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An Experimental Study on the Melting of Horizontal Ice - Bar Located Concentrically in the Cylinder (수평원관속에 동심으로 놓여있는 얼음 봉의 융해현상에 관한 보험적 연구)

  • Lee, Dong-Wook;Yoo, Sang-Sin
    • The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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    • v.15 no.2
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    • pp.196-203
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    • 1986
  • The melting phenomena of horizontal cylindrical ice-bar immersed in water and air concentrically in the cylinder are experimentally investigated for the temperature range from $3.5^{\circ}C\;to\;2.5^{\circ}C$. The shapes of the melting ice-bar are recorded photographically by the shadowgraph method. The shadowgraphs of the melting ice-bar show that water adjacent to the bar flows upward for the temperature range from $3.5^{\circ}C\;to\;5.8^{\circ}C$ while above $5.8^|\circ}C$ the flow is downward direction. The local and average Nusselt numbers are obtoined with the recorded shadowgraphs and comparator. Melting shapes of the ice-bar in the air show the vortex motion in the bottom portion of the bar, whereas no vortex motion appears in the bottom portion when the bar is melted in the water.

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ON INTEGRAL MEANS OF DERIVATIVES OF UNIVALENT FUNCTIONS

  • Elhosh, M.M.
    • Bulletin of the Korean Mathematical Society
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    • v.24 no.1
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    • pp.13-17
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    • 1987
  • Let S denote the class of nivalent functions normalized so that f(0)=f'(0)-1=0 in vertical bar z vertical bar <1. Let $S_{\alpha}$$^{*}$, -.pi./2<.alpha.<.pi./2, denote the subclass of S that satisfies Re $e^{i{\alpha}}$zf'(z)/f(z).geq.0 in vertical bar z vertical bar <1; then f is called .alpha.-spiral-like and the case .alpha.=0 is the class of normalized starlike functions [6, pp.52]. Let T denote the class of functions f normalized as above and satisfying Im z[Im f(z)]..geq.0 in vertical bar z vertical bar <1; then f is called typically real and T contains those functions of S whose coefficients are real [6, pp.55]. Also, in view of [6, pp.231], let B(.lambda.) be the class of function normalized as above and map vertical bar z vertical bar <1 onto the complement of an arc with radial angle .lambda.(0<.lambda.<.pi./2). The radial angle is meant to be the angle between the tangent and radial vectors to the arc. This note includes a sharp version for Corollary 1 of [2] when f.mem. $S_{\alpha}$$^{*}$ as well as a logarithmic coefficient estimate.nt estimate.

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Performance of headed FRP bar reinforced concrete Beam-Column Joint

  • Md. Muslim Ansari;Ajay Chourasia
    • Structural Engineering and Mechanics
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    • v.90 no.1
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    • pp.71-81
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    • 2024
  • Fiber Reinforced Polymer (FRP) bars have now been widely adopted as an alternative to traditional steel reinforcements in infrastructure and civil industries worldwide due variety of merits. This paper presents a numerical methodology to investigate FRP bar-reinforced beam-column joint behavior under quasi-static loading. The proposed numerical model is validated with test results considering load-deflection behavior, damage pattern at beam-column joint, and strain variation in reinforcements, wherein the results are in agreement. The numerical model is subsequently employed for parametric investigation to enhance the end-span beam-column joint performance using different joint reinforcement systems. To reduce the manufacturing issue of bend in the FRP bar, the headed FRP bar is employed in a beam-column joint, and performance was investigated at different column axial loads. Headed bar-reinforced beam-column joints show better performance as compared to beam-column joints having an L-bar in terms of concrete damage, load-carrying capacity, and joint shear strength. The applicability and efficiency of FRP bars at different story heights have also been investigated with varying column axial loads.

