멜라민 화합물을 이용한 산화 그래핀 도핑 및 특성 평가

김수민,김현,김소양,한종훈,Kim, Sumin,Kim, Hyun,Kim, So Yang,Han, Jong Hun 한국재료학회 2019 한국재료학회지 Vol.29 No.11

In this paper, nitrogen-doped reduced graphene oxide(rGO) is obtained by thermal annealing of nitrogen-containing compounds and graphene oxide (GO) manufactured by modified Hummers' method. We use melamine as a nitrogen-containing compound and treat GO thermally with melamine at over $800{\sim}1,000^{\circ}C$ and 1 ~ 3 hr under Ar atmosphere. The electrical conductivity of doped rGO is measured by 4-point probe method. As a result, nitrogen contents on rGO are found to be in the range of 2.5 to 12.5 at% depending on the doping conditions after thermal annealing. The main doping site on graphene oxide is changed from pyridinic-N and pyrrolinic N to the graphitic site as the heat treatment temperature increases. The electrical conductivity of doped rGO increases as the N doping content increases. As the thermal treatment time increases, the change of both total doping contents and doping sites is slight and the surface resistance is remarkably reduced, which is caused by healing effects of doped graphene oxide at high temperature.

술후 감염조절이 어려웠던 환자의 증례보고

김수민,여환호,김영균,김수관,서재훈,박인순,박인수,김용욱,Kim, Soo-Min,Yeo, Hwan-Ho,Kim, Young-Kyun,Kim, Su-Gwan,Seo, Jae-Hoon,Park, In-Soon,Park, In-Soo,Kim, Young-Uk 대한악안면성형재건외과학회 1997 Maxillofacial Plastic Reconstructive Surgery Vol.19 No.1

Treatment of infected mandibular fracture is confronted with various difficult problem, e.g. nosocomial wound infection, non-union of fracture, osteomyelitis. Recently, nosocomial infection has become a major health problem because of excessive morbidity, personal distress, and cost. Frequently, isolated causative microorganisms of nosocomial infection were staphylococcus aureus, pseudomonas aeruginosa, klebsiella species. The various manifestation of the disease related to the pathogenesis and the clinical course tend to give a bad prognosis after operation. This is a report of case that post-operative infected mandibular fracture in 53-year-old man was not healed even through aggressive I & D and antibiotic treatment.

2단 실린더형 싸이클론의 물 및 오일 액적 제거 성능 분석 연구

김수민,김학준,김명준,한방우,우창규,김용진,Kim, Sumin,Kim, Hak-Joon,Kim, Myungjoon,Han, Bangwoo,Woo, Chang Gyu,Kim, Yong-Jin 한국입자에어로졸학회 2017 Particle and Aerosol Research Vol.13 No.3

A novel two stage cylindrical cyclone was developed for a 3 phase separator in shale oil production industry. The cyclone performance was compared with a cone type cyclone and multi cyclone at the same experimental condition using water and oil mists generated by a humidifier and atomizer at the flow rate 1 to $2m^3/min$. The removal efficiency of total suspended water droplets by the novel cyclone, calculated using inlet and outlet concentrations measured by an optical particle counter, was 99% which is higher than 90% of oil droplet removal efficiency at $2m^3/min$. It might be due to the evaporation of small water droplets during the tests. The water and oil droplet removal performance of the novel cyclone based on the quality factor which is a function of pressure drop and removal efficiency was the highest among three cyclones. The results indicate that the cyclone could be an economical device to remove water and oil mists from shale gas generation processes where a huge three phase separator is commonly used.

광원의 특성에 따른 Boron-doped p-type Cz-Si 태양전지의 광열화 현상 분석

김수민,배수현,김영도,박성은,강윤묵,이해석,김동환,Kim, Soo Min,Bae, Soohyun,Kim, Young Do,Park, Sungeun,Kang, Yoonmook,Lee, Haeseok,Kim, Donghwan 한국재료학회 2014 한국재료학회지 Vol.24 No.6

When sunlight irradiates a boron-doped p-type solar cell, the formation of BsO2i decreases the power-conversion efficiency in a phenomenon named light-induced degradation (LID). In this study, we used boron-doped p-type Cz-Si solar cells to monitor this degradation process in relation to irradiation wavelength, intensity and duration of the light source, and investigated the reliability of the LID effects, as well. When halogen light irradiated a substrate, the LID rate increased more rapidly than for irradiation with xenon light. For different intensities of halogen light (e.g., 1 SUN and 0.1 SUN), a lower-limit value of LID showed a similar trend in each case; however, the rate reached at the intensity of 0.1 SUN was three times slower than that at 1 SUN. Open-circuit voltage increased with increasing duration of irradiation because the defect-formation rate of LID was slow. Therefore, we suppose that sufficient time is needed to increase LID defects. After a recovery process to restore the initial value, the lower-limit open-circuit voltage exhibited during the re-degradation process showed a trend similar to that in the first degradation process. We suggest that the proportion of the LID in boron-doped p-type Cz-Si solar cells has high correlation with the normalized defect concentrations (NDC) of BsO2i. This can be calculated using the extracted minority-carrier diffusion-length with internal quantum efficiency (IQE) analysis.

