• 제목/요약/키워드: Formation loss

검색결과 1,040건 처리시간 0.031초

전자에너지 손실분광 분석법을 이용한 광물에서의 정량적 철 산화수 측정과 분석 (Electron Energy Loss Spectroscopy (EELS) Application to Mineral Formation)

  • 양기호;김진욱
    • 한국광물학회지
    • /
    • 제29권2호
    • /
    • pp.73-78
    • /
    • 2016
  • 점토 광물의 구조 내에 들어 있는 철의 산화수는 퇴적환경의 산화/환원 조건에 대한 정보를 제공하여 준다. 이러한 광물형성의 메커니즘을 밝히기 위해서는 고해상도를 가진 전자현미경을 이용한 나노 스케일 분석이 불가피하다. 투과전자현미경에 장착되어있는 전자에너지 손실분광 분석법(EELS)을 이용하여 정량적 철 산화수 분석을 논트로나이트 점토광물 구조 내 철의 환원으로 인한 K-논트로나이트의 형성의 예를 들어 설명하고자 한다. 철 산화/환원의 정량적 분석을 통하여 퇴적물의 위치에 따른 철 산화도 측정은 광물변화에 대한 연구를 용이하게 해준다. 따라서 본 논문은 전자에너지 손실분광의 분석방법 및 장점을 소개함을 목적으로 한다.

폴리프로필렌의 금속첨가형 난연제에 의한 난연 특성 (Incombustibility of Polypropylene by Metal Addition Flame Retardant)

  • 이상은;송영호;정국삼
    • 한국안전학회지
    • /
    • 제20권4호
    • /
    • pp.40-45
    • /
    • 2005
  • The principal actions of a flame retardant are to decrease or prevent the formation of volatile products and increase the formation of char layer. Use of flame retardant additives can decrease the overall fire hazard of the product containing them thus leading to an increase in overall fire safety. Although several flame retardants have been developed for use in polymers, many of these are known to increase the amount of smoke and toxic gases generated by them. This paper present a new flame retardant using metal addition flame retardant. For this study, the experiments of flame retardancy conducted are as follows : burning ratio, weight loss rate using TGA-DTA, the measurement of LOI and char yield. And smoke mass concentration and CO yield were measured. The metal addition flame retardant reduced burning ratio and weight loss rate, increased the LOI and yield of char formation with decreased smoke mass concentration and CO yield.

Polymer Supported Cyanide as an Efficient Catalyst in Benzoin Condensation: An Efficient Route to α-Hydroxy Carbonyl Compounds

  • Kiasat, Ali Reza;Badri, Rashid;Sayyahi, Soheil
    • Bulletin of the Korean Chemical Society
    • /
    • 제30권5호
    • /
    • pp.1164-1166
    • /
    • 2009
  • Aromatic aldehydes are efficiently self-condensed into $\alpha$-hydroxy carbonyl compounds by polystyrene-supported ammonium cyanide as an excellent organocatalyst in C-C bond formation. The reaction proceeds in water under mild reaction conditions. The polymeric catalyst can be easily separated by filtration and reused several times without appreciable loss of activity.

추종 로봇의 측정값들을 이용한 다중 이동 로봇의 선도-추종 접근법 기반 군집 제어 (Leader-Follower Based Formation Control of Multiple Mobile Robots Using the Measurements of the Follower Robot)

  • 박봉석
    • 제어로봇시스템학회논문지
    • /
    • 제19권5호
    • /
    • pp.385-389
    • /
    • 2013
  • This paper proposes the leader-follower based formation control method for multiple mobile robots. The controller is designed using the measurements of the follower robot such as the relative distance and angle between the leader and the follower. This means that the follower robot does not require the information of the leader robot while keeping the desired formation. Therefore, the proposed control method can reduce the communication loss and the cost for hardware. From Lyapunov stability theory, it is shown that all error signals in the closed-loop system are uniformly ultimately bounded. Finally, simulation results demonstrate the effectiveness of the proposed control system.

유체로 채워진 보어홀 속의 파이프 종진동에 있어서 방사손실에 의한 감쇠 (Damping due to Radiation Loss for Axial Vibration of the Pipe in a Fluid-filled Borehole)

  • 이현엽;류황진
    • 소음진동
    • /
    • 제7권4호
    • /
    • pp.631-636
    • /
    • 1997
  • A method to estimate the radiatio power to the surrounding formation due to axial vibration of the pipe in a fluid-filled borehole has been developed, by using the propagation modes of stress wave in an infinitely-long and uniform drilling borehole surrounded by a radially-infinite homogeneous formation. Also, the equivalent damping coefficient for the axial vibration of the pipe has been derived. As an example, results for a real drilling borehole has been presented. The analysis of the elastic motion of the infinite formation which has cylidrical cavity is simplified with the geometric axisymmetry and the low-frequency assumption so that the analytic solution is obtained.

