搜索结果: 136-150 共查到“知识库 无机化学”相关记录1634条 . 查询时间(3.134 秒)
Determination of Arsenic in Water by Potentially Portable Methodology
Arsenic Field Analysis Portable Instrument Water
2014/11/20
Arsenic contamination in groundwater is a worldwide problem. The existing portable field test kits can not provide accurate results when the arsenic concentration is around 10 μg L-1 or lower. This re...
Reactive Heterocycles for Examining Polyketide Biosynthesis
beta-lactam fluorescent polyketide site-specific labeling
2014/11/20
Polyketides are a class of natural products that exhibit remarkable structural and functionally diversity and are highly sought after due to their medicinally important activities. For many decades no...
Development of Mass Spectrometry-Based Methods for Quantitation and Characterization of Protein Drugs: Transferrin as a Model Drug Delivery Vehicle
Mass Spectrometry O18 labeling Protein quantitation Transferrin
2014/11/20
In the last two decades, protein drugs have enjoyed a rapid growth and achieved a tremendous success in treating human diseases. However, the presence of physiological barriers greatly impedes the eff...
Sources and fate of nitrate in a groundwater-fed estuary elucidated using stable isotope ratios of nitrogen and oxygen
nitrate oxygen isotope
2014/10/16
We used d15N-nitrate (NO{
3 ) and d18O-NO{
3 to unravel the provenance and fate of NO{
3 in a groundwater-fed
estuary. A total of 13 monthly and two time series surveys were undertaken in the Werr...
阿尔金环形山花岗片麻岩同位素年龄及成因研究
地球化学 二长花岗片麻岩 阿尔金
2015/3/4
阿尔金中段环形山二长花岗片麻岩LA-ICP-MS锆石U-Pb年龄为928±9Ma。岩石SiO2含量为72.26%~74.34%,全碱(Na2O＋K2O)为7.22%~8.32%,Al2O3含量为12.40%~13.51%,含量较高;MgO为0.43%~1.07%,FeOT为2.09%~2.43%,CaO为1.02%~2.03%,TiO2为0.19%~0.32%,含量较低。岩石FeOT/MgO比值为...
玄武岩分相Sm-Nd内部等时线定年方法流程
Sm-Nd同位素 年代学 矿物内部等时线
2014/10/11
长期以来，对玄武岩精确测年一直是困扰地质学家的重大科学问题。玄武岩结构和组成特殊，岩石中矿物组成单一、锆石十分稀少，颗粒很细，采用物理方法挑选单矿物和锆石十分困难，很难应用内部等时线法和锆石U-Pb法研究其成岩时代。而全岩样品间因岩浆分异产生的147Sm/144Nd比值差别很小，等时线年龄相对误差较大；Rb含量很低，Rb/Sr比值很小，全岩Sm-Nd法、Rb-Sr法常常不能给出正确可信的年龄。根据...
A pathway to diphosphorus from the dissociation of photoexcited tetraphosphorus
pathway diphosphorus from the dissociation photoexcited tetraphosphorus
2014/8/21
We report a computational study of an energetically favorable pathway for the excited-state dissociation of a tetrahedral P4 molecule into two P2 molecules via the simultaneous breaking of four chemic...
用一定浓度的醋酸钙和氢氧化钠溶液与酸洗脱灰处理后的低阶烟煤在煮沸的条件下分别进行离子交换，测
定羧基的滴定终点由空白试验的pH值确定，而总酸性基的滴定终点由酚酞指示剂确定；筛选了不同浓度和
煮沸时间对测定结果的影响.结果表明：醋酸钙溶液在0.15mol/L、煮沸2h，氢氧化钠溶液在0.25mol/L、煮沸
1h分别可得到较准确的羧基和总酸性基含量.3种低阶烟煤中羧基含量均在0.2mmol/g...
