表面活性剂对铬天青S光度法测定微量铝的影响

本实验对十六烷基三甲基溴化铵(CTMAB)、溴化十六烷基吡啶(CPB)、聚乙烯醇(PVA)和十二烷基硫酸钠(SLS)等4种表面活性剂以及CTMAB-SLS混合表面活性剂在吸收光谱、络合物组成、酸度、体系稳定性及工作曲线等方面对Al-铬天青S(CAS)显色体系的影响进行了研究。结果表明,几种络合体系中Al-CAS-CTMAB-SLS四元络合体系较适宜测定微量铝,该体系最大吸收波长在642 nm处,表观摩尔吸光系数为1.03×105L.mol-1.cm-1。25 mL显色溶液中Al3+的质量在0~10μg范围     

矿石与钢铁中痕量铝的测定——铜试剂沉淀分离-CAS-CTAB胶束增溶分光光度法

微量铝的比色分析,常用的有铬天青S、铬青R和铝试剂比色法等。这些比色法受pH值的影响较大,有色络合物不够稳定,测定条件苛刻,重现性较差。据资料介绍,在铝与某些酸性染料(如CAS、ECR)形成的二元络合物中,加入表面活性剂—长碳链季胺盐,形成三元络合物,能大大改善测定条件。我们在前人工作的基础上,用溴化十六烷基三甲基胺(简称CTAB)—铬天青S(简称CAS)作了矿石和钢铁中铝的测定条件     

铬天青S-CTMAB分光光度法测量痕量铝

铬天青S测定铝对形成二元络合物，重现性不理想，加入阳离子表面活性剂溴化十六烷基三甲基胺（CTMAB）后，形成三元络合物，在增色，增敏，增稳方面取得很好效果。     

溴邻苯三酚红一混合表面活性剂光度法测定微量铍

铬天青S(CAS)或埃铬青R(ECR)—表面活性剂光度法测定铍已有报道。作者在研究表面活性剂存在下Mg(Ⅱ)与溴邻苯三酚红(BPR)的显色反应时,发现Be(Ⅱ)在适当条件下有类似反应。实践证明:在pH7.8的硼砂缓冲液介质中,在氯化十六烷基吡啶(CPC)和乳化剂OP存在下,Be(Ⅱ)-BPR显色反应发生强烈的增敏作用,且_(max)=640nm,2=3.6×10~4,比相应的二元络合物最大波长仅红移20nm,但灵敏度提高约1000倍。0～20pgBe(Ⅱ)/50ml符合比尔定律。选择性也较好。用于合金和矿     

铬天青S光度法测定塑料薄膜镀铝厚度

采用铬天青S光度法测定镀铝薄膜中铝的含量,然后由铝的密度和单位薄膜面积的镀铝量计算出膜镀铝的厚度。研究了铝与铬天青S(CAS)的显色反应,结果表明,在pH 5.5的缓冲溶液中,铝离子与铬天青S(CAS)生成络合物,最大吸收波长为610 nm,表观摩尔吸光系数ε=3.89×10⁴ L·mol^-1·cm^-1。在优化条件下,铝的质量浓度在0.004～0.20 μg/mL与吸光度呈良好的线性关系,检测限为0.004 μg/mL。对塑料薄膜镀铝样品进行加标回收试验,测得铝的加标回收率在97%～102%之间。方法测定了塑料薄膜镀铝样品的镀铝厚度,测定结果的相对标准偏差(n=6)小于3%。     

混合胶束协同增敏光度法测定水中痕量铜

研究了溴化十六烷基三甲基铵(CTMAB)和乳化剂聚乙二醇辛基苯基醚(OP)组成的混合胶束对铬天青S与铜(Ⅱ)显色反应的增敏作用,建立了分光光度法测定水中痕量铜(Ⅱ)的新方法。结果表明:在pH 9.0的NaAc-Na2HPO4缓冲溶液介质中,铜(Ⅱ)与铬天青S,CTMAB,OP形成绿蓝色络合物,λmax=609 nm,表观摩尔吸光系数为9.85×104L.mol-1.cm-1。铜的质量浓度在0~1.2 mg/L范围内与吸光度呈良好的线性关系,相关系数为r=0.999 8,检出限为0.002 2μg/mL。应     

