偶氮氯膦-Ⅲ分光光度法测定铋

研究了偶氮氯膦-Ⅲ(CPA-Ⅲ)分光光度法测定铋(Ⅲ)。在2.6mol/L高氯酸介质中及有表面活性剂聚乙烯醇存在条件下,铋(Ⅲ)与CPA-Ⅲ形成1∶2的紫红色配合物,该配合物的最大吸收波长为516nm,表观摩尔吸光系数ε_(516nm)=1.12×10~5 L·mol-1·cm-1,铋(Ⅲ)质量浓度在0~0.7μg/mL范围内符合比尔定律,方法检出限为0.27μg/mL。该方法已成功用于测定胃药中的铋。     

曙红B分光光度法测定痕量铋(Ⅲ)

在硫酸介质中,铋(Ⅲ)对碘酸钾氧化生物染料曙红B的褪色反应有强烈催化作用,据此建立了测定痕量铋(Ⅲ)的催化动力学方法。反应最优实验条件:在25 mL测定体积中,2.0×10-3mol/L曙红B用量为1.2 mL,1.0×10-2mol/L碘酸钾用量为1.5 mL,反应温度为90℃。在优化条件下,体系催化反应和非催化反应的吸光度变化值(ΔA)与铋(Ⅲ)质量浓度在0~0.18μg/mL范围内呈良好线性关系。方法检出限为8.04×10-7g/L,表观速率常数为2.97×10-4s-1,表观活化能为36.74 kJ/mol。对0.06 g/mL Bi(Ⅲ)标准溶液进行11次平行测定,其相对标准偏差为2.7%。本法已用于水体中痕量铋(Ⅲ)的测定,相对标准偏差(n=6)为2.8%~3.2%,与原子吸收光谱法进行了对照,结果一致。     

铋—檞皮素极谱络合吸附波测定锰盐中的痕量铋

在0.015至0.02mol/L H_2SO_4底液中,可获得灵敏的铋(Ⅲ)—檞皮素的络合吸附波.铋浓度由1.0×10~(-8)至6.0×10~(-6)mol/L与其二阶导数波有正比关系,检出限为5.0×10~(-9)mol/L.用其测定了试剂锰盐中10~(-4)的铋.测得电活性络合物组成为铋(Ⅲ):檞皮素=1:2,条件形成常数β=5.5×10~(-9).     

二溴硝基偶氮氯膦光度法测定铜合金中微量铋

本文研究了二溴硝基偶氮氯膦(D3NCPA)与铋的显色反应.在0.02～1.54mol/L HClO_4的酸度范围内,铋与该试剂形成组成比为1:2的紫红色络合物,最大吸收峰在620nm处,摩尔吸光系数为6,44×10~4.铋量在0～60μg/25ml范围内符合比尔定津,本法可测定铜合金中微量铋.     

1-[(2,3,4-三羟基苯)偶氮]-4-苯甲酸分光光度法测定铋的研究与应用

研究了1-[(2,3,4-三羟基苯)偶氮]-4-苯甲酸(TKAB)与铋的显色反应,试验了5种不同表面活性剂及1种混合表面活性剂的增敏作用,选定Bi(Ⅲ)-TKAB-CTMAB显色体系.该体系在pH1.45～2 80形成稳定的红棕色络合物,在445nm处有最大吸收,表观摩尔吸光系数ε=5.45 ×104.铋的质量浓度在0～20μg/10mL范围内符合比尔定律.用于铜合金中痕量铋的直接测定,结果满意.     

铋—7-碘-8-羟基喹啉-5-磺酸配合物吸附波的研究

本文提出了测定微量铋的铋—7-碘—8-羟基喹啉-5-磺酸新体系。在0.2mol/L NaOH,4×10~(-5)mol/L7-碘-8-羟基喹啉-5-磺酸溶液中,铋(Ⅲ)—7-碘-8-羟基喹啉-5-磺酸配合物在单扫示波极谱上有一灵敏的配合物吸附波。波的峰电位为-0.67V(vs.SCE),波高与铋浓度在8×10~(-10)～2×10~(-6)g/ml范围内呈良好的线性关系。对极谱波性质进行了初步探讨,将该体系应用于纯锡中痕量铋的测定,结果令人满意。     

多溴代不对称变色酸双偶氮类显色剂与铋显色反应的研究及分析应用

本文报道了四种不同的多溴代变色酸双偶氮类显色剂与Bi(Ⅲ)的显色反应.在高氯酸介质中,试剂与Bi(Ⅲ)形成稳定的蓝紫色配合物,反应的酸度范围宽,灵敏度高,尤以5-BPA-TB为最佳,其表观摩尔吸光系数达9.4×10~4,选择性亦好.用该方法测定了黄铜及紫铜样品中的痕量铋,与标准值符合,结果令人满意.     

