• Bulletin of the Korean Chemical Society
• /
• 제35권11호
• /
• pp.3209-3212
• /
• 2014

This paper describes a selective synthetic method of fabricating Ag nanowires by using a modified polyol process. To synthesize the Ag nanowire, an ethylene glycolic solution of silver nitrate and an ethylene glycolic solution of polyvinylpyrrolidone solution containing a small amount of organic oxidant, 1,4-benzoquinone, were slowly added to a hot ethylene glycol medium at $160^{\circ}C$ for 8 min using a syringe pump. The reaction mixtures were heated for an additional 45 min and cooled to room temperature. Finally, the silver nanomaterials were isolated from the mixture by centrifugation. The crystal structure of the nanomaterials was investigated by powder X-ray diffraction analyses, and their morphology was investigated by scanning electron microscopy. A small amount of organic oxidant, 1,4-benzoquinone, played a significant role in controlling the morphology during crystal growth. Consequently, Ag nanowires rather than Ag nanoparticles were selectively obtained.

• 한국환경과학회지
• /
• 제13권1호
• /
• pp.41-45
• /
• 2004

In this study, The decomposition of gas-phase Benzene and Toluene, Xylene in air streams by direct UV Photolysis, UV/TiO$_2$ and UV/TiO$_2$/A.C process was studied. The experiments were carried out under various UV light intensities and initial concentrations of B.T.X to investigate and compare the removal efficiency of the pollutant. B.T.X was determined by GC-FID of gas samples taken from the a glass sampling bulb which was located at reactor inlet and outlet by gas-tight syringe. From this study, the results indicate that UV/TiO$_2$/A.C system (photooxidation-photocatalytic oxidation-adsorption process) is ideal for treatment of B.T.X from the small workplace. Although the results needs more verifications, the methodology seems to be reasonable and can be applied for various workplace (laundry, gas station et al.).

• 유체기계공업학회:학술대회논문집
• /
• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
• /
• pp.305-308
• /
• 2006

For controlling micro-flows inside a LOC (lab-on-a-chip) a syringe pump or an electronic device for EOF(electro-osmotic flow) have been used in general. However, these devices are so large and heavy that they are burdensome in the development of a portable micro-TAS (total analysis system). In this study, a new flow control system employing pressure chambers, digital switches and speed controllers was developed. This system could effectively control the micro-scale flows inside a LOC without any mechanical actuators or electronic devices We also checked the feasibility of this new control system by applying it to a LOC of micro-mixer type. Performance tests show that the developed control system has very good performance. Because the flow rate in LOC is controlled easily by throttling the speed controller, the flows in complicate microchannels network can be also controlled precisely.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2002년도 학술대회지
• /
• pp.699-702
• /
• 2002

Shunt valves implanted in the subcutaneous tissue of brain to treat patient with hydrocephalus were numerically simulated to investigate influence of pressure pulsation on their flow control characteristics. Shunt valves are subjected to pressure variation since ventricles enclosing the brain are under pressure pulsation rather than uniform pressure due to blood pressure variation. We modeled flow orifice through shunt valve and imposed pulsating pressure and valve diaphragm movement to compute flow through the valve. The results of our study indicated that flow rate increased by $40{\%}$ by introducing pressure pulsation and diaphragm movement on the shunt valve. Our results demonstrate the pressure-flow control characteristics of shunt valves unplanted above human brain may be quite different from the characteristics obtained by syringe pump test with uniform pressure and no diaphragm movement.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2002년도 학술대회지
• /
• pp.423-426
• /
• 2002

A custom micro-PIV optics assembly has been used to measure the flow field inside a T-shaped microchannel. The micro-PIV system consists of microscope objectives of various magnifications, a dichroic cube, and an 8-bit CCD camera. Fluorescent particles of diameters 620nm have been used with a Nd:YAG laser and color filters. A programmable syringe pump with Teflon tubings were used to inject particle-seeded distilled water into the channel at flow rates of $420,\;40,\;60{\mu}L/hr$. The microchannels are fabricated with PDMS with a silicon mold, then $O_2-ion$ bonded onto a slide glass. Results show differences in flow characteristics and resolution according to fluid injection rates, and magnifications, respectively. The results show PIV results with vector-to-vector distances of $2{\mu}m$ with 32 pixel-square interrogation windows at $50{\%}$ overlap.

