A Study on the Behavior of Steel Slag Asphalt Concrete by Temperature

Kyungnam Kim,Shinhaeng Jo,Nakseok Kim,Hyunwook Kim,Hojung Lee 한국도로학회 2018 한국도로학회 학술대회 발표논문 초록집 Vol.2018 No.05

Road construction and maintenance of deteriorated pavement has been continued since industrialization. Demand for aggregate with a good quality has been increasing from limited resources, but it is difficult to supply aggregates smoothly due to environmental protection regulations (Jo et al., 2015). Accordingly, efforts are being made in the road construction industry to utilize industrial products for the purpose of efficient use of resources and environmental preservation. Steel slag which contains a non-reactive CaO is used primarily as a material for embankment and soil covering depending on the expansion and environmental issues. On the other hand, steel slag shows a variety of performance improvements as including increased elasticity factors, increased indirect tensile strength, and improved plastic deformation resistance when handling the expansion issue with sufficient aging processing (Ali et al., 1991, Asi et al., 2007). In this study, the behavior characteristics of the slag asphalt concrete mixture were analyzed according to temperature to encourage the use of steel slag aggregate. Specimens with steel slag showed a higher initial strain than those with natural aggregates. But strain of specimens were nearly similar over the repeated temperature changes. The experimental results for specimens with these characteristics were less likely to cause the performance problems from temperature because the measured strains were relatively small than strain caused from other loads. In conclusion, it is necessary to design and construction process reflecting the behavior characteristics according to temperature to encourage the use of steel slag aggregate.

Characteristics of hot mix asphalt containing steel slag aggregate according to temperature and void percentage

Kim, Kyungnam,Haeng Jo, Shin,Kim, Nakseok,Kim, Hyunwook Elsevier 2018 Construction and Building Materials Vol.188 No.-

<P><B>Abstract</B></P> <P>This study investigated the behavior of hot mix asphalt mixture containing steel slag aggregate (SHMA). Compared to hot mix asphalt mixture containing granite aggregate (GHMA), SHMA increased strains by approximately 15%; however, a void percentage of 4.2% or higher resulted in a strain similar to that of GHMA. Furthermore, the dynamic modulus of SHMA remained higher than that of GHMA because SHMA exhibited favorable aggregate interlock due to its high strength and grain shape. In addition, when the target air void was increased to 4.5%, SHMA showed improvements in rut resistance, tensile strength, and toughness of 121, 110, and 114%, respectively, compared to GHMA.</P> <P><B>Highlights</B></P> <P> <UL> <LI> SHMA demonstrated higher strains than GHMA except at void fractions >4.5%. </LI> <LI> SHMA showed improvement in rut resistance, tensile strength, and toughness. </LI> <LI> Dynamic modulus of SHMA was higher than that of GHMA for all temperatures. </LI> <LI> SHMA can significantly improve performance when appropriately treated. </LI> </UL> </P>

Distal End Force Estimation of Tendon-sheath Mechanism Using a Spring Sheath

Jeonghan Kim,Kyungnam Kim,Yechan Seo,Junyoung Park,Byung Gon Kim,Sooyong Choi,Chanwoo Kim,Daehie Hong 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.24 No.12

Tendon-sheath mechanism (TSM) is often used as a power transmission system in many applications, such as rehabilitation, wearables, and endoscopic surgery robots. It comprises a tendon for transmitting the power and a sheath to guide the tendon. The tendon passes through a narrow and harsh pathway to actuate an end-effector. Consequently, TSM exhibits highly nonlinear force transmission characteristics, resulting in poor control performance. Additionally, attaching and using a force feedback sensor at its distal end is virtually impossible in most applications owing to space constraints and safety concerns. To address these drawbacks, this study proposes a novel sensing spring wire to estimate the distal end force in TSM. Unlike existing methods, the proposed technique does not require complex hyperparameters or modeling and uses only a mechanical part to predict the force. The sensing wire is composed of the sheath. The biocompatibility, simple structure, and small size of the spring sheath facilitate convenient interaction with the existing TSM. Additionally, the spring sheath exhibits the characteristics of a spring, which ensures a linear relationship between the displacement and force. The results indicate that after calibrating the spring sensor, the distal end force can be easily determined using the proximal force despite the absence of an electrical sensor. In situations where the friction is different for each shape, when the force at the distal end was estimated using only the force at the proximal end measured by the sensor, the average RMSE was 75.91mN and the maximum error was 176.52mN. The proposed method verifies that the proximal tension and displacement data are sufficient to estimate the force.

