FCVA制备超薄类金刚石薄膜的拉曼光谱分析

采用FCVA方法制备厚度分别为50nm、30nm、10nm、5nm、2nm的DLC薄膜,利用可见光拉曼光谱分析薄膜的G峰位置、Id/g和Ag/Ad,发现随着薄膜厚度的减小,Id/Ig不断增大,AgAd减小,G峰位置向低波数方向移动.紫外拉曼光谱分析结果表明,薄膜厚度减薄会减小It/Lg使T峰位置向高波数方向移动.结合两种不同波长的拉曼光谱进行分析,G峰偏移量随薄膜厚度减小呈下降趋势;随薄膜厚度的减小,FCVA法制备的类金刚石薄膜中的sp3键含量减少,同时有序化的sp2团簇增加.EELS结果也证实,薄膜厚度的减小会减少薄膜中sp3键的含量.对于50nm和30nm的非晶碳膜,拉曼光谱分析的结果与薄膜硬度和内应力实际测试结果存在一致的对应关系.     

高碳钢盘条氧化皮的激光拉曼光谱分析

采用激光拉曼光谱并结合SEM和XRD等手段对高碳钢盘条表面氧化皮进行了研究,同时,对不同冷却条件下形成的氧化皮机械剥离性能进行了评价。结果表明,氧化皮为三层结构,控冷条件下形成的氧化皮机械剥离性能良好,而炉冷条件下形成的氧化皮经机械剥离后仍有一层Fe3O4残留。     

中国对虾部分基因组文库构建和微卫星DNA序列的筛选

以中国对虾为实验材料,提取肌肉的基因组DNA。经Bsp143Ⅰ酶切后,回收500～1000bp的DNA片段,与经BamHⅠ酶切并去磷酸化的PUC19重组,将重组载体转入大肠杆菌DH5α中。然后将其涂布于含氨苄青霉素的LB平板上,过夜培养后,经蓝白斑筛选,构建对虾部分基因组文库。采用载体质粒的通用引物进行PCR检测插入片段的大小,对基因组文库进一步进行筛选。从建立的文库中选取100个片段大小合适的克隆进行测序,其中54个克隆的DNA插入片段含有微卫星序列,共获得了111个微卫星序列,在GenBank中注册了12个微卫星序列。本实验中还发现1个含有23bp的小卫星序列。     

金属铀热氧化腐蚀的红外和拉曼光谱分析

为了进一步认识金属铀环境腐蚀的规律,采用傅里叶变换红外和显微激光拉曼光谱技术,获得了金属铀与空气热氧化反应产物的红外和拉曼光谱图.实验结果表明,随着温度的升高,铀表面首先出现活性腐蚀亮斑,并逐渐积累长大,主要氧化产物UO2在260℃以上开始转化为U3O8.同时,200℃以上温度条件下,铀表面的热氧化腐蚀速率明显高于较低温度时的氧化反应.研究结果将为改善防腐措施、提高核燃料的安全可靠性提供有价值的参考信息.     

吲哚类合成大麻素的差分拉曼光谱分析

建立一种简便快速、准确可靠、无损检材的检验合成大麻素类新精神活性物质的方法-差分拉曼光谱法。利用手持式差分拉曼光谱仪,在激光光源785 nm,激光功率200 mW,积分时间1 s,扫描范围为2 400～200 cm–1的条件下,对17种吲哚类合成大麻素标准品进行检验。首先对样本进行人工分类,利用系统聚类法将17个样本分为4组,与人工分类结果较为一致。再运用Fisher判别分析构建4个判别函数对样本分类结果进行验证,准确率为94.1%。可以根据差分拉曼光谱的数据对17种合成大麻素类物质进行区分。利用该方法可以对吲哚类合成大麻素进行快速无损的检验,并可用于公安机关实际办案。     

基于化学计量学对药品铝塑包装片的差分拉曼光谱分析

目的 为快速无损地检验犯罪案件现场遗留的药品铝塑包装片。方法 采用最新的差分拉曼光谱仪,并基于化学计量学对收集的51个药品铝塑片样本进行分析。结果 共对收集的药品铝塑包装片样本提取出了9个有效光谱成分因子,累积占原始光谱数据99.54%的有效信息,并将51个样本分为4大类,通过相关性比较,可知分类结果较好。结论 实验方法简便,无损检材重现性实验结果较好,为药品铝塑包装片类物证的检验提供依据,可为公安工作的开展提供有效帮助。     

