• Title/Summary/Keyword: Back-surface shape

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A Study on the Corrosion Prevention of the Integral Series Generator for Military Vehicles (군용차량용 엔진일체형 직렬 발전기 부식 방지에 관한 연구)

  • Kang, Tae-Woo;Kim, Seong-Gon;Shin, Cheol-Ho;Lee, Kye-Sub
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.6
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    • pp.74-79
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    • 2019
  • The military vehicle produces electric power through an engine-integrated serial hybrid generator that is connected to the engine and does not have a separate generator installation space. However, depending on the mechanical characteristics of the connection between the generator and the engine, iron oxide for internal rusting and lubrication grew scattered. The iron oxide is adhered to the starter to deteriorate the starting performance, and there is a problem that the noise of the leg due to wear of the gear is increased. To solve this problem, the connection spline material and the surface treatment of the engine were improved and the shape was changed to a grease sealing type to prevent the generation of iron oxide inside. As the shape of the generator connector composing the shafting system was changed, the integrity of the structure was confirmed through the torsional endurance test. In addition, through the actual vehicle load test, it was verified that no corrosion occurred during the target life span without internal corrosion. It was confirmed that the anti-scattering structure of the grease effectively suppresses the generation of iron oxide, thereby reducing the noise generated from the generator. In this paper, we propose a fundamental solution to the degradation of the starter and the noise generation by preventing the back corrosion caused by the serial hybrid generator installed between the engine and the transmission.

Transport behavior of a surfactant tracer(CPC) with Langmuir type adsorption isotherm on NAPL-water interface in a homogeneous porous medium (NAPL-물 계면에서 Langmuir형 흡착특성을 보이는 계면추적자(CPC)의 다공성 균질매질내 유동특성)

  • 김헌기;문희수;이상훈
    • Journal of Soil and Groundwater Environment
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    • v.6 no.2
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    • pp.3-13
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    • 2001
  • It has been known that nonlinear characteristics of sorption affect the transport behavior of water soluble pollutants in soils. However detailed experimental studies have not been performed to verify the effect of non-linearity of adsorption isotherm on transport of chemicals in porous media. In this research, the distortion of breakthrough curves of a cationic surfactant (cetylpyridinium chloride, CPC) in a engineered stainless steel column packed with glass beads were investigated. Glass beads with about 110 $\mu\textrm{m}$diameter coated with a thin n-decane film were used as the media providing the sorption surface for CPC. The CPC adsorption isotherm on the surface of n-decane from aqueous solution was a typical Langmuir type. The breakthrough curve of CPC using step Input showed a late breakthrough on the front side and early breakthrough on the back side accordance to the shape of the isotherm. The retardation factor of CPC was found to be a strong function of the input concentration, which also a manifestation of the non-linearity of the isotherm. The retardation factors for the CPC with step input agreed with those of pulse input that the maximum concentrations are controlled to be the same as the step input concentrations. This results support the validity of the unproven field practices of using hydrogeotracers with non-linear adsorption isotherms to determine the hydrogeological parameters, e.g., NAPL saturation, air-water or NAPL-water interfacial areas.

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Development of On-line Quality Sorting System for Dried Oak Mushroom - 3rd Prototype-

