• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.10
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• pp.917-925
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• 2016

Schmitt Trigger logic is a gate level design method to have hysteresis characteristics to improve noise immunity in digital circuits. Dynamic Threshold voltage MOS(DTMOS) Schmitt trigger circuits can improve noise immunity without adding additional transistors but by controlling substrate bias. The performance of DTMOS Schmitt trigger logic has not been verified yet in standard CMOS process through measurement. In this paper, DTMOS Schmitt trigger logic was implemented and verified using Magna $0.18{\mu}m$ MPW process. DTMOS Schmitt trigger buffer, inverter, NAND, NOR and simple digital logic circuits were made for our verification. Hysteresis characteristics, power consumption, and delay were measured and compared with common CMOS logic gates. EM Immunity enhancement was verified through Direct Power Injection(DPI) noise immunity test method. DTMOS Schmitt trigger logics fabricated using CMOS process showed a significantly improved EM Immunity in 10 M~1 GHz frequency range.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.10
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• pp.5980-5987
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• 2014

As a response to exhaust gas regulations, the electronic control system was applied to the diesel engine. The injected fuel mass and injection timing are accurately controlled using it, and the fuel efficiency and the engine output are significantly increased. In addition, the noise and the vibration of vehicles are decreased. To maintain the optimal performance of an electronic control diesel engine, it is important to control the fuel injection pressure accurately using the fuel pressure regulator. When the fuel pressure regulator is not worked normally, the failure phenomena (starting failure, staring delay, accelerated failure, engine mismatch et al.) occurred because the fuel pressure is not stabilized and controlled accurately. In this study, the effects on a fuel pressure, return fuel mass flow, and engine rotating speed according to the control rate of fuel pressure regulator were investigated to analyze the performance variation under the failure conditions of a fuel pressure regulator. As a result, when the control rate of a fuel pressure regulator decreased by 4%~6% compared to that of the standard condition, the variation of engine rotating speed and return fuel flow were increased greatly, and the abnormal condition occurred. In addition, it is possible to diagnose the failure of a fuel pressure regulator by monitoring these conditions.

• Advances in materials Research
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• v.13 no.3
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• pp.233-241
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• 2024

Quantitative analysis of the Zingiber Officinale sample using subcritical water extraction (SWE) was developed employing High-Performance Liquid Chromatography (HPLC) to bolster the advancement of this innovative green extraction process. This research focuses on three principal ginger bioactive compounds: 6-gingerol, 6-shagoal, and 10-gingerol. Various stages were undertaken to establish the quantitative analysis method, encompassing the optimisation of HPLC operating conditions and the formulation of standard calibration curves, yielding individual compound equations. A robust correlation within the calibration curve was achieved, exhibiting an r² value of 0.9814 and an RSD of 5.00%. A simultaneous, swift, and dependable method was established with an injection time of 20 minutes and an 8-minute delay between injections, in contrast to the previous HPLC analysis requiring a 45-minute injection time for detecting and quantifying all components. Notably, no post-treatment was applied after the SWE process. This advancement allows for potential future online measurement of Zingiber Officinale bioactive compounds extracted using subcritical water extraction through this technology.

• International Journal of Automotive Technology
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• v.8 no.4
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• pp.437-444
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• 2007

This paper experimentally investigates the effects of oxygen-enriched air (OEA) on the running behaviors of an LPG SI engine during both start/warm-up (SW) and hot idling (HI) stages. The experiments were performed on an air-cooled, single-cylinder, 4-stroke, LPG SI engine with an electronic fuel injection system and an electrically-heated oxygen sensor. OEA containing 23% and 25% oxygen (by volume) was supplied for the experiments. The throttle position was fixed at that of idle condition. A fueling strategy was used as following: the fuel injection pulse width (FIPW) in the first cycle of injection was set 5.05 ms, and 2.6 ms in the subsequent cycles till the achieving of closed-loop control. In closed-loop mode, the FIPW was adjusted by the ECU in terms of the oxygen sensor feedback. Instantaneous engine speed, cylinder pressure, engine-out time-resolved HC, CO and NOx emissions and excess air coefficient (EAC) were measured and compared to the intake air baseline (ambient air, 21% oxygen). The results show that during SW stage, with the increase in the oxygen concentration in the intake air, the EAC of the mixture is much closer to the stoichiometric one and more oxygen is made available for oxidation, which results in evidently-improved combustion. The ignition in the first firing cycle starts earlier and peak pressure and maximum heat release rate both notably increase. The maximum engine speed is elevated and HC and CO emissions are reduced considerably. The percent reductions in HC emissions are about 48% and 68% in CO emissions about 52% and 78%; with 23% and 25% OEA, respectively, compared to ambient air. During HI stage, with OEA, the fuel amount per cycle increases due to closed-loop control, the engine speed rises, and speed stability is improved. The HC emissions notably decrease: about 60% and 80% with 23% and 25% OEA, respectively, compared to ambient air. The CO emissions remain at the same low level as with ambient air. During both SW and HI stages, intake air oxygen enrichment causes the delay of spark timing and the increased NOx emissions.

