1,6—二磷酸果糖制备研究：Ⅰ.菌种的筛选及培养条件

介绍了１,６－二磷酸果糖产生菌的筛选和最佳培养条件的确定,在所筛选的菌种中９５１８、９５１９号菌株均具较高的产１,６－二磷酸果糖酶系活力。其最佳培养条件为：培养温度２８℃,ｐＨ６．５。     

双曲型叶片的数控加工模型研究

给出双曲型点构成的叶片工作面的解析方程,并用主曲率方法给出了刀具参数、数控加工中的步长和行距的定量计算模型,最后用等螺距叶片工作面算例验证本文所供方法不但确保了叶片工作面造型精度,而且大大地提高了加工效率．     

不同结合剂对熔融石英窑具性能与析晶结构的影响

主要对熔融石英结构、不同结合剂结合的窑具性能和高温析晶结构进行研究．通过不同结合剂含量的性能比较,确定最佳配方（高铝结合剂最佳含量为３０％,粘土结合剂最佳含量为２０％）,高温烧成析晶结构（α－石英,α－方石英,莫来石）及其含量．     

Quantum chemical definition and calculation of oxidation number

A new quantum chemical definition of oxidation number is proposed, in the present paper, as a direct generalization of the corresponding classical definition. According to the proposed general definition, the oxidation number can be calculated by use of molecular orbital data and a population analysis method or by use of other quantum chemical methods. For the practical calculation, we present a corresponding concrete calculation procedure within the framework of the maximum overlap population principle, which is very simple and very easy to use. The calculated numerical results are, on the whole, in good agreement with chemists' intuitive concepts of chemical bonding.     

阿利新蓝的合成

阿利新蓝 (ＡｌｃｉａｎＢｌｕｅ)是一种从植物中提取出的天然物。于 1 944年由Ｈａｄｄｏｃｋ和Ｗｏｏｄ在实验室通过多次实验后所发现。它的水溶液呈天蓝色 ,着色性好而且吸光系数很大。又因它较好的水溶性。所以可以作为高效的生物染色剂[1,2 ] ,用于粘蛋白染色、细菌染色及聚酯、纤维素等人造和天然纤维的染料[3 ] 。基于它的重大应用前景和较高的商业价值 ,探索出一条合理的工业化合成路线就非常重要了。有关阿利新蓝的应用虽然有很多 ,但始终未见合成阿利新蓝的文献报道。在设计它的有机合成时必然涉及酞菁铜 (ＰｃＣｕ)的氯甲基化反…     

Cover Picture: Highly Regioselective Sequential 1,1‐Dihydrosilylation of Terminal Aliphatic Alkynes with Primary Silanes (Chin. J. Chem. 5/2019)

The cover picture shows that sequential 1,1‐dihydrosilylation of terminal aliphatic alkynes with primary silanes enabled by one earth‐abundant cobalt catalyst has been developed. This protocol is operationally simple using readily available aliphatic alkynes, including simple acetylene and complex drug derivative, for efficient access to valuable gem‐bis(dihydrosilyl)alkanes in highly regioselective and atom‐economic manners. Corresponding asymmetric transformations are achieved with excellent enantioselectivities. More details are discussed in the article by Lu et al. on page 457–461.

     

Pauling's criterion of bond strength and the relative bond lengths in molecule MLk

In this paper, the bond strengths, defined by Pauling, for a series of molecules in the type of ML_k have been calculated by using the generalized method obtained from the maximum overlap method in a preceding paper and by using Pauling's pair–defect–sum approximation. A number of geometrical bonding situations are investigated. It is demonstrated why a previous study purporting to use of Pauling's criterion of bond strength to find that the axial bonds in trigonal bipyramidal ML₅ are stronger than the equatorial bonds is incorrect. The results obtained from the two methods approach each other and are in good agreement with the experimental bond lengths, which show that Pauling's criterion is viable and that the pair–defect–sum approximation is indeed an excellent one that agrees with the maximum overlap method.     

A new poly(2-hydroxy-3-phenoxypropylacrylate, 4-hydroxybutyl acrylate, diethyl maleate) membrane controlled clonidine linear release in the transdermal drug delivery system

Oral clonidine, used as an antihypertensive, can result in some side effects such as dry mouth, drowsiness, dizziness and sedation; thus, clonidine transdermal drug delivery (TDD) was considered. Use of the controlled release membrane was one of the methods in TDD systems to regulate the permeation properties. A new type of copolymer membrane that controlled clonidine linear release in TDD system was synthesized by UV radiation. This membrane consisted of three monomers: 2-hydroxy-3-phenoxypropylacrylate, 4-hydroxybutyl acrylate and diethyl maleate. The membrane had both fine permeation properties and perfect physical properties when three monomers were in the weight ratio of 4:4:2; this type of membrane was chosen as an optimized membrane. It was found that the membrane controlled clonidine zero-order release, the permeation rates decreased with the thicknesses of membranes increasing, and the permeation rates were linearly dependent on the square root of the concentration of clonidine. Furthermore, the optimized membranes were characterized by FTIR, DSC and SEM.