不同地区八角莲的红外光谱分析

利用光谱学在不同样品中的特征吸收为基础,建立红外光谱学对不同产地的中药材快速鉴定方法,从而实现快速鉴别不同产地的同种中药材提供可高的依据。利用八角莲各种成分对红外光谱的吸收特征峰为基础,对5个不同产地的八角莲进行光谱照射,比较各产地八角莲的红外光谱特征峰,并寻找其差异。结果表明:不同产地八角莲药材红外光谱特征吸收峰的二阶导数图,表现出较为明显的差异,除了黔南布依族苗族自治州长顺县的八角莲在1400.32cm-1处没有吸收峰以外,其他四个地区的八角莲在此处均有吸收。广西桂林的八角莲在1200~1000cm-1范围内有5个吸收峰,而云南昆明的在此范围内只有3个吸收峰;四川凉山自治州冕宁县的八角莲在原图中就可以看出其C-O的伸缩振动吸收峰比较弱,且在1200~1000cm-1范围内只有两个吸收峰。梵净山的八角莲在此范围内的吸收峰最多,共有10个;原谱图中3143.97cm-1及1400.32cm-1峰的吸收峰基本不受其他成分的影响。因此,建立的红外光谱技术可以为不同地区八角莲药材的鉴别提供一种简便快捷的方法。     

萘普生及其中间体的红外光谱和核磁共振谱分析

对萘普生及其合成中间体的红外光谱和氢核磁共振谱进行分析 ,归属了几种重要的红外吸收峰和氢峰。     

萘普生及其中间体的红外光谱和核磁共振谱分析

对萘普生及其合成中间体的红外光谱和氢核磁共振谱进行分析,归属了几种重要的红外吸收峰和氢峰。     

耐候试验对中空玻璃密封胶红外光谱的影响

采用高湿、高低温、气候和紫外辐照4种条件进行中空玻璃密封胶耐候试验。采用衰减全反射（ATR）法测试耐候试验前后密封胶的红外光谱，分析不同试验条件对中空玻璃硅酮胶、聚硫胶和聚氨酯胶红外光谱的影响。研究结果表明：4种条件耐候试验后，中空玻璃密封胶的红外光谱吸收峰位置均没有明显变化；高湿试验后，红外吸收峰强度降低，其中硅酮胶降低最明显；高低温试验后，红外光谱基本没有变化；气候试验和紫外辐照试验后，硅酮胶的红外光谱没有变化，聚硫胶主要吸收峰强度明显降低，聚氨酯胶除1 407 cm-1附近吸收峰强度降低外，其他吸收峰强度均有所增强。耐候试验后密封胶的红外光谱变化表明，3种密封胶耐高低温性能均优异，耐湿性能硅酮胶最差、聚氨酯胶最好，耐紫外辐照性能硅酮胶最好、聚硫胶最差。     

十种大米的红外光谱分析

通过红外光谱(FTIR)技术和其二阶导数分析技术,对十种大米的整体红外特征吸收峰进行分析。结果表明,十种大米的一维红外光谱的峰形、峰位及峰的强度具有相似性,而其二阶导数谱图的差异较为显著,反映在蛋白质、氨基酸、糖等成分特征吸收峰上的差异,这与稻米的品种、种植环境及加工工艺有关。该方法快速、简捷,为食品品质的评价提供了理论依据。     

浅谈影响红外吸收光谱强度的因素

在解析红外光谱时,要同时注意红外吸收峰的位置,强度和峰形。然而,在确定化合物分子结构时,必须将吸收峰位置辅以吸收峰强度和峰形来综合分析,可是这后两个要素往往得不到应有的重视。     

红外光谱法区分不同激光打印机墨粉

利用傅立叶变换红外光谱法对6种不同品牌的激光打印机墨粉进行种类分析,确定了墨粉中添加的树脂成分。同时还对同一品牌的7种不同型号的激光打印机墨粉进行了红外光谱特征峰及谱峰细节特征研究,通过比对各样品中红外光谱吸收峰的差异,达到区分不同墨粉的目的。     

氟橡胶粘结耐热炸药界面作用的红外光谱分析

用傅立叶红外光谱(FT-IR)研究了由氟橡胶包覆几种耐热炸药的界面作用。实验发现在氟橡胶的作用下耐热炸药供电子基团的吸收峰均产生位移，这说明氟橡胶与耐热炸药界面存在相互作用。主体炸药的分子结构不同，界面上各基团相互作用的强弱不同，产生吸收峰位移的方向也不同。     

