• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.11
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• pp.1613-1622
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• 2010

In this paper, the ultraprecision positioning control of an ultrasonic linear motor in a high-vacuum environment is presented. The bolt-clamped Langivin type transducer (BLT) with the 3rd longitudinal; and 6th lateral vibration modes was developed, which was excited by using the Eigen resonance frequency for two vibration modes in order to generate stable and high power. In practical applications, however, even if a geometrical design has an Eigen frequency, discordance between both mode frequencies can be generated by the contact mechanism and because of manufacturing errors as well as environmental factors. Both mode frequencies were precisely matched by adjusting the impedence. By using this method, the BLT can be driven under any environmental conditions. The nominal characteristic trajectory following(NCTF) control method was adopted to control the positioning of the system in vacuum. The developed linear motor stage show high positioning accuracy with 5 nm.

• Journal of Acupuncture Research
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• v.19 no.1
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• pp.175-188
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• 2002

Objective : The effects of SP6(Sanyinjiao, 三陰交) acupuncture stimulation on bladder parasympathetic nerve activity (PNA), tibial nerve activity (TNA) as well as blood pressure were examined in anesthetized rats and the results are as follows. Methods : The parasympathetic nerve leading to the bladder was exposed retroperitoneally, and the tibial nerve in the hindlimb was exposed through inguinal area. PNA and TNA were recorded using a bipolar platinum-iridium wire electrode and it was connected to preamplifier. Blood pressure was measured using cannula that was inserted into femoral artery and was recorded with blood pressure sensor that is connected with transducer amplifier. The mean value of all parameters measured for 30 seconds before the stimulation was expressed as 100%. An acupuncture needle was inserted into the SP6 region to a depth of 4 mm. Results : Under intact state (IS), acupuncture stimulation for 120 seconds induced significant increase of PNA which was accompanied with decrease of blood pressure. At the same time, TNA showed temporary increase only with acupuncture stimulation. In 4 mg/kg of naloxone-administrated state (NAS), significant decrease of PNA was seen and it was accompanied with increase of blood pressure. TNA also showed temporary increase only with acupuncture stimulation under the NAS just like the IS. Conclusion : consider that SP6(Sanyinjiao, 三陰交) acupuncture stimulation activated parasympathetic nerve and caused vasodilation to lead into the diuresis, but naloxone reversed the effect of acupuncture for antidiuresis.

• Journal of IKEEE
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• v.21 no.1
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• pp.66-69
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• 2017

In recent year, energy harvesting technologies from the ambient environments such as light, motion, wireless waves, and temperature again a lot of attraction form research community [1-5] due to its efficient solution in order to substitute for conventional power delivery methods, especially in wearable together with on-body applications. The drawbacks of battery-powered characteristic used in commodity applications lead to self-powered, long-lifetime circuit design. Thermoelectric generator, a solid-state sensor, is useful compared to the harvesting devices in order to enable self-sustained low-power applications. TEG based on the Seebeck effect is utilized to transfer thermal energy which is available with a temperature gradient into useful electrical energy. Depending on the temperature difference between two sides, amount of output power will be proportionally delivered. In this work, we illustrated a low-input voltage energy harvesting circuit applied discontinuous conduction mode (DCM) method for getting an adequate amount of energy from thermoelectric generator (TEG) for a specific wearable application. With a small temperature gradient harvested from human skin, the input voltage from the transducer is as low as 60mV, the proposed circuit, fabricated in a $0.6{\mu}m$ CMOS process, is capable of generating a regulated output voltage of 4.2V with an output power reaching to $40{\mu}W$. The proposed circuit is useful for powering energy to battery-less systems, such as wearable application devices.

• Journal of the Earthquake Engineering Society of Korea
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• v.24 no.5
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• pp.211-217
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• 2020

Earthquake preparedness has become more important with recent increase in the number of earthquakes in Korea, but many existing structures are not prepared for earthquakes. There are various types of liquefaction prevention method that can be applied, such as compaction, replacement, dewatering, and inhibition of shear strain. However, most of the liquefaction prevention methods are applied before construction, and it is important to find optimal methods that can be applied to existing structures and that have few effects on the environment, such as noise, vibration, and changes in underground water level. The purpose of this study is to estimate the correlation between the displacement of a structure and variations of pore water pressure on the ground in accordance with the depth of the sheet file when liquidation occurs. To achieve this, a shaking table test was performed for Joo-Mun-Jin standard sand and an earth pressure, accelerometer, pore water pressure transducer, and LVDT were installed in both the non-liquefiable layer and the liquefiable layer to measure the subsidence and excess pore water pressure in accordance with the time of each embedded depth. Then the results were analyzed. A comparison of the pore water pressure in accordance with Hsp/Hsl was shown to prevent lateral water flow at 1, 0.85 and confirmed that the pore water pressure increased. In addition, the relationship between Hsp/Hsl and subsidence was expressed as a trend line to calculate the expected settlement rate formula for the embedded depth ratio.

