• Design & Manufacturing
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• v.18 no.3
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• pp.15-21
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• 2024

This study investigates the causes of wrinkle defects in PA12-insulated busbars used in electric vehicles and proposes an improvement method to address these issues. Busbars, essential components for efficient current transmission in electric vehicle battery modules, require complex three-dimensional bending to optimize internal layouts. For this study, oxygen-free copper busbars with a 0.8 mm PA12 insulation coating were subjected to three types of bending tests: flat bending, edge bending, and torsional bending. Experimental results showed that wrinkle defects only occurred during edge bending, while flat and torsional bending modes exhibited no significant issues. Cross-sectional analysis revealed that the PA12 insulation layer's thickness was uneven, with thinner sections on flat areas and thicker accumulation at the comers. This uneven distribution led to poor adhesion between the insulation and copper layers, resulting in the formation of wrinkles, particularly in areas with air gaps ranging from 75 to 250 ㎛. To further analyze the issue, finite element analysis (FEA) of the bending process was performed under adhesive and non-adhesive conditions. The results confirmed that wrinkles formed when the adhesion between the copper and PA12 coating was insufficient. Improved adhesion conditions, achieved through a heat treatment process at 120℃ for 2 hours, significantly reduced the occurrence of wrinkles during edge bending. This study demonstrates that optimizing the adhesion between the insulation coating and the copper busbar, through controlled heat treatment, can prevent wrinkle defects. The findings provide a pathway for enhancing the durability and performance of insulated busbars in electric vehicle applications.

• Anatomy and Cell Biology
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• v.55 no.1
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• pp.92-99
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• 2022

The liver is the largest gland of the gastrointestinal tract having both exocrine and endocrine functions. Developmentally it arises as a ventral outgrowth from the gut endoderm during 3rd week of intrauterine life. The foetal liver is very important because of its synthetic and hemopoietic potential. The present work aimed to see the detailed histogenesis and development of the foetal liver by cytological, immunohistochemical and ultrastructural study. The liver tissue of nine aborted foetuses of various gestational age were studied. For cytology: special stains like Masson trichrome, periodic acid Schiff and reticulin were used, immunohistochemical staining was performed with triple antibodies (c-myc, Ki-67 and Ber-H2), and for ultrastructure: aluminium mounted specimens were coated with gold and argon gas and observed under scanning electron microscopy (EM). Cytology and immunohistochemistry showed the development of duct patterns and hemopoietic patterns in all stages of fetogenesis. The ductal plate was marked by the layer of dark brown staining cells at the edge of two portal tracts. The haemopoietic cells with sinusoids and aggregation of hepatocytes were observed in the early weeks of gestation. EM showed tree-like branching of a portal canal depicting hepatic segmentation of foetal liver. The organizational changes in lobular pattern, duct pattern, and microstructure of liver during fetogenesis are very crucial to achieve the adult morphology in feature. Histogenesis of the foetal liver follows a multistep process depending upon the gestational age, any deviation from normalcy may lead to structural and functional abnormality later in life.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.34 no.3
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• pp.157-165
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• 2008

