圆偏振飞秒激光脉冲与低压氙气体靶相互作用软X射线辐射实验研究

利用平场光栅谱仪,分别在2和3 kPa的低气压下,测量了脉宽35 fs的圆偏振超强超短激光脉冲与5 mm长氙气体靶相互作用产生的波长在5～60 nm范围内的离子谱线。2 kPa时最强的跃迁为XeⅧ：4d105s(2S_1/2)—4d95s5p(2P_3/2)的17.085 6 nm线,3 kPa时最强的跃迁为11.343 nm的XeⅦ 4d105s2(1S0)—4d95s25f(3P₁)跃迁。两种气压下,Xe均被电离到XeⅦ,XeⅧ,XeⅨ态。     

26 ℃和常压至1.5 GPa压力下2-甲基戊烷拉曼光谱研究

利用碳化硅压腔在常压至1.5 GPa和26 ℃条件下对液态2-甲基戊烷进行了拉曼光谱测量,讨论了C—H拉曼峰频率、强度、面积、以及谱峰宽度随压力升高的变化规律。实验结果表明,2-甲基戊烷的拉曼位移在2 800～30 00 cm-1范围内的CH₃和CH₂的伸缩振动谱峰随着压力的增大均连续向高波数位移,其拉曼位移与压力的关系可以表示为ν_as(CH₃)=0.013 1p+2 960.1,ν_s(CH₃)=0.008 8p+2 871.0,ν_as(CH₂)=0.008 9p+2 930.2,ν_as(CH₂)’=0.007 0p+2 903.1和ν_s(CH₂)=0.007 9p+2 844.7。另外处理实验结果时发现,在0～1.5 GPa条件下,2-甲基戊烷的ν_as(CH₃)拉曼位移可以进行压力标定,其方程为：P(MPa)=76.2(Δν_p)_{2 960}+21.65(r2=0.995 8)。该压力体标定剂,适合于不希望有Si和Al等元素出现的体系。     

TRPO萃淋树脂从碱性氰化液中固相萃取Au(Ⅰ)机理研究

研究了TRPO-D3520萃淋树脂从碱性氰化液中固相萃取Au(CN)-₂的性能,并借助傅里叶变换红外光谱(FTIR)、X射线光电子能谱(XPS)和扫描电镜(SEM)等方法对固相萃取Au(Ⅰ)的机理进行了讨论。结果表明：阳离子表面活性剂CTMAB在固相萃取中起到了关键的作用,当待萃水相中加入的CTMAB与Au(CN)-₂的摩尔比达到1∶1时,TRPO-D3520萃淋树脂即对金具有良好的萃取性能;萃淋树脂负载金后,FTIR分析表明Au(CN)-₂中的C≡N伸缩振动吸收峰位于2 144 cm-1,TRPO中的PO伸缩振动峰由1 153 cm-1向低频移至1 150 cm-1;N(1s),Au(4f_7/2)和Au(4f_5/2)XPS谱揭示了树脂中金的价态和配位环境未发生变化,仍以Au(CN)-₂形态存在于萃淋树脂中;O(1s) XPS谱图表明,经固相萃取后,树脂中化学结合水的含量明显增加,化学结合水的峰面积由30.74%增加至42.34%;固相萃取后,P(2p)XPS谱图峰位由132.15 eV增加至132.45 eV,说明PO基团与水分子存在一定的氢键作用,生成P=O…H—O—H。综上可推测,TRPO-D3520树脂固相萃取Au(CN)-₂的过程为：离子对扩散至树脂孔内,被孔内的TRPO借助水分子为桥的氢键作用溶剂化而固相萃取。     

电子助进化学气相沉积金刚石中发射光谱的空间分布

采用蒙特卡罗方法,对以CH₄/H₂为源料气体的电子助进化学气相沉积(EACVD)金刚石中的氢原子(H_α,H_β,H_γ)、碳原子C(2p3s→2p2：λ=165.7 nm)以及CH(A2Δ→X2Π：λ＝420～440 nm)的发射过程进行了模拟,研究了不同CH₄浓度下各发射谱线的空间分布。结果表明,不同CH₄浓度下各发射谱线在反应空间的大部分区域内均随距灯丝距离的增大而增大,而当到达基片表面附近时有所减弱。随着CH₄浓度的增加,H谱线强度减弱,CH与C谱线强度增强。     

