• 한국분무공학회지
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• 제22권4호
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• pp.218-224
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• 2017

In order to improve the quality of air in urban areas, the emission regulations are being strengthened by the government. The on-road test of light-duty vehicles was started with PEMS because certification test mode does not sufficiently reflect on-road conditions. Therefore, The PEMS-based test was implemented from Sep. 2017 in Europe and Korea. However, this is lack of data on various on-road patterns in Korea. The purpose of the present study has analyzed the effect of speed per acceleration and acceleration on NOx emission on-road driving. The test route consisted of urban, rural, and motorway in Seoul. This study has been conducted by Euro-6 vehicles using on SCR system with PEMS. The on-road emission characteristics were evaluated by moving averaging windows (MAW) method. In results, RDE-NOx by severe driving pattern has been 1.4 times higher than soft driving pattern NIER Route 1.

• Bulletin of the Korean Chemical Society
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• 제30권10호
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• pp.2287-2293
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• 2009

Gas Chromatography-Mass Spectrometry (GC-MS) fingerprint analysis, Principle Components Analysis (PCA), and Hierarchical Cluster Analysis (HCA) were introduced for quality assessment of Curcuma longa L. (C. longa). The GC-MS fingerprint method was developed and validated by analyzing 33 batches of samples of C. longa from different geographic locations. 18 chromatographic peaks were selected as characteristic peaks and their relative peak areas (RPA) were calculated for quantitative expression. Two principal components (PCs) were extracted by PCA. C. longa collected from Guizhou and Fujian were separated from other samples by PC1, capturing 71.83% of variance. While, PC2 contributed for their further separation, capturing 11.13% of variance. HCA confirmed the result of PCA analysis. Therefore, GC-MS fingerprint study with chemometric techniques provides a very flexible and reliable method for quality assessment of C. longa.

• Bulletin of the Korean Chemical Society
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• 제35권10호
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• pp.3005-3008
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• 2014

Human ChlR1 protein (hChlR1), a member of the cohesion establishment factor family, plays an important role in the segregation of sister chromatids for maintenance of genome integrity. We previously reported that hChlR1 interacts with hFen1 and stimulates its nuclease activity on the flap-structured DNA substrate covered with RPA. To elucidate the relationship between hChlR1 and Okazaki fragment processing, the effect of hChlR1 on in vitro nuclease activities of hFen1 and hDna2 was examined. Independent of ATPase activity, hChlR1 stimulated endonuclease activity of hFen1 but not that of hDna2. Our findings suggest that the acceleration of Okazaki fragment processing near cohesions may aid in reducing the size of the replication machinery, thereby facilitating its entry through the cohesin ring.

• Elastomers and Composites
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• 제53권3호
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• pp.150-157
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• 2018

Fatigue properties of rubber are one of the most important characteristics in the rubber industry. In this study, the fatigue properties of MREs (magneto-rheological elastomers) based on NR (natural rubber), EPDM (ethylene-propylene diene monomer), and AEM (ethylene/acrylic elastomer) were investigated. For comparison, MREs with a Shore hardness of 60A were prepared. According to the relative results, the fatigue properties of EPDM MRE were the worst. Thus, we investigated methods to improve the fatigue properties of EPDM MRE by varying the carbon black content and curing systems of EPDM as the matrix of the MRE. Dynamic properties were measured using a fatigue tester and an RPA (rubber process analyzer), and the XPS (X-ray photoelectron spectroscopy) was used to analyze the curing system of the EPDM matrix. According to the results, the Payne effect increased and the fatigue resistance decreased as the carbon black content increased. In case of the curing system, the CV (conventional vulcanization) system was superior to the EV (efficient vulcanization) system in terms of the fatigue resistance. This was because the number of flexible bonds in the case of the CV system was higher than that in the case of the EV system. However, the EV system showed excellent mechanical properties because it had many monosulfidic bonds with strong binding energy.

• 한국정보처리학회논문지
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• 제6권7호
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• pp.1849-1857
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• 1999

메모리 기반 추론에서 기억공간의 효율적인 사용과 분류성능의 향상을 위하여, 재귀 분할 평균 기법을 제안하였다. 이 알고리즘은 패턴공간을 구성하는 각 초월 평면이 동일한 클래스소속으로 패턴으로 구성될 때까지 재귀적으로 분할한 후, 초월 평면별로 소속된 패턴들의 평균값을 계산하여 대표패턴을 추출한다. 또한 각 특징과 클래스간의 상호정보를 특징의 가중치로 사용하여 분류 성능의 향상을 시도하였다. 제안된 알고리즘은 k-NN(k-Nearest Neighbors) 분류기에서 필요로 하는 메모리 공간의 30~90%만을 사용하며, 분류에 있어서도 k-NN과 유사한 인식 성능을 보이고 있다. 또한 저장된 패턴 개수의 감소로 인하여, 실제 분류에 소요되는 시간에 있어서도 k-NN보다 월등히 우수한 성능을 보이고 있다.

• Nuclear Engineering and Technology
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• 제51권4호
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• pp.1176-1179
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• 2019

Measurements of activity concentrations of radionuclides in atmospheric releases were performed in 2017-2018 at vent stacks of seven Russian nuclear power plants. The selected instruments and research methods, with detection limits significantly lower than the existing detection limit of Russian NPPs routine control, allowed to reliably determine up to 26 radionuclides. Analysis of experimental data allows to determine the list of radionuclides for calculation the effective dose rates to public and the permissible annual discharge levels for each Russian NPP. Radiocarbon is determined as major contributor for the dose from the atmospheric releases of LWGR reactors - up to 98% for EGP-6 and RBMK-1000 (Smolensk NPP) reactors. For PWR reactors (VVER) radionuclides contribution to the annual dose from atmospheric releases is more complicated, but, in general, dose is formed by tritium, $^{14}C$ and noble gases. The special monitoring results with ranking of measured radionuclides according to their contribution to the effective dose makes it possible to optimize the list of controlled radionuclides in airborne releases of Russian NPPs from 94 to 8-16 for different NPPs.

