Quantum calculations in a unique rest frame

The distribution of astronomical redshifts and the cosmic background radiation define a unique inertial reference frame. This paper contains an investigation of questions concerning quantum theory which arise with the introduction of a unique rest frame into spacetime. The Mössbauer effect, photon pair production, and photoelectric effect are treated together with photon scattering by a moving reflector and the Compton effect. Dirac's 1928 quantum theory of electrons is shown to yield its well-known energy spectrum for the hydrogen atom independently of the velocity of the atom relative to the rest frame.1. Address for the academic year 1990–91: 415 Graduate Studies Research Center, University of Georgia, Athens, Georgia 30602, USA.     

Influence of pulse plating conditions on the structure and properties of pure and composite nickel nanocrystalline coatings

An additive-free Watts type bath containing micron- and nano-SiC particles (1 μm and 20 nm respectively), as well as ultrafine-WC particles (200 nm), was used for the production of pure Ni and nickel matrix composite electrocoatings under both direct and pulse current conditions. Moreover, nickel nanocrystalline deposits were obtained from a Watts type bath containing small amounts of 2-butyne-1,4-diol, in order to investigate the combined advantages of additives and pulse technique on the properties of the deposits. The influence of the variable electrolysis parameters, the particle size and the organic additive concentration on the surface morphology, the structure and properties of the deposits were discussed. It has been proved that the application of pulse electrodeposition affects drastically the structural characteristics and properties of the deposits and under well-defined conditions could lead to the preparation of nanostructured materials with improved mechanical properties. Published in Russian in Elektrokhimiya, 2008, Vol. 44, No. 6, pp. 802–811. The text was submitted by the authors in English.     

Guideline to Authors

正1.Aims and scope Chinese Physics C(CPC)covers the fields of Particle Physics,Nuclear Physics,Astrophysics and Cosmology related to particles and nuclei,Detectors,Related Electronics and Experimental Methods,Accelerator,Synchrotron Radiation and other related fields in the aspects of experiments,theories and their applications.     

高择优取向Mo薄膜的直流磁控溅射制备及其电学性能

使用直流磁控溅射法在玻璃基底上沉积Mo薄膜,采用X射线衍射仪、原子力显微镜和四探针测试系统研究了溅射工艺对Mo薄膜的结构、形貌和电学性能的影响.结果表明:当基片温度为150 ℃时,薄膜获得(211)晶面择优取向生长,而在低于250 ℃的其它温度条件下,样品则表现为(110)晶面择优取向生长.进一步的表面形貌分析显示:薄膜的粗糙度随基片温度变化不明显,其值大约为0.35 nm,随溅射功率密度的增大而变大|电学性能方面:随着溅射功率密度的升高,薄膜导电性能迅速增强,电阻率呈现近似指数函数衰减|随着基底温度的升高,薄膜的电阻率先减小后增大,当基底温度为150 ℃时,薄膜电阻率降低至最小值2.02×10-5 Ω·cm.     

Hydrogen bonding of modified bases involving Watson‐Crick sites: Crystal structure and conformation of Benzyl 6‐aminopurine‐7‐carboxylate

Crystals of benzyl 6‐aminopurine‐7‐carboxylate (C₁₃H₁₁N₅O₂) are monoclinic, space group C2/c, Z = 8, with a = 25.448 (9), b = 6.052 (1), c = 16.975 (6)Å, β = 112.05 (5)°, M = 269.27, D_m= 1.49, D_x= 1.48 g/cm³. The structure was determined from three‐dimensional diffractometric data by the multisolution technique and refined to a final reliability factor of 0.068. The molecule is planar with an intramolecular hydrogen bond from one of the amino hydrogens, H_a(N6) to the keto oxygen O(10) of the acyl group. The molecules are hydrogen bonded across the center of inversion by a pair of intermolecular hydrogen bonds using the Watson‐Crick sites. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

择优取向MgO在Si衬底上的直流溅射制备及其性能表征

采用直流磁控溅射并通过优化工艺参数,在（100）Si衬底上成功制备了高度（100）择优的MgO薄膜和MgO/TiN双层膜结构.对 （100）MgO择优取向温度影响机理做了详细讨论,并利用XRD,AFM,FESEM等手段研究了在（100）Si和（100）TiN/Si两种衬底上,不同工艺条件下MgO薄膜的表面和断面微观结构,表征了MgO薄膜的柱状生长结构和与TiN薄膜的良好外延关系.在对薄膜光学特性的研究中,利用Sellmeier模型获得了Si上MgO薄膜在可见光波段的折射率参数（550 nm处折射率为1.6 关键词： MgO薄膜 择优取向 直流溅射 折射率拟合     

电化学沉积Fe单晶纳米线生长中的取向控制

利用电化学沉积方法，发现了一种能够动态地控制铁纳米线生长方向的沉积方法，利用该方法沉积了包括［110］取向，［200］取向及非晶态三种结构和取向的一维Fe纳米线阵列.对于三种纳米线阵列，测量了它们的磁特性，分析发现具有[200]择优取向纳米线阵列的方形度，各向异性特性和矫顽力都比[110]取向阵列有很大的改善. 关键词： 磁性纳米线 电化学沉积 取向控制     

Arms races as iterated prisoner's dilemma games

Many important aspects of arms races are captured by the iterated prisoner's dilemma (IPD) game. In this analysis, strategies are developed and analyzed for IPD games which most resemble arms races; those which are finite, uncertain and time varying in length. It is shown that, under certain conditions, it can be rational to unilaterally cooperate following a series of mutual defection. A number of conclusions concerning arms race behavior are drawn.     

Solution structure of the palladium(II) complex of 1,4,7,10-tetrathiacyclododec-2-ene-2,3-dicarbonitrile

The solution structure of the Pd(II) complex of mn-12-S4 was studied in detail by NMR spectroscopy. The stoichiometry of the complex was determined by 1H NMR titration experiments. 3J(H,H) coupling constants were extracted from the 2D J-resolved NMR spectrum of the complex providing information concerning the S-C-C-S torsional angles. Further conclusions about the conformation of [Pd(mn-12-S4)](BF4)2 were drawn from experimental NOEs. The results of the NMR study were corroborated by molecular modelling.     

Processing of β-BaB2O4 Thin Films Through Metal Organics

β-BaB₂O₄ (β-BBO) thin films were successfully synthesized by the sol-gel method using metallo-organic compounds. A stable BBO precursor solution was prepared from barium metal and boron triethoxide or 2,4,6-triethoxycyclotriboroxane in a mixture solvent of ethanol and 2-ethoxyethanol. As-precipitated powder formed by hydrolysis of the precursor solutions crystallized to ψ phase, which was transformed to β phase at higher temperatures. The transformation temperatures of powders from ψ to β phase of the ethoxide system and the boroxane system were 600 and 680°C, respectively. The calcination of precursor films in a mixture gas of water and oxygen was found to decrease the crystallization temperature of β-BBO films on Pt sheet substrates. The precursor films prepared from the ethoxide system and the boroxane system crystallized to β-BBO on Pt (111)/glass substrates at 500 and 550°C, respectively. The BBO films on Pt(111)/glass substrates showed the strong (006) preferred orientation. The β-BBO films on Pt(111)/glass substrates showed the second harmonic generation (SHG) of the 532 nm light on irradiation with 1064 nm light. The SH power from the BBO films was correlated with the fundamental power through the square-law proportionality based on the theory. The SHG efficiency of the BBO films was dependent upon the film thickness.