FTIR-ATR在橡胶配比鉴定中的应用

红外光谱技术是利用物质分子对红外辐射的吸收,得到与分子结构相应的红外光谱图,从而来鉴别出分子结构的方法。本文采用FTIR-ATR技术,对SIR、CIIR、SIR/CIIR、NR、NR/CIIR以及两种面具罩体材料进行谱峰分析,根据红外谱图的峰位、峰形及峰强等参数,鉴定各种橡胶的成分。     

食用油品质的红外吸收光谱分析

测定了8种食用油的红外吸收光谱并进行比较分析.结果表明,不同食用油在4000～500cm-1范围内的红外吸收光谱基本相同,在3009,2925,2854,1746,1464,1377,1163,722cm-1处均出现相似的吸收峰,说明不同种类的食用油的主要成分是相同的.各种食用油红外吸收光谱特征峰的相对强度又有所不同,...     

Influence of Dose on Particle Size and Optical Properties of Colloidal Platinum Nanoparticles

Attempts to produce colloidal platinum nanoparticles by using steady absorption spectra with various chemical-based reduction methods often resulted in the fast disappearance of the absorption maxima leaving reduced platinum nanoparticles with little information on their optical properties. We synthesized colloidal platinum nanoparticles in an aqueous solution of polyvinyl pyrrolidone by gamma radiolytic reduction method, which produced steady absorption spectra of fully reduced and highly pure platinum nanoparticles free from by-product impurities or reducing agent contamination. The average particle size was found to be in the range of 3.4–5.3 nm and decreased with increasing dose due to the domination of nucleation over ion association in the formation of metal nanoparticles by the gamma radiolytic reduction method. The platinum nanoparticles exhibit optical absorption spectra with two absorption peaks centered at about 216 and 264 nm and the peaks blue shifted to lower wavelengths with decreasing particle size. The absorption spectra of platinum nanoparticles were also calculated using quantum mechanical treatment and coincidently a good agreement was obtained between the calculated and measured absorption peaks at various particle sizes. This indicates that the 216 and 264-nm absorption peaks of platinum nanoparticles conceivably originated from the intra-band transitions of conduction electrons of (n = 5, l = 2) and (n = 6, l = 0) energy states respectively to higher energy states. The absorption energies, i.e., conduction band energies of platinum nanoparticles derived from the absorption peaks increased with increasing dose and decreased with increasing particle size.     

不同产地、不同种属黄精的红外光谱鉴别研究

采用傅里叶红外光谱技术结合二阶导数光谱对不同产地的黄精进行鉴别。研究结果表明,不同产地多花黄精的红外光谱图在整体上比较相似,其主要吸收峰均在3270、2933、1623、1411、1372、1319、1269、1103、1019、926、865、815 cm-1附近,但吸收峰的位置、峰强度等方面存在明显差异,在1018 cm-1附近是糖类的特征吸收峰,由红外光谱图可推测安徽省池州市、岳西县、江西省宜春市多花黄精中糖类成分含量较高,湖北省黄冈市、安徽省黄山区、石台县次之,安徽省休宁县、金寨县相对较少。6种黄精属植物的红外光谱图在吸收峰的位置、形状、强度等方面均有差异,故可推测黄精属不同植物在化学成分及含量上均存在明显差异。二阶导数图呈现出许多原始图谱中被掩盖的谱峰的变化特征,将谱图间的差异更为明显得表现出来,进一步提高了谱图的分辨率,与普通红外光谱图相比,二阶导数红外光谱图进一步直观地验证了上述结果。     

Raman spectroscopy of mesophase pitches

Raman spectra have been measured for mesophase pitches prepared from different starting materials. The spectra exhibited the two major absorption peaks characteristic of other carbonaceous materials. The relative intensities of these peaks have been related to molecular size and to the degree of order in the mesophase. A comparison of Raman data for carbonaceous materials shows that the absorption frequency of the longer wavelength band is related to the degree of graphitization.     

Terahertz absorption spectra of Fatty acids and their analogues

Absorption spectra in the terahertz (THz) region between 10 and 400 cm(-1) were measured for fatty acids and their analogues at room temperature. Saturated fatty acids such as palmitic and stearic acids had some sharp peaks, while unsaturated fatty acids such as oleic, linoleic and linolenic acids had two distinct peaks at 247 and 328 cm(-1). These peaks apparently derived from the carboxylic group because oleyl alcohol had no distinct peak. The THz absorption spectra of fatty acids may be affected by the crystalline as well as the chemical structure. The THz absorption spectra of oleic acid esters depended on ester types, although all oleic acid esters had some peaks due to the ester group. THz absorbance of fatty acids positively correlated with concentration. Based on these results, THz spectrometry may be a good analytical method for the non-destructive qualitative and quantitative evaluation of fatty acids and their analogues.     

