• Annals of Clinical Neurophysiology
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• v.16 no.1
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• pp.21-26
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• 2014

Background: Electrophysiological study has been known as a useful method to evaluate the therapeutic effect of operation in idiopathic carpal tunnel syndrome (CTS). The purpose of this study was to evaluate the clinical and electrophysiological changes after carpal tunnel release (CTR) compared to the preoperative results. Methods: We analyzed the changes of nerve conduction study (NCS) before and after minimal open carpal tunnel release in 18 patients (25 hands) with CTS. Follow-up study was performed over 6 months after operation. Results: Clinical improvement was seen in all cases after CTR. In contrast, electrophysiological improvement was various depending on the parameters; the mean median sensory latency and nerve conduction velocity (NCV) improved significantly (p = 0.001). The mean median motor latency also improved, but NCV and compound muscle action potential (CMAP) amplitude did not change. The extent of improvement was evident in moderate CTS, but not in severe CTS. Conclusions: In this preliminary study, all subjects who underwent CTR achieved a clinical relief along with a significant improvement of electrophysiological parameters such as median sensory latency, sensory NCV and median distal motor latency. After CTR, a number of cases with mild to moderate CTS showed a prominent improvement of clinical and electrophysiological parameters, while fewer improvements were seen in severe CTS, although it did not reach the statistical significance.

• Journal of Korean Physical Therapy Science
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• v.3 no.1
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• pp.929-941
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• 1996

This study was conducted to determine the association between weighted needle pinprick sensory threshold(PPT) and sensory nerve conduction studies. The subjects were 53 healthy controls, 31 diabetic patients without peripheral neuropathic symptoms(DM) and 36 diabetic patients with peripheral neuropathic symptoms(DN). PPT was measured on the index and little fingers, bilaterally, as well as under the lateral malleolus, bilaterally. In electrophysiologic assessment the left and right median, ulnar and sural nerves were studied. Mean PPT in DN, DM and controls was high in turn on each sites tested. Age controlled PPT was significantly different among three groups on right little finger(p<0.05) and left malleolus(p<0.05), but on other sites, not statistically significantly different between DN and DM. The results were as follows: Sensory nerve conduction velocity and amplitude on each nerve tested were statistically significantly different among three groups(p<0.05). Correlation of PPT with sensory nerve conduction velocity and amplitude were statistically significant on each site and ranged from -0.4203(left malleolus) to -0.5649(right index finger) and from -0.3897(left index finger) to -0.6200(right index finger), respectively. When electrophysiological study is not feasible, measurement of PPT may be helpful for the assessment of peripheral sensory neurological function.

• Journal of Preventive Medicine and Public Health
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• v.28 no.4 s.51
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• pp.899-910
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• 1995

This study was conducted to determine the correlation between weighted needle pinprick sensory threshold(PPT) and sensory nerve conduction tests. The subjects were 53 healthy controls, 31 diabetic patients without peripheral neuropathic symptoms(DM) and 36 diabetic patients with peripheral neuropathic symptoms(DN). PPT was measured on the index and little fingers, bilaterally, as well as under the lateral malleolus, bilaterally. In electrophysiologic assessment the left and right median, ulnar and sural nerves were studied. Each mean PPTs was high in order of controls, DM and DN. Age adjusted PPT was significantly different among three groups on right little finger(p<0.05) and left malleolus(p<0.05), but not significantly different between DN and DM on other sites. Each sensory nerve conduction velocity and amplitude was statistically significantly different among three groups(p<0.05). Correlations of PPT with sensory nerve conduction velocity and amplitude were statistically significant on each site and ranged from -0.4203(left malleolus) to -0.5649(right index finger) and from -0.3897(left index finger) to -0.6200(right index finger), respectively. When electrophysiological study is not feasible, measurement of PPT may be helpful for the assessment of peripheral sensory neurological function.

• Archives of Plastic Surgery
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• v.34 no.3
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• pp.279-284
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• 2007

Purpose: The vein graft was considered as a useful conduit for nerve defect. But the problem is that it might be collapsed in long vein graft state. A new experimental model using vein graft filled with hyaluronic acid was considered. Methods: Thirty rats were used for the experimental animal. In group I, one side of the femoral nerve was exposed and a segment was removed about 15mm. The neural gap was connected with nerve graft. In group II, the nerve gap was connected with vein graft only. In group III, the nerve gap was connected with vein graft filled with hyaluronic acid. A walking track analysis was made periodically for 2 months and NCV(nerve conduction velocity) was executed at the end of the experiment. And morphologic studies were also done for all