• 한국식품조리과학회지
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• 제7권1호
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• pp.45-51
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• 1991

1. 유지의 지방산 조성 분석시 GC의 경우 Oleic acid/Elaidic acid를 분리 측정하지 못하였으나 그 외 지방산들(Myristic acid, Palmitic acid, Stearic acid, Linoleic acid, Lindenic acid, Arachidonic acid)에 있어서는 재현성이 높았으며 HPLC는 Stearic acid, Elaidic acid, Linoleic acid Arachidonic acid 검출에 높은 재현성을 나타냈으나 Palmitic acid/Oleic acid를 분리하지 못하였으며 CGC는 Elaidic acid를 제외한 모든 지방산들에 있어서 좋은 측정능력을 보였주었다. 2. 지방산의 cis/trans 기하 이성체의 측정시에는 CGC가 가장 능력이 뛰어났고 HPLC도 양호하였으나 GC는 Oleic acid/Elaidic acid 이성체 측정이 불가능하였다. 또한 각 지방산 분석에 소요된 평균 시간은 GC가 7.21분, CGC가 9.84분, 그리고 HPLC는 24.48분으로서 GC와 CGC의 경우는 비슷하나 HPLC는 다른 기기에 비해 약2.5∼3배의 많은 시간이 소요되었다. 3. 이들 3가지 분석기기로 실제 유지식품인 대두유(CSOY, DSOY)의 지방산조성을 분석한 결과, 정제된 대두유(CSOY)는 Linoleic acid, Oleic acid, Palmitic acid, Linolenic acid가 주요구성 지방산인 반면 Stearic acid는 소량으로 함유되어 있었으며, 미정제 대두유(DSOY)에서는 Linoleic acid, Oleic acid, Palmitic acid, Stearic acid가 주요 구성 지방산이었고 Linolenic acid는 아주 미량 함유되어 있었다. 이때 3가지 분석기기의 대두유의 지방산 분석능력은 표준지방산 분석의 지방산 분석능력은 표준지방산 분석시에 나타난 결과와 동일하였다. 따라서 GC, CGC및 HPLC의 분석특징으로 GC의 경우 분석소요시간이 CGC나 HPLC에 비해 짧은 반면 이성체 분리가 불가능하였으며 HPLC는 분석소요시간이 다른 기기에 비해 다소 긴 반면 이성체 측정이 가능하였고 포화지방산보다는 불포화지방산 측정에 다소 유리하였다. 그리고 CGC의 분석특성에 있어서 재현성, 분석 소요시간 및 이성체 분리능력이 GC나 HPCL에 비해 우수한 것으로 평가되었다.

• Bulletin of the Korean Chemical Society
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• 제21권10호
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• pp.1052-1054
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• 2000

Binding geometries of $[Ru(II)(110-phenanthroline)_2L]^2+$, complexes (where L = dipyrido [3,2-a:2',3'-c]phena-zine (DPPZ) or benzodipyrido[3,2-a:2',3'-c] phenazine (BDPPZ)) to poly(dG)${\cdot}$poly(dC)${\cdot}$poly(dC) + triplex DNA (CGC + triplex) has been investigated by linear dichroism and normal absorption spectroscopy. Analysis of the linear dichroism for the CGC+ triplex and $[Ru(II)(phen)_2BDPPZ]^2+$ complex indicates that the extended ligand of the metal complex lie perpendicular to the polynucleotide helix axis. Together with strong hypochromism and red shift in the interligand absorption region, we concluded that the extended BDPPZ or DPPZ ligand in-tercalated between the bases of polynucleotide. The spectral properties of the metal complexes bound to CGC+ triplex are similar to those bound to $poly(dA)[poly(dT)]^2$ triplex (Choi et al., Biochemistry 1997, 36, 214), sug-gesting that the metal complex is located in the minor groove of the CGC+ triplex.

• 폴리머
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• 제30권5호
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• pp.432-436
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• 2006

인덴과 메틸인덴 리간드를 가지고 폴리메틸렌 다리결합으로 구성된 두 금속 CGC (constrained geometry complexes) 촉매를 합성하여 에틸렌과 스티렌 공중합을 행하였다. 촉매 구조에 따른 공중합 활성과 공중합체의 구조 및 열적 성질을 조사하였다. 12-메틸렌 및 9-메틸렌 다리결합을 가진 촉매의 환성은 상업용 CGC 촉매와 6-메틸렌 다리결합을 가진 촉매의 활성보다 4배 이상 높게 나타났는데, 이는 6-메틸렌 다리결합은 입체적으로 중심금속간은 인접한 거리에 위치하게 되어 입체장애에 의해 촉매활성이 감소하게 된다. 다리결합의 길이가 긴 두 금속촉매를 사용하여 제조한 공중합체의 스티렌 함량이 6-45 mol%로 나타났으며, 단량체 공급비([Styrene]/[Ethylene])가 5.0 이상에서는 다리결합의 길이가 긴 촉매로 얻은 공중합체의 $T_m$이 관찰되지 않는 비결정의 공중합체가 생성되었으며, 스티렌의 함량이 증가할수록 공중합체의 $T_m$은 급격히 감소하여 스티렌 함량이 약 11mol% 이상에서는 결정성이 없는 랜덤 공중합체가 생성되었다. C-NMR로 공중합체의 미세구조를 분석한 결과 스티렌 블록이 존재하지 않는 랜덤 공중합체임을 확인할 수 있었다.

