• Journal of the Korean Chemical Society
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• v.60 no.5
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• pp.362-373
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• 2016

In this study, ionic compound in the science textbooks developed under the 2009 revised national curriculum were analyzed in terms of the scientific concept and model description and the student understanding through the questionnaires. Analysis of textbooks was performed for science2 of middle school and chemistry I & II of high school. Questionnaire was carried out with 194 students including middle school 2nd grade and high school 1st-3rd grade. The results are as follows: First, as a result of analysis of textbooks, scientific concepts and models used to explain the ionic compound showed differences depending on the types of textbooks. In addition, scientific models were provided with or without explanation for the scientific concepts. Second, analysis of the questionnaire showed that students didn’t properly understood scientific concepts and models in the ion formation, stoichiometric ratio between ions.

• Journal of the Korean Chemical Society
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• v.59 no.6
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• pp.499-507
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• 2015

The purpose of this study is to investigate middle school students’ understanding of ionic equation. Two hundreds and nineteen middle school students were participated in the study. After six class hours of learning ‘electrolyte and ion’ unit, instrument was implemented to evaluate students’ understanding of ionic process and ability to write ionic equation. We analyzed the influence of characteristics of ionic compounds on correct answer rate. In addition, knowledge state of students required for writing ionic equation was analyzed. The results were as follows: First, ionic compounds tested were categorized into six groups. The correct answer rate was different depending on the characteristics of each group. Second, knowledge state required for writing ionic equation was structured. Based on results some suggestion were made to develope effective learning strategy for understanding ionic equation.

• Journal of the Korean Ceramic Society
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• v.38 no.5
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• pp.431-437
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• 2001

본 연구에서는 양이온 교환반응에 의해 Na-Mont와 R$_{11}$SO$_4$로부터 R$_{11}$SO$_4$-Mont 층간화합물을 합성한 후, 이 R$_{11}$SO$_4$-Mont 층간화합물을 다시 제 4차 유기 양이온인 (Et)$_4$N$^{+}$ 이온 및 (Bu)$_4$N$^{+}$ 이온과 반응시켜 그 거동을 살펴보았다. R$_{11}$SO$_4$-Mont를 (Et)$_4$N$^{+}$이온과 반응시켰을 대보다 (Bu)$_4$N$^{+}$ 이온과 반응시킨 경우에 좀 더 큰 층간거리가 얻어졌다. R$_{11}$SO$_4$-Mont를 (Et)$_4$N$^{+}$이온 및 (Bu)$_4$N$^{+}$과 반응시켜 얻은 층간화합물을 다시 아세토니트릴, 에탄올 및 디옥산과 팽윤반응을 수행한 결과 층간거리가 확장되었으나, 이는 Na-Mont를 R$_{11}$SO$_4$와 48시간 교환 반응시킨 후에 교환용액 하에서 얻은 R$_{11}$SO$_4$-Mont의 층간거리에 불과했다. 원소분석결과, R$_{11}$SO$_4$-Mont와 (Bu)$_4$N$^{+}$를 반응시킬 경우 반응이 반응식 b에 의거 진행되고, (Bu)$_4$N-Mont를 R$_{11}$SO$_4$와 반응시킬 경우에는 반응식 c에 의거 진행됨을 예측할 수 있었다.의거 진행됨을 예측할 수 있었다.

• The Journal of Engineering Research
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• v.6 no.2
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• pp.119-124
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• 2004

In this research montmorillonite intercalations complexes as organophilic clay compounds which have very different properties as the starting clay mineral were synthesized by the substitution of metal ions which exist in the montmorillonite layers with the organic cations which have long alkyl chain by the cation exchange reaction. Thereafter the obtained products dried in high vacuum were treated with the various swelling liquids such as dist. water, methanol, acetone, ether and acetonitrile in order to know the swelling behaviour of the synthesized complexes. Especially for this research Korean and Turkish clays were selected to compare the intercalations complexes of both clays and their swelling behaviour.

