• Journal of the Korean Institute of Gas
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• v.26 no.3
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• pp.45-53
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• 2022

In order to improve the emission of diesel engines, natural gas-diesel dual fuel combustion compression ignition engines are in the spotlight. In particular, a reactivity controlled compression ignition (RCCI) combustion strategy is investigated comprehensively due to its possibility to improve both efficiency and emissions. With advanced diesel direct injection timing earlier than TDC, it achieves spontaneous reaction with overall lean mixture from a homogeneous mixture in the entire cylinder area, reducing nitrogen oxides (NOx) and particulate matter (PM) and improving braking heat efficiency at the same time. However, there is a disadvantage in that the amount of incomplete combustion increases in a low load region with a relatively small amount of fuel-air. To solve this, sensitive control according to the diesel injection timing and fuel ratio is required. In this study, experiments were conducted to improve efficiency and exhaust emissions of the natural gas-diesel dual fuel engine at low load, and evaluate combustion stability according to the diesel injection timing at the operation point for power generation. A 6 L-class commercial diesel engine was used for the experiment which was conducted under a 50% load range (~50 kW) at 1,800 rpm. Two injectors with different spray patterns were applied to the experiment, and the fraction of natural gas and diesel injection timing were selected as main parameters. Based on the experimental results, it was confirmed that the brake thermal efficiency increased by up to 1.3%p in the modified injector with the narrow-angle injection added. In addition, the spray pattern of the modified injector was suitable for premixed combustion, increasing operable range in consideration of combustion instability, torque reduction, and emissions level under Tier-V level (0.4 g/kWh for NOx).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.1
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• pp.27-33
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• 2023

Several domestically consumed sweetpotato derivatives, such as sweetpotato starch for processing raw materials, frozen and refrigerated paste, and powder are dependent on imports. This study was conducted to examine the suitability of sweetpotato cultivars of twelve varieties (powdery-type and viscous type) cultivated in paddy fields, for use in starch, chips, dried products, and beverages. The two-year average yield results of the four cultivars suitable for starch (in order of highest to lowest yield) was as follows: Gogeonmi (4,018 kg/10a); Daeyumi (3,615 kg/10a); Jinhongmi (3,426 kg/10a); Singeonmi (2,837 kg/10a). The starch content was 20.2%, 18.2%, 21.2%, and 20.6% in Daeyumi, Gogeonmi, Singeonmi, and Jinghongmi, respectively. The total amount of starch was higher in Daeyumi (730 kg/10a) and Gogeonmi (731 kg/10a) than that in Singeonmi and Jinghongmi. The yield of Pungwonmi and Shinjami were 4,443 and 3,602 kg/10a, respectively. Powdery-type sweetpotatoes (Daeyumi and Gogeonmi) showed the low decay rates of all cultivars (0.8 and 0%, respectively). The yield of the storage root formation and storage root swelling stages by water-logging treatment decreased by 16.5% and 15.4% for Pungwonmi, and by 17.2% and 10.0% for Shinjami. Drainage management of paddy fields is necessary to reduce the damage caused by water-logging. Our results suggest that cultivation of sweetpotato varieties suitable for processing raw materials in paddy fields will enable stable yields of sweetpotato with a high starch content.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.1
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• pp.20-26
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• 2023

Fiber content in the storage roots of sweetpotato varies between different varieties. For examples, the high fiber content of certain types has a poor texture when steamed or roasted. This study was conducted to evaluate the optimal sieve mesh size for separating fibers, the chemical composition of fibers and differences in fiber content among different varieties. We found that the separated fiber content (dry weight) of mashed and steamed sweetpotato was higher after washing three times (143.3 mg/100 g) compared with that washed five times (128.4 mg/100 g). The Hogammi variety remained 85.9% of total fiber content at 10 mesh (2,000 ㎛) and 9.6% of total fiber content at 30 mesh (600 ㎛), and Jinyulmi remained 74.9 and 16.7% of total fiber content , respectively. Therefore, a 30 mesh sieve was considered the most suitable for fiber separation. Among the 10 studied cultivars, Jinhongmi showed the lowest amount of fiber (24.8 mg/100 g) and Hogammi had the highest amount (111.4 mg/100 g), which was 4.5 times larger than that of Jinhongmi. Cellulose, hemicellulose and lignin content of separated fibers showed no difference between the viscous-type Hogammi and powdery-type Jinyulmi varieties, with averages of 32.5, 22.3 and 29.6%, respectively. Correlation results using the Image J program showed a significant correlation between the distribution of the stained area and the fiber content (R = 0.74, p < 0.05). Staining distribution differed among varieties, suggesting that a simple fiber content test could be performed using the staining method on raw sweetpotato. These results provide useful information to help inform farmers on the fiber content of different sweetpotato varieties.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.7
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• pp.802-811
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• 2023

