• Bulletin of the Korean Chemical Society
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• v.25 no.12
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• pp.1833-1839
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• 2004

Recently mass spectrometry and separation methods such as liquid chromatography have become major tools in the field of proteomics. In this report, we describe in detail our efforts to develop ultra-high pressure capillary reverse-phase liquid chromatography (cRPLC) and its online coupling to a mass spectrometer by a nanoelectrospray (nanoESI) interface. The RPLC system is constructed in house to deliver LC solvents at the pressure up to 20,000 psig, which is four times higher than conventional RPLC systems. The high operation pressure allows the efficient use of packed micro-capillary columns (50, 75 and 150 ${\mu}$m i.d., up to 1.5 m long). We will discuss the effect of column diameter on the sensitivity of cRPLC/MS/MS experiments and the utility of the developed technique for proteome analysis by its application in the analysis of proteome samples having different levels of complexity.

• Mass Spectrometry Letters
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• v.2 no.2
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• pp.41-44
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• 2011

Molecular compositions of two types of heavy oil were studied using positive atmospheric pressure photoionization (APPI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Vacuum gas oil (VGO) was generated from vacuum distillation of atmospheric residual oil (AR), and slurry oil (SLO) was generated from catalytic cracking of AR. These heavy oils have similar boiling point ranges in the range of 210-$650^{\circ}C$, but they showed different mass ranges and double-bond equivalent (DBE) distributions. Using DBE and carbon number distributions, aromatic ring distributions, and the extent of alkyl side chains were estimated. In addition to the main aromatic hydrocarbon compounds, those containing sulfur, nitrogen, and oxygen heteroatoms were identified using simple sample preparation and ultra-high mass resolution FT-ICR MS analysis. VGO is primarily composed of mono- and di-aromatic hydrocarbons as well as sulfur-containing hydrocarbons, whereas SLO contained mainly polyaromatic hydrocarbons and sulfur-containing hydrocarbons. Both heavy oils contain polyaromatic nitrogen components. SLO inludes shorter aromatic alkyl side chains than VGO. This study demonstrates that APPI FT-ICR MS is useful for molecular composition characterization of petroleum heavy oils obtained from different refining processes.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.487-488
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• 2015

In type Ia supernovae (SNe Ia) cosmology, a well-established correlation exists between the mass of host galaxies and the Hubble residual (HR) of SNe Ia. In order to investigate the origin of this correlation, we used low-resolution spectroscopic data of early-type host galaxies obtained from our YOnsei Nearby Supernovae Evolution Investigation (YONSEI) project. We measured velocity dispersions and Lick/IDS absorption line indices from these fully calibrated spectra. These indices were used to estimate the luminosity-weighted mean age, metallicity and mass of host galaxies. We found a tight correlation between host mass and population age, which is consistent with the "downsizing" trend in early-type galaxies. This suggests that the well-established correlation between HR and host mass is most likely due to the difference in population age. More observations, which are in progress, are required to understand the impact of luminosity evolution on SNe Ia cosmology.

• Mass Spectrometry Letters
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• v.7 no.1
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• pp.26-29
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• 2016

Simultaneous determination of three corticosteroids (clobetasol propionate, betamethasone dipropionate, fluticasone propionate) in moisturizers was performed by using liquid chromatography (LC) coupled with tandem mass spectrometry (MS/MS). Sample preparation was conducted by the liquid-liquid extraction (LLE). Moisturizers include emulsifying agent and it forms micelles. In order to improve the extraction efficiency of corticosteroids trapped in micelle, newly developed-optimized extraction conditions which can remove the matrix effect from moisturizers was applied with various pH conditions in LLE extraction stage of sample preparation. Thus, the addition of 10 μL of 1 M HCl into moisturizers sample before extraction could improve the extraction efficiency. For the quantitative analysis, SRM table that contained specific transition of all of target corticosteroids was created. The developed method was validated for linearity, accuracy, precision, limit of detection (LOD), limit of quantization (LOQ) and recovery. Over the 0.99 r² value was obtained in calibration standard range. Effective accuracy and precision were also obtained. LODs were below 31 ng/mL and LOQs were estimated below 94 ng/mL for all corticosteroids tested.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.2
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• pp.47.1-47.1
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• 2015