溶胶-凝胶法制超细炭的拉曼光谱和XRD研究

采用不同的原料 ,利用溶胶 -凝胶超临界流体干燥法制得了超细炭原粉。将超细炭原粉在氩气气氛中于1 1 0 0℃和 2 60 0℃分别进行炭化和石墨化处理得到超细炭粉。利用 XRD和拉曼光谱对超细炭粉进行了表征。研究结果表明 ,原料性能对超细炭结构有较大的影响。     

不同厚度四面体非晶碳薄膜的拉曼表征和内应力

为了探讨膜厚对四面体非晶碳薄膜拉曼结构表征和内应力的影响规律，进而确定应力与拉曼光谱之间的关系，采用过滤阴极真空电弧技术以相同的工艺条件在P（100）单晶抛光硅衬底上制备了从3nm～350nm不同厚度的四面体非晶碳薄膜。利用表面轮廓仪和原子力显微镜测试膜厚，表面轮廓仪确定曲率半径并计算薄膜应力，共聚焦拉曼光谱表征薄膜的结构细节。实验发现，随着膜厚的增加，四面体非晶碳薄膜的应力持续下降，当膜厚超过30nlll时，应力的下降趋势变得平缓，并保持在小于5GPa的较低水平。随着膜厚的增加，可见光拉曼光谱中衬底硅的一阶和二阶谱峰强度逐渐降低，在50nm～80nm膜厚范围，半高宽最窄，峰强最高，能够最有效地获得拉曼结构信息。随着膜厚的增加和应力的下降，非晶碳一阶谱峰的峰位表现为逐渐向低频偏移。     

聚丙烯腈基碳纤维石墨化程度对其电阻率的影响

以市面常见的6种碳纤维发热电缆为实验材料,利用拉曼光谱技术对实验材料的石墨化程度进行表征,利用数字源表(吉时利2400型)测定每组样品的电阻,以得到样品的电阻率。结果表明:当碳纤维的石墨化程度越高时,其电阻率越低。这是因为石墨化程度越高时,碳纤维成分中石墨碳的含量越高,与此同时碳纤维中非晶态过渡碳结构的芳环共轭程度增加,使π电子的迁移能力增强。随着碳纤维石墨化程度的增加,六元碳层面内的碳碳键距离增大,共价电子向传导电子转移,禁带变小,导带增大。另外,石墨化程度的增加意味着在碳纤维内部石墨的取向越来越好,故而致使电阻率降低。     

在不同时间下退火对非晶硅薄膜晶化的影响

用玻璃作衬底在不同温度下用PECVD法直接沉积非晶硅(a-Si∶H)薄膜,在400℃和500℃分别光退火5min、10min、20min、30min、40min、60min、120min,用拉曼光谱分析前后样品,发现随着晶化时间的延长晶化效果越好,500℃退火的薄膜比400℃的晶化效果好.     

木质陶瓷的X射线衍射和喇曼光谱研究

采用X射线衍射和激光喇曼光谱, 研究了以烟杆和酚醛树脂为原料制备木质陶瓷炭化过程中结构的变化特征. 研究结果表明, 炭化温度的升高可以使木质陶瓷XRD谱图中衍射峰增加, 强度增大, 同时木质陶瓷中石墨微晶的平均层间距d₀₀₂减小, 堆积厚度L _c增加, 微晶直径 L _a在973K出现转折点; 木质陶瓷的喇曼光谱图为典型的类石墨炭材料的喇曼谱图, 只出现了表征无序结构的D线和表征石墨结构的G线, 且表征无序化度的二者积分强度比R值随炭化温度的升高先增后减, 而根据Tuinstra-Koenig 经验式计算得到的微晶直径L a值表现出与R值相反的规律; 两种分析方法的结果较为一致, 均表明木质陶瓷结构在973K发生根本改变, 说明喇曼光谱有望成为木质陶瓷结构的快速测试方法.     

Raman Spectroscopy and SEM Study of SWNTs in Aqueous Solution and Films with Surfactant or Polymer Surroundings

Raman spectra of single-walled carbon nanotubes (SWNTs) in aqueous solutions with sodium dodecylsulfate (SDS) or fragmented single-stranded DNA (ss-DNA) and films obtained from these solutions have been studied. Scanning electron microscope (SEM) film study shows that micelles formed by SDS molecules around SWNT in solution do not keep individual nanotubes from sticking together in bundles during drying out the film. DNA wrapped around SWNT precludes the full nanotubes sticking in the film that facilitates the following splitting of these bundles.     

