检索结果-南通市图书馆

Journal of Wuhan University of Technology(Materials Science) 2009年第4期24卷 581-587页

作者：张凌燕魏婷婷 college of resource and environment engineering Wuhan University of Technology

The mechanical and thermal properties of polypropylene （PP）/muscovite/ low-density polyethylene （LDPE）/ polypropylenegraftmaleic anhydride （PP-g-MAH） ternary composites were investigated. In PP matrix, muscovite, LDPE, and PP-g-MAH were added as strengthening agent, toughening agent, and compatibilizer, respectively. The effects of dosages of the added materials were analyzed. The - experimental results show that the optimum recipe of PP/muscovite/LDPE/PP-g-MAH composites is 100/10/6/20 （mass ratio）. Compared with the pure PP, the mechanical properties of PP/muscovite/LDPE/PP-g-MAH composites, including notched impact strength, Rockwell hardness and flexural strength, are improved. Although tensile strength is slightly decreased, they have better toughness. Filled with muscovite, the heat-resistance and heat-decompostion of the composites are improved.

关键词： PP LDPE muscovite reinforcement and toughening

Coking wastewater increases micronucleus frequency in mouse in vivo via oxidative stress

在线全文

学校读者我要写书评

暂无评论

Journal of environmental Sciences 2013年第10期25卷 2123-2129页

作者： Na Zhu Hongyan Li Guangke Li Nan Sang college of environment and resource Center of Environmental Science and Engineering Shanxi University

Coking wastewater has caused serious health risk in coal-producing areas of China, however its toxic effects have not been well understood. The genotoxicity induced by coking wastewater on mice in vivo and its possible oxidative mechanisms were investigated via observing the induction of micronuclei in polychromatic erythrocytes of mouse bone marrow, and subsequently determining the antioxidative enzyme activities （superoxide dismutase Cu, Zn-SOD, Se-dependent glutathione peroxidase, and catalase）, thiobarbituric acid reactive substance contents and protein carbonyl levels in brains and livers of mice. Results showed that the tested coking wastewater caused a significant increase of micronucleus frequencies in a concentration-dependent manner. Also, the sample increased lipid peroxidation and protein oxidation levels, which was accompanied by changes in antioxidative status. Interestingly, pre-treatment with an antioxidant （vitamin C） led to a statistical reduction in the micronucleus frequency caused by coking wastewater. This implies that coking wastewater induces evident genetic damage in mammalian cells, and exposure to polluted areas might pose a potential genotoxic risk to human beings; in the process, oxidative stress played a crucial role.

关键词： micronucleus oxidative stress coking wastewater mouse bone marrow

Effects of nitrogen dioxide and its acid mist on reactive oxygen species production and antioxidant enzyme activity in Arabidopsis plants

在线全文

学校读者我要写书评

暂无评论

Journal of environmental Sciences 2015年第8期27卷 93-99页

作者： Xiaofang Liu Fen Hou Guangke Li Nan Sang college of environment and resource Research Center of Environment and Health Shanxi University college of environmental Science and engineering Nankai University

Nitrogen dioxide（NO2） is one of the most common and harmful air pollutants. To analyze the response of plants to NO2 stress, we investigated the morphological change, reactive oxygen species（ROS） production and antioxidant enzyme activity in Arabidopsis thaliana（Col-0） exposed to 1.7, 4, 8.5, and 18.8 mg/m3NO2. The results indicate that NO2 exposure affected plant growth and chlorophyll（Chl） content, and increased oxygen free radical（O2-）production rate in Arabidopsis shoots. Furthermore, NO2 elevated the levels of lipid peroxidation and protein oxidation, accompanied by the induction of antioxidant enzyme activities and change of ascorbate（As A） and glutathione（GSH） contents. Following this, we mimicked nitric acid mist under experimental conditions, and confirmed the antioxidant mechanism of the plant to the stress. Our results imply that NO2 and its acid mist caused pollution risk to plant systems. During the process, increased ROS acted as a signal to induce a defense response, and antioxidant status played an important role in plant protection against NO2/nitric acid mist-caused oxidative damage.

