임프란트 미세나사선이 주위골 수준변화에 미치는 영향에 대한 1년간의 전향적 비교 연구

신동환,조규성,박광호,문익상,Shin, Dong-Hwan,Cho, Kyoo-Sung,Park, Kwang-Ho,Moon, Ik-Sang 대한치주과학회 2003 Journal of Periodontal & Implant Science Vol.33 No.3

The success of dental implant therapy relies mainly upon the presence and maintenance of bone adjacent to implant. An 1-year prospective study was performed, upon the patients who were diagnosed as having chronic adult periodontitis, and had been treated with dental implant. The purpose of this study was to measure the radiographic bone level changes proximal to Astra Tech Single Tooth Implants (ATST, Astra Tech AB, $M{\"{o}}lndal$, Sweden) with microthread and Astra Tech TiOblast Implant (ATTB) without microthread supporting fixed partial prosthesis. Measurements were used to determine mean marginal bone loss during the first year of loading, 17 subjects with its partial prosthesis supported by 37 implants were followed up for an 1-year period. The marginal bone loss of implants was positively correlated with the retention factor, microthread($Microthread^{TM}$) in crestal area of ATST. The results were as follows. 1. The mean marginal bone loss of ATST was 0.226${\pm}$0.395mm, while ATTB was 0.440${\pm}$0.360mm. There was a statistically significant difference between ATST and ATTB (p<0.05). 2. The mean bone loss of the upper jaw fixtures was 0.269${\pm}$0.265mm for ATST and 0.529${\pm}$0.417mm for ATTB . There was a statistically significant difference between ATST and ATTB (p<0.05). In the lower jaw the corresponding figures were 0.167${\pm}$0.231mm and 0.313${\pm}$0.214mm, respectively. There was no significant difference between ATST and ATTB (p>0.05). 3. The mean bone loss of ATST was lower than that of ATTB at all sites according to bone quality. There was a statistically significant difference between ATST and ATTB at bone quality type III(p <0.05). In conclusion, the mean bone loss of ATST was smaller than that of ATTB . Therefore, the retention factor of crestal area, microthread ($Microthread^{TM}$) was effective to maintenance of marginal bone level around fixture.

랫트뇨중의 Alanine Aminopeptidase와 $\beta$-Glucuronidase 측정에 의한 신장독성 평가에 관하여

신동환,이창우,Shin Dong-Hwan,Lee Chang Wo 한국임상수의학회 1991 한국임상수의학회지 Vol.8 No.1

Present experiment was performed in order to establish the optimal reaction conditions for determination of urinary AAP and GRS activities and to investigate the applicability of urinary AAP and GRS in nephrotoxicity test in rat. The results were as follows ; 1. The optimal pH of phosphate buffer for determination of urinary AAP activity was 7.8. 2. The Michaelis constant of urinary AAP ranged from 0.8 to 1.0mmol/$\ell$ 3. The optimal wave length for determination of urinary GRS activity was 405nm. 4. The optimal pH of acetate buffer for determination of urinary GRS activity was 5.6. 5. The Michaelis constant of urinary GRS ranged from 0.65~0.79mmo1/$\ell$. 6. The AAP activities in gel-filtered samples were significantly higher than those in crude samples. Mean values of AAP activities in gel-filtered samples and crude samples were 29$\pm$20 and 20$\pm$13U/$\ell$, respectively. 7. There was not significant difference between gel-filtered samples and crude samples in urinary GRS activities. Mean values of GRS activities in gel-filtered samples and crude samples were 57$\pm$40 and 56$\pm$39U/$\ell$, respectively. 8. Limits of linearity of urinary AAP and GRS activities were 2.0 and 3.6U/$\ell$, respectively. 9. Within-run imprecisions of the assays, were acceptable, as the coefficients of the AAP activities ranged from 5.5 to 6.3% and those of GRS activities ranged from 1.4 to 6.2%, respectively. 10. Urinary AAP excretion was 675$\pm$227mu/24hrs.kg before administration of potassium dichromate, and increased significantly to 4246$\pm$2567mU/24hrs.kg within 24 hours after administration of potassium dichromate. 11. Urinary GRS excretion did not increase significantly after administration of potassim dichromate. 12. From these findings it is concluded that urinary AAP excretion is early and sensitive Indicator to detect kidney damage in nephrotoxicity experiment.

