查询词典 isotope

The most common isotope of oxygen, for example, has an atomic weight of 16, but there are also rarer isotopes with weights of 17 and 18, caused by additional neutrons in their nuclei.

例如很常见的同位素氧，原子重量是16，但是还有更为稀少的重量为17和18的同位素，这是因为它们的原子核中有额外的中子。

In determination of atomic weight and isotope certified reference materials preparation, isotopic abundance almost is determined by this method.

在原子量的精确测量和同位素标准物质的研制工作中，一般采用此方法对元素同位素丰度进行定值，测量仪器多采用表面热电离质谱计。

YANG Kui ,ZHOU Ling,WANG Yan-zhenThe Nationbal Center for Isotope of Engineering and Technology,ChinaInstitude of Atonic Energy,Bei-jing 102413,China

单位：中国原子能院国家同位素工程技术研究中心，北京 102413关键词：双抗夹心；免疫PCR；人促甲状腺激素TSH

In order to find the difference of the isotopic composition of different organic compounds before and after complexation, the autogamy standard sample is performed by molecular sieve adsorption to study the variation of the isotope compositions of n-alkanes, isoalkanes and cyclanes.

通过对自配标准样品进行S分子筛吸附试验，测定了用5分子筛吸附法分离前后正构烷烃、异构烷烃和环烷烃碳同位素值，探讨试验前后碳同位素值的变化。

Analysis shows that the effects of the laser spontaneous axial magnetic field and the laser spontaneous transverse magnetic field are opposite, and there is competition between them in the process of isotope separation.

分析认为，激光等离子体中的自生轴向磁场和环形磁场在同位素的分离过程中可能起着相反的作用，二者相互竞争。

All the volcanic rocks present younger K-Ar age (less than 5Ma), which can be termed as Cenozoic rocks. In general speaking, volcansim can be dividied into two eruptive stages. In the first stage, volcanic rocks for Pliocene epoch (4. 4-5Ma) consist of basanite and tephrite, which distributed on Mt. Crater, Cape Bird, and southern bank of Bonney Lake; In the second stage, volcanic rocks for Quaternary (less than 1 Ma) are mainly composed of latite, which are distributed on Cape Rodeys and Cape Evens.On the basis of geochemical data such as major elements, trace elements , rare earth elements, isotope, microprobe analysis, combined with main achievement taken by previous researcher in this area, conclusions are drawn basically as follows

所喷发的火山岩K-Ar年龄值均小于5Ma，为新生代火山岩，大体上可以分为两个喷发阶段，第一个阶段为上新世火山岩(年龄值为4.4-5.0Ma)，主要由碧玄岩和碱玄岩组成，分布于罗斯岛上的克雷克特山、鸟角和泰勒谷的博尼湖南岸；第二阶段为第四纪火山岩(年龄值均小于1Ma)，主要由安粗岩组成，分布于罗斯岛上的罗德角和伊万思角，通过主要元素、微量元素、同位素结合电子探针以及前人的研究成果，我们大体上可以得出如下认识

Armed with this information and further analyses, Rumble, lead author Bekker, and colleagues propose the following scenario today in Science . Early in Earth's history, volcanic eruptions spewed massive amounts of sulfur dioxide into the atmosphere, where UV sunlight broke down the gas and created the odd sulfur isotope ratios. The sulfur descended with the rain and accumulated into sedimentary beds on the sea floor. Once there, superheated water from geothermal vents at various locations on the sea floor cooked the sulfur into sulfide. Finally, nickel-bearing magma welled up from Earth's mantle, combining with the sulfide to form nickel sulfide and encasing the compound inside volcanic rock called komatiite.

凭借这份资料和进一步的分析，朗布尔、研究论文的第一作者贝克及同事们今天在《科学》杂志上提出了如下的推测：在地球早期的历史上，火山爆发将大量的二氧化硫气体喷射到空中，太阳的紫外线将其分解，产生了奇特的硫同位素比值，这种硫随雨降下，积存于海底沉积层中；一旦到达海底，海底各处的地热出口所产生的温度过高的水把硫加热成硫化物；最终含有镍的岩浆从地幔中涌出，跟硫化物结合形成硫化镍，并将硫化镍包裹在一种叫做"科马提岩"的火山岩中。

The understanding of biogeochemical cycle of hydrogen, oxygen, carbon, nitrogen, and sulfur elements in nature ecosystem have increased substantially in the past two decades owing to the improvement of gas isotope ratio mass spectrometer and the wide application of isotopic studies with these elements.

近20年由於「气相同位素比值质谱仪」的改良和氢、氧、碳、氮和硫等稳定同位素的广泛研究，稳定同位素的研究技术已实质增加我们对於这些元素在自然生態系中生地化循环的瞭解。

Systematical variations of silica contents and silicon isotope compo- sitions are observed from their roots to stem to leaves, which provide us reliable evidences for studying the mechanisms of adsorption, transpor- tation and precipitation of silicon in plants, as well as the role of plants in silicon biogeochemical cycle.

由根往茎叶，硅的含量与同位素组成呈规律性变化。为研究植物中硅的吸收、搬运与沉淀机制，探讨植物在硅的生物地球化学循环中的作用提供依据。

In addition, carbon and nitrogen isotope and its ratio was important indicator in the riverine biogeochemistry study.

另外碳氮同位素及其比值在当前的河流有机质生物地球化学研究中仍起着非常重要的示踪作用。

Objective To investigate the effects of interleukin-1 β converting enzyme gene on the biologic characteristics of ovarian cancer cells.

目的 探讨白细胞介素-1 β转换酶的表达，对卵巢癌细胞生物学特性的影响。

Campylobacter: This illness is the most commonly identified cause of diarrheal illness in the world.

弯曲：这种病是最常见的原因查明腹泻病，在世界上。