Hoseong Kim

Electric Field Energy Harvesting Powered Wireless Sensors for Smart Grid

In this paper, a new energy harvesting technology using stray electric field of an electric power line is presented. It is found that energy can be harvested and stored in the storage capacitor that is connected to a cylindrical aluminum foil wrapped around a commercial insulated 220 V power line. The average current flowing into 47 µF storage capacitor is about 4.53 µA with 60 cm long cylindrical aluminum foil, and it is possible to operate wireless sensor node to transmit RF data every 42 seconds. The harvested average power is about 47 µW in this case. Since the energy can be harvested without removing insulating sheath, it is believed that the proposed harvesting technology can be applied to power the sensor nodes in wireless ubiquitous sensor network and smart grid system.

A randomized, observer-blinded, comparison of combined 1064-nm Q-switched neodymium-doped yttrium-aluminium-garnet laser plus 30% glycolic acid peel vs. laser monotherapy to treat melasma.

Background.  Melasma is a common pigmentary disorder that poses therapeutic challenges. Mixed‐type melasma usually does not respond to conventional monotherapy.

Zero standby power remote control system using light power transmission

All commercial remotely controllable home appliances consume electric power while in standby mode waiting for a remote signal. This paper presents a new remote control system that consumes absolute zero power in standby mode. In this system, the home appliance is physically disconnected from the AC power line by a latch-type power relay in standby mode. When a laser beam is emitted from a remote controller to turn on the home appliance, the photovoltaic array mounted on the home appliance receives and accumulates the light energy in a storage capacitor. An autonomous connection circuit is devised and used to separate the storage capacitor from the power relay to prevent discharge during the light energy accumulation stage. When the proposed remote control system is implemented on a 190 W commercial television, use of a 15 mW infrared (830 nm) laser light for 620 ms turns it on at a distance of 2 m in a completely dark room. It can then be turned off using commercial remote controller1.

Comparative study of hyaluronic acid fillers by in vitro and in vivo testing

Numerous hyaluronic acid (HA) fillers seem to have similar characteristics, although manufacturers insist that monophasic and biphasic HA fillers are different in many ways. Little information regarding this is available in the literature.

A laser-based 2-dimesional angular deflection measurement system for tilting microplates

A laser-based system that is capable of measuring the angular deflection of the microplate in two-dimension is developed. The system consists of a HeNe laser, lenses, beamsplitters, objective lens, CCD camera and position sensitive photodiode. The operation of the system is based on the measurement of the displacement of a HeNe laser beam reflecting off the surface of the microplate using position sensitive photodiode. The angular resolution is estimated at 0.2° and the response time of the system is as short as 4 μs. This system can measure the static and dynamic angular response and resonance frequency of microplates, such as spatial light modulators and micromirrors, in two orthogonal directions.

Unusual presentation of onychomycosis caused by Exophiala (Wangiella) dermatitidis

The phaeohyphomycoses are a heterogeneous group of rare mycotic infections caused by dematiaceous fungi that are widely distributed in the environment. Phaeohyphomycosis is usually an opportunistic infection in immunosuppressed patients or can be associated with chronic diseases and diabetes. Rarely, immunocompetent patients may be affected. We report an unusual presentation of onychomycosis caused by Exophiala (formerly Wangiella) dermatitidis in a healthy man, a circumstance that has rarely been mentioned in the literature previously. A 42-year-old man presented with an 1-year history of linear longitudinal ridging with yellowish pigmentation on the nail of the right great toe (Fig. 1). The other nails were normal, as was the skin of the soles and interdigital webs. The patient was in good health with normal laboratory findings, and had no history of trauma or nail abnormalities before the present lesion. Scrapings were collected from the nail plate and hyperkeratotic areas. Direct microscopic examination of the samples in 40% potassium hydroxide mounts showed hyphae, conidiophores and yeast cells. The hyphae were sparse, septate and olivaceous. The ellipsoidal conidia measured 3–4 · 2–3 lm. The scrapings were cultured on Sabouraud dextrose agar at 25 C. Repeated cultures taken from the nail plates all yielded similar findings, growing grey-black, velvety colonies (Fig. 2a). Slide cultures were stained with lactophenol cotton blue, and showed elliptic or conic-shaped conidia on the upper areas or lateral walls of the hyphae (Fig. 2b). A nail biopsy was taken, and the tissue cultured for fungi. On histological examination, hyperkeratosis, parakeratosis and acanthosis were seen, which stained positive for periodic-acid–Schiff. Irregularly branching septate hyphae and budding yeast-like cells were visible, although there was no inflammatory cell infiltration (Fig. 2c). Based on the morphological tests, we diagnosed the patient with onychomycosis due to E. dermatitidis. He was given pulse therapy with oral itraconazole (400 mg daily for 1 week followed by no medication for 3 weeks) for 6 months. The symptoms gradually improved, and fungal elements were not detected at the end of the treatment. The dematiaceous (brown-pigmented) fungi are a large and heterogenous group of moulds that cause a wide range of diseases including phaeohyphomycosis,

