• Proceedings of the Ginseng society Conference
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• 2002.10a
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• pp.55-65
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• 2002

Ginseng has been used as a key constituent in traditional medicine prescriptions for centuries. Other than its well-known anti-stress and adaptogenic properties, ginseng has also been shown to be very effective in treating age-related deterioration in metabolic and memory functions. Although it is generally believed that the saponin (GS) fraction of the ginseng root accounts for the bioactivity of ginseng, a direct demonstration on which ginsenoside does what is still generally lacking. In the past decade, our laboratory has endeavored to identify the active GS components involved in energy metabolism, memory, and anti-neurotoxicity. To examine the ergogenic effects of GS in enhancing aerobic capacity, rats were subjected to either severe cold ($40^{\circ}C$ under helium-oxygen, two hours) or exercise workload $(70\%\;VO_{2}max,$ to exhaustion). Acute systemic injection (i.p.) of ginseng GS (5-20 mg/kg) significantly elevated both the total and maximum heat production in rats and improved their cold tolerance. However, pretreating the animal with the optimal dose (10 mg/kg) of GS devoid of $Rg_1\;and\;Rb_1$ failed to elicit any beneficial effects in improving cold tolerance. This indicates that either $Rb_1\;and/or\;Rg_1$ may be essential in exemplifying the thermogenic effect of GS. Further studies showed that only pretreating the animals with $Rb_1(2.5-5\;mg/kg),\;but\;not\;Rg_l,$ resulted in an increase in thermogenesis and cold tolerance. In contrast to the acute effect of GS on cold tolerance, enhancement of exercise performance in rats was only observed after chronic treatment (4 days). Further, we were able to demonstrate that both $Rb_1\;and\;Rg_1$ are effective in enhancing aerobic endurance by exercise. To illustrate the beneficial effects of GS in learning and memory, a passive avoidance paradigm (shock prod) was used. Our results indicated that the scopolamineinduced amnesia can be significantly reversed by chronically treating (4 days) the rats with either $Rb_1\;or\;Rg_1$ (1.25 - 2.5 mg/kg). To further examine its underlying mechanisms, the effects of various GS on ${\beta}-amyloid-modulated$ acetylcholine (ACh) release from the hippocampal slices were examined. It was found that inclusion of $Rb_1$ (0.1 ${\mu}M$), but not $Rg_1$, can attenuate ${\beta}-amyloid-suppressed$ ACh release from the hippocampal slices. Our results demonstrated that $Rb_1\;and\;Rg_1$ are the key components involved in various beneficial effects of GS but they may elicit their effects through different mechanisms.

• The Journal of the Acoustical Society of Korea
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• v.40 no.5
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• pp.479-487
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• 2021

In this paper, we propose an Sound Event Detection (SED) model using self-training based on a noisy student model. The proposed SED model consists of two stages. In the first stage, a mean-teacher model based on an Residual Convolutional Recurrent Neural Network (RCRNN) is constructed to provide target labels regarding weakly labeled or unlabeled data. In the second stage, a self-training-based noisy student model is constructed by applying different noise types. That is, feature noises, such as time-frequency shift, mixup, SpecAugment, and dropout-based model noise are used here. In addition, a semi-supervised loss function is applied to train the noisy student model, which acts as label noise injection. The performance of the proposed SED model is evaluated on the validation set of the Detection and Classification of Acoustic Scenes and Events (DCASE) 2020 Challenge Task 4. The experiments show that the single model and ensemble model of the proposed SED based on the noisy student model improve F1-score by 4.6 % and 3.4 % compared to the top-ranked model in DCASE 2020 challenge Task 4, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.8
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• pp.279-285
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• 2019

Transverse vibrations of a ship's aft end and deckhouse are mainly induced by transverse exciting forces from the main engine. Resonance should be avoided in the initial design stages when there is a prediction of resonance between the main engine and transverse modes of the deckhouse. Estimates of frequencies for resonance avoidance are possible from the specifications of the main engine and propeller, but the inherent vibration frequency of the structure around the engine room is not easy to estimate due to the variation in the shape. Experience-oriented vibration design is also carried out, which results in many problems, such as process delay, over-injection of on-site personnel, and iterative performance of the design. For the flexible design of 8,600 TEU container vessels, this study addressed the resonance problem caused by the transverse vibration of the main engine when only the main engine was changed from 12 cylinders to 10 cylinders without modification of the hull structure layout. Efficient structural reinforcement design guidelines are presented for avoiding resonances with the main engine lateral vibration and the structure around the engine room. The guidelines are expected to be used as practical design guidelines at design sites.