A Study of the Academic Perspective of Chang Seok Sun (장석순(張錫純)의 학술사상에 관한 연구)

  • Woo, Ho;Park, Hyun-kuk
    • The Journal of Dong Guk Oriental Medicine
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    • v.7 no.1
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    • pp.1-32
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    • 1998
  • I found following idea, as a result of researching his Science idea, mainly, by translation of the "$Zh\bar{a}ng$ xi $ch\acute{u}n$ $Xu\acute{e}$ $Sh\acute{u}$ ssu $hsi\acute{a}ng$ "(張錫純 學術硏究). $Zh\bar{a}ng$ xi $ch\acute{u}n$ regarded $ch\tilde{u}ng$ $ch\bar{u}ng$ $ts'\bar{a}n$ $hs\bar{l}$' (衷中參西) as the core idea of The Chinese-Western medical combination. He didn't segregate philosophy of the West from One of the Orient. He persued to harmonize each other and thought that the Western medicint theory is included in the Chinese one in many parts. besides, He recognized that it is bad to reject each other, for the medical science's purpose is to save a life, and united The Chinese-Western medicine theory, by $ch\acute{u}ng$ $ch\tilde{u}ng$ $ch\bar{u}ng$ $ts'\bar{a}n$ $hs\bar{l}$'(衷中參西) idea which refers to consult the Western medicine on the basis of the Chinese one. Medical basic theory of $Zh\bar{a}ng$ xi $ch\acute{u}n$ brought up new views of the theory : Dae-gi(大氣), gi-Hwa(氣化) theory, Nongangubgan byung juing chi(論肝及肝病證治), Eum her chijung ja bi(陰虛治重滋脾). Lim Sangeung yong(臨床應用) of Hyul Her gub(血虛及)-Hwal Hyul Hwa $\breve{u}$ bub(活血化瘀法), on the basis of classics, such as, "$N\breve{e}i$ Ching"(內經), "Chin Kue $\breve{i}$ $y\bar{a}o$ $l\ddot{u}{\bar{e}}h$, "Shen $n\acute{u}ng$ $p\breve{e}n$ $t\acute{s}{\check{a}}o$ ching"(新農本草經) etc. I'll sum up $Zh\bar{a}ng$ xi $ch\acute{u}n's$ clinical idea now He unified Sang Han(像寒)-On Byung(溫病) with Yuk Kyung Byung Jung(六經辨證) and It was noticiable to utilize a kinds of Baek Ho Tang(白虎湯). He gave a detailed description about a method of grasp the symptoms of the cause of the internal medicine diseases and pathology and, he left abundant views of theory about using remedy and experience of clinic.

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The Research Status and Task of the Metalcrafts of Shoso-in Collection (정창원(正倉院) [쇼소인] 금속공예의 연구 현황과 과제)

  • Choi, Eungchon
    • Korean Journal of Heritage: History & Science
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    • v.51 no.3
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    • pp.32-53
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    • 2018
  • The $Sh{\bar{o}}s{\bar{o}}-in$(正倉院) is the detached storage building for Japanese treasures that belongs to $T{\bar{o}}dai-ji$ in Nara, Japan. The reason why $Sh{\bar{o}}s{\bar{o}}-in$ collections are drawing attention is that Japanese artifacts, sculptures, paintings, and other objects that were introduced through the Silk Road, such as Sasanian Persia and India, and those that were introduced from the Unified Silla and Tang China. In addition, hundreds of well-preserved documents of $Sh{\bar{o}}s{\bar{o}}-in$ collections play an important role as a historical reference material covering not only the social situation of the time but also the history of exchange of cultural diplomacy and the change of Buddhist doctrine. In particular, some of collections of $Sh{\bar{o}}s{\bar{o}}-in$ were made in China and may have been imported or received as gifts, but many of the artifacts made in Baekje and Unified Silla are becoming more and more important. This paper examined the research status of $Sh{\bar{o}}s{\bar{o}}-in$ metal crafts of Korean and foreign scholars, and examined the association with the relics of $Sh{\bar{o}}s{\bar{o}}-in$ through metal crafts excavated from the Korean Peninsula. The research on the future direction of $Sh{\bar{o}}s{\bar{o}}-in$ collections should be summarized as follows. 1. Systematization of state-level support and single window for the research of $Sh{\bar{o}}s{\bar{o}}-in$ collections 2. Accurate listing and database of $Sh{\bar{o}}s{\bar{o}}-in$ collections 3. The positive implementation of joint research with Japan and invitation of researchers related to $Sh{\bar{o}}s{\bar{o}}-in$ collections 4. The exchange exhibition between the Korean National Treasures and the $Sh{\bar{o}}s{\bar{o}}-in$ collections 5. Expansion of the research base through the publication and support of books related to $Sh{\bar{o}}s{\bar{o}}-in$ collections.

