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Weldability evaluation and tensile strength estimation model for aluminum alloy lap joint welding using hybrid system with laser and scanner head

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中国有色金属学会会刊：英文版 2012年第S3期22卷 596-604页

作者： Dong-yoon kim Young-Whan PARK Department of Mechanical Engineering Pukyong National University

Aluminum welding using a hybrid system with a laser and scanner welding head was performed under various welding conditions to verify the feasibility of applying an aluminum alloy to a car *** experimental material was 5J32 aluminum alloy,and the laser power,welding speed,and laser incidence angle were used as the control *** weld bead shape and the tensile shear strength were evaluated in order to understand the aluminum lap joint weld *** of variance (ANOVA) was conducted to identify the effect of the process variables on the tensile shear *** strength estimation models using three different regression models were also *** input variables were the laser power,welding speed,and laser incidence angle,and the output was the tensile shear *** the models,the second-order polynomial estimation model had the best estimation performance,and the average error rate of this model was 0.058.

关键词： laser welding scanner remote welding 5J32 aluminum alloy regression model

CAD/CAM for scalable nanomanufacturing:A network-based system for hybrid 3D printing

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Microsystems & Nanoengineering 2017年第1期3卷 135-145页

作者： hae-Sung yoon Hyun-Taek Lee Ki-Hwan Jang Chung-Soo kim Hyunseo Park Dae-Wook kim Kunwoo Lee Sangkee Min Sung-Hoon Ahn BK21 Plus Transformative Training Program for Creative Mechanical and Aerospace Engineers Seoul National UniversitySeoul 08826Republic of Korea Department of Mechanical and Aerospace Engineering Seoul National UniversitySeoul 08826Republic of Korea Department of Mechanical Engineering University of Wisconsin-MadisonMadisonWI 53706USA Institute of Advanced Machines and Design Seoul National UniversitySeoul 08826Republic of Korea

Micro-and nano-structuring have been highlighted over several decades in both science and engineering *** addition to continuous efforts in fabrication techniques,investigations in scalable nanomanufacturing have been pursued to achieve reduced feature size,fewer constraints in terms of materials and dimensional complexity,as well as improved process *** this study,based on recent micro-/nanoscale fabrication processes,characteristics and key requirements for computer-aided design and manufacturing(CAD/CAM)systems for scalable nanomanufacturing were *** include a process knowledge database,standardized processing,active communication,adaptive interpolation,a consistent coordinate system,and management of peripheral *** scalable nanomanufacturing,it is important to consider the flexibility and expandability of each process,because hybrid and bridging processes represent effective ways to expand process *** an example,we describe a novel CAD/CAM system for hybrid three-dimensional(3D)printing at the *** novel hybrid process was developed by bridging aerodynamically focused nanoparticle printing,focused ion beam milling,micromachining,and spincoating *** system developed can print a full 3D structure using various inorganic materials,with a minimum process scale of 50 *** most obvious difference versus CAD/CAM at‘conventional’scales is that our system was developed based on a network to promote communication between users and process *** the network-based system,it is also possible to narrow the gap among different processes/*** anticipate that this approach can contribute to the development of CAD/CAM for scalable nanomanufacturing and a wide range of hybrid processes.

关键词： Computer-aided design and manufacturing(CAD/CAM) nanomanufacturing network-based 3D printing

Comparison of contrast sensitivity based on the surgical results for intermittent exotropia

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International Journal of Ophthalmology(English edition) 2019年第11期12卷 1725-1730页

作者： hae Rang kim Soo Jung Lee Department of Ophthalmology Haeundae Paik Hospital Inje University College of Medicine

AIM: To compare contrast sensitivity(CS) based on the surgical results for intermittent exotropia(IXT) and to examine the relationship between CS and ***: Medical records of the patients who underwent bilateral lateral rectus muscle recession for IXT between 4 and 12 years old were reviewed retrospectively. They were categorized based on the surgical results;successful correction group(n=36) and overcorrection group(esotropia ≥10 PD at 3 mo postoperatively, n=18). Using CGT-2000 test for CS was performed binocularly, and subjective reports of photophobia was investigated preoperatively and at 3 mo postoperatively. Objective photophobia was defined as a significant decrease in CS in the presence of ***: Preoperatively, there was no difference in CS between the groups. Postoperatively, under mesopic conditions, significant improvement of CS was observed at 6.3°, 4°, and 2.5° in the successful correction group and at 6.3° and 4° in the overcorrection group, regardless of glare. Under photopic conditions, at all visual angles except 0.64°, improvement in CS was noted in both groups while CS worsened significantly at 0.64° in the overcorrection group postoperatively. At all visual angles under photopic conditions postoperatively, regardless of glare, CS in the overcorrected group was significantly worse than that in the successful correction group, and CS was significantly decreased by addition of glare in both groups. All patients except one(96.4%) in the successful correction group and 8 patients(61.5%) in overcorrection group showed improvement of photophobia postoperatively, which correlated with CS under photopic conditions(P=0.001, 0.03).CONCLUSION: After surgery for IXT, CS under photopic conditions improve at all visual angles except 0.64°, while CS is significantly worse in the overcorrection group postoperatively at 0.64°. Subjective photophobia havesignificant correlation with CS under photopic conditions, and may be used as an object