• Fire Science and Engineering
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• v.32 no.6
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• pp.1-6
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• 2018

This study is to analyze the characteristics of the yellow insulation ring type of the CSST used for tubing when it is artificially deteriorated and damaged by burning. The CSST for tubing consists of a tube, protective coating, nut, yellow insulation ring, packing, and socket. In addition, it is thought that a yellow insulation ring and rubber packing were used to connect the tube and socket in order to improve the airtightness and insulation performance. The result of the verification of the data acquired from the tests in the 95% confidence interval shows that the Anderson-Darling (AD) and P value were analyzed to be 0.945 and 0.015, respectively. This confirms that the test data of the CSST for tubing is reliable. The analysis of the arithmetic mean of the insulation resistance of a CSST showed that the CSST damaged by burning by a torch, and the one damaged by electrical burning, was $16.7k{\Omega}$ (the greatest relatively) and $208{\Omega}$ (the lowest), respectively, while it was $1.72k{\Omega}$ in the case of a normal product. Therefore, the analysis result of the insulation resistance of the CSST collected from the scene of a fire can be utilized to examine the cause of damage by burning. In addition, it was found that when the maximum current of 97 A was applied to the CSST for about 5 s using a Primary Current Injection Test System (PCITS) the protective film and insulation ring of the CSST has no difference from that of a normal product. However, a part of the metal tube was melted.

• Journal of the Korean Institute of Gas
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• v.25 no.6
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• pp.22-28
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• 2021

Combustion characteristics were examined experimentally for a swirl-stabilized double cone premixed burner nozzle used for industrial gas turbines for power generation. An original model and a variant with a different fuel injection pattern are tested to compare their combustion characteristics such as NOx, CO and stability in pressurized conditions with single burner-flame and in an ambient multi-flame conditions with multi-burners. Test results show that NOx emissions are smaller for the variant, whose number of fuel holes is reduced with the same total area of fuel holes, in ambient and pressurized single-flame conditions with single burner, which results from enhanced fuel/air mixing due to a higher penetration of fuel into the air stream. The multi-burnerflame test results show that NOx emissions are smaller for the variant due to reduced flame interactions, which, on the contrary, slightly reduces the stability margin. On-site test results fromin an actual power plants also show that NOx emissions are reduced for the variant, compared with the original one, which is in agreement with the lab test results stated above.

• Journal of fish pathology
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• v.37 no.1
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• pp.111-122
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• 2024

This study assessed the impact of the toltrazuril derivative N-(4-(4-Fluorophenoxy)-3-methylphenyl) acetamide on natural cytotoxic cell (NCC) activity of olive flounder, Paralichthys olivaceus spleen. Five groups of fifteen olive flounder, comprising non-treatment and vehicle control groups, were randomly assigned. N-(4-(4-Fluorophenoxy)-3-methylphenyl) acetamide was injected intramuscularly at doses of 120, 150 and 200 mg/kg body weight; a total of ten injections were given over the course of 30 days. The NK activity of flounder splenic cells was evaluated against YAC-1, mouse lymphoma cells or HINAE cells with a choice of co-cultivation times of 4 or 18 hrs. In case of YAC-1 co-culture we observed a significant increase in cytotoxicity at a dose of 200 mg/kg, up to 3.06 times more than that of the control group. Only the trial with the 4 hrs co-culture produced a significant difference in the HINAE cell experiment; the experimental group at the 200 mg/kg dose exhibited the maximum cytotoxicity, demonstrating 2.3 times more cytotoxicity than the control group. Furthermore, the expression level of IL-12b was markedly induced in the group with 200 mg/kg, which was 6.62 times greater than that of the control group. In terms of the altered NK cell activity, the repeated high doses of N-(4-(4-Fluorophenoxy)-3-methylphenyl) acetamide can cause changes in the normal performance of immune function.