• Journal of Environmental Science International
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• v.2 no.1
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• pp.61-72
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• 1993

Result of this study indicate that two criteria must be met in order to have effective macrocycle-mediated transport in these emulsionsystem. First, one must effective extraction of the post transition metals, $Cd^{2+}$. $Pb^{2+}$ and $Hg^{2+}$ , into toluene membrane. The effectiveness of this extraction is greatest if log K values for the metal-macrocycle interaction is large. Second, the ratio of the log K values for the metal ion-receiving phase to the metal ion-macrocycle interaction must be large enough to ensure quantitative stripping of the metal ion at the toluene phase interface. Control of the first step can be obtained by appropriate selection of macrocycle donor atom, substituents, and cavity radius. The second step can be controlled by selecting the proper complexing agent for inclusion in the receiving phase. The order of the transport, when using the several $A^-$ species such as $SCN^-$, $1^-$, $Br^-$ and $Cl^-$ is the order of the changing degree of solvation for $A^-$ and the transport of the metals is also affected by the control of concentration for receiving species because of solubility-differences. In this study, we can seperate each single metal ion from the mixture of $Cd^{2+}$, $Pb^{2+}$, and $Hg^{2+}$ ions by using the toluene membranes controlled by optimized conditions. Transport of the single metal is also very good, and alkaline and alkaline earth metals as interferences ions did not affect the seperation of the metals in this macrocycle-liquid membrances but transition metal ions were partially affected as interferences for the post transition metal ions.

• Journal of the Korean Chemical Society
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• v.56 no.6
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• pp.739-750
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• 2012

The purpose of this study is to analyze the cognitive demands level of the description about 'pure substance and mixture compound', 'ionic compound', 'molecule' on the 'science2' textbooks by the 2007 revised curriculum. The three types of Curriculum Analysis Taxonomy have been used to analyze the cognitive demands level of those contents on the 6 kinds of 'science2' textbooks. The first, the cognitive demand level about 'pure substance and mixture compound' on many textbooks is a late concrete operational stage because of class inclusion and hierarchical classification. And the descriptions as 'pure substance is conserved even when mixed with other pure substance' is a early formal operational stage. The second, the cognitive demand level about 'ionic compound' and 'molecule' is a early formal operational stage, because of "Formal modeling is the indirect interpretation of reality by deductive comparison from a postulated system with its own rules" and "Atoms have a structure". The third, the terms as 'ionic bonding', 'ionic compound', 'chemical formula', 'covalent bonding', 'covalent compound', and 'molecular formula' have been used on many 'science2' textbooks. Those terms would be used later on 'chemistry I' and 'chemistry II' in senior high school but not even 'science3' and 'science'.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.229-229
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• 1994

선택성이 높고 뛰어난 약효를 지닌 항 바이러스제의 개발은 신약개발의 중요한 영역중에 하나이다. 현재 AIDS 치료제로 사용되고 AZT를 비롯하여 항virus 효과를 나타내는 약물의 대부분은 구조적으로 nucleoside계에 속하는 화합물로서 수 많은 약리학적 연구 및 합성 화학적 연구가 이루어져 왔다. 특히 합성 화학적 측면에서 이들 화합물의 합성은 크게 두가지로 나누어지는데 그것은 sugar 부위의 변형을 통한 방법과 염기 부위의 변형을 통한 방법에 의해 새로운 항 바이러스제를 개발하는 것이다. 최근의 연구 동향에 있어서 주목할 만한 변화의 하나는 sugar 부위의 구조적 변형을 시도하는데 있어서 종래의 5원환 형태에서 환이 개열된 형태의 acyclic nucleoside에 대한 연구가 이루어져 좋은 효과를 거두고 인다는 사실이다. Acyclovir, Ganciclovir등 의 개발이 그것이다. 본 연구에서는 종래의 acyclic nucleoside가 ribose sugar의 2'번 및 3'번 탄소를 제거한 acyclic ether 형태로 되어있는 것과는 다르게 ether 부위의 산소를 탄소 치환한 carbo-acyclic nucleoside를 합성하고자 하였다. Acyclic nucleoside를 합성하고자 하였다. Acyclic nucleoside의 side chain의 conformation이 항 바이러스 작용을 나타내는데 필수 불가결한 점을 감안할때, carbo-acyclic nucleoside계 화합물은 보다 다양하게 변형될 수 있는 장점을 가지고 있다. 이러한 관점에서 side chain의 2'번 및 3'번 탄소는 side chain의 conformation을 좌우하는 결정적 요인으로 작용할 것으로 판단된다. 따라서 본 연구에서는 이들 탄소를 중심으로한 분자수식을 시도하기로 하고 bioisosterism을 이용하여 3'위치의 수소를 fluoride로 치환한 화합물을 설계하여 합성을 시도하였다.silyl group-5'-무치환 화합물을 tosyl, azido화 한다음 desilylation하여 얻었다. 목적하는(1) 화합물의 diasteromer 인 2',3'-dihydroxy-5'-무치환 유도체(3)는 (4)화합물 합성시 얻은 hemiactal을 key intermediate로 하여 TsNHNH$_2$, NaB(CN)H$_3$ 및 NaOAc로 처리하므로서 얻을수 있었다. 이들 화합물들의 각종 DNA 및 RNA virus에 대한 항 바이러스작용을 검토한 결과 현저한 항 바이러스 작용을 나타내지 않았다.분화유도 활성을 나타내어 항종양제로의 개발에 많은 흥미가 기대된다.기대된다.oxylic acid (compound 10)를 합성하였다.10^{－7}$ M)에 의한 단백인산화에 대하여는 더 미약한 억제-효과를 나타내었다. 이상의 결과는 PDE-1과 항우울약들의 항혈소판작용은 PKC-기질인 41-43 kD와 20 kD의 인산화를 억제함에 기인되는 것으로 사료된다.다. 것으로 사료된다.다.바와 같이 MCl에서 작은 Dv 값을 갖는데, 이것은 CdCl$_{4}$$^{2-}$ 착이온을 형성하거나 ZnCl$_{4}$$^{2-}$ , ZnCl$_{3}$$^{-}$같은 이온과 MgCl$^{+}$, MgCl$_{2}$같은 이온종을 형성하기 때문인것 같다. 한편 어떠한 용리액에서던지 NH$_{4}$$^{+}$의 경우 Dv값이 제일 작았다. 바. 본 연구의 목적중의 하나인 인체유해 중금속이온인 Hg(II), Cd(II)등이 NaCl같은 염화물이 함유된 시료용액에 공해이온으로 존재할 경우 흡착에 의한 제거가 가능하다. 한편 이같은 중금속이온의 흡착실험은 특히 해수중의 금속이온의 회수연구에도

