Semi-quantitative analysis of the structural evolution of mesophase pitch-based carbon foams by Raman and FTIR spectroscopy

Graphitized carbon foams(GFms)were prepared using mesophase pitch(MP)as a raw material by foaming(450℃),pre-oxidation(320℃),carbonization(1000℃)and graphitization(2800℃).The differences in structure and properties of GFms prepared from different MP precursors pretreated by ball milling or liquid phase extraction were investigated and compared,and semi-quantitative calculations were conducted on the Raman and FTIR spectra of samples at each preparation stage.Semi-quantitat-ive spectroscopic analysis provided detailed information on the structure and chemical composition changes of the MP and GFm de-rived from it.Combined with microscopic observations,the change from precursor to GFm was analyzed.The results showed that ball milling concentrated the distribution of aromatic molecules in the pitch,which contributed to uniform foaming to give a GFm with a uniform pore distribution and good properties.Liquid phase extraction helped remove light components while retaining large aromatics to form graphitic planes with the largest average size during post-treatment to produce a GFm with the highest degree of graphitization and the fewest open pores,giving the best compression resistance(2.47 MPa),the highest thermal conductivity(64.47 W/(m·K))and the lowest electrical resistance(13.02μΩ·m).Characterization combining semi-quantitative spectroscopic ana-lysis with microscopic observations allowed us to control the preparation of the MP-derived GFms.

双重傅里叶变换红外椭偏光谱系统的研制

介绍一种新型红外椭圆偏振光谱实验系统。实验中采用了对光子能量和方位角作双傅里叶变换 ,及同步旋转检偏和起偏器 (RAP)的方法 ,根据傅里叶变换的四个余弦交流分量 ,计算相应的光学常数。经过对实验系统各误差来源的分析和纠正 ,提高了实验精度 ,使误差控制在 1%以内。测量了Au等样品的红外介电函数谱 ,并用德鲁得 (Drude)模型作拟合运算 ,获得了与理论计算相一致的结果。

Evidence of Casparian Strip in the Foliar Endodermis of Pinus bungeana

利用荧光显微镜对白皮松 (PinusbungeanaZucc.)针叶内皮层结构进行深入观察 ,确认内皮层径向壁和横向壁上具有能够激发荧光的带状结构 ;用纤维素酶和果胶酶对内皮层充分酶解分离后 ,首次从叶中得到类似于根部内皮层特有的网状结构 ;应用傅立叶变换红外光谱分光术 (FTIR)对网状结构进行化学成分鉴定 ,其吸收光谱的分析结果表明 ,针叶内皮层细胞壁带状结构部分含有木质素、木栓质、纤维素和细胞壁蛋白等 ,而这些成分与针叶维管组织的成分不尽相同。上述证据表明 ,白皮松针叶内皮层细胞壁具有与根部内皮层相似的凯氏带结构。

固定排放源CO_2排放检测方法综述

系统梳理了7种典型的固定排放源CO_2排放检测方法,基于不同学科,分为化学法、电化学法和物理光学法。详细介绍了各检测方法的发展背景、基本原理和执行标准,从仪器设备、检测过程、检测结果三方面作出比较。相比于传统的原理简单、操作简便的化学方法和在检测过程和结果上均有一定改进的电化学方法,非分散型红外光谱法在检测方式、响应速度、结果精准度方面均有更好的表现,是国际上统一认定的固定排放源CO_2排放检测方法。

液氨中油和有机物快速分析

研究了一种液氨中油和有机物的快速测定方法 ,采用不分光红外光谱法直接测定样品中的碳氢键含量 ,方法简便快速 ,测定结果与质量法基本一致 ,实验表明新方法准确度。

Isolation of a Prodigiosin-producing Strain and Analysis of It's Pigments

[Objective] The aim was to isolate a prodigiosin producing strain and study its pigment fractions.[Method] Red pigment-producing bacteria was identified by physiological and biochemical characteristics after isolation in plate.By using column chromatography and thin-layer chromatography,pigment fractions were separated and purified from the extractives of the strain after fermentation in flask,and then pigment fractions were analyzed via UV-Vis and LC/MS.[Result] A red pigment-producing Serratia marcescens strain NS-17 sampled from soil of Nanchang was isolated and identified.2 pigment fractions showing similar UV-Vis and LC/MS characters were separated and purified,the characters of fraction 1 were identical to those of prodigiosin,while fraction 2 showed a special UV-Vis absorption spectrum that had not been reported.[Conclusion] A prodigiosin-producing Serratia marcescens strain NS-17 and its 2 pigment fractions were isolated.

