Release of polychlorinated biphenyls (PCB) in a salt-wedge estuary as induced by dredging or contaminated sediments.

An evaluation of the input of polychlorinated biphenyls (PCB) in the Duwamish River, Seattle, Wash., resulting from the dredging of contaminated sediments is presented. The mean concentrations of PCB during the monitoring period were 12.8 to 24.5 ng/liter in water and 1.03 to 1.77 microgram/g dry weight in suspended particulate matter. These values were within the ranges normally observed in the river, suggesting that the dredging operations did not induce a significant PCB pulse of potential hazard to the estuary. The fractionation of PCB in suspended particulate matter was determined by computing component concentration ratios, KN(d). These quantities indicate an enrichment factor of 10(5) from ambient water. Based on the ambient PCB load and normal discharge, the input of PCB into Puget Sound via the Duwamish River was estimated to be 36 kg/year.     

工程机械润滑剂的正确选用

本文概述了工程机械润滑的重要性,分析了工程机械润滑的特点,着重介绍了工程机械润滑剂的正确选用,并对进口工程机械的润滑剂如何选用、代用国产油品问题作了说明。     

一种对复杂对象的多粒度封锁技术

本文阐述了一种对复杂对象的多粒度封锁方法，给出了该方法采用的封锁协议和封锁相容矩阵，解决了传统的多粒度封锁在粒度，共享对象，权限方面存在的问题。     

Performance evaluation of an automation system — determination of a benchmzrk process

An average “real” process is determined from 55 processes automated by an automation system. This a first step in developing realistic benchmark processes for making objective evaluation tests between the performance of different automation systems. The most important properties of the average process that are independent of the automation system used and that are important performance indicators are presented in the paper.The real process, representing the statistical mean of the process data best, is a papermachine with a pulp making department. The process has 141 analog inputs, 50 binary inputs, 90 analog outputs, 63 binary outputs, 77 motor controls, 8 motor value controls, 308 process interfaces, and 165 displays.     

机械破壳机结构、工作原理及应用

脱壳率和碎仁率是带壳物料破壳的2个关键指标,机械破壳则是提高上述关键指标的重要途径之一。文章分析了常见的带壳物料机械破壳方式、机械破壳类型、机械破壳原理及发展现状,总结了机械破壳设备的优缺点,并对目前机械破壳应用过程中所存在的问题提出了建议。     

纸箱防潮技术及其应用

从纸板表面处理和浆料处理两方面介绍了纸板获得防潮性能的方法,以及不同处理方法和常用的防潮涂料的组成及特点.重点介绍了拨水剂、防潮上光剂及纤维素酶处理纸浆等近几年来国内外的研究成果和方法,分析和比较了多种表面用防潮剂、浆内用助剂的优缺点.     

林纸一体化视角的我国纸产品出口贸易国际竞争力研究

从出口贸易总量、产品结构和出口地区分布3个方面对我同纸产品出口贸易现状进行了分析,通过测算2003-2008年的贸易竞争力(TC)指数和显性比较优势(RCA)指数,对我国纸产品的国际竞争力进行了评估和实证分析.在分析制约我围纸产品出口主要问题的基础上,从林纸一体化视角提出了提升我国造纸业国际竞争力的对策与思路.     

高光泽彩喷纸图像打印质量的优势因素分析

采用灰关联分析方法对影响高光泽彩色喷墨打印纸图像打印质量的因素进行了优势因素分析.结果表明,纸张的粗糙度对高光泽彩喷纸打印图像的色密度、色域、色差和清晰度等均有非常明显的影响.而光泽度对纸张打印性能的影响并不显著.     

内燃机用阻燃型空气过滤纸的研制

实验探讨了以十溴二苯乙烷为主体的溴-锑协同阻燃体系中溴-锑元素质量比对空气过滤纸阻燃效果的影响,结果表明,二者最适质量比为3∶1。在此比例下,进一步研究了阻燃剂用量对空气过滤纸阻燃性能、力学性能以及透气性的影响,结果显示,阻燃剂留着率为25%时,阻燃性能达到GB/T14656—1993要求,此时挺度提高了约20%,但耐破度和透气度分别下降了约11%和10%。