EDTA容量法测定铝锰合金中铝

采用氯化钠和氢氧化钠联合一次性沉淀锰、铁、钛等干扰元素,铝离子与EDTA络合后,用硫酸铜滴定氟盐取代释放的与铝络合的EDTA,测定铝锰合金中之铝.     

盐酸浸出赤泥回收铝的研究

研究了盐酸浸出拜耳法赤泥中铝的过程。考察浸出温度、浸出时间、液固比和酸度对铝浸出率的影响,并进行了赤泥回收铝的工业化试验。结果表明,影响铝浸出率的主次因素依次是浸出温度、液固比、盐酸浓度和浸出时间。赤泥在80℃下进行两段浸出,再经蒸发、除钛、除钙、中和及氢氧化钠溶液溶出,铝浸出率为88.13%,回收率为80.26%。     

偏硅酸钠溶液加压脱铝、钛的工艺研究

研究了高温加压条件下用CaO与CaCl2作混合脱杂剂,在偏硅酸钠溶液中脱铝、钛的工艺,实验表明,在温度130～150℃,压力0.8～0.9 MPa,反应时间2.0～2.5 h,CaO用量为3.0～4.0 g.L-1,CaCl2的用量为6.0～7.0 g.L-1时,铝的最高脱除率达97.00%,钛的最高脱除率达98.91%。对脱杂形成的铝钛渣的SEM图片分析,结果显示脱杂所形成的铝钛渣分子成排列紧密,分布均匀,结构稳定。这表明用CaO及CaCl2作混合脱杂剂脱铝、钛是可行的。     

钛合金中铝、钒连续络合滴定

本文试验了在pH5.3～5.8时用乳酸掩蔽钛,用过量的EDTA溶液在煮沸下络合铝和钒,以PAN为指示剂,用标准硫酸铜溶液滴定过量EDTA,由消耗的EDTA求得铝和钒合量。然后,加入氟化钠络合A1—EDTA中的铝,再以标准硫酸铜溶液滴定释放出的EDTA,求得铝量。并以差减法求出钒的含量。本法具有简单、快速、准确的优点。     

不同类别铝钛硼丝对高端铝排产品质量影响的研究

分析了两种不同进口铝钛硼丝的化学成分、晶粒细化效果和显微组织。同时分别用此两种铝钛硼丝作为晶粒细化剂,生产电子铝排用6063铝合金,对其后续产品质量进行跟踪分析,评估了这两种钛丝对铝排产品质量的影响。     

钛元素对铝钛合金中铝含量测定的干扰

在纯铝标样中加入相应的钛元素为标准,采用ＥＤＴＡ滴定法,测试钛元素对铝钛合金中铝含量测定的干扰。实验证明,钛对铝的测定干扰十分严重。文章给出了正确测定铝含量的方法。     

200kA铝电解槽添加二氧化钛制备铝钛母合金

论述了直接在预焙铝电解槽中生产铝钛合金的现状和意义.在200kA铝电解槽中直接添加二氧化钛生产含钛为0.3%～0.6%的铝钛母合金.对制备铝钛合金的工艺参数的选择、二氧化钛的添加方式的优化以及生产过程中对铝电解的电流效率等经济技术指标的影响进行了分析.结果表明：铝电解槽直接添加二氧化钛制备铝钛母合金工艺可行,经济效益显著.     

炉外法制取低铝钛铁的控铝方法

一、前言通常,钛铁中铝含量较高,一般在8—10%。在冶炼含钛不锈钢中,铝随钛铁一起进入钢水而使钢水增铝,钢中残余铝含量对钢表面及内在质量及各项性能指标有着较大的影响。为此,必须寻求满足不锈钢生产用的低铝钛铁。在北京钢铁研究总院、上海第三钢铁厂、上海铁合金厂、南京铁合金厂等单位大     

氟盐置换-EDTA滴定法测定铝锰钙合金中铝含量

试样以混合酸(盐酸∶硝酸∶水=1∶3∶5)溶解,在pH 6~7的六次甲基四胺溶液中使铁铝钛形成沉淀与钙锰等元素分离,用酸溶解沉淀,在强碱溶液中使铝与铁钛分离,以EDTA与滤液中的铝离子络合,用硫酸铜滴定过量的EDTA,然后用氟盐置换与铝络合的EDTA,再用硫酸铜滴定置换出的EDTA来计算铝锰钙合金中的铝含量。     

