Alkaline treatment of the cellulose fiber affecting membrane column behaviour for high-performance immunoaffinity chromatography

The original cellulose fibers and those treated by alkaline solution were both used to prepare the acrylic membranes. The two kinds of membranes were packed into the columns for high-performance immunoaffinity chromatography by the immobilization of protein A on them. It was observed that the alkaline treatment of the cellulose fiber decreased the pressure resistance of the membrane to the mobile phases and greatly increased the accessible volume to the proteins, but affected the adsorption capacity of human IgG on the protein A membrane columns less. There is little difference between those two kinds of membranes on the adsorption capacities of HIgG, which means that the alkaline treatment of the cellulose fiber only significantly changes the void volume inter-membrane, and the porosity and surface area of membrane less. Alkaline treatment of the cellulose fiber reduced the membrane-column efficiency significantly. Some typical examples for the immunoaffinity analysis of IgG from human and dog plasma on the protein A membrane columns are illustrated. Copyright (C) 2000 John Wiley & Sons, Ltd.

Cobalt boride catalysts for hydrogen generation from alkaline NaBH4 solution

Cobalt boride precursors were synthesized via chemical reaction of aqueous sodium borohydride with cobalt chloride, and followed by heat-treating at various temperatures. The as-prepared Co-B catalysts were characterized and analyzed by X-ray diffraction (XRD), nitrogen adsorption-desorption and catalytic activity test; and were adopted to help accelerating hydrolysis reaction of NaBH4 alkaline solution. The Co-B catalyst treated at 500 degrees C exhibits the best catalytic activity, and achieves an average H, generation rate of 2970 ml/min/g, which may give a successive H, supply for a 481 W proton exchange membrane fuel cell (PEMFC) at 100% H-2 utilization. (c) 2005 Elsevier B.V. All rights reserved.

Electrochemical Impedance Spectroscopy Of Peo Coating On Aluminum Alloy In Nacl Solution

Various Plasma Electrolytic Oxidation (PEO) ceramic coatings were prepared on LY12 aluminum alloy by adjusting the concentration of sodium silicate solution. Optical microscope (OM), XRD and EIS were used to study their morphology, composition and anti corrosion behavior in NaCl solution. Increasing concentration of sodium silicate leads to the increase of the total coating thickness while too high and too low concentration lead to the decrease of inner dense layer. The main composition of PEO coatings prepared in 20, 40 and above 60g/L concentration solution are correspondingly alumina, alumina with mullite, and amorphous phase. The corrosion resistance is determined by the inner dense layer. Increasing the thickness of inner dense layer can improve the anti-corrosion performance. PEO coating's corrosion resistance in acidic, alkaline and neutral NaCl solution is proved and the corrosion mechanism involved is also discussed.

Release of Sulfur and Chlorine during Cofiring RDF and Coal in an Internally Circulating Fluidized Bed

An internally circulating fluidized bed (ICFB) was applied to investigate the behavior of chlorine and sulfur during cofiring RDF and coal. The pollutant emissions in the flue gas were measured by Fourier transform infrared (FTIR) spectrometry (Gasmet DX-3000). In the tests, the concentrations of the species CO, CO2, HCl, and SO2 were measured online. Results indicated when cofiring RDF and char, due to the higher content of chlorine in RDF, the formation of HCl significantly increases. The concentration of SO2 is relatively low because alkaline metal in the fuel ash can absorb SO2. The concentration of CO emission during firing pure RDF is relatively higher and fluctuates sharply. With the CaO addition, the sulfur absorption by calcium quickly increases, and the desulfuration ratio is bigger than the dechlorination ratio. The chemical equilibrium method is applied to predict the behavior of chlorine. Results show that gaseous HCl emission increases with increasing RDF fraction, and gaseous KCl and NaCl formation might occur.

