PBE聚合物紫外可见光谱及化学还原研究

合成了一系列 1,2_二 (N_取代_4_吡啶盐 )乙烯类聚合物 (简称PBE) ,研究了其紫外可见光谱性质及化学还原行为 .探讨了PBE在还原剂Na2 S2 O4 存在下发生不可逆氧化还原反应的还原机理 。

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.

Contacted Ion Pairs in Aqueous CuCl2 by the Combination of Ratio Spectra, Difference Spectra, Second Order Difference Spectra in the UV-Visible Spectra

The microstructure of aqueous CuCl2 has been studied through lots of technologies for many years; however, it remains a controversial subject. In this study, a new spectroscopic method has been proposed to analyze the UV-visible spectra of thin fihn of CuCl2/H2O solutions at different concentrations. This method is the combination of ratio spectra, difference spectra and second order difference spectra. By using this method, two new bands at -230 and -380 nm are obviously observed. The bands are assigned as the contacted ion pairs [CuCl3（H2O）n]- or [CuCl4（H2O）n]2-, which demonstrates that ion pairs exist in the CuCl2/H2O solution. Such finding agrees with the recent theoretical spectra obtained by time-dependent density functional theory. Furthermore, the populations of the contacted ion pairs are discussed. This study not only offers the direct spectroscopic evidence of [CuCl3（H2O）n]- or [CuCl4（H2O）n]2- in aqueous CuCl2, but also suggests that the spec- troscopic analysis method is powerful to extract the weak bands in a strong overlapping spectrum.

Identification of Superoxide O2^- during KNO3-NaNO2-NaNO3 Salt by Electron UV-Vis Absorption Spectroscopy Thermal Decomposition of Molten Paramagnetic Resonance and

On account of excellent thermal physical properties, molten nitrates/nitrites salt has been widely employed in heat transfer and thermal storage industry, especially in concentrated solar power system. The thermal stability study of molten nitrate/nitrite salt is of great importance for this system, and the decomposition mechanism is the most complicated part of it. The oxide species O2^2- and O2^- were considered as intermediates in molten KNO3-NaNO3 while hard to been detected in high temperature molten salt due to their trace concentration and low stability. In this work, the homemade in situ high temperature UV- Vis instrument and a commercial electron paramagnetic resonance were utilized to supply evidence for the formation of superoxide during a slow decomposition process of heat transfer salt （HTS, 53 wt% KNO3/40 wt% NaNO2/7 wt% NaNO3）. It is found that the superoxide is more easily generated from molten NaNO2 compared to NaNO3, and it has an absorption band at 420-440 nm in HTS which red shifts as temperature increases. The band is assigned to charge-transfer transition in NaO2 or KO2, responsible for the yellow color of the molten nitrate/nitrite salt. Furthermore, the UV absorption bands of molten NaNO2 and NANO3 are also obtained and compared with that of HTS.

A comprehensive analysis of various structural parameters of Indian coals with the aid of advanced analytical tools

An exhaustive structural analysis was carried out on three Indian coals （ranging from sub-bituminous to high volatile bituminous coal） using a range of advanced characterization tools. Detailed investigations were carded out using UV-Visible spectroscopy, X-ray diffraction, scanning electron microscopy coupled energy dispersive spectroscopy, Raman spectroscopy and Fourier transform infrared spectroscopy. The X-ray and Raman peaks were deconvoluted and analyzed in details. Coal crystallites possess turbostratic structure, whose crystallite diameter and height increase with rank. The tJdC ratio plotted against aromaticity exhibited a decreasing trend, confirming the graphitization of coal upon leaching. It is also found that, with the increase of coal rank, the dependency of I20/I26 on La is saturated, due to the increase in average size of sp2 nanoclusters. In Raman spectra, the observed G peak （1585 cm^-1） and the D2 band arises from graphitic lattices. In IR spectrum, two distinct peaks at 2850 and 2920 cm i are attributed to the symmetric and asymmetric -CH2 stretching vibrations. The intense peak at - 1620 cm^-1, is either attributed to the aromatic ring stretching of C=C nucleus.

UV enhanced gas–solid synthesis of chlorinated poly vinyl chloride characterized by a UV–Vis online analysis method

Dynamic characteristics of UV enhanced gas–solid PVC chlorination process were revealed by a UV–Vis spectral online analysis method. Experimental results showed an instantaneous increase of the chlorination rate as soon as UV light was affiliated, which demonstrated the intensified effect of UV radiation on PVC chlorination directly.Different affiliation methods of UV light were then studied, proving that continuous UV radiation could enhance the chlorination process significantly while intermittent UV radiation was able to initiate the chlorination reaction once it was conducted. Besides, experiments were carried out to study the influences of parameters on the chlorination process such as UV wavelength, chlorination temperature, partial pressure of chlorine gas and PVC raw materials. Among all the parameters, chlorination temperature and partial pressure of chlorine gas were testified as two key factors to determine the chlorination performance. Thermal analysis of CPVC products showed that their corresponding properties such as the glass transition temperature(Tg) and the homogeneity of chlorine distribution in polymer phase were improved with the increase of chlorine content.

