应用于景观水体异养硝化细菌的筛选鉴定及效果研究

[目的]研究景观水体的生物修复技术.[方法]采用SBR反应器,通过间歇曝气方式对底泥体系中好氧反硝化细菌进行了选择和富集,分离到1株异养硝化菌,并根据其生理生化性状和部分长度的16S rDNA序列确定了分离菌株的分类学和系统发育地位.[结果]从底泥中分离出1株异养硝化细菌SHW1,经过生理生化鉴定和16S rDNA测序.建立了系统发育树,鉴定出细菌SHW1属于Acineto-bacter sp..采用乙酸钠-氯化铵培养基培养细菌进行硝化特性研究,经过7 d好氧培养,NH<,4><'+>-N最终去除率为52.13%.并且具有产生NO<,2>-N的硝化性能.[结论]筛选出的异养硝化细菌SHW1在贫营养条件下对NH<,4>-N有较高的去除率,可以应用于景观水体脱氮.     

稀土负载生物炭的制备及其对低浓度氨氮的吸附特性

对微波/稀土元素铈吸附剂的制备条件及其吸附降解低浓度氨氮的反应条件进行优化,并采用XRD、SEM和FTIR对负载型吸附剂进行了表征。实验结果表明,负载型吸附剂内部结构发生变化,比表面积增大,羟基数量增多;负载后的生物炭对氨氮的处理效果明显优于原生物炭,其较为合适的制备条件为固液比(指原生物炭质量与氯化亚铈溶液体积之比,单位g/mL)1:25,浸渍pH 10;在氨氮溶液浓度为50 mg/L,初始pH为10,反应温度为50℃,反应时间为120 min,吸附剂投加量为5 g/L条件下,氨氮吸附量达到最大,为11.297 mg/g,且反应过程符合准二级动力学模型。      

Geochemical characteristics of rare earth elements and their implications for the Huachanggou gold deposit in Shaanxi Province, China

The Huachanggou gold deposit is located in the south part of the Mian-Lue suture zone in the Qinling orogenic belt. Rare earth element (REE) concentrations determined by ICP-MS are shown to characterize the ore samples and their wall rocks in three ore zones in order to reveal the origin of ore-forming materials and fluid. In AuI, REE chondrite normalized patterns of ore are similar to those of ore-controlling spilite; the ore-forming materials originated from deep magma, and magmatic activity offered main hydrothermal source for gold mineralization. The REE characteristics of AuII and AuIII are similar, and most of the ore samples are similar with the wall rocks. The ore-forming fluids of AuII and AuIII were metamorphic hydrothermal fluids which had extracted ore-forming materials part from the wall rocks, and part from the spilite in AuI.     

Acid leaching studies of chrysotile asbestos from mines in the Coalinga region of California and from Quebec and British Columbia

The dissolution of magnesium (Mg) and silicon (Si) from various samples of chrysotile asbestos was measured in N HCl at 25 degrees C. Nine samples were used, five from Canada and four from the Coalinga deposit in California. With milled samples from Quebec, the fraction of Mg dissolving was linearly related to the square root of the leaching time until at least 65% had dissolved. With a hand-picked sample of ore from Quebec, the sample from British Columbia and all the Californian samples, the Mg leaching patterns were sigmoid. The leaching patterns for Si were sigmoid in shape for all the materials tested. Mean Mg dissolution rates were calculated for each leaching period. Considerable differences were observed between samples from the different mining regions and also between hand-picked and milled samples from the same mine. Initially, Mg dissolved more rapidly from milled Quebec chrysotiles than from the Coalinga samples. This difference is due in part to the rapid dissolution of non-structural brucite, present in all the samples from Quebec but not in those from California. An additional cause is greater damage to the fibre surfaces resulting from the milling to which the less readily-opened fibres, typical of the Quebec mining area, were subjected. Once this readily-available Mg had dissolved, there was little difference in leaching rates between milled and unmilled samples from the different regions. When the fraction of Mg dissolving is plotted against that of Si, all the materials follow a similar pattern, suggesting that the dissolution of Si (as silica) is the rate-controlling step in the dissolution of Mg.     

五龙等金矿矿体数学特征及其研究意义

本文通过对五龙等几个金矿所做的金矿体的数学特征研究，即利用已开采的金矿脉的品位、厚度及空间位置等参数并进行数据处理，从而获得有关矿床的成因类型、形成机理及深部预测等信息。对今后矿山地质探矿特别是深部探矿具有一定的指导意义。     

电感耦合等离子体质谱法测定磷灰石中稀土元素分量和总量

基于电感耦合等离子体质谱法(ICP-MS)在稀土元素分析方面的优势,以HCl、HNO₃、HF和HClO₄溶解样品,控制He气流量为4.70 mL/min,实现了动能歧视碰撞池(KED)-ICP-MS对磷灰石样品中稀土元素分量和总量的测定。通过选择合适的同位素避免了质谱干扰;通过稀释基体质量浓度不大于0.25 mg/mL和选择45 ng/mL¹⁸⁵Re为内标进行校正相结合的方法消除了非质谱干扰。实验表明,在选定的实验条件下,各稀土元素在0～100 ng/mL范围内与其对应的质谱强度呈良好的线性关系,校准曲线相关系数r为0.999 0～0.999 9,方法检出限为0.000 1～0.019 2 ng/mL。将实验方法应用于磷灰石实际样品中稀土元素分量和总量的测定,所得结果的相对标准偏差(RSD,n=6)为1.1%～4.7%,加标回收率为96%～109%。     

