425 results on '"Keon, Kim"'
Search Results
152. International Symposium on Advanced Material Research
- Author
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Dong Keon Kim and Dong Keon Kim
- Subjects
- Materials science--Congresses, Materials--Congresses
- Abstract
ISAMR 2017Selected, peer reviewed papers from the International Symposium on Advanced Material Research (ISAMR 2017), March 17-19, 2017, Seoul, South-Korea
- Published
- 2017
153. Statistical beamforming for wireless backhaul of small moving cells in massive MIMO systems
- Author
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Geon-Woong Jung, Hyoung-Keon Kim, and Yong-Hwan Lee
- Subjects
Beamforming ,Computer science ,Wireless backhaul ,020206 networking & telecommunications ,020302 automobile design & engineering ,02 engineering and technology ,Base station ,0203 mechanical engineering ,Sampling process ,Computer Science::Networking and Internet Architecture ,0202 electrical engineering, electronic engineering, information engineering ,Electronic engineering ,Channel correlation matrix ,Eigenvalues and eigenvectors ,Computer Science::Information Theory ,Mimo systems ,Communication channel - Abstract
A small moving cell (SMC) system is proposed to be a potential system in the next-generation cellular system. However, it is challenging issue to provide wireless backhaul links to the SMCs which may have high mobility. In this paper, we propose statistical beamforming (SBF) technique to provide the wireless backhaul links in massive MIMO systems. Unlike most of the conventional SBF schemes, we consider multiple antennas at the receiver side where the base station (BS) needs to determine the proper number of SBF beams. We first determines candidates of SBF beams as eigenvectors corresponding to dominant eigenvalues of channel correlation matrix (CCM). The average achievable SINR can be estimated using a Monte-Carlo sampling process without ST-CSI at the BS, then the proper beams and the transmit powers are adjusted by iterative water-filling algorithm. The simulation results show that the proposed SBF scheme is quite feasible for the wireless backhaul of SMCs in high mobility without the feedback of short-term channel information.
- Published
- 2017
154. A Two-Surface Viscoplastic Model for the Structural Steel
- Author
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Jinkyu Kim and Dong-Keon Kim
- Subjects
Surface (mathematics) ,Materials science ,Aerospace Engineering ,Ocean Engineering ,Monotonic function ,02 engineering and technology ,Numerical simulation ,Plasticity ,Two-surface model ,Stress (mechanics) ,0203 mechanical engineering ,General Materials Science ,Kinematic hardening ,lcsh:QC120-168.85 ,Civil and Structural Engineering ,Viscoplasticity ,Computer simulation ,business.industry ,Mechanical Engineering ,Rate dependent ,Structural engineering ,021001 nanoscience & nanotechnology ,020303 mechanical engineering & transports ,Mechanics of Materials ,Automotive Engineering ,lcsh:Descriptive and experimental mechanics ,lcsh:Mechanics of engineering. Applied mechanics ,lcsh:TA349-359 ,0210 nano-technology ,business - Abstract
As extension of the previous two-surface model in plasticity, a two-surface model for viscoplasticity is presented herein. In order to validate and investigate the performance of the proposed model, several numerical simulations are undertaken especially for structural steel under monotonic and cyclic loading cases, where experimental results and numerical results from the rate dependent kinematic hardening model are also provided for the reference. For all the cases studied, the proposed model can appropriately account for the rate-effects in both maximum stress and hysteretic shapes.
- Published
- 2017
155. Effect of Coronal Scoliotic Curvature on Sagittal Spinal Shape: Analysis of Parameters in Mature Adolescent Scoliosis Patients
- Author
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Jae Hyuk Yang, Keon Kim, Si Young Park, Jae-Young Hong, and Seung-Woo Suh
- Subjects
Male ,Adolescent ,Radiography ,Scoliosis ,Curvature ,03 medical and health sciences ,Young Adult ,0302 clinical medicine ,Medicine ,Humans ,Orthopedics and Sports Medicine ,030222 orthopedics ,business.industry ,Background data ,Anatomy ,medicine.disease ,Sagittal plane ,Spine ,Adolescent scoliosis ,medicine.anatomical_structure ,Coronal plane ,Surgery ,Female ,Neurology (clinical) ,business ,030217 neurology & neurosurgery ,Shape analysis (digital geometry) - Abstract
A radiographic analysis with scoliosis patients.To analyze correlations between sagittal spinal alignment and coronal scoliotic curvature.Sagittal spinal alignment and scoliosis may have a significant relationship, and schematic analysis is needed.The study group was comprised of 163 patients with adolescent idiopathic scoliosis. Subjects underwent anteroposterior and lateral radiographs of the whole spine including hip joints. The radiographic parameters used were magnitude, location and direction of curve, thoracic kyphosis, thoracolumbar kyphosis, lumbar lordosis, sagittal balance, sacral slope, and pelvic angle. Subjects were classified into 4 groups according to the severity of coronal curvature: Cobb angle ≤20 degrees, Cobb angle 21-40 degrees, Cobb angle 41-60 degrees, and Cobb angle60 degrees. In addition, subjects were divided into 4 subgroups according to Roussouly's classification (types 1-4) of sagittal spinal shape. Schematic analysis was performed to determine the relationship between coronal and sagittal parameters.Analysis of parameters with severity of coronal curvature, thoracic kyphosis, and sacral slope were significantly higher in high-grade scoliosis (P0.05). However, the pelvic angle was higher in low-grade scoliosis, and sagittal balance showed a significantly higher positive value in low-grade scoliosis (P0.05). In the analysis of sagittal spinal shapes, Roussouly groups 3 and 4 showed more severe scoliosis with higher lumbar lordosis and thoracic kyphosis (P0.05). In addition, Roussouly group 1 demonstrated a significantly higher incidence of low-grade scoliosis, whereas groups 3 and 4 had a higher incidence of high-degree scoliosis by cross-relation analysis (P0.05).A significant relationship exists between sagittal spinal shape and coronal curvature in scoliosis. Understanding the biplanar shapes of scoliosis may be helpful to the surgeons.
- Published
- 2017
156. Estimation of Channel Correlation for Massive MIMO Signal Transmission
- Author
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Yong-Suk Byun, Hyoung-Keon Kim, and Yong-Hwan Lee
- Subjects
Channel correlation ,Spatial correlation ,Covariance matrix ,business.industry ,Computer science ,ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS ,MIMO ,Duplex (telecommunications) ,020206 networking & telecommunications ,Data_CODINGANDINFORMATIONTHEORY ,02 engineering and technology ,01 natural sciences ,010104 statistics & probability ,Base station ,Transmission (telecommunications) ,0202 electrical engineering, electronic engineering, information engineering ,Electronic engineering ,0101 mathematics ,Telecommunications ,business ,Computer Science::Information Theory ,Communication channel - Abstract
Conventional channel estimation schemes may require for the use of orthogonal pilot signals for each antenna in frequency-division duplex (FDD) wireless systems. It is a very challenging issue to get channel information with an affordable signaling overhead in massive multi-input multi-output (m-MIMO) FDD transmission environments. The signaling overhead for the channel estimation can be reduced by exploiting the downlink channel correlation matrix (DCCM) of m-MIMO channel. With the use of DCCM, the channel information can be estimated using a reduced number of pilot signals. However, the accuracy of DCCM may seriously affect the estimation performance. In this paper, we consider the estimation of DCCM in m-MIMO transmission environments. Since the distance between a base station and a user is much larger than that between antennas, a set of antenna pairs of equal distance may experience similar spatial correlation due to the far-field effect. We consider the estimation of DCCM by averaging the correlation of these antenna pairs without reception of a large number of pilot signals, significantly reducing the pilot signaling overhead. We also consider the improvement of estimated DCCM by dropping out inaccurate correlation terms. Finally, we verify the proposed scheme by computer simulation.