수정땀띠 양상의 물집병변으로 나타난 간 이식 후 급성 이식편대숙주병

배경남 ( Kyungnam Bae ),신기혁 ( Kihyuk Shin ),양민영 ( Minyoung Yang ),이원구 ( Won-ku Lee ),김태욱 ( Taewook Kim ),김훈수 ( Hoon-soo Kim ),고현창 ( Hyun-chang Ko ),김병수 ( Byung Soo Kim ),김문범 ( Moon-bum Kim ),김우일 ( Woo-il 대한피부과학회 2020 대한피부과학회지 Vol.58 No.5

Acute graft-versus-host disease (GVHD) is a common complication associated with bone marrow transplantation. In the rare cases where it occurs after solid organ transplantation, including that of the liver, pancreas, or heart, it often has fatal outcomes. A 50-year old man developed whole-body flaccid vesiculobullous eruption 6 weeks after living donor liver transplantation. Skin biopsy revealed epidermal necrosis with vacuolization of the basal layer and lymphocytic infiltration in the dermis. Stomach erosions were found during an endoscopy, and a concurrent biopsy revealed severe epithelial necrosis. GVHD was diagnosed, with mixed chimerism confirmed using short tandem repeat testing. Immunosuppressive agent therapy was instituted, but the patient expired from hematologic complications and brain damage 6 weeks after treatment initiation. Skin lesions in GVHD generally appear with erythematous maculopapular eruption, but some atypical cutaneous manifestations could be unnoticed by physicians. This report describes miliaria crystallina-like eruption of acute GVHD after liver transplantation. (Korean J Dermatol 2020;58(5):340∼343)

해상풍력 기술의 사회-기술시스템 전환과정에 관한 탐색적 사례연구

김봉균(Kim Bonggyun),김덕영(Kim Dukyoung),김경남(Kim Kyungnam),김동환(Kim Donghwan) 한국기술혁신학회 2014 기술혁신학회지 Vol.17 No.2

새로운 에너지 기술이 기존 사회시스템과 공존하며 확산되는 과정은 저탄소 사회로의 전환을 위해 꼭 필요하지만 어려운 여정이다. 정부주도로 추진되고 있는 서남해 2.5GW 해상풍력사업은 대용량 신재생에너지발전을 중앙전력계통으로 연계하는 것을 목표로 추진되고 있다. 따라서 성공적인 해상풍력발전의 도입을 위해서는 기존 사회기술시스템의 전환도 병행되어야 한다. 본 연구는 다층적 관점과 전략적 니치관리를 방법론으로 해상풍력기술의 니치전략 적용에 대한 에너지 시스템 전환을 분석한다. 연구결과로서 새로운 기술이 기존 레짐(regime) - 환경상황(landscape)과 연계, 소통을 거쳐 성장하는 과정을 다층적으로 분석하고 에너지체제와 신기술의 관계의 변화를 구조화 하였다. 또한 전략적 니치관리 연구를 적용하여 니치실험 착수단계에서 내재하는 장애요인을 진단하고 해상풍력 실증사업 지연의 원인을 파악하였다. 이를 통해 해상풍력 니치기술이 에너지체제와 다양한 제도 속에서 안정적으로 성장할 수 있다는 실천적 시사점을 도출하였다. For the transition to the low carbon society, it is inevitable but difficult journey that the new energy technology spread co-exists with formal social system. The objective of offshore wind power plant that has been implemented by the government is to connect large capacity new renewable energy to the central electric power system. Therefore, for the successful introduction of offshore wind power system, the transition of the formal social technology system should be companied. This study analysis the energy system transition about niche strategy adjustment using Multiple Level Perspectives & Strategic Niche Management. It also multi level analyzes and structuralizes the process that new technology, as a research result, evolves through connecting and communicating with formal regime and landscape. Also, adjusting Strategic Niche Management, it diagnoses the obstructive factors in the initial stage of niche experiment and found the major reasons why offshore wind power test plant had been delayed. Through this study, it reaches to the practical implication that offshore niche technology could grow stably in the energy system and various policies.

