• Journal of the Korean Society for Precision Engineering
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• v.19 no.8
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• pp.180-186
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• 2002

Hot Plate is the major unit that it used to remove damp of wafer surface, to strength adhesion of photoresist (PR) and to bake coated PR in FAB process of semiconductor. The badness of Hot Plate (HP) has directly influence upon the performance of wafer, it is necessary to guarantee the performance of HP. In this study, a reliability evaluation system has been designed and developed, which is to measure and to estimate thermal uniformity and flatness of HP in range of temperature 0~$250^\circC$. This system has included the techniques which measures and analyzes thermal uniformity using infrared thermal vision, and which compensates measuring error of flatness using laser displacement sensor For measuring flatness, a measurement stage of 3 axes are developed which adapts the precision encoder. The allowable error of this system in respect of thermal uniformity is less $than\pm0.1^\circC$ and in respect of flatness is less $than\pm$1mm . It is expected that the developed system can measure from $\Phi200mm\;(wafer 8＂)\;to\;\Phi300mm$ (wafer 12＂) and also can be used in performance test of the Cool Plate and industrial heater, etc.

• Journal of Environmental Health Sciences
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• v.14 no.1
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• pp.23-32
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• 1988

A study was carried out to find distribution of Legionella spp. in hot water supplying systems of buildings in Seoul. Water samples were taken from the hot water taps in three research institute buildings during the period from the 2nd to 27th February, 1987. And all of the three buildings were supplied with hot water from the same central hot water tank. GVPC BCYEa and blood agar were used for the isolation of Legionella pneurnophila and slide agglutination test (SAT) was performed to identify their strain types. Main findings were as follows 1. 44 samples taken from hot tap-water revealed 20% of positive culture and 44 samples taken from hot water spouts revealed 11% of positive culture. 2. The 78% of positive samples taken from hot water was obtained from 25.1$\circ$C~45.0$\circ$C temperature range. 3. Only, Legionella pneumophila serogroup 3 was identified and most of them has been than 2$\mu$m in length. 4. The densities of the Legionella pneurnophila isolated from hot water samples were within the range of $1.0\times 10^2$ to $1.1\times 10^3$ CFU/l and their densities isolated from hot water spouts were either 1 CFU/plate or 2 CFU/plate.

• Current Photovoltaic Research
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• v.5 no.3
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• pp.83-88
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• 2017

The growth of intermetallic compounds is an important factor in the reliability of solar cells. Especially, the temperature change in the soldering process greatly affects the thickness of the intermetallic compound layer. In this study, we investigated the intermetallic compound growth by Sn-diffusion in solder joints of solar cells. The thickness of the intermetallic compound layer was analyzed by IR lamp power and hot plate temperature control, and the correlation between the intermetallic compound layer and the adhesive strength was confirmed by a $90^{\circ}$ peel test. In order to investigate the growth of the intermetallic compound layer during isothermal aging, the growth of the intermetallic compound layer was analyzed at $85^{\circ}C$ and 85% for 500 h. In addition, the activation energy of Sn was calculated. The diffusion coefficient of the intermetallic compound layer was simulated and compared with experimental results to predict the long-term reliability.

• Journal of Mechanical Science and Technology
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• v.17 no.3
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• pp.400-408
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• 2003

A study on the progressive inelastic deformation behavior of the 316 L stainless steel cylindrical structure with plate-to-shell junction under moving temperature front was carried out by structural test and analysis. The structural test intends to simulate the thermal ratcheting behavior occurring at the reactor baffle of the liquid metal reactor as free surface of hot sodium pool moves up and down under plant transients. The thermal ratchet load that heats the specimen up to 550$^{\circ}C$ was applied repeatedly and residual deformation was measured. The thermal ratcheting test was carried out with two types of cylindrical structures, one with plate to-shell junction and the other without the junction to investigate the effects of the geometric discontinuities on the global ratcheting deformation. The temperature distributions of the test specimens were measured and were used for the ratcheting analysis. The ratchet deformations were analyzed with the constitutive equation of the non-linear combined hardening model. The analysis results were in good agreement with those of the structural tests.