  • 김철수;김기동;조기현;이정택;김진현
    • Agricultural and Biosystems Engineering
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    • v.4 no.1
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    • pp.8-15
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    • 2003
  • In Korea, quality evaluation of dried oak mushrooms are done first by classifying them into more than 10 different categories based on the state of opening of the cap, surface pattern, and colors. And mushrooms of each category are further classified into 3 or 4 groups based on its shape and size, resulting into total 30 to 40 different grades. Quality evaluation and sorting based on the external visual features are usually done manually. Since visual features of mushroom affecting quality grades are distributed over the entire surface of the mushroom, both front (cap) and back (stem and gill) surfaces should be inspected thoroughly. In fact, it is almost impossible for human to inspect every mushroom, especially when they are fed continuously via conveyor. In this paper, considering real time on-line system implementation, image processing algorithms utilizing artificial neural network have been developed for the quality grading of a mushroom. The neural network based image processing utilized the raw gray value image of fed mushrooms captured by the camera without any complex image processing such as feature enhancement and extraction to identify the feeding state and to grade the quality of a mushroom. Developed algorithms were implemented to the prototype on-line grading and sorting system. The prototype was developed to simplify the system requirement and the overall mechanism. The system was composed of automatic devices for mushroom feeding and handling, a set of computer vision system with lighting chamber, one chip microprocessor based controller, and pneumatic actuators. The proposed grading scheme was tested using the prototype. Network training for the feeding state recognition and grading was done using static images. 200 samples (20 grade levels and 10 per each grade) were used for training. 300 samples (20 grade levels and 15 per each grade) were used to validate the trained network. By changing orientation of each sample, 600 data sets were made for the test and the trained network showed around 91 % of the grading accuracy. Though image processing itself required approximately less than 0.3 second depending on a mushroom, because of the actuating device and control response, average 0.6 to 0.7 second was required for grading and sorting of a mushroom resulting into the processing capability of 5,000/hr to 6,000/hr.

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Tissue Engineered Cartilage Formation on Various PLGA Scaffolds (PLGA 종류와 담체의 형성 방법에 따른 인간의 조직공학적 연골형성)

  • 김유미;임종옥;정호윤;박태인;백운이
    • Journal of Biomedical Engineering Research
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    • v.23 no.2
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    • pp.147-153
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    • 2002
  • The purpose of this study was to evacuate the effect of different types of Poly(lactic-co-glycolic acid) (PLGA) scaffolds on the formation of human auricular and septal cartilages. All of the scaffolds were formed in a tubular shape for potential application for artificial trachea or esophagus with either 110,000 g/mol PLGA. 220,000 g/mol PLGA. or a combination of both. In order to maintain the tubular shape in vivo, two methods were used. One method was inserting polyethylene tube at the center of scaffolds made of 110,000 g/mol PLGA. The other method involved combination of the two different molecular weight PLGA's. The inner surface of tubular shaped scaffold made with 110,000 g/mol PLGA was coated with 220,000 9/mol PLGA to give more mechanical rigidity. Elastic cartilage was taken from the ear of a patient aged under 20 nears old and hyaline cartilage was taken from the nasal septum. The chondrocytes were then isolated. After second passage, the chondrocytes were seeded on the PLGA scaffolds followed by in vitro culture for one week. The cells-PLGA scaffold complex were implanted subcutaneously on the back of nude mice for 8 weeks. The tissue engineered cartilages were separated from nude mice and examined histologically after staining with the Hematoxylin Eosin. The morphology of the scaffolds were examined by scanning electron microscopy. The pores were well formed and uniformly distributed in the various PLGA scaffolds. After 8 weeks in vivo culture, cartilage was well formed with 110,000 g/mol PLGA. however lumen had collapsed. In contrast. a minimal amount of neocartilage was formed with 220,000 g/mol PLGA, while the architecture of scaffold and lumen were well preserved. Elastic cartilage formed more neocartilage than hyaline. Hyaline and elastic neocartilage were well formed on 110,000 g/mol PLGA with the polyethylene tube, exhibiting mature chondrocytes and preservation of the tubular shape. It was found that 110,000 g/mol PLGA was more appropriate for cartilage formation but higher molecular weight polymer was necessary to maintain the three dimensional shape of the scaffold.

A Study on the Excavated Sab(a funeral fan) from Lime-filled Tomb and Lime-layered Tomb during the Joseon Dynasty (조선시대 회격·회곽묘 출토 삽(翣)에 대한 고찰)