• 폴리머
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• 제35권6호
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• pp.505-512
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• 2011

Para-xylene의 기본 구조로 연결된 4개의 이핵 CGC를 활용하여 에틸렌과 1-헥센의 공중합특성을 조사하여 중합촉매의 구조적인 특징이 중합에 미치는 영향을 조사하였다. 4가지의 이핵 constrained geometry catalyst(CGC) 중에서 3가지는 모두 para-xylene 다리로 연결되어 있으나 벤젠고리 부분에 각각 다른 치환체가 결합된 것으로서 치환체는 수소(Catalyst 1), isopropyl(Catalyst 2), n-hexyl(Cataylst 3)이고, n-octyl(Catalyst 4)인 화합물이었다. 이핵 메탈로센 4가지와 Dow 촉매를 사용하여 에틸렌과 1-헥센을 공중합시켜 다른 치환체를 가진 다리리간드의 구조적인 특성변화가 촉매의 중합특성과 이로부터 생성되는 공중합체의 특성에 미치는 영향을 조사하였다. 실험 결과 다리리간드의 특성에 따라 분명한 경향성과 차이점이 발견되었다. 중합활성은 치환체의 크기가 가장 작은 수소에서 가장 높았으며, isopropyl에서 가장 낮았으며 그 차이는 최대 3배 이상이었다. 반면 분자량은 치환체가 isopropyl인 촉매에서 생성된 공중합체가 가장 컸고, n-hexyl과 1-octyl 치환체 화합물에서 가장 작은 분자량의 공중합체가 생성되었으며 그 차이는 6배에 달하였다. 이핵 CGC의 공중합 특성은 치환체가 긴 알킬기인 n-hexyl 및 1-octyl 화합물이 가장 우수하여 동일한 조건에서 1-헥센을 가장 많이 함유하여 40% 이상의 1-헥센을 포함하는 에틸렌 공중합체를 제조할 수 있었다. 이러한 연구 결과는 촉매구조 변화에 의한 고분자 미세구조 조절이라는 고분자 합성의 가장 어려운 부분이 xylene 다리를 가진 이핵 CGC의 치환체를 조절함으로써 가능함을 보여주는 결과이다.

• 한국환경복원기술학회지
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• 제11권3호
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• pp.129-138
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• 2008

This study was carried out to examine the growth condition of Chionanthus retusa, roadside tree in Cheongyechon (CGC) and to investigate the relationship soil characteristics and tree vitality and chlorophyll contents of it. Growth condition of tree (condition of flower, leaves and branch, % of flowering, height, diameter at breast height, width, vitality and chlorophyll contents) and physiochemical relation item (pH, organic matter, K, Mg, Na, Ca, P) were investigated. The result are as follows : 1. The growth condition of flower, leaves and branch in the left side of CGC is better than the right side since the quantity of sunshine of left side of CGC is much more than the right side. 2. The average pH was alkaline. P and organic contents were much lower than the standards. 3. Tree vitality and chlorophyll contents were bad where were high user density and high buildings, such as 1, 2 area near Jong-gak and jongro 3 ga. Among the physiochemical factors of soil which affect tree vitality, K and P were found to be the main factors. Therefore, in order to improve the growth environment of roadside tree in CGC, it is needed to do periodical soil fertilizing and improve physical characteristics of soil such as, permeability and porosity by soil conditioner.

• 한국재료학회지
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• 제27권8호
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• pp.451-458
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• 2017

The service life of coal gangue concrete(CGC) strongly depends on the capillary water absorption, this water absorption is susceptible to freeze-thaw cycles. In this paper, the cumulative water absorption and sorptivity were obtained to study the effects of 0, 0.5, 1.0, and 1.5 % steel fiber volume fraction added on the water absorption of CGC. Sorptivity and freeze-thaw tests were conducted, and the capillary water absorption was evaluated by the rate of water absorption(sorptivity). Three prediction models for the initial sorptivity of steel fiber reinforced coal gangue concrete(SFRCGC) under freeze-thaw cycles were established to evaluate the capillary water absorption of SFRCGC. Results showed that, without freeze-thaw cycles, the water absorption of CGC decreased when steel fiber at 1.0 % volume fraction was added, however, the water absorption increased with the addition of 0.5 or 1.5 % steel fibers. Once the SFRCGC specimens were exposed to freeze-thaw cycles, the water absorption of SFRCGC significantly increased, and 1.0 % steel fiber in volume fraction added to CGC caused the lowest water absorption, except for the case of the sample without steel fibers added. The CGC with steel fiber at 1.0 % volume fraction performed better. The SFRCGC has a strong response to freeze-thaw cycles. Results also showed that the linear function prediction model is practical in the field of engineering because of its simple form and a relatively high precision. Although the polynomial prediction model presents the highest computation precision among the three models, the complicated form and too many coefficients make it impractical for engineering applications.

