198 results on '"Kim, S. S."'
Search Results
2. Gyro-averaging operators with magnetic field inhomogeneity.
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Jhang, Hogun and Kim, S. S.
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MAGNETIC fields , *PADE approximant , *BESSEL functions , *WAVENUMBER - Abstract
We derive expressions for the gyro-averaging operator that is applicable to electrostatic fluctuations in a spatially inhomogeneous magnetic field. Both low and high wavenumber limits are considered. The gyro-averaging operator for the former case is represented by sums of Bessel functions with different orders. A simplified expression is provided as a Padé approximant in the low wavenumber limit. This form could be used in practical computations based on the gyrofluid formulation. In the high wavenumber limit, we find that the operator naturally involves fractional derivatives whose physical interpretations are yet to be explored. Discussions are made of a potential impact of this asymptotic expression in the high wavenumber limit. [ABSTRACT FROM AUTHOR]
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- 2022
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3. Body composition assessment in patients who underwent pancreatoduodenectomy: a comparative study of bioelectrical impedance analysis and CT scan imaging.
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Kim, J., Kim, S.-s., Hwang, H.K., Kang, C.M., Kim, K.S., and Kim, S.H.
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- 2024
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4. Inactivation of Escherichia coli, Salmonella enterica serovar Typhimurium, and Bacillus cereus in roasted grain powder by radio frequency heating.
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Jeong, K.-O., Kim, S.-S., Park, S.-H., and Kang, D.-H.
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SALMONELLA enterica serovar typhimurium , *RADIO frequency , *BACILLUS cereus , *ESCHERICHIA coli , *SALMONELLA enterica , *SALMONELLA typhimurium - Abstract
Aims: The objective of this study was to evaluate the antimicrobial effects of radio frequency (RF) heating and the combination treatment of RF heating with ultraviolet (UV) radiation against foodborne pathogens in roasted grain powder (RGP). Methods and Results: Foodborne pathogens inoculated on RGP were subjected to RF heating or RF-UV combination treatments. After 120 s of RF heating, 4•68, 3•89 and 4•54 log reductions were observed for Escherichia coli, Salmonella Typhimurium and Bacillus cereus vegetative cells respectively. The combined RF-UV treatment showed synergistic effects of over 1 log unit compared to the sum of individual treatment for E. coli and S. Typhimurium, but not for B. cereus vegetative cells because of their high UV resistance. Germinated B. cereus cells were not significantly inactivated by RF heating (<1 log CFU per gram), and increased heat resistance compared to the vegetative cells was verified with mild heat treatment. The colour of RGP was not significantly affected by the RF or RF-UV treatments. Conclusions: Applying RF heating to grain-based food products has advantages for the inactivation of E. coli and S. Typhimurium in RGP. Significance and Impact of the Study: The results of the present study could be used as a basis for determining the treatment conditions for inactivating E. coli and other foodborne pathogens such as S. Typhimurium and B. cereus in RGP. [ABSTRACT FROM AUTHOR]
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- 2020
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5. Vorticity generation by finite Larmor radius effects from heat source and sink.
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Kim, S. S. and Hogun Jhang
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HEAT sinks , *LARMOR radius , *VORTEX motion , *SHEAR flow , *PLASMA turbulence , *PLASMA dynamics , *PHASE space - Abstract
We investigate the finite Larmor radius (FLR) effects that are associated with an external heat source or a sink in the full-f formulation of plasma dynamics. Specifically, we show that a gyrocenter or an additional vorticity source due to the FLR effect should be replenished in fullf turbulence simulations. A quantitative energetics analysis in particle phase space demonstrates that an additional vorticity source is required to satisfy the total energy conservation. A physics picture is presented to elucidate the mechanism of the vorticity source generation from the FLR effects of a heat source or a sink, which reproduces the main result obtained from the quantitative analysis. The additional vorticity source is expected to considerably enhance the generation of the radial electric field and subsequent E × B flow shear in the off-axis heating case. [ABSTRACT FROM AUTHOR]
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- 2020
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6. A conservative gyrofluid model: Effect of closure on energetics.
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Kim, S. S. and Jhang, Hogun
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PLASMA turbulence , *LARMOR radius , *FUSION reactors - Abstract
We develop a conservative gyrofluid model that is suitable for global flux-driven simulations of electrostatic tokamak plasma turbulence. On the basis of the general gyrofluid moment equations, we derive energy equations which enable us to manipulate the impact of a gyrofluid closure on energetics. We demonstrate that an artificial manipulation of high order moment contributions to gyrofluid moment equations via a closure model can lead to the violation of the energy conservation. A fluid closure is also found to restrict the maximum attainable order of finite Larmor radius terms, implying the loss of dynamical information by the closure. [ABSTRACT FROM AUTHOR]
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- 2020
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7. Pneumothorax, pneumoperitoneum and aspiration pneumonia during peroral endoscopic myotomy.
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Kim, S. S., Choi, H. H., Sin, S. H., Kim, H. K., and Kim, S. W.
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ASPIRATION pneumonia , *MYOTOMY , *PNEUMOPERITONEUM , *PNEUMOTHORAX , *ESOPHAGEAL achalasia - Abstract
This article, published in the journal Endoscopy, discusses a case of unusual complications during peroral endoscopic myotomy (POEM) in a 17-year-old female with a history of dysphagia and type II achalasia. The patient experienced regurgitation and aspiration during the procedure due to extensive tissue adhesions, leading to pneumothorax, pneumoperitoneum, and multiple perforations. Immediate intervention was taken, including thoracic drainage and hemostatic clip closure. The patient also developed multifocal pneumonia, which was treated with antibiotics. After one week, the patient showed recovery and was discharged after two weeks with significant improvement. [Extracted from the article]
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- 2024
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8. Flux-driven nonlinear fluid simulations of ion thermal confinement change by external torque.
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Jhang, Hogun and Kim, S. S.
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TORQUE , *SHEAR flow , *ION temperature , *VORTEX motion , *COMPRESSIBILITY , *IONS - Abstract
From nonlinear flux-driven fluid simulations, we show that the external torque has a profound influence on ion thermal confinement. A key parameter controlling the confinement change is found to be the ratio of the net external torque to the applied power input. For a given value of external torque, the ion temperature profile destiffening and the corresponding confinement enhancement occur when the ratio is below a threshold value. This confinement improvement is shown to originate from the increase in the zonal flow shearing rate due to the conversion of parallel flow compressibility to zonal vorticity. Confinement degradation and the restoration of profile stiffness arise beyond the critical value of the ratio due to the onset of the parallel velocity gradient instability. This result implies the existence of an optimal torque value for the given heating power to maximize the thermal confinement. [ABSTRACT FROM AUTHOR]
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- 2019
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9. Antimicrobial-resistant Enterobacteriaceae recovered from companion animal and livestock environments.
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Adams, R. J., Kim, S. S., Mollenkopf, D. F., Mathys, D. A., Schuenemann, G. M., Daniels, J. B., and Wittum, T. E.
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ENTEROBACTERIACEAE diseases , *BETA lactamases , *VETERINARY medicine , *CARBAPENEMASE , *FLUOROQUINOLONES - Abstract
Antimicrobial-resistant bacteria represent an important concern impacting both veterinary medicine and public health. The rising prevalence of extended-spectrum beta-lactamase (ESBL), AmpC beta-lactamase, carbapenemase (CRE) and fluoroquinolone-resistant Enterobacteriaceae continually decreases the efficiency of clinically important antibiotics. Moreover, the potential for zoonotic transmission of antibiotic-resistant enteric bacteria increases the risk to public health. Our objective was to estimate the prevalence of specific antibiotic-resistant bacteria on human contact surfaces in various animal environments. Environmental surface samples were collected from companion animal shelters, private equine facilities, dairy farms, livestock auction markets and livestock areas of county fairs using electrostatic cloths. Samples were screened for Enterobacteriaceae expressing AmpC, ESBL, CRE or fluoroquinolone resistance using selective media. Livestock auction markets and county fairs had higher levels of bacteria expressing both cephalosporin and fluoroquinolone resistance than did equine, dairy, and companion animal environments. Equine facilities harboured more bacteria expressing cephalosporin resistance than companion animal shelters, but less fluoroquinolone resistance. The regular use of extended-spectrum cephalosporins in livestock populations could account for the increased levels of cephalosporin resistance in livestock environments compared to companion animal and equine facilities. Human surfaces, as well as shared human and animal surfaces, were contaminated with resistant bacteria regardless of species environment. Detecting these bacteria on common human contact surfaces suggests that the environment can serve as a reservoir for the zoonotic transmission of antibiotic-resistant bacteria and resistance genes. Identifying interventions to lower the prevalence of antibiotic-resistant bacteria in animal environments will protect both animal and public health. [ABSTRACT FROM AUTHOR]
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- 2018
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10. Ferroelectric properties of vanadium-doped Bi[sub 4]Ti[sub 3]O[sub 12] thin films deposited by a sol–gel method.
