12-硅钨酸与γ-Al2O3载体表面的相互作用

研究了不同溶剂中的ＳｉＷ１２在γ－Ａｌ２Ｏ３表面的吸附和溶脱规律，以ＩＲ，ＸＲＤ以及酸催化模型探针反应对吸附于γＡｌ２Ｏ３表面的ＳｉＷ１２的存在形态和酸性进行了表征。尽管ＳｉＷ１２碱降解稳定性在常见杂多酸中最强，但由水溶液中吸附在γ－Ａｌ２Ｏ３表面的ＳｉＷ１２仍有一部分被该载体的碱性所降解，此外，在γ－Ａｌ２Ｏ３表面上ＳｉＷ１２质子活性性大大减弱，其阴离子的热稳定性也明显降低了可以认为，ＳｉＷ１２     

12－硅钨酸与γ－Al_2O_3载体表面的相互作用

研究了不同溶剂中ＳｉＷ１２在γ－Ａｌ２Ｏ３表面的吸附和溶脱规律，以ＩＲ，ＸＲＤ以及酸催化模型探针反应对吸附于γ－Ａｌ２Ｏ３表面的ＳｉＷ１２的存在形态和酸性进行了表征．尽管ＳｉＷ１２碱降解稳定性在常见杂多酸中最强，但由水溶液中吸附在γ－Ａｌ２Ｏ３表面的ＳｉＷ１２仍有一部分被该载体的碱性所降解．此外，在γ－Ａｌ２Ｏ３表面上ＳｉＷ１２质子的活动性大大减弱，其阴离子的热稳定性也明显降低．可以认为，ＳｉＷ１２的质子和Ｋｅｇｇｉｎ阴离子与γ－Ａｌ２Ｏ３表面均有直接相互作用．     

TiO2负载膜的制备、表征及光催化性能

采用溶胶－凝胶法制备了ＴｉＯ２纳米浸渍 法将其负载于颗粒形活性炭的表面制成ＴｉＯ２负载,利用ＳＥＭ,ＥＤＳ和ＸＲＤ等手段对膜的形貌、均匀性及晶型等进行了表征,并通过甲基橙水溶液的光催化降解反应考察了该负载膜的光催化活性。     

纳米TiO2光催化降解苯酚的动力学研究

以１２５Ｗ高压汞灯为光源,以ＴｉＯ２为催化剂,对不同初始浓度的苯酚水溶液进行了光催化降解实验。同时,考察了不同溶液ｐＨ值时的光催化行为。根据实验结果,提出了与文献报道不同的ＴｉＯ２光催化降解苯酚的零级反应动力学模型。     

TiO2薄膜光催化降解4-(2-吡啶偶氮)间苯二酚的研究

为了探索有机物４－（２－吡啶偶氮）间苯二酚（ＰＡＲ）,在固定光催化剂上的降解行为,采用溶胶一凝胶法,在玻璃表面制得均匀透明的纳米ＴｉＯ２薄膜,并以其作光催化剂,在２５４ｎｍ紫外光照射下,进行ＰＡＲ水溶液的光催化降解研究。研究了ＰＡＲ光催化降解率与溶液ｐＨ值、ＰＡＲ初始浓度、助催化剂（Ｈ２Ｏ２）浓度和不同光照条件的变化关系,得出了ＴｉＯ２薄膜的光催化降解ＰＡＲ的有利条件。     

V2O5/高硅分子筛的酸性与甲苯气相选择氧化

用固体离子交换法制备了Ｖ２Ｏ５／ＺＳＭ－５和Ｖ２Ｏ５／丝光沸石两类催化剂。通过ＸＲＤ，ＬＲＳ，ＸＰＳ和Ｓｇ测定表征了Ｖ２Ｏ５在分子筛上的分散状态。用吡啶吸附红外光谱法和正丁胺非水溶液回滴法研究了催化剂的表面酸性。用ＥＳＲ研究了甲苯在催化剂上的吸附。结果表明，催化剂的酸性不同，它们吸附甲苯的能力也不同，对甲苯气相选择氧化的活性和选择性也有较大的差异。同时，甲苯选择氧化成苯甲醛的能力还与Ｖ２Ｏ５在分子     