乙醇存在下以铬天青S、两性表面活性剂测定钛及钛合金中微量铝

铝—铬天青S—表面活性剂三元络合物用于光度分析已有不少报导。各种表面活性剂的引入对于提高反应的灵敏度,改善反应条件起到良好的作用。特别是两性表面活性剂的引入,不仅大大提高了反应的灵敏度,而且还具有较好的选择性,已用于合金钢中微量铝的分析。但是,由于钛对铝的显色反应有较严重的干扰,在很多测铝体系中钛的允许限量均很小,纯钛及钛合金     

聚乙二醇辛基苯基醚存在下用铬天青S测定精矿中的铝

近年来,对铝(Ⅲ)—铬天青 S—阳离子型表面活性剂体系分光光度性质已进行了详细研究,并广泛应用于测定岩石、矿物、金属及合金中微量铝.对于铝(Ⅲ)—铬天青 S—非离子型表面活性剂体系的分光光度性质则研究得较少.     

Tween 20增敏二甲酚橙分光光度法测定水中痕量铝

研究了表面活性剂吐温20(Tween 20)对二甲酚橙(XO)与铝显色反应的增敏作用,建立了分光光度法测定水中痕量铝的新方法。实验结果表明,在HAc-NaAc介质中,铝与二甲酚橙、吐温20反应生成的有色络合物,最大吸收波长为510nm,表观摩尔吸光系数ε为2.63×104L.mol-1.cm-1,铝的质量浓度在0~0.64μg/mL范围内与吸光度呈良好的线性关系,相关系数r=0.998 7,检出限为0.007 7μg/mL。方法应用于管网水和河水中铝的测定,相对标准偏差为1.2%~1.7%,回收率在97%~103%范围。     

铝-铬天青S-磷酸根-Tritonx-305四元络合物显色反应研究

西安地质学院李绍卿在研究中发现在pH5的乙酸—乙酸钠缓冲溶液中,铝与铬天青S、磷酸根、Tritonx-305非离子表面活性剂形成一种新的四元混配络合物(Al-CAS-PO_4~(3-)-Tritonx-305)。该混配络合物的最大吸收峰为650nm,灵敏度高于三元络合物。其表观摩尔吸收系数为1.3×10~(?)。当     

转炉炉壳热应力分析

根据实际转炉建立实体模型。以有限元为手段,考虑了炉衬和炉壳材料的物性参数随温度变化的特点和炉衬与炉壳之间膨胀间隙,计算了转炉炉壳在温度载荷和炉衬膨胀压力同时作用下的热应力。所得结果可为转炉炉壳设计提供依据。     

The effect of amount of possession of the trait of hostility on accuracy of perception of hostility in others.

Some theories of personality hold that an individual's perception of others is influenced by his own personality characteristics; more specifically, that a trait of low social value will be projected more into others, and that insight into the possession of these characteristics reduces this distortion. These 2 hypotheses were tested by having a group of college students rate each other (including themselves) on degree of friendliness or hostility. Agreement with group rating about self yielded the insight score. In general, the hypotheses were supported; the "friendly" Ss were most accurate in their perception of others, and insight was positively associated with accurate perception. From Psyc Abstracts 36:04:4HL16M. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of rates of infection of two methods of emergency ventricular drainage

The rates of infection of two methods of external ventricular drainage in use at Atkinson Morley's Hospital--namely, (a) percutaneous drainage with Rickham reservoirs and (b) tunnelled ventriculostomies--were compared in this retrospective review. Percutaneous drainage of CSF with Rickham reservoirs was associated with a 27% rate of infection as identified by positive microbiological cultures; tunnelled ventriculostomy catheters had a 10% infection rate. The difference in the infection rate between the two methods was statistically significant (P < 0.015). Other variables examined, including the age and sex of the patients and the reasons for ventricular drainage, were not associated with an increased rate of infection. Most infections from either method were caused by a coagulase negative staphylococcus. The average duration of ventricular drainage before identification of positive cultures was 5.7 days for Rickham reservoirs and 6.0 days for ventriculostomies.     