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Kim, S. S., Song, T. K., Kim, J. K., and Kim, Jinheung
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FERROELECTRICITY , *VANADIUM - Abstract
We report the enhancement of ferroelectric properties in vanadium-doped Bi[sub 4]Ti[sub 3]O[sub 12] (BIT) thin films deposited by a sol-gel method. Compared to the undoped BIT, V-doped BIT (BTV) showed higher polarizations and a better fatigue resistance as reported in ceramic systems recently [Noguchi et al., Appl. Phys. Lett. 78, 1903 (2001)]. BTV showed a remanent polarization (2P[sub r]) of 15.9 µC/cm², higher than the value for BIT, 12.5 µC/cm². The polarization of the BTV thin film capacitor decreased by 19%, while that of the BIT decreased by 23% after the fatigue test with 4 × 10[sup 10] switching cycles. [ABSTRACT FROM AUTHOR]
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- 2002
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11. IMPROVEMENT OF MICROWAVE ABSORBANCE OF POLYMER COMPOSITES OF W-TYPE HEXAFERRITE POWDERS BY ATTACHMENT OF FREQUENCY SELECTIVE SURFACE.
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CHO, H.-S. and KIM, S.-S.
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ELECTROMAGNETIC wave absorption , *POLYMERIC composites , *FREQUENCY selective surfaces , *FERRITES , *PERMEABILITY - Abstract
This work investigates the effect of a frequency selective surface (FSS) composed of a regular array of square loop elements on the absorption properties of grounded ferrite composites. Polymer matrix composites of CoZnW hexaferrite powders having small magnetic loss were used as the substrate material. Computational tools were used to model the interaction between electromagnetic waves and materials and determine the reflection coefficient. Reflection loss and bandwidth were greatly improved by attaching an FSS with controlled electrical resistance (R) onto the grounded ferrite composites. For the FSS with R = 800 Ω, the minimum reflection loss decreased to -25 dB at 10 GHz and the bandwidth was broadened to 7.5-12.5 GHz with respect to -10 dB reflection loss. [ABSTRACT FROM AUTHOR]
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- 2017
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12. EFFECT OF ELECTROLESS Ni-P PLATING ON THE BONDING STRENGTH OF Bi-Te-BASED THERMOELECTRIC MODULES.
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KIM, S. S., SON, I., and KIM, K. T.
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THERMOELECTRIC materials , *NICKEL-plating , *NICKEL phosphates , *CHEMICAL bonds , *BISMUTH telluride , *SOLDER & soldering - Abstract
In the present study, electroless Ni-P plating was applied to Bi-Te-based thermoelectric materials as a barrier layer and the effect of the Ni-P plating on the bonding strength of the thermoelectric module was investigated. The bonding strength of the n- and p-type modules increased after being subjected to the electroless Ni-P plating treatment. In the case of the thermoelectric module that was not subjected to electroless Ni-P plating, Sn and Te were interdiffused and formed a brittle Sn-Te-based metallic compound. The shearing mostly occurred on the bonding interface where such an intermetallic compound was formed. On the other hands, it was found from the FE-EPMA analysis of the bonding interface of thermoelectric module subjected to electroless Ni-P plating that the electroless Ni-P plating acted as an anti-diffusion layer, preventing the interdiffusion of Sn and Te. Therefore, by forming such an anti-diffusion layer on the surface of the Bi-Te based thermoelectric element, the bonding strength of the thermoelectric module could be increased. [ABSTRACT FROM AUTHOR]
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- 2017
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13. Precipitation of 3d transition-metal silicides in Czochralski silicon crystals.
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Wijaranakula, W. and Kim, S. S.
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SILICIDES , *SILICON crystals , *TRANSITION metals - Abstract
Focuses on a study which observed the precipitation of metal silicides in Czochralski silicon crystals contaminated with 3d transition metals. Background on 3d transition-metal silicides; Preparation of the crystals; Description of the crystal's growth.
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- 1994
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14. Surgical management of damaged inferior alveolar nerve caused by endodontic overfilling of calcium hydroxide paste.
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Byun, S.‐H., Kim, S.‐S., Chung, H.‐J., Lim, H.‐K., Hei, W.‐H., Woo, J.‐M., Kim, S.‐M., and Lee, J.‐H.
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ALVEOLAR nerve , *CALCIUM hydroxide , *ENDODONTICS , *DENTAL fillings , *FOREIGN body reaction , *SURGICAL decompression , *OSTEOTOMY , *VISUAL analog scale , *WOUNDS & injuries - Abstract
Aim To evaluate the neurosensory outcome of management of damaged inferior alveolar nerves caused by endodontic overfilling and to assess the efficacy of delayed surgical intervention. Methodology Nine patients who underwent surgical removal of extruded endodontic material were included. All patients were evaluated for neurosensory function using a set of standardized tests. The outcome of surgical intervention was evaluated through patient interview and quantitative statistical analysis. Results Surgical procedures included foreign body removal, microsurgical external/internal decompression, excision of neuroma followed by nerve repair, and excision of damaged nerve segment with interpositional nerve graft. Seven of the nine patients had significant improvement according to the follow-up neurosensory assessment. Four patients reported significant improvement, three patients reported mild improvement and two patients reported no appreciable improvement in the Visual Analog Scale ( VAS). Two patients who reported no appreciable improvement in VAS also did not achieve FSR. In these patients, calcium hydroxide was spread widely along the IAN and a surgical approach was obtained via sagittal spit osteotomy. The mean time to reach FSR was 222.7 (±41.8) days with a range of 106-397 days. In the early repair group who received surgery within 60 days, three out of five patients achieved FSR in a mean time of 198.0 (±76.2) days. The mean time to FSR in all four subjects who received surgical attention over 60 days after injury was 241.3 (±139.8) days with a range of 106-397 days. As all four cases in the late repair group with limited amount of nerve injury achieved FSR, only 3 of 5 early repair cases with wide-spread injury achieved a similar outcome. Conclusion The results of this case series confirmed the notion that surgical management of the inferior alveolar nerve is effective in the treatment of nerve injuries caused by endodontic extrusion of calcium hydroxide paste. Delayed surgical repair of the inferior alveolar nerve can be indicated and helpful for the neurosensory recovery of damaged IAN, however, the surgical management was less effective in case of widespread nerve injuries. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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15. Effects of resistivity on linear plasma responses to resonant magnetic perturbations in tokamak plasmas.
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Juhyung Kim, Kim, S. S., and Hogun Jhang
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TOKAMAKS , *MAGNETIC fields , *PLASMA gases , *QUANTUM perturbations , *MAGNETOHYDRODYNAMICS , *ELECTRON beams , *MATHEMATICAL models - Abstract
Numerical studies are made of the effects of resistivity on linear plasma responses to resonant magnetic perturbations (RMPs) in tokamaks based on a reduced magnetohydrodynamic model. From a local two-field model, it is suggested that the ratio of the poloidal electron advection to the resistivity diffusion rate αmαm can be a figure of merit parameter in linear RMP penetration physics. The shielding efficiency is governed by αm, and when αm ≳ 1, RMPs are effectively shielded. Global simulations using a four-field model [Hazeltine and Meiss, Phys. Rep. 121, 1 (1985)] show that there exists an effective threshold of the perpendicular electron flow (Ve,⊥c) beyond which RMPs cannot penetrate. Resistivity is found to determine Ve,⊥c which increases as resistivity becomes higher, making RMP penetration easier. At low resistivity, small Ve,⊥c renders the RMP penetration sensitive to ion collisionality and the change in q 95. The kink response is observed to be closely related to the residual level of RMPs at rational surfaces and can be also strongly affected by resistivity. [ABSTRACT FROM AUTHOR]
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- 2016
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16. Kinetic effects on geodesic acoustic modes and Stringer spin-up driven by a poloidally asymmetric particle source.
