• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.245.2-245.2
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• 2013

Solution processed organic photovoltaic devices have relatively less attention compared to polymer photovoltaic devices even though they have high possibility to be developed because they have both advantages of polymer and organic, such as solution processable, no synthetic batch dependence of photovoltaic performance, high purity and high charge carrier mobility as well as relatively high efficiency (~7%). In addition, solution processed organic photovoltaic devices have an advantage of easiness to study the relationship between the molecular structure and photovoltaic performance due to its simple structure. In this work, five isoindigo based low band gap donor-acceptor-donor (D-A-D) small molecules with different electron donating strength were synthesized for investigating the relationship between the molecular structure and photovoltaic performance, especially, investigating the effects of different electron donating effect of donor group in isoindigo backbone to photovoltaic device performance. The variation of electron donating strength of donor group strongly affected the optical, thermal, electrochemical and photovoltaic device performances of isoindigo organic materials. The highest power conversion efficiency of ~3.2% was realized in bulk heterojuction photovoltaic device consisted of the ID3T as donor and PC70BM as acceptor. This work demonstrates the great potential of isoindigo moieties as electron deficient units as well as guideline for synthesis of donor-acceptor-donor (D-A-D) small molecules for realizing highly efficient solution processed organic photovoltaic devices.

• Korean Journal of Materials Research
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• v.33 no.6
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• pp.236-241
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• 2023

Solar cells based on p-conjugated donor-acceptor (D-A) organic molecular systems are a promising alternative to conventional electrical energy generation. D-A molecular systems, which have a triphenylamine (TPA) moiety linked with a benzothiadiazole (BTD) moiety, open the potential development of new small molecule donors for bulk heterojunction (BHJ) solar cells. Here, a series of donor-acceptor-π-acceptor (D-A-π-A) small molecule donors (SMD) derived from triphenylamine (TPA) donor and benzothiadiazole (BTD) acceptor building blocks, were designed for BHJ organic solar cells. The small molecule donors SMD1-4 were studied using density functional theory (DFT) and time dependent-DFT (TDDFT) methods, to understand the effect of cyano and fluorine group functionalization on their properties. The effect of structure alteration by cyano and fluorine group functionalization on the optoelectronic properties, the calculated highest occupied molecular orbitals (HOMOs) and lowest unoccupied molecular orbitals (LUMOs) and the HOMO-LUMO gaps were theoretically explored. The V_oc (open-circuit photovoltage) and fill factor (FF) for SMD1-4 were obtained with a PC₇₁BM acceptor, which showed that these organic small molecules are potential small molecule donors for organic bulk heterojunction solar cells.

• Journal of environmental and Sanitary engineering
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• v.13 no.2
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• pp.95-105
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• 1998

This research was investigated which denitrification of wastewater containing nitrate, using upflow anaerobic sludge blanket process. The upflow anaerobic sludge blanket process is also used for both artifical and industrial wastewater. Main ingredients investigated in the artifical and industrial wastewater experiment were the determination of optimum organism/nitrate ratios, nitrate removal efficiency by various hydrogen donor addition and characteristics of granular sludge and gas production in case of various hydrogen donor addition. From the experimental results the following conclusions were made: In case of adding methanol, ethanol and sodium acetate as hydrogen donor granular sludge was formed 50 days after seeding. Average diameter of granular sludge was 4.0 mm and settling velocity was 37 cm/min. Production rate of gas 3.3 L/d in case of adding methanol as hydrogen donor in wastewater containing 150mg/L nitrate. However adding ethanol and sodium acetate as hydrogen donor, gas production rate were 2.2-2.7L/d respectively. In case of adding methanol as hydrogen donor treatability of artifical wastewater contained 150mg/L as nitrate was about 93%. But in addition of sodium acetate in wastewater contained 40mg.L as nitrate, nitrate removal efficiency was 80%.

