• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 춘계학술대회
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• pp.387-390
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• 2006

We report here that under strong attacksof external $CH_4$ guest molecules the sII and sH methane hydrates are structurally transformed to the crystalline me framework of sI, leading to favorable change of the lattice dimension of the host-guest networks. The High Power Decoupling $^{13}C$ NMR and Raman spectroscopies were used to identify structure transitions of the mixed $CH_4+C_2H_6$ hydrates (sIIl) and hydrocarbons (methylcyclohexane, isopentane) + $CH_4$ hydrates (sH). The resulting spectra indicate that most of the synthesized sII and sH hydrates were transformed to methane hydrate of sl under 110 bar and particularly the coexistence of sl with sII or sH appear according to the surrounding methane-rich gas conditions. The present findings might be expected to Provide rational evidences regarding the preponderant occurrence of naturally-occurring sI methane hydrates in marine sediments.

• 분석과학
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• 제21권6호
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• pp.562-568
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• 2008

A novel two-dimensional cadmium(II)-nickel(II) bimetallic host clathrate, $[Cd{NH_2CH_2CH_2OH}_2Ni(CN)_4]{\cdot}3C_6H_5NH_2{\cdot}H_2O$, 1, has been synthesized and structurally characterized by X-ray single crystallographic method. The clathrate 1 crystallizes in the monoclinic system, space group $P2_1/c$ with a = 14.370(3), b = 7.728(1), c = 28.172(4) ${\AA}$, ${\beta}=97.58(1)^{\circ}$, V = 3101.1(9) ${\AA}^3$, Z = 4. The host framework of the clathrate 1 is built of the cyanide bridges between octahedral Cd(II) atom and square planar Ni(II) atom. The octahedral Cd atoms ligated by two 2-aminoethanol molecules and four cyanide ligands bridged with square planar Ni atoms. The Ni atoms bridges to four Cd atoms via cyanides is made up of puckered quadrangles of composition $\{CdNi(CN)_2\}_2$, all edges are shared. This cyanide bridges form an infinite two-dimensional host networks stacking along b axis. 2-Aminoethanol ligands bond to Cd atom through N atom as a monodentate ligand in the axial position and four cyanides take an equatorial plane with all in trans-configurations. The aniline guest molecules and water molecules are located in between the host layer sheets, respectively.

• Bulletin of the Korean Chemical Society
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• 제29권12호
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• pp.2383-2389
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• 2008

• Journal of Pharmaceutical Investigation
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• 제21권4호
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• pp.223-230
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• 1991

The structural specificity and the chemical dynamics between ${\beta}-cyclodextrin$ and aspirin were studied by FT-IR UN, $^1H$ NMR. $^{13}C NMR$. and FAB-MS spectroscopy in solution and solid state, A stable solid inclusion complex was prepared by the recrystallization method, From the spectral changes of the host and guest molecules, orientational preference for binding in the cyclodextrin cavity was determined.

• Korean Chemical Engineering Research
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• 제55권5호
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• pp.704-710
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• 2017

가스 하이드레이트 형성원리를 이용한 해수담수화는 이미 상용화된 역삼투 방식에 비하여 아직 실증화 단계이지만 그 공정이 비교적 단순하고 특히 냉매를 객체가스로 사용할 경우 아주 낮은 공정 온도가 필요하지 않아 에너지 소비량(thermal budget)이 향상될 가능성이 있기 때문에 여전히 많은 관심을 받고 있다. 따라서 본 연구에서는 수소불화탄소(HFC, hydrofluorocarbon) 및 수소염화불화탄소(HCFC, hydrochlorofluorocarbon) 계열의 냉매들을 객체가스로 한 가스 하이드레이트 형성 거동을 에너지적인 관점에서 해석하고자 하였고 이를 위해 밀도 범함수(DFT, density functional method) 이론을 기반으로 한 분자모델링을 도입하였다. 객체가스(guest gas)로 R-134a, R-227ea, R-236fa, R-141b를 선정하였으며 계산을 위하여 물 분자로 이루어진 $5^{12}$, $5^{12}6^2$, $5^{12}6^4$의 세가지 구조의 동공들(cavities)을 구성하였다. 동공, 객체가스, 그리고 객체가스가 삽입된 동공의 구조를 분자모델링을 이용하여 각각 최적화하였고 계산된 각 구조의 에너지로부터 동공과 객체가스의 결합에너지(binding energy)를 계산하였다. 마지막으로 결합에너지를 비교함으로써 어느 냉매가 가장 유리한 조건에서 가스하이드레이트를 형성할 지를 판단하였다. 결과적으로 R-236fa가 가장 자발적(spontaneous)으로 가스 하이드레이트를 형성할 것으로 예상되었고 사람에 대한 낮은 독성과 물에 대한 작은 용해도 측면에서도 가장 적절한 선택으로 평가되었다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.146.2-146.2
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• 2011

