소형펀치 시험과 유한요소 해석을 이용한 SA508 Gr.3 재료물성 예측

전준영(Jun-Young Jeon),김낙현(Nak-Hyun Kim),김윤재(Yun-Jae Kim),이사용(Sa-Yong Lee),김진원(Jin-Weon Kim) 대한기계학회 2013 대한기계학회 춘추학술대회 Vol.2013 No.3

설비공학 분야의 최근 연구 동향

한화택(Hwataik Han),이대영(Dae-Young Lee),김사량(Sa Ryang Kim),김현정(Hyun-Jung Kim),최종민(Jong Min Choi),박준석(Jun-Seok Park),김수민(Sumin Kim) 대한설비공학회 2013 설비공학 논문집 Vol.25 No.6

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2012. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. The conclusions are as follows: (1) The research works on thermal and fluid engineering have been reviewed as groups of fluid machinery, pipes and valves, fuel cells and power plants, ground-coupled heat pumps, and general heat and mass transfer systems. Research issues are mainly focused on new and renewable energy systems, such as fuel cells, ocean thermal energy conversion power plants, and ground-coupled heat pump systems. (2) Research works on the heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer, and industrial heat exchangers. Researches on heat transfer characteristics included the results for natural convection in a square enclosure with two hot circular cylinders, non-uniform grooved tube considering tube expansion, single-tube annular baffle system, broadcasting LED light with ion wind generator, mechanical property and microstructure of SA213 P92 boiler pipe steel, and flat plate using multiple tripping wires. In the area of pool boiling and condensing heat transfer, researches on the design of a micro-channel heat exchanger for a heat pump, numerical simulation of a heat pump evaporator considering the pressure drop in the distributor and capillary tubes, critical heat flux on a thermoexcel-E enhanced surface, and the performance of a fin-and-tube condenser with non-uniform air distribution and different tube types were actively carried out. In the area of industrial heat exchangers, researches on a plate heat exchanger type dehumidifier, fin-tube heat exchanger, an electric circuit transient analogy model in a vertical closed loop ground heat exchanger, heat transfer characteristics of a double skin window for plant factory, a regenerative heat exchanger depending on its porous structure, and various types of plate heat exchangers were performed. (3) In the field of refrigeration, various studies were executed to improve refrigeration system performance, and to evaluate the applicability of alternative refrigerants and new components. Various topics were presented in the area of refrigeration cycle. Research issues mainly focused on the enhancement of the system performance. In the alternative refrigerant area, studies on CO2, R32/R152a mixture, and R1234yf were performed. Studies on the design and performance analysis of various compressors and evaporator were executed. (4) In building mechanical system research fields, twenty-nine studies were conducted to achieve effective design of mechanical systems, and also to maximize the energy efficiency of buildings. The topics of the studies included heating and cooling, HVAC system, ventilation, renewable energy systems, and lighting systems in buildings. New designs and performance tests using numerical methods and experiments provide useful information and key data, which can improve the energy efficiency of buildings. (5) In the fields of the architectural environment, studies for various purposes, such as indoor environment, building energy, and renewable energy were performed. In particular, building energy-related researches and renewable energy systems have been mainly studied, reflecting interests in global climate change, and efforts to reduce building energy consumption by government and architectural specialists. In addition, many researches have been conducted regarding indoor environments.

서울 남산 화강암의 풍화에 관한 환경광물학적 연구

김원사,이대준,신현숙 忠南大學校 環境問題硏究所 1998 環境硏究 Vol.16 No.-

The weathering of Namsan granite of Seoul was studied by polarizing microscopy, X-ray fluoresence spectroscopy and X-ray diffraction. The rock consists principally of quartz, feldspars and micas, together with very small amount of garnet, sillimanite, chlorite, sericite, muscovite, cordierite, zircon, and opaque minerals. Under the polarizing microscope, the weathering of the rock begins to breakdown of the feldspars into sericite and is then followed by alteration of quartz into micas. Decrease of amount of feldspars and quartz and increase of micas, with progress of weathering, are also confirmed by X-ray diffractogram. With advancing weathering, K₂O and Al₂O₃ markedly increased, while Na₂O, CaO, Fe₂O₃, TiO₂, and MnO₂ decreased. When water having penetrated into the rock through cracks and pore space developed between the minerals it becomes to react with minerals in contact resulting in strong alkaline or weak acidic solution. This kind of solution is interpreted to be a principal factor for the wathering of the rock.

