• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제50권8호
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• pp.409-413
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• 2001

In the electron-gun of CRT, the Mo-tip FEA was employed as cold cathode in order to replace the conventional thermal cathode. The Mo-tip FEA was designed and fabricated according to CRT specification and mounted on the electron-gun. It was known that fabricated cold cathode electron-gun showed better performance in terms of maximum emission current and switch-on time when compared with the ones of thermal cathode electron-gun, but some geometrical structures in the inside of electron-gun must be changed to reduce the gate leakage current. Finally, the potential applicability was guaranteed by means of operating the 19 inch-sized LG-color CRT using the fabricated cold cathode electron-gun.

• 한국공작기계학회논문집
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• 제16권4호
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• pp.58-63
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• 2007

A compact gun drill machine was developed to improve productivity and economical efficiency for small and medium enterprise tool makers. Gun drilling works are mainly using at molding, automobile, aircraft industry and special tool makers to make deep holes. As gun drill machines are very expensive and big burden for small tool makers, so that works used to execute through outside orders but it was required lot of cost too. Most of gun drill machines are providing for high volume and large capacity enterprises. In order to use for small and medium enterprises that compact gun drill machine was designed and developed. It could be improved product quality, productivity and manufacturing cost for small and medium enterprises by using this machine.

• 소음진동
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• 제8권1호
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• pp.203-211
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• 1998

In order to find out relationship between hit probability and gun firing of a moving tank, a turret and flexible gun system model has been developed using a recursive flexible multibody dynamics. For a firing simulation model, nodal coordinates for a finite element model of a flexible gun have been employed to include transverse loads to the gun tube due to moving bullet and ballistic pressure. Modal coordinates are also used to represent the motion induced gun vibration before a firing occurs. An efficient switching technique from modal equations to nodal equation has been introduced for an entire gun firing simulation with a rotating turret.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.1023-1027
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• 1996

In this paper, the new technology and R&D status is presented, which accelerates the projectile using the electrical energy to overcome the limit of the conventional gun. The ETC (electro_thermal_chemical) gun, one kind of electric guns, seems to be the highly probable candidate as the next generation gun. The high density power supply and the forming and control of the current pulse are required to develop the ETC gun. And, the interior ballistics considered the mechanism of ETC gun must to be studied.

• 한국군사과학기술학회지
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• 제16권6호
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• pp.752-761
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• 2013

A new gun fire control system has been developed for the Korean next generation frigate class. The engineering requirement was far more tightened than the PKG-A class for the firing range availability and gun control function since 5 inch gun is adopted for the new ship. We mention about the principal technologies required to build a generic gun fire control system and proposed methods for the new gun fire control system. The new system has been designed based on the proposed methods in order to satisfy the requirement and functionality has been proved to be acceptable through the sea trial by Korean navy.

• 농업과학연구
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• 제48권1호
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• pp.103-117
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• 2021

The severe effects of climate change, such as global warming and the El Niño phenomenon, have become more prevalent. In recent years, natural disasters such as drought, heavy rain, and typhoons have taken place, resulting in noticeable damage. Korea is affected by droughts that cause damage to rice fields and crops. Societal interest in droughts is growing, and measures are urgently needed to address their impacts. As the demand for high-quality agricultural products expands, farmers have become more interested in water management, and the demand for field irrigation is increasing. Therefore, we investigated water demand in the irrigation of drought-vulnerable crops. Specifically, we determined the water requirements for crops including cabbage, red pepper, apple, and bean in four regions by calculating the consumptive water use (evapotranspiration), effective rainfall, and irrigation capacity. The total consumptive water use (crop evapotranspiration) estimates for Dangjin-si (cabbage), Yesan-gun (apple), Cheongyang-gun (pepper) in Chungnam, and Goesan-gun (bean) in Chungbuk were 33.5, 206.4, 86.1, and 204.5 mm, respectively. The volumes of groundwater available in the four regions were determined to be the following: Dangjin-si, 4,968,000 m³; Yesan-gun, 4,300,000 m³; Cheongyang-gun, 1,114,000 m³, and Goesan-gun, 3,794,000 m³. The annual amounts available for the representative crops, compared to the amount of evapotranspiration, were 313.9% in Dangjin-si, 29.5% in Yesan-gun, 56.1% in Cheongyang-gun, and 20.1% in Goesan-gun.

