工业型城市不同道路两侧土壤重金属污染状况对比分析

在安徽省某市主干路、次干路和支路3种类型道路两侧22个采样点重金属含量测试的基础上,运用地累积指数法和潜在生态危害指数法对土壤中Mn、Pb、Co、Cr、As和Cd6种重金属进行污染分析和风险评价,并运用因子分析法和聚类分析法对重金属来源进行识别。结果表明:某市道路两侧土壤重金属元素平均含量从大到小依次为MnPbCoCrAsCd,次干路的Cr含量相对主干路和支路要低的多;地累积指数表明,城区主干路、次干路、支路两侧土壤均存在一定程度的重金属污染,Cr尚未污染或强污染,整体状况良好,Mn属于中等污染水平,Co、Pb属于强污染水平,Cd属于极严重污染水平;潜在生态危害指数法表明,Cd为严重生态风险程度,Pb、Co为较重生态风险程度,As为中等生态风险程度,Mn、Cr为低生态风险程度,从总体潜在生态危害指数来看,次干路的生态风险相对主干路、支路要低,均已达到严重潜在生态风险程度,后期土壤环境治理过程中应加强对Cd、Pb、Co的治理;因子分析从重金属元素中提取了2个主成分,可解释总变量86.277%,PC1(Cd、As、Cr)表示工业污染,PC2(Pb、Mn、Co)表示交通污染。     

磁聚焦电导率成像系统的阵列线圈驱动电路设计实现

利用晶体振荡器设计稳定度很高的信号源,其输出由可编程放大器调节后,经过功率放大电路输出至线圈阵列,实现了对三种不同结构和性能的阵列线圈的驱动, 使线圈阵列达到很好的磁场聚焦效果.     

Relationship between the atmospheric heat source over Tibetan Plateau and the heat source and general circulation over East Asia

On the basis of NCEP/NCAR version I daily reanalysis data from 1971 to 2000 and by the methods of inverse calculation, correlation analysis and comparative analysis, the influences of atmospheric heat source （AHS） over the Tibetan Plateau on the large-scale AHS and the general circulation in summer are studied in this paper. The results show that AHS over the plateau in summer may trigger a heat source wavetrain propagating northeastward along the coast from the East Asian continent and West Pacific to Bering Strait-Arctic or even North America. In addition, if AHS over the eastern plateau is intense, South Asian High moves to southeast and West Pacific subtropical high moves to southwest; on the contrary, if AHS over the eastern plateau is weak, South Asian High moves to northwest and West Pacific subtropical high moves to northeast. Therefore, South Asian High and West Pacific subtropical high move in the horizontally-opposite directions in terms of interannual variation, for which AHS over the eastern plateau seems to be thermodynamically responsible.     

Sea surface temperature and terrestrial biomarker records of the last 260 ka of core MD05-2904 from the northern South China Sea

This paper reports high-resolution biomarker records of the last 260 ka for core MD05-2904 from the northern South China Sea （SCS）. The sea surface temperature （SST） record using the U37^k＇, index reveals a minimum of 21.5℃（MIS 2） and a maximum of 28.3℃（MIS 5.5）, for a temperature difference of almost 7℃, and provides the longest high-resolution U37^k＇ SST record in northern SCS. The content of odd-number long chain n-alkanes and several n-alkanes indexes such as the CPI, ACL and the C31/C27 ratio, all reveal generally higher values during the glacials and lower values during the interglaclals. Terrestrial input as Indicated by n-alkane content was mostly controlled by sea-level changes： During the glacials, lower sea-level exposed the continental shelf to enable rivers to transport more terrestrial materials to the slope; and the situation reverses during the interglacials. The n-alkane indexes changes reveal more n-alkanes from contemporary vegetation during glacials as a result of the proximity of the core site to the source region, while the increases in ACL and C81/C27 ratio during glaclals indicate a change to more grassy vegetation. However, the highest values for CPI, ACL and the C81/C27 ratio all occurred during late MIS 3, and it was suggested that this period was characterized by a strong summer monsoon-dominated humid climate which resulted in a denser vegetation for the exposed continental shelf region.     

单片机控制HSW－1500高速带极堆焊电源的研制

在带极堆焊电源模拟控制研究的基础上，开展了新型微机控制系统的研究，介绍了这种电源控制系统的电路组成和工作原理。研究结果表明：数控高速堆焊电源ＨＳＷ－１５００，输出电压稳定、调节范围广、网压波动补偿能力强，保护性能可靠，达到了ＨＳＷ法和ＥＳＷ法对电源提出的性能要求，能够获得高质量的焊道。     

反应式步进电机控制电路设计

使用ＳＤＫ８６单板机的８２５５Ａ接口、驱动电源外接档和光电开关，对步进电机的控制。实现电机启、停、变换和换向等功能，同时也实现系统中电扫描和机械扫描的同步。     

从造纸术摇篮到造纸工业现代化

众所周知，我国是造纸术的摇篮。造纸术的外传曾经一度起到促进世界文化发展的作用。然而，我国却经历了数百年的历程，机制纸才开始取代手工造纸，事实上，我国造纸工业是在中华人民共和国成立后，才开始阔步前进，并在1993年其纸和纸板总产量跃居世界主要产纸国家第三位。然而，人均消费量依然仅有36公斤，远远落后于世界平均水平的50公斤。为了促进我国造纸工业的现代化和健康发展，今后务必着眼于可持续纤维原料的开发和利用，认真执行清洁生产和质量第一的技术路线。这就意味着有必要在纤维原料中增加木材的份额。与此同时，又必须妥善处理工厂排污（特别是蒸煮废渣的处理），务使取得更好的环境保护效果。不言而喻，也就更有必要加强科研与开发工作，针对我国纤维原料的特点有所创新，并做到在实际生产中得到兑现。     

用于化学实验温度测量的精密测温仪制作

本文主要详细阐述了精密测温仪的制作和使用。     

极光光谱学发展史和现状

本文阐述了极光光谱学的发展历史和现状,并进一步说明极光绿线的解释对极光光谱学发展的贡献,以及激发过程的深入研究会出现的新问题.