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Lee, Young-Hoon, Jhang, Hogun, Kim, S. S., and Lee, Jungpyo
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LANDAU damping , *GEODESICS , *WOOD pellets , *FUEL systems , *ACOUSTIC emission testing , *EMISSION control - Abstract
The impact of the poloidally inhomogeneous particle source on the onset of Stringer spin-up (SSU) and geodesic acoustic mode (GAM) is investigated. Using a gyrofluid model with Hammet–Perkins closure, it was found that Landau damping stabilizes both waves and subsequently makes a threshold. To capture the full effects of Landau damping, a gyrokinetic model is adopted and results are compared with those from the gyrofluid model. Both models predicted the same value of the threshold for SSU, while for the case of GAM, the gyrofluid model overestimates the threshold value. Considering maximal throughput of the ITER pellet fueling system, the source intensity is calculated at a similar or slightly lower level compared to the source threshold for SSU. [ABSTRACT FROM AUTHOR]
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- 2023
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17. Effect of milk fat content on the performance of ohmic heating for inactivation of Escherichia coli O157:H7, Salmonella enterica Serovar Typhimurium and Listeria monocytogenes.
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Kim, S.‐S. and Kang, D.‐H.
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MILKFAT , *RESISTANCE heating , *ESCHERICHIA coli , *SALMONELLA enterica serovar typhimurium , *LISTERIA monocytogenes , *BACTERIAL inactivation , *MILK microbiology - Abstract
Aims The effect of milk fat content on ohmic heating compared to conventional heating for inactivation of food-borne pathogens was investigated. Methods and Results Sterile cream was mixed with sterile buffered peptone water and adjusted to 0, 3, 7, 10% (w/v) milk fat content. These samples with varying fat content were subjected to ohmic and conventional heating. The effect of milk fat on temperature increase and electrical conductivity were investigated. Also, the protective effect of milk fat on the inactivation of foodborne pathogens was studied. For conventional heating, temperatures of samples increased with time and were not significantly ( P > 0·05) different regardless of fat content. Although the inactivation rate of Escherichia coli O157:H7, Salmonella Typhimurium and L. monocytogens decreased in samples of 10% fat content, a protective effect was not observed for conventional heating. In contrast with conventional heating, ohmic heating was significantly affected by milk fat content. Temperature increased more rapidly with lower fat content for ohmic heating due to higher electrical conductivity. Nonuniform heat generation of nonhomogeneous fat-containing samples was verified using a thermal infrared camera. Also, the protective effect of milk fat on E. coli O157:H7 and Listeria monocytogenes was observed in samples subjected to ohmic heating. Conclusions These results indicate that food-borne pathogens can survive in nonhomogeneous fat-containing foods subjected to ohmic heating. Therefore, more attention is needed regarding ohmic heating than conventional heating for pasteurizing fat-containing foods. Significance and Impact of the Study The importance of adequate pasteurization for high milk fat containing foods was identified. [ABSTRACT FROM AUTHOR]
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- 2015
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18. Flux-driven simulations of turbulence collapse.
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Park, G. Y., Kim, S. S., Hogun Jhang, Diamond, P. H., Rhee, T., and Xu, X. Q.
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COMPUTER simulation of turbulence , *OSCILLATIONS , *NONLINEAR theories , *TOKAMAKS , *FLUX (Energy) - Abstract
Using three-dimensional nonlinear simulations of tokamak turbulence, we show that an edge transport barrier (ETB) forms naturally once input power exceeds a threshold value. Profiles, turbulence-driven flows, and neoclassical coefficients are evolved self-consistently. A slow power ramp-up simulation shows that ETB transition is triggered by the turbulence-driven flows via an intermediate phase which involves coherent oscillation of turbulence intensity and E×B flow shear. A novel observation of the evolution is that the turbulence collapses and the ETB transition begins when RT > 1 at t = tR (RT: normalized Reynolds power), while the conventional transition criterion (ωE×B>γlin where ωE×B denotes mean flow shear) is satisfied only after t = tC (>tR), when the mean flow shear grows due to positive feedback. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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19. Social capital: a novel platform for understanding social determinants of health in systemic lupus erythematosus.
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Kim, S S, Mancuso, C A, Huang, W-T, and Erkan, D
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CAPITAL shortages , *CAPITAL -- Accounting , *LUPUS erythematosus , *MEDICAID , *CUTANEOUS tuberculosis - Abstract
The article focuses on a study that evaluate how social capital varies in an systemic lupus erythematosus (SLE) sample according to demographic, clinical, and psychosocial variables. Topics discussed include the Adapted Social Capital Assessment Tool (A-SCAT), non-Medicaid insurance and social capital.
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- 2015
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20. Effects of Flunixin Meglumine and Prostaglandin F2α Treatments on the Development and Quality of Bovine Embryos In Vitro.
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Kim, S‐S, Bang, J‐I, Fakruzzaman, M, Lee, K‐L, Ko, D‐H, Ghanem, N, Wang, Z, and Kong, I‐K
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PROSTAGLANDINS , *ARTIFICIAL insemination , *IN vitro studies , *EMBRYO transfer , *POLYMERASE chain reaction - Abstract
Assisted reproduction procedures, such as embryo transfer (ET) and artificial insemination (AI), in cattle could induce the secretion of prostaglandin F2-alpha (PGF2α) from uterine horns which may in turn interrupt embryo development and implantation. This study investigated the effect of flunixin meglumine (FM), prostaglandin F2 alpha (PGF2α) and FM combined with PGF2α supplementation in culture medium (IVC-II) on the development and quality of in vitro produced bovine embryos. The development rate of embryos was significantly higher in the FM group (33.3%) than in control (24.3%), PGF2α (23.9%) and FM + PGF2α groups (24.5%). The percentage of hatched blastocysts was also higher (p < 0.05) in the FM group (41.2%) than in the control (27.8%) and PGF2α groups (19.8%). While, there was no significant difference in total cell number in all experimental groups, the number of apoptotic cells was significantly higher in the PGF2α group (8.2 ± 6.6) than in the control (4.7 ± 3.2), FM (4.7 ± 2.5) and FM + PGF2α (4.9 ± 3.4) groups. Detected by real-time PCR, secreted vesicle seminal protein 1 (SSLP1) and prostaglandin G/H synthase 2 (PTGS2) gene expression decreased (p < 0.05) in the PGF2α group. However, SSLP1 and PTGS2 gene expression in the FM + PGF2α group returned to their baseline levels, similar to the control and FM groups. Caspase 3 (CAPS3) gene expression increased in the PGF2α group compared with other groups (p < 0.05). In conclusion, addition of FM in vitro culture significantly improved embryo development as well as alleviated the negative impact of PGF2α. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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21. Enhanced Electrical Properties of Bi 0.9 Gd 0.1 Fe 0.975 B 0.025 O 3±δ , ( B = Ni, Mn, Cu, Ti, and V) Thin Films.
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Kim, J. W., Kim, S. S., and Bhalla, A. S.
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TRANSITION metals , *DOPING agents (Chemistry) , *CHEMICAL solution deposition , *VACANCIES in crystals , *CURRENT density (Electromagnetism) , *STRAY currents - Abstract
Pure BiFeO3(BFO) and Gd-transition metal co-doped (Bi0.9Gd0.1)(Fe0.975B0.025)O3±δ(B= Ni, Mn, Cu, Ti, and V, denoted by BGdFNi, BGdFMn, BGdFCu, BGdFTi, and BGdFV) films were deposited by using a chemical solution deposition. Enhanced electrical properties were observed for the co-doped films. The BGdFMn film showed the largest 2Prvalue (105.3 μC/cm2at 1470 kV/cm) and the smallest leakage current density (1.49 × 10−5A/cm2at 100 kV/cm). The enhanced electrical properties for the co-doped films are related to the decrease of oxygen vacancies, the stabilization of perovskite structure, and the lattice distortion by the doping elements. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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22. Enhanced protection against Clonorchis sinensis induced by co-infection with Trichinella spiralis in rats.
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Chu, K.‐B., Kim, S.‐S., Lee, S.‐H., Lee, H.‐S., Joo, K.‐H., Lee, J.‐H., Lee, Y.‐S., Zheng, S., and Quan, F.‐S.
