Adsorption characteristics of a phenoxy acetic acid herbicide on activated carbon

The adsorption of 2,4-dichlorophenoxyacetic acid (2,4-D) by two powdered coal activated carbons was studied in aqueous solution. The modelling of the adsorption equilibrium showed that the adsorption of 2,4-D fitted a Langmuir isotherm. Adsorption was influenced by the activated carbon type, adsorbent concentration and solution characteristics. The adsorption was found to decrease with an increase in pH over the range 1.5-9. Maximum adsorption occurred at pH approximately 2.5, which corresponds to the 2,4-D pKa value. The amount of 2,4-D adsorbed was also found to depend on the NaCl concentration.     

蚌埠市龙子河水生生物现状调查及分析

经监测调查，龙子河水体水生生物资源丰富。浮游植物有７门近百种，主要有绿藻类，硅藻类、蓝藻类、浮游动物主要有桡足类，枝角类，轮虫类等；底栖动物主要是蚌，螺类，水丝蚓等２１种。     

苏州市近地面臭氧时空分布特征及模拟分析

文章利用2016-2019年苏州市臭氧(O₃)环境监测站点数据,分析了苏州市O₃浓度的时空分布特征及其与NO₂、CO的相关性,并利用WRF-Chem模式模拟了苏州地区O₃高浓度事件来探究湖陆风对O₃迁移的影响。结果表明：苏州市O₃明显超标且2017年超标最为严重;O₃污染日具有明显的季节特征,以O₃作为首要污染物在春夏季尤为突出;月变化呈现双峰型特征,前2年峰值出现时间要略早于后2年;各季节日变化均为单峰型特征,在15:00前后浓度达到最高;空间上市区浓度整体高于周边城市,但在湖陆风盛行的2017年夏季截然相反;苏州市夏季存在明显的O₃“周末效应”,周末的夜间和上午O₃浓度高于工作日,而工作日在O₃峰值时段浓度更高;模拟的O₃高浓度事件证明了太湖湖陆风的存在,而高温时段湖风会将城区O₃往下风向的周边城市移...     

战略环境评价系统及工作程序

介绍了战略环境评价系统组成的五个要素 ,即评价者、评价对象、评价目的、评价标准和评价方法 ,分析了其相互关系及各要素与战略环境评价系统的关系 ,并提出了战略环境评价工作程序。     

Invasion of Pinus halepensis Mill. following a wildfire in an Argentine grassland nature reserve

The Ernesto Tornquist nature reserve is a relict of native Pampas vegetation in Argentina. Alien trees were introduced to the reserve in the 1950s, mainly to "improve" the natural landscape, resulting in the arrival of a totally new life form. In 1987, a fire affected an area planted with Pinus halepensis resulting in its massive expansion. In 1999, we removed trees from 17 circular plots of 10 m diameter placed systematically within the area that was colonized after the fire. Trunks were cut 20 cm from the ground and growth rings were counted. We studied the age structure of the population in order to reconstruct the colonizing events after the fire. We found that recruitment occurred throughout this period, except in the three years after the disturbance. We suggest that this delay in recruitment might be caused by low seedling survival under water stress conditions due to low rainfall, combined with scarce vegetation cover after fire. This could have been associated with an initial reduction in propagule pressure due to the scarcity of surviving trees in the vicinity and with the fact that fire occurred after the peak of seed release, during an extremely dry summer, probably killing a great number of seeds that were already in the soil. In the following years, recruitment was probably aided by pioneer trees and later by seeds shed from established pines. Alien trees had been allowed to reach maturity due to wildfire prevention and control in the years preceding the fire and the accumulated dry matter resulted in increased fire intensity that reduced the ability of grasses to re-sprout. As a consequence, the invasion window that allowed the expansion of pines remained open for at least 12 years.     

归绍文研制成功微机校验台

湖北襄樊市第二汽车制造厂仪表厂助理技师归绍文经过多年刻苦攻关,研制成功了微机校验台,为使汽车仪表装配工人消除传统生产方式造成的视觉疲劳提供了条件。 在这以前,该厂校验汽油、油压、水温三种仪表的校验台是指针式的标准表。校验时,要求表面显示必须是“三条线成一线”。为了保证精度,工人的眼睛必须一动不动地盯着刻度指针,时间久了,眼睛又酸又胀,以致头痛头晕。这样的工作,年轻工人在视力正常情况下还可以坚持,但一近中年,由于视力减退,就不得不改换工种了。 为了改变校验工人的劳动条件,归绍文下决心改制日的校验台。从1978年开始,…     

一截手指

湖北二汽车厢分厂工具科有个女工违章作业伤了手指。郧阳地区医院的大夫提出要锯掉一截手指。 党委书记芦廷寅考虑到这样会影响她以后的工作和生活,就亲自陪这位女工到第一职工医院,要求医生尽可能保全这根手指。后来,经医生缝合后保全了这根手指。老芦趁热打铁,对那位女工进行教育,讲明不重视安全给国家造成损失,给本人带来痛苦的严重危害,说得那位女工感动地流下了热泪。一截手指@包建威 @张舜贤