离子轰击引起的表面形貌对Ag的溅射产额的影响

用捕获膜技术和卢瑟福背散射(RBS)谱仪测定Ag靶在27keV Ar⁺离子轰击下的溅射原子角分布,从而确定不同剂量下Ag的溅射产额,并对其靶点表面形貌进行扫描电子显微镜(SEM)观察。结果发现,所有的角分布都呈over-cosine形状,但其溅射产额却随着表面形貌不同而不同。根据溅射产额Y与轰击离子入射角φ变化关系,讨论不同轰击剂量下溅射产额的差别,肯定了表面形貌是影响溅射产额的一个重要因素,并由此提出“表观产额”的新概念。 关键词：     

正偏离Bragg定律的二元化合物靶中离子射程参数研究

研究了正偏离Bragg定律,即计算S_e(E)值高于实测S_e(E)的二元系化合物靶的离子射程特性。文中应用“regular”观点引入了“双原子模型”,在二元化合物靶的射程计算中,不仅考虑相同“原子对”对离子的阻止本领S₁₁(E),S₂₂(E),而且考虑不同“原子对”对离子的阻止本领S₁₂(E),S₂₁(E)。文中还应用Berthelot关系,使S₁₂(E)=S₂₁(E)=(S₁₁(E)·S₂₂(E))^1/2,则二元系靶的阻止本领及总的射程为NS(E)=1/2[(N₁S₁₁(E))^1/2+(N₂S₂₂(E)^1/2)]², R=4/a[x-A₁(arctg(2x+f)/△^1/2-arctg(f/△^1/2))-B₁(ln(x+g)²/g²·e/(x²+fx+e)) -b/2 ln(x²+fx+e/e)。这里X=E^1/2,E为离子注入能量,所有其它常数是与离子和靶的质量、原子序数有关的常数。结合文献[1]提出的R与R_p,R_p与△R_p的关系式,可计算得正偏离系统的投影射程R_p及其偏差量△R_p。并对各关系式的物理意义作了阐明。 关键词：     

Al-50wt% Sn合金的离子溅射研究

用捕获膜技术和卢瑟福背散射(RBS)分析,测定Al-Sn多相合金在30keV Ar⁺离子轰击时Al和Sn的溅射原子角分布。溅射后的样品用扫描电子显微镜(SEM)进行观察,并用电子微探针分析仪(EPMA)对轰击样品(靶点)和未轰击样品作成分分析。结果表明,Al的溅射原子角分布近于cosine形状,而Sn却是over-cosine型角分布。本文给出一个按不同表面形貌特征划分的各元素富集区i进行叠加的产额表达式,Y(θ)=∑Y_i(θ),解释了实验结果。 关键词：     

一维复合势垒中的Larmor钟

利用Larmor钟方法计算了一维复合势垒系统中的隧穿时间．从计算结果，对由Larmor钟所定义的Larmor时间在复合势垒中的有效性、可加性，以及它们与透射时间τ_T、反射时间τ_R、逗留时间τ_D的关系作了讨论．6个Larmor时间中，τ_xT,τ_xR,τ_yT和τ_yR都不是有效的时间量，它们不能为隧穿时间提供有效的描述，只有τ_yT和τ_yR满足可加性和判据τ_D＝Tτ_yT+Rτ_yR，它们最有可能给出透射时间τ_T、反射时间τ_R．τ_yT,τ_yR与势垒的对称性有关，等式τ_yT＝τ_yR是否成立与势垒是否对称有关． 关键词：     

退火对Co35(SiO2)65颗粒膜巨磁电阻效应的影响

采用多靶离子束溅射镀膜机制备了一系列不同退火温度的Co₃₅(SiO₂)₆₅（体积百分数）颗粒膜样品,发现样品的巨磁电阻效应随着退火温度T_a的升高而单调下降.应用磁力显微镜对样品的磁结构进行了观测,发现随着退火温度的升高,近邻的Co颗粒的磁矩倾向于平行排列,形成磁畴结构,从而导致Co₃₅(SiO₂)₆₅颗粒膜巨磁电阻效应单调下降. 关键词：     

