氟化类金刚石薄膜的拉曼和红外光谱结构研究

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Deposition of Diamond-Like carbon Films by High-Intensity Pulsed Ion Beam Ablation at Various Substrate Temperatures

Diamond-like carbon (DLC) films have been deposited on to Si substrates at substrate temperatures from 255℃ to 400O℃ by a high-intensity pulsed-ion-beam (HIPIB) ablation deposition technique. The formation of DLC is confirmed by Raman spectroscopy. According to an x-ray photoelectron spectroscopy analysis, the concentration of sp^3 carbon in the films is about 40% when the substrate temperature is below 300℃ C. With increasing substratetemperature from 25℃ to 400℃, the concentration of sp^3 carbon decreases from 43% to 8%. In other words,sp3 carbon is graphitized into sp^2 carbon when the substrate temperature is above 300℃. The results of xray diffraction and atomic force microscopy show that, with increasing the substrate temperature, the surface roughness and the friction coefficient increase, and the microhardness and the residual stress of the films decrease.     

Optical Properties of ZnFe2O4—SiO2 Granular Films Prepared by Radio—Frequency Magnetron Sputtering

We report on the optical properties of ZnFe2O4-SiO2 granular films prepared on quartz substrates by the radio-frequency magnetron sputtering method.Post-annealing was performed at different temperatures under flow oxygen atmosphere.The morphology and Structures of ZnFe2O4 nanoparticles were characterized by x-ray different line types in the optical absorption curves of ZnFe2O4-SiO2 granular films.The critical transition of line types occurs when ZnFe2O4 changes from amorphous to crystalline,and the transition temperature increases with the increasing content of ZnFe2O4.There is an obvious blueshift of the optical absorption edge of the granular films with the decreasing annealing temperature.     

Fluorescence Microscopy of Nanoscale Silver Oxide Thin Films

The experimental conditions for photoactivated intermittent fluorescence from nanoscale silver oxide were studied with fluorescence microscopy.Strong fluorescence was observed from the Ag2O particles with size of 10-20nm excited with both blue and green light .We observed the saturation of Photoexcitation with blue light and explained the experimental results using the model of agglomeration of silver atoms to form small clusters and the fluorescence of Ag2 and Ag3 clusters.     

粒子鉴别中dE/dx和TOF的权重

在北京谱仪数据分析中,粒子鉴别使用了dE/dx和TOF的信息.在利用dE/dx和TOF联合鉴别粒子时,通常的做法是把两者的χ²值等权重相加(χ²方法).在不同的动量区间,dE/dx和TOF对粒子的鉴别能力不同.本文给出两者联合鉴别时不同动量区间的权重,并构造一个新的线性变量来进行粒子鉴别     

基片温度对坡莫合金薄膜结构和磁电阻的影响

用磁控溅射方法制备了系列坡莫合金Ni80Fe20薄膜。利用X射线衍射、扫描电子显微镜和原子力显徽镜分析了薄膜的结构、晶粒取向、薄膜厚度、截面结构和表面形态。用4点探测技术测量了薄膜的电阻和磁电阻。结果表明：随衬底温度的升高，晶粒明显长大。膜内的缺陷和应力显著减小，而且增强了薄膜晶粒的[111]择优取向。结果表明，薄膜电阻率显著减小，而磁电阻显著增大。     

粒子分辨CCT方法中的δ电子效应

提出了切伦科夫相关时间测量(CCT)中初始粒子在辐射体里产生的δ电子的干扰问题,以及降低干扰的方法. 通过模拟计算给出了北京τ-C工厂探测器初步设计中CCT的π/K分辨本领.     

离子注入合成β-FeSi2薄膜的显微结构

采用MEVVA源(Metal Vapor Vacuum Arc Ion Source)离子注入合成β-FeSi2薄膜,用常规透射电镜和高分辨电镜研究了不同制备参数下β-FeSi2薄膜的显微结构变化. 研究结果表明:调整注入能量和剂量,可以得到厚度不同的β-FeSi2表面层和埋入层. 制备过程中生成的α,β,γ和CsCl型FeSi2相的相变顺序为γ-FeSi2→β-FeSi2→α-FeSi2,CsCl-FeSi2→β-FeSi2→α-FeSi2或β-FeSi2→α-FeSi2. 当注入参数增加到60kV,4×1017ions/cm2,就会导致非晶的形成,非晶在退火后会晶化为β-FeSi2相,相变顺序就变为非晶→β-FeSi2→α-FeSi2. 随退火温度逐渐升高硅化物颗粒逐渐长大,并向基体内部生长,在一定的退火温度下硅化物层会收缩断裂为一个个小岛状,使得硅化物/硅界面平整度下降. 另外,对于β-FeSi2/Si界面取向关系的研究表明,在Si基体上难以形成高质量β-FeSi2薄膜的原因在于多种非共格取向关系的并存、孪晶的形成以及由此导致的界面缺陷的形成.     

首次测定短寿命缺中子同位素153Er和157Yb的EC/β+衰变纲图

利用¹⁶O重离子束轰击¹⁴²Nd和¹⁴⁷Sm同位素靶分别生成¹⁵³Er和¹⁵⁷Yb.借助氦喷嘴带传输系统和X-γ、γ-γ符合测量方法分离鉴别核素并测量其衰变性质.首次建立了¹⁵³Er和¹⁵⁷Yb的EC/β⁺衰变纲图.从中指认出¹⁵³Ho的一个新三(准)粒子态和两个新单粒子态,指认出¹⁵⁷Tm的一个新的同质异能态和一条新转动带.低位能级系统分析表明:在Ho和Tm这两条奇A核的同位素链中基态形状的转变区都在中子数86和88之间.     

同步辐射光电子能谱表征MgO在GaAs（100）上淀积过程中的氧物种

用同步辐射光电子能谱表征了不同氧分压下通过热蒸发镁在ＧａＡｓ（１００）面制备氧经物超薄膜过程中的氧物种，结果表明表面氧物种的形式与镁氧配比有关，较高的氧分压下于形成活泼的分子离子等氧中间体，因此通过控制镁氧比可以制备高效的薄膜模型催化剂或适合于功能材料集成的规则氧化物过渡层，氧物种的形式可以通过能谱中不同的原子或分子轨道电子跃迁来有效地区分。