• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.36 no.10
• /
• pp.1001-1009
• /
• 2012

In this study, the cooling characteristics of combustion gas were investigated by injecting liquid nitrogen ($LN_2$) into a liquid rocket combustion chamber, which uses liquid oxygen (Lox) and kerosene as propellants. $LN_2$ injectors and an extended chamber for mixing were installed at the end of the ordinary LRE combustion chamber, and a nozzle was installed after the chamber for mixing. First, an ignition test of the liquid rocket engine was conducted to verify the stable combustion process. Next, a hot firing test was performed step-by-step for safety. Finally, the test was performed for 20 s. The results showed that the combustion gas of the LRE could be successfully cooled by using $LN_2$.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.22 no.1
• /
• pp.138-144
• /
• 2013

The automation technology for overlay welding is needed due to the occurrence of severe corrosion and abrasion on the surface of internal contact in different shape of fittings. In Korea, different shapes of fittings have been manufactured by using the imported equipment of overlay welding automation at some companies. Thus the research on the development of overlay welding automation system (in short, OWAS) for a large L-type tube is urgently needed. In this paper, the investigation is focused on the optimal design of a supporting base for the (currently developing) OWAS of large L-type tube. Specifically we assume that the base which supports the equipment during the process of overlay welding is loaded as self-weight in the direction of gravity through static analysis especially when it is rotated 180 degree on the OWAS. For optimal design of a supporting base for OWAS of large L-type tube, Solidworks(R) (for 3-dimensional modelling) and ANASYS Workbench(R) (for structural analysis) are incorporated so as to proceed an optimization routines based on Response Surface Method (RSM) and Design of Experiment (DOE). In more specific, DOE finds out major factors (or dimensions) of the supporting base by using MINITAB(R). Then the regression equations between design variables (the major factors of supporting base) and response variables (deformation, stress and safety factor for the supporting base), which will be resulted in by RSM, verify the major factors of DOE. In the next step, Central Composite Design (CCD) plans 20 simulations of ANASYS Workbench(R) and then figures out the optimal values of design variables which will be reflected on the manufacturing of supporting base. Finally welding experiment is conducted to figure out the influence of overlay welding quality in applying the optimized design values of supporting base to the actual OWAS.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.16 no.1
• /
• pp.1-8
• /
• 1996

The objective of this study is to obtain the basic data for investigating the effects of organic reserves on winter survial or regrowth yield. Forage rape (Brussicu napus L.) was sown at 10 day> interval from Sep. I to Nov. 1. Field-grown palnts were sampled on the before wintering (Dec. 4) and on the wintering period (Jan. 16) to analyze the nitrogen and non-structural cahohydrate reserves. The rate of winter survival and regrowth yield were also measured in the spring of next year. On the before wintering, the dry matter yields from the plots sown on Sep. 1, Sep.11 and Sep. 21 were 860, 596 and 260 kg/lOa, respectively. No. harvest was canied out on the plots sown after Oct. 1 because the growth state was not enough to cut. Both of nitrogen and starch contents per plant significantly increased as the seeding date was later. On the wintering period, the contents of nitrogen reserves in roots were 176.8. 120.1, 71.7, 84.0, 72.1, 45.3 and 33.3 mg/plant, those of starch reserves were 199.0. 55.8, 21.8, 92.6, 86.5, 36.4 and 29.0 mglplant, resepctively, in the plots sown on Sep. 1, Sep. 11, Sep. 21, Oct. I, Oct. 11, Oct. 21 and Nov. 1. The rates of winter survival were 40, 36, 33, 85, 87, 59 and 49% and regrowth yields were 161, 86, 65, 520, 451, 121 and 33 kgD.M/lOa, respectively, in each plots. 'Ihese results clearly showed that seeding date has a close influence on the level of organic reserves and forage yield, and that the possibility of continuous utilization on the before and alter wintering is extremely limited by seeding date.