Electric Conductivity Study of o-Substituted Phenoxo Iron （Ⅲ） Complexes

The coordination nature of a number of substituted sodiumphenoxides to iron （Ⅲ） ion has been studied. The o-nitrosodiumphenoxide was found to have different coordination behaviour from that the sodium salts of salicylic acid and methylsalicylate showed. The structure of the complexes, the number of the ligands being coordinated to the metal ion, has also been determined by titration, uv-vis spectroscopy, atomic absorption and the flame test. In addition, other sodium phenoxides were also involved in this study for comparison. An electric conductivity study on the resulting complexes was carried out and all complexes were found to be semiconductors.

Iron(Ⅱ) tetrasulfophthalocyanine mimetic enzymatic synthesis of conducting polyaniline in micellar system

Iron(Ⅱ) tetrasulfophthalocyanine(FeTSPc) ,as a novel mimetic enzyme of peroxidase,was used in the synthesis of a conducting polyaniline(PANI) /sodium dodecylsulfate(SDS) complex in SDS aqueous micellar solutions. The effects of pH,concentrations of aniline,SDS and H2O2,and reaction time on polymerization of aniline were studied in this case as shown by UV-Vis absorption spectroscopy. The results show that a wide range of pH(0.5-4.0) is required to produce the conducting PANI,and the optimal pH is 1.0 in SDS micelle. The optimal concentrations of aniline,SDS and H2O2 in feed,and reaction time in this case for the production of conducting PANI are respectively 10 mmol/L,10 mmol/L,25 mmol/L,and 15 h. FT-IR spectrum,elemental analysis,conductivity,cyclic voltammetry and thermogravimetric analysis confirm the thermal stability and electroactive form of PANI.

Spectroscopic Studies of the Interaction of Silver Nanoparticles with Methylene Blue

The interaction between silver nanoparticles and Methylene Blue （MB） is studied by UV-Vis spectroscopy and fluorescence spec- trometry. The UV-Vis absorption of the silver nanoparticles changes dramatically with the addition of MB. However, no obvious changes of absorption spectra of MB are observed when silver colloids are added into the MB solution. In the presence of surfactant SDS, the catalysis of the silver nanoparticles in the reduction of MB by sodium borohydride is exhibited by UV-Vis and fluorescence spectrosopy of MB displaying faster response compared with the absence of the silver nanoparticles. The results show that the activity of surfactant SDS modified silver nanoparticles is great and a strong physical adsorption to MB exists.

Adsorption properties of CFBC ash-cement pastes as compared with PCC fly ash-cement pastes

Circulating fluidized bed combustion （CFBC） ash can be potentially used as supplementary cementitious materials for concrete production due to its desirable pozzolanic activity. The adsorption properties of CFBC ash-cement pastes were studied, and ordinary pulverized coal combustion （PCC） fly ash-cement pastes were used as control. The water-adsorption and superplasticizer （SP）-adsorption properties of the pastes were evaluated by water demand and UV-visible absorption spectroscopy respectively. The results show that CFBC ash-cement system has greater compressive strength as compared with PCC fly ash-cement system at a given curing age, although the water demand of the former is significantly higher than that of the latter. CFBC ash-cement pastes possess higher adsorption ability of aliphatic SP than PCC fly ash-cement pastes and the adsorption amount increases with an increase in ash replacement ratio. CFBC ash- cement pastes exhibit lower workability with higher slump loss. It is concluded that CFBC ash can be potentially used as supplementary cementitious material in concrete production, but the mix design of CFBC ash concrete needs to be appropriately adjusted. It is suggested that CFBC ash is used for the production of the concrete needing low flowability.

UV-Vis Spectrophotometry and AFM Observation of Diethyl Dithiophosphate Adsorption on Chalcopyrite at Varied pHs

Adsorption of diehtyl dithiophosphate on chalcopyrite has been studied using UV-visible spectroscopy at pH values of 4, 6, and 9. It was found that the adsorption of diethyl dithiophosphate decreased with the increasing pH treatments. The inhibition of diethyl dithiophosphate adsorption was found prominent in higher pH as a result of metal hydroxide species formation onto chalcopyrite surface. First order kinetic has been proposed and represented the adsorption mechanism. Flotation test using Hallimond tube has also been conducted and the results were consistent with the proposed mechanism. Furthermore, the morphological changes of the treated chalcopyrite were observed using Atomic Force Microscopy （AFM） showing the propensity of growth of islands, the new surfaces as products of the reaction. The hydrophobicity was measured in the form of force of adhesion. The results resembled with the approached mechanism.

