铸铝合金不同厚度膜层微弧氧化防腐蚀性能试验研究

针对某型铸铝合金的不同热处理状态、不同厚度的微弧氧化膜的防腐蚀性能进行了960 h的盐雾对比试验。结果表明,对于该型铸铝合金T7热处理状态防腐蚀能力优于T5;微弧氧化处理能明显提高该型铸铝合金防腐蚀能力,经不同厚度微弧氧化处理的该型铸铝合金,腐蚀深度无显著差异;在相同面积区域内,腐蚀损伤的程度有明显的不同,50～70μm的微弧氧化膜防腐蚀性能最好。     

乌东德库区消落带土壤水分分布特征

消落带土壤水分是制约植物生长发育的关键因素,对库区消落带生态修复意义重大.本文系统分析了乌东德库区消落带修复试验区土壤含水量分布,探索了土壤水分空间变化和影响因素.结果表明:研究区5月水分含量低于5％,不同试验分区和高程区域土壤水分分布受到微地形、土壤特征、植被类型和植被覆盖度等影响.土壤水分随深度变化的主控因素包括地...     

不同四环素浓度对好氧堆肥和蚯蚓堆肥过程影响的对比研究

好氧堆肥及蚯蚓堆肥是对畜禽粪便进行肥料化处置的有效方式,但畜禽粪便中残留的不同浓度四环素对二者堆肥过程的影响是否相同却并不清楚.因此,将不同浓度(5、25、125 mg·kg^-1)的四环素添加到牛粪-秸秆物料中,对比了好氧堆肥与蚯蚓堆肥堆制过程中堆体腐熟度指标的变化、堆肥产品养分含量的区别以及堆肥产品中四环素去除效率的差异,以期为不同浓度四环素的畜禽粪便肥料化提供适宜的处置方法 .研究结果显示,高浓度(125 mg·kg^-1)四环素添加延缓了好氧堆肥的升温进程,但与低浓度(5、25 mg·kg^-1)四环素添加处理相比并未显著影响堆体的腐熟度指标、堆肥产品总养分含量及速效养分含量.高浓度(125 mg·kg^-1)四环素添加导致了蚯蚓堆肥中蚯蚓密度和生物量的显著下降,并导致蚯蚓堆肥无法正常启动.在蚯蚓堆肥中,低浓度(5、25 mg·kg^-1)四环素添加处理之间在堆体的腐熟度指标,堆肥产品总养分含量及速效养分含量方面无显著差异.好氧堆肥对畜禽粪便中四环素的去除率可达90%以上,显著高...     

交联壳聚糖季铵盐与聚合铝复合的絮凝效果研究

研究了交联壳聚糖季铵盐与聚合铝复合后的絮凝特征。实验结果表明,壳聚糖季铵盐的絮凝效果与取代度有关,取代度在85%时絮凝效果较好。季铵盐交联后絮凝效果提高,用交联壳聚糖季铵盐与聚合铝复合,壳聚糖季铵盐与聚合铝的配比影响絮凝效果,当复合絮凝剂中壳聚糖季铵盐所占比例在20%附近时,絮凝效果最好。复合絮凝剂具有好的除浊效果,投药量低,pH值适用范围广,在达到良好的除浊效果的同时还降低了残留铝的浓度。用复合絮凝剂对造纸废水进行处理,浊度去除率可达95%,COD去除率达38%。     

外绝缘用液体硅橡胶老化现象的微观表征

本文针对近年来出现在一些变电站SF6电压、电流互感器的液体硅橡胶绝缘护套出现龟裂老化这一现象,对发生老化的硅橡胶材料进行了性能测试和试验,并利用红外光谱分析、XPS分析、热失重等手段分析了其微观结构和物质组成的变化。研究发现老化后的液体硅橡胶中Si-C、Si-O官能团和Si、C、O元素的相对含量发生了变化,且随着老化程度的增加呈现出较为明显的规律,老化越严重,Si-C键含量越少,C元素的含量越少,O元素含量越多。本文认为,用官能团含量、元素相对含量可以准确地表征液体硅橡胶材料的老化程度。通过对不同老化程度的液体硅橡胶进行的憎水性、耐漏电起痕性能的试验也证实了本文的观点。     

Changes in soil organic matter composition after afforestation of arable farmland in northeast China

