共查询到20条相似文献,搜索用时 180 毫秒
1.
考虑非对称势和阻尼下。研究庞小峰教授提出的氢键系统质子传递理论模型。其模型存在扭结孤子激发,给出孤子传递的精确解及质子传递的速度. 相似文献
2.
考虑非对称势和阻尼下,研究庞小峰教授提出的氢键系统质子传递理论模型,其模型存在扭结孤子激发,给出孤子传递的精确解及质子传递的速度. 相似文献
3.
简述了一个模拟质子、α粒子的蒙特卡罗径迹结构模型,考虑了质子、α粒子在水中输运时的电离、激发等非弹性散射机制,模拟计算了质子、α粒子在水蒸气(密度为1g/cm^3)中的径迹,质子、α粒子的能量范围为0.3—5MeV/u.考虑了产生的大量低能电子(能量下限为1eV)在水介质中的输运.计算得到的射程、径向剂量等参数,与实验数据符合得较好. 相似文献
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本文介绍并发展了一种从实验结合能及激发能提取质子-中子互作用能δVpn的方法,据此对N≥40全部偶偶核的基态及部分核的高自旋态的质子-中子互作用作了讨论.同时,还讨论了一些奇A核中特定组态的高自旋态的质子-中子互作用.结果表明,这类实验δVpn值包含着p-n互作用的各种多极项,主要是单极和四极项,而且灵敏地依赖于核的形变,组态与转动频率. 相似文献
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激光在次稠密等离子中传输, 由于频率下移而被俘获, 从而产生电磁孤立子. 根据先前理论及PIC 模拟给出的孤立子的演化过程, 对不同阶段孤立子的电磁场分布进行了建模. 使用Geant4蒙特卡罗程序, 模拟研究了激光加速产生的能量为几个MeV的质子束对后孤立子的照相. 分析了质子能量, 质子源尺寸等因素对照相结果的影响, 并利用了TNSA加速产生质子束的分幅特性, 开展了时间分辨的孤立子照相模拟研究. 模拟给出的质子照相结果验证了文献中给出的孤立子静电场模型, 为以后在实验上探测孤立子提供了理论依据.
关键词:
超短激光
质子照相
孤立子
蒙特卡罗方法 相似文献
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绿荧光蛋白的双光子激发的荧光特性研究 总被引:1,自引:0,他引:1
利用双光子激发方式研究了重组绿荧光蛋白(recombinant green fluorescent protein,简称rGFP)的光转换特性,研究结果表明rGFP具有较强的双光子激发荧光,双光子激发的荧光偏振光谱表明rGFP在辐照前质子态和去质态之间存在着有效的能量转移过程,rGFP辐照后导致生色团构象的变化,部分阻断了rGFP内源的氨基酸与生色团之间的能量转移过程,导致rGFP的双光子激发的荧光强度下降,观察到rGFP的三光子激发的荧光特性,这种三光子激发的荧光主要来源于rGFP内源的氨基酸(色氨酸,酪氨酸等)的吸收。研究结果对在实际使用定量的光显微镜时具有一定的指导意义。 相似文献
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采用Serebryany的复空间中的复坐标法,讨论了轴对称非均匀弹性介质中引力波对声子的作用效应,并给出了由引力波产生的激发力的表达式和相应的声子解。解的形式表明,平行于对称轴方向传播的引力波只对声子场的径向分量、切向分量产生扰动,垂直于对称轴方向传播的引力波则对声子场的径向分量、切向分量和轴向分量均产生扰动,扰动强度取决于切变模量径向分布函数的具体形式和引力波的振幅。此外,本文还将所得结果与含有螺旋位错的拓扑声子空间中引力波的扰动效应作了比较。
关键词: 相似文献
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QUANTUM-MECHANICAL PROPERTIES OF PROTON TRANSPORT IN THE HYDROGEN-BONDED MOLECULAR SYSTEMS 下载免费PDF全文
The dynamic equations of the proton transport along the hydrogen bonded molecular systems have been obtained by using completely quantum-mechanical method to be based on new Hamiltonian and model we proposed. Some quantum-mechanical features of the proton-solitons have also been given in such a case. The alternate motion of two defects resulting from proton transfer occurred in the systems can be explained by the results. The results obtained show that the proton-soliton has corpuscle feature and obey classical equations of motion, while the free soliton moves in uniform velocity along the hydrogen bonded chains. 相似文献
12.
