检索结果-南通市图书馆

Grade-4 commercially pure titanium with ultrahigh strength achieved by twinning-induced grain refinement through cryogenic deformation

引用

Journal of Materials Science & Technology 2021年第7期66卷 193-201页

作者： Seong-Woo Choi jae Sukjeong Jong Woo Won jae Keun Hong Yoon Suk Choi Titanium Department.Korea Institute of Materials Science Changwon51508Republic of Korea School of Materials Science and Engineering Pusan National UniversityPusan.46241Republic of Korea Materials and Manufacturing Development Team Doosan Heavy Industries and ConstructionChangwon51711Republic of Korea

The yield strength of commercially pure(CP) Ti of ASTM grade 4, the strongest among all the CP-Ti grades, is too low for structural applications that require high-strength materials. Here, we demonstrate the strengthening of grade-4 CP Ti by cryogenic-temperature rolling(CTR), which enables deformation twinning in grade-4 CP Ti to achieve twinning-induced grain refinement. CTR activated {11.22} twinning and {10.12} twinning, which are the most common twinning systems in pure Ti, whereas room-temperature rolling(RTR) did not activate any twinning system. CTR with imposing an area reduction of just 30% significantly increased the yield strength of the CP Ti to 946 MPa, which is not achievable through typical processes performed at or above room temperature and is comparable to that of commercial Ti-6 Al-4 V. The significant increase in strength was due to microstructural strengthening caused by twinning-induced grain refinement, combined with dislocation accumulation. In contrast to RTR, CTR greatly increased the stress concentration at grain boundaries(GBs), which caused the unusual activation of twinning in the grade-4 CP Ti by facilitating twin nucleation at GBs. The stress concentration increased because CTR activated the slip to a lesser extent compared to RTR, thereby reducing the strain compatibility between neighboring grains. These results will contribute to development of ultrahigh-strength CP Ti and may thereby extend its use to structural applications that require high-strength materials.

关键词： Titanium Twinning Cryogenic deformation Grain refinement Tensile properties

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effect of CaF2 content in refining slag on formation behavior of spinel inclusion in Ni-Cr-V-alloyed special steel

引用

Journal of Iron and Steel Research International 2018年第2期25卷 157-163页

作者： jae-hong Shin Joo-hyun Park Department of Materials Engineering Hanyang UniversityAnsan 426-791 Korea

The influence of CaF2 content on the formation behavior of spinel inclusions in the Ni-Cr-V-alloyed special steel was presented. The spinel was not formed at CaF2 content lower than 10 wt%. However, it was formed at early stage when the CaF2 content was greater than 30 wt%, followed by a modification to the aluminosilicate-type inclusions. Because the slag was saturated by MgO, the activity of MgO was unity irrespective of CaF2 content in the slag. Thus, Mg was transferred from slag to metal phase. Mg transferred to molten steel reacted with Al2O3-rich inclusions to form ***2O3 spinel. However, the spinel inclusion was modified to aluminosilicate-type inclusions by the reaction with Si and Ca transferred from slag to molten steel about 2-3 h later.

关键词： Spinel inclusion Refining slag CaF2 content Ni-Cr-V-alloyed special steel

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

k-Nearest Neighbor Query Processing Algorithms for a Query Region in Road Networks

引用

Journal of Computer Science & Technology 2013年第4期28卷 585-596页

作者： Hyeong-Il Kim jae-Woo Chang Department of Computer Engineering Chonbuk National University Cloud Open R&D Center Chonbuk National University

Recent development of wireless communication technologies and the popularity of smart phones .are making location-based services （LBS） popular. However, requesting queries to LBS servers with users＇ exact locations may threat the privacy of users. Therefore, there have been many researches on generating a cloaked query region for user privacy protection. Consequently, an efficient query processing algorithm for a query region is required. So, in this paper, we propose k-nearest neighbor query （k-NN） processing algorithms for a query region in road networks. To efficiently retrieve k-NN points of interest （POIs）, we make use of the Island index. We also propose a method that generates an adaptive Island index to improve the query processing performance and storage usage. Finally, we show by our performance analysis that our k-NN query processing algorithms outperform the existing k-Range Nearest Neighbor （kRNN） algorithm in terms of network expansion cost and query processing time.

