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991.
选择5~6岁儿童64名,随机分为两组,分别服用太阳神奶(A组)和一般乳酸奶(B组),每天服用100mL。连服9周,检测全血中微量元素锌、铁、铜、钙、锰的变化。经检测,服用太阳神奶A组经统计学分析,微量元素锌、铁、锰呈显著或非常显著变化。  相似文献   
992.
We analyze approximate approaches to the modeling of the thermomechanical behavior of physically nonlinear materials under harmonic loading. The approaches are based on various harmonic-linearization schemes and the concept of complex moduli. Mechanical and mathematical features of various schemes are considered. Some modifications of the model are proposed to account for various aspects of material behavior under harmonic loading. The problems of vibration and dissipative heating of physically nonlinear bodies are formulated. The main thermomechanical characteristics are analyzed for some classes of problems.The study was partially sponsored by the State Fund for Basic Research of the Ministry of Education and Science of Ukraine (Grant No. 01.07/00050).Translated from Prikladnaya Mekhanika, Vol. 40, No. 10, pp. 3–34, September 2004.  相似文献   
993.
本文通过分子动力学模拟研究了纳米铜团簇的自扩散性质,结果表明Nc8949铜团簇自扩散系数随温度的升高而增大,在温度为1000 K时纳米铜团簇的扩散系数随团簇半径的倒数基本呈线性增加.同时指出在常温下团簇几乎无扩散行为,而某些文献中关于常温下晶粒扩散分子动力学模拟结果是模拟体系宏观转动造成的虚假现象.?  相似文献   
994.
Colin J.R. Sheppard  Kieran G. Larkin   《Optik》2003,113(12):548-550
In this paper we report experimental studies of nonvolatilephotorefractive holographic recording in doping In(3mol%), which exceed the so-called threshold, in Ce:Cu:LiNbO3 crystals. The In:Ce:Cu:LiNbO3 crystal was grown by the Czochralski method and oxidized. The OH absorption band of In:Ce:Cu:LiNbO3 crystal is 3507cm−1. The nonvolatile holographic recording in In:Ce:Cu:LiNbO3crystal is realized by two-photon fixed method. From the experiment, we found that the recording time of In:Ce:Cu:LiNbO3 crystal is lower than that of Ce:Cu:LiNbO3 crystal and there are a little lose of nonvolatile diffraction efficiencies between In:Ce:Cu:LiNbO3 and Ce:Cu:LiNbO3 crystals. In this paper, the mechanism of OH absorption band shifting and two-photon fixed was discussed, too.  相似文献   
995.
在强流电子储存环调试运行时,克服束流负载效应是十分重要的问题.本文应用电流源等效电路方法,推导了克服束流负载的理论,并在此基础上计算得出合肥800MeV 电子储存环束流改变时为保持高频腔系统匹配所要求的腔频失谐量的调整规律。  相似文献   
996.
Essentially single-phase Cu(Ba0.67Eu0.33)2(Ce0.33Eu0.67)2Cu2Oδ samples of the Cu-1222 phase with a fluorite-structured (Ce,Eu)-O2-(Ce,Eu) block between the superconductive CuO2 planes were synthesized in O2 atmosphere to exhibit superconductivity with Tc around 25 K. Wide-range tuning of oxygen content and thereby the overall hole-doping level of the phase was found possible through (i) temperature-controlled oxygen-depletion (TCOD) annealing carried out in a thermobalance in N2 at various temperatures (for reduction), and (ii) high-pressure oxygenation (HPO) treatments carried out in a cubic-anvil-type high-pressure apparatus in the presence of various amounts of Ag2O2 as an excess oxygen source (for oxidation). For the HPO samples a record-high Tc value of 62 K was achieved. On the other hand, deoxygenation to the oxygen content less than 9±δ≈8.9 was found to kill superconductivity. The degree of hole doping (both in overall and for the CuO2 plane and CuOδ charge reservoir separately) in the samples is discussed on the bases of Cu L-edge and O K-edge XANES data.  相似文献   
997.