关键词： contrast sensitivity intermittent exotropia overcorrection photophobia success

Effects of PWHT on Microstructure and Mechanical Properties of Weld Metals of Ni-Based Superalloy 617 and 263 for Hyper-Supercritical Power Plants

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Acta Metallurgica Sinica(English Letters) 2016年第12期29卷 1107-1118页

作者： Jeong Kil kim hae Ji Park Deog Nam Shim Doosan Heavy Industries and Construction ChangwonGeongnam Korea

It is well known that solid solution-strengthened alloy 617 and γ′ precipitation-strengthened alloy 263 have excellent mechanical properties and corrosion resistance at high temperatures. Hyper-supercritical power plants work at temperatures above 700 ℃, and these superalloys are considered candidate materials for steam turbines components of these power plants. In this study, gas tungsten arc weldability of these superalloys was evaluated, and the effects of post- weld heat treatment （PWHT） on the microstructural characteristics and the mechanical properties of their weld metals were investigated. Scanning transmission electron microscopy, energy-dispersive spectroscopy and electron probe microanalysis were utilized for the investigation. The experimental results confirmed that these weld metals had different characteristics in microstructure and mechanical properties. PWHT resulted in the precipitation of intergranular carbides, γ′ particles and an increase in tensile strength of these superalloy weld metals. Furthermore, fine γ′ particles, which were not detected in the as-welded metal of alloy 263, were precipitated after PWHT and those particles were the reason for the drastic increase in tensile strength.

关键词： Superalloy Welding Precipitation Segregation

Effects of edible insect extracts on the antioxidant, physiochemical, and microbial properties of Tteokgalbi during refrigerated storage

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Food Bioscience 2023年第2期52卷 326-333页

作者： hae In Yong Tae-Kyung kim Ji yoon Cha Jae Hoon Lee Min-Cheol Kang Samooel Jung Yun-Sang Choi Research Group of Food Processing Korea Food Research InstituteWanju55365Republic of Korea Division of Animal and Dairy Science Chungnam National UniversityDaejeon34134Republic of Korea

In this study,Tteokgalbi,a meat product,was prepared with edible insect larvae extracts and its antioxidant,physiochemical,and microbial properties were evaluated during refrigerated *** prepared with 2%*** and 2%*** showed the highest radical-scavenging activity and metal-chelating activity,but the lowest thiobarbituric acid reactive substance(TBARS)value,among the treatments(P<0.05).In addition,those antioxidant activities were the lowest and the TBARS value was the highest in control Tteokgalbi(P<0.05)during all storage *** prepared with 2%*** showed the highest brownness index,pH,and cooking yield,but the lowest shear force value(P<0.05).During all storage days,the total aerobic bacteria level did not differ significantly among the *** conclusion,*** extracts(2%)were effective as antioxidants,inhibiting lipid oxidation,and improving the quality properties of Tteokgalbi,without negatively affecting microbial *** results confirmed that the edible insect extracts have industrial value as a food additive.

关键词： Edible insect Lipid oxidation Natural antioxidant Refrigerated storage Tteokgalbi

Distinctive clinical features of spontaneous pneumoperitoneum in neonates: A retrospective analysis

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World Journal of Clinical Cases 2022年第23期10卷 8124-8132页

作者： Soo-Hong kim Yong-Hoon Cho hae-Young kim Department of Surgery Pusan National University Yangsan HospitalPusan National University School of MedicineYangsan 50612South Korea Research Institute for Convergence of Biomedical Science and Technology Pusan National University Yangsan HospitalYangsan 50612South Korea

