双乙酸钠的合成和应用

双乙酸钠是一种高效低毒的化学防腐剂,性质稳定,成本低廉,用量仅为丙酸钙的30%～50%,对霉菌具有良好的抑制作用。本文对双乙酸钠的性质、应用和合成方法作了介绍。     

新型含氮阻燃环氧树脂的合成与性能

通过对羟基苯甲醛双缩对苯二胺席夫碱(AZ)与环氧氯丙烷在NaOH液中缩合,合成一种新型环氧树脂(DGEAZ).采用红外光谱(FT-IR)、核磁共振波谱(1H-NMR)、元素分析(EA)确定了物质的结构.通过示差扫描热分析(DSC)、热失重分析(TGA和UL 94V垂直燃烧测试分别考察了树脂的固化反应特性、热性能和阻燃性能.结果表明,该树脂具有和双酚A环氧树脂(DGEBA)相当的反应活性;固化后的树脂具有较高的成炭率(800℃,43.55%)和较好的阻燃性能(UL-94V-0级).     

负荷动特性综合方法研究

针对如何建立同类负荷动特性的综合模型问题,提出了基于实测响应空间的负荷动特性直接综合方法.该方法首先应用重心法确定同一类负荷特性的聚类中心,再通过对聚类中心等效样本进行参数辨识,以得到的模型参数作为该类负荷特性的综合模型参数.通过对某一变电站现场采集的负荷特性数据进行综合建模,结果表明该方法正确有效,而且其实现比综合辨识建模以及参数加权平均综合建模更为简便.     

煤气副产品制备酚醛树脂胶的初步研究

用生产煤气后的副产品制备酚醛树脂胶的方法，探讨其反应温度，反应时间，制备方案及生产工艺。     

Study on the Techniques of the Synthesis of P—Tolualdehyde from P—Xylene with Less Pollution

The indirect electro-synthesis of p-tolualdehyde was studied using Mn^3 /Mn^2 redox couple and Mn^2 was changes into Mn^3 on the Pb/Sb electrode. The effects of temperature,current density,electrolytic time on current efficiency,and the electrolytic and reaction conditions of oxidiazing p-xylene were also studied. The results showed that the yields of ptoluaidehyde were 74. 90% and the current recovery was 65. 50%. The reaction solution can be used repeatedly and no wastes were produced during the ptolualdehyde production process.     

乙酸异戊酯微型实验制备研究

分别用微型实验和常量实验制备乙酸异戊酯。实验结果表明，在醇酸摩尔比相同条件下，微型实验乙酸，异戊醇用量为常量实验用量的13％时，二者酯产率差异率为7．4％，可确定乙酸异戊酯微型制备中乙酸、异戊醇用量均为4．0mL，乙酸异戊酯平均产率62．7％。     

CAD中的机构分析与综合技巧

计算机辅助机构分析与综合(CAMA＆S)是一门新兴交叉学科,本文从模型的全面性、运算的简化性及公式的通用性等方面出发,运用工程中实际机构的例子,对CAD软件的编制进行了较为详细的探讨,更精炼地提出了一些编写CAD软件过程中值得注意的技巧,有较强的实用性。     

Enzyme activity changes during anthocyanin synthesis in ‘Olympia’ grape berries

Anthocyanin synthesis began in the skin of ‘Olympia’ (Vitis labruscana Bailey) grape when the berry growth reached a late stage in the second sigmoid growth-curve. During berry development, shikimate NADP oxidoreductase (SORase, EC.1.1.1.25), phenylalanine ammonia-lyase (PAL, EC.4.3.1.5), and chalcone flavanone isomerase (CHFI, EC.5.5.1.6) were investigated in the skin. These enzyme activities were high during early development of the young berry, but rapidly decreased thereafter, and were activated again when rapid anthocyanin synthesis subsequently occurred. When PAL from the young berry was analyzed by isoelectricfocusing polyacrylamide gel electrophoresis (IEF-PAGE), it showed a single activity band with a pI value of approximately 5.4, whereas PAL from the ripe berry showed two activity bands with pIs of 5.4 and 6.5. Thus, SORase, PAL, and CHFI seem to be involved in anthocyanin accumulation simultaneously, and newly synthesized isozyme of PAL may play a key role in pigment formation in ‘Olympia’ skin. The function of these enzyme activities in young berry is also discussed in this text.     

Changes in Starch Accumulation and Activity of Enzymes Associated with Starch Synthesis of Rice at Different N Supplying Dates

The changes in grain-filling, starch accumulation and activity of enzymes associated with starch synthesis in two different hybrid rice varieties were analyzed at different N supplying dates (earlier-date-emphasized, mean-date-emphasized and later-date-emphasized). The results showed that the N application of later-date-emphasized could promote grain-filling rate, increase grain weight and amylopectin content. The peak of activity in three enzymes of ADPglusoce pyriphosphorylase (ADPG), starch synthesis enzyme (SSS) and starch branching enzyme (SBE) in grains of two different rice varieties was not changed obviously, but the mean and maximum activity of these three enzymes changed, and the changes of SSS and ADPG were bigger than that of SBE as N supplying date changed. The N application of earlier-date-emphasized increased SSS activity and the N application of later-date-emphasized increased ADPG and SBE activities. The mean SSS activity during whole grain-filling period, and ADPG and SBE activities at middle and late period of grain-filling were significantly or very significantly correlated with grain-filling rate and accumulating rate of amylose and amylopectin. Both of ADPG and SBE played an equal important role in the changes of amylose and amylopectin content. The N application of later-date-emphasized increased amylose and amylopectin accumulating rate.