重转变为以提高单为主。其次,粮食结构也发生了变化,很长一段时间,我国的粮食增长主要信赖于水稻增产,８０年代以后,水稻在粮食生产中的比重迅速下降,而小麦和玉米所占比重帽     

我国的环境现状,类型与变化

本文结合区域的社会经济发展状况，通过采用一定的数学模型，分析了我国区域环境现状、类型及其变化，得出了一些有参考价值的结论。     

新疆煤田火灾的成因、危害及综合治理

新疆是世界上煤田火灾最严重的地区,原因主要是新疆地处欧亚大陆腹地,具典型的大陆性干旱气候;新疆地区煤系为中下侏罗纪,地质活动较为剧烈;小煤窑的乱采滥挖等.新疆煤田火灾带来巨大危害:损失煤炭资源、污染环境、引发地质灾害、破坏生态平衡及危害生物健康等.对煤田火灾进行综合治理已经成为当务之急.为了有效灭火,应先对火区进行探测.探测方法有磁异常探测法、自然电场法和红外地面测温法等.然后因地制宜地选择适当的灭火技术进行灭火.灭火之后还应利用地理信息系统等方法对火区进行动态监测.     

WATER SUPPLY IMPACTS OF NUCLEAR FALL1

ABSTRACT: “Nuclear winter,” more properly called “nuclear fall,” could be caused by injection of large amounts of dust into the atmosphere. Besides causing a decrease in temperature, it could be accompanied by “nuclear drought,” a catastrophic decrease in precipitation. Dry land agriculture would then be impossible, and municipal, industrial, and irrigation water supplies would be diminished. It has been argued that nuclear winter/fall poses a much greater threat to human survival than do fall out or the direct impacts of a conflict. However, this does not appear to be true, at least for the U.S. Even under the unprecedented drought that could result from nuclear fall, water supplies would be available for many essential activities. For the most part, ground water supplies would be relatively invulnerable to nuclear drought, and adequate surface supplies would be available for potable uses. This assumes that conveyance facilities and power supplies survive a conflict largely intact or can be repaired.     

上海市的灾害隐患及减灾对策

本文从上海市特定的环境角度出发,论述了本市存在的重大灾害隐患,进而提出减轻这些灾害的对策和建议。     

石油天然气项目管理落实《安全生产法》探析

项目管理是石油天然气生产企业建设项目施工组织的最基本的管理方式。针对建设项目HSE管理存在的问题和短板,文章从建设项目常见问题和风险的分析入手,根据新《安全生产法》(以下简称"新安法")对建设项目的要求,从6个方面分析现阶段石油天然气行业建设项目HSE管理面临的新形势、新要求,针对性地提出加强建设项目HSE管理的主要举措:加强设计源头风险防控、关键环节风险管控、专业化风险管控、施工人员风险管控、施工现场风险管控、投产后期风险管控。对如何强化建设项目全过程风险管控提出建设性意见。     

Application of an odd/even predominance of n-alkanes in oil–source rock correlation: taking the lower Paleozoic strata of the Tarim Basin as an example

The composition and distribution of n-alkanes carbon numbers reflect the source of kerogenic organic matter, sedimentary environment, and maturity of the rocks. The comparison results of the n-alkanes GC (gas chromatography) chromatograms in the Tazhong Low Uplift show that the n-alkanes of the source rocks in Upper Ordovician display an odd carbon number predominance. At the same time, Cambrian–Lower Ordovician exhibit an even carbon number predominance. The correlation between oil and source rock illustrates that crude oils in the fields of well TZ10-12 and well TZ24 stem from the Upper Ordovician source rocks. The origins of the crude oils in the fields of well TZ161-162 and well TZ45 are Cambrian–Lower Ordovician. The strata corresponding to the crude oils with odd/even carbon number predominance match the oil–source rock correlation. Thus, the characteristics of odd/even carbon number predominance in n-alkane compounds are effective for oil–source rock correlation in the Tazhong Low Uplift, Tarim Basin.