- Published
- 2017
157. The Enhanced Physico-Chemical and Electrochemical Properties for Surface Modified NiO Cathode for Molten Carbonate Fuel Cells (MCFCs)
- Author
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Keon Kim, Cheol Woo Yi, and Hee Seon Choi
- Subjects
Materials science ,Inorganic chemistry ,Non-blocking I/O ,Surface modified ,General Chemistry ,Electrochemistry ,Cathode ,law.invention ,chemistry.chemical_compound ,chemistry ,law ,Fuel cells ,Surface modification ,Carbonate - Published
- 2014
158. Analysis on Spray Pattern of Airless Tip for Heavy Duty Coating Using Particle Image Velocimetry
- Author
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Dong-Keon Kim, Soon-Hyun Yoon, Seung-Wan Cho, Bonghwan Kim, and Hyo-Sung Choi
- Subjects
Materials science ,Break-Up ,business.industry ,Turbulence ,Structural engineering ,engineering.material ,Radial direction ,Coating ,Particle image velocimetry ,Heavy duty ,engineering ,Composite material ,business ,Intensity (heat transfer) - Abstract
Heavy duty coating is playing an important role in the field of heavy industry in the development of the shipbuilding and plant industries. Heavy duty coating has the very important function of protecting steel under serious corrosive conditions. The airless tip used for heavy duty coating is an essential part that determines the spray pattern of the paint. This research investigated the injection properties of three airless tips(numbers 521, 523, and 525) by using particle image velocimetry(PIV). The velocity and turbulent intensity according to pressure change with each tip type were investigated by using PIV. If the pressure is greater, the turbulent intensity becomes stronger and the break up of particles becomes bigger as the tip number gets smaller. The velocity is the fastest in the center and decreases in the radial direction.
- Published
- 2014
159. A Simple Surface Modification of NiO Cathode with TiO2Nano-Particles for Molten Carbonate Fuel Cells (MCFCs)
- Author
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Hee Seon Choi, Cheol Woo Yi, and Keon Kim
- Subjects
Diffraction ,Materials science ,Non-blocking I/O ,Metallurgy ,Nanoparticle ,General Chemistry ,Homogeneous distribution ,Cathode ,law.invention ,chemistry.chemical_compound ,Chemical engineering ,chemistry ,law ,Surface modification ,Carbonate ,Spectroscopy - Abstract
modified powder is almost same as that of the pristine NiOpowder. The existence of Ti is identified through energydispersive spectroscopy (EDS) and these data demonstratethe homogeneous distribution of Ti without severe agglome-ration after annealing.The structural change in the modified powders after surfacemodification was investigated by X-ray diffraction (XRD).Figure 2 shows XRD data of the samples annealed at 650
- Published
- 2014
160. Proposal for Safety Inspection of Multiple Dwellings in the Era of Sustainability
- Author
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Cheonghoon Baek, Sang-Hoon Park, and Dong-Keon Kim
- Subjects
Numerical Analysis ,Computational Theory and Mathematics ,State (polity) ,Applied Mathematics ,media_common.quotation_subject ,Sustainability ,Business ,Analysis ,Construction engineering ,Computer Science Applications ,media_common - Abstract
In this paper, methods to institute a sustainable safety inspection system for e xtent multiple dwellings in Korea are presented. The results of the study are summarized below. First, on the basis of a study on the safety inspection systems for multiple dwe llings in Japan and the United States, the state of the safety inspection systems and the policies for multiple dwellings in Korea is exa mined. Subsequently, the weaknesses of the Korean safety inspection systems and the need to revise them are discussed. Second, the housing circumstances in Korea, Japan, and the United States are analyzed and compared, including laws on safety inspection for multiple dwellings, targets and items of inspection, qualifications for inspection, building history systems, and qualified professionals for safety inspection. On the basis of the analysis and com parison, the differences between the systems of the three nations and the issues that need to be introduced in Korea are presented. Third, based on the safety inspection experiences in Japan and the United States, new directions of safety inspection and methods to enhance current systems for multiple dwellings in Korea are proposed.
- Published
- 2014
161. Gossypol Suppresses Growth of Temozolomide-Resistant Glioblastoma Tumor Spheres
- Author
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Ji Hoon Jeon, Hyonchol Jang, Dong Keon Kim, Seok Gu Kang, Sang Won Kang, Soo-Youl Kim, Jin Kyoung Shim, Hee Yeon Kim, and Byung Il Lee
- Subjects
Male ,0301 basic medicine ,Programmed cell death ,Combination therapy ,Cell Survival ,Cell ,lcsh:QR1-502 ,Apoptosis ,Biochemistry ,Article ,lcsh:Microbiology ,bcl2 ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Temozolomide ,Tumor Cells, Cultured ,medicine ,Humans ,Antineoplastic Agents, Alkylating ,neoplasms ,Molecular Biology ,Cell Proliferation ,Membrane Potential, Mitochondrial ,Contraceptive Agents, Male ,glioblastoma ,temozolomide resistance ,medicine.disease ,Combined Modality Therapy ,gossypol ,nervous system diseases ,Lymphoma ,Molecular Docking Simulation ,Metabolic pathway ,030104 developmental biology ,medicine.anatomical_structure ,chemistry ,Drug Resistance, Neoplasm ,dehydrogenase ,Gossypol ,030220 oncology & carcinogenesis ,Cancer research ,Drug Screening Assays, Antitumor ,medicine.drug ,Glioblastoma - Abstract
Temozolomide is the current first-line treatment for glioblastoma patients but, because many patients are resistant to it, there is an urgent need to develop antitumor agents to treat temozolomide-resistant glioblastoma. Gossypol, a natural polyphenolic compound, has been studied as a monotherapy or combination therapy for the treatment of glioblastoma. The combination of gossypol and temozolomide has been shown to inhibit glioblastoma, but it is not clear yet whether gossypol alone can suppress temozolomide-resistant glioblastoma. We find that gossypol suppresses the growth of temozolomide-resistant glioblastoma cells in both tumor sphere and adherent culture conditions, with tumor spheres showing the greatest sensitivity. Molecular docking and binding energy calculations show that gossypol has a similar affinity to the Bcl2 (B-cell lymphoma 2) family of proteins and several dehydrogenases. Gossypol reduces mitochondrial membrane potential and cellular ATP levels before cell death, which suggests that gossypol inhibits several dehydrogenases in the cell&rsquo, s metabolic pathway. Treatment with a Bcl2 inhibitor does not fully explain the effect of gossypol on glioblastoma. Overall, this study demonstrates that gossypol can suppress temozolomide-resistant glioblastoma and will be helpful for the refinement of gossypol treatments by elucidating some of the molecular mechanisms of gossypol in glioblastoma.