电沉积烧结ZrO2—8wt%Y2O3薄膜及其对AISI304不锈钢高温氧化行…

在水溶液中于ＡＩＳＩ３０４不锈钢表面电沉积Ｚｒ（ＯＨ）４－Ｙ（ＯＨ）３薄膜，然后在３００￣５００℃烧结形成ＺｒＯ２－８ｗｔ％Ｙ２Ｏ３薄膜，讨论了相应的机理。研究结果表明，表面沉积ＺｒＯ－８ｗｔ％Ｙ２Ｏ３薄膜的试样与空白试样相比，氧化增重下降约３倍，表面沉积ＺｒＯ２－８ｗｔ％Ｙ２Ｏ３薄膜有益作用在于改善了氧化膜与不锈钢基体的附着力和促进铬的选择性氧化。     

不同添加物和制备方式对Al2O3热稳定性的影响

通过水溶液成胶和丙三醇络事助成胶制备了不同的结构的γ－Ａｌ２Ｏ３,研究了Ｌａ,Ｓｉ,Ｂａ以及Ｌａ,Ｓｉ和Ｌａ,Ｂａ双组分改性对它们结构热稳定的作用,讨论了改性元素的引入方式及硅铝比的影响。结果表明,丙三醇络合助成胶能明显提高Ａｌ２Ｏ３的比表面积和孔径,并能显著改善Ａｌ２Ｏ３的热稳定性。     

悬浮粒子对电沉积Zn粉缓蚀性能的影响

在ＺｎＣｌ２镀槽中悬浮一定量的不溶性粒子，如石墨ＰｂＣ２，ＳｎＯ２，ＴｉＯ２，ＳｉＯ２等，电沉积制备Ｚｎ粉，并对其结构，形貌及腐蚀行为进行分析，ＳＥＭ的结果表明使用悬浮法可阻止Ｚｎ枝晶生长，悬浮ＰｂＯ２，ＳｎＯ２，ＴｉＯ２，ＳｉＯ２或Ｉｎ２Ｏ３等能明显地提高Ｚｎ粉在５ｍｏｌ／ＬＫＯＨ溶液中的缓蚀能力此外，文中还应用于分形理论对结果作了进一步讨论。     

低温降解二氯甲烷的TiO_2－SO_4~（2－）催化剂研究

研制了硫酸化氧化钛催化剂（表示为ＴｉＯ_２－ＳＯ_４~（２－）），实验表明在低于３００℃的反应温度下，它能有效地降解二氯甲烷（浓度为４２．８μｍｏｌ／Ｌ），如在２７５℃，二氯甲烷的转化率达１００％，降解产物为ＣＯ、ＣＯ_２和ＨＣｌ．该催化剂含２％硫酸根，氨的吸附量为每克催化剂３．４ｍｍｏｌ．与未经硫酸化处理的ＴｉＯ_２对比，硫酸化后的催化活性显著提高，表明二氯甲烷降解反应发生在固体酸的酸性活性中心上．水汽的存在明显降低了催化活性，提高了反应活化能．在ＴｉＯ_２－ＳＯ_４~（２－）上负载ＣｕＯ后可显著提高降解产物中二氧化碳的选择性．     

Application of Alizarine Derivatives as Chromogenic Reagents for the Spectrophotometric Determination of Some Sulfa Drugs

A spectrophotometric procedure for the determination of six pharmaceutical sulfonamides containing a primary aromatic amino group using alizarine (I), alizarine blue (II), alizarine red (III), and quinalizarine (IV), that offers advantages of simplicity, rapidity, sensitivity, precision, and stability, has been developed. The proposed method is based on the formation of colored products with the chromogenic reagents (I-IV). A linear correlation was found between absorbance at λ_max and the concentration. For more accurate results, Ringbom optimum concentration ranges are evaluated. The molar absorptivities (ε), absorptivities (a), and Sandell sensitivities for all sulfonamides derivatives with the chromogenic reagents tested were calculated. The procedures developed are applied for bulk sulfa drugs and some of their dosage forms.     

