• The Journal of the Acoustical Society of Korea
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• v.43 no.2
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• pp.168-177
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• 2024

When designing an underwater Piezoelectric Energy Harvester (PEH), Vortex Induced Vibration (VIV) is generated throughout the cantilever through a change in curvature, and the generation of VIV increases the vibration displacement of the curved cantilever PEH, which is an important factor in increasing actual power. The material of the curved PEH selected a Polyvinyline Di-Floride (PVDF) piezoelectric film, and the flow velocity is set at 0.1 m/s to 0.50 m/s for 50 mm, 130 mm, and 210 mm with various curvatures. The strain energy change of PEH by VIV was observed. The smaller the radius of curvature, the larger the VIV, and as the flow rate increased, more VIV appeared. Rapid shape transformation due to the small curvature was effective in generating VIV, and strain energy, normalized voltage, average power, etc. To increase the amount of power of the PEH, it is considered that the average power will increase as the number of curved PEHs increases as well as the steep curvature is improved.

• Journal of Yeungnam Medical Science
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• v.33 no.1
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• pp.72-75
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• 2016

Pulmonary epithelioid hemangioendothelioma (PEH) is a rare, low-to-intermediate malignant tumor of endothelial origin. Computed tomography (CT) findings of PEH demonstrate multiple small bilateral nodules; however, to the best of our knowledge, there were no reports on PEH coexisting with other malignancies. Here, we reported on a case involving PEH in a patient with colon cancer and breast cancer which was misconceived as pulmonary meta- stasis. A 63-year-old woman who suffered from constipation for 2 weeks visited our hospital. Colonoscopy showed a large mass with obstruction on hepatic flexure. The histological diagnosis was adenocarcinoma of the ascending colon. Multiple nodules in both lungs and breast were observed on a chest CT scan. A core biopsy of a breast nodule was performed and a diagnosis of invasive ductal carcinoma of the left breast was made. Pulmonary nodules observed on the chest CT scan was considered as pulmonary metastasis from colon or breast cancer. Laparoscopic right hemicolectomy was performed. At the same time, wedge resection of the lung was performed and pathological diagnosis was PEH. Radiologic features of PEH were difficult to distinguish from lung metastasis. Therefore the author reported a rare case involving PEH in a patient with primary malignancy of colon and breast.

• Smart Structures and Systems
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• v.10 no.1
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• pp.33-46
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• 2012

To reduce the vibration of cable-stayed bridges, conventional magnetorheological (MR) damper control system (CMRDS), with separate power supply, sensors and controllers, is widely investigated. In this paper, to improve the reliability and performance of the control system, one adaptive MR damper control system (AMRDS) consisting of MR damper and piezoelectric energy harvester (PEH) is proposed. According to piezoelectric effect, PEH can produce energy for powering MR damper. The energy is proportional to the product of the cable displacement and velocity. Due to the damping force changing with the energy, the new system can be adjustable to reduce the cable vibration. Compared with CMRDS, the new system is structurally simplified, replacing external sensor, power supply and controller with PEH. In the paper, taking the N26 cable of Shandong Binzhou Yellow River Bridge as example, the design method for the whole AMRDS is given, and simple formulas for PEH are derived. To verify the effectiveness of the proposed adaptive control system, the performance is compared with active control case and simple Bang-Bang semi-active control case. It is shown that AMRDS is better than simple Bang-Bang semi-active control case, and still needed to be improved in comparison with active control case.

• Korean Journal of Materials Research
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• v.29 no.6
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• pp.371-377
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• 2019

A flexible piezoelectric energy harvester(f-PEH) that converts tiny mechanical and vibrational energy resources into electric signals without any restraints is drawing attention as a self-powered source to operate flexible electronic systems. In particular, the nanocomposites-based f-PEHs fabricated by a simple and low-cost spin-coating method show a mechanically stable and high output performance compared to only piezoelectric polymers or perovskite thin films. Here, the non-piezoelectric polymer matrix of the nanocomposite-based f-PEH is replaced by a P(VDF-TrFE) piezoelectric polymer to improve the output performance generated from the f-PEH. The piezoelectric hybrid nanocomposite is produced by distributing the perovskite PZT nanoparticles inside the piezoelectric elastomer; subsequently, the piezoelectric hybrid material is spin-coated onto a thin metal substrate to achieve a nanocomposite-based f-PEH. A fabricated energy device after a two-step poling process shows a maximum output voltage of 9.4 V and a current of 160 nA under repeated mechanical bending. Finite element analysis(FEA) simulation results support the experimental results.