Monolithic fabrication of optical benches and scanning mirror using silicon bulk micromachining

This paper details an optical scanning mirror with a 54.74? inclined reflective plane and optical benches to align the optical components simply in a monolithic silicon substrate so as to implement a miniaturized laser scanner. The scanning mirror was designed and fabricated to achieve laser scanning on a miniaturized scale so that fluorescence detection of arrays of patterns on biochips can be performed by a handheld system. The inclined (1?1?1) reflective plane of the scanning mirror was formed by the KOH wet etching process, and proved to be a very appropriate structure for the assembly of optical scanning systems composed of a laser input and a scanning mirror in a silicon substrate. The optical benches, torsion spring and comb electrodes were fabricated using the DRIE process. The scanning mirror is actuated by its moment of inertia, the electrostatic torque of the comb electrodes and the restoring torque of the torsion spring. As designed, the scanning mirror is 2165 ? 778 ?m2 in an upper part of the rotor of the mirror, and the chip size including optical bench guides is 9 ? 10 ? 1 mm3. The deflection angle of the scanning mirror was measured by a laser displacement meter (LC2420, Keyence, Japan), and the optical components were assembled and aligned in optical bench guides to observe the laser scanning. The deflection angle of the scanning mirror depends on matching the frequency of the driving signal and the mechanical oscillation of the scanning mirror, and a maximum deflection angle of ?7? was obtained when a 16 V peak?peak square wave was applied to the comb electrodes. The scanning mirror with an inclined reflective plane and optical benches fabricated in a monolithic silicon substrate was proved to be a smart structure to implement a handheld-type scanning system for biochip application.

Fabrication and deflection measurement of micromirrors supported by an S-shape girder

Micromirrors supported by S-shape girders were fabricated and their angular deflections were measured using a laser- based system. A micromirror consists of a 50 micrometers X 50 micrometers aluminum plate, posts and an S-shape girder. Two electrodes were deposited on two corners of the substrate beneath the mirror plate. 50 X 50 micromirror array were fabricated using the Al-MEMS process. The electrostatic force caused by the voltage difference between the mirror plate and one of the electrodes causes the plate to tilt under the girder touches substrate. Bias voltage of the mirror plate is between 25 approximately 35 V and signal pulse voltage on the electrodes is 5 V. A laser-based system capable of real-time two-dimensional measurements of the angular deflection of the micromirror was developed. The operation of the system is based on measuring the displacement of a HeNe laser beam reflecting off the micromirror. The resonance frequency of the micromirror is 50 kHz when the girder touches the substrate and it is 25 kHz when the micromirror goes back to flat position, since the moving mass is about twice of the former case. The measurement results also revealed that the micromirror slants to the other direction even after the girder touches the substrate.

Small bowel ischemia after angiographic embolization for angiodysplasia of lower gastrointestinal tract: The case for conservative management

However, transarterial embolization for angiodysplasia has become widely used, the possibility of complications such as bowel ischemia and infarction still exists. We experienced a 60-year-old woman of small bowel ischemia after angiographic embolization for the angiodysplasia of cecum treated with conservative management. We should consider the possibility of recovery via the rich intramural vascular networks of the lower GI tract before deciding to operate.

Micro-Electro-Mechanical System/Field-Effect-Transistor Hybrid Switch for Energy Scavenging System

An innovative micro-electro-mechanical system/metal–oxide–semiconductor field-effect-transistor (MEMS/MOSFET) hybrid switch is presented. The main switch of the hybrid device is a MOSFET switch whose gate voltage is supplied through a MEMS switch. The electrostatic operation mechanism and inherent hysteresis characteristics of MEMS switch combined with the characteristics of MOSFET provides a high current handling capability, a low power consumption, self-referencing, a high noise immunity, and an ease of control and all of these advantages are experimentally demonstrated in practical circuits. This hybrid switch can be employed in energy scavenging system and in other electronic devices in order to save standby energy.