THE EFFECT OF GINGIVAL GEL ON PERIODONTIUM IN MANDIBULAR FRACTURE PATIENTS APPLIED BY ARCH BAR (선부자를 적용한 하악골 골절환자의 치주조직에 기능성 치약이 미치는 영향)

  • Kim, Sun-Min;Kim, Kyung-Wook
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.35 no.2
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    • pp.125-130
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    • 2009
  • For many years, intermaxillary fixation using arch bar has been operated in treatment of mandibular fracture patients. But it has many complications including injury of operators and assistants cause by wire, inflammation of periodontium. For that reasons alternatives are required; osteosynthesis technique using mini plate, intermaxillary fixation using IMF screws have been available. Treatment by arch bar fixation, however, is still valuable to treat craniomaxillary fracture patients. The purpose of this study is to know effect arch bar on periodontium and influence gingival gel on periodontium applied by arch bar. 40 mandibular fracture patients are monitored. 30 patients were applied by arch bar, 10 patients were not. And the former were classified by 3 categories; Nano vitamin and Mastic gel were applied to 10 patients respectively and any gingival gel was not used to 10 patients. Clinical attachment level, bleeding on probing and periodontal depth of each group were measured and compared before operation and on 2 weeks and 6 weeks after operation. Mann-Whitney U test was used to analyze result which leads to this conclusion. 1. Whether arch bar is applied or not, treatment of mandlbular fracture gave rise to gingivitis, but 6 weeks after operation, gingivitis is restored to the same level as the state before operation. 2. More severe gingivitis appeared when arch bar is applied to mandibular fracture than when it is not. 3. Both gingival gel used in this study can reduce gingivitis which can be caused by arch bar. 4. In this study, Mastic gel is more effective for prevent gingival inflammation cause by arch bar than nano vitamin. In regard to this result, gingivitis is considered to be available because it is reversible and does not induce periodontal disease. Gingival gel is regarded to be helpful for patients applied by arch bar to feel less discomfort.

Experimental Investigations on the Flexural Behavior of One-Way Concrete Slabs Reinforced with GFRP Re-Bar Bundle (유리섬유 보강 플래스틱 Re-Bar 다발로 보강된 1방향 콘크리트 슬래브의 휨거동에 관한 실험적 연구)

  • 윤순종;김병석;유성근;정재호;정상균
    • Composites Research
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    • v.16 no.3
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    • pp.32-40
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    • 2003
  • In recent years, the investigation on the development of fiber reinforced plastic(FRP) Re-Bar has been greatly increased due to the attractive physical and mechanical properties of FRP. The primary reason of such a tendency is in the fact that it does not ordinarily cause durability problems such as those associated with steel reinforcement corrosion. This study is an experimental investigation on the flexural behavior of one-way concrete slabs, which can be used to construct bridge deck, reinforced with GFRP Re-Bar bundle. The tensile tests of GFRP Re-Bar produced by domestic industry and third point bending tests of one-way slab specimens reinforced with GFRP Re-Bar bundle are peformed. For all slab specimens, load-deflection relations are predicted by using the ACI committee 440 and the results are compared with experimental ones. In order to establish the design criteria or guidelines of concrete flexural member reinforced with FRP Re-Bar, it is needed to evaluate the serviceability limit state as well as the strength limit state.

Acid Etching of Sapphire Substrate for Hetero-Epitaxial Growth (Hetero-Epi막 성장용 사파이어 기판의 산에칭)

  • Kim, Hyang Sook;Hwang, Jin Soo;Chong, Paul Joe
    • Journal of the Korean Chemical Society
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    • v.39 no.1
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    • pp.1-6
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    • 1995
  • The surface of a sapphire substrate used for hetero-epitaxy was chemically polished in a mixture of $H_3PO_4\;and\;H_2SO_4$ solution. The extent of etching for various crystal orientations was found to be dependent on the etching time at $315{\pm}2^{\circ}C$ and at the composition of $H_2SO_4 : H_3PO_4$=3 : 1. In addition, the etching rates of the substrates were investigated in the mixture of $H_2SO_4 : H_3PO_4$=3 : 1 by volume and in the temperature range of 280~320$^{\circ}C$. From the plot of log R against 1/T, the activation penergy ($(E_a)$) was found to be in the order of $({\bar1}012) > (10{\bar1}0) > (11{\bar2}0) > (0001)$ plane. After removing the surface layers of the sapphire with (0001), $({\bar1}012),\;(10{\bar1}0)\;and\;(11{\bar2}0)$ plane by a thickness of 64.6, 46.5, 16.2 and 5.1 ${\mu}m$, respectively, the morphology of the resulting surface was observed by SEM.

