• Title/Summary/Keyword: $CH_2Cl_2$

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MO Interpretation for the trans Effect of Square Planar Type Pt(Ⅱ) Complexes (사각평면형 백금(Ⅱ) 착물의 트란스효과에 대한 분자궤도함수론적 해석)

  • Byung-Kak Park;Lee Sang-Hyup;Hwhan-Jin Yeo;Iee-Yeung Cho
    • Journal of the Korean Chemical Society
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    • v.32 no.5
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    • pp.495-500
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    • 1988
  • The trans effect has been interpreted for a series of trans-[PtNH$_3$Cl$_2$2L] (L = H$_2$O, NH$_3$, Cl$^-$, Br$^-$, I$^-$, CH$_3$ and PH$_3$) and PtCl$_4^{-2}$ by means of our modified-EHMO method. The calculation shows that reduced overlap population(ROP) of Pt-N bond trans to L is decreased with a better trans director. That is, the trans effect has been found to be enhanced with a better trans director. Accordingly, it could be interpreted quantum chemically the trans effect for a general trans-PtTL$_2$X complex.

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Study on the Sister Chromatid Exchange Inducibility in Chinese Hamster Don Cell by Metal Compounds in Work Enviroment

  • Seo, Kwang-Seok;Lee, Chong-Sam
    • Journal of Environmental Health Sciences
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    • v.22 no.1
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    • pp.91-98
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    • 1996
  • 산업장이나 생활환경에서 접하기 쉬운 수용성 염화물을 중심으로 19개 원소 24종의 금속화합물이 Chinese Hamster Don 세포에 있어서의 sister chromatid exchange(SCE) 출현빈도에 미치는 영향을 조사하였다. Chinese Hamster Don 세포에 대한 자매염색분체 교환출현빈도의 증가가 $CrO_3, K_2CrO_4, K_2Cr_2O_7, MnCl_2, K_2SeO_3, CH_3HgCl$ (p<0.01), $CoCl_2, Na_2HAsO_4, HgCl_2$ (p<0.05) 9종의 금속화합물에서 나타났으며, dose-response relationships이 현저한 금속화합물은 6가 크로화합물과 $K_2SeO_3$이었다.

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Sensitivity Characteristics on the Composition Change of the Gas Sensing Materials based on $In_2O_3$ Semiconductor. ($In_2O_3$계 반도성 가스감지재료의 조성변화에 따른 감도특성)

  • 정형진;유광수
    • Journal of the Korean Ceramic Society
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    • v.22 no.4
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    • pp.54-60
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    • 1985
  • Gas sensing materials for detecting flammable gases such as $CH_4$, $C_3H_8$ and n-$C_4H_{10}$ were developed by util-izing $In_2O_3$ as the principal sensing material. The sensing materials were formulated by mixing $In_2O_3$ powder with one or two other chemicals such as $SnO_2$, $Y_2O_3$ and $Al_2O_3$ with a small addition of $PdCl_2$ as a catalyst. Sample of sensor were fabricated by coating each of the mixtures on a ceramic tube impregnating ethylsili-cate and firing at 75$0^{\circ}C$ Each material mixture was evaluated by measuring and comparing gas sensitivity(resistance in air/resistance with gas) to flammable gases such as $CH_4$, $C_3H-8$ and n-$C_4H_{10}$. It was found that among fifteen compositions tested three compositions as follows show the highest gas sensitivity and thus are very feasible for commercialization as the gas sensors ; o49.5 $In_2O_3$+50 Al2O3_0.5 PdCl2(wt%) o $20In_2O_3+29$ $SnO_2+50$ $Al_2O_3+1$ $PdCl_2$(wt%) o40 $In_2O_3$+9 $Y_2O_3+50$ $Al_2O_3+1$ $PdCl_2$(wt%)

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Bond Orbital Theory of Chemical Reactivity (反應性의 結合 Orbital 理論)

  • Yang, Kang;Ree, Tai-Kyue
    • Journal of the Korean Chemical Society
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    • v.8 no.1
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    • pp.20-24
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    • 1964
  • The linear combination of bond orbitals method is used to investigate the reactivity of halomethanes in abstraction reactions by atoms. The activation energy is evaluated on the assumption that, in an activated complex, two electrons in a bond to be broken become completely isolated from the rest of the ${\sigma}$-electron systems. Such a model leads to an intuitively attractive concept that the interactions between the reactive bond and the neighboring bonds govern the reactivity of ${\sigma}$-electron systems. The resulting equation for the activation energy, ${\varepsilon},\;is:\;{\narepsilon}= ${\varepsilon}={\zeta}+$$${\sum}_{i=1}^3$${\eta}c-I,$ c-4 Here, subscript C-4 indicates the bond to be broken, while C-i represents the other three bonds surrounding the reactive bond; ξ is the activation energy of a hypothetical reaction of an isolated C-4 bond and an attacking atom; and ${\eta}$C-i,C-4 stems from the stabilizing interacting of C-4 bond with neighboring C-i bonds. A choie of η′s consistent with bond strength data simplifies the above equation to a form ${\varepsilon}={\zeta}\;+\;N{\eta}c$-H, C-4 where N denotes the number of C-H plus C-F bond in halomethanes. In agreement with this equation, experimental -values increase linearly with increasing N.

