이온질화에 있어 피처리물의 온도 특성에 관한 연구

金熙松 단국대학교 1989 論文集 Vol.23 No.-

In ion nitriding, surface hardness and case depth of work piece are re greatly influenced by the treatment temperature. In this thesis, transient temperature characteristics of ion-nitrided workpiece is studied theoretically and experimentally. Assuming uniform distribution of surface heat source, significant modes of heat transfer are considered as conduction and radiation. Analysis of lumped heat capacity for transient temperature rise of workpiece is presented. Effect of radiation shield on transient temperature rise is also investigated. Transient temperature distribution in cylindrical workpiece is numerically analyanalyzed using finiete difference method. Temperature marsurements are made using both themocouples and radiation pyrometer. Experimental data show satisfactory agreement with theoretical results.

構造用 炭素網의 波勞균열 過程에 관한 硏究

金熙松 단국대학교 1980 論文集 Vol.14 No.-

여러 흐름方程式을 非次元媒介變數로 나타내는 것이 大端히 重要하다는 것을 알아왔다. 몇個의 單位를 쓰지만 이러한 接近法은 또한 計算이란 觀點에서 볼 때 便利하고도 簡便한 것으로 알려져 왔다. 더욱이 그것은 다른 方法으로는 밝힐 수 없는 흐름現象의 어떤 性質들을 밝히는데 대단히 有用한 同時에 必要한 相似技法(simulation techniques)을 提供해주는 잇점도 있다. We have examined the cracking occurance and its progress by the torque bending fatigue test with carbon steel, S30C and S33C, which are used for mechanical structure. Prepared for this study were two kinds of test pieces which shows extermely defferent length effect between them. And the fatigue test was accomplished by changing notch radious and its depth. The follwoing results were obtained from the repeated stress effect against sharp notch material of S30C which shows the fatigue cracking and its progress and the effect of notch radious and its depth against the cracking occurance and its progress of the notch test piece S33C. 1. The magnitude of cracking occurance is decided by the parameter of maximum stress ασ_n but the subsequent progress mostly depends on the repeated stress. 2. Under the same stress, the number of repeated stress toward the cracking occurance is smaller as the diameter increases, and the diffrence is larger as the stress is smaller and the notch radious is larger. 3. The diameter ratio of cracking between the small and the large test pieces has changed proportionally against the smallest stress ratio.

Ion 窒化에 있어 添加 炭素量이 殘留應力에 미치는 영향

金熙松 단국대학교 1982 論文集 Vol.16 No.-

This paper deals with residual stress characteristics of ion-nitrided metal which is primarilly concerned with the effects of added Carbon Content in gas atmosphere. A small optimal Amount of Carbon Content in gas atmosphere increase compound layer thickness, as well as to increase diffusion layer thickness and hardness. The residual stress and deflection of the specimens was measured in various elevated temperature at the surface of ion-nitrided metal and the internal stress distribution was calculated. It is found that compressive residual stress at the compound layer is largest at the compound layer, and decreases as the depth from the surface increases.

Shot peening 가공에 의한 노치재의 응력분포와 피로강도의 개선

이승호,김희송 한국공작기계학회 1998 한국생산제조학회지 Vol.7 No.5

Second step shot peening was applied on both smooth specimen and U-notch specimen in order to investigate the stress distribution and the improvement in fatigue strength. Various experiments and measurements such as rotary bending fatigue test and the measurement of compressive residual stress were performed. The results showed that the fatigue strength of second step shot peened specimens increased by 34 percent compared to that of unpeened ones. Compressive residual stress also considerably increased, which resulted in the increase of fatigue strength. Finite element analysis showed that shot peening is effective decreasing the bending stress by external force. The effectiveness of shot peening reducing the compressive residual stress was anticipated by the superposition of the concentrated stress and the compressive residual stress.

