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A DIFFUSION–TRANSPORT hYBRID METhOD FOR ACCELERATING OPTICAL TOMOGRAPhY

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Journal of Innovative Optical health Sciences 2010年第4期3卷 293-305页

作者： hYUN KEOL kim ANDREAS h.hIELSChER Department of Biomedical Engineering Columbia University New YorkNY 10027USA Department of Radiology Columbia University New YorkNY 10032USA Department of Electrical Engineering Columbia University New YorkNY 10027USA

It is well acknowledged that the equation of radiative transfer(ERT)provides an accurate prediction of light propagation in biological tissues,while the diffusion approximation(DA)is of limited accuracy for the transport ***,ERT-based reconstruction codes require much longer computation times as compared to DA-based reconstruction *** introduce here a computationally efficient algorithm,called a diffusion–transport hybrid solver,that makes use of the DA-or low-order ERT-based inverse solution as an initial guess for the full ERT-based reconstruction *** evaluate the performance of this hybrid method,we present extensive studies involving numerical tissue phantoms and experimental *** a result,we show that the hybrid method reduces the reconstruction time by a factor of up to 23,depending on the physical character of the problem.

关键词： Optical tomography reconstruction time radiative transfer equation

Development of mathematical model with a genetic algorithm for automatic arc welding process

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Acta Metallurgica Sinica(English Letters) 2010年第3期23卷 230-240页

作者： D.T.Thao I.S.kim J.W.Jeong J.h.Lee J.Y.Shim h.h.kim Department of Mechanical Engineering Mokpo National University

This paper is to represent new algorithms to predict process parameters on top-bead width in robotic gas metal arc（GMA） welding *** models have been developed：linear, curvilinear and intelligent model based on full factorial design with two *** analysis was employed for optimization of the coefficients of linear and curvilinear models, while genetic algorithm（GA） was utilized to estimate the coefficients of an intelligent *** only the fitting of these models were checked and compared by using a variance test（ANOVA）, but also the prediction on top-bead width using the developed models were carried out based on the additional *** developed models were employed to investigate the characteristic between process parameters and top-bead *** solutions and graphical representation showed that the intelligent model developed can be employed for prediction of bead geometry in GMA welding process.

关键词： Top-bead width Genetic algorithm Multiple regression Robotic arc welding GMA welding

Development of a 3D subcutaneous construct containing insulin-producing beta cells using bioprinting

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Bio-Design and Manufacturing 2022年第2期5卷 265-276页

作者： Chi B.Ahn Ji-hyun Lee Joo h.kim Tae h.kim hee-Sook Jun Kuk h.Son Jin W.Lee Department of Molecular Medicine College of MedicineGachon University155Gaetbeol-roYeonsu-kuIncheonRepublic of Korea Department of health Sciences and Technology GAIHSTGachon University155Gaetbeol-roYeonsu-kuIncheonRepublic of Korea College of Pharmacy Gachon University191Hambangmoe-roYeonsu-kuIncheonRepublic of Korea Department Thoracic and Cardiovascular Surgery Gachon University Gil Medical CenterCollege of MedicineGachon University21Namdong-daero 774 beon-gilNamdong-guIncheonRepublic of Korea

Type 1 diabetes is caused by insulin deficiency due to the loss of beta cells in the islets of *** severe cases,islet transplantation into the portal vein is ***,due to the loss of transplanted islets and the failure of islet function,the 5-year insulin independence rate of these patients ishis study,we developed a long-term,insulin-secreting,3 Dbioprinted construct implanted subcutaneously with the aim of preventing islet *** bioprinted construct was fabricated by the multi-layer bioprinting of beta-cell(mouse insulinoma-6:MIN-6)-encapsulated alginate bioink and poly(caprolactone)biodegradable polymer.A glucose response assay revealed that the bioprinted constructs proliferated and released insulin normally during the 4-week in vitro *** MIN-6 generated clusters with a diameter of 100-200μm,similar to the original pancreatic islets in the *** an in vivo study using type 1 diabetes mice,animals implanted with bioprinted constructs showed three times higher insulin secretion and controlled glucose levels at 8 weeks after *** the implanted,bioprinted constructs had a positive effect on insulin secretion in the experimental animals,the survival rate of the implanted group(75%)was three times higher than that of the non-implanted group(25%).The results suggest that the proposed,3 D-bioprinted,subcutaneous construct can be a better alternative to portal vein islet transplantation.