浅析《野草》的版画特征

鲁迅先生一生热爱美术作品,对版画中木刻兴趣尤甚.<野草>作为其"写心之作",亦呈现出一些与木刻版画一致的审美特征:一是具有木刻版画的色彩特征,多对比、多冷色,有阴郁的美感;二是具有木刻版画的力度特征,环境描写、人物刻画处处刀锋毕现,遒劲有力,有一种"力之美".     

四辊破碎机车刀架的改造

针对四辊破碎机车刀架车削中存在的几个问题,详细介绍了电动车刀架的结构和工作原理,建立主要设计参数的数学表达式,并进行适当的分析。改造后,这种电动车刀架运行平稳、可靠、方便、省力,取得了预期的效果。     

焦炭热性能指标意义浅析

通过对焦炭在高炉内的历程及其变化规律的剖析,阐述焦炭热性能指标的意义,形象地把焦炭在高炉内的损耗分为三部分(M1,M2,M3)。指出M2对焦比及焦炭价格有一定的指导作用。     

Results of treatment of cancer of the cardia

Cancer of the cardia is traditionally discussed with cardiac cancer of the lower portion of the esophagus and upper gastric cancer invading the esophagus, and the specific characteristics of cancer of the cardia have never been clearly defined. We reviewed the outcome of 172 patients with adenocarcinoma of the cardia who had undergone radical surgery between 1949 and 1994 in the Division of Gastrointestinal Surgery of the Cancer Institute Hospital. The centers of the tumors were located within 2 cm above and below the boundary between the esophagus and the stomach, and their longitudinal diameter was less than 8 cm. We divided the patients into an early period (1949-1979; n = 79) and a late period (1980-1994; n = 93), and focused on the historical transition. There were no differences in patient gender or histology between the two periods. However, the late period was associated with fewer cases of esophageal invasion and shorter longitudinal diameter, as the age of the population advanced. The number of advanced cancers such as the localized and infiltrative type had decreased, and early cancer and early clinical stage had become more common, but despite the fact that the number of early cancers had increased, extended dissection, such as thoracic and paraaortic lymph node dissection, was performed more frequently. By clinical stage, the long-term outcome markedly improved in Stage I patient in the late period, and tended to improve in Stage II and III patients. This appears to have been attributable to the prevention of micrometastasis by extended dissection, although the number of early cancers is another major potential cause. There were no differences in the outcome of Stage IV patients between the two periods, and further advances in multimodality therapy must be awaited. The range of resection is basically proximal gastrectomy, and if there are adequate indications, the prognosis is favorable. In view of the status of lymphatic flow and lymph node metastasis, and long-term results, lateroaortic lymph node dissection is important. Since the number of early cancer patients has been increasing, if intraabdominal recurrence is prevented, intrathoracic lymph node dissection will contribute greatly to the outcome of such patients.     

Comparison of the results of surgical and conservative treatment of fractures of the diaphysis of the tibia

In this paper is treated the fundamental problematic of the fracture of the diaphysis of the tibia and the therapeutic results after the conservative and operative treatment are confronted. Among 518 patients with 433 open fractures and 35 with closed fractures of the diaphysis of the tibia, successful treatment of more 2/3 was obtained in the period from 1968 to 1972. Following our casuistics and literature, whose results are similar, we find out that the average total treatment of the osteosynthesis of the fracture of the diaphysis was shortened for 2,5 months depending upon the type and the localisation of the fracture. Apolied methods of the operative and conservative and conservative treatment in relation to the velocity of the medical cure as well as to the extreme anatomical-functional results are analised. We noticed that osteosynthesis, made by the intermedullary nail and the extension of the canals or by a small AO table, by the achieved stability makes conditions of immediate motions and an early rehabilitation. Because of that it gives the best functional results.