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Ti_(3)SiC_(2)陶瓷室温压缩变形行为的尺寸效应 被引量:1
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作者 刘亚妮 彭升远 +1 位作者 薛建明 张海斌 《材料热处理学报》 CAS CSCD 北大核心 2021年第11期147-154,共8页
通过微柱压缩法研究了Ti_(3)SiC_(2)微柱在室温下的变形行为与其尺寸的关系。结果表明:Ti_(3)SiC_(2)微压缩初期的应力应变曲线为弹性加载,随后曲线斜率逐渐变小直至断裂,屈服强度和杨氏模量随试样尺寸的减小而增大。利用扫描电镜及透... 通过微柱压缩法研究了Ti_(3)SiC_(2)微柱在室温下的变形行为与其尺寸的关系。结果表明:Ti_(3)SiC_(2)微压缩初期的应力应变曲线为弹性加载,随后曲线斜率逐渐变小直至断裂,屈服强度和杨氏模量随试样尺寸的减小而增大。利用扫描电镜及透射电镜对微柱的变形机制进行了研究,发现基底滑移是Ti_(3)SiC_(2)微柱室温下唯一的滑移体系,基面位错滑移到自由表面最终形成边缘位错墙。结合位错匮乏机制和单臂位错源模型,关于Ti_(3)SiC_(2)微柱微压缩的尺寸效应可以解释为由于在小尺度范围内位错的密度很小,使得位错形核困难,因此需要更高的应力来激活新的位错源;但随着微柱尺寸增大,留在试样内部的位错通过相互反应生成位错源,此时位错运动应力成为变形行为的主导机制。 展开更多
关键词 Ti_(3)SiC_(2)陶瓷 微柱压缩 尺寸效应
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二次再热超超临界汽轮发电机组轴系动力响应特性研究 被引量:3
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作者 王文飚 薛建明 +3 位作者 谭锐 何新荣 董月红 郭瑞 《汽轮机技术》 北大核心 2020年第5期363-366,共4页
以某型1000MW二次再热超超临界汽轮发电机组轴系为对象,建立了轴系有限元求解模型,深入研究了轴系的固有频率分布、同相及反相分量后的响应等动力特性。结果表明,轴系超高压及高压转子模态耦合效应明显;轴系中各转子在不平衡力的作用下... 以某型1000MW二次再热超超临界汽轮发电机组轴系为对象,建立了轴系有限元求解模型,深入研究了轴系的固有频率分布、同相及反相分量后的响应等动力特性。结果表明,轴系超高压及高压转子模态耦合效应明显;轴系中各转子在不平衡力的作用下前瓦的振幅响应要大于后瓦,后侧的转子影响前侧的转子;相对于对称不平衡质量分布,反对称质量分布引起的响应特性更为复杂,它会同时激发出本转子和邻近前一个转子的一阶振型;1号瓦截面处的振动响应易受到后面各转子不平衡量的影响,尤其是反对称不平衡量的影响,低压转子的反对称不平衡也会引起1号瓦在2200r/min处出现峰值;在工作转速下时,承载转子的两侧各瓦从相位来看能体现出对应的振型。 展开更多
关键词 二次再热超超临界 动力特性 有限元模型
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Uptake and translocation of organic pollutants in plants:A review 被引量:10
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作者 ZHANG Cheng FENG Yao +3 位作者 LIU Yuan-wang CHANG Hui-qing LI Zhao-jun xue jian-ming 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2017年第8期1659-1668,共10页
Organic pollutants, such as polychlorinated dJbenzo-p-dioxins and polychlofinated dibenzofurans (PCDD/Fs), polychlodnated biphenyls (PCBs), antibiotics, herbicides, and bisphenol A (BPA), are commonly found in a... Organic pollutants, such as polychlorinated dJbenzo-p-dioxins and polychlofinated dibenzofurans (PCDD/Fs), polychlodnated biphenyls (PCBs), antibiotics, herbicides, and bisphenol A (BPA), are commonly found in agricultural environments. They are released into the environment as a result of their use for human health purposes and farm management activities, and are often discharged as waste-water effluents. Most of these organic pollutants are taken up by plants through roots and leaves, and when they enter the tissue, they cause serious damage to the plants. Although the toxicity of organic pollutants to plants, especially to plant cells, has been intensively studied, a systematic review of these studies is lacking. Here we review researches on the toxicity of organic pollutants, their uptake, and translocation in plants. Our objective is to assemble existing knowledge concerning the interaction of organic pollutants with plants, which should be useful for the development of plant-based systems for removing pollutants from aquatic and agricultural environments. 展开更多
关键词 organic pollutants PLANT UPTAKE CYTOTOXICITY
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Prediction model for mercury transfer from soil to corn grain and its cross-species extrapolation 被引量:1
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作者 HU Hai-yan LI Zhao-jun +4 位作者 FENG Yao LIU Yuan-wang xue jian-ming Murray Davis LIANG Yong-chao 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2016年第10期2393-2402,共10页
In this study the transfer characteristics of mercury(Hg) from a wide range of Chinese soils to corn grain(cultivar Zhengdan 958) were investigated. Prediction models were developed for determining the Hg bioconce... In this study the transfer characteristics of mercury(Hg) from a wide range of Chinese soils to corn grain(cultivar Zhengdan 958) were investigated. Prediction models were developed for determining the Hg bioconcentration factor(BCF) of Zhengdan 958 from soil, including the soil properties, such as p H, organic matter(OM) concentration, cation exchange capacity(CEC), total nitrogen concentration(TN), total phosphorus concentration(TP), total potassium concentration(TK), and total Hg concentration(THg), using