Marine spatial planning (MSP) is a crucial element for rational allocation and sustainable use of marine areas. Particularly, Fishing Activity Protected Areas constitute essential zones accounting for 45.6% designated for sustainable fishing activities. However, the current assessment of these zones does not adequately consider future demands and potential values, necessitating appropriate evaluation methods and predictive tools for long-term planning. In this study, we selected key fish species (Scomber japonicus, Trichiurus lepturus, Engraulis japonicus, and Larimichthys polyactis) within the Fishing Activity Protected Area to predict their distribution and compare it with the current designated zones for evaluating the ability of the prediction tool. Employing the Intergovernmental Panel on Climate Change (IPCC) 6th Assessment Report scenarios (SSP1-2.6 and SSP5-8.5), we used species distribution models (such as MaxEnt) to assess the movement and distribution changes of these species owing to future variations. The results indicated a 30-50% increase in the distribution area of S. japonicus, T. lepturus, and L. polyactis, whereas the distribution area of E. japonicus decreased by approximately 6-11%. Based on these results, a species richness map for the four key species was created. Within the marine spatial planning boundaries, the overlap between areas rated "high" in species richness and the Fishing Activity Protected Area was approximately 15%, increasing to 21% under the RCP 2.6 scenario and 34% under the RCP 8.5 scenario. These findings can serve as scientific evidence for future evaluations of use zones or changes in reserve areas. The current and predicted distributions of species owing to climate change can address the limitations of current use zone evaluations and contribute to the development of plans for sustainable and beneficial use of marine resources.

• Journal of Ginseng Research
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• v.23 no.2 s.54
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• pp.105-114
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• 1999

To investigate the effects of korean ginseng on the expression of transferrin receptor (TfR) in the liver cell membrane, we had carried out the experiments of $[^{3}H]thymidine$ uptake, $^{125}I-transferrin$ binding, and TfR mRNA expression in the liver after partial hepatectomy of normal and 3'-methyl-4-dimethylaminoa-zobenzene (3'-Me-DAB) treated rat with or without treatment of korean gingseng. $[^3H]thymidine$ uptake was not changed in the liver of 3'-Me-DAB or ginseng treated rat compared to that of control rat, but increased in that of partial hepatectomy of normal or 3'-Me-DAB treated rat. And this increased $[^{3}H]thymidine$ uptake was lowered slightly by the treatment of ginseng. Transferrin binding sites in the liver plasma membrane of ginseng treated rat with or without partial hepatectomy were similar, but increased in that of 3'-Me-DAB treated rat with or without partial hepatectomy compared to those of each control rat and these increased binding sites were reduced by ginseng treatment. Transferrin binding affinity (l/kd) was not changed by ginseng treatment, but tended to decrease in the liver of 3'-Me-DAB treated rat or in those after partial hepatectomy of all groups and reverse by ginseng treatment in 3'-Me-DAB treated rat. The expression of TfR mRNA was increased in the liver of 3'-Me-DAB treated rat with partial hepatectomy (peak at 24 hours), but lowered by ginseng treatment in this rat. From these results, it is suggested that korean ginseng has no effect on the increased expression of TfR with decreased affinity in the cell membrane of regenerated liver after partial hepatectomy of rat, but could inhibt that of 3'-Me-DAB treated rat through the regulation of DNA synthesis or TfR mRNA in partial.