- Published
- 2019
162. Carbon nanotube-based strain sensor for structural health monitoring
- Author
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Shin-Won Kang, Daewoong Jung, Jae-Keon Kim, Maeum Han, Jong Pil Yun, Gil S. Lee, and Ye-il Choi
- Subjects
Materials science ,Physics and Astronomy (miscellaneous) ,law ,General Engineering ,General Physics and Astronomy ,Nanotechnology ,Structural health monitoring ,Carbon nanotube ,Strain sensor ,law.invention - Published
- 2019
163. Low-Cost Colorimetric Textile Gas Sensor for Detection of Hydrogen Sulfide
- Author
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Junyeop Lee, Jae Keon Kim, and Daewoong Jung
- Abstract
Hydrogen sulfide(H2S) is a highly toxic, corrosive, flammable gas. It is produced from the microbial breakdown of organic matter in the absence of oxygen. H2S also occurs naturally in volcanic gases, hot springs, and industrially in waste water treatment, gas drilling, tanneries, etc. H2S is colorless, and it reacts with metal ions to form metal sulfides, which are insoluble. For example, lead(II) acetate, soluble white crystalline, is converted lead(II) sulfide(PbS) which is black colored insoluble solid when it exposed to H2S. Recently, there has been development in field of semiconducting metal-oxide sensors [1], optical sensors [2], electrochemical sensors [3] to real time, portable detection of H2S. This study aims to use of a cost-effective, easy to fabricate chemical textile sensor for the detection of H2S. Lead(II) acetate was chosen because of its white color crystalline and solubility. It is easy to recognize changes in color after exposure to harmful gas, H2S. Lead(II) acetate printed textile gas sensor demonstrated dark brown color upon exposure to the H2S under 1 ppm whereas no response was observed to other gas and ambient conditions. And the textile gas sensor was placed between a LED and photodiode to readout the electrical signal. Resistance of photodiode was increased with color change (H2S exposure). It can be noted that extremely small concentrations of H2S even under 1 ppm can be recognized and measured by naked eye and photodiode. This textile-based sensor is disposable, cost effective, easy to fabricate, and simple approach to detect H2S. [1] G. F. Fine et al., “Metal Oxide Semi-Conductor Gas Sensors in Environmental Monitoring,” Sensors, vol. 10, no. 6, pp. 5469–5502, Jun. 2010. [2] K. Hayashi, “Optical Chemical Sensor,” IEEJ Trans. Sensors Micromachines, vol. 135, no. 8, pp. 299–304, 2015. [3] K. E. Kramer, S. L. Rose-Pehrsson, M. H. Hammond, D. Tillett, and H. H. Streckert, “Detection and classification of gaseous sulfur compounds by solid electrolyte cyclic voltammetry of cermet sensor array,” Anal. Chim. Acta, vol. 584, no. 1, pp. 78–88, 2007. Figure 1
- Published
- 2019
164. Carbon Nanotube Compositie Based Sensor for Detecting Hydrogen Molecules
- Author
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Junyeop Lee, jae Keon Kim, Samhwan Kim, and Daewoong Jung
- Abstract
Accuracy and precise measurement of gas values is crucial for recognizing many critical biological and physical signs, as gas values present significant signals for monitoring chemistry, biology, environments and medical industries. Many sensing materials such as metal compounds, composite, nanowires, and polymers, for detecting gas have been investigated, and the merits and demerits of each have been reported [1,2]. Recently, carbon-based nanomaterials, including zero-dimensional fullerenes, one-dimensional carbon nanotubes (CNT), and two-dimensional graphene, have shown probable in gas sensor applications. Many prior works have reported their superior properties, including higher electrical conductivity, mechanical durability and chemical stability, and a larger surface area.In particularly, CNTs are well known material for sensor applications due to their stable graphite configuration, structural endurance under chemical/physical treatment processes, and mechanical characteristics. Moreover, lots of efforts to realize CNTs as chemical sensor material were performed by many groups previously [3]. They reported that the concentrations of electrons and holes in CNTs play important role in sensitivity of the CNT-based gas sensor. However, although many techniques were introduced to fabricate the CNT-based gas sensors, such device manufacturing processes were intricate and have limited repeatability and reliability, which makes hard them to be commercialized.The CNT yarn was introduced, reported and characterized previously by group using simple dry spinning method [4]. The CNT yarn has good electrical property with a high conductivity, and flexible structural property, and chemical stability. In this work, we develop the ability of CNT yarn for detecting hydrogen and carbon monoxide concentrations. Furthermore, we demonstrate that metal nanoparticles on the surface of CNT yarn highly affect the sensitivity of the CNT yarn-based gas sensor. Therefore, this study focused on the analysis and characteristics of the gas sensor using binary composite as gas sensor. References [1] Liu et al., Sensors 12, 9635 (2012). [2] Varghese et al., Sens. Actuators. B 218, 160 (2015). [3] Llobet et al., Sens. Actuators. B 179, 32 (2013). [4] Hwang et al., Puller. Nanotub. Car. N. 24, 305 (2016).
- Published
- 2019
165. A CO gas sensor based on Pt-loaded carbon nanotube sheets
- Author
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Shin-Won Kang, Daewoong Jung, Jae-Keon Kim, Gil S. Lee, and Maeum Han
- Subjects
010302 applied physics ,Materials science ,Nanocomposite ,Physics and Astronomy (miscellaneous) ,Temperature sensing ,High conductivity ,General Engineering ,General Physics and Astronomy ,chemistry.chemical_element ,Nanoparticle ,Carbon nanotube ,01 natural sciences ,law.invention ,chemistry.chemical_compound ,chemistry ,law ,0103 physical sciences ,Composite material ,Platinum ,Carbon monoxide - Abstract
This paper proposes a simple and efficient method to develop a nanocomposite by depositing platinum (Pt) nanoparticles on a carbon nanotube (CNT) sheet, and experimentally verifies the applicability of the proposed nanocomposite as a reliable and sensitive carbon monoxide (CO) gas sensor that operates at room temperature. A Pt-CNT nanocomposite shows improved CO gas sensing properties compared with the pristine CNT sheet. Owing to its large surface area and high conductivity, a CNT sheet exhibits improved sensitivity and fast response and recovery times. Based on the Pt-CNT nanocomposite implemented by the proposed method, we fabricated a Pt-CNT sheet-based CO gas sensor operating at room temperature and experimentally verified its stable and reliable room temperature sensing properties and excellent structural flexibility.
- Published
- 2019
166. Improved Performance of Carbon Nanotube Based Strain Sensor
- Author
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jae Keon Kim, Junyeop Lee, and Daewoong Jung
- Abstract
Strain sensor has been used in variety of industrial applications for structural healthy monitoring and biological signal analysis. The fabrication of a highly sensitive strain sensors are underwent many complex and delicate processes, as many fabrication parameters and conditions must be keep equilibrium to achieve good sensor performance, such as high linearity and sensitivity, stable responsivity, fast response time, mechanical durability, and signal processing steps [1]. Carbon based-nano materials such as fullerene, carbon nanotube (CNTs), and graphene have been considered as sensing materials for optical sensor, chemical sensor, physical sensor and environmental sensor, which possess their own strengths and weakness. Especially, CNTs have been widely employed as sensing species for strain/pressure, gas, temperature, and humidity sensor in recent years. CNT-based sensors were generally fabricated by transferring the individual or bundles of CNTs to the substrates using spin-coating, spraying, dip coating, and inkjet printing methods [1-2]. On the other hand, spin-capable CNTs were reported previously, which simply make transparent conductive CNT webs, ribbon or yarns. The spin-capable CNT forest can give an easy and effective way to fabricate highly-aligned CNT yarn with high flexibility and a electrical conductivity for sensor applications [1-3]. In this paper, we present performance of the CNT yarn based strain sensor. Especially, CNT yarn was associated with stretchable polymers to apply tensile and compressive force. The experimental results reveal that CNT yarn with elastic rubber can be stretch up to 300 %. References Jung et al, J. Vac. Sci. Technol. 32 (2014), 04E107. Han et al. Microelectron. Eng., 168 (2017), 50-54. Jung et al., J. Sensors. Sci. & Tech,. 22 (2013), 315-320
- Published
- 2019
167. Development of High Pressure Pump of 50MPa class for Ship Painting
- Author
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Dong-Keon Kim and Soon-Kyung Kim
- Subjects
Engineering ,Piston pump ,business.industry ,High pressure ,Rotodynamic pump ,Flow (psychology) ,Mechanical engineering ,business - Abstract
In this study, numerical simulations and performance evaluation has been carried out to investigate performance characteristics of air-type high pressure piston pump. ANSYS and CFX were applied for analyzing the structure and flow behavior of air-type high pressure piston pump, respectively. The performance evaluation of high pressure piston pump was performed experimentally, the results were compared with simulation. It was found that the freezing phenomenon was improved by 20% and the pressure fluctuation decreased by 50%, compared with the previous pump.