BACKGROUND Spontaneous pneumoperitoneum(SP) without gastrointestinal perforation rarely occurs in neonates, with most SP cases being idiopathic. Although SP usually follows a benign clinical course with favorable prognosis, it can become lifethreatening in certain situations. In these cases, urgent surgical intervention may be required. Therefore, it may be difficult to decide when or how to perform prompt *** To demonstrate the distinct clinical features of SP to guide appropriate management by comparing characteristics between SP and typical pneumoperitoneum secondary to gastrointestinal *** We retrospectively reviewed electronic medical records and identified 37 neonates with radiological evidence of pneumoperitoneum who were treated at our institution. Clinical variables were compared between neonates with SP without gastrointestinal perforation(Group A) and those with pneumoperitoneum secondary to gastrointestinal perforation(Group B). Clinical variables between groups were compared using Student’s t-test and the chi-square test. The risk factors related to mortality were examined using multi-logistic regression *** Group A comprised 35.1%(13/37) of the patients. The frequency of persistent pulmonary hypertension(53.8%) and pneumothorax(46.2%) before the development of pneumoperitoneum was significantly higher in group A than in group B(P =0.004). Platelet count and partial pressure of arterial oxygen(PaO) were significantly lower in group A(P = 0.015 and 0.025, respectively). Overall mortality was significantly higher in group A than in group B(76.9% vs 16.7%, P = 0.001). Only preterm infants were significantly associated with high mortality(P = 0.041;odds ratio = 18.0). Accompaniment with persistent pulmonary hypertension and pneumothorax were also significantly high(P = 0.004) in group A, but these were not strongly associated with high *** This study identified a higher mortality rate in patients w

关键词： Spontaneous pneumoperitoneum Thrombocytopenia Persistent pulmonary hypertension Pneumothorax Preterm

Atomic layer deposition for nanoscale oxide semiconductor thin film transistors:review and outlook

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International Journal of Extreme Manufacturing 2023年第1期5卷 153-180页

作者： Hye-Mi kim Dong-Gyu kim yoon-Seo kim Minseok kim Jin-Seong Park Division of Materials Science and Engineering Hanyang University222 Wangsimni-roSeongdong-guSeoul 04763Republic of Korea

Since the first report of amorphous In–Ga–Zn–O based thin film transistors,interest in oxide semiconductors has *** offer high mobility,low off-current,low process temperature,and wide flexibility for compositions and ***,depositing oxide semiconductors using conventional processes like physical vapor deposition leads to problematic issues,especially for high-resolution displays and highly integrated memory *** approaches have limited process flexibility and poor conformality on structured *** layer deposition(ALD)is an advanced technique which can provide conformal,thickness-controlled,and high-quality thin film ***,studies on ALD based oxide semiconductors have dramatically increased *** so,the relationships between the film properties of ALD-oxide semiconductors and the main variables associated with deposition are still poorly understood,as are many issues related to *** this review,to introduce ALD-oxide semiconductors,we provide:(a)a brief summary of the history and importance of ALD-based oxide semiconductors in industry,(b)a discussion of the benefits of ALD for oxide semiconductor deposition(in-situ composition control in vertical distribution/vertical structure engineering/chemical reaction and film properties/insulator and interface engineering),and(c)an explanation of the challenging issues of scaling oxide semiconductors and ALD for industrial *** review provides valuable perspectives for researchers who have interest in semiconductor materials and electronic device applications,and the reasons ALD is important to applications of oxide semiconductors.

关键词： atomic layer deposition(ALD) oxide semiconductor thin film transistor(TFT)

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

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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

The Role of Relative Spinal Motion during Feline Galloping for Speed Performance

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Journal of Bionic Engineering 2014年第4期11卷 517-528页

作者： Young Kook kim Jongwon Park Byungho yoon Kyung-Soo kim Soohyun kim Robotics Program Korea Advanced Institute of Science and Technology (KAIST) Daejeon 305-701 Republic of Korea Department of Mechanical Engineering Korea Advanced Institute of Science and Technology (KAIST) Daejeon 305-701 Republic of Korea

Felines use their spinal column to increase their running speed at rapid locomotion performance. However, its motion profile behavior during fast gait locomotion has little attention. The goal of this study is to examine the relative spinal motion profile during two different galloping gait speeds. To understand this dynamic behavior trend, a dynamic motion of the feline animal （Felis catus domestica） was measured and analyzed by motion capture devices. Based on the experiments at two different galloping gaits, we observed a significant increase in speed （from 3.2 m.s-1 to 4.33 m.s-1） during the relative motion profile synchronization between the spinal （range： 118.86~ to 168.00~） and pelvic segments （range： 46.35~ to 91.13~） during the hindlimb stance phase （time interval： 0.495 s to 0.600 s）. Based on this discovery, the relative angular speed profile was applied to understand the possibility that the role of the relative motion match during high speed locomotion generates bigger ground reaction force.

关键词： feline galloping galloping gait pattern relative spinal motion speed performance phase match