• Journal of Nutrition and Health
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• v.53 no.3
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• pp.231-243
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• 2020

Purpose: To determine the metabolic influence of the traditional Korean diet (K-diet), which has been regarded as a healthy diet, we investigated the profile of urine organic acids that are intermediates of various types of metabolism including energy metabolism. Methods: Ten women aged 50-60 years were recruited and randomly divided into 2 diet groups, K-diet and control diet, the latter of which is a Westernized Korean diet that is commonly consumed by Koreans nowadays. Before and after the 2-week intervention, 46 urine organic acids were determined using LC/MS/MS, along with clinical parameters. Results: The average concentrations of succinate (4.14 ± 0.84 ㎍/mg creatinine vs. 1.49 ± 0.11, p = 0.0346) and hydroxymethylglutarate (3.67 ± 0.36 ㎍/mg creatinine vs. 2.97 ± 0.29, p = 0.0466), both of which are intermediates of energy metabolism, decreased in the K-diet group after the 2-week intervention, but these were not observed in the control diet group. In particular, the average concentration of succinate in the K-diet group was lower than that in the control group (3.33 ± 0.56 ㎍/mg creatinine vs. 1.49 ± 0.11, p = 0.0284) after 2 weeks. The concentrations of two tryptophan metabolites, 5-hydroxyindolacetate (3.72 ± 0.22 ㎍/mg creatinine vs. 3.14 ± 0.21, p = 0.0183) and indican (76.99 ± 8.35 ㎍/mg creatinine vs. 37.89 ± 10.06, p = 0.0205) also decreased only in the K-diet group. After the 2-week intervention, the concentration of kynurenate, another tryptophan metabolite, was lower in the K-diet group than that in the control diet group (3.96 ± 0.51 ㎍/mg creatinine vs. 2.90 ± 0.22, p = 0.0356). Interestingly, the urine level of kynurenate was positively correlated with BMI (r = 0.61424, p = 0.0003) and total cholesterol (r = 0.46979, p = 0.0088), which decreased only in the K-diet group (239.40 ± 15.14 mg/dL vs. 198.20 ± 13.25, p = 0.0163). Conclusion: The K-diet alters the urinary excretion of organic acids involved in energy metabolism and tryptophan metabolism, suggesting the influence of the K-diet on these types of metabolism. Urine organic acids changed by the K-diet may serve as biomarkers in future studies.

• Korean Journal of Oriental Medicine
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• v.3 no.1
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• pp.1-15
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• 1997

${\ulcorner}$Classified Collection of Medical Prescriptions${\lrcorner}$(1445) is a book compiled the medical achievements of China and Choseon in those times and it's our source of pride to have it In this country. It also deserves careful investigation since this book can provide some clues of features of missing books in China and Korea. The extent of accuracy of xylographica of old books determines the possiblity of in depth further study. So authors attempted to investigate the xylographica of ${\ulcorner}$Classified Collection of Medical Prescriptions${\lrcorner}$ one of the 3 main books in Korea. Previous investigation done by Miki Sakae and Kim Doo Jong are noticeable. On the basis of their respective works, we analyzed 'Annals of the Choseon Dynasty' to find records related with ${\ulcorner}$Classified Collection of Medical Prescriptions${\lrcorner}$ and estimated the situation of its publication. We tried figure the situation of those times of China, Japan and Korea(including North Korea) and tried to estimate the book's original xylographica as much as we could. By King Sejong's command, the first draft of ${\ulcorner}$Classified Collection of Medical Prescriptions${\lrcorner}$ consisted of 365 books was made by collaboration of civil officials and medical officers during the period from 1443 to 1445. And then from 1451(first year of Moonjong's reign) to 1464(l0th year of Sejo's reign) lots of manpowers were employed and through the process of countless erasure, proofreading, arrangement and rearrangement revised version of ${\ulcorner}$Classified Collection of Medical Prescriptions${\lrcorner}$ which is called by Sejo text was completed. After 3 years of wood engraving work, the first printed form of ${\ulcorner}$Classified Collection of Medical Prescriptions${\lrcorner}$ (alternately called Seongjong text) in folding case consisted of 266 chapters, 264 volumes came into the world in 1477.(8th year of Seongjong's reign). This was 32 years after the initial completion of the edition. So ${\ulcorner}$Classified Collection of Medical Prescriptions${\lrcorner}$ exists in three forms as Sejong text, Sejo text and Seongjong text respectively. Since those texts were plundered during the Japanese invasion of Korea in 1592, none of the original copy remains within korea. The texts were constantly moved to kadeungcheongieong, to Kongdeungpyeongio, Jesookoan of Edo, to East University of department of classic books, to Cheoncho archives, to the Imperial Museum and finally is kept in the royal palace at present. (Doseoryo text Eulhae printing type) Reduced-size republication books of ${\ulcorner}$Classified Collection of Medical Prescriptions${\lrcorner}$ in wooden type were imported at the time of 'Byeongja Korea-Japan Treaty in 1876' and of those 2 books, one copy was treasured in the Royal Household of the Yi Dynasty and than was lost during the Korean War circa 1950. The other remaining copy has been kept succesively by Kojong's imperial grant, Royal doctor Hong Cheol Bo, Hong Taek Joo, Hong Ik Pyo the book agent, and now is kept In Yonsei University Library and this is the only existing copy in Korea at present. In 1965, Dongyang Medical college published the transcription version of ${\ulcorner}$Classified Collection of Medical Prescriptions${\lrcorner}$ consisting of 11 books and then in 1981 after edition and arrangement by Choonghoa(中華) publishing company, photoprint copy of ${\ulcorner}$Classified Collection of Medical Prescriptions${\lrcorner}$ was published in Keumgang(金剛) publishing company In 1991, October Yeokang(驛江) publishing company producd photocopies of ${\ulcorner}$Classified Collection of Medical Prescriptions${\lrcorner}$ which were previously translated into Korean by North Korea Institute of Oriental Medicine and then issued by medical publishing company. In China, two institutes, Zhejiang Institute of Traditional Chinese Medicine and Huzhou Traditional Chinese Medical Hospital cooperated to publish a revised and marked text consiting of 11 books by adding marking points to japanse Edohakhoondang text which were used as a reference. Both the korean and chinese texts issued were grounded by the ${\ulcorner}$Classified Collection of Medical Prescriptions${\lrcorner}$ kept in the royal palace. Any further study concerning ${\ulcorner}$Classified Collection of Medical Prescriptions${\lrcorner}$ can acquire its accuracy and objectivity when the japanese text kept in the royal palace is taken as an original copy.

