• 제목/요약/키워드: cone-shaped

검색결과 187건 처리시간 0.026초

3축 열선 PROBE의 특성과 그 평가 (The Characteristics of Triple Hot-Wire Probe and It's Evaluation)

  • 김경훈
    • 한국정밀공학회지
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    • 제5권3호
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    • pp.48-62
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    • 1988
  • A triple hot-wire probe has an essential potentiality for the measure- ment of an instantaneous velocity vector in a three dimensional unsteady flow with large amplitude of velocity fluctuations, the key problems asso- ciated with this instrument are the directional range of applicability and the accuracy. This present paper is concerned with a new method of the techniques of calibration and data processing to estimate the three dimensional flow field using an arbitrary shaped triple hot-wire probe. The method is not based on the assumptions of orthogonality or symmetry and it is especially useful for applications to a hand-made probe where probe geometry is not accurately known. The test application is made to evaluate the effect of cone angles of symmetric non-orthogonal probe.

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페룰 동축연삭시 척킹 오차 해석 (A study on the chucking alignment error analysis in coaxial grinding of ferrule)

  • 김동길;김영태;이상조
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2002년도 춘계학술대회 논문집
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    • pp.9-14
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    • 2002
  • Ferrule is widely used as fiber optic connecters. In fiber-optic communications, the shape accuracy such as coaxiality and cylindricity of ferrule affects insertion loss. When coaxial grinding of ferrule supported by two pin, pin alignment and chucking accuracy are very important. In this research, the kinematic behavior of the ferrule center is investigated in the case where cone-shaped center pins and round circle hales which make contact with each other near the edge of the holes, using homeogenous coordinate transformation and numerical analysis. The obtained results are as follows: The alignment errors between center pins alone do not affect the rotation accuracy of ferrule. The alignment errors between center holes cause a sinusoidal displacement of ferrule. And the maximum displacement of ferrule centers increase in proportion to the center pin angle in the case of a fixed alignment errors

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연질재료의 마이크로 구형렌즈금형 가공특성에 관한 연구 (A Study on the Manufacturing Characteristics for Micro Spherical Lens Mold of Soft Materials)

  • 홍성민;이동주;제태진;최두선;이응숙
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2004년도 추계학술대회 논문집
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    • pp.1466-1469
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    • 2004
  • Micro spherical lens mold processing method based on mechanical one completes a spherical shape by setting a diamond tool of hundreds $\mu$m radius on spins with high speed and then using Z-axis vertical feeding motion like the fabrication of micro drilling. In this method, we can see unprocessed parts shaped like cylinder and cone and check increasing chatter marks and burrs by setting errors of the central axis of rotation on the edge of the tool. That is why this method doesn't suit for the optical lens mold. In this paper presents unprocessed parts are disappeared and chatter marks and burrs are decreased from centre of the lens after using Run-out measuring and setting system on run-out occurred from setting tool. Also the fabrication characteristics of 6:4 Brass, A1601, PMMA are compared and analyzed, establishing the optimum machining condition on each material.

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키아리기형 (Chiari Malformation)

  • 한정훈
    • 보험의학회지
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    • 제27권1호
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    • pp.37-38
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    • 2008
  • The concept of Chiari malformations emerged toward the end of $19^{th}$ century from Chiari's initial descriptions of "alterations in the cerebellum resulting from cerebral hydrocephalus." In 1891, Hans Chiari(1851-1916) suggested cerebellar ectopia in which he classified Type I as "elongation of the tonsils and medial parts of the inferior lobes of the cerebellum into cone-shaped projections, which accompany the medulla oblongata into the spinal canal. The incidence of Chiari malformation has been found to be between 0.56% and 0.77% on MR imaging studies, as well as 0.62% in brain dissection studies. the definition of the adult Chiari malformation has varied with the evolution of neurodiagnositic capabilities and knowledge of physiopathology. This disorder can be associated with significant symptomatology, risk of secondary injury due to trauma, and the risk of progression and damage of the spinal cord due to associated Syringomyelia. Syringomyelia is found in 50 to 70% of Chiari I malformation. It is the clinical judgment of the physicians evaluating this disorder that is of the importance to avoid the therapeutic extremes of pursuing unnecessary surgery or withholding necessary treatment from patients.

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Conventional Female Donor Costume of Cave 79 of Kumtura

  • Shenya, Shenyan
    • The International Journal of Costume Culture
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    • 제12권2호
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    • pp.210-214
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    • 2009
  • Cave 79 of Kumtura grottoes, is the best preserved cave, which has an important meaning for research on Uighur costume. This paper is intended to analyze the costume characteristics of female donors in Cave 79 by comparing image materials between Dunhuang murals and other murals in Xinjiang province. In Cave 79, female donor wears red robe with tight sleeve, whose collar is crescent-shaped decorated. Two different opinions are upheld for this decoration. One regards this as the turn-down collar, while the other believes this as decoration on V-neckline. Red robe is quite common in female donors of Xinjiang and Dunhuang murals and a female in fresco is wearing a crown in a triangle red headwear style, regarded as red silk and drooping at head. Female donors wear an extra coat, kame hair clasp, red jacket, light-colored high-waist skirt with a long-tail waistband, and tangerine Pibo (silk ribbon) with scattered small flowers. All these costume styles are commonly-used by Han females. The kame headwear is also the common ornament for Han females and the female's hairstyle is in cone shape on head by a white kame. Current costumes are similar but not completely same.