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CLONORCHIS sinensis , *HUMORAL immunity , *TRICHINELLA spiralis , *LABORATORY rats , *PARASITE antigens , *ENZYME-linked immunosorbent assay , *ANTIBODY formation - Abstract
Although co-infection with multiple parasites is a frequent occurrence, changes in the humoral immune response against a pre-existing parasite induced as a result of a subsequent parasitic infection remain undetermined. Here, we utilized enzyme-linked immunosorbent assay ( ELISA) to investigate antibody responses, cytokine production and enhanced resistance in Clonorchis sinensis-infected rats (Sprague-Dawley) upon Trichinella spiralis infection. Higher levels of C. sinensis-specific IgG and IgA were elicited upon T. spiralis infection, and these levels remained higher than in rats infected with C. sinensis alone. Upon subsequent infection with T. spiralis, IgG antibodies against C. sinensis appeared to be rapidly boosted at day 3, and IgA antibodies were boosted at day 7. Challenge infection of C. sinensis-infected rats with T. spiralis induced substantial mucosal IgG and IgA responses in the liver and intestine and increases in antibody-secreting plasma cells in the spleen and bone marrow. Subsequent infection also appeared to confer effective control of liver C. sinensis loads, resulting in enhanced resistance. Memory B cells generated in response to C. sinensis infection were rapidly amplified into antibody-secreting cells upon T. spiralis infection. These results indicate that enhanced C. sinensis clearance induced by co-infection is associated with systemic and mucosal IgG and IgA responses. [ABSTRACT FROM AUTHOR]
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- 2014
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23. Effects of longitudinal baffles on particles settling in a sedimentation basin.
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Park, N. S., Kim, S. S., Lee, Y. J., and Wang, C. K.
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BAFFLES (Mechanical device) , *SETTLING basins , *TURBIDITY , *SLUDGE management , *COMPUTATIONAL fluid dynamics , *WATER treatment plants - Abstract
This study was conducted to evaluate the effects of longitudinal baffles on particles settling performance within a full-scale sedimentation basin with a flow rate of 1,000 m3/hr. Comparative experiments on turbidity removal efficiency and sludge deposit distribution were performed in longitudinally baffled and non-baffled sedimentation basins. The turbidity removal rate in the baffled sedimentation basin was observed to be higher than that in the non-baffled basin. In addition, the depth of the sludge deposit in the baffled sedimentation basin was approximately 20% less than that in the non-baffled sedimentation basin, and the sludge concentration was 10% higher. To explain these results and to further investigate the effects of longitudinal baffles, the authors performed computational fluid dynamics (CFD) simulation for both basin types. The results of this CFD simulation indicated that the flow, particularly near the outlet orifice, was more stable in the longitudinally baffled sedimentation basin. Moreover, it could be concluded that the longitudinal baffle enables a fully developed flow and is thus more effective for sedimentation. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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24. Effects of dietary supplementation of citrus by-products fermented with a probiotic microbe on growth performance, innate immunity and disease resistance against Edwardsiella tarda in juvenile olive flounder, Paralichthys olivaceus ( Temminck & Schlegel).
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Lee, B‐J, Kim, S‐S, Song, J‐W, Oh, D‐H, Cha, J‐H, Jeong, J‐B, Heo, M‐S, Kim, K‐W, and Lee, K‐J
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FLATFISHES , *EDWARDSIELLA tarda , *PARALICHTHYS , *DIETARY supplements , *CITRUS - Abstract
Two consecutive studies were conducted to evaluate the dietary supplementation of citrus by-products ( CB) fermented with probiotic bacteria on growth performance, feed utilization, innate immune responses and disease resistance of juvenile olive flounder. In Experiment I, five diets were formulated to contain 0% (control) or 3% four different CB fermented with Bacillus subtilis ( BS), Enterococcus faecium ( EF), Lactobacillus rhamnosus ( LR) and L. plantarum ( LP) (designated as CON, CBF- BS, CBF- EF, CBF- LR and CBF- LP, respectively). During 10 weeks of a feeding trial, growth performance and feed efficiency were not significantly different among all the fish groups. However, fish fed CBF containing diets had significantly higher survivals than the CON group. Disease resistance of fish against Edwardsiella tarda was increased by the fermentation of CB. In Experiment II, we chose the BS as a promising probiotic and formulated five diets to contain 0%, 2%, 4%, 6% and 8% CBF- BS. Growth performance was not significantly affected by the CBF- BS supplementation during 6 weeks of a feeding trial. Innate immunity of fish was significantly enhanced by CBF- BS supplementation. Myeloperoxidase and lysozyme activities were increased in a dose-dependent manner by dietary CBF- BS inclusions. In a consecutive challenge test against E. tarda, an increased disease resistance was found by CBF- BS supplementation. These studies indicate that the fermentation process of CB with probiotic has beneficial effects on innate immunity and thereby increases disease resistance of olive flounder against E. tarda. Bacillus subtilis can be used as a promising probiotic microbe for by-product fermentation in fish feeds. [ABSTRACT FROM AUTHOR]
- Published
- 2013
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25. NMR investigation of the low-temperature dynamics of solid 4He doped with 3He impurities.
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Kim, S. S., Huan, C., Yin, L., Xia, J. S., Candela, D., and Sullivan, N. S.
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RELAXATION (Nuclear physics) , *ANALYTICAL mechanics , *CRYSTAL lattices , *LATTICE dynamics , *SOLID state electronics - Abstract
The lattice dynamics of solid 4He has been explored using pulsed NMR methods to study the motion of 3He impurities in the temperature range (0.05-0.20 K) where experiments have revealed anomalies attributed to superflow or unexpected viscoelastic properties of the solid 4He lattice. We report the results of measurements of the nuclear spin-lattice and spin-spin relaxation times that measure the fluctuation spectrum at high and low frequencies, respectively, of the 3He motion that results from quantum tunneling in the 4He matrix. The measurements were made for 3He concentrations 16 < x3 < 2000 ppm. For 3He concentrations X3 = 16 and 24 ppm, large changes are observed for both the spin-lattice relaxation time T1 and the spin-spin relaxation time T2 at temperatures close to those for which the anomalies are observed in measurements of torsional oscillator responses and the shear modulus. These changes in the NMR relaxation rates were not observed for higher 3He concentrations. [ABSTRACT FROM AUTHOR]
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- 2013
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26. A practical MRI grading system for cervical foraminal stenosis based on oblique sagittal images.
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PARK, H-J., KIM, S. S., LEE, S-Y., PARK, N-H., CHUNG, E-C., RHO, M-H., KWON, H-J., and KOOK, S-H.
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MAGNETIC resonance imaging , *CERVICAL cancer patients , *RADIOLOGISTS , *DIAGNOSTIC imaging ,CERVICAL vertebrae diseases - Abstract
Objective: To propose a new and practical MRI grading method for cervical neural foraminal stenosis and to evaluate its reproducibility. Methods: We evaluated 50 patients (37 males and 13 females, mean age 49 years) who visited our institution and underwent oblique sagittal MRI of the cervical spine. A total of 300 foramina and corresponding nerve roots in 50 patients were qualitatively analysed from C4-5 to C6-7. We assessed the grade of cervical foraminal stenosis at the maximal narrowing point according to the new grading system based on T2 weighted oblique sagittal images. The incidence of each of the neural foraminal stenosis grades according to the cervical level was analysed by χ2 tests. Intra- and interobserver agreements between two radiologists were analysed using kappa statistics. Kappa value interpretations were poor (κ<0.1), slight (0.1⩽κ⩽0.2), fair (0.2<κ⩽0.4), moderate (0.4<κ⩽0.6), substantial (0.6<κ⩽0.8) and almost perfect (0.8<κ⩽1.0). Results: Significant stenoses (Grades 2 and 3) were rarely found at the C4-5 level. The incidence of Grade 3 at the C5-6 level was higher than that at other levels, a difference that was statistically significant. The overall intra-observer agreement according to the cervical level was almost perfect. The agreement at each level was almost perfect, except for only substantial agreement at the right C6-7 by Reader 2. No statistically significant differences were seen according to the cervical level. Overall kappa values of interobserver agreement according to the cervical level were almost perfect. In addition, the agreement of each level was almost perfect. Overall intra- and interobserver agreement for the presence of foraminal stenosis (Grade 0 vs Grades 1, 2 and 3) and for significant stenosis (Grades 0 and 1 vs Grades 2 and 3) showed similar results and were almost perfect. However, only substantial agreement was seen in the right C6-7. Conclusion: A new grading system for cervical foraminal stenosis based on oblique sagittal MRI provides reliable assessment and good reproducibility. This new grading system is a useful and easy method for the objective evaluation of cervical neural foraminal stenosis by radiologists and clinicians. Advances in knowledge: The use of the new grading system for cervical foraminal stenosis based on oblique sagittal MRI can be a useful method for evaluating cervical neural foraminal stenosis. [ABSTRACT FROM AUTHOR]
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- 2013
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27. Clinical correlation of a new practical MRI method for assessing central lumbar spinal stenosis.