• The Journal of Advanced Prosthodontics
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• v.1 no.1
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• pp.31-36
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• 2009

PURPOSE. To determine the change in stability of single-stage, three different design of implant systems in humans utilizing resonance frequency analysis for early healing period(24 weeks), without loading. MATERIAL AND METHODS. Twenty-five patients were included into this study. A total of 45 implants, three different design of implant systems(group A,C,R) were placed in the posterior maxilla or mandible. The specific transducer for each implant system was used. ISQ(implant stability quotient) reading were obtained for each implant at the time of surgery, 3, 6, 8, 10, 12, 24 weeks postoperatively. Data were analyzed for different implant type, bone type, healing time, anatomical locations. RESULTS. For each implant system, a two-factor mixed-model ANOVA demonstrated that a significant effect on ISQ values(group A=0.0022, C=0.017, R=0.0018). For each implant system, in a two-factor mixed model ANOVA, and two-sample t-test, the main effect of jaw position(P > .005) on ISQ values were not significant. CONCLUSIONS. All the implant groups A, C and R, the change patterns of ISQ over time differed by bone type. Implant stability increased greatly between week 0 and week six and showed slow increase between week six and six months(plateau effect).

• The Journal of the Acoustical Society of Korea
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• v.16 no.1
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• pp.39-46
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• 1997

In this paper, the PA(PhotoAcoustic) signals excited in metals by Xef, KrF excimer laser pulse were detected by a PZT transducer, and its transforming machanism and directivity patterns were analysed. The laser energy density in irradiation spot divides the PA trasnsorming machanism to be classified into thermoelastic and plasma regime, and the transforming machanisms in two regimes are different from each other. Based on theoretical model, it is predicted that shear wave is greater than longitudinal in the thermoelastic regime and longitudinal is greater than shear wave by reaction force in plasma regime. These predictions were verified through experiments by using of the XeF excimer pulsed laser of 480nm center-wavelength and the KrF excimer pulsed laser of 248nm. Also, for its directivity pattern, an arrival angle of the maximum longitudinal energy was around $60^{\circ}$ and maximum shear energy was around $30^{\circ}$ in the thermoelastic regime, and an arrival angle of maximum longitudinal energy was shown on nomal to the surface and maximum shear energy was represented in about $30^{\circ}$ in plasma regime.

• The Journal of the Acoustical Society of Korea
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• v.30 no.2
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• pp.63-72
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• 2011

Since the detection probability is critically dependent on the target strength (TS) in active sonar and on the radiated noise level (RNL) in passive sonar, the acoustic materials for echo reduction (ER) and transmission loss (TL) are widely used for the stealth of underwater targets. In this paper, a measurement system based on the small water tank, for the frequency range of greater than 30 kHz, is developed and verified using reference targets. In order to design the water tank and the geometry of test samples, a program is developed to calculate the arrival time of interfering signals due to the reflection from water tank walls and also due to the diffraction from the edge of the test samples. Considering all the interfering signals, an optimal experimental configuration for water tank and test samples is designed and used throughout the experiment. Next, the signal processing algorithms to estimate ER and TL are developed based on the measured propagation loss reflecting the geometric spreading characteristics of the transducer. Finally, a set of reference targets such as aluminium plate and perfectly reflecting plate are used in a small water tank to verify the developed measurement system.

• Mycobiology
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• v.43 no.3
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• pp.319-326
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• 2015

Fomes fomentarius is a fungus of the Polyporaceae family and is used in traditional oriental therapies. Although the anti-inflammatory activities of this species have been previously reported, the identity of the bioactive compounds responsible for this activity remains unknown. Here, we investigated whether methyl 9-oxo-(10E,12E)-octadecadienoate (FF-8) purified from F. fomentarius exerts anti-inflammatory activity in murine macrophages stimulated with lipopolysaccharide (LPS). FF-8 suppressed secretion of nitric oxide (NO) and prostaglandin $E_2$ through downregulation of inducible NO synthase and cyclooxygenase-2 expression induced by LPS. In addition, pretreatment of cells with FF-8 led to a reduction in levels of secreted inflammatory cytokines such as tumor necrosis factor-${\alpha}$ and interleukin-6 in macrophages stimulated with LPS. Conversely, FF-8 did not affect nuclear factor ${\kappa}B$, p38, c-Jun NH2-terminal kinase, and extracellular signal-regulated kinase pathways. Instead, FF-8 specifically interfered with signal transducer and activator of transcription 3 (STAT3) phosphorylation induced by LPS. Collectively, this study demonstrated that FF-8 purified from F. fomentarius suppresses inflammatory responses in macrophages stimulated with LPS by inhibiting STAT3 activation. Further studies will be required to elucidate the anti-inflammatory effect of FF-8 in vivo.