• 대한세포병리학회지
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• 제9권1호
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• pp.55-61
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• 1998

To compare the diagnostic yields and complication rates of transthoracic fine needle aspiration cytology(FNAC) and gun biopsy in the diagnosis of pulmonary mass, a retrospective review was performed in 125 cases. Under the fluoroscopic guide, FNAC was performed by 20G Chiba needle in 91 cases, core biopsy was done by 18.5 G vaccum needle attached with automated biopsy gun in 74 cases and both procedures were done together in 37 cases. Overall sensitivity was 88.4% in FNAC and 87.5% in gun biopsy. For malignant pulmonary tumors, correct type correlation with final diagnosis was obtained in 33(76.7%) out of 43 cases by FNAC and 30(75.0%) out of 40 cases by gun biopsy. For benign pulmonary lesions, there were correct type correlation in 14(35.0%) out of 40 cases by FNAC and 14(53.8%) out of 26 cases by gun biopsy. The complication was pneumothorax and hemoptysis. Pneumothorax occured in 11.1% of FNAC, 10.9% of gun biopsy and 10.9% of both technique, among which chest tube drainages were necessary in one patient by gun biopsy and in three patients by both technique. Although no significant difference of diagnositc accuracy and complication rate was found between FNAC and gun biopsy, gun biopsy was more helpful in the diagnosis of pulmonary benign lesions than FNAC.

• 대한기계학회논문집A
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• 제41권9호
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• pp.877-885
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• 2017

본 논문에서는 포신의 강선을 고려한 포 발사 해석기법을 다룬다. 포 발사 환경에서 탄두는 고충격 및 고회전의 동적 거동이 발생한다. 이러한 동적 거동에서 탄두 및 탄두 내 전자 장비가 손상되는 사례가 발생하고 있다. 따라서 포 발사 환경에서 탄두의 동적 거동 분석 및 생존성 평가를 위한 포 발사 해석기법의 개발이 필요한 실정이다. 본 논문에서는 앞서 선행연구자들의 단순화된 포 발사 해석기법을 개선하여, 포신의 강선과 탄대의 접촉에 따른 탄두의 회전을 구현할 수 있는 포 발사 해석기법을 개발하였다. 개발된 포 발사 해석기법은 실험결과와 비교를 통하여 검증하였으며, 제안된 해석기법을 이용하여 포 발사 시 탄두의 동적 거동 및 생존성을 평가하였다.

• Journal of the Korean Wood Science and Technology
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• 제46권5호
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• pp.437-448
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• 2018

본 연구는 태백산맥을 기준으로 영동(고성군), 영서(홍천군), 영남(봉화군) 세 지역 간 소나무의 재질차이의 유무를 알기위해 물리적 특성을 조사하였다. 기건함수율 및 생재함수율(인위적)의 산지 간 차이를 보이지 않았다. 비중은 심재부와 변재부에서 봉화군 소나무가 두 산지보다 높았으며, 고성군과 홍천군 소나무 사이에는 심재부에서는 고성군 소나무가 높고 변재부에서는 홍천군 소나무가 고성군 소나무 보다 높게 나타났다. 심재부의 비중이 높게 나타난 고성군 소나무가 강도적으로 홍천군 소나무보다 클 것으로 판단된다. 수축율은 방사방향의 경우 산지 간 차이가 없고, 접선방향의 경우는 가도관장이 긴 봉화군 소나무가 높게 나타났다. 흡습율은 산지 간 차이가 거의 없는 것으로 나타났다. 이 결과로 소나무를 효율적으로 사용할 수 있고, 육종적으로 좋은 재질의 품종생산에도 도움이 될 것으로 생각한다.

• Journal of Magnetics
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• 제18권4호
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• pp.481-486
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• 2013

An electromagnetic launcher (EML) system accelerates and launches a projectile by converting electric energy into kinetic energy. There are two types of EML systems under development: the rail gun and the coil gun. A railgun comprises a pair of parallel conducting rails, along which a sliding armature is accelerated by the electromagnetic effects of a current that flows down one rail, into the armature and then back along the other rail, but the high mechanical friction between the projectile and the rail can damage the projectile. A coil gun launches the projectile by the attractive magnetic force of the electromagnetic coil. A higher projectile muzzle velocity needs multiple stages of electromagnetic coils, which makes the coil gun EML system longer. As a result, the installation cost of a coil gun EML system is very high due to the large installation site needed for the EML. We present a coil gun EML system that has a new structure and arrangement for multiple electromagnetic coils to reduce the length of the system. A mathematical model of the proposed coil gun EML system is developed in order to calculate the magnetic field and forces, and to simulate the muzzle velocity of a projectile by driving and switching the electric current into multiple stages of electromagnetic coils. Using the proposed design, the length of the coil gun EML system is shortened by 31% compared with a conventional coil gun system while satisfying a target projectile muzzle velocity of over 100 m/s.