- Published
- 2013
168. Characteristics and Lethality of Suicide Attempters by Age Group in Korea: Retrospective Single-Centered Study.
- Author
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Chang-Wan Kim, Yoon-Hee Choi, and Keon Kim
- Abstract
Background: Suicide is a major cause of death worldwide. While studies have been conducted on the predictors of suicide behaviors, these have not covered how lethality and the various predictors differ by age. We explored these age differences in the present study. Methods: We retrospectively reviewed the medical records of suicidal patients in the emergency department (ED) of a university hospital in Seoul, South Korea, between September 2017 and August 2018.We extracted participants' data fromthe National Emergency Department Information System of Korea and their individual electronic medical records (EMRs), including demographic information (e.g., age, gender), details of their ED visit (e.g., suicide method), and medical history (e.g., physical illness, alcohol co-ingestion).We also used EMR data to complete the Risk-Rescue Rating Scale (RRRS). Results: Of the 499 patients referred to the ED for suicide attempts, 427 were analyzed. We found that while younger participants were more likely to have repeated attempts, older participants' attempts were more likely to be fatal (e.g., higher RRRS risk scores and lower accessibility-to-rescue scores). After adjusting for demographics, older participants showed significantly higher scores on RRRS risk, impaired consciousness, and treatment required than younger participants. Conclusion: Our findings clarified the characteristics of high-risk suicide attempters based onage, which could influence suicide-prevention policies (e.g., younger people tend to repeat suicide attempts, and thus may require continued surveillance). However, as older adults showed higher lethality and were more difficult to save, they may require suicide prevention coupled with social support interventions. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
169. Male pseudohermaphroditism with os clitoris in three dogs.
- Author
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Keon Kim, Sang-ho Lee, Chang-ho Son, Sang-ik Park, and Chang-min Lee
- Subjects
CLITORIS ,INTERSEXUALITY ,GENITALIA ,FEMALE reproductive organs ,DOG breeds ,VETERINARY hospitals - Abstract
Two American Cocker Spaniels and one Bichon Frise were presented to our veterinary teaching hospital with an enlarged clitoris. Diagnostic imaging showed that the structure was composed of bony material. Exploratory laparotomy revealed uterine-like structures and testes which had an epididymis unilaterally. Surgical removal of internal genitalia, gonads and protruded clitoris were performed well. Histological evaluation revealed; inactive testes, female internal genital tracts with ambisexual ductal remnants, and prominent ossification in the clitoris. All 3 cases were diagnosed with male pseudohermaphroditism. In author's knowledge, this is the first report in Bichon Frise dog with os clitoris and also, it describes not common cases in small dog breeds with os clitoris. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
170. Advances in Civil, Architectural, Structural and Constructional Engineering : Proceedings of the International Conference on Civil, Architectural, Structural and Constructional Engineering, Dong-A University, Busan, South Korea, August 21-23, 2015
- Author
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Dong-Keon Kim, Jongwon Jung, Junwon Seo, Dong-Keon Kim, Jongwon Jung, and Junwon Seo
- Subjects
- Material sciences--Congresses, Civil engineering--Congresses, Structural analysis (Engineering)--Congresses
- Abstract
The ICCASCE 2015 conference covers a wide range of fields in science and engineering innovation and aims to bring together engineering technology expertise. Scientists, scholars, engineers and students from universities, research institutes and industries all around the world gathered to present on-going research activities. This proceedings volume
- Published
- 2016
171. Mobi-Kids Study: Exposure Assessment of Electromagnetic Radiation from Mobile Phones I. Analysis on Exposure Types
- Author
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Hyung-Do Choi, Byungje Lee, Jae-Sang So, Ae-Kyoung Lee, Hyunho Wi, Dae-Keon Kim, and Yonghyun Yoon
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Engineering ,Exposure level ,Human exposure ,business.industry ,Mobile phone ,Phone ,business ,Telecommunications ,human activities ,Exposure assessment - Abstract
Four countries are participating in exposure assessment for Mobi-Kids Study. Each country evaluates RF and ELF exposure from mobile phones considering telecommunication system and environment in the corresponding area. The results will be used to determine accumulation exposure level of each subject in case and control groups to assess the potential carcinogenic effects of childhood and adolescent exposure to radio frequency(RF) and extremely low frequency( ELF) from mobile phones on the central nervous system. This paper analyzes exposure types of mobile phones which have been used in Korea for about 10 years, based on Mobi-Kids protocol. It includes investigation of mobile phone models released in the domestic market, design of numerical phone models to represent each exposure type, and measurement of ELF radiation from mobile phones.
- Published
- 2013
172. Cyclic damage model for E-shaped dampers in the seismic isolation system
- Author
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Jong Wan Hu, Gary F. Dargush, and Dong Keon Kim
- Subjects
Engineering ,Entropy production ,business.industry ,Mechanical Engineering ,Subroutine ,Structural engineering ,Plasticity ,Dissipation ,Finite element method ,Damper ,Mechanics of Materials ,Component (UML) ,Seismic isolation ,business - Abstract
The objective of this study is to apply a constitutive damage model for cyclic response of E-shaped dampers as well as metal and metallic plate dampers in order to be used in more broad areas such as material and component levels. The seismic isolation system used as sliding bearings and metallic dampers undergoes almost elastoplastic behavior due to seismic excitation. Accordingly, a two surface damage model is applied to understand inelastic behavior and to evaluate the potential damaged state of E-shaped dampers in the seismic isolation system. This damage model is originally formulated through a thermodynamic approach based on the entropy production equation. The cyclic damage model proposed in this study can be implemented into a user subroutine in the finite element (FE) software ABAQUS. Finally, the numerical results for E-shaped energy dissipation devices in the seismic isolation system are compared with the experimental test results so as to check the validity of the proposed model.
