Analysis of mineral composition of some Assam and Darjeeling black teas

Black teas manufactured in Darjeeling and Assam were analysed for various macrominerals such as P, K, Ca, Mg and microminerals such as Mn, Fe and Cu. A considerable amount of minerals, eg K (40-46 mg), Mg (2.7-3.0 mg), Ca (0.48-0.66 mg) and traces of Mn (0.28-0.40 mg), Fe (0.16-0.20 mg), P (29-41 μg) and Cu (12-22 μg) were found in a cup of black tea brew. Black teas manufactured from the leaf coming from a pruned section and fine portion usually showed higher mineral content than tea manufactured from unpruned sections and coarse grade teas of Darjeeling. Assam CTC tea was found to be richer in mineral content compared to Darjeeling orthodox tea.     

铜蒸气激光器的热设计

本文系统阐述了铜蒸气激光器的设计过程.在大量实验资料的基础上,给出了激光器放电管尺寸、输入功率密度的选择原则,通过分析放电管内气体温度分布、激光管径向热导损耗,建立了一套确定保温层厚度的方法.分析了光束"黑心"的原因,进而提出了解决途径.以上的设计思想在我们新近研制5W器件上得到验证.     

超声增容对大豆11S蛋白-刺槐豆胶冷致凝胶性质的影响

通过超声处理大豆11S蛋白-刺槐豆胶共混溶液,并随后添加葡萄糖酸内酯(GDL)冷致酸化制备刺槐豆胶增强大豆11S蛋白共混复合凝胶材料。结果表明,与对照样相比,经47.5 W功率超声强度处理4 min后,共混凝胶的强度有显著提高,且刺槐豆胶分散相所占孔隙率和平均孔隙直径分别降低了50.6%和34.6%。随超声处理功率的增加,孔隙率和孔隙直径进一步降低,表明有效改善了刺槐豆胶与大豆11S蛋白的相容性。共混凝胶强度随超声处理功率增加呈先增加后降低趋势,且超声处理样共混凝胶强度均大于对照样。     

大豆11S蛋白-刺槐豆胶冷致共混凝胶控释核黄素性能的研究

通过葡萄糖酸内酯(GDL)冷致诱导热变性大豆11S蛋白-刺槐豆胶(LBG)共混溶液形成凝胶,并对凝胶微结构、粘弹流变性、硬度性质、在模拟肠胃液中的溶胀性能及对核黄素的控释特性进行了分析研究。结果表明随多糖浓度的增加冷致凝胶微结构由蛋白连续相转变为多糖连续相形貌。添加多糖为0.05%~0.15%(m/V)范围时,伴随粘弹模量和硬度值呈增加趋势,随多糖量增加至0.25%(m/V)时凝胶硬度由峰值的46.7 g降低到38.2 g。凝胶弹性模量及硬度越大,随润涨时间延长,在模拟胃液中体积正向溶胀越大,而在模拟肠液中体积负向溶胀(即消减)愈小。荷载核黄素的共混凝胶在模拟胃液和肠液中的缓释性能与共混凝胶弹性模量及硬度值、微结构均一性及孔隙尺度呈正相关关系。     

四川盆地北缘下寒武统页岩生物标志化合物特征及其地质意义

针对四川盆地绵阳-长宁拉张槽北段米仓山地区下寒武统筇竹寺组黑色页岩开展了系统的有机地球化学分析,以正构烷烃、类异戊二烯烃、萜类化合物、甾类化合物等生物标志化合物为重点,探究绵阳-长宁拉张槽的成因机理及沉积环境。扬子板块北缘下寒武统黑色页岩中的有机质主要来自低等浮游生物与细菌的共同贡献;盐度一定的情况下,分层的海水不仅为水体表层浮游生物的繁殖发育提供良好环境,还给厌氧的喜盐细菌的繁殖提供了有利条件;筇竹寺组黑色页岩中检测出的4-甲基甾烷为典型热液喷口微生物的分子化石,其产出为绵阳-长宁拉张槽的拉张成因提供了证据。据此构建了该区古海洋模型,甲烷氧化菌、硫酸盐还原菌等热液喷口微生物,不仅为有机质提供了生物来源,还促进了浅部水体藻类的繁殖,提高了古生产力。     