• Genomics & Informatics
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• v.15 no.1
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• pp.2-10
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• 2017

Early detection and proper management of kidney rejection are crucial for the long-term health of a transplant recipient. Recipients are normally monitored by serum creatinine measurement and sometimes with graft biopsies. Donor-derived cell-free deoxyribonucleic acid (cfDNA) in the recipient's plasma and/or urine may be a better indicator of acute rejection. We evaluated digital PCR (dPCR) as a system for monitoring graft status using single nucleotide polymorphism (SNP)-based detection of donor DNA in plasma or urine. We compared the detection abilities of the QX200, RainDrop, and QuantStudio 3D dPCR systems. The QX200 was the most accurate and sensitive. Plasma and/or urine samples were isolated from 34 kidney recipients at multiple time points after transplantation, and analyzed by dPCR using the QX200. We found that donor DNA was almost undetectable in plasma DNA samples, whereas a high percentage of donor DNA was measured in urine DNA samples, indicating that urine is a good source of cfDNA for patient monitoring. We found that at least 24% of the highly polymorphic SNPs used to identify individuals could also identify donor cfDNA in transplant patient samples. Our results further showed that autosomal, sex-specific, and mitochondrial SNPs were suitable markers for identifying donor cfDNA. Finally, we found that donor-derived cfDNA measurement by dPCR was not sufficient to predict a patient's clinical condition. Our results indicate that donor-derived cfDNA is not an accurate predictor of kidney status in kidney transplant patients.

• Polymer(Korea)
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• v.31 no.2
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• pp.136-140
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• 2007

Charge transfer interaction as a hybridization mechanism of silsesquioxane/polymer was tested using carbazole (electron donor) group and dinitrobenzene (electron acceptor) group. Hybridization test was conducted using films made from mixing/casting of poly (carbazole-styrene) (PS/D) and dimtrobenzyl silsesquioxane (Cube/A), and transparent hybrid films were successfully obtained under some conditions. $^1H-NMR$ of PS/D and Cube/A, and W absorption test of hybrid films showed that one acceptor and one donor can form one charge transfer complex when no silsesquioxane molecule was included in films, but transparent hybrids with no phase separation were obtained only at acceptor/donor ratios less than 0.7 : 1. These results also suggested that on average 4 charge transfer complexes form per one silsesquioxane.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.12
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• pp.992-995
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• 2011

The optical properties of ZnO thin film, being treated by O-plasma, have been studied using Photoluminescence(PL) spectroscopy with the change of temperature from 10 K to 290 K. Two characteristic peaks were identified at 10 K : 3.357 eV($D^{\circ}X$) and 3.324 eV(TES). The peak of $D^{\circ}X$ is believed to be due to neutral donor bound excitons where the donor is in the ground state. However, the TES(Two Electron Satellite) peak indicates the excited state of the donor(excitation energy was ~30 meV). The donor binding energy was estimated to be 44 meV, which indicates the possible presence of the neutral donor bound excitons at RT. The thermal effect including thermal broadening was identified from temperature evolution of the spectrum. Both the peak intensity and the peak energy have decreased as the temperature increases. As the temperature approaches to RT, the two peak merges into one broad peak, which is considered a combination of multiple peaks having different physical origins.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.4
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• pp.359-365
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• 2022

The development of efficient electron donor (or hole-transporting) molecules that can be used in various optoelectronic device fields is highly demanded. In this work, a novel class of triptycene-based three-dimensional (3D) triphenylamine (TI-TPA) derivatives with different end substituents was designed and prepared for transparent electron donor materials. Owing to the rigid 3D triptycene framework, the obtained TI-TPA derivatives had an amorphous morphology with high thermal decomposition temperature. The oxidation potential of these TI-TPA derivatives decreased as the electron donating strength of the end substituent increased. Among TI-TPA derivatives, TI-TPA-OMe exhibited the highest HOMO level (-5.31 eV) which is similar to that of Spiro-OMeTAD (-5.22 eV). In addition, TI-TPA-OMe was found to form a strong charge transfer complex with the triptycene-based acceptor TI-BQ, leading to a new absorption band at around 640 nm. These results can be applied for developing efficient electron donor materials that can mimic the advantages of the spiro-linked structure and TPA units of Spiro-OMeTAD.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.392.1-392.1
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• 2014

