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High Temperature Mechanical Properties of Ni-Al-Cr Based Alloys for Advanced Die-Materials Applications

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Journal of Materials Science & Technology 2008年第3期24卷 305-308页

作者： w.y.kim H.S.kim y.G.yoo I.D.yeo Advanced Materials R&D Division Korea Institute of Industrial Technology7-47Songdo-dongYeonsu-gu

In this study, we report on advanced Ni3Al based high temperature structural alloys with Zr and B addition in order to apply in the fields of die-casting and high temperature press forming as die materials. Microstructures and mechanical properties of Ni3Al based intermetallic alloys produced by vacuum arc melting were investigated in terms of phase analysis by using a scanning electron microscope （SEM） equipped with an X-ray energy dispersive spectrometer （EDS）, an X-ray diffractometer （XRD） and tensile test. The duplex microstructural feature consisting of γ＇ matrix phase and small intermetallic dispersoids was observed to be distributed over the whole microstructure. The ultimate tensile strength of the present alloy was superior to commercial iron-based and Ni-based die-materials especially in the high temperature region.

关键词： Intermetallic Die material Alloying effect Mechanical property

Microstructure,Elastic Modulus and Tensile Properties of Ti-Nb-O Alloy System

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Journal of Materials Science & Technology 2008年第1期24卷 33-36页

作者： H.S.kim T.y.Ra I.D.yeo H.J.Bang y.G.yoo w.y.kim Advanced Materials R＆D Division Korea Institute of Industrial Technology Incheon 406-800 Korea

In the present study Ti-Nb binary alloy system was chosen because it has excellent biocompatibility as well as reasonable mechanical properties,aiming at understanding oxygen content on microstructural formation, elastic modulus and tensile properties in Ti-Nb alloy *** alloy buttons of 50 mm in diameter were prepared by arc melting on a water-cooled copper hearth under an argon gas atmosphere with a non-consumable tungsten *** button ingots were then heat treated in a vacuum atmosphere at 1273 K for 0.5 h followed by water quenching in a specially designed heat treatment ***,elastic modulus and tensile properties were investigated in order to understand the effect of oxygen content in quenched Ti- Nb alloy *** orthorhombic structuredα″martensite was changed to bcc structuredβ-phase with increasing Nb ***,it was found that oxygen makesβ-phase stable in quenched Ti-Nb alloy *** modulus values were sensitive to phase stability of constituent *** strength increased with increasing oxygen *** will be explained by phase formation and stability behavior.

关键词： Ti-Nb-O alloy Phase stability Elastic modulus Mechanical properties

Superplasticity of fine-grained Mg-10Li alloy prepared by severe plastic deformation and understanding its deformation mechanisms

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Journal of Magnesium and Alloys 2024年第1期12卷 316-331页

作者： H.T.Jeong S.w.Lee w.J.kim Department of Materials Science and Engineering Hongik UniversityMapo-guSangsu-dong 72-1Seoul 121-791Republic of Korea

The superplastic behavior and associated deformation mechanisms of a fine-grained Mg-10.1 Li-0.8Al-0.6Zn alloy(LAZ1011)with a grain size of 3.2μm,primarily composed of the BCCβphase and a small amount of the HCPαphase,were examined in a temperature range of 473 K to 623 *** microstructural refinement of this alloy was achieved by employing high-ratio differential speed *** best superplasticity was achieved at 523 K and at strain rates of 10^(-4)-5×10^(-4)s^(-1),where tensile elongations of 550±600%were *** the heating and holding stage of the tensile samples prior to tensile loading,a significant increase in grain size was observed at temperatures above 573 ***,it was important to consider this effect when analyzing and understanding the superplastic deformation behavior and *** the investigated strain rate range,the superplastic flow at low strain rates was governed by lattice diffusion-controlled grain boundary sliding,while at high strain rates,lattice diffusion-controlled dislocation climb creep was the rate-controlling deformation *** was concluded that solute drag creep is unlikely to *** the late stages of deformation at 523 K,it was observed that grain boundary sliding led to the agglomeration of theαphase,resulting in significant strain *** mechanism maps were constructed forβ-Mg-Li alloys in the form of 2D and 3D formats as a function of strain rate,stress,temperature,and grain size,using the constitutive equations for various deformation mechanisms derived based on the data of the current tests.

