骆马湖水环境变化趋势及对策研究

随着经济发展、城市化率的提高，加之滨湖开发，骆马湖的水质呈现一定的恶化趋势，生态系统遭受破坏，水体富营养化发展有越来越严重的趋势。通过对骆马湖营养化程度和污染原因的分析，提出了一些对策措施和解决办法，以期实现湖泊的生态、环境与经济的协调发展。     

新型涂料增稠剂的化学成分鉴定

本文用红外光谱法对一种新型涂料增稠剂进行了化学成分鉴定,其主要成分为羟丙基甲基纤维素与蒙脱土。     

A segmentation-based fine-grained peer sharing technique for delivering large media files in content distribution networks

Delivering large media files over the Internet is a challenging task because it has some unique features that are different from delivering conventional Web documents. In this paper, we propose a fine-grained peer sharing technique for dealing with the problem in the context of content distribution networks. The key difference of the technique from conventional peer-to-peer systems is that the unit of peer sharing is not a complete media file, but at a finer granularity. By doing so, we improve the flexibility of replica servers for handling client requests. We analyze the storage requirement at replica servers and design a scheduling algorithm to coordinate the delivery process from multiple replica servers to a client. Our simulations show that the fine-grained peer sharing approach can reduce the initial latency of clients and the rejection rate of the system significantly over a simple peer sharing method.     

Formation of mushroom-like ZnO microcrystals through a solution calcination process

Mushroom-like ZnO microcrystals have been prepared via a solution calcination route, using Zn(NO₃)₂ as Zn source in the absence of any surfactants, templates or catalysts. This is the first example to prepare mushroom-like crystals as semiconductors, which are expected to show particular physical properties. The ZnO products were investigated by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy and photoluminescence (PL) spectrum measurements. A suitable concentration of Zn(NO₃)₂ solution was important for the growth of the mushroom-like products. The reported synthetic procedure is straightforward and inexpensive, and thus can be readily adopted to produce large quantities of mushroom-like ZnO microcrystals.     

Deposition and Properties of Superconducting MgB2 Thin Films

The recently discovered superconductor MgB₂ with T _c at 39 K has great potential in superconducting electronics. In this paper, we review the deposition techniques used for MgB₂ thin films in the light of a thermodynamic study of the Mg-B system with the calculation of phase diagrams (CALPHAD) modeling technique. This thermodynamic study identifies a growth window in the pressure–temperature phase diagram, in which the magnesium pressure is very high for likely in situ growth temperatures. A Hybrid Physical–Chemical Vapor Deposition (HPCVD) technique that successfully achieves such a high Mg pressure is shown to produce in situ epitaxial MgB₂ thin films with bulk superconducting properties.     

杭-宁输气管道工程定向钻穿越设计浅析

杭州-宁波天然气输气管道工程（简称杭-宁输气管道工程）是浙江省天然气长输管网主干线之一，根据工程河流穿越众多、渠塘穿越频繁的特点，对杭-宁输气管道工程水域穿越的特点和穿越方式作了总结；重点分析了水域定向钻穿越设计及需要注意的问题，为今后浙江省天然气管网建设的水域穿越设计作了探讨。     

无线光接入技术

无线光通信系统以其高带宽、低成本和安装迅捷等优势成为非常有竞争力的光接入新技术。对无线光通信系统的关键技术、主要优势和存在的问题及国内外相关产品的发展状况和主要特点进行了论述和介绍。     

基于本地缓存的弹性分组环保护机制

本文提出一种基于本地缓存的弹性分组环保护倒换机制(WrapProtectionBasedOnLocalBuffers,简称WP-LB)。其主要思想是当环路上任何位于源节点和故障区域之间的中间节点接收到含有故障信息的控制信令后,就不再向下游转发数据分组,而是在本地缓存这些数据。等到保护通路建立好之后,再把缓存的数据分组经过保护通路发送给目的节点。分析计算表明,与原有的保护倒换(WrapProtection,简称WP)机制相比,WP-LB机制不仅提高带宽利用率,减少平均时延,并且还能避免数据包的丢失和失序。     

雷达仿真系统中电磁干扰环境的仿真设计和实施

雷达仿真系统是为检测雷达设备的抗干扰能力以及在各种电磁环境下的工作性能而设计的，包括有源干扰和无源干扰的模拟仿真。本文阐述了无源干扰即杂波的散射模型和仿真过程；从同步脉冲干扰的基本原理出发，阐明在雷达工作环境仿真系统中距离拖引、速度拖引、虚假目标等同步脉冲有源干扰的设计和实施过程；并针对工作在搜索和跟踪交替模式下的相控阵雷达提出自适应综合干扰方式；最后分析并总结了系统仿真时为真实、有效地模拟电磁干扰环境应注意的关键问题。