철근콘크리트 원형기둥의 나선철근 최소철근비에 대한 평가

김영식,김형국,박천범,김상우,김길희,Kim, Young-Seek,Kim, Hyeong-Gook,Park, Cheon-Beom,Kim, Sang-Woo,Kim, Kil-Hee 한국구조물진단유지관리공학회 2017 한국구조물진단유지관리공학회 논문집 Vol.21 No.6

원형 기둥의 나선철근은 축방향 철근의 위치 고정 및 좌굴방지와 코어콘크리트의 충분한 횡구속으로 기둥의 연성거동에 효과적인 역할을 한다. 각국은 기둥에 요구되는 연성을 확보하기 위하여 나선철근의 최소철근비를 제시하고 있다. ACI 318-14와 국내 콘크리트 구조설계 기준에서 제시하는 나선철근 최소철근비는 Richart et al.(1928)의 이론에 기초하여 개발되었으며 현재까지 사용되고 있다. 그러나 Richart et al.(1928)의 이론은 현대의 고강도 콘크리트, 고강도철근 그리고 나선철근의 배근조건 등의 영향을 고려하지 못한다. 이 연구에서는 나선철근으로 구속된 철근콘크리트 원형 기둥의 내력회복 및 연성증진에 요구되는 나선철근에 대한 수정 최소철근비 산정식을 제시한다. 수정 최소철근비 산정식은 콘크리트 압축강도, 나선철근 항복강도, 기둥의 단면적, 나선철근 배근간격, 나선철근 직경의 영향을 고려하고 있다. 이 논문에서는 재료강도 및 나선철근 최적비를 변수로 한 실험체의 일축 압축실험을 통하여 ACI 318-14에 제시하는 나선철근 최소철근비 산정식의 타당성을 검토하고, 그 결과를 토대로 나선철근 최소철근비 산정식의 수정방안을 고찰하였다. Spiral reinforcement in a circular column plays an effective role in the ductile behavior of a column through position fixing and buckling restraining of the longitudinal reinforcement, and confining core-concrete. Each country has suggested the minimum volumetric ratio of spiral reinforcement in order to secure the ductility of concrete columns. The minimum volumetric ratio of spiral reinforcement suggested by ACI 318-14 and the national concrete structure design standard was developed based on the theory of Richard et al. (1928); furthermore it has been used until now. However, their theory cannot consider the effects of high strength concrete and high strength reinforcement, and arrangement condition of the spiral reinforcement. In this study, a modified minimum volumetric ratio equation is suggested, which is required to improve the ductility of reinforced concrete circular columns and to recover their stress. The modified minimum volumetric ratio equation suggested here considers the effect of the compressive strength of concrete, the yield strength of spiral reinforcement, the cross sectional area of columns, the pitch of spiral reinforcements and the diameter of spiral reinforcement. In this paper, the validity of the minimum volumetric ratios from ACI 318-14 and this study was investigated and compared based on the results of uniaxial compression experiment for specimens in which the material strength and the spiral reinforcements ratio were used as variables. In the end of the study, the modification method for the suggested equation was examined.

고탄소강의 연속 건식 신선 공정에서 선재의 온도 예측 기법 개발

김영식,김동환,김병민,김민안,박용민,Kim, Yeong-Sik,Kim, Dong-Hwan,Kim, Byeong-Min,Kim, Min-An,Park, Yong-Min 대한기계학회 2001 大韓機械學會論文集A Vol.25 No.2

Wire drawing process of the high carbon steel with a high speed is usually conducted at room temperature using a number of passes or reductions through consequently located dies. In multi-stage drawing process, temperature rise in each pass affects the mechanical properties of final product such as bend, twist and tensile strength. Also, this temperature rise during the deformation is the reason that the wire in drawing process is broken by the embrittlement due to rapid strain aging effect. This paper presents the estimation of the wire temperature for the multi-stage wire drawing process. Using the proposed calculation method of wire temperature, temperature rise at deformation zone as well as temperature drop in block considering the heat transfer between the block and wire were calculated. As these calculated wire temperatures were applied to the real industrial fields, it was known that the calculated results were in a good agreement with the measured wire temperature.