Ni原子倾斜轰击Pt(111)表面低能溅射现象的分子动力学模拟

采用嵌入原子方法的原子间相互作用势,通过分子动力学模拟详细研究了以不同角度入射的低能Ni原子与Pt (111)基体表面相互作用过程中的低能溅射行为.结果表明:随着入射角度从0°增加到80°,溅射产额Y_s和入射原子钉扎系数S的变化均可以根据入射角θ近似地分为以下三个区域:当θ ≤ 20°时,Y_s和S几乎保持不变,其值与垂直入射时接近,溅射原子的发射角分布和能量分布也与垂直入射时的情 关键词： 分子动力学模拟 入射角 低能溅射     

等离子体金属表面氮化中放电温度对氮原子态粒子的影响

采用快电子和重粒子(N₂⁺,N⁺,N_f)混合的Monte Carlo模型,研究了氮直流辉光放电等离子体金属表面氮化过程中.e-N_2s及N₂⁺-N_2s两种碰撞离解过程产生的原子态粒子(N⁺,N)的产生率和氮化粒子(N⁺,N_f)轰击靶表面的能量、粒子数密度及入射角分布随气体温度的变化规律.结果表明,使阴极靶处活性粒子(N⁺,N_f)的能量高且粒子数密度大,存在一个最佳放电温度;粒子(N⁺,N)的产生率及在靶表面的密度数都随着放电气体温度的升高而减少;有大量中性快原子N_f在工件表面小角入射,且粒子(N⁺,N_f)角分布受温度的影响很小.     

BaF2晶体的取向和入射束的剂量对溅射的影响

２７ｋｅＶ Ａｒ^＋离子束沿法向分别入射在ＢａＦ₂单晶（１１１），（１００）和（１１０）的晶面上，用捕获器方法和Ｒｕｔｈｅｒｆｏｒｄ背散射分析法测定了Ｂａ原子的溅射角分布和溅射产额。结果发现不同取向的晶体表面，它们的溅射产额有明显差异。当用剂量为５×１０¹⁷ｉｏｎ／ｃｍ²的Ａｒ^＋离子分别轰击这三种晶面时，其溅射产额的顺序Ｙ_１００＞ｙ_１１１＞ｙ_１１０．对已被上述剂量辐照过的晶面再作相同剂量轰击时，测得的溅射产额明显增大。这些结果被认为是由于在离子辐照过程中表面晶格受损逐步增大所致。 关键词：     

同位素择尤溅射角分布研究

本文从理论和实验两个方面探讨了同位素溅射角分布问题。从实验上得到的同位素溅射角分布曲线表明,在垂直靶面方向轻同位素择尤溅射,而在倾斜方向,则重同位素择尤溅射。在理论上考虑了原子级联碰撞过程中的能量和动量传输的不对称性,给出了一个与实验结果相符的同位素溅射角分布表达式。 关键词：     

GeC薄膜的射频磁控反应溅射制备及性质

用射频磁控反应溅射法在ZnS衬底上制备了GeC薄膜,研究了工艺参数对Ge靶溅射及GeC薄膜红外透射性能的影响.衬底温度较低时GeC薄膜中含有H,形成了CH₂,CH₃,Ge-CH₃等,使薄膜产生红外吸收;随衬底温度升高,薄膜红外吸收明显减小.靶基距、射频功率、Ar:CH₄气体流量比、总气压对靶面中毒及溅射影响较大,但对GeC薄膜红外吸收影响较小.靶面中毒严重时,所制备无氢GeC薄膜附着性能差,随靶中毒减弱薄膜附着性能变好.优化工艺后,在ZnS衬底上制备了附着性能良好的无氢GeC薄膜,其折射率约为1.78,薄膜中C的含量比Ge的大,二者主要形成了C—Ge键.所制备的GeC/GaP红外增透保护膜系对ZnS衬底有良好的增透效果. 关键词： GeC薄膜 红外透射光谱 射频磁控溅射 XPS     

低温高压下的Na5Eu(WO4)4的发光和晶体场参数

用低温金刚石对顶砧高压显微光谱系统在20—300K低温和0—10GPa高压范围内研究了白钨矿型化学计量的基质发光晶体四钨酸铕钠Na₅Eu(WO₄)₄中Eu³⁺的发光.确定了Eu³⁺荧光谱线和能级在低温下的压力移动率.它随温度变化,表明温度和压力对Eu³⁺谱线作用不是独立无关的.按晶体场理论简化方法推导了能级的晶体场参数表达式,并按实验数据拟合出在不同低温下晶体场参数随压力的移     

