放射性同位素

Ca is widely abundant in nature and its rodioisotope 41 Ca is a cosmogenic nuclide with a half\|life of 10 5 years. However, the 41 Ca/ 40 Ca ratio in natural samples is very low and can only be measure d by accelerator mass spectrometry. The application of 41 Ca is ve ry i mportant not only in the life science but also in geological dating, global envi ronment change studies and astrophysics.

1 引言Ca在自然界中广泛存在，它不仅是人体中含量最丰富的元素之一[1] ，也是众多其他物质的组成部分。41Ca(半衰期为 1.0 3× 10 5a)属于Ca的放射性同位素中的一种，其衰变方式为轨道电子俘获，只发射3.3keV的X射线，天然样品中41Ca 40 Ca的值很小。

For cooperation to the utilization of heterosis and the selection of "three lines" in crops by the people, we have studied the metabolic condition of "three lines" in Sorghum and rice with irradiant isotops.

配合群众性杂种优势利用及&三系&选育科学实验，应用放射性同位素对高梁及水稻&三系&植株的代谢情况进行了研究。

For cooperation to the utilization of heterosis and the selection of"three lines"in crops by the people,we have studied tbe metabolic condition of"three lines"inSorghum and rice with irradiant isotops.

配合群众性杂种优势利用及&三系&选育科学实验，应用放射性同位素对高粱及水稻&三系&植株的代谢情况进行了研究。

The extraction distribution ratios have been measured as a function of shaking time, counter anion, pH value, picric acid concentration, extractant concentration, diluent and temperature.

利用放射性同位素示踪技术，系统研究了32种开链大环化合物对Am／Eu及Cs／Na的萃取分离行为。

The suitable concentration of free Ca〓 and the suitable pH for the activity of the tonoplast-bound CDPK was 10μmol/L and 6. 5, respectively. Its active site was provably oriented toward the cytoplasm.

用我们建立的非放射性同位素测定方法和免疫印迹鉴定了液泡膜上存在一种具有钙依赖蛋白激酶活性的膜固有蛋白。

Because of the special design of SPET/CT, it may cause motion artifacts, alignment mismatch, patient collision, and wires knotting of other machine.

SPET/CT提供各种核医检查不同的放射性同位素於身体中吸收部位的准确解剖定位。

The primary difference is that in RIA systems the competitive antibody is labeled with a radioisotope and in FIA the antigen is labeled with a compound that fluoresces under the appropriate light rays.

主要不同的是在放射免疫测试法中，竞争性抗体是用放射性同位素标记；在免疫荧光测试法中，用一种在适当光波长下能发出荧光的物质。

Short-lived radionuclides and long-lived isotope systems are normally used to date chondrites; the former systems can provide only relative ages while the later can provide absolute formation ages of chondrules, in contrast.

陨石年代学研究中常用定年工具包括短半衰期和长半衰期放射性同位素体系，其中前者可以给出陨石形成的相对年龄，而后者则可以给出绝对形成年龄。

There are two main types of uses of radioactive isotopes in biochemistry.

在生物化学中，放射性同位素主要有两方面的应用。

The reactor is only one of four in the world that produce medical radioactive isotopes.

该反应堆是世界上仅有的四个生产医用放射性同位素的反应堆之一。

Neither the killing of Mr Zarqawi nor any breakthrough on the political front will stop the insurgency and the fratricidal murders in their tracks.

在对危险的南部地区访问时，他斥责什叶派民兵领导人对中央集权的挑衅行为。

In fact,I've got him on the satellite mobile right now.

实际上 我们已接通卫星可视电话了