• 제목/요약/키워드: wet method

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습식법으로 제조된 BN 중간층을 가진 Cf/SiC 복합재의 제조 및 물성 평가 (Fabrication and Characterization of Cf/SiC Composite with BN Interphase Coated by Wet Chemical Process)

  • 구준모;김경호;한윤수
    • 한국표면공학회지
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    • 제50권6호
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    • pp.523-530
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    • 2017
  • In this study, we developed the h-BN interphase for ceramic matrix composites (CMCs) through a wet chemical coating method, which has excellent price competitiveness and is a simple process as a departure from the existing high cost chemical vapor deposition method. The optimum condition for nitriding an h-BN interphase using boric acid and urea as precursors were derived, and the h-BN interphase coating through a wet method on a carbon preform of 2.5 D was conducted to apply the optimum conditions to the CMCs. In order to control the coating property via the wet coating method, four parameters were investigated such as dipping time of the specimen in the precursor solution, the ratio of boric acid and urea in the precursor, the concentration of solution where the precursor was dissolved, and the cycle of dipping and dry process. The CMCs was fabricated through polymer impregnation and pyrolysis (PIP) processes and a three-point flexural strength test was conducted to verify the role of the coated h-BN interphase.

현미중(玄米中) 카드뮴의 분석방법(分析方法)에 관(關)한 비교연구(比較硏究) (Comparison of the analytical methods for Cd in brown rice)

  • 김복영;이민효
    • 한국환경농학회지
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    • 제14권3호
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    • pp.338-344
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    • 1995
  • 현미중 카드뮴의 분석을 위한 보다 효율적인 방법을 찾기 위해 현미중 카드뮴의 공정시험방법을 표준으로 수종의 습식 및 건식방법에 대해 카드뮴의 회수율, 표준편차 및 표준방법과의 상관성등을 비교, 검토한 결과 현미 시료량 50g, 회화온도 $600^{\circ}C$의 건식방법은 회수율이 79.6%로 표준분석방법(87.2%)을 제외한 타 분석방법보다 높고, 표준편차도 평균${\pm}2.6$으로 표준분석방법의 평균+6.4 보다 약간 작았으며, 표준분석방법으로 분석된 카드뮴함량과의 상관성($r=0.977^{\ast\ast}$)도 크게 높아 본 방법은 습식으로 분해하는 현행 수질오염 공정시험 방법과 함께 현미중 카드뮴 분석방법으로 사용하여도 좋을 것으로 판단된다.

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의영 전의이씨 출토복식의 세척방법에 관한 연구 (A Study on the Cleaning Method of Excavated Textiles)

  • 박윤미;황은경;정복남
    • 복식문화연구
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    • 제11권6호
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    • pp.956-966
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    • 2003
  • The purpose of study is to find out a suitable cleaning method for excavated textiles of Jeon-ui Lee(1570∼1647). The textiles were excavated from her tomb in 1997, and her descendents put them in a box without any treatment and kept them in the warehouse since then. We used two kinds of silk as samples, non-dyed and dyed textile. The experiment was performed by 8 kinds of wet cleaning and dry cleaning methods, an ultrasonic cleaner was used in the wet cleaning, decane and perchloroethylene were used as solvents in the dry cleaning. The use of the ultrasonic cleaner in the wet cleaning method did not show any damage to the fibers of the textiles and it not only cleaned well but also was safe for the fugitive dyes. It resulted in more effective cleaning when the detergent was used together. Therefore, it is effective to use the ultrasonic cleaning on the delicate historical textiles and helpful to the operator's safety and environment.

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준설토를 이용한 지하구조물 뒷채움 다짐특성에 관한 연구 (The Study on the Compaction Characteristics of Underground Structural Backfill with Reclaimed Soil)

  • 김영웅;박기순;손형호;김종국
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 1999년도 봄 학술발표회 논문집
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    • pp.357-364
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    • 1999
  • The purpose of this study is to analysis the grain distribution and compaction characteristics of structural backfill with reclaimed soil. Five(5) reclaimed soil samples which passed #200 sieve have been used in the test. The study showed that the maximum dry density and the bearing value rate turned out to be becoming smaller when the more the quantity passed #200 sieve, the smaller the soil grain. The maximum dry density value calculated from the compaction md relative density test showed wet method > compaction method > dry method. The correlation coefficient between Rc and Dr based on the grain distribution and the compaction characteristics showed that the maximum dry density value by the wet method is little higher than the compaction method and dry method.

