检索结果-南通市图书馆

维普期刊数据库博看期刊

Test research on sticking mechanism during hot rolling of SUS 430 ferritic stainless steel

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2010年第5期17卷 573-578页

作者： jun-xian liu yong-jun Zhang Jing-tao Han School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China

The sticking phenomenon during hot rolling of SUS 430 ferritic stainless steel was investigated by means of a two-disc type high-temperature wear tester. The test results indicate that sticking particles on the surfaces of high chromium steel （HiCr） and high-speed steel （HSS） rolls undergo nucleation, growth, and saturation stages. Grooves on the roll surface generated by grinding provide nucleation sites for sticking particles. The number of sticking particles on the HiCr roll surface is greater than that on the HSS roll surface. The average surface roughnesses （Ra） of HiCr and HSS rolls change from 0.502 and 0.493 μm at the initial stage to 0.837 and 0.530 μm at the saturation stage, respectively. The test further proves that the sticking behavior is strongly dependent on roll materials, and the HSS roll is more benefi- cial to prevent particles sticking compared with the HiCr roll under the same hot-rolling conditions.

关键词： ferritic steel stainless steel hot rolling sticking rolls

ZINDO-SOS Studies on Second-order Nonlinear Optical Properties of Thiophene S,S-Dioxide Chromophores

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2002年第1期18卷 42-46页

作者： liu yong-jun HU Hai-Quan ZHANG Dong-Ju liu Cheng-Bu Institute of Theoretical Chemistry Shandong UniversityJinan 250100P.R.China Department of Chemistry Qufu Normal UniversityQufu 273165P.R.China

The second-order nonlinear optical properties of thiophene S,S -dioxides derivatives were studied by using the ZINDO-SOS method. The computed results show that the thiophene S,S -dioxide derivatives exhibit larger second-order polarizabilities than their thiophene precursors. In order to clarify the origin of the different NLO responses among these chromophores, their electron properties and frontier orbital properties were investigated as well. These thiophene S,S -dioxides derivatives are good candidates for their application in electro-optical device due to their high nonlinearities, good thermal and photo stabilities.

关键词： Second-order optical polarizability Thiophene S,S -dioxides derivatives ZINDO-SOS

窟野河流域水环境中芳烃类有机物的污染状况及风险评价

在线全文

学校读者我要写书评

暂无评论

水生态学杂志 2024年第5期45卷 186-192页

作者：唐慧张爱宁杨壮壮杨璐王柱刘永军西安建筑科技大学环境与市政工程学院西北水资源与环境生态教育部重点实验室陕西西安710055

为了解窟野河流域水体中芳烃类污染物的分布情况及其对环境造成的风险,对流域25个水样品中芳烃类有机物进行检测分析和风险评价。结果表明,窟野河流域水体中共有15种芳烃类有机物被检出,其中,酚类化合物占比93.4%,是主要的污染物;芳烃... 详细信息

为了解窟野河流域水体中芳烃类污染物的分布情况及其对环境造成的风险,对流域25个水样品中芳烃类有机物进行检测分析和风险评价。结果表明,窟野河流域水体中共有15种芳烃类有机物被检出,其中,酚类化合物占比93.4%,是主要的污染物;芳烃类有机物的主要来源是沿流域分布的众多煤化工企业以及道路上机动车排放的尾气;窟野河流域水体中芳烃类有机污染物总浓度为100~5162μg/L,其中,2-4二硝基苯酚的浓度最高,平均值为1601μg/L,检出率为96%,荧蒽和乙苯的浓度最低,平均值仅3μg/L,检出率分别为100%和12%。用反距离权重法对芳烃类有机物的空间分布进行预测,发现污染物浓度沿流域往下逐渐降低,且工业区浓度高于人群聚集区。通过毒性当量法和熵值法对5种芳烃类有机物进行生态风险评价,结果显示5种芳烃类有机物均存在较高的生态风险,各点位不同有机物间的复合污染较高,应引起当地环保部门及相关企业的重视。

关键词：芳烃类有机物分布特征生态风险窟野河流域

维普期刊数据库博看期刊

在线全文

学校读者我要写书评

暂无评论

S100P在肿瘤中的作用研究进展

中国医药生物技术 2024年第4期19卷 347-352页

作者：尹海涵梁爱玲刘勇军广东医科大学医学技术学院东莞523808 广东医科大学基础医学院东莞523808

S100钙结合蛋白P(S100P)属于S100家族的钙结合蛋白,具有典型的EF-手性结构,于1992年首次从胎盘中纯化。研究表明,S100P在肿瘤中表达异常,与多种肿瘤密切相关。它可以参与各种信号通路,如NF-κB、β-catenin和FAK/Src/AKT通路;还可以与... 详细信息

