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971.
Ge_2Sb_2Te_5 film was deposited by RF magnetron sputtering on Si (100) substrate. The structure of amorphous and crystalline Ge_2Sb_2Te_5 thin films was investigated using XRD, Raman spectra and XPS. XRD measurements revealed the existence of two different crystalline phases, which has a FCC structure and a hexagonal structure, respectively. The broad peak in the Raman spectra of amorphous Ge_2Sb_2Te_5 film is due to the amorphous -Te--Te- stretching. As the annealing temperature increases, the broad peak separates into two peaks, which indicates that the heteropolar bond in GeTe_4 and the Sb-Sb bond are connected with four Te atoms, and other units such as (TeSb) Sb-Sb (Te_2) and (Sb_2) Sb-Sb (Te_2), where some of the four Te atoms in the above formula are replaced by Sb atoms, remain in crystalline Ge_2Sb_2Te_5 thin film. And from the results of Raman spectra and XPS, higher the annealing temperature, more Te atoms bond to Ge atoms and more Sb atoms substitute Te in (Te_2) Sb-Sb (Te_2). 相似文献
972.
X-ray photoelectron spectroscopy (XPS) and laser Raman scattering (LRS) techniques have been employed to investigate the structure of amorphous (CuI)0.45–(Ag2WO4)0.55 solid electrolyte sample. XPS results reveal the presence of both Cu+ and Cu2+ ions whereas tungsten is found to exist only in the oxidation state of +6. The deconvolution of the O 1s spectrum into non-bridging and bridging oxygen atoms in conjunction with the laser Raman analysis tend to show that the amorphous (CuI)0.45–(Ag2WO4)0.55 solid electrolyte sample is composed mostly of octahedral WO6 units that probably form [W4O16]8− tetramer clusters, the existence of which is unique in the case of oxyhalide glasses. 相似文献
973.
用激光拉曼光谱研究了PTFE在室温下的压致相变,压致Ⅳ-Ⅱ和Ⅱ-Ⅲ相变时,相应的拉曼光谱都有明显的变化,讨论了压致相变时的构象变化.用Tait方程和Murnaghan方程处理等温压缩数据,也发现了Ⅱ-Ⅲ压致相变.首次计算了高压相的模Gruneisen参数. 相似文献
974.
F.S. Manciu R.E. Tallman B.D. McCombe B.A. Weinstein D.W. Lucey Y. Sahoo P.N. Prasad 《Physica E: Low-dimensional Systems and Nanostructures》2005,26(1-4):14
We use infrared (IR) and Raman spectroscopies to investigate the optically active phonon modes in InP nanoparticles and InP/II–VI core-shell nanoparticles fabricated by similar colloidal chemistry methods. The IR transmission spectra of several InP nanoparticle samples exhibit a common absorption feature, which we assign to the Fröhlich mode. The Raman results for the same samples show transverse and longitudinal optical phonon peaks, and scattering strength in between due to surface optical (SO) modes. Infrared spectra of the InP/ZnSe core-shell nanoparticles () exhibit three absorption features, one due to the InP core, and the others associated with the ZnSe shell layer. Raman measurements (12–292 K) also show three phonon-related peaks, whose intensities vary sharply with temperature. The frequencies of the IR and Raman lines are in approximate accord with dielectric continuum theory. 相似文献
975.
The low temperature glass transition occurring at low temperature in polyethylene samples was studied using Fourier transform infrared, FT‐Raman spectroscopic techniques, which are known to be sensitive to any structural changes in the investigated samples. Anomalous behavior was obtained in the temperature range (98 K → 383 K) indicating the existence of phase transition occurring at about 98 K and disappearing at about 323 K while heating for unirradiated virgin low density polyethylene (VPE) sample with or without crosslinking agent (trimethylol propane triacrylate, TMPTA). Addition of TMPTA monomer caused severe changes in the temperature dependence of both unirradiated and irradiated polyethylene samples. The results given indicated the occurrence of abnormal temperature dependence, which is thought to be related with low temperature structural change resulting from local crosslinking in scrapped polyethylene (SPE) sample already suffering from high degree of crosslinking. Differential scanning calorimetry (DSC) thermograms confirmed the observed new phase transition observed in both unirradiated and irradiated TMPTA loaded VPE/SPE (50/50 wt %) blend. Irradiation, addition of TMPTA as a crosslinking agent, and blending VPE with SPE were found to affect remarkably the variation of the vibration spectrum of LDPE and consequently the resulting structural changes. The experimental results obtained were discussed and correlated with reorientational disorders of the molecular segments (local crosslinking). © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 850–859, 2007 相似文献
976.
四种D-氨基葡萄糖甘氨酸混配金属配合物与DNA作用的SERS光谱研究 总被引:1,自引:0,他引:1
研究了四种D-氨基葡萄糖甘氨酸混配金属配合物的表面增强喇曼光谱(SERS),发现它们在银胶上的吸附方式基本相同,因而SERS光谱也基本相似,并用SERS光谱研究了它们与DNA的相互作用,发现这四种化合物与DNA的作用能力有很大不同,Co(Ⅲ)GluG是值得进一步研究的可能抗癌药物。 相似文献
977.
Tsutomu Sato 《Pramana》1983,21(6):375-384
The first-order Raman spectra ofE
gandA
1g
modes in MnF2 crystal were measured at temperatures from 4.2 to 563 K, and the values of the linewidths obtained. The temperature dependence
of the linewidths was analyzed by the phonon dispersion curves based on the rigid ion model, and the result showed that it
was caused approximately by the cubic anharmonic term in crystal potential energy. 相似文献
978.
Kuzbass State Technical University, 28 Vesennyaya Str., Kemerovo, 650026, Russia. Translated from Zhurnal Prikladnoi Spektroskopii,
Vol. 62, No. 6, pp. 58–61, November–December, 1995. 相似文献
979.
V. V. Berdyugin P. P. Shorygin K. Ya. Burshtein Yu. V. Korshak M. A. Tlenkopachev A. V. Orlov 《Russian Chemical Bulletin》1996,45(8):1912-1916
Specific features of the excitation spectra of resonance Raman (RR) lines in multimode systems were characterized. Based on this, the spectra, the structure, and the composition of polyacetylene (PA) synthesized by polymerization of cycloocta-1,3,5,7-tetraene in the presence of metathesis catalysts were investigated. A dependence of frequencies and intensities of the C-C and C=C stretching lines on the exciting light wavelength was found and explained by broad distribution of defect-free conjugated polymer segments in the PA samples studied on the number of double bonds incorporated in them. A procedure for the calculation of the distribution functions and of the shapes of RR lines was proposed. These functions are bimodal. A reversiblecis-trans-transition was discovered in the PA samples not subjected to heat treatment, which was attributed to the presence of macrocyclic polyene structures.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 2016–2020, August, 1996. 相似文献
980.
分布光纤喇曼光子传感器系统的一种解调方法 总被引:11,自引:1,他引:10
本文提出一种新的解调方法,在DOFRPS(分布光纤喇曼光子传感器)系统中采用Rayleigh散射OTDR(光学时域反射)曲线解调Raman散射OTDR曲线,提高了系统的测温灵敏度、测温精度,扩展了系统的功能,在2km光纤上可实时测量1000个点的温度、应力和压力;在系统中设置了光纤取样环,确定系统的修正系数,通过计算机进行实时修正,提高了测量稳定性,实验结果与理论分析一致,系统的测温精度达±1℃。 相似文献