由Na2O·nSiO2和Mg(NO3)2经沉淀法合成了三硅酸镁,用450℃煅烧或酸化方法对合成的样品进行改性.采用XRD、IR、TG/DTA和BET等表征手段,考察了原料加入顺序、酸化和煅烧过程对样品的结晶度和表面织构的影响规律,并对其影响机理进行了探讨.结果表明,不同滴定顺序和不同活化方法制得的样品均为非晶态物质.TG/DTA分析显示不同滴定顺序样品的组成相同.pH对样品的表面织构有明显的影响.BET分析表明,Mg(NO3)2滴加入泡花碱溶液合成的样品为微孔材料,以1~3nm和0.7~0.9nm的微孔为主,比表面积达568.93m2·g-1,水合硅酸镁含量较高.泡花碱滴加入Mg(NO3)2合成的样品为大孔材料,比表面积为179.40m2·g-1,水合硅酸镁含量降低.煅烧和酸处理增加样品的结晶度,减少样品比表面积,并改变样品的孔径分布.煅烧使中孔含量增加,形成中孔材料.酸处理使Mg2+被H+取代,表面形成硅羟基基团,材料以中孔为主

SOLUTIONS TO TEXT PROBLEMS 7.1 (c)Carbon-2 is a stereogenic center in 1-bromo-2-methylbutane, as it has four different substituents: H, CH, CH,CH2, and BrCH2. H BrCH2-C-CH2CH, CH3 (d) There are no stereogenic centers in2-romo-2- me. Br CH:-C-CH,CH3 CH, 7.(b) Carbon-2 is a stereogenic center in 1, 1, 2-trimethylcyclobutane

The packaging sector is an important global industry, representing about 2% of the Gross National Product (GNP) of the developed countries. The value of the packaging industry is about 345 million euros worldwide, of which Europe represents a third. Fifty per cent of this market is packaging for food. Forecasts suggest that the sector will continue to grow in size and importance Many cooking and preservation processes still largely depend on effective packaging, for example canning, aseptic, sous vide and baking processes. Processes such as drying and freezing would be lost without protective packaging after processing to control product exposure to the effects of oxygen light, water vapour, bacterial and other contaminants. However, modern food packaging no longer has just a passive role in protecting and marketing the product. It increasingly has an active role in processing, preservation

Ch. 4 Asymptotic Theory From the discussion of last Chapter it is obvious that determining the dis- tribution of h(X1, X2, . . Xr) is by no means a trival exercise. It turns out that more often than not we cannot determine the distribution exactly. Because of the importance of the problem, however, we are forced to develop approximations the subject of this Chapter

第二章化学动力学基础 2-1:按同一途径分解,表明正逆反应对应同一活化态…AHm=E正=Ean=459mol 2-4:(1)v=kc2(NO)C(O=0.018k(mol L-ls (2)24倍

Introduction By and large, I will follow OR, Chapters 1l and 12, so I will keep these notes to a minimum. J Games with observed actions and payoff uncertainty Not all dynamic models of strategic interaction fit within the category of games with observed actions we have developed in the previous lectures. In particular, no allowance was made for payoff uncertainty

Need to study structural mechanics to design properly to prevent failure There is no doubt that any of the disciplines of Aeronautics and Astronautics can contribute to an accident -engine failure -etc. But, the vast majority of non-human induced accidents is due to structural

1 RSA In 1977, Ronald Rivest, Adi Shamir, and Leonard Adleman proposed a highly secure cryp- tosystem(called RSa)based on number theory. Despite decades of attack, no significant weakness has been found (Well, none that you and me would know.)Moreover, RSA has a major advantage over traditional codes: the sender and receiver of an encrypted

高能物理可观测量的计算公式: A=[+, 8K(s) (A,.) 在微扰计算和事例产生器过程中,在相空间中随机产生末态 出射粒子的四动量常常会出现困难。假定对于n粒子末态,它的 洛伦兹不变四动量记为P1Pn,对应的质量为mmn,则其洛仑 兹不变的相空间体积元表示为 d)=(2)no)(p) i=1=1(2元) 相空间体积元可按如下公式因子化

The software described in this document is furnished under license agreement. The software may be used or copied only under the terms of the license agreement. No part of this manual may be photocopied or repro- duced in any form without prior written consent from The Math Works. In FEDERAL ACQUiSITION to all acquisitions of the Program and Documentation by or for the federal