基于自适应电流保护协同因子的区域后备保护算法

提出一种基于自适应电流保护协同因子的区域后备保护算法,首先将自适应电流保护动作值对故障判断的影响力定义为自适应电流保护效用度,并将其作为权重构建自适应电流保护协同度函数和协同度期望函数,再将自适应电流保护协同度函数与协同度期望函数的比值定义为自适应电流保护协同因子,然后通过自适应电流保护协同因子识别故障线路。算法引入了自适应电流保护判据结果,使该区域后备保护算法的信息源更加可靠,并能应对故障类型的变化。该算法对系统信息同步的要求较低,同时,在保护动作信息高位数缺失或错误的情况下,利用该算法仍能对故障进行准确判断。最后,通过天津某配电网以及IEEE 33节点系统实时数字仿真(RTDS)对该算法进行了验证。     

基于EXCEL的三等水准网严密平差

利用EXCEL矩阵的运算功能，进行三等水准网平差计算，并以柱形图的形式体现出水准网中各结点的协因数大小，能形象地体现出各结点精度的高低。同时结合本案例，指出测量平差教学中EXCEL平差计算的优点。     

重组肺炎克雷伯菌发酵联产3-羟基丙酸和1,3-丙二醇

对表达了高效醛脱氢酶的重组肺炎克雷伯氏菌以甘油为底物生产3-羟基丙酸和1,3-丙二醇的过程进行优化,将发酵过程中补料阶段甘油浓度分别控制为0~10, 10~20, 20~30 g/L,并分3次间歇性补加甘油. 结果表明,发酵过程中补料阶段控制甘油浓度在20~30 g/L,发酵26 h得到47.20 g/L 3-羟基丙酸和43.90 g/L 1,3-丙二醇;而间歇性补加甘油产物得率最高,发酵26 h时3-羟基丙酸和1,3-丙二醇相对甘油的得率分别为0.35和0.38 mol/mol. 3-羟基丙酸和1,3-丙二醇联产可实现辅因子烟酰胺腺嘌呤二核苷酸的再生平衡,从而提高碳回收率.     

Pentadecanedioic acid production from 15-hydroxypentadecanoic acid using an engineered biocatalyst with a co-factor regeneration system

α,ω-Dicarboxylic acids are valuable precursors in various chemical industries and have recently been produced using biotechnological methods to overcome the limitations of chemical synthesis. Nonanedioic acid, decanedioic acid, undecanedioic acid, and dodecanedioic acid have been produced at high concentrations from ω-hydroxycarboxylic acids using engineered biocatalysts. However, no study has been attempted on the efficient production of pentadecanedioic acid. Here, the production of pentadecanedioic acid from 15-hydroxypentadecanoic acid was carried out with alcohol dehydrogenases (ADHs), aldehyde dehydrogenases (ALDHs), and NAD(P)H oxidases, including NAD(P)H flavin oxidoreductase (NFO), that used a co-factor regeneration system, derived from several species and expressed in Escherichia coli. Among the enzymes, Kangiella koreensis ADH (KkADH), Geobacillus kaustophilus ALDH (GkALDH), and Deinococcus radiodurans NFO (DrNFO) were selected because they had the highest activity. E. coli expressing pRSF-DrNFO and pACYC-KkADH/GkALDH as the best distribution of three genes in two plasmids was used as a biocatalyst to produce pentadecanedioic acid. The optimal conditions for producing pentadecanedioic acid from 15-hydroxypentadecanoic acid by the biocatalyst were pH 8.0, 35°C, 5% (v/v) methanol, 40 g L⁻¹ cells, and 60 mM 15-hydroxypentadecanoic acid with agitation at 250 rpm. Under these optimized conditions, 57.4 mM pentadecanedioic acid was produced after 3 h, with a molar yield of 95.6% and a productivity of 19.1 mM h⁻¹. The molar yield and concentration of pentadecanedioic acid showed the highest values among the reported biotechnological production of pentadecanedioic acid.