Kinetics of the alizarine red S surface redox reaction

Kinetics of the surface redox reaction of alizarine red S adsorbed on mercury is measured by square-wave voltammetry. In 1 mol/l KNO₃ buffered to pH 9.22, the standard reaction rate constant of the redox couple anthraquinone/anthrahydroquinone in the adsorbed alizarine red S molecule is k_s=100 ±10 s^-1 and the cathodic transfer coefficient is =0.4. At pH 2 in this medium k_s is greater than 500 s^-1.     

Study on the Bleaching Mechanism of Indigo—carmine Catalyzed by Laccase Using EFA and MCR—ALS Methods

The bleaching of indigo-carmine catalyzed by laccase was monitored on-line by UV/Vis spectroscopy.The resulted data were analyzed by evolving factor analysis(EFA) and multivariate curve resolution(MCR),and the reaction mechanism was proposed.     

Suppression of Delayed-type Hypersensitivity and Hemolysis Induced by Previously Photooxidized Psoralen: Effect of Fluence Rate and Psoralen Concentration

Abstract— The kinetics of the formation of biologically active psoralen photooxidation (POP) products were analyzed by the biological effects produced. Effects of the UV light fluence rate and psoralen concentration during the preir-radiation were investigated to assess the yield of POP products, which were active in vivo (inducing suppression of delayed-type hypersensitivity [DTH] reaction to sheep red blood cells) and in vitro (altering the human erythrocyte membrane permeability). It was shown that the reciprocity law of the irradiation fluence rate and time was not valid in the case of POP-induced hemolysis and DTH suppression. Immunosuppressive POP products were more efficiently formed at low fluence rate (20.8 W/m²), whereas POP hemolysins were more efficiently produced at a high fluence rate (180 W/m²) of UV light. The yield of immunosuppressive POP products was enhanced in dilute psoralen solutions, while the POP hemolysins yield increased with increasing psoralen concentration. A kinetic scheme for psoralen photoproduct formation was proposed. Kinetic analysis showed that a labile intermediate was produced as the result of excitation of psoralen. This intermediate was either converted to a stable immunosuppressive POP product, or two intermediates combined to form a POP hemolysin. It is proposed that PUVA therapy conditions are more favorable for the formation of immunosuppressive rather than membrane-damaging psoralen photooxidation products.     

Investigation of the acid-base properties of mononitro-calix[4]arene with chemometric methods

The acid-base properties of mononitro-calix[4]arene was studied with chemometric methods by measurement of its UV absorbance under different pH. The chemometric method-iterative target transformation factor (ITTFA) was employed to resolve the acid-base fraction curves. Combining with other chemometric methods-principal component analysis (PCA) and evolving factor analysis (EFA), the proton dissociation behavior of the derivative was investigated in detail. The pK(a) values of the derivative were determined and the fraction curves and pure absorbing spectra of each absorbing component were obtained.     

化学计量学方法解析苯胺电解过程

在对混合物样品的紫外可见光谱测量数据阵矩进行主成分分析、潜变量投影等方法解析后,得到一种物质的光谱曲线和另一种物质的动力学曲线,这在化学计量学意义上是一类比较特殊的黑色体系.提出了一种解析这个难题的算法,并详细论证了方法中不可避免的唯一解问题.对于模拟数据,解析结果证明本算法的正确性.用本法解析了苯胺水溶液电解过程,得到苯胺和中间物的动力学曲线及其纯光谱.     

