• 대한기계학회논문집B
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• 제35권11호
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• pp.1177-1184
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• 2011

GTS 기술은 천연가스 하이드레이트 생산, 해양수송 및 재기화의 3 단계로 구성되며, 대규모 재기화 플랜트의 효율적 운용을 위해서는 하이드레이트 펠릿의 재기화에 필요한 열수 온도와 유량의 정확한 예측이 필수적이다. 하이드레이트 펠릿이 열수에서 해리할 때 펠릿 표면에서 분출되는 가스는 주변 유동장과 열전달 특성에 영향을 미칠 것이며 본 실험에서는 가압된 용기내의 중저온 열수에서 해리하는 메탄가스 하이드레이트 펠릿의 용해특성을 연구하였다. 해리과정 중 변화하는 펠릿 형상을 관찰하고 해리 완료시간을 측정함으로써 하이드레이트 전환율, 열수 온도 및 유동속도가 해리에 미치는 영향을 파악하였으며, 펠릿 표면에서 분출되어 상승하는 메탄가스 기포류가 유발한 2 차유동이 열전달률을 증가시켜 해리 완료시간이 단축됨을 확인하였다.

• Bulletin of the Korean Chemical Society
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• 제33권10호
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• pp.3233-3240
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• 2012

We demonstrated the combined applications of online protein digestion using trypsin immobilized enzyme reactor (IMER) and dual tandem mass spectrometry with collisionally activated dissociation (CAD) and electron transfer dissociation (ETD) for tryptic peptides eluted through the trypsin-IMER. For the trypsin-IMER, the organic and inorganic hybrid monolithic material was used. By employing the trypsin-IMER, the long digestion time could be saved with little or no sacrifice of the digestion efficiency, which was demonstrated for standard protein samples. For three model proteins (cytochrome c, carbonic anhydrase, and bovine serum albumin), the tryptic peptides digested by the IMER were analyzed using LC-MS/MS with the dual application of CAD and ETD. As previously shown by others, the dual application of CAD and ETD increased the sequence coverage in comparison with CAD application only. In particular, ETD was very useful for the analysis of highly-protontated peptide cations, e.g., ${\geq}3+$. The combination approach provided the advantages of both trypsin-IMER and CAD/ETD dual tandem mass spectrometry applications, which are rapid digestion (i.e., 10 min), good digestion efficiency, online coupling of trypsin-IMER and liquid chromatography, and high sequence coverage.

• Mass Spectrometry Letters
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• 제2권1호
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• pp.24-27
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• 2011

Hyperthermal ion/surface collisions of bromotoluene radical cations were studied using perfluorinated (F-SAM) and hydroxyl-terminated (OH-SAM) self-assembled monolayer surfaces in a tandem mass spectrometer with BEEQ geometry. The isomers were differentiated by ion abundance ratios taken from surface-induced dissociation (SID). The dissociation rate followed the order of ortho > meta > para isomers. The peak abundance ratio of m/z 51 to m/z 65 showed the best result to discern the isomers. A dissociation channel leading to tolylium ion was suggested to be responsible for the pronounced isomeric differences. The capability of SID to provide high-energy activation with narrow internal energy distribution may have channeled the reaction into the specific dissociation pathway, also facilitating small differences in reaction rates to be effective in the spectral time window of this experiment. All of the molecular ions experiencing reactive collisions with the F-SAM surface undergo transhalogenation, in which a fluorine atom on the surface replaces the bromine in the incoming ions. This reactive collision was dependent on the laboratory collision energy occurring in ca. 40.75 eV range.

• Bulletin of the Korean Chemical Society
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• 제28권4호
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• pp.619-623
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• 2007

Synthesis of 4-substituted 3-exo-methylenechroman derivatives was carried out by the n-Bu3SnH-mediated vinyl radical cyclization as the key step starting from various salicylaldehydes.

• 한국동물생명공학회지
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• 제38권1호
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• pp.10-16
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• 2023

Intermuscular fat is essential for enhancing the flavor and texture of cultured meat. Mesenchymal stem cells derived from intermuscular adipose tissues are a source of intermuscular fat. Therefore, as a step towards developing a platform to derive intermuscular fat from mesenchymal stem cells (MSCs) for insertion between myofibrils in cultured beef, an advanced protocol of intermuscular adipose tissue dissociation effective to the isolation of MSCs from intermuscular adipose tissues was developed in cattle. To accomplish this, physical steps were added to the enzymatic dissociation of intermuscular adipose tissues, and the MSCs were established from primary cells dissociated with physical step-free and step-added enzymatic dissociation protocols. The application of a physical step (intensive shaking up) at 5 minutes intervals during enzymatic dissociation resulted in the greatest number of primary cells derived from intermuscular adipose tissues, showed effective formation of colony forming units-fibroblasts (CFU-Fs) from the retrieved primary cells, and generated MSCs with no increase in doubling time. Thus, this protocol will contribute to the stable supply of good quality adipose-derived mesenchymal stem cells (ADMSCs) as a fat source for the production of marbled cultured beef.

