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Efficacy of Acid Cleaning on the Deoxidation of Titanium Powder Using Calcium
홍천일,임재원 대한금속·재료학회 2018 대한금속·재료학회지 Vol.56 No.3
The optimum acid cleaning conditions for removing CaO formed by the reaction of Ca with Ti powder were investigated in this study. In this experiment, we used Ti powders composed of irregular polygonal Ti particles with average sizes of 125 mm and 250 μm. Ca granules were charged at 50% of the Ti mass into a deoxidation pot with Ti powder, and then the Ti powder with the Ca granules was deoxidized at 800 °C in a vacuum atmosphere of 5.0 × 10-4 torr. It was confirmed that subsequent acid cleaning with 10% HCl for 5 minutes reduced the initial oxygen concentration of the 125 μm-sized Ti powder from 2,000 ppm to 1,105 ppm. In the case of the non-contact deoxidation using Ca vapor at 900 °C, it was established that the non-contact deoxidation effect was higher than the contact type under the optimum acid cleaning condition of 10% HCl for 5 minutes. XRD and SEM analyses detected some Ca particles, and residual CaO on the Ti powder surface was confirmed without acid cleaning, but the acid cleaning process completely removed the residual CaO. It was also found that the deoxidation and acid cleaning decreased the c/a axial ratio of the Ti powder from 1.5885 to 1.5851.
Pirbuterol 분무흡입제 사용에 의한 기관지 확장효과에 관한 연구
홍천수,이상용 대한천식알레르기학회 1986 천식 및 알레르기 Vol.6 No.2
Pirbuterol [2-hydroxymethyl-3-hydroxy-6-(1- hydroxy-2-tert-butyl-aminoethyl) pyridine, dihydrochloride] is a new agent (Pfizer limited) with similar structure to that of salbutamol, but the benzene ring has been replaced by a pyridine nucleus. The pharmacologic effects of pirbuterol have shown potent, long acting sympathomimetic bronchodilating effects with high selectivity for pulmonary adrenergic receptors as similar as salbutamol, but much less cardiac effects than salbutamol. We evaluated the bronchodilating effects after single inhalation (2 puffs) of pirbuterol inhaler to nonspecific and specific bronchoconstriction patients and outpatient asthmatics, and effects and adverse reactions in asthmatics with long-term usage of pirbuterol inhaler. The results were followings: l. Out of 7 asthmatics, one at 5 min., 3 at 10 min., 2 at 20 min. and 2 at 30 min. after single inhalation noted the maximum increment of peak flow rate (PFR). The bronchodilating effects were persisted in 60 minutes. There were no specific changes of pulse rates and blood pressure initial and during study after inhalation of pirbuterol inhaler in these cases. 2. In methacholine induced bronchoconstriction, the increments of FVC, FEV1 and FEF 25-75% of pirbuterol inhalation group (n=45) were statistically higher than those of saline inhalation group (n=25) (P < 0.001), but less than those of isoproterenol inhalation group (n=33) (P < 0.001). 3. Asthmatics (4 cases) in late bronchoconstriction response of house dust bronchoprovocation test revealed more than 20% increments of FVC, FEV, and FEF25-27 % after inhalation of pirbuterol inhaler than before inhalation. The increments of parameters of pulmonary function tests in pirbuterol inhalation cases were less than those of isoproterenol inhalation cases (5 cases). 4. Nineteen out of 28 asthmatics (67.9%) in outpatient clinic showed more than 10% increments of PFR after single inhalation of pirbuterol inhaler. There was. No case without increment of PFR and no case with decrement. 5. Two out of 50 asthmatics with regular medi- cines and intermittent use of pirbuterol inhaler during acute symptom exacerbation showed mild tolerable adverse reactions immediately after pirbuterol inhalation (one case; mild weakness and palpitation, one case; nervousness). All of them noted effective control of aggravated asthma symptoms after inhalation of pirbuterol inhaler. With above results, pirbuterol inhaler showed effective bronchodilating effect in nonspecific and specific bronchoconstriction states. And we can suggest it will be used safely for symptom relief in acute exacerbated asthmatics with regular medications.
홍천한(Chun Han Hong),김병수(Byoung Soo Kim),박주원(Joo Won Park),제정형(Jung Hyoung Jea),이성근(Soung gyon Lee) 한국항공우주학회 2006 韓國航空宇宙學會誌 Vol.34 No.7
일반적인 항공 촬영용 무인비행선은 GIS 데이터를 획득하기 위하여 기체 조종사와 영상 장치 조종사가 필요하며, 좋은 영상을 위해서는 이들의 호흡과 정확한 위치로의 이동이 중요하다. 본 논문에서는 이런 인력의 소요를 줄이고 정확한 위치/고도의 사전 계획된 비행경로를 자동비행하는 11m급 무인비행선의 고전제어 기반의 자동비행 제어법칙을 소개한다. 또한 이를 검증하기위해 실시한 비행시험의 각 단계별 절차와 유의사항, 외란에 의한 추종 오차를 줄이는 LOS 가이던스 알고리즘을 제시하고 비행시험 결과를 통한 게인 튜닝절차를 소개한다. General unmaned airship, in use of aviation photography, needs both airship-controller and camera-controller who work together in harmony. In oder to reduce this manpower and get the good Geographical Information Systems(GIS) data, it is necessary to use a autopilot controller which guides a exact path lines. This paper presents the autopilot control law base on classical PID control. Moreover, this paper shows the result of flight test, the procedure of gain tuning and LOS guidance algorism that is reduce a tracking error.