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Structure and Deformation of Intermetallic Beryllides

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Journal of Materials Science & Technology 1994年第6期10卷 391-405页

作者： TG.Nieh(lawrence livermore National laboratory, P.O.Box 808, l-350, livermore, ca 94551, USA ) lawrence livermore Natl lab Livermore United States

Intermetallic beryllides are potential light-weight, high-temperature structural materials. In this paper. the processing techniques, microstructure. deformation, and oxidation properties of intermetallic beryllides are described. In addition to nickel beryllides (NiBe). which is treated as a model *** high beryllium-containing refractory beryllides, such as Nb2 Be17. VBe12. are also *** room temperature deformation and high-temperature creep properties of these beryllides are repor4ed. At room temperature. NiBe exhibits certain tensile ductility (~ 1 .3%). but all other beryllides are essentially brittle. Nonetheless, these beryllides become ductile at temperatures above approximately 1000℃. Their creep properties are presented. The creep properties are compared with those of intermetallic aluminides. Also. a comparison is made between the ductile-to-brittle transition behaviour of intermetallic beryllides and that of aluminides. Although beryllides are generally oxidation resistant at high temperatures, some beryllides, e.g., ZrBe13, suffer the pest reaction during oxidation at intermediate tem peratures. The pest mechanisms are proposed

关键词： BeO Res AIME Structure and Deformation of Intermetallic Beryllides MPa

Deformation of metallic glasses with special emphasis in supercooled liquid region

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中国有色金属学会会刊：英文版 2002年第4期12卷 726-733页

作者： T.G.Nieh (lawrence livermore National laboratory, l 350, PO Box 808, livermore, ca 94551, USA) lawrence livermore National laboratory L-350 PO Box 808 Livermore CA 94551 USA

Upon deforming a metallic glass at low temperatures, shear tends to l.calize and this leads to a brittle behavior. However, in the high temperature, and particularly in the supercooled liquid region, homogeneous deformation begins to take place. A bulk amorphous Zr 10Al 5Ti 17.9Cu 14.6Ni alloy was observed to exhibit the Newtonian behavior at low strain rates but becomes non Newtonian at high strain rates in the supercooled liquid region. Structures of the amorphous material, both before and after deformation, were examined using X ray diffraction and high resolution electron microscopy. Results showed the presence of nanocrystallites in the deformed samples. Thus, the non Newtonian behavior is attributable to the concurrent crystallization of the amorphous structure during deformation. A mechanistic model is presented to interpret the observed non Newtonian result. A phenomenological approach is also used to develop the deformation map for bulk metallic glasses in the supercooled liquid region.

关键词：非晶合金金属玻璃超塑性过度冷却液体层

Environmental Occurrence of Selenium in Waters and Related Health Significance

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Biomedical and Environmental Sciences 1997年第2期10卷 292-299页

作者： JANE l. VAlENTINE(School of Public Health, University of calIfornia at los Angeles, los Angeles, ca 90024, USA) School of Public Health University of California at Los Angeles 90024 USA.

Appreciable amounts of selenium in spring and well waters can be found due to geological occurrence. Concentrations of as much as 400 9000 μg/l have been reported in U. S. *** levels are 8 to 180 times the current EPA drinking water standard and approximate dietary exposures of 4900μg in selenosis regions of China. Reviews of health significance of the elevated drinking water exposures to U. S. populations revealed elevated concentrations of selenium in urine and blood. A decrease in glutathione peroxidase activity in such instances was noted. However noticeable symptoms and signs seem absent in studies reviewed. A comparison of intake levels (diet or drinking water) to urinary excretion for residents of China and the U. S. produced a correlation coefficient, r = 0. 82 (P lable

关键词： In Am Environmental Occurrence of Selenium in Waters and Related Health Significance