차동 기어의 진동 저감을 위한 동력 전달계 진동 해석

최은오,김희송,안병민,홍동표 한국공작기계학회 1997 한국생산제조학회지 Vol.6 No.3

Eigenvalue analysis of vibration mode and an analysis by frequency response among the methods of predicting gear noise are related with transmitting sound of vibration. In this study we intended to reduce the vibration noise of differential gear by reducing torque fluctuation of drive pinion shaft which causes vibration noise of differential gear in rear wheel drive vehicles. For this we developed multi-degree of freedom analysis model in which mass moment of inertia and torsional spring combined and we examined the influence of torsional vibration of driveline elements by performing forced vibration analysis of engine excitation torque. We studied the methods for reducing torsional vibration of driveline according to the design factor of propeller shaft and examined the effect reducing vibration in differential gear by flexible coupling.

自動車 輕量化를 위한 쇼트피닝 加工의 效果

노승남,김희송,이승호 서울産業大學校 1998 논문집 Vol.47 No.1

Exhaust gas of vehicle is a big problem today. Reducing the weight of vehicle is desirable to reduce the cost and to improve the efficiency of vehicle. In the previous work, it seemed that the shot peening of suspension spring of vehicle improved the fatigue strength. Compressive residual stress can be obtained up to -792MPa by shot peening. Fatigue strength of machining spring steel is 425MPa. But fatigue strength of shot peened spring steel increased up to 756MPa.

Skin barrier function recovery after diamond microdermabrasion

KIM, Hei Sung,LIM, Sook Hee,SONG, Ji Youn,KIM, Mi-Yeon,LEE, Ji Ho,PARK, Jong Gap,KIM, Hyung Ok,PARK, Young Min Wiley (Blackwell Publishing) 2009 The Journal of Dermatology Vol.36 No.10

<P>Microdermabrasion is a popular method for facial rejuvenation and is performed worldwide. Despite its extensive usage, there are few publications on skin barrier change after microdermabrasion and none concerning diamond microdermabrasion. Our object was to see changes in transepidermal water loss (TEWL), hydration and erythema of the face following diamond microdermabrasion. Twenty-eight patients were included in this spilt face study. TEWL, stratum corneum hydration and the degree of erythema were measured from the right and left sides of the face (forehead and cheek) at baseline. One side of the face was treated with diamond microdermabrasion and the other side was left untreated. Measurements were taken right after the procedure and repeated at set time intervals. Diamond microdermabrasion was associated with a statistically significant increase in TEWL immediately after the procedure and at 24 h. However, on day 2, levels of TEWL were back to baseline. An increase in hydration and erythema was observed right after microdermabrasion, but both returned to baseline on day 1. The results show that skin barrier function of the forehead and cheek recovers within 2 days of diamond microdermabrasion. Diamond microdermabrasion performed on a weekly basis, as presently done, is expected to allow sufficient time for the damaged skin to recover its barrier function in most parts of the face.</P>

Emerging Need for Vaccination against Hepatitis A Virus in Patients with Chronic Liver Disease in Korea

Song, Hyun Joo,Kim, Tae Hun,Song, Ji Hyun,Oh, Hee Jung,Ryu, Kum Hei,Yeom, Hye Jung,Kim, Seong-Eun,Jung, Hye-Kyung,Shim, Ki-Nam,Jung, Sung-Ae,Yoo, Kwon,Moon, Il-Hwan,Chung, Kyu Won The Korean Academy of Medical Sciences 2007 JOURNAL OF KOREAN MEDICAL SCIENCE Vol.22 No.2

<P>Vaccination against hepatitis A virus (HAV) is recommended for patients with chronic liver disease (CLD), but this has been deemed unnecessary in Korea since the immunity against HAV was almost universal in adults. However, this practice has never been reevaluated with respect to the changing incidence of adult acute hepatitis A. We retrospectively reviewed the medical records of 278 patients with acute hepatitis A diagnosed from January 1995 to November 2005 and prospectively tested 419 consecutive CLD patients from July to December 2005 for the presence of IgG anti-HAV. The number of patients with acute hepatitis A has markedly increased recently, and the proportion of adult patients older than 30 yr has been growing from 15.2% during 1995-1999, to 28.4% during 2000-2005 (<I>p</I>=0.019). Among 419 CLD patients, the seroprevalences of IgG anti-HAV were 23.1% for those between 26 and 30 yr, 64% between 31 and 35 yr, and 85.0% between 36 and 40 yr. These data demonstrate that immunity against HAV is no more universal in adult and substantial proportion of adult CLD patients are now at risk of HAV infection in Korea. Therefore, further study on seeking proper strategy of active immunization against HAV is warranted in these populations.</P>

