• International Journal of Aeronautical and Space Sciences
• /
• v.15 no.4
• /
• pp.396-411
• /
• 2014

Synchronized switch damping (SSD) techniques have recently been developed for structural vibration control using piezoelectric materials. In these techniques, piezoelectric materials are bonded on the vibrating structure and shunted by a network of electrical elements. These piezoelectric materials are switched according to the amplitude of the excitation force to damp vibration. This paper presents a new SSD technique called 'synchronized switch damping on negative capacitance and adaptive voltage sources' (SSDNCAV). The technique combines the phenomenon of capacitance transient charging and electrical resonance to effectively dampen the structural vibration. Also, the problem of stability observed in the previous SSD techniques is effectively addressed by adapting the voltage on the piezoelectric patch according to the vibration amplitude of the structure. Analytical expressions of vibration attenuation at the resonance frequency are derived, and the effectiveness of this new technique is demonstrated, for the control of a resonant cantilever beam with bonded piezoelectric patches, by comparing with SSDI, SSDVenh, and SSDNC techniques. Theoretical predictions and experimental results show the remarkable vibration damping capability of SSDNCAV technique, which was better than the previous SSD techniques. The broadband vibration control capabilities of SSDNCAV technique are also demonstrated, which exceed those of previous SSD techniques.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.65 no.4
• /
• pp.285-291
• /
• 2016

A light-emitting diode (LED) has been increasingly applied to various industrial fields and general lightings because of its high efficiency, low power consumption, environment-friendly characteristic and long lifetime. To drive the LED lighting, a power converter with the constant output current is needed. Among many power converters, the flyback converter is chosen by many converter designers due to high power density, structural simplicity, and miniaturization. In this converter, an electrolytic capacitor is generally chosen for the stabilization of the DC voltage because of having the large capacitance and the low price. However, the disadvantages are the short expected life time and 120Hz ripple currents on the converter output node. In this paper, a single-stage dimmable PFC DCM flyback converter without the electrolytic capacitor is proposed to prolong the lifetime of the LED driver. For the long lifetime of the converter, the polyester film capacitor with the small capacitance is substituted for the electrolytic capacitor on the output node and an LC resonant filter is added to damp 120Hz ripple current. The proposed converter is verified through the simulation and the experimental works.

• Structural Engineering and Mechanics
• /
• v.32 no.4
• /
• pp.517-529
• /
• 2009

A passive vibration mitigation architecture is proposed to damp transverse vibrations of guyed masts. The scheme is based on a number of pendula attached to the mast and tuned to the vibration modes to be controlled. This scheme differs from the well-known autoparametric pendulum absorber system. The equations of motion of the guyed mast with an arbitrary number of pendula are obtained. The leading bending behaviour of a typical truss mast is described by an equivalent beam model whereas the guys are conveniently modeled as equivalent transverse springs whose stiffness comprises the elastic and geometric stiffness. By assuming a mast with an inertially and elastically isotropic cross-section, a planar model of the guyed mast is investigated. The linearization of the equations of motion of the mast subject to a harmonic distributed force leads to the transfer functions of the structure without the dampers and with the dampers. The transfer functions allow to investigate the mitigation effects of the pendula. By employing one pendulum only, tuned to the frequency of the lowest mode, the effectiveness of the passive vibration potential in reducing the motion and acceleration of the top section of the mast is demonstrated.

• Journal of agricultural medicine and community health
• /
• v.21 no.1
• /
• pp.13-20
• /
• 1996

Paederus dermatitis caused by the contact of staphylinid beetles(Paederus fuscipes) body fluid(pederin) is characterized by linear erythematous vesicopustular lesions. An outbreak of dermatitis occurred at apartments located at the river side after rainy season in summer 1994. Authors surveyed 189 cases(94 males and 95 females) from 103 households reported at the apartment office in Kimcheon on September 1994. The results are as follows; 1. The causative agent of skin diseases was identified as Paederus fuscipes. 2. The attack rate of paederus dermatitis was 52.6% by households, and the residents in the middle floors of the apartments were attacked more frequently than those in other floors. All ages were affected. 3. The skin lesions developed by paederus were distributed on face(38.2%), neck(18.5%), shoulder and trunk(11.0%), arm and leg(10.3%), and back(6.6%). In 21 cases(15.4%), skin lesions were developed in multiple sites. 4. The apartments attacked by paederus was located near the sand and damp soil along the bank of the river. The fodder cultivating farm was located near the upper reaches of river, and a rice field and grape garden in the backyard of the apartment.

• Journal of Korean Medical classics
• /
• v.21 no.4
• /
• pp.225-232
• /
• 2008

The purpose of this study is to introduce the music therapy as one of the 17 kinds of oriental medicine music therapy and investigate the record in the literature. The spleen is an organ that has the function of digestion, absorption, and supply of nutrition. Damp, anxiety, and improper diet can cause deficiency syndrome of the spleen. The symptoms of deficiency of the spleen are poor appetite, abdominal distension, borborygmus, water-grain dysentery, dyspepsia, and lack of strength in limbs. CV12, CV6, S36, B20, B21, and Sp4 are can be used as acupuncture points that are a great help to the patients who suffer from deficiency of the spleen. This study describes the theory of invigorating the spleen music therapy that has a good possibility as a new method of oriental medical treatment and present the acupuncture points that can be used with invigorating the spleen music therapy. The tone of the spleen is Gung(宮) and the sound of the spleen is related to a song. The music therapy of invigorating the spleen includes beating Earth-Gi(地氣) rhythm with Cheonnyeonmanse, stimulating Spleen Meridian and Stomach Meridian with Gayaguem sanjo jungjungmori, and acupuncture with "Le Cygne" of Camille Saint-Saens.