multiple stepwise regression analysis. These prediction models were applied to other non-model corn cultivars using a cross-species extrapolation approach. The results indicated that the soil p H was the most important factor associated with the transfer of Hg from soil to corn grain. Hg bioaccumulation in corn grain increased with the decreasing p H. No significant differences were found between two prediction models derived from different rates of Hg applied to the soil as HgCl2. The prediction models established in this study can be applied to other non-model corn cultivars and are useful for predicting Hg bioconcentration in corn grain and assessing the ecological risk of Hg in different soils. 展开更多
关键词 soils corn grain bioconcentration factor(BCF) prediction model Hg
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Study of calf thymus DNA irradiated in vitro with MeV fluorine ions
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作者 MIAO Qi LAI Jiang-Nan +4 位作者 xue jian-ming QIN Huai-Li WANG Wei-Dong QIN Guang-Yong WANG Yu-Gang 《Nuclear Science and Techniques》 SCIE CAS CSCD 2006年第5期272-275,共4页
A study of the fragments of DNA irradiated with MeV ions is important for the understanding of the DNA damage mechanism and the subsequent biological effects (induced by heavy ions). In this experiment, the products o... A study of the fragments of DNA irradiated with MeV ions is important for the understanding of the DNA damage mechanism and the subsequent biological effects (induced by heavy ions). In this experiment, the products of calf thymus DNA (CT DNA) irradiated with MeV fluorine ions were analyzed using agarose gel electrophoresis, modified time-of-flight mass spectrometer (MALDI-TOF), and high-performance liquid chromatography (HPLC). The results showed that the molecular mass of the fragments were concentrated around 831 bp with agarose gel elec- trophoresis, there was no observable product in the range of 1,000 ? 30,000 (m/q) using MALDI-TOF, and small bio- molecules were separated from the products. The results of this study indicated that the strand breaks of calf thymus DNA induced by MeV fluorine ions were nonrandom. 展开更多
关键词 胸腺DNA 氟离子 体外辐照 DNA损伤机制
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Fluorine ion transmission through thin biological samples
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作者 xue jian-ming Wang Yu-Gang +3 位作者 Lu Xi-Ting Yan Sha Chen Jiang Zhao Wei-Jiang (Institute of Heavy Ion Physics, Peking Univcrsity, Beijing 100871) 《Nuclear Science and Techniques》 SCIE CAS CSCD 1998年第4期218-220,共3页
F2+ beam with 3 MeV is used to irradiate thin biological samples (onion innersurface membrane and kidney beau coat) in the transmission measurement, its current densityis 400-800 nA/cm2. Results show that the onion sa... F2+ beam with 3 MeV is used to irradiate thin biological samples (onion innersurface membrane and kidney beau coat) in the transmission measurement, its current densityis 400-800 nA/cm2. Results show that the onion samples can be broken up quickly under ionirradiating; as to kidney beau samples, about 60% of tile implanted ions penetrate the samples,most of them lose part of their energy, fewer ions are found to be able to transmit throughthe sample without energy loss. SEM experiments are carried out to study sample’s damageinduced by tile ions irradiation. 展开更多
关键词 氟离子 离子移植 生物样品 传输测量
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燃煤电站炭基催化法脱硫脱硝工艺参数分析 被引量:4
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作者 程文煜 邢德山 +3 位作者 薛建明 樊腾飞 谷建功 何道远 《环境工程》 CAS CSCD 北大核心 2019年第4期112-116,11,共6页
在自主设计建设的炭基催化剂脱硫脱硝试验平台上,通过单一变量试验,分别研究了ρ(SO_2)、φ(O_2)、φ(水蒸气)、床层温度、空速、ρ(NO)、氨氮比等工艺参数对炭基催化剂脱硫脱硝性能的影响,分析得到了适合燃煤电站炭基催化法脱硫脱硝技... 在自主设计建设的炭基催化剂脱硫脱硝试验平台上,通过单一变量试验,分别研究了ρ(SO_2)、φ(O_2)、φ(水蒸气)、床层温度、空速、ρ(NO)、氨氮比等工艺参数对炭基催化剂脱硫脱硝性能的影响,分析得到了适合燃煤电站炭基催化法脱硫脱硝技术的工艺参数。较优的脱硫工艺参数为:ρ(O_2)为3%~4%,φ(水蒸气)为12%,床层温度为80~120℃,空速为400~2200 h-1,此时脱硫效率达到98%以上;较优的脱硝工艺参数为:φ(O_2)为3%~4%,φ(水蒸气)为5%,床层温度为110~130℃,空速为1000 h-1,氨氮比>1,此时脱硝效率达到70%以上;在电厂烟气的温度及φ(O_2)条件下,炭基催化剂有较高的脱硫脱硝效率,为其在电力行业的应用提供参考。 展开更多
关键词 炭基催化剂 脱硫 脱硝 工艺参数 燃煤电站
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