光纤数字环路载波系统的发展

ＯＤＬＣ是当今用户接入网的新型设备，它一方面可取代端局，解决通信线路紧张和远距离大容量放号问题，另一方面也可满足日益增多的增值业务的需求。本文ＯＤＬＣ技术的基本原理，结合目前国内外常见ＯＤＬＣ系统，总结和对比了其基本特点，优势，并指明ＯＤＬＣ的技术发展方向和中国应用的前景。     

SDS对溶菌酶溶液乳化作用的影响研究

本文研究了溶菌酶（Lysozyme）溶液中加入SDS8以后对正辛烷乳化作用的变化规律，结合FTIR的测定结果，从结构万面解释了蛋白质乳化作用变化的原因．     

连铸圆管坯的质量及其控制(上)

目前我国尚无连铸圆管坯的国家标准或行业标准,各企业只执行自行制订的技术条件。根据试验和理论分析,建议在连铸圆管坯技术条件中增加有关表层细晶区、柱状晶区和等轴晶区厚度比例及芯部状态等内容,并提出了相应的控制方法;鉴于连铸圆管坯质量的重要性,建议尽快制订国家标准。     

摊铺机熨平板热变形分析及抑制措施

为保障摊铺机摊铺路面的平整度达到施工要求,必须保证熨平板热变形较小。本文针对某一摊铺机的熨平板进行了一系列的热-固耦合分析,针对工作状况下熨平板的热变形过大,提出了一种能大幅提高熨平板刚度、抑制热变形的撑拉杆系统,从而提高熨平板摊铺路面的平整度。     

“物理分布、逻辑集中”架构下调度系统一体化分析中心总体设计

特高压电网的建设使得电网运行特性呈现复杂性增加、一体化特征增强等特点,对调度系统的分析决策提出了一体化分析要求,而传统的调度系统无法适应这种新的需求。基于"物理分布、逻辑统一"的全网集散式调度与控制技术的总体思路,提出了一体化分析中心的总体架构,并基于该架构进行了模型中心、在线分析服务和离线分析服务的详细设计。结合未来电网发展趋势对电网分析决策的需求,指出了未来调度系统分析决策软件的发展方向,为电网在线调度决策的研发提供了参考。     

物化/厌氧水解/生物强化脱色处理印染废水

介绍了某印染废水工程实例,针对该工程废水的特点,设计采用物化沉淀—厌氧水解—生物接触氧化—曝气生物滤池组合工艺进行处理。在好氧生化阶段接种强化脱色菌,强化生物脱色效果。运行结果表明,进水CODCr为1 500 mg/L、BOD5为350 mg/L、色度为1 000倍时,处理出水水质为CODCr≤80 mg/L、BOD5≤25 mg/L、色度≤40倍,优于《纺织染整工业水污染物排放标准》(GB 4287—1992)的一级排放标准要求。     

Nitrogen export by runoff from agricultural plots in two basins in China

Runoff and sediment yields from agricultural fields are major sources of nitrogen (N) entering lakes in China. Export of sediment and N can be impacted by soil and cropping management practices, but there is relatively little information on N leaving agricultural fields in lake basins in China. Sediment and surface runoff N from a series of field plots in two experimental lake basins were evaluated in situ under simulated rainfall conditions. Objectives of the study were to evaluate the effects of crop cover, slope, and fertilizer application on N in surface runoff and eroded soils. Sediment yields varied from 4.3 to 299.0 g m^-2, depending on management practice. Mean dissolved nitrogen (DN) and total nitrogen (TN) concentrations are 1.35 and 5.4 mg L^-1, respectively, in Lake Taihu basin, while mean DN and TN concentrations are 2.66 and 4.3 mg L^-1, respectively, in Lake Baiyangdian basin. For all experimental plots in two basins, weighted average concentrations of N for total-N, dissolved N and sediment N are 1.0-5.0 mg L^-1, much higher than 0.2 mg L^-1, indicating a problem in lake eutrophication due to high N concentration from agricultural surface runoff. The estimated mean annual export of total N was 6.0 and 14.7 kg ha^-1 yr^-1 for Baiyangdian and Taihu lake basins, respectively. The study showed that significantly more N (approximately ranging from 10 to 90 of total N) exported was associated with sediment, constituting a long-term source of potentially bioavailable N in lakes.     

Model analysis of dissolved inorganic phosphorus exports from the Yangtze river to the estuary

In this paper, we estimate the inputs of phosphorus (P) to the Yangtze River Basin and exports of dissolved inorganic phosphorus (DIP) from the river to the estuary for the period 1970–2003, by using the global NEWS-DIP model. Modeled DIP yields range from 2.5 kg P km⁻² yr⁻¹ in 1970 to 4.6 kg P km⁻² yr⁻¹ in 1985, and then dramatically increase to 14.1 kg P km⁻² yr⁻¹ in 2003. No significant difference between the modeled and measured values at the level of P = 0.05 is observed. The study also demonstrates variable source contributions of P to the modeled DIP during the period 1970–2003. Point sewage P input accounted for approximately 100% in the period 1970–1985 and substantially decreased to 24.8% in 2003. Chemical fertilizer contributed 25.4% of DIP yields in 1986 and increased continuously to 50.3% in 2003, while a stable trend in manure P contribution averaging 22.9% of DIP yields was shown in the same period. The study concludes that P inputs to the Yangtze River Basin and the river DIP export to the estuary have substantially increased during the study period consequence to human pressure.     

基于超声波与红外线技术的测距系统的研究与应用

通过超声红外技术测距时,受温度影响存在超声波速度波动的问题.提出了基于BP神经网络的温度补偿算法,通过建立温度与超声波速度之间的映射关系,达到补偿速度测量的目的.针对BP网络容易陷入局部最小值的问题,采用引入动量项的BP网络来优化连接权系数,在全局范围内更加快速准确地找到最优化的权值和阈值.通过建模和仿真可知,温度补偿...     

新安江模型在瓦塘江流域短期洪水预报中应用

为满足泵站科学调度运行的要求和对库区瓦塘江泵站防汛淹没损失的考核,贵港航运枢纽分公司以"集团公司水调自动化系统"数据库为基础数据来源,以新安江模型建立了瓦塘江流域短期洪水预报系统。通过对瓦塘江流域洪水预报进行实例检验,及对模拟结果的评价指标进行分析,研究结果表明该系统能取到较高精度,为瓦塘江泵站的48 h实时调度提供科学依据。