• 제목/요약/키워드: Concept of Chemical Change

검색결과 62건 처리시간 0.025초

A study of Energy Oriented Urban Development Model for Industrial Complex plan

  • Kim, Sang-hyun
    • 기술혁신학회지
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    • 제8권1호
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    • pp.209-219
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    • 2005
  • o Korea consumed total 198.5 million TOE and the portion of crude oil n was 100.4 million TOE in 2002 which marked the 10th largest energy consuming country and ranks the $4^{th}$ crude oil consumer in the world. o Industries consumed 51.5% of the total energy and 93% of industrial energy was used at the manufacturing industries such as steel, textile, chemical, food and beverage, pulp and paper, and timber industries, which lead to energy intensive industries numbered 110,000. o Also Korea ranks the $10^{th}$ greenhouse gas emission countries of the world (134.9 million TC) which may cause Korean industries to suffer severely during the implementation of United Nations Framework Convention on Climate Change (UNFCCC). o Therefore, the target of the study is to develop a model for the analysis and design of industrial complex by integration of the energy usage and environmental problems. o The research work contents are as followings: -Analysis of Korea energy consumption -Concept of the integration of energy and environment problems - Basic concept of industrial complex planning - Case study (1) - Recommendation and conclusion

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Bioproduct 분리를 위한 결정화 연구 동향 (Technological Trend of Crystallization Research for Bioproduct Separation)

  • 김우식;이은규
    • KSBB Journal
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    • 제20권3호
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    • pp.164-176
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    • 2005
  • In bioengineering field, current academic trends and informations on crystallization technology for bioproduct separation were summarized. It is essential for utilizing the crystallization technology to understand the fundamental phenomena of crystallization of crystal nucleation, crystal growth, crystal agglomeration and population balance for the design of crystallizers. In general, the crystal nucleation that the crystalline solids occur from the solution is analyzed by Gibb's free energy change in the aspect of thermodynamics and in the present paper the crystal nucleation models based on the above thermodynamics are summarized by their key characteristics. The crystal growth and agglomeration, which have been studied over 50 years and are essential phenomena for separation technology, are reviewed from their basic concept to most leading edge trend of researches. In the material and population balances for the designs of crystallization separation process, the analysis of crystallizers is summarized. Thereon, the present review paper will academically contribute the understanding the crystallization phenomena and the design of the crystallization separation process.

熱力學函數間의 直線關係 (第 5 報) 關係式의 評價와 反應機構上의 意義 (Linear Relationships between Thermodynamic Parameters (Part V) Critical Evaluation and Mechanistic Significances of the Relationship)

  • 이익춘
    • 대한화학회지
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    • 제9권1호
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    • pp.8-15
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    • 1965
  • 一般式中의 potential energy 變數로서 ${\sigma}$ Y를 使用할 수 있음을 밝혔고 또 關係式의 反應機構上의 意義를 論하였다. Benzyl chlorides의 solvolysis反應 data를 適用함으서 物質常數 ${\alpha}'$는 2個의 뚜렷한 系列을 形成하며 置換基常數 ${\sigma}$와는 各系列마다 別途로 直線關係를 가지며 이로서 $S_N1$으로부터 $S_N2$로의 反應機構의 變化를 알 수가 있었다.

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Smartphone-based Chemistry Instrumentation: Digitization of Colorimetric Measurements

  • Chang, Byoung-Yong
    • Bulletin of the Korean Chemical Society
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    • 제33권2호
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    • pp.549-552
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    • 2012
  • This report presents a mobile instrumentation platform based on a smartphone using its built-in functions for colorimetric diagnosis. The color change as a result of detection is taken as a picture through a CCD camera built in the smartphone, and is evaluated in the form of the hue value to give the well-defined relationship between the color and the concentration. To prove the concept in the present work, proton concentration measurements were conducted on pH paper coupled with a smartphone for demonstration. This report is believed to show the possibility of adapting a smartphone to a mobile analytical transducer, and more applications for bioanalysis are expected to be developed using other built-in functions of the smartphone.

