检索结果-南通市图书馆

Influence of undissolved second-phase particles on dynamic recrystallization behavior of Mg–7Sn–1Al–1Zn alloy during low-and high-temperature extrusions

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2021年第12期71卷 87-97页

作者： Hyun Ji Kim Sang-Cheol Jin jae-Gil Jung sung Hyuk park School of Materials Science and Engineering Kyungpook National UniversityDaegu41566Republic of Korea Implementation Research Division Korea Institute of Materials ScienceChangwon51508Republic of Korea

This study investigates the effects of fine and coarse undissolved particles in a billet of the Mg–7 Sn–1 Al–1 Zn(TAZ711)alloy on the dynamic recrystallization(DRX)behavior during hot extrusion at low and high temperatures and the resultant microstructure and mechanical properties of the *** this end,partially homogenized(PH)and fully homogenized(FH)billets are extruded at temperatures of250 and 450°*** PH billet contains fine and coarse undissolved Mg_(2) Sn particles in the interdendritic region and along the grain boundaries,*** fine particles(<1μm in size)retard DRX during extrusion at 250°C via the Zener pinning effect,and this retardation causes a decrease in the area fraction of dynamically recrystallized(DRXed)grains of the extruded *** addition,the inhomogeneous distribution of fine particles in the PH billet leads to the formation of a bimodal DRXed grain structure with excessively grown grains in particle-scarce *** contrast,in the FH billet,numerous nanosized Mg_(2) Sn precipitates are formed throughout the material during extrusion at 250°C,which,in turn,leads to the formation of small,uniform DRXed grains by the grain-boundary pinning effect of the *** the PH billet is extruded at the high temperature of 450°C,the retardation effect of the fine particles on DRX is weakened by their dissolution in theα-Mg matrix and the increased extent of thermally activated grain-boundary *** contrast,the coarse Mg_(2) Sn particles in the billet promote DRX during extrusion through the particle-stimulated nucleation phenomenon,which results in an increase in the area fraction of DRXed *** both low and high extrusion temperatures,the extruded material fabricated using the PH billet,which contains both fine and coarse undissolved particles,has a lower tensile strength than that fabricated using the FH billet,which is virtually devoid of second-phase *** lower strength of the former is attributed mai

关键词： Mg–Sn alloy Second-phase particle Extrusion Homogenization Dynamic recrystallization

Cystic Brunner's gland hamartoma in the duodenum:A case report

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2009年第39期15卷 4980-4983页

作者： Beom Jin park Min Ju Kim Jeong Hyeon Lee sung-Soo park Deuk jae sung sung Bum Cho Department of Radiology Korea UniversityCollege of MedicineAnam Hospital Department of Pathology Korea UniversityCollege of MedicineAnam Hospital Department of Surgery Korea UniversityCollege of MedicineAnam Hospital

Cystic Brunner's gland hamartoma in the duodenum is exceedingly rare,although microscopic examination may sometimes reveal a Brunner's gland hamartoma containing dilated ducts in the *** present a case of large cystic Brunner's gland hamartoma in the duodenum with a long stalk,which is described in light of multidetector-row computed tomography,magnetic resonance imaging,and a modified small bowel series,together with pathologic correlation and differential diagnosis.

关键词： Brunner's gland Hamartoma Duodenum Multidetector-row computed tomography Magnetic resonance imaging

WRA-Net:Wide Receptive Field Attention Network for Motion Deblurring in Crop and Weed Image

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Plant Phenomics 2023年第2期5卷 174-194页

作者： Chaeyeong Yun Yu Hwan Kim sung jae Lee Su Jin Im Kang Ryoung park Division of Electronics and Electrical Engineering Dongguk University30 Pildong-ro 1-gilJung-guSeoul 04620Republic of Korea

Automatically segmenting crops and weeds in the image input from cameras accurately is essential in various agricultural technology fields,such as herbicide spraying by farming robots based on crop and weed segmentation ***,crop and weed images taken with a camera have motion blur due to various causes(e.g.,vibration or shaking of a camera on farming robots,shaking of crops and weeds),which reduces the accuracy of crop and weed ***,robust crop and weed segmentation for motion-blurred images is ***,previous crop and weed segmentation studies were performed without considering motion-blurred *** solve this problem,this study proposed a new motion-blur image restoration method based on a wide receptive field attention network(WRA-Net),based on which we investigated improving crop and weed segmentation accuracy in motion-blurred ***-Net comprises a main block called a lite wide receptive field attention residual block,which comprises modified depthwise separable convolutional blocks,an attention gate,and a learnable skip *** conducted experiments using the proposed method with 3 open databases:BoniRob,crop/weed field image,and rice seedling and weed *** to the results,the crop and weed segmentation accuracy based on mean intersection over union was 0.7444,0.7741,and 0.7149,respectively,demonstrating that this method outperformed the state-of-the-art methods.

