• Title/Summary/Keyword: Air gun

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Unrecorded Fungal Species Isolated from Indoor Air in the Log Bed- and Sawdust Media-based Mushroom Cultivation Houses (원목 및 톱밥배지 버섯 재배사 내 실내 공기서 분리한 미기록 진균 보고)

  • Ahn, Geum Ran;Kim, Ji Eun;Kim, Jun Young;Kim, Seong Hwan
    • The Korean Journal of Mycology
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    • v.46 no.4
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    • pp.495-503
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    • 2018
  • Oak mushroom is cultivated using logs and sawdust media as substrates. In this study, fungi were isolated during a monitoring of indoor air in the oak mushroom cultivation houses located in Cheongyang-gun of Chungnam, Geoje-gun of Gyeongnam, Gumi-si of Gyeongbuk, Jangheung-gun of Jeonnam and Yeoju-si of Gyeongggi-do. Identification of the fungi based on morphology and molecular analysis of the internal transcribed spacer region and 28S rDNA, translation elongation factor translation elongation factor 1 a gene, and ${\beta}-tubulin$ gene revealed that six fungi, Cenangium acuum, Neopestalotiopsis surinamensis, Metarhizium marquandii, Periconia macrospinosa, Trichoderma petersenii, and Trichoderma paratroviride that have not been recorded previously in Korea.

The study of force control by using feedback current and encoder signal of the servo-motor on the servo-gun system (서보 모터의 피드백 전류와 위치신호를 이용한 서보건의 가압력 제어에 관한 연구)

  • Lee, Jong-Gu;Kim, Tae-Hyeong;Lee, Se-Heon
    • Proceedings of the KWS Conference
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    • 2005.06a
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    • pp.63-65
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    • 2005
  • Because of simple principal and low cost, resistance spot welding has been used a lot for joining the sheet metal in automotive manufacturing process. Welding current, welding time, and force are the most important variables in resistance spot wording. Air guns have hem still used widely. The requirement of synchronizing between robot and weld-gun has become bigger as the field has been automated. The number of servo-gun in the field is trending upward because there're advantages as like to synchronize with robot and to control the stroke path and force by programming on servo-gun system. But no cleared force control method is suggested on servo-gun system until now. In this study, we proved the feedback current of the servo-motor can be used to an excellent force measuring sensor and the force is controlled by the feedback current. And we also detected force lowering during welding cycle on the servo-gun system and solved by compensated force control.

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The Evaluation on Welding Qualities by Gun Press Force Patterns in the RSW (Resistance Spot Welding) Process using Servo Gun (서보건을 이용한 저항 점용접 공정에서의 가압력 패턴에 의한 용접품질 평가)

  • 박영제;조형석;박지환
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.252-252
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    • 2000
  • The Resistance Spot Welding (RSW) has been considered as an inherently safe and reliable method far joining metals, and has been widely employed, especially in automobile body assembly shops, as a manufacturing process. In recent years, the requirement for more sophisticated quality control procedures has considerably grown in the mass production industries. The object of the application of servo control to spot welding gun is the improvement of quality control in the spot welding, one of conventional industrial areas. The important factors affecting welding qualities (shear strength, nuggest size, indentation depth) are welding current, welding time, and gun press force. Welding current and welding time are controlled by welding timer. But, the conventional welding guns using compressed air are out of control in changing gun press forces in welding process. In this paper, a servo gun welding system having a AC servo motor and a PC control system is presented. The main object of this paper is to estimate the influence of gun press force changes in the welding process (press time -> welding time -> hold time) to welding qualities, and to evaluate welding qualities in real time, by recognizing the patterns of gun press forces changed in the welding process and comparing with the standard patterns.

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Spinning Force and Nutation acting on the Projectile of the Coil Gun (Coil Gun에서 Projectile 에 작용하는 Spinning Force와 Nutation)

  • Kim, Ki-Bong
    • Proceedings of the KIEE Conference
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    • 1994.07a
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    • pp.125-128
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    • 1994
  • One of the abnormal motions of the projectile in the coil gun is spinning. It is found that the spinning force is closely related with air gap distance. Modified and detail analysis for the spinning is suggested in this paper. Two reasons for spinning force and Lorentz force affecting on the spinning are introduced. Nutation, which is a result of spinning, is explained there after.