• Nutrition Research and Practice
• /
• v.5 no.6
• /
• pp.503-510
• /
• 2011

The aim of this study was to investigate whether a water extract of L. cladonioides (LC) has an anti-obesity effect in 3T3-L1 cells and obese mice. Treatment of differentiated 3T3-L1 adipocytes with LC caused a significant increase in glycerol release and reduced the protein expression of the adipogenic transcription factors, $PPAR{\gamma}$ and C/$EBP{\alpha}$. In an animal model, obese mice were artificially induced by a high fat diet for 10 weeks. Experimental groups were treated with LC (100 mg/kg/day) by gavage for the next 10 weeks. At the end of experiment, the body weight of the LC group mice was reduced by 14.2% compared to the high fat diet (HFD) group. The treatment also decreased liver (31.0%), epididymal (18.0%) and retroperitoneal (19.3%) adipose tissue, and kidney (6.7%) weights, respectively, compared with those of the HFD group. LC prevented diet-induced increases in the serum level of TC (22.6%), TG (11.6%), and glucose (35.0%), respectively, compared with the HFD group. However, the HDL-C level was higher in the LC group (26.1%) than the HFD group. The results of this study thus suggest that LC suppressed lipid accumulation and expression of adipogenic transcription factors, and increased the amount of glycerol release. LC also indicated an anti-obese and anti-hyperlipidemic effect.

• The Journal of Korean Medicine
• /
• v.20 no.4
• /
• pp.69-81
• /
• 2000

Etiology and pathogenesis of hyperlipidemia are considered as 'difficiency in origin' of liver, spleen and kidney combined with 'excess in superficiality' of phlegm stagnancy and blood stasis. The prescription of Semyung-Gangji-tang, designed for the treatment of hyperlipidemia and atherosclerosis, consists of herbs effective at treating blood stasis and phlegm stagnancy. It invigorates the liver, kidney and spleen. Its medical nature is not too cold or too hot and it increases human vital energy. The purpose of this study is to examine the currative effects of Semyung-Gangji-tang on hyperlipidemia in rabbits. Twenty-four male NZW rabbits, around 2kg of B.W., were divided into 3 groups. Group I was served as the normal group. Group II was served as the hyperlipidemic control group fed with 1 % cholesterol diet for 8weeks and with normal diet for the next 4weeks. Group III was served as the treatment group, treated the same as the control group and medicated with Semyung-Gangji-tang for the last 4weeks. Blood samples were collected from each of the animals at a, 3, 6, 8, 10, 12 weeks and used for the blood chemical analysis. Animals were sacrificed at 8 and 12weeks and chemical analyses were performed on the collected liver samples. The serum total cholesterol value of treatment group ($938.60{\pm}95.07{\;}mg/dl$) at l2weeks was significantly decreased (P<0.00l) compared with the value of control group ($1375{\pm}37.82{\;}mg/dl$) at 12weeks. The serum LDL-cholesterol value of the treatment group ($838.00{\pm}89.52 mg/dl$) at l2weeks was significantly decreased(p<0.00l) compared with the value of the control group ($1249.60{\pm}37.63{\;}mg/dl$) at l2weeks. These results indicate that Semyung-Gangji-tang has the effects of lowering serum lipid in experimentally induced hyperlipidemic rabbits.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.21 no.5
• /
• pp.33-39
• /
• 2021

In this study, we tried to find the correlation of the parameters and dual resonance of U-slot microstrip patch antenna with L-shaped Inset-feed structure and design broadband antenna using them. In the first step, we classified cases where dual resonance occurs through changes in antenna parameters that affect antenna performance. In the second step, we correlated each antenna parameter to the location and intensity of the resonance point, and 3 dB bandwidth. Next, antenna simulation confirmed the process of designing to have wide bandwidth using the correlation in the second step previously presented in the U-slot antenna case with narrow bandwidth. Finally, we fabricated a designed antenna and demonstrated the validity of antenna bandwidth broadening through the correlation analysis.

• International journal of advanced smart convergence
• /
• v.7 no.4
• /
• pp.50-56
• /
• 2018

The Internet of Things (IoT) and Visible Light Communication (VLC) is opening up new services in lighting industry by integrating sensory network features in addition to standard illumination functionality. In this progressive developments, the next generation lighting devices for smart homes are capable to sense the environmental conditions and transfer the captured data through lights to gateway controller to access remotely. The smart home environmental sensor information's are few kbps only so VLC systems need to built-in with low rate light connectivity to transfer data to the gateway. To provide error free communication, the quality of a received light signal is important to be considered when designing an VLC receiver. Therefore, this paper proposes the design of robust low rate IoL receiver design using NCP302 voltage detector for micro controller to adapt the IoT/IoL front end module for system integration. To evaluate the proposed system performance, the Arduino UNO based IoT/IoL controller designed with lighting, sensors and lights connectivity interfaces. The experimental result shows that the robust interference rejection is feasible on proposed VOL receiver and possible to have an error-free communication up to 10 kbps at a low SNR using OOK modulation.