티타니아 세라믹 熔射皮膜의 機械的 特性에 미치는 熔射條件의 影響에 관한 硏究

김영식,김영식,Kim, Yeong-Sik,Kim, Yeong-Sik 한국마린엔지니어링학회 1991 한국마린엔지니어링학회지 Vol.15 No.3

The purpose of this investigation is to examine the effects of spraying conditions on the mechanical properties of flame-sprayed titania ceramic coating layer. Titania ceramic was sprayed onto the mild steel substrate under the various spraying conditions. Spraying distances were 100, 150, 200, 250mm respectively and pinch air pressures were 0.2 0.3, 0.4 MPa at each spraying distance. The mechanical properties such as microhardness, adhesive strength and erosion wear resistance were tested for the specimens sprayed under the various spraying conditions above mentioned. The optimum operational conditions obtained through the experimental results were 150mm of spraying distance and 0.3 MPa of pinch air pressure.

레토르트 및 감마선 조사에 의한 화닭 덮밥 소스의 미생물 제어 효과 비교

김영식,김현주,윤요한,신명곤,김천제,신미혜,이주운,Kim, Young-Sik,Kim, Hyun-Joo,Yoon, Yo-Han,Shin, Myung-Gon,Kim, Cheon-Jei,Shin, Mee-Hye,Lee, Ju-Woon 한국축산식품학회 2010 한국축산식품학회지 Vol.30 No.1

This study evaluated the antimicrobial effects of retort process and gamma irradiation on reduction of total bacterial populations in spicy chicken sauce, which is served on top of the steamed rice. Commercial spicy chicken sauce was treated with retort and gamma ray at 0, 1, 3, 5, and 10 kGy. Total aerobic bacterial populations were then enumerated on plate count agar and isolated bacteria from the test samples were identified using PCR analysis. Moreover, gamma ray sensitivity of identified bacteria was evaluated by $D_{10}$ values, and genotoxicity of gamma-irradiated samples was examined. Gamma irradiation at 3 kGy reduced total aerobic bacterial cell counts in spicy chicken sauce below detection limit, but total aerobic bacterial cell counts in test samples treated with retort were 2.1 log CFU/g. Identified bacteria from the samples were Bacillus subtilis, B. amyloiquefaciense, and B. pumils, and the $D_{10}$ values for B. subtilis and B. cereus were 0.39 ($R^2\;=\;0.921$) and 0.28 log CFU/g ($R^2\;=\;0.904$), respectively. The SOS chromotest showed that the gamma-irradiated spicy chicken sauce did not cause mutagenicity. These results indicate that gamma irradiation of spicy chicken sauce could be useful in ensuring microbial safety.

가정의학과 외래 우울증환자에서 moclobemide의 안전성 및 유효성 평가를 위한 시판후조사

김영식,이근미,김병성,신호철,성은주,이상엽,문유선,송상욱,김철환,선우성,Kim, Young-Sik,Lee, Keun-Mi,Kim, Byung-Sung,Shin, Ho-Cheol,Sung, Eun-Ju,Lee, Sang-Yeoup,Moon, Yoo-Sun,Song, Sang-Wook,Kim, Cheol-Hwan,Sunwoo, Sung 대한임상약리학회 2002 臨床藥理學會誌 Vol.10 No.1

Background : Depression is quite a common disease in primary care however, studies for the safety and effectiveness of antidepressants in primary care setting are rare in Korea. Objectives : This multi-centered post-marketing study was performed to evaluate the safety and effectiveness of Moclobemide and to find out the factors related to the adherence among patients with depression in family practice. Methods : A total of 386 patients were enrolled from July 1999 to January 2000 by twenty family doctors from fifteen family practice centers. They were prescribed Moclobemide and were reevaluated at the 4th, 8th, and l2th week. Evaluation of compliance, safety and effectiveness were performed with pre-made, structured self-reported questionnaires. Evaluation of effectiveness was also performed utilizing self-rating depression scale (SDS). Results : Among 386 patients, safety was evaluated in 310 patients and effectiveness was evaluated in 239 patients. During the first 12 weeks, the number of subjects continuing with Mocclobemide was 136(37.1%). 141 subjects (38.4%) discontinued taking the drug and 90 subjects (24.5%) dropped out at the 12th week. Considering drop-out patients as ineffective cases, overall effectiveness was estimated to be 84.5%. Symptoms improved with time in patients whose follow-up were completed (P<0.01). The SDS score decreased by an average of ${6.8{\pm}9.1(12.2{\pm}19.1%)}$ after 12 weeks(p<0.01). During the study, 33(10.6%) subjects reported adverse events. The most commonly reported adverse events, in descending order, were dizziness(2.3%), headache(1.6%), insomnia(1.3%), facial edema(1.3%), constipation(1.0%), nausea(1.0%) and tremor(1.0%). The main reasons for discontinuing antidepressants were attributed to improvement of symptoms and manifestation of adverse events. Conclusion : The percentage of adherence at 12th week of Moclobemire among patients suffering from depression in the family practice outpatient clinic was shown to be 49%. The antidepressant effect and safety of Moclobemide was relatively superior.