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Effects of Dipping and Preheating Treatments on Susceptibility to Browning of Potato Slices During Cold Storage (침지용액과 예열 처리가 감자 슬라이스의 냉장 중 갈변정도에 미치는 영향)

  • 정현미;이귀주
    • Korean journal of food and cookery science
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    • v.12 no.4
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    • pp.535-540
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    • 1996
  • Potato slices were dipped in solution of 2% CaCl$_2$, and 1% chitosan or preheated in each of these solutions for refrigeration for 4 weeks at 5$^{\circ}C$. Changes in L value, content of total phenol and chlorogenic acid and po lyphenol oxidase activity were determined. During refrigeration, it was found that L values of potato slices treated with CaCl$_2$, (CaPS) and those treated with chitosan (ChPS) increased. Contents of total phenol and chlorogenic acid of potato slices decreased, While potato slices preheated in CaCl, solution (Hcaps) showed much decreases. And polyphenol oxidase (PPO) activity of potato slices decreased except CaPS and decreases in PPO activities were much larger in preheated potato slices. From these results, of those treatments used, chitosan treatment combined with preheating have shown to be effective to control enzymatic browning of potato slices during refrigeration.

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The performance of solar heat pump with non-freon refrigerant $CF_3CH_2F$(R-134a) for school classroom heating[II] (태양열 이용 비프레온계 $CF_3CH_2F$(R-134a)적용 열펌프시스템에 의한 학교교실 난방에 관한 연구(II))

  • Sun, Kyung-Ho;Jung, Hyun-Chai;Kim, Ki-Sun
    • Solar Energy
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    • v.17 no.1
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    • pp.3-15
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    • 1997
  • The goal of this paper is to measure and compare the performance of solar heat pump for school classroom heating. To accomplish the goal, solar heat pump with alumium roll bond type evaporator and indoor heat exchanger(condenser) was built and fully instrumented with thermocouples and pressure transducers etc. The test results showed that the COP and capacity of R-134a($CF_3CH_2F$) were higher than those of R-12($CF_2Cl_2$). The solar heat pump system for room heating was designed to show the best efficiency that the room temperature make $18{\sim}20^{\circ}C\;and\;23{\sim}25^{\circ}C$ in Seoul during November, December, and January.

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Strengthening of conventional dental glass ionomer cement by addition of chitosan powders with low or high molecular weight (저/고분자량 키토산에 의한 종래형 치과용 글라스아이오노머 시멘트의 강화)

  • Kim, Dong-Ae;Kim, Gyu-Ri;Jun, Soo-Kyung;Lee, Jung-Hwan;Lee, Hae-Hyoung
    • Korean Journal of Dental Materials
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    • v.44 no.1
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    • pp.69-77
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    • 2017
  • The aim of this study was to investigate the effects of chitosan powder addition on the strengthening of conventional glass ionomer cement. Two types of chitosan powders with different molecular weight were mixed with conventional glass ionomer cement (GIC): low-molecular weight chitosan (CL; 50~190 kDa), high-molecular weight chitosan (CH; 310~375 kDa). The chitosan powders (CL and CH) were separately added into the GIC liquid (0.25-0.5 wt%) under magnetic stirring, or mixed with the GIC powder by ball-milling for 24 h using zirconia balls. The mixing ratio of prepared cement was 2:1 for powder to liquid. Net setting time of cements was measured by ISO 9917-1. The specimens for the compressive strength (CS; $4{\times}6mm$), diametral tensile strength (DTS; $6{\times}4mm$), three-point flexure (FS; $2{\times}2{\times}25mm$) with flexure modulus (FM) were obtained from cements at 1, 7, and 14 days after storing in distilled water at $(37{\pm}1)^{\circ}C$. All mechanical strength tests were conducted with a cross-head speed of 1 mm/min. Data were statistically analyzed by one-way ANOVA and Tukey HSD post-hoc test. The mechanical properties of conventional glass ionomer cement was significantly enhanced by addition of 0.5 wt% CL to cement liquid (CS, DTS), or by addition of 10 wt% CH (FS) to cement powder. The CL particles incorporated into the set cement were firmly bonded to the GIC matrix (SEM). Within the limitation of this study, the results indicated that chitosan powders can be successfully added to enhance the mechanical properties of conventional GIC.

