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환경 및 시간경과에 따른 건축용 단열재의 열전도율 변화에 관한 실험적 연구
이승언,강재식,정영선,최현중 대한건축학회 2003 대한건축학회논문집 Vol.19 No.12
The objective of this research is to provide the basic experimental data for thermal insulation design standard of buildings and for test criterion. We tested the thermal conductivity of insulation materials which was the insulation materials in domestic buildings with environmental condition change and long-time elapse. In research, we measured change of thermal conductivity with change of contained water rate by weight, test temperature change and the passage of time. the specimens of insulation materials were kept in test condition, which was influenced by the outside environment during long-time elapse test. The result of the research shows 1)the contained water rate of artificial mineral fiber insulations is higher than others, 2)thermal conductivity rises as test temperature goes up, 3)the thermal conductivity of the extruding insulations and hardened Urethane foam changes with environmental condition and time elapse. As a result, the test methods and standards for thermal conductivity properties have much room for consideration.
구내 표준 방사선사진을 이용한 구내방사선촬영기의 선질 평가
이상섭,권혁락,심우현,오승현,이지연,전국진,김기덕,박창서 대한구강악안면방사선학회 2000 Imaging Science in Dentistry Vol.30 No.3
Purpose : This study was to evaluate the beam quality of intraoral X-ray equipments used at Yonsei University Dental Hospital (YUDH) using the half value layer (HVL) and the characteristic curve of intraoral standard X-ray film. Materials and Methods : The study was done using the intraoral X-ray equipments used at each clinical department at YUDH. Aluminum filter was used to determine the HVL. Intraoral standard film was used to get the characteristic curve of each intraoral X-ray equipment. Results : Most of the HVLs of intraoral X-ray equipments were higher than the least recommended thickness, but the REX 601 model used at the operative dentistry department and the X-707 model used at the pediatric dentistry department had HVLs lower than the recommended thickness. The slopes of the characteristic curves of films taken using the PANPAS 601 model and REX 601 model at operative dentistry department, the X-705 model of prosthodontic dentistry department, and the REX601 model at the student clinic were relatively low. Conclusion : HVL and the characteristic curve of X-ray film can be used to evaluate the beam quality of intraoral X-ray equipment. In order to get the best X-ray films with the least radiation exposure to patients and best diagnostic information in clinical dentistry, X-ray equipment should be managed in the planned and organized fashion. (Korean J Oral Maxillofac Radiol 2000; 30: 183-188)
건축 단열재의 장기 경년변화에 따른 열전도율 변화에 관한 실험 연구 Ⅱ
최현중,정영선,김경우,강재식,이승언 대한건축학회 2003 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.23 No.1
The objective of this study is to test for thermal conductivity of architecture insulation materials in domestic buildings with environmental condition change. In study, we measured change of thermal conductivity with test temperature change, long-time leaving and change of contained water rate. For long-time leaving test, the specimens of building insulation materials were kept in test conditions, which were influenced by the outside environment. The results of the study show 1) the contained water rate of artificial mineral fiber insulations was big for others, 2) thermal conductivity rose as test temperature(median) grew up and 3) the extruding insulations and hardened Urethane foam changed thermal conductivity with environmental condition and time elapse.
Treatment of Melasma in Asian Skin Using a Fractional 1,550-nm Laser: An Open Clinical Study
LEE, HYOUN SEUNG,WON, CHONG HYUN,LEE, DONG HUN,AN, JEE SOO,CHANG, HANG WOOK,LEE, JONG HEE,KIM, KYU HAN,CHO, SOYUN,CHUNG, JIN HO Blackwell Publishing Inc 2009 Dermatologic surgery Vol.35 No.10
<P>BACKGROUND</P><P>Melasma is a common hyperpigmentation disorder that can cause refractory cosmetic disfigurement, especially in Asians. Fractional photothermolysis (FP) has been reported to be effective for the treatment of melasma, despite small study populations and short follow-up periods.</P><P>OBJECTIVE</P><P>To evaluate the efficacy and safety of FP for the treatment of melasma in Asians.</P><P>PATIENTS AND METHODS</P><P>Twenty-five patients with melasma received four monthly FP sessions and were followed up to 24 weeks after treatment completion. Efficacy was evaluated using objective and subjective ratings, Melasma Area and Severity Index (MASI), melanin index tracking, and skin elasticity measurements.</P><P>RESULTS</P><P>Investigators observed clinical improvements in 60% and patients in 44% at 4 weeks after treatment, but the figures decreased to 52% and 35%, respectively, at 24 weeks after treatment. Mean MASI scores decreased significantly from 7.6 to 6.2. Mean melanin index decreased significantly after the first two sessions, but it relapsed slightly in subsequent follow-ups. The treatment did not alter skin elasticity. Hyperpigmentation was observed in three of 23 subjects (13%).</P><P>CONCLUSION</P><P>Treatment of melasma with FP led to some clinical improvements, but it was not as efficacious as previously reported at 6-month follow-up. We recommend judicious use of FP for the treatment of melasma in Asian skin because of its limited efficacy.</P>