碳纤维在电化学处理中的拉曼光谱研究

采用激光拉曼光谱研究了电化学改性处理过程中聚丙烯腈基碳纤维的表面微结构变化,分析了不同处理时间下碳纤维的一级拉曼光谱特性。结果表明： 碳纤维的一级拉曼光谱可以拟合为4个峰,即D(D₁),G,D₂和D₃,表征碳纤维表面微结构变化的拉曼参数主要有D线和G线的积分面积比R(I_D/I_G),D₂线与G线的积分面积比I_D3/I_G,D₃线与G线比I_D3/I_G以及所有无序结构积分面积总和与G线积分面积的比值I_DS/I_G。电化学处理后,碳纤维表面无序度增大,D线和G线交叠度减小,R增大,I_D3/I_G增大,I_D2/I_G减小。随着处理时间的增加,I_DS/I_G不断增大,它与R值的变化趋势基本一致,并且可以更全面表征碳纤维表面结构有序性的变化。因此,利用激光拉曼光谱可以研究电化学改性处理过程中碳纤维表面的微结构变化规律。     

电子助进化学气相沉积金刚石中的光发射谱特性

采用蒙特卡罗方法,对以CH₄/H₂为源料气体的电子助进化学气相沉积(EACVD)金刚石中的氢原子(H_α, H_β, H_γ)、碳原子C(2p3s2p2∶λ=165.7 nm)以及CH(A2Δ→X2Π∶λ=420～440 nm)的光发射过程进行了模拟,气体温度随空间的变化采用温度梯度变化,研究了不同反应室气压及衬底温度下的光发射谱特性。结果表明,不同衬底温度下各谱线强度均随气压的增大先增大后减小; 当气压较低时,谱线强度随衬底温度的增大而减少,而气压较高时,谱线强度随衬底温度的增大而增大。     

X射线光电子能谱在炼油催化剂中的应用

X射线光电子能谱(XPS)能给出固体材料表面元素的定性、定量和化学态信息,是炼油催化剂最重要的表征手段之一。对XPS在加氢催化剂、超深度脱硫吸附剂、稀土改性Y型分子筛等典型炼油催化剂研究中的应用作了阐述和举例说明。对Mo(W)-Co(Ni)/Al₂O₃(SiO₂)型硫化态加氢剂,阐述了其无水无氧转移方法;总结了S(2p),Mo(3d),W(4f),Co(2p)和Ni(2p) XPS谱的识别、分峰拟合方法及各元素的典型化学态,从而获得活性金属的硫化度及催化剂硫化不完全原因。对S Zorb超深度脱硫吸附剂,介绍了利用XPS激发的ZnLMM俄歇峰获得Zn存在形式的方法,并研究了吸附剂的破碎机理和失活原因;通过XPS和氩离子刻蚀XPS研究了S元素在吸附剂表面及其随深度的分布情况;利用原位XPS研究了待生剂中含S和含Ni物种在临氢条件下的转化行为,为吸附剂再生条件的选择提供支持。对铈离子改性Y分子筛,通过分析XPS定量结果和Ce(3d)化学态研究了铈离子在改性Y分子筛中笼内外的存在情况,结果表明液相法比固相法利于铈离子向分子筛内迁移。     

电子助进化学气相沉积金刚石中衬底温度对发射光谱的影响

采用蒙特卡罗方法,对以CH4/H2为源料气体的电子助进化学气相沉积(EACVD)金刚石中的氢原子(H_α,H_β和H_γ)、碳原子C(2p3s→2p2: λ=165.7 nm)以及CH(A2Δ→X2Π: λ=420～440 nm)的发射过程进行了模拟,研究了衬底温度对各发射谱线以及金刚石膜合成的影响。结果得知,各谱线强度随衬底温度的变化幅度很小,且在衬底表面附近的谱线强度随衬底温度的变化幅度相对于远离衬底的反应区域较大,这表明衬底温度的变化基本上不改变远离衬底的反应区域中反应基团成分,而只对衬底表面附近的反应过程有影响。由此得知,衬底温度对薄膜质量的决定性主要是由于衬底温度改变了衬底表面化学反应动力学过程和表面附近的反应基团的缘故,而不是衬底温度对反应空间中气相成分的影响。     

激光共振电离过程中铅同位素歧视效应研究

以速率方程为基础,通过数值模拟方法,对Pb的激光共振电离通道：“6s26p2 3P0—6s26p7s 3P0₁—电离”的激光诱导同位素歧视效应进行了研究,以探讨减小激光诱导歧视效应,准确测定Pb同位素比值的有效途径。通过考虑激光线型、原子吸收谱线线型、同位素位移及同位素超精细结构等因素的影响,对速率方程进行近似。在近似的速率方程基础上,以“1+1”激光共振电离过程为例,进而探讨激光峰值功率密度、带宽和中心波长对Pb的同位素歧视效应的影响。研究结果表明,利用最佳波长法,可基本消除同位素歧视效应的影响;提高激发光光强可使Pb同位素饱和电离,从而消除同位素歧视效应的影响;采用宽带激光激发,可减小同位素歧视效应的影响。     

