混菌状态对新菌系产生VC前体KGA的影响

通过测定氧化葡萄糖酸杆菌产酸变化 ,研究了新菌系混菌状态对产酸的影响。结果显示 :新混菌体系中 ,种液KGA为4 1- 5 5mg ml,混合菌菌群氧化葡萄糖酸杆菌 掷孢酵母为 2 6 - 35 :1,混菌生物量达 0 4 6 - 0 6 0 (OD值 ) ,有利于二菌在发酵中相互协调 ,促进产酸 ,调节接种生物量可增加产酸速度 ,缩短产酸周期 ,但不影响最终产酸量

环丙烷衍生物在CD_3OD离子体系中的H/D交换反应

研究了环丙烷衍生物在CD3 OD离子体系中的H/D交换反应产物离子 [M +1]+ 、[M +2 ]+ 和[M +3]+ 的碰撞诱导碎裂 (CID)反应特征。实验结果表明这些产物离子是由反应物与试剂离子之间发生H/D交换反应生成的。获得了环丙烷衍生物结构中活泼氢位置及其数量的信息

Ultrasonic relaxation kinetics on fast deuteron transfer reaction

Propylamine has been selected to investigate the isotope effect of a fast deuteron transfer reaction by ultrasonic relaxation method. Ultrasonic absorption coefficients of propylamine in heavy water (D2O) at 25 degrees C in the concentration range from 0.0107 to 0.6300 mol dm(-3) have been measured by pulse and resonance methods over the frequency range from 0.8 to 220 MHz. A Debye-type single relaxation absorption has been observed in the solution. From the dependence of the ultrasonic relaxation parameters on the concentration and solution pH, the source of the observed relaxation has been attributed to a perturbation of the chemical equilibrium associated with the deuteron transfer reaction. The rate and equilibrium constants have been determined by the measurement of the deuteroxyl ion concentration dependence of the relaxation frequency. Also the standard volume change of the reaction has been determined from the concentration dependence of the maximum absorption per wavelength and the adiabatic compressibility has been calculated from the density and the sound velocity in the solution. These results have then been compared with those obtained for propylamine in light water (H2O). The forward rate constant is greater and the reverse rate constant is smaller in DO than in H2O. The standard volume change for deuteron transfer is greater than that for proton transfer reaction, and the adiabatic compressibility shows a similar trend. These data support an argument that there exists a stronger hydrogen bond in D2O than in H2O. The difference of the stability in the intermediate states, R-ND3+... OD- and R-NH3+... OH-, has also been considered from the results of the isotope effects.

SYNTHESIS AND CHARACTERIZATION OF POLY-ORTHO-METHYLANILINE WITH DIFFERENT DEGREES OF OXIDATION

Poly-ortho-methylanilines (POT) in three states fully oxidized, fully reduced and oxidized in varying degrees were synthesized by the reaction of common POT (C-POT) having nearly equal amounts of benzenediamine and quinonediimine units with iodine or phenyl-hydrazine, and the resulting polymers were characterized by IR, C-13-NMR, SEM and elemental analysis. The results showed that the quinonediimine unit in C-POT could be reduced by phenylhydrazine to the benzenediamine unit, forming the polymer with low OD (oxidation degree) or in a fully reduced state and that iodine-oxidation resulted in the increase of quinonediimine unit and decrease of benzenediamine unit. The solubility and flexibility of the formed polymers depend strongly on the amount of quinonediimine unit in it. It is necessary to reduce the content of quinonediimine structure unit in order to improve the solubility of aniline-class polymers.

Effects of photoperiod on growth, mortality and digestive enzymes in miiuy croaker larvae and juveniles

The growth, mortality and digestive enzymes (trypsin, amylase and lipase) in miiuy croaker Miichthys miiuy larvae and juveniles (2-53 dph) were investigated at four photoperiods: 24L:OD), 18L:6D, 12L:12D and OL:24D. Larvae could not feed at OL:24D and did not survive up to 7 dph. In the 24L:OD, 18L:6D, 12L:12D groups, photoperiod had not significant effects on the growth of the rniiuy croaker younger than 20 dph. However, their total length and specific growth rate (SGR) were significantly larger at 18L:6D and 24L:OD than 12L:12D after 20 dph. Photoperiod also affected the mortality of the first feeding larvae (5 dph). being apparently higher in 5 dph larvae at OL:24D (60%) than at other photopenods (20-27%), but no significant differences in mortality were found among other photoperiods. High mortality of the miiuy croaker in 12L:12D, 18L:6D and 24 L:OD groups mainly occurred from 5 (20-27%) to 11 dph (11-16%) and tended to decrease gradually from 15 dph onwards. Digestive enzymes activities in the rniiuy croaker larvae and juveniles had a similar change trend with age at all photoperiods. They underwent drastic changes with age. The specific activity of lipase was significantly higher at 18L:6D and 24L:0D than 12L:12D, but there were no significant differences in specific activities of either trypsin or amylase among photoperiods. With regard to the total length, SGR, survival and digestive enzyme activities, our findings suggested that the optimal light regime for the culture of miiuy croaker during the early life stage was 18L:6D. (C) 2008 Elsevier B.V. All rights reserved.

青海省春小麦收割后田间堆放期间产量与品质的变化

为了解青海省春小麦收割后田间堆放期间产量和品质的变化，选择近年育成的春小麦品种“高原205”（白粒，易穗发芽）、“高原115”（紫黑色小麦）、“高原448”（红粒）和“高原314”（白粒）以及曾为青海省主栽品种的“青春533”（红粒）为材料，收割后以农民常用的田间堆放方式进行堆放，每隔9d对其进行采样，测定产量、SDS沉淀值和降落数值的变化。结果表明，随着堆放时间的延长，收获产量逐步下降，平均产量从第1次采样（Od）时的504g／m^2减少到63d后的384g／m^2，收获产量平均值与取样时间直线回归F值为20．91，大于F0.01（6．90）；SDS沉淀值变化较小，F值为0．90，小于F0．05（2．13）；降落数值在取样时间点上差异极显著．F值等于46，72，大于F0.01（2．87）。高原205的降落数值一直呈现下降趋势，而高原448、高原115、高原314和青春533的变化是在O～18d间上升，然后下降。总体而言，田间堆放对收获产量和品质不利。

汉字微机数据库及其在东北电力系统中的应用

汉字微机数据库的最大缺点是速度太慢,因此难以实用化。本文提出了一种新的汉字检索方法——标志域法,解决了这个关键问题,使查找速度提高了近十倍;再采用单层连续提问等一系列措施,还可节省相当多的存储空间,扩大了微型机的应用范围。本数据库非常适合于“最终用户”使用,即使是不懂计算机的人,也能在一、两分钟内学会使用它。

The ion-molecule reaction after multiphoton ionization in the binary cluster of ammonia and methanol

The binary cluster (CH3OH)(n)(NH3)(m) was studied by using a multiphoton ionization time-of-flight mass spectrometer (MPI-TOFMS). The measured two series of protonated cluster ions: (CH3OH)(n)H+ and (CH3OH)(n)NH4+ (1 less than or equal to n less than or equal to 14) were attributed to the ion-molecule reaction in the binary cluster ions. The mixed cluster of CH3OD with ammonia was also studied. The results implied that the proton transfer probability from the OD group was larger than that from CH3 group. The ab initio calculation of the binary cluster was carried out at the HF/STO-3G and MP2/6-31G** levels of theory, and indicated that the latter process of the proton transfer must overcome a barrier of similar to 29 kcal/mol. (C) 1999 Elsevier Science B.V. All rights reserved.