磁变仪定向的研究

讨论了固定铁磁影响环境和无铁磁影响环境中磁变仪的定向问题，并对《地磁台站观测规范》提出了修改建议     

洪水等级和灾情划分问题

洪水等级是描述一次洪水大小的指标，而洪水灾度是描述一次洪水造成损失大小的指标。这两个指标从理论和应用方面来说都具有许多优点，概念明确，简单易行。     

特大型煤和瓦斯突出的地质条件及其成因

特大型煤和瓦斯突出危害极大，具有独特的发生条件，应专门研究。在全国９９ 次特大型煤和瓦斯突出详细研究的基础上，总结了特大型突出的一般特征及发生的地质和采矿条件，并给出了南桐矿区的几个临界值。对特大型突出地质条件的成因进行了较深入的探讨，提出了防止特大型突出的几点建议     

Transformational leadership and organizational commitment: mediating role of psychological empowerment and moderating role of structural distance

Using a sample of 520 staff nurses employed by a large public hospital in Singapore, we examined whether psychological empowerment mediated the effects of transformational leadership on followers' organizational commitment. We also examined how structural distance (direct and indirect leadership) between leaders and followers moderated the relationship between transformational leadership and organizational commitment. Results from HLM analyses showed that psychological empowerment mediated the relationship between transformational leadership and organizational commitment. Similarly, structural distance between the leader and follower moderated the relationship between transformational leadership and organizational commitment. Implications for research and practice of our findings are discussed. Copyright © 2004 John Wiley & Sons, Ltd.     

多相催化湿式氧化法处理高浓度难降解有机废水的研究

在高压反应釜内，采用自制颗粒贵金属催化剂催化湿式氧化法处理高浓度饲料抗氧化剂合成废水，探讨了温度、压力、进水pH等反应条件对废水处理效果的影响。在温度为220℃、总压为8MPa条件下，COD，TOC，TN和色度的去除率分别达到77．0％，66．1％，70．2％，91％；处理后的废水pH很低，催化剂显示出较好的耐酸性；随进水pH的增加，COD的去除率逐渐降低，出水pH增加。     

Atrazine sorption-desorption hysteresis by sugarcane mulch residue

Sorption and desorption kinetics are essential components for modeling the movement and retention of applied agricultural chemicals in soils and the fraction of chemicals susceptible to runoff. In this study, we investigated the retention characteristics of sugarcane (Saccharum spp. hybrid) mulch residue for atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine) based on studies of sorption-desorption kinetics. A sorption kinetic batch method was used to quantify retention of the mulch residue for a wide range of atrazine concentrations and reaction times. Desorption was performed following 504 h of sorption using successive dilutions, followed by methanol extraction. Atrazine retention by the mulch residue was well described using a linear model where the partitioning coefficient (K(d)) increased with reaction time from 10.40 to 23.4 cm3 g(-1) after 2 and 504 h, respectively. Values for mulch residue K(d) were an order of magnitude higher than those found for Commerce silt loam (fine-silty, mixed, superactive, nonacid, thermic Fluvaquentic Endoaquepts) where the sugarcane crop was grown. A kinetic multireaction model was successful in describing sorption behavior with reaction time. The model was equally successful in describing observed hysteretic atrazine behavior during desorption for all input concentrations. The model was concentration independent where one set of model parameters, which was derived from all batch results, was valid for the entire atrazine concentration range. Average atrazine recovery following six successive desorption steps were 63.67 +/- 4.38% of the amount adsorbed. Moreover, a hysteresis coefficient based on the difference in the area between sorption and desorption isotherms was capable of quantifying hysteresis of desorption isotherms.     

Research and application of method of oxygen isotope of inorganic phosphate in Beijing agricultural soils

Phosphorus (P) in agricultural ecosystems is an essential and limited element for plants and microorganisms. However, environmental problems caused by P accumulation as well as by P loss have become more and more serious. Oxygen isotopes of phosphate can trace the sources, migration, and transformation of P in agricultural soils. In order to use the isotopes of phosphate oxygen, appropriate extraction and purification methods for inorganic phosphate from soils are necessary. Here, we combined two different methods to analyze the oxygen isotopic composition of inorganic phosphate (δ¹⁸O_P) from chemical fertilizers and different fractions (Milli-Q water, 0.5 mol L^?1 NaHCO₃ (pH = 8.5), 0.1 mol L^?1 NaOH and 1 mol L^?1 HCl) of agricultural soils from the Beijing area. The δ¹⁸O_P results of the water extracts and NaHCO₃ extracts in most samples were close to the calculated equilibrium value. These phenomena can be explained by rapid P cycling in soils and the influence of chemical fertilizers. The δ¹⁸O_P value of the water extracts and NaHCO₃ extracts in some soil samples below the equilibrium value may be caused by the hydrolysis of organic P fractions mediated by extracellular enzymes. The δ¹⁸O_P values of the NaOH extracts were above the calculated equilibrium value reflecting the balance state between microbial uptake of phosphate and the release of intracellular phosphate back to the soil. The HCl extracts with the lowest δ¹⁸O_P values and highest phosphate concentrations indicated that the HCl fraction was affected by microbial activity. Hence, these δ¹⁸O_p values likely reflected the oxygen isotopic values of the parent materials. The results suggested that phosphate oxygen isotope analyses could be an effective tool in order to trace phosphate sources, transformation processes, and its utilization by microorganisms in agricultural soils.     

Producing biodiesel from waste animal oil by modified ZnO

Biodiesel produced by transesterification of waste animal oil is a promising green fuel in the future. ZnO-Al₂O₃ and ZnO/Zn₂Al composition oxides were prepared by co-precipitation method and impregnation method, respectively. The above catalysts were characterized by X-ray diffraction (XRD), Brunauer--Emmett--Teller (BET) and CO₂ adsorption and temperature-programmed desorption (CO₂-TPD) and show that the high activity for the catalyst is attributed to its high alkalinity. The reaction parameters were optimized and the results show that the transesterification ratio of waste animal oil can reach 98.7% with 10% ZnO/Zn₂Al catalyst after 2 h. Moreover, 10%ZnO/Zn₂Al compound oxides can be active for the successive cycles. The glycerol as a predominant by-product after transesterification is of high purity with high use value.