甘肃省西和县三洋坝金矿矿石特征及金的赋存状态

文章主要对三洋坝金矿矿石特征及金的赋存状态进行了论述,表明三洋坝金矿矿石类型为少硫化物蚀变岩型金矿石及少硫化物碳酸盐石英脉型金矿石,矿石构造简单,以浸染状构造为主,主要的矿石结构有角粒状、麦粒状结构、自形-它形细粒结构、自形粒状结构等.矿石中矿物组成比较简单.自然金主要赋存在少硫化物蚀变岩型金矿石中,自然金分布不均匀....     

甘肃省西和县四儿沟金矿床矿石特征及金的赋存状态

文章主要对四儿沟金矿矿石特征及金的赋存状态进行了论述,表明四儿沟金矿矿石类型为蚀变岩型金矿石;矿石结构构造主要为自形-半自形粒状结构、它形粒状结构、包含结构、假晶结构,细脉状、浸染状及星散状构造等。矿石中矿物组成比较简单。自然金主要赋存在蚀变岩型金矿石中,自然金分布不均匀。自然金的赋存状态有两种类型:粒间金和包裹金,以粒间金为主,包裹金较少。     

大兴安岭北部虎拉林金矿床矿石及金矿物特征

虎拉林金矿位于额尔古纳成矿带北段,属于与斑岩体有关的隐爆角砾岩型金矿。矿石中主要的金属矿物为黄铁矿、褐铁矿和黄铜矿,同时也是主要的载金矿物;非金属矿物主要为石英和长石。矿石的主要结构为自形—半自形—他形粒状、交代和包含;矿石的主要构造为浸染状、角砾状、脉状和团块状。金矿物以自然金为主,其次为银金矿,其形态以角粒状、尖角粒状、长角粒状和麦粒状等居多,以中细粒者常见,最大粒度为0.38 mm×0.42 mm×0.06 mm。金的赋存状态以粒间金为主,其次是裂隙金和包裹金。依据矿石中金矿物粒度和赋存状态特征,建议矿石的磨矿细度选择以10 μm为宜,并可采用重选—浮选法进行选矿。     

甘肃帐房沟金矿矿石特征

帐房沟金矿矿化蚀变以低温热液蚀变为特征,形成了以石英、方铅矿、辉银矿、毒砂等为主的矿石矿物组合,矿石结构以半自形晶和它形晶粒状为主,矿石构造主要为星散浸染状等。矿石中金均以自然金形式产出,以粗粒金为主,赋存状态以包裹金、石英硅酸盐金为主。     

新疆那拉提成矿带某金矿选矿工艺试验研究

新疆那拉提成矿带某金矿矿石结构主要为半自形—他形粒状结构,矿石中主要硫化物为黄铁矿,金主要以显微自然金形式存在。针对矿石性质特征,开展了尼尔森重选、全泥浸出和浮选探索试验。结果表明:相比尼尔森重选、全泥浸出工艺,浮选工艺适于处理该矿石,其闭路流程可获得金精矿金品位50.44 g/t、金回收率92.90%的良好指标。     

徐阳河金矿金赋存状态及成因探讨

文章对甘肃省两党县徐阳河金矿矿石中金的赋存状态及矿石特征进行了论述,徐阳河矿石结构构造较简单,属于单纯金矿石,黄铁矿是组成该金矿石的主要金属矿物,自然金主要为粒间金和裂隙金,金主要以板片状、星点状、细脉状、不规则状、枝杈状分布于黄铁矿中,呈稀疏侵染状细粒分布。矿体受特定层位和断裂控制,根据金矿床产出的大地构造环境、矿物共生特点等分析,认为徐阳河金矿为沉积-热液改造型金矿床。     

内蒙古脑包沟金矿床矿石特征及金的赋存状态研究

脑包沟金矿床是受韧性剪切带控制的中—低温热液矿床,金矿石主要为蚀变岩型,含少量石英脉型。矿石结构有交代结构、骸晶结构、网脉状结构、包含结构、结晶粒状结构,矿石构造主要为浸染状构造、脉状构造和块状构造。金呈独立的金矿物(主要为银金矿)产出,以裂隙金、包裹金、粒间金等形式嵌布于黄铁矿、石英、钾长石、钠长石、方铅矿、褐铁矿等主要载金矿物中,金矿物形态多样,粒度以微粒为主。     

