测定钻井液中氯根含量的新方法

这里向大家推荐一种测定钻井液中氯根含量的新方法——硝酸汞法。用硝酸汞溶液作滴定剂,溴酚兰/二苯卡巴腙作指示剂,测定钻井液中的氯根含量,既简单,迅速,可靠,而且很精确(其精度与用传统的硝酸银法的精度对比见下表)。所以,可用该方法来取代目前使用的 API 标准硝酸银滴定法。用汞离子来滴定氯根是很理想的方法,其反应     

电絮凝法处理渭北油田污水的研究

采用电絮凝法对渭北油田污水进行处理,用铝极板作为组合电极,考察了电流强度、极板间距以及电解时间等因素对浊度去除效果的影响。结果表明,在电流强度为1.5A、电解时间为10min、极板间距为6cm时,油田污水的浊度显著降低,去浊率达到95%,除油率为97%,并且具有较好的杀菌效果。     

胶质与沥青质相互作用及对原油乳状液的影响研究进展

简要介绍了胶质、沥青质的化学结构特性,沉积机理和稳定分散机理,重点介绍了胶质与沥青质之间的相互作用及其对原油乳状液性能的影响。     

仙人掌多糖胶囊的制备

以仙人掌浓缩清汁为原料,进行仙人掌多糖的正交提取试验,并将提取的仙人掌多糖制备成多糖胶囊。正交提取实验结果表明,仙人掌汁浓缩5倍,乙醇与仙人掌汁的比例为1∶3,醇析温度为-18℃时,仙人掌多糖的提取得率最高;仙人掌多糖胶囊制备方法:以95%乙醇作为仙人掌多糖的黏合剂制粒,6%～8%HPMC溶于60%乙醇中作包衣液,在35～40℃下包衣,干燥2h后装胶囊,可获得品质较好的仙人掌多糖胶囊。     

Paenibacillus polymyxa purified bacteriocin to control Campylobacter jejuni in chickens

Campylobacter spp. cause numerous foodborne diseases. Poultry is thought to be a significant source of this zoonosis. Although many interventions designed to control this agent have been researched, none have succeeded. We evaluated a bacteriocin-based treatment to reduce Campylobacter jejuni colonization in poultry. A previously described purified bacteriocin (class IIa; molecular mass, 3,864 Da), secreted by Paenibacillus polymyxa NRRL-B-30509, was microencapsulated in polyvinylpyrrolidone, and 0.25 g of the purified bacteriocin was incorporated into 1 kg of chicken feed. One-day-old chickens were orally challenged and colonized with one of four isolates of C. jejuni, then reared in isolation facilities. Birds were provided ad libitum access to standard broiler starter feed and water for 7 days until 3 days before sampling, when only the treated groups of birds were provided the bacteriocin-emended feed described. In each of the eight (four by two replicates) trials, significant reductions in colonization by C. jejuni were observed (P < or = 0.05). As an example of this highly consistent data, in the first trial, 10 untreated 10-day-old chickens were colonized at a mean log 7.2 + 0.3 CFU/g of feces, whereas none of the 10 bacteriocin-treated 10-day-old chickens were colonized with detectable numbers of C. jejuni. Bacteriocin treatment dramatically reduced both intestinal levels and frequency of chicken colonization by C. jejuni. Feeding bacteriocins before poultry slaughter appears to provide control of C. jejuni to effectively reduce human exposure. This advance is directed toward on-farm control of pathogens, as opposed to the currently used chemical disinfection of contaminated carcasses.     

Bioaccumulation, biotransformation, and biochemical effects of brominated diphenyl ethers in juvenile lake trout (Salvelinus namaycush)

Juvenile lake trout (Salvelinus namaycush) were exposed to three dietary concentrations (0, approximately 2.5, and approximately 25 ng/g per BDE congener) of 13 BDE congeners (3-10 Br atoms) in the laboratory for 56 days, followed by 112 days of clean food, to examine bioaccumulation parameters and potential biochemical effects. The bioaccumulation of BDEs by the trout was highly influenced by biotransformation, via debromination, which resulted in bioaccumulation parameters that were much different than would be expected based on studies of chlorinated organic compounds (e.g., PCBs). Half-lives (t1/2's) for some BDE congeners (e.g., BDE-85 and -190) were much lower than expected based on their Kow, which was likely due to biotransformation, whereas t1/2's of other BDE congeners (e.g., BDE-66, -77, -153, and -154) were much longer than anticipated based on Kow. This was likely because the metabolites of BDE formed via debromination had the same chemical structure of these BDE congeners, which supplemented measured concentrations. The detection of three BDE congeners (an unknown penta, BDE-140, and an unknown hexa) in the fish that were not present in the food or in the control fish provide further evidence forthe debromination of BDEs. Half-lives of BDEs ranged from 38 +/- 9 to 346 +/- 173 days and biomagnification factors ranged from 1.6 (BDE-190) to 45.9 (BDE-100), but these bioaccumulation parameters need to be viewed with caution because they were highly influenced by debromination and relative abundance of individual BDEs that the fish were exposed to. CYP1A enzyme activity, measured as EROD, and free tri-iodothyronine (T3) concentrations in the plasma of lake trout varied significantly throughout the experiment but were not related to BDE exposure. In contrast, plasma levels of thyroxine levels (T4) were lower in both groups of PBDE-exposed fish compared with control fish after 56 days of exposure, and after 168 days in the high dose, suggesting that PBDEs may influence thyroid homeostasis at levels that are higher than what is normally found in the environment.     

高光谱图像技术检测枇杷叶片三萜酸含量及叶面分布

枇杷叶富含三萜酸类化合物,具有较高的药用价值。本研究首先建立枇杷叶高光谱信号与三萜酸含量的对应关系,然后利用高光谱图像包含每个像素点的光谱信号这一独特优势,检测枇杷叶片的三萜酸分布。通过联合区间偏最小二乘法(si PLS)建立三萜酸含量分析模型,结果表明,采用si PLS将全光谱均匀划分11个子区间,选择1、5、6、7联合,主因子数为4 h,建立的si PLS谱区筛选模型预测效果最佳,其交互验证均方根误差(RMSECV)和预测均方根误差(RMSEP)分别为3.392 mg/g和3.731 mg/g,校正集和预测集相关系数分别为0.8449和0.8223。根据si PLS模型计算叶片上所有像素点处的三萜酸含量,并通过伪彩色方法描述叶片中三萜酸含量的分布。研究结果表明,利用高光谱图像技术分析枇杷叶片三萜酸含量及叶面分布是可行的。     

半导体制冷技术在矿井照明灯具散热中的应用

阐述了LED技术与半导体制冷技术的基本特点,提出了半导体制冷热端散热的4种方式,并针对半导体制冷技术在矿井照明灯具散热中的应用方式进行了探讨应用效果分析。     

长沙DONE俱乐部

正本案位于长沙市中心区域,为城中新贵、潮人打造。从繁华街道进入酒吧前厅,经过特殊处理效果的腐铜格栅Logo墙,不复以往酒吧的庸俗之姿,奠定雅致艺术调性;以石材切割成特定造型拼接的地面与墙身,成本昂贵,细节讲究,于无声处塑造空间品质;左面的玻璃墙与喷绘彩画带来妩媚华美之感;整个前厅是