电感耦合等离子体原子发射光谱法测定硅铝钡锶合金中锶

探讨了用电感耦合等离子体原子发射光谱法(ICP-AES)测定硅铝钡锶合金中锶元素的分析条件并建立了测定方法。样品用盐酸、硝酸和氢氟酸溶解, 硼酸除氟, 试液经过滤后, 选择强度较大、峰形较好、干扰小和稳定性好的421.5 nm谱线作为分析线进行测定。结果表明, 锶浓度在0.001～0.025 mg/mL范围内线性关系良好, 线性方程为I= 11 551.75 ρ+72 706 384, 相关系数R²=0.999 9。对硅铝钡锶合金标准样品进行测定, 锶的测定值与认定值基本一致。硅铝钡锶合金实际样品中锶测定结果的相对标准偏差(n=10)为0.067%, 加标回收率为106%。     

偶氮胂Ⅲ光度法测定钢中微量锶

微量锶的吸光光度法国内报导甚少。资料报导用偶氮肿Ⅲ吸光光度法测定碱土金属,方法选择性差。我们采用偶氮胂Ⅲ作锶的显色剂,研究了如何提高方法的选择性。提出了在钙、镁、锶、钡混合液中测定微量锶的方法。     

钢中微量锶的极谱法测定

钢中微量锶的测定,现有的方法是采用偶氮胂Ⅲ光度法,本文选择了四甲基碘化铵为支持电解质,示波极谱法测定较低浓度的锶,并应用于钢中微量锶的分析,取得了较好的效果。峰值电位:Ep=-2.15V(vs.SCE)。其检出限量为:0.5μg/ml,适用于测定钢中0.005～1％锶。     

钙锶氯化物体系中钙和锶的重量法分析

针对氯化钙氯化锶混合体系,探索出能够准确分析该体系中钙和锶含量的分析方法。首先,用碳酸盐重量法分别对氯化钙和氯化锶单盐溶液进行分析,能够获得比较准确的测定结果且确定了碳酸盐沉淀适宜的烘干温度和烘干时间分别为200 ℃和20 h。在此基础上,结合碳酸盐重量法和经典的氯化银重量法对氯化钙和氯化锶的混合溶液进行准确地分析,分别获得碳酸盐沉淀的总质量和总氯的物质的量,再通过联立方程组求解得到钙锶氯化物共存体系中各组分的含量。最后,将实验方法用于分析钙和锶物质的量之比YB(YB=nCa∶nSr)为49、9.4、0.98、0.10和0.030的氯化物体系中氯化钙和氯化锶的组分含量时,测定结果比较准确,绝对误差小于0.5%。     

铅铝合金中锶的测定

铅铝合金成份简单加进锶的含量将影响合金的性能,是必检的元素。应用容量法测定锶其分析手续繁杂,时间较长。我们采用了原子吸收分光光度法测定铅铝合金中的锶,用钙盐作抑制剂,并消除铝的干扰,其方法简便,缩短了分析时间。该法仅适用于铅铝合金锶的分析。 一、仪器及试剂 1.仪器 原子吸收分光光度仪:WFX—1 B型     

示波极谱法测定硅锶铁合金中的锶

本文根据锶和其他碱土金属峰值电位的差异,拟定了在钡、钙等离子存在下测定锶的方法。进行了支持电解质和乙醇的用量、底液的酸度、共存离子及其干扰等条件试验,找到了测定硅锶铁合金中锶的理想条件。此方法简便、快速,避免了分离碱土金属的繁锁手段。     

硅铁中锶的测定-EDTA容量法

本文介绍了含锶硅铁中锶的间接络合滴定法,详细进行了缓冲溶液、铜试剂、硫酸钾等试剂用量及有关条件试验。选择了较佳的测定条件。本文拟定的分析方法对硅铁中0.5～5％锶的测定,获得了满意结果。此方法简便、快速。     

原子吸收光度法测定铝合金中锶

对铝锶中间合金中锶的测定条件进行探讨，较系统研究了火焰状态、火焰位置、测定体系及干扰元素等对测定结果的影响。     

二溴对甲基偶氮磺光度法测定锶的研究与应用

研究了新显色剂二溴对甲基偶氮磺与锶的反应,建立了直接测定硅锶铁合金中锶含量的光度分析方法。在0.72 mol/L硫酸介质中,锶(与二溴对甲基偶氮磺形成蓝色络合物,最大吸收波长为626 nm,表观摩尔吸光系数为6.22×104;在25 mL溶液中,锶量在0~12μg范围内符合比尔定律,显色反应具有很好的选择性,主要共存离子均有较大允许量,可用于硅锶铁合金中锶的直接测定。     

铅锶中间合金中Pb,Sr的测定

本文研究了铅锶合金中铅，锶的测定方法。采用ＥＤＴＡ标准分别滴定铅量和铅锶合量，通过试验找出了最佳条件，具有简便，实用，精密度和准确度高等特点，适用于铅仂中间合金的分析测定。     

接触阴极法制取金属锶

本文用接触阴极在 SrCl_2-KCl 熔盐中进行了金属锶的电解。在电解试验的基础上,确定了在 SrCl_2-KCl 盐系中,用接触阴极制取锶的最佳工艺条件和锶电解的技术经济指标。从阴极上取下被熔盐结壳覆盖的锶棒,经在密闭充氩的容器中重熔铸锭,其纯度接近99％Sr。     

Thermodynamic characteristics of strontium and barium in dilute liquid alloys with tin

The changes in the partial molar thermodynamic characteristics of strontium and barium in binary alloys with tin are determined by the emf method in the temperature range 973?C1073 K. The changes in the partial molar enthalpies are found to agree satisfactorily with the data of calorimetric measurements. The activity coefficients of strontium and barium point to a strong interparticle interaction between the alloy components, which increases in going from strontium to barium.     

