检索结果-南通市图书馆

Microstructural evolution and mechanical properties of binary Mg-xBi(x=2,5,and 8 wt%)alloys

Journal of Magnesium and Alloys 2021年第3期9卷 983-994页

作者： Hui Yu Shaoda Fan Shuaiju Meng jae ok choi Zhongjie Li Yohan Go Young Min Kim Weimin Zhao Bong Sun You Kwang Seon Shin School of Materials Science and Engineering Hebei University of TechnologyXiping Road 5340Tianjin 300130China

The microstructures and mechanical properties of Mg-x Bi(x=2,5,and 8 wt%)were investigated compared with pure *** ascast Mg-Bi billets consist of dendriticα-Mg grain matrix,divorced eutectic Mg_(3)Bi_(2) phase and secondary precipitated Mg_(3)Bi_(2) *** homogenization,secondary precipitated Mg_(3)Bi_(2) particles were all dissolved into the matrix,while most of the divorced eutectic Mg_(3)Bi_(2) intermetallic compounds *** the as-extruded samples exhibit fully dynamic recrystallization(DRX)and the average grain size decreases and the amount of nano-scale Mg_(3)Bi_(2) precipitates increases with increasing Bi ***,Bi alloying has little influence on the texture of the as-extruded pure Mg,with all the samples showing typical basal *** the results of grain refinement and precipitation hardening,the strengths of the as-extruded samples increase under both tensile and compressive ***,the yield asymmetry significantly decreases with Bi ***,all the as-extruded samples represent similar ductility under compression,while the tensile elongation first increases and then decreases with more Bi *** as-extruded Mg-5Bi alloy demonstrates good combination of strength and ***,Mg-8Bi alloy displays lower tensile ductility than that of Mg-5Bi alloy due to the presence of abundant undissolved coarse Mg_(3)Bi_(2) particles,which act as cracking sources during tensile ***,the strain hardening rate,strain hardening exponent n,and hardening capacity Hc are greatly reduced by Bi addition,mainly owing to the enhanced synergy effects of grain refinement and numerous Mg_(3)Bi_(2) precipitates.

关键词： Mg-Bi Mechanical properties Microstructure Strain hardening

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

Tidal Forecast for Final Closure of Saemangeum Tidal Dike

引用

China Ocean Engineering 2010年第3期24卷 467-480页

作者： Byung Ho choi jae Wan HA Kwang Oh KO Dae Soo EO Kyeong ok KIM Department of Civil and Environmental Engineering Sungkyunkwan University Hyundai E&C Co. Ltd. Korea Rural Community Corporation Korea Ocean Research & Development Institute

The Saemangeum project includes well-developed tidal flats, two estuaries of the Mankyeong and Dongjin rivers, and a chain of small iskands in the outer area off the dike by reclaiming a surface area of 40100 ha. A long sea dike of 30 km has been constructed in the mid-west area of Korea. This paper describes the construction of tidal dikes focusing on the final closure operation performed in April, 2006 employing intermediate technology. Predictive modelling was also carried out to predict the real-time flow fields during the gradual closure operation of the final stage.

关键词： mathematical modelling dams barrages & reservoirs hydraulics & hydrodynamics sea defence

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

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

Short-circuit Current Characteristics of Wind Generators

引用

电力系统自动化 2012年第8期36卷 110-114页

作者： Seung-jae LEE Myeon-Song choi Department of Electrical Engineering Myongji University

To study the effects of wind generators on distribution system protection,the short-circuit current(SCC) characteristics of wind generators is *** there are many researches on the issue,a clear agreement has not been reached so *** SCC characteristics for different wind generators are *** simulation is performed in the same system integrated with different kinds of wind generators,and their results are compared with those reported in IEEE *** detection possibility by overcurrent relay(OCR)is discussed based on the simulation results.

关键词：风力发电机组短路电流电流特性配电系统 PSCAD 过流继电器 IEEE 通过检测

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

Adsorption properties of polycarboxylate ether-based superplasticizer on cement particles and their resultant dispersion

引用

Frontiers of Structural and Civil Engineering 2022年第4期16卷 506-514页

作者： Jinyoung YOON Byoung Il choi jae Hong KIM Department of Structural Engineering Research Korea Institute of Civil Engineering and Building Technology(KICT)Goyang 10223Republic of Korea System Safety Research Department Korea Shipbuilding and Offshore EngineeringSeongnam 13591Republic of Korea Department of Civil and Environmental Engineering Korea Advanced Institute of Science and TechnologyDaejeon 34141Republic of Korea

The cement dispersion performance of a polycarboxylate(PCE)-based superplasticizer is highly related to their adsorption behaviors as a function of *** study evaluated effects of PCEs on rheological properties of cementitious ***,characteristics of PCEs were characterized via permeation chromatography(GPC)and Fourier-transform infrared spectrometry(FT-IR).The adsorption behavior of single and blended PCEs on cementitious composites was identified using total organic carbon analyzer(TOC).Based on the measurement of PCE adsorption,the changes of rheological properties of cementitious materials as well as the number of dispersed cement particles were characterized using a rheometer and laser spectroscopy,*** experimental results support the systematic mechanism of PCE adsorption,cement dispersion,and the decrease in viscosity of cementitious materials.