微电网黑启动中考虑DG特性与线路投入顺序的串行恢复策略

制定合理的孤立微电网黑启动恢复策略对于加快微电网的恢复进程、减少事故损失具有重要意义。提出了一种适用于微电网黑启动的串行恢复策略。首先分析了分布式电源(Distributed Generation, DG)与大电网中传统火电机组所不同的特性,在此基础上建立了基于变异系数法的DG黑启动能力评估模型,并用于选取黑启动电源。然后以线路重要度和节点重要度作为网架重构的指标,建立了网架重构优化模型,并采用遗传算法进行求解。在求解出目标网架后,以单位时间内恢复发电量最大为目标,进一步确定线路的投入顺序。最后通过算例的分析及结果验证了所提方案的有效性。     

Fish Myosin Fragments Solubility and ANS-Fluorescence Intensity Affected by n-Butanol

Changes in the solubility and 8-anilino-1-napthalene sulfonate (ANS)-fluorescence intensity of oval filefish, tilapia, and black marlin myo-sins and their fragments by n-butanol were examined in connection with myosin gel-forming abilities. The thermal gel-forming abilities of myosins were greatly enhanced by the addition of 0.3–0.8M n-butanol. KC1 concentration-solubility curves revealed that after n-butanol addition a marked decrease in the solubility was observed for myosins and S-1s, whereas there was a slight decrease for rods. The fluorescence intensity of myosins-ANS in the presence of n-butanol increased markedly by heating at 30° and 35°C. A similar increase in the fluorescence intensity occurred in all S-ls-ANS, but not in rods.     

大豆蛋白酶法水解制取食用发泡剂的研究

为利用大豆蛋白制取食用发泡剂，比较了大豆分离蛋白和脱腥大豆蛋白粉水解前后的发泡性能。通过正文实验法，确定了以大豆分离蛋白为原料，酶法制取发泡剂的最佳工艺条件为：在浓度为５％的大豆蛋白中添加０．５％酶制剂反应１５ｍｉｎ。该工艺条件下所制得的发泡剂的发泡力可达（３９０±２）ｍｌ，且样品经减压干燥后仍能保持较好的发泡能力．     

Ex situ investigation of the proton exchange membrane chemical decomposition

The durability of Nafion^® polymer electrolyte membranes (PEMs) with potential application in PEM fuel cells has been investigated using accelerated durability tests to understand their degradation mechanism. After the attack by Fenton radicals, the Nafion^®111 membranes and the solution produced were collected for analysis. The existence of F ions in the solution indicated the chemical decomposition of the Nafion^® membranes during radical attacks. The F^- emission rate (FER) was about , corresponding to 0.024 wt% of F released from the membrane per hour. The NMR and FTIR spectrums demonstrated the polymer fragments mostly existed as whole side chains of the Nafion^® membrane. This result revealed that the degradation was originated from the decomposition of polymer main chain. Furthermore, the reflectance-FTIR revealed that the degradation of the PEMs was from the decomposition of the repeating units in the polymer main chains. With the increased loss of repeating units, small bubbles with the diameter of several microns started to form in Nafion^® membrane. These bubbles made the membrane vulnerable to hazards of gas crossover, which further led a catastrophic failure of the proton exchange membrane.     

豆粕中溶剂残留检测方法的研究

通过研究基准豆粕的制作方法和标样、样品前处理影响因素,建立一种能准确测定豆粕中溶剂残留量的方法。结果表明:制作基准豆粕时,加入适量水,有助于残留的有机溶剂充分挥发,得到合格的基准豆粕;标样结果稳定性与加水量关系不大,选择标样与样品的加热平衡温度均为120℃,加热平衡时间均为120 min,加水量均为200μL(3 g豆粕),样品重复性试验的精密度为0~4. 5%。对相同样品,采用本试验方法的测定结果较国标方法的高,更能准确反映豆粕的质量情况。