用在线流动注射法研究膜基萃取过程中的铵离子传质规律

采用氨气敏电极结合流动注射分析法，对中空纤维膜器中氨化二(2,4,4-三甲基戊基)膦酸(HBTMPP)-庚烷体系萃 取镱、铒过程的铵离子进行在线分析．结果表明，当NaOH浓度为0.02mol/L，响应保留时间为90ｓ时，铵离子 标准曲线在20×10-5～1.0×10-1mol/L铵离子浓度范围内，具有良好的线性关系．样品溶液的用量由普通电极 法的30mL降至0.5mL；样品测定频率可达15次/h．当HBTMPP被氨化后，在高PH范围内，氢离子的传质仍优先 于铵离子，PH值下降很快；然后是H+、NH4+的混合交换 ，料液相形成缓冲体系，PH值基本不变．同级萃取反萃 中，也有基本相同的传质规律

Stability of Mo/Si multilayer structure used in Bragg-Fresnel optics

The thermal and chemical stabilities of Mo/Si multilayer structure used in Bragg-Fresnel optics were studied to get optimal technological parameters of pattern generation. Mo/Si multilayers were annealed at temperature ranging from 360 to 770 K, treated with acetone and 5 parts per thousand NaOH solution, and characterized by small-angle x-ray diffraction technique as well as x-ray photoelectron spectroscopy, and Olympus microscopy.

铁(Ⅱ,Ⅲ)-邻苯二酚紫-表面活性剂双峰双波长分光光度法测定铁

在pH＝12.6的KCl-NaOH缓冲介质中，研究了铁(Ⅱ,Ⅲ)与邻苯二酚紫及表面活性剂的反应．结果表明，该配合物的最大吸收波长为570nm，对试剂空白的最大负吸收波长为480nm，两波长处吸光度之差ΔA与铁量在0～8μｇ/25mL范围内成线性，ε为76×104L·mol－1·cm－1，方法用于水样中铁(Ⅱ,Ⅲ)的测定，结果令人满意.

阴极保护条件下环氧基界面粘附性研究

用阴极剥离方法研究了3种类型环氧涂层在60℃的3.5%NaCl溶液中的抗阴极开裂行为，用静态浸泡方法测定了3种涂层自由涂膜在30%NaOH溶液中的增重动力学曲线，采用单向拉伸方法测定了涂层与基体金属的粘附力，从涂层的抗碱性及涂层与基体金属粘结性能分析了影响涂层阴极开裂的主要因素．结果表明阴极反应生成的碱性环境造成聚合物降解是导致涂层阴极开裂的主要因素，此外涂层与基体金属的粘附性能对涂层的开裂也有一定影响

Catalysis of copper-containing transition metal hydrotalcite-like compounds in the phenol hydroxylation with hydrogen peroxide

Hydrotalcite-like compounds containing carbonate ion as the interlayer anion were prepared by coprecipitation under low supersaturation condition by mixing an aqueous solution of metal nitrates with an aqueous solutions of NaOH and Na2CO3, at room temperature, maintaining pH = 8-10 with vigorous stirring, Following the mixing, the resulting heavy slurry was aged at 353 K for 18 h with vigorous stirring, The precipitate was then filtered, washed several times with hot distilled water and dried in air at 353 K overnight, In this way, CuMI AlCO3-HTLcs and M-I AlCO3-HTLcs were synthesized and characterized by means of XRD and IR, The catalysis of the above mentioned HTLcs were investigated in the phenol hydroxylation with H2O2. The results indicated that all of the copper-containing HTLcs had a higher catalytic activity in the reaction, However, those catalysts that did not contain copper had no catalytic activity in this reaction, This means that copper was the active center in the phenol hydroxylation. Meanwhile, the mechanism was also proposed, which could be used to explain the main reason for higher activity for CuCuAlCO3-HTLcs in the phenol hydroxylation and the effect of Mg2+, Zn2+, Co2+, Ni2+ on activity of CuMI AlCO3-HTLcs.