滇西保山地块晚白垩世-古近纪岩浆活动代表了新特提斯演化阶段的一次重要岩浆事件，其岩浆岩成因、源区属性及地球动力学背景尚不明确。本文对出露于保山地块北部漕涧地区的花岗岩类进行了全岩地球化学、锆石U-Pb年代学和Hf同位素组成研究。2件样品锆石U-Pb年龄结果分别为73.32±0.19Ma（MSWD=0.68）和73.44±0.20Ma（MSWD=1.3）。岩体具有高硅（SiO2=73.76%~74....
Groundwater-derived dissolved inorganic and organic carbon exports from a mangrove tidal creek: The missing mangrove carbon sink?
Groundwater-derived dissolved inorganic organic carbon exports mangrove tidal creek
2014/4/2
A majority of the global net primary production of mangroves is unaccounted for by current carbon budgets. It has been hypothesized that this “missing carbon” is exported as dissolved inorganic carbon...
胶西北高Ba-Sr郭家岭型花岗岩岩浆混合成因：岩石地球化学与Sr-Nd同位素约束
岩浆混合 Sr-Nd同位素 胶西北
2014/10/14
胶东是我国最重要的金矿集区，拥有全国近四分之一的金资源储量，其95%以上赋存在玲珑型和郭家岭型花岗质岩体内。然而，关于花岗岩类的成因，尤其是早白垩世郭家岭型花岗质岩石成因仍存有争议。郭家岭型花岗岩质岩体自西向东包括三山岛岩体、新城岩体、上庄岩体、北截岩体、丛家岩体和郭家岭岩体等。其中，新城岩体是迄今为止在胶东矿集区内发现的唯一赋存超大型金矿床的郭家岭型花岗质岩体，呈北东向岩株状侵入到玲珑型花岗岩体...
胶北地体地壳演化：玲珑黑云母花岗岩继承锆石U-Pb年龄、微量元素和Hf同位素证据
U-Pb年龄 Hf同位素 岩石再循环 胶北地体
2014/10/14
胶北地体晚侏罗世下地壳重熔的玲珑黑云母花岗岩大面积出露，其中残留有大量继承锆石，记录了多期热事件，为复杂的地壳演化过程提供了重要线索。论文通过分析玲珑黑云母花岗岩中继承锆石的U-Pb年龄、微量元素和Hf同位素组成，探讨了胶北地体的地壳演化历史。结果显示胶北地体前寒武纪经历了~2.9Ga和~2.7Ga两期主要的地壳生长事件，~2.5Ga和2.2~1.8Ga两期地壳重熔改造事件，~2.5Ga和1.95...
锂同位素研究是非传统稳定同位素地球化学研究的前沿,已广泛应用于从地表到地幔的岩石圈及流体等固体地球科学的研究领域.准确测定锂同位素比值是应用该同位素体系的前提.本文报道了国际上7种常用地质标准物质(BHVO-2、JB-2、BCR-2、AGV-2、NKT-1、L-SVEC、IRMM-016)的锂同位素组成数据.分析中采用硝酸-氢氟酸混合酸消解岩石标准样品,通过3根阳离子交换树脂(AG50W-X8,2...
球形ADN的吸湿机理
动态吸湿性分析法 吸湿机理 吸湿性能
2014/12/3
用动态吸湿性分析法和扫描电镜研究了球形二硝酰胺铵（ADN）的吸湿过程和吸湿过程中ADN形貌的变化，探讨了ADN的吸湿机理。结果表明，ADN吸湿过程可分为平缓吸湿(Ⅰ),急剧增强吸湿(Ⅱ)和潮解(Ⅲ)三个阶段，Ⅰ、Ⅱ阶段是水蒸汽与ADN固体表面的作用，Ⅲ阶段是水蒸汽与ADN液化膜表面的作用。Ⅰ阶段吸湿过程为多分子层吸附，符合BET理论模型；该阶段水与ADN之间的作用力对ADN吸湿性能起主导作用；Ⅱ阶...