센서 응용을 위한 다공성 골드의 제조 (Preparation of Porous Gold for Sensor Applications)

  • 김영훈;김휘로;고재욱
    • 한국가스학회지
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    • 제12권2호
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    • pp.32-37
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    • 2008
  • U-safety system 구축을 위한 휴대 및 설치가 편리한 액상/기상 센서가 요구되고 있다. 나노다공성 알루미나를 구조유도체로 사용한 다공성 골드(Au)를 제조하여 센서의 전극 및 센서기질로 사용하였다. 제조한 다공성 골드는 평균 $200{\sim}300\;nm$의 윈도우 기공을 갖고, $4.8\;m^2/g$의 비표면적을 갖는 100% 순수한 골드로 구성되어 있다. 다공성 골드는 우수한 전기전도성, 불순물의 탈 부착에 따른 저항 변화 측정의 간편성, 좋은 재현성을 가져 액상/기상 센서의 기질로 사용하기에 적합하다. 본 연구에서는 검증실험으로 실시간 수은 검출실험을 실시하여, 센서로서의 활용 가능성을 확인하였다.

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Flexible NO2 gas sensor using multilayer graphene films by chemical vapor deposition

  • Choi, HongKyw;Jeong, Hu Young;Lee, Dae-Sik;Choi, Choon-Gi;Choi, Sung-Yool
    • Carbon letters
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    • 제14권3호
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    • pp.186-189
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    • 2013
  • We report a highly sensitive $NO_2$ gas sensor based on multi-layer graphene (MLG) films synthesized by a chemical vapor deposition method on a microheater-embedded flexible substrate. The MLG could detect low-concentration $NO_2$ even at sub-ppm (<200 ppb) levels. It also exhibited a high resistance change of ~6% when it was exposed to 1 ppm $NO_2$ gas at room temperature for 1 min. The exceptionally high sensitivity could be attributed to the large number of $NO_2$ molecule adsorption sites on the MLG due to its a large surface area and various defect-sites, and to the high mobility of carriers transferred between the MLG films and the adsorbed gas molecules. Although desorption of the $NO_2$ molecules was slow, it could be enhanced by an additional annealing process using an embedded Au microheater. The outstanding mechanical flexibility of the graphene film ensures the stable sensing response of the device under extreme bending stress. Our large-scale and easily reproducible MLG films can provide a proof-of-concept for future flexible $NO_2$ gas sensor devices.

Enhanced Anti-reflective Effect of SiNx/SiOx/InSnO Multi-layers using Plasma Enhanced Chemical Vapor Deposition System with Hybrid Plasma Source

  • Choi, Min-Jun;Kwon, O Dae;Choi, Sang Dae;Baek, Ju-Yeoul;An, Kyoung-Joon;Chung, Kwun-Bum
    • Applied Science and Convergence Technology
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    • 제25권4호
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    • pp.73-76
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    • 2016
  • Multi-layer films of $SiN_x/SiO_x$/InSnO with anti-reflective effect were grown by new-concept plasma enhanced chemical vapor deposition system (PECVD) with hybrid plasma source (HPS). Anti-reflective effect of $SiN_x/SiO_x$/InSnO was investigated as a function of ratio of $SiN_x$ and $SiO_x$ thickness. Multi-layers deposited by PECVD with HPS represents the enhancement of anti-reflective effect with high transmittance, comparing to the layers by conventional radio frequency (RF) sputtering system. This change is strongly related to the optical and physical properties of each layer, such as refractive index, composition, film density, and surface roughness depending on the deposition system.

1,3-bisdicyanovinylindane을 이용한 산성가스 감지용 화학 센서 제작 (Fabrication of Chemical Sensors for the Detection of Acidic Gas using 1,3-bisdicyanovinylindane)