Molecular behaviors and crystal structures of the binary hydrates of $CH_4$ and ethanol were identified by means of 13C solid-state NMR and powder XRD methods at various concentrations of ethanol. In addition, NMR peak areas were used to calculate cage occupancies for both guest species. Obtained results showed that more $CH_4$ molecules are captured into hydrate phase per unit mass of ethanol molecules because $CH_4$ molecule can occupy sII large cages more, and pure $CH_4$ hydrate can form more as well at lower ethanol concentrations. Even though tuning phenomenon was already reported for some aqueous hydrate promoters such as THF, aqueous ethanol solutions are found to play the same tuning role in the binary clathrate hydrates in this study.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.519-523
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• 2007

Gas(or methane) hydrates are solid solutions when water molecules are linked through hydrogen bonding and create host lattice cavities that can enclose a large variety of guest gas molecules. The natural gas hydrate crystal may exist at low temperature above the normal freezing point of water and high pressure greater than about 30 bars. A lot of quantities of natural gas hydrates exists in the earth and many production schemes are being studied. In the present investigation, depressurization method was considered to predict the production of gas and the simulation of the two phase flow - gas and water - in porous media is being carried out. The simulation show about the fluid flow in porous media have a variety of applications in industry. Results provide the appearance of gas and water production, the pressure profile, the saturation of gas/ water/ hydrates profiles and the location of the pressure front.

• 한국전기전자재료학회논문지
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• 제26권9호
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• pp.682-685
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• 2013

We have fabricated blue phosphorescent organic light-emitting devices (OLEDs) on a plastic substrate. The solution coated poly (9-vinylcarbazole) (PVK) host doped with Bis (3,5-difluoro-2-(2-pyridyl)phenyl_(2-carboxypyridyl)irdium(III) (FIrPic) guest molecules was used as an hole transporting emission layer. The device structure was ITO/PVK:FIrpic (50 nm, xwt%)/TAZ 50 nm)/LiF (0.5 nm)/Al (100 nm). The concentration of FIrpic molecule was varied from 1 wt% to 10 wt%. The OLED on plastic substrate exhibited maximum current efficiency of 18 cd/A with 5 wt% FIrpic molecules were doped into the PVK layer.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집B
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• pp.241-246
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• 2000

Gas hydrates are solid solutions when water molecules are linked through hydrogen bondin create host lattice cavities that can enclose a large variety of guest gas molecules. The natural hydrate crystal may exist at low temperature above the normal freezing point of water and pressure greater than about 30 bars. A lot of quantities of natural gas hydrates exists in the ear many production schemes are being studied. In the present investigation, depressurization method considered to predict the production of gas and the simulation of the two phase flow - gas and - in porous media is being carried out. The simulation show about the fluid flow in porous have a variety of applications in industry. Results provide the appearance of gas and water prod the pressure profile, the saturation of gas/ water/ hydrates profiles and the location of the pl front.

• 한국응용과학기술학회지
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• 제13권2호
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• pp.29-37
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• 1996

The phase separated structure and the electo-optical properties of the polymer /liquid crystal(LC) composite films including a dye were investigated. The phase separated structure of the polymer /LC / dye composite film(GH composite film) including below 2wt% dye against LC was almost same with the composite film which does not include dye. But the electro-optical properties of the GH composite film strongly depended on weight fraction of the dye against the LC. The response time of the GH composite film increased with the increase of the dissolved dye in LC because the dye acts as a registivity for the orientation of LC molecules by the electric filed.