俄罗斯马加丹州乌瓦利内金矿地质特征及成因探讨

马加丹州乌瓦利内金矿区域位置位于鄂霍次克-楚科奇成矿带的边缘,第聂伯河区域北部。矿石自然类型属含砷黄铁矿石英脉型和含砷石英脉角砾岩型。矿石工业类型为石英脉型。矿石组成简单,金矿物呈中细粒嵌布,矿石主要为自形、半自形、他形结构、压碎结构、填隙结构和包裹结构,块状、脉状、网脉状和侵染状构造。金矿体主要赋存于早白垩纪花岗斑岩中,矿体的围岩即为花岗斑岩,矿体与围岩的界线清楚,部分矿体与围岩为渐变关系。主要围岩蚀变有硅化、褐铁矿化、黄铁矿化、砷黄铁矿化、绿帘石化,碳酸盐化等。在构造破碎带中强硅化地段形成石英脉,单一石英脉金品位较低,复合叠加矿化金品位较高,尤其金品位的高低与金属硫化物多少有密切关系,特别是与石英脉中砷黄铁矿的分布有关。矿体规模较小,矿体中的夹石不多,对矿体的完整性局部产生一定影响。     

青海纳赤台金矿床地质特征与金矿物特征研究

纳赤台矿区位于东昆仑东段中部,大地构造位置处于昆中断裂带与昆南断裂带之间即东昆南复合拼贴带内。矿区出露地层主要为中一晚元古代的万保沟群,岩性主要为白云岩、灰岩及浅变质碎屑岩。该矿床的矿物组成比较简单,矿石结构主要有自形—半自形晶结构、它形粒状结构、揉皱结构;矿石构造主要有块状构造、浸染状构造、条带状构造;矿区的围岩蚀变主要有:黄铁矿化、毒砂化、碳酸盐化、硅化、褐铁矿化;纳赤台矿床中金的赋存状态主要为独立矿物,呈星点状孤立分布,粒度属于显微金。金矿物颗粒形态多呈蠕虫状、树枝状、港湾状等不规则状。该区金矿物的嵌布状态有两种:包裹金和裂隙金,以存在于含砷黄铁矿和毒砂颗粒内部的包裹金为主。     

嵩县东湾金矿床矿石特征及金的赋存状态

东湾金矿是构造蚀变岩型金矿床。运用光谱、化学分析及光片、薄片鉴定等研究手段发现,东湾金矿床矿石为少硫化物金矿石;金矿物主要为自然金,其次为银金矿;金主要以可见金和不可见金两种状态存在。可见金主要为细粒金、微细粒金,一般呈包裹金产出,包裹于黄铁矿中,少量为裂隙金、粒间金。自然金呈它形粒状,以角粒状为主。以上研究结果为本区矿石加工、选冶提供了重要参考资料。     

ICP-AES法测定铍铜合金中Be, Ni, Ti, Co, Fe, Al, Si, Mg和Pb

通过操作条件的试验研究，用基体匹配法校正基体干扰，并选择了最佳工作条件。样品加标回收率为96％～110％，方法快速、简便、可靠，适用于铍铜合金的快速检验。     

Regional mapping panels for chromosomes 3, 4, 5, 11, 15, 17, 18, and X

The erm family of 23S rRNA adenine-N6-methyltransferases confers resistance to all macrolide-lincosamide-streptograminB (MLS) antibiotics, but not all MLS antibiotics induce synthesis of Erm methyltransferase with equal efficiency in a given organism. The induction efficiency of a test panel of MLS antibiotics was studied by using two translational attenuator-lac reporter gene fusion constructs, one based on ermSV from Streptomyces viridochromogenes NRRL 2860 and the other based on ermC from Staphylococcus aureus RN2442. Four types of responses which were correlated with the macrolide ring size were seen, as follows: group 1, both ermSV and ermC were induced by the 14-membered-ring macrolides erythromycin, lankamycin, and matromycin, as well as by the lincosamide celesticetin; group 2, neither ermSV nor ermC was induced by the 12-membered-ring macrolide methymycin or by the lincosamide lincomycin or the streptogramin type B antibiotic ostreogrycin B; group 3, ermSV was selectively induced over ermC by the 16-membered-ring macrolides carbomycin, chalcomycin, cirramycin, kitasamycin, maridomycin, and tylosin; and group 4, ermC was selectively induced over ermSV by the 14-membered-ring macrolide megalomicin. These data suggest that the leader peptide determines the specificity of induction by different classes of MLS antibiotics and that for a given attenuator, a major factor which determines whether a given macrolide induces resistance is its size.     