Isoindigo based small molecules have attracted much attention in the field of optoelectronic devices due to their broad absorbance and high charge carrier mobilitiies. Herein, we investigate the field effect transistor characteristics of a series of isoindigo based donor-acceptor-donor (D-A-D) small molecules containing a variable number of thiophene moieties (named IDT, ID2T, and ID3T) which form pi-bridges between the D and A moieites and a different donor moiety (IDED). In order to improve the carrier mobility, 1-chloronaphthalene (CN) and 1,8-diiodooctane (DIO) as solvent additives were used. The film morphology, crystallinity and optical properties of the materials processed with various concentrations of solvent additives were investigated through atomic force microscopy (AFM), X-ray diffraction (XRD) and UV-vis absorption spectroscopy.

• Journal of Biomedical Engineering Research
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• v.43 no.6
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• pp.434-440
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• 2022

Liver transplantation is a critical used treatment method for patients with end-stage liver disease. The number of cases of living donor liver transplantation is increasing due to the imbalance in needs and supplies for brain-dead organ donation. As a result, the importance of the accuracy of the donor's suitability evaluation is also increasing rapidly. To measure the donor's liver volume accurately is the most important, that is absolutely necessary for the recipient's postoperative progress and the donor's safety. Therefore, we propose liver segmentation in abdominal CT images from pre-operation, POD 7, and POD 63 with a two-dimensional U-Net. In addition, we introduce an algorithm to measure the volume of the segmented liver and measure the hepatectomy rate and regeneration rate of pre-operation, POD 7, and POD 63. The performance for the learning model shows the best results in the images from pre-operation. Each dataset from pre-operation, POD 7, and POD 63 has the DSC of 94.55 ± 9.24%, 88.40 ± 18.01%, and 90.64 ± 14.35%. The mean of the measured liver volumes by trained model are 1423.44 ± 270.17 ml in pre-operation, 842.99 ± 190.95 ml in POD 7, and 1048.32 ± 201.02 ml in POD 63. The donor's hepatectomy rate is an average of 39.68 ± 13.06%, and the regeneration rate in POD 63 is an average of 14.78 ± 14.07%.

• Journal of Magnetics
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• v.19 no.3
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• pp.261-265
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• 2014

Three-dimensional computed tomography is an effective tool to estimate the liver volume of living donors for the live liver transplantation. When additional operation is required, magnetic resonance imaging is conducted to determine the safety of the donor. This study compared the accuracy of magnetic resonance imaging and computed tomography in estimating 3D liver volume of 23 male and 7 female donors who underwent both magnetic resonance imaging and computed tomography tests before the transplantation. The analysis was conducted to see whether the liver's estimated total volumes and the left lobe volumes obtained from 3D-magnetic resonance imaging and 3D-computed tomography were identical. Volumes of the right lobe estimated with 3D-magnetic resonance imaging and 3D-computed tomography were compared with the actual volume of the right lobe harvested in the operating room because the volume of the right lobe is an important determinant in the safety of the donor. The total volume of the liver estimated from 3D-magnetic resonance imaging and 3D-computed tomography differed (1238.1904 units and 1402.364 units respectively). The left lobe volume of the liver estimated with 3D-magnetic resonance imaging and 3D-computed tomography also differed (450.530 units and 554.490 units, respectively). The right lobe volume of the liver estimated with 3D-magnetic resonance imaging and 3D-computed tomography were 787.660 units and 847.545 units, respectively, while the actual average right lobe volume of the harvested liver was 678.636 units. 3D-computed tomography has been widely used to estimate the right lobe volume of the donors' liver. However, 3D-magnetic resonance imaging was also very effective in estimating the volume of the liver. Thus, 3D-magnetic resonance imaging is also expected to become an important tool in determining the safety of the donors before transplantation.