Sunitinib for Asian Patients with Advanced Renal Cell Carcinoma: A Comparable Efficacy with Different Toxicity Profiles

Kim, Hyo Song,Hong, Min Hee,Kim, Kiyeol,Shin, Sang-Joon,Ahn, Joong-Bae,Jeung, Hei Chul,Chung, Hyun Cheol,Koh, Youngil,Lee, Se-Hoon,Bang, Yung-Jue,Rha, Sun Young S. Karger AG 2011 Oncology Vol.80 No.5

<P>Abstract</P><P><I>Objective:</I> We aimed to describe the efficacy and safety of sunitinib in unselected Korean advanced renal cell carcinoma (RCC) patients. <I>Patients and Methods:</I> From November 2005 to August 2008, 132 histologically confirmed advanced RCC patients (100 in the global expanded access program) were enrolled. Response and toxicity were assessed regularly according to the protocol. <I>Results:</I> Within this population, 82.6% had clear cell RCC, and 28.8% were treatment naïve. Patients received a median of 5 cycles of sunitinib (range 1–30), and the mean relative dose intensity was 82.0 ± 14.20 (SD). The progression-free survival (PFS) and overall survival rates were 8.2 and 23.1 months, respectively. For the 130 evaluable patients, the objective response rate was 34.1% (n = 45); 44.7% (n = 59) exhibited stable disease. Reasons for discontinuation were disease progression (75.0%) and toxicity (7.6%). The most frequent adverse events were thrombocytopenia (75.0%), neutropenia (70.5%), and anemia (69.7%). Low body surface area (OR = 4.2, 95% CI 1.2–13.8, p = 0.02) and previously treated status (OR = 3.1, 95% CI 1.3–7.4, p = 0.01) were highly predictive of grade 3–4 toxicities. Based on these findings, a nomogram predicting the probability of 12-month PFS was constructed, giving a concordance index of 0.675. <I>Conclusions:</I> Despite the different toxicity profiles, maintaining adequate dose modifications and a careful follow-up enables comparable treatment outcomes for unselected Korean advanced RCC patients.</P><P>Copyright © 2011 S. Karger AG, Basel</P>

Complex Nanoparticle of Light-Emitting MEH-PPV with Au: Enhanced Luminescence

Kim, Mi Suk,Park, Dong Hyuk,Cho, Eun Hei,Kim, Kyoung Ho,Park, Q-Han,Song, Hugeun,Kim, Dae-Chul,Kim, Jeongyong,Joo, Jinsoo American Chemical Society 2009 ACS NANO Vol.3 No.6

<P>Complex nanoparticles (NPs) of poly(2-methoxy-5-(2'-ethylhexyloxy)-p-phenylene vinylene) (MEH-PPV) NP adsorbed with Au NPs (MEH-PPV/Au NPs) were fabricated through a reprecipitation method. The formation of MEH-PPV/Au NP complexes was confirmed through high-resolution transmission electron microscopy and Fourier transform infrared experiments. The laser confocal microscope photoluminescence (PL) efficiency of the complex MEH-PPV/Au single NP dramatically increased compared with that of the MEH-PPV single NP without Au NPs, which was directly confirmed through color charge-coupled device images. The enhanced PL efficiency of the MEH-PPV/Au NP complex might have originated from the energy transfer effect in a surface plasmon resonance coupling between a MEH-PPV NP and Au NPs. The strong local field enhancement due to nanogaps between Au NPs in the background of a light-emitting MEH-PPV NP might be another origin of the PL enhancement of the NP complex, as supported by finite difference time domain calculations. We also observed the blue shift of the PL peaks of the single MEH-PPV and MEH-PPV/Au NP, compared with the solution PL peaks of those NPs.</P>