微波消解-石墨炉原子吸收法测定土壤中铊

通过研究土壤消解体系、混合基体改进剂的使用、石墨管类型的选择和标准加入定量过程对测定结果的影响,建立了适用于土壤中重金属铊的微波消解-平台石墨炉原子吸收方法。结果表明,使用HNO_3-HF-H_2O_2消解体系对土壤进行微波消解,石墨炉原子吸收测定过程采用Pd(NO_3)_2/Mg(NO_3)_2混合基体改进剂和平台石墨管,土壤中铊的检出限可达0.05 mg/kg,线性相关系数为0.996,加标回收率在95.0%~105.0%。使用该方法测得的结果与ICP-MS法比较,无统计学差异。改进后的方法具有简单快捷、灵敏度高、重现性好、线性范围广、结果准确等优势,易于推广使用。     

磷酸盐添加对快速好氧堆肥过程pH及腐熟效果的影响

随着我国环保政策的日趋严格,具有堆肥周期短、产品质量好、二次污染小等优点的反应器快速好氧堆肥工艺受到人们的广泛关注.然而,由于堆肥原料的有机物含量高,导致快速堆肥初期的有机酸累积,堆体pH偏低,影响堆肥效果.本研究拟通过添加磷酸盐,解决剩余污泥反应器快速堆肥过程出现的pH偏低问题.结果表明,添加磷酸盐可有效控制堆体pH,堆肥初期,HPO_4~-通过与有机酸解离产生的H~+反应生成H_2PO~-_4,提高堆体pH,堆肥后期,蛋白质降解产生较多NH~+_4,导致pH升高,堆体中的H_2PO~-_4通过与OH~-结合生成HPO_4~-,降低堆体pH.当HPO_4~-与H_2PO~-_4的摩尔比为2∶5时,堆体pH值可维持在6.0—8.5之间,有机物降解率最高,堆体的NH~+_4-N含量最大,达3.99 mg·g~(-1),堆肥过程的保氮效果较好,且所得堆肥产品的种子发芽指数也较高,腐熟程度良好.     

Toxicological assessment of TiO2 nanoparticles by recombinant Escherichia coli bacteria

Rapid and efficient methods to assess nanoparticle toxicity are desired in current research. Here we showed that Escherichia coli labeled by green fluorescent protein can be a good model bacterium for assessing acute toxicity of TiO(2) (about 50% inhibition ratios after 135 min exposure). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed that TiO(2) nanoparticles (NPs) can influence certain protein expression in the recombinant bacterium, and the obvious effects in repressed expression and elevated expression were observed in 30/40, 10/20 μg mL(-1) treated cells, respectively. However, the GFP expression (27 kD) was not influenced by introduced TiO(2) NPs. The change of the fluorescence intensity may be caused by the damage in folding and chromophore formation of the GFP post-translational modification due to generated reactive oxygen species. Furthermore, TiO(2) NPs at higher concentrations decreased their toxicity because of aggregation. 20 μg mL(-1) humic acid (HA) introduced to the medium can decrease the fluorescent inhibition owing to the barrier of steric hindrance it provides between NPs and cells.     

苯酚降解菌CM-HZX1菌株的分离、鉴定及降解性能研究

从污水处理厂的活性污泥中分离出一株以苯酚为唯一碳源生长的高效降解苯酚菌CM-HZX1.通过形态特征、生理生化及16S r DNA基因序列分析,初步鉴定菌株属于红球菌(Rhodococcus sp.),16S r DNA在Gene Bank的登录号为KM014567.实验结果表明,菌株CM-HZX1培养及降解苯酚的最适条件为p H=7.0,温度30℃,转速为150 r·min~(-1).该菌株能耐受4%的盐度,适应性强.0.5 g·L~(-1)苯酚在24 h时的降解率可达93.6%,1.5 g·L~(-1)苯酚在48 h时的降解率在90%以上.研究表明,该菌株在处理工业含酚废水方面具有广阔的应用前景.     