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A Simulation Model for Performance Evaluation of Air Defense-gun System (대공무기체계의 능력평가를 위한 시뮬레이션모델의 연구)

  • 황흥석
    • Journal of the Korea Society for Simulation
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    • v.9 no.4
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    • pp.77-85
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    • 2000
  • The object of this paper is developing of a simulation model for performance evaluation of ai defense-gun system. We developed a three-step kill probability of areal target in case of one gun on one target considering : 1) estimating the target and warhead intercept point, 2) target vulnerability and 3) computing the kill probability. We used a Monte Carlo simulation method. This model can be used for probabilistic analysis giving results of sufficient accuracy with minimum requirement of input data. Also we developed a computer program according proposed algorithm and a set of experimental results using the proposed method are shown.

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Development of a new test facility for the study of pressure transients in tunnel and micro-pressure waves radiated from the tunnel exit on the railroad (철도터널내 압력변동 및 터널 미기압파 저감 시험장치개발에 관한 연구)

  • Kim, Dong-Hyeon;Oh, Il-Geun
    • Proceedings of the KSME Conference
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    • 2000.04b
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    • pp.611-618
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    • 2000
  • The test facility of the 1/60-scale models for the train-tunnel interactions was recently developed to investigate the effects of entry portal shapes, hood shapes and air-shafts for reducing the micro-pressure waves radiating to the surroundings of the tunnel exits by KRRI in Korea. The launching system of train model was chosen as air-gun type. In present test rig, after train model is launched, the blast wave by the driver did not enter to inside of the tunnel model. The train model is guided on the one-wire system from air-gun driver to the brake parts of test facility end. Some cases of the experiments were compared with numerical simulations to prove the test facility.

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Development of A New Facility for Moving Model Test (한국형 터널 미기압파 저감 시험기 개발)

  • 김동현;양신추;오일근
    • Proceedings of the KSR Conference
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    • 1999.11a
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    • pp.146-154
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    • 1999
  • The test facility of the 1/60-scale models for the train-tunnel interactions was recently developed to investigate the effects of entry portal shapes, flood shapes and air-shafts for reducing the micro-pressure waves radiating to the surroundings of the tunnel exits by KRRI in Korea. The launching system of train model was chosen as air-gun type. In present test rig, after train model is launched, the blast wave by the driver did not enter to inside of the tunnel model. The train model is guided on the one-wire system from air-gun driver to the brake parts of test facility end. Some cases of the experiments were compared with numerical simulations to prove the test facility.

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The Research of Naval Tracking Filter using IMM3 for Naval Gun Ballistic Computer Unit (IMM3를 이용한 사격제원계산장치 대함필터 연구)

  • Lee, Young-Ju
    • Journal of the Korea Institute of Military Science and Technology
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    • v.8 no.3 s.22
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    • pp.24-32
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    • 2005
  • This paper describes the tracking filter performance for Naval Gun Ballistic Computation Unit(BCU). BCU needs tracing filter for gun firing. Using data of tracking sensor, BCU calculates the future position of Target and Gun order in the time of flight. In this paper, tracing filter is designed with interacting multiple model(IMM). The tracking algorithm based on the IMM requirers a considerable number of sub-model for the various maneuvering target in order to have a good performance. But, in the case of ship target, the maneuvering is restricted compared with the air target. Considering the maneuvering properties and adjusting the mode transition probabilities and the process noise of sub-model, We designed the IMM3 algorithm for Naval tracking filter with three sub-model.

The research on CFD turbulance models for comparison according to my secondary air injection into the combustion (연소로 내 2차 공기 분사에 따른 CFD 난류 모델 비교에 관한 연구)

  • Choi, Junhyuk;Choi, Chong-gun;Hwang, Seung-Sik;Shin, Donghoon;Chung, Tae-Yong
    • 한국연소학회:학술대회논문집
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    • 2012.11a
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    • pp.345-347
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    • 2012
  • The secondary air injection influences the flow of the combustion gas in the furnace. Therefore, the analysis of the furnace should be careful in the selection of the turbulent model with CFD. In this study, CFD results of several turbulent models were compared with experimental results. Analysis results suggest to select turbulent models in the furnace secondary air nozzle.

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