催化动力学光度法测定痕量锰的研究

在HA_c—N_aAc介质中,CPB对猛(11)催化高碘酸钾氧化甲基蓝的褪色反应有强烈的增敏作用,本文研究了影响其反应速度的最佳条件,建立了测定锰(11)的新催化光度法.方法线性范围为4×10~(-4)～8×10(-3)mg/L,检测下限为2.07×10~(-5)mg/L,可用于面粉和人尿中痕量猛的测定.     

案例结合任务教学模式在"软件蓝领"教学中的实践

基于以人为本的思想,在"软件蓝领"人才培养过程中采用案例结合任务的教学模式,以案例为基础"教",以任务为驱动"学",按照呈现案例、分析案例、学习新知识、分析任务、完成任务的步骤实施教学,可以激发学生学习兴趣,培养学生的合作精神和创造性思维。     

高等职业技术院校计算机专业教学的思考

文章列举了高职院校计算机专业教学与人才需求脱钩的现状，指出高职院校培养模式的改革趋势，高职院校的培养方向应定位于IT业“蓝领”；高职教师需积极应对。     

氯酸钾氧化酸性铬兰K催化光度法测定痕量钒

本文钒（V）在稀硫酸介质中催化酸性铬兰K与氯酸钾之间的褪色反应,建立了新的测定痕量钒的催化光度法。方法的测定范围为0～40ngV（v）/25ml,检测下限为2.47×10~(-12)g/ml。应用于水样和铝合金标样中钒的测定,结果令人满意。     

微乳液法制备光催化剂TiO_2

以TiCl4为原料,氨水为沉淀剂,采用微乳液法在十六烷基三甲基溴化铵(CTAB)/正丁醇/环己烷/水组成的微乳液体系中制备TiO2,并以亚甲基蓝为模型反应物评价光催化剂的性能。结果表明,当老化时间为12h,焙烧温度为500℃,TiO2用量为4g/L,光照时间为2h时,TiO2对亚甲基蓝(10mg/L)的降解率为71.2%。     

A note on Prussian blue in nineteenth-century Canton

Abstract

The use of Prussian blue in nineteenth-century Japan has been extensively researched, particularly in relation to the ‘blue revolution’ in ukiyo-e prints but its use by Chinese artists has not received the same degree of attention. A commodity traded by the East India Company, this pigment was used to ‘improve’ the colour of tea, but in or about 1825 the trade abruptly ceased. It now seems fairly clear that the cessation of the Prussian blue trade coincided with the setting up of a Prussian blue factory at the northern gate of Canton, and that knowledge of the industrial process was possibly acquired covertly from a London manufacturer. The pigment has been identified chemically among paint fragments collected during the dis-binding of an album of Chinese botanical watercolours sent from Canton to the Horticultural Society of London by tea inspector John Reeves between 1817 and 1830. This finding suggests that conservators should not exclude the possibility of finding Prussian blue on Chinese work dating from at least the early part of the nineteenth century.     

蓝牙技术在语言教学中的应用

蓝牙技术是无线通信领域中的先进的短距离传输技术,伴随着移动通信技术和无线网络技术的迅速发展,使用蓝牙技术的教学电子产品也得到了迅猛发展.蓝牙语言实验室利用该技术构建一种适合于无线校园网络教学的短距离传输方案,打破了传统语言教学的束缚,无需新添任何网络设备就可以构建一套完善的语言学习系统随时随地进行语言教学.     

Global blue carbon accumulation in tidal wetlands increases with climate change

Coastal tidal wetlands produce and accumulate significant amounts of organic carbon (C) that help to mitigate climate change. However, previous data limitations have prevented a robust evaluation of the global rates and mechanisms driving C accumulation. Here, we go beyond recent soil C stock estimates to reveal global tidal wetland C accumulation and predict changes under relative sea level rise, temperature and precipitation. We use data from literature study sites and our new observations spanning wide latitudinal gradients and 20 countries. Globally, tidal wetlands accumulate 53.65 (95%CI: 48.52–59.01) Tg C yr⁻¹, which is ∼30% of the organic C buried on the ocean floor. Modeling based on current climatic drivers and under projected emissions scenarios revealed a net increase in the global C accumulation by 2100. This rapid increase is driven by sea level rise in tidal marshes, and higher temperature and precipitation in mangroves. Countries with large areas of coastal wetlands, like Indonesia and Mexico, are more susceptible to tidal wetland C losses under climate change, while regions such as Australia, Brazil, the USA and China will experience a significant C accumulation increase under all projected scenarios.     

酸性铬蓝K褪色法测定水中的镁

在碱性介质中,二价镁离子与偶氮染料酸性铬蓝K相互作用形成离子缔合物,溶液的颜色由深蓝色变成了紫红色,最大褪色波长在581 nm处,另在504nm处产生吸收峰.考察了适宜的反应条件、光谱特征及方法的灵敏度与选择性.结果发现,镁离子在0~0.8μg.mL-1浓度范围内遵守比尔定律;该方法的灵敏度高(摩尔吸收系数ε为2.16×104L.mol-1.cm-1),选择性好,对大多数离子的允许量都较大.用于实际样品的测定,结果令人满意.据此建立了一种新的测定镁离子的方法.     

钼（VI）-溴酸钾-萘酚绿B体系动力学光度法测定痕量钼

在氨水介质中以氨三乙酸为活化剂,KBrO3氧化萘酚绿B的反应受Mo（VI）的催化而加速,据此建立了催化光度法测量痕量钼的新方法;选择了影响反应速率的最佳条件,测定了反应的表观活化能;方法的检出限为1．6×10^-9g/mL,线性范围为O～0．24μg/mL．用于水和食品中痕量钼的测定,获得满意结果．