뜬 바닥구조용 완충재의 동탄성계수 측정에 관한 연구

김하근,김명준,이병권 대한건축학회 2005 대한건축학회논문집 Vol.21 No.1

The aim of this study is to suggest the method of measuring the dynamic stiffness and the loss factor of materials used under floating floors in dwellings by Korea standard (KS F 2868) We measured and compared those of 18 resilient materials in several conditions such as the size of test specimens, the type of excitation methods, pick-up locations and so on in the first result, there's no differences of natural frequency according to vibration pick-up location in the second result, the dynamic stiffness by using sinusoidal signal of exciter is higher than that by using impulse signal of Impact hammer Finally, in case of measuring dynamic stiffness of material which has higher stiffness or is easy to change by bending moment, It should be measured with great care

수목추출물의 생리활성에 관한 연구(Ⅸ) : 아까시나무 심재의 항산화활성 물질 Antioxidative Compounds from Heartwood of Robinia pseudo-acacia

최돈하,이학주,이성숙,김윤근,강하영 한국목재공학회 2002 목재공학 Vol.30 No.4

항산화활성이 우수한 아까시나무 심재 에탄올 조추출물로부터 항산화물질을 탐색할 목적으로 4종의 화합물을 단리하였으며, MS, NMR 등의 분광학적 방법에 의해 그 화학적 구조를 3-β-stigmast-5-en-3-ol(daucosterol)를 비롯하여 스틸베노이드 화합물인 3,3' ,4' ,5-tetrahydroxystilbene과 후라보노이드인 3,3' ,4' ,5' ,7-pentahydroxyflavone(robinetin) 및 3,3' ,4' ,7-tetrahydroxyflavanone(fustin)으로 각각 동정하였다. 단리된 화합물의 프리라디칼 소거능을 측정하여 항산화활성을 검정한 결과, 페놀성 수산기가 5개인 3,3' ,4' ,5' ,7-pentahydroxyflavone은 천연항산화제 및 합성항산화제보다 높은 항산화활성을 나타내어 단리화합물 중 가장 항산화활성이 높은 것으로 나타났다. 또한, 페놀성 수산기가 4개인 3,3' ,4' ,5-tetrahydroxystilbene과 3,3' ,4' ,7-tetrahydroxyflavanone도 천연항산화제인 α-tocopherol보다 높은 항산화활성을 나타내었으나 3-β-stigmast-5-en-3-ol은 항산화활성이 없는 것으로 나타나 프리라디칼 소거능에 의한 항산화활성은 화합물의 페놀성 수산기수에 크게 좌우되는 것으로 판단되었다. 이상의 결과 아까시나무의 높은 항산화활성은 3,3' ,4' ,5' ,7-pentahydroxyflavone. 3,3' ,4' ,5-tetrahydroxystilbene 및 3,3' ,4' ,7-tetrahydroxyflavanone에 기인하는 것으로 사료되었다. Antimicrobial and antioxidative activities on heartwood extractives of domestic species were investigated to develop a natural fungicide or preservative. One steroid, stilbene derivatives and two flavonoids were isolated from heartwood of Robinia pseudo-acacia which has been selected due to its high antioxidative activity among the tested species. The structures were determinded as : 3-β-stigmast-5-en-3-ol(daucosterol), 3,3',4,5-tetrahydroxystilbene, 3,3',4',5',7-pentahydroxyflavone(robinetin) and 3,3',4',7-tetrahydroxyflavanone(fustin) respectively on the basis of spectroscopic data and chemical correlations. According to the results of free radical scavenging activity, 3,3',4',5',7-pentahydroxyflavone was evaluated as the highest antioxidative compound among the four compounds and showed higher radical scavenging activity than those of α-tocopherol and butylated hydroxytoluene(BHT), one of the strongest synthetic antioxidants. 3,3',4',5-Tetrahydroxystilbene and 3,3',4',7-tetrahydroxyflavanone showed higher antioxidative activities than that of α-tocopherol. However, 3-β-stigmast-5-en-3-ol did not show free radical scavenging activity. In this regard, it could inferred that high antioxidative activity of extractives of R. pseudo-acacia was derived from 3,3',4',5',7-pentahydroxyflavone, 3,3',4',5-tetrahydroxystilbene and 3,3',4',7-tetrahydroxyflavanone.