Design and Fabrication of 26.4 GHz Local Oscillator for Satellite Payload

신동환,류근관,장동필,이문규,염인복,오승엽,Shin Dong-Hwan,Ryu Keun-Kwan,Chang Dong-Pil,Lee Moon-Que,Yom In-Bok,Oh Seung-Hyeub The Korean Institute of Communications and Informa 2006 韓國通信學會論文誌 Vol.31 No.2A

본 논문에서는 위성 탑재체용 26.4 GHz 국부 발진기를 설계 제작하였다. 제작된 발진기는 고안정도와 고신뢰도를 갖는 기본 주파수 발생부와 기본 주파수 발생부로부터 생성된 8.8 GHz의 신호를 3체배하여 26.4 GHz의 최종 발진 주파수를 만들어내는 주파수 체배부로 구성되어 있다. 기본 주파수 발생부는 샘플링 위상비교기(Sampling Phase Detector)를 이용한 위상 고정 방식의 발진기로 구성하였으며 고안정도를 갖는 OCXO를 기준 주파수원으로 사용하였다. 주파수 체배부는 자체 설계한 MMIC 3체배기와 증폭기를 이용하여 크기와 무게를 줄일 수 있었다. 개발된 국부 발진기는 +11 dBm 이상의 출력 전력과 10 kHz와 100 kHz의 오프셋 주파수에서 각각 -96 dBc/Hz와 -105 dBc/Hz의 위상 잡음 특성을 나타내며, 설계 요구규격을 모두 만족한다. A 26.4 GHz phase locked oscillator(PLO) for communication satellite transponder is developed. The PLO consists of fundamental frequency generation module(FFGM) and frequency multiplication part(FMP). The signal of 26.4 GHz is generated through frequency tripling process of 8.8 GHz fundamental frequency. Phase locking technique using sampling phase detector(SPD) is adopted to design the FFGM. The MMIC tripler and amplifier are also designed for the reduction of the size and mass of FMP. The phase noise characteristics are exhibited as -96 dBc/Hz at 10 tHz offset frequency and -105 dBc/Hz at 100 kHz offset frequency, respectively, with the output power over 11 dBm. All performance parameters are complied with the design requirements.

소방관 보조로봇 플랫폼의 내충격성능 향상을 위한 구조 보강 설계

신동환,김윤구,안진웅,Shin, Dong-Hwan,Kim, Yoon-Gu,An, Jinung 대한임베디드공학회 2011 대한임베디드공학회논문지 Vol.6 No.5

In this paper, we describe the structural reinforcement approach of the throwing-type firefighter assistance robot which can be thrown into a fire site to monitor inside the place and search trapped people while ensuring a firefighter's safety. The reinforcement design is focused on high strength with low weight for the robot. The in-depth structural analysis of the platform is carried out to track down the weakest part, especially with the 1.8m height of drop test. The analysis is verified by comparing with the 1.8m height of the drop test of the throwing-type firefighter assistance robot. The optimal approach for improving the strength of the weakest part aims at topological equivalent and equivalently stress distributed shape.

치은박리소파술시 metronidazole gel 병용이 유년성치주염 치료에 미치는 영향

신동환,이동원,문익상,Shin, Dong-Hwan,Lee, Dong-Won,Moon, Ik-Sang 대한치주과학회 2001 Journal of Periodontal & Implant Science Vol.31 No.4

The aim of the study was to investigate the effect of surgical therapy combined with the usage of metronidazole gel in the treatment of juvenile periodontitis by comparing clinical indices of flap operation along with application of metronidazole gel and flap operation only. Comparing clinical indices of the baseline, 3 months after surgery, 6 months after surgery statistically, the results are as follows; 1. Bleeding on probing (BOP) was decreased significantly both in the experimental group and the control group at 3 months after surgery (p<0.05). BOP increased 0.9% in the control group 6 months after surgery, while in the experimental group, decreased 4.7% (p>0.05). However, there was no statistically significant difference in these groups (p>0.05). 2. Pocket probing depth (PPD) was decreased significantly both in the experimental group and the control group at 3 months after surgery (p<0.05). PPD increased 0.lmm in the control group 6 months after surgery, while in the experimental group, no increase of the depth could be observed (p>0.05). However, there was no statistically significant and difference in these groups (p>0.05). 3. Loss of attachment level(LOA) was decreased significantly both in the experimental group and the control group at 3 months after surgery (p<0.05). LOA increased 0.2mm in the control group 6 months after surgery, while in the experimental group, increased 0.3mm However, there was no statistically significant difference in these groups (p>0.05). In conclusion, flap operation was effective on the treatment of juvenile periodontitis. However, combined therapy of metronidazole gel could not give rise to any significant adjunctive effect on the treatment outcome.

