阳离子交换树脂微柱分离测定矿石中锆的研究

建立了HD-8阳离子交换树脂微色谱柱分离富集矿石中锆的方法。研究了上柱酸度、淋洗液、洗脱液、干扰离子等对锆的吸附性能的影响。结果表明,上柱最佳酸度0.5~2 mol/L HCl、淋洗液1 mol/L HCl、洗脱液1 mol/L H2SO4,锆的吸附与洗脱效果最好。选用邻氯苯基荧光酮为显色剂,直接在硫酸介质中显色,胶束增溶光度法测定,操作简便,灵敏度高,选择性好。树脂的吸附容量为81.4 mg/g。与常规柱相比,微色谱柱吸附后,洗脱体积减少了16倍,柱效高,分离速度快,试剂用量少,灵敏度高。该方法可以用于实际矿石的分离测定,经标准值验证,测定值与标准值相近,多次平行测定后,方法的相对标准偏差为1.9%~2.7%,说明此法可用于分析实际样品。     

膜电解法处理含镍废水的研究

镍作为合金化元素得到广泛应用,不锈钢占全球镍消费量的大约一半,因价格昂贵,故镍的回收有很大的意义.采用单阴膜电解法对含镍废水中的镍离子进行电沉积回收,研究膜种类、电流密度、温度、电解时间、搅拌速度等因素对镍离子去除效果.实验结果表明:在电流密度为60 A/m2,温度为40℃,pH为3.5,电解时间为5h,搅拌速度为300 r/min的条件下,镍离子去除率可达到85.3％,阴极电流效率为56.8％.     

Leader–member exchange and job performance: The effects of taking charge and organizational tenure

We theorized and tested the mechanisms by which leader–member exchange (LMX) quality is associated with job performance. The results obtained using 212 employee–supervisor pairs from eight Chinese companies indicated that LMX quality had an indirect and positive relationship with taking charge via psychological empowerment and had an indirect and positive relationship with job performance via taking charge. In addition, organizational tenure significantly moderated the relationship between taking charge and job performance, such that the positive effect of taking charge on job performance became weaker as organizational tenure increased. Furthermore, organizational tenure significantly moderated the indirect positive relationship between LMX quality and job performance via taking charge; the indirect effect became weaker as organizational tenure increased. These results suggest that organizations should encourage managers to develop high‐quality LMX with their subordinates, which may make them feel more empowered and engage in more taking charge, and result in better job performance. Copyright © 2014 John Wiley & Sons, Ltd.     

Understanding employee innovative behavior: Integrating the social network and leader–member exchange perspectives

By integrating social network theory and leader–member exchange (LMX) theory, we explore the effects of three types of social relationships on employee innovative behavior: weak ties outside the group, LMX, and strong ties within the group. The results from a sample in a high‐tech firm showed that LMX fully mediated the positive relationship between out‐group weak ties and innovative behavior. Furthermore, within‐group strong ties negatively moderated the second stage of this indirect relationship, such that LMX was positively and significantly related to innovative behavior only when the number of within‐group strong ties was low. The theoretical and practical implications of these findings are discussed. Copyright © 2015 John Wiley & Sons, Ltd.     

Air-soil exchange of organochlorine pesticides in a sealed chamber

So far little is known about air-soil exchange under any sealed circumstances (e.g., in plastic and glass sheds), which however has huge implications for the soil-air-plant pathways of persistent organic pollutants including organochlorine pesticides (OCPs). A newly designed passive air sampler was tested in a sealed chamber for measuring the vertical concentration profiles of gaseous phase OCPs (hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs)). Air was sampled at 5, 15, and 30 cm above ground level every 10th day during a 60-day period by deploying polyurethane foam cylinders housed in acrylonitrile butadiene styrene-covered cartridges. Concentrations and compositions of OCPs along the vertical sections indicated a clear relationship with proximity to the mixture of HCHs and DDTs which escapes from the soils. In addition, significant positive correlations were found between air temperatures and concentrations of HCHs and DDTs. These results indicated revolatilization and re-deposition being at or close to dynamic pseudo-equilibrium with the overlying air. The sampler used for addressing air-soil exchange of persistent organic pollutants in any sealed conditions is discussed.     