The formation mechanism of supermassive black holes (SMBHs) at the center of galaxies remains an open fundamental question. Black holes (BHs) are believed to grow by accretion of gas or by merging with other BHs. Motivated by the observation of luminous quasar around redshift z ~ 7 with SMBH mass up to 109 solar mass, we follow the growth of the early assembly of SMBHs that trace the hierarchical evolution of dark matter halos derived from large cosmological simulations. The initial masses of BH seeds in the first halos were set up according to the BH mass - halo mass relation. We assume that mergers of host galaxies cause loss of angular momentum of gas and trigger episodes of gas accretion onto BHs for available durations and at the end of each episode of accretion, BHs merge immediately. We trace the evolution of BH masses for various scenarios for central gas properties in halos. We estimate the BH to halo mass ratio and BH mass function at each redshift.

• International Journal of Naval Architecture and Ocean Engineering
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• v.12 no.1
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• pp.957-966
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• 2020

This paper presents the virtual mass method to implement the prediction of total resistance for ice-going ship in floe ice region based on the combined method of CFD and DEM. Two ways of floe ice distribution are adopted for the analysis and comparison. The synthetic ice model test has been conducted to determine the optimal virtual mass coefficients for the two different floe ice distributions. Moreover, the further verification and prediction are developed in different ice conditions. The results show that, the fixed and random distributions in numerical method can simulate the interaction of ship and ice vividly, the trend of total resistance varying with the speed and ice concentration obtained by the numerical simulation is consistent with the model test. The random distribution of floe ice has higher similarity and better accuracy than fixed distribution.

• International Journal of Air-Conditioning and Refrigeration
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• v.10 no.4
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• pp.211-219
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• 2002

In this study, in-situ performance test of a wet surface finned-tube evaporator of an air source heat pump which has a rating capacity of 20 RT is carried out. Since test conditions, such as indoor and outdoor air conditions cannot be controlled to satisfy the standard test conditions, experiments are done with the inlet air conditions as they exist. From the experimental data, air side heat and mass transfer coefficients were calculated by the well known heat and mass transfer analogy and tube-by-tube method. Since current procedure underpredicted the experimental sensible heat factor (SHF), a proper empirical parameter was introduced to predict the experimental data with satisfactory results. This study provides the method of evaluating the heat and mass transfer coefficients of a wet surface finned-tube evaporator of which in-situ performance test is necessary.

• Bioinformatics and Biosystems
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• v.1 no.2
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• pp.89-94
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• 2006

Mass spectrometry (MS) is widely applied for high throughput proteomics analysis. When large-scale proteome analysis experiments are performed, it generates massive amount of data. To search these proteomics data against protein databases, fully automated database search algorithms, such as Mascot and SEQUEST are routinely employed. At present, it is critical to reduce false positives and false negatives during such analysis. In this review we have focused on aspects of automated protein identification using tandem mass spectrometry (MS/MS) spectra and validation of the protein identifications of two most common automated protein identification algorithms Mascot and SEQUEST.

• Advances in pediatric surgery
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• v.2 no.2
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• pp.138-142
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• 1996

Pulmonary sequestration is a complex anomaly involving the pulmonary parenchymal tissue and its vasculature. It presents as a cystic mass of nonfunctional lung tissue without communication with the tracheobronchial system. Usually, it receives blood supply from anomalous systemic vessels. Therefore, preoperative diagnosis of the pulmonary sequestration is difficult, especially when it is located in the abdomen and combined with congenital cystic adenomatoid malformation(CCAM). We encountered such a mass(CCAM type 2) detected prenatally by ultrasonography. It was a kidney bean shaped, pinkish mass straddling the thorax and abdomen on the right side. Because of the sonographic appearance, neuroblastoma was diagnosed preoperatively. The mass was completely extirpated without difficulty.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.639-644
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• 2009

This study presents the new idea of liquid desiccant system with extended surface to reduce the system size. The extended surface is inserted between vertical cooling/heating tubes to increase the mass transfer area, and the liquid desiccant flows through the tube wall and the extended surface. Mathematical models for heat and mass transfer between liquid desiccant and air stream at tube wall and extended surface are provided. Dimensionless design parameters governing heat and mass transfer phenomena around the tube and the extended surface are identifier, and dimensionless operating parameters depicting system operating condition including flow rate ratio between dehumidification/regeneration processes, and mass flow rate ratio between air stream and liquid desiccant are explained. The effects of the parameters on system performance are summarized.