电磁环境对采后芒果的生理影响

系统研究了采后芒果在静电场,磁场,放电生成气环境下的生理变化。测试了呼吸速率,果体与果皮电解质渗出率,商品果率与病情指数等生理指标。研究结果表明,采后芒果在呼吸速率达到高峰之前电磁环境对其均有明显的作用,而在呼吸高峰之后,无明显影响。在我们设置的电磁环境参数中有几项显示保鲜作用。表１参６     

“一锅法”制备Ag/Fe_3O_4及其催化还原对硝基苯酚的性能

以硫酸亚铁和硝酸银为原料,水合肼作为助剂,采用"一锅法"制备了Ag/Fe_3O_4催化剂。用XRD对催化剂进行了表征。结果表明,催化剂中的Fe_3O_4为纯相,Ag在催化剂中分散较好,催化剂中Ag质量分数大于等于7%时会出现Ag的衍射峰。以硼氢化钠还原对硝基苯酚为模型反应,考察了Ag/Fe_3O_4催化剂的活性,Ag负载量为7%的Ag/Fe_3O_4具有较高的活性。催化剂具有较好的重复使用性,使用10次后活性有一定的下降。     

取代芳烃的自相关拓扑与其生物活性、性质的关系研究

本文提出表征原子生物活性的特征值（Ａｉ）,由Ａｉ建构自相关拓扑指数。其中１阶指数＾１Ｆ与氯代苯的８种理化性质的相关性优于Ｋｉｅｒ的＾１ｘ＾ｖ,＾１Ｆ与１７种取代芳烃ｌｇＫＯＷ的相关系数为０．９９４９,计算值与实验值非常吻合,取代芳烃对水生生物急性毒性与＾１Ｆ的线性回归方程如下：发光菌：－ｌｇＥＣ５０＝２．６７７＋０．０１５＾１ｆ,ｎ＝３０,ｒ＝０．９４３,ｓ＝０．２０５,保鲦鱼：－ｌｇＬＣ５０＝２     

长沙市城区施工扬尘和土壤扬尘污染时空特征研究

随着我国城市化的迅速发展,大气污染问题成为影响人们生活幸福感的重要因素之一。施工、裸露地面等引起的扬尘成为城市大气颗粒物污染的主要来源。将GIS方法和原环保部《扬尘源颗粒物排放清单编制技术指南(试行)》推荐的计算方法相结合,估算出2016—2018年长沙市城区施工扬尘源、土壤扬尘源的颗粒物排放量,从时空分布特征与空间自相关等多个方面剖析了扬尘源的颗粒物排放情况。结果表明:长沙市扬尘源沿中心城区向西、北方向辐射,呈现出半圆环形的带状分布,以城乡接合部最为集中；2016—2018年,长沙市城区扬尘源排放量总体呈现逐年递减的变化趋势。研究结果与长沙市城区实际情况基本相符,可为长沙市扬尘污染控制策略的制定提供参考。     

Combining STRIPAT model and gated recurrent unit for forecasting nature gas consumption of China

Mitigation and Adaptation Strategies for Global Change - With the orderly advancement of China Energy Development Strategic Action Plan, clean energy has become a major trend in the energy market....     

纳米氧化锌对羊角月牙藻毒性效应及其在藻细胞内外的分布

为研究纳米氧化锌(ZnO NP)的毒性效应及其在细胞内外分布,以羊角月牙藻(Selenastrum capricornutum)为模型藻类,研究了不同浓度ZnO NP对羊角月牙藻生长、叶绿素含量、可溶性蛋白含量、超氧化物岐化酶(SOD)及过氧化物酶(POD)活性、丙二醛(MDA)含量及细胞内外ZnO NP含量变化。结果表明,ZnO NP对羊角月牙藻的生长抑制与处理浓度呈现正相关。在45 mg·L~(-1)ZnO NP暴露24 h后,其生长抑制率已达到95%。当ZnO NP处理藻细胞72 h后,羊角月牙藻细胞的叶绿素含量与处理浓度之间存在剂量-效应关系。低浓度(0.5 mg·L~(-1))ZnO NP处理后藻细胞可溶性蛋白质含量、SOD和POD活性明显下降,MDA含量升高,其产生的毒性效应高于高浓度组(5 mg·L~(-1)、45 mg·L~(-1))。细胞培养液溶出Zn2+量及藻细胞外吸附的ZnO NP量与ZnO NP处理浓度成正比,但是藻细胞内ZnO NP量与ZnO NP浓度没有相关性,胞内积累量基本维持不变。研究表明,各浓度组对藻细胞毒性的差异,不仅与细胞内Zn2+量有关,还与细胞外粘附的ZnO NP有关。     