LAN에서 메세지 traffic 유형에 따른 성능 평가

임해진,신근하 三陟大學校 2001 論文集 Vol.34 No.1

Existing campus backbone networks will be replaced by Gigabit ethernet network which is able to handle various types of traffic and satisfying the needs of a large number of applications. For design of the Gigabit Ethernet, it is important to analysis exactly the characteristics of various type of traffic in current campus LAN networks. In this paper, We generalized campus communication networks which use a simulation techniques of QoS evaluation for remote traffic services and compare with the various backbone networks.

방음터널 단면형상에 따른 소음저감 특성 평가 : 터널 내부소음을 중심으로

이원열,김하근,오양기,주문기 대한건축학회 2004 대한건축학회논문집 Vol.20 No.2

It seems inevitable for residential buildings to be high-rise and allocated near traffic roads due to the crowdedness in urban areas. Acoustic environments in those areas have been seriously deteriorated by the increase of traffic vehicles. But sound barriers have a limitation in controlling noise due to diffraction noise from sound barriers. Hence sound barrier is not effective to protect the high-rise apartment from traffic noise. This work aims at evaluating characteristics of noise reduction according to the tunnel section shapes by using 1/5 scale model. We carried out a number of field measurements for 1/5 scale model of noise barrier tunnels with various sectional shapes. The results were as follows 1) The level difference was ranged from 0㏈ to 1.2㏈ according to the opening in the ceiling 2) The level difference was ranged from 0.4㏈ to 2.3㏈ when sound-absorbing materials were increased up to 45% of all surface areas. 3) There was generally good agreement between prediction results and the measurement results.

방음터널 단면형상에 따른 소음저감 예측 및 특성 평가 : 터널 외부소음을 중심으로

오양기,김하근,이원열 대한건축학회 2004 대한건축학회논문집 Vol.20 No.8

Noise emitted from urban arterial roads is getting more serious problem in the environmental quality of living. Though noise barrier is one of measures to mitigate noise levels at housing area, it has a limited effect especially on apartment units high around the roads. Noise barrier tunnel may be another effective device for noise reduction even to high rise apartments. On these basis, this study aims at providing a number of possible sectional shapes of noise barrier tunnels, measuring their effects on noise reduction with 1 to 5 scale model measurements, and proposing/validating a prediction technique of their effects. According to a number of measurements with various sectional shapes or the scaled model, 1)the proposed sectional shapes have affirmative effects on noise reduction, 2)the difference in noise levels between in and out of tunnel are about 10dB whether there is opening in the ceiling or not. 3)results from predictions and the measurements show generally good agreements within 0.3∼3.6 dB(A).

광양지역의 지반전단강도 증가 특성

홍원표,송영석,이근하 중앙대학교 기술과학연구소 2000 기술과학연구소 논문집 Vol.30 No.-

본 연구에서는 연약지반개량공사가 실시된 광양지역을 대상으로 압밀기간동안 개량지반의 물리적, 역학적 변화특성 및 개량효과를 고찰되어 있다. 지반개량전 원지반에서 시료를 채취하고, 모래말뚝 타설직후, 압밀방치중(예상압밀도 50%) 및 압밀완료시(예상압밀도 90%)에도 시료를 채취하여 각각 토질정수를 조사 비교하였다. 그 결과 압밀이 진행되는 동안 지반의 강도는 증가하여, 일축압축강도로 구한 점성토지반의 강도증가율(C_u/P_o)이 0.36이 되었다. 그리고, 일축압축강도로 구한 점성토지반의 강도증가율(C_u/P_o)이 0.36이 되었다. 그리고, 일축압축강도와 함수비는 최대압밀응력에 대하여 유일함수관계를 보이고 있으며, 압밀완료시점(예상압밀도 90%)에서 추정된 비배수전단강도는 측정된 비례수전단강도와 비교적 잘 일치한다. In this study, both physical and mechanical properties of soft grounds are investigated during improvement works of soft grounds in Kwangyang. The properties of soil before ground improvement are compared with the properties of the improved ground after Sand Compaction Pile installation, during consolidation(degree of consolidation 50%), and at the end of consolidation(degree of consolidation 90%). From this result, improvement of the shearing strength of soft grounds can be deserved during consolidation, and the improving rate of shearing strength C_u/P_o is 0.36. The relationship between the shearing strength by unconfined compression tests, consolidation stress and water content shows that both the shearing strength and water content have an unique function relationship. The shearing strength predicted by Rutledge hypothesis shows relatives good agreement with the field strength.