• Molecules and Cells
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• 제42권7호
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• pp.546-556
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• 2019

Protein phosphatase 4 (PP4) is a crucial protein complex that plays an important role in DNA damage response (DDR), including DNA repair, cell cycle arrest and apoptosis. Despite the significance of PP4, the mechanism by which PP4 is regulated remains to be elucidated. Here, we identified a novel PP4 inhibitor, protein phosphatase 4 inhibitory protein (PP4IP) and elucidated its cellular functions. PP4IP-knockout cells were generated using the CRISPR/Cas9 system, and the phosphorylation status of PP4 substrates (H2AX, KAP1, and RPA2) was analyzed. Then we investigated that how PP4IP affects the cellular functions of PP4 by immunoprecipitation, immunofluorescence, and DNA double-strand break (DSB) repair assays. PP4IP interacts with PP4 complex, which is affected by DNA damage and cell cycle progression and decreases the dephosphorylational activity of PP4. Both overexpression and depletion of PP4IP impairs DSB repairs and sensitizes cells to genotoxic stress, suggesting timely inhibition of PP4 to be indispensable for cells in responding to DNA damage. Our results identify a novel inhibitor of PP4 that inhibits PP4-mediated cellular functions and establish the physiological importance of this regulation. In addition, PP4IP might be developed as potential therapeutic reagents for targeting tumors particularly with high level of PP4C expression.

• Elastomers and Composites
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• 제54권1호
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• pp.22-29
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• 2019

Chitosan-polyvinyl alcohol (PVA) -bamboo charcoal/silica (CS-PVA-BC/SI) hybrid fillers with compatibilized styrene-butadiene rubber (SBR) composites were fabricated by the interpenetrating polymer network (IPN) method. The structure and composition of the composite samples were characterized by scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FT-IR). The viscoelastic behaviors of the rubber composites and their vulcanizates were explored using a rubber processing analyzer (RPA) in the rheometer, strain sweep and temperature sweep modes. The storage and loss moduli of SBR increased significantly with the incorporation of different hybrid fillers, which was attributed to the formation of an interphase between the hybrid fillers and rubber matrix, and the effective dispersion of the hybrid fillers. The mechanical properties (hardness, tensile strength, oxygen transmission rate, and swelling rate) of the composite samples were characterized in detail. From the results of the mechanical test, it was found that BC-CS-PVA0SBR had the best mechanical properties. Therefore, the BC-CS-PVA hybrid filler provided the best reinforcement effects for the SBR latex in this research.

• Elastomers and Composites
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• 제53권4호
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• pp.202-206
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• 2018

Five solution styrene butadiene rubber/neodymium butadiene rubber (SSBR/NdBR) composites were manufactured using different ratios of SSBR and NdBR. In this study, the composites were reinforced with NdBR and silica to confirm the physical properties of SSBR used for treads of automobile tires and the dispersibility with silica. The morphologies of the rubber composites were observed using field-emission scanning electron microscopy (FE-SEM). The crosslinking behaviors of the composites were tested using a rubber process analyzer (RPA), and the abrasion resistances were tested using a National Bureau of Standards (NBS) abrasion tester. The hardness values, tensile strengths, and cold resistances of the composites were also tested according to ASTM standards. Increased NdBR content yielded composites with excellent crosslinking properties, abrasion resistances, hardnesses, tensile strengths, and cold resistances. The crosslinking point increased due to the double bond in NdBR, thereby increasing the degree of crosslinking in the composites. The NdBR-reinforced composites exhibited excellent abrasion resistances, which is explained as follows. In SSBR, a breakage is permanent because a resonance structure between styrene and SSBR forms when the molecular backbone is broken during the abrasion process. However, NdBR forms an additional crosslink due to the breakdown of the molecular backbone and high reactivity of the radicals produced. In addition, the low glass transition temperature (Tg) of NdBR provided the rubber composites with excellent cold resistances.

• 한국재료학회지
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• 제34권2호
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• pp.63-71
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• 2024

Slipchip offers advantages such as high-throughout, low cost, and simple operation, and therefore, it is one of the technologies with the greatest potential for high-throughput, single-cell, and single-molecule analyses. Slipchip devices have achieved remarkable advances over the past decades, with its simplified molecular diagnostics gaining particular attention, especially during the COVID-19 pandemic and in various infectious diseases scenarios. Medical testing based on nucleic acid amplification in the Slipchip has become a promising alternative simple and rapid diagnostic tool in field situations. Herein, we present a comprehensive review of Slipchip device advances in molecular diagnostics, highlighting its use in digital recombinase polymerase amplification (RPA), loop-mediated isothermal amplification (LAMP), and polymerase chain reaction (PCR). Slipchip technology allows users to conduct reliable droplet transfers with high-throughput potential for single-cell and molecule analyses. This review explores the device's versatility in miniaturized and rapid molecular diagnostics. A complete Slipchip device can be operated without special equipment or skilled handling, and provides high-throughput results in minimum settings. This review focuses on recent developments and Slipchip device challenges that need to be addressed for further advancements in microfluidics technology.