nano-TiO_2与1,2,4-TCB联合作用对斑马鱼鳃组织结构及染色体损伤研究

采用组织病理切片法、微核及彗星试验研究nano-TiO_2和1,2,4-TCB联合染毒对斑马鱼鳃组织结构、细胞微核率及DNA损伤的毒性效应。结果表明,单独nano-TiO_2暴露不会导致斑马鱼鳃组织结构损伤,也不会引起明显的微核及染色体损伤。1,2,4-TCB(≥10 mg·L~(-1))会引起鳃组织和细胞染色体的损伤。nano-TiO_2与1,2,4-TCB联合作用会加重斑马鱼的鳃组织结构损伤,出现鳃小片排列严重紊乱,表皮细胞断失严重,鳃小片上皮细胞坏死脱落,鳃丝结构模糊等症状。两者联合作用会引起鳃细胞微核率增加和彗星细胞率的增加,呈现一定的剂量-效应关系,且两者间的联合作用具有协同作用。对彗星试验的尾部DNA百分比、尾长及尾距的分析发现,与对照组和单独作用相比,两者联合作用对彗星指标均有显著增强作用,这表明两者联合作用对染色体的损伤属于非特定片段损伤。     

高效液相色谱荧光检测法测定大气中苯并[a]芘

采用反相高效液相色谱荧光检测法测定大气中苯并[a]芘含量。用甲醇超声提取采集在超细玻璃纤维滤膜上的苯并[a]芘,提取液注入反相高效液相色谱仪,通过C18反相色谱柱采用甲醇-水(体积比80比20)为流动相进行分离,采用荧光检测器进行检测,其激发波长为364nm,发射波长为427nm。分析同一溶液,测定结果的相对标准偏差(n=6)为4.6%。用标准加入法作回收试验,回收率结果在95.8%～101.7%之间     

Detecting pattern in biological stressor response relationships using model based cluster analysis

Environmental monitoring of aquatic systems is needed to estimate the quality of the systems, to evaluate standards and to study stressor–response relationships. Monitoring programs often focus on the collection of biological, chemical and physical measures of the system. An important concern is the effect of chemical and physical stressors on the biological community. Evaluation of relationships may be difficult as the extent of the relationship is not known. From a management perspective, interest is on what factors affect the biological community and where these factors have an influence. The focus of this paper is on the use of regression based cluster analysis as a tool for finding relationships between a single biological response and a suite of environmental stressors. The approach to cluster analysis uses a penalized regression classification likelihood and Markov Chain Model Composition Monte Carlo. This approach allows for simultaneous development of regression models and clustering of the regression models. The method is applied to the analysis of a data set describing stressors/response relationship in Ohio.     

Modelling the thresholds of nitrogen/phosphorus concentration and hydraulic retention time for bloom control in reclaimed water landscape

● A new model for bloom control in open land scape water was constructed. ● It considers the effects of temperature and light on algae growth. ● It describes threshold curve of nitrogen, phosp horus and hydraulic retention time. ● Light and temperature dependent growth para meters of typical algae were obtained. The risks posed by algal blooms caused by nitrogen and phosphorus in reclaimed water used in urban water landscapes need to be carefully controlled. In this study, the combined effects of the nitrogen and phosphorus concentrations and the light intensity and temperature on the specific growth rates of algae were determined using Monod, Steele, and Arrhenius models, then an integrated algal growth model was developed. The algae biomass, nitrogen concentration, and phosphorus concentration mass balance equations were used to establish a new control model describing the nitrogen and phosphorus concentration and hydraulic retention time thresholds for algal blooms. The model parameters were determined by fitting the models to data acquired experimentally. Finally, the control model and numerical simulations for six typical algae and mixed algae under standard conditions were used to determine nitrogen/phosphorus concentration and hydraulic retention time thresholds for landscape water to which reclaimed water is supplied (i.e., for a reclaimed water landscape).