- Published
- 2013
173. A simple novel endoscopic successive suture device: a validation study for closure strength and reproducibility
- Author
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Hyuk Soon Choi, Dae Hie Hong, Keon Kim, Bora Keum, Young-Joong Kim, Hoon Jai Chun, Yongnam Song, and Byung Gon Kim
- Subjects
Gastrostomy ,medicine.medical_specialty ,Reproducibility ,Validation study ,Endoscope ,Swine ,business.industry ,Stomach ,Suture Techniques ,Perforation (oil well) ,Gastroenterology ,Reproducibility of Results ,Endoclip ,Surgery ,Suture (anatomy) ,Closure (computer programming) ,Surgical technology ,Gastroscopy ,Pressure ,Animals ,Medicine ,business ,Biomedical engineering - Abstract
Background and study aims: Endoscopic surgical technology has been developing rapidly. Although several successful endoscopic closure devices have already been introduced, only a few of them have demonstrated improvements in closure strength and reproducibility over conventional endoscopic clip closures or hand sutures. The objective of this study was to test the feasibility of a novel successive suturing device (SSD) by measuring closure strength and reproducibility. Material and methods: Porcine stomach models were used in this study. Endoclips, full-thickness hand sutures, and the novel SSD sutures were used to close a perforation in the stomach wall, with 10 stomachs being tested for each closure method. Endoclips and SSD sutures were performed using a two-channel endoscope, and the hand sutures were performed from outside of the stomach wall. Air leakage pressure was measured to determine the closure strength and reproducibility of each method. Results: The mean air leakage pressure of the SSD closure was 62.7 ± 8.2 mmHg. SSD-treated stomachs exhibited significantly greater air leakage pressure than Endoclip-treated stomachs. The standard deviation of bursting pressure in SSD stomachs was found to be significantly smaller than that of hand-sewn stomachs but was not different from that of Endoclip stomachs. Conclusions: The consistent closure strength of SSD stomachs demonstrated the reliability and reproducibility of this new closure method. These promising results in closure strength and reproducibility suggest the feasibility of the proposed device for clinical applications.
- Published
- 2013
174. Numerical Study of Large Deformation Problem of Nonlinear Viscoplasticity
- Author
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Dong Keon Kim and Jong Wan Hu
- Subjects
Nonlinear system ,Large deformation ,Materials science ,Viscoplasticity ,Continuum mechanics ,business.industry ,Dynamic loading ,Damage mechanics ,Constitutive equation ,General Engineering ,Sensitivity (control systems) ,Structural engineering ,business - Abstract
Large deformation problem under dynamic loading has been an issue for mechanical engineer and researcher who study continuum mechanics because of its complex behavior. This study focuses on a large deformation problem based on nonlinear viscoplasticity. Therefore, the Johnson-Cook constitutive model and the Zerilli-Armstrong constitutive model are used to analyze and to understand this stretch example under dynamic loading. Numerical results for stretch example using both constitutive models were compared with the results from ABAQUS/Explicit that considered mesh sensitivity analysis, and were then applied to model failure processes of OFHC copper, with consideration of geometric nonlinearity based on concepts of progressive damage mechanics. This approach helps us to understand and to predict the behavior of large deformation and to perform damage failure analysis.
- Published
- 2013
175. A cyclic two-surface thermoplastic damage model with application to metallic plate dampers
- Author
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Dong-Keon Kim, Cemal Basaran, and Gary F. Dargush
- Subjects
Simple shear ,Materials science ,business.industry ,Entropy production ,Subroutine ,Damage mechanics ,Thermal ,Constitutive equation ,Structural engineering ,Dissipation ,business ,Civil and Structural Engineering ,Damper - Abstract
The objective of this study is to develop a new constitutive model for cyclic response of metals with much broader applicability. Accordingly, a two-surface damage thermoplasticity model is proposed to understand inelastic behavior and to evaluate a potential damaged state of the metals. This model, which derived from small strain theory, is formulated through a thermodynamic approach to damage mechanics based on entropy production. A simple shear problem was utilized to examine several effects of this model, such as fatigue by cyclic loading and temperature, and to allow for the thermal effects on metals. Following this, the proposed cyclic damage model is implemented as a user subroutine in the finite element software ABAQUS. Finally, numerical results of energy dissipation devices are compared with experimental data for validity of this model.
- Published
- 2013
176. A Rate Dependent Plasticity Model under Cyclic Loading of Metals
- Author
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Gary F. Dargush and Dong-Keon Kim
- Subjects
Materials science ,Computer simulation ,Viscoplasticity ,business.industry ,Cyclic plasticity ,Rate dependent ,Cyclic loading ,Structural engineering ,Transient (oscillation) ,Plasticity ,business ,Excitation - Abstract
In real world applications, the response of structures may be dependent on the rate of loading and thus can be affected by transient loading, especially when the rate of loading is significant. In such situations, the rate of loading may become a major issue to understand structures during earthquake excitation or under blast or high velocity impact. In some cases, the rate effect on structures under strong earthquake excitation cannot be ignored when attempting to understand inelastic behavior of structures. Many researchers developed the constitutive theories in cyclic plasticity and viscoplasticity. In this study, numerical simulation by cyclic visocoplasticity models is introduced and analyzed. Finally, the analytical results are compared with experimental results as a means to evaluate and verify the model.
- Published
- 2013
177. A Research on the Transmission and Variation of Tales to Build Korean Yadam Computer Aided Digital Archive
- Author
-
Dong Keon Kim and Woon Ho Choi
- Subjects
World Wide Web ,Variation (linguistics) ,Jaccard index ,Relation (database) ,Computer science ,Similarity (psychology) ,Pairwise comparison ,General Medicine ,Genealogy - Abstract
In this paper, the transmission and variation of tales between Yadamjip's was investigated. Yadamjip is a collection of Yadam, which is a tale of unofficial histories. The data was compiled from 12 books of Yadamjip and the number of tales used in this research is 2,144. The pairwise comparison of 2,144 tales to each other was committed and the transmission and variation of Yadamjip is inferred by computational clustering and text mining methods from the similarity of tales in each Yadamjip. Among the 12 Yadamjip's., it is revealed that there are three major categories of Yadamjip only with respect to the transmission relation. Especially, GIMUN (NL), GIMUM (YS), HAEDONG, CHEONGGU, DONGPAE, GYESEO were revealed to share various tales with trivial or minor variation.
- Published
- 2013
178. Estimating Personal Exposures to Air Pollutants in University Students Using Exposure Scenario
- Author
-
Wonho Yang, Dong-Keon Kim, Sunshin Kim, Sung-Sam Kim, and Ga-Yeon Hong
- Subjects
Pollutant ,Internet cafe ,Air pollutants ,Environmental health ,Environmental engineering ,Environmental science ,Hazardous air pollutants ,Exposure assessment - Abstract
Studies evaluating the health effects of hazardous air pollutants assume that people's exposure to typical pollutant level is the same as specific regional pollutant level. However, depending on social and demographic factors, time-activity pattern of people can vary widely. Since most people live in indoor environments over 88% of the day, evaluating exposure to hazardous air pollutants is hard to characterize. Objective of this study was to estimate the exposure levels of university students of NO 2, VOCs(BTEX) and PM 10 using the scenarios with time-activity pattern and indoor concentrations. Using data from time-use survey of National Statistical Office in 2009, we investigated time-activity pattern of university students and hourly major action. A total of 1,057 university students on weekday and 640 on weekend spent their times at indoor house 13.04 hr(54.32%), other indoors 7.70 hr(32.06%), and transportation 2.36 hr(9.83%). Indoor environments in which university students spent their times were mainly house and school. Air pollutants concentrations of other indoor environments except house and school such as bar, internet cafe and billiard hall were higher than outdoors, indicating that indoor to outdoor ratios were above 1. According to three types of exposure scenarios, exposure to air pollutants could be reduced by going home after school.
