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The formulation of the statistical mechanics of the - phase transition in hydrogenmetal-systems is extended in such a way as to include the elastic anisotropy of the host crystal. The corresponding reduction of symmetry leads to qualitative modifications of the results. Depending on hydrogen concentration and temperature, phases with homogeneous,C
3- andC
2-symmetric equilibrium hydrogen distributions are formed. The transitions between these phases are investigated, and the relation of their orders and the corresponding changes in symmetry is studied. Differences between isotropic and anisotropic systems are discussed. 相似文献
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Huili Wang Ailian Duan Jingwen Mao Baoguang Che Wenwei Wang Meiping Ma Xuedong Wang 《Journal of fluorescence》2013,23(1):103-113
Herein, we report the effects of six different room temperature ionic liquids (RTILs) on fluorescence spectra of 17α-estradiol (EE1) and 17β-estradiol (E2). The selected RTILs belonged to the compound classes of 1-alkyl-3-methylimidazolium tetrafluoroborate ([CnMIM]BF4) and 1-alkyl-3-methyl imidazolium hexafluorophosphate ([CnMIM]PF6). RTILs had a gradual quenching effect on fluorescence intensity (FI) of EE1 and E2, and the quenching process followed the well-known Stern-Volmer theory. The quenching mechanism of EE1 and E2 by RTILs was demonstrated to be dynamic quenching. Additionally, the overall quenching efficiency by [CnMIM]BF4 was higher than [CnMIM]PF6. The increased carbon chain length of RTILs did not lead to obvious differences in FI for EE1 and E2. The quenching efficiency showed irregular trend at three different temperatures (25, 35 and 45 °C). RTILs such as [C4MIM]PF6 had the different fluorescent effects on organic chemicals with different fluorophores. The enhancing effects of [C4MIM]PF6 were observed on strong fluorescence chemicals (dansyl chloride, rhrodamine B, 1,10-phenanthroline, norfloxacin), while quenching effect on weak fluorescence chemicals (EE1 and E2). In theory, these results provide a theoretical foundation for deep insight into their interaction mechanism between RTILs and estradiol. 相似文献
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研究了α 苯丙酮酸 (PPA)和 β 苄基 α 苯丙酮酸 (BPPA)的UV ,IR ,MS和1 HNMR等光谱学性质。UV光谱中 ,PPA在 2 4 0和 365nm处出现吸收峰 ,BPPA只在 2 1 0nm处有吸收 ,这证明PPA存在烯醇式结构而BPPA则没有。IR光谱中 ,PPA由于采取烯醇式二聚体结构 ,在 1 62 4 38和 1 697 2 5cm- 1 处分别出现两个羧基CO峰 ,BPPA则在 1 70 6 6cm- 1 和 1 72 8 6cm- 1 处分别出现酮基CO和羧基CO吸收峰。同时还对MS及1 HNMR图谱进行了详尽的解析 ,并就两者化学结构上的差异进行了比较说明。 相似文献
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The hypernucleus Be is investigated in an α-α-Λ three-body model using the Faddeev formalism. We use an α-α interaction in which the Pauli-forbidden
states are correctly taken into account and we employ some phenomenological potentials between the α and Λ particles. We obtained
two bound states for and , and three resonance states of . We studied the properties of these states by calculating the components and the expectation values of the potential for
each partial wave. It is found that a few channels dominate in the α (α, Λ) and states, so that the alpha-clusters or the 8Be core are still alive in the nucleus. In a case where the two alpha particles are fixed on an axis the contour plots of
the distribution of the Λ particle are shown. With the assistance of these plots one can visually understand that some of
them are shell-model-like states while others are well developed cluster-model-like states. For the structure of Be, it is concluded that the Λ particle is loosely coupled in S- and P-wave orbits about the 8Be(0+) and 8Be(2+) core states. Finally, we discuss a redundant state in the Faddeev amplitude which could arise from the treatment of symmetrization.