• Journal of Embryo Transfer
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• v.27 no.3
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• pp.141-147
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• 2012

This study was operated to establish induction using ultrasonography by estimating the relation of follicle size and estrus manifestation. Clinical estrus symptoms were observed 97.4% in cows and 87.5% in heifers when overall 55 cows were induced to estrus in a single dose of $PGF_{2{\alpha}}$ after verifying CL through ultrasonography, which means estrus hours among those 52 cows showing the clinical estrus symptoms were estimated 2.39 days on cows and for 2.37 days on heifers which showed no differences (p>0.05). The estrus manifestation hours according to the follicle size in cows didn't have any significance each other (p>0.05), though estrus hours was 54 hours (the shortest) with follicle size bigger than 10 mm and were made up within 69 hours. The estrus manifestation hours according to the follicle size in heifers didn't have any significance each other (p>0.05) and took around 42 hours (the shortest) with follicle size of 5mm (the smallest) and were made up within 66 hours. Follicles after $PGF_{2{\alpha}}$ injection were ovulated and assigned to many phases as follows; Group 1 (growing phase) - continuously growing into ovulation, Group 2 (growing and static phase) - delaying in growth after the growth of follicles, Group 3 (static and growing phase) - growing after growth delay, Group 4 (regressing and new growing phase) - the follicle is closed and a new follicle grows. In addition, the process of follicle development and estrus hours had no significance each other (p>0.05), though estrus manifestation hours in Group 1 and 2 was relatively short, and in Group 3 and 4 for a relatively long time. In the result of all above, the estrus manifestation hours after $PGF_{2{\alpha}}$ injection has no differences accoring to the follicle size in cows and heifers. Therefore, High pregnancy rate is obtained when practicing artificial insemination within 3 days in estrus or TAI in 72 to 80 hours after adminitrating $PGF_{2{\alpha}}$.

• The Korean Journal of Zoology
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• v.23 no.4
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• pp.229-238
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• 1980

The present experiment was carried out to observe the effect of Korean ginseng extract on the blood picture of mice that have been infected with Sarcoma-180. The observation of standard group was made for 2 days, 7 days, 12 days, 15 days after the injection of Sarcoma-180 and the observation of ginseng extract group was made at 15 days after the injection of Sarcoma-180 and simultaneously with oral adminstration of ginseng extract every day for 15 days. 1. For 15 days after the injection of Sarcoma-180 in the standard group, the numbers of R.B.C. and platlet were not changed significantly, but the number of W.B.C. increased at the first stage, and then decreased suddenly after the middle stage. However, the number of W.B.C. was not severely decreased in the ginseng extract group. This phenomenon is estimated that ginseng extract assisted for W.B.C. to protect living body. 2. Serum protein picture of standard group was appeared as a nonselective protein losing pattern, and ginseng extract group was likely that of standard group, but it was not severe than that of standard group. This phenomenon is believed that ginseng extract gave some delay or immunization for Sarcoma-180 mouse against the development of Sarcoma-180. 3. Serum cholesterol quantities of standard group increased gradually until middle stage, but decreased in the last stage. But serum cholesterol quantity of ginseng extract group showed a slight increase. What the decrease of cholesterol quantity in the last stage of standard group is caused especially by the decreased intaking of feed among many causes, it may be the cause of intaking not decrease of feed in ginseng extract group, as the ginseng extract gave the Sarcoma-180 mouse some resistance against the development of Sarcoma-180. 4. Along with developing of Asrcoma-180 in the standard group, serum total lipid quantities increased, and $\\alpha-, \\beta$-lipoprotein quantities showed decrease phenomenon, but pre $\\beta$-lipoprotein quantities increased rapidly. The value of ginseng extract group was appeared the value in the first stage of standard group. This phenomenon was also estimated that ginseng extract protected the living body according to above theories, and that ginseng extract gave the Sarcoma-180 mouse some resistance against the development of Sarcoma-180.