S100钙结合蛋白P(S100P)属于S100家族的钙结合蛋白,具有典型的EF-手性结构,于1992年首次从胎盘中纯化。研究表明,S100P在肿瘤中表达异常,与多种肿瘤密切相关。它可以参与各种信号通路,如NF-κB、β-catenin和FAK/Src/AKT通路;还可以与晚期糖基化终末产物受体、埃兹蛋白、整合素α7等许多其他受体或配体相互作用,从而影响肿瘤的生物学行为。此外,S100P在癌症治疗与肿瘤耐药等方面也发挥着重要作用。本文仅就S100P在肿瘤发生发展、诊断和治疗中的作用进行综述。

关键词： S100P 癌症生物学行为耐药性治疗

A pilot-scale jet bubbling reactor for wet flue gas desulfurization with pyrolusite

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2005年第5期17卷 827-831页

作者： SU Shi-jun ZHU Xiao-fan liu yong-jun JIANG Wen-ju JIN Yan National Engineering Research Center for Flue Gas Desulfurization Department of Environmental Science and Engineering Sichuan University Chengdu 610065 China

MnO2 in pyrolusite can react with SO2 in flue gas and obtain by-product MnSO4· H2O. A pilot scale jet bubbling reactor was applied in this work. Different factors affecting both SO2 absorption efficiency and Mn2^＋ extraction rate have been investigated, these factors include temperature of inlet gas flue, ration of liquid/solid mass flow rate（ L/S）, pyrolusite grade, and SO2 concentration in the inlet flue gas. In the meantime, the procedure of purification of absorption liquid was also discussed. Experiment results indicated that the increase of temperature from 30 to 70 K caused the increase of SO2 absorption efficiency from 81.4% to 91.2%. And when SO2 concentration in the inlet flue gas increased from 500 to 3000 ppm, SO2 absorption efficiency and Mn2^＋ extraction rate decreased from 98.1% to 82.2% and from 82.8% to 61.7%, respectively. The content of MnO2 in pyrolusite had a neglectable effect on SO2, absorption efficiency. Low L/S was good for both removal of SO2 and Mn2^＋ extraction. The absorption liquid was filtrated and purified to remove Si, Mg, Ca, Fe, Al and heavy metals, last product MnSO4· H2O was obtained which quality could reach China GB1622-86, the industry grade standards.

关键词： wet FGD jet bubbling reactor SO2 pyrolusite manganese sulfate

First-Principle Studies on Adsorption of Cu^+ and Hydrated Cu^+ Cations on Clean Si(111) Surface

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2010年第3期26卷 472-478页

作者： CHENG Feng-ming SHENG yong-li LI Meng-hua liu yong-jun YU Zhang-yu liu Cheng-bu School of Chemistry and Chemical Engineering School of Environmental Science and Engineering Shandong University Jinan 250100 P. R. China School of Chemistry and Chemical Engineering University of Jinan Jinan 250022 P. R. China

To study the adsorption behavior of Cu^＋ in aqueous solution on semiconductor surface, the interactions of Cu^＋ and hydrated Cu^＋ cations with the clean Si（111） surface were investigated via hybrid density functional theory（B3LYP） and Moller-Plesset second-order perturbation（MP2） method. The clean Si（111） surface was described with cluster models（Si14H17, Si16H20 and Si22H21） and a four-silicon layer slab under periodic boundary conditions. Calculation results indicate that the bonding nature of adsorption of Cu^＋ on Si surface can be viewed as partial covalent as well as ionic bonding. The binding energies between hydrated Cu^＋ cations and Si（111） surface are large, suggesting a strong interaction between them. The coordination number of Cu^＋（H2O）n on Si（111） surface was found to be 4. As the number of water molecules is larger than 5, water molecules form a hydrogen bond network. In aqueous solution, Cu^＋ cations will safely attach to the clean Si（111） surface.

关键词： Silicon surface Copper Ion-solid interaction Adsorption Density functional calculation

Numerical simulations for radon migration and exhalation behavior during measuring radon exhalation rate with closed-loop method

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2024年第1期35卷 81-95页

作者： Ming Xia yong-jun Ye Shu-Yuan liu School of Resources Environment and Safety Engineering University of South ChinaHengyang 421001China Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy University of South ChinaHengyang 421001China