电感耦合等离子体质谱法测定锆钛矿中16种稀土元素分量及其总量

锆钛矿中存在耐高温且硬度高的锆和钛,常规酸溶法难以将其完全分解,碱熔法处理样品时样品易粘埚。采用碳酸钠-硼酸熔融样品,以50 ng/mL¹⁸⁵Re为内标,动能歧视碰撞池(KED)模式和干扰系数校正法克服了轻稀土元素氧化物或氢氧化物对重稀土元素的干扰,建立了电感耦合等离子体质谱法(ICP-MS)测定锆钛矿中16种稀土元素(钪、钇、镧、铈、镨、钕、钐、铕、钆、铽、镝、钬、铒、铥、镱、镥)分量及其总量的分析方法。对比了盐酸-硝酸-氢氟酸-高氯酸敞开酸溶、硝酸-氢氟酸密闭酸溶、氢氟酸微波消解、过氧化钠-氢氧化钠熔融、硼砂熔融和碳酸钠-硼酸熔融6种分解方法,结果表明,碳酸钠-硼酸熔剂对样品分解的效果最佳。采用样品稀释法控制基体质量浓度为0.20 mg/mL和内标元素校正法降低基体效应。实验表明:各稀土元素的校准曲线线性相关系数在0.999 1~1.000 0之间,方法检出限为0.000 1~0.008 4 μg/g,定量限为0.000 5~0.042 0 μg/g。采用实验方法测定与锆钛矿成分类似的锆矿石标准样品中16种稀土元素分量及总量,结果与认定值基本一致。将实验方法应用于锆钛矿实际样品的测定,测定结果的相对标准偏差(RSD, n=8)为1.2%~4.0%,加标回收率为94%~110%,符合国家地质矿产行业标准DZ/T 0130—2006第3部分规定的加标回收率允许限90%~110%的范围。     

Targeted removal of the mu switch region from mouse hybridoma cells. A test of its role in gene expression in the endogenous IgH locus

The switch regions adjoining the DNA encoding the Ig heavy chain constant regions have been implicated in gene expression as well as isotype switching, in that transgenic mice express switch-containing transgenes at a level 100- to 1000-fold higher than the corresponding switch-deleted transgenes. To test whether the switch region of the natural IgH locus is also required for high level expression we have used homologous recombination to generate targeted recombinant hybridoma cell lines that lack the switch region sequences from the major intron of the mu gene. The expression pattern of these switch knock-out cell lines was compared with that of the parental cell line as well as to that of control recombinants using both steady-state mRNA level and nuclear run-on activity to assess heavy chain gene expression. In striking contrast with the results reported for transgenic animals, we have found only a minimal effect, if any, of deleting the switch element from the natural chromosomal location.     

硫酸铵对离子型稀土矿区土壤重金属的释放和形态转化影响

针对离子型稀土矿区浸矿过程导致的土壤氨氮、重金属复合污染问题,研究硫酸铵残留对土壤重金属迁移转化和形态的影响机制。通过土柱淋滤和室内土壤培养考察不同浓度浸矿剂输入土壤后,氨氮、重金属Zn、Cu和Cr的形态和迁移性变化。实验结果表明,与无浸矿剂淋滤对照组相比较,浸矿剂在重金属污染土壤中主要以氨氮形式存在,硝态氮占比低。在培养期间,浸矿剂硫酸铵淋滤降低了土壤pH值和土壤阳离子交换量（CEC）,重金属活性增加,当浸矿剂淋滤浓度为5%时,弱酸态Cr、Cu、Zn比例分别提高8.29%、5.21%、4.53%。研究结果表明：硫酸铵加剧了土壤酸化,提高重金属迁移性,促进重金属形态从生物不可利用态向可利用态转化。     

内蒙古中部典型花岗岩型稀有金属矿床特征和控矿因素

内蒙古是中国“三稀”资源（稀有、稀土、稀散）大省之一，其中铌（Nb₂O₅）、稀土储量位居中国之首.华北陆块北缘成矿区是典型的稀有～有色多金属成矿区，成矿作用与广泛发育的燕山期花岗质岩浆活动密切相关.内蒙古中部地处华北陆块北缘成矿区中段，以石灰窑和赵井沟2个花岗岩稀有金属矿床为研究对象，以摸清“三稀”典型矿床特征以及控制矿床形成和分布的有关因素为目的，以典型案例研究为方法，探讨研究区成矿背景、成矿特征、控矿等要素，推测在内蒙古中部地区可能存在稀有金属的区域性成矿作用.      

大兴安岭北部二十一站东地区地球物理特征及其找矿意义

大兴安岭地区植被茂密,地层露头较少,开展矿产普查难度较大。为了实现找矿突破,在研究区同时利用地面高精度磁法与激电中梯测量进行野外工作,通过野外测量数据与研究区物性参数的对照,最大限度地提取了与成矿有关的磁、电性特征,进而圈定磁、电异常。结合研究区地球化学异常,地表槽探查证揭露到金矿化蚀变带2条。通过地表查证情况,结合物化探异常特征,推测研究区具有较好成矿条件部位3处。