关键词： Magnesium-lithium alloy Superplasticity Severe plastic deformation Grain size Grain growth

Effect of Eu3+,Bi3+,and Li+ doping on luminescent property of GdNbO4

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Journal of Rare Earths 2024年第1期42卷 66-75页

作者： S.w.wi y.S.Lee Department of Physics and Integrative Institute of Basic Sciences Soongsil University

we investigated the emission properties of Eu3+-doped GdNbO4-based oxide phosphors,aiming at improving the Eu3+emission by codoping of Bi3+and Li+.Eu3+singly doped,Eu3+and Bi3+doubly doped,and Eu3+,Bi3+,and Li+triply doped GdNbO4were prepared using a high-temperature solid-state reaction *** red-orange emissions from Eu3+in the singly doped samples are significantly improved by the codoping of Bi3+,mainly due to the energy transfer from Bi3+to Eu3+.The additional codoping of Li+is found to increase the Eu3+emission *** improvement might be attributed to the increase in the photoluminescent quantum yield originating from larger grain sizes and better crystallinity.A detailed analysis of the X-ray diffraction pattern and the asymmetric ratio estimated from the photoluminescence spectra show that the local lattice environment around Eu3+in GdNbO4does not change significantly with the codoping of Bi3+and Li+.Our results indicate that Li+doping is a promising way to improve the emission properties of rare-earth ion-doped GdNbO4phosphors.

关键词： Eu 3+ GdNbO 4 Codoping of Li + Photoluminescence Sensitizer Rare earths

Focal Nodular Hyperplasia: A Comprehensive Review with a Particular Focus on Pathogenesis and Complications

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Journal of Clinical and Translational Hepatology 2024年第2期12卷 182-190页

作者： Jaimy Villavicencio kim George y.wu Division of Gastroenterology-Hepatology University of Connecticut Health CenterFarmingtonCTUSA

Focal nodular hyperplasia is a benign tumor of the liver that is often found incidentally with *** purpose of this review is to discuss the pathophysiology,rare complications that can occur due to these lesions,and management options.A literature review was performed on clinical trials and case reports involving focal nodular hyperplasia complications and management of these,as well as the proposed pathogenesis underlying these *** exposure to oral contraceptive pills and endogenous hormones have been thought to play a role in the development of these lesions,this has not been *** recently,they are thought to arise as a consequence of a vascular anomaly causing alterations in the expression of angiopoietin *** are rare,but previous cases have reported associated pain,rupture and compression of nearby structures(hepatic vein,stomach,biliary system).Resection of focal nodular hyperplasia is not usually ***,if there is associated pain with no other identifiable cause or presence of a large or growing lesion with risk of causing a complication,then surgical resection,radiofrequency ablation or arterial embolization should be considered.

关键词： Focal nodular hyperplasia Oral contraceptives Liver lesion

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加利福尼亚湾南部地震和断层作用的机制

世界地震译丛 2013年第5期44卷 24-51页

作者： D.F.Sumy J.B.Gaherty w.y.kim T.Diehl J.A.Collins 李守勇(译) 张黎晓(译) 赵爱平(译) 不详河北省地震局邯郸中心台

地震精定位及其震源机制可以说明断裂的大陆边缘形变的分布和模式。加利福尼亚湾（GoC）内的太平洋一北美（Pa-NA）板块边界由于北部的大陆扩张到南部转变成海底扩张而提供了研究断裂演化和运动学的极好机会。从2005年10月至2006年10月... 详细信息

地震精定位及其震源机制可以说明断裂的大陆边缘形变的分布和模式。加利福尼亚湾（GoC）内的太平洋一北美（Pa-NA）板块边界由于北部的大陆扩张到南部转变成海底扩张而提供了研究断裂演化和运动学的极好机会。从2005年10月至2006年10月，作为科特斯海海底台阵（SCOOBA）试验的一部分，在加利福尼亚湾布设的8个四分量海底地震计的台阵记录了地震活动。通过将这次记录数据与自动记录地震（NARs）-Baja台阵陆上台网的观测资料相结合，我们主要沿勾画出板块边界的北西一南东走向的转换断层观测并定位了约700个地震（A‰2．2～6．6）。对于在长周期（10～20s）频带具有高信噪比的36个地震事件（Mw3．5～6．6），我们通过区域地震波形反演确定了偏矩张量和有关的双力偶震源机制。很多震源机制与沿太平洋一北美转换断层系的右旋走滑断层作用一致，说明这些转换断层主要调节着该海湾内的地震形变。另外，我们在下加利福尼亚上沿右旋北西～南东走向的拉斯比沃拉斯一埃尔阿苏夫雷断层捕捉到可能与该半岛内正在进行的地热活动和火山形变有关的地震群。高分辨率的地震定位与震源机制相结合，提高了我们对加利福尼亚湾南部更大扩张区内地震形变分布的了解。

关键词：加利福尼亚湾走滑断层作用地震精定位震源机制南部海底扩张地震波形反演地震形变

添加蛋氨酸壳聚糖酵母形式的螯合铜对肉仔鸡生产性能的影响

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江西饲料 2007年第1期 32-35页

作者： H.S.Lim I.K.Paik T.I.Sohn w.y.kim 许云贺（译）张莉力（校）不详辽宁医学院畜牧兽医学院

试验研究了添加蛋氨酸螯合铜(Met-Cu)、壳聚糖螯合铜(Chitosan-Cu)、酵母螯合铜(yeast-Cu)对肉仔鸡生产性能、营养物质消化率、血清IGg水平、嗉囊腐蚀程度、肝脏和排泄物中铜(Cu)含量以及肌肉和血清中总胆固醇的水平的影响。240只肉仔鸡... 详细信息

