垂直面绿化植物叶片遮阳系数的确定

在建筑物垂直面绿化研究中，考虑植物的叶片遮阳系数与农，林业中常用到的顺面积指数LAI不同，而是一个由叶片倾角，太阳光线入射角与叶面积指数决定的函数，在文中首次定义该影响系数为垂直面积植物叶片遮阳系数，推导求出该系数的函数定义关系式，测定了常用的攀缘类植物爬山虎的叶面积指数。     

Atmospheric PAH concentrations in fine and coarse particles

Measurements of the urban air concentrations of PAHsassociated with PM2.5-fine and PM10-coarse particles inChicago on the campus of IIT were achieved using a UniversalAir Sampler. Short sampling time (12 hr) and high flowrates were used to measure the PAH concentrations in fineand coarse particles. Measured ambient concentrations ofPAHs were classified based on wind direction and backtrajectory calculations as Land and Lake samples.Differences in ambient concentrations of PAHs were observedbetween Land and Lake samples. Fine particle concentrationsvaried from 9.5 to 25.7 ng m^-3 and averaged18.2 ng m^-3 for the Land samples, while they ranged from4.2 to 31.5 ng m^-3 and averaged 13.4 ng m^-3 for the Lake samples. The measured PAH concentrationsin coarse particles varied from 6.2 to 22.1 ng m^-3 and averaged 12.9 ng m^-3 for the Land samples, andthey ranged from 2.4 to 13.0 ng m^-3 with an average value of 7.3 ng m^-3 for the Lake samples. The fine/coarse ratio of each individual PAH compound varied between1.3 and 2.7 for the Land samples; it varied between 1.6 and 4.2 for the Lake samples. There was an increase in the fine/coarse ratio of PAH as molecular weight of the compound increases for both Land and Lake samples.     

新型动态膜预涂剂交联聚乙烯醇微球的制备及表征

提出用乳液聚合法制备交联聚乙烯醇(PVA)微球,使其吸附在膜表面实现膜的改性.通过聚乙烯醇(PVA)与戊二醛(GA)的乳化交联试验制备PVA微球粉末,并考察了W/O型乳状液内相的浓度、内外相体积比、乳化剂的性质和含量对形成稳定乳状液的影响.结果表明,当内相PVA水溶液浓度为2.7%、内外相体积比为40∶60、交联剂司盘-80的浓度为1.30 g/dL时,乳状液的稳定性好,形成的交联PVA微球满足需要.在乳化剂浓度足够的前提下,提高乳化机转速,制备的微球的粒径减小.随着理论交联度的提高,微球粒径有变小的趋势,而对Zeta电位影响不大.对制备的微球进行接触角、SEM和FTIR表征,考察了微球的亲水性、表面形态和交联反应对微球官能团的影响.     

软煤样断裂韧性加载速率效应实验研究*

为探究加载速率对软煤样Ⅰ型断裂韧性的影响,对取自云南老厂的煤样开展压入硬度实验及不同加载速率条件下的断裂韧性实验,分析加载速率及割理角度对软煤样断裂特性的影响。结果表明:实验老厂煤岩压入硬度分布在51.84～125.03 MPa之间,按压入硬度划分属于软岩类别;实验岩样Ⅰ型断裂韧性分布在0.009 9～0.208 2 MPa·mm^0.5之间,平均值为0.096 5 MPa·mm^0.5;在0.2～1.1 mm/min的位移加载速率范围内,实验软煤岩Ⅰ型断裂韧性值随加载速率的增大呈现先增大后降低的规律,割理角度对软煤岩Ⅰ型断裂韧性有较大影响,Ⅰ型断裂韧性与割理角度的关系呈现为负线性相关性。低加载速率条件下,软煤岩表现为韧性断裂,高加载速率条件下,软煤岩表现为脆性断裂,加载速率的变化导致软煤岩断裂类型的变化。     

Biosorption of Cu^2＋ and Zn^2＋ by raw and autoclaved Rocella phycopsis

The behavior of Cu2+ and Zn2+ biosorption onto raw and modified Roccella phycopsis from aqueous solutions was studied. Modification process was applied by autoclavation at 121°C for 30 min. The effcts of pH, initial metal concentration and biosorbent dosage were investigated. The maximum Cu2+ biosorption was achieved at pH 5.0 and the maximum biosorption capacities of 31.5 and 37.8 mg/g were recorded for raw and modified biosorbent, respectively. In the case of Zn2+ biosorption, maximum biosorption capacities were obtained at pH 4.0 as 29.1 and 35.3 mg/g for raw and modified biosorbent, respectively. Biosorption of Zn2+ and Cu2+ on all form of R. phycopsis increased much quickly with increasing initial metal concentrations from 10 to 100 mg/L. After modification process, probable changes in the surface polarity of raw and modified R. phycopsis were investigated by contact angle measurements. As expected, R. phycopsis has a polar surface and shows a highest contact angle with water, while after autoclavation water contact angle of R. phycopsis was significantly decreased from 47.5° to 34.4°.     