A study of the elastic scattering of polarized deuterons from 60Ni and 90Zr nuclei

Five quantities, σ₀, iT₁₁, T₂₀, T₂₁ and T₂₂, have been measured for the elastic ($\text{d}$, d) scattering from ⁶⁰Ni at 9 and 12 MeV and from ⁹⁰Zr at 10, 11 and 12 MeV over a wide angular range. Excitation functions for σ₀ and T₂₀ have been also measured at an angle of 175°(lab) in the approximate energy range of 6–13 MeV for both target isotopes. The experimental results, together with similar data published earlier for 15 MeV have now been analysed using the optical model with the complex central, spin-orbit and tensor T_R potentials. Excellent fits are obtained for the angular distributions for all five measured quantities. The main features of the excitation functions are also well reproduced. Five of the optical-model parameters can be fixed. Three other parameters can be constrained by simple mass dependence functions. Further evidence for the presence of an imaginary component of the spin-orbit potential is supplied by the analysis of the present data.     

无定形靶中离子注入的R,Rp,△Rp的理论计算

本文在Thomas-Fermi势能基础上,导出了全射程R的解析解:R=2/a[E^1/2-A₁(arctg(2E^1/2-f)/△^1/2+arctg f/△^1/2)+B₁ln((E^1/2-f)²)/(E-fE^1/2+d) ·d/f²],其中A₁,B₁,f,d和△均为与离子及靶的质量、原子序数有关的常数。结合导出的η=R/(R_p)(R_p指投影射程)比值的双曲线函数关系 η=F(μ)[A₂(μ)+(B₂(μ))/(ε^1/2+C)],和ω=R_p/△R_p(△R_p指投影射程的标准偏差)比值的线性关系ω=A₃(μ)ε^1/21/2+B₃(μ),可简便而又准确地计算R,△R_p,R_p.这里F(μ),A₂(μ),B₂(μ), B₃(μ)和A₃(μ)为μ的代数函数,μ为离子与靶的质量比,C是经验常数.并对η等关系式的物理意义作了讨论。上述公式的计算结果与Gibbons的数值解结果及有关实验结果作了比较,表明可用于元素半导体如Si、二元化合物如GaAs以及三元化合物如SiO₂等;既对较轻离子适用,也对重离子适用,具有一定的普适范围。     

Nonisothermal nucleation in the CuCl solid solution in glass: Formation of two distributions of nanoparticles of a new phase in the solid solution with a negative jump of the nucleation temperature

The processes of nonisothermal nucleation in the CuCl solid solution in glass with a negative jump of the nucleation temperature have been investigated using optical spectroscopy and exciton-thermal analysis. Two distributions of CuCl nanoparticles differing in the average radii R (2.3 and 14.0 nm) have been obtained for the temperature drop from T ₁ = 700°C to T ₂ = 500°C. The formation of two distributions of CuCl particles has been numerically simulated and the agreement between the experimental and calculated radius distributions of CuCl particles has been obtained.     

Formation of two distributions of nanoparticles of a new phase in a solid solution

Processes of the formation of the double distribution of CuCl nanoparticles in glass in two-stage annealing have been analyzed. The distribution of CuCl nanoparticles with the average radius R ₁ = 14 and 18 nm appears in 20 and 40 min at temperature T ₁ = 700°C in samples 1 and 2, respectively. By this time, the formation of new clusters ends, and only the growth of previously formed clusters occurs (the second stage of nucleation). Then, the formation of the CuCl phase continues at T ₂ = 500°C. A decrease in the temperature is accompanied by a decrease in the critical radius of particles of a new phase. For this reason, the formation and growth of new CuCl nuclei begin again and the second distribution with a mean radius of 1 nm or larger is formed. As a result, double distributions of CuCl nanoparticles with significantly different mean radii are formed in samples 1 and 2. The concentration and mean radius of CuCl particles in distributions have been determined from the optical absorption spectra of CuCl nanocrystals at 80 K in the wavelength range of 300–500 nm.     