关键词： Nitrogen dioxide Nitric acid mist Arabidopsis thaliana Reactive oxygen species Antioxidant system

Constitutive model for casting magnesium alloy involving spherical void evolution

在线全文

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 2008年第A01期18卷 175-179页

作者：陈斌彭向和范镜泓孙士涛 Department of engineering Mechanics College of Resource and Environment ScienceChongqing University

Casting magnesium alloys are highly heterogeneous materials inevitably containing numerous *** voids will evolve during material deformation and markedly affect material behaviors,so it is important to investigate the equation of the void evolution and the constitutive relation involving the void *** assuming the voids in casting magnesium alloys were spherical,the growth equation of the voids was obtained from the incompressibility and continuity conditions of material matrix. Through combining the obtained void-growth equation with the void-nucleation equation relative to the increment of intrinsic-time measure,the evolution equation of the voids was *** introducing the presented void-evolution equation to a nonclassical elastoplastic constitutive equation,a constitutive model involving the void evolution was put *** corresponding numerical algorithm and finite element procedure of the model were developed and applied to the analysis of the elastoplastic response and the porosity change of casting magnesium alloy *** results show satisfactory agreement with those of the corresponding experiments.

关键词：镁合金压铸铸件饱和多孔介质

Electrochemical corrosion of steel balls in wet grinding

在线全文

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 2003年第4期13卷 958-962页

作者：谢恒星李松仁李定或 college of resource and environment engineering School of resources Processing and Bioengineering Department of Mineral engineering

Rest potentials for the steel ball electrode and the pyrite electrode as well as the combination potentials and the galvanic currents developed in the pyrite steel ball couple were measured. The data demonstrate that the galvanic couples are going to form between the pyrite particles and the steel balls when they contact with each other. The initial combination potential and the initial galvanic current of the pyrite ball couple while bubbling with oxygen are greater than those in aeration of air. The combination potential and the galvanic current decrease more quickly with time while bubbling with oxygen than they do in aeration of air. In an experiment of simulating wear differences, a galvanic current, which is smaller than that developed in the pyrite ball couple, exists between two different ball electrodes in wear degree on the surface of them. Under different grinding time conditions, the equivalent corrosion current density calculated from marked ball wear data by applying Faraday’s law correlates well with those estimated from polarization curves of pyrite and ball electrodes, and the former is always greater than the latter.

关键词：磨矿电化学腐蚀钢球球磨机选矿

Modeling of acute cadmium toxicity in solution to barley root elongation using biotic ligand model theory

在线全文

学校读者我要写书评

暂无评论

Journal of environmental Sciences 2016年第4期28卷 112-118页

作者： Xuedong Wang Mingyan Wu Jingxing Ma Xiaolin Chen Luo Hua The Key Lab of resource environment and GIS College of Resource Environment and TourismCapital Normal University

Protons（H^＋）as well as different major and trace elements may inhibit cadmium（Cd）uptake in aquatic organisms and thus alleviate Cd ***,little is known about such interactions in soil *** this study,the independent effects of the cations calcium（Ca^2＋）,magnesium（Mg^2＋）,potassium（K^＋）,H^＋ and zinc（Zn^2＋）on Cd toxicity were investigated with 5-day long barley root elongation tests in nutrient *** tested concentrations of selected cations and trace metal ions were based on the ranges that occur naturally in soil pore *** toxicity of Cd decreased with increasing activity of Ca^2＋,Mg^2＋,H^＋and Zn^2＋,but not K^＋.Accordingly,conditional binding constants were obtained for the binding of Cd^2＋,Ca^2＋,Mg^2＋,H^＋,and Zn^2＋ with the binding ligand：log K（CdBL）5.19,logK（CaBL）2.87,logK（MgBL）2.98,logK（HBL）5.13 and logK（ZnBL）5.42,***,it was calculated that on average 29% of the biotic ligand sites needed to be occupied by Cd to induce a 50% decrease in root *** the estimated constants,a biotic ligand model was successfully developed to predict the Cd toxicity to barley root elongation as a function of solution *** feasibility and accuracy of its application for predicting Cd toxicity in soils were discussed.