傅里叶变换红外光谱在胃癌淋巴结转移诊断中的应用研究

观察傅里叶变换红外光谱技术无创、原位、快速诊断胃癌淋巴结转移的可行性。联合使用衰减全反射探头及傅里叶变换红外光谱仪测量新鲜离体胃周淋巴结红外光谱,发现每条光谱在吸收波长3 000～1 000 cm-1之间循序出现13条谱带,依据病理检测结果将淋巴结分为转移组及非转移组,比较两组淋巴结红外光谱的峰位和相对峰强等指标结果,最后进行标准统计学分析。36例胃癌患者,共检测淋巴结720枚,其中转移性淋巴结180枚,未转移540枚;与非转移淋巴结相比,转移淋巴结红外光谱有如下特征：(1)与核酸相关的峰强比I_{1 240}/I_{1 460}(p=0.015)和I_{1 080}/I_{1 460}(p=0.034)显著升高,提示转移淋巴结细胞的核酸含量增多;(2)与蛋白相关的I_{1 640}/I_{1 460}(p=0.001)和I_{1 546}/I_{1 460}(p=0.027)峰强比值升高,表明转移淋巴结组织的蛋白质含量明显升高;(3)与脂类相关的I_{2 855}/I_{1 460}和I_{1 740}/I_{1 460}显著降低(p＜0.001),提示癌组织脂类含量相对减少;(4)I_{1 160}/I_{1 460}(p=0.023)显著降低,表明恶性细胞糖类物质的减少。研究结果显示,傅里叶变换红外光谱分析技术有望成为术中原位、在体和快速诊断胃癌淋巴结转移的新方法。     

氮流量对磁控溅射法制备氮化钛薄膜光学性能的影响

采用磁控溅射方法在载波片和Al基片上制备了氮化钛薄膜;通过改变N2流量来改变薄膜中N／Ti原子比例。采用分光光度计和扫描隧道显微镜测试手段对氮化钛薄膜光学性能随N2流量变化的规律进行了研究。薄膜反射率光谱和扫描隧道图谱分析表明,氮化钛薄膜主要遵循自由载流子光吸收机制,随着N含量的增加,溥膜中的自由电子数目不断减少,等离子体频率逐渐红移,反射率降低,薄膜颜色发生变化。从薄膜扫描隧道谱（STS）可知,TiN薄膜表现出类似金属的光学性能,并且其禁带宽度Eg=1．64eV。     

Condensation Surface Temperature as a Means for Studying Film Formation Mechanisms

A rise in the condensation surface temperature during film growth is a result of energy dissipation on the condensation surface. An example of energy dissipation is the dissipation of chemical reaction heat, which releases during film deposition by reactive magnetron sputtering. The monitoring of the surface temperature during TiN film deposition by reactive (Ti–in–N₂) and nonreactive (TiN–in–Ar or TiN–in–N₂) sputtering methods has shown that this temperature is higher in the reactive case and decreases in the (TiN–in–Ar)–(TiN–in–N₂) sequence of nonreactive sputtering modifications. It has been found that the composition and crystal structure of TiN films do not depend on the growth method and are identical to those of bulk titanium nitride. Based on these results, a formation mechanism of films obtained by the above methods has been suggested. In the case of reactive sputtering, the film was supposed to grow on the condensation surface through a reaction between titanium and nitrogen atoms. In the cases of nonreactive sputtering, the film forms from TiN molecules.     

Deposition of TiN Films by Novel Filter Cathodic Arc Technique

A straight magnetic filtering arc source is used to deposit thin films of titanium nitride. The properties of the films depend strongly on the deposition process. TiN films can be deposited directly onto heated substrates in a nitrogen atmosphere or onto unbiased substrates by condensing the Ti^＋ ion beam in about 300 eV N2^＋ nitrogen ion bombardment. In the latter case, the film stoichiometry is varied from an N：Ti ratio of 0.6-1.1 by controlling the arrival rates of Ti and nitrogen ions. Meanwhile, simple models are used to describe the evolution of compressive stress as function of the arrival ratio and the composition of the ion-assisted TiN films.     