• Archives of Plastic Surgery
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• v.43 no.3
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• pp.284-287
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• 2016

Epithelioid hemangioendothelioma (EHE) is a well-differentiated and rare vascular tumor. Systemic metastases are uncommon. Herein, we present a patient with skin metastasis of pulmonary EHE (PEH) that was treated by wide excision. A 76-year-old male was evaluated due to pulmonary thromboembolism and a solitary pulmonary nodule. A biopsy was performed and pathological examination of the mass confirmed EHE. No metastasis was observed. The patient returned to care approximately two years later due to a painful nodule in the right lower leg. A skin biopsy showed metastatic EHE from the lung. We used a safety margin of 1 cm based on clinical experience, because no prior case had been reported regarding the resection margin appropriate for primary cutaneous EHE and skin metastases of PEH. At four months after surgery, the patient recovered without complications or recurrence. Skin metastasis of PEH is extremely rare, and only two cases have been reported in the literature. In this case, we report a rare case of PEH with histologically diagnosed skin metastasis that was successfully treated by curative resection. It is expected that this case report will provide a helpful contribution to the extant data regarding PEH metastases.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.76-77
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• 2009

This paper is concerned with the development of the piezoelectric energy harvesting(PEH) device using Wind. In this study, the piezoelectric energy harvesting system consisting of a cantilever with a pinwheel and piezoelectric wafer was investigated in detail both theoretically and experimentally. The power output characteristics of the PEH was then calculated and discussed. Theoretical and experimental results showed that the PEH was able to charge a battery with ambient vibrations but still needed an effective mechanism which can convert mechanical energy to electrical energy and an optimal electric circuit which dissipates small energy.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.4
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• pp.659-667
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• 2004

Plantain has been used for antidiarrhea, antihemorrhage and the remedy of indigestion. Plantain was extracted with ethanol and fractionated systemically with n-hexane, chloroform, ethylacetate (EtOAC) and n-butanol. Antioxidant index (AI was expressed as induction period of oil containing various fractions/induction period of oil of 600 ppm) of EtOAC fraction was the highest among fractions in vitro. The protective effects of the EtOAC fraction of plantain (PE) administered 1 mL orally or intraduodenally on experimentally induced gastritis, gastric ulcer and gastric secretion were evaluated in rats. Sprague-Dawley rats weighing 250∼300 g were divided into 4 groups; negative control group (CON), PE 200 mg/kg treated group (PEL), PE 400 mg/kg treated group (PEH) and positive control group (cimetidine 100 mg/kg-CMT or omeprazol 100 mg/kg treated group-OMT), respectively, PE significantly suppressed HCl-ethanol induced gastric lesions and indomethacin-induced gastric ulcers (administered subcutaneouly) in rats. Specially PE 400 mg/kg showed significantly inhibitory effect, which was more potent than that of 100 mg/kg of commercial drug, cimetidine, and elevated an inhibitory effect to be close to the level in inhibitory ratio of omeprazol administered group in Shay's ucler. On gastric secretion in pylorus ligated rat, PE 200 mg/kg and 400 mg/kg decreased the gastric volume and acid output, but did not show an apparent effect on pepsin activity. In addition, PE 400 mg/kg depressed gastric ulcers induced by water immersion stress and duodenal ulcers induced by cysteamine administered subcutaneouly. These results suggest that the ethylacetate fraction of plantain can be used in prevention and treatment of experimentally induced gastric mucosal damage and ulcers.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.7
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• pp.554-558
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• 2011

Piezoelectric energy harvester (PEH) as a box type was fabricated in order to harvest mechanical energy imparted to roadways from passing vehicles and convert it into electricity. The PEH was composed of 72 piezoelectric cantilevers with 9 springs with elasticity stick to a bottom of the PEH. For the single piezoelectric cantilever, when a single push with approximately 5 mm displacement was incident to it, power of 0.355 mW was produced at $100\;k{\Omega}$. It is found that the power from the single piezoelectric cantilever increases when spring constant is high. We investigated power of PEH when the moving vehicle passes in it. Power was increased with increasing vehicle speed. When vehicle speed is 30 km/h, power is 20.6 mW.

• Tuberculosis and Respiratory Diseases
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• v.51 no.5
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• pp.466-473
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• 2001

Pulmonary epithelioid hemangioendothelioma (PEH), originally termed an intravacular bronchioloalveolar tumor, is a rare pulmonary neoplasm with a vascular origin and slow rate of malignancy. It affects various organs such as the liver, the central nervous system, lung, etc. Clinically, pulmonary epithelioid hemangioendothelioma has been considered to be a borderline malignancy, a generally indolent and nonaggressive tumor that displaces the pulmonary parenchyma over a number of years by slowly enlarging the tumor nodule. The clinical course of PEH is known to be usually benign. Here we report an unusual case of PEH that was highly malignant and was eventually fatal. The PEH was confirmed by microscopic analysis and immunohistochemical staining of CD31+(a membrane receptor and a sensitive and specific marker for vascular lesions) from an open lung biopsy specimen.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.6
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• pp.546-552
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• 2013

A cantilevered piezoelectric energy harvester(PEH) and an auxiliary mass-spring unit can be integrated into a novel two-degrees-of-freedom PEH where its lowest eigenmode is not an in-phase modes but an out-of-phase mode. This typical behavior was shown to enhance output power considerably compared with its stand-alone counterpart. The objective of this study is to newly develop a continuum-based mathematical model suitable for efficient analysis of the mode-sequence reversed PEH. Once such a mathematical model is available, various physical behaviors can be analytically investigated for better designs. After a new mathematical model is developed, its validity is checked by using ANSYS results, in terms of resonant frequency, open-circuit voltage, and output power with a specified external resistance.