- Published
- 2013
179. Investigation of the physical and the optical properties of various base solvents for the liquid scintillator in a neutrino detector
- Author
-
In Sung Yeo, Sook Hyung Song, Bong Keon Kim, Kyung Kwang Joo, and Sun Heang So
- Subjects
Light transmission ,Materials science ,Physics::Instrumentation and Detectors ,business.industry ,Base (geometry) ,General Physics and Astronomy ,Scintillator ,Condensed Matter::Soft Condensed Matter ,Optics ,Neutrino detector ,Neutrino ,business ,Absorption (electromagnetic radiation) ,Refractive index - Abstract
Various liquid scintillators are commonly used in neutrino experiments. If successful neutrino experiments are to be performed over several years, using stable solvents with the capability of mass production in the liquid scintillator is one of the key requirements. We investigate the various physical and optical properties, absorption, light transmission, light output, density, index of refraction, water content, etc., of the solvents used in neutrino detectors. In addition, safety for the environment and humans needs to be taken in consideration. In this paper, the preparation and the various characteristics of the solvents used for the liquid scintillator are summarized and reported.
- Published
- 2013
180. Development of a gadolinium-loaded LAB-based aqueous scintillator for neutrino detection
- Author
-
Bong Keon Kim, Sook Hyung Song, Kyung Kwang Joo, In Sung Yeo, and Sun Heang So
- Subjects
chemistry.chemical_classification ,Quantitative Biology::Biomolecules ,Scintillation ,Aqueous solution ,Physics::Instrumentation and Detectors ,Gadolinium ,Radiochemistry ,General Physics and Astronomy ,chemistry.chemical_element ,Scintillator ,Chemical reaction ,Condensed Matter::Soft Condensed Matter ,Solvent ,Neutrino detector ,chemistry ,Condensed Matter::Strongly Correlated Electrons ,Physics::Chemical Physics ,Alkyl - Abstract
A gadolinium (Gd) complex with carboxylic acid was synthesized by using a neutralization chemical reaction. Gd (0.5%) was doped into a liquid scintillator by using a solvent-solvent extraction under controlled pH. Linear alkyl benzene (LAB) was used as a scintillation solvent. We measured several important physical and optical properties. The preparation, the synthesis procedures and the characterization of the resulting gadolinium-loaded, LAB-based, liquid scintillator are described in this paper.
- Published
- 2013
181. Bracing Systems for Seismic and Wind Performance of Tall Buildings
- Author
-
Jong Wan Hu and Dong Keon Kim
- Subjects
Earthquake scenario ,Engineering ,Earthquake engineering ,Seismic hazard ,Earthquake simulation ,business.industry ,Seismic loading ,General Engineering ,Urban seismic risk ,Seismic retrofit ,Mitigation of seismic motion ,Structural engineering ,business - Abstract
Occurrence of frequency of earthquakes around the world has been increased including Sendai earthquake in Japan and magnitude of earthquake has also increased. Recently, many tall buildings using local seismic codes can be exposed to the risk of an earthquake and wind. Also, some buildings, which was planned to be built, were foundered as a result of lack of finance. Therefore, for tall buildings, structural safety such as earthquake and wind resistant performance, and financing issue are very important to progress the huge project. So we need to find another optimum alternative other than damping devices and base isolation system. In this study, four types of test specimens are used, which are fifty-story base tall building, tall building that was reinforced with diagonal brace, x-brace, and Chevron brace. And all of these cases, are subjected to the seismic load and wind load, finally analyzed and compared for seismic and wind performances.
- Published
- 2013
182. Determination of Fluorescent Whitening Agents in Paper Materials by Ion-Pair Reversed-Phase High-Performance Liquid Chromatography
- Author
-
Jeong Soo Kim, Do Hwan Kim, and Keon Kim
- Subjects
Chromatography ,Chemistry ,Calibration curve ,Phase (matter) ,Ion pair chromatography ,Analytical chemistry ,General Chemistry ,Ion pairs ,Fluorescence ,High-performance liquid chromatography ,Citrate buffer ,Whitening Agents - Abstract
A simple method was developed for the analysis of seven stilbene-type fluorescent whitening agents (FWAs) in paper materials by ion-pair reversed-phase high-performance liquid chromatography with fluorescence detection. These stilbene-type FWAs included two disulfonate, two tetrasulfonate, and three hexasulfonate compounds. After optimization of chromatographic conditions, the FWAs were satisfactorily separated using a reversed-phase column (RP-18) with the following isocratic mobile phase: methanol-water (60:40) containing 17.5 mM TBABr and 10 mM citrate buffer (pH = 7.0). The calibration plot was linear in the range from 5 to 500 ng/mL for two disulfo-FWAs and from 1 to 500 ng/mL for the other five FWAs. Precision levels of the calibration curve as indicated by RSD of response factors were 1.2 and 8.1%. Limits of quantitation (LOQ) ranged from 1.2 to 11 ng/mL.
- Published
- 2012
183. Advanced Engineering and Technology
- Author
-
Dong Keon Kim, Jong Wan Hu, Jong Won Jung, Jun Won Seo, Dong Keon Kim, Jong Wan Hu, Jong Won Jung, and Jun Won Seo
- Subjects
- Mechanical engineering--Congresses, Technology--Congresses, Materials--Congresses
- Abstract
Selected, peer reviewed papers from the International Conference on Advanced Engineering and Technology (ICAET 2014), December 19-21, 2014, Incheon, South Korea
- Published
- 2015
184. Advances in Civil, Architectural, Structural and Constructional Engineering
- Author
-
Jongwon Jung, Dong-Keon Kim, and Junwon Seo
- Subjects
Engineering ,business.industry ,Science and engineering ,business ,Civil engineering ,Construction engineering ,Range (computer programming) - Abstract
The ICCASCE 2015 conference covers a wide range of fields in science and engineering innovation and aims to bring together engineering technology expertise. Scientists, scholars, engineers and students from universities, research institutes and industries all around the world gathered to present on-going research activities. This proceedings volume
- Published
- 2016
185. Structures, building performance study and power energy
- Author
-
Jongwon Jung, Dong-Keon Kim, and Junwon Seo
- Subjects
Building science ,business.industry ,Computer science ,Electrical engineering ,business ,Energy (signal processing) ,Power (physics) - Published
- 2016
186. Water, irrigation and architectural engineering application
- Author
-
Jongwon Jung, Dong-Keon Kim, and Junwon Seo
- Subjects
Engineering ,business.industry ,Water irrigation ,business ,Civil engineering - Published
- 2016
187. Mechanical and management engineering
- Author
-
Dong-Keon Kim, Junwon Seo, and Jongwon Jung
- Subjects
Engineering ,business.industry ,Management engineering ,business ,Construction engineering - Published
- 2016
188. Numerical investigation on the cyclic behavior of smart recentering clip-angle connections with superelastic shape memory alloy fasteners
- Author
-
Jong Wan Hu, Dong Keon Kim, and Eunsoo Choi
- Subjects
Materials science ,Spring (device) ,business.industry ,Mechanical Engineering ,Mechanical joint ,Numerical analysis ,Ultimate tensile strength ,Shape-memory alloy ,Structural engineering ,Deformation (engineering) ,business ,Displacement (vector) - Abstract
Superelastic shape memory alloy materials have become increasingly prevalent for recentering devices that have the ability to recover their plastic deformation automatically. For this reason, this study proposed new clip-angle connections incorporating superelastic shape memory alloy bolts. Including component spring models, mechanical joint models of steel bolted connections and shape memory alloy bolted connections are created for numerically simulating their cyclic behavior. The numerical analysis results are then compared to each other in terms of ultimate strength, energy dissipation, and permanent deformation. In particular, over 60% of the total displacement was recovered during unloads in case of shape memory alloy bolted connections, indicating that the proposed smart connections display obvious recentering features in their behaviors.