关键词： adsorption polycarboxylate superplasticizer rheology dispersion

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

Evaluation of SWAT sub-daily runoff estimation at small agricultural watershed in Korea

引用

Frontiers of Environmental Science & Engineering 2013年第1期7卷 109-119页

作者： Ganga Ram Maharjan Youn Shik Park Nam Won Kim Dong Seok Shin jae Wan choi Geun Woo Hyun Ji-Hong Jeon Yong Sik ok Kyoung jae Lim GIS Environmental System Laboratory Department of Regional Infrastructure Engineering Kangwon National University Chuncheon 200-701 R. O. Korea Department of Agricultural and Biological Engineering Purdue University West Lafayette IN 47907 USA Water-Resource Research Department Korea Institute of Construction Technology Goyang 411-712 R. O. Korea National Institute of Environmental Research Incheon 404-708 R. 0. Korea Department of Water Research Division Gangwon Institute of Health and Environment Chuncheon 200 822 R. O. Korea Department of Environmental Engineering Andong National University Andong 760-380 R. O. Korea Department of Biological Environ-ment Kangwon National University'Chuncheon 700-711 R. O. Korea

A study was undertaken for the prediction of runoff flow from 0.8 ha field-sized agricultural watershed in South Korea using Soil and Water Assessment Tool (SWAT) sub-daily. The SWAT model with sub-daily configuration predicted flow from the watershed within the range of acceptable accuracy. The SWAT sub-daily simulations were carried out for a total of 18 rainfall events, 9 each for calibration and validation. Overall trend and extent of matching simulated flow for the rainfall events in 2007–2008 with measured data during the calibration process were coefficient of determination (R2) value of 0.88 and Nash and Sutcliffe Efficiency (ENS) value of 0.88. For validation, R2 and ENS values were 0.9 and 0.84, respectively. Whereas R2 and ENS values for simulation results using daily rainfall data were 0.79 and ?0.01, respectively, that were observed to be out of acceptable limits for the model simulation. The importance of higher time resolution (hourly) precipitation records for flow simulation were evaluated by comparing R2 and ENS with 15 min, 2 h, 6 h and 12 h precipitation data, which resulted in lower statistics with increases in time resolution of precipitation data. The SWAT sub-daily sensitivity analysis was performed with the consideration of hydraulic parameter and was found as in the rank order of CN2 (curve number), ESCO (soil evaporation compensation factor), GW_DELAY (ground water delay time), ALPHA_BF (base flow alpha factor), GWQMN (a threshold minimum depth of water in the shallow aquifer required for return flow to occur), REVAPMN (minimum depth of water in shallow aquifer for re-evaporation to occur), LAT_TIME (lateral flow travel time) respectively. These sensitive parameters were evaluated at 10% higher a

关键词： Soil and Water Assessment Tool (SWAT) sub-daily simulation runoff rainfall

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

Toxocara optic neuropathy: clinical features and ocular findings

引用

International Journal of Ophthalmology(English edition) 2018年第3期11卷 520-523页

作者： Kwang-Dong choi jae-Hwan choi Seo-Young choi jae Ho Jung Department of Neurology Pusan National University Hospital Medical Research Institute Pusan National University Department of Neurology Pusan National University Yangsan Hospital Department of Ophthalmology Pusan National University Yangsan Hospital Research Institute for Convergence of Biomedical Science and Technology Pusan National University Yangsan Hospital

We evaluated thirteen eyes of twelve patients diagnosed clinically and serologically with Toxocara optic neuropathy. Eleven patients had unilateral involvement and one patient had bilateral optic neuropathy. Eight patients （66.7%） had a possible infection source to Toxocara. Six patients （50%） had painless acute optic neuropathy. Ten eyes had asymmetric, sectorial optic disc edema with peripapillary infiltration and three eyes had diffuse optic disc edema. Eosinophilia was noted in five patients （41.7%） and optic nerve enhancement was observed in eight of eleven eyes （72.7%） with available orbit magnetic resonance imaging （MRI）. Mean visual acuity significantly improved following treatment [mean logarithmic of the minimum angle of resolution （IogMAR） 0.94±0.56 at baseline and 0.47±0.59 at the final （P=0.02）]. Asymmetric optic disc edema with a peripapillary lesion and a history of raw meat ingestion were important clues for diagnosing Toxocara optic neuropathy. Additionally, Toxocara IgG enzymelinked immunosorbent assay （ELISA） test and evaluating eosinophil may be helpful for diagnosis.