关键词： Net shaking image

Comparative study of extrudability, microstructure, and mechanical properties of AZ80 and BA53 alloys

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2023年第1期11卷 249-258页

作者： Sang-Cheol Jin jae Won Cha Jongbin Go Jun Ho Bae sung Hyuk park School of Materials Science and Engineering Kyungpook National UniversityDaegu 41566Republic of Korea Department of Materials Science and Engineering Kyoto UniversityKyoto 606-8501Japan Advanced Metals Division Korea Institute of Materials ScienceChangwon 51508Republic of Korea

The extrudability,microstructural characteristics,and tensile properties of the Mg–5Bi–3Al(BA53)alloy are investigated herein by comparing them with those of a commercial Mg–8Al–0.5 Zn(AZ80)*** AZ80 is extruded at 400℃,severe hot cracking occurs at exit speeds of 4.5 m/min or *** contrast,BA53 is successfully extruded without any surface cracking at 400℃ and at high exit speeds of 21–40 m/*** extruded at 3 m/min(AZ80–3)and 40 m/min(BA53–40),both AZ80 and BA53 exhibited completely recrystallized microstructures with abasal ***,BA53–40 has a coarser grain structure owing to grain growth promoted by the high temperature in the deformation ***80–3 contains a continuous network of Mg_(17)Al_(12) particles along the grain boundaries,which form via static precipitation during natural air-cooling after the material exits the extrusion ***53–40 contains coarse Mg_(3)Bi_(2) particles aligned parallel to the extrusion direction along with numerous uniformly distributed fine Mg_(3)Bi_(2) ***80–3 has higher tensile strength than BA53–40 because the relatively finer grains and larger number of solute atoms in AZ80–3 result in stronger grain-boundary and solid-solution hardening effects,*** BA53 is extruded at a high temperature and extrusion speed of 400℃ and 40 m/min,respectively,the extruded material has a high tensile yield strength of 188 *** can be primarily attributed to the large particle hardening effect resulting from the numerous fine Mg_(3)Bi_(2) particles.

关键词： Mg-Bi-Al alloy Extrusion Hot cracking Second phase Tensile properties

Effects of Al addition on microstructure and mechanical properties of extruded Mg-3Bi alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2022年第7期10卷 1887-1898页

作者： Sang-Cheol Jin jae Won Cha Jun Ho Bae Hui Yu sung Hyuk park School of Materials Science and Engineering Kyungpook National UniversityDaegu 41566Republic of Korea Implementation Research Division Korea Institute of Materials ScienceChangwon 51508Republic of Korea School of Materials Science and Engineering Hebei University of TechnologyTianjin 300130China

Effects of Al addition to a Mg±Bi binary alloy on its microstructural characteristics and tensile properties after extrusion are investigated via extrusion of Mg-3Bi±x Al(x=0,1,and 2 wt%)billets and analysis of the extruded *** Al addition negligibly affects the second-phase particles of the extruded alloy;however,an increase in the Al content causes significant decreases in the average grain size and maximum texture intensity of the extruded material owing to an increase in the area fraction of dynamically recrystallized(DRXed)*** Al addition improves the strength of the extruded alloy;this improvement is attributed to the enhanced grain-boundary hardening and solid-solution hardening effects induced by grain refinement and Al solute atoms,*** the Al content increases from 0 wt%to 1 wt%and 2 wt%,the tensile elongation increases substantially from 2.8%to 9.4%and 16.9%,*** reduction in the number and size of un DRXed grains with increasing Al content suppresses the formation and coalescence of cracks in the un DRXed grains during tension,which results in a significant improvement in the tensile ductility of the extruded *** tensile deformation,large undesirable twins that act as crack initiation sites are locally formed in the un DRXed grains of the Mg-3Bi alloy,whereas relatively smaller twins are uniformly formed in both the DRXed and the un DRXed grains of the Mg-3Bi-2Al ***,the extruded Mg-3Bi-2Al alloy has a substantially higher tensile yield strength±elongation product(2924 MPa%)than the extruded Al-free B3 alloy(381 MPa%).

