• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
• /
• pp.152-152
• /
• 2008

Micro probe with Ni-Co tip was designed. Unit processes for fabricating the micro probe were developed. We are investigated the micro probe tip using by Ni-Co alloy. One-step and three-step needle was fabricated by plating process, CMP, and photolithography process. The plating thickness was varied by current density and time. Futher data will be extract by different process conditions.

• 전기의세계
• /
• 제26권3호
• /
• pp.69-72
• /
• 1977

The effects of sharpness of needle electode on the spark voltage in needle-plane and needle-needle spark gaps at atmospheric pressure was investigated experimentaly in this paper. As the sharpness of needle electrode increases, the spark voltage increases, and the rate of increase is greater in needle-needle electrode than in needle-plane gap. the effects of sharpness is greater in small gap length. These characteristics can be explained by the electric field strength at the needle tip depending on the sharpness of needle, electro-static capacity between the electrodes, and the polarity effect in needle-plane gap. These experimental results will be able to play an important roles on the design of needle-needle gap as high voltage measurement devices and of needle-plane gap as high voltage rectifier equipments.

• Journal of Mechanical Science and Technology
• /
• 제19권5호
• /
• pp.1194-1205
• /
• 2005

The common-rail injection systems, as a new diesel injection system for passenger car, have more degrees of freedom in controlling both the injection timing and injection rate with the high pressure. In this study, a piezo-driven injector was applied to a high pressure common-rail type fuel injection system for the control capability of the high pressure injector's needle and firstly examined the piezo-electric characteristics of a piezo-driven injector. Also in order to analyze the effect of injector's needle response driven by different driving method on the injection, we investigated the diesel spray characteristics in a constant volume chamber pressurized by nitrogen gas for two injectors, a solenoid-driven injector and a piezo-driven injector, both equipped with the same injection nozzle with sac type and 5-injection hole. The experimental method for spray visualization was based on back-light photography technique by utilizing a high speed framing camera. The macroscopic spray propagation was geometrically measured and characterized in term of the spray tip penetration, spray cone angle and spray tip speed. For the evaluation of the needle response of the above two injectors, we indirectly estimated the needle's behavior with an accelerometer and injection rate measurement employing Bosch's method was conducted. The experimental results show that the spray tip penetrations of piezo­driven injector were longer, on the whole, than that of the solenoid-driven injector. Besides we found that the piezo-driven injector have a higher injection flow rate by a fast needle response and it was possible to control the injection rate slope in piezo-driven injector by altering the induced current.

• 한국한의학연구원논문집
• /
• 제18권3호
• /
• pp.87-93
• /
• 2012

Objectives : The present study is to verify whether the deformation of ear acupuncture needle tips that are currently on the market is caused during the process of initial packaging. Methods : Ear acupuncture needles distributed from three different companies were collected to measure the size of the groove on the transparent plate which is used in for the intial packaging. Then the tolerance range for off-centered tips, which represent the range of the groove size that is safe from damaging the needle tip, was determined based on the vertical length measured from tip to handle. 200 ear acupuncture needles were dipped in alcohol and scanned to confirm the position of the needles. Stereo-microscope was used to observe the needle tips that were located outside the tolerance range. Results : The increased number of ear acupuncture needle tips placed outside the tolerance range were seen from in the order of C company, A company and B company. The increased deformation of the needle tips caused by initial packaging was observed in the order of A company, C company and B company. Conclusion : Only the ear acupuncture needles from B company showed the strong correlation between needle tip deformation and initial packaging. It has been observed that the deformation of the ear acupuncture needles is mainly due to manufacturing process, not the packaging process.

• 조명전기설비학회논문지
• /
• 제29권11호
• /
• pp.74-81
• /
• 2015

In the measurement of atmospheric static electric field, it is important to know characteristics of corona discharges caused at the tip of test electrode. This paper presents the fundamental data of DC corona discharges that occurred at the tip of a needle-shaped electrode placed in the homogeneous background electric field which simulates the atmospheric static field under thundercloud. The major characteristics of interest for this purpose are the polarity effect of corona discharges and the magnitudes and time intervals of corona current pulses. The experimental set-up consists of the plate-to-plate configuration with a needle-shaped protrusion, DC power supply, and voltage and current measuring devices. As a result of experiments, the polarity dependence of corona pulses is significantly pronounced. The time intervals between successive corona pulses in the negative polarity is much longer than those in the positive polarity. The time intervals for both polarities is drastically decreased as the applied electric field is increased. Also the magnitudes of the positive corona pulses are slightly changed with an increase in applied electric field, but those of the negative corona pulses are linearly increased with increasing the applied electric fields.

