系数倍率双波长分光光度法同时测定钢样中的铝和铜的含量

建立用系数倍率双波长法同时测定钢样中铝和铜含量的方法。在p H6.0的盐酸和六次甲基四胺缓冲溶液中,Cu2+和Al3+与铬天青S(CAS)和十六烷基三甲基溴化铵(CTMAB)发生高灵敏的显色反应,形成三元胶束络合物。根据实验得到铝和铜的一元线性回归方程,铝的回归方程为A=0.004C+1.121;铜的回归方程为A=0.016C+1.018。     

依来铬氰蓝R光度法测定铝

依来铬氰蓝R(Solochrome CyanineR),作为铝的显色剂,在选择性和稳定性方面,都优于铬天青R和铬天青S,是光度法测定多种试样中铝的理想显色剂.无阳离子表面活性剂(CTMAB)时,配合物在535nm处有最大吸收,摩尔吸光系数为6.5×10~4,铝量在1～8μg/25ml范围内遵从比尔定律,配合物在24h内无变化;有CTMAB时,最大吸收移至590nm处,ε_(500)=1.2×10~5,0～2μgAl/25ml符合比尔定律,配合物至少稳定2h.     

混合表面活性剂增敏铬天青S分光光度法测定锌阳极板中痕量铝

以铬天青S(CAS)为显色剂,CTMAB和PVA组成的混合表面活性剂为增敏剂,采用分光光度法测定了锌阳极板中痕量铝含量。探讨了铝与铬天青(CAS)的反应和显色条件,着重考察了不同的表面活性剂对体系的增敏作用。结果表明,在溴化十六烷基三甲胺(CT-MAB)和聚乙烯醇(PVA)存在下和pH 6.6的乙酸铵-乙酸缓冲介质中,铝与CAS反应生成有色络合物,络合物的最大吸收波长位于629 nm处,表观摩尔吸光系数为1.46×105L.mol-1.cm-1,铝离子的质量浓度在0~400μg/L的范围内服从比尔定律。方     

分光光度法测定镍基物料中铝分析方法的研究

本文采用氢氧化镧为载体,在PH=10的氨性缓冲溶液中共沉淀富集分离铝,通过加入含有长碳链的有机表面活性剂CTMAB和OP,使其形成三元络合物,最大吸收波长红移为610nm,摩尔吸光系数为1.90×105,灵敏度增大了约5倍。结果表明,在微酸性介质中,在CTMAB、OP和抗坏血酸存在下,铝与铬天青S生成络合物,样品的RSD在2.88%～5.59%,加标回收率为95.0%～105.2%,测定结果令人满意。     

铬天青S分光光度法测定铅

利用铬天青S(CAS)在有溴化十六烷基三甲胺(CTMAB)存在下的0.5mol/L硝酸介质中可与Pb2+形成红褐色络合物的原理,建立一种新的测定铅的分光光度法。Pb2+-CAS络合物的最大吸收峰位于584nm,在该波长处,Pb2+质量浓度在0~0.8μg/mL范围内与吸光度呈良好线性关系,其回归方程为A=0.888 5ρ-0.002 4,表观摩尔吸收系数ε584nm=1.46×105 L/(mol·cm)。用该方法测定土豆和硝酸钠中的铅,结果满意。     

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%。     

离子液体双水相萃取分光光度法测定铜

建立了由亲水性离子液体四氟硼酸1-丁基-3-甲基咪唑([Bmim]BF4)和NaH2PO4形成的双水相体系萃取光度法测定铜的新方法。研究了离子液体用量、溶液酸度、铬天青S、盐的加入量对测定的影响及共存物质对Cu2+萃取测定的影响及消除。在pH 5.0~8.0范围内,离子液体双水相中铬天青S及Cu2+形成的络合物有较高的吸光度,络合比为3∶1,络合物最大吸收波长位于590 nm,表观摩尔吸光系数ε=5.16×104L.mol-1.cm-1,Cu2+量的线性范围为0~4.0μg/mL。方法用于铝合金标准样品中     

CTMAB—铬天青B分光光度法测定微量钛

本文研究了在CTMAB存在下、于pH1.5～2.8的盐酸—NaAc缓冲介质中,钛与铬天青B可形成水溶性配合物,在565nm处有最大吸收。络合物的组成比为Ti:CAB=1:2,0～7μg/25ml符合比尔定律,摩尔吸光系数等于8.13×10~4,应用于钢中微量Ti的测定得到良好效果。 一、试剂与仪器 铬天青B(CAB):0.1％水溶液(天津化学试剂一厂产品); CTMAB:0.5％水溶液;     

钪-铬天青B-溴化十六烷基三甲铵络合显色反应的研究

已有一些文献用分光光度法测定Sc(Ⅲ),但用铬天青B(CAB)与Sc(Ⅲ)的络合显色反应的研究文献似未见到。本文系统地研究了在溴化十六烷基三甲铵(CTMAB)存在下,Sc(Ⅲ)与CAB络合反应的条件,实验结果表明,在(CH_2)_8N_4-HCl的缓冲液(pH4.5)中,Sc(Ⅲ)与CAB和CTMAB形成绿色络合物λmax630nm,ε=1.28×10~5,Sc(Ⅲ)含量在0～6μg/25ml范围内符合比尔定律。用摩尔比法、连续变化法和斜率比法则得络合物组成为Sc:CAB:CTMAB=1:2:3,并用拟定     

萘相分光光度法测定原油中微量铜

以铬天青S为显色剂,采用萘相分光光度法测定原油中微量铜,并考察了样品灰化和测定条件。在650℃将样品灰化4.5 h以上,用HNO3溶解灰分中的铜,使干扰离子与铜分离。在650 nm波长处的表观摩尔吸光系数ε=7.93×104L.moL-1.cm-1,25 mL溶液中其线性范围为0~8μg。原油测定结果的相对标准偏差为1.90%,回收率为99.83%。     

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。     

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.     

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。     

Effect of antibiotics of chemotaxis of human leukocytes

The effect of 20 different antibiotics on chemotaxis by human neutrophils was studied. Human leukocytes incubated with chloramphenicol, rifampin, sodium fusidate, and tetracyclines in vitro showed markedly depressed migration. The mechanisms by which these antibiotics affect leukotaxis are discussed.