关键词： Mg-Bi-Al alloy Extrusion Microstructure Strength Ductility

A feasible route to produce 1.1 GPa ferritic-based low-Mn lightweight steels with ductility of 47%

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2022年第22期117卷 225-237页

作者： Kwang Kyu Ko Hyo Ju Bae Eun Hye park Hyeon-Uk Jeong Hyoung Seok park jae Seok Jeong Jung Gi Kim Hyokyung sung Nokeun park jae Bok Seol Department of Materials Engineering and Convergence Technology Center for K-metalGyeongsang National University(GNU)Jinju 52828South Korea School of Materials Science and Engineering Yeungnam UniversityGyeongbuk 38541South Korea Materials Research Team R&D Hyundai MobisYongin 16891South Korea Materials Technology Development Team Doosan Heavy Industries&ConstructionChangwon 51711South Korea

High- and medium-Mn (H/M-Mn) base lightweight steels are a class of ultrastrong structural materials with high ductility compared to their low-Mn counterparts with low strength and poor ***, producing these H/M-Mn materials requires the advanced or high-tech manufacturing techniques, which can unavoidably provoke labor and cost concerns. Herein, we have developed a facilestrategy that circumvents the strength–ductility trade-off in low-Mn ferritic lightweight steels, by employing low-temperature tempering-induced partitioning (LTP). This LTP treatment affords a typical Fe-2.8Mn-5.7Al-0.3C (wt.%) steel with a heterogeneous size-distribution of metastable austenite embeddedin a ferrite matrix for partitioning more carbon into smaller austenite grains than into the larger austenite ones. This size-dependent partitioning results in slip plane spacing modification and lattice strain,which act through dislocation engineering. We ascribe the simultaneous improvement in strength andtotal elongation to both the size-dependent dislocation movement in austenite grains and the controlleddeformation-induced martensitic transformation. The low-carbon-partitioned large austenite grains increase the strength and ductility as a consequence of the combined martensitic transformation andhigh dislocation density-induced hardening and by interface strengthening. Additionally, high-carbonpartitioned small austenite grains enhance the strength and ductility by planar dislocation glide (inthe low strain regime) and by cross-slipping and delayed martensitic transformation (in the high strainregime). The concept of size-dependent dislocation engineering may provide different pathways for developing a wide range of heterogeneous-structured low-Mn lightweight steels, suggesting that LTP maybe desirable for broad industrial applications at an economic cost.

关键词： Low-Mn lightweight steel Carbon partitioning Metastable austenite Dislocation movement

Comparison of the efficacy and safety of once-daily dosing and on-demand use of udenafil for type 2 diabetic patients with erectile dysfunction

在线全文

学校读者我要写书评

暂无评论

Asian Journal of Andrology 2015年第1期17卷 143-148,I0011,I0012页

作者： Soon Hyun park sung Woo park Bong Yun Cha Ie Byung park Kyung Wan Min Yeon Ah sung Tae Hwa Kim jae Min Lee Kang Seo park Department of Internal Medicine Eulji University School of Medicine Daejeon 302-799 South Korea Department of Endocrinology and Metabolism Kangbuk Samsung Hospital Sungkyunkwan University School of Medicine Seou1110-746 South Korea Department of Endocrinology and Metabolism College of Medicine the Catholic University of Korea Seou1137-701 South Korea Department of Internal Medicine Gachon University of Medicine and Science Graduate School of Medicine Incheon 405-760 South Korea Department of Internal Medicine Eulji University School of Medicine Seou1139-872 South Korea Department of Endocrinology Ewha Woman's University School of Medicine Seoul 158-710 South Korea Department of Internal Medicine College of Medicine Hanyang University Seoul 133-792 South Korea.