不同复苏方法对阴树脂复苏效果的影响研究

研究了直接酸洗复苏法、树脂转为氯型后酸洗复苏法、氯化钠转型后用次氯酸钠氧化复苏法、次氯酸钠氧化后用盐碱混液复苏法、双氧水氧化后用盐碱混液复苏法等五种不同的复苏方法对铁和有机物污染树脂复苏效果的影响。结果表明：复苏方法不同时，亚铁离子污染树脂的复苏效果和铁离子污染树脂的复苏效果是不相同的，同时可看出，双氧水氧化后盐碱混液复苏法复苏铁污染树脂的效果最好；五种不同的复苏方法对腐植酸污染的树脂都有较好的复苏效果，且复苏效果相差不大。     

Changes in susceptibility of beech (Fagus sylvatica) seedlings towards Phytophthora citricola under the influence of elevated atmospheric CO2 and nitrogen fertilization

The growth-differentiation balance hypothesis (GDBH) predicts changes in susceptibility of plants against herbivores with changing resource availability. In the presented study we tested the validity of the GDBH for trees infected with a root pathogen. For this purpose Fagus sylvatica seedlings grown under different atmospheric CO₂- and soil nitrogen regimes were infected with the root pathogen Phytophthora citricola. High nitrogen supply increased total biomass of beech regardless of the CO₂-treatment, whereas elevated CO₂ enhanced biomass only in the high nitrogen treatment. The responses of beech under the different growing regimes to the Phytophthora root infection were not in line with the predictions of the GDBH. Enhanced susceptibility of beech against P. citricola was found in seedlings grown under elevated CO₂ and low nitrogen supply. Fifteen months after inoculation these plants were characterized by enhanced water use efficiency, by altered root-shoot ratios, and by enhanced specific root tip densities.     

滤筒式除尘器的改进及在白云石除尘中的应用

反吹风袋式除尘器存在运行阻力高、滤袋寿命短、排放浓度高等缺点.论述了利用改进滤筒、增设导流装置等一系列技术措施,提高滤筒式除尘器技术性能,从而用滤筒除尘技术对反吹风除尘器进行改造达到节能减排的效果.     

滇池水环境治理的“调水”“活水”工程

3.40MaB P，沿普渡河断裂发育的普渡河和沿小江断裂发育的小江均汇入到昆明盆地，形成滇池，并产生厚达千米的堆积物。早更新世晚期，金沙江贯通，导致普渡河和小江均倒流汇入金沙江，从而滇池处在金沙江、珠江和红河三大水系的风口的位置，滇池的补给系数变小，换水周期增长。近几十年来，污染物的输入和积累，导致滇池水质急剧下降。因此滇池水环境的整治，除了减少污染物的输入外，建议在禄劝县引掌鸠河的水入螳螂川，并流入滇池。滇池的集水面积增加到16 066 km2，滇池的入湖地表径流量就增加到26.64×108 m3，换水周期减少到197.2 d。与此同时使滇池在昆明向北流出，污染物不再扩散到整个湖泊，这样便可较好地解决滇池污染，整治滇池的水环境。     

碳纳米管/羟基磷灰石复合材料对水体F-的去除研究

以碳纳米管（CNT）和羟基磷灰石（HAP）为原料,通过原位合成法制备碳纳米管/羟基磷灰石（CdH）复合材料.利用XRD、FTIR、SEM与氮气吸附-脱附等表征其结构形貌,并通过静态吸附实验考察CdH对氟离子（F^-）的吸附性能.结果表明,室温下,CdH对F^-的吸附容量为11.05mg/g,明显高于HAP（5.02mg/g）.吸附动力学模型、Weber-Morris方程、Langmuir和Freundlich方程拟合结果表明,F^-在CdH表面进行Langmuir单分子层吸附,其吸附过程符合准二级动力学方程,并且颗粒内部扩散起主要作用.pH值为6时有利于CdH对F^-的去除.此外,结合反应前后固样XPS分析可知CdH对F^-的吸附机制主要为离子交换作用.