钒钛磁铁矿、钛精矿及钒钛高炉渣中钒的原子吸收测定

矿石及铁矿石中钒的原子吸收测定已有资料报道.它们用铝盐作干扰抑制剂,克服了一些元素对钒的干扰,但没有研究在大量钛存在下对钒的影响.本文以钒钛磁铁矿为试样,进一步对钛等主要组分和有关条件进行了试验,发现仅用铝盐抑制钛的干扰效果不好,当有高氯酸共存时,效果明显增加,可不分离钛直接测定钒.因钛精矿和钒钛高炉渣试样难于用酸分介完全,故用碱熔法,带入的大量钠离子显著增强钒的吸收信号,但加入铝盐和扣除钠的分子吸收后     

重庆高校推进产学研合作的案例分析

以重庆大学、重庆邮电大学和重庆理工大学为例,剖析重庆高校推进产学研合作的基本模式,已经取得的突出成绩,分析总结其基本经验.从完善政策法规体系、强化经济调控、建立组织机构、加强中介建设及开展国际产学研合作等方面,提出了深入推进重庆高校产学研合作的对策建议.     

Benzimidazole resistance in cyathostomes in horses in the Ukraine

The efficacy of treatment with cambendazole was tested in 1-year-old horses on a farm in Dubrovka, Ukraine. Thirty-five horses were treated. Their egg output was compared on the day of treatment and 14 days later with that of 33 untreated horses. Before treatment the mean number of eggs g-1 faeces was 614 in the controls and 766 in horses that had been treated. After 14 days the mean egg output in the controls was 580 and in the treated horses 369. This means a reduction of 54.5%. Only cyathostome larvae could be cultured from faeces collected after treatment. It can be concluded that benzimidazole resistance in cyathostomes is present in the Ukraine.     

Apoptosis in experimental myocardial infarction in situ and in the perfused heart in vitro

We report the appearance of apoptotic cells in experimental myocardial infarction (rabbit heart) in in situ and in vitro preparations. Apoptosis was recognized by intravital staining with Hoechst 33342 (Ho342), by nick-end labeling (TUNEL) and by DNA laddering. A steady rise in the relative number of apoptotic cardiomyocytes (apoptotic index) was noted in in situ preparations. Apoptosis was first noted 6 h after the onset of ischemia with its highest value occurring after 72 h. Apoptotic nuclei were absent in remote areas of the left and right ventricles. Apoptotic nuclei within the infarcted area showed diminished intensity of Ho342 fluorescence. Three days after ischemia, a border zone adjacent to the infarcted area consisting of apoptotic macrophages was recognized. A novel finding was the appearance of apoptotic cardiomyocytes in the isolated perfused ischemic heart. Occurring as early as 50 min after the onset of ischemia, a high apoptotic index was present adjacent to the ligature placed around the coronary artery. This observation provides the opportunity to selectively examine factors leading to apoptosis in the ischemic heart under controlled experimental conditions.     

Heatstroke in runners in Oklahoma

It is a common opinion that general surgery is the first step for whoever approaches a surgical discipline, and that whoever practices training in general surgery should learn the rudiments of each surgical branch. The role of microsurgery in the training of the general surgeon has not been well-established. Clinical applications of microsurgery in general surgery are few and are rarely required, and have been connected strictly to restricted indications. However, we think that microsurgery could be very useful to the general surgeon because it allows the execution of experimental research on rats, the only possibility permitted by law. In these studies the microsurgeon can perform many times and in a short time the same surgical operation, thus improving his skill, and easily getting familiarity with surgical instruments and sutures.     

Fractures in childhood in Khartoum

A prospective study of fractures in 231 children received at Khartoum North Teaching Hospital(KNTH) was carried out for a period of six months. The incidence of child fracture rated as one per day, then it increased from the age of 5 years onwards in boys and between 6 and 8 years in girls. Most injuries were sustained during the day time, especially between late afternoon and sunset. 82% of injured children presented to a medical facility, while 18% were taken to native healers first. Non-road traffic accidents accounted for 84% of the fractures mainly due to sports, domestic injuries and falls; whereas road traffic accidents were 16% and occurred mainly in pedestrians. Forty three percent of the fractures needed only first aid and splintage while 42% needed closed reduction. Thirty one percent of all patients were treated as inpatients. The long bones were affected in 91% of all fractures, the commonest site being the distal end of the forearm (26%), followed by supracondylar fracture of the humerus (15.6%). In the upper limb, left-sided fractures predominated. The epiphyseal injuries were 3.5% of all fractures, mainly at the distal radial epiphysis. Boys were commonly affected between 13-15 years of age. Open fractures constituted 9.8% of the series and were mainly due to traffic accidents in town dwellers, the most vulnerable bones were those of the leg and foot. Pathological fractures accounted for 2.2% and were due to bone cysts and osteogenesis imperfecta. The problem of child safety and the preventive measures need to be more stressed.