• Journal of the Korean Geographical Society
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• v.50 no.6
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• pp.571-605
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• 2015

This research revealed that 'Yipjiamlyu' in the Mukedeng's map is geographically 'a beginning point of underf low,' whose location is on the Heishigou's riverbed(E.L. 1,840m) in the NNE side of Daegakbong peak, and that 'Tomungangweon'(Heishigou) is one of the upstream reach of the Sungari River, which, according to historical documents and my fieldwork, Mukedeng also knew at the time of Yimjin(1712) Boundary Making and Demarcation(YBMD). These findings suggest the need to reinterpret the processes of YBMD. Mukedeng set up the Baekdusanjeonggyeobi on the mistaken assumptions on the linkage of 'Yipjiamlyu' and Tumen River. It should have been set up on the Daeyeonjibong peak. Mukedeng found the 'Yipjiamlyu' on the riverbed of 'Tomungangweon'(Heishigou), went downstream, and realized that this river did not flow into the Tumen River. During the search for the source of Tumen River, he found a water stream, and regarded it as the source of Tumen River. He speculated that the water at the 'Yipjiamlyu' flows through the underground to reappear at the his 'identified' source of Tumen River. Consequently, he adjured the construction of demarcation from Baekdusanjeonggyeobi through 'Yipjiamlyu' to the his 'identified' source of Tumen River. The water stream pointed as the source of Tumen River, however, was not part of the upstream reach of Tumen River. Actually, Korean officials, who were in charge of establishing boundary features, set up the demarcation from Baekdusanjeonggyeobi through Huanghuasongdianzi to the true source of Tumen River identified by themselves, which Mukedeng had not intended. The ambiguity of the location of 'Yipjiamlyu' caused a difference between Mukedeng's original request and Korean officials' implementation in the boundary demarcation. Throughout the whole processes of YBMD, Korea(Joseon) and China(Qing) both mistook the real geography of the river system. Their understanding on Yalu River system was correct. But the identification of the spring source of the Tumen River by Korean participants was the only geographically correct result related on this river system in YBMD.