Structure and properties of hypoeutectic Al-Si-Mg alloys modified with pure strontium

Pure metallic strontium has been used as a modifier for A356.0 alloys, and the relationship between microstructure and mechanical properties has been established. It is shown that mechanical properties depend on both the cooling rate and the amount of strontium in the melt. The effect of other elements (Fe, Mg) on the microstructure of strontium modified Al-Si-Mg hypoeutectic alloys has been studied. The mechanical properties are adversely affected through the formation of intermetallic compounds caused by the presence of these elements.     

锗酸锶纳米线光催化降解罗丹明B的研究

以锗酸锶纳米线作为光催化材料,分析了光照时间、锗酸锶纳米线用量及罗丹明B浓度对锗酸锶纳米线光催化降解罗丹明B的影响。固体紫外漫散射光谱表明锗酸锶纳米线属于典型的半导体,禁带宽度为3.67eV。随着光照时间的增加,罗丹明B的降解率增加。罗丹明B的起始浓度为10mgL-1、锗酸锶纳米线用量为20mg及光照时间4h时,罗丹明B的降解率为72.39%。随着罗丹明B浓度的增加,其降解率降低至34.92%。     

Recycling of synaptic vesicles at the frog neuromuscular junction in the presence of strontium

In these experiments, we followed the exocytosis and endocytosis of synaptic vesicles with the vital dye FM1-43 and asked whether calcium is important for membrane retrieval at the frog neuromuscular junction. We replaced calcium with equimolar amounts of strontium and monitored the staining of recycling vesicles by inducing exocytosis with electrical stimulation. Trains of 2,400 (2 or 20 Hz) or 4,200 (20 Hz) pulses failed to induce FM1-43 internalization in the presence of strontium, but they did in the presence of calcium. This effect of strontium was not due to a decrease in exocytosis, because FM1-43 release was similar in the presence of calcium or strontium. The impairment in endocytosis, observed as inhibition of FM1-43 internalization, could be overcome by longer periods of stimulation (6,000 pulses at 2 or 20 Hz) in the presence of strontium (1.8 mM) or by increasing the extracellular concentration of strontium to 10 mM (2,400 action potentials at 20 Hz). It is suggested that endocytosis is dependent on calcium influx and that strontium is much less effective in replacing calcium for endocytosis than it is for exocytosis.     

Microalloying and modification of steel with natural materials and industrial waste

The use of natural materials and industrial waste in the microalloying and modification of steel is studied. The metallurgical properties of a natural barium–strontium modifier are investigated, and its influence on the melting point of reducing slag is assessed. The results show that its industrial use is very promising. Terra software is used to assess the reduction of barium and strontium from their oxides by silicon and aluminum. The action of barium and strontium on the metal quality is analyzed. The potential of vanadium converter slag in microalloying steel with vanadium is established. The effectiveness of carbon from molten steel in the reduction of vanadium is assessed. Industrial tests are in good agreement with the theoretical findings. Recommendations are made for the optimization of microalloying and modification. The use of the materials here investigated improves the economics of steel production and considerably enhances the quality of the steel produced. The prospects for expanded of use of natural materials and industrial waste are discussed.     

Modification of steel with barium and strontium

The modification of steel by natural materials containing barium and strontium is considered. Thermodynamic modeling of the reduction of barium and strontium by silicon and aluminum is undertaken. The influence of modification by barium and strontium on the structure and mechanical properties of the steel is studied. The results are employed in the production of 25Γ2C and Γ13 steel in arc furnaces at the casting shop of OAO EVRAZ ZSMK and also in the production of 35XΓCЛ, 30XΓCЛ, and 12HЛ2ΦX steel at OAO Yurginskii Mashinostroitel’nyi Zavod by two-slag technology. The results of industrial tests indicate that modification with barium and strontium affects the microstructure and nonmetallic inclusions; and increases the margin of structural strength of the steel, estimated in terms of the yield point, strength, and impact strength at positive and negative temperatures. To identify the presence of barium and strontium in the steel, its structure is analyzed by means of extraction replicas on a transmission electron-diffraction microscope. The presence of barium and strontium within the grains indicates their reaction with the metallic melt, which affects the structure of the metallic matrix.     

真空硅热还原法制备金属锶

采用真空硅热还原法制备了纯度达98%～99%的金属锶。研究了还原温度、保温时间、制团压力、硅铁过量系数、反应物粒度等对锶还原率的影响。结果表明,在下述最佳工艺条件下,即真空度在0～100Pa,硅铁过量30%,制团压力30MPa,还原温度1 250℃,保温2.5h,锶还原率可达57%,XRD和XRF分析表明,渣相主要物相为2SrO.SiO2和SrO.SiO2的混合物,且2SrO.SiO2占绝大部分。     

试论碳酸盐岩锶同位素的应用与研究进展

介绍锶及其同位素的地球化学特征及这些特征在碳酸盐岩中的指示意义,综述了近年来国内学者利用碳酸盐岩中锶同位素特征开展海相地层定年、物源示踪、沉积环境变化等方面的研究情况,最后作者针对目前研究存在的局限性,提出了自己的看法.