• 제목/요약/키워드: Elongated structure

검색결과 136건 처리시간 0.03초

Preparation of TZM Alloys Having Elongated Coarse-grain Structure with High Aspect Ratio and their Mechanical Properties

  • Toyosima, Gouhei;Nagae, Masahiro;Yoshio, Tetsuo;Takada, Jun;Hiraoka, Yutaka;Takida, Tomohiro
    • 한국분말야금학회:학술대회논문집
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    • 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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    • pp.1163-1164
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    • 2006
  • TZM alloy having elongated coarse-grain structure was developed by three-step internal nitriding treatment at 1423 to 1873 K in $N_2$ and subsequent recrystallization treatment at 2173 K in vacuum. Some specimens were subjected to re-nitriding treatment at 1873 K for 16 h. After the recrystallization treatment, aspect ratio (L/W) of grains for rolling direction was about 50 at the maximum. Yield stress obtained at 1773 K after re-nitriding treatment was about 6 times as large as that of recrystallized specimen. Re-nitriding was very effective in the improvement in strength of TZM alloy having elongated coarse-grain structure.

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CdSe 나노 입자의 이방성 구조 제어 및 특성연구 (Preparation and Characteristics of Elongated CdSe nanoparticles)

  • 김신호;박명국;김양도
    • 한국분말재료학회지
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    • 제15권3호
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    • pp.210-213
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    • 2008
  • Elongated CdSe nanoparticles with a diameter of 3-7nm have been successfully synthesized using two surfactants of trioctylphospine (TOP) and hexadecylamine (HDA) at $160^{\circ}C$. The formation of elongated CdSe nanoparticles is possibly due to the cooperative effects from both the different binding capability of two surfactants (TOP and HDA) and intrinsically anisotropic crystal structure of the CdSe. The electron diffraction pattern of CdSe nanoparticles revealed the formation of wurzite phase. The CdSe samples showed red-shifted wavelength from 560 to 580nm with increasing the refluxing time due to the gradual growth of CdSe nanoparticles. The relatively broad absorption band can be attributed to the surface state of CdSe nanoparticles. The possible formation mechanism of elongated CdSe nanoparticles was proposed and the characteristics of CdSe have been discussed as well.

이상경상돌기증의 치험례 (A CASE OF SURGICAL TREATMENT FOR SYMPTOMATIC ELONGATED STYLOID PROCESS)

  • 김창환;김은관;박효상;박노부;이용오
    • Maxillofacial Plastic and Reconstructive Surgery
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    • 제16권3호
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    • pp.348-355
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    • 1994
  • Styloid process is a slender pointed bone of variable length, which project downward, forward, and slightly medialward from the posteroinferior portion of the tympanic part of the temporal bone. Embryologically, the styloid process is derived from Reichert's cartilage, a structure of second branchial arch origin. Most patients with elongated styloid process remain asymptomatic, but some patients complain pain and sensation of foreign body in the throat, dysphagia, dysphonia, referred otalgia. Recently, we have experienced a case of elongated styloid process in a fifty-nine year old man. He had been suffered from Rt. side sore throat, headache and pharyngeal discomfort during head movement. Through various X-ray examination, Xeroradiography, and palpation of tonsillar fossa, elongated styloid process on Rt. side was confirmed. Under the general anesthesia, it was successfully removed out via transoral approach technique, described by Eagle. The resected styloid process was 2.5cm in it's length and he was freed from the symptoms without further complication.

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Investigation on the integrated transfer function characteristics for the buffeting response prediction of elongated structures

  • Yi Su;Mingshui Li;Jin Di;Yang Yang;Shaopeng Li
    • Wind and Structures
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    • 제37권6호
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    • pp.399-412
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    • 2023
  • Previous studies have shown that the integrated transfer function (ITF) is independent of turbulence characteristics and can be effectively applied to predict the buffeting response of elongated structures, assuming that the strip hypothesis is valid. However, existing research has not effectively identified the ITF through segment model vibration tests, and the influence of the 3D effect on the accuracy of the strip hypothesis and the characteristics of the ITF in wind tunnel tests has not been quantitatively studied. A segment model vibration measurement device that can change a test model's span-width ratio was designed in this study. An airfoil section and a streamlined box girder section structure were taken as the background, and their ITFs were effectively identified under different L/B (L denotes the turbulent integral scale and B denotes the structural width) and model span-width ratios. The influence laws of the 3D effect on the accuracy of the strip hypothesis and ITF identification in wind tunnel tests were systematically investigated. The results showed that L/B and the structural span-width ratio are two significant controlling factors that affect the accuracy of the strip hypothesis and ITF identification. The research provides an effective experimental method for accurately predicting the buffeting response of elongated structures based on ITFs identified through segment model vibration tests.

