Analysis of spatial and temporal changes of vegetation cover and its driving forces in the Huainan mining area

Environmental Science and Pollution Research - The Huainan mining area is rich in coal resources and has sparse vegetation and many collapsed waterways. Large-scale and long-term underground coal...     

Coexistence of Cr and Ni in anthropogenic soils and their chemistry: implication to proper management and remediation

Environmental Science and Pollution Research - In anthropogenic soils, there have been relatively limited studies focusing on Cr and Ni contaminants because they exhibit less toxic effects to...     

Macroeconomic lockdown effects of COVID-19 on small business in China: empirical insights from SEM technique

The coronavirus (COVID-19) outbreak in the China has exposed small- and medium-sized enterprises (SMEs) to a variety of challenges, some of which are potentially life-threatening to their sustainability. Therefore, this study aims to investigate the macroeconomic lockdown effects of COVID-19 on small business in China. A survey questionnaire with 313 participants was used to collect the data. In this study, the SEM technique was used to analyse model. The data have been gathered for the study from the managers and employees of Chinese SMEs. The findings of the study show that COVID-19 has a significant negative impact on financial performance, operational performance, profitability, access to finance, and customer satisfaction. According to the study's findings, external support aids have a greater impact on SMEs' ability to survive and thrive through innovation than on their actual performance. The findings of this study have a number of important practical consequences for small- and medium-sized business owners, governments, and policymakers.

     

Constructing 3D magnetic flower-like Fe3O4@SiO2@Co3O4@BiOCl heterojunction photocatalyst for degrading rhodamine B

Environmental Science and Pollution Research - In this work, the 3D magnetic flower-like Fe3O4@SiO2@Co3O4@BiOCl heterojunction photocatalyst was successfully prepared. The combination of BiOCl with...     

A global comprehensive analysis of ambient low temperature and non-communicable diseases burden during 1990–2019

Environmental Science and Pollution Research - Climate change and health are inextricably linked, especially the role of ambient temperature. This study aimed to analyze the non-communicable...     

海洋破囊壶菌△~5-延长酶和△~4-脱饱和酶在酿酒酵母中的共表达

二十二碳六烯酸(Docosahexaenoic acid,DHA C22:6n-3)是具有各种重要生理功能的高度不饱和脂肪酸.分别以质粒pYTFD5和pYFAD4为模板,扩增获得860 bp的△5-延长酶基因(elo5)和1 600 bp的△4-脱饱和酶基因(fad4).利用重叠延伸PCR构建elo5-fad4融合基因,Hind Ⅲ/Sph Ⅰ双酶切后连接到经同样处理过的pYES2.0载体,构建重组表达质粒pYEL05-FAD4.转化酿酒酵母尿嘧啶缺陷型菌株INVScl,通过缺少尿嘧啶的选择性培养基筛选阳性克隆子.添加外源脂肪酸C20:5底物.半乳糖诱导表达.气相色谱-质谱分析表明,重组酵母总脂肪酸中出现了DHA(二十二碳六烯酸,C22:6n-63)新产物,融合基因elo5-fad4在酿酒酵母中得到了表达.图7表1参18     

广西南部地区坡地桉树生长与气象因子的关系

采用偏相关、典型相关分析等方法,对广西南部地区2.5万hm2 2～8 a生桉树(Eucalyptus)的平均胸径、平均树高、单位蓄积量等生长指标与该地区的气象因子的关系进行分析,研究制约坡地桉树生长的主要因素.结果表明:(1)该地区桉树生长与气候因子间存在着较密切的相关关系,其中成年桉树的树高和单位蓄积量生长主要受最冷月平均气温、年平均气温和年降雨量的影响;(2)胸径生长受气象因子的影响较小;(3)4 a生桉树受最冷月气温、年平均气温影响较大;(4)2 a生桉树幼林平均胸径与最冷月平均气温呈极显著正相关,而与年平均气温、年降雨量呈显著正相关关系; (5)尽管降水量丰富,但由于坡地特殊的地形,年降水量仍然是制约广西南部坡地桉树人工林的主要限制因子;(6)广西南部地区太阳辐射较大,不是制约桉树生长的主要因素,故在采用3-PG模型预测桉树生长状况时,太阳辐射不是关键参数.     

Contributing institutional factors of rural environmental pollution in the process of modernization in China —In the perspective of the efficiency of environmental management system

With the development of rural pollution, its characteristic and institutional factor should be studied for pollution control through economics and sociology. Based on the data gathered from investigations by several government sectors, rural environmental pollution can be divided into two types by its sources: internal source type and external source type. The internal source type is the main component of rural pollution at present, which can be further divided into three types. Research shows that the contributing institutional factors of rural pollution issues and the effectiveness of environmental management system over rural pollution can be summarized as distinctiveness. In essence, the rural pollution issue results from the dualism of rural and urban areas’ inadaptability to rural modernization. In detail, the contributing factors can be summed up on three institutional levels. There are obvious loopholes in rural environmental management system which, in the meantime, is incapable and inadaptable to rural pollution control. There exist similar questions in the related public service system, which are intensified by inappropriate reform which brought about incompatible incentive in the recent years. However, in the eleventh five-year plan period, there are advantageous trends in the three institutional levels.     

β-环糊精微球吸附对苯二酚单甲基醚的动力学研究

研究了以β-环糊精(β-CD)和环氧氯丙烷为原料,采用反相悬浮聚合法合成的β-CD微球对对苯二酚单甲基醚( HQMME)的静态吸附行为,分析了吸附热力学性质和动力学特征.实验结果表明:β-CD微球对HQMME的吸附过程同时符合Lagergren一级吸附动力学方程和McKay二级吸附动力学方程;β-CD微球对HQMME的吸附等温线可同时用Langmuir等温吸附方程和Freundlich等温吸附方程描述;在不同温度下,β-CD微球吸附HQMME的吸附焓变、吸附熵变、吸附吉布斯自由能变均为负值,说明吸附是一个自发、放热的过程.     

风速测量仪器的动力学性能研究

探讨了几种风速测量仪器的测头平面法线和来流方向成某一角度时 ,产生的测量偏差的大小