- Published
- 2012
189. Experimental Verification of a Liquid Damper with Changeable Natural Frequency for Building Response Control
- Author
-
Ji-Hun Park, Dong-Ik Kim, Jae-Keon Kim, Kyung-Won Min, Yong-Sik Gil, and Kyu-Seok Hwang
- Subjects
Engineering ,business.industry ,Stiffness ,Natural frequency ,Structural engineering ,Transfer function ,Similitude ,Square (algebra) ,Damper ,Acceleration ,medicine ,Earthquake shaking table ,medicine.symptom ,business - Abstract
This study deals with the experiments of liquid dampers with multi cells whose vertical tubes are divided into several square columns for easily changing natural frequencies. Shaking table test is performed to verify control effectiveness of the dampers which are installed on a building structure. To design liquid dampers, a 64-story building structure is reduced to a SDOF structure with 1/20 of similitude laws based on acceleration. The structure model is made up to adjust its mass and stiffness easily, with separate mass and drive parts. Mass parts indicate real structure`s weights and drive parts indicate real structure`s stiffness with springs and LM guides. Manufactured liquid damper has 18 cells and its natural frequency ranges are 0.65Hz to 0.81Hz. Shaking table test is carried out with one way excitation to compare with only accelerations of a large-scale structure and a structure installed with liquid dampers. Control performance of the liquid damper is expressed by the transfer function from shaking table accelerations to the large-scale structure ones. Testing results show that the liquid damper reduced a large-scale structure`s response by tuned natural frequencies.
- Published
- 2012
190. Inelastic behavior of smart recentering buckling-restrained braced frames with superelastic shape memory alloy bracing systems
- Author
-
Dong-Ho Choi, Jong Wan Hu, and Dong Keon Kim
- Subjects
Cable gland ,Engineering ,Buckling ,business.industry ,Mechanical Engineering ,Framing (construction) ,Braced frame ,Shape-memory alloy ,Structural engineering ,Induced seismicity ,business ,Bracing ,Brace - Abstract
Buckling-restrained braced frames are steadily replacing concentrically braced frames because buckling-restrained brace can yield without buckling when subjected to both tension and compression. Though buckling-restrained brace frames are being widely used as framing structures for construction in high seismicity areas, it is shown that at large strains, a considerable amount of permanent deformation is produced at the support connector between the brace and the frame. This drawback can be overcome by providing recentering capabilities to the braced frame system. By applying the concept of a recentering system to the design of buckling-restrained brace frames, we developed braced frames that incorporate buckling-restrained braces with superelastic shape memory alloy end-support connectors. Owing to the recentering capability, shape memory alloy materials have been used in the place where large deformation may feasibly occur. The primary advantages of the innovative braced frames proposed herein are verified through nonlinear pushover analyses. Analytical frame models are developed to estimate theultimate and residual inter-story drifts. The analysis results suggest that buckling-restrained brace frames with superelastic shape memory alloy bracing systems are more effective in controlling residual inter-story drifts than those with conventional steel bracing systems owing to the inherent self-healing characteristics of superelastic shape memory alloys.
- Published
- 2012
191. Phosphoric Acid-Functionalized Mesoporous Silica/Nafion Composite Membrane for High Temperature PEMFCs
- Author
-
Jong-Won Lee, Cheol Woo Yi, and Keon Kim
- Subjects
chemistry.chemical_compound ,Membrane ,Materials science ,chemistry ,Chemical engineering ,Nafion ,Specific surface area ,Proton exchange membrane fuel cell ,General Chemistry ,Particle size ,Mesoporous silica ,Mesoporous material ,Phosphoric acid - Abstract
The proton exchange membrane fuel cell (PEMFC) has received a great attention as a clean power generator to convert the chemical energy of hydrogen to electric energy electrochemically. It has major advantages for the portable electronic devices and transportation/stationary power systems such as the high power density and high energy efficiency, rapid start-up, etc. One of the most widely used proton exchange membrane is perfluorosulfonic acid (Nafion, DuPont Co.). It has excellent thermal and chemical stability and high proton conductivity below 80 C. However, PEMFC with Nafion membrane shows the poor performance at higher temperature due to the dehydration and low proton conductivity of the membrane. Recently, many studies have been performed to develop proton conducting membrane for operation above 100 C because the high temperature operation of PEMFC has the advantages of low CO poisoning of Pt catalyst and simple thermal and water management. Even if the Nafion composite membranes with incorporation of water retentive and inherent proton conductive fillers have been studied extensively under elevated temperature and low humidity conditions, the proton conductivity of the composite membrane is occasionally lower than the pristine Nafion because the wellconnected ionic domain of the Nafion is deformed by the inorganic fillers. In this paper, we report the physico-chemical and electrochemical properties of the phosphoric acid-functionalized mesoporous silica/Nafion composite membrane. The mesopore of silica increases the water retention capacity more effectively, and the phosphor-silicate has thermally and chemically stable silica networks and the surface-terminated phosphate interacts strongly with the water molecules. Therefore, the phosphoric acid-functionalized mesoporous silica/Nafion composite membrane shows the higher proton conductivities and cell performance than the pristine Nafion at high temperature and low humidity. The morphology and particle size of the prepared inorganic materials were investigated by TEM, and the data are shown in Figure 1. The shape of mesoporous SiO2 is spherical with a diameter of ~45 nm and their pore size is ~5 nm as shown in Figure 1(a). The specific surface area and the mean pore size of the mesoporous SiO2 are 560 m ·g and 4.82 nm, respectively. However, the morphology of the phosphoric acid-functionalized mesoporous SiO2 was quite different from that of pristine one. As shown in Figure 1(b)-(d), the porous structure is destructed and particle size increases as the annealing temperature increases after the mixing of mesoporous SiO2 with phosphoric acid. Figure 1(b) shows the sample heated at 80 C in the vacuum, and the result shows that the porosity of the sample is slightly reduced. With an annealing at 200 C, the morphology change is significant in that the mesopore disappears and large pore is formed. Interestingly, the further annealing above 200 C, the pore completely disappears and their particle size also increases, because of the formation of phosphor silicate through the reaction of silica and phosphoric acid, and the bulk-like phosphor silicate phase is confirmed by XRD (not shown for brevity). In order to elucidate the chemical structure of the prepared
- Published
- 2012
192. Damage Progress of Structural Steel Under Cyclic Loading Using an Elastoplastic Damage Model
- Author
-
Sung-Woo Shin, Gary F. Dargush, and Dong-Keon Kim
- Subjects
General Energy ,Health (social science) ,Materials science ,General Computer Science ,business.industry ,General Mathematics ,General Engineering ,Cyclic loading ,Structural engineering ,business ,General Environmental Science ,Education - Published
- 2012
193. An Elastoplastic Damage Model for Energy Dissipation Devices
- Author
-
Gary F. Dargush and Dong-Keon Kim
- Subjects