关键词： 3D bioprinting Subcutaneous construct Type 1 diabetes Insulin Beta cells

Identification of the Amplification Mechanism in the First Free-Electron Laser as Net Stimulated Free-Electron Two-Quantum Stark Emission

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Chinese Physics Letters 2009年第5期26卷 86-89页

作者： S. h. kim 6300 Roundrock Trail 4203 Plano Texas 75023 USA

We find that the electron phase with respect to the incident laser radiation must be random in the first freeelectron laser （FEL） and, hence, the incident laser radiation works as a relaxation force to keep a Maxwellian distribution. We formulate the threshold laser intensity for amplification which agrees with the measured value in the order of magnitude in the first FEL. The magnetic wiggler must produce an electric wiggler whose period is the same as that of the magnetic wiggler. We find that net stimulated free-electron two-quantum Stark （FETQS） emission driven by this electric wiggler is the mechanism responsible for the measured gain and the measured laser intensity at the plateau in the first FEL.

关键词： gamma-ray bursts gamma-rays relativity

Computational study on influence of RF shielding box on inductance of coil

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Plasma Science and Technology 2019年第6期21卷 23-28页

作者： S J kim J J LEE Y S LEE J h kim S J YOU Applied Physics lab for PLasma Engineering(APPLE) Department of Physics Chungnam National University Daejeon 34134 Republic of Korea Korea Research Institute of Standards and Science(KRISS) Daejeon 34113 Republic of Korea

Despite the fact that a radio frequency (RF) shielding box affects a coil inductance used in matching network,RF engineers have used a coil inductance measured in open space on designing matching networks since it is difficult to precisely measure the coil inductance within the RF shielding *** this work,we investigate the influences of the RF shielding box on the coil inductance via a 3D full electromagnetic wave *** results shows that the coil inductance decreases from-6.0% to-11.9% compared with its ideal inductance depending on coil positions within the RF shielding *** inductive and capacitive coupling between the coil and surfaces of the RF shielding box contribute to the reduction of the coil *** expect that these results would be useful for those who design RF matching networks.

关键词： 3D full EM wave simulation RF matching component RF shield inductive and capacitive coupling

What Causes the Springtime Tropospheric Ozone Maximum over Northeast Asia?

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Advances in Atmospheric Sciences 2010年第3期27卷 543-551页

作者： Jae h.kim hyunjin LEE Department of Atmospheric Science Pusan National University

Scientists have long debated the relative importance of tropospheric photochemical production versus stratospheric influx as causes of the springtime tropospheric ozone maximum over northern mid-latitudes. This paper investigates whether or not stratospheric intrusion and photochemistry play a significant role in the springtime ozone maximum over Northeast Asia, where ozone measurements are sparse. We examine how tropospheric ozone seasonalities over Naha （26°N, 128°E）, Kagoshima （31°N, 131°E）, and Pohang （36°N, 129°E）, which are located on the same meridional line, are related to the timing and location of the jet stream. The ozone seasonality shows a gradual increase from January to the maximum ozone month, which corresponds to April at Naha, May at Kagoshima, and June at Pohang. In order to examine the occurrence of stratospheric intrusion, we analyze a correlation between jet stream activity and tropospheric ozone seasonality. From these analyses, we did not find any favorable evidence supporting the hypothesis that the springtime enhancement may result from stratospheric intrusion. According to trajectory analysis for vertical and horizontal origins of the airmass, a gradual increasing tendency in ozone amounts from January until the onset of monsoon was similar to the increasing ozone formation tendency from winter to spring over China's Mainland, which has been observed during the build-up of tropospheric ozone over Central Europe in the winter-spring transition period due to photochemistry. Overall, the analyses suggest that photochemistry is the most important contributor to observed ozone seasonality over Northeast Asia.