关键词： optic neuropathy toxocariasis ocular toxocariasis Toxocara optic neuropathy

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

LIMITED TOMOGRAPHY RECONSTRUCTION VIA TIGHT FRAME AND SIMULTANEOUS SINOGRAM EXTRAPOLATION

引用

Journal of Computational Mathematics 2016年第6期34卷 575-589页

作者： jae Kyu choi Bin Dong Xiaoqun Zhang Institute of Natural Sciences Shanghai Jiao Tong University Shanghai China Beijing International Center for Mathematical Research Peking University Beijing China Institute of Natural Sciences School of Mathematical Sciences and MOE-LSC Shanghai Jiao Tong University Shanghai China

X-ray computed tomography （CT） is one of widely used diagnostic tools for medical and dental tomographic imaging of the human body. However, the standard filtered back- projection reconstruction method requires the complete knowledge of the projection data. In the case of limited data, the inverse problem of CT becomes more ill-posed, which makes the reconstructed image deteriorated by the artifacts. In this paper, we consider two dimensional CT reconstruction using the projections truncated along the spatial direc- tion in the Radon domain. Over the decades, the numerous results including the sparsity model based approach has enabled the reconstruction of the image inside the region of interest （ROI） from the limited knowledge of the data. However, unlike these existing methods, we try to reconstruct the entire CT image from the limited knowledge of the sinogram via the tight frame regularization and the simultaneous sinogram extrapolation. Our proposed model shows more promising numerical simulation results compared with the existing sparsity model based approach.

关键词： X-ray computed tomography Limited tomography Wavelet frame Data driventight frame Bregmanized operator splitting algorithm Sinogram extrapolation.

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

Ethanol extracts of Hizikia fusiforme induce apoptosis in human prostate cancer PC3 cells via modulating a ROS-dependent pathway

引用

Asian Pacific Journal of Tropical Biomedicine 2020年第2期10卷 78-86页

作者： Eun ok choi Hyesook Lee Cheol Park Gi-Young Kim Hee-jae Cha Suhkmann Kim Heui-Soo Kim You-Jin Jeon Hye Jin Hwang Yung Hyun choi Anti-Aging Research Center Dong-eui UniversityBusan 47340Republic of Korea Department of Biochemistry College of Korean MedicineDong-eui UniversityBusan 47227Republic of Korea Department of Molecular Biology College of Natural SciencesDong-eui UniversityBusan 47340Republic of Korea Laboratory of Immunobiology Department of Marine Life SciencesJeju National UniversityJeju 63243Republic of Korea Department of Parasitology and Genetics Kosin University College of MedicineBusan 49267Republic of Korea Department of Chemistry College of Natural SciencesCenter for Proteome Biophysics and Chemistry Institute for Functional MaterialsPusan National UniversityBusan 46241Republic of Korea Department of Biological Sciences College of Natural SciencesPusan National UniversityBusan 46241Republic of Korea Department of Food and Nutrition College of NursingHealthcare Sciences&Human EcologyDong-eui UniversityBusan 47340Republic of Korea

Objective:To investigate whether ethanol extracts of Hizikia fusiforme could induce apoptosis in human prostate cancer PC3 ***:Cell viability was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium *** and mitochondrial membrane potential(MMP)were measured using flow cytometry in PC3 *** damage was assessed by nuclear staining and DNA fragmentation *** of apoptosis-associated proteins were determined by Western blotting *** of caspase-3,-8,and-9 were determined by colorimetric ***,intracellular reactive oxygen species(ROS)generation was detected using a flow cytometer and fluorescence ***:Treatment of PC3 cells with ethanol extracts of Hizikia fusiforme inhibited proliferation,which was associated with induction of apoptosis,and accompanied by increased expression of Fas,Fas-ligand(Fas L),Bax and t Bid,and decreased expression of *** addition,ethanol extracts of Hizikia fusiforme reduced c-Flip expression and activated caspase-8,-9 and-3,resulting in an increase in poly(ADP-ribose)polymerase(PARP)***,in the presence of a pan-caspase inhibitor,ethanol extracts of Hizikia fusiforme-mediated growth inhibition and apoptosis were significantly *** extracts of Hizikia fusiforme also destroyed the integrity of mitochondria due to the loss of MMP,leading to cytosolic release of cytochrome ***,the levels of ROS were markedly increased by treatment with ethanol extracts of Hizikia fusiforme,which was significantly suppressed by the ROS scavenger *** investigation of whether ethanol extracts of Hizikia fusiforme-induced apoptosis was related to the generation of ROS was conducted and the results showed that N-acetyl-L-cysteine fully blocked ethanol extracts of Hizikia fusiforme-induced apoptotic events including loss of MMP,activation of caspase-3,the cytosolic release of cytochrome c and ***:E

关键词： Hizikia fusiforme Apoptosis Prostate cancer cells Caspase Reactive oxygen species

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：