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PARK, H-J., KIM, S. S., LEE, Y-J., LEE, S-Y., PARK, N-H., CHOI, Y-J., CHUNG, E-C., and RHO, M-H.
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LUMBAR vertebrae abnormalities , *MAGNETIC resonance imaging , *RADIOLOGISTS , *NEUROLOGICAL research , *DIAGNOSTIC imaging , *PATIENTS - Abstract
Objective: To evaluate interobserver agreement and determine whether a new MRI grading system agrees with symptoms and neurological signs. Methods: We examined 160 patients (72 males and 88 females; mean age 57 years) who underwent MRI of the lumbar spine at our institution and were evaluated by two musculoskeletal radiologists. The presence and grade of central lumbar spinal stenosis (CLSS) at L3-4, L4-5 and L5-S1 were assessed according to a new grading system, the Lee system. The results were correlated with clinical manifestations and neurological examinations [positive neurological manifestation (PNM) and negative neurological manifestation (NNM)]. Statistical analyses were performed using kappa statistics and non-parametric correlation analysis (Spearman's correlation). Results: Interobserver agreement in the grading of CLSS between the two readers was substantial (κ=0.780). Interobserver agreement of the L4-5 level and older age group was high (0.789, 0.814). The correlation coefficient (R) of Reader 1 between MRI Grades 0, 1, 2 or 3 and neurological manifestations (negative or positive) was 0.654; the R of Reader 2 was 0.591. In the younger age group (<57 years), the R of Reader 1 was 0.634 and the R of Reader 2 was 0.500. In the older age group (⩾57 years), the R of Reader 1 was 0.650 and theR of Reader 2 was 0.645. Correlation coefficients were higher at the L3-4 level (0.612-0.678) than at other levels but did not show statistical significance (p>0.05). Conclusion: Interobserver agreement for the new CLSS grading system was substantial. Grade 0 was associated with NNMs and Grade 3 with PNMs in this cohort. Grade 2 demonstrates more cases of PNM than NNM but requires further evaluation. Correlations between MRI grades and clinical manifestations were moderate and slightly higher in older patients. Advances in knowledge: The new practical MRI grading method can be useful in the categorisation of CLSS and shows strong clinical correlation. [ABSTRACT FROM AUTHOR]
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- 2013
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28. Role of Reynolds stress and toroidal momentum transport in the dynamics of internal transport barriers.
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Kim, S. S., Jhang, Hogun, and Diamond, P. H.
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REYNOLDS stress , *TOROIDAL plasma , *MOMENTUM (Mechanics) , *COMPUTER simulation , *NUCLEAR excitation , *DISTRIBUTION (Probability theory) , *FLUID dynamics - Abstract
We study the interplay between intrinsic rotation and internal transport barrier (ITB) dynamics through the dynamic change of the parallel Reynolds stress. Global flux-driven gyrofluid simulations are used for this study. In particular, we investigate the role of parallel velocity gradient instability (PVGI) in the ITB formation and the back transition. It is found that the excitation of PVGI is followed by a change in the Reynolds stress which drives a momentum redistribution. This significantly influences E×B shear evolution and subsequent ITB dynamics. Nonlocal interactions among fluctuations are also observed during the PVGI excitation, resulting in turbulence suppression at the ITB. [ABSTRACT FROM AUTHOR]
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- 2012
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29. Implementation of gravitational shocks in two-dimensional Fokker-Planck models.
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Kim, S. S., Shin, J., and Takahashi, K.
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GRAVITATION , *FOKKER-Planck equation , *PARTIAL differential equations , *ASTRONOMICAL perturbation , *DISPERSION (Chemistry) - Abstract
We derive analytical formulae for drift and dispersion terms of energy and angular momentum ((ΔE), ((ΔE)2), (ΔJ), and ((ΔJ)2)) as well as their cross term ((ΔEΔJ)) for stellar systems under an impulsive perturbation. These terms are expressed as functions of E, J, and orbit averages of powers of radius (r) and the product of radius and velocity (rv), and we confirm our formulae with a numerical simulation. Then with another numerical simulation for a time-varying (Gaussian) perturbation, we find that the adiabatic corrections suggeted by Gnedin and Ostriker can be applied not only to the energy changes (drift and dispersion) but also to the angular momentum changes, if the changes are expressed as functions of energy only. The corrections do not describe the changes accurately when the changes are considered as functions of both energy and angular momentum. The deviations between the numerical simulation and analytical expectations are consierable only in the cluster core though, where the effect of perturbation is relatively weaker. These results are to be implemented in two-dimensional (E - J) Fokker-Planck models of the evolution of globular clusters. [ABSTRACT FROM AUTHOR]
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- 2012
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30. Improved Electrical Properties of Cr-Doped K 0.5 Bi 4.5 Ti 4 O 15 Thin Films Fabricated by Chemical Solution Deposition.
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Do, D., Kim, S. S., and Bhalla, A. S.
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THIN films , *SOLID state electronics , *ELECTROMAGNETIC fields , *ELECTRIC fields , *SURFACES (Technology) - Abstract
Ferroelectric K0.5Bi4.5Ti4O15 (KBTi) and Cr-doped K0.5Bi4.5Ti4O15 ((K0.5Bi4.5Ti3.97 Cr0.03O15-δ), (KBTC)) thin films were prepared on Pt(111)/Ti/SiO2/Si substrates by using a chemical solution deposition method. The thin films were annealed at 750°C for 3 min by a rapid thermal annealing process under oxygen atmosphere. Compared to pure KBTi thin film, there was no structural change while improved ferroelectric and leakage current properties were observed. The values of remnant polarization (2Pr ) and coercive field (2Ec ) were 50.9 μC/cm2 and 244 kV/cm at an applied electric field of 300 kV/cm, respectively. The 2Pr we observed is compatible with that of doped bismuth layer-structured ferroelectric thin films. Leakage current density was 6.00 × 10−7 A/cm2 at 200 kV/cm. The enhanced properties of KBTC could be explained by a defect dipole (Cr′Ti-V) and increased average grain size. [ABSTRACT FROM AUTHOR]
- Published
- 2011
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31. Anisotropic TGO rumpling in EB-PVD thermal barrier coatings under in-phase thermomechanical loading
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Balint, D.S., Kim, S.-S., Liu, Yu-Fu, Kitazawa, R., Kagawa, Y., and Evans, A.G.
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ANISOTROPY , *THERMAL barrier coatings , *METALS , *THERMOMECHANICAL treatment , *AXIAL loads , *ELECTRON beams , *PHYSICAL vapor deposition , *THICKNESS measurement , *METALLIC oxides , *DEFORMATIONS (Mechanics) , *MULTILAYERED thin films - Abstract
Abstract: An electron beam physical vapor deposited (EB-PVD) Y2O3–ZrO2 thermal barrier system has been tested under in-phase thermomechanical fatigue (TMF) conditions with thermal gradient in the through-thickness direction. Undulations in the thermally grown oxide (TGO) were observed to have clear anisotropic behavior with respect to the directions parallel and perpendicular to the loading axis. It was found that undulation wavelengths were nearly the same in both directions but the amplitude in the perpendicular direction was much larger than in the parallel direction. A recent model of TGO rumpling was adapted and used to analyze and explain the origins of the observed rumpling behavior under TMF conditions. Methods for deducing variation in the coefficient of thermal expansion with temperature and in the creep properties of the substrate from the experimental strain data are also presented in the course of the derivations. Model results show that tensile stress applied in the loading direction can overcome the compression occurring from lateral expansion during oxide formation, causing undulations to flatten; undulations perpendicular to the loading axis are unaffected. However, ratcheting in the strain cycle experienced by the substrate, which occurs naturally by substrate creep, is necessary for anisotropic rumpling under cyclic stress conditions. Model predictions for constant applied stress are also presented, demonstrating a reversal in the direction of undulation alignment under compression. A threshold stress is identified, in both tension and compression, sufficient to produce appreciable anisotropic rumpling. The model predictions provide a clear mechanism for the anisotropy and further evidence that the lateral expansion strain in the oxide is the driving force for oxide rumpling. [Copyright &y& Elsevier]
- Published
- 2011
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32. Comparison of saline wastewater treatment performance of SBR with repeated starvation under aerobic and non-aerobic conditions.
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Moon, B. H., Kim, S. S., Yoon, C. H., and Park, K. H.