关键词： Cadmium Biotic ligand model (BLM) Toxicity Barley

Synergistic effects of particulate matter(PM_10) and SO_2 on human non-small cell lung cancer A549 via ROS-mediated NF-κB activation

在线全文

学校读者我要写书评

暂无评论

Journal of environmental Sciences 2015年第5期27卷 146-153页

作者： Yang Yun Rui Gao Huifeng Yue Guangke Li Na Zhu Nan Sang college of environment and resource Research Center of Environment and Health Shanxi University

Since a real atmospheric scenario usually represents a system involving multiple pollutants, air pollution studies typically focused on describing adverse effects associated with exposure to individual pollutants cannot reflect actual health risk. Particulate matter（PM10） and sulfur dioxide（SO2） are two major pollutants derived from coal combustion processes and co-existing in coal-smoke air pollution, but their potentially synergistic toxicity remains elusive thus far. In this study, we investigated the cytotoxic responses of PM10 and SO2, singly and in binary mixtures, using human non-small cell lung cancer A549 cells, followed by clarifying the possible mechanisms for their interaction. The results indicated that the concomitant treatment of PM10 and SO2 at low concentrations led to synergistic injury in terms of cell survival and apoptosis occurrence, while PM10 and SO2 alone at the same concentrations did not cause damage to the cells. Also, radical oxygen species（ROS） production followed by nuclear factor kappa B（NF-κB） activation was involved in the above synergistic cytotoxicity, which was confirmed by the repression of the actions by an ROS inhibitor（NAC）. This implies that assessment of health risk should consider the interactions between ambient PM and gaseous copollutants.

关键词： PM10 SO2 Synergistic toxicity ROS NF-κB

Particulate matter(PM(2.5)) exposure season-dependently induces neuronal apoptosis and synaptic injuries

在线全文

学校读者我要写书评

暂无评论

Journal of environmental Sciences 2017年第4期29卷 336-345页

作者： Minjun Chen Ben Li Nan Sang college of environment and resource Research Center of Environment and HealthShanxi University

Epidemiological studies have shown that particulate matter 2.5（PM（2.5）） not only increases the incidence of cardiopulmonary illnesses but also relates to the development of neurodegenerative diseases. Considering that PM（2.5）is highly heterogeneous with regional disparity and seasonal variation, we investigated whether PM（2.5）exposure induced neuronal apoptosis and synaptic injuries in a season-dependent manner. The results indicated that PM（2.5）altered the expression of apoptosis-related proteins（mainly bax and bcl-2）, activated caspase-3 and caused neuronal apoptosis. Additionally, PM（2.5）decreased the levels of synaptic structural protein postsynaptic density（PSD-95） and synaptic functional protein N-methyl-D-aspartate（NMDA） receptor subunit（NR2B） expression. These effects occurred in a season-dependent manner, and PM（2.5）collected from the winter showed the strongest changes. Furthermore, the effect was coupled with the inhibition of phosphorylated extracellular signal-regulated kinase 1/2（p-ERK1/2） and phosphorylated c AMP-response element binding protein（p-CREB）. Based on the findings, we analyzed the correlations between the chemical composition of PM（2.5）samples and the biological effects, and confirmed that winter PM（2.5）played a major role in causing neuronal apoptosis and synaptic injuries among different season samples.

