• 대한화학회지
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• 제40권5호
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• pp.365-373
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• 1996

Diethylenedisiloxyl 유연격자를 갖는 일련의 새로운 액정화합물을 합성하여 이들의 액정특성 및 말단의 페닐기에 para 치환기들의 스멕틱 그룹 효율성을 조사하였다. 또 말단그룹의 크기 영향을 알아보기 위하여 para 치환된 페닐 대신 $\beta$-naphthyl 그룹을 도입한 화합물도 아울러 합성하였다. 모든 화합물들은 85-95%의 높은 수율로 합성되었으며, 합성된 화합물들은 모두 양방성 액정 특성을 보여주었다. 이중 $X=NO_2$ 화합물은 $S_A$상을 보였고, 나머지 화합물들은 모두 $S_B$상을 보여주었다. 화합물들의 녹음열은 일반적인 액정화합물들과 비교하여 낮은 값을 나타내었으며 등방화열은 비슷한 값을 보였는데, 치환기의 스멕틱그룹 효율성은 $H 순이었다.

• Bulletin of the Korean Chemical Society
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• 제15권7호
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• pp.553-559
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• 1994

Dynamics of $CH_2CI$ group in ${\alpha},2,6$-trichlorotoluene dissolved in $CDCl_3$ was studied by observing various relaxation modes for $^{13}C$ under proton undecoupled condition. Partially relaxed $^{13}C$ spectra were obtained at $34^{\circ}C$ as a function of evolution time after applying various designed pulse sequences to this $AX_2$ spin system. It was found that nonlinear regression analysis of the relaxation data for these magnetization modes could provide the information about dipolar and spin-rotational auto-correlation and cross-correlation spectral densities for fluctuation of the $^{13}C-^1H$ internuclear vector in $CH_2Cl$ group. The results show that the effect of cross-correlation is comparable in magnitude to that of auto-correlation and the relaxation in this spin system is dominated by dipolar mechanism rather than spin-rotational one. From the resulting spectral density data we could calculate the bond angle ${\angle}HCH\;(105.1$^{\circ}$) and elements of the rotational diffusion tensor for $CH_2Cl$ group.

• Bulletin of the Korean Chemical Society
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• 제23권12호
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• pp.1754-1758
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• 2002

Tetrathiafulvalene(TTF) reacts with $PdCl_2,Pd(NO_3)_2$ and $Pd(hfacac)_2$(hexafluoroacetylacetonate) in ethanol to give $(TTF)_{1.5}PdCl_2$ (1a), $(TTF)_3Pd(NO_3)_2$ (1b) and $(TTF)_4Pd(hfacas)_2$ nd (1c), respectively. $PdCl(TCNQ)_{2.5}{\cdot}CH_3OH(2a)$was obtained from the reaction of $PdCl_2$ with LiTCNQ in methanol via the partial replacement of $Cl^-$ in $PdCl_2$ by $TCNQ^-$anion, whereas the total substitution of the labile $NO_3^-$ in $Pd(NO_3)_2$ yielded pd(TCNQ)·$CH_3OH$ (2b). $Pd(hfacac)_2(TCNQ)_2\cdot3CH_3OH$ (2c) was obtained from $Pd(hfacac)_2$ and LiTCNQ in methanol. The prepared compounds were characterized by spectroscopic (IR, UV, XPS) methods and magnetic (EPR, magnetic susceptibility) studies. The powdered electrical conductivities (${\sigma}_{rt}$) of the prepared compounds at room temperature were about~$10^{-7}S{\cdot}cm^{-1}$. The effective magnetic moments were lass than the spin-only value of one unpaired electron and no EPR signals from Pd metal ions were observed in any of the compounds, indicating that the Pd ions were diamagnetic and the magnetic moments arose from$(TTF)_n$ or $(TCNQ)_n$ moieties. The experimental evidences revealed that the charge transfer had occurred form $(TTF)_n$ moiety to the central Pd metal ion in 1a, 1b and 1c. Thus the TTF donors were ions in 2a and 2b were diamagnetic Pd(II) oxidation state. In contrast, the Pd metal ion was oxidized to Pd(IV) state in 2c as a result of an addition of $TCNQ^-$anion to $Pd(hfacac)_2$ in methanol. The oxidation states of the Pd metal ions were confirmed using the x-ray photoelectron spectroscopy.

• 한국전기전자재료학회논문지
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• 제21권4호
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• pp.354-361
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• 2008

The dielectric characteristics of low-k interlayer dielectric materials was fabricated by plasma enhanced chemical vapor deposition (PECVD). BTMSM precursor was evaporated and introduced with the flow rates from 16 sccm to 25 sccm by 1sccm step in the constant flow rate of 60 sccm $O_2$ in process chamber. Manufactured samples are analyzed components by measuring FT/IR absorption lines. Decomposition each Microscopic structures through two-dimensional correlation analysis about mechanisms for the formation of SiOCH in $SiOCH_3$, Si-O-Si and Si-$CH_3$ bonding group and analyzed correlation between the micro-structure of each group. It is a tendency that seems to be growing of Si-O-Ci(C) bonding group and narrowing of Si-O-$CH_3$ bonding group relative to the increasing flow-rate BTMSM. The order of changing sensitivity about changes of flow-rate in Si-O-Si(C) bonding group is cross link mode$(1050cm^{-1})$ $\rightarrow$ open link mode$(1100cm^{-1})\rightarrow$ cage link mode $(1140cm^{-1})$.