• Korean Journal of Acupuncture
• /
• v.22 no.3
• /
• pp.175-197
• /
• 2005

Objective : The purpose of this study is to review the acupuncture therapy and moxibustion on itching Method : We searched and reviewed chinese journals of and books of the acupuncture therapy and moxibustion on itching. Results & Conclusions : 1. Dermatopathy of itching is described as eczema, neurotic-dermititis, itching in orient medical text. 2. According to text, itching causes were wind symptom produced by deficiency of blood, deficiency syndrom of the spleen, and damp-heat. 3. Frequently used acupoints were LI10(41 frequency), SP10(29), ST36(27), SP6(22), GB20(19), Asi point(18), BL(17), back Su acupoints(13), LI4(13), SP9(10), PC6(7), HT7(7). etc 4. The practice of acupuncture was used by body acupuncture, auriculo-theraphy, loss of bleeding with needle, blum-blosson needle, dermal needle, fire needle. etc. 5. Moxibustions are mild moxibustion, non-scar producing moxibustion, herb- moxibustion. etc.

• Journal of the Korean Applied Science and Technology
• /
• v.18 no.4
• /
• pp.261-272
• /
• 2001

An ACR/HMMM film was prepared by blending high-solid ACR with curing agent, hexamethoxymethyl melamine (HMMM). An active curing reaction was observed at $170^{\circ}C$. The dynamic viscoelastic $T_{g}$ of the final film increased with the static viscoelastic $T_{g}$ of the film. The log damp value, which means a viscoelastic ratio, decreased with the increase in the curing temperature of the film. Physical properties of the films were within a suitable range for films, and by an accelerated weathering resistance test the films were proved weather resistible ones.

• Journal of Acupuncture Research
• /
• v.22 no.2
• /
• pp.103-110
• /
• 2005

Phellodendri Cortex (PC) has been used traditionally in Korea for damp heat leukorrhea with thick, yellow, discharge, foul-smelling diarrhea or dysentery. We investigated whether the Phellodendri Cortex Herbal-acupuncture Solution (PCHS) induced cell-death on SNU-17, human cervical cancer cell. 3-(4,5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay was performed to find out the cytotoxicity of PCHS. The cell death was identified as apoptosis from the results of 4, 6-diamidineo-2-phenylindole (DAPI) staining, terminal deoxy-nucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) assay. The expression of proapototic gene, Bax, was increased and the expression of apoptotic gene, Caspase-3, was also increased. Considering the above results, PCHS could induce the apoptosis on SNU-17, human cervical cancer cell, via Bax-related Caspase-3 activation. And it might provide the experimental data for the clinical use of Phellodendri Cortex on cervical cancer.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
• /
• v.18 no.3
• /
• pp.135-141
• /
• 2005

Hyperhidrosis of the palms and soles is a disorder characterized by excessive sweating that occurs in the hands and feet and that cause severe psychological, social and/or professional disability. The pathophysiological cause is still unknown but the condition is related to over-activity in the Sympathetic Nervous System. We experienced four young patients with hyperhidrosis of the palms and soles that was thought to be initiated by emotional distress, nervousness, stressful situation and anxiety. In the point of Differentiation of Syndrome, this subject was diagnosed as consumptive fever of the Heart and a weakness of the Spleen and damp heat, and was administrated with Yangshimtang-Gamibang. After treatment of herbal medicine and acupuncture, hyperhidrosis and other symptoms of patients were improved.

• Korean Journal of Microbiology
• /
• v.22 no.2
• /
• pp.103-110
• /
• 1984

The conditions for the protoplast fusion of auxotrophic mutants of Trichoderma koningii were determined. A preparation of commercial enzyme Driselase was used successfully to isolate protoplasts from the 18 hr old mycelium of T. koningii. The yields of protoplasts production were ranged from $0.3{\times}10^8$ to $2.5{\times}10^8$ protoplasts per mg of damp mycelium of various auxotrophic mutant strains. The regeneration frequencies from $9.3{\times}10^{-3}\;to\;2.0{\times}10^{-1}$ were obtained when the protoplasts from auxotrophic mutants were plated on the malt extract medium containing 0.6M $MgSO_4$, and 2% agar, and the optimal concentration of PEG for protoplst fusion was 30%. Exposure of protoplasts to PEG for 10 min was found to be sufficient to induce high frequency heterokaryon formation. Optimal pH of fusion mixture was determined as 5.5, and 1 mM of calcium chloride in fusion mixture was found to be sufficient to enhance protoplast fusion frequency. Under optimal condition, the fusion frequency of the cross between protoplasts from various auxotrophic mutants were $1.6{\times}10^{-2}\;and\;4.1{\times}10^{-2}$.