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WASTEWATER treatment , *SALINE waters , *STARVATION , *SEQUENCING batch reactor process , *FRACTALS - Abstract
This study investigated the effects of repeated starvation and feeding on the performance of a sequencing batch reactor (SBR) used for treating saline wastewater. The effects of aerobic and non-aerobic conditions on the sludge during starvation were evaluated to recover the performance of the SBR in terms of floc size and pollutant removal after resuming wastewater feeding. The floc size, fractal dimension, sludge volume index (SVI), specific oxygen uptake rate (SOUR), and pollutant removal efficiency were monitored. Experiment results revealed that the floc size and fractal dimensions decreased during starvation under both aerobic and non-aerobic conditions and increased after re-feeding wastewater. However, the difference in floc physical characteristics and performance depended on the starvation condition and was pronounced as starvation and re-feeding were repeated. The floc size and fractal dimensions decreased from 152.7 to 72.2 and 1.98 to 1.79 at the end of the fourth starvation period, resulting in deterioration of the sludge settleability and effluent quality. On the other hand, the floc size and fractal dimensions decreased from 158.7 to 135.7 and 1.95 to 1.81 at the end of the fourth starvation period but remained relatively constant after sludge adaptation. Some correlations were observed between the parameters monitored in this study. The results showed that maintaining the sludge under non-aerobic conditions was an effective strategy for reducing the effects of repeated starvation. [ABSTRACT FROM AUTHOR]
- Published
- 2011
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33. Hyperuricemia in Kidney Transplant Recipients with Intact Graft Function
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Kim, K.M., Kim, S.-S., Han, D.J., Yang, W.S., Park, J.S., and Park, S.-K.
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KIDNEY transplantation , *HYPERURICEMIA , *DISEASE prevalence , *GLOMERULAR filtration rate , *URIC acid , *DIABETES - Abstract
Abstract: Objectives: The aim of this study was to investigate the prevalence of hyperuricemia and factors predicting its occurrence, and to establish the relationship over time between serial changes in estimated glomerular filtration rate (eGFR) and uric acid (UR) concentration in kidney transplant (KT) recipients with eGFR >60 mL/min/1.73 m2. Methods: Adult patients who underwent KT at the Asan Medical Center between 1990 and 2008 and maintained eGFR >60 mL/min/1.73 m2 were retrospectively assessed. Clinical and laboratory data were obtained from inpatient and outpatient charts and from the hospital electronic database. Results: Of 356 patients, 301 (84.55%) had normal UR levels and 55 (15.45%) had hyperuricemia. After multivariate adjustment, transplant duration, male gender, eGFR, diabetes mellitus (DM), and calcium level were associated with higher mean UR levels. Mean UR level increased significantly and mean eGFR decreased significantly during the first year after transplantation, but there were no significant differences over the next 4 years. Serial UR and eGFR levels changed almost simultaneously. Conclusions: Transplantation duration, male gender, eGFR level, DM, and serum calcium level were risk factors for hyperuricemia in kidney recipients with intact graft function. Increased uric acid after KT did not significantly affect graft function. [ABSTRACT FROM AUTHOR]
- Published
- 2010
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34. The dissolution of ThO(cr) in carbonate solutions and a granitic groundwater.
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Kim, S. S., Baik, M. H., Choi, J. W., Shin, H. S., and Yun, J. I.
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CARBONATES , *IONS , *THORIUM , *ACTINIDE elements , *NUCLEAR chemistry - Abstract
ThO(cr) was dissolved in the solutions containing various carbonate ion concentrations, and the results were compared with thorium solubility in a domestic granitic groundwater having very low ionic strength. The soluble thorium concentration excluding colloids after phase separation increased with increasing carbonate concentration. However, the thorium concentration in the real groundwater was remarkably greater than that in the carbonate-containing solutions with a similar concentration of carbonate and pH condition. This might be attributable to other species as well as Th(OH)(aq) and Th(OH)(CO). These species form colloids or precipitates, and their concentration can be reduced in the ultra-filtered solution by an aging effect. [ABSTRACT FROM AUTHOR]
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- 2010
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35. Orientation Dependence of Electrical Properties of Bi3.15Pr0.85Ti3O12 Thin Films.
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Do, D., Kim, S. S., Kim, J. W., Kim, W. -J., Song, T. K., Sung, Y. S., Kim, M. H., and Choi, B. C.
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ELECTRIC properties of thin films , *BISMUTH compounds , *SOLUTION (Chemistry) , *FERROELECTRICITY , *CRYSTALLOGRAPHY , *POLARIZATION (Electricity) - Abstract
Randomly oriented and c-axis-oriented Bi3.15Pr0.85Ti3O12 (BPT) thin films were prepared by a chemical solution deposition method. Ferroelectric and leakage current properties were strongly related to the crystallographic orientation of BPT thin film. The values of remnant polarization (2Pr) and leakage current density were 74 μC/cm2 at 250 kV/cm and 3.4 × 10-8 A/cm2 at 125 kV/cm for the randomly oriented thin film, respectively, and 16 μC/cm2 and 6.9 × 10-6 A/cm2 for the c-axis-oriented thin film, respectively. The result indicates that the polarization vector of BPT thin films is not oriented along the c-axis. [ABSTRACT FROM AUTHOR]
- Published
- 2010
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36. Axial length and intraoperative posterior vitreous detachment as predictive factors for surgical outcomes of diabetic vitrectomy.
- Author
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Song, W. K., Kim, S. S., Yi, J.-H., Byeon, S. H., Koh, H. J., Lee, S. C., and Kwon, O. W.
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VITRECTOMY , *POSTERIOR segment (Eye) , *VITREOUS humor , *RETINAL detachment , *SURGICAL complications , *PEOPLE with diabetes , *MEDICAL care - Abstract
AimsTo evaluate the relationship of axial length (AXL), intraoperatively assessed posterior vitreous detachment (PVD) status, and surgical outcomes of diabetic vitrectomy.MethodsRetrospective, consecutive case series. Clinical records were reviewed for 115 eyes (50 males, 65 females) with more than a 6-month follow-up who underwent diabetic vitrectomy from a single surgeon. Thirty-three eyes had vitreous haemorrhage, 37 had tractional retinal detachment (TRD) threatening the macula, 43 had TRD involving the macula, and two had neovascular glaucoma. AXL was measured preoperatively by ultrasonography, and PVD status was classified intraoperatively: broad vitreo-retinal adhesion as no PVD, PVD at the macular area with attachment at the disc as incomplete PVD, and complete PVD.ResultsForty-four eyes had no PVD, 23 had incomplete PVD, and 48 had complete PVD. A majority of the no PVD group had macula off TRD (97.7%), whereas vitreous haemorrhage (68.7%) predominated in the complete PVD group. Longer AXLs were noted in the complete PVD group compared with the no PVD and incomplete PVD groups (ANOVA in three groups P=0.0001). Univariate analysis showed that AXL had an influence on anatomical success (P=0.02). Multiple logistic regression analysis yielded that PVD status is a significant predictor of the final best corrected visual acuity (BCVA)>20/100, and BCVA>20/40 (P=0.01, P=0.02).ConclusionsIntraoperatively assessed PVD status is a prognostic factor for functional outcomes of diabetic vitrectomy. Shorter AXL was associated with lesser PVD. In eyes with a lack of PVD, careful timing and decision of surgery are mandatory. [ABSTRACT FROM AUTHOR]
- Published
- 2010
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37. Sorption of 14C, 99Tc, 137Cs, 90Sr, 63Ni, and 241Am onto a rock and a fracture-filling material from the Wolsong low- and intermediate-level radioactive waste repository, Gyeongju, Korea.
- Author
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Baik, M. H., Kim, S. S., Lee, J. K., Lee, S. Y., Kim, G. Y., and Yun, S. T.
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ABSORPTION , *RADIOACTIVE waste repositories , *RADIOISOTOPES , *PARTITION coefficient (Chemistry) , *GROUNDWATER - Abstract
Sorption experiments for radionuclides such as 14C, 99Tc, 137Cs, 90Sr, 63Ni, and 241Am were conducted using two different groundwaters (GM-1 and SS-5) and solid materials (granodiorite and fracture-filling material) sampled from the Wolsong low- and intermediate-level radioactive waste (LILW) repository, Gyeongju, Korea. The distribution coefficients of the radionuclides, Kd’s, were obtained and their sorption properties were discussed for each radionuclide. For all sorbing radionuclides, the Kd values for the fracture-filling material were observed to be higher than those for granodiorite regardless of the groundwater. The Kd values were increased in the sequence 99Tc < 14C < 90Sr < 137Cs < 63Ni < 241Am regardless of sorbent types implying that the sorption of radionuclides onto geological media is affected by their chemical behavior in accordance with geochemical environments. Anionic radionuclides such as 14C and 99Tc showed very low Kd values both for the granodiorite and fracture-filling material. The mineralogical composition of the geological media and groundwater conditions was also observed to be important in the sorption of sorbing radionuclides, especially in the case of strongly sorbing radionuclides. [ABSTRACT FROM AUTHOR]
- Published
- 2010
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38. External cavity widely tunable quantum cascade laser based hollow waveguide gas sensors for multianalyte detection
- Author
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Young, C., Kim, S.-S., Luzinova, Y., Weida, M., Arnone, D., Takeuchi, E., Day, T., and Mizaikoff, B.