Since the 1970s, a substantial area of arable farmland in a semi-humid area of northeast China has been planted as deciduous forests (Populus tomentosa Carr.). This study investigates the effects of afforestation on soil organic carbon (SOC) content and the chemical composition of the soil. Soil samples (Calcic chernozem) were collected from the upper 10?cm of paired arable land and secondary forests established 5 and 25 years previously. Carbon isotope analysis and pyrolysis–gas chromatography/mass spectrometry were used to determine SOC composition. The results show that (i) compared to the arable land, five years of afforestation caused a decrease in SOC and N concentration, while 25 years of afforestation resulted in an increase in SOC content; (ii) stable isotope δ¹³C analyses of the forest soils show gradual loss of crop-derived C and an accumulation of forest-derived C; and (iii) afforestation increased lignin abundance and decreased decompositional activity in the 25-year-old forest topsoil. Higher amounts of short-/mid-chain aliphatic compounds were observed in the 5-year-old forest (5–10?cm); and (iv) the arable soil contained substantially higher amounts of decomposed plant material and microbially derived substances. The results obtained suggest that long-term afforestation increases the SOC concentration, and alters the chemical composition of SOC.     

壳聚糖季铵盐的制备及其降尘性能研究

以壳聚糖为原料,对其季铵化改性制备了一种新型煤矿用环保降尘剂。主要包括单体3-氯-2-羟丙基三甲基氯化铵(CTA)的合成与壳聚糖季铵盐（HTCC）的制备。通过单因素试验研究了反应时间、反应温度、碱用量、单体配比等因素对HTCC降尘率的影响,并采用正交实验确定了最佳的工艺合成条件为:m(NaOH)/m(CTA)=1.2,m(CTA)/m(CTS)=3.5,60 ℃下反应10 h;用IR、XRD表征了HTCC。当HTCC投加量为0.4 g/L,pH=6、温度25 ℃时,煤尘去除率达到最大约为94.6%,在降尘领域中有着良好的应用前景。     

河北省衡水湖沉积物中汞的分布特征及生态风险

衡水湖是华北平原上第一个国家级内陆淡水湖泊湿地类型的自然保护区,为了解衡水湖沉积物中汞的分布特征及生态风险,于2013年8月在衡水湖采集了5根柱状沉积物,对其中的总汞、甲基汞、孔隙水溶解态汞、有机质、pH以及含水率进行了分析。结果表明,衡水湖沉积物中总汞的平均含量为22.5 ng·g-1,低于全国及河北省表层土壤背景值。但表层沉积物汞含量明显高于底层,说明近年来的外源汞输入对湖泊汞负荷产生了一定影响,且靠近湖泊东部106国道的采样点汞含量明显高于湖泊中西部的采样点,暗示交通运输等人为活动是该湖泊的一个重要汞输入源。利用潜在生态危害指数法进行评估,显示汞的生态风险较低,说明现阶段衡水湖的沉积物汞浓度不会对生态环境产生不利影响。     

Testing of chemical substances for environmental effects—an important task for the chemical industry

Recently the heterogeneous reactions are increasingly recognised as significant in polluted areas. In this work the reactions of gases with solid alkali‐halide crystals at temperatures 200K and 300K were examined by using a recently proposed thermodynamic model (Varotsos et al., 1988) which provides the interconnection of entropy and enthalpy for various processes with well known macroscopic properties of the bulk solid.     

Project Tocoen. the fate of selected pollutants in the environment. Part XIX. the phytotoxicity of organic and inorganic pollutants‐cadmium. The effect of cadmium on the growth of germinating maize plants

The effect of increasing cadmium concentration (10, 100 and 1000 μmol dm^‐3) on the growth, leaf area, content of assimilation pigments, cadmium content and the regulatory ability of the tissue of maize plants was investigated.

The results obtained document, already after 6 days, a significant decrease of dry weight, reduction of leaf area, chlorophyll a and b as well as carotenoids in plants grown in the nutrient solution containing 1000 μmol dm ^‐3 of cadmium. A highly significant inhibition of growth, leaf area and assimilation pigments in plants growing in the nutrient solutions with 100 and 10 μmol dm^‐3 of cadmium was registered after 17 days of cultivation. In plants growing in the nutrient solution containing 100 μmol dm^‐3 of cadmium a demonstrable reduction of the content of assimilation pigments was registered after 11 days of culture.

With increasing cadmium concentration in the nutrient solution as well as in the plant tissue after 6 and 17 days of culture both the range of the regulatory zone and the extent of optimum pH increased into the acid region. The pH values of the isoelectric point decreased with increasing cadmium content in the solution.