Origin of a sharp spectral peak near the critical angle in the spectral power density profile of top-emitting organic light-emitting diodes

Kim, Jiyong,Kang, Kyungnam,Kim, Kyoung-Youm,Kim, Jungho IOP Publishing 2018 Japanese journal of applied physics Vol.57 No.1

<P>We theoretically investigate the origin of the sharp spectral peak near the critical angle in the spectral power density profile of a top-emitting organic light-emitting diode (OLED). On the basis of the point dipole model, spectral power densities of the top-emitting OLED are calculated with respect to the thickness of the capping layer (CPL). Sharp peaks in the spectral power density profile are observed at certain CPL thicknesses near the spectral interface between the radiation-and waveguide-mode regions, which is determined by the critical angle. By calculating the waveguide-mode spatial profile, the sharp peak in the spectral power density profile is identified as the radiation-mode-like waveguide mode, which has a very large evanescent length near the cut-off condition of waveguide modes. By decomposing the total spectral power density into the out-coupled light and absorption loss components, we demonstrate that the sharp spectral peak near the critical angle can enhance the relative power contribution of the absorption loss. (C) 2018 The Japan Society of Applied Physics</P>

Successive and large-scale synthesis of InP/ZnS quantum dots in a hybrid reactor and their application to white LEDs

Kim, Kyungnam,Jeong, Sohee,Woo, Ju Yeon,Han, Chang-Soo IOP Pub 2012 Nanotechnology Vol.23 No.6

<P>We report successive and large-scale synthesis of InP/ZnS core/shell nanocrystal quantum dots (QDs) using a customized hybrid flow reactor, which is based on serial combination of a batch-type mixer and a flow-type furnace. InP cores and InP/ZnS core/shell QDs were successively synthesized in the hybrid reactor in a simple one-step process. In this reactor, the flow rate of the solutions was typically 1 ml min<SUP>−1</SUP>, 100 times larger than that of conventional microfluidic reactors. In order to synthesize high-quality InP/ZnS QDs, we controlled both the flow rate and the crystal growth temperature. Finally, we obtained high-quality InP/ZnS QDs in colors from bluish green to red, and we demonstrated that these core/shell QDs could be incorporated into white-light-emitting diode (LED) devices to improve color rendering performance. </P>

Continuous flow purification of nanocrystal quantum dots.

Kim, Duckjong,Park, Hye Kyung,Choi, Hyekyoung,Noh, Jaehong,Kim, Kyungnam,Jeong, Sohee RSC Pub 2014 Nanoscale Vol.6 No.23

<P>Colloidal quantum dot (QD) purification is typically conducted via repeating precipitation-redispersion involving massive amounts of organic solvents and has been the main obstacle in mass production of QDs with dependable surface properties. Our results show that the electric field apparently affects the streamlining of QDs and that we could continuously collect stably dispersed QDs by the electrophoretic purification process. The purification yield increases as the electric potential difference increases or the flow rate decreases, but reaches an asymptotic value. The yield can be further improved by raising the absolute magnitude of the mobility of QDs with the addition of solvents with high dielectric constants. The continuous purification process sheds light on industrial production of colloidal nanomaterials.</P>

Fabrication of periodic nanoparticle clusters using a soft lithographic template

Kim, Dae Seok,Honglawan, Apiradee,Kim, Kyungnam,Kim, Mun Ho,Jeong, Sohee,Yang, Shu,Yoon, Dong Ki The Royal Society of Chemistry 2015 Journal of Materials Chemistry C Vol.3 No.18

<▼1><P>A novel fabrication method has been developed for the preparation of a periodic array of nanoparticle clusters (NPCs) using a sublimable liquid crystal (LC) material.</P></▼1><▼2><P>A novel fabrication method has been developed for the preparation of a periodic array of nanoparticle clusters (NPCs) using a sublimable liquid crystal (LC) material. The defect structures of the LC film provide the specific topographical confinement to trap nanoparticles (NPs) and assemble the NPs to generate NPCs during thermal annealing. This system shows a simple regulation of the size of NPCs by varying the concentration of the NP-suspension. Additionally, an illumination system using quantum dots (QDs) is fabricated using the manipulation method reported here.</P></▼2>

Design and synthesis of photostable multi-shell Cd-free nanocrystal quantum dots for LED applications

Kim, Kyungnam,Han, Chang-Soo,Jeong, Sohee The Royal Society of Chemistry 2012 Journal of materials chemistry Vol.22 No.40

<P>Multi-shell Cd-free nanocrystals were designed such that (1) the outer-most shell was free of reactive sulfide to prevent corrosion (2) the position of the band-edge emission remained unchanged during multi-shell coating. The photoluminescence and photostability were markedly enhanced and allowed the fabrication of light-emitting diode devices with high color-rendering abilities and high photostability.</P> <P>Graphic Abstract</P><P>Multi-shell Cd-free nanocrystals were designed such that (1) the outer-most shell was free of reactive sulfide to prevent corrosion (2) the position of the band-edge emission remained unchanged during multi-shell coating. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2jm33962e'> </P>