丙烯酸-2,4,6-三硝基苯乙酯的合成及热分解

以TNT、甲醛为原料,在弱碱性条件下反应合成得到2,4,6-三硝基苯乙醇(PicCH2CH2OH);PicCH2CH2OH在浓硫酸催化下和丙烯酸在甲苯中回流反应24h,合成得到丙烯酸-2,4,6-三硝基苯乙酯,产率为62%。采用紫外可见光谱(UV-Vis)、核磁共振氢谱(1HNMR)、红外光谱(FTIR)、质谱(MS)以及元素分析等对产物结构进行了表征。利用热重分析(TG)对产物热稳定性进行了研究,采用Kissinger方法和Ozawa方法计算其热分解活化能Ea分别为99.78,102.96kJ·mol-1。

Electrochemical Tuning by Polarized UV Light Induced Molecular Orientation of Chiral Salen-type Mn（II） and Co（II） Complexes in an Albumin Matrix

The authors have prepared supramolecular systems as artificial metalloproteins composed of several chiral salen-type Mn（II） and Co（II） complexes in a HSA （human serum albumin） matrix. The docking was discussed by UV-vis spectral changes and a ligand-protein docking simulation program. After linearly polarized UV light irradiation, that anisotropy of molecular orientation of the complexes increased was confirmed by polarized IR spectra. The authors have observed that the electrochemical behavior of the aligned complexes incorporating diphenyl groups in HSA can be tuned without UV radiation damage of HSA higher structures.

Optical Absorption and Refractive Index Study of Ti： Al2O3 Single Crystal

The optical absorption of Ti：Al2O3 single crystal has been measured at room temperature, in the wavelength region between 200 nm and 800 nm. The main absorption peaks at 491 nm and 562 nm, the weak infrared absorption band with a peak at 650 nm and the strong UV absorption band below 300 nm were observed. The refractive index is discussed by using Fresnel＇s equation. In particular, the Sellmeier equation was determined in the visible region by means on non-conventional method based on the measurement of refraction by using UV-visible spectroscopy. The refractive indices decreased from 3.71 to 1.28 with wavelength in the range 400-800 nm.

Gold （III） Complexes with Thiolactate and bis-（1,4-Sodiumthiolactate） Butane Ligands

The new ligand bis-（1,4-sodium thiolactate） butane （L）-O2CCH3S-（CH2）4SCHCH3CO2- has been prepared from the reaction of disodium salt of thiolactic acid and 1,4-dichlorobutane, while the disodium thiolactate was prepared instanteously through the reaction of thiolactic acid with NaOH. Mono and dinuclear complexes were obtained by direct reaction of the above ligands with H[AuCI4] in 1 ： 1, 2：1, 1：2, 2：2 and 3：1 ligands to metal molar ratio. The prepared complexes were characterized by elemental analysis, spectral studies FTIR （Fourier transform Infrared） and UV-Vis, magnetic measurement, conductivity measurement and IHNMR for the ligand （L） and some of the complexes. The conductance data indicate that the complexes of the formulas Na[Au（SCH3CHCOO）2], Na[Au（SCH3CHCOO）（OOCCHCH3SH）2] and [Au（L）]Cl are 1：1 electrolyte. Electronic spectra and magnetic moment values indicate the presence of square planner geometry around Au（III） ions.

Aroma Properties of Selected Local Spices of Akwa Ibom State of Nigeria

Some famous local spices were selected to determine their potentials in terms of their aroma and utilization. They included Tea Bush （Ocimum basilicum）, Guinea Black Pepper （Piper guineense）, African Pepper （Xylopia aethiopica）, Alden Tree （Tetrapleura tetraptera） and the African Meg Nut or Onion Tree （Blighia unijugata）. Essential oils were extracted from the samples and used for aroma absorption test in a uv-visible spectrometer V2.03. The intensity of aroma was indicated at some peak values of absorption at particular wavelengths. The compounds responsible for the aroma at this peak values were identified by matching their wavelengths with those of known compounds at similar wavelengths of absorption. Thus, a compound such as Quinoline that has hot strong aroma and little bleaching effect was proved to be present in Guinea black pepper ;at the wavelength of 313.0 nm. Benzene with hot strong aroma and flammable effect was also indicated in this spice at the wavelength of 253.0 rim. Proximate analysis carried out showed that these spices have high nutritive values. Some of them such as Guinea black pepper, African Nutmeg and Ethiopian （African） pepper had high ether extract of 20.01, 25.97 and 31.25 respectively, and could be regarded as oil seeds, they contain much of essential oils.

