日本自動車 部品生業의 發展에 關한 硏究 : 下請 生産制의 定着·發展을 中心으로 Focusing on the Settlement and Development of Subcontractors

鄭炳翼 울산대학교 1996 사회과학논집 Vol.6 No.1

자동차산업의 발전은 부품산업의 발전이 전제가 된다고 할 수 있다. 즉 완성차의 경쟁력은 부품 산업의 발전여하에 달려 있다고 하여도 과언이 아니다. 일본은 구미에 비해 자동차 산업의 후발국임에도 불구하고 비교적 단기간내에 세계 최초의 자동차 생산.수출국으로 발전하게 되었는데 이는 자동차 부품 산업의 발전에 힘입은 바가 크다고 하겠다. 본 논문은 자동차 부품 산업의 하청 생산제의 정착.발전과정을 분석함에 있어 자동차 생산의 성립조건 측면에서 보았을때 자동차 산업의 하청 생산제의 정착.발전 과정을 분석함에 어떠한 문제가 있었고 그 문제가 어떻게 해결되고 거기에 하청 생산제가 어떠한 관련을 하면서 정착.발전하였는가, 도 하청 생산제의 정착. 발전과정에서 하청기업의 전문기술, 경영능력의 축적을 가능하게 한 요인은 무엇인가, 그리고 그것을 달성시킨 모기업과 정부의 역할을 규명하고자 한다. The development of motor parts industry can be prerequisite for the advance of parts industry. It is no exaggeration to say that the competitiveness of mptor finish is totally dependent upon the development of parts insustry. Japan has been one of the world's largerest motor production and export countries. In a short period, the rapid development of Japan's motor parts has greatly contributed to the development of its industry. This study, firstm analyzed the problems inherent in the developmental processes of Japanese motor industry. Then it tries to answer how the problems have been solved in relastion with the motor industry subcontractors. Finally, the study try to find the main factors concerning txchnological advancement of motor subcontractors and government efforts.

MySQL을 연동한 게시판 DB 구축에 관한 연구

현부금,조준익 군산대학교 정보통신기술연구소 2000 情報通信技術硏究論文集 Vol.4 No.-

In these days, we can get much information by using the Internet as the computers are supplied. The freeboard gives an information in the web sites or homepages specifically. In this paper, we want to operate the freeboard with the MyQSL. In addition, we proposed that the MyQSL gives the capability to search, upload and correct data as well as to ask a question and give an answer from the free board.

펨토초 레이저에 의한 SUS 가공 특성 및 리플 생성

손익부,고명진,김영섭,노영철 한국레이저가공학회 2009 한국레이저가공학회지 Vol.12 No.1

Ripple formation of femtosecond laser in stainless steel is investigated using 184 fs pulses with a center wavelength of 785 nm. The effect of the laser polarization relative to the translation direction is observed. For drilling with a certain aspect ratio, reflections at the hole walls take place, leading to a non-uniform intensity distribution deep inside the formed hole. Finally, it is shown that a circular polarization during the drilling process significantly improves the quality of the produced holes.

Microstructuring of Optical Fibers Using a Femtosecond Laser

Ik-Bu Sohn,Youngseop Kim,Young-Chul Noh,Jin-Chang Ryu,김진태 한국광학회 2009 Current Optics and Photonics Vol.13 No.1

Laser ablation with femtosecond lasers is highly promising for microfabrication of materials. Also, the high peak power of femtosecond lasers could induce a multiphoton absorption to ablate transparent materials. Similar results have also been were obtained in the case of optical fibers. In this paper, we present our experimental results of femtosecond laser microstructuring of optical fiber and its applications to microelectronic components and fiber optic devices. Finally, we directly produced micro holes with femtosecond laser pulses in a single step by moving an optical fiber in a preprogrammed structure. When water was introduced into a hole drilled from the bottom surface of the optical fiber, the effects of blocking and redeposition of ablated material were greatly reduced and the aspect ratio of the depth of the hole was increased. We have presented circular and rectangular-shaped holes in optical fiber.

Formation of a Plano-convex Micro-lens Array in Fused Silica Glass by Using a CO2 Laser-assisted Reshaping Technique

Ik-Bu Sohn,Dongyoon Yoo,Young-Chul Noh,Jae-Hee Sung,Seong-Ku Lee,최훈국,Md. Shamim Ahsan 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.69 No.3

We report on fabricating high-fill-factor plano-convex spherical and square micro-lens arrays on fused silica glass surface by using a CO2 laser-assisted reshaping technique. Initially, periodic micro-pillars are encoded on glass surfaces by means of a femtosecond laser beam, afterwards, the micro-pillars are polished several times by irradiating a CO2 laser beam on top of the micro-pillars. Consequently, a spherical micro-lens array with micro-lens size of 50 μm × 50 μm and a square micro-lens array with micro-lens size of 100 μm × 100 μm are formed on the surface of the fused silica glass. We also study the intensity distribution of light passing through the glass sample engraved with a spherical micro-lens array. The simulation result shows that the focal length of the spherical micro-lens array is 35 μm. Furthermore, we investigate the optical properties of glass samples with engraved micro-lens arrays. The proposed CO2-laser-based reshaping technique is simple and fast and shows promises for fabricating arrays of smooth micro-lenses in various transparent materials.

