아스팔트 콘크리트의 고온변형저항 특성 측정방법 개발

김광우,이문섭,김중렬,이순제 강원대학교 부설 석재복합신소재 제품연구센터 2002 석재연 논문집 Vol.7 No.-

본 연구는 정하중하에서 아스팔트 혼합물의 소성변형 저항특성을 측정할 수 있는 새로운 시험방법을 개발하기 위하여 수행되었다. 2가지 골재(편마암, 화강암)와 6가지 아스팔트(일반아스팔트, 5가지 개질 아스팔트)를 사용하여 총 12개의 밀입도 혼합물을 제작하였다. 마샬 배합설계를 통해 최적아스팔트 함량을 구하고, 결정된 최적아스팔트 함량으로 마샬공시체(S=10 cm)와 자이레토리 공시체(S=15cm)를 제작하여 마샬안정도시험, 휠 트랙킹 시험, 개발된 김테스트(Kim -test)를 수행하였다. 김테스트는 공시체와 하중봉을 지지할 수 있는 김시험장치(Kim tester)를 이용하여 하단이 반경(r) 0.5 또는 1.0cm로 원형절삭한 직경(D) 3cm, 4cm의 하중봉을 사용한다. 또한 재하는 마샬 하중재하 장치를 사용하여 공시체를 60℃ 수조에 30분동안 수침시킨 후 실시되었다. 정하중은 공시체의 직경방향이 아닌 축 방향으로 50 mm/min가 가해졌고, 최대하중(P_max)과 수직변형(y)이 측정되었다. 마샬안정도시험과 간접인장강도시험에서 얻어지는 것과 유사한 곡선이 각각의 시험에서 얻어졌다. 강도값은 P_max, r, y 및 H(=D-2r)을 이용한 K_D=4P_max/π(H+2√(2ry-y^2))^2식을 통하여 계산하였고, 이를 변형강도(kgf/㎠)로 정의하였다. 실험결과, 공시체 직경이나 골재종류보다는 하중봉과 하중봉 하단의 원형처리 여부가 K_D와 P_max 값에 영향을 미치는 것으로 나타났다. 통계분석결과에서 K_D가 소성변형 깊이와 동적 안정도에 높은 상관성을 보였다. 향후 연구를 통해 K_D의 유효성이 검증된다면, Kim-test는 아스팔트 혼합물의 소성변형 저항성을 판단할 수 있는 시험방법으로 사용될 수 있을 것이다. This study dealt with developing a new approach for finding properties which might represent rut resistance characteristics of asphalt mixture under static loading. Two aggregates, a normal asphalt (pen 60-70) and 5 PMAs were used in preparation of 12 dense-grade mixtures. Marshall mix design was used in determination of the optimum asphalt content (OAC) and each mixture at the OAC was prepared for a newly-developed Kim test on Marshall specimen (S=10 cm) and gyratory specimen (S=15cm), and for wheel tracking test. Kim test used Marshall loading frame and the specimen was conditioned for 30min at 60℃ before loading through Kim tester, and apparatus consisting of a loading column and a specimen and column holder. Diameter (D) of column was 3cm and 4cm with each column having different radius (r) of round cut at the bottom. The static load was applied at 50mm/min in axial direction of the specimen, not in diameteral direction, and the maximum load (P_max) and vertical deformation (y) at the maximum load point were measured. A curve, similar to the one from a Marshall test or static indirect tensile strength test was obtained from each test. A strength value was calculated based on the P_max, H(=D-2r). r and y by using the equation K_D=4P_max/π(H+2√(2ry-y^2))^2 and is defined as deformation strength (kgf/㎠). The values of P_max/y and K_I=K-D/y were also calculated to see if these have any correlation with rutting. In general, D and r were significant factors affecting K_D, while specimen size was not. The statistical analyses results showed the K_D had the best correlation with rut depth and dynamic stability. The next best correlation was found from P_max which was followed by P_max/y and K_I in order. Therefore, K_D can be used for selecting the highly resistable asphalt mixture against permanent deformation.

Mechanical meibomian gland squeezing combined with eyelid scrubs and warm compresses for the treatment of meibomian gland dysfunction : Meibomian gland squeezing for MGD<i>Lee, Kim, Park, Kim, Seo and Kim</i>

Lee, Hun,Kim, Minseo,Park, Si Yoon,Kim, Eung Kweon,Seo, Kyoung Yul,Kim, Tae-im Wiley Blackwell (Blackwell Publishing) 2017 Clinical & experimental optometry Vol.100 No.6

한라산 주변에 발생하는 Karman Vortex Street 재현

권지혁(Kwon Ji-hyuk·Lee),이연원(Lee Yeon-won),김영덕(Kim Young-duk),박광열(Park Kwang-yul) 한국풍공학회 2006 한국풍공학회지 Vol.10 No.1