Adsorption of Cationic Laser Dye onto Polymer/Surfactant Complex Film

Fabrication of complex molecular films of organic materials is one of the most important issues in modern nanoscience and nanotechnology. Soft materials with flexible properties have been given much attention and can be obtained through bottom up processing from functional molecules, where self-assembly based on supramolecular chemistry and designed assembly have become crucial processes and technologies. In this work, we report the successful incorporation of cationic laser dye rhodamine 6G abbreviated as R6G into the pre-assembled polyelectrolyte/surfactant complex film onto quartz substrate by electrostatic adsorption technique. Poly（allylamine hydrochloride） （PAH） was used as polycation and sodium dodecyl sulphate （SDS） was used as anionic surfactant. UV-Vis absorption spectroscopic characterization reveals the formation of only H-type aggregates of R6G in their aqueous solution and both H- and J-type aggregates in PAH/SDS/R6G complex layer-bylayber films as well as the adsorption kinetics of R6G onto the complex films. The ratio of the absorbance intensity of two aggregated bands in PAH/SDS/R6G complex fihns is merely independent of the concentration range of the SDS solution used to fabricate PAH/SDS complex self-assembled films. Atomic force microscopy reveals the formation of R6G aggregates in PAH/SDS/R6G complex films.

Reaction Kinetics between Thiobases and Singlet Oxygen Studied by Direct Detection of the 1O2 Luminescence Decay

Thiobase derivatives have received important investigations due to their wide usage as phototherapeutic agents and their potential carcinogenic side effects as immunosuppressants. The substitution of oxygen atom by the sulfur atom makes the ultraviolet absorption of thiobases redshifted and absorbs UVA light (>300 nm), resulting in unusual high quantum yield of triplet state to generate the singlet oxygen (1O2) through photosensitization. As a type of reactive oxygen species, 1O2 is highly reactive toward thiobases. Herein, we report the measurements of reaction rate constants between di erent thiobases and 1O2 in different solvents through the direct detection of 1O2 luminescence decay kinetics at 1270 nm. The rate constants of thiouracils with 1O2 are five times smaller than that of thioguanine with 1O2, which suggests that thiopurines are more reactive than thiopyrimidines and thus less suitable to be a photosensitive drug on the application of photodynamic therapy. Additionally, the rate constants of thiobases and 1O2 were found to be obviously influenced by the solvent polarity. With the increase of solvent polarity, the rate constants of thiobases and 1O2 decrease.

Kinetics Study on Reaction between Dihydroartemisinic Acid and Singlet Oxygen: An Essential Step to Photochemical Synthesis of Artemisinin

Artemisinin is an excellent antimalarial drug widely used in clinical medicine.However,due to the limitation of natural source of artemisinin,the chemical synthesis of artemisinin has achieved substantial attention.Dihydroartemisinic acid is a key precursor for the synthesis of artemisinin.The reaction of dihydroartemisinic acid with singlet oxygen to form peroxide is a pivotal step in the photochemical preparation of artemisinin.Nevertheless,the reaction kinetics of dihydroartemisinic acid with singlet oxygen has not been investigated previously.Herein,we report the rate constants of the reaction between dihydroartemisinic acid and singlet oxygen.By directly detecting the luminescence decay kinetics of singlet oxygen at 1270 nm at room temperature,the reaction rate constants of singlet oxygen and dihydroartemisinic acid in different solvents are obtained to be 1.81×10^5(mol/L)^-1·s^-1 in CCl4,5.69×10^5(mol/L)^-1·s^-1 in CH3CN,and 3.27×10^6(mol/L)^-1·s^-1 in DMSO,respec-tively.It is found that the reaction rate constants of dihydroartemisinic acid with singlet oxygen increase as polarity of the solvent increases among the three solvents.These results provide fundamental knowledge to optimize experiment conditions of photochemical synthesis of artemisinin for improving the yields of artemisinin.

Study on the ultraviolet-visible spectral feature of tobacco leaves by pattern recognition

In order to differentiate regions, varieties, and parts of tobacco leaves, two pattern recognition methods through pattern classification modeling were developed based on the comprehensive information of ultraviolet-visible spectroscopy （UV-VIS） by employing one-way analysis of variance （ANOVA1） and wave range random combination （WRRC） technology from MATLAB. This proposed classification method has never been reported previously and the instrument and operation for this method is much more convenient and efficient than previous reported classification methods. The result of this paper demonstrated that the spectral features extracted by ANOVAI and WRRC methods could be used to differentiate tobacco leaves with different patterns. The ANOVAI method had a training recognition rate range of 75.00-87.50%,4 and a validation recognition rate range of 57.14-100%. The WRRC method had a training recognition rate range of 75.00-94.12% and a validation recognition rate range of 66.67-100%. The ANOVAI method is more convenient and efficient in model developing, while the WRRC method utilizes fewer model variables and is more robust.