关键词： tropospheric ozone photochemistry, stratospheric intrusion, jet stream activity, trajectory

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Journal of Central South University 2009年第5期16卷 789-793页

作者： kim J h LEE S h 王洪梅 School of Mechatronics Changwon National University 9 Sarim-dong Changwon Gyeongnam 641-773 Korea

Fault detection technique is introduced with similarity measure. The characteristics of conventional similarity measure based on fuzzy number are discussed. With the help of distance measure, similarity measure is constructed explicitly. The designed distance-based similarity measure is applicable to general fuzzy membership functions including non-convex fuzzy membership function, whereas fuzzy number-based similarity measure has limitation to calculate the similarity of general fuzzy membership functions. The applicability of the proposed similarity measure to general fuzzy membership structures is proven by identifying the definition. To decide fault detection of flight system, the experimental data （pitching moment coefficients and lift coefficients） are transformed into fuzzy membership functions. Distance-based similarity measure is applied to the obtained fuzzy membership functions, and similarity computation and analysis are obtained with the fault and normal operation coefficients.

关键词： similarity measure fuzzy number, distance non-convex membership function

Deformation heterogeneity of Ti under cryogenic channel-die compression

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Progress in Natural Science:Materials International 2011年第4期21卷 277-285页

作者： K.h.kim S.K.hWANG Division of Materials Science and Engineering Inha University

Commercial purity Ti was subjected to channel die compression in liquid nitrogen for the purpose of studying its deformation characteristics from the viewpoint of the grain refinement induced by severe plastic *** specimens showed microstructural heterogeneity in that the initial blocky grains of about 50 urn in size turned into a mixture of the easily deforming soft grains and the hard grains revealing local concentration of dislocations and deformation *** electron back scattered diffraction analysis the in-grain misorientation-axis distribution was studied,from which it was found that the deformation heterogeneity resulted from the anisotropy of individual grains with respect to the compression die:while the soft grains were those oriented favorably for the prismslip,the hard ones were oriented for non-prism slips and deformation *** difference in the response of individual grains,therefore,led to a remarkable effect of the crystal texture of specimens on the maximum strain that can be imposed on specimens without *** on the present results,a way to achieve expedient grain refinement through the cryogenic plane-strain compression was suggested.

关键词： titanium cryogenic deformation texture microstructure

Advancement in materials for energy-saving lighting devices

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Frontiers of Chemical Science and Engineering 2012年第1期6卷 13-26页

作者： Tak h.kim Wentai WANG Qin LI Department of Chemical Engineering Curtin UniversityPerth 6845Australia

This review provides a comprehensive account of energy efficient lighting devices, their working principles and the advancement of these materials as an underpinning to the development of technology. Particular attention has been given to solid state lighting devices and their applications since they have attracted the most interest and are the most promising. Solid state lighting devices including white light emitting diodes （LEDs）, organic LEDs （OLEDs）, quantum-dot LEDs （QLEDs） and carbon-dot LEDs （CLEDs） are promising energy efficient lighting sources for displays and general lighting. however there is no universal solution that will give better performance and efficiency for all types of applications. LEDs are replacing traditional lamp,; for both general lighting and display applications, whereas OLEDs are finding their own special application,; in various areas. QLEDs and CLEDs have advantages such as high quantum yields, narrow emission spectra, tunable emission spectra and good stability over OLEDs, so applications for these devices are being extended to new types of lighting sources. There is a great dean of research on these materials and their processing technologies and the commercial viability of these technologies appears strong.

关键词： energy-saving lighting devices solid statelighting devices