• 제목/요약/키워드: Roller Coverage

검색결과 4건 처리시간 0.021초

기계부품용 금속구 제조공정의 성형롤러 개발에 관한 연구 (A Study on Development of Forming Roller for Metal Ball Manufacturing Process for Machine Parts)

  • 조호성;박치근;박종순;김영호;박철우
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2005년도 춘계학술대회 논문집
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    • pp.1686-1690
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    • 2005
  • Although metal ball can be used as parts of bearing or metal filter, that is used by single product with solder ball or shot ball. Also, according as demand of metal ball of various diameter increase, processing property 솜 extension of coverage are important. Especially an optimal design of cutting roller was investigated for determining appropriate dimensions of components of manufacturing system. In this study, the effects of the diameter and the round radius of cutting roller were calculated and analyzed. We applied data of rigid-plastic FEM Simulation in basis design of equipment to solve these issues, and confirmed processing factor about metal ball manufacturing process that use cutting process of metal wire in this research

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다짐밀도의 이론적 전개 (Theoretical Development of Compaction Density)

  • 허정도;김한용;남영국
    • 한국도로학회논문집
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    • 제2권1호
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    • pp.147-156
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    • 2000
  • 다짐은 포장 공용성에 중요한 영향을 미친다고 알려져 있다. 따라서 이 다짐공정을 포장의 소성변형과 근본적으로 동일하다고 가정하여, 다짐밀도를 롤러다짐수의 항으로 표현하는 이론 모델링식을 정립하였다. 정립된 식의 우수한 데이터 예측능력은 유도과정에 세운 가정들의 검증과 더불어 이 식의 사용 정당화에 대해 확신시켜준다. 유도된 식에 의하면, 대수 밀도 차를 대수 다짐회수의 항으로 그림을 그리면 일차함수의 직선관계식이 주어진다. 그러나 이 직선관계는 공기온도에 의한 냉각과 진동롤러의 진폭과 주기 등의 효과가 존재하면 더 이상 성립되지 않음이 판명된다. 본 연구에서는 이러한 세 요인들에 대한 영향도 함께 연구하여 더 전반적이고 성공가능성을 보여주는 새로운 다짐밀도 식을 제안하였다. 이 제안식을 응용하여 특정다짐공정에 요하는 전체 롤러다짐회수와 최종다짐밀도를 구하는 관계식을 다짐 연구 중 최초로 제시하였다.

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외상성 기관식도루 -수술체험 1례- (A Case Report of Traumatic Tracheoesophageal Fistula)

  • 최승호
    • Journal of Chest Surgery
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    • 제27권10호
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    • pp.888-892
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    • 1994
  • Acquired, traumatic tracheoesophageal fistula [TEF] is rare and difficult problem to manage. This 55 years old man met with a roller accident of a tractor. During accident, he received a penetrating injury on the left upper sternal border. At local clinic, he received closed thoracotomy drainage [CTD]for relief of pneumothorax[left]. Three days after CTD, he complained abdominal pain and hematemesis. The endoscopy revealed large ulcer at the stomach, so he received subtotal gastrectomy. On 10th day post subtotal gastrectomy, he developed aspiration and coughing from a TEF. The esophagogram showed large TEF at the mid-trachea level. So he transfered to our hospital for operation. This patient was operated on for late TEF three weeks after injury. We have used absorble 4-0 Vicryl sutures to repair trachea. We repair all esophageal injuries with two layers of nonabsorbable silk suture. Where suture line on the esophagus, the strap muscle was interposed for reinforcement. And for feeding, the feeding jejunostomy was performed. Postoperatively the osteomyelitis of the manubrium site was developed, so on the 30th postoperative day, an ostectomy of manubrium, both clavicle and fight 1st, 2nd ribs, and the pectoralis major musculo-cutaneous flap coverage were performed.

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Effects of Sequential Trinexapac-Ethyl Applications and Traffic on Growth of Perennial Ryegrass (Lolium perenne L.)

  • Amiri-Khah, Rahim;Eetemadi, Nematollah;Nikbakht, Ali;Pessarakli, Mohammad
    • 원예과학기술지
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    • 제33권3호
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    • pp.340-348
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    • 2015
  • Mowing turfgrasses, especially fast growing species like perennial ryegrass, is one of the most time and money consuming tasks of their management. Trinexapac-ethyl (TE) is a popular plant growth regulator used to reduce mowing requirements, improve stress tolerance, and enhance turf quality. This study was conducted to investigate the effect of TE rate and frequency of applications on growth response and traffic tolerance of perennial ryegrass. The experiment was a split-plot laid out in a randomized complete block (RCB) design with three replications. TE was applied to main plots at 0.00, 0.25, and $0.50kg\;a.i.\;ha^{-1}$. Application pattern included an initial application, followed by two sequential applications at 6-wk intervals. Traffic treatment was applied to subplots with a cleated roller. Results demonstrated that TE consistently reduced vertical shoot growth, clippings dry weight, with maximum growth reduction of 59% and 65%, for 0.25 and $0.50kg\;a.i.\;ha^{-1}$, respectively, occurring at 2 weeks after initial TE treatment (WAT). Traffic also dramatically reduced vertical shoot growth and clippings dry weight. Overall, quality of perennial ryegrass was enhanced by sequential TE applications, however, turf quality and surface coverage reduced greatly under traffic, regardless of TE treatment. Total chlorophyll, chlorophyll a and chlorophyll b and total carbohydrates (TC) contents were also positively influenced following sequential TE application. Our results indicated that TE reduces mowing frequency and enhances turf quality rather than influencing traffic resistance.