• Journal of Korean Medicine for Obesity Research
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• v.20 no.1
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• pp.1-9
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• 2020

Objectives: Artemisinin and its derivatives extracted from Artemisia annua, a Chinese herbal medicine, have variable biological effects due to structural differences. Up to date, the anti-obesity effect of dihydroartemisinin (DHA), a derivative of artemisinin, is unknown. The purpose of this study was to investigate the anti-adipogenic and lipolytic effects of DHA on 3T3-L1 preadipocytes. Methods: Oil Red O staining and AdipoRed assay were used to measure lipid accumulation and triglyceride (TG) content in 3T3-L1 cells, respectively. Cell count analysis was used to determine the cytotoxicity of 3T3-L1 cells. Western blot and real-time reverse transcription polymerase chain reaction analyses were used to analyze the expression of protein and mRNA in 3T3-L1 cells, respectively. Results: DHA at 5 μM markedly inhibited lipid accumulation and reduced TG content in differentiating 3T3-L1 cells with no cytotoxicity. Furthermore, DHA at 5 μM inhibited the expression of CCAAT/enhancer-binding protein-α (C/EBP-α), peroxisome proliferator-activated receptor-γ (PPAR-γ), fatty acid synthase (FAS), and perilipin A as well as the phosphorylation of signal transducer and activator of transcription-3 (STAT-3) in differentiating 3T3-L1 cells. Moreover, while DHA at 5 μM had no effect on the mRNA expression of adiponectin, it strongly suppressed that of leptin in differentiating 3T3-L1 cells. However, DHA at 5 μM had no lipolytic effect on differentiated 3T3-L1 cells, as assessed by no enhancement of glycerol release. Conclusions: These results demonstrate that DHA at 5 μM has a strong anti-adipogenic effect on differentiating 3T3-L1 cells through the reduced expression and phosphorylation of C/EBP-α, PPAR-γ, FAS, perilipin A, and STAT-3.

• The Korean Journal of Physiology
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• v.11 no.2
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• pp.33-39
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• 1977

It has been reported that administration of Ginseng powder to the Guinea pig reduces anaphylactic shook induced by horse serum (Lee, 1939). However, Lee et al. (1960) and Paik et al. (1976) have demonstrated that Ginseng increases capillary permeabilites and histamine release from the mast cell. These facts suggest that Ginseng acts directly on the bronchial muscle causing it to dilate. Recently, a number of investigators(Kidakawa & Iwasiro 1963; Takagi et al. 1973) have reported that Ginseng reverses acetylcholine- or histamine- induced contraction in the isolated Guinea pig ileum. We, therefore, undertook the present study to examine if Ginseng relaxes the spasm of bronchial muscle induced by acetylcholine or histamine. We have also attempted to identify the mechanism of the Ginseng effect. Male Guinea Pig was sacrificed by a blow on the head, The trachea was removed and sectioned with scissors into about 12 rings. After the 'C' shaped ring of cartilage was sectioned the one end of ring was tied to the bottom of the incubation bath and the other end was connected to a force transducer (FTO 3C) to record tension on a Polygraph. When the antispasmodic action of Ginseng effect was first examined in the normal trachea which was not treated by the drug. And then the Ginseng effect was tested in the muscle treated by histamine hydrochloride, acetylcholine hydrochloride or barium chloride. The results indicate that Ginseng alcohol extract relaxes the contraction of isolated tracheal muscle induced by histamine $(1{\mu}g/ml{\sim}10{\mu}g/ml)$, acetylcholine $(1{\mu}g/ml{\sim}5{\mu}g/ml)$ and barium chloride (1.5 mg/ml). The mechanism of this action is in Pa.1 due to nonspecific antimuscarinic and antihistaminic effect and in part by predominant action in the adrenergic ${\beta}-receptor$ although the ${\alpha}-receptor$ is also involved. We, therefore, conclude that Ginseng can be act as a bronchodilator.