Application of modified Nafion membrane to the sulfur dioxide gas electrochemical sensor

The electrochemical SO2 sensor worked at the fixed potential and prepared with Nafion membrane as the solid electrolyte was studied. It v as observed that after Nafion membrane, was treated with H2SO4, the water-preserving ability of the membrane was increased. In turn, the performance of the sensor became stable. After lifetime test for 4 months, the performance of the sensor deceased slightly, Thus this kind of sensor may become a gas sensor for the practical application.

Cryopreservation of flounder (Paralichthys olivaceus) sperm with a practical methodology

A simple and convenient protocol for the cryopreservation of the flounder (Paralichthys olivaceus) sperm was established for "on the spot" cryopreservation of large quantities of semen. The use of three cryoprotectants, dimethyl sulphoxide (DMSO), glycerol (Gly) and methanol was tested in the method. The percentage of motile sperm present in semen after it had been frozen and thawed in the presence of DMSO, Gly or methanol was 60.5 +/- 3.6, 79.17 +/- 4.5 and 13.25 +/- 4.7%, respectively. The fertilization rates of this sperm were 67.06 +/- 15.1, 76.20 +/- 10.0 and 44.93 +/- 22.6%, while the hatching rates of eggs fertilized with this sperm were 37.40 +/- 8.3, 48.18 +/- 25.7 and 23.35 +/- 10.8%, respectively. It was found that Gly and DMSO were better cryoprotectants than methanol, with Gly giving the best overall results. Under scanning electron microscopy, it could be seen that while the majority of the frozen-thawed sperm remained morphologically normal, some exhibited lost or dilated mitochondria, swollen mid-pieces, broken tails, or damaged cell membrane, which probably caused the decrease in motility and fertility of the frozen-thawed sperm. (C) 2003 Elsevier Science Inc. All rights reserved.

准噶尔盆地侏罗系层序格架和油气成藏条件研究

Jurassic is an important hydrocarbon-bearing formation in Junggar Basin. Analyzing in strata sequence stratigraphy and hydrocarbon formation has both theoretical and practical values. First of all, strata sequence stratigraphy of continental facies is a new development and supplement in the theory of stratigraphic geology. Stratum of continental facies, unlike sea facies, has rich sup-plements, rapid facies changes, and was influenced slightly by sea level changes. The structural background and sedimentary environment of the basin in west China are greatly different from those of the basins in east China. So it is important to build the patterns of strata sequence stratigraphy in west China basins. Secondly, it is also of significance to find out all kinds of traps, for the dominant types are structural ones so far. After 50 years exploration, the stratigraphic or litholigic traps have become the main concern. This desertation is mainly focused on establishing the isochronal strtaum frame for Junggar Basin to show the evolvement characters of the basin sediment system and the regionalstuctrue background. By analyzing the conditions and patterns of the regional oil and gas bearing formations with typical cross-sections, we have established the patterns of sedimentary conditions for different reserviors. By authur's study, several fruitful results have been obtained in the following: Strata sequence frame and evolvement characteristics of Jurassic: By studing strata sequence, Jurassic has been divided into 2 second rank strata sequences and 3 third rank strata sequences based on the interface unconformities. Only 2 fourth rank strata sequences were grouped in BaDaoWan group. Also different seismic facies and sediment units have been recognized with the establishment of the of sediment system model. The oil-gas system characteristics in Jurassic: We conclude that hydrocar bon resources have the best oil potential. Potential of coal, carbonaceous and dark mudstone were reduced in turn. In this thesis we have made the evaluation of three hydrocarbon sources and the distribution oil-gas resource, and studied the potentials of hydrocarbon and evolvement for each kind of micro-component of the two main resource rocks. Prediction of paleo-temperature: In Junggar basin the evolvement of paleo-ground temperature can be divided into three stages. From Carboniferous to early Permian grads of ancient ground temperature was 8-5 ℃/100m, 5-3 ℃/100m from later period of Permian to end Trias, 3-2 ℃/100m from Jurassic to early Tertiary. Patterns of Jurassic hydrocarbon-bearing reserviors: There were two kinds of hydrocarbon source of Permian and Jurassic. They form different hydrocarbon - bearing systems. Six fundamental hydrocarbon - bearing trap modeS have been established. Directions for later exploration: There were two kinds of regional belts in Jurassic, One is structural belt caused by Yanshan and Ximalaya process, and the other was the stratum one caused by paleostructural rises.

企业效率表现和中国环境政策-以造纸企业为例

Understanding relationship between environmental protection and economic development is crucial to form practical environmental policy. At micro level, implementation of environmental regulations often causes production mills adjustment of technology which might leads to change of productive efficiency and cost, which, in turn, determine effort level of mills and even local government in pollution control. Using a stochastic frontier production model and a set of survey data on 126 paper mills from six provinces of China, we measure the technical efficiency changes and analyze the determinants of efficiency. in particular, we examine impact of environmental policy on paper mills' efficiency, using an indicator of environmental policy-the levy ratio of COD. We also estimate a simultaneous-equation model in which the levy rate and emission are jointly determined. The results indicate that there have been efficiency improvements during 1999-2003, when enforcement of environmental regulations have been tightened. The impacts, nevertheless, are different for different types of mills. We also find the levy ratio, which is influenced by both the local social and economic conditions and the characters of paper mills, such as scale, has strong impact on the abatement of the pollutant-COD. Additionally, paper mills' technical efficiency has positive effect on the reduction of the emission intensity of the pollutant-COD. These results lead a set of implications pertinent to policy improvement.

A practical approach to the degradation of polychlorinated biphenyls in transformer oil

A practical and efficient disposal method for hydrodechlormation of polychlorinated biphenyls (PCBs) in transformer oil is reported. Transformer oil containing PCBs was treated by nanometric sodium hydride (nano-NaH) and transition metal catalysts. High destruction and removal efficiency (89.8%) can be attained by nano-NaH alone under mild conditions. The process exhibits apparent characteristics of a first order reaction. The reductive ability of nano-NaH was enhanced by the addition of transition metal catalysts. In the presence of TiCl4, 99.9% PCBs was hydrodechlorinated. The complex reducing reagents, Ni(OAc)(2) + i-PrONa, show extra hydrodechlorinating activity for di-chlorinated biphenyls. (c) 2004 Elsevier Ltd. All rights reserved.