서울 남산의 절리 발달에 관한 연구

김원사,신현숙,이상언 忠南大學校 環境問題硏究所 1997 環境硏究 Vol.15 No.-

Distribution and nature of geological fractures including joints and faults was investigated for the Mt. Namsan of Seoul. The mountain consists of banded gneiss of Precambrian age and biotite granite of Jurassic era. The gneiss is marked by well developed gneissosity of NNW-strike and NE-dip. The granite is medium to coarse- grained in texture and is composed principally of quartz, plagioclase, K-feldspar, and bioite. A big fault has been discovered at the 200 m northwest side of the main peak (262 m). It strikes N30。 E and dips 80。SE, and extends about 300 m. Pole-density diagram was established on the basis of orientation data of 73 joints measured. Nature of joints such as spacing, extension, termination type, and occurrence frequency was analysed and tabulated. It is expected that numerous fractures within the Mt. Namsan granite, together with textural and mineralogical features of the biotite granite, have attributed to the weathering processes of the rocks.

통계적 에너지 해석법에 의한 선박소음 예측프로그램 개발에 관한 연구

김사수,현명환,김명현,이도경 부산대학교 1994 生産技術硏究所論文集 Vol.47 No.

선박에 있어서 소음은 공기중 소음(Airborne Noise), 구조전달 소음(Structureborne Noise), 수중방사 소음(Waterborne Noise)으로 나눌 수 있다. 선박소음을 예측하는 과정에서 고체소음전달해석은 직접적으로 예측결과의 정도에 영향을 미치므로 이에 대한 적절한 해석 기법의 개발이 요구된다. 본 연구에서는 고체음 전달해석을 수행하기 위하여 통계적 에너지 해석법(Statistical Energy Analysis-SEA)의 방법에 의해 고체소음 전달 손실을 이론적으로 예측하고 실험모델을 이용하여 각종 파라메터 추정 및 그에서 얻은 실험치와 비교분석을 함으로서 그 타당성을 확인하고 이의 결과를 보다 복잡한 선박구조물에 적용하여 고체소음 수준을 예측하는 방법으로서의 가능성을 확인하고자 한다. In order to build a quiet and comfortable ship, the noise levels on board ship must be predicted at early design stage. Statistical Energy Analysis(SEA) developed by R.H.Lyon has been well known to be the most useful frame work to study the energy flow of noise and vibration in structure. This paper applied this theory to predict the transmission loss of structureborne noise of model structure and have developed computer program. Components constructing model structure have been all considered as SEA elements. To examine the accuracy of the program, experiments were carried out on model structure with a white noise as a noise source. And we also estimated the SEA parameters from the model structure. The results of comparison between the calculated and measured data have shown good agreement.

와편의 연대결정에서 SAAD방법과 SAR방법으로 측정한 연대측정 결과 비교

김현식,홍사용,서만철 공주대학교 문화재보존과학연구소 2003 문화재과학기술 Vol.2 No.1

경기도 하남시 천왕사지에서 채취한 와편으로부터 석영을 분리하여 SAAD방법과 SAR방법을 적용 연대를 측정하였다. SAAD 방법에 의한 자연축적선량 값은 5.37±0.32Gy, SAR 방법에 의한 값은 5.40±0.22Gy이었다. 이것은 오차범위 내에서 일치하는 값이다. 연간선량은 4.31±0.17Gy/ka로, 측정연대는 SAAD방법의 경우 AD 756±53년, SAR방법의 경우 AD 750±45년이다. The roof tiles excavated from Cheonwangsaji at Hanam-shi in Gyeonggi province were dated by using SAAD and SAR protocols. The paleodoses by SAAD and SRR protocols were 5.37±0.32 Gy and 5.40±0.22 Gy, which were agreed with in the range of the measurement error. The evaluated dose rate from the soil around the excavated roof tiles and the tile themselves was 4.31±0.17Gy/ka and the ages of the roof tiles were determined to be (756±53)AD by SAAD and (750±45)AD by SAR.

船體의 springing 振動에 관한 硏究

김사수,윤경화,강현주 부산대학교 1994 生産技術硏究所論文集 Vol.47 No.

