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We study the behaviour of atoms in a field with both static magnetic field and radio frequency (rf) magnetic field. We calculate the adiabatic potential of atoms numerically beyond the usually rotating wave approximation, and it is pointed that there is a great difference between using these two methods. We find the preconditions when RWA is valid. In the extreme of static field almost parallel to rf field, we reach an analytic formula. Finally, we apply this method to 87 Rb and propose a guide based on an rf field on atom chip. 相似文献
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Poly(A)~+ RNA was isolated from 9 specimens of human primary hepatic carcinoma, 1 non-tumorous liver tissue adjacent to cancer and 1 normal liver tissue samples. The Oligo-dT cellulose-purified poly(A)~+ RNAs were subjected to formaldehyde agarose gel electrophoresis, Northern transfer and hybridization with various ancogene probes. Two RNA species, 5.6 kb and 2.2 kb wore identified by N-ras gone hybridization in 6 out of 9 mRNA samples from primary hepatic carcinoma specimen. N-ras specific mRNA was not detectable in mRNA samples from normal human liver and tumor surrounding cirrhotic tissue. No detectable hybridization of mRNA from hepatoma and normal liver with Ki-ras or Ha-ras was observed.As human N-ras gene has been identified in DNA of mouse transfeetants transformed with PHC DNA, it strongly suggests that N-ras gene might be responsible for the transforming activity of part of cases of human liver cancer. 相似文献
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微波消解电感耦合等离子体质谱法测定大气气溶胶中的铂元素 总被引:2,自引:0,他引:2
采用高压密闭微波消解系统消解样品,结合电感耦合等离子体质谱(ICP-MS)法,测定了上海市区大气气溶胶样品中Pt元素的含量。实验采用数学校正方法扣除HfO复合离子对Pt元素测定的干扰,用标准溶液模拟样和铂族元素标准物质检验方法的可靠性,其测定值与标准值相吻合。Pt、Hf的检出限分别为0.3 ng/L、3.0 ng/L;Pt和Hf的空白值分别为1.0±0.1 ng/L和29.0±1.0 ng/L。对采集的3个气溶胶样品的测定结果表明:上海市区大气气溶胶中Pt的平均含量为1.5±1.0 pg/m3,低于世界其他城市。 相似文献
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This paper reports an experiment of creating Bose-Einstein
condensate (BEC) on an atom chip. The chip-based Z-wire current with
a homogeneous bias magnetic field creates a tight magnetic trap,
which allows for a fast production of BEC. After a 4.17-s forced
radio frequency evaporative cooling, a condensate with about 3000
atoms appears. The transition temperature is about 300~nK. This
compact system is quite robust, allowing for versatile extensions
and further studying of BEC. 相似文献
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We propose a surface planar ion chip which forms a linear radio frequency Paul ion trap. The electrodes reside in the two planes of a chip, and the trap axis is located above the chip surface. Its electric field and potential distribution are similar to the standard linear radio frequency Paul ion trap. This ion trap geometry may be greatly meaningful for quantum information processing. 相似文献
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