지역사회 고령자의 낙상경험에 따른 위험요인 비교

김수민,Kim, Soo-Min 대한고유수용성신경근촉진법학회 2016 PNF and Movement Vol.14 No.2

Purpose: This study aimed to investigate the factors that increase fall risk in the residential environment and the perceived fall risk among community-dwelling elderly through comparisons between fallers and non-fallers. Methods: The subjects were 95 community-dwelling elderly aged 65 years and over residing in the metropolitan city of Ulsan. A structured questionnaire consisting of items on sociodemographics and health- and fall-related characteristics was used and data were collected from July to August 2015. The data were analyzed with the SPSS/WIN program. Results: Among recent fallers, 38.9% had diagnosed diseases when the fall occurred, 56.87% were fearful of a recurrent fall, and 86.5% stated that they were increasing their carefulness but that had led to a decrease in activity. There were significant differences between elders who had fallen at least once and elders who had no falls in age, health status, depression, the experience of falling, fear of falling, diseases, and medications. Conclusion: The results indicate a need to assess risk factors to identify older adults with a high risk for falling and the need to develop multifactorial intervention programs that consider both environmental and perceived risk factors as well as physical risk factors to reduce and prevent falls among the elderly.

지역별 옹기의 특성분석 및 발효와의 상관관계 분석 : (1) 지역별 옹기의 물성 및 특성

김수민,노형구,김응수,조우석,Kim, Soomin,No, Hyunggoo,Kim, Ungsoo,Cho, Woo Seok 한국세라믹학회 2015 한국세라믹학회지 Vol.52 No.1

Onggi, described as a 'breathing' type of pottery' has significantly influenced the traditional food culture of Korea. It is known that Onggi is an optimal type of storage for fermented foods such as soy sauce, salted seafood, and Kimchi, as air or liquid can penetrate through the body of this material. These foods gain flavor due to the breeding of aerobic bacteria at the beginning of the fermentation process. In this study, Onggi materials from five regions, Gangjin, Yeoju, Ulsan, Yesan, and Jeju, were collected and analyzed to determine their chemical and physical properties before and after sintering. The differences in the raw materials of other mining regions are examined in terms of their chemical and mineralogical compositions, specific surface area, particle size, and particle distribution. Among them, the Gangjin raw material has the greatest mean particle size of $92.29{\mu}m$, as well as the widest particle size distribution. Differences in the levels of $SiO_2$ and $Fe_2O_3$ are shown among Onggi raw materials. However, the crystalline phases formed after sintering are identical, except for the Jeju samples. At all sintering temperatures tested here, Gangjin Onggi showed the greatest porosity, leading to complete air permeation through the body within 90 minutes. These results taken together indicate that air permeation is strongly related to the pore structures in the Onggi body. This is assumed to affect the fermentation behavior.

분산 안테나 시스템에 기반한 무선 액세스망 가상화

김수민,정방철,Kim, Su Min,Jung, Bang Chul 한국정보통신학회 2012 한국정보통신학회논문지 Vol.16 No.10

본 논문에서는 다수 무선 접속 기술 (Radio Access Technology; RAT)이 통합되어 운용되는 셀룰러 네트워크에서 차세대 이동통신 네트워크 진화 방향인 디지털 유닛 (DU)-라디오 유닛 (RU) 분리 구조를 기본으로 무선 액세스 네트워크 가상화 알고리즘을 제안한다. 제안 무선 액세스 네트워크 가상화 알고리즘은 크게 기본 액세스 네트워크 가상화, RAT 가상화, 액세스 경로 이주 알고리즘으로 구성되고, 순차적인 수행을 통하여 최종 무선 액세스 네트워크 가상화가 이루어진다. 제안 무선 액세스 네트워크 가상화 알고리즘은 3GPP LTE와 WiMAX의 두 무선 접속 기술을 예제로 한 시스템 레벨 시뮬레이션을 통하여 시스템 수율 측면에서 성능이 평가된다. 이 때, 네트워크 트래픽 로드의 비대칭성에 따른 두 가지 시나리오를 고려하고, 제안 무선 액세스 네트워크 가상화 알고리즘은 비대칭적 네트워크 트래픽 로드와 사용자 분포 상황에서도 상당한 성능 이득을 성취한다. In this paper, we propose a wireless access network virtualization algorithm based on a digital unit (DU)-radio unit (RU) separated network structure in a cellular network with multiple radio access technologies (RATs). The proposed wireless access network virtualization algorithm consists of a baseline access network virtualization, RAT virtualization, and access path migration algorithms. Final wireless access network virtualization is performed by sequentially performing these procedures. Through system-level simulations which assume 3GPP LTE and WiMAX systems, the performance of the proposed wireless access network virtualization is evaluated in terms of system throughput for two scenarios according to asymmetry of network traffic load. Numerical results show that our proposed wireless access network virtualization algorithm achieves significant system throughput gain even in asymmetric traffic load and user distribution situations.