Detection of Broad Bean Diseases by Fourier Transform Infrared Spectroscopy Combined with Curve Fitting

Fourier transform infrared （FTIR） spectroscopy was used to study diseased leaves in broad bean. Results showed that the infrared spectra of different broad bean diseased leaves were similar, which were mainly made up of the vibrational absorption bands of protein,lipid and polysaccharide.There were minor differences in-cluding the spectral peak position, peak shape and the absorption intensity in the range of 1 800-1 300 cm-1. There were obvious differences among their second derivative spectra in the range of 1 800-1 300 cm-1. After the procedure of the Fourier self-deconvolution and curve fitting of health bean leaves and broad bean diseased leaves in the range of 1 700-1 500 cm-1, three sub-peaks were obtained at 1 550 cm-1 （protein amide Ⅱ band）, 1 605 cm-1 （lignin） and 1 650 cm-1 （protein amide I band）.The ratios of relative areas of the bands of amide Ⅱ, lignin, and amide I were 38.86%, 28.68% and 32.47% in the spectra of healthy leaves, respec-tively. It was distinguished from the diseased leaves （chocolate spot leaf： 15.42%, 42.98% and 41.61%, ring spot leaf：32.39%, 35.63% and 31.98%, rust leaf： 13.97%, 46.40% and 39.65%, yel owing leaf curl disease leaf： 24.01%,36.55% and 39.44%）. For sub-peak area ratios （A1 563/A1 605, A1 650/A1 605 and A1 563/A1 654）, those of four kinds of diseased leaves were smal er than that of healthy leaves, and there were also differences among four kinds of diseased leaves. The results proved that FTIR combining with curve fitting might be a potential y useful tool for detecting different kinds of broad bean diseases.

Enhanced plasmonic photocatalysis by SiO_2@Bi microspheres with hot-electron transportation channels via Bi–O–Si linkages

The semimetal Bi has received increasing interest as an alternative to noble metals for use in plasmonic photocatalysis. To enhance the photocatalytic efficiency of metallic Bi, Bi microspheres modified by SiO2 nanoparticles were fabricated by a facile method. Bi-O-Si bonds were formed between Bi and SiO2, and acted as a transportation channel for hot electrons. The SiO2@Bi microspheres exhibited an enhanced plasmon-mediated photocatalytic activity for the removal of NO in air under 280 nm light irradiation, as a result of the enlarged specific surface areas and the promotion of electron transfer via the Bi-O-Si bonds. The reaction mechanism of photocatalytic oxidation of NO by SiO2@Bi was revealed with electron spin resonance and in situ diffuse reflectance infrared Fourier transform spectroscopy experiments, and involved the chain reaction NO -> NO2 -> NO3- with center dot OH and center dot O-2(-) radicals as the main reactive species. The present work could provide new insights into the in-depth mechanistic understanding of Bi plasmonic photocatalysis and the design of high-performance Bi-based photocatalysts. (C) 2017, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Preparation,characterization and photocatalytic activity of sulfuric acid-modified titanium-bearing blast furnace slag

The feasibility of reducing Cr(VI)from the aqueous solution by sulfuric acid-modified titanium-bearing blast furnace slag(SATBBFS)as a photocatalyst was investigated.The photocatalysts were examined by X-ray diffraction(XRD),UV-vis diffuse reflectance spectra,thermogravimetric analysis(TG)and Fourier transform infrared spectroscopy(FTIR).The photocatalytic activities of the different catalysts were evaluated by the photocatalytic reduction of Cr(VI)under UV-vis light irradiation.The results show that the photocatalytic activities of SATBBFS catalysts are strongly dependent on CaTiO3-to-TiO2 mass ratio,adsorption capacity and surface acidity,and SATBBFS calcined at 400°C shows a higher photocatalytic activity compared with other catalysts.

双黄药在黄铁矿浮选中的作用:可溶性、吸附研究、Eh和FTIR测定

用溶解度测定、吸附试验、Eh测定和红外光谱分光光度法研究了黄药在黄铁矿表面上的吸附机理。用乙基黄药或戊基黄药作捕收剂 ,黄铁矿可在pH 3～ 6范围浮选 ,但是 ,在pH 4时其浮选回收率最大。在有或没有黄药存在时 ,研究了黄铁矿的溶解度与 pH和搅拌时间的关系。试验结果表明 ,在pH 3时 ,黄药的存在使黄铁矿的溶解度从 6 0·10 - 6提高到12 0·10 - 6(即从 10 - 3 mol/L提高到 2·10 - 3 mol/L)。黄原酸铁、双黄药和与黄药搅拌的黄铁矿的富里叶变换红外光谱(FTIR)结果表明 ,在黄铁矿表面上只测定出双黄药。吸附试验结果表明 ,在酸性介质中 ,黄铁矿表面上的双黄药吸附量最高 ,在中性溶液中黄铁矿对黄药的吸附量比碱性溶液中的高。电化学数据证明 ,黄药存在时 ,溶液中铁浓度提高 1倍是由于三价铁离子还原为二价铁离子以及黄药氧化成双黄药所致。黄铁矿表面上双黄药和羟基黄原酸盐络合物的形成是黄铁矿浮选的主要原因。