• Journal of Korean Society of Forest Science
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• v.75 no.1
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• pp.1-18
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• 1986

This study was initiated to estimate productivity of Quercus variabilis stand. However the practical objective of this study was to provide some information to establish the basis of selecting the suitable site for Quercus variabilis. The productivity measured in terms of DBH, height, basal area and stem volume was hypothesized, respectively, to be a function of a group of factors. This study considered 32 factors, 20 of which were related to the forest environmental factors such as tree age, latitude, percent slope, etc. and the rest of which were related to soil factors such as soil moisture, total nitrogen, available $P_2O_5$, etc. The data on 4 productivity measurements of Quercus variabilis growth and related factors cited were collected from 99 sample plots in Kyeongbook and chungbook provinces. Some factors considered were, in nature, discrete variables and the others continuous variables. Each kind of factor was classified into 3 or 4 categories and total numbers of such categories were eventually amounted to 110. Then each category was treated as an independent variable. This is amounted to saying that individual variable was treated a dummy variable and assigned a value 1 or 0. However the first category of each factor was deleted from the normal equation for statistical consideration. First of all, each of 4 productivity measurements of Quercus variabilis growth was regressed and, at the same time, those 110 categories. Secondly, the partial correlation coefficients were measured between each pair of 4 productivity measurements and 32 individual foctors. Finally, the relative scores were estimated in order to derive the category ranges. The result of these statistical analyses could be summarized as follows: 1) Growth measurement in terms of height seems to be a more significant criterion for estimation of productivity of Quercus variabilis. 2) Productivity of forest on stocked land may better be estimated in terms of forest environmental factors, on the other hand, that of unstocked land may be estimated in terms of physio-chemical factors of soil. 3) The factors that a strongly positive relation to all growth factors of tree are age group, effective soil, soil moisture, etc. This implies that these factors might effectively be used for criteria for selecting the suitable site for Quercus variabilis. 4) Parent rock, latitude, total nitrogen, age group, effective soil depth, soil moisture, organic matter, etc., had more significant category range for tree growth. Therefore, the suitable site for Quercus variabilis may be selected, based on this information. In conclusion, the above results obtained by the multivariable analysis can be not only the important criteria for estimating the growth of Quercus variabilis but also the useful guidance for selecting the suitable sites and performing the rational of Quercus variabilis forest.

• Korean Journal of Animal Reproduction
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• v.24 no.4
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• pp.395-406
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• 2000

The present study was conducted to examine the developmental capacity of mouse oocytes within prenatal follicles cultured various concentrations of FSH and LH and the expression of cytochrome P450 cholesterol side-chain cleavage enzyme (P450scc) and cytochrome P450 17 $\alpha$ -hydroxylase (P450)$_{17{\alpha}}$ mRNA, as luteinization and atretic marker, in these culture conditions. In addition, we investigated the concentrations of progesterone and testosterone in culture medium. The developmental potential up to blastocyst of the oocytes grown in vitro was higher in the FSH alone (30.2%) and 10 $m\ell$U/$m\ell$ LH and 100 $m\ell$U/$m\ell$ FSH treated (28.0%) groups than in the 100 $m\ell$U/$m\ell$ LH and 100 $m\ell$U/$m\ell$ FSH treated group (22.0%). And the mean numbers of cell per blastocyst was higher in the FSH alone (50.9$\pm$26.1) and 10 $m\ell$U/$m\ell$ LH and 100 $m\ell$U/$m\ell$ FSH treated (51.0$\pm$21.1) groups when compared to the 100 $m\ell$U/$m\ell$ LH and 100 $m\ell$U/$m\ell$ FSH treated group (45.2$\pm$15.1). The expressions of P450scc and P450$_{17{\alpha}}$ mRNA in the oocyte -cumulus complexes were increased with increasing of LH concentration, and also the secretions of progesterone and testosterone were increased. Especially, in the 100 $m\ell$U/$m\ell$ LH and 100 $m\ell$U/$m\ell$ FSH treated group, the expression of P450scc and P450$_{17{\alpha}}$ were significantly increased, and the secretion of progesterone and testosterone were significantly increased. Therefore, these data show that gonadotrophins are essential for the in vitro culture of preantral follicles, but that increasing of LH concentration is reduced the developmental capacity of oocytes. The cause of these findings may be due to increasing of progesterone and testosterone secretion by the enhance of P450scc and P450$_{17{\alpha}}$ mRNA expressions, as markers of luteinization and atresia. Conclusively, this study suggest that supplementation of 100 $m\ell$U/$m\ell$ FSH or 10 $m\ell$U/$m\ell$ LH and 100 $m\ell$U/$m\ell$ FSH may be optimal condition for the culture of mouse pre antral follicles.