늦가을과 초본 사이 제주도 후면에 Karman vortex street가 발생한다. 이러한 vortex가 발생하기 위해서는 기온 역전층과 5 ~ 13 m/s의 지속적인 바람이 필요하다는 것을 밝히기 위한 많은 연구들이 있었다. 이러한 vortex clouds는 발생 후 주 풍향의 방향을 이동하게 된다. Karman vortex street는 기상학에서 매우 흥미로운 주제이다. 본 연구에서는 LES 난류 모델을 이용하여 Karman vortex street에 관한 해석을 수행하고 수치해석을 통해 얻은 결과와 기상 데이터가 일치함을 보였다. From late autumn to the beginning of the spring, the phenomena of the Karman vortex street have been frequently observed in the wake of Mt. Halla in the Jeju island. Some researches revealed that the necessary conditions for development of these vortex clouds are a strong low-level inversion of temperature and a persistent wind speed of 5 to 13m/s. After the cloud is formed, the vortex clouds are shed from alternating sides of Jeju island and then move downwind with main airflow stream. The Karman vortex street in the wake of the Jeju island was one of the interesting topics in meteorology. In this study, CFD using LES turbulence model was developed to investigate the Karman vortex street and the results of CFD showed a good agreement with weather data.

백서에서 MgSO4 와 Bupivacaine 의 지주막하 병용투여에 의해 강화된 진통효과

이광호,이영복,김진수,최재찬,김순열,임현교,전은성,윤경봉 대한마취과학회 2001 Korean Journal of Anesthesiology Vol.41 No.6

배관내에서 자유수면 와동에 관한 연구

김상녕,이종원,오율권,장완호 慶熙大學校 1991 論文集 Vol.20 No.-

During mid­loop operation of nuclear power to prevent the residual heat removal system from failure due to air entrainment of free surface vortex in the piping system a set of simulating experiments was performed. Through these experiments, a relation between the non­dimensionalized numbers, such as submergence H/d. Froude number, Reynolds number, was found. However, the effect of the Reynolds number is not so dominant as that of the Froude number. It was also found that the boundary conditions of the free surface, that is, the perturbation of the free surface due to opening of closing pump and valves have significant effects on the free surface vortex. Futhermore a modified inlet device which reducer type with vortex breaker has strongly been recommended for the prevention of air entrainment.

수박 덩굴마름병 저항성 판별을 위한 SNP 표지인자 탐색

이혜은,홍종필,서혜영,허윤찬,안율균,김진희,김도선 忠北大學校 農業科學硏究所 2015 農業科學硏究 Vol.31 No.2

:Watermelon (Citrullus lanatus) is an important vegetable crop in the world and contains various health promoting compounds including many antioxidants such as lycopene and beta-carotene. Genetic diversity of cultivated watermelon is very narrow, which is one of major factors limiting the improvement of watermelon breeding program. Gummy stem blight (Didymella bryoniae (Auersw.)) is one of the most destructive diseases and causes crown blight, defoliation and fruit rot, resulting in severe production loss in watermelon. Single nucleotide polymorphisms (SNPs), important molecular markers for genetic studies are frequent sequence variation in the plant genome. This study was performed to develop SNP markers related to gummy stem blight resistance from three watermelon lines, one susceptible and two resistant to gummy stem blight. Of them, 22 SNP primers which were sequence information on SNPs derived from comparing a resistant and susceptible line was used for high resolution melt analysis. A total of 14 candidate SNP primers were detected melt temperature difference. These SNP primers can be useful for developing disease resistance-related markers and, therefore, beneficial to watermelon breeding program.

한지형 잔디의 조성시기, 초종 혼합 비율이 잔디 피복에 미치는 영향

심규열(Gyu Yul Shim),김창수(Chang Soo Kim),이성호(Seong Ho Lee1),주영규(Young Kyoo Joo) 한국잡초학회·한국잔디학회 2004 Weed & Turfgrass Science Vol.18 No.4

