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Development of XY scanner with minimized coupling motions for high-speed atomic force microscope

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Journal of Central South University 2011年第3期18卷 697-703页

作者： PARK Jong-kyu moon won-kyu Department of Mechanical Engineering Changwon National University Department of Mechanical Engineering Pohang Univer sity of Science and Technology

The design and fabrication processes of a novel scanner with minimized coupling motions for a high-speed atomic force microscope （AFM） were addressed. An appropriate design modification was proposed through the analyses of the dynamic characteristics of existing linear motion stages using a dynamic analysis program, Recurdyn. Because the scanning speed of each direction may differ, the linear motion stage for a high-speed scanner was designed to have different resonance frequencies for the modes, with one dominant displacement in the desired directions. This objective was achieved by using one-direction flexure mechanisms for each direction and mounting one stage for fast motion on the other stage for slow motion. This unsymmetrical configuration separated the frequencies of two vibration modes with one dominant displacement in each desired direction, and hence suppressed the coupling between motions in two directions. A pair of actuators was used for each axis to decrease the crosstalk between the two motions and give a sufficient force to actuate the slow motion stage, which carried the fast motion stage, A lossy material, such as grease, was inserted into the flexure hinge to suppress vibration problems that occurred when using an input triangular waveforrn. With these design modifications and the vibration suppression method, a novel scanner with a scanning speed greater than 20 Hz is achieved.

关键词： atomic force microscope scanner piezoelectric stack actuator crosstalk flexure hinge

Cutting force signal pattern recognition using hybrid neural network in end milling

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中国有色金属学会会刊：英文版 2009年第B9期19卷 209-214页

作者： Song-Tae seong Ko-Tae JO Young-moon LEE Research and Development Department Gyeongbuk Hybrid Technology Institute School of Mechanical Engineering Yeongnam University School of Mechanical Engineering Kyungpo ok National University

Under certain cutting conditions in end milling, the signs of cutting forces change from positive to negative during a revolution of the tool. The change of force direction causes the cutting dynamics to be unstable which results in chatter vibration. Therefore, cutting force signal monitoring and classification are needed to determine the optimal cutting conditions and to improve the efficiency of cut. Artificial neural networks are powerful tools for solving highly complex and nonlinear problems. It can be divided into supervised and unsupervised learning machines based on the availability of a teacher. Hybrid neural network was introduced with both of functions of multilayer perceptron (MLP) trained with the back-propagation algorithm for monitoring and detecting abnormal state, and self organizing feature map (SOFM) for treating huge datum such as image processing and pattern recognition, for predicting and classifying cutting force signal patterns simultaneously. The validity of the results is verified with cutting experiments and simulation tests.

关键词：切削力信号混合神经网络模式识别铣床人工神经网络切削条件信号监测监督学习

Meso-porous silicon-coated carbon nanotube as an anode for lithium-ion battery

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Nano Research 2016年第7期9卷 2174-2181页

作者： won-Sik Kim Jonghyun Choi seong-Hyeon Hong Department of Materials Science and Engineering and Research Institute of Advanced Materials Seoul National University Seoul 151-744 Republic of Korea

Meso-porous Si-coated carbon nanotube （CNT） composite powders were prepared by combining a sol-gel method and the magnesiothermic reduction process. Meso-porous Si-coated CNT electrodes exhibit excellent cycle and rate performances as anodes in Li-ion batteries （LIBs）, which can be attributed to the efficient accommodation of volume change from meso-porous Si structure and the enhanced electrical conductivity from CNT core. This simple synthesis and subsequent reduction process provide a scalable route for the large-scale production of Si-C composite nanostructures, which can be utilized in a variety of applications, such as in photocatalysis, photoelectrochemical cells （PECs）, and LIBs.

关键词： meso-porous carbon nanotube (CNT) magnesiothermic reduction battery

A new strengthening mechanism driven by disruptive shear and solute segregation during warm rolling in 1.4 GPa class 12.5 wt% Al added-FeMnC ultra-lightweight steel

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Journal of Materials Science & Technology 2023年第26期157卷 174-188页

作者： Chiwon Kim Hyun-Uk Hong Joonoh moon Bong Ho Lee seong-Jun Park Chang-Hoon Lee Department of Materials Convergence and System Engineering Changwon National University 20 Changwondaehak-roChangwonGyeongnam 51140Republic of Korea Advanced Analysis Team Daegu Gyeongbuk Institute of Science and Technology 333 Technojungang-daeroDaegu42988Republic of Korea Ferrous Alloy Department Korea Institute of Materials Science 797 ChangwondaeroChangwonGyeongnam 51508Republic of Korea