Structural and Infrared Spectroscopic Study on Solvation of Acetylene by Protonated Water Molecules

The effect of solvation on the conformation of acetylene has been studied by adding one water molecule at a time. Quantum chemical calculations of the n＋ （C2H2）（H2O）n （n=1-5） clusters indicate that the H2O molecules prefer to form the OH...Tr interaction rather than the CH...O interaction. This solvation motif is different from that of neutral （C2H2）（H2O）n （n=1-4） clusters, in which the H2O molecules prefer to form the CH...O and OH...C Hbonds. For the H＋（C2H2）（H2O）n cationic clusters, the first solvation shell consists of one ring structure with two OH...Tr H-bonds and three water molecules, which is completed at n=4. Simulated infrared spectra reveal that vibrational frequencies of OH... H-bonded O-H stretching afford a sensitive probe for exploring the solvation of acetylene by protonated water molecules. Infrared spectra of the H＋ （C2H2）（H2O）n （n=1-5） clusters could be readily measured by the infrared photodissociation technique and thus provide useful information for the understanding of solvation processes.

Time-resolved infrared spectroscopic investigation of Ga_(2)O_(3) photocatalysts loaded with Cr_(2)O_(3)-Rh cocatalysts for photocatalytic water splitting

Investigation of the charge dynamics and roles of cocatalysts is crucial for understanding the reaction of photocatalytic water splitting on semiconductor photocatalysts.In this work,the dynamics of photogenerated electrons in Ga_(2)O_(3) loaded with Cr_(2)O_(3)-Rh cocatalysts was studied using time-resolved mid-infrared spectroscopy.The structure of these Cr_(2)O_(3)-Rh cocatalysts was identified with high-resolution transmission electron microscopy and CO adsorption Fourier-transform infrared spectroscopy,as Rh particles partly covered with Cr_(2)O_(3).The decay dynamics of photogenerated electrons reveals that only the electrons trapped by the Rh particles efficiently participate in the H2 evolution reaction.The loaded Cr_(2)O_(3) promotes electron transfer from Ga_(2)O_(3) to Rh,which accelerates the electron-consuming reaction for H2 evolution.Based on these observations,a photocatalytic water-splitting mechanism for Cr_(2)O_(3)-Rh/Ga_(2)O_(3) photocatalysts has been proposed.The elucidation of the roles of the Cr_(2)O_(3)-Rh cocatalysts aids in further understanding the reaction mechanisms of photocatalytic water splitting and guiding the development of improved photocatalysts.

Infrared Photodisssociation Spectroscopy of Boron Carbonyl Cation Complexes

The boron carbonyl cation complexes B（CO）3＋, B（CO）4＋ and B2（CO）4＋ are studied by infrared photodissociation spectroscopy and theoretical calculations. The B（CO）4＋ ions are characterized to be very weakly bound complexes involving a B（CO）3＋ core ion, which is predicted to have a planar D3h structure with the central boron retaining the most favorable 8-electron configuration. The B2（C0）4＋ cation is determined to have a planar D2h structure involving a B-B one and half bond. The analysis of the B-CO interactions with the EDA- NOCV method indicates that the OC→B cr donation is stronger than the B-＋CO π back donation in both ions.

Polarization Dependent Time-Resolved Infrared Spectroscopy and Its Applications

Polarization dependent time-resolved infrared （TRIR） spectroscopy has proven to be a useful technique to study the structural dynamics in a photochemical process. The angular information of transient species is obtainable in this measurement, which makes it a valuable technique for the investigation of electron distribution, molecular structure, and conformational dynamics. In this review, we briefly introduce the principles and applications of polarization dependent TRIR spectroscopy. We mainly focused on the following topics： （i） an overview of TRIR spectroscopy, （ii） principles of TRIR spectroscopy and its advantages compared to the other ultrafast techniques, （iii） examples that use polarization dependent TRIR spectroscopy to probe a variety of cheinical and dynamical phenomena including protein conformational dynamics, excited state electron localization, and photoisomerization, （iv） the limitations and prospects of TRIR spectroscopy.

