• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2003.11a
• /
• pp.885-891
• /
• 2003

Effects of each acoustic property on absorption characteristics of polyester fiber materials has been studied in this paper. It would be impossible for us to measure effects of each acoustic property by experimental method since we cannot make sound-absorbing materials in which only one of the properties is changed. We have adopted a numerical prediction method to carry out parameter studies for each acoustic property. And to get a general behavior of acoustic performance of the materials, the numerical simulation has been repeated to several cases of different bulk density. Finally we have obtained frequency-dependent control factors in the absorption performance which gives us design capability of acoustic absorbing materials.

• Journal of Chest Surgery
• /
• v.25 no.8
• /
• pp.856-862
• /
• 1992

The author reviewed 50 cases of positive sputum AFB patients following pulmonary resection of pulmonary tuberculosis [total 617 cases] operated on at the National Kongju Hospital during 6 years period, from January, 1985 to December, 1990. 1. There were 36 male and 14 female patients ranging from 20 to 50 years old[mean age, 33.8 years] 2. An average duration of pulmonary tuberculosis history was 7.5 years. 35 cases[76%] had many drug resistance of tuberculosis [above 5 drugs]. 3. The majority indication for pulmonary resection were persistent positive sputum AFB with cavity or destroyed lung or hemoptysis. 23 cases[46%] underwent pneumonectoy and 13 cases[23%] lobectomy. The postoperative complications occured in 19 cases [38%]. 4. 34 cases[68%] occured sputum AFB positive following operation unitil 6 months, and 6 cases[12%] occured 2 years later 5. 21 cases[42%] got conversion to negative sputum, and then 29 cases[58%] remained persistent positive sputum.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.26 no.2
• /
• pp.199-204
• /
• 2017

In this study, analytical methods for designing a torque arm pin and elastomeric bushings of a conventional-type three-point-suspension gearbox of a wind turbine are investigated. The design loads for the torque arm were derived by considering the effects of the transmitted torque and self-weight of the gearbox. Based on the design loads, design methods for the torque arm pin and elastomeric bushings were introduced in the terms of material and size selection. Finally, a small-scale conventional-type gearbox was designed by applying the derived design methods. This study is an elementary and analytical study for the design of the torque arm pin and elastomeric bushings. It is necessary to verify and supplement the results further through extensive experimentation.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
• /
• 2011.10a
• /
• pp.143-149
• /
• 2011

In recent, many forest residues have been generated by the National Forest Management Operation. Unfortunately, most of the forest residues are supposed to be used as raw materials for burning fuels like wood pellets. In this study, we investigated whether or not this forest biomass mixed in various ages and species could be used as raw materials for making kraft pulps in a view of optical properties.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
• /
• 2011.10a
• /
• pp.327-333
• /
• 2011

This study investigated the prime difference between different methods for measuring a sizing degree. Based on the results coming from the study, a new type of the automatic measuring system of a sizing degree. The system includes synchronized devices for measuring contact angle and St$\ddot{o}$ckigt sizing degree at the same time.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
• /
• 2011.10a
• /
• pp.289-296
• /
• 2011

Recently, much of forest biomass has been obtained from the national forest management operation. Unfortunately, Korean Forest Services has a plan to use this forest biomass as energy fuels for wood pellets. Considering unhappy situation that about 80% of wood pulps has been imported, it is regarded as unwise decision. If forest biomass can be used to make pulps or other valuable woody products, we are able to double its economic value than the raw materials for wood pellets. In this study, we explored alternative raw materials for wood biomass used to make wood pellets. For this, fresh technology such as torrefaction was applied with the other lignocellulosic biomass.

• 한국신재생에너지학회:학술대회논문집
• /
• 2008.10a
• /
• pp.153-156
• /
• 2008

MILD combustion has been successfully applied to gaseous fuels and few commercial systems are now in operation. Extending MILD combustion applicability to solid fuel of sawdust is the focus of the present work. The MILD combustion furnace at the University of Adelaide in Australia was used in this study. A measurement of $O_2$ and CO emissions have been carried out in parallel with consideration of NOx emission and compared in each modes of conventional natural gas combustion, natural gas MILD combustion, NOx emission in natural gas MILD combustion mode can be reduced to 20% in comparison with conventional combustion. Emission in cases of air carrying sawdust combustion and $CO_2$ carrying sawdust combustion were also compared. Air and $CO_2$ were sued as a carry gas for the sawdust. It was found that MILD conditions are possible for sawdust particles of less than $355{\mu}m$ without additional air pre-heating. It was also found that when using $CO_2$ as the carry gas the flame inside the furnace was not visible anymore and that NOx emission dropped to less than two folds.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2004.05b
• /
• pp.1107-1111
• /
• 2004

물부족 철상은 심자한 사회적 문제로 대두되고 있으며, 이를 대처하기 위한 방안으로 지표수-지하수 연계 이용에 대한 연구가 진행되고 있다. 지표수와 지하수를 연계이용 하는 방안 중 강변여과수는 강변에 분포되어 있는 충적층에 강물을 통과시켜 취수하는 것으로 수질과 수량을 동시에 해결할 수 있다고 알려져 있다. 최적의 강변여과수 취수지점을 선정하기 위한 첫 단계로 어느 지역이 적합한 지 그 여부를 판단할 필요가 있으며, 경우에 따라서는 복수 지역의 우선 순위를 결정하는 것이 요구될 때도 있다. 본 연구에서는 강변여과수 개발지역 적지분석을 위해 복잡한 의사결정 문제를 계층적으로 나누어 분석하는 기법인 계층분석과정(AHP)을 이용하였고, 분석에 필요한 의사결정인자를 도출하였다. 그리고 각 인자의 상대적 중요도를 정량화 한 후, 이를 바탕으로 강변여과수 개발을 위한 적지를 산정하였다.

• Journal of the Korean Vacuum Society
• /
• v.3 no.3
• /
• pp.341-345
• /
• 1994

As+ 와 P+ 이온들이 주입된 실리콘에서 주입 이온들의 확산 및 실리콘의 재결정화에 열처리가 미치는 영향에 대해서 조사하였다, 여기서 이온 주입량은 실리콘 표면영역을 비정질화하기에 충분한 양 이었다. 이온 주입 시실리콘 내부에 생성된 손상들을 제거하기 위해 온도와 시간을 변화시켜 가며 시편 을 전기로 속에서 열처리하였다. 그러나 이때 야기된 도우펀트들의 과도적인 확산에 의해서 접합깊이는 예측한 것보다 더욱 깊은 곳에서 나타나다. 이러한 과도적인 확산은 주로 이온 주입으로 인해 야기된 시편들이 손상들을 제거하기 위한 열처리 과정동안 일어난 것으로 생각된다. 이것은 SIMS와 SUPREM IV simulation 에 의해서 확인할 수 가 있었다. As+ 와 P+ 이온이 주입된 실리콘의 결정성 회복을 Raman 분광법을 이용하여 조사하였다.

• Journal for History of Mathematics
• /
• v.33 no.3
• /
• pp.167-177
• /
• 2020

Cooperative behavior may seem contrary to the notion of natural selection and adaptation, but is widely observed in nature, from the genetic level to the organism. The origin and persistence of cooperative behavior has long been a mystery to scientists studying evolution and ecology. One of the important research topics in the field of evolutionary ecology and behavioral ecology is to find out why cooperation is maintained over time. In this paper we take a historical overview of mathematical models representing cooperative relationships from the perspective of mathematical biology, which studies population dynamics between interacting biological groups, and analyze the mathematical characteristics and meanings of these cooperative models.