In the previous study, the anti-oxidant activity of oxtract/fraction of Sueada aspparagoides(SA) and the stability test for the cream containing SA extract were investigated respectively[1,2]. In this study, the components of SA extract were analyzed by TLC, HPLC, and LC/ESI-MS/MS, $^1H$-NMR. TLC chromatogram of ethyl acetate fraction of SA extract revealed 5 bands $(SA1{\sim}SA5)$. HPLC chromatogram of aglycone fractions obtained from deglycoylation reaction of ethyl acetate fraction showed 2 bands (SAA 2 and SAA 1), which were identified as quercetin (composition ratio, 16.88%) and kaempferol (83.12%) in the order of elution time. Among 5 bands of TLC chromatogram, 4 bands $(SA2{\sim}SA5)$ also were Identified as kaempferol-3-O-glucoside (SA 2), quercetin-3-O-glucoside (SA3), kaempferol-3-O-rutinoside (SA 4), quercetin-3-O-rutinoside (SA 5) by LC/ESI-MS/MSMS/MS. respectively. The spectrum generated for SAA 1 by LC/ESI-MS/MS in the negative ion mode also gave the ion corresponding to the deprotonated aglycone $[M-H]^-$ (285m/z), the $^1H$-NMR spectrum contained signals [${\delta}$ 6.19 (1H, d, J=1.8Hz, H-6), ${\delta}$ 6.44 (1H, d, J=1.8Hz, H-8), ${\delta}$ 6.92 (2H, d, J=9.0Hz, H-3', 5'), ${\delta}$ 8.04 (2H, d, J=9.0Hz, H-2', 6', thus SAA 1 was identified as kaempferol. SAA 2 yielded the deprotonated agycone ion $[M-H]^-$ (301m/z), $^1H$-NMR spectrum showed signals [${\delta}$ 6.20 (1H, d, J=2.0Hz, H-6), ${\delta}$ 6.42 (1H, d, J=2.0Hz, H-8), ${\delta}$ 6.90 (1H, d, J=8.6Hz, H-5'), ${\delta}$ 7.55 (1H, dd, J=8.6, 2.2Hz, H-6'), ${\delta}$ 7.69 (1H, d, J=2.2Hz, H-2', thus SAA 2 was Identified as quercetin. In conclusion, with the anti-oxidant activity and the stability test reported previously, component analysis of SA extracts could be applicable to new cosmeceuticals.

• Korean Journal of Agricultural and Forest Meteorology
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• v.5 no.2
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• pp.61-69
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• 2003

Surface energy and $CO_2$ fluxes have been measured over a farmland in Haenam, Korea since July 2002. Eddy covariance technique, which is the only direct flux measurement method, was employed to quantitatively understand the interaction between the farmland ecosystem and the atmospheric boundary layer. Maintenance of eddy covariance system was the main concern during the early stage of measurement to minimize gaps and uncertainties in the dataset. Half-hourly averaged $CO_2$ concentration showed distinct diurnal and seasonal variations, which were closely related to changes in net ecosystem exchange (NEE) of $CO_2$. Daytime maximum $CO_2$ uptake was about -1.0 mg $CO_2$ m$^{-2}$ s$^{-1}$ in August whereas nighttime $CO_2$ release was up to 0.3 mg $CO_2$ m$^{-2}$ s$^{-1}$ during the summer. Both daytime $CO_2$ uptake and nighttime release decreased gradually with season. During the winter season, NEE was from near zero to 0.05 mg $CO_2$ m$^{-2}$ s$^{-1}$ . FK site was a moderate sink of atmospheric $CO_2$ until September with daily NEE of 22 g $CO_2$ m$^{-2}$ d$^{-1}$ . In October, it became a weak source of $CO_2$ with an emission rate of 2 g $CO_2$ m$^{-2}$ d$^{-1}$ . Long-term flux measurements will continue at FK site to further investigate inter-annual variability in NEE. to better understand these exchange mechanism and in-depth analysis, process-level field experiments and intensive short-term intercomparisons are also expected to be followed.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.24 no.3
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• pp.375-388
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• 2019

Accurate evaluation of sea-to-air $CO_2$ flux and its variability is crucial information to the understanding of global carbon cycle and the prediction of atmospheric $CO_2$ concentration. $fCO_2$ observations are sparse in space and time in the East Sea. In this study, we derived high resolution time series of surface $fCO_2$ values in the southwest East Sea, by feeding sea surface temperature (SST), salinity (SSS), chlorophyll-a (CHL), and mixed layer depth (MLD) values, from either satellite-observations or numerical model outputs, to three machine learning models. The root mean square error of the best performing model, a Random Forest (RF) model, was $7.1{\mu}atm$. Important parameters in predicting $fCO_2$ in the RF model were SST and SSS along with time information; CHL and MLD were much less important than the other parameters. The net $CO_2$ flux in the southwest East Sea, calculated from the $fCO_2$ predicted by the RF model, was $-0.76{\pm}1.15mol\;m^{-2}yr^{-1}$, close to the lower bound of the previous estimates in the range of $-0.66{\sim}-2.47mol\;m^{-2}yr^{-1}$. The time series of $fCO_2$ predicted by the RF model showed a significant variation even in a short time interval of a week. For accurate evaluation of the $CO_2$ flux in the Ulleung Basin, it is necessary to conduct high resolution in situ observations in spring when $fCO_2$ changes rapidly.