We compared the efficacy and safety between once-daily dosing and on-demand use of udenafil for type 2 diabetic patients with erectile dysfunction （ED）. A multi-center, randomized, open-label, parallel-group, 12-week study was conducted. 161 patients who improved with on-demand 200 mg of udenafil according to Sexual Encounter Profile （SEP） diary Question 2 and 3 （Q2 and Q3） were randomized into 200 mg on-demand （n = 80） or 50 mg once-daily （n = 81） dosing groups for 8 weeks. The dosing period was followed by a 4-week treatment-free period. The primary efficacy endpoint was the change of the International Index of Erectile Function （IIEF） erectile function domain （EFD） score. The secondary efficacy endpoints included changes to the SEP diary Q2, Q3, IIEF Q3, Q4, other domains of IIEF, Global Assessment Question, and shift to the normal rate （EFD 〉 26）. Vascular endothelial markers were also assessed. The IIEF-EFD score of both groups improved after 8 weeks of treatment （P 〈 0.0001）. There was no statistically significant difference between two groups. Improvement was not maintained after the treatment-free follow-up period. Similar results were observed in the secondary efficacy endpoints. There was also no significant difference in vascular endothelial markers. Daily udenafil was well-tolerated, and there was no significant difference in the adverse drug reactions and adverse events between the two groups. Flushing and headache were the most frequent adverse events. Both regimens improved ED in diabetic patients and were well-tolerated. Further studies are needed to assess the effect of daily udenafil treatment in diabetic patients.

关键词： erectile dysfunction International Index of Erectile Function once-daily dosing ptiosphodiesterase type 5 inhibitor type 2 diabetes mellitus udenafil

Do you have what it takes for challenging endoscopic submucosal dissection cases?

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2011年第31期17卷 3580-3584页

作者： Kyoung-Oh Kim sung Jung Kim Tae Hyeon Kim Jong-jae park Division of Gastroenterology and Hepatology Department of Internal MedicineHallym University Medical Center Division of Gastroenterology and Hepatology Department of Internal MedicineWonkwang University Hospital Division of Gastroenterology and Hepatology Department of Internal MedicineKorea University Guro Hospital Korea University College of Medicine

Endoscopic submucosal dissection(ESD) is a widely accepted treatment for early gastric cancer(EGC),especially in Korea and *** criteria for the therapeutic use of ESD for EGC have been expanded ***,attention should be drawn to the technical feasibility of the ESD treatment which depends on a lesion's location,size or fibrosis level,or operator's *** the case of a lesion with a high level of difficulty,a more experienced operator is ***,the treatment for a lesion with a high level of difficulty should be performed according to the degree of the operator's *** this paper,the authors describe the ESD procedure for lesions with a high level of difficulty.

关键词： Endoscopic submucosal dissection Anatomical location Technical feasibility

Proteomic identification of cryostress in epididymal spermatozoa

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Animal Science and Biotechnology 2017年第2期8卷 478-489页

作者： sung jae Yoon Md Saidur Rahman Woo sung Kwon Do Yeal Ryu Yoo Jin park Myung Geol Pang Department of Animal Science&Technology Chung-Ang UniversityAnseongGyeonggi-Do 456-756Republic of Korea

Background： Cryopreservation of epididymal spermatozoa is important in cases in which it is not possible to collect semen using normal methods, as the sudden death of an animal or a catastrophic injury. However, the freezing and thawing processes cause stress to spermatozoa, including cold shock, osmotic damage, and ice crystal formation,thereby reducing sperm quality. We assessed the motility（%）, motion kinematics, capacitation status, and viability of spermatozoa using computer-assisted sperm analysis and Hoechst 33258/chlortetracycline fluorescence ***, we identified proteins associated with cryostress using a proteomic approach and performed western blotting to validate two-dimensional electrophoresis（2-DE） results using two commercial ***： Cryopreservation reduced viability（%）, motility（%）, straight-line velocity（VSL）, average path velocity（VAP）, amplitude of lateral head displacement（ALH）, and capacitated spermatozoa, whereas straightness（STR）and the acrosome reaction increased after cryopreservation（P 3 fold, P ＆lt; 0.05） before and after cryopreservation. The proteins differentially expressed following cryopreservation are putatively related to several signaling pathways, including the ephrinR-actin pathway, the ROS metabolism pathway, actin cytoskeleton assembly, actin cytoskeleton regulation,and the guanylate cyclase ***： The results of the current study provide information on epididymal sperm proteome dynamics and possible protein markers of cryo-stress during cryopreservation. This information will further the basic understanding of cryopreservation and aid future studies aiming to identify the mechanism of cryostress responses.

关键词： Cryopreservation Cryostress Protein Spermatozoa