  • 송환문;박영민;손영아;이창수
    • Korean Chemical Engineering Research
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    • 제46권1호
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    • pp.184-188
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    • 2008
  • 본 연구는 산도 변화에 따라 색이 빠르게 변하는 특성을 가지고는 있는 반응성 염료(1,3-bisdicyanovinylindane)를 이용하여 신속하고 정확한 산성가스 검출을 위한 화학적 센서 제작을 위한 방법을 제안하였다. 반응성 염료(1,3-bisdicyanovinylindane)는 산성 상태에서 염료와 양성자의 해리되어 흡광도의 변화를 이용하면 손쉽게 미세화학센서를 제작 할 수 있었다. 또한, 반응성 염료는 수용액 상태에서 매우 안정적인 음전하를 지니고 있어 양전하를 지니는 고분자 전해질과 쉽게 layer-by-layer(LBL) 방법을 이용하여 다층 박막 구조를 쉽게 구현할 수 있었다. 먼저, 마이크로스탬프 위에 비반응성 염료와 양전하 고분자 전해질을 적층하여 다층박막을 형성한 후 센서기판에 프린팅한다. 이후 지시염료와 양전하 고분자 전해질을 다시 적층하여 최종 가스센서를 구현한다. 고안된 가스 센서는 산성가스와 반응을 통해 사용자에게 주의를 유도하는 해골 모양을 표현하여 실제 응용성을 보여주었다. 제시된 산성가스 감지센서는 첫째로 제작 과정이 매우 단순하며 저비용이고 둘째로 완성된 감지센서는 환원 과정을 통해 여러번 재사용될 수 있으며 마지막으로 센서 제작 공정이 매우 단순하며 수용액을 기반으로 하는 환경친화적 방법이다.

생활화학제품 관련 기업의 책임 이행 현황과 과제 (Corporate Responsibility for Consumer Chemical Products in Korea)

  • 이준철;김신범
    • 한국환경보건학회지
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    • 제45권4호
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    • pp.321-325
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    • 2019
  • The recent humidifier disinfectant disaster has caused a great change in our society and lead the Korean people to lose faith in the government and corporations. To overcome this mistrust, the government and corporations have undertaken certain efforts, including a voluntary agreement on consumer product safety. All the ingredients of a consumer product should be disclosed according to this voluntary agreement. There were also unexpected benefits occuring from this process. We found that the concept of corporate responsibility for product safety differed greatly among the various actors in Korean society. Corporations believed that a product could be considered safe if it contained no regulated substances. We have come to believe that this may be an important cause of the humidifier disinfectant disaster. The Korean government, corporations, and civil organizations have reached a consensus that it is a corporation's responsibility to evaluate the risks of products before they are introduced to the market. However, the limitations of these voluntary efforts are clear, and the legal system needs to be improved. We suggest that the concept of extreme recklessness should be introduced into regulations on product safety.

고압하에서의 전지의 기전력과 열역학적 성질 (The Electromotive Force and Thermodynamic Properties of the Cell at High Pressure)

  • 지종기;정종재;황정의
    • 대한화학회지
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    • 제18권5호
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    • pp.320-328
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    • 1974
  • 종래의 방법으로 고압하에서 전지의 표준기전력 $(E^{\circ})$를 산출하는 것은 불가능하다. 그러나 완전평형상수의 개념을 종래의 Nernst 방정식에 적용하므로서 고압하에서 표준기전력을 구할 수 있게 되었다(완전 Nernst방정식). 더욱이 다른 열역학적 성질 이를테면 수화수의 순변화(k), 용매의 압축을(${\beta}$), 전지반응에서 종래의 해리상수(K) 평형상태에서 표준자유에너지변화(${\Delta}G^{\circ}$) 표준엔탈피변화(${\Delta}H^{\circ}$) 및 표준엔트로피변화($S^{\circ}$) 등을 얻었다. 본 실험에서는 전지의 기전력(E)을 $20{\sim}35^{\circ}C$와 1∼2500 atms 범위에서 측정하였다. 일정한 온도에서 전지의 기전력은 압력이 증가함에 따라 증가하였으며, 일정한 압력에서 온도가 증가함에 따라 역시 증가하였다. 전지반응의 수화수의 순변화(k)는 $20^{\circ}C$에서 41.96으로서 압력에 따라 변하지 않고 일정한 값을 유지하였으나 한편 K와 ${\Delta}S^{\circ}C$는 압력에 따라 증가하였으나 ${\Delta}G^{\circ}$${\Delta}H^{\circ}$는 감소하였다. 고압하에서도 완전 Nernst방정식으로부터 표준기전력을 계산할 수 있으므로 상압에서와 마찬가지로 화학평형론을 취급할 수 있게 되었다

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