• Journal of Acupuncture Research
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• v.36 no.3
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• pp.147-153
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• 2019

Background: The aim of this study was to investigate the safety and analgesic effects of Datura Flos pharmacopuncture (DFP). Methods: The analgesic effects of DFP were assessed using mechanical (hot plate), chemical (formalin test), and thermal (von Frey filament test) pain tests. Forty male Sprague Dawley rats were assigned randomly into DFP (75 mg/kg, 150 mg/kg), lidocaine 0.5%, or normal saline group for treatment on Kl3. Gross pathology, histopathology, biochemistry and hematology were performed. Results: In the hot plate test, DFP at a high dose (HDDFP; 150 mg/kg) produced a significant analgesic effect, at 10 and 20-minutes post injection (p < 0.01). Low dose DFP (LDDFP; 75 mg/kg) also showed an analgesic effect at 10 minutes post injection (p < 0.01). In the formalin test, HDDFP produced an analgesic effect, for 0-10 and 10-20 minutes (p < 0.01) post treatment, whereas LDDFP showed analgesic effects between 10-20 minutes (p < 0.05). In the von Frey filament test, DF-H produced an analgesic effect, 10 (p < 0.01) and 20 minutes post treatment (p < 0.05). LDDFP showed analgesic effect at 10 minutes (p < 0.05). In the acupuncture response test, HDDFP produced an analgesic effect at 10 minutes post treatment (p < 0.05). DF-H did not cause any anatomical changes to the liver or kidney and there were no abnormalities in biochemistry or hematology. Conclusion: DF-H was not toxic and provided short term analgesia, suggesting it may be useful in the management of pain.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.6
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• pp.1919-1932
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• 1991

Experimental studies are conducted to investigate the Flow-Induced Vibration mechanism for cantilever plate model with the angle of attack (.alpha.=10.deg., 20.deg., 30.deg.). Research is divided into two parts. First, the flow fields around two dimensional flat plate model are investigated using LDV system. Second, the vortex shedding frequency and response spectra of cantilever plate are obtained experimentally using gap sensor and hot wire anemometer. Finite element method program was used in order to predict the flow field and pressure field around thin flat plate. And some predicted results were compared with the experimental data. The aspect ration of test model is d/t=25 (d; width, t; thickness). From the measurement of the flow field it was found that in the case of small inclined (.alpha.=10.deg., 20.deg.) relatively, the separated boundary layer at sharp leading edge developed smoothly downstream. With increasing the angle of attack of the plate, stagnation region was appeared on the back side of the plate and separated boundary layer was extended downstream. These trends are a good agreement with the computational results. It was found by analysis of response spectra of cantilever plate that the influences of vortex shedding frequency were important at the large of attack (.alpha.=30.deg.), and two peak values appear in entire test model at 24Hz, 150Hz.

• Nuclear Engineering and Technology
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• v.50 no.8
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• pp.1330-1338
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• 2018

High-density UMo/Zr monolithic nuclear fuel plates have a promising application prospect in high flux research and test reactors. The solid state welding method called co-rolling is used for their fabrication. Hot co-rolling simulations for the composite blanks of UMo/Zr monolithic nuclear fuel plates are performed. The effects of coupon sizes and mechanical property parameters on the contact pressures between the to-be-bonded surfaces are investigated and analyzed. The numerical simulation results indicate that 1) the maximum contact pressures between the fuel coupon and the Zircaloy cover exist near the central line along the plate length direction; as a whole the contact pressures decrease toward the edges in the plate width direction; and lower contact pressures appear at a large zone near the coupon corner, where de-bonding is easy to take place in the in-pile irradiation environments; 2) the maximum contact pressures between the fuel coupon and the Zircaloy parts increase with the initial coupon thickness; after reaching a certain thickness value, the contact pressures hardly change, which was mainly induced by the complex deformation mechanism and special mechanical constitutive relation of fuel coupon; 3) softer fuel coupon will result in lower contact pressures and form interfaces being more out-of-flatness.