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GAS detectors , *TUNABLE lasers , *CHLOROHYDROCARBONS , *QUANTUM theory , *WAVEGUIDES , *QUANTITATIVE research , *ETHYL chloride , *FOURIER transform infrared spectroscopy - Abstract
Abstract: In the study presented here, quantitative detection of ethyl chloride, dichloromethane, and trichloromethane individually and in mixture has been demonstrated using an external cavity broadly tunable quantum cascade laser (EC-QCL) based hollow waveguide gas sensor. The EC-QCL has been characterized by coupling into a FT-IR spectrometer documenting sufficient optical power output across a frequency tuning range from 1297cm−1 to 1219cm−1. Concentrations as low as 4 ppb for ethyl chloride, 7ppm for dichloromethane, and 11 ppb for trichloromethane were detected during exponential dilution experiments with the EC-QCL precisely tuned to selective absorption frequencies of the Q-branch for each constituent at 1287.25cm−1, 1262cm−1, and 1220cm−1, respectively. [Copyright &y& Elsevier]
- Published
- 2009
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39. Solubility of neptunium oxide in the KURT (KAERI Underground Research Tunnel) groundwater.
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Kim, S. S., Baik, M. H., and Kang, K. C.
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NEPTUNIUM , *OXIDES , *GROUNDWATER , *RADIOISOTOPES , *ACTINIDE elements , *IONS - Abstract
The solubilities of NpO2(s) in the KURT (KAERI Underground Research Tunnel) granitic groundwater with low ionic strength were measured experimentally and calculated by a geochemical code. Then these results were compared with each other as well as with foreign results. The concentrations of neptunium were measured as 6·10−8−2·10−8 mol/L at a pH = 9.5–11.1 and Eh = −0.2 V, and less than 5·10−9 mol/L at a pH = 11.8–13.0 and Eh = −0.3–0.44 V. The dominant aqueous species were presumed as Np(OH)x(CO3)y 4−x−2y complexes and Np(OH)4(aq) at pH = 9.5–13 under the Eh<−0.2 V reducing condition. [ABSTRACT FROM AUTHOR]
- Published
- 2009
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40. ORIENTATION DEPENDENCE OF FERROELECTRIC AND DIELECTRIC PROPERTIES IN CaBi4Ti4O15 THIN FILMS.
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DO, D., KIM, S. S., KIM, J. W., LEE, Y. I., and BHALLA, A. S.
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SOLID state electronics , *FERROELECTRICITY , *DIELECTRICS , *THIN films , *ELECTRIC fields - Abstract
Ferroelectric CaBi4Ti4O15 (CBTi) thin films with random orientation and high c-axis orientation were prepared on a Pt(111)/Ti/SiO2/Si(100) substrate by a chemical solution deposition method. We observed a strong dependence of ferroelectric and dielectric properties on the film orientation. The CBTi thin film with random orientation exhibited remnant polarization (2Pr) of 54 μ C/cm2 at an applied electric field of 250 kV/cm and dielectric constant (ε) of 412 at a frequency of 1 kHz. The values of 2Pr and ε were larger than those observed in the CBTi thin film with high c-axis orientation. In addition, the randomly oriented thin film showed lower leakage current density than the highly c-axis-oriented thin film. [ABSTRACT FROM AUTHOR]
- Published
- 2009
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41. EFFECT OF VARIOUS HEAT TREATMENT PROCESSES ON FATIGUE BEHAVIOR OF TOOL STEEL FOR COLD FORGING DIE.
- Author
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JIN, S. U., KIM, S. S., LEE, Y. S., KWON, Y. N., and LEE, J. H.
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HEAT treatment of steel , *STEEL metallurgy , *FRACTOGRAPHY , *MICROSTRUCTURE , *STRAINS & stresses (Mechanics) , *STRENGTH of materials - Abstract
Effects of various heat treatment processes, including "Q/T (quenching and tempering)", "Q/CT/T (Quenching, cryogenic treatment and tempering)", "Q/T (quenching and tempering) + Ti-nitriding" and "Q/CT/T (Cryogenic treatment and tempering) + Ti-nitriding", on S-N fatigue behavior of AISI D2 tool steel were investigated. The optical micrographs and Vicker's hardness values at near surface and core area were examined for each specimen. Uniaxial fatigue tests were performed by using an electro-magnetic resonance fatigue testing machine at a frequency of 80 Hz and an R ratio of -1. The overall resistance to fatigue tends to decrease significantly with Ti-nitriding treatment compared to those for the general Q/T and Q/CT/T specimens. The reduced resistance to fatigue with Ti-nitriding is discussed based on the microstructural and fractographic analyses. [ABSTRACT FROM AUTHOR]
- Published
- 2008
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42. Diagnostic efficacy in knee MRI comparing conventional technique and multiplanar reconstruction with one-millimeter FSE PDW images.
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Yoon, Y. C., Kim, S. S., Chung, H. W., Choe, B-K., and Ahn, J. H.
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KNEE diseases , *MAGNETIC resonance imaging , *CRUCIATE ligaments , *IMAGING systems , *DIAGNOSTIC imaging - Abstract
Background: Magnetic resonance (MR) imaging has proved to be an excellent tool in diagnosing injuries of the cruciate ligaments and menisci. However, multiple planes and sometimes optimal oblique or double-oblique scan planes are needed due to the variability in the positioning of important structures, which means there is a lower throughput and longer scanning time.Purpose: To compare the performance of a 1-mm-thickness fast spin-echo (FSE) proton-density-weighted (PDW) MR imaging technique with multiplanar reconstruction (MPR) in diagnosing tears of the menisci and cruciate ligaments with that of conventional MR imaging.Material and Methods: Twenty-five consecutive patients underwent preoperative conventional and 1-mm-thickness FSE PDW MR imaging with subsequent knee arthroscopic surgery. Two musculoskeletal radiologists evaluated the status of the cruciate ligaments and menisci using two sets of MR images (method A: conventional images including seven sequences, taking 26 min; method B: 1-mm-thickness FSE PDW images with MPR, taking 7 min 20 s). The diagnostic efficacies of both methods for tears of the cruciate ligament and menisci were calculated and compared.Results: Arthroscopic surgery revealed 10 anterior cruciate ligament (ACL) tears, one posterior cruciate ligament (PCL) tear, and 26 meniscal tears. The diagnostic values of both methods were 100% for a cruciate ligament tear. The diagnostic values (sensitivity, specificity, accuracy, positive predictive value, and negative predictive value) for meniscal tears were 90%, 100%, 96%, 100%, and 94% for method A, and 95%, 100%, 98%, 100%, and 97% for method B, respectively. There were no significant differences in the diagnostic values between methods A and B.Conclusion: 1-mm-slice-thickness FSE PDW imaging with MPR showed comparable performance in diagnosing tears of the cruciate ligaments and menisci to conventional sequences but the scan time was much shorter. Therefore, this technique (method B) might improve the throughput of a 3T MR imaging system. [ABSTRACT FROM AUTHOR]- Published
- 2007
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43. Development of cube textured Ni–5at.%W alloy substrates for YBCO coated conductor application using a powder metallurgy process
- Author
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Kim, S.-S., Tak, J.-S., Bae, S.-Y., Chung, J.-K., Ahn, I.-S., Kim, C.-J., Kim, K.-W., and Cho, K.-K.