  • PDF

레이저 가열 위치에 따른 확산화염의 매연생성 및 산화 특성 변화 (The Effects of Laser Heating on the Soot Formation and Oxidation of a Diffusion Flame)

  • 이원남;남연우;이춘범;신현동
    • 한국연소학회:학술대회논문집
    • /
    • 한국연소학회 2004년도 제28회 KOSCO SYMPOSIUM 논문집
    • /
    • pp.112-117
    • /
    • 2004
  • The effects of laser heating on soot formation and oxidation of propylene diffusion flames have been studied experimentally under nearly sooting conditions. The non-sooting flame can be converted to a sooting flame when the laser light heats up a flame at 7 mm height, while a sooting flame can be changed to a non-sooting flame when a flame is heated with laser light at flame height of 13 mm. The selective heating at the soot formation and/or oxidation region determines the sooting behavior of a diffusion flame. The increased soot/flame temperatures are most likely to be responsible for both the decreased and increased soot formation/oxidation.

  • PDF

DUST SHELL MODELS FOR LOW MASS-LOSS RATE OXYGEN-RICH AGB STARS

  • SUH KYUNG-WON
    • 천문학회지
    • /
    • 제38권2호
    • /
    • pp.267-270
    • /
    • 2005
  • We investigate the spectral energy distributions (SEDs) of low mass-loss rate O-rich asymptotic giant branch (AGB) stars using the infrared observational data including the Infrared Space Observatory (ISO) data. Comparing the results of detailed radiative transfer model calculations with observations, we find that the dust formation temperature is much lower than 1000 K for standard dust shell models. We find that the superwind model with a density-enhanced region can be a possible alternative dust shell model for LMOA stars.

급경사 복원 농경지 토양 유실 저감을 위한 개량제 효율 및 현장 적용성 평가 (Evaluation of Amending Materials to Reduce Soil Loss from Sloping Remediated Agricultural Land)

  • 황원재;박민석;현승훈;지원현;이상환
    • Ecology and Resilient Infrastructure
    • /
    • 제4권3호
    • /
    • pp.180-185
    • /
    • 2017
  • 광산 활동에 의해 오염된 농경지의 복원은 개량제 처리와 복토를 기반의 미량원소 안정화 기법으로 진행되고 있다. 최근 복원된 부지 중 경사 농경지에서 토양 유실 문제가 대두되고 있다. 본 연구에서는 4종의 개량제 (벤토나이트, 석회, 유기물, 제강슬래그)를 다양한 비율로 단일 또는 복합처리 한 후 입단 형성의 효율을 평가했다. 복토재는 점토함량이 다른 3가지 토양 (A 토양=9.4%, B토양=14.7%, C 토양=21.2%)을 대상으로 했다. 단일처리 결과, A 토양은 유기물 5%, B와 C 토양은 석회 5%가 각 토양의 대조구에 비해 입단 형성이 가장 효과적이었다. 9가지 복합처리구 중에서 A 토양은 유기물 3% + 석회 1%, B와 C 토양은 유기물 1% + 석회 3% 처리구의 입단 형성이 가장 높았다 (A 토양=30.4%, B 토양=25.0%, C 토양=36.5%). 현장처리를 위해 각 복토재 (A 토양=0.045, B 토양=0.051, C 토양=0.054)와 국내 농경지의 평균 (0.032) 토양침식인자 차이만큼을 개량제에 의한 목표 입단 형성량으로 설정하였다(29.1% 입단형성). 비용편익을 고려한 최적 개량제 선정한 결과 A와 B 토양은 석회 3%, C 토양은 석회 5%가 가장 적합 했으며, 이를 통한 경사진 복원된 경사 농경지에서 토양 유실을 효과적이고 경제적으로 저감할 것으로 예측된다. 본 연구에서 석회 처리에 의한 토양 알칼리도 상승은 고려하지 않았다.

고주파 기판용 PTFE 복합체 형성 압력에 따른 유전 특성 (Dielectric Characteristics of Polytetrafluoroethylene-based Composites for Microwave Substrates with Formation Pressure)

  • 최홍제;전명표;조용수;조학래
    • 한국전기전자재료학회논문지
    • /
    • 제26권6호
    • /
    • pp.429-433
    • /
    • 2013
  • PTFE composites for use of microwave substrate were fabricated by impregnation and heat treatment fabrication with glass fabric. This study shows dielectric properties such as dielectric constant and loss can be controlled by thickness of PTFE composite with change of pressure condition in heating press process. The dielectric constant of the PTFE composites has decreasing tendency as given higher pressure condition. The dielectric loss has similar result too. Especially, the case of the dielectric loss was affected by the condition of pressure at heating press and had the best performance under 3 MPa. In order to see the reason why thickness conditions make different, their microstructures were also observed.

Al 합금용탕(合金熔湯)의 $C_2C_{l6}$정제(錠劑)-탈(脫)가스에 의한 Mg의 손실(損失) (A Study on the Mg-Loss of Al-Alloy Melt by $C_2C_{l6}$-Tablet Degassing)

  • 이진형
    • 한국주조공학회지
    • /
    • 제1권3호
    • /
    • pp.14-18
    • /
    • 1981
  • The Mg-loss of AlSi 7% melts containing from 0 to 0.8% Mg during the Hexachloroethane tablet degassing was investigated. The results of the experiment was discussed in view of the free energy change and kinetics of $MgCl_2$ formation. The melts with Mg content less than 0.5% showed a Mg-loss proportional to Mg-content, while it was constant at about 24% of the weight of tablets, when Mg content of the melt became more than 0.5 %. The rate of Mg-loss was drastically reduced, when the amount of tablets used at a time increased ver a certain limit for a given melt quantity.

  • PDF