51 resultados para Diderot, Denis, 1713-1784


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通过野外控制实验,研究了高寒矮嵩草草甸群落植物多样性、初级生产力对模拟降雨条件的响应.结果表明:(1)在植物生长期(6月),增加降雨20%、增加降雨40%,植物群落物种多样性指数(H)和均匀度指数(J)分别比对照提高了0.188和0.011、0.735和0.076,生长期(7月)增加降雨20%物种H和J提高了0.409和0.07;(2)禾草类:增加降雨20%处理的地上生物量与对照相比没有明显的显著性差异(P>0.05),增加降雨40%处理的地上生物量与对照相比差异显著(P<0.05),说明过多增加降雨会抑制禾草的生长发育.杂类草:减少降雨50%处理的地上生物量与对照相比差异显著(P<0.05),其地上生物量对减少降雨的反映比较敏感.莎草类:其地上生物量对增加和减少降雨都没有显著变化;(3)0~10 cm和0~30 cm土层地下生物量均在增加降雨20%时最高,地下生物量的总量也在增加降雨20%时最高;(4)矮嵩草草甸地下生物量与地上生物量、总生物量的比值接近于生长季末时最大,且在模拟增加降雨20%的水平时,7、8、9月份地下和地上生物量较其它处理组高.

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In Dongpu depression, there are obviously overpressure phenomena below 2000-3200m. Research to the relationship between sedimentation-diagenesis and overpressure of reservoirs is in great need. In this paper, after analyzing and simulating the overpressure in Wendong, Qiaokou and Baimiao regions, we draw a conclusion that the fast sedimentation since Low Tertiary is one of the most important mechanisms for the formation of overpressure in Dongpu Depression. The gypsum in northern part of Dongpu Depression is the good seal for the development of overpressure. On the base of detailed work to the distribution and magnitude of overpressure in Wen-qiao-Bai regions, we selected several wells that have different overpressure to find the sedimentary and diagenetic differences of these wells. We find that compaction is obviously inhibited in overpressured reservoirs, which results in the linear relation between physical properties of reservoirs and sedimentary parameters, such as sorting coefficient, the content of matrix, etc. Reservoirs with great magnitude of overpressure have undergone more extensive erosion than the ones with low magnitude of overpressure, which probably is the result of the great solubility of CO_2 under high pressure. The great burial depth, the high content of matrix and the extensively developed cement of carbonate are the most important factors that influence the physical properties of reservoirs in Dongpu depression. Overpressure plays a constructive role in the physical properties of reservoirs. the overpressured reservoirs of Es_3~3 subsection in Wendong region are probably the ones that have good physical properties. From homogenetic temperatures that obtained form the fluid inclusions in quartz overgrowth, we find that there were 4 episodes of fluid flows in Dongpu depression. In conjunction with the analysis of the burial history of overpressured reservoirs, we draw conclusions that the first, second and third episodes of fluid flows took place in the extensive rifting stage of Dongpu Depression, the burial depth when the first episode of fluid flow took place was about 1500m, the age was about 36 my; the burial depth of the second and third episodes of fluid flow was between 1800-3000m at that time, the age was between 35-28my. The fluid flows of the second, third, and fourth episodes were in close relation to the overpressure and maybe were the results of the episodic hydrofracturing of overpressured mudstones and shales. The episodic fluid flow of overpressured mudstones and shales probably facilitates the cementation of carbonate, which decreases the physical properties of overpressured reservoirs. The dolomites and ferrodolomites maybe the products of the episodic hydrofracturing of overpressured mudstones and shales.

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文章系统地阐述了大气有机酸的研究历史、现状和目前存在问题及可能取得研究进展的方法。低分子有机酸是大气中重要的微量挥发性有机碳组分,它们广泛存在于大气对流层中,对气候、环境和生态系统具有重要影响。长期以来,对大气有机酸的研究都是基于其含量的分析,尽管这一研究手段对有机酸的认识起到了推动作用,但含量的分析已越来越不能满足于当前人们对大气有机酸生物地球化学认识的需求。由于稳定同位素组成的示踪作用,近年来人们开始探索利用有机酸中碳同位素的测试分析方法来研究其循环过程。这一方法涉及水溶液中有机酸的萃取过程。由于其近发、半挥发性和其易污染性,常规的萃取方法不能应用于有机酸的萃取。最近出现的固相微萃取技术为有机酸碳同位素组成的准确分析研究提供了可能的途径。利用这一方法探索有机酸同位素组成的分析,有可能为大气有机酸生物地球化学循环研究开辟一片新的天地,从而使该领域研究向前推进一步.

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目的:调查贵州省燃煤型氟中毒地区的氟源。方法:测定3个典型氟中毒重病村的煤、拌煤粘土、煤饼、煤饼灰的含氟量;调查贵州省煤含氟量。结果:化落、马家庄、偏坡寨3个村子的煤氟分别为107.8、104.1、117.6mg/kg,拌煤粘土氟分别为6103.7、1900.5、2619.7mg/kg,煤饼氟分别为805.3、480.7、1713.6mg/kg,煤饼灰氟分别为639.6、332.5、841.7mg/kg;贵州省煤氟均值为115.5mg/kg.结论:氟源主要是拌煤粘土,其含氟量一般很高。

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MCM-22 zeolite films have been grown with layers vertical to the substrate under hydrothermal synthesis conditions, and characterized by X-ray diffraction and scanning electron microscopy.