• Korean Journal of Animal Reproduction
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• v.26 no.3
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• pp.291-298
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• 2002

This study was carried out to investigate the reproductive status and the effect of progesterone treatment on the recovery of reproductive disorders in Hanwoo. Hanwoo farms were surveyed the general management status, such as the type of barn, the feed intake, the incidence of reproductive disorders. The reproductive disorder cattle were treated 7 days insertion of control internal drug releasing for cattle (CIDR) and injection of PGF$_2$$\alpha$ at 1 day before removal. The recovery of reproductive disorders was assessed by determining the pregnancy following artificial insemination. The total number of surveyed Hanwoo farms was 127, and the total incidence rate of reproductive disorders was 19.7% (209/1,061). Compared to the herd size, the incidence rates of reproductive disorders in less than 10 heads (37.5%) was significantly (P<0.05) higher than in 10 to 20 heads (14.7%) and more than 20 heads (13.6%) of herd size per farm. The incidence rate of reproductive disorders in tie stall barn was significantly (P<0.05) higher than in free stall barn (30.4% vs. 14.7%), and even in free stall barn, that tended to decrease as the floor area was larger. The incidence rate of reproductive disorder by the parity was highest in heifer (50.7%), and that tended to decrease as the parity was increased. The distribution rate of the case of reproductive disorder in anestrus, recovery rate of reproductive disorders fellowing CIDR treatment was 75.1% (157/209). In the recovery rate of reproductive disorders by body condition score (BCS), BCS 1, 2 and 3 was significantly (P<0.05) higher pregnancy rate (85.7, 84.9 and 86.8%), and gross recovery rate in emaciated cattle was better than in obese cattle (BCS 4, 5). In conclusion, the incidence rate of reproductive disorders in Hanwoo raised in Youngju province area was 19.7%, and that tended to decrease as the herd size was increase because of increased farmer's attentions, and the floor area was larger. The majority of the case of reproductive disorders was anestrus. The recovery rate of reproductive disorders following CIDR treatment was 75.1%, and to optimize the recovery rate of reproductive disorders, cows and heifers were maintained BCS 1, 2 and 3 by moderate management.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.4
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• pp.394-401
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• 2005

A nonthermal plasma-assisted fuel reformer was developed and the effects of operating variables on the performance of this reformer were studied. The $H_2$-rich reformed gas from the reformer was injected into a diesel engine under an idle condition and the effects of the amount of injected gas on the NO and soot reduction were investigated. It was found that with increasing electric power consumption, the degree of facility of ignition of the reforming reaction in the reformer could be enhanced. The performance of the reformer including $H_2$ concentration, $H_2$ recovery, and energy conversion was affected only by the O/C mole ratio. This was because the equilibrium reaction temperature was governed by the O/C mole ratio. With increasing O/C mole ratio, the $H_2$ recovery and energy conversion passed through the maximum values of 33.4% and 66%, respectively, at an O/C mole ratio between 1.2 and 1.5. The reason why the $H_2$ recovery and energy conversion increased with increasing O/C mole ratio when the O/C mole ratio was lower than $1.2{\sim}1.5$ appeared to be that the complete oxidation reaction occurred more enough with increasing O/C mole ratio in this low O/C mole ratio range and accordingly the reaction temperature increased. Whereas the reason why the $H_2$ recovery and energy conversion decreased with increasing O/C mole ratio when the O/C mole ratio was higher than $1.2{\sim}1.5$ appeared to be that the complete oxidation reaction was further advanced and the $H_2$ recovery and energy conversion decreased. As the weight ratio of reformed diesel to total diesel which entered the diesel engine was increased to $18.2{\sim}23.5%$, NO and soot reduction efficiencies increased and reached as values high as 68.5% and 23.5%, respectively.