In this work, the first three members (s=1, 2, 3) of the Co-12s2 homologous series of multi-layered copper oxides are gradually doped with holes through high-pressure oxygenation (HPO). The phases differ from each other only by thickness of the fluorite-structured layer block, (Ce,Y,Ca)-[O2-(Ce,Y)]s−1, between two identical CuO2 planes. High-resolution transmission-electron microscopy (HRTEM) and electron diffraction (ED) analyses together with both synchrotron X-ray and neutron powder diffraction data, reveal that as a consequence of HPO the charge-reservoir CoO4-tetrahedra chains get broken and the lattice symmetry of the Co-12s2 phases changes from orthorhombic to tetragonal. Oxygen contents are analyzed for the samples with wet-chemical and thermogravimetric techniques. The valence state of copper in the CuO2 plane is determined from Cu L-edge X-ray absorption near-edge structure (XANES) spectra to be compared with the values estimated through bond-valence-sum (BVS) calculations from the crystal structure data. The positive charge induced by oxygen loading (or aliovalent CaII-for-YIII substitution in CoSr2YCu2O7+δ) is found not to be completely accommodated in the CuO2 planes but be rather effectively trapped at the charge-reservoir Co atoms. Superconductivity appears in the Co-1212 (CoSr2YCu2O7+δ) samples with the copper valence of 2.13 or higher, whereas in the Co-1222 (CoSr2(Ce0.25Y0.75)2Cu2O9+δ) and Co-1232 (CoSr2(Ce0.67Y0.33)3Cu2O11+δ) samples Cu valence does not increase high enough to induce superconductivity.  相似文献   
998.
IntroductionDimericcopper(II)carboxylatescontainingavarietyofoxygenandnitrogen donorligandshavebeenextensivelyinvestigatedandtheirpreparations ,magneticandspectralpropertieshavebeenreviewed .1 5Differentkindsofcopper(II)carboxylateadductshavebeensynthesizedandalsodinuclearcopper(II)complexeshavebeenearlystud iedasusefulmodelstoestablishmagneto structuralcorre lationsforspinexchangebetweenmetalions .Inparticu lar,theoccurrenceofdicopperionsattheactivesiteofthevariousformsoftheoxygencarrierpro…  相似文献   
999.
By analysing the instability process of various nonlinear systems, we conclude that their instability precursors are the continual heightening of the response rate or response ratio.Applying this theory to earthquake prediction, we adopt the periodical change of the stress in crust caused by the tide-generating force as the loading and unloading. If we can measure the ratio of the response (such as crust deformation, gravity and seismicity) during the loading period to that during the unloading period, this parameter must contain some characteristic information about the seismogenic process.With nine earthquakes (M≥7) data that occurred in Chinese mainland during 1970-1988, we take the sum of square root o?energy of small earthquakes, which is called the released strain by Benioff, as the response to the tidal loading and unloading. We find that the response ratios of seven earthquakes increase obviously before the main earthquakes.  相似文献   
1000.
Nano-Copper and Cu/UDD (ultradispersed diamond) nanocomposites were separately prepared by reduction of CuCl2 aqueous solution and that doped with 0.7%(weight percent) of ultra-dispersed diamond. The as prepared nano-crystals were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR) and electron paramagnetic resonance techniques (EPR). It was found that homogeneous nucleation dominated the aqueous reduction reaction at high concentration and the diameter of nano-copper decreased as the reaction time shortened, yet at lower concentration heterogeneous nucleation predominated and the doped UDD functioned as heterogeneous nucleation. Otherwise large number of free-radicals existed in the nano-composites. Both of nano-copper and Cu/UDD nanocomposites were strong catalysts for AP decomposition, with Cu/UDD being a more effective one. The higher decomposition temperature for AP was 119 ℃ lower than that without catalyst. And the exothermic quantity of decomposition was from 590 J·g-1 to 1 400 J·g-1 by mix 2% of the Cu/UDD nanocomposites.  相似文献   
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