铋(Ⅲ)-间硝基偶氮氯膦-溴化十六烷基吡啶-Triton X-100-乙醇显色体系的研究及其应用

本文研究了铋(Ⅲ)—间硝基偶氮氯膦—溴化十六烷基吡啶—Triton X-100—乙醇显色体系的光度特性,并确定了该体系中以铋配合物进行测定的最佳条件。该体系与相应的二元体系相比,灵敏度、稳定性和选择性均有显著提高,据此提出了测定铋的新方法。用于铅基合成试样中铋的测定,结果满意。     

遗传神经网络-分光光度法同时测定钢中铋和铈

应用遗传算法优化BP神经网络的结构和参数,解决了BP神经网络过拟合问题;建立一种遗传神经网络算法(GA-BP-ANN),用少量训练样本自适应概率搜索确定神经网络中隐含层结点数、学习速率(η)、动量因子(α)三者最佳匹配;在铋(铈)-二溴羧基偶氮胂同时测定显色体系中,应用遗传神经网络-分光光度法同时测定铋和铈,铋和铈络合物的表观摩尔吸光系数分别为8.3×104L.mol-1.cm-1和1.2×105L.mol-1.cm-1;25mL溶液中铋在0～25μg,铈在0～13μg服从比尔定律。方法用于钢中铋和铈的同     

铋(Ⅲ)-8-羟基喹哪啶体系极谱行为和表面活性剂增敏机理

本文在研究了铋(Ⅲ)—8-羟基喹哪啶(8-OXQ)体系极谱行为的基础上,详细研究了阴离子表面活性剂十二烷基苯磺酸钠(SDBS)对该体系示波极谱电流(ip)增敏机理。建立了测定高温合金中痕量(10~(-5)—10~(-4)％)铋的高灵敏新方法,检出限为0.4ng/ml(1.9×10~(-9)mol/L),结果可靠、满意。文中对比了Bi(Ⅲ)和8-羟基喹啉(8-OX)及其衍生物体系结合物峰电流以及Bi(Ⅲ),Pb(Ⅱ)-8-OXQ体系和Cu(Ⅱ),Cd(Ⅱ),Zn(Ⅱ)—乙二胺体系被SDBS增敏效应,然后提出     

Developing unit-specific credentialing

A systematic plan can streamline the certification process. A self-directed team identified, developed and implemented the components needed to make the workload manageable. The actual process for developing a unit-based credentialing system in a special care unit is described.     

Developing collaborative relationships

Most professionals want to work in a positive, supportive environment. In fact, most professionals spend more of their waking hours in the workplace than they do at home. A positive work environment is not only essential for physical and mental well-being, it's also critical in ensuring a healthy outcome for patients. Collaborative relationships in the workplace can create a collegial and friendly foundation from which practice can be developed.     

Developing Cross-Cultural Communication Skills

Engineers have traditionally focused on hard-skill knowledge acquisition, but the increasingly multicultural work practices of professional engineers now demand better soft-skill proficiency, such as foreign language ability, communication confidence, and cross-cultural experience. Students and staff within a university engineering department were surveyed to identify how cross-cultural language use potentially impacted academic and communication performance. The results indicate that engineering faculties may be concentrating on subject content at the expense of facilitating the development of soft skills. The findings suggest that students do experience problems with communication skills that may be exacerbated when studying in a second language. Lecturers need to become more energized to introduce innovative curriculum schemes, more proactive in developing challenging learning approaches, and more willing to integrate cross-cultural, language, and communication skills training into traditional engineering contexts. This case study has implications for any university engineering department where students are taught either partially or solely in a second language and where issues of communication and culture are recognized as impacting the professional development of engineers for the global workplace.     

Developing the reflective teacher

The conceptual issues and research findings surrounding the meaning and use of reflection are examined in this paper and serve as a foundation for discussing significant assumptions and beliefs regarding the use of reflection in nursing education. The strengths and limitations of reflection are discussed. The paper links current knowledge about reflection to the development of reflective thinking and its use by nurse educators and suggests strategies to enhance this development.     

莱钢H型钢的开发研制

简单介绍了莱钢热轧H型钢的生产工艺,主要设备,关键技术,产品试制要点,存在的问题和采取的措施。     

发展竞争优势

钨A电极的价格持续下跌,公司采取的策略是:持续发展机制优势、文化优势、成本优势等竞争优势,持续增强公司核心竞争力,通过竞争,不断扩大市场占有份额,赢得公司发展空间。     

Developing effective team leaders

For most staff, the most challenging leadership role they will play is their first. This chapter describes a research-based training program being developed to help these leaders increase their effectiveness in this first role.     

Developing mathematical knowledge.

Recent research has led to a significant reconceptualization of the nature of children's number knowledge development. This article outlines infants' and preschoolers' implicit protoquantitative reasoning schemas and shows how these combine with early counting knowledge to produce mathematical concepts of number. Research on elementary school children's informal and invented arithmetic is reviewed, and implications for mathematics education are evaluated. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

无障碍设计的发展趋势

无障碍设计是保证特殊群体方便生活的重要内容。文章从无障碍设计的重要性和迫切性、我国无障碍设计的现状等几方面进行了分析和探讨，提出了我国无障碍设计的发展趋势是：范围不断扩大，水平不断提高，层次不断细化。