• Journal of the Korean Wood Science and Technology
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• v.48 no.4
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• pp.472-487
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• 2020

With the emergence of abnormal climate due to the rapid industrialization, the importance of water quality management and management costs are increasing every year. In Korea, for the management of total phosphorus and total nitrogen, the major materials causing the water quality pollution, coagulants are injected in sewage treatment plants to process organic compounds. However, if the coagulant is injected in an excessive amount to PAC (Poly Aluminium Chloride), a secondary pollution problem might occur. As such, a study on the applicability of natural material-based coagulant is being conducted in Korea. Thus, this study aimed to evaluate the applicability of a mixed coagulant developed by analyzing water quality pollutants T-P, T-N as well as their turbidity, in order to derive the optimum mixing ratio between PAC and torrefied wood flour for the primary settling pond effluent. Under the condition where the content of PAC (10%) and torrefied wood flour is 1%, T-P showed the maximum removal efficiency of 92%, and T-N showed approximately 22%. This indicates that removal of T-N which includes numerous positively charged organic compounds that are equivalent to mixed coagulant is not well accomplished. Turbidity showed the removal efficiency of approximately 91%. As such, 1% of torrefied wood flour was determined to be the optimum addition. As a result of analyzing the removal efficiency for organic compounds by reducing PAC concentration to 7%, T-P showed a high maximum removal efficiency of 91%, T-N showed 32%, and turbidity showed the maximum of 90%. In addition, a coagulation process is performed by using the mixed coagulant based on 1% content of torrefied wood flour produced in this study by performing a coagulation performance comparative experiment with PAC (10%). As a result, PAC concentration was reduced to 30-50%, a similar performance with other coagulants in market was secured, PAC injection amount was reduced that an economic effect can be achieved, and it is considered to perform a stable water treatment that reduces the secondary pollution problem.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.7
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• pp.492-507
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• 2010

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2009. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) Research trends of thermal and fluid engineering have been surveyed as groups of general thermal and fluid flow, fluid machinery and piping, and new and renewable energy. Various topics were covered in the field of general thermal and fluid flow such as an expander, a capillary tube, the flow of micro-channel water blocks, the friction and anti-wear characteristics of nano oils with mixtures of refrigerant oils, etc. Research issues mainly focused on the design of micro-pumps and fans, the heat resistance reliability of axial smoke exhaust fans, and hood systems in the field of fluid machinery and piping. Studies on ground water sources were executed concerning two well type geothermal heat pumps and multi-heat pumps in the field of new and renewable energy. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics and industrial heat exchangers. Researches on heat transfer characteristics included the heat transfer in thermoelectric cooling systems, refrigerants, evaporators, dryers, desiccant rotors. In the area of industrial heat exchangers, researches on high temperature ceramic heat exchangers, plate heat exchangers, frosting on fins of heat exchangers were performed. (3) In the field of refrigeration, papers were presented on alternative refrigerants, system improvements, and the utilization of various energy sources. Refrigeration systems with alternative refrigerants such as hydrocarbons, mixed refrigerants, and $CO_2$ were studied. Efforts to improve the performance of refrigeration systems were made applying various ideas of suction line heat exchangers, subcooling bypass lines and gas injection systems. Studies on heat pump systems using unutilized energy sources such as river water, underground water, and waste heat were also reported. (4) Research trend in the field of mechanical building facilities has been found to be mainly focused on field applications rather than performance improvements. In the area of cogeneration systems, papers on energy and economic analysis, LCC analysis and cost estimating were reported. Studies on ventilation and heat recovery systems introduced the effect on fire and smoke control, and energy reduction. Papers on district cooling and heating systems dealt with design capacity evaluation, application plan and field application. Also, the maintenance and management of building service equipments were presented for HVAC systems. (5) In the field of architectural environment, various studies were carried to improve indoor air quality and to analyze the heat load characteristics of buildings by energy simulation. These studies helped to understand the physics related to building load characteristics and to improve the quality of architectural environment where human beings reside in.