Optical excitations of finite carbon nanotubes

Optical excitations of finite carbon nanotubes by the cross polarized light are studied within the gradient approximation. They are dominated by the quantum size effects. The absorption spectra exhibit rich absorption peaks, mainly owing to many zero-dimensional discrete states. They strongly depend on the length, the radius, the chiral angles, and the magnetic flux. The absorption peaks gradually group together as the length increases. The threshold excitation energy (ω_th) decreases in the increasing of radius. The dependence of ω_th on length is monotonous for zigzag nanotubes, while it is oscillatory for armchair nanotubes. The threshold excitation energy is constant for the sufficiently long carbon nanotubes. Chiral carbon nanotubes exhibit very complicated optical spectra, compared with achiral carbon nanotubes. The magnetic flux reduces the threshold excitation energy and increases the number of absorption peaks.     

苯酚的紫外光谱研究

苯酚是一种应用很广的化工原料,对生物体以及环境危害很大.苯酚是环境监测的一项重要指标,因而对其性能的研究就显得非常重要.文章主要研究苯酚在不同的溶剂中的紫外光谱.结果发现,苯酚的两个强吸收峰在碱性溶液中会发生红移,分别从210 nm红移至234 nm;270nm红移至287 nm,而在酸性溶液中则无明显变化,溶剂极性对...     

二茂铁甲酸原位接枝环氧化端羟基聚丁二烯的合成研究

选用四丁基溴化铵作相转移催化剂,进行二茂铁甲酸(FcCA)接枝环氧化端羟基聚丁二烯(EHTPB)的合成研究.合成产物的红外光谱和1H-NMR显示,在1714和1276 cm-1处表现出明显的羧酸酯基团特征吸收峰,在1139和823 cm-1处表现出茂环特征吸收峰,在4.2～4.9处显示茂环上9H的核磁共振谱带.化学分析...     

Ultraviolet Spectral Analysis of Polyvinyl (Butyral) Film Incorporating 10,12-Pentacosadiynoic Acid Monomer for Application in Radiation-Processing Dosimetry

A detailed study was performed to investigate the dosimetric characteristics of polyvinyl butyral containing 10,12-pentacosadiynoic acid (PCDA) monomer. PCDA monomer undergoes polymerization upon γ-ray exposure, inducing change in the absorption spectra in the UV region of the spectrum. The unirradiated film has four absorption peaks at 216, 227, 241, and 256 nm. Upon irradiation, two new peaks at 271 and 286 nm are developed and their amplitudes with the original peaks increase with increasing absorbed dose. The useful dose range is 3-100 kGy depending on PCDA monomer concentration. The expanded uncertainties (2σ) associated with dose measurement were estimated.     

Photoacoustic Spectroscopy of Some Energetic Materials

To find an effective laser source to ignite energetic materials, the absorption spectra of some energetic materials are obtained by means of a photoacoustic spectroscopy (PAS). In this experiment, PAS covers the wavelength region of 400 nm-1600 nm in which no other conventional method can take absorption spectra for powdered energetic materials. Photoacoustic spectra of 18 energetic materials are reported. In general, energetic materials tested showed peaks in 600 nm–800 nm and 1400 nm–1600 nm ranges. It is found that the energy required to initiate explosives in the case of ruby laser initiation were correlated with their photoacoustic signal intensities.     

Derivative ultraviolet and visible spectrophotometry: Applications to polymer analysis

First- to fourth-derivative spectra of humic acids, polystyrene, and mixtures of several prepolymers were measured and the advantage of derivative spectrophotometry such as resolution enhancement and background correction was discussed. Although the vis-absorption spectra for humic acids in pH solutions from pH 2.0 to 10.0 could be hardly discriminated, humic acids in solutions above pH 7.0 could be clearly distinguished from those in solutions below pH 6.0 by first-derivative spectrophotometry. Similarly, the first-derivative spectra of the copper-humic acid complex were different from those of free humic acids, though both absorption spectra resembled each other. UV absorption spectrum of a mixture of phenol-novolac resin and methylated methylol-melamine resin was similar to and the second-derivative spectrum was different from that of phenol-novolac resin. The difference of derivative spectra of a mixture of polycarbonate and epoxy resin was also discussed. Shoulder and unresolved peaks were clearly revealed by differentiation of absorption spectra and peak assignments from the fourth-derivative spectra were more accurate than those from the absorption spectra. This advantage was discussed by using polystyrene as an example.