편마비 환자의 보행 특성과 기능적 보행지수 변화

김수민,Kim, Soo-Min 대한고유수용성신경근촉진법학회 2006 PNF and Movement Vol.4 No.1

Purpose : Improved walking is a common goal after stroke. Although the neurodevelopmental intervention(PNF) is the most widely used approach in the walking training of hemiparetic subjects. There is little neurophysiological evidence for its presumed effects on gait symmetry and facilitation of paretic muscles during the therapeutic intervention. The study, therefore, investigated the immediate effects of gait entrainment by a PNF techniques. Methods : Included persons with stroke who were living in the community. Sixteen subjects were assigned to the experimental group participated in a measures design that evaluated the subjects with pre-treatment, post-treatment(8 weeks). Temporal-spatial parameter of gait were analysed for using the computerized GAITRite system. Intervention : Training for the experimental group was carried out 3 times a week for 8 weeks. The training sessions were comprised of 50 minutes of walking with pattern and techniques in PNF. Results : The experimental group had improvements in the functional walking ability after 8 weeks treatment and Post-treatment test scores were more significant than the pre-treatment score. The treatment group demonstrated significantly post-treatment test improvement in gait velocity, cadence and FAP. Post-treatment test scores were more significant than the pre-treatment score(p<0.05). Conclusion : The results of this study showed that the PNF exercise intervention can improve functional gait ability. This study provides evidence for the efficacy of PNF treatment at improving locomotor function in chronic stroke.

임플란트와 레진 클래스프를 이용한 심미 가철성 국소의치 증례

김수민,전영찬,정창모,윤미정,허중보,Kim, Su-Min,Jeon, Young-Chan,Jeong, Chang-Mo,Yun, Mi-Jung,Huh, Jung-Bo 대한치과보철학회 2015 대한치과보철학회지 Vol.53 No.1

For the rehabilitation of fully edentulous patients, implant-supported removable partial dentures can be considered as one of the treatment options with complete dentures or implant-supported overdentures. If removable partial dentures are used in combination with a small number of implants placed in strategically important positions, it can offer additional stability, retention and support through implants and reduce a burden of surgical procedures compared with fixed implant-supported prostheses with extensive implant placement. Moreover, the economical benefit can be expected as well. The purpose of this case report is to present a treatment in which an implant-supported removable partial denture was fabricated considering residual alveolar bone status and demands after teeth loss in a patient who had been using a distal extension removable partial denture for a long period of time. In anterior area, fixed prostheses were fabricated with implant placement and in posterior area, short implants provide only support for the removable partial denture. In addition, denture base and clasp were made of thermoplastic acrylic resin. Finally, functionally and aesthetically satisfying treatment results can be achieved. 완전 무치악 환자의 수복 시 총의치나 임플란트 지지 피개의치와 더불어 임플란트를 지대치로 이용하는 국소의치가 치료 방법의 하나로 고려될 수 있다. 적은 수의 임플란트를 전략적으로 중요한 위치에 식립한 후 가철성 국소의치로 수복할 경우, 임플란트를 통해 안정을 얻고 부가적으로 유지 및 지지를 확보할 수 있을 뿐만 아니라 광범위한 임플란트 식립을 통한 고정성 보철물에 비해 환자의 수술 부담을 줄여줄 수 있으며, 치료비용 절감 효과도 기대할 수 있다. 본 증례는 오랫동안 국소의치를 사용해 온 환자에서 치아 상실 후 잔존 치조골의 상태 및 환자의 요구를 고려하여 임플란트 지지 국소의치를 제작한 증례로서 전치부에 식립한 임플란트는 고정성 보철물로 수복하고 구치부의 짧은 임플란트는 지지 기능만 부여하였다. 또한 의치상과 클래스프를 열가소성 아크릴 레진으로 제작함으로써 기능적, 심미적으로 만족스러운 치료 결과를 얻었기에 이를 보고하는 바이다.

전기자극 처리가 한우육의 육색 및 지방산화에 미치는 영향

김수민,김대곤,성삼경 ( S . M . Kim,D . G . Kim,S . K . Sung ) 한국축산학회 1997 한국축산학회지 Vol.39 No.2

The effects of electrical stimulation on lipid peroxidation and meat color were determined in Korean beef stored at 5℃. Electrically stimulated(ES) meat and Non electrically stimulated(NES) meat were homogenized with distilled water. The degree of lipid peroxidation in ES meat was not significantly different from that in NES meat until 10 days of storage(P$gt;0.05), but TBARS(thiobarbituric acid reactive substances) value and Fe^(2+) ion in ES meat were higher than those in NES meat at 15 days of storage, indicating that ES resulted in more free iron(Fe^(2+)) from binding iron. However, there was little difference in the amount of total iron between ES and NES meat during the 5℃ storage(P$lt;0.05). Carnosine contents also tended to be decreased with time, and it showed little degadation of camosine as antioxidant. Heme pigment gradually tended to be increased during the storage at 5℃, but L value(Lightness) of ES meat was higher than that of NES for one day. However, L value tended to be decreased with time after 5 days of storage. The a value(Redness) of ES meat also had the same tendancy as L value of ES meat. Overall, ES meat color was kept more bright red than NES meat color, but they were not significantly different(P$gt;0.05).