西南天山榴辉岩相脉体记录的俯冲带多期流体作用

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岩石学报 2025年第1期41卷 183-197页

作者：吕佳阳李继磊王钟瑞马智佩中国科学院地质与地球物理研究所岩石圈演化与环境演变重点实验室北京100029 中国科学院大学地球与行星科学学院北京101408

俯冲带是全球最大的物质循环系统,控制着壳幔相互作用、岛弧岩浆作用、成矿物质聚集和全球元素循环等诸多重要的地质过程。俯冲带流体作为板片向上覆地幔楔进行物质传输的重要媒介,在上述地质过程中扮演着关键角色。基于岛弧火山岩地球... 详细信息

俯冲带是全球最大的物质循环系统,控制着壳幔相互作用、岛弧岩浆作用、成矿物质聚集和全球元素循环等诸多重要的地质过程。俯冲带流体作为板片向上覆地幔楔进行物质传输的重要媒介,在上述地质过程中扮演着关键角色。基于岛弧火山岩地球化学特征、高温高压实验、相平衡模拟,以及高压-超高压变质岩的研究,我们对俯冲带流体基本特征及其地球化学行为已经有了较为深刻的认识,然而,目前对俯冲带流体作用的复杂性,如多期流体作用,还缺少深入的理解。本文对西南天山高压-超高压变质带榴辉岩中一条含石英-绿帘石-铁白云石-硫化物的高压脉开展了详细的岩石学、地球化学研究。脉体中有绿辉石、铁白云石、金红石等特征高压矿物的产出,暗示其代表的流体作用发生于高压条件下。脉体与主岩榴辉岩界线截然,之间无蚀变带/过渡带/交代晕产出,说明主岩榴辉岩与迁移流体之间没有发生显著的水-岩交换反应。脉体矿物(如绿帘石、铁白云石、黄铁矿等)的多期生长特征及其成分差异研究揭示出至少三期流体作用。前两期流体作用均发生于高压条件下,特征如下:(1)两期流体分别以两期矿物组合(Ep^(1)-Dol^(1)-Py^(1)组合以及Ep^(2)-Dol^(2)-Py^(2)组合)为代表,在第二期流体作用下,第一期流体沉淀的矿物(如Dol^(1)等)发生了明显的溶解-再沉淀作用;(2)两期流体性质均以富ca、Si,含C_(2)、S为特征,第一期流体较第二期流体富Fe贫Mg,富Ni贫Co,富轻稀土元素(lREE);(3)两期黄铁矿的δ^(34)S值分别为-8‰和-5‰,暗示这两期流体均主要来源于俯冲沉积物,且第二期流体可能有更多俯冲洋壳或蛇纹岩脱水流体的参与;(4)两期流体作用下,碳酸盐矿物和硫化物显示出耦合共生的特点,暗示C、S在流体作用下可能具有协同演化(如溶解-迁移-沉淀)的关系。第三期流体作用以绿帘石+铁白云石反应生成方解石+绿泥石、绿帘石边部(与黄铁矿相邻处)发生成分改造为特征,流体作用发生在高压岩石折返的退变质阶段,记录了退变质流体的信息。本研究通过榴辉岩高压脉体中多期矿物生长的特征,揭示了俯冲带内多期流体作用,对深入理解俯冲带流体性质、流体来源、以及俯冲带关键挥发分元素的耦合演化信息,具有重要的科学意义。

关键词：西南天山榴辉岩高压脉体俯冲带流体多期流体作用

Neuroimmune actions in the brain and interactions with the effects of alcohol

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Neural Regeneration Research 2021年第9期16卷 1791-1792页

作者： Donna l.Gruol Neuroscience Department The Scripps Research InstituteLa JollaCAUSA

The neuroimmune system of the brain:Early studies(1990’s)on the neurological consequences of human immunodeficiency virus-1(HIV-1)infection in the brain were instrumental in establishing that specific brain cell types can function as an innate immune system within the brain and in that role influence cognitive function(Kaul et al.,2005).