  • Yi, Seung Hae;An, Bo Yeon
    • Korean Journal of Heritage: History & Science
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    • v.41 no.2
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    • pp.43-59
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    • 2008
  • Sap(?, a funeral fan) is a funeral ceremonial object used in association with a Confucian ceremonial custom, which was crafted by making a wooden frame, attaching a white cloth or a thick paper onto it, drawing pictures on it, and making a holder for a handle. According to Liji(Records of Rites), Sap was used since the Zhou Dynasty, and these Chinese Sap examples are no big different than the Korean Sap examples, which were described in Joseon Wangjo Sillok(Annals of the Joseon Dynasty), Gukjo Oryeui(the Five Rites of the State), and Sarye Pyeollam(Handbook on Four Rituals). This study explored Sap excavated in lime-filled tombs and lime-layered tombs of aristocrats dating back to Joseon, as well as their historical records to examine Sap's characteristics according to their examples, manufacturing methods, and use time. The number and designs of Sap varied according to the deceased' social status aristocrats used mainly one pair of 亞-shaped Bulsap, and a pair of Hwasap with a cloud design depicted on it. A Sap was wrapped twice with Chojuji paper or Jeojuji paper, and for the third time with Yeonchangji paper. Then, it was covered with a white ramie, a hemp, a cotton, a silk satin, etc. Bobul(an axe shape and 亞-shape design) was drawn on both sides of Sap, and a rising current of cloud was drawn at the peripheral area mainly with red or scarlet pigments. Sap, which were excavated from aristocrats'lime-filled and lime-layered tombs, are the type of Sap which were separated from its handle. These excavated Sap are those whose long handles were burnt during the death carriage procession, leaving Sap, which later were erected on both sides of the coffin. The manufacturing process of excavated relics can be inferred by examining them. The excavated relics are classified into those with three points and those with two points according to the number of point. Of the three-point type(Type I), there is the kind of relic that was woven into something like a basket by using a whole wood plate or cutting bamboo into flat shapes. The three-point Sap was concentrated comparatively in the early half of Joseon, and was manufactured with various methods compared with its rather unified overall shape. In the meantime, the two-point Sap was manufactured with a relatively formatted method; its body was manufactured in the form of a rectangle or a reverse trapezoid, and then its upper parts with two points hanging from them were connected, and the top surface was made into a curve(Type II) or a straight line(Type III) differentiating it from the three-point type. This manufacturing method, compared with that of the three-point type, is simple, but is not greatly different from the three-point type manufacturing method. In particular, the method of crafting the top surface into a straight line has been used until today. Of the examined 30 Sap examples, those whose production years were made known from the buried persons'death years inscribed on the tomb stones, were reexamined, indicating that type I was concentrated in the first half of the $16^{th}$ century. Type II spanned from the second half of the $16^{th}$ century to the second half of the $17^{th}$ century, and type III spanned from the first half of the $17^{th}$ century to the first half of the $18^{th}$ century. The shape of Sap is deemed to have changed from type I to type II and again from type II to type III In the $17^{th}$ century, which was a time of change, types II and III coexisted. Of the three types of Sap, types II and III re similar because they have two points; thus a noteworthy transit time is thought to have been the middle of the $16^{th}$ century. Type I compared with types II and III is thought to have required more efforts and skills in the production process, and as time passed, the shape and manufacturing methods of Sap are presumed to have been further simplified according to the principle of economy. The simplification of funeral ceremonies is presumed to have been furthered after Imjinwaeran(Japanese invasion of Joseon, 1592~1598), given that as shown in the Annals of King Seonjo, state funerals were suspended several times. In the case of Sap, simplification began from the second half of the $16^{th}$ century, and even in the $18^{th}$ century, rather than separately crafting Sap, Sap was directly drawn on the coffin cover and the coffin. However, in this simplification of form, regulations on the use of Sap specified in Liji were observed, and thus the ceremony was rationally simplified.