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일지역 후기 학령기 남자 아동의 몽정에 대한 지식 정도 (Knowledge of Nocturnal Emissions in Late Elementary School Boys in Incheon)

  • 이용화
    • 부모자녀건강학회지
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    • 제12권1호
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    • pp.77-87
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    • 2009
  • Purpose: The purpose of this study was to determine the knowledge of nocturnal emissions, or wet dreams and to provide information for developing a wet dream education program for elementary school boys. Method: The research design was a descriptive study through questionnaires. Data was collected from May 10, 2009 to May 20, 2009. A total of 197 late elementary school boys in Incheon, Korea participated in this study. Data was analyzed using the SPSS WIN 15.0 program. Result: The results of this study were as follows; Knowledge of wet dreams in late elementary school boys was low; The mean of the information about wet dreams was 14.00 on a 100 point scale; There were significant differences of knowledge regarding wet dreams according to the educational experience at 6 items and wet dreams experience at 12 items of total 21 items. This indicates that present education for wet dreams is not efficient and does not provide appropriate information when they need practical information. Conclusion: Self education learning program for wet dreams should be developed for late elementary school boys which includes different contents and time required for further study, evaluation and assessment.

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Comparison of Heat Transfer and Pressure Drop Characteristics of Heat Exchangers Having Plain Fins Under Dry and Wet Conditions

  • Kim Nae-Hyun;Sin Tae-Ryong;Lee Eung-Ryul
    • International Journal of Air-Conditioning and Refrigeration
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    • 제13권3호
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    • pp.128-137
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    • 2005
  • In this study, dry and wet surface pressure drop and heat transfer characteristics of heat exchangers having plain fins were investigated. Nine samples having different fin pitches and rows were tested. The wet surface heat transfer coefficient was reduced from experimental data using enthalpy-potential method. The wet surface heat transfer coefficients were approximately equal to the dry surface values except for one row configuration. For one row configuration, the wet surface heat transfer coefficients were approximately $30\%$ lower than the dry surface values. For the pressure drop, the wet surface yielded approximately $30\%$ higher values compared with the dry surface counterpart. Data were compared with existing correlations.

평판휜 열 교환기의 건표면, 습표면 열전달 및 압력손실에 관한 연구 (Heat Transfer and Pressure Drop Characteristics of Heat Exchangers Having Plain Fins Under Dry and Wet Conditions)

  • 민창근;조진표;오왕규;김내현
    • 설비공학논문집
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    • 제16권3호
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    • pp.218-229
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    • 2004
  • In this study, dry and wet surface pressure drop and heat transfer characteristics of heat exchangers having plain fins were investigated. Nine samples having different fin pitches and rows were tested. The wet surface heat transfer coefficient was reduced from experimental data using enthalpy-potential method. The wet surface heat transfer coefficients were approximately equal to the dry surface values except for one row configuration. For one row configuration, the wet surface heat transfer coefficients were approximately 30% lower than the dry surface values. For the pressure drop, the wet surface yielded approximately 30% higher values compared with the dry surface counterpart. Data were compared with existing correlations.

자동렌즈미터를 이용한 소프트 콘택트렌즈의 굴절력 측정 방법에 관한 신뢰도 (Reliability of Measurements of Back Vertex Power for Soft Contact Lenses Using an Auto-Lensmeter)