비교적 완만한 해상에서 선수 벌브를 가진 배가 밸러스트 상태로 항해할 때 수직이절진동으로써 상당한 진동이 발생한다는 사실은 잘 알려지고 있다.[17] 파중에서 슬래밍이나 청파에 의한 whipping진동에 대해서는 이미 많은 연구[16]∼[18]가 행해져 왔지만 완만한 해상에서 springing진동에 관한 연구는 비교적 적은 편이다. 본 논문의 목적은 주로 항해중인 선박에서 중요한 문제가 되는 소위 springing현상에 대해서 이론적 및 실험적으로 고찰할려는 것이다. 본 논문에서는 선체진동의 원인을 주기적인 파에 의한 외력이라 가정하고, 또 운동방정식을 풀기 위해서 선체를 Euler & Bernoulli 보로 그리고 서측은 수직으로 간주했다. 또 외력은 주기파에 기인한 부력변화로 보아 1차 mode 및 2차mode의 상호 비교와 1, 2, 3차 공진시의 각각의 기여도를 조사해보았다. 이때 이 이론해석은 몇몇 동적요소 및 비선형성을 고려하면 광석운반선이나 원유수송선 등에 실제 응용될 수 있다고 생각된다. There is well known fact that the considerable vibration occured by two node vertical ship hull vibration even if the ship sails on the calm water under the ballast conditions. There have been quite a many researches about Whipping Vibration caused by slamming, green water on the wave, but the research about Springing vibration has not frequently researched. So this paper aimed at springing phenomena which came up to main issue as the ship sails .Also, this paper explains the cause of ship vibration as a periodic external force, the ship as a Euler & Bernoulli beam, and ship side as a transverse bulkhead additionally, we take the external force as the buoyance spectrum caused by periodic wave. Firstly, we compared 1st mode and 2nd mode, then we check out the effectiveness fo each 1st, 2nd, 3rd mode under the resonance condition. I think that this analysis of the theory can be applied to any bulk carrier and VLCC, if the dynamic element and nonlinearity are considerable.

텍타이트와 흑요석의 특징 및 성인 비교 : Their Characteristics and Origin

김원사,신현숙 충남대학교 기초과학연구소 2003 忠南科學硏究誌 Vol.30 No.1

During the past fifty years, the origin of natural glassy objects, called tektite, has long been a topic in the science community. In this study mineralogical and chemical data for tektites, collected from China, have been investigated. Obsidian, a very similar resemblance, has also been studied, in the hope to characterize it better and also to compare it with tektites. It is confirmed, on the basis of presently obtained data, that the Chinese teckites are believed to originate from terrestrial rocks melted by hypervelocity impacts of large and extraterrestrial objects. In contrast, obsidian is a volcanic glass of rhyolitic composition and is originated from magma during volcanic eruption.

5년간 시행된 인공치아매식술에 관한 일차보고

김수민,조사현,조세인,계기성,여환호,김영균,정재현 大韓顎顔面成形再建外科學會 1996 Maxillofacial Plastic Reconstructive Surgery Vol.18 No.1

We experienced 152 endosseous implant surgery and prosthodontic restoration with edentulous jaw for 5 years from Mar. 1990. to Oct. 1995. 422 fixtures were implanted. the ratio of male to female was 1.38 : 1 and the range of age from 16 to 74 years. Most dominant group was 41 to 50 years group(36%). In our study, implant success rates showed 96% in mandible and 92% in maxilla. The major causes of implant failure of primery osseointegration(75%), overloading(15%), neurologic problem(5%), psychologic problem(5%).

1980년대 민중문학론 연구

장사선,김현주 弘益大學校 人文科學硏究所 2002 人文科學 Vol.10 No.-

With respect to the Korean history of literature, a literature survey, which has been represented by the terms such as the multitude and the general public, has changed its appearance in concert with historical characters on a consistent basis. In particular, in the 1980s literary men succeeded in putting their existing theories into practice because political and social situations were so complicated in the 1980s. If the relationship between the reality and literature is tight, chances are very high that literature could reflect on the political and social circumstances. As a result, it was possible that the public, not a small number of people, can be engaged in real life because people’s perception of actuality is abundantly clear at that time. Taking 1980s’ popular literature into consideration, there were several meanings and limits. First of all, in terms of 1980s’ literature the public played active roles. Secondly, their movement expanded the realm of literary genre because they were the main body of the activities. Thirdly, debates on democratic literature by literary men escalated into actions with political and social turmoils in those days. Lastly, people from all levels of society including students jumped on the bandwagon of popular literature with shared target. However, their limits were evident as follows: First and foremost, even though the masses were the main character, the debates had been ceased by outside pressures. The second reason is that they ignored the essentials of popular literature by putting the public’s participation in the literature ahead of it. They should have focused on both sides. The third ground is that they made fatal mistakes in which they just centered around radical measures. Because of this, the public could not join in. The fourth reason, extremist in the literary community clumsily borrowed the literary concepts that are outdated even in North Korea. It is very troubling that their attitude leaved a lot of problems in the literary circles with their ignorance of lyricism, artistic sensitivity and idiosyncracy. So far what we can realize in dealing with the popular literature is that discussion on the literature depends on the variations of political and social situations. It seems hard to determine that what is going on for the future in the literary world. Nonetheless, it is expected that debates on the literature will be much more progressive.