Release of Sulfur and Chlorine During Cofiring Rdf and Coal In An Internally Circulating Fluidized Bed

An internally circulating fluidized bed (ICFB) was applied to investigate the behavior of chlorine and sulfur during cofiring RDF and coal. The pollutant emissions in the flue gas were measured by Fourier transform infrared (FTIR) spectrometry (Gasmet DX-3000). In the tests, the concentrations of the species CO, CO2, HCl, and SO2 were measured online. Results indicated when cofiring RDF and char, due to the higher content of chlorine in RDF, the formation of HCl significantly increases. The concentration Of SO2 is relatively low because alkaline metal in the fuel ash can absorb SO2. The concentration of CO emission during firing pure RDF is relatively higher and fluctuates sharply. With the CaO addition, the sulfur absorption by calcium quickly increases, and the desulfuration ratio is bigger than the dechlorination ratio. The chemical equilibrium method is applied to predict the behavior of chlorine. Results show that gaseous HCl emission increases with increasing RDF fraction, and gaseous KCl and NaCl formation might occur.

Effect of network modifiers on spectroscopic properties of erbium-doped phosphate glasses

The integrated absorption cross section Sigma(abs), I peak emission cross section sigma(cmi), Judd-Ofeld intensity parameters Omega(iota) ( t = 2,4,6), and spontaneous emission probability A(R) of Er3+ ions were determined for Erbium doped alkali and alkaline earth phosphate glasses. It is found the compositional dependence of sigma(emi) 5 almost similar to that of Sigma(abs), which is determined by the sum, of Omega(1) (3 Omega(2) + 10 Omega(4) + 21 Omega(6)). In addition, the compositional dependence of Omega(1) was studied in these glass systems. As a result, compared with. Omega(4) and Omega(6) the Omega(2) has a stronger compositional dependence on the ionic radius and content of modifers. The covalency of Er-O bonds in phosphate glass is weaker than that in silicate glass, germanate glass, aluminate glass, and tellurate glass, since Omega(6) of phosphate glass is relatively large. A(R) is affected by the covalency of the Er3+ ion sites and corresponds to the Omega(6) value.

不同玻璃组分对掺铒碲酸盐玻璃 光谱性质的影响

Series of tellurite glasses were prepared by traditional melting method, the glass composition were changed and the different effects of glass modifier oxides(alkali metals and alkaline earth metal oxides) and glass intermediate (Y2O3, GeO2, Nb2O5, WO3) on the optical and spectroscopic properties of Er³⁺ doped tellurite glass were researched and compared. The infrared transmitting spectra, absorption spectra and fluorescence spectra were tested, the results showed that Nb2O5 and WO3 in the glass act as part of the body's role in the formation of the network, caused the reduction of transmitting range in infrared wavelength, which decrease the transmitting properties of tellurite glass. The introduction of high valence cationic ions, WO3 especially, can increase the FWHM of Er³⁺ for the increased polarization effect. With the decreasing of cationic field of glass modifier ions, the ion filed of the environment around Er³⁺ increased, subsequently, the role of ligand field polarization effect reduced, which makes the luminescence lifetime increase, and on the contrary the FWHM decrease monotonously.

碱金属氟化物对掺Yb~(3+)氟磷酸盐玻璃析晶稳定性和光谱性质的影响

研究了碱金属氟化物对掺Yb3+氟磷玻璃的光谱性质和析晶稳定性能的影响。运用倒易法计算了Yb3+的发射截面。结果显示,LiF的引入对吸收和发射截面的提高作用较大并出现最佳引入量极值,其次为KF。碱金属氟化物的引入可提高二元体系的析晶稳定性能,使玻璃网络结构得到改善;拉曼光谱显示二元体系中引入YbF3后玻璃网络结构得到增强,而在引入碱金属氟化物的三元体系中掺杂YbF3后破坏了网络完整性,降低系统析晶稳定性能。