양극성 기분장애에서 세로토닌 수용체 유전자의 다형성(102T/C)에 관하여

지익성,신석철,왕성근,이선우,신용재,김충수,김상국,최하석,오승용,류택근,이영호 대한생물치료정신의학회 1999 생물치료정신의학 Vol.5 No.2

A case of right sided aortic arch with atrial septal defect (초)

Geun Jin Ha,Myeung Joon Sung,Jung Hyeun Kim,Jin Wook Jung,So Yeon Kim,Jin Bae Lee,Jae Kean Ryu,Sub Lee,Ji Young Choi,Oh Chun Kwon,Kee Sik Kim,Sung Gug Chang,Young Soo Lee 대한내과학회 2009 대한내과학회지 Vol.77 No.4S

Cartilage Repair Using Composites of Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells and Hyaluronic Acid Hydrogel in a Minipig Model.

Ha, Chul-Won,Park, Yong-Beom,Chung, Jun-Young,Park, Yong-Geun unknown 2015 Stem cells translational medicine Vol.4 No.9

<P>The cartilage regeneration potential of human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) with a hyaluronic acid (HA) hydrogel composite has shown remarkable results in rat and rabbit models. The purpose of the present study was to confirm the consistent regenerative potential in a pig model using three different cell lines. A full-thickness chondral injury was intentionally created in the trochlear groove of each knee in 6 minipigs. Three weeks later, an osteochondral defect, 5 mm wide by 10 mm deep, was created, followed by an 8-mm-wide and 5-mm-deep reaming. A mixture (1.5 ml) of hUCB-MSCs (0.5??10(7) cells per milliliter) and 4% HA hydrogel composite was then transplanted into the defect on the right knee. Each cell line was used in two minipigs. The osteochondral defect created in the same manner on the left knee was untreated to act as the control. At 12 weeks postoperatively, the pigs were sacrificed, and the degree of subsequent cartilage regeneration was evaluated by gross and histological analysis. The transplanted knee resulted in superior and more complete hyaline cartilage regeneration compared with the control knee. The cellular characteristics (e.g., cellular proliferation and chondrogenic differentiation capacity) of the hUCB-MSCs influenced the degree of cartilage regeneration potential. This evidence of consistent cartilage regeneration using composites of hUCB-MSCs and HA hydrogel in a large animal model could be a stepping stone to a human clinical trial in the future.</P>

Foundation of Management Innovation and a Success Model of Micro Enterprise by Increasing Entrepreneurship and Organization Relationship Analysis

Geun-Ha Suh,Yong-Woong Hong,Soon-Ae Jin,Geum-Je Jo 한국유통과학회 2012 유통과학연구 Vol.10 No.3

After the rapidly changing business management environment and financial crisis, high prices and domestic recession in Korea posed threats to the business survival of small and medium enterprises (SMEs). This paper looks at the potential of micro business owners for sustainable development: those who have a spirit of entrepreneurship and the potential to be a hidden champion. Our study of micro business values uses structure equation modeling by LISREL. We have done so in order to understand the foundation of management innovation and success model of micro enterprise by increasing the entrepreneurship and management performance relationship analysis. A micro-enterprise is a type of small business, found only in Korea, often registered as having ten or fewer employees. We examine the successful type of hidden champions and the influence of entrepreneurship on start-ups in business. As compared to past research on the SME entrepreneurship, this study segments small businesses even further. Small business entrepreneurship was classified into three forms that are most appropriate for the Korean situation today: innovation, risk-taking, and pro-activeness. This research is meaningful as it is Korea’s first empirical analysis on four business types: wholesale and retail sales, food and lodging business, service business, and manufacturing business. Thus far, research on small business entrepreneurship was carried out using small-scale investigative analysis. However, this research attempted to develop a model that can explain a cause-effect relation of the motivational level when it comes to the difference of entrepreneurship by each business type and small business start-up success factors. Various conceptual and operational definitions could be developed in a diverse and precise manner. Independent variables that are related to the success of small businesses can be developed additionally to examine the success factors related to the systematization in detailed m