鄂尔多斯市1988-2000年土壤水力侵蚀与土地利用时空变化关系

土地利用是引起土壤侵蚀的重要驱动过程。基于1988年和2000年TM影像数据和气候、土壤、植被及DEM等数据,运用通用的土壤流失预报方程（RUSLE）,对鄂尔多斯市1988-2000年间的土壤水力侵蚀进行定量估算,揭示期间水力侵蚀的时空变化特点,并对土地利用类型与土壤侵蚀的关系进行分析。结果显示：1988-2000年间,研究区土壤水力侵蚀时空变化较为明显。时间变化上侵蚀强度明显减弱,除了微度侵蚀从53.16%剧增至81.24%以外,中度、强度、极强度和剧烈侵蚀类型均有较大幅度的下降;空间变化亦很明显,2000年与1988年相比,剧烈侵蚀只有准格尔旗东南部还有少量分布,强度侵蚀和极强度侵蚀主要分布在准格尔旗境内。土地利用方式对土壤侵蚀有明显的影响,高覆盖草地和水域的土壤侵蚀强度较小。此外,不同土地利用类型的平均土壤侵蚀模数和土壤强度指数均有大幅度的下降。其中未利用地的下降幅度最大（68.14%）,其次为低覆盖度草地（64.09%）,耕地的下降幅度最小（49.62%）。研究结果表明,鄂尔多斯土壤水力侵蚀治理的重点区域是东北部,改变土地利用方式,增加水土保持工程措施,加强采矿迹地的修复重建等是有效防治土壤水力侵蚀的重要措施。     

旋风除尘器灰环磨损与锥体角度关系的研究

提出在普通锥体型旋风除尘器中,回转性灰环是造成锥体部位磨损的重要原因之一.通过对锥体内粉尘颗粒的受力分析,从理论上推导出了减低灰环磨损的锥体角度的表达式.通过对理论分析提出了旋风除尘器锥体设计中应注意的问题,为旋风除尘器的设计提供一定的参考依据.     

有机硅提高除草剂在紫茎泽兰叶片上润湿性能的研究

市售的氨氯吡啶酸与甲嘧磺隆制剂用四川省西昌市当地自来水稀释1250、2500、5000、10000和625、1250、2500、5000倍后,得到的药液的表面张力大于紫茎泽兰的临界表面张力,药液滴与紫茎泽兰叶片的接触角在接触4min后仍为50°～70°。虽然氨氯吡啶酸和甲嘧磺隆对紫茎泽兰（Eupatorium adenophorum Spreng）防除效果较好,可喷药后药剂不容易被植物持留,造成巨大浪费和当地的环境污染。从农药应用角度来看,这两种农药制剂中表面活性剂存在不合理性。笔者通过添加有机硅表面活性剂,探索合理的有机硅添加浓度,减小氨氯吡啶酸、甲嘧磺隆与紫茎泽兰叶片的接触角,改善该药剂对紫茎泽兰叶片润湿性,提高其利用率,减少损失,避免环境污染。文章测定了有机硅临界胶束浓度、紫茎泽兰临界表面张力及添加不同浓度有机硅药液的表面张力,得到有机硅质量分数大于等于0．05％（有机硅临界胶束浓度）,药液即可以在叶面铺展的结论。通过有机硅添加量与药液铺展速率的关系的测定,得到结论：有机硅添加质量浓度达到0．05％时,添加浓度越大,铺展速率越大。     

Spatial and temporal patterns of soil erosion in the Tibetan Plateau from 1984 to 2013北大核心CSCD

Soil erosion has a critical effect on ecological security and socioeconomics, which may deteriorate ecosystem services and common human well-being. The revised universal soil loss equation (RUSLE) was applied to assess soil erosion from 1984 to 2013 in the Tibetan Plateau and analyzed the temporal and spatial variation of soil erosion intensity. Furthermore, the temporal and spatial variation rates of soil erosion were explored across different ecosystems. The results indicated that the annual soil erosion fuctuated in the Tibetan Plateau, the soil erosion intensity decreased from south to north, and the most serious soil erosion was mainly distributed in the southern Tibetan Plateau (Xigaze and Changdu regions, Lhasa, and north of the Shannan region). The soil erosion intensity was higher in shrub, alpine meadow, and sparse vegetation ecosystems. The highest soil erosion was found in alpine meadow (2.17 × 1010 t), followed by alpine grassland (1.59 × 1010 t) and sparse vegetation (1.30 × 1010 t) ecosystems. Meanwhile, although the most serious soil erosion intensity was found in the regions of 3 000-4 000 m altitude, the soil erosion was mainly observed in the regions of 4 000-5 000 m altitude. In the three most recent decades, annual soil erosion decreased at a rate of-1.78 × 108 t/a. Additionally, soil erosion mainly increased in south of the Qiangtang Plateau and in the periphery of the Qaidam basin. Decreased soil erosion was mainly found along the Hengduan Mountains, central Himalayas. Although the increased annual normalized difference vegetation index (NDVI) had positive effects for soil protection, changes in soil erosion was mainly controlled by the change of annual precipitation. Thus, the fragility of ecological systems and increased rainfall erosivity accounted for the obviously increased soil erosion in the alpine grassland ecosystem (1.19 × 10 t/a). However, increased ecosystem stability and decreased rainfall erosivity contributed to the decreased soil erosion in forest and shrub ecosystems, by-0.77 × 10 t/a and-1.65 × 10 t/a, respectively. The slightly decreased rainfall erosivity accounted for a decrease of soil erosion in the sparse vegetation ecosystem (-0.44 × 10 t/a). Meanwhile, soil erosion has decreased in the alpine meadow ecosystem over the past 30 years, which may owing to the relatively higher NDVI that neutralized the increase of rainfall erosivity to some extent. This study revealed serious soil erosion regions and ecosystems in the Tibetan Plateau and explored possible reasons for variations in soil erosion in different ecosystems, which may provide a scientific reference for soil erosion conservation and control in the near future. © 2018 Science Press. All rights reserved.