关键词： Neuroimmune actions in the brain and interactions with the effects of alcohol

Sexual selection and hermaphroditic organisms： Testing theory

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Current Zoology 2013年第4期59卷 579-588页

作者： Janet l. lEONARD Joseph M. long Marine laboratory University of California-Santa Cruz Santa Cruz CA 94019 USA

Sexual selection is widespread if not ubiquitous in hermaphroditic organisms. Although many phenomena that have been described as sexual selection in gonochores, （e.g. harem polygamy, multiple mating, elaborate courtship, even secondary sexual characters） can be found in some hermaphrodites, what is more interesting is the ways in which sexual selection in her- maphrodites may differ from dioecious taxa. In hermaphrodites, an individual＇s mating success includes its success from both sexual roles. Secondly, in many simultaneously hermaphroditic taxa there is strong evidence of sexual selection and yet the ope- rational sex ratio is 1：1, by definition. Many simultaneous hermaphrodites have elaborate courtship and genital anatomy, suggest- ing sexual selection plays an important role in reproductive success. Sperm competition and cryptic female choice mean that the number of mates acquired is not necessarily a predictor of reproductive success. Even in simultaneous hermaphrodites with re- ciprocal mating, variance in reproductive success through the male role and through the female role may differ in a population. Moreover hermaphrodites may choose to emphasize one sexual role over the other. Data suggest that the preferred role varies in hermaphrodites, which creates an opportunity to test fundamental predictions and assumptions of sexual selection theory. Hermaphrodites may vary their emphasis on one sexual role over the other either developmentally or behaviorally in response to environmental or social parameters. How they use this capability in acquiring more or higher quality mates still requires study

关键词： Sexual selection Hermaphrodites Mate choice Reproductive success

Differential Evolution of High-Pressure and Ultrahigh-Pressure Metapelites from Habutengsu, Chinese Western Tianshan: Phase Equilibria Modelling and ^(40)Ar/^(39)Ar Geochronology

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Acta Geologica Sinica(English Edition) 2016年第2期90卷 628-640页

作者： lü Zeng ZHANG lifei The Key laboratory of Orogenic Belts and Crustal Evolution School of Earth and Space SciencesPeking University

Metapelite is one of the predominant rock types in the high-pressure–ultrahigh-pressure（HP–UHP） metamorphic belt of western Tianshan, NW China; however, the spatial and temporal variations of this belt during metamorphism are poorly understood. In this study, we present comparative petrological studies and 40^Ar/39 ^Ar geochronology of HP and UHP pelitic schist exposed along the Habutengsu valley. The schist mainly comprises quartz, white mica, garnet, albite and bluish amphibole. In the Mn O–Na2O–ca O–K2O–Fe O–Mg O–Al2O3–Si O2–H2O（Mn NCKFMASH） system, P–T pseudosections were constructed using THERMOcalC 333 for two representative pelitic schists. The results demonstrate that there was a break in the peak metamorphic pressures in the Habutengsu area. The northern schist has experienced UHP metamorphism, consistent with the presence of coesite in the same section, while the southern one formed at lower pressures that stabilized the quartz. This result supports the previous finding of a metamorphic gradient through the HP–UHP metamorphic belt of the Chinese western Tianshan by the authors. Additionally, phengite in the northern schist was modelled as having a Si content of 3.55–3.70（a.p.f.u.） at the peak stage, a value much higher than that of oriented matrix phengite（Si content 3.32–3.38 a.p.f.u.）. This indicates that the phengite flakes in the UHP schist were subjected to recrystallization during exhumation, which is consistent with the presence of phengite aggregates surrounding garnet porphyroblast. The 40^Ar/39^ Ar age spectra of white mica（dominantly phengite） from the two schists exhibit similar plateau ages of ca. 315 Ma, which is interpreted as the timing of a tectonometamorphic event that occurred during the exhumation of the HP–UHP metamorphic belt of the Chinese western Tianshan.

