两种矿山生态型香薷对铜的吸收、分布和积累特性研究

Two ecotypes of Elsholtzia, Elsholtzia splendens and E. argyi, are dominant plants growing on Cu and Pb-Zn smelters, respectively. Samples of the two ecotypes and the corresponding soils from fields of a copper mining area and a Pb-Zn mining area of Zhejiang Province, China, were analyzed to investigate Cu or Zn tolerance of these two ecotypes. Effects of nine Cu levels (0, 5, 10, 20, 40, 80, 160, 240 and 320 mg Cu L^-1 as CuSO₄·5H₂O) on growth and uptake, translocation and accumulation of Cu in these two ecotypes were examined in a solution culture experiment. The experimental results showed that dry weights (DW) of shoots and roots were depressed, and growth of E. splendens was less depressed than that of E. argyi when treated with ≥ 5 mg Cu L^-1. Concentrations of Cu in shoots of E. splendens and E. argyi exceeded 1 000 mg kg^-1 DW at ≥ 40 mg Cu L^-1. The maximum Cu accumulated in the shoots of Cu-treated E. splendens and E. argyi reached 101 and 142 μg plant^-1. Furthermore, analysis of plant samples from the fields showed that these two ecotypes can tolerant excess heavy metals and produced high dry matter, and E. splendens can accumulate 11.7 mg Cu plant^-1 grown on the Cu smelter. Therefore, E. splendens and E. argyi could be good plants for phytoremediation.     

二冲程发动机润滑油成份对燃烧室堆积物的影响分析

二冲程发动机的燃料和润滑油同时燃烧是造成燃烧室堆积现象严重的主要原因,其中润滑油中的不同成分对燃烧室堆积物的影响程度不同,本文依据静态模拟实验,重点研究润滑油中的各成份对燃烧室堆积物生成的影响,从而给改善燃烧堆积物的堆积状况带来可靠的理论研究依据。     

刷牙时宜常刮舌苔

<正>医学上,舌苔有白苔、黄苔、腻苔、黑苔等之分。正常人舌苔薄白,烟酒嗜好者舌苔较厚,患病时舌苔又会有所变化。中医认为,舌苔是胃气生发形成的;西医则认为舌苔是脱落的上皮细胞、黏液和少许食物残渣在舌表面形成的堆积物。舌苔     

佳联-3系列收割机常见故障及排除方法

<正>联合收割机在使用过程中,由于零件磨损、变形,使用和保养不当等原因引起各部分技术状态逐渐变化,当某些技术指标超出允许限度时,就表明机器已有了故障。联合收割机出现故障后,如不及时正确地予以排除,会使联合收割机不能正常发挥效能或导致有关零件的损坏,只有细心地观察联合收割机的运转情况和发生故障的特征,才能正确判断故障的原因。在故障原因不清的情况下,不应盲目拆修;维修工作应由专业或熟练的维修人员进行或在场指导完成。     

黄土高原沟壑区土壤侵蚀评价指标体系——以中国王东沟流域为例

The Wangdonggou Watershed on the Loess Plateau in China was selected as the study area to develop a model for soil erosion assessments. Using the data collected at 20 sampling sites all tentatively selected indicators were assessed against their corresponding erosion intensity through a correlation analysis. Eight highly correlated indicators were then chosen for the soil erosion assessment. In addition, threshold limits to delineate the class size for these indicators and weights to rank them were determined. Next, a grading model incorporating the selected indicators class rating and their associated weights was developed and verified by an on site evaluation of the soil erosion intensity in the study area. Results of the verification showed that the overall accuracy of the indicator system for assessing soil erosion in the Loess Plateau gully regions could reach 85%.     

积造优质有机肥4法

一、警通堆肥法。 在田边、地头或宅旁,挖深1米、宽2—3米的长方形坑,利用碎麦秸、麦糠、青草、垃圾等物,加入人畜粪尿和泥土进行堆积。坑底先撒5厘米厚泥土,然后填入堆积物,每增高20厘米加适量水和5厘米厚的泥土,层层堆积至满坑为止。经过2个月堆积物便充分腐熟可以施用。堆肥腐熟的标志：体积显著变小,     

冰川、冻土地貌与堆积物

地球历史上,第四纪曾有大规模的冰川活动.它严重的影响地表的自然状况和生物生存环境、海陆分布以及外力地质作用的进行.第四纪时期.冰期和间冰期几度交替出现.深刻地影响着土壤的特性,以致它们形成的土壤彼此间在生产上也有一些显著差异.     

动床模型试验中存在问题的辨析

在动床模型试验中，一般用散粒料来模拟受冲刷的岩基，造成模型河床的糙率偏大、河床潜流影响严重等问题，使得模型测试的水面线与实际水面有一定偏差。本文根据近年来笔者做的几个动床模型，阐述了动床试验存在的几个问题，以及由此产生的模型测试方面的某些误差，并对模型试验的准确性进行了论述，以期对同类模型试验提供借鉴。