试验研究了添加蛋氨酸螯合铜(Met-Cu)、壳聚糖螯合铜(Chitosan-Cu)、酵母螯合铜(yeast-Cu)对肉仔鸡生产性能、营养物质消化率、血清IGg水平、嗉囊腐蚀程度、肝脏和排泄物中铜(Cu)含量以及肌肉和血清中总胆固醇的水平的影响。240只肉仔鸡(Ross208)平均分配到4个处理组中:对照组、Met-Cu组、Chitosan-Cu组、yeast-Cu组。3个螯合铜试验组日粮铜含量均为100mg/kg。每个处理组中设6个重复,每个重复10只鸡(5只公鸡+5只母鸡)。试验结果表明,螯合铜试验组增重和采食量均高于对照组。Met-Cu组增重显著高于对照组(Pyeast-Cu组采食量显著高于对照组(Pyeast-Cu组。各组间干物质利用率差异显著(P<0.05),螯合铜的试验组干物质利用率显著高于对照组,其中Chitosan-Cu组最高。添加螯合铜提高了嗉囊腐蚀系数,Met-Cu组肝脏铜含量最高。添加螯合铜降低了胸肌和血清中总胆固醇水平,而提高了血清高密度脂蛋白(HDL)水平。试验结果表明,在肉仔鸡日粮中以螯合铜形式添加铜100mg/kg,可以提高增重、采食量和干物质利用率,其中Met-Cu效果最好。

关键词：蛋氨酸螯合铜壳聚糖螯合铜酵母螯合铜肉仔鸡

Developmental impacts and toxicological hallmarks of silver nanoparticles across diverse biological models

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Environmental Science and Ecotechnology 2024年第3期19卷 60-79页

作者： yán wāng yapeng Han De-Xiang Xu Department of Toxicology School of Public Health&Key Laboratory of Environmental Toxicology of Anhui Higher Education InstitutesAnhui Medical UniversityHefei230032China

Silver nanoparticles(AgNPs),revered for their antimicrobial prowess,have become ubiquitous in a range of products,from biomedical equipment to food ***,amidst their rising popularity,concerns loom over their possible detrimental effects on fetal development and subsequent adult *** review delves into the developmental toxicity of AgNPs across diverse models,from aquatic species like zebrafish and catfish to mammalian rodents and in vitro embryonic stem *** focus encompasses the fate of AgNPs in different contexts,elucidating associated hazardous results such as embryotoxicity and adverse pregnancy ***,we scrutinize the enduring adverse impacts on offspring,spanning impaired neurobehavior function,reproductive disorders,cardiopulmonary lesions,and *** hallmarks of developmental harm are identified,encompassing redox imbalances,inflammatory cascades,DNA damage,and mitochondrial ***,we explore potential explanations,linking immunoregulatory dysfunction and disrupted epigenetic modifications to AgNPsinduced developmental *** substantial progress,our understanding of the developmental risks posed by AgNPs remains incomplete,underscoring the urgency of further research in this critical area.

关键词： Silver nanoparticles(AgNPs) Developmental toxicity Maternal exposure Fetal development Redox imbalance Mitochondrial dysfunction

Hyperreflective photonic crystals created by shearing colloidal dispersions at ultrahigh volume fraction

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Microsystems & Nanoengineering 2024年第1期10卷 161-173页

作者： Minji kim Jong Bin kim Shin-Hyun kim Department of Chemical and Biomolecular Engineering Korea Advanced Institute of Science and Technology(KAIST)Daejeon 34141Republic of Korea

Colloidal crystallization serves as one of the most economic and scalable production methods for photonic ***,insufficient optical performance,nonuniformity and low reproducibility remain challenges for advanced high-value *** this study,we optimally formulate a photocurable dispersion of silica particles and apply shear flow to unify the orientation of the colloidal crystals,ensuring high optical performance and *** silica particles experience strong repulsion at ultrahigh volume fractions of 50%but demonstrate low mobility,leading to polycrystalline *** shear flow to the dispersions allows the silica particles to rearrange into larger crystalline domains with a unidirectional orientation along the *** shear-induced structural change produces absolute reflectivity at the stopband as high as 90%and a high transparency of 90%at off-resonant wavelengths with minimal diffusive ***,the strong interparticle repulsion ensures a uniform volume fraction of particles throughout the dispersion,reducing deviations in the optical *** intricately micropattern the photocurable dispersions using ***,the photonic films and patterns can be stacked to form multiple layers,displaying mixed structural colors and multiple reflectance peaks without sacrificing *** superior photonic materials hold promise for various optical applications,including optical components and anticounterfeiting patches.

关键词： properties. dispersion reflectivity