Direct Writing of a 1-to-4 Optical Splitter and Packaging Technology Using a Femtosecond Laser

Ik-Bu Sohn Sohn,Hyoung-Jong Lee,Hyoung-Ju Park,이만섭 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.4

A 1-to-N optical splitter was fabricated using a focused 785-nm femtosecond laser to directly write a series of 1-to-2 Y-junction splitters in fused silica. The femtosecond laser direct writing technique has the potential to generate not only channel waveguide, but also three-dimensional optical devices. In this paper, a 1-to-4 optical splitter and U-grooves, which are used for fiber alignment, are simultaneously fabricated in fused silica glass by using near-IR femtosecond laser pulses. The obtained splitter was characterized in terms of its optical properties at a wavelength of 1550 nm. The fiber-aligned optical splitter has a low insertion loss, less than 9 dB, including an intrinsic splitting loss of 6 dB and an excess loss due to passive alignment of a single-mode fiber. A 1-to-N optical splitter was fabricated using a focused 785-nm femtosecond laser to directly write a series of 1-to-2 Y-junction splitters in fused silica. The femtosecond laser direct writing technique has the potential to generate not only channel waveguide, but also three-dimensional optical devices. In this paper, a 1-to-4 optical splitter and U-grooves, which are used for fiber alignment, are simultaneously fabricated in fused silica glass by using near-IR femtosecond laser pulses. The obtained splitter was characterized in terms of its optical properties at a wavelength of 1550 nm. The fiber-aligned optical splitter has a low insertion loss, less than 9 dB, including an intrinsic splitting loss of 6 dB and an excess loss due to passive alignment of a single-mode fiber.

Femtosecond laser application to optical memory and microfluidics

Ik-Bu Sohn,Man-Seop Lee,Jeong-Sik Woo,Sang-Man Lee,Jeong-Yong Chung 한국광학회 2005 Current Optics and Photonics Vol.9 No.3

We present a novel method for three-dimensional optical memory and microchannel embedded in fused silica glass. Three-dimensional dot patterning with a femtosecond laser pulse and observation with optical microscope are performed. Dot patterns are created by use of a 0.42 N.A. objective to focus 100 fs laser pulses inside the material. We demonstrate data storage with 2 μm dot pitch and 7 μm layer spacing (36 Gbit/cm3). A three-dimensional microchannel acting as microfluidic and microoptical components is directly fabricated inside a silica glass. The optical micrographs of the microchannel are obtained by a digital camera of a microscope.

Femtosecond Laser Application to PLC Optical Devices and Packaging

Ik-Bu Sohn,이만섭,Sang-Man Lee 한국전자통신연구원 2005 ETRI Journal Vol.27 No.4

Using tightly focused femtosecond laser pulses, we produce an optical waveguide and devices in transparent materials. This technique has the potential to generate not only channel waveguides, but also three-dimensional optical devices. In this paper, an optical splitter and U-grooves, which are used for fiber alignment, are simultaneously fabricated in a fused silica glass using near-IR femtosecond laser pulses. The fiber- aligned optical splitter has a low insertion loss, less than 4 dB, including an intrinsic splitting loss of 3 dB and excess loss due to the passive alignment of a single-mode fiber. Finally, we present an output field pattern, demonstrating that the splitting ratio of the optical splitter becomes approximately 1:1.

Femtosecond micromachining applications for optical devices

Ik-Bu Sohn,Man-Seop Lee,Jeong-Sik Woo 한국광학회 2004 Current Optics and Photonics Vol.8 No.3

Ablation of Polypropylene for Breathable Packaging Films

Ik-Bu Sohn,Young-Chul Noh,Sung-Chul Choi,Do-Kyeong Ko,Jongmin Lee,Young-Jin Choi 한국레이저가공학회 2006 한국레이저가공학회지 Vol.9 No.3

  A Polypropylene (PP) film was ablated using a femtosecond laser with a center wavelength of 785 ㎚, a pulse width of 184 fs and a repetition rate of 1 ㎑. Increments of both pulse energy and the shot number of pulses lead to co-occurrence of photochemical and thermal effect, demonstrated by the spatial expansion of rim on the surface of PP. The shapes of the laser-ablated PP films were imaged by a scanning electron microscope (SEM) and measured a 3D optical measurement system (NanoFocus). And, the oxygen transmission rate (ORT) of periodically laser-ablated PP film were characterized by oxygen permeability tester for modified atmosphere packaging (MAP) of fresh fruit and vegetable. Our results demonstrate that femtosecond pulsed laser is efficient tools for breathable packaging films in modifying the flow of air and gas into and out of a fresh produce container, where the micropatterns are specifically tailored in size, location and number which are easily controlled by laser pulse energy and pulse patterning system.