关键词： pelitic schist HP–UHP metamorphism P–T pseudosection 40^Ar/39^Ar geochronology Chinese western Tianshan

The effects of indigenous prescribed fire on riparian vegetation in central.california

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Ecological Processes 2013年第1期2卷 245-253页

作者： Don l Hankins Department of Geography and Planning California State University-ChicoChicoCAUSA

Introduction:Fire has a long history,but little documented role,as a process in riparian *** millennia california Indians have applied fire to riparian ecosystems for a variety of purposes,but the effects of such fires on riparian vegetation are poorly known outside of traditional knowledge structures of indigenous ***:This study involved the seasonal appl.cation of fire based on traditional ecological knowledge versus alternate burn methods to assess fire effects on riparian vegetation in central ***:While the annual variation amongst treatments was not significant,the results of this study suggest that fall burns support higher overall richness and native species richness;spring burns yield a decrease in overall richness,but an increase in native species richness;and summer burns contribute to an initial decline in overall and native species *** evenness indices of treatments increase most with spring and summer ***:These findings are key to understanding the seasonal role of fire in managing native species in areas prone to non-native or other invasive *** research demonstrates the appl.cation of traditional ecological knowledge to facilitate an understanding of how prescribed fire could aid in the management and conservation of riparian ecosystems.

关键词： Riparian california Indian Fire Indigenous Traditional ecological knowledge

Metallurgical properties of caO–SiO_(2)–Al_(2)O_(3)–4.6wt%MgO–Fe_(2)O_(3)slag system pertaining to spent automotive catalyst smelting

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International Journal of Minerals,Metallurgy and Materials 2023年第5期30卷 886-896页

作者： Ruili Zheng Jianfang lü Weifeng Song Mudan liu Huashan li Yong liu Xianjin lü Zhiyuan Ma School of Environmental Science and Engineering Guangdong University of TechnologyGuangzhou 510006China Institute of Resources Utilization and Rare Earth Development Guangdong Academy of SciencesGuangzhou 510650China State Key laboratory of Rare Metals Separation and Comprehensive Utilization Guangzhou 510650China Guangdong Key laboratory of Mineral Resources Development and Comprehensive Utilization Guangzhou 510650China

The metallurgical properties of the caO–SiO_(2)–Al_(2)O_(3)–4.6wt%Mg O–Fe_(2)O_(3)slag system,formed by the co-treatment process of spent automotive catalyst(SAC)and copper-bearing electroplating sludge(CBES),were studied systematically in this *** slag structure,melting temperature,and viscous characteristics were investigated by Fourier transform infrared(FTIR)spectroscopy,Raman spectroscopy,Fact Sage calculation,and viscosity *** results show that the increase of Fe_(2)O_(3)content(3.8wt%–16.6wt%),the mass ratio of caO/SiO_(2)(m(caO)/m(SiO_(2)),0.5–1.3),and the mass ratio of SiO_(2)/Al_(2)O_(3)(m(SiO_(2))/m(Al_(2)O_(3)),1.0–5.0)can promote the depolymerization of sil.cate network,and the presence of a large amount of Fe_(2)O_(3)in form of tetrahedral and octahedral units ensures the charge compensation of Al^(3+)ions and makes Al_(2)O_(3)only behave as an acid *** calculation and viscosity measurements show that with the increase of Fe_(2)O_(3)content,m(ca O)/m(SiO_(2)),and m(SiO_(2))/m(Al_(2)O_(3)),the depolymerization of sil.cate network structure and low-melting-point phase transformation first occur within the slag,leading to the decrease in melting point and viscosity of the slag,while further increase causes the formation of high-melting-point phase and a resultant re-increase in viscosity and melting *** on experimental analysis,the preferred slag composition with low polymerization degree,viscosity,and melting point is as follows:Fe_(2)O_(3)content of 10.2wt%–13.4wt%,m(caO)/m(SiO_(2))of 0.7–0.9 and m(SiO_(2))/m(Al_(2)O_(3))of 3.0–*** work provides a theoretical support for slag design in co-smelting process of SAC and CBES.

关键词： spent automotive catalyst co-treatment slag system slag structure melting temperature phase transformation viscosity