• The Journal of Natural Sciences
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• v.5 no.1
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• pp.77-86
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• 1992

By cation-exchange-reaction long-chain organic cationic tensides can be intercalated in the montmorillonite layer space, and thus intercalations-complexes of montmorillonite with different properties of materials can be obtained. Such intercalations-complexes are finding strong technical appliances in many areas and are also used very often as model-systems for studying behaviors of materials. Therefore in this research intercalations-complexes of montmorillonite with organic cationic tensides ad model-systems were synthesized and their behabiors under various different conditions were studied.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2002.11a
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• pp.123-127
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• 2002

DRAM용 capacitor의 차세대 전극물질 후보 중의 하나인 Ru 박막을 고밀도의 ECR 플라즈마를 이용하여 식각 특성 및 식각 메커니즘을 알아보고자 하였다. 식각시 Ru은 oxygen들과 결합을 하여 RuO2 화합물들을 생성하고 RuO2 화합물들은 다시 oxygen들과 결합을 함으로써 휘발성이 강한 RuOx 화합물들을 생성하였다. 하지만 이러한 식각이 이루어지기 위해서는 oxygen이온들에 의한 충돌이 필요하며, Cl과 F 가스들을 첨가가 의해 충돌 이온의 에너지가 증가되어 RuO2와 O radical들의 반응성을 향상시켰다. 이에 휘발성이 좋은 RuO4들의 형성속도를 증가시킴으로써 식각 속도를 향상시킬 수 있었다.

• Journal of the Korean Chemical Society
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• v.38 no.11
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• pp.808-818
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• 1994

The neutral compounds [$MCl_3L_2$(MeCN)] (M = Mo, V: L = $PPh_3$, 1/2 phda) have been prepared from the reaction of starting material $MCl_z$ (M = Mo; z = 5, M = V; z = 3) with N,P-donating ligands in acetonitrile solution. Addition of $AgClO_4$ to these neutral monomeric compounds in acetone solution were produced [$MCl_3-_nL_2(MeCN)(S)_n$]$(ClO_4)_n$ (n = 1, 2 : s = solvent). Finally treatment of bivalent cationic compound and neutral compound was formed chloride bridged dinuclear complex $[(MeCN)(L)_2ClM({\mu}-Cl)_2M'Cl(L)_2(MeCN)](ClO_4)_2$ and treatment of univalent cationic compound with half equivalent pyrazine to pyrazine bridged complex $[(MeCN)(L)_2Cl_2M({\mu}-pyz)M'Cl_2(L)_2(MeCN)](ClO_4)_2$. These complexes are characterized by elemental analysis, $^1H$, $^{13}C$ NMR, IR, Far-IR and UV-Vis spectroscopy.