电沉积与铁基体电位活化的增强拉曼光谱研究

为探讨电沉积初始过程对电镀层结合强度的影响,采用循环伏安法和表面增强拉曼(SERS)光谱研究了光亮铁电极在5%KCl溶液中表面氧化物随电位负移的还原过程,并应用循环伏安法和恒电流电位-时间法研究了氰化物镀铜体系铁基体的电位活化现象和电沉积初始过程.结果表明,在电位-0.9 V时,特征波数为424 cm-1和499 cm-1的Fe3O4谱峰消失,电位-1.2 V时,特征波数671 cm-1的FeO、谱峰明显降低,说明Fe3O4和FeO在不同电位下依次实现还原过程.循环伏安曲线在-0.9 V及-1.2 V附近也依次出现了铁氧化物的还原电流平阶.在氰化物镀液中,铜的析出电位(约-1.4 V)负于铁表面氧化物的还原电位,电极过程首先实现铁表面氧化物的还原,随后铜沉积在活化的铁基体上.     

Raman Spectroscopy, Structural Modifications, and Phase Transitions in the High-Temperature Superconductors

The formation of phases is investigated from a systematic study of the Raman active phonons in the whole range of oxygen doping of YBa₂Cu₃O _x (6 < x < 7). Changes in the spectral characteristics of the in-phase vibrations of the plane oxygen atoms in the overdoped region are related, with slight modifications of the buckling in the CuO₂ planes. A softening of the A _g symmetry apical oxygen phonon is accompanied with an increase in the intensity of the high-frequency mode at 600 cm^–1 and attributed to the breaking of the chains into small segments. The analysis of the apex and the in-phase phonon modes indicates the formation of superstructures, which are embedded as spatially separated phases in the whole oxygen concentration region of 6.35 < x < 6.95. A similar separation into small domains of phases may also occur in the underdoped compounds (x < 6.35) down to a critical oxygen concentration at x 6.15, where the system breaks into randomly oriented small chains.     

Quantitative enhanced Raman scattering of labeled DNA from gold and silver nanoparticles

Surface-enhanced resonance Raman scattering (SERRS) from silver nanoparticles using 514.5-nm excitation has been shown to offer huge potential for applications in highly sensitive multiplexed DNA assays. If the technique is to be applied to real biological samples and integrated with other methods, then the use of gold nanoparticles and longer wavelengths of excitation are desirable. The data presented here demonstrate that dye-labeled oligonucleotide sequences can be directly detected by SERRS using gold nanoparticles in a quantitative manner for the first time. The performance of gold and silver nanoparticles as SERRS substrates was assessed using 514.5-, 632.8-, and 785-nm excitation and a range of 13 commercially available dye-labeled oligonucleotides. The quantitative response allowed the limit of detection to be determined for each case and demonstrates that the technique is highly effective, sensitive, and versatile. The possibility of excitation at multiple wavelengths further enhances the multiplexing potential of the technique. The importance of effectively combining the optical properties of the nanoparticle and the dye label is demonstrated. For example, at 632.8-nm excitation, the dye BODIPY TR-X and gold nanoparticles make a strong SERRS combination with very little background fluorescence. This study allows the choice of nanoparticle and dye label for particular experimental setups, and significantly expands the applicability of enhanced Raman scattering for use in many disciplines.     

Analysis of Strain and Stress in Ceramic,Polymer and Metal Matrix Composites by Raman Spectroscopy

Raman scattering is a unique tool providing information on the structure and short‐range order of matter. Stress‐induced Raman shifts can be used to determine the stress/strain in films, fibres, particulate composites and, more generally, in any phase a few microns or more in scale. Quantitative results follow from a wavenumber calibration as a function of tensile strains or pressures applied to reference fibres or crystals. Furthermore, if the material is coloured, (near) resonant Raman scattering occurs, which enhances the scattered light intensity and simplifies the spectra – especially for harmonics – but drastically reduces the analysed volume (in‐depth penetration ∼10–100 nm). This paper discusses the effective and potential advantages/drawbacks of Raman micro‐spectrometry technique. The procedures to improve the sensitivity, the legibility and the reliability will be addressed. Examples will be chosen among (aramid, C, SiC) fibre‐ reinforced ceramic (CMCs), polymer (PMCs) or metal matrix (MMCs) composites.     

Optical Absorption and Raman Spectroscopy Study of the Fluorinated Double-Wall Carbon Nanotubes

Double-wall carbon nanotube (DWNT) samples have been fluorinated at room temperature with varied concentration of a fluorinating agent BrF₃. Content of the products estimated from X-ray photoelectron data was equal to CF_0.20 and CF_0.29 in the case of deficit and excess of BrF₃. Raman spectroscopy showed considerable decrease of carbon nanotube amount in the fluorinated samples. Analysis of optical absorption spectra measured for pristine and fluorinated DWNT samples revealed a selectivity of carbon nanotube fluorination. Nanotubes with large chiral angle are more inert to the fluorinating agent used.