Received June 25, 1998; revised April 13, 1999; accepted for publication December 29, 1999 相似文献
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We update our Standard Model predictions for g-2 of the muon and for the hadronic contributions to the running of the QED coupling,αh(5a)d(MZ2).Particular emphasis is put on recent changes in the hadronic contributions from new data in the 2π channel and from the energy region just below 2 GeV. 相似文献
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Akio Suzuki 《高压研究》2017,37(2):193-199
ABSTRACTThe pressure–volume–temperature (P–V–T) equation of state (EoS) of natural goethite (α-FeOOH) has been determined by an X-ray diffraction study using synchrotron radiation. Fitting the volume data to the third-order Birch–Murnaghan EoS yielded an isothermal bulk modulus, B0 of 85.9(15)?GPa, and a pressure derivative of the bulk modulus, B′, of 12.6(8). The temperature derivative of the bulk modulus, (?B/?T)P, was –0.022(9)?GPa?K?1. The thermal expansion coefficient α0 was determined to be 4.0(5)?×?10?5?K?1. 相似文献
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利用热分析技术(TG/DTG)对聚--甲基苯乙烯(PAMS)在氮气气氛下以不同升温速率为条件进行热降解动力学研究。研究结果表明:PAMS的热降解步骤为一步反应,在升温速率为10 ℃/min时,主要失重温度区间为302~343 ℃,热失重速率最大时温度为325 ℃。在同一温度下,随着升温速率的不断提高,主要降解温度向高温区移动。采用了Kissinger,Flynn-Wall-Ozawa及Coats-Redfern方法研究其动力学参数,确定了PAMS的降解活化能在160~220 kJ/mol之间、反应级数为一级。 相似文献
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我们在多次碰撞模型的框架下,分析了在核子-核子质子系中总能为SNN=31.2GeV的α-α碰撞中产生的带负电荷的粒子的多重数分布,投射核子在通过靶核时损失能量,损失的能量用于产生粒子的概念在计算中明确考虑.理论结果能较好符合实验. 相似文献
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C. A. Daniels S. H. Maron P. J. Livesey 《Journal of Macromolecular Science: Physics》2013,52(1):47-60
The Maron theory of polymer solutions was used to examine the 30°C vapor pressure data of Tait and Livesey on solutions of polyheptene-1, polydecene-1, polydodecene-1, and polyoctadecene-1 in toluene. For polyheptene-1 and polydecene-1, excellent agreement was obtained between theory and experiment over the entire concentration range studied. However, for the other two polymers, deviations were observed between the calculated and observed vapor pressures at higher solution concentrations. These deviations were used to show the presence of crystallinity in these and to ascertain the amounts. Further, it was shown that only one crystalline form of the polymer was present in the polydodecene-1, whereas in the polyoctadecene-1 two crystalline forms were detected. These observations, confirmed by measurements with a differential thermal analyzer (DTA), indicate that for polydodecene-1 and one of the crystalline forms in polyoctadecene-1 the crystallization involves alignment of both backbone and side chains; however, the lower melting form in polyoctadecene-1 appears to have only the side chains aligned in the crystal lattice. 相似文献
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The fluorescent probe 1,6-diphenyl-1,3,5-hexatriene (DPH) and DPH derivatives have been used to characterize structural and physicochemical properties of specific membrane domains. Steady-state and fluorescence decay measurements of three probes, DPH (1,6-diphenyl-1,3,5-hexatriene), TMA-DPH [1-(4-trimethyl-ammonium-phenyl)-6-phenyl-1,3,5-hexatriene], and a phosphatidylcholine derivative of DPH, DPH-pPC [2-(3-(diphenylhexatriene)propanoyl)-3-pamitoyl-L--phosphatidyl choline], have been performed in erythrocyte membranes and in lymphocyte plasma membranes. The steady-state fluorescence polarization of the three probes showed a similar trend in both membranes. In fact either in erythrocyte or in lymphocyte plasma membranes the fluorescence polarization values of DPH-pPC and TMA-DPH were similar, but significantly higher with respect to DPH. A better characterization of erythrocyte and lymphocyte plasma membranes was possible by using fluorescence decay measurements. The data suggest the possible use of different DPH derivatives to characterize specific domains in biological membranes. 相似文献
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M. V. Korolevich S. G. Kirillova V. N. Piottukh-Peletsky V. M. Andrianov 《Journal of Applied Spectroscopy》2008,75(5):613-620
A detailed interpretation of the IR spectrum of methyl-3,4-anhydro-α-D-talohexopyranoside that is based on complete calculation
of normal vibration frequencies and absolute IR absorption band intensities of the molecule and a comparison of the results
obtained with the corresponding experimental data is given for the first time. The influence of the epoxy group on the absorption
bands characteristic of the pyranose ring has been analyzed.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 5, pp. 597–605, September–October, 2008. 相似文献
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用α-结团模型计算新合成超重元素的半衰期,与已知的实验数据进行对比分析,发现理论和实验数据能够很好地符合,验证了α-结团模型对超重核研究的有效性.同时结合标准的形变Hartree-Fock模型核质量表给出半衰期理论计算结果,可供以后在理论或实验上研究超重核参考,在此基础上进一步分析超重核区域的α衰变能、双中子分离能和双质子分离能,并讨论Z=114和N=184处是否存在壳效应. 相似文献