This study was conducted to find out the effect of sodding and seeding time and rate of seed mixtures on the establishment of cool-season turfgrasses by evaluating the turf coverage rates for two years.<br/> In fall planting, the required establishment period of full coverage(100%) was 1.5 months with a rolled turf sodding(Kentucky bluegrass 100%, Kentucky bluegrass 80%+Perennial ryegrass 20%). The 100% turf establishment was achieved in 7 months with Perennial ryegrass 100%, and 7.5 months by seeding with Kentucky bluegrass 100%(KB100), Kentucky bluegrass 80%+Perennial ryegrass 20%(KB80+PR20), Kentucky bluegrass 70%+Perennial ryegrass 30%(KB70+PR30).<br/> In spring planting, the establishment periods for sod with KB100 or KB80+PR20 were taken one month. However, in the case of seeding, the establishment periods were 3 months, 3.5 months, 3.5 months and 4 months with PR100, KB80+PR20, KB70+PR30, and KB100, respectively. Comparing the turf establishment vigor between fall and spring planting, the vigor was higher in spring planting than in fall planting in both sodding and seeding.<br/> In the case of spring planting, the most proper time for turf establishment was tested on April, May, and June trials. The effect was significant in establishment vigor. The result showed highest on April planting. On May and June trials, establishment vigors were decreased gradually. As the mixture rate of PR increased, ryegrass, establishment vigor was decreased with the rates. These results indicated that perennial ryegrass has relatively less tolerant to summer heat than Kentucky bluegrass.<br/> Number of shoots in 95 days after seeding was higher in KB100 by 16,600 per ㎡ than in PR100 by 12,400 per ㎡, while the lowest number showed in KB50+PR50 by 3,300 per ㎡. Those in KB80:PR20, KB70:PR30 were 6,700 and 4,900 per ㎡, respectively. The ratios of tillers according to mixture rates between Kentucky bluegrass and perennial ryegrass were KB80:PR20=87:13, KB70:PR30=78:22, and KB50:PR50=48:52.<br/> According to results in this study, ideal seeding time might be spring (April) than in fall (September), and proper mixture rate was 80% of Kentucky bluegrass with 20% of perennial ryegrass.

Validation Study of Kim's Smoking Cessation Motivation Scale and Its Predictive Implications for Smoking Cessation

Park, Jae Woo,Chai, Sukhi,Lee, Ju Yul,Joe, Keun-Ho,Jung, Jo Eun,Kim, Dai Jin Korean Neuropsychiatric Association 2009 PSYCHIATRY INVESTIGATION Vol.6 No.4

<P><B>Objective</B></P><P>The purpose of this study was to develop a scale to measure motivation for smoking cessation. Motivation is known to be important for success of smoking cessation. The reliability of the scale was assessed and its predictive validity for smoking cessation was evaluated.</P><P><B>Methods</B></P><P>We recruited 333 men aged 20 to 70 that visited smoking cessation clinics at seven public health centers. The demographic characteristics were recorded and the Korean version of Stages of Readiness for Change and Eagerness for Treatment Scale for Smoking (K-SO-CRATES-S) performed. A smoking cessation motivation scale was developed with 10 questions based on the theory of motivation enhancement therapy.</P><P><B>Results</B></P><P>The motivation scale was composed of four subscales based on the factor analysis; each subscale had an adequate degree of internal consistency. In addition, the newly developed scale had a high degree of validity based on its significant correlation with the smoking version of SOCRATES. Moreover, the precontemplation level of motivation was found to significantly predict the success of smoking cessation. And one of the subscales of the Korean Nicotine Dependence Syndrome Scale (K-NDSS), stereotypy which also significantly predicted the success of smoking cessation, significantly correlated with the preparation 1 and 2 level of motivation.</P><P><B>Conclusion</B></P><P>The smoking cessation motivation scale with 10 questions that was developed in this study was a highly reliable and valid scale for the prediction of success for smoking cessation for those who wanted to stop smoking.</P>

미만성 축삭 손상 환자에서의 예후 인자

음성화,임동준,김봉룡,조태형,박정율,서중근,이기찬,이훈갑 대한신경외과학회 1998 Journal of Korean neurosurgical society Vol.27 No.12

Crack-Release Transfer Method of Wafer-Scale Grown Graphene Onto Large-Area Substrates

Lee, Jooho,Kim, Yongsung,Shin, Hyeon-Jin,Lee, ChangSeung,Lee, Dongwook,Lee, Sunghee,Moon, Chang-Yul,Lee, Su Chan,Kim, Sun Jun,Ji, Jae Hoon,Yoon, Hyong Seo,Jun, Seong Chan American Chemical Society 2014 ACS APPLIED MATERIALS & INTERFACES Vol.6 No.15

<P>We developed a crack-release graphene transfer technique for opening up possibilities for the fabrication of graphene-based devices. Graphene film grown on metal catalysts/SiO<SUB>2</SUB>/Si wafer should be scathelessly peeled for sequent transferring to a target substrate. However, when the graphene is grown on the metal catalyst on a silicon substrate, there is a large tensile stress resulting from the difference of the coefficient of thermal expansion in the catalyst and silicon. The conventional methods of detaching graphene from metal catalysts were found to induce considerable mechanical damage on graphene films during separation processes including metal wet etching. Here we report a new technique wherein bubbles generated by electrolysis reaction separate thin metal catalysts from the SiO<SUB>2</SUB>/Si wafer. The dry attachment of graphene to the target wafer was processed utilizing a wafer to wafer bonding technique in a vacuum. We measured the microscopic image, Raman spectra, and electrical properties of the transferred graphene. The optical and electrical properties of the graphene transferred by the bubbles/dry method are better than those of the graphene obtained by mechanical/wet transfer.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2014/aamick.2014.6.issue-15/am502565z/production/images/medium/am-2014-02565z_0005.gif'></P>