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A THREE DIMENSIONAL PHOTOELASTIC STRESS ANALYSIS OF IMPLANT-SUPPORTED MANDIBULAR OVERDENTURE ACCORDING TO IMPLANT NUMBER AND ATTACHMENT TYPE (임플란트의 수와 어태치먼트의 종류에 따른 하악 임플란트 지지 오버덴춰의 삼차원 광탄성 응력분석)

  • Han, Sang-Hoon;Tae, Yoon-Sup;Jin, Tae-Ho;Cho, Hye-Won
    • The Journal of Korean Academy of Prosthodontics
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    • v.35 no.3
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    • pp.577-608
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    • 1997
  • The purpose of this study is to evaluate the stress distribution in the bone around dental implants supporting mandibular overdenture according to the number of implant and the type of attachment. Two or four implants were placed in an edentulous mandibular model and three dimensional photoelastic stress analysis was carried out to measure the fringe order around the implant supporting structure and also to calculate principal stress components at cervical area of each implant. The attachments tested were rigid and resilient type of Dolder bar, Round bar, Hader bar and Dal-Ro attchment. The results were as follows ; 1. In 2-implant supported overdenture using Round bar, Hader bar, and Dal-Ro attachment, compressive stress pattern was observed on the supporting structure of implant on loaded side, while tensile stress pattern in unloaded side. 2. In 2-implant supported overdenture using Dolder bar, the rigid Dolder bar shared the occlusal loads between 2 implants in a more favorable manner than was exhibited by the resilient type, while the resilient type placed a more stress on the distocervical area of the implant on the loaded side. But compressive stress pattern was observed in both the loaded and unloaded sides in either case. 3. In 2-implant supported overdenture, rigid and resilient type of Dolder bar exhibited more cross arch involvement than the Round bar, Hader bar, or Dal-Ro attachment. 4. In 4-implant supported overdenture using resilient Dolder bar and Hader bar, stress turned out to be distributed evenly among the implants between loaded and unloaded side, but thor was no reduction in the magnitude of the stress in the surrounding structure of implant contratry to 2-implant supported overdenture. 5. The stress pattern at cervical area of implant was different with the number of implant or the type of attachment but the overload, harmful to surrounding structure of implant, was not observed.

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A Clinical Trial on Efficacy of Gagamchengyoung-tang(Jiājiǎnqīngyíng-tāng) in the Alopecia Patients with Febrile Tendency (열성 탈모환자에 대한 가감청영탕(加減淸營湯) 효과의 임상적 연구)

  • Hong, Jung-Ae;Kang, Su-Jin;Jang, Jin-Young;Kang, Yeo-Reum
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.26 no.2
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    • pp.19-29
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    • 2013
  • Objectives : The main purpose of this study is to investigate the efficiency of Gagamchengyoung-tang (Ji$\bar{a}$ji$\check{a}$nq$\bar{i}$ngy$\acute{i}$ng-t$\bar{a}$ng) and examine the febrile tendency in the alopecia patients Methods : Of the patients who have visited Balmers Korean Medicine clinic for alopecia from December first 2012 to December 31st 2012, we enrolled 30 patients and performed heat and cold diagnosis, examine scalp and check hair density. We administrated Gagamchengyoung-tang(Ji$\bar{a}$ji$\check{a}$nq$\bar{i}$ngy$\acute{i}$ng-t$\bar{a}$ng) and acupuncture to all patients. The effect was assessed by scalp condition and hair density Results : The scalp disorder index decreased and hair density increased in alopecia patients with febrile tendency Conclusions : All patients had febrile tendency and Gagamchengyoung-Tang(Ji$\bar{a}$ji$\check{a}$nq$\bar{i}$ngy$\acute{i}$ng-t$\bar{a}$ng) can be effective in the scalp disorder and alopecia.