Origin of Callus and Vascular Cambium in Debarked Stem of Robinia pseudoacacia

  • Soh, Woong-Young
    • Journal of Plant Biology
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    • 제37권3호
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    • pp.317-323
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    • 1994
  • The calluses formed on the surface of a quarter-girdled Robinia pseudoacacia stems have been shown to originate from immature xylem cells and preexisting cambial cells. The cellus is not only formed by periclinal and anticlinal divisions of radial cells, but also axial cells. In tangential view, the callus at initial stage showed heterogeneous structure composed of long and short cells and then homogeneous one with short cells. Some cells of homogeneous structure in middle region of callus at early stage is later elongated and others mainly divided in trasverse plane. In the result the homogeneous structure becomes into a heterogeneous one. Subsequently, the long cells in heterogeneous structures elongated further and became fusifrom initials, and the short cells divided transversely became ray initials. The appearence of homogeneous and heterogeneous structure in the callus on debarked stem without organ elongation is almost similar to that of the structure in the procambium of young stem which is elongating extensively. Eventually, the ontogeny of vascular cambium in wound callus resembles that of a young stem grown normally, although the debarked stem does not grow in length but in girth and the young stem elongates activity. These findings mean that the active intrusive growth of short procambial cells occurs during the differentiation of fusiform cambial cells.

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유구낭모충에 관한 연구 -유구낭모충의 미세구조- (Studies on the Bladder Worm, Cysticercus cellulosae -The Ulrastructure of C. cellulosae-)

  • 이순형
    • Parasites, Hosts and Diseases
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    • 제21권1호
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    • pp.75-82
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    • 1983
  • An electron microscopic study was performed to know the basic tegumental structure of Cysticercus cellulosae. The scolex and bladder portions of cysticerci (human and porcine strains) were prepared for transmission and scanning electron microscopy by conventional procedures. In general, the tegument of C. cellulosae showed the basic ultrastructure of cestode tegument on electron micrographs. The teguments of both scolex and bladder portions consisted of such components, i.e., an outer vesicular layer with numerous microtriches and inner filroug layer. Below the fibrous layer, there were layers of muscle bundles and tegumental cells. The microtriches which covered the surface of cysticercus revealed two distinctly different shapes. The characteristic bladder-like, elongated pyramid shaped "tetrahedrial form" was observed on the surface of the scolex portion, whereas the elongated cylindrical "filamentous form" was distributed on the stirface of bladder portion. In spite of the difference of isolated host and location, the cysticerci showed tole same result. But dimensional variations of the tegument according to topography of the worm were observed. The possibility of application in making differential diagnosis from other larval cestodes and possible functions of this larval tegument were discussed.

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대두 유식물의 배축에 있어서 유관속형성층의 기원 (Origin of the Vascular Combium in the Developing Hypocotyl of Glycine max Seedling)

  • 강경덕
    • Journal of Plant Biology
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    • 제31권4호
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    • pp.289-298
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    • 1988
  • The pattern of elongation in the developing hypocotyl of Glycine max shows that the elongation generally proceeds from base to the cotyledonary node in acropetal diredtion, although earlier elongation takes place through the entire hypocotyl. Because the differentiation of the vascular cambium in the hypocotyl advances also acropetally, it can be seen that the acropetal wave of hypocotyl elongation is associated with the acropetal differentiation of the cambium in the hypocotyl elongation is associated with the acropetal differentiation of the cambium in the hypocotyl elongation is associated with the acropetal differentiation of the cambium in the hypocotyl. The elongation of procambial cells occurs not only during active elongation but also after cessation of elongation of the hypocotyl. In tangential view, the procambium of the hypocotyl in early stage has homogeneous structure composed of short cells. Subsequently, these procambial cells elongate actively and then become elongated long cells. These long cells eventually become fusiform initials, while some of elongated long cells are transversely divided and then converted into ray initials. The characteristics of the vascular cambium are entirely acquired some time after hypocotyl elongation is completed, and the transitin from procambium to vascular cambium in the hypocotyl is a rather gradual process.

