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511.
Makrofol polycarbonate plastic track detectors have been exposed to
54
132
Xe -ions of energy 1.1 MeV/N from the cyclotron beam. The bulk etch rate and track etch rate are measured for different temperatures
and the activation energies are calculated. The maximum etched track length is compared with the theoretically computed range.
The critical energy loss is (dE/dx)
c
=5 MeV cm2 mg−1 for this detector material. 相似文献
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Using the newly introduced general ordering theorem by Shhandeh and Bazrafkan,we derive and generalize some quantum optical identities and give their applications. 相似文献
516.
Short-range order in the Ni -Ta system is studied both experimentally (by diffuse scattering of x rays) and theoretically (by the pseudopotential method). The existence of local order is found in the alloy Ni-7 at. % Ta. The short-range order parameter calculated by the pseudopotential method, using Animalu form factors, coincided in sign with that observed experimentally.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 21–25, December, 1976.In conclusion the authors thank Prof. A. A. Katsnel'son for valuable advice and discussions of the results. 相似文献
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Lead is quantitatively adsorbed as the lead N-methylethylxanthocarbamate (MEXC)-benzyldimethyltetradecylammonium (BDTA) ion pair complex on microcrystalline naphthalene in the pH range 4.0-11.0. The metal is desorbed with HCI and determined by differential pulse polarography. Alternatively lead can be quantitatively adsorbed on the adsorbent (MEXC-BDTA-naphthalene) packed in a column at a flow rate of 1-2 mL/min and determined similarly. Dissolved oxygen is removed by adding a few milliliters of 4% NaBH4 solution. The detection limit is 0.12 microg/mL at the minimum instrumental settings (signal-to-noise ratio, 2). Linearity was obtained over the concentration range 0.3-20.0 microg/mL with a correlation factor of 0.9998 and a relative standard deviation of +/- 0.98%. Various parameters, such as the effect of pH, volume of aqueous phase, flow rate, and the interference of a large number of metal ions and anions, were studied in detail to optimize the conditions for the trace determination of lead in various standard alloys, standard biological materials, and environmental samples. 相似文献
520.
Xi Z Hwang GS Goldberg IH Harris JL Pennington WT Fouad FS Qabaja G Wright JM Jones GB 《Chemistry & biology》2002,9(8):925-931
Bulged regions of nucleic acids are important structural motifs whose function has been linked to a number of key nuclear processes. Additionally, bulged intermediates have been implicated in the etiology of several genetic diseases and as targets for viral regulation. Despite these obvious ramifications, few molecules are capable of selective binding to bulged sequences. Prompted by the remarkable affinity of a natural product metabolite, we have designed and prepared a series of readily accessible synthetic agents with selective bulge binding activity. Furthermore, by screening a library of bulge-containing oligodeoxynucelotides, correlations between structure and affinity of the agents can be drawn. In addition to potential applications in molecular biology, the availability of these spirocyclic agents now opens the door for rational drug design. 相似文献