171 resultados para High Pressure Die-cast
Resumo:
岩浆的分离结晶作用是岩浆演化的重要过程,与许多火成岩石的形成密切相关。自二十世纪50年代以来,采用实验手段研究岩浆的形成、演化一直受到地质学家的高度重视。 本文在0.5-2.0GPa、650-750℃和一定水含量条件下,以东准噶尔花岗闪长岩为初始物,进行了花岗闪长质岩浆结晶作用的实验研究。其结果可为东准噶尔地区A型花岗岩的成因提供一定的实验依据。通过对实验产物详细的岩相学观察和电子探针分析,获得以下主要认识: (1)熔体的含水量对矿物开始结晶的温度和晶出矿物的形状、颗粒大小有重要影响。相同时间内熔体含水量高时结晶出的矿物自形程度更好、粒度增大;随着熔体含水量的增加,斜长石的液相线温度降低;保持熔体含水量不变的情况下,随着压力的增加斜长石从熔体中结晶的温度降低。 (2)在压力为0.5GPa、熔体水饱和的条件下,花岗闪长质熔体中斜长石在675℃时开始结晶。结晶的斜长石与原岩的斜长石相比,其成分相对富钠长石而贫钙长石。在温度和熔体水含量一定的条件下,从花岗闪长质熔体中晶出的斜长石随着压力的增加,其钙长石组分增加。 (3)实验产物中的角闪石属于钙角闪石类,具体以普通角闪石为主。与初始花岗闪长岩的角闪石相比,实验产物的角闪石SiO2含量低,Fe3+很少。结晶形成的黑云母为铁叶云母,在2.0GPa压力时没有黑云母晶出而出现多硅白云母。 (4)花岗闪长质熔体发生矿物结晶后的残余熔体的成分受温度、压力和含水量的变化而变化。残余熔体中SiO2含量随着矿物从熔体中结晶程度的增加而升高。与无斜长石结晶的情况相比,有斜长石结晶时残余熔体的SiO2含量要高。在Na2O+K2O-CaO、FeO/(FeO+MgO)分别与SiO2的协变图中,残余熔体成分均落入A型花岗岩区,反映了它们与A型花岗岩在主量元素组成上的近似。因此,本文的实验证明,东准噶尔地区的A型花岗岩浆可以通过花岗闪长质岩浆发生角闪石、黑云母、斜长石的分离结晶作用形成。
Resumo:
该文从异常压力的成因和分布、异常压力的形成和演化、异常压力对天然气藏形成的作用以及超压带大然气藏形成的主控因素等方面进行研究.在流体力学和热力学研究构造抬升对异常高压的作用、库车坳陷古压力恢复、库车坳陷大气田形成与异常压力演化的关系及库车坳陷高压大气田形成的关键因素等方面取得了创新性成果.
Resumo:
岩石、矿物的弹性波速对地球的地震波速度进行物质成分和晶体结构的解释是十分关键的.该次论文工作的目的是在YJ-3000六面顶压机原有弹性波速测量技术的基础上建立一套P波和S波的弹性波速测量的新方法,可以在模拟地球上地幔的高温高压条件下获取物质的弹性参数.通过对超声学的基本概念的引入和超声测量基本技术的分析,特别是超声探头的采用,结合超声测量中透射法和反射法各自的优点,创造性提出了透射-反射联用的新方法.该方法的使用可以达到较高的走时测量精度,避免了温度和压力梯度对高温高压下弹性波波速测量的影响,同时还结束了多年来该压机上不能进行S波波速测量的历史.采用该方法在高压或同时高温高压下对不同的样品进行了弹性波速的测定,测量结果与前人相同样品的数据吻合得较好,表明了这种新方法的可行性和可靠性.
Resumo:
The enantioselective hydrogenation of ethyl pyruvate on the cinchonidine modified Pt/Al2O3 catalyst was investigated using a high-pressure reaction system with a fixed-bed reactor for the purpose to produce the,chiral product without separating the catalyst from the reaction system. The reaction was also investigated in a batch reactor for comparison. About 60% e. e. and 90% e. e. were obtained with the fixed-bed reactor and the batch reactor respectively, demonstrating the possibility for the heterogeneous asymmetric hydrogenation in the fixed-bed reactor. Some adsorbed chiral modifier, cinchonidine, can be slowly removed from the surface of Pt/Al2O3 under the continuous flow reaction, as a result, the e, e, values drops with the reaction time in the fixed-bed reactor. The enantio-selectivity is higher in the fixed-bed reactor, but lower in the batch reactor when ethanol was used as solvent than that when acetic acid as solvent. CO was used as molecular probe to characterize the adsorption of cinchonidine an the catalyst surface by IR spectroscopy, A red shift observed in IR spectra of coadsorbed CO with cinchonidine suggests that the cinchonidine adsorption is mainly through the pi -interaction with platinum surface and donating electron to the platinum surface.
Resumo:
The coadsorption of NO and O-2 on Ag(110) surface has been studied by X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS) and in situ Raman spectroscopy. The existence of oxygen enhances the adsorption of NO by forming the NOx species, that is, NO2 and NO3, and the NO in turn as a promotor facilitates the cleavage of the dioxygen bond, forming the surface atomic oxygen species having the same spectral characteristics as those produced using oxygen at high pressure. The oxygen species generated by the interaction is composed of two parts. One is produced directly by the decomposition of surface NO-O-2 complex at ca 625 K, which raised an O 1s feature at 530.5 eV and is absent at ca 800 K, while the another with an O 1s binding energy of 529.2 eV emerges at higher temperatures and shows similar properties as the reported gamma-state oxygen which bound tightly on restructured silver surface. The exposure to NO and O-2 causes noticeable changes in the morphology of the Ag(110) surface and the flat terraces superseded by small (ca 0.1 mu m) pits, and particles with typical diameters of a few micrometres were formed at elevated temperatures. (C) 1999 Elsevier Science B.V. All rights reserved.
Resumo:
2-Benzoxazolones or 2-benzimidazolones are synthesized in moderate to good yields in the presence of a base (KOH, NaOH, KOAc, NEt3, DBU) at atmospheric pressure or under a high pressure of CO by one-pot reductive carbonylation of 2-nitrophenols or 2-nitroanihne in the presence of selenium as catalyst. Besides the effect of base, the effects of solvent and temperature on the reaction were investigated at high or atmospheric pressure. Contrasting results were obtained for 2-benzoxazolones or 2-benzimidazolone at high and atmospheric pressures. Moreover, phase-transfer catalysis was exhibited. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005).