• Journal of the Korean Chemical Society
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• v.30 no.5
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• pp.415-422
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• 1986

The metal-support interaction of copper oxide supported on ${\gamma}$-alumina and silica was studied by X-ray diffraction (XRD) and temperature-programmed reduction(TPR). It was found that XRD pattern of CuO can not be observed up to 5.0wt % copper content for CuO/${\gamma}-Al_2O_3$ while CuO/$SiO_2$ sample shows the CuO pattern even at 2.5wt% copper content. $H_2-$TPR of CuO/${\gamma}-Al_2O_3$ system shows four major peaks at 145${\circ}C$, 185${\circ}C$, 210${\circ}C$, and 250${\circ}C$. In the case of CuO/$SiO_2$, a large peak at 250${\circ}C$ was appeared accompanying a small peak at 425${\circ}C$. Comparing the TPR peaks with that of copper aluminate which was prepared from the calcination of CuO/${\gamma}-Al_2O_3$ at 1000${\circ}C$, the peaks at around 145${\circ}C$, 200${\circ}C$ (185${\circ}C$ and 210${\circ}C$), and 250${\circ}C$ were corresponded to $Cu^+$ ion in CuO interacting ${\gamma}-Al_2O_3$, $Cu^+$ ions in defect sites of ${\gamma}-Al_2O_3$ and $Cu^{2+}$ ion in the bulk CuO layer, respectively. From the results, it was concluded that there is considerable metal-support interaction in CuO on ${\gamma}-Al_2O_3$ and the interaction results in a stabilization of $Cu^+$ ion in the system.

• Korean Journal of Poultry Science
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• v.13 no.1
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• pp.1-14
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• 1986

The subject of this study was to obtain some genetic information for developing superior layer chickens. Heterosis and combining ability effects were estimated with 5,759 progenies of full diallel crosses of 6 strains in White Leghorn. Fertility, hatchability, brooder-house viability, rearing- house viability, laying-house viability, age at 1st egg laying, body weight at 1st egg laying, average egg weight, hen-day egg production, hen-housed egg production, and feed conversion were investigated and analyzed into heterosis effect, general combining ability, specific combining ability and reciprocal effect by Grilling's model I. The results obtained were summarized as follows; 1. The general performance of each traits was 94.76% in fertility, 74.05% in hatchability, 97.47% in brooder-house viability, 99.72% in rearing-house viability, 93.81% in laying-house viability, 150 day in the age at 1st egg laying, 1,505g in the body weight at 1st egg laying, 60.08g in average egg weight, 77.11% in hen-day egg production, 269.8 eggs in hen-housed egg Production, and 2.44 in feed conversion. 2. The heterosis effects were estimated to -0.66%, 9.58%, 0.26%, 1.83%, -3.87%, 3.63%, 0.96%, 4.23%, 6.4%, and -0.8%, in fertility, hatchability, brooder-house viability, laying-house viability, the age at 1st egg laying, the body weight at 1st egg laying, average egg weight, hen-day egg Production, hen-housed egg production and feed conversion, respectively. 3. The results obtained from analysis of combining ability were as follows ; 1) Estimates of general combining ability, specific combining ability and reciprocal effects were not high in fertility. It was considered that fertility was mainly affected by environmental factors. In the hatchability, the general combining ability was more important than specific combining ability and reciprocal effects, and the superior strains were K and V which the additive genetic effects were very high. 2) In the brooder-house viability and laying-house viability, specific combining ability and reciprocal effects appeared to be important and the combinations of K${\times}$A and A${\times}$K were very superior. 3) In the feed conversion and average egg weight, general combining ability was more important compared with specific combining ability and reciprocal effects. On the basis of combining ability the superior strains were F, K and B in feed conversion, F and B in the average egg weight. 4) General combining ability, specific combining ability and reciprocal effects were important in the age at 1st egg laying and the combination of V ${\times}$F, F${\times}$K and B${\times}$F were very useful on the basis of these effects. In the body weight at 1st egg laying, general combining ability was more important than specific combining ability and reciprocal effects, relatively. The K, F and E strains were recommended to develop the light strain in the body weight at 1st egg laying. 5) General combining ability, specific combining ability and reciprocal effects were important in the hen-day egg production and hen-housed egg production. The combinations of F${\times}$K, A${\times}$K, and K${\times}$A were proper for developing these traits. 4. In general, high general combining ability effects were estimated for hatchability, body weight at 1st egg laying, average egg weight, hen-day egg production, hen-housed egg production, and feed conversion and high specific combining ability effects for brooder-house viability, laying house viability, age at 1st egg laying, hen-day egg production and hen-housed egg production, and high reciprocal effects for the age at 1st egg laying.