• 대한기계학회논문집B
• /
• 제30권1호
• /
• pp.48-56
• /
• 2006

We investigated gas residence time and mixing characteristics due to various swirl numbers generated by normal injection of secondary air to a lab-scale cylinderical combustor. The residence time was estimated by measuring the temporal pressure difference which was caused by deposition of test particles on a filter media after the injection by a syringe. The mixing characteristics were evaluated by standard deviation value of test gas concentration at different measuring points. The test gas concentration was detected by a gas analyzer. The swirl number of $20{\sim}30$ for ${\theta}=5^{\circ}$ caused long residence time enough to improve mixing characteristics. Numerical calculations were also carried out to understand physical meanings of the experimental results.

• 한국가시화정보학회지
• /
• 제11권3호
• /
• pp.12-16
• /
• 2013

The impact and spreading behaviors of silicon dioxide nanoparticle colloidal suspension droplets were quantitatively visualized using a high-speed imaging system. Millimeter-scale droplets were generated by a syringe pump and a needle. Droplets of different velocity were impacted on a non-porous solid surface. Images were consecutively recorded using a CMOS high-speed camera at 5000 fps (frames per second) for millimeter-scale droplets. Temporal variations of droplet diameter, velocity and maximum spreading diameters were evaluated from the sequential images captured for each experimental condition. Effects of Reynolds number, Weber number, and particle concentration were investigated experimentally.

• 한국콘텐츠학회:학술대회논문집
• /
• 한국콘텐츠학회 2014년도 추계 종합학술대회 논문집
• /
• pp.431-432
• /
• 2014

본 연구는 핵의학과에서 사용하는 $^{99m}Tc$에서 방출되는 광자에너지에 대하여 거리에 따른 인체에 대한 선량당량을 평가하였다. 그 결과 주사기 차폐기구 유무에 따라 선량당량이 차이를 보였으며, 심부선량은 차폐를 하지 않은 경우 평균 $216.026{\mu}Gy/h$, 1 mm 텅스텐 차폐를 하였을 경우 평균 $4.240{\mu}Gy/h$, 2 mm 텅스텐의 경우 평균 0.124 uGy/h의 선량을 보였다. 이에 따라 주사기 차폐기구를 필수적으로 사용하여야 하며 종사자 개개인의 피폭 관리에 항상 유념하여야 한다. 또한 본 연구결과를 바탕으로 종사자의 피폭 감소 방안에 대한 연구가 지속적으로 이루어 져야할 것으로 생각된다.

• 대한약침학회지
• /
• 제1권1호
• /
• pp.87-102
• /
• 1997

YAKCHIM is a clinical research of korean O.M.D's in the 1960's, and it was activated by experimental research and organization of the association after 1980. YAKCHIM in Korea is a new technical therapy that used the efficacy of traditional herb and the stimulation of meridian at points by needles. In order to search the original form of YAKCHIM and the significance of development in therapeutic methodology, reger to various documents. The results were obtained as follow : 1. The form of injection in YAKCHIM is a developed form of a aspirator which trace the cupping therapy(附缸) to its origin. 2. The injection techniques that used extracts of oriental herb can be found out original methodology in Bee-acupuncture(蜂針) and snake teeth etc. that have been used in far-eastern area from long time ago. 3. YAKCHIM in Korea is a developed form of techniques which was combined with the meridian theory, in consequence, it is difference with an injection syringe which only used to injection in modern medicine.

• 센서학회지
• /
• 제24권1호
• /
• pp.35-40
• /
• 2015

Electrospinning method has easy preparation of nanofibers with a simple and versatile technique. Electrospun nanofiber is widely used by the simple approach and have great potentials in the numerous applicaitons of medicine, photonics, catalysts, sensors, etc. including advantage of their specific characteristics such as large surface to volume ratio. This paper focused on the fabrication of cobalt electrospun nanofibrer for applications such as electronic, optical and mechanical devices by metal based material. We fabricated cobalt nanofibers on aluminum foil by an electrospinning method. The electrospinning process was performed at a high voltage, 8 kV. The distance between the needle tip and the solution surface in the bath was 5 cm. The PVB - cobalt based nitrate solution was filled in a 10 mL syringe connected to a 22 gauge needle. We confirmed electrospun cobalt nanofiber after annealing process by SIMS (Secondary Ion Mass Spectrometry) analysis. The concept design, fabrication and results of mapping measurements are reported.