Identification of Anti-obesity Constituents from Yukeuigambitang (육의감비탕(肉薏減肥湯)의 항비만 효능 및 유효성분 규명)

  • Wang, Shian;Song, Hyo-Nam;Choi, Won-Ik;Park, Jong-Hyuk;Jeong, Youg-Joon;Kang, Se-Chan;Ko, Sung-Kwon;Bhang, Dae-Hyuk
    • Korean Journal of Plant Resources
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    • v.25 no.2
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    • pp.271-276
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    • 2012
  • To develop antiobese food materials from medicinal plants, isolation of antiobese active compounds in $Yukeuigambitang$ of which activity was already proved in the previous study by animal experiments was performed. Antiobese effect of stepwise solvent fractions from 70% ethanol extract of $Yukeuigambitang$ was determined by the differentiation inhibition activity on 3T3-L1 preadipocytes. CH2Cl2 fraction had significant antiobese activity, and n-Hexane and EtOAc fractions were the next. Three phenolic compounds from $CH_2Cl_2$ fraction were identified by GC/MS analysis and one compound was finally isolated by HPLC. It was revealed as a new compound presumed to be one of the derivatives produced from the medicinal plants mixture in $Yukeuigambitang$.

A Study on the Physical Properties of Compound of Pyrazine with Cromium Trioxide (Pyrazine의 Cr$O_3$ 화합물의 물성에 관한 연구)

  • Jung Sung Yang
    • Journal of the Korean Chemical Society
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    • v.33 no.1
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    • pp.11-17
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    • 1989
  • Pyrazinium chlorochromate and dipyrazinium trichromate which are pyrazinium salts were prepared by the each reaction of pyrazine with chromium trioxide under the presence of HCl and $CH_2Cl_2$. These compounds wese nonhygroscopic and were solved in water very well. Physical properties such as solubility, pH, electrical conductivity, and melting point were measured. These compounds were considered to be ionic ; $C_4H_4N_2H^+$, $CrO_3Cl^-$, $Cr_3O^{2-}_{10}$ by the measurement of electrical conductivity. It was found that CrO$_3$ was formed in the first decomposition process of salts and it was changed into $Cr_2O_3$ in the second process as its weight is decreased. It was also found that especially under the same condition dipyrazinium salt was in the form of isopoly ($Cr_2O^{2-}_{10}$)anion which has been thought to be in the form of $Cr_2O^{2-}_{7}$ obtained from pyridine.

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구리 폐촉매 재처리

  • Lee, Gwang-Ho;Lee, Seung-Gon;Sin, Seung-Ho;Song, Yun-Seop
    • Proceedings of the Korean Institute of Resources Recycling Conference
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    • 2004.05a
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    • pp.59-65
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    • 2004
  • 동제련 공정중 Smelting에서 SiO2가 없으면 산화에 의한 생성물은 Molten Cu-Fe-O 'Oxysulphide' 와 Solid Magnetite가 된다. 이 생성물은 Cu-rich Liquid와 Cu-dilute Liquid로 분리가 불가능하다. Smelting의 목적이 Cu가 높은 Matte와 산화된 불순물의 효과적인 분리에 있으므로 이와 같은 분리가 불가능한 혼합상태를 분리해 주어야 한다. 이때 SiO2가 첨가되면 Cu-rich 상인 Matte가 FeO-rich상인 Slag로의 분리가 가능해진다. 이러한 의미에서 동제련에 있어서 규사의 성분은 매우 중요하며 현재 재생사를 규사로 대체 사용하고 있다. 한편 실리콘 모노머 합성 공정인 금속 규소와 접촉 물질(Contact Mass, 구리촉매와 조촉매)을 반응시켜 (Si+CH3Cl ${\rightarrow}$ (CH3)2SiCl3) 실리콘 모노머를 생산하는 공정중 반응이 끝난 접촉물질인 구리 폐촉매가 발생되는데 주요성분이 Cu 12%, Si80%로 재생사와 유사하여 동제련에 투입 가능 여부를 판단하기 위하여 각 공정에서의 용융실험을 통하여 결론을 도출하였고, 실 조업 Test를 거쳐 처리하게 되므로 구리 회수 및 폐기물로써의 매립을 중지 할 수 있었다.

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