• Horticultural Science & Technology
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• v.33 no.3
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• pp.403-408
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• 2015

Color is one of the quality determining factors for pepper powder. To measure the color of pepper powder, several methods including high-performance liquid chromatography (HPLC), thin layer chromatography (TLC), and ASTA-20 have been used. Among the methods, the ASTA-20 method is most widely used for color measurement of a large number of samples because of its simplicity and accuracy. However it requires time consuming preprocessing steps and generates chemical waste containing acetone. As an alternative, we developed a fast and simple method based on a visible/near infrared (Vis/NIR) hyperspectral method to measure the color of pepper powder. To evaluate correlation between the ASTA-20 and the visible/near infrared (Vis/NIR) hyperspectral methods, we first measured the color of a total of 488 pepper powder samples using the two methods. Then, a partial least squares (PLS) model was postulated using the color values of randomly selected 3 66 samples to predict ASTA values of unknown samples. When the ASTA values predicted by the PLS model were compared with those of the ASTA-20 method for 122 samples not used for model development, there was very high correlation between two methods ($R^2=0.88$) demonstrating reliability of Vis/NIR hyperspectral method. We believe that this simple and fast method is suitable for highthroughput screening of a large number of samples because this method does not require preprocessing steps required for the ASTA-20 method, and takes less than 30 min to measure the color of pepper powder.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.1
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• pp.95-107
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• 2017

In this study, a preliminary study was undertaken for development of a tunnel incident automatic detection system based on a machine learning algorithm which is to detect a number of incidents taking place in tunnel in real time and also to be able to identify the type of incident. Two road sites where CCTVs are operating have been selected and a part of CCTV images are treated to produce sets of training data. The data sets are composed of position and time information of moving objects on CCTV screen which are extracted by initially detecting and tracking of incoming objects into CCTV screen by using a conventional image processing technique available in this study. And the data sets are matched with 6 categories of events such as lane change, stoping, etc which are also involved in the training data sets. The training data are learnt by a resilience neural network where two hidden layers are applied and 9 architectural models are set up for parametric studies, from which the architectural model, 300(first hidden layer)-150(second hidden layer) is found to be optimum in highest accuracy with respect to training data as well as testing data not used for training. From this study, it was shown that the highly variable and complex traffic and incident features could be well identified without any definition of feature regulation by using a concept of machine learning. In addition, detection capability and accuracy of the machine learning based system will be automatically enhanced as much as big data of CCTV images in tunnel becomes rich.

• Journal of Korean Society of Forest Science
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• v.81 no.4
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• pp.337-345
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• 1992

In this research, a kinematic wave model was applied for the runoff analysis, Regulation of streamflow was estimated by the calibration of roughness coefficient as a parameter. The data analyzed were obtained from Ananomiya and Shirasaka experimental basins at Tokyo University Forest in Aichi. Estimation methods and characteristics of roughness coefficient as a evaluation method of hydrological function of forest are summarized as follows ; 1. Roughness coefficient($N_s$) indicates the resistance of hillslope to the flowing water of surface runoff. There exists an hypothesis that resistance of hillslope to flowing water increase with the growth forest and development of the $A_o$ layer. 2. Roughness coefficient($N_s$) was estimated by the parameter when the stream direct runoff was calculated by using the kinematic wave. 3. Secular change of '$N_s$' in ananomiya has a curve which has an upper limit and increases exponentially near the limit. The curve quickly increased from 1935 to 1945 when results of afforestation for erosion control were thought to be effective. On the other hand, slight increase of '$N_s$' in Shirasaka indicates that there was not such a big change in the surface of soil layer. 4. The increase of '$N_s$' was related with decrease of direct runoff and increase of base flow. It was recognized that the rate of direct runoff decreased with the improvement of forest physiognomy and the rate of base flow was increased. But absolute value of water runoff per one storm decreased in chronological order.