Development of Depositional Landforms in Upstream Reach of Ulsan Sayeon Dam Lake (울산 사연호 상류의 퇴적지형 발달)

  • Chang, Mun-Gi
    • Journal of the Korean association of regional geographers
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    • v.13 no.4
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    • pp.409-421
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    • 2007
  • The purpose of this paper is to consider the formation processes and depositional conditions of bars formed at the upper-stream part of Sayeon Dam since Sayeon Dam construction in 1964. Results of analyzing the shape characteristics of bars and their sediment grain size distribution are as follow: Firstly, bars are able to categorized as subaqueous bars (A, B), mid-channel bars(C, D), and tributary side-bars(E). Secondly, the outline of bars has longish along the flow path, and their height lowers more and more going towards downstream. Also the height of bar surface tend to heighten from flow path to mountain slope. However, the near part of A is comparatively higher than its distant part, A is defined as a subaqueous natural levee and back swamp. Thirdly, the average particle size of A and B become smaller toward mountain slope. In transportation style, ratio of suspended load become higher toward mountain slope. Fourthly, sorting is worse to very worse according with lake's random changable water level. Fifthly, bar A and B were formed by vertical sedimentation of sediments according as sediments transported along flow path in the subaqueous conditions were spreaded out of flow path. C and D were formed by bed load as flood level lowered. And E was formed by vertical sedimentation while stream flow stopped in tributary's mouth areas with the water level heightening.

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The Influence of Arshile Gorky's & Jackson Pollock's Painting on Modern Fashion (Arshile Gorky와 Jackson Pollock의 Painting이 현대의상 직물 문양에 미친 영향)

  • Chung Heungsook Grace
    • Journal of the Korean Society of Clothing and Textiles
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    • v.16 no.3 s.43
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    • pp.197-207
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    • 1992
  • Expressionism, is as diverse as the artists invo)ved, in a very broad sense two main tendencies may be noted. The first is that of the Action painters, concerned in different ways with the gesture of the brush and the texture of the paint. It included such major artists as Arshile Gorky, Jackson Pollock, Willem De Keening, and Franz Kline. The other group consisted of the Color Field painters, concerned with the statement of an abstract sign or tranquil image in terms of a large, unified color shape or area. Here must be included Mark Rothko, Barnett Newman, Ad Rdinhardt, as well as, to a degree, Adolph Gottlieb, Robert Motherwell, and Clyf(ord Still. In this paper, 1 selected two artists Arshile Gorky and Jackson Pollock independent charac-teristics and studied the influence of their Action painting on the fabrics of modern fashion. However, it should be noted it was never the intention of the critic Harold Rosenberg, in coining this term, to imply that Action painting was a kind of athletic exercise. Nor is it true that the furious and seemingly haphazard scattering of the paint involved a completely uncontrolled, intuitive act. There is no question that, in the paintings of Jackson Pollock, Arshile Gorky and many of the other Abstract Expressionists, the element of intuition or the accidental plays a large and deliberate part; this was indeed one of the principal contributions of Abstract Expressionism which had found its own inspiration in surrealism's 'psychic automaton'. However, nothing that an experienced and accomplished artist does can be completely accidental. Aside from their intrinsic quality, the spun-out skeins of poured pigments contributed other elements that changed the course of modern painting. There was the concept of the all-over painting, the painting seemingly without beginning or end, extending to the very limits of the canvas and implying an extension even beyond. The feeling of absorption or participation is heightened by the ambiguity of the picture space. The colors and lines, although never punctur-ing deep perspective holes in the surface, still create an illusion of continuous movement, a billowing, a surging back and forth, within a limited depth. To study the influence of Abstract Expressionism on the fabric of modern fashion, 1 selected and examined four fashion magazines: Collezioni published in France, Bazaar in Italy, Gap in Japan and Vogue in the U.S.a. froim January 1989 to June 1991. As a result of this review I found that some fabrics used in modern clothing are printed in a dripping, pouring and splashing style without any meaning or form. Slides included in the presentation show that modern fabrics which are printed in such a style were influenced by Abstract Expressionism. The slides also show that these abstract prints are well suited to modern fashion design.

