Stability of the Sarcin/Ricin domain of 28S RNA in rat ribosome under hydrostatic pressure

Under 2 100 bar of hydrostatic pressure, KNA N-glycosidase can still cleave the N-C bond of adenosine at position 4324 in R/S domain of 28S RNA in rat ribosome, demonstrating that high pressure has no effect on the tertiary structure of S/R domain.     

Kinetic model for the smectite to illite transformation in active geothermal systems

The smectite to illite transformation in active geothermal systems of New Zealand can be simulated by a first-order reaction kinetic model, which provides direct estimates about the minumum ages of active geothermal systems themselves. The derived kinetic values show that the smectite to illite transformation is sensitive to both temperature and time.     

Diamond synthesis from a system of chromium-carbide and Ni70Mn25Co5 alloy

In order to ascertain the mechanism of interaction between carbide and metallic catalyst and formation of diamond under high pressure and high temperature, and find a new method to synthesize diamond with special properties, it is necessary to investigate the reaction behavior of different carbides and metallic solvent_catalysts under high pressure and high temperature. A system of Cr-3C-2 powder and Ni 70Mn 25Co 5 alloy in weight ratio of 1∶6 was treated under 6 0 GPa and 1 500℃ for 20, 30 or 60 min respectively. X_ray diffraction of the samples indicated the Cr 3C 2 decomposed partially after high pressure and temperature treatment, and Cr 7C 3, Cr and diamond formed respectively. There was not any trace of graphite in the samples. The result suggested that the separated carbon atoms could form diamond directly without conversion process of graphite into diamond. The observation of SEI, WDX and EDX also showed that diamond crystals were synthesized in the system, which have perfect surfaces and shapes, with the average grain size of about 40 μm. The properties of the crystals are being investigated.     

用^1H—NMR测定纤维素的摩尔取代度

用＾１Ｈ－ＮＭＲ测定羟丙基纤维素的摩尔取代度,根据纤维素在ＤＣｌ中水解后的＾１Ｈ－ＮＭＲ谱峰面积来计算ＭＳ值。同时还应用铬酸氧化蒸馏法测定了羟丙基纤维素的ＭＳ值,以及利用ＭＳ与羟丙基含量的关系得到ＭＳ值,可以发现ＮＭＲ的方法是可行的。     

应变速率对8090Al-Li合金拉伸性能的影响

用动态拉伸的方法研究了应变速率对 80 90 Al— L i合金拉伸性能的影响 ,应变速率的范围为 10 - 3～ 10 3s- 1。结果表明 ,合金的强度和塑性随应变率的增加而增加。试样的 SEM和 TEM分析发现 :准静态下的断裂为沿晶断裂 ;随着应变率的增加 ,断裂从穿晶准解理断裂过渡到由显微空穴聚集而成的韧窝断裂。高应变率下80 90 Al- L i合金强度和塑性的提高与其变形机制和晶界无沉淀区 (PFZ)的变化有关     

大洋多金属结核中五氧化二磷分析方法

试样经ＮａＯＨ溶融,水浸取后,使Ｆｅ、Ｍｎ、Ｃｕ、Ｃｏ、Ｎｉ等共存元素形成氢氧化物沉淀与磷分离,滤液中的磷用磷钼黄光度法测定。方法简便、快速、精密度好、准确度高。经对标准物质ＧＢＷ０７２４９测定,结果与推荐值吻合,ＲＳＤ（ｎ＝１０）〈１．４％。     

Fe3Al合金的高温变形行为

用载荷松弛法对Ｆｅ－２８Ａｌ－２Ｔｉ合金在较高温度下的变形行为进行了研究．测定了Ｆｅ－２８Ａｌ－２Ｔｉ合金在高温变形时的载荷松弛曲线、应力减小因子Ｙ及激活能值,并对试样进行了显微结构观察．结果表明,Ｆｅ－２８Ａｌ－２Ｔｉ合金的高温变形是一个亚晶界吸收位错,而且不断向大角晶界转变的过程．     

关于国民收入随机模型的最小方差控制

通过对希克斯（Ｈｉｃｋｓ）一般模型的修正,建立一类关于国民收入的Ａｓｔｒｏｍ模型．由此讨论最小方差控制策略,同时结合我国实际问题进行计算、分析．     

灰胸竹鸡人工繁殖的研究

１９９５年１０月至１９９７年１０月对野生灰胸竹鸡（Ｂａｍｂｕｓｉｃｏｌａｔｈｏｒａｃｉｃａ）进行了人工繁殖的研究,结果为：产卵期４月下旬至７月下旬;卵的平均质量在（１５±２）ｇ之间;最佳孵化温度、相对湿度：１～１４ｄ内,温度为３８℃,相对湿度６５％～７０％;１５～１８ｄ内,温度降到３７℃,相对湿度７５％;雏鸟的生长模型为：ｍ＝２６２／（１＋ｅ２．６１－０．０３７ｔ）．     

链条锅炉模糊控制研究

针对链条锅炉的运行特点,提出一套基于模糊控制理论的链条锅炉控制方案。链条锅炉滞后时间长、惯性大,采用传统控制方法控制效果不理想,但采用模糊控制方法可以取得良好的控制效果。本控制系统由负荷控制和燃烧控制子系统构成。控制系统通过调节供入的燃料量和合理组织炉内燃烧,提高了锅炉的运行效率。针对不同的调节对象,分别设计了不同的模糊控制器,改善了控制系统的整体控制效果。该系统已经成功地应用于北京市德宝锅炉房。