碱金属和碱土金属氟化物对掺Er^3＋氟磷酸盐玻璃光谱性质的影响

研究了碱金属和碱土金属离子修饰的掺Er^3＋氟磷酸盐玻璃的光谱性质，讨论了碱金属和碱土金属对铒氟磷玻璃的吸收和发射截面、荧光半高宽，Judd-Ofelt强度参数和上转换发光强度等光谱性质的影响，并与一些传统氧化物玻璃系统进行了比较．研究表明碱金属K^＋和碱土金属Sr^2＋掺杂高的玻璃更适宜用作光放大器基质．含12mol％K^＋的氟磷玻璃展现出7．83×10^-21cm^2的高发射截面和最小的荧光上转换强度；含23mol％Sr^2＋的氟磷玻璃则有7．58×10^-21cm^2的高发射截面、65nm的荧光半高

Electrochemical fabrication and electronic behavior of polypyrrole nano-fiber array devices

Electrochemically active Polypyrrole (PPy) nano-fiber array device was fabricated via electrochemical deposition method using aluminum anodic oxide (AAO) membrane as template. After alkaline treatment electrochemically active PPy nano-fiber lost electrochemical activity, and became electrochemically inactive PPy. The electronic properties of PPy nano-fiber array devices were measured by means of a simple method. It was found that for an indium-tin oxide/electrochemically inactive PPy nano-fiber device, the conductivity of nano-fiber increased with the increase of voltage applied on the two terminals of nano-fiber. The electrochemical inactive PPy nano-fiber might be used as a nano-fiber switching diode. Both Au/electrochemically active PPy and Au/electrochemically inactive PPy nano-fiber devices demonstrate rectifying behavior, and might have been used for further application as nano-rectifiers. (c) 2005 Elsevier B.V. All tights reserved.

松嫩平原碱化草地景观空间格局及环境因子的综合分析

本文对松嫩平原羊草地的群落结构及空间格局进行了分析，主要内容包含以下三个方面： 1、本文第一部分是对碱化草地植物群落分布的空间、环境因子分离。决定碱化草地植物物种在空间分布的因素可以大致分解成4个部分：（1）通过物种的生态位起作用的环境因子;（2）决定物种、群落间竞争激烈程度的空间距离因子;（3）环境和空间因子的交叉或耦合作用;（4）其它未知因子（如生物和随机因子）。本研究在1996年野外实地采样的基础上，运用DCA消势对应分析（Detrended Correspondence Analysis）对群落主要变化趋势及其与土壤环境因子之间的关系进行了分析。运用DCCA消势典范对应分析（Detrended Canonical Correspondence Analysis）对影响松嫩平原碱化草地群落结构季节动态的空间和环境因素进行了定量的分解。结果表明： 在影响群落分布的各因子中，环境因子独立约占40％，而环境一空间耦合因子占35％，空间因子独立约占3％，其它因子约占20％。在诸多因子中，土壤的盐渍化程度在整个生长季起着决定性作用，但土壤水分和氮素的作用因季节而变化。在干旱季节，植物生长的主要制约因子表现为土壤碱化度和土壤水份，而土壤氮素的作用处于次要地位。但在降雨较多、土壤湿润度较大的季节，土壤氮素的影响明显增强，成为仅次于土经度的决定性因素。 2、第二部分对东北松嫩平原碱化草地植物群落空间格局的分形性质进行了分析，分别用边长－面积指数和Korcak指数估计了斑块边界复杂性和斑块面积分布的分形维数。结果表明： 随放牧强度增加，占优势的羊草斑块的相对斑块化加剧，而斑块的边界在中度放牧时最不规则： 在水淹地，占优势的羊草斑块和次优势的碱茅斑块、獐茅斑块的斑块边界复杂性和斑块化程度比未水淹地都低，说明水降低了群落复合体内的异质性： 水淹地优势植物斑块的边长－面积指数和Korcak指数均低于次优势种，但在重度放牧地结果好相反，说明两种样地处于不同的演替阶段; 斑块边界复杂性符合同一尺度规律，在现有的面积范围以内没有尺度转换，而斑块面积分布则存在尺度转换点。对重牧地和水淹地的尺度分析表明，较小尺度上， 群落空间格局的相对斑块化程度较低，说明较小尺度上的空间格局要相对稳定一些，而较大尺度上则相反。可能原因是放牧干扰对大尺度的斑块影响更大。 3、对1989年开始围栏封育的样地10年来的空间格局变化进行时间序列分析，研究恢复演替过程中各个主要斑块类型的分布特征及动态，以及整个样地总体格局在演替系列中的变化。得出如下结果： 羊草是该区植被的优势种，其格局动态为：1989－1993年，羊草斑块总面积增加，斑块数目减少，相对斑块化指数降低，1994年后羊草的空间格局基本稳定。 羊草的斑块面积分布曲线在20平方米左右发生转折，即空间格局在此尺度发生尺度转换。不同尺度上斑块的相对斑块化指数及其在恢复演替中的变化趋势不同：小斑块的相对斑块化指数低，在1989－1993年期间增加，而后降低;大斑块的情况正好相反。说明羊草空间格局的主要变化之一是中等大小斑块的合并和数目减少，羊草斑块生长对格局的影响比斑块合并的影响要小。 獐茅斑块的格局动态为：1989－1994，斑块总面积、斑块数目、最大斑块面积增大，1995年开始降低。相对斑块化程度则先降后增。碱蓬斑块在1989－1993年间的格局动态与羊草正好相反：总面积减少，斑块数目增加，斑块面积大小的变化范围变窄，说明1993年之前，控制碱蓬斑块的主要生态学过程是其他物种的侵入，隔离原来较大的斑块，同时占据某些小斑块。1994年之后，碱蓬斑块的变化比较随机，其格局变化受到其他物种如杂草对策种虎尾草等的影响很大。 样地总体格局的变化为：1991年前，斑块种类和总斑块数目增加，斑块化程度随着增大;1993年后，斑块种类基本稳定下来;1991－1995，斑块化指数降低。在此期间，斑块数目增加，所以斑块化程度降低意味着斑块大小频率分布趋于均匀，大斑块被分裂，小斑块在长大，群落总体空间格局逐渐稳定。总体格局在三个尺度上有不同的自相似规律，这三个尺度分别为：La(a)<=1; 15.5。小尺度上相对斑块化程度低，但年际间变化较中尺度剧烈;中尺度相对斑块化程度变化较为缓，大尺度上，斑块分布一直趋于减少最大的斑块数目。总的变化趋势为，随恢复演替的深入，最大和最小的斑块数目都减少，处于中间尺度的斑块最多。

ISOLATION AND PROPERTIES OF A BLOOD-COAGULATION FACTOR-X ACTIVATOR FROM THE VENOM OF KING COBRA (OPHIOPHAGUS HANNAH)

A specific blood coagulation factor X activator was purified from the venom of Ophiophagus hannah by gel filtration and two steps of FPLC Mono-Q column ion-exchange chromatography. It showed a single protein band both in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and alkaline polyacrylamide gel electrophoresis. The mol. wt was estimated to be 62,000 in non-reducing conditions and 64,500 in reducing conditions by SDS-PAGE. The isoelectric point was found to be pH 5.6. The enzyme had weak amidolytic activities toward CBS 65-25, but it showed no activities on S-2266, S-2302, thrombin substrate S-2238, plasmin substrate S-2251 or factor Xa substrate S-2222. It had no arginine esterase activity toward substrate benzoylarginine ethylester (BAEE). The enzyme activated factor X in vitro and the effect was absolutely Ca2+ dependent, with a Hill coefficient of 6.83. It could not activate prothrombin nor had any effect on fibrinogen and thus appeared to act specifically on factor X. The procoagulant activity of the enzyme was almost completely inhibited by serine protease inhibitors like PMSF, TPCK and soybean trypsin inhibitor; partially inhibited by L-cysteine. Metal chelator EDTA did not inhibit its procoagulant activity. These results suggest that the factor X activator from O. hannah venom is a serine protease.