Novel strengthening of Fe-29.1Mn-12.5Al-1.35C-4.95Cr steel achieved by warm rolling was *** solution-treated steel consisted of aγ-matrix containing nano-sizedκ-carbide((Fe,Mn)_(3) AlC)and elongated prior ferrite,which was transformed into FeAl-type B2 and Fe_(3) Al-type D0_(3) *** solution-treated steel exhibited poor strain hardening owing to glide softening associated withκ-carbide shearing by ***,after warm rolling with a reduction ratio of 30%at 300℃,the yield and tensile strengths significantly increased from 917 to 1300 MPa and 1025 to 1419 MPa,*** tensile test conducted at 300℃to simulate warm rolling exhibited serrated flows,indicating dy-namic strain aging(DSA).Atom probe tomography exhibited that the C atoms inκ-carbide were swept away along the slip direction by disruptive shear during rolling at 300℃.The swept C atoms along the slip direction interacted strongly with dislocations at 300℃,with repeated pinning and breakaway of dislocations from the C *** contributed to significant strengthening owing to the formation of a solute-rich atmosphere after warm *** results of the tensile tests at 300℃indicated that the de-gree of strengthening was proportional to the pre-strain *** strength of 1.4 GPa can be achieved with good ductility(17%elongation)by warm *** novel warm-rolling strengthening method ex-pedites the potential application of Fe-29.1Mn-12.5Al-1.35C-4.95Cr as a 1.4 GPa class ultra-lightweight steel.

关键词： FeMnAlC Cr addition κ-carbide Dynamic strain aging Strengthening

Surgical Repair of Ventricular Septal Defect in Neonates: Indications and Outcomes

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Congenital Heart Disease 2024年第1期19卷 69-83页

作者： Jae Hong Lee Sungkyu Cho Jae Gun Kwak Hye won Kwon Woong-Han Kim Mi Kyoung Song Sang-Yun Lee Gi Beom Kim Eun Jung Bae Department of Thoracic and Cardiovascular Surgery Research Institute for Convergence of Biomedical Science and TechnologyPusan National University Yangsan HospitalYangsanKorea Department of Thoracic and Cardiovascular Surgery Seoul National University Children’s HospitalSeoulKorea Department of Pediatrics Seoul National University Children’s HospitalSeoulKorea

Background:The optimal surgical timing and clinical outcomes of ventricular septal defect(VSD)closure in neo-nates remain *** aimed to evaluate the clinical outcomes of VSD closure in neonates(age≤30 days).Methods:We retrospectively reviewed 50 consecutive neonates who underwent VSD closure for isolated VSDs between August 2003 and June *** for the procedure included congestive heart failure/failure to thrive and pulmonary *** adverse events(MAEs)were deﬁned as the composite of all-cause mortality,reoperation,persistent atrioventricular block,and signiﬁcant(≥grade 2)valvular ***:The median age and body weight at operation were 26.0 days(interquartile range[IQR],18.8–28.3)and 3.7 kg(IQR,3.3–4.2),*** median follow-up duration was 110.4 months(IQR,56.8–165.0).Seven patients required preoperative respiratory support,andﬁve had signiﬁcant(≥grade 2)preoperative valvular *** early mortality occurred due to irreversible cardiogenic shock;no late mortality was *** reopera-tion was due to hemodynamically signiﬁcant residual VSD at 103.8 months *** overall survival,freedom from reoperation,and freedom from MAE at 15-years were 98.0%,96.3%,and 94.4%,***-operative mechanical ventilation was associated with a longer duration of postoperative mechanical ventilation(p<0.001)and a longer length of intensive care unit stay(p<0.001).Conclusions:VSD closure with favorable outcomes without morbidities is feasible even in ***,neonates requiring preoperative respiratory support may require careful postoperative management considering the long-term postoperative ***,surgical VSD closure might be indicated earlier in neonates with respiratory compromise.

关键词： Ventricular septal defect neonate early surgery neonatal surgery

Varifocal occlusion in an optical see-through near-eye display with a single phase-only liquid crystal on silicon

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Photonics Research 2024年第4期12卷 833-853页

作者： WOONGSEOB HAN JAE-won LEE JUNG-YEOP SHIN MYEONG-HO CHOI HAK-RIN KIM JAE-HYEUNG PARK Department of Electrical and Computer Engineering Inha University100 Inha-roMichuhol-guIncheon 22212Republic of Korea School of Electronic and Electrical Engineering Kyungpook National University80 Daehak-roBuk-guDaegu 41566Republic of Korea School of Electronics Engineering Kyungpook National University80 Daehak-roBuk-guDaegu 41566Republic of Korea Department of Information and Communication Engineering Inha University100 Inha-roMichuhol-guIncheon 22212Republic of Korea

We propose a near-eye display optics system that supports three-dimensional mutual *** exploiting the polarization-control properties of a phase-only liquid crystal on silicon (LCoS),we achieve real see-through scene masking as well as virtual digital scene imaging using a single *** depth control of the real scene mask and virtual digital image is also achieved by using a focus tunable lens (FTL) pair of opposite *** proposed configuration using a single LCoS and opposite curvature FTL pair enables the self-alignment of the mask and image at an arbitrary depth without distorting the see-through view of the real *** verified the feasibility of the proposed optics using two optical benchtop setups:one with two off-the-shelf FTLs for continuous depth control,and the other with a single Pancharatnam–Berry phase-type FTL for the improved form factor.