청각시스템을 기반으로 한 새로운 오디오 워터마킹 시스템 설계

申東煥(Dong-Hwan Shin),申承源(Seung-Won Shin),金鍾元(Jong-Weon Kim),崔鐘昱(Jong-Uk Choi),金德暎(Duck-Young Kim),金成煥(Sung-Hwan Kim) 대한전기학회 2002 전기학회논문지 D Vol.51 No.7

화염 스프레이 코팅장치 내 유동특성 및 금속 입자의 거동에 대한 수치해석 연구

신동환(Dong Hwan Shin),이재빈(Jae Bin Lee),김남일(Nam Il Kim),조민행(Minhaeng Cho),이성혁(Seong Hyuk Lee) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11

The present study conducted computational simulation for multiphase flow in flame spray coating process with Ni-Cr powders. The numerical model included continuum-type differential equations that described the evolution of gas dynamics, multi-dimensional tracking of particle trajectories and temperature distribution in the turbulent reacting flow field. The flow through a flame spray gun was characterized by complex phenomena involving combustion, turbulent flows, and heat transfer. Nanoparticle movement was calculated by using the discrete phase models(DPM), and we also examined the effect of Ni-Cr metal particle size on flame spray process. From the results, it was found that particle velocity and its temperature were substantially affected by the particle size, thus the particle size should be considered carefully to determine an optimum coating process for metal surfaces.

친수성 표면에서 나노 유체 액적의 증발 특성

신동환(Dong Hwan Shin),이성혁(Seong Hyuk Lee) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.11

The main objective of this study is to investigate the evaporation characteristics and wetting dynamics of nanofluid droplets on hydrophilic surfaces. The evaporation processes of Al₂O₃ nanofluid droplets are visualized for different liquid volumes and particle concentrations, and the in-situ measured total evaporation time, contact radius, and contact angle are presented by using a digital image analysis technique. In addition, the measurements are compared with the theoretical estimation of total evaporation time and the edge shrinking velocities are measured for examining the formation of nanoparticles strains. It is found that the measured initial contact angles decreases as the volume fraction of nanofluid increases, resulting in the decrease in the center-height of droplet, and the total evaporation time decreases with increase in the volume fraction of nanofluid. In particular, the rapid increase in the droplet edge shrinking velocity near a last stage of evaporation can be observed, and it would affect some inward movement of nanoparticles suspended in a base fluid.

기울어진 미세 텍스쳐 표면에 충돌하는 단일 액적의 퍼짐 특성

신동환 ( Dong Hwan Shin ),문주현 ( Joo Hyun Moon ),이성혁 ( Seong Hyuk Lee ) 한국분무공학회 2011 한국액체미립화학회지 Vol.16 No.2

The present study investigated experimentally the spreading characteristics of a single liquid impinging on the inclined micro-textured aluminum (Al 6061) surfaces manufactured by using a micro computerized numerical control (μ-CNC) milling machine. The textured surfaces were composed of patterned micro-holes (diameter of 125 μm and depth of 125 μm). In our experiment, the de-ionized (DI) water droplet of 4.3 μl was impinged normally on the non-textured and textured surfaces at two different Weber numbers, and the droplet impinged on the inclined surfaces with different angles. A high speed camera was used to capture sequential digital images for measurement of the maximum spreading distance. It was found that for the textured surface, the measured apparent equilibrium contact angle (ECA) increased up to 105.8°, higher than the measured ECA of 87.6° for the non-textured (bare) surface. In addition, it is conjectured that the spreading distance decreased because of a liquid penetration during droplet spreading through the holes, the increase in hydrophobicity, and viscous dissipation during impact process.

좁은 간격에서의 비등 열전달 가시화 연구

신동환(Dong Hwan Shin),김영환(Yeonghwan Kim),김진섭(Jin Sub Kim),유승문(Seung Mun You),이정호(Jungho Lee) 대한기계학회 2018 대한기계학회 춘추학술대회 Vol.2018 No.4