  • 김건규;이욱진;이선행;곽호원;유동식
    • 한국안광학회지
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    • 제15권1호
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    • pp.39-46
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    • 2010
  • 목적: 자동렌즈미터를 이용한 소프트 콘택트렌즈의 굴절력 측정에서 dry blotting과 wet cell 방법에 따른 신뢰도를 평가하고자 하였다. 방법: 측정에 사용한 소프트렌즈는 현재 국내에서 유통되고 있는 렌즈 5종류, 4개의 굴절력(-1.50D, -3.00D, -6.00D, -9.00D)을 이용하였고, 두 검사자가 자동렌즈미터로 측정하여 반복성과 재현성을 평가하였다. 결과: Dry blotting방법으로 측정한 굴절력의 평균 차이는 0.03~0.18D였으며, 실리콘 하이드로겔 렌즈에서 0.10~0.18D, 하이드로겔 렌즈에서 0.03~0.08D로 나타났다. 두 검사 간의 평균 차이는 0.10D이하로 측정자 간의 재현성이 좋은 것으로 나타났다. Wet cell방법으로 측정한 굴절력의 평균 차이는 0.09~0.69D였으며, 두 검사자 간에 평균 차이는 0.02~0.59D로 나타났으며, 소재에 따른 측정의 신뢰도와 검사자 간의 재현성은 낮았다. 결론: 모든 재질에 대해 dry blotting 방법이 wet cell방법보다 신뢰도가 좋았으며, 두 방법 모두 실리콘 하이드로겔 렌즈에서는 낮은 신뢰도를 보였다. 자동렌즈미터를 이용하여 신속히 후면 정점굴절력을 확인할 필요가 있는 실무 현장에서 dry blotting방법이 효율적인 것으로 판단된다.

젖은 헤어와 털 시뮬레이션을 위한 효율적인 응집력과 강성 처리 (Efficient Treatment of Clumping and Stiffness for Wet Hair and Fur Simulation)

  • 김종현;이정
    • 한국컴퓨터그래픽스학회논문지
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    • 제23권1호
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    • pp.9-16
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    • 2017
  • 젖은 헤어 또는 동물의 털 시뮬레이션에서 응집력과 강성(stiffness)을 처리하는 것은 어려운 문제이다. 격렬한 움직임을 갖는 헤어나 털이 물에 젖게 되면 끝이 뭉치고 빳빳해지는 현상이 나타나게 되는데, 이는 달리는 동물이나 헤드뱅잉 하는 장면 등에서 쉽게 관찰 할 수 있다. 기존의 방법들은 정해진 시뮬레이션 시나리오에서 이 문제를 해결하려고 했지만 여전히 젖은 헤어의 특징을 묘사하기 위한 일반적인 방법이 존재하지 않는다. 이 문제를 해결하기 위해 우리는 응집력과 강성에 대한 새로운 모델링 방법을 제안한다. 기존 연구들은 물이 모발에 흡수되는 현상을 모델링 하는데 초점을 맞춘 반면, 우리는 젖은 모발의 움직임을 사실적으로 표현하는데 집중한다. 젖은 헤어는 마른 헤어와는 다르게 인접한 모발들끼리 응집력이 작용하여 서로 뭉치는 형태를 띄며, 물의 포화도가 높아질수록 빳빳해지는 독특한 물리적 특성이 나타난다. 제안된 기법의 핵심은 SPH (smoothed particle hydrodynamics) 기반의 표면 장력 모델을 확장하여 응집력을 표현하고, 강성 제약을 두어 모발의 탄성력을 조절하는 것이다. 우리 기법은 젖은 모발이 격렬한 움직임에서도 응집력을 잘 유지할 수 있도록 도와주며, 물의 포화도에 따른 모발의 빳빳함을 표현하여 사실적인 젖은 헤어 시뮬레이션 결과를 보여준다.

외단열 고정 방법에 따른 부착강도 변화 (Other Changes in Bond Strength due to External Insulation Method)

  • 김태준;박완구;박진상;오정환;배기선;오상근
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2013년도 추계 학술논문 발표대회
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    • pp.132-133
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    • 2013
  • External Insulation Method is to place the insulation on the outside of concrete. External Insulation Method is better than Internal Insulation Method to the protection of structure. However, The phenomenon that External Insulation falling from the structure occurs frequently. Apply method of External Insulation is divided Wet Construction, Dry Construction and Wet & Dry Construction. The purpose of this study is to test Bonding Strength of External Insuation. Furthermore, on the basis of this study, External Insulation Method determines the effective development will be made.

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