关键词： Particulate matter(PM(2.5)) Season-dependent effect Neuronal apoptosis Synaptic injury

Multiple Tin Compounds Modified Carbon Fibers to Construct Heterogeneous Interfaces for Corrosion Prevention and Electromagnetic Wave Absorption

在线全文

学校读者我要写书评

暂无评论

Nano-Micro Letters 2025年第1期17卷 507-527页

作者： Zhiqiang Guo Di Lan Zirui Jia Zhenguo Gao Xuetao Shi Mukun He Hua Guo Guanglei Wu Pengfei Yin college of Science Sichuan Agricultural UniversityYa’an 625014People’s Republic of China School of Materials Science and engineering Hubei University of Automotive TechnologyShiyan 442002People’s Republic of China Institute of Materials for Energy and environment State Key Laboratory of Bio‑Fibers and Eco‑TextilesCollege of Materials Science and EngineeringQingdao UniversityQingdao 266071People’s Republic of China Shaanxi Key Laboratory of Macromolecular Science and Technology School of Chemistry and Chemical EngineeringNorthwestern Polytechnical UniversityXi’anShaanxi 710072People’s Republic of China

Currently,the demand for electromagnetic wave(EMW)absorbing materials with specific functions and capable of withstanding harsh environments is becoming increasingly ***-component interface engineering is considered an effective means to achieve high-efficiency EMW ***,interface modulation engineering has not been fully discussed and has great potential in the field of EMW *** this study,multi-component tin compound fiber composites based on carbon fiber(CF)substrate were prepared by electrospinning,hydrothermal synthesis,and high-temperature thermal *** utilizing the different properties of different substances,rich heterogeneous interfaces are *** effectively promotes charge transfer and enhances interfacial polarization and conduction *** prepared SnS/SnS_(2)/SnO_(2)/CF composites with abundant heterogeneous interfaces have and exhibit excellent EMW absorption properties at a loading of 50 wt%in epoxy *** minimum reflection loss(RL)is−46.74 dB and the maximum effective absorption bandwidth is 5.28 ***,SnS/SnS_(2)/SnO_(2)/CF epoxy composite coatings exhibited long-term corrosion resistance on Q235 steel ***,this study provides an effective strategy for the design of high-efficiency EMW absorbing materials in complex and harsh environments.

关键词： Electrostatic spinning Component regulation Heterogeneous interfaces Electromagnetic wave absorption Corrosion protection

Effects of cadium, zinc and lead on soil enzyme activities

在线全文

学校读者我要写书评

暂无评论

Journal of environmental Sciences 2006年第6期18卷 1135-1141页

作者： YANG Zhi-xin LIU Shu-qing ZHENG Da-wei FENG Sheng-dong college of resource and environment China Agricultural University Beijing 100094 China college of resource and environment Agricultural University of Hebei Baoding 071001 China

Heavy metal （HM） is a major hazard to the soil-plant system. This study investigated the combined effects of cadium （Cd）, zinc （Zn） and lead （Pb） on activities of four enzymes in soil, including calatase, urease, invertase and alkalin phosphatase. HM content in tops of canola and four enzymes activities in soil were analyzed at two months after the metal additions to the soil. Pb was not significantly inhibitory than the other heavy metals for the four enzyme activities and was shown to have a protective role on calatase activity in the combined presence of Cd, Zn and Pb; whereas Cd significantly inhibited the four enzyme activities, and Zn only inhibited urease and calatase activities. The inhibiting effect of Cd and Zn on urease and calatase activities can be intensified significantly by the additions of Zn and Cd. There was a negative synergistic inhibitory effect of Cd and Zn on the two enzymes in the presence of Cd, Zn and Pb. The urease activity was inhibited more by the HM combinations than by the metals alone and reduced approximately 20%--40% of urease activity. The intertase and alkaline phosphatase activities significantly decreased only with the increase of Cd concentration in the soil. It was shown that urease was much more sensitive to HM than the other enzymes. There was a obvious negative correlation between the ionic impulsion of HM in soil, the ionic impulsion of HM in canola plants tops and urease activity. It is concluded that the soil urease activity may be a sensitive tool for assessing additive toxic combination effect on soil biochemical parameters.

关键词： multiple heavy metal pollution canola plants soil enzyme ionic impulsion