• Journal of Korean Medicine for Obesity Research
• /
• v.20 no.2
• /
• pp.78-87
• /
• 2020

Objectives: To expand and provide information on the efficacy of herbal medicines, anti-obesity effects were evaluated. In many studies, plant-derived components with anti-obesity efficacies have been investigated for their potential inhibitory effects on 3T3-L1 preadipocyte cells. The purpose of this study was to investigate the anti-obesity effects of 65 herbal medicine in 3T3-L1 preadipocyte cells. Methods: Preferentially, 3T3-L1 cells were treated with 65 herbal medicines (500 ㎍/mL) during differentiation for 8 days. Next, 3T3-L1 cells were treated with selected herbal medicines at concentrations ranging from 50 to 200 ㎍/mL during differentiation for 8 days. The accumulation of lipid droplets was determined by Oil Red O staining. The expressions of genes related to adipogenesis were measured by reverse transcription polymerase chain reaction and Western blot analyses. Results: Among the 65 kinds of herbal medicines, 13 herbal medicines that been shown to be effective against the accumulation of lipid droplets were selected. Finally, selected Banhasasim-tang and Samhwangsasim-tang showed inhibitory activity on adipocyte differentiation at 3T3-L1 preadipocytes without affecting cell toxicity. In addition, Banhasasim-tang and Samhwangsasim-tang significantly reduced the expression levels of several adipocyte marker genes including peroxisome proliferator activated receptor-γ and CCAAT/enhancer binding protein-α. Conclusions : These results suggest that the ability of Banhasasim-tang and Samhwangsasimtang has inhibited overall adipogenesis and lipid accumulation in the 3T3-L1 cells. Banhasasim-tang and Samhwangsasim-tang may be a promising medicine for the treatment of obesity and related metabolic disorders.

• Journal of Korean Society of Environmental Engineers
• /
• v.35 no.1
• /
• pp.17-22
• /
• 2013

In this study, a pH control method by carbon dioxide ($CO_2$) was applied to coagulation process in water treatment plant (WTP) to investigate the coagulation efficiency and residual dissolved aluminum when high pH raw water is flowing into the plant during algal blooming. Existing coagulant dose (1 mg/L in raw water) resulted in the pH reduction of 0.0384 by LAS, 0.0254 by PAC, 0.0201 by A-PAC, and 0.0135 by PACS2, respectively. And then the concentration of dissolved aluminum was 0.02 mg/L at pH 7.44, 0.07 mg/L at pH 7.96, 0.12 mg/L at pH 8.16, 0.39 mg/L at pH 8.38 showing the concentration increase with pH in the coagulation process. It was noteworthy that rapid increase was observed at pH above 8.0 next the rapid mixing. Therefore it is necessarily required to control pH below 7.8 in the coagulation process in order to meet drinking water quality standard of aluminum for high pH raw water into WTP, $CO_2$ injection could control pH successfully at about 7.3 even for the raw water of high pH above 8.0. In addition it was found that the pH control by $CO_2$ injection was significantly effective for coagulation in terms of turbidity removal, coagulant dosage, and residual dissolved aluminum concentration.

• Journal of Plant Biotechnology
• /
• v.42 no.1
• /
• pp.49-54
• /
• 2015

Based on the results in this study, here we propose a systematic micropropagation process for 'Gisela 5' that is one of the important dwarfing cherry rootstocks. When the apical tips detached from newly developed shoot in spring season were cultured on the half strength MS media with 0.5 mg/L IBA and 0.5 ~ 1.0 mg/L BA, the cultures scored the highest acquisition rate at 90% for normal shoot with vigorous growth and without hyperhydricity. As next step, the young shoots maintained in vitro well multiplied on the full strength MS medium supplemented with 0.5 mg/L IBA and 0.5 mg/L BA, in which multiplication rate was approximately nine-fold. Given the half strength MS medium containing 2.0 mg/L IBA, each transplanted shoot further developed robust roots. Finally, the plantlets were easily acclimatized in the compost consisted of vermiculite, perlite, and peatmoss in the proportion of 1:1:1. We expect that the results are useful for cherry cultivation and its rootstock production.