• Journal of Advanced Marine Engineering and Technology
• /
• 제30권3호
• /
• pp.351-358
• /
• 2006

The capability of high pressure injection with small fuel quantify at all engine operating conditions is one of the main feature in common rail fuel injection system, which is used in small and light-duty Diesel engine. The key parameter for the better atomized fuel sprays and multiple injections of this common rail fuel injection control, that can be freely selected irrespective of the engine speed and load is the mechanism controlling the needle energizing and movement in high pressure Diesel injector. In the electro-hydraulic injector, the injection nozzle is being opened and closed by movement of the injector's needle which is balanced by pressure between the nozzle seat and the needle control chamber. This study describes the macroscopic spray structure characteristics of the common rail Diesel injectors with different electric driving method i.e. the solenoid-driven and piezo-driven type. The macroscopic spray characteristics such as spray tip speed. spray tip penetration and spray cone angle were investigated by the high speed spray, which is measured by the back diffusion light illumination method with optical system for the high speed temporal photography in a constant volume chamber pressurized by nitrogen gas. As the results, the prototype piezo-driven injector system was designed and fabricated for the first time in domestic case and the effect of injector's needle response driven by different drive type was compared between the solenoid and piezo-driven injector It was found therefore. that the piezo-driven injector showed faster needle response and had better needle control capability by altering the electric input value than the solenoid-driven injector.

• Clinical Endoscopy
• /
• 제51권6호
• /
• pp.576-583
• /
• 2018

Background/Aims: Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) remains the most common EUS-guided tissue acquisition technique. This study aimed to evaluate the performance of a new Franseen tip fine needle biopsy (FNB) device for EUSguided sampling of solid lesions and compare it with the historical FNA technique. Methods: $Acquire^{(R)}$ 22 G FNB needle (Boston Scientific Co., Natick, MA, USA) was used for solid tumor sampling (Study group). Tissue was collected for rapid on-site evaluation, and touch and crush preparations were made. Historical EUS-FNA samples obtained using $Expect^{(R)}$ 22 G FNA needle (Boston Scientific Co.) were used as controls (Control group). All specimens were independently evaluated by two cytopathologists blinded to the formal cytopathological diagnosis. Results: Mean cell block histology scores were significantly higher (p=0.046) in the FNB group (51 samples) despite a significantly lower (p<0.001) mean number of passes compared to the FNA group (50 specimens). The overall diagnostic yields for the FNB vs. FNA groups were 96% vs. 88%. The degree of tumor differentiation was adequately assessed in all cell block qualifying lesions in the FNB group. Two patients developed post-FNB abdominal pain. Conclusions: The new Franseen tip FNB device provides histologically superior and cytologically comparable specimens to those obtained by FNA, but with fewer passes.

• 대한방사선협회지
• /
• 제30권1호
• /
• pp.58-62
• /
• 2004

The purpose of this study was to determine the factors influencing on the size of Radiofrequency ablation using an internally cooled needle electrodes in cattle liver. Ablation procedures involved the use of cool-tip RF system generator and internally coo

• Korean Journal of Acupuncture
• /
• 제23권4호
• /
• pp.85-99
• /
• 2006

Objectives : Proper acupuncture stimulation is associated with a characteristic set of sensation usually referred to as 'De-Qi'. In order to develop the appropriate sham acupuncture, various sensations to each stimulation should be considered through analysis of the profiles of acupuncture sensation. It was therefore investigated to compare the acupuncture sensation scale (ASS) of two types of sham acupuncture to that of the real acupuncture. Methods : Ninety-four participants (mean age 26.4, range 26-49) were asked to complete five point-Likert scale ASS developed by Vincent et al. after real or two-kinds of sham acupuncture stimulation: blunted tip sham acupuncture (BT) and round tip sham acupuncture (RT). Needling was done at LI4 acupoint on non-dominant hand and stimulated for 30 seconds with real or two-kinds of sham needle. Finger withdrawal latency (FWL) of each group was also measured to evaluate the pain sensitivity to noxious heat stimuli. Results : BT acupuncture significantly less produced penetrating, numb, intense, hurting, pulling, shock, tingling, throbbing sensation than real acupuncture stimulation. RT acupuncture significantly less produced penetrating, burning, electric, numb, intense, hurting, pulling, aching, shasharp, shock, stinging, tingling, throbbing sensation than real acupuncture. Each group did not demonstrate the differences of pain sensitivity to noxious stimuli. Conclusions : These results indicated that types of tip of acupuncture produced different kinds of acupuncture sensation. Our finding provides a general information of sensations to two kinds of sham acupuncture for development of ideal placebo sham needle.

• 한국표면공학회지
• /
• 제31권1호
• /
• pp.45-53
• /
• 1998

Sharp tips are commonly used for applications in fields as diverse as nanolithography, lowvoltage field emitters, emitters, nanoelectroniecs, electrochemisty, cell biology, field-ion and electron microscopy. tungsten wire, mater만 used in this experiment, which test the chip of wafer has been used to the needle of probe card. Tungsten wire was sharpened by electrochemical etching methode to get a typical tip shape.