• Journal of Sensor Science and Technology
• /
• v.24 no.1
• /
• 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.

• The Korean Journal of Pain
• /
• v.12 no.1
• /
• pp.128-131
• /
• 1999

Stellate ganglion block is a well established method for the management of certain pain syndromes (e.g., chronic regional pain syndrome, facial pain) in the cervicothoracic region and upper extremity. The stellate ganglion resides between the C7 transverse process and the head of the first rib. Anesthetic injections for the stellate ganglion block are typically made at the level of the transverse process of either the C6 or C7 vertebrae to avoid the pleura, vessels, and nerve roots. Method of positioning the needle tip directly at the ganglion has been described, but are problematic because of the risk of injury to or injection into adjacent structures. It is necessary to know the exact anatomic position of the stellate ganglion when permanent blockade is required by means of radiofrequency thermocoagulation. Whereas fluroscopy shows only bony feature, computerized tomography also images nerves, vessels, and lung, allowing accruate needle placement. We report a case of the percutaneous radiofrequency thermocoagulation of the stellate ganglion after computerized tomography-guided localization.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1997.11a
• /
• pp.313-316
• /
• 1997

The effects of aromatic curing agent of MDA contents and post curing conditions on dielectric deterioration characteristics of DGEBA/MDA/SN system were investigated. The dielectric properties were measured by using needle-plane electrode geometry under the commercial AC high electric field application. As the curing agent content increased, the dielectric breakdown strength increased and then decreased slightly. All the trees initiated from the tip of needle electrode and the shape of the tree in this system was a dendrite type.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
• /
• v.32 no.4
• /
• pp.162-166
• /
• 2019

Objectives : This report is intended to suggest that lentigo can be removed using the cauterization. Methods : Handle of the needle, which is distal part to the tip and shaft, was heated with an alcohol lamp to cauterize the lentigo one by one to form a crust, and wet dressing was applied to the treatment sites by using Hwangryunhaedok-tang pharmacopuncture solution. Results : Ten days after the cauterization, the lentigo was cleared from the normal skin without adverse reactions. Conclusions : The cauterization is a useful technique for removing lentigo, but the conventional method is somewhat inconvenient, so a radiofrequency technique or a laser-based cauterization may be more useful Instead of the traditional cauterization.

• The Korean Journal of Pain
• /
• v.25 no.3
• /
• pp.183-187
• /
• 2012

The use of fluoroscopy guidance together with the loss of resistance technique during epidural injections has been advocated lately; moreover, epidural injections in the absence of fluoroscopic guidance have a high rate of inaccurate needle-tip placement during the injections. However, the approach to the lower cervical and upper thoracic epidural space may be challenging due to its obscure lateral fluoroscopic views from overlying normal tissue structures. In this case, we report an alternative oblique C-arm fluoroscopy guided view approach to supplement the standard anterior-posterior and lateral fluoroscopic views to facilitate successful needle placement and precise anatomical localization of the epidural space.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.22 no.2
• /
• pp.128-133
• /
• 2008

This paper describes underwater discharge phenomena and breakdown characteristics in case that the standard lightning impulse voltage is injected to the needle and spherical electrodes installed in the hemisphere water tank. The objective of this work is to understand the basic features related to transient ground impedance against lightning surges. The discharge luminous images were observed and the dependence of breakdown voltage on the polarity of applied voltage and water resistivity were investigated. As a consequence, streamer corona is initiated at the tip of needle and spherical electrodes and is propagated toward grounded tank with stepwise extension. The breakdown voltage characteristics measured as a function of water resistivity showed V-shaped curves. Breakdown voltage and time curve of needle electrode is higher than that of spherical electrode.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2008.11a
• /
• pp.269-272
• /
• 2008

Internal flow field of supersonic nozzle with pintle, which control thrust of solid rocket motor, is very complicated by pintle tip shape and contour of nozzle. For studying of pintle nozzle performance by effects of internal flow field variation with pintle position, cold flow test and numerical analysis about needle type pintle shape were performed and results were presented in this paper. As the results of this study, three types of internal shocks exists in the pintle nozzle and oblique shock is oscillated by pintle position

• Restorative Dentistry and Endodontics
• /
• v.43 no.1
• /
• pp.2.1-2.10
• /
• 2018

Objectives: To determine the effect of size and insertion depth of irrigation needle on the amount of apical extruded debris and the amount of penetration depth of sealer using a confocal laser scanning microscope (CLSM). Materials and Methods: Twenty maxillary premolars were assigned to 2 groups (n = 10), according to the size of needle tip, 28 G or 30 G. Buccal roots of samples were irrigated with respective needle type inserted 1 mm short of the working length (WL), while palatal roots were irrigated with respective needle type inserted 3 mm short of the WL. Prepared teeth were removed from the pre-weighed Eppendorf tubes. Canals were filled with F3 gutta-percha cone and rhodamine B dye-labeled AH 26 sealer. Teeth were transversally sectioned at 1 and 3 mm levels from the apex and observed under a CLSM. Eppendorf tubes were incubated to evaporate the irrigant and were weighed again. The difference between pre- and post-weights was calculated, and statistical evaluation was performed. Results: Inserting needles closer to the apex and using needles with wider diameters were associated with significantly more debris extrusion (p < 0.05). The position of needles and level of sections had statistically significant effects on sealer penetration depth (p < 0.05 for both). Conclusions: Following preparation, inserting narrower needles compatible with the final apical diameter of the prepared root canal at 3 mm short of WL during final irrigation might prevent debris extrusion and improve sealer penetration in the apical third.

• Proceedings of the KOR-BRONCHOESO Conference
• /
• 1976.06a
• /
• pp.85.2-85
• /
• 1976

Harford has pointed out that the application of impedance audiometry in the Eustachian tube function is of special value. As you know, with excessive negative pressure in the middle ear cavity with intact eardrum tympanograms reveal indirect evidence of Eustachian tube insufficiency. With normal Eustachian tube function eardrum should be pushed laterally by Valsalva maneuver, resulting in a temporary decrease in the compliance of the system, indicated by a swing of the balance meter needle. Therefore the authors measured the swing of the balance meter needle by the Valsalva maneuver in persons with intact eardrums, intact middle ear cavities, and intact Eustachian tube function. The results are as follows; The swing of the eardrum by Valsalva maneuver is 1.0 to 4.0 (mean $1.6{\pm}0.06$) and we conclude that the persons under 1.0 of the swing is suggestive of some disfunctions of the Eustachian tube.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2011.11a
• /
• pp.662-665
• /
• 2011

Pintle technology, which is one of the thrust control method for solid rocket motor, can control the thrust by the control of nozzle throat area through the pintle moving. For studying the unsteady flow characteristics of pintle nozzle by needle type pintle moving, cold flow test and numerical analysis were performed. The pressure distribution on the pintle tip was varied for pintle moving and stopping and thrust was varied by this effects.