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A Finite Difference Scheme for Blow-Up Solutions of Nonlinear Wave Equations

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Numerical Mathematics(Theory,Methods and Applications) 2010年第4期3卷 475-498页

作者： Chien-Hong cho Research Institute for Mathematical Sciences Kyoto UniversityKyoto 606-8502Japan Department of Mathematics National Chung Cheng UniversityMin-HsiungChia-Yi 621Taiwan

We consider a finite difference scheme for a nonlinear wave equation, whose solutions may lose their smoothness in finite time, i.e., blow up in finite time. In order to numerically reproduce blow-up solutions, we propose a rule for a time-stepping,which is a variant of what was successfully used in the case of nonlinear parabolic equations. A numerical blow-up time is defined and is proved to converge, under a certain hypothesis, to the real blow-up time as the grid size tends to zero.

关键词： Finite difference method nonlinear wave equation blow-up

AN APPROACH TO ANALYSIS OF SINGLE PIER BASED ON THE VARIATIONAL PRINCIPLE IN MULTI-LAYERED SOIL

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Acta Mechanica Solida Sinica 2001年第3期14卷 275-282页

作者： NG Shiu cho Department of Civil Enginddring The Hong Kong University of Science and TechnologyClearwaler BayHong Kong

In this study, a variational approach to the settlement analysisof an axially loaded pier em- bedded in a multi-layered soil profileis presented. In this method, the soil profile and the embedded pierare divided into a number of sub-layers according to the actualnumber o soil layers observed in the field. The displacement shapefunction of each soil layer is given as a product of an exponentialequation along the pier depth and the Bessel's solution in the radialdirection.

关键词： pier pile settlement

A method for automatically translating print books into electronic Braille books

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Science China(Information Sciences) 2016年第7期59卷 129-142页

作者： Taekeun PARK Jungil JUNG Jinsoo cho Department of Applied Computer Engineering Dankook University Department of IT Convergence Engineering Gachon University Department of Computer Engineering Gachon University

In this paper, a method for automatically translating scanned images from print books into electronic Braille books is proposed with the objective of reducing the amount of time and cost required for producing Braille books. The proposed method consists of processes for identifying character and image areas in a scanned image, automatically translating characters and images into Braille and tactile graphics, respectively, and positioning Braille and tactile graphics into an electronic Braille page. Experimental results show that the proposed method drastically reduces the time required to translate a print book into an electronic Braille book. Despite the drastic reduction in translation time, the method proposed in this paper does not compromise the ability to recognize information for the visually impaired compared to manually produced Braille books, demonstrating its feasibility in practical applications. Therefore, the proposed method is expected to significantly reduce the time and cost required for producing Braille books, and provide more reading materials for the visually impaired,making significant contributions to enhancing their knowledge and welfare.

关键词： Braille tactile graphic electronic Braille book automatic translation the visually impaired

Usefulness of magnifying endoscopy in post-endoscopic resection scar for early gastric neoplasm:A prospective short-term follow-up endoscopy study

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World Journal of Gastroenterology 2009年第3期15卷 349-355页

作者： Tae hoon Lee Il-Kwun Chung Ji-Young Park Chang Kyun Lee Suck-Ho Lee Hong Soo Kim Sang-Heum Park Sun-Joo Kim Hyun-Deuk cho Young Hwangbo Division of Gastroenterology Department of Internal MedicineSoonchunhyang University College of MedicineCheonan Hospital23-20 Bongmyung-dongCheonan330-721South Korea Department of Pathology Soonchunhyang University College of MedicineCheonan Hospital23-20 Bongmyung-dongCheonan330-721South Korea Department of Preventive Medicine Soonchunhyang University College of MedicineCheonan Hospital23-20 Bongmyung-dongCheonan330-721South Korea

AIM： To investigate the relationship between postendoscopic resection （ER） scars on magnifying endoscopy （ME） and the pathological diagnosis in order to validate the clinical significance of ME. METHODS： From January, 2007 to June, 2008, 124 patients with 129 post-ER scar lesions were enrolled. Mucosal pit patterns on ME were compared with conventional endoscopy （CE） findings and histological results obtained from targeted biopsies. RESULTS： CE findings showed nodular scars （53/129）, erythematous scars （85/129）, and ulcerative scars （4/129）. The post-ER scars were classified into four pit patterns of sulci and ridges on ME：（ Ⅰ ） 47 round; （Ⅱ） 54 short rod or tubular; （Ⅲ） 19 branched or gyrus-like;and （Ⅳ） 9 destroyed pits. Sensitivity and specificity were 88.9% and 62.5%, respectively, by the presence of nodularity on CE. Erythematous lesions were high sensitivity （100%）, but specificity was as low as 36.7%. The range of the positive predictive va ue （PPV） on CE was as low as 10.6%-25%. Nine type N pit patterns were diagnosed as tumor lesions, and 120 cases of type Ⅰ-Ⅲ pit patterns revealed non-neoplastic lesions. Thus, the sensitivity, specificity, and the PPV of ME were 100%. CONCLUSION： ME findings can detect the presence of tumor in post-ER scar lesions, and make evident the biopsy target site in short-term follow-up. Further large-scale and long-term studies are needed to determine whether ME can replace endoscopic biopsy.