• The Journal of Internal Korean Medicine
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• v.43 no.4
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• pp.625-642
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• 2022

Objectives: Postoperative ileus (POI) is a common impairment of gastrointestinal motility and causes a delay in postoperative recovery, as well as an increased length of hospital stay, but no single strategy has a significant recuperative effect on POI. Studies of traditional Korean medicine (TKM) have reported improvements in bowel function after surgery. The aim of this systematic review was to assess the effectiveness of TKM on postoperative ileus in gastric cancer patients. Methods: We used six databases to search for studies published from January 1, 2007, until May 11, 2022. The included studies were those reporting gastric cancer patients who received TKM treatment after gastrectomy through indicators related to POI. Results: The search identified 27 RCTs that used herbal medicine (Daegeonjung-tang and Gami-leejoongtang), herbal medicine combined with acupuncture (Sama-tang, Gumiseunggi-tang, Daeseunggi-tang, and Insam-tang), acupuncture, acupuncture and moxibustion, electroacupuncture, warm needling, transcutaneous electroacupuncture (TEA), low-frequency electrical acupoint stimulation (LEAS), moxibustion, auricular acupressure, and ST-36 acupoint injection with neostigmine as treatments for POI. The time to first flatus was shortened by herbal medicine combined with warm needling (Sama-tang, Gumiseunggi-tang, Daeseunggi-tang, and Insam-tang), acupuncture, electroacupuncture, warm needling, TEA, moxibustion, auricular acupressure, and ST-36 acupoint injection with neostigmine (p<0.00001). The time to the first defecation decreased significantly in response to the herbal medicine combined with warm needling (Sama-tang, Gumiseunggi-tang, Daeseunggi-tang, and Insam-tang), acupuncture, electroacupuncture, warm needling, TEA, moxibustion, auricular acupressure, and ST-36 acupoint injection with neostigmine (p<0.00001). No serious adverse events occurred. Conclusions: TKM could be a promising option for preventing and resolving POI in gastric cancer patients after gastrectomy.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2009-2014
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• 2007

Hydrogen is a fuel of fuel cell system, which has powerful explosion possibility. Hence, the fuel cell system needs safety evaluation to prevent risk of hydrogen leakage. We use a actual size chamber of a common fuel cell module to analyze hydrogen. Hydrogen injection holes are located in lower part of the chamber in order to simulated hydrogen leakage. The hydrogen sensor can detect range of 0${\sim}$4%. Since the hydrogen gas, of which leaked amount is controled by MFC, are injected at the bottom holes, the transient sensor signals are measured. At a condition of 10cc/s of hydrogen leakage, the sensor detects hydrogen leakage after 22sec and there is also several seconds of time delay depending on the position of the sensor. This experimental data can be applied for the design of the hydrogen detection system and ventilation system of a residential fuel cell system.

• Geomechanics and Engineering
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• v.12 no.5
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• pp.803-813
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• 2017

This study discussed the possible optimization of enzyme-mediated calcite precipitation (EMCP) as a soil-improvement technique. Magnesium chloride was added to the injection solution to delay the reaction rate and to improve the homogenous distribution of precipitated minerals within soil sample. Soil specimens were prepared in 1-m PVC cylinders and treated with the obtained solutions composed of urease, urea, calcium, and magnesium chloride, and the mineral distribution within the sand specimens was examined. The effects of the precipitated minerals on the mechanical and hydraulic properties were evaluated by unconfined compressive strength (UCS) and permeability tests, respectively. The addition of magnesium was found to be effective in delaying the reaction rate by more than one hour. The uniform distribution of the precipitated minerals within a 1-m sand column was obtained when 0.1 mol/L and 0.4 mol/L of magnesium and calcium, respectively, were injected. The strength increased gradually as the mineral content was further increased. The permeability test results showed that the hydraulic conductivity was approximately constant in the presence of a 6% mineral mass. Thus, it was revealed that it is possible to control the strength of treated sand by adjusting the amount of precipitated minerals.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.6
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• pp.98-104
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• 2010

An experimental investigation was conducted to analyze the effects of EGR ratio on the combustion, exhaust emissions characteristics and size distributions of particulate matter in a single cylinder diesel engine with common-rail injection system fueled with biodiesel derived from soybean. In order to analyze the combustion, exhaust emissions and measurement of size distributions of particulate matter were carried out under various EGR ratio which was varied from 20~60% and the results were compared to those of results without EGR. The experimental results show that ignition delay was extended and maximum value of rate of heat release (ROHR) was decreased according to increasing of EGR ratio. In addition, oxidies of nitrogen ($NO_x$) emissions were reduced but soot emissions were increased under increasing of EGR ratio. However, under higher EGR ratio region, soot was slightly decreased. And then the particulate size distribution shows that high exhaust gas temperature restrain the formation of soluble organic fraction (SOF) which were beyond the accumulation mode (100~300nm) and lead to increase of nuclei mode particles.