- Subjects
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INDUSTRIAL use of oxygen , *POWDER metallurgy , *COMPACTING , *METALLURGY - Abstract
Abstract: In this paper, Ni–5at.%W alloy substrate for YBCO coated conductor was fabricated by a dry powder metallurgy process including powder compaction, cold isostatic pressing (CIP), cold rolling and annealing for recrystallization. Ni and W powders were ball-milled at this process for various times of 10, 30, 50 and 100h in argon atmosphere. The rod-like Ni–W alloy compacts were sintered at 1150°C for 1h in 96%Ar–4%H2 atmosphere. The sintered rods were cold rolling into thin tape of 70–90μm thickness with 5% reduction at each path. The Ni–W alloy tapes were annealed at 800–1200°C in an atmosphere of 96%Ar–4%H2 mixing gas for the development of cube texture. The tape with the best properties of low surface roughness, small grain size and strong cube texture was obtained at the condition annealed at 1200°C using ball-milled powder for 30min. The W addition to Ni improved the mechanical properties by solid solution hardening and inhibited grain growth for annealing heat treatment. The tapes were characterized by X-ray pole-figure, optical microscopy (OM), scanning electron microscopy (SEM) and scanning probe microscopy (SPM). [Copyright &y& Elsevier]
- Published
- 2007
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44. Electrostatic potential fluctuation induced by charge discreteness in a nanoscale trench.
- Author
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Taesang Lee, Kim, S. S., Jho, Y. S., Park, Gunyoung, and Chang, C. S.
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FLUCTUATIONS (Physics) , *ELECTRIC fields , *COULOMB excitation , *NANOSTRUCTURED materials , *IONS , *PLASMA dynamics - Abstract
A simplified two-dimensional Monte Carlo simulation is performed to estimate the charging potential fluctuations caused by strong binary Coulomb interactions between discrete charged particles in nanometer scale trenches. It is found that the discrete charge effect can be an important part of the nanoscale trench research, inducing scattering of ion trajectories in a nanoscale trench by a fluctuating electric field. The effect can enhance the ion deposition on the side walls and disperse the material contact energy of the incident ions, among others. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
45. Modified Korteweg–de Vries theory of non-monotonic double layers in multi-species plasma.
- Author
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KIM, T. H., KIM, S. S., KIM, H. Y., and HWANG, J. H.
- Subjects
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MONOTONIC functions , *PLASMA gases , *KORTEWEG-de Vries equation , *ELECTRIC fields , *IONS , *IONOSPHERE , *ELECTRONS , *EIGENVALUES , *ACOUSTIC surface waves - Abstract
The analytic solution for the time stationary non-monotonic double layers in multi-species plasma is presented. This solution is the analytic extension of the monotonic double layer and the solitary hole. We have derived the modified Korteweg–de Vries equation in plasmas, taking account of negative ion effects. The effects of negative ion and density on the properties of the non-monotonic double layer are discussed. [ABSTRACT FROM PUBLISHER]
- Published
- 2007
- Full Text
- View/download PDF
46. Effect of microstructural variables on tensile behaviour of A356 cast aluminium alloy.
- Author
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Hong, S. J., Kim, S. S., Lee, J. H., Kwon, Y. -N., and Lee, Y. S.
- Subjects
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MICROSTRUCTURE , *ALUMINUM alloys , *MORPHOLOGY , *EUTECTICS , *REGRESSION analysis , *FRACTOGRAPHY , *ALLOYS - Abstract
The effects of microstructural variables, including secondary dendrite arm spacing (SDAS), the size of primary α phase, the aspect ratio of eutectic Si particle and the thickness of eutectic wall structure, on tensile behaviour of A356 cast aluminium alloy, were quantitatively identified using linear regression analysis method. For systematic microstructural control of A356 specimen, directional solidification method was used with different solidification rates of 5, 25, 50 and 100 μm s-1 respectively. The linear regression analysis suggests that each microstructural variable affects tensile strength and tensile elongation of A356 cast aluminium alloy in a similar fashion. The change in tensile behaviour with varying microstructural variables in A356 cast aluminium alloy is discussed based on fractographic and micrographic observations. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
47. Corrosion behaviour of friction stir welded AZ31B Mg in 3·5%NaCl solution.
- Author
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Jang, Y. H., Kim, S. S., Yim, C. D., Lee, C. G., and Kim, S. J.
- Subjects
- *
FRICTION welding , *PRESSURE welding , *MANGANESE alloys , *CORROSION & anti-corrosives , *HEAT treatment , *HEAT of wetting - Abstract
The corrosion behaviour of friction stir welded AZ31B-H24 and -T4 Mg alloys in 3·5%NaCl solution was examined based on potentiodynamic test and constant immersion test results. For friction stir welded AZ31B-H24 specimens, the corrosion potential was higher compared with as received (i.e. parent) specimens, while the trend was reversed for AZ31B-T4 specimens. The present corrosion test results appear to be closely related to the grain size of the friction stir welded specimens. The effects of prior T4 heat treatment, and subsequent microstructural evolution, with friction stir welding on the corrosion behaviour is discussed based on potentiodynamic tests, constant immersion tests and micrographic observation. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
48. Effects of Annealing Temperature on the Electrical Properties of Cr-Substituted BiFeO3 Thin Films.
- Author
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Kim, J. K., Kim, S. S., Park, M. H., Kim, J. W., Choi, E. J., Ha, T. G., Cho, H. K., Guo, R., and Bhalla, A. S.
- Subjects
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ELECTRIC properties of thin films , *ANNEALING of metals , *RECRYSTALLIZATION (Metallurgy) , *FERROELECTRICITY , *HYSTERESIS - Abstract
Cr-substituted BiFeO3 (BFCr-3 mol%) thin films were deposited on Pt(200)/TiO2/SiO2/Si substrates by a chemical solution deposition. The coated films were annealed in the temperature range of 500°C∼ 600°C for 30 min under nitrogen atmosphere. The electrical properties of BFCr thin films were found to be sensitive to the annealing temperature. It was found that BFCr thin films exhibited good ferroelectric properties, such as an improved leakage-current density and P-E hysteresis characteristics. The BFCr thin film annealed at 525°C exhibits a low leakage current density of 9.2 × 10- 7 A/cm2 at an applied electric field of 100 kV/cm. The films exhibited a well-saturated hysteresis loop with a remanent polarization (Pr) of 47 μC/cm2 at room temperature. The reason for the improved leakage current and ferroelectric properties in BFCr thin films can be attributed to the effects of increased grain size and oxygen vacancies reduced by Cr doping. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
49. The effects of container materials and buffer additives on decreasing the iodide concentration in a disposal vault for spent nuclear fuel.
- Author
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Kim, S. S., Chun, K. S., Choi, J. W., Kim, S. K., and Cho, W. J.
- Subjects
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IODIDES , *NUCLEAR fuels , *RADIOACTIVE wastes & the environment , *ION migration & velocity , *SPENT reactor fuels , *CORROSION & anti-corrosives , *ADSORPTION (Chemistry) , *BENTONITE - Abstract
To retard the migration of iodine released from a spent fuel after the break of a container, the reducing effects on the concentration of the iodide by container corrosion products and some buffer additives were examined in a solution with bentonite. Iron and copper, and their corrosion products scarcely reduced the iodide concentration. And kaolinite, chalcopyrite, pyrite, copper ore and galena, known as having a sorption property for iodine, did not noticeably sorb the iodide. However, palm active carbon, silver metal and Ag2O lowered the iodide concentration. Especially, Ag2O put into a disposal container would effectively hinder the migration of iodine to the outside of a disposal vault without a great loss if the pore size of the compacted buffer layer is maintained below 1 μ m. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
50. Microstructure and Electrical Properties of Cosubstituted BiFeO3 Thin Films Prepared by a Chemical Solution Deposition.
- Author
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Kim, J. K., Kim, S. S., Park, M. H., Choi, E. J., Kim, J. W., Guo, R., and Bhalla, A. S.
- Subjects
- *
MICROSTRUCTURE , *FERROELECTRICITY , *BISMUTH compounds , *FERRITES , *THIN films , *HYSTERESIS loop , *ELECTRIC leakage , *ELECTRIC fields - Abstract
5 mol % La3 +, Nd3 + or Y3 +-cosubstituted BiFe0.97Cr0.03O3 thin films (denoted by BLaFCr, BNdFCr, and BYFCr, respectively) have been successfully deposited on Pt (200)/TiO2/SiO2/Si substrates by a chemical solution deposition method. Well-saturated ferroelectric hysteresis loops and low leakage current densities have been observed in BLaFCr, BNdFCr, and BYFCr thin films with single-phase structure. The values of remanent polarization (Pr) and coercive field (Ec) were 64 μ C/cm2 and 275 kV/cm, 61 μC/cm2 and 290 kV/cm, and 31 μ C/cm2 and 315 kV/cm for BLaFCr, BNdFCr and BYFCr thin films at the maximum electric field of 712 kV/cm, respectively. In the present study, the differences in values of Pr seem to be related to the doped ionic radii. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
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