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쿠차(龜玆)의 복식 (The Costume of Kucha)

  • 김용문
    • 복식
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    • 제24권
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    • pp.83-101
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    • 1995
  • The purpose of this study is to investigate relation between kucha and Korea by comparing costume. The results are as follows. First, During 508th century, wall paintings of Kizil and Kuizilkargha showed traditional costume such as cutting hair , lapel coller and fitting sleeve coat, pants, boots , belts and knife. Kumtura were also in 6 th, but under the influence of China and Hoehol (회골) after 7th. Second, Men and women cutting hair except king, they put on cone shaped hat and Kun (건), clothing were made of felt and kun(면). Third, it was influenced by Iran that cutting hair in Silla (신라) and Kucha. In Silla , round neckline and V neckline were existed except lapel collar. Jeweled knife of Silla and Kuncha , pattern of Kumdonglee(금동복) showed cultural exchange of centural Asia and Korea along the Silk Rood. It is conscious that Silla preferred centural asia of texture and jewels by prohibition of costume.

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페룰 동축 연삭시 척킹 시스템에 관한 연구 (A study on the chucking system in coaxial grinding of ferrule)

  • 김동길;이상조;안건준;곽철훈
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2003년도 춘계학술대회
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    • pp.987-991
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    • 2003
  • Ferrule is widely used as fiber optic connecters. In fiber-optic communications, the shape accuracy such as coaxiality and cylindricity of ferrule affects insertion loss. When coaxial grinding of ferrule supported by two pin, pin alignment and chucking accuracy are very important. In this research, the kinematic behavior of the ferrule center is investigated in the case where cone-shaped center pins and round circle holes which make contact with each other near the edge of the holes, using homeogenous coordinate transformation and numerical analysis. The obtained results are as follows: The alignment errors between center holes cause a sinusoidal displacement of ferrule. And the maximum displacement of ferrule centers increase in proportion to the center pin angle. The relationship between center pins displacement in coaxial grinding and grinding accuracy was explained.

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A Study on Design and Fabrication of Complex Type EM Wave Absorber with Super Wide-band Characteristics

  • Kim Dae-Hun;Kim Dong-Il;Choi Chang-Mook;Son Jun-Young
    • 한국항해항만학회지
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    • 제30권2호
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    • pp.161-166
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    • 2006
  • In order to construct an Anechoic Chamber satisfying international standards for EMI testing, it has been recognized that the absorption characteristics of the EM wave absorber must be higher than 20 dB over the frequency band from 30 MHz to 18 GHz. In this paper, an EM wave absorber with super wide-band frequency characteristics was proposed and designed in order to satisfy the above requirements by using the Equivalent Material Constant Method(EMCM) and Finite Difference Time Domain(FDTD). The proposed absorber is to attach a pyramidal absorber onto a hemisphere-type absorber on a cutting cone-shaped ferrite. As a result, the proposed absorber has absorption characteristics higher than 20 dB over the frequency band from 30 MHz to more than 20 GHz.

Formation of Mo-Silicide on Mo Tip

  • Oh, Chang-Woo;Kim, Yoo-Jong;Lee, Jong-Duk;Park, Byung-Gook
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2000년도 제1회 학술대회 논문집
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    • pp.217-218
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    • 2000
  • This paper describes a formation of the Mo-silicide on Mo tip to compare the emission characteristics of the Mo tip. Cone-shaped Mo tip arrays were fabricated and silicidized by evaporating a 15nm-thick a-Si film on Mo tip arrays and annealing it in inert ambient at the temperature of $1000\;^{\circ}C$ for 60 sec. The $Mo_5Si_3$ phase of Mo-silicide was observed through X-ray diffraction (XRD) analysis. Although the gate voltage of the Mo-silicide tip increased by 38 V to obtain the current level of 20 nA/tip, the dependence of emission current on vacuum level was improved.

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A study on the Interfacial Properties of Electrodeposited Single Carbon Fiber/Epoxy Composites Using Tensile and Compressive Fragmentation Tests

  • Park, Joung-Man;Kim, Jin-Won
    • Macromolecular Research
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    • 제10권1호
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    • pp.24-33
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    • 2002
  • Interfacial and microfailure properties of carbon fiber/epoxy composites were evaluated using both tensile fragmentation and compressive Broutman tests. A monomeric and two polymeric coupling agents were applied via the electrodeposition (ED) and the dipping applications. A monomeric and a polymeric coupling agent showed significant and comparable improvements in interfacial shear strength (IFSS) compared to the untreated case under both tensile and compressive tests. Typical microfailure modes including cone-shaped fiber break, matrix cracking, and partial interlayer failure were observed under tension, whereas the diagonal slipped failure at both ends of the fractured fiber appeared under compression. Adsorption and shear displacement mechanisms at the interface were described in terms of electrical attraction and primary and secondary bonding forces.