关键词： island index k-nearest neighbor query processing scheme locatiombased service road network

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Variations in dynamic recrystallization behavior and mechanical properties of AZ31 alloy with extrusion temperature

引用

镁合金学报(英文) 2023年第7期11卷 2351-2365页

作者： jae Won Cha Sung Hyuk Park School of Materials Science and Engineering Kyungpook National UniversityDaegu 41566Republic of Korea

This study investigates the effects of extrusion temperature on the dynamic recrystallization(DRX)behavior of a Mg-3Al-1Zn-0.3Mn(AZ31,wt%)alloy during hot extrusion and on the microstructural characteristics and mechanical properties of materials extruded at 350 and 450℃.An increase in the extrusion temperature causes a decrease in the amount of strain energy accumulated in the material during extrusion,because of promoted activation of pyramidalslip and dynamic *** reduced strain energy weakens the DRX behavior during extrusion,which eventually results in a decrease in the area fraction of recrystallized grains of the extruded *** material extruded at 450℃has coarser grains and a stronger basal fiber texture than that extruded at 350℃.As the extrusion temperature increases from 350 to 450℃,the tensile yield strength(TYS)of the extruded material increases from 191.8 to 201.5 MPa,whereas its compressive yield strength(CYS)decreases from 122.5 to 111.0 MPa;consequently,its tension-compression yield stress ratio(CYS/TYS)decreases from 0.64 to *** increase in the TYS is attributed mainly to the stronger texture hardening and strain hardening effects of the extruded material,and the decrease in the CYS is attributed to the reduced twinning stress resulting from grain coarsening and texture *** microstructural and textural evolutions of the materials during extrusion and the deformation and hardening mechanisms of the extruded materials are discussed in detail.

关键词： Mg-Al-Zn alloy Extrusion Dynamic recrystallization Microstructure Yield asymmetry

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Genomic organization and transcriptional modulation in response to endocrine disrupting chemicals of three vitellogenin genes in the self-fertilizing fish Kryptolebias marmoratus

引用

Journal of Environmental Sciences 2016年第4期28卷 187-195页

作者： Bo-Mi Kim Min Chul Lee Hye-Min Kang jae-Sung Rhee jae-Seong Lee Department of Biological Science College of ScienceSungkyunkwan University Department of Marine Science College of Natural SciencesIncheon National University

Vitellogenin（Vtg）is the precursor of egg yolk proteins,and its expression has been used as a reliable biomarker for estrogenic contamination in the aquatic *** examine the biomarker potential of the self-fertilizing killifish Kryptolebias marmoratus Vtgs（Km-Vtgs）,full genomic DNAs of Km-Vtgs-Aa,Km-Vtgs-Ab,and Km-Vtgs-C were cloned,sequenced,and *** Vtg genes in *** are tandemly placed in a550 kb section of the same *** silico analysis of promoter regions revealed that both the Km-Vtgs-Aa and Km-Vtgs-Ab genes had an estrogen response element（ERE）,but the Km-Vtgs-C gene did ***,all three Km-Vtgs genes had several ERE-half sites in their promoter *** analysis demonstrated that the three deduced amino acid residues were highly conserved with conventional Vtgs protein,forming distinctive clades within teleost *** tissue showed the highest expression of Km-Vtg transcripts in all tested tissues（brain/pituitary,eye,gonad,intestine,skin,and muscle）in response to endocrine disrupting chemical（EDC）-exposed ***-Vtg transcripts were significantly increased in response to 17β-estradiol（E2）,tamoxifen（TMX）,4-n-nonylphenol（NP）,bisphenol A（BPA）,and octylphenol（OP）over 24 hr *** Km-Vtg-A gene was highly expressed compared to the control in response to NP and ***-induced modulatory patterns of Km-Vtg gene expression were different depending on tissue,gender,and isoforms.

关键词： Kryptolebias marmoratus Vitellogenin Endocrine disrupting chemical

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Reduced interface energy loss in non-fullerene organic solar cells using room temperature-synthesized SnO2 quantum dots

引用

Journal of Materials Science & Technology 2020年第17期52卷 12-19页

作者： In Su Jin Minwoo Park jae Woong Jung Department of Advanced Materials Engineering for Information&Electronics Kyung Hee University1732 Deogyeong-daeroGiheung-guYongin-siGyeonggi-do 446-701Republic of Korea Department of Chemical and Biological Engineering Sookmyung Women's UniversitySeoul 04310Republic of Korea