关键词： Endoscopic mucosal resection Endoscopic submucosal dissection Magnifying endoscopy Pitpattern Scar

Mechanical behavior and properties of fiber reinforced ceramic matrix composites for high temperature use

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航空动力学报 2007年第4期22卷 594-601页

作者： chongdu cho Qiang Pan Sangkyo Lee Department of Mechanical Engineering Inha University Mechanical Engineering Graduate School Inha University

Ceramics can keep their mechanical characteristics up to 2 000℃ or *** this paper,A model to predict ultimate strength of continuous fiber-reinforced brittle matrix composites is developed.A statistical theory for the strength of a uni-axially fiber-reinforced brittle matrix composite is *** a semi-empirical frictional heating method for estimating in-situ interfacial shear in fiber-reinforced ceramic matrix composites was *** uneven fiber packing variation as well as uneven micro-damage during fatigue can be expected to have effects on the composites:generation of frictional heating,thermal gradients,and residual stresses around local fiber *** study examined those engineering interests by the finite element method.

关键词：高温纤维增强型陶瓷基复合材料机械性能有限元航空推进系统

Electrochemical Characteristics in Seawater for Cold Thermal Spray-Coated Al-Mg Alloy Layer

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Acta Metallurgica Sinica(English Letters) 2016年第8期29卷 727-734页

作者： Il-cho Park Seong-Jong Kim Division of Marine Engineering Mokpo National Maritime University

For corrosion protection of carbon steel in a marine environment,cold arc thermal spray coating was applied to the surface with Al and Al-Mg alloy *** surface hardness of Al and Al-Mg thermal spray coatings increased with Mg *** the various electrochemical experiments were carried out to evaluate corrosion damage characteristics of the thermal spray coating *** Al and Al-Mg thermal spray coating layers presented negative potentials compared to carbon steel in corrosion potential *** an anodic polarization experiment revealed a tendency of activation polarization with no ***,the corrosion damage of the thermal spray coating layer in galvanostatic experiment was observed mainly at the defect area,and the Al-3Mg thermal spray coating layer presented less surface damages than *** addition,the Al-3Mg thermal spray coating layer showed the lowest corrosion rate while having a sufficient driving voltage for cathodic corrosion ***,it is an optimal thermal spray material for sacrificial anode.

关键词： Corrosion protection Carbon steel Arc thermal spray coating Al-Mg alloy Marine environment

Importance of nutrient availability for soluble microbial products formation during a famine period of activated sludge:Evidence from multiple analyses

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Journal of Environmental Sciences 2019年第10期31卷 112-121页

作者： Tahir Maqbool Jinwoo cho Jin Hur Department of Environment and Energy Sejong University

Much remains unknown about compositional variations in soluble microbial products(SMP)with the shift of the substrate condition from a feast to a famine phase in biological treatment *** study demonstrated that the formation of SMP could be suppressed by up to 75%during the famine phase with the addition of essential *** contrast,presence of electron acceptor did not play any significant role during the stress condition,showing the similar amounts of SMP(r=0.98,p0.95).The fluorescence excitation-emission matrix coupled with parallel factor analysis(EEM-PARAFAC)revealed the presence of four different fluorescent components,including two protein-like(C1 and C4),fulvic-like(C2),and humic-like(C3)components,in the SMP and bEPS formed at different *** C1 and C4 showed increasing trends(R^2>0.95)with the length of starvation in the bioreactors without essential *** availability was found to be a key factor to quench the production of large-sized *** study provides a wealth of information on operation conditions of activated sludge treatment systems to minimize large sized SMP molecules(particularly proteins),which typically exert many environmental concerns to effluent organic matter quality.

关键词： Soluble microbial products Nutrient availability EEM-PARAFAC SEC-OCD-OND Famine phase

Strong internal resonance in a nonlinear, asymmetric microbeam resonator

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Microsystems & Nanoengineering 2021年第1期7卷 117-131页

作者： Keivan Asadi Junghoon Yeom Hanna cho Department of Mechanical and Aerospace Engineering The Ohio State UniversityColumbusOH 43210USA Department of Mechanical Engineering Michigan State UniversityEast LansingMI 48824USA

Exploiting nonlinear characteristics in micro/nanosystems has been a subject of increasing interest in the last *** others,vigorous intermodal coupling through internal resonance(IR)has drawn much attention because it can suggest new strategies to steer energy within a micro/nanomechanical ***,a challenge in utilizing IR in practical applications is imposing the required frequency commensurability between vibrational modes of a nonlinear micro/***,we experimentally and analytically investigate the 1:2 and 2:1 IR in a clamped–clamped beam resonator to provide insights into the detailed mechanism of *** is demonstrated that the intermodal coupling between the second and third flexural modes in an asymmetric structure(e.g.,nonprismatic beam)provides an optimal condition to easily implement a strong IR with high energy transfer to the internally resonated *** this case,the quadratic coupling between these flexural modes,originating from the stretching effect,is the dominant nonlinear mechanism over other types of geometric *** design strategies proposed in this paper can be integrated into a typical micro/nanoelectromechanical system(M/NEMS)via a simple modification of the geometric parameters of resonators,and thus,we expect this study to stimulate further research and boost paradigm-shifting applications exploring the various benefits of IR in micro/nanosystems.

关键词： nonlinear asymmetric clamped

Cerebral and pulmonary embolisms after transcatheter arterial chemoembolization for hepatocellular carcinoma

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World Journal of Gastroenterology 2008年第30期14卷 4834-4837页

作者： Chang Soo choi Ki hoon Kim Geom Seog Seo Eun Young cho Hyo Jeong Oh Suck Chei choi Tae Hyeon Kim Haak Cheoul Kim Byung Suk Roh Department of Internal Medicine and Digestive Disease Research Institute Wonkwang University School of Medicine Department of Radiology Wonkwang University School of Medicine

A cerebral lipiodol embolism is an extremely rare complication of transcatheter arterial chemoembolization for hepatocellular carcinoma. We present a case of cerebral lipiodol embolism that occurred after the third ar... 详细信息

关键词： Transcatheter arterial chemoembolization Cerebral embolism Complication Hepatocellular carcinoma Lipiodol