进口硫磺对我国磷复肥工业发展战略的影响

根据近几年我国进口硫磺量的迅速增长,2005年进口量达830万t,占全球硫磺产量的1/5,导致国际硫磺价格猛涨,1997年硫磺到岸价在35~45美元/t,2005年已达94.4美元/t以上,分析国际硫磺价格猛涨对我国磷复肥发展的巨大影响,而我国2006~2007年还将增加硫磺制酸能力540万t。为此,提出几点应对策略,新建硫酸装置应采取一炉两用的原料路线,并提出必须大力挖掘国内硫资源。     

刑事案件现场中微量玻璃的检验及应用

论述了刑事案件现场上微量玻璃检材的组成、提取与包装、检验方法以及在侦破刑事案件中的应用.     

Patterns in the crustacean zooplankton community in Lake Winnipeg,Manitoba: Response to long-term environmental change

Changes in the crustacean zooplankton community composition and abundance in Lake Winnipeg (1969–2006) provide a rare opportunity to examine their response to environmental changes in the largest naturally eutrophic lake on the Canadian prairies. Since 1929, zooplankton species composition in Lake Winnipeg has changed little except for the addition of the invasive cladoceran, Eubosmina coregoni in 1994. The dominant taxa in the lake in summer include: Leptodiaptomus ashlandi, Acanthocyclops vernalis, Diacyclops thomasi, Daphnia retrocurva, Daphnia mendotae, Diaphanosoma birgei, Eubosmina coregoni, and Bosmina longirostris. Climate-accelerated nutrient loading to southern Lake Winnipeg over the last two decades has led to increased phytoplankton abundance and higher frequency of cyanobacterial blooms especially in its northern basin. Crustacean zooplankton have likewise increased especially in the North Basin, but less so in the more nutrient rich South Basin, possibly as a consequence of higher densities of pelagic planktivorous fish and light-limited primary production compared with the more transparent North basin (Brunskill et al., 1979, 1980). Calanoid copepods play a larger role in the South basin food web in contrast to cyclopoid copepods and Cladocera in the North basin. The study begins to fill the recognized gap in understanding of Lake Winnipeg's food web structure and provides a baseline for evaluating ongoing changes in the zooplankton community with the arrival of new non-indigenous taxa, e.g. Bythotrephes longimanus and Dreissena polymorpha. It reinforces previous work demonstrating that zooplankton provide valuable indices toward evaluating the health of an ecosystem.     

负载硫化镉的碳纳米管载镉量分析

经高温灰化法预处理后用配位滴定分析法测定负载硫化镉的碳纳米管(CdS/CNTS)的载镉量,测试数据可靠准确,表明制备负载硫化镉碳纳米管催化剂时所加入的镉并不全部吸附在碳纳米管上,载镉效率随着碳纳米管载镉量的增加而降低。     

常温电沉积Fe—P—Al2O3复合镀层新工艺的研究

研究确定了常温下获得Fe-P-Al_2O_3复合电镀层的新工艺,获得的镀层光亮、致密、无裂纹,Al_2O_3颗粒的含量为5％～35％(vol),镀层显微硬度Hv=800～1100N/mm~2,耐磨性能比低温镀铁层提高5～10倍。     

2-甲基-1,3-丙二醇水溶液的表面性质研究

采用最大泡压法测定了常压下纯液体2-甲基-1,3-丙二醇(MPO)及不同浓度MPO水溶液在298.15~367.7 K范围的界面张力。实验结果表明,纯MPO及其水溶液的界面张力σ随温度升高而呈线性减小;恒温下σ随浓度的增加呈幂函数递减。MPO水溶液的表面层发生正吸附,与理论上低脂肪醇类表面张力的性质符合。而且低浓度下MPO水溶液的吸附等温线呈直线,与G ibbs吸附等温式描述的规律相吻合。     

Decentralized control: Status and outlook

This paper reviews state of the art in the area of decentralized networked control systems with an emphasis on event-triggered approach. The models or agents with the dynamics of linear continuous-time time-invariant state-space systems are considered. They serve for the framework for network phenomena within two basic structures. The I/O-oriented systems as well as the interaction-oriented systems with disjoint subsystems are distinguished. The focus is laid on the presentation of recent decentralized control design and co-design methods which offer effective tools to overcome specific difficulties caused mainly by network imperfections. Such side-effects include communication constraints, variable sampling, time-varying transmission delays, packet dropouts, and quantizations. Decentralized time-triggered methods are briefly discussed. The review is deals mainly with decentralized event-triggered methods. Particularly, the stabilizing controller–observer event-based controller design as well as the decentralized state controller co-design are presented within the I/O-oriented structures of large scale complex systems. The sampling instants depend in this case only on a local information offered by the local feedback loops. Minimum sampling time conditions are discussed. Special attention is focused on interaction-oriented system architecture. Model-based approach combined with event-based state feedback controller design is presented, where the event thresholds are fully decentralized. Finally, several selected open decentralized control problems are briefly offered as recent research challenges.     

A comprehensive approach to evaluating watershed models for predicting river flow regimes critical to downstream ecosystem services

Selection of strategies that help reduce riverine inputs requires numerical models that accurately quantify hydrologic processes. While numerous models exist, information on how to evaluate and select the most robust models is limited. Toward this end, we developed a comprehensive approach that helps evaluate watershed models in their ability to simulate flow regimes critical to downstream ecosystem services. We demonstrated the method using the Soil and Water Assessment Tool (SWAT), the Hydrological Simulation Program–FORTRAN (HSPF) model, and Distributed Large Basin Runoff Model (DLBRM) applied to the Maumee River Basin (USA). The approach helped in identifying that each model simulated flows within acceptable ranges. However, each was limited in its ability to simulate flows triggered by extreme weather events, owing to algorithms not being optimized for such events and mismatched physiographic watershed conditions. Ultimately, we found HSPF to best predict river flow, whereas SWAT offered the most flexibility for evaluating agricultural management practices.     

改进的HyperSplit报文分类算法

针对现有高速、大容量、多域报文分类算法普遍存在内存使用量大的问题,提出一种改进的HyperSplit多域报文分类算法。通过分析现有算法内存使用量大的原因,修正和设计选择分割维度与分割点、去除冗余结构的启发式算法,最大限度减少决策树中的复制规则数量,消除决策树中存在的冗余规则和冗余节点,优化决策树结构。仿真结果表明,该算法与现有多域报文分类算法相比,不依赖于规则集类型和特征,在保证内存访问次数不增加、报文得到线速处理的情况下,可降低算法的内存使用量,当规则集容量为105时,内存使用量降低到HyperSplit算法的80%。     

合成气中氨含量测定方法的改进

用快速测定仪测定气体中的氨含量，采气量为50ml，可准确测出高含量氨体积百分比含量为80%-100%和低含量氨体积百分比含量为1%-20%的样气，该仪器结构简单，易于制造，测定过程简单，结果准确，一目了然。