The relationship between IR characteristic peak and microstructure of the glass used as optical fiber

Based on the harmonic vibration equation, the relationship between IR characteristic peak of fiberglass and Si-O-Si bond angle was deduced, and 1 100 cm^-1 characteristic peak was specifically studied. It is found that 1 100 cm^-1 characteristic peak shifts to higher wave number when Si-O-Si bond angle increases. Taking fused biconical taper （FBT） coupler as an example, the microstructures of the fiber coupler manufactured at different draw- ing speeds were tested with micro infrared spectrum. According to the test results, it is found that the bond angle at the taper region is the largest, the one at the fused region is the second largest, and the one of bare fiber is the smal- lest. The characteristic peaks of fused-taper region shift to higher wave number when drawing speed increases.

Effect and mechanism of siderite on reverse anionic flotation of quartz from hematite

Reverse flotation technology is one of the most efficient ways to improve the quality and reduce impurity of iron concentrate. Mineral processors dealing with hematite face a challenge that the flotation results of reverse flotation of hematite are poor in presence of siderite using fatty acid as collector, starch as depressant of iron minerals and calcium ion as activator of quartz at strong alkaline pH. In this work, the effect of siderite on reverse anionic flotation of quartz from hematite was investigated. The effect mechanism of siderite on reverse flotation of hematite was studied by solution chemistry, ultraviolet spectrophotometry(UV) and Fourier transform infrared spectroscopy(FTIR). It was observed that siderite had strong depressive effect on quartz in flotation using sodium oleate as collector, corn starch as depressant of iron minerals and calcium chloride as activator of quartz at strong alkaline pH. The starch was adsorbed onto calcium carbonate by chemical reaction which was formed by CO^(2-)_3 from siderite dissolution and Ca^(2+) from calcium chloride as activator of quartz and precipitated on the surface of quartz, which resulted in improving the hydrophilic ability of quartz.

Experimental Consideration of Two-Dimensional Fourier Transform Spectroscopy

Two-dimensional Fourier transform(2D FT) spectroscopy is an important technology that developed in recent decades and has many advantages over other ultrafast spectroscopy methods. Although 2D FT spectroscopy provides great opportunities for studying various complex systems, the experimental implementation and theoretical description of 2D FT spectroscopy measurement still face many challenges, which limits their wide application.Recently, the 2D FT spectroscopy reaches maturity due to many new developments which greatly reduces the technical barrier in the experimental implementation of the 2D FT spectrometer. There have been several different approaches developed for the optical design of the 2D FT spectrometer, each with its own advantages and limitations. Thus, a procedure to help an experimentalist to build a 2D FT spectroscopy experimental apparatus is needed.This tutorial review is intending to provide an accessible introduction for a beginner to build a 2D FT spectrometer.

Effect of Mn(II) on quartz flotation using dodecylamine as collector

Quartz is, in most cases, the major gangue mineral found in the manganese ore. Mn iron, dissolved from the surface of ore, will determine the interfacial properties of the particles and, thus, their flotation behavior. In this work, the effect of Mn2+ on quartz flotation was investigated through flotation tests. It was found that quartz can be depressed with Mn2+ and floated with dodecylamine in the pH region 7-8. In order to prove the validity of the findings, UV spectrophotometry, FTIR and SEM-EDS were carried out. UV spectrophotometry tests results show that Mn2+ can competitive adsorb with RNH3+ in the surface of quartz at acidic and neutral pH values. The FTIR measurements and SEM-EDS analysis indicate that Mn2+ forms precipitation and adsorbs on the negatively charged quartz surface, it induces quartz recovery dropping in alkaline pH. Furthermore, in the case of sodium hexametaphosphate(SH), sodium silicate or citric acid, the effects of Mn2+ were also studied. This depression in the given Mn2+ did not disappear. Citric acid is an appropriate modifier to separate quartz depressed by Mn2+ from other ores at pH 7.

Photoionization and Dissociative Photoionization Study of Cholesterol by I R Laser Desorption/Tunable Synchrotron VUV Photoionization Mass Spectrometry

Elementary cholesterol was analyzed with IR laser desorption/tunable synchrotron vacuum ultraviolet photoionization mass spectrometry. An exclusive molecular ion of cholesterol is observed by near threshold single-photon ionization with high efficiency. Fragments are yielded with the increase of photon energy. The structures of various fragments are determined with commercial electron ionization time-of-flight mass spectrometry. Dominant fragmentation pathways are discussed in detail with the aid of ab initio calculations.