• Journal of Welding and Joining
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• v.32 no.6
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• pp.75-81
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• 2014

Usage of heavy metal element (Pb, Hg and Cd etc.) in electronic devices have been restricted due to the environmental banning of the European Union, such as WEEE and RoHS. Therefore, it is needed to develop the Pb-free solder plated ribbon in photovoltaic (PV) module. This study described that degradation characteristics of PV module under damp heat (DH, $85^{\circ}C$ and 85% R.H.) condition test for 1,000 h. Solar cell ribbons were utilized to hot dipping plate with Pb-free solder alloys. Two types of Pb-free solder plated ribbons, Sn-3.0Ag-0.5Cu (SAC305) and Sn-48Bi-2Ag, and an electroless Sn-40Pb solder hot dipping plated ribbon as a reference sample were prepared to evaluate degradation characteristics. To detect the degradation of PV module with the eutectic and Pb-free solder plated ribbons, I-V curve, electro-luminescence (EL) and cross-sectional SEM analysis were carried out. DH test results show that the reason of maximum power (Pm) drop was mainly due to the decrease fill factor (FF). It was attributed to the crack or oxidation of interface between the cell and the ribbon. Among PV modules with the eutectic and Pb-free solder plated ribbon, the PV module with SAC305 ribbon relatively showed higher stability after DH test than the case of PV module with Sn-40Pb and Sn-48Bi-2Ag solder plated ribbons.

• The Korean Journal of Pain
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• v.13 no.2
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• pp.149-155
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• 2000

Background: Pulsed radiofrequency (RF) lesioning is a painless procedure and causes no neurodestruction and neuritis-like reaction are common following conventional RF lesioning. There is little data about the effect of pulsed RF especially with regard to its suitability for the treatment of acute pain. The possibility of a placebo effect cannot be ruled out because a double-blind study was not performed in previous studies. There is also no neuropathologic study about pulsed RF. Methods: The rats were anesthetized with sodium pentobarbital (40 mg/kg, i.p.; supplemented as necessary). The common sciatic nerve was exposed by blunt dissection through biceps femoris. Pulsed RF was administered to the common sciatic nerve using a 30 ms/s pulse with for 120 seconds. The temperature reached was no more than $42^{\circ}C$. Analgesia was determined using hot-plate assay shortly and, 3 days and 1 week before, and 2 weeks after operation. Lesions were examined with LM (light microscope) and EM (electron microscope) 2 weeks later. Results: There were no differences in response latencies between the control and experimental group. There were many vacuoles with hyaline bodies in the Schwann cell cytoplasm rather than axon in LM and larger electron dense bodies. No changes were found in the axon or unmyelinated fibers. Only small changes were found in the sheaths of myelinated fibers and Schwann cells. Conclusions: We therefore do think that any analgesic effect of pulsed RF is not a result of block of neural conduction. But rather than it can be attributed to others factors. It was also ineffective as a treatment for acute pain such as that caused by the hot-plate test.

• Journal of the Korean Society for Nondestructive Testing
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• v.26 no.4
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• pp.211-219
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• 2006

The UET(ultrasound excited thermography) for the ,eat-time diagnostics of the object employs an infrared camera to image defects of the surface and subsurface which are locally heated using high-frequency putted ultrasonic excitation. The dissipation of high-power ultrasonic energy around the feces of the defects causes an increase In temperature. The defect's image appears as a hot spot (bright IR source) within a dark background field. The UET for nondestructive diagnostic and evaluation is based on the image analysis of the hot spot as a local response to ultrasonic excited heat deposition. In this paper the applicability of VET for fast imaging of defect is described. The ultrasonic energy is injected into the sample through a transducer in the vertical and horizontal directions respectively. The voltage applied to the transducer is measured by digital oscilloscope, and the waveform are compared. Measurements were performed on four kinds of materials: SUS fatigue crack specimen(thickness 14mm), PCB plate(1.8 mm), CFRP plate(3 mm) and Inconel 600 plate (1 mm). A high power ultrasonic energy with pulse durations of 250ms Is injected into the samples in the horizontal and vertical directions respectively The obtained experimental result reveals that the dissipation loss of the ultrasonic energy In the vertical injection is less than that in the horizontal direction. In the cafe or PCB, CFRP, the size of hot spot in the vortical injection if larger than that in horizontal direction. Duration time of the hot spot in the vertical direction is three times as long as that in the horizontal direction. In the case of Inconel 600 plate and SUS sample, the hot spot in the horizontal injection was detected faster than that in the vertical direction