We herein report the room temperature synthesis of colloidal SnO2 quantum dots and their application in non-fullerene organic solar cells as an excellent electron transport *** thiourea-assisted hydrolysis at room temperature affords the nanocrystalline SnO2 quantum dots with a diameter of 3-4 *** utilization of the SnO2 quantum dots as an electron transporting layer effectively reduces the interfacial trap density and charge recombination in the solar cell devices,leading to not only the reduced energy loss but also excellent photocurrent *** optimized organic solar cells employing SnO2 quantum dots with polyethylenimine ethoxylated achieves power conversion efficiencies up to 12.023%with a VOC,a JSC,and a FF of 0.89 V,18.89 mA cm^–2,and *** work suggest that the SnO2 quantum dot is a promising electron transporting material to construct efficient organic solar cells for practical *** work also demonstrates the key strategy for thiourea-assisted hydrolysis to synthesize fine and nanocrystalline SnO2 quantum dots.

关键词： Energy loss Organic solar cells Interface SnO2 Quantum dots

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Simultaneously enhanced efficiency and ambient stability of inorganic perovskite solar cells by employing tetramethylammonium chloride additive in CsPbI2Br

引用

Journal of Materials Science & Technology 2022年第7期102卷 224-231页

作者： In Su Jin Bhaskar Parida jae Woong Jung Department of Advanced Materials Engineering for Information and Electronics Kyung Hee University1732 Deogyeong-daeroGiheung-guYongin-siGyeonggi-do 446-701Republic of Korea Integrated Education Institute for Frontier Materials(BK21 Four) Kyung Hee University1732 Deogyeong-daeroGiheung-guYongin-siGyeonggi-do 446-701Republic of Korea

Although all-inorganic perovskites possess suitable bandgap and thermal stability for photovoltaic ap-plications,the unstable film morphologies,and poor moisture stabilities lag behind the organic-inorganic hybrid ***,we demonstrate that high qualityα-CsPbI_(2 ) Br films with improved phase sta-bility,high crystallinity,and pinhole-free film morphology was achieved by employing tetramethylammo-nium chloride(TMACl)as an *** a result,the TMACl-added CsPbI_(2) Br films exhibited high power conversion efficiency of 14.12%with an open-circuit voltage of 1.19 V,a short-circuit current density of 15.08 mA/cm^(2),and a fill factor of *** importantly,the TMACl addition imparts hydrophobicity to the film surface of CsPbI_(2) Br,which delivered excellent stability up to 30 days in the ambient condition and thermal stability at 85℃ for 156 h,***,the TMACl-added device also exhibited excellent PCE of 27.16%under indoor light source(1000 lux),which presents a promising approach for designing stable but high performance all-inorganic perovskite solar cells.

关键词： Inorganic perovskite solar cells CsPbI2Br Additive Tetramethylammonium chloride Efficiency

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Infrared-harvesting colloidal quantum dot inks for efficient photovoltaics: Impact of surface chemistry and device engineering

引用

Journal of Materials Science & Technology 2023年第16期147卷 224-240页

作者： Younghoon Kim Min-jae Choi Jongmin Choi Department of Chemistry Kookmin UniversitySeoul02707Republic of Korea Department of Chemical and Biochemical Engineering Dongguk UniversitySeoul04620Republic of Korea Department of Energy Science and Engineering Daegu Gyeongbuk Institute of Science and Technology(DGIST)Daegu42988Republic of Korea

Colloidal quantum dots(CQDs)are promising semiconducting materials,which can be used as a photoactive layer in various optoelectronic applications,because of their size-tunable bandgap energy,solution processability,and excellent optical and optoelectronic *** particular,these features have generated great interest in the development of CQD solar cells and led to a rapid increase in their power conversion *** improvements were enabled by many innovative approaches in terms of CQD’s surface chemistry and device architecture *** this review,a critical overview of the research progress in CQD solar cells is presented with a focus on the strategies adopted for achieving record efficiency in CQD solar *** strategies include the use of organic/inorganic surface ligands,pre-and post-treatment of CQDs,and solid-state/solution-phase ligand ***,we provide an understanding of the research history to inspire the rational design of next-generation CQD optoelectronic devices,such as solar cells,light-emitting diodes,and *** research on the development of infrared CQD solar cells as complementary platforms to other solar cell technologies is also critically discussed to provide another perspective on CQD technologies.