Lee, Hyoun Wook,Lee, Eun Hee,Ha, Seung Yeon,Lee, Chang Hun,Chang, Hee Kyung,Chang, Sunhee,Kwon, Kun Young,Hwang, Il Seon,Roh, Mee Sook,Seo, Jeong Wook Blackwell Publishing Asia 2012 Pathology international Vol.62 No.9
<P>MicroRNA (miRNA) has a critical effect on tumorigenesis through post‐transcriptional modification and is considered to be potential biomarkers for cancer diagnosis and treatment monitoring. We evaluated the expression pattern of three selected miRNAs (miR‐21, miR‐155, and let‐7a) to evaluate their potential roles by quantitative reverse transcription‐polymerase chain reaction using formalin‐fixed and paraffin‐embedded tissues of 63 surgically resected pulmonary neuroendocrine (NE) tumors (19 typical carcinoids (TCs), 6 atypical carcinoids (ACs), 19 large cell NE carcinomas (LCNECs), and 19 small cell lung carcinomas (SCLCs). Control amplification for U6 small nuclear RNA (U6) was performed in all samples. Normalized Ct values were calculated (Ct<SUB>Experimental miRNA</SUB>‐Ct<SUB>U6</SUB>) for each case and recorded. The expression levels of miR‐21 and miR‐155 were significantly higher in high‐grade NE carcinomas (LCNECs and SCLCs) than in carcinoid tumors (TCs and ACs) (each <I>P</I> < 0.001). The expression level of miR‐21 in carcinoid tumors with lymph node metastasis was significantly higher than in carcinoid tumors without lymph node metastasis (<I>P</I>= 0.010). To the best of our knowledge, the present study is the first to examine the expression patterns of miR‐21 and miR‐155 as an adjunctive diagnostic tool or clinically relevant biomarkers for pulmonary NE tumors.</P>
Minimal heating dose: a novel biological unit to measure infrared irradiation
Lee, Hyoun Seung,Lee, Dong Hun,Cho, Soyun,Chung, Jin Ho Blackwell Publishing Ltd 2006 Photodermatology, photoimmunology & photomedicine Vol.22 No.3
<P>Background and Objective</P><P>Infrared (IR) rays, which comprise approximately 40% of the solar radiation which reaches the earth's surface, have received relatively scant attention. As no standard method has yet been agreed upon for the biological evaluation of IR irradiation, the objective of this study is to suggest a new unit for IR irradiation.</P><P>Methods</P><P>The skin temperature of 38 Korean volunteers was measured after IR irradiation with varying irradiance.</P><P>Results</P><P>Skin temperature after IR irradiation at an irradiance of 2.02 W/cm<SUP>2</SUP> remained unchanged after 652±22 s (mean±standard error), which corresponds, in this case, to a total radiation dose of IR 1317.3±44.84 J/cm<SUP>2</SUP>. This quantity was designated as the minimal heating dose (MHD). We also demonstrated that MHD increased with increasing IR irradiance at lower IR irradiance (1.17 and 2.02 W/cm<SUP>2</SUP>), whereas it became constant at higher irradiance (2.87 and 3.22 W/cm<SUP>2</SUP>). No statistically significant correlations were detected between MHD and volunteers' ages, erythema index, or melanin index.</P><P>Conclusion</P><P>We propose ‘MHD’ as a biological unit for the measurement of IR irradiation.</P>
Pt-Catalyzed Growth of Amorphous SiOx Nanowires
Hyoun Woo Kim,Ik-Mo Lee,Jae-Won Soh,Jong Woo Lee,Keun Hyeung Lee,Mi Kyoung Park,Sang-Eon Park,Seung Hyun Shim,Wan In Lee 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.50 No.I
We have fabricated SiO$_x$ nanowires on a large scale through a Pt-catalyzed process. The scanning electron microscopy (SEM) investigation revealed that the nanowires had diameters in the range of 30 $\sim$ 130 nm. X-ray diffraction (XRD), selected area electron diffraction (SAED), and energy-dispersive X-ray (EDX) analyses indicated that the nanowires were amorphous and consisted only of Si and O elements. The growth of the SiO$_x$ nanowires was most likely controlled by the base-growth mechanism with the assistance of the underlying Pt layer. The room-temperature PL spectrum measurement showed a broad emission band, peaking around 3.0 eV. This simple heating method, with the effectiveness of the Pt catalyst, can be applied to a wide range of substrate materials, which may contribute to producing various useful nanostructures.