Accurate measurements of the radon exhalation rate help identify and evaluate radon risk regions in the *** these measurement methods,the closed-loop method is frequently ***,traditional experiments are insufficient or cannot analyze the radon migration and exhalation patterns at the gas–solid interface in the accumulation *** CFD-based technique was applied to predict the radon concentration distribution in a limited space,allowing radon accumulation and exhalation inside the chamber intuitively and *** this study,three radon exhalation rates were defined,and two structural ventilation tubes were designed for the *** consistency of the simulated results with the variation in the radon exhalation rate in a previous experiment or analytical solution was *** effects of the vent tube structure and flow rate on the radon uniformity in the chamber;permeability,insertion depth,and flow rate on the radon exhalation rate and the effective diffusion coefficient on back-diffusion were *** on the results,increasing the inser-tion depth from 1 to 5 cm decreased the effective decay constant by 19.55%,whereas the curve-fitted radon exhalation rate decreased(lower than the initial value)as the deviation from the initial value increased by approximately 7%.Increasing the effective diffusion coefficient from 2.77×10^(-7) to 7.77×10^(-6) m^(2) s^(-1) made the deviation expand from 2.14 to 15.96%.The conclusion is that an increased insertion depth helps reduce leakage in the chamber,subject to notable back-diffusion,and that the closed-loop method is reasonably used for porous media with a low effective diffusion coefficient in view of the back-diffusion *** CFD-based simulation is expected to provide guidance for the optimization of the radon exhalation rate measurement method and,thus,the accurate measurement of the radon exhalation rate.

关键词： Radon exhalation Numerical simulation Accumulation chamber

Activation of β_2-Adrenergic Receptor Induced by Three Catecholamine Agonists:a Docking and Molecular Dynamics Study

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2012年第3期28卷 493-499页

作者： ZHANG Rui DONG Li-hua LING Bao-ping WANG Zhi-guo liu yong-jun Shandong Key Laboratory of Edible Mushroom Technology School of Life SciencesLudong UniversityYantai 264025P.R.China Key Laboratory of Adaptation and Evolution of Plateau Biota Northwest Institute of Plateau BiologyChinese Academy of SciencesXining 810008P.R.China School of Chemistry and Chemical Engineering Shandong UniversityJinan 250100P.R.China

We studied the activation of β2-adrenergic receptor（β2AR） by norepinephrine, epinephrine and isoprote- renol using docking and molecular dynamics（MD） simulation. The simulation was done on the assumption that β2AR was surrounded with explicit water and infinite lipid bilayer membrane at body temperature. So the result should be close to that under the physiological conditions. We calculated the structure of binding sites in β2AR for the three ac- tivators. We also simulated the change of the conformation ofβ2AR in the transmembrane regions（TMs）, in the mo- lecular switches, and in the conserved DRY（Aspartic acid, Arginine and Tyrosine） motif. This study provides detailed information concerning the structure ofβ2AR during activation process.

关键词： β2-Adrenergic receptor(β2AR) G Protein coupled receptor(GPCR) Molecular dynamics Agonist Activa-tion

在线全文

学校读者我要写书评

暂无评论

西方蜜蜂对氟吡呋喃酮和吡虫啉胁迫的响应

环境昆虫学报 2024年第4期46卷 856-865页

作者：陈金郝珈历高晶刘永军王强张丽代平礼吴艳艳中国农业科学院蜜蜂研究所资源昆虫高效养殖与利用全国重点实验室北京100093

因新烟碱类农药对蜜蜂高毒,作为其潜在替代品的氟吡呋喃酮(Flupyradifurone,FPF)受到广泛关注。由于FPF被认为对“蜜蜂安全”,可在作物开花期使用,因而蜜蜂可能存在长期接触FPF的现象。农药胁迫下蜜蜂机体生理指标的响应是解析农药慢性... 详细信息

因新烟碱类农药对蜜蜂高毒,作为其潜在替代品的氟吡呋喃酮(Flupyradifurone,FPF)受到广泛关注。由于FPF被认为对“蜜蜂安全”,可在作物开花期使用,因而蜜蜂可能存在长期接触FPF的现象。农药胁迫下蜜蜂机体生理指标的响应是解析农药慢性毒性的基础。本文比较了FPF和吡虫啉(Imidacloprid,IMI)对蜜蜂存活率、解毒和氧化应激相关酶类以及免疫和凋亡相关基因表达的影响,结果表明,两种农药对哺育蜂的慢性经口毒性相近,均显著降低存活率,导致中肠组织损伤和细胞死亡,并且引起氧化应激、解毒和免疫反应。此外,幸存蜜蜂可能通过抑制过氧化物酶活性和下调细胞凋亡基因表达耐受农药胁迫。以上结果为解析两种农药慢性毒性和抗农药蜂种选育提供一定的理论依据。

关键词：氟吡呋喃酮西方蜜蜂细胞凋亡氧化应激免疫和解毒