关键词： Quantum dot Lead sulfide Ligand exchange Colloidal ink Infrared light Solar cell

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Comparison of mesophilic and thermophilic anaerobic digestions of thermal hydrolysis pretreated swine manure: Process performance,microbial communities and energy balance

引用

Journal of Environmental Sciences 2023年第4期126卷 222-233页

作者： Xiaohui Liu Changmin Lee jae Young Kim Department of Civil and Environmental Engineering Seoul National UniversitySeoul 08826Korea

Anaerobic digestion (AD) of swine manure (SM) commonly shows low biogas output and unsatisfactory economic performance. In this study, thermophilic AD (TAD, 50±1℃) was combined with thermal hydrolysis pretreatment (THP, 170℃/10 bar), to investigate its potential for maximizing biogas yield, securing successful digestion and microbial diversity, as well as improving energy balance. Four lab-scale continuously stirred tank reactors were operated for 300 days and compared with each other, i.e., reactor 1 (raw SM fed in mesophilic AD:RSM-MAD), reactor 2 (THP-treated SM fed in MAD:TSM-MAD), reactor 3 (RSM-TAD),and reactor 4 (TSM-TAD). The results showed that THP was efficient to increase methane production of SM, TSM-TAD mode led to the highest methane yield (129.8±40.5 mL-CH_(4)/gVS/day) among the tests (p 700 mg/L) or volatile fatty acids (> 6000 mg/L) accumulation compared with MAD in start-up phase, TSM-TAD treatment mode behaved a sustainable digestion process in a long-term operation. For TSM-TAD scenario, higher Shannon–Weaver (3.873) and lower Simpson index (0.061) indicated this mode ensured and enlarged the diversity of bacteria communities. Phylum Bathyarchaeota was dominant (59.3%-90.0%) in archaea community,followed by Euryarchaeota in the four reactors. RSM-MAD treatment mode achieved the highest energy output (4.65 GJ/day), TSM-TAD was less effective (-17.38 GJ/day) due to increased energy demands. Thus improving the energetic efficiency of THP units is recommended for the development of TSM-TAD treatment mode.

关键词： Thermal hydrolysis pretreatment Digestion temperature Process performances Microbial communities Energy balance

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Sodium nitrite-derived nitric oxide protects rat testes against ischemia/reperfusion injury

引用

Asian Journal of Andrology 2019年第1期21卷 92-97页

作者： jae Won Lee Dong-Hun Lee jae Keun Park Jin Soo Han Center for Convergence Bioceramic Materials Korea Institute of Ceramic Engineering and TechnologyChungcheongbuk-do 28160Korea Department of Awan Diseases Laboratory College of Veterinary MedicineKonkuk UniversitySeoul 05029Korea Viral Pathogenesls Section Laboratory of Infectious DiseasesNational Institute of Allergy and infectious DiseasesNational institutes of HealthBethesdaMD 20892USA The institute for the 3Rs & Department of Laboratory Animal Medicine College of Veterinary Medicine and Veterinary Science Research instituteKonkuk UniversitySeoul 05029Korea.

Testicular torsion,a common urologic emergency,is primarily caused by ischemia/reperfusion (I/R)injury of the *** oxide (NO)-derived from nitrite (NO2-)has been reported to have prominent therapeutic effects on I/R injury in the heart,liver,and brain;however,its effects on testicular I/R injury have not been *** study,therefore,investigated whether NO from NO2^-is beneficial in a rat model of testicular I/R injury which eventually results in impaired *** Sprague-Dawley rats were assigned to the following seven groups:group A,sham-operated control group;Group B,I/R with no treatment;Groups C, D,and E,I/R followed by treatment with three different doses of NO2^-;Group F,I/R followed by administration of NO2-and NO scavenger (2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-l-oxyl-3-oxide potassium salt [C-PTIO]);and Group G,I/R followed by administration of nitrate (NO3^-).NO2^-,NO3^-,and C-PTIO were intravenously *** examination of the testes and the western blot analysis of caspase-3 were *** of antioxidant enzymes and lipid peroxidation were measured. Germ cell apoptosis,oxidative stress,antioxidant enzymatic function,and lipid peroxidation in Group B were significantly higher than those in Group *** B exhibited an abnormal testicular morphology and impaired *** contrast,testicular damages were attenuated in the NO2^-treatment groups,which were caused by reduction in superoxide and peroxynitrite levels and an inhibition of caspase-3-dependent *** results of this study suggest NO2^-to be a promising therapeutic agent with anti-oxidant and anti-apoptotic properties in testicular I/R injury.

关键词： ischemia/reperfusion injury nitric oxide nitrite rat testis

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：