关键词： optics crystal phase

Suggestion of advanced regression model on friction angle of fault gouge in South Korea

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Journal of Rock Mechanics and Geotechnical Engineering 2021年第6期13卷 1368-1379页

作者： seong-Woo moon Hyun-Seok Yun Yong-Seok Seo Department of Earth and Environmental Sciences Chungbuk National University1 Chungdae-roCheongju-siChungcheongbuk-do28644South Korea

Although friction characteristics of fault gouge are important to understand reactivation of fault,behavior of earthquake,and mechanism of slope failure,analysis results of fault gouge have low accuracy mostly than those of soils or rocks due to its high heterogeneity and low ***,to improve the accuracy of analysis results,we conducted simple regression analysis and structural equation model analysis and selected major influential factors of friction characteristics among many factors,and then we deduced advanced regression model with the highest coefficient of determination(R^(2)) via multiple regression *** most coefficients of determination in simple regression analysis are below0.3-0.4,coefficient of determination in multiple regression analysis is remarkably large as 0.657.

关键词： Fault gouge Friction angle Simple regression analysis Structural equation model analysis Multiple regression analysis

Long-term outcomes of endoscopic submucosal dissection for undifferentiated type early gastric cancer over 2 cm with R0 resection

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World Journal of Gastrointestinal Endoscopy 2024年第6期16卷 326-334页

作者： Jun Yong Bae Chang Beom Ryu moon Sung Lee Kulwinder S Dua Internal Medicine and Digestive Disease Center Seoul Medical CenterSeoul 02053South Korea Internal Medicine and Digestive Disease Center and Research Institute Soon Chun Hyang University of School of MedicineBucheon 14584South Korea Department of Medicine Medical College of WisconsinMilwaukeeWI 53226United States

BACKGROUND Endoscopic submucosal dissection(ESD)for over 2 cm in size undifferentiated type(UD type)early gastric cancer(EGC)confined to the mucosa is not only challenging,but also long-term outcomes are not well *** To evaluate the long-term outcomes of ESD done for UD type EGCs confined to the mucosa over 2 cm in size and compare the results with those where the lesions were less than 2 *** 143 patients with UD type EGC confirmed on histology after ESD at a tertiary hospital were *** with synchronous and metachronous lesions and a case with emergency surgery after ESD were excluded.A total of 137 cases were enrolled.79 cases who underwent R0 resection were divided into 2 cm or less(group A)and over 2 cm(group B)in *** Among 79 patients who underwent R0 resection,the number in group A and B were 51 and 28,*** mean follow-up period(SD)was 79.71±45.42 *** was a local recurrence in group A(1/51,2%)and group B(1/28,3.6%)*** patient in group A underwent surgery while the patient in group B underwent repeated ESD with no further recurrences in both *** was no regional lymph node metastasis,distant metastasis,and deaths in both *** R0 resection strategy for ESD on lesions over 2 cm,20.4%(28/137)of patients were able to avoid surgery compared with expanded *** If R0 resection is achieved by ESD,UD type EGCs over 2 cm also showed good and similar clinical outcomes as compared to lesions less than 2 cm when followed for over 5 *** R0 resection strategy,several patients can avoid surgery.

关键词： Undifferentiated type early gastric cancer Endoscopic submucosal dissection Long term outcomes Over 2 cm Early gastric cancer

Endoscopic ultrasonography does not differentiate neoplastic from non-neoplastic small gallbladder polyps

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World Journal of Gastroenterology 2009年第19期15卷 2361-2366页

作者： Young Koog Cheon won Young Cho Tae Hee Lee Young Deok Cho Jong Ho moon Joon seong Lee Chan Sup Shim Institute for Digestive Research and Digestive Disease Center Soon Chun Hyang University College of Medicine657 Hannam-DongYongsan-KuSeoul 140-743South Korea

AIM： To assess the ability of endoscopic ultrasonography （EUS） to differentiate neoplastic from non- neoplastic polypoid lesions of the gallbladder （PLGs）.METHODS： The uses of EUS and transabdominal ultrasonography （US） were retrospectively analyzed in 94 surgical cases of gallbladder polyps less than 20 mm in ***： The prevalence of neoplastic lesions with a diameter of 5-20 mm was 27.2% （10/58）; 22-15 mm, 25.4% （4/26）, and 16-20 mm, 50% （5/20）. The overall diagnostic accuracies of EUS and US for small PLGs were 80.9% and 63.9% （P 〈 0.05）, respectively. EUS correctly distinguished 12 （63.2%） of 19 neoplastic PLGs but was less accurate for polyps less than 1.0 cm （4/10, 40%） than for polyps greater than 1.0 cm （8/9, 88.9%）（P = 0.02）.CONCLUSION： Although EUS was more accurate than US, its accuracy for differentiating neoplastic from non-neoplastic PLGs less than 1.0 cm was low. Thus, EUS alone is not sufficient for determining a treatment strategy for PLGs of less than 1.0 cm.

关键词： Endoscopic ultrasonography Neoplasticlesion Polypoid gallbladder lesion