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Carbon Nanotube Gate-Elongated Tunneling Field Transistor(CNT G-E TFET) to Reduce Off-Current

  • 허재;전승배
    • EDISON SW 활용 경진대회 논문집
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    • 제2회(2013년)
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    • pp.240-242
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    • 2013
  • In this paper, novel Carbon Nanotube Gate-Elongated Tunneling Field Transistor(CNT G-E TFET) is proposed. This proposed device is designed to decrease off-current around 2~6 orders of magnitude compared to the gate-channel size matched TFET. Mechanism of CNT G-E TFET creates additional steps in energy band structure so that off-current can be reduced. Since CNT TFETs show a great probability for tunneling processes and they are beneficial for the overall device performance in terms of switching speed and power consumption, CNT G-E TFET looks pretty much promising.

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한국산 미꾸리 Misgumus anguillicaudatus (Pisces, Cobitidae) 피부 구조 및 조직화학적 특징 (Structure and Histochemistry of Skin of Mud Loach, Misgurnus anguillicaudatus (Pisces, Cobitidae), from Korea)

  • 박종영;김익수
    • 한국어류학회지
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    • 제11권2호
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    • pp.109-116
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    • 1999
  • 한국산 미꾸리 Misgurnus anguillicaudatus의 피부 구조 및 조직화학적 특정을 조사하기 위해 등, 측면, 복부, 머리부분의 피부를 조사하였다. 미꾸리의 epidermis는 elongated mucous cell과 club cell의 2개의 gland로 구성되었으며 두께는 아주 두꺼웠다. mucous cell은 acid mucopolysaccharides의 물질을 분비하였으나 club cell은 mucopolysaccharides에 어떠한 반응도 보이지 않았다. 표피의 기저층은 림파구를 가지는 lymphocytic space가 발달하였으며 기저막과 상피세포사이에 배모양의 감각세포인 pit organ이 존재하였다. Dermis의 stratum laxum에는 acid mucopolysaccharides를 나타내는 부분(a definite area)이 존재하며, 이러한 물질은 비늘에도 분포하고 있다. 작은 비늘이 dermis속에 파 묻혀 있으나 머리부분에는 없다. 또한 많은 양의 모세혈관들이 기저막 바로 아래에 존재하였다. 피부의 이러한 특징들은 미꾸리가 공기를 이용하는 피부호흡과 밀접한 관계가 있다.

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한국산 남방짱뚱어 Scartelaos gigas의 후각기관 구조에 관한 연구 (A Study on the Structure of Peripheral Olfactory Organ in the Korean Mudskipper, Scartelaos gigas (Pisces, Gobiidae))

  • 김현태;이용주;박종성;박종영
    • 한국어류학회지
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    • 제26권4호
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    • pp.281-287
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    • 2014
  • 수중과 육상의 이중적인 생활을 하는 남방짱뚱어 Scartelaos gigas (amphibious mudskipper)의 후각기관을 해부학과 조직학적으로 연구하였다. 그 결과 후각기관은 좌우 한 쌍이 존재하며 각 기관은 한 개의 가느다란 긴관 (an elongated canal)과 사비강과 누비강의 두 개의 비강 (ethmoidal and lacrimal nasal sacs)으로 구성되어 있었다. 각 관의 내벽에 발달한 감각 상피는 3~4개의 섬모를 가지는 감각 수용기 세포 (receptor cell), 지지세포 (supporting cell), 기저세포 (basal cell) 그리고 점액세포 (mucus cell)들로 구성되는 다세포성 구조로 이루어져 있었다. 반면에 비감각 상피는 감각기를 갖지 않는 주름진 표면만을 가지고 있었다. 또한 두 개의 비강은 상피 표면에 점액 방울 (mucin droplet)을 가지고 있었다. 따라서 남방짱뚱어의 이러한 후각기관의 특징은 생태적 습성과 서식처에 관련된 반수중 생활 (semi-aquatic life)에 적응한 특징으로 사료된다.