Evaluating UV-B effects and EDU protection in soybean leaves using fluorescence

A growth-chamber experiment was conducted to evaluate whether ethylenenediurea (EDU), a chemical shown to be protective against ozone pollution, could ameliorate foliar damage induced by ultraviolet-B (UV-B) radiation exposure in 'Roanoke' soybean (Glycine max L.), a UV-B-sensitive cultivar, and whether these effects could be discriminated using fluorescence (F) observations. The experiment had four treatment groups: control; biologically effective UV-B (18 kJ m(-2) day(-1)); EDU (500 micromol mol(-1)); and both UV-B and EDU (UV/EDU). Measurements included photosynthetic pigments, F image system (FIS) images of adaxial surfaces in four spectral regions (blue, green, red and far-red) and F emission spectra of the pigment extracts produced at two excitation wavelengths, 280 nm (280EX) and 380 nm (380EX). Several F ratios from 280EX, 380EX and the FIS images successfully separated the low UV vs high EDU group responses based on means alone, with intermediate values for controls and the combined UV/EDU groups. A UV-B/blue emission ratio, F315/F420 (280EX), was correlated with chlorophyll content (microg cm(-2))(R = 0.88, P < 0.001), as was a ratio of emissions at two UV-A wavelengths: F330/F385 (280EX) (R = 0.87). These two 280EX ratios were also linearly correlated with emission ratios produced by 380EX, such as the far-red/green ratio, F730/F525 (380EX) (R = 0.92, P < 0.001), and clearly distinguished the UV-B and EDU groups separately, and which bracketed the similar intermediate responses of the UV/EDU and control groups. The FIS images additionally captured the following anatomical spatial patterns across the leaf surfaces: (1) emissions of UV-B-irradiated leaves were more uniform but lower in intensity than those of other groups; and (2) emissions of EDU-treated leaves exhibited the greatest variation in spatial patterns because veins had elevated blue F and leaf edges had enhanced red and far-red F. This experiment supports the hypothesis that EDU substantially ameliorated UV-B damage to foliage, a result that relied on the combined use of FIS images and emission spectra.     

Electrochemical Sensor Based on Multiwalled Carbon Nanotube,Alizarine Red S and Chitosan for Simultaneous Determination of Oxomemazine Hydrochloride,Paracetamol and Guaifenesin

A simple and highly sensitive sensor has been used for the determination of oxomemazine hydrochloride (OXO) in presence of paracetamol (PAR) and guaifenesin (GU). Carbon paste electrode was modified with multiwalled carbon nanotube (MWCNT), alizarine red S (AZ) and chitosan (CH). Scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to characterize the nanostructure and performance of the sensor. Under the optimized experimental conditions OXO gave linear response over the range of 2.00×10⁻⁶–1.00×10⁻⁴ mol L⁻¹. The detection limit was found to be 4.35×10⁻⁷ mol L⁻¹. The practical application of the modified electrode was demonstrated by measuring the concentration of OXO in pharmaceutical samples and urine. This revealed that suggested sensor shows excellent analytical performance for the determination of OXO in terms of a very low detection limit, high sensitivity and selectivity.     

Bioaccumulation and biotransformation of flavonols by erythrocytes

A model for the complete system of bioaccumulation, transport, and biotransformation of polyphenolic compounds (flavonols) that includes hemoglobin-containing red blood cells and serum albumin was proposed. The distribution of flavonols between the erythrocyte fraction and albumin was studied. Hemoglobin was shown to play a role in the biotransformation of flavonols. The formation of several intermediate and final products of pseudoperoxidase oxidation of flavonols catalyzed by methemoglobin was established by UV spectrophotometry and RP-HPLC. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 153-157, March-April, 2009.     

EFFECTS OF PHOTOSYSTEM II INHIBITORS ON ELECTRON PARAMAGNETIC RESONANCE SIGNAL II OF SPINACH CHLOROPLASTS

Abstract— In isolated spinach chloroplasts the light-induced electron paramagnetic resonance signal (signal II) associated with the oxygen evolving photosystem (photosystem II) decays slowly and incompletely in the dark. Tris-washing, hydroxylamine, or carbonylcyanide m -chlorophenylhydrazone (CCCP) enhance the decay of signal II, which can still be induced by red (645 nm) but not by far-red (735 nm) radiation. Although 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) alone has no effect on signal II, it blocks the induction of signal II in the presence of hydroxylamine or CCCP. These data suggest that signal II is an indicator of an oxidized intermediate on the water-splitting side of photosystem II.