Interference of fission amplitudes of neutron resonances and <Emphasis Type="Italic">T</Emphasis>-odd asymmetry for various prescission third particles in the ternary fission of nuclei

Differential cross sections for reactions of the true ternary fission of nuclei that was induced by cold polarized neutrons were constructed with allowance of the effect that Coriolis interaction and the interference between fission amplitudes of neutron resonances excited in fissile nuclei upon incidentneutron capture by target nuclei exerted on angular distributions of prescission third particles (alpha particles, neutrons, or photons). It is shown that T -odd TRI- and ROT-type asymmetries for prescission alpha particles are associated with, respectively, the odd and even components of the Coriolis interaction-perturbed amplitude of angular distributions of particles belonging to the types indicated above. These asymmetries have angular distributions differing from each other and stemming from a nontrivial dependence of these components on the neutron-resonance spins J _s and their projections K _s onto the symmetry axis of the nucleus involved. It is shown that angular distributions of prescission photons and neutrons from reactions of the ternary fission of nuclei that is induced by cold polarized neutrons are determined by the effect of Coriolis forces exclusively. Therefore, the emerging T-odd asymmetries have a character of a ROT-type asymmetry and are universal for all target nuclei.     

The permittivities of PVDF/PMMA blends at hydrostatic pressure

The complex permittivities of poly(vinylidene fluoride)/poly(methyl methacrylate) (PVDF/PMMA) blends have been measured under variation of temperature T(20°-60°C), frequency v(5 Hz-300 kHz), and hydrostatic pressure p (0-260 MPa). The values can be represented by a master curve with the shift factors △p/△ log (v/Hz) = ?140 MPa at room temperature and △ (1 /T) /△ log (v/Hz) = ?2. 10^?4 K^?1 at atmospheric pressure. The dependence of the activation energy △E _A on pressure p is then given by △E _A=(100 + 0.02 MPa^?1 p) kJ/mol. Furthermore, the results indicate that the β-relaxation of PVDF is due to motions in the crystal-amorphous interphase. The interactions between the two polymers, which are miscible at all compositions, disturb the correlations between the PVDF monomer units at that location as well as the mobility of the PMMA side group.     

由观测无胁强作用下的热膨胀和电阻研究金属玻璃(Fe0.85Ni0.15)84B16的结构弛豫

本文通过长度、电阻和热膨胀系数的测量研究了(Fe_0.85Ni_0.15)₈₄B₁₆金属玻璃结构弛豫和退火温度T_a的关系。基于上述物理量对结构弛豫的关系,对曲线作了分析和讨论。在退火温度为175℃至250℃之间结构弛豫随T_a的变化率最大。 关键词：     

Transverse momentum and angular distributions of hadrons in e+e− jets from QCD

Hadron jets in e⁺e^? annihilation will broaden at high energies due to gluon bremsstrahlung. With nonperturbative p_T effects dying out rapidly, the basic features of hadron jets can be calculated in perturbation theory. We examine the p_T distribution of secondarily produced hadrons. This is uniquely connected with the deviation from the 1 + cos²θ dependence of single particle inclusive distributions. We discuss what can be learned about the gluon fragmentation given the p_T and/or angular distributions. A sum rule is derived which establishes a relationship between the average p_T² and α_S.     

NiTi合金中应力诱导的I/C相变及其界面动力学的研究

在改装了的拉力试验机上,以不同的拉伸速率ε(0.79—18×10^-5s^-1)进行加、卸载试验,并用中间扭摆和四端电位法同时测量了Ni-49at％Ti合金丝在应力诱导I/C相变过程的内耗Q^-1、模量M/M₀、电阻率ρ/ρ₀和应力-应变曲线。研究了应力循环和应变速率的影响。在Q^-1-ε曲线上出现Q^-1峰,而在f²-ε曲线上出现与之相对应的模量极小。内耗峰的高度Q_p^-1和模量亏损值均随ε增大而增大。根据界面动力学模型和内耗的实验数据,计算得应力诱导I/C相变过程界面的动力学关系为V=V^*(△G—△G_R)^m,V^*和m为动力学参数,△G_R为相变过程中运动相界面所受的阻力,计算得△G_R≈1cal/mol。讨论了内耗和模量亏损、软模效应之间的关系。 关键词：