Synthesis of TiN/a-Si3N4 thin film by using a Mather type dense plasma focus system

A 2.3 kJ Mather type pulsed plasma focus device was used for the synthesis of a TiN/a-Si3N4 thin film at room temperature. The film was characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The XRD pattern confirms the growth of polycrystalline TiN thin film. The XPS results indicate that the synthesized film is non-stoichiometric and contains titanium nitride, silicon nitride, and a phase of silicon oxy-nitride. The SEM and AFM results reveal that the surface of the synthesized film is quite smooth with 0.59 nm roughness (root-mean-square).     

辉光放电等离子体辅助XeCl准分子激光溅射沉积碳氮薄膜

利用直流辉光放电等离子体辅助的脉冲激光沉积技术在Si衬底上生长了碳氮薄膜.通过扫描电子显微镜、X射线衍射、X射线光电子能谱、俄歇电子能谱等多种手段,对薄膜的形貌、成分、晶体结构、价键状态等特性进行了分析和确定.结果表明,沉积薄膜为含有非晶SiN和晶态氮化碳颗粒结构,晶态成分呈多晶态,主要为α-C₃N₄相、β-C₃N₄相,晶粒大小为40—60nm.碳氮之间主要以C-N非极性共价键形式相结合. 关键词： 脉冲激光沉积 直流辉光放电 碳氮薄膜     

TiN growth on Si by hybrid radical beam PLD

High-quality (good crystallinity and stoichiometry) titanium nitride (TiN) thin films were grown on Si(100) substrates by pulsed laser deposition (PLD) using a high-purity titanium target (99.99%) and nitrogen radical beam. The crystallinity, chemical composition, and depth profiles of the grown films were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Rutherford backscattering spectroscopy (RBS), respectively. The XRD pattern indicated that the preferred growth of TiN(200) with an orientation parallel to the Si(100) direction was obtained and the nitrogen radical drastically improved crystallinity compared with that grown in ambient nitrogen gas. RBS spectra indicated that the combination of PLD and the nitrogen radical beam suppressed silicidation at the interface between the Si substrate and TiN thin film during growth. The XPS analysis revealed that this method achieved the synthesis of stoichiometric TiN films.     

Microstructure and tribological properties of TiN, TiC and Ti(C, N) thin films prepared by closed-field unbalanced magnetron sputtering ion plating

TiN, TiC and Ti(C, N) films have been respectively prepared using closed-field unbalanced magnetron sputtering ion plating technology, with graphite target serving as the C supplier in an Ar-N₂ mixture gas. Bonding states and microstructure of the films are characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) in combination with transmission electron microscopy (TEM). The friction coefficients are measured by pin-on-disc test and the wear traces of deposited films are observed by optical microscope. Results show that the TiN film and Ti(C, N) film exhibit dense columnar structure while the TiC film exhibits a mixed microstructure of main nanocrystallite and little amorphous phases. The Ti(C, N) film has the highest microhardness value and the TiC film has the lowest. Because of small amount of pure carbon with sp² bonds existing in the film, the friction coefficients of Ti(C, N) and TiC multilayer films are lower than that of TiN film. In addition, the multilayer structure of films also contributes visually to decrease of friction coefficients. The TiC film has extremely low friction coefficient while the wear ratio is the highest in all of the films. The results also show that the Ti(C, N) film has excellent anti-abrasion property.     

添加Y改善离子镀氮化钛膜的结构与性能

评价了离子镀氮化钛(TiN)和Y改性氮化钛(Ti(Y)N)膜的结合强度和在酸性介质中的耐蚀性能;用X射线衍射,离子探针质谱分析(IMA),透射电子显微镜(TEM)研究它们的显微结构特征;结果表明,添加Y元素富集在Ti(Y)N与A₃钢基材界面区域,并形成厚度约为20nm的亚层,Y的界面改性导致Ti(Y)N膜的X射线衍射线形略有宽化和明显的TiN相(111)面的择优生长取向;这些显微结构特征的改善导致Ti(Y)N膜比TiN膜具有更高的界面结合强度和更好的耐蚀性能。 关键词：     

Development of novel titanium nitride-based decorative coatings by calcium addition

Calcium was added into titanium nitride coatings deposited using a hybrid magnetron sputtering-arc evaporation process. The calcium content in the films was adjusted by the variation of the pulsed DC current applied to the Ca sputtering target. X-ray diffraction analyses suggested that the increase of the calcium content induced the partial substitution of titanium atoms by calcium ones in the TiN lattice and a refinement of the grain size. Optical reflectance investigations showed that the absorption band of TiN was shifted towards higher wavelengths and that (Ti,Ca)N coatings may be suitable for decorative applications. Finally, the decrease of the film reflectivity was interpreted as a consequence of a free electron concentration decrease as confirmed from electrical resistivity measurements.