PANG Xiao-Feng 《理论物理通讯》2002,38(4):407-414
The properties of proton transfer along hydrogen-bonded molecular systems are studied at finite temperature. The dynamic equations of the proton transport along the systems are obtained
by using a completely quantum mechanics method. From the dynamic equations and its soliton solutions we find out specific heat arising from the motion of solitons in the systems with finite
temperature and the critical temperature of the soliton in the protein molecules, which is about 318 K. This shows that we can continuously
study some biological phenomena in the living systems by this model. 相似文献
13.
We here study the influences of the temperature and
solvent ions in solution
on the states and properties of DNA by a new dynamical model. This model
admits three degrees of freedom per base-pair: two displacement variables
related to the vibrations of the hydrogen atom in the hydrogen bonds and
base (nucleotide), respectively, and an angular variable related to the
rotation of each base, which delineate different forms of motion of the
hydrogen atom and bases and the relations among them. In this model we
stress specially the important role of the hydrogen atom in the hydrogen
bonds of the bases in the dynamics of DNA. According to their properties of
motion we give the Hamiltonian of the system and the corresponding equations of
motion, and find out their soliton solutions. The solitons formed by the
displacements of the hydrogen atoms and bases and their rotations are the
excitation states arising from the energy absorbed by the DNA working at the
biological temperature. We give further the free energy of the thermal
excitation state in DNA system by transfer integral way and find out
the corresponding specific heat. The specific heat increases with the
increasing of the temperature and concentration of the solvent ions in the solution,
but is not linear changes in the region of high temperature. If compared with
experimental data, they are approximately consistent. Meanwhile we find that
the solvent ion concentration influences seriously on the stability, states,
and configurations of DNA. 相似文献
14.
Stimulated diffusion of protons in oxides such as ABO3 crystals and rutile TiO2 is discussed in the context of quantum Brownian motion. A self-consistent lattice-assisted proton hopping (LAPH) model is developed by going from white noise (characteristic of the standard stochastic theory of superionic conduction) to colored noise in the Markovian limit. This model differs from the commonly used ion jump models in that the hydrogen diffusion rate prefactor is identified as a quantity proportional to the frequency of phonon assistance. Application of the quantum fluctuation–dissipation theorem suggests that the dynamic activation energy for diffusion is a function of a bath-mode frequency. The LAPH model can predict enhanced rates of barrier jumping at room temperature compared to thermally activated proton diffusion. This indicates that low-temperature solid oxide devices are potential candidates for use in hydrogen energy research. The LAPH model offers a valid explanation for the mechanism of high protonic mobility recently observed for TiO2 in a picosecond transient pump-probe experiment. This unexpected dominant lattice relaxation channel must be considered as a new classical-like (but low-temperature) proton transfer mechanism. For vibration-assisted protonic jumps to occur at low temperature, the phonon assistance must be classified as a low-frequency vibration specific to each lattice. 相似文献
15.
Moustafa M. Habeeb 《应用光谱学评论》2013,48(1-2):103-140
Abstract Recent studies on proton transfer equilibria for many hydrogen bonded complexes are discussed. These studies employ various spectroscopic techniques as infrared, ultraviolet, 1H NMR, 13C NMR, 15N NMR and nuclear quadrupole resonance (NQR) spectroscopy. Special attention has been paid to Fourier transform infrared (FTIR), and it forms the main focus of this review, in particular for the study of proton transfer equilibria in proton sponges hydrogen bonded complexes. The influence of proton transfer equilibria on the physical, chemical and biological properties of hydrogen bonded complexes is shown. Some applications of proton transfer equilibria are also discussed. 相似文献
16.
Proton conductivity phenomena in 10% Y-doped barium and strontium cerate are investigated experimentally and by quantum molecular dynamics simulations. In particular the impact of deviations from the cubic perovskite structure on the formation and mobility of protonic charge carriers is investigated. For Y: SrCeO3, which shows a larger deviation from the ideal cubic perovskite structure, the concentration and mobility of protonic defects is significantly lower than for Y: BaCeO3. The first is due to the decay of the oxygen position into two sites, only one of which is involved in the formation of protonic defects. The symmetry reduction also leads to the formation of different one-dimensional proton diffusion paths, and unfavourable jumps between such paths are supposed to control the macroscopic proton diffusion coefficient in Y: SrCeO3. The analysis suggests the formation of strong but transient hydrogen bonds and inter-octa-hedra proton transfer between vertices for SrCeO3 in contrast to just intra-octahedra proton transfer for BaCeO3. Whereas for BaCeO3 the proton transfer step is identified to be rate-limiting at T= 1000 K, for SrCeO3 both proton transfer and reorientation are found to be of similar magnitude. 相似文献
17.