气相色谱法快速测定水中硝基苯类化合物研究

采用液液萃取前处理技术,利用二氯甲烷作为萃取剂,用FID检测器进行测定。该方法中,10种硝基苯类化合物在15 min内能够很好地分离,加标回收率为83．1％～106．2％。该方法简单、快捷、通用,且所用有机试剂毒性相对较低,具有较好的推广性与实用性。应用该方法对湘江和东江湖水中的硝基苯类化合物含量进行调查,表明该河流与湖库水质未受到硝基苯类化合物的污染。     

掘进工作面围岩散热的有限元计算

掘进工作面的围岩散热是至今尚未解决的一个重要问题。笔者根据掘进工作面围岩温度场的特点 ,分析了移动柱坐标下的导热微分方程 ,合理地确定了温度场边界、划分了单元格 ;推导了该特定导热微分方程的变分方程 ,阐述了有限元解算的原理 ;论述了由温度场解算结果计算围岩散热量的方法。由此原理和方法 ,编制了计算机程序 ,以一个简单的实例 ,分析了掘进工作面围岩温度场及其散热的特点和规律     

微波消解法测定工业水中的总铁含量

提出用微波消解、菲咯嗪－醋酸钠～醋酸为显色体系、以自制的铁含量测定仪测定工业水中的总铁含量，此方法省时，测定条件重复性好，测定值与电炉消解法一致。     

天津市地面沉降灾害及其防治工作

本文将天津市１９６６年到１９９２年共计２６ａ的精密水准资料，划分为７期，作出相应年代的地面沉降速率图，深入研究地面沉降灾害的特征，揭示了天津外环线以内市区地面沉降从６０年代开始出现至８０年代末，已发展到十分严重的地步。１９８５年以后天津市开展了地面沉降的防治工作以后，沉降灾害得到了明显的控制，显示了防治城市地质灾害的重要意义。     

一种野生香蘑的分离、鉴定、培养条件与产酶特性

为充分开发利用野生食用菌资源,从采集自北京怀柔的野生香蘑子实体中分离获得纯培养,编号为Lepista sp.GSM-11,结合形态学特征与ITS序列分析鉴定其分类学地位,并进一步研究其菌丝生长的最适碳源、氮源、C/N比、生长因子、最适温度和最适pH值,并测定了菌体液体发酵产漆酶、蛋白酶、植酸酶、核糖核酸酶和凝集素的特性,同时还研究了Cu2+对漆酶产量的影响.结果表明,该菌株与GenBank中报道的采集自中国辽宁、美国马里兰州和日本宫城的紫丁香蘑(Lepista nuda)同源性最高,分别为100%、99.98%和99.93%,确定该野生香蘑为紫丁香蘑(ITS序列GenBank登录号JQ519375);菌丝体生长的最适碳源为蔗糖,最适氮源为酵母浸膏,最适C/N比为20/1,最适生长因子为维生素C,最适温度为24℃,最适pH为7.0;GSM-11菌株菌丝体和发酵液中均具有漆酶活性,但缺乏其他3种酶和凝集素活性.1.0～2.0 mmol/L的Cu2+对漆酶分泌有显著的促进作用,其活性达到对照组的149.2%～196.4%.     

Experimental study on oxygen consumption rate of residual coal in goaf

In order to research the actual oxygen consumption rate of residual coal in goaf, the heating and oxidizing experiment was conducted respectively on five types of single particle size of coal samples and one hybrid particle size of coal samples by using self-developed CSC-B2 test system. This study measured inlet and outlet oxygen concentration of the oxidation tank, and calculated the oxygen consumption rate of each coal sample at different temperatures. For the residual coal in the same goaf, which is regarded as a hybrid particle size of coal consisting of a variety of single granularity of coal, its oxygen consumption rate is the mass weighted average of the rate of each particle size of coal. Accordingly, this paper established the equation of oxygen consumption rate of hybrid particle size of coal samples, taking into account temperature, granularity and oxygen concentration. Then comparison between the calculated value and the actually measured value of oxygen consumption rate of hybrid particle size of coal samples at different temperatures was conducted. And the results reveal that the calculated value basically coincide with the actually measured one. Moreover, the results prove that the established calculation formula for oxygen consumption rate can be used to accurately calculate the actual oxygen consumption rate of residual coal samples. The achievement of this research is of theoretical and practical significance for learning about the characteristics of coal spontaneous combustion and forecasting the self-ignition of residual coal in goaf.