• 한국산업융합학회 논문집
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• 제7권1호
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• pp.107-113
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• 2004

Several transition metal complexes, [$M(L)X_2$](M=Pd(II), Ni(II); X=CI, Br) are prepared with aminophosphine ligands such as 1,2-bis{(diphenylphosphino)amino}ethane{$Ph_2PNHCH_2CH_2NHPPh_2$}($L_1$), 1,2-bis{(diphenylphosphino)amino}propane{$Ph_2PNHCH(CH_3)CH_2NHPPh_2$}($L_2$), trans-1,2-bis{(diphenylphosphino)amino}cyclohexane{$Ph_2PNHC_6H_{10}NHPPh_2$}($L_3$) and 1,2-bis{(diphenylphosphino)amino}benzene{$Ph_2PNHC_6H_4NHPPh_2$}($L_4$). The properties of these complexes are characterized by optical spectroscopic methods including UV/vis spectroscopy, CD, IR, $^1H$- and $^{31}P-NMR$ together with conductometer and elemental analysis. All complexes are stable under atmospheric environment. Catalytic reactivity for C-C coupling between [$M(L)X_2$] and Grignard reagents(RMgX; R=phenyl, propyl, buthyl) by thermolysis were investigated utilizing GC/mass, $^1H$- and $^{13}C-NMR$. When mol scale is 1:20 at [$Pd(L)Cl_2$] and Grignard reagents, the high catalytic activity for C-C coupling is apparent. The [$M(L)X_2$](X=Cl, Br) complexes which have strong bond at M-P exhibit high yields for C-C coupling reactions. When the central metal ion is Pd(II), the high catalytic activity for C-C coupling is apparent. The complex coordinated with Br shows higher catalytic activity for C-C coupling reactions compared to Cl.

• 한국식품영양과학회지
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• 제31권5호
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• pp.814-818
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• 2002

배추김치의 dichloromethane(CH$_2$Cl$_2$)획분, ethylacetate (EtOAc) 획분 그리고 물($H_2O$)획분이 1% 콜렛테롤 식이를 16주 동안 섭취한 토끼의 심장, 신장, 그리고 폐의 지질 축적에 미치는 영향에 대한 연구로 100g 식이에 첨가한 김치 용매획분의 양은 8.3mg CH$_2$Cl$_2$, 5.6mg EtOAc 그리고 221.9mg $H_2O$ 획분으로 이 양은 5% 동결건조 김치속에 들어있는 양이다. 토끼는 각 군당 6마리로 한 마리씩 사육하였다. 16주 사육 후 심장, 신장 그리고 폐의 콜레스테롤 및 중성지질의 농도는 대조군에 비해 김치 용매획분에 의해 현저하게 감소하였고, 인지질과 총지방질 함량은 CH$_2$Cl$_2$획분군에서만 유의적으로 감소하였다. (p<0.05). 심장에 있어서 콜레스테롤 농도는 CH$_2$Cl$_2$획분, EtOAc획분 그리고 $H_2O$획분군에서 42%(p<0.05), 21%(p<0.05) 그리고 8%감소하였고, 중성지질 농도는 각 29%(p<0.05), 4%, 그리고 11% 감소하였다. 신장의 경우 콜레스테롤은 CH$_2$Cl$_2$획분, EtOAc획분 그리고 $H_2O$획분군에서 23, 12, 그리고 11% 감소하여 유의적으로 (p<0.05) 억제되었고, 중성지질은 CH$_2$Cl$_2$획분과, $H_2O$획분군에서 각 51%와 21% 감소하여 유의적인 차이를 나타내었다. 폐의 경우 Ch$_2$Cl$_2$획분, EtOAc획분 그리고 $H_2O$획분군에서 콜레스테롤 (-37, -20, 22%) 및 중성지질(-39, -28, -28%) 모두 유의적으로 (p<0.05) 감소하였다. 장기별로 비교해 볼 때 콜레스테롤 함량은 폐, 신장, 심장 순으로 높았고, 중성지방 함량은 심장, 신장, 폐 순으로 높게 나타났다. 인지질 함량은 심장, 신장 그리고 폐에서 비슷하나 수준을 나타냈다. 이러한 결과를 살펴보았을 때 김치용매획분중 CH$_2$Cl$_2$획분에 지질을 감소시키는 활성성분이 가장 많이 함유된 것으로 생각된다.