General Energy ,Health (social science) ,Materials science ,General Computer Science ,General Mathematics ,General Engineering ,Mechanics ,Dissipation ,General Environmental Science ,Education - Published
- 2012
194. A Two Surface Plasticity Model for Uniaxial Ratchetting of Cyclically Stabilized Material
- Author
-
Gary F. Dargush, Dong-Keon Kim, and Sung-Woo Shin
- Subjects
Surface (mathematics) ,General Energy ,Health (social science) ,Materials science ,General Computer Science ,General Mathematics ,General Engineering ,Plasticity ,Composite material ,General Environmental Science ,Education - Published
- 2012
195. Research Trend of Solid Electrolyte for Lithium Rechargeable Batteries
- Author
-
Keon Kim, Cheol-Woo Yi, and Soon-Sung Suh
- Subjects
Materials science ,Chemical engineering ,Fast ion conductor ,Electrolyte - Abstract
최근 리튬이차전지는 높은 에너지 밀도와 고용량화되어 급속도로 발전하고 있다. 그 중에서도 친환경 수송 장치의 전기자동차가 주목 받고 있는데 이를 위해서는 리튬이차전지의 많은 성능개선이요구된다. 현재 리튬이차전지는 ‘하이브리드 전기자동차 (Hybrid Electric Vehicle, HEV)’에 실제적용되고 있으며 이를 위해서 높은 용량, 긴 수명, 그리고 안전성 확보가 반드시 필요하다. 하지만현재 리튬이차전지에서 리튬이온의 이동을 위해 사용하는 유기전해액의 과열 및 과충전 상태에서폭발의 위험성을 가지고 있기에 높은 안전성을 가진 고체전해질로의 대체가 시급하다. 따라서 본연구에서는 리튬이차전지의 안정성 및 성능 개선을 위한 고체전해질의 연구 동향과 출원된 특허및 논문에 대하여 논의하고자 한다.Abstract : Recently lithium ion secondary batteries (LIB) have rapidly developed because oftheir advantages such as high energy densities and capacities. Among them, an electrical vehiclewhich is the one of the environmental-friendly transportation facilities has been received a greatattention, but, it is needed to overcome several obstacles of the LIB performances. LIB is practicallyadapted to Hybrid Electric Vehicle (HEV), but the issues for high capacities, long life timeand safety should be solved. Moreover, LIBs still have some possibilities of explosion in the caseof overheating of the used organic electrolyte and overcharging of the cell. Hence, it is urgentlyneeded to replace the liquid electrolytes into the solid electrolytes due to the safety issues.Therefore, in this review, we summarized and discussed the research trends of the solid elec-trolyte to solve the concerns of safety and capacity of LIBs and published patents and articles.Keywords: Solid electrolyte, Li-ion battery, All-solid battery, Safety, LISICON, NASICON
- Published
- 2012
196. A two surface plasticity model for the simulation of uniaxial ratchetting response
- Author
-
Gary F. Dargush, Sung Woo Shin, Jong Wan Hu, and Dong Keon Kim
- Subjects
Materials science ,Yield (engineering) ,business.industry ,Mechanical Engineering ,Isotropy ,Bilinear interpolation ,Structural engineering ,Plasticity ,Nonlinear system ,Mechanics of Materials ,Range (statistics) ,Tensor ,business ,Parametric statistics - Abstract
In this study, a two surface plasticity model was developed and used to simulate the uniaxial ratchetting response of CS 1026 steel. Most cyclic plasticity models used in ratchetting simulations are Chaboche-type nonlinear kinematic hardening models, which deal with dynamic recovery terms considering the back stress tensor. This paper describes the ratchetting simulation of steel by the two surface model based on yield theory following both isotropic and kinematic hardening rules in order to obtain enhanced ratchetting response. The parameters used in the simulation were obtained from a parametric study and were determined from the initial range and stabilized range of CS 1026 steel. In addition, the two surface model was validated by comparing the results of a ratchetting simulation with experimentally determined maximum axial strain per cycle. The ratchetting responses obtained from the two surface model are an improved simulation results compared with results from bilinear and kinematic hardening models.
- Published
- 2012
197. Study on the Calculation of International ICT Network Indices
- Author
-
Woo-Soo Jeong and Seung-Keon Kim
- Subjects
Index (economics) ,Broadcasting (networking) ,Ranking ,National brand ,Information and Communications Technology ,Business ,Marketing ,Telecommunications network ,Industrial organization - Abstract
With the development of ICT technology, the broadcasting and communication networks of Korea have been bigger, faster and more reliable and Korea has become one of the leading countries in the ICT industry. Through the international ICT indices, we can see different economies' ICT industry competitiveness at a glance and high ranking in such indices can make national brand image improve. However almost all the existing international ICT indices mainly focused on the telecommunication industry, not on the broadcasting industry. This study thus aims to develop a new index focusing on broadcasting and communication networks. This new index is composed of 3 sectors such as access, usage and environment with different weight respectively and using objective indicators. This study also aims to contribute to improve Korea's national brand image by developing new systematic and effective broadcasting and communication index.
- Published
- 2011
198. The Synthesis and Electrochemical Properties of Lithium Manganese Oxide (Li2MnO3)
- Author
-
Cheol-Woo Yi, Eun-Ah Lee, Hyoree Seo, and Keon Kim
- Subjects
Materials science ,Annealing (metallurgy) ,Inorganic chemistry ,Oxide ,Electrochemistry ,Cathode ,law.invention ,Ion ,chemistry.chemical_compound ,Crystallinity ,chemistry ,Cathode material ,law ,Lithium manganese oxide ,sense organs ,skin and connective tissue diseases - Abstract
The layered lithium-manganese oxide () as a cathode material of lithium ion secondary batteries was prepared and characterized the physico-chemical and electrochemical properties. The morphological and structural changes of MnO(OH) and are closely connected to the changes of electrochemical properties. The crystallinity of is enhanced as the annealing temperature increase, but its capacity is reduced due to the easier structural changes of less crystalline than highly crystalline one. Moreover, the addition of buffer material such as MnO(OH) into cathode causes to reduce the morphological and structural changes of layered and increase the discharge capacity and cycleability.
- Published
- 2011
199. The Synthesis and Electrochemical Properties of Lithium Manganese Oxide (Li2MnO3)
- Author
-
Hyoree Seo, Eun-Ah Lee, Cheol-Woo Yi, and Keon Kim
- Subjects
Materials science ,Inorganic chemistry ,Lithium manganese oxide ,Electrochemistry - Published
- 2011
200. Transcriptomic analysis of Haematococcus lacustris during astaxanthin accumulation under high irradiance and nutrient starvation
- Author
-
Dong Keon Kim, Narae Yim, Jae Han Bae, Choul-Gyun Lee, EonSeon Jin, and Seong Joo Hong
- Subjects
Messenger RNA ,Microarray ,Cell ,Biomedical Engineering ,Bioengineering ,Biology ,Photosynthesis ,Applied Microbiology and Biotechnology ,Transcriptome ,chemistry.chemical_compound ,medicine.anatomical_structure ,Biochemistry ,chemistry ,Astaxanthin ,Complementary DNA ,medicine ,Gene ,Biotechnology - Abstract
In this study, a cDNA microarray was developed from over 60,000 mRNA readings to analyze the expression profiles of transcriptomes of Haematococcus lacustris under astaxanthin-inducing culture conditions, high irradiance and nitrate starvation. Among 20,033 genes on the cDNA microarray, 2,675 genes exhibited a twofold or greater difference in expression. Of these, 1,333 genes were up-regulated and 1,342 genes were down-regulated. A significant decrease in the expression of chlorophyll biosynthesis and light harvesting complex (LHC) related genes were observed under astaxanthin inducing conditions (forming red cyst cells). On the other hand, respirationrelated genes, lipid metabolism-related genes and stress response-related genes were activated in the red cyst cells under stress conditions. These results enabled a better understanding of the cell responses during stress induction of H. lacustris such as photosynthesis, respiration, and some biopathways.
- Published
- 2011
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