• 한국가스학회지
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• 제19권3호
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• pp.54-59
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• 2015

가스하이드레이트(GH: Gas Hydrate)는 전 세계적으로 약 10조 톤에 이르는 엄청난 양이 대부분 해양의 대륙사면에 부존되어 있으나(동토 지역 : 2 %, 해양 대륙사면 98 %), 현재까지 가스하이드레이트 저류층으로부터 상업화할 수 있을 만큼 가스를 회수하는 기술이 개발되어 있지 않은 실정이다. 일반적으로 회수하는 방법은 감압법, 열자극법, 억제재 주입법 및 치환법 등으로 크게 나누어 볼 수 있으며, 본 연구에서는 가스하이드레이트 포화율과 감압률에 따라서 가스하이드레이트 해리시간 및 가스생산이 어떻게 달라지는 지, 그에 대한 특성을 분석하고자 하였다. 연구분석 결과 감압률과 해리시간의 상관 관계식을 도출($Y=0.0004X^2-0.499X+176.86$)할 수 있었고, 또한 감압률이 클수록 메탄생산량이 좋다는 것을 알 수 있었지만(감압률 40% 대비 50%에서 메탄가스생산량이 46.2% 향상), 감압률이 60%에서는 오히려 생산량이 줄어드는데, 이는 가스하이드레이트 재형성에 기인한 것으로 판단된다.

• 신재생에너지
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• 제2권3호
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• pp.37-41
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• 2006

In this study, an experimental apparatus has been designed and set up to analyze the dissociating phenomena of hydrate in porous rock. Experiments with the depressurization scheme have been carried out to investigate the dissociation characteristics of methane hydrates and the productivities of dissociated gas and water. From the experiments, it has been provided a determination of volume of gas produced and the progress of the dissociation front, as a function of time when hydrate is depressurized. Also, it has been investigated the flowing behavior of the dissociated gas and water in porous rock and the efficiency of the production

• 산업기술연구
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• 제40권1호
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• pp.25-32
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• 2020

In this study, the effects of thermodynamic hydrate inhibitors on hydrate formation and dissociation behaviors were identified. The nucleation and growth of CP hydrate in the presence of methanol were monitored by optical microscope. Cyclopentane was used to demonstrate the oil phase in the pipeline in this study. Hydrate morphology, required time for hydrate formation, hydrate dissociation temperature were also identified by experiments. With the addition of methanol in water solution, the hydrate nucleation as well as hydrate growth were delayed. Moreover, hydrate morphology was also varied with the addition of methanol. Hydrate formation and dissociation temperature also decrease as the concentration of methanol increases.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 춘계학술대회
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• pp.412-414
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• 2006

In this study, an experimental apparatus has been designed and set up to analyze the dissociating phenomena of hydrate in porous rock. Experiments with the depressurization ion scheme have been carried out to investigate the dissociation characteristics of methane hydrates and the productivities of dissociated gas and water. From the experiments, it has been provided a determination of volume of gas produced and the progress of the dissociation front, as a function of time when hydrate is depressurized. Also, it has been investigated the flowing behavior of the dissociated gas and water in porous rock and the efficiency of the production

• Bulletin of the Korean Chemical Society
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• 제23권2호
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• pp.267-270
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• 2002

Photodissociations of o-, m-, and p-iodotoluene radical cations were investigated by using Fourier-transform ion cyclotron resonance (FT-ICR) spectrometry. Iodotoluene radical cations were prepared in an ICR cell by a photoionization charge-transfer method. The time-resolved one-photon dissociation spectra were obtained at 532 nm and the identities of $C_7H_7^+$ products were determined by examining their bimolecular reactivities toward toluene-$d_8$. The two-photon dissociation spectra were also recorded in the wavelength range 615-670 nm. The laser power dependence, the temporal variation, and the identities of $C_7H_7^+$ were examined at 640 nm. The mechanism of unimolecular dissociation of iodotoluene radical cations is elucidated: the lowest barrier rearrangement channel leads exclusively to the formation of the benzyl cation, whereas the direct C-I cleavage channel yields the tolyl cations that rearrange to both benzyl and tropylium cations with dissimilar branching ratios among o-, m-, and p-isomers. With a two-photon energy of 3.87 eV at 640 nm, the direct C-I cleavage channel results in the product branching ratio, [tropylium cation]/[benzyl cation], in descending order, 0.16 for meta >0.09 for ortho >0.05 for para.