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Biomimetic Analysis on the Spider Silk Apparatus for Designing the Nanofiber-spinning Nozzle (나노섬유 방사노즐 설계를 위한 거미 실크 방적장치의 생체모사 분석)

  • Moon, Myung-Jin;Kim, Hoon;Park, Jong-Gu
    • Applied Microscopy
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    • v.42 no.2
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    • pp.67-76
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    • 2012
  • The biomimetic approach on the cuticular spinning nozzles of the major ampullate silk glands in the golden-web spider Nephila calvata has been attempted using various visualizing techniques of light and electron microscopes to improve the design of spinning nozzle for producing synthetic nanofibers spun from electrospinning apparatus. The major ampullate spigot which has the most effective nozzle system to produce nanofibers for dragline silk with high strength and elasticity is connected via the bullet type spigot on anterior spinneret with flexible terminal segment. The excretory duct which transports the liquid silk feedstock from ampulla to spigot is divided into 3 limbs by loops back on itself to form an S-shape morphology that is bundled in connective tissue. Final diameter of the nanofibers at nozzle was dramatically reduced by gradual narrowing of duct cuticle less than 10 times comparing to its original size of funnel region. Moreover, the funnel has a characteristic cuticular organization with porous microstructure which seems to be related to water removal from feedstock of silk precursors. High magnification electron micrographs also reveal the presence of the spiral grooves on the surface of the cuticular intima near the valve which presumed to reduce friction during rapid flow of liquid silk.

Convergence Comparison of Linear Oscillating Electric Machines (리니어 오실레이팅 전기기기의 비교 연구)

  • Jeong, Sung-In;Eom, Sang In
    • Journal of the Korea Convergence Society
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    • v.12 no.12
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    • pp.273-280
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    • 2021
  • This paper presents the results of study of linear oscillating electric machine; Cartesian, cylindrical type with permanent magnet, flux reversal, cylindrical reluctance, and transverse flux type. The focus of the work is the suggestion of the characteristics and design process of propose topology, respectively. First of all, there are five types of the proposed to this study on the basis of the existing literatures; Cartesian type, cylindrical type, flux reversal type, cylindrical reluctance type, and transverse flux type. All topology is achieved using equivalent magnetic circuit considering leakage elements as initial modeling. Cartesian type is investigated by number of phases and number of pole pairs using optimal process. A cylindrical type is described by number of phases and displacement of stroke. The flux reversal type is proposed based on the symmetrical and non symmetrical stator cores of the surface mounted PMs mover, and non slanted PMs and slanted PMs of the flux concentrating PMs mover. A cylindrical reluctance type is studied by the shape of mover teeth in geometric aspect to reduce force ripple and increase magnetic flux. A transverse flux type is considered by dividing the transverse flux electric excited and the transverse flux permanent magnet excited. It is significant that the study gives a design rules and features of linear oscillating electric machine.

Surface Deterioration Diagnosis of Taejong Heonreung Sindobi Monument using Nondestructive Method (비파괴 기법을 이용한 태종 헌릉 신도비의 표면 훼손도 진단)

  • Lee, Myeong-seong;Park, Sung-mi;Chun, Yun-gun;Lee, Sun-myung;Lee, Jae-man
    • Korean Journal of Heritage: History & Science
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    • v.46 no.4
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    • pp.90-107
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    • 2013
  • The Stone Monument of Taejong King in Heonreung Royal Tomb, Seoul was originally erected in 1424 to pay a tribute to Bang Won Lee's achievement who was named Taejong, the Third King of Joseon Dynasty. The monument has been damaged by Japanese Invasion of Korea in 1592 so that another monument was newly made and erected together with the original monument in 1695. The original monument was made of medium-grained biotite granite for the turtle base and medium-grained milky white crystalline limestone for the stele body and the top stone. The turtle base of the original monument is destroyed beyond the original shape and inscription due to irregular shaped breaking and a set of longitudinal crack. Analyzing the deterioration degree by using nondestructive methods, the 88 percentage of the front area and 38 percentage of the back area of the monument are damaged, and the lower part of the stele body is dominantly deteriorated especially due to the combination of discoloration and physical deterioration. The new monument in 1695 is also made of granite and limestone. The weathering indices of the turtle base and stele body stones by the calculation from ultrasonic velocity are 0.10 and 0.74, respectively. This is because the original monument is presumed to be degraded by heat shock and physical attack during the Japanese war, and the long-term outdoor exposure accelerated the weathering of the monument afterward without protective shelter.