铂饰品中Pt, Pd, Au, Ag, Cu, Ni, Zn, Fe的测定

试验研究建立了同一试料溶液连续、同时测定铂饰品中各成分的分析方法。主体Pt以氯铂酸铵称量法及火焰原子吸收光谱(FAAS)法或电感耦合等离子发射光谱(ICP-AES)法测定滤液中残留Pt进行补差而测定。主成分Pd,Au,Ag,Cu和焊料成分Ni,Zn,Fe以FAAS法或ICP-AES法测定。其方法回收率分别为:Pt99.9%~100%;Pd99.3%~99.7%;Au99.5%~l01.5%;Ag98.0%~100%;Cu97.7%~99.3%;Zn98.0%~99.0%;Ni94.0%~105%;Fe95.0%~99.0%。实际试样分析时,各成分质量分数之和一般在99.12%~l01.2%之间,接近于100%,间接说明方法的可靠性。本法适用于Pt-Pd二元体系和Pt-Pd-Au-Cu多元复杂体系的铂饰品的破坏分析,可用于校正X荧光光谱法无损检测铂饰品的分析结果。     

稀土金属中14种非稀土杂质的ICP-MS法同时测定

本文研究了用 ICP- MS仪器同时测定稀土金属中 Mg、Al、Ti、Cr、Mo、Mn、Co、Ni、Cu、Zn、Pb、W、Nb、Ta等 14种非稀土杂质。研究了各稀土基体对被分析元素的基体效应 ,选择了相匹配的内标元素。比较了标准曲线法与标准加入法的测定结果。确定了用内标元素校正基体效应及仪器漂移 ,以标准曲线法直接测定。进行了加料回收和精密度实验 ,回收率在 94%～ 113%之间 ,RSD<10 %。被分析元素的检出限为 0 .0 1～ 0 .2 0 ng/ m L,测定下限为1～ 2 0 μg/ g。     

Increased-contrast, high-spatial-resolution, diffusion-weighted, spin-echo, echo-planar imaging

An insertable head gradient coil with a maximum gradient amplitude of 45 mT/m and a rise time of 150 musec along all three major axes was used to collect high-spatial-resolution, single-shot, spin-echo, echo-planar, diffusion-weighted magnetic resonance images with b values ranging from 0 to 2,200 sec/mm2. Improvements in spatial resolution allowed better visualization of large white matter tracts and their relation to adjacent anatomic structures. Excellent contrast and anatomic detail were revealed for most structures in the brain when a sufficient number of acquisitions were collected.     

原子荧光光谱法测定土壤中的铅、铬、镉、汞、砷、锌、铜、镍等元素研究

土壤无机污染物铅、铬、镉、汞、砷、锌、铜、镍这八大重金属,是一般土壤检测中的必检项目。金属元素在土壤中积累富集后,有可能通过雨水迁移,造成地下水,地表水污染,或者通过农作物进入食物链,进而影响食品安全和人体健康,因此,对这些元素的检测显得尤为重要。本文采用原子荧光光谱法对土壤中的金属元素进行测量,同时结合微波消解技术对样品进行处理,确保测量数据的准确性。     

Susceptibilities of non-Pseudomonas aeruginosa gram-negative nonfermentative rods to ciprofloxacin, ofloxacin, levofloxacin, D-ofloxacin, sparfloxacin, ceftazidime, piperacillin, piperacillin-tazobactam, trimethoprim-sulfamethoxazole, and imipenem

Agar dilution MICs of 10 agents against 410 non-Pseudomonas aeruginosa gram-negative nonfermentative rods were determined. MICs at which 50 and 90% of the isolates were inhibited, respectively, were as follows (in micrograms per milliliter): sparfloxacin, 0.5 and 8.0; levofloxacin, 1.0 and 8.0; ciprofloxacin, 2.0 and 32.0; ofloxacin, 2.0 and 32.0; D-ofloxacin, 32.0 and > 64.0; ceftazidime, 8.0 and 64.0; piperacillin with or without tazobactam, 16.0 and > 64.0; trimethoprim-sulfamethoxazole, 0.5 and > 64.0; imipenem, 2.0 and > 64.0. With the exception of those for Stenotrophomonas maltophilia, Burkholderia cepacia, and Alcaligenes faecalis-A. odorans, agar dilution MICs for all strains tested were within 1 dilution of inhibitory (bacteriostatic) levels as determined by time-kill methodology.