Optimal Dearsenification Parameters of Gold Sulfide Concentrate with a High As Content

The gold sulfide concentrate with a high As content in Liangshan District, Sichuan Province, China, is a potentially important resource. This paper describes experiments of dearsenification of gold concentrate in a weakly reduced atmosphere in a rotary pipe furnace. The results showed that the optimal parameters were a temperature range of 650-700℃, 15%-16% CO2 of gas and a reaction time of 30-40 min. The removal rate of arsenic and sulfur was over 95% and 25%-28%, respectively. With further oxidization and roasting, residue sulfur in the roasted materials was dropped to below 4%, and the cyanide leaching recovery of gold was over 92%.

Chinese hair arsenic content background and its regional distribution

Some 1313 hair samples from about 200 sample sites are collected. These sites cover 103 counties with different types of natural conditions and are far from cities (towns) or polluted areas.The hair As contents are analysed by hydro-atomic fluorescence spetrophotometry and the data are calculated by SPSS. The results show that Chinese hair As contents are between 0.004 and 9.999 μu/g.The median is 0.56μg/g. The arithmetic mean is (0.927±1.213) μg/g and the geometric mean is 0.571 μg/g. There are no significant differences between sexes and ages. The results of Pelson X2 and Shapio-Wilk W tests show that the As content in the same physical geographical area has a logarithm normal distribution. Hair As contents in southern China are significantly higher than that in the northern.The geometric means are 0.2~0.4 μg/g in medium-temperate zone and 0.4~0.6 μg/g in warm-temperate zone. In north-subtropical zone the hair As geometric mean increase up to 0.767 μg/g and in medium-subtropical zone, south-subtropical zone and tropical zone, it is higher than 1.00 μg/g. There is no difference between areas in the same physical geographical zone. Hair As content in Qinghai-Tibet Plateau area is also lower (the geometric mean is 0.267 μg/g). The standard level of hair As content for determining chronic Arsenism areas in China is also discussed.

含氧气调包装对牦牛肉肉色稳定性的影响

探究在不同含氧气调包装方式中影响牦牛肉肉色稳定性的因素。以牦牛背最长肌为试验材料,采用真空包装为对照组,以O_2含量为40%、60%、80%,CO_2含量为60%、40%、20%的三种不同含氧气调包装组为试验组,在0~4℃的贮藏条件下,每隔4天,对各包装组中牦牛肉的肉色、肌红蛋白百分含量、硫代巴比妥酸值（TBA值）、乳酸脱氢酶活性（LDH活性）、还原型辅酶Ⅰ（NADH）含量及高铁肌红蛋白还原酶活性（MRA活性）进行测定。结果表明：与真空包装组相比,含氧气调包装组更利于良好肉色的形成。O_2含量为60%的气调包装组中牦牛肉的肉色稳定性最好,且LDH活性和NADH含量较高。根据指标间相关性分析得出,LDH活性和NADH含量与a＊值和OMb%呈显著正相关（P〈0.05）。因此,LDH活性和NADH含量是影响各包装组牦牛肉肉色稳定性的主要因素。

商标图像检索技术述评

对商标图像检索的三种技术 (类目检索、文本检索、基于内容检索 )加以介绍 ,并重点阐述采用基于内容技术实现对纯图像、图形商标检索的原理和主要方法 ,最后分析归纳了实践应用中检索商标图像的障碍及有待解决的问题。

复方水蛭合剂对大鼠局灶脑缺血损伤的影响及与补阳还五汤的对比

目的 :探讨复方水蛭合剂对脑缺血损伤的保护作用。方法 :检测大鼠大脑中动脉缺血后 6、2 4小时脑组织匀浆Na+ K+ ATP酶、脑含水量、MDA、NO的变化及复方水蛭合剂对其影响并与补阳还五汤比较。结果 :复方水蛭合剂、补阳还五汤能提高脑缺血损伤大鼠Na+ K+ ATP酶的活性、降低MDA、NO及脑含水量 ,复方水蛭合剂作用比补阳还五汤强。病理学检查复方水蛭合剂、补阳还五汤较均较轻 ,复方水蛭合剂组比补阳还五汤组损伤轻。结论 :复方水蛭合剂、补阳还五汤对缺血大鼠脑有保护作用 ,复方水蛭合剂比补阳还五汤作用强。

CBI教学理念在商务英语阅读与写作教学中的应用

商务英语阅读与商务英语写作是商务英语专业两门重要的课程,在培养高素质的英语经贸人才方面发挥着重要的作用。商务英语传统的教学方法过多地关注语言形式和写作规则而忽视了商务内容。而且,目前商务英语阅读和商务英语写作都是分开教学,忽视了两者之间的紧密联系,不利于系统教学的开展。以内容为基础的CBI教学理念对商务英语阅读与写作教学具有重要的指导意义。

贸易技术含量、偏向型技术进步与中国就业结构

本文首先对贸易技术含量如何通过偏向型技术进步影响就业技能结构的内在机理进行了模型分析,然后基于2000-2014年中国制造业的行业面板数据并采用工具变量两阶段最小二乘法实证检验了商品贸易技术含量升级对中国制造业就业技能结构变迁的影响。研究结果表明:出口技术含量升级和进口技术含量提高对中国制造业就业技能结构优化均产生了显著的正向促进作用,而且进口技术含量和外商直接投资还在一定程度上强化了出口技术含量对就业技能结构的正向效应,但是贸易技术含量升级对就业技能结构变迁的影响效应存在一定的行业异质性。本文为理解中国制造业就业结构变迁提供了一个新视角,对于经济新常态下如何促进产业结构优化升级也具有一定的启发意义。