• Bulletin of the Korean Chemical Society
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• 제14권1호
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• pp.34-34
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• 1993

The gelation phenomena of N-methylolated PAAm (M-PAAm) in aqueous media was studied. The critical gelation concentration (CGC) was very close to the calculated $C^*$ of the scaling theory. But the CGC of lower MW M-PAAm deviated from $C^*$ due to contamination of small molecules. We propose that the CGC is the close packing configuration of polymer molecules in solution. The experimental results of the gelation of M-PAAm/PAAm mixture proved that the close packing configuration is essential to make a gel. We calculated the minimum quantity of M-PAAm to make M-PAAm/PAAm mixture a gel by using the close packing configuration. We used a lattice model.

• The Korean Journal of Physiology and Pharmacology
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• 제20권4호
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• pp.399-406
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• 2016

Early life neuronal exposure to environmental toxicants has been suggested to be an important etiology of neurodegenerative disease development. Perfluorohexanesulfonate (PFHxS), one of the major perfluoroalkyl compounds, is widely distributed environmental contaminants. We have reported that PFHxS induces neuronal apoptosis via ERK-mediated pathway. Imperatorin is a furanocoumarin found in various edible plants and has a wide range of pharmacological effects including neuroprotection. In this study, the effects of imperatorin on PFHxS-induced neuronal apoptosis and the underlying mechanisms are examined using cerebellar granule cells (CGC). CGC were isolated from seven-day old rats and were grown in culture for seven days. Caspase-3 activity and TUNEL staining were used to determine neuronal apoptosis. PFHxS-induced apoptosis of CGC was significantly reduced by imperatorin and PD98059, an ERK pathway inhibitor. PFHxS induced a persistent increase in intracellular calcium, which was significantly blocked by imperatorin, NMDA receptor antagonist, MK801 and the L-type voltage-dependent calcium channel blockers, diltiazem and nifedipine. The activation of caspase-3 by PFHxS was also inhibited by MK801, diltiazem and nifedipine. PFHxS-increased ERK activation was inhibited by imperatorin, MK801, diltiazem and nifedipine. Taken together, imperatorin protects CGC against PFHxS-induced apoptosis via inhibition of NMDA receptor/intracellular calcium-mediated ERK pathway.

• Macromolecular Research
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• 제12권1호
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• pp.100-106
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• 2004

We have prepared the polymethylene-bridged, dinuciear, half-sandwich constrained geometry catalysts (CGC)［Zr(η$\^$5/:η$^1$-C$\_$9/H$\_$5/SiMe$_2$NCMe$_3$)］$_2$［(CH$_2$)$\_$n/］［n=6(9), n=12(10)］by treating 2 equivalents of ZrCl$_4$with the corresponding tetralithium salts of the ligands in toluene. $^1$H and $\^$13/C NMR spectra of the synthesized complexes provide firm evidence for the anticipated dinuciear structure. In $^1$H NMR spectra, two singlets representing the methyl group protons bonded at the Si atom of the CGC are present at 0.88 and 0.64 ppm, which are considerably downfield positions relative to the shifts of 0.02 and 0.05 ppm of the corresponding ligands. To investigate the catalytic behavior of the prepared dinuciear catalysts, we conducted copolymerizations of ethylene and styrene in the presence of MMAO. The prime observation is that the two dinuclear CGCs 9 and 10 are not efficient for copo-lymerization, which definitely distinguishes them from the corresponding titanium-based dinuclear CGC. These species are active catalysts, however, for ethylene homopolymerization; the activity of catalyst 10, which contains a 12-methylene bridge, is larger than that of 9 (6-methylene bridge), which indicates that the presence of the longer bridge between the two active sites contributes more effectively to facilitate the polymerization activity of the dinuciear CGC. The activities increase as the polymerization temperature increases from 40 to 70$^{\circ}C$. On the other hand, the molecular weights of the polyethylenes are reduced when the polymerization temperature is increased. We observe that dinuciear metallocenes having different-length bridges give different polymerization results, which reconfirms the significant role that the nature of the bridging ligand has in controlling the polymerization properties of dinuclear catalysts.

• Macromolecular Research
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• 제10권6호
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• pp.359-364
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• 2002

A series of PLA-PEO-PLA triblock stereo-copolymers with varying PLA/PEO and L-DL-LA ratios were synthesized via ring opening pelymerizations. Aqueous solutions of these copolymers undergo thermo-responsive phase transitions as the temperature monotonically increases. Further study shows that there is a critical gel concentration (CGC), and also lower and upper critical gel temperatures (CGTs), at which the thermo-responsive phase transition occurs. The CGC and CGTs are affected by various factors such as block length, as well as the compositions of the PLA blocks and of the additives. In particular, the changes in the phase diagram produced by varying the L-/DL-LA ratio in the PLA blocks were determined to be mainly due to consequent stereo-regularity changes in the PLA blocks.