의료용 레이저

김영식,Kim, Yeong-Sik 한국광학회 2010 광학과 기술 Vol.14 No.2

강과 함께 하는 지역축제 1 - 산천어축제가 이뤄낸 지역의 변화

김영식,Kim, Yeong-Sik 한국하천협회 2013 하천과 문화 Vol.9 No.1

전도성 금속 피복재의 전기전도도에 의한 전자파 차폐효과 분석

김영식,최익권,김성수,Kim, Yeong-Sik,Choe, Ik-Gwon,Kim, Seong-Su 한국재료학회 1999 한국재료학회지 Vol.9 No.9

전자파 차폐특성 측정방법의 일환으로 매질의 전기전도도로부터 차폐효과를 정성적 수준에서 예측하는 연구를 수행하였다. 사용된 시편은 전도성 금속 (Cu, Ni)이 피복된 망사형 차폐재로 두께는 0.1 mm 정도이고, 전기전도도는 6.4$\times$10~2.4$\times$10(sup)5 mhos/m 범위 값을 가졌다. 물질상수와 시편의 두께로 표시되는 반사손실 및 흡수손실의 이론식을 도출하고 상기 시편에 대해 차폐효과를 계산하였다. 전도성 피복재의 경우 주된 차폐기구는 반사손실임을 밝힐 수 있었으며, 전기전도도가 증가함에 따라 차폐효과는 현저히 증가함을 알 수 있었다. 이들 이론치를 임피던스 실측치로부터 계산된 반사손실과 비교한 결과 10 dB 이내의 오차를 보임으로써 제안한 분석방법의 타당성을 입증하였다. As an alternative evaluation method of electromagnetic shielding properties, the material parameters are considered in determining the qualitative value of shielding effectiveness. The specimens are metallized nylon fabrics with the thickness of about 0.1 mm and the electrical conductivities in the range from 6.4$\times$10~2.4$\times$10(sup)5 mhos/m. On the basis of shielding theory, the shielding effectiveness (which is a sum of reflection loss and absorption loss) has been determined from the material parameters of the barrier sheets. For the conductive fabrics, the dominant shield mechanism is predicted to be reflection loss, which shows an increasing function of electrical conductivity. Comparing these theoretical value with the directly measured surface impedances, the error range is found to be within 10 dB, which demonstrates that the proposed material-parameters method can be a convenient way to determine the electromagnetic shielding properties.

Fe - Cr - Mn - W 계 스테인리스강의 미세 조직 특성 및 부식 저항성에 미치는 질소 첨가와 소둔 열처리의 영향 ( 1 )

김영식,박용수,홍준화 ( Young Sik Kim,Yong Soo Park,Jun Hwa Hong ) 한국부식방식학회 1996 Corrosion Science and Technology Vol.25 No.1

유연한 LCZ와 집합 크기를 갖는 새로운 이진 LCZ 수열 집합의 생성

김영식,장지웅,노종선,정하봉,Kim, Young-Sik,Jang, Ji-Woong,No, Jong-Seon,Chung, Ha-Bong 한국통신학회 2007 韓國通信學會論文誌 Vol.32 No.3C

이 논문에서는 파라미터 $(2^{n+1}-2,M,L,2)$를 갖는 새로운 낮은 상관 구역 수열을 생성한다. 이 방식에서는 자유롭게 낮은 상관 구간의 길이 L을 선택할 수 있으며, 이에 따라서 집합의 크기 M이 결정이 된다. 그리고 이 생성방식을 사용하게 되면 선택된 낮은 상관 구간의 길이 L과 집합의 크기 M이 Tang, Fan, 그리고 Matsufuji 한계를 기준으로 최적에 가까운 집합을 생성할 수가 있다. In this paper, we construct new LCZ sequence sets with parameters $(2^{n+1}-2,M,L,2)$. In this scheme, we can relatively freely choose the LCZ length L and the resulting LCZ sequence set has the size in which is nearly optimal with respect to Tang, Fan, and Matsufuji bound.