• Archives of Pharmacal Research
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• 제21권4호
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• pp.436-439
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• 1998

In order to find out anti-platelet activating factor (PAF) from natural resources, Korean medicinal plants used for the treatments of peripheral circulation disorders were tested for their possible protective effects on PAF-induced anaphylactic shock. From the above screening, the methanol extract of Gentiana scabra showed a potent antagonistic activity against PAF. Water suspension of the extract was partitioned with $CH_2$$CI_2$ and EtOAc, successively. The EtOAc fraction which showed the highest activity was chromatographed on silica gel to yield 6 fractions. From the fraction which showed higher PAF-antagonistic activity than the other fractions, compound 1 was isolated by recrystallization. On the basis of spectral data, compound 1 was identified as 2-hydroxy-3-methoxybenzoic acid glucose ester. The compound prevented the mice from the PAF-induced death at a dose of 300 $\mu\textrm{g}$/mouse.

• Journal of Photoscience
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• 제9권2호
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• pp.66-69
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• 2002

Zinc chlorin 1 possessing tertiary 3$^1$_hydroxy and 13$^1$-oxo groups was synthesized as a model for the antenna chlorophylls of photosynthetic green bacteria. Self-aggregation of 1 in nonpolar organic solvents was examined and compared to 2 and 3 possessing a secondary and primary 3$^1$_hydroxy group, respectively. Zinc chlorin 1 self-aggregated in I％(v/v) CH$_2$Cl$_2$-hexane to form oligomers and showed a red-shifted Qy maximum at 704 nm compared to the monomer (648 nm in CH$_2$CI2$_2$). This red-shift is larger than that of 3$^1$S-2 (648 to 697 nm) and comparable to that of3$^1$R-2 (648 to 705 nm), but smaller than that of 1 (648 to 740 nm), indicating that while a single 3$^1$-methyl group (primary to secondary OH) suppressed tight and/or extended aggregation, the additional 3$^1$-methyl group (secondary to tertiary OH) did not further suppress aggregation. The relative stability of the aggregates was in the order 3> 3$^1$R-2∼ 1 > 3$^1$S-2 as determined by visible spectral analyses. Molecular modeling calculations on oligomers of zinc chlorins 1, 3$^1$ R-2 and 3 gave similar well-ordered energy-minimized structures, while 3 stacked more tightly than 3$^1$ R- 2 and 1. In contrast, 3$^1$S-2 gave a relatively disordered (twisted) structure. The calculated oligomeric structures could explain the visible spectral data of 1-3 in nonpolar organic solvents. Moreover, self- aggregation of synthetic zinc 13$^1$_oxo-hlorins 4-6 possessing a 2-hydroxyethyl, 3-hydroxypropyl and 3- hydroxy-I-propenyl group at the 3-position in nonpolar organic solvents was discussed.

• 전자공학회논문지CI
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• 제46권4호
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• pp.87-93
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• 2009

무선 메쉬 네트워크(Wireless Mesh Networks, WMNs)는 유비쿼터스 환경 및 무선 브로드밴드 액세스를 제공하기 위한 핵심적인 미래 기술로 대두되고 있다. WMN에서의 전체적인 성능은 채널의 간섭을 최소화함으로써 개선될 수 있다. WMN에서 주로 사용하는 네트워크 인터페이스 기술 중 하나인 IEEE 802.11b/g 스펙은 3 개의 멀티 채널을 지원한다. 이러한 멀티 채널 WMN에서 효율적인 채널 할당을 위해서는 채널 스캐닝 지연과 채널 의존성 문제를 고려해야 한다. 본 논문에서는 IEEE 802.11b/g WMN에서의 이러한 문제점들을 해결하기 위해 클러스터 기반의 채널 할당(Cluster-Based Channel Assignment, CB-CA) 알고리즘을 제안한다. CB-CA 알고리즘에서는 클러스터 헤드(Cluster Head, CH) 노드들 간에는 동일 채널을 사용함으로써 채널 스캐닝과 채널 스위칭을 수행하지 않는다. 해당 클러스터 멤버 (Cluster Member, CM) 노드들과의 통신에는 CH들 간의 통신 채널에 영향을 미치지 않는 채널을 할당함으로써 멀티채널에서 발생할 수 있는 간섭을 최소화 할 수 있다. 시뮬레이션 결과 본 논문에서 제안한 CB-CA 알고리즘이 WMNs의 성능을 향상시킬 수 있음을 입증하였다.

• Toxicological Research
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• 제13권4호
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• pp.401-408
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• 1997

Adult male ICR mice were exposed to methylmercuric chloride (CH$_3$HgCI) through drinking water for 80 days. The distribution of mercury in the kidney, liver, spleen and cerebellum of the mouse was examined according to a autometallographic silver-enhancement technique based on a physical development process which renders mercury deposit visible. Grains of mercury traces were located in the proximal convoluted tubules. Lesser staining of the grains was seen in the collecting tubules of medulla. The glomerular basement membrane was void. In the liver, mercury accumulations were present primarily in the hepatocytes around portal area containing interlobular bile duct, artery and portal vein. Also grains of mercury traces were accumulated in the white pulp of the spleen and Purkinje cell layer of the cerebellum.