IPv6过渡机制讨论

本文在简要地介绍Ngtrans工作组提出的大多数过渡机制的基础上，尝试对它们进行区分、分类，并对每一种过渡机制的优缺点进行分析。另外．还对这些机制的布置以及一部分支持这些机制的产品平台进行讨论。     

Peracetic acid pretreatment of sugarcane bagasse for enzymatic hydrolysis: a continued work

Previous work has shown that the enzymatic hydrolysis of sugarcane bagasse could be greatly enhanced by peracetic acid (PAA) pretreatment. There are several factors affecting the enzymatic digestibility of the biomass, including lignin and hemicelluloses content, cellulose crystallinity, acetyl group content, accessible surface area and so on. The objective of this work is to analyze the mechanism of the enhancement of enzymatic digestibility caused by PAA pretreatment. Delignification resulted in an increase of the surface area and reduction of the irreversible absorption of cellulase, which helped to increase the enzymatic digestibility. The Fourier transform infrared (FTIR) spectrum showed that the absorption peaks of aromatic skeletal vibrations were weakened or disappeared after PAA pretreatment. However, the infrared crystallization index (N.O'KI) was increased. X‐ray diffraction (XRD) analysis indicated that the crystallinity of PAA‐treated samples was increased owing to the partial removal of amorphous lignin and hemicelluloses and probable physical change of cellulose. The effect of acetyl group content on enzymatic digestibility is negligible compared with the degree of delignification and crystallinity. The results indicate that enhancement of enzymatic digestibility of sugarcane bagasse by PAA pretreatment is achieved mainly by delignification and an increase in the surface area and exposure of cellulose fibers. Copyright © 2008 Society of Chemical Industry     

Amtshaftung bei Bauführung im Hochwassergebiet; fehlerhafter Flächenwidmungsplan; Nachforschungspflichten der Gemeinde

Bestehen ausreichende Anhaltspunkte für die Hochwassergef?hrdung, ist die Gemeinde verpflichtet, sich durch Nachforschungen Gewissheit über das Vorliegen oder Nichtvorliegen eines Hochwasserabflussgebietes gem § 38 Abs 3 WRG zu verschaffen. Liegt ein solches vor, hat sie gem § 12 Abs 1 Z 2 krnt GplG dieses im Fl?chenwidmungsplan ersichtlich zu machen. Erteilt die Gemeinde eine Baubewilligung ohne diese von der Erteilung einer wasserrechtlichen Bewilligung abh?ngig zu machen, haftet sie für die Kosten der Bauführung, die bei gesetzes-konformer Vorgangsweise unterlassen worden w?re.     

Metathesis as a versatile tool in oleochemistry

Olefin metathesis, awarded with the Nobel Prize in Chemistry 2005 for Chauvin, Grubbs and Schrock, has emerged as a powerful tool for organic as well as polymer chemistry. In oleochemistry, this reaction is well known and has been applied for many decades. Examples include the functionalization of the double bonds of different oleochemicals or the (direct) polymerization of plant oils via metathesis. More recent developments, particularly the development of better and more robust catalysts, allow for highly efficient cross‐metathesis reactions opening new possibilities for the direct introduction of chemical functionalities. Within this contribution, the development of metathesis in oleochemistry will be discussed, covering self‐metathesis as well as more recent developments in the field of cross‐metathesis that lead to desired platform chemicals.     

Übergangene Nachbarn; Erlangung der Parteistellung; Sachlichkeitsgebot

Die Regelung über die Erlangung der Parteistellung übergangener Nachbarn durch Geltendmachung von Einwendungen bis l?ngstens drei Monate nach dem angezeigten Baubeginn ist wegen der Anknüpfung an einen untauglichen Zeitpunkt verfassungswidrig.     

单微乳液中制备Ag/TS-1及丙烯气相环氧化

采用N2H4还原含AgNO3的单微乳液制备了Ag／TS-1催化剂。TEM表征结果表明，Ag高度分散于TS-1之上。以H2、O2存在下的丙烯气相环氧化为探针反应，考察了Ag／TS-1的催化性能。结果表明，采用Ag／TS-1为催化剂，Ag的负载量为1％（质量分数，下同），823 K焙烧后，373 K下反应30 min时，丙烯转化率为1．69％，环氧丙烷（Propylene oxide，PO）选择性为93．2％。当Ag的负载量超过2％时，反应过程中生成大量的热，造成PO的选择性下降。采用Ag的负载量为8％的Ag／TS-1催化剂，消除热效应后，丙烯的转化率为2．46％．PO的选择性为79．2％。     

L-乳酸和聚乳酸的研究进展

综述了乳酸发酵和提取工艺以及聚乳酸的合成进展,分析了L-乳酸及合成聚乳酸两种产品的市场前景,对进一步的技术开发提出了建议。     

硫酸铈和磷酸处理对铌酸表面酸度及催化活性的影响

用硫酸铈和磷酸对固体铌酸进行了表面处理。表面酸度和TG DTA测定结果表明 ,与未处理的固体铌酸相比 ,处理后表面强酸量提高 3～ 5倍 ,耐受温度由 30 0℃提高到 5 0 0～ 6 0 0℃。用于催化酯化合成二甘醇二苯甲酸酯增塑剂 ,处理后固体铌酸的催化活性和重复使用寿命有明显提高。     

Effect of Y2O3, CeO2 on Sintering Properties of Si3N4 Ceramics

The effect of rare earth oxides Y203 or Ce02 on sintering properties of Si3N4 ceramics was studied and the mechanism of assisting action during sintering was analyzed. The results in dicate that the best sintering properties appear in Si3N4 ceramics with 5% Y203 or 8% CeO2. Secondary crystallites are formed at grain boundaries after heat treatment,which decreases the amount of glass phase and contributes to the improvement of high-temperature mechanical properties of silicon nitride.