PANG Xiao-feng YU Jia-feng 《原子与分子物理学报》2004,21(Z1):317-318
We study and calculate the mobility and conductivity of proton transfer and influence of temperature on it by pang's dynamic model in hydrogen bonded systems, which coincide with experiments. We further study the mechanism of magnetization of ciguid water in the basis of this model. 相似文献
18.
The conductivity properties of protons in ice and
mechanism of magnetization of liquid water 总被引:7,自引:0,他引:7
From a study of electrical conductivity of protons in the hydrogen-bonded
chains in ice we confirm that the magnetization of liquid water is caused by
proton transfer in closed hydrogen-bonded chains occurring as a first order
phase transition, through which the ice becomes liquid water. We first study
the conductive properties of proton transfer along molecular chains in ice
crystals in our model. Ice is a typical hydrogen-bonded molecular system, in
which the interaction of localized fluctuation of hydrogen ions (H+)
with deformation of a structure of hydroxyl group (OH) results in soliton
motion of the protons along the molecular chains via ionic and bonded
defects. We explain further the quantum conductive properties of proton
transfer and determine its mobility and conductivity under constant
electric-field using a new theory of proton transfer, which agree with
experimental values. From features of first order phase-transition for
ice, and some experimental data of pure and magnetized water we confirm
further that there are not only free water molecules, but also many linear
and closed hydrogen-bonded chains consisting of many polarized
water-molecules in the liquid water. Thus a ring proton-current, which
resembles to a “molecular current” or a “small magnet” in solids, can
occur in the closed hydrogen-bond chains under action of an externally
applied magnetic field. Then the water molecules in the closed chains can be
orderly arrayed due to the magnetic interaction among these ring
proton currents and the externally applied magnetic field. This is just the
magnetized effect of the water. In such a case the optical and electronic
properties of the water, including the dielectric constant,
magnetoconductivity, refraction index, Raman and Infrared absorption
spectra, are changed. We determine experimentally the properties of the
magnetized water which agree with the theoretical results of our model.
However, the magnetized effect of water is, in general, very small, and
vanishes at temperatures above 100 ○C. 相似文献
19.
我们首先介绍了氢键系统的特性和质子在此系统中的运动特点及国际上对此问题研究的进展和存在的问题。接着较全面地描述我们提出的新理论的物理学基础、模型的特征和所形成的两类缺陷和质子孤子的特性。这个模型的最大特点是存在两类不同性质的非线性相互作用 ,它们之间的竞争和平衡导致了两类不同的缺陷和相应孤子的出现 ,这两类缺陷的协同和交替运动使质子在氢键系统中从一处传递到另一处。因此 ,此模型能完整地解释质子在氢键系统中的传递 ,在此基础上我们研究了重离子作非简谐振动和系统中存在的杂质及氢离子的迁移所产生的偶极矩等效应对质子孤子的影响以及在外场存在时 ,质子运动的特点 ,求出了质子在电场作用下的迁移率和传导率、大约分别为 (6 5 - 6 .9)× 1 0 - 6(m2 /v .s)和(7.6 - 8.1 )× 1 0 - 3/(Ωm) ,它刚好处在半导体范围内 ,与实验结果基本吻合。并且我们研究了质子传递的量子力学特性和质子孤子存在的临界温度 相似文献
20.
PANG Xiao-Feng 《理论物理通讯》2002,38(10)
The properties of proton transfer along hydrogen-bonded molecular systems are studied at finite temperature. The dynamic equations of the proton transport along the systems are obtained by using a completely quantummechanics method. From the dynamic equations and its soliton solutions we find out specific heat arising from the motionof solitons in the systems with finite temperature and the critical temperature of the soliton in the protein molecules,which is about 318 K. This shows that we can continuously study some biological phenomena in the living systems bythis model. 相似文献