HFCVD法沉积金刚石薄膜中热丝优化方法

本文探讨了在HFCVD(hot filament chemical vapor deposition)沉积金刚石薄膜中热丝数量、位置等几何参数对温度场和辐射场的影响.利用系统热传递模型和计算机辅助的数值解方法得到了该方法沉积大面积金刚石薄膜中衬底表面温度分布和热辐射能量密度分布.发现金刚石薄膜的均匀性受热辐射能量密度分布影响较大.进一步给出了沉积面积为100mm×100mm的金刚石薄膜的最佳参数.     

Fe、Mn掺杂干凝胶的制备、表征及催化臭氧氧化邻二氯苯性能(英文)

采用溶胶-凝胶法制备Fe、Mn掺杂的干凝胶材料(XFe和XMn),并对其催化臭氧氧化去除邻二氯苯(o-DCB)的性能进行了研究.通过X射线光电子能谱(XPS)、X射线衍射(XRD)、透射电镜(TEM)、扫描电镜(SEM)、压汞仪和氮气吸附等技术对Fe、Mn掺杂的干凝胶材料进行表征.结果表明:XFe和XMn中存在三价金属氧化物等活性物种,金属相无明显的衍射峰且金属颗粒的尺寸较小,表明金属颗粒在干凝胶载体上获得较好的分散性;相比于单独臭氧氧化时44%的o-DCB去除率,XFe和XMn的添加使得o-DCB去除率分别达到58%和72%,XFe和XMn显示了较好的催化活性;XFe和XMn的金属溶出状况不同,在水溶液中浸泡5h后它们的金属溶出率分别为2%和8%左右.     

STRESS ANALYSIS IN CUBIC BORON NITRIDE FILMS BY X-RAY DIFFRACTION USING sin2 ψ METHOD

The boron nitride (BN) films containing cubic boron nitride (c-BN) and hexagonal boron nitride (h-BN) were prepared by radio frequency a ssisted thermal filament chemical vapor deposition. The stress and strain in BN films were investigated by X-ray diffraction analysis using the sin² ψ method. The results showed that both c-BN and h-BN in the same film have similar values of elastic strain, however, the compressive stress in c-BN is much greater than that in h-BN for the same film. Both stress and strain gradually decre ased with the increase of substrate temperature (T_s). The effective stress in the films calculated by the effective stress model increased with the increase of T_s. Furthermore, the dependence of effective stress in the films on T_s was also investigated.     

RP-HPLC法测定唐古特铁线莲中芦丁的含量

建立了唐古特铁线莲中芦丁含量测定的RP-HPLC方法.色谱条件:采用C18柱 (4.6 mm×250 mm,5 μm),流动相:V(甲醇)∶V(0.4% H3PO4)=55∶45,流速:1.0 mL/min,柱温:30 ℃,检测波长:360 nm,芦丁在0.24～1.2 μg范围内成良好的线性关系,r=0.9992,回收率RSD=1.0%,对青海省不同地区唐古特铁线莲中芦丁进行了定量分析,测定结果:不同产地该药材中芦丁的含量有较大差异,含量在0.119%～0.317%之间.     

Enhancement of light trapping in thin-film solar cells through Ag

Forward-scattering efficiency (FSE) is first proposed when an Ag nanoparticle serves as the light-trapping structure for thin-film (TF) solar cells because the Ag nanoparticle’s light-trapping efficiency lies on the light-scattering direction of metal nanoparticles.Based on FSE analysis of Ag nanoparticles with radii of 53 and 88 nm,the forward-scattering spectra and light-trapping efficiencies are calculated.The contributions of dipole and quadrupole modes to light-trapping effect are also analyzed quantitatively.When the surface coverage of Ag nanoparticles is 5%,light-trapping efficiencies are 15.5% and 32.3%,respectively,for 53and 88-nm Ag nanoparticles.Results indicate that the plasmon quadrupole mode resonance of Ag nanoparticles could further enhance the light-trapping effect for TF solar cells.     

STRESS ANALYSIS IN CUBIC BORON NITRIDE FILMS BY X-RAY DIFFRACTION USING sin2 ψ METHOD

The boron nitride (BN) films containing cubic boron nitride (c-BN) and hexagonal boron nitride (h-BN) were prepared by radio frequency a ssisted thermal filament chemical vapor deposition. The stress and strain in BN films were investigated by X-ray diffraction analysis using the sin² ψ method. The results showed that both c-BN and h-BN in the same film have similar values of elastic strain, however, the compressive stress in c-BN is much greater than that in h-BN for the same film. Both stress and strain gradually decre ased with the increase of substrate temperature (T_s). The effective stress in the films calculated by the effective stress model increased with the increase of T_s. Furthermore, the dependence of effective stress in the films on T_s was also investigated.     

CVD法沉积金刚石薄膜中成核与生长的势垒研究

探明成核与生长的机理对于沉积高质量金刚石薄膜是十分重要的.本文采用PM3方法,计算了化学汽相沉积金刚石薄膜成核与生长阶段反应势垒.研究了对于不同反应气体(甲烷和乙炔)脱氢和增加沉积基团势垒的差异.结果说明,无论是成核阶段,还是生长阶段,脱氢势垒都小于加生长基团的势垒.然而,增加乙炔基的势垒大于增加甲基的势垒,这可能是因为乙炔分子必须打开C≡C键才能沉积到衬底表面.