Detection of menadione sodium bisulfite (vitamin K-3) by reversed-phase high performance liquid chromatography with series dual-electrode amperometric detector

A reversed-phase high-performance liquid chromatography with series dual glassy carbon electrodes for the amperometric detection of water-soluble menadione is described. The complex post-column derivatization reaction and the high background currents were avoided. The menadione sodium bisulfite was reduced at -0.3 V vs. SCE at the upstream (generator) electrode and oxidized at +0.2V vs. SCE at the downstream (collector) electrode. The mobile phase was 0.2moll(-1) HAc-NaAc aqueous buffer (pH 5.50) and 40% (v/v) methanol. The linear response was in the range of 35 ng to 15 mu g, with a detection Limit of 15 ng (S/N=3). The correlation coefficient was 0.9997 (n=6). The electrochemical detection with series dual electrodes has a higher selectivity for menadione (vitamin K-3) compound than with UV detection.

Studies of Oxygen Reduction on Polycobaltprotoporphyrin Film with RRDE

The mechanism of oxygen reduction on polycobaltprotoporphyrin IX dimethyl ester (PolyCoPP) film has been studied by using the rotating ring(Au)-disk(pyrolytic graphite, PG) electrode (RRDE) technique. The PolyCoPP/PG electrode promotes the oxygen reduction via two-electron process which produces peroxide as a main product in O-2-saturated 0.1 mol.dm(-3) NaOH. Once HO2- has been formed, no further reduction to OH- takes place at the disk. When the disk potential shifts to more negative, either the direct reduction of O-2 to OH- or the further reduction of HO2- to OH- occurs.

KINETIC-STUDY OF ELECTROCATALYTIC REDUCTION OF HYDROGEN-PEROXIDE AT IRON(III) PORPHYRIN MODIFIED GLASSY-CARBON ELECTRODE IN ALKALINE-MEDIUM USING THE ROTATION-SCAN METHOD

Reduction of hydrogen peroxide at a glassy carbon (GC) electrode modified with sigma-bonded pyrrole iron(III) octaethylporphyrin complex, (OEP)Fe(Pyr), was studied by cyclic voltammetry and a rotating disk electrode. In 0.1N NaOH solution, it is shown that such an (OEP)Fe(Pyr)/GC electrode has a significant catalytic activity towards hydrogen peroxide reduction (E(D) = -0.80 V, k = 0.066 cm s(-1)); however, the electrode stability is low. The deactivation is observed when the reaction charge (Q) is passing through the (OEP)Fe(Pyr)/GC disk electrode. A linear rotation scan method is applied to study the kinetic process by determining the disk electrochemical response (i(D)) to rotation rate (omega) at a definite disk potential (E(D)). Considering that the number of adsorbed electroreduced catalyst molecules (Red) varies according to the disk potential, a factor theta(= Gamma(Red)/(Gamma(Red) + Gamma(Ox))) is introduced to describe the electrode surface area fraction for electroreduced species. The obtained Koutecky-Levich equation is applicable whatever the potential is.

FABRICATION OF STM TIPS WITH CONTROLLED GEOMETRY BY ELECTROCHEMICAL ETCHING AND ECSTM TIPS COATED WITH PARAFFIN

We have presented two simple methods of ''unfixed-position shield'' and ''pulling out'' for making sharp STM Pt-Ir tips with low aspect ratio by electrochemical etching in KCN/NaOH aqueous solution and ECSTM tips coated with paraffin. By limiting the elec

磷酸三丁酯萃淋树脂富集水中痕量酚类化合物的研究

本文以磷酸三丁酯(TBP)萃淋树脂为柱填料,研究了富集水中酚类化合物及其洗脱条件。结果表明,以TBP萃淋树脂为富集剂,水样pH值为1～7,以30ml/min的流速通过吸附柱,用8ml 0.1mol/L的NaOH洗脱,多种酚类化合物回收率在97％～103％。此外还试验了地面水中常见干扰物的影响。该方法富集倍数达125倍,最低检测限0.5μg/L。对实际样品1～100μg/L范围内的测定相对标准偏差4.4％～8.8％。

PREFERENTIAL SORPTION OF MODIFIED PVA MEMBRANE IN PERVAPORATION

The swelling processes of an annealed poly (vinyl alcohol) membrane, a NaOH-crosslinked poly (vinyl alcohol) membrane, a poly (vinyl alcohol)-N,N'-methylene bisacrylamide irradiation-crosslinked membrane and a poly (vinyl alcohol)/poly(AMcoAANa) blend membrane were investigated. Water was preferentially sorbed by all four membranes. The selective sorption factor alpha(s) and the selective diffusion factor alpha(d) were defined, and were used to characterize the effects of sorption and diffusion on selectivity. The results have shown that preferential sorption has a marked effect on selectivity. The mean diffusion coefficients and pervaporation properties of the four membranes are also discussed.

AMPEROMETRIC DETECTION OF CATECHOLAMINES WITH LIQUID-CHROMATOGRAPHY AT A NOVELLY CONSTRUCTED PRUSSIAN BLUE CHEMICALLY MODIFIED ELECTRODE

A novel Prussian blue chemically modified electrode (CME) was constructed and characterized for liquid chromatography electrochemical detection (LCEC) of catecholamines. Both anodic and cathodic peaks could be obtained by monitoring at constant applied potential at anodic and slightly cathodic potential ranges (0.3-0.7 and -0.2-0.1 V vs. SCE), respectively. When arranged in a series configuration, using the modified electrodes as generating and collecting detectors, extremely high effective collection efficiencies of 0.91 (for norepinephrine) and 0.58 (for dihydroxyphenylacetic acid) were achieved in dual-electrode LCEC for catecholamines; and a linear response range over 3 orders of magnitude and a detection limit of 10 pg were obtained with a downstream CME as the indicating detector.

DSC法对溶剂在膜中状态的研究

本文用DSC对溶剂在PVA热交联膜、PVA/NaOH膜PVA/MBA膜及PVA/P(AmCoAANa)共混膜中状态进行研究,在溶胀状态下,水存在三种状态即自由水中间水及键合水,水/乙醇溶液则存在自由态及其它状态,在渗透气化状态下,对于PVA/P(AmCoAANa)共混膜,当料液为水时,则有自由态水存在。另外结合测定渗透气化状态下膜中溶剂含量初步探讨了渗透气化机理。

Physical modeling of localized scour for the Yangtze Estuary Waterway Improvement Project, Phase I

In order to examine the effectiveness of engineering protection against localized scour in front of the south groin-group of the Yangtze Estuary Waterway Improvement Project, Phase I, an undistorted physical model on a geometric scale of 1:250 is built in this study, covering two groins and their adacent estuarine areas. By use of rinsing fix-bed model as well as localized mobile-bed model the experiment is undertaken under bi-directional steady flow. According to the experimental results, waterway dredging leads to the increase in steram velocity, the increase being larger during the ebb than during the flood. Construction of the upstream groin has some influence on the flow patterns near the downstream groin. Localized scour in front of the groin-heads is controlled mainly by ebb flow. In the case of a riverbed composed entirely of silt, the depths of localized scour in front of the two groin-heads are 27 m and 29 m, respectively. In reality, the underneath sediment of the prototype riverbed is clay whose threshold velocity is much higher than the stream velocity in the Yangtze Estuary; therefore, the depths of localized scour will not be much larger than the thickness of the silt layer, i. e. 7.4 m and 4.7 m, respectively. The designed aprons covering the riverbed in fron of the groin-heads are very effective in scour control. Aprons of slightly smaller size can also fulfill the task of protection, but the area of localized scour increases significantly.

Involvement of p90 ribosomal S6 kinase in termination of cell cycle arrest during development of Artemia-encysted embryos

Artemia has evolved a unique developmental pattern of encysted embryos to cope with various environmental threats. Cell divisions totally cease during the preemergence developmental stage from gastrula to prenauplius. The molecular mechanism of this, however, remains unknown. Our study focuses on the involvement of p90 ribosomal S6 kinase (RSK), a family of serine/threonine kinase-mediating signal transduction downstream of mitogen-activated protein kinase cascades, in the termination of cell cycle arrest during the post-embryonic development of Artemia-encysted gastrula. With immunochemistry, morphology, and cell cycle analysis, the identified Artemia RSK was established to be specifically activated during the post-embryonic and early larval developmental stages when arrested cells of encysted embryos resumed mitoses. In vivo knockdown of RSK activity by RNA interference, kinase inhibition, and antibody neutralization consistently induced defective larvae with distinct gaps between the exoskeleton and internal tissues. In these abnormal individuals, mitoses were detected to be largely inhibited in the affected regions. These results display the requirement of RSK activity during Artemia development and suggest its role in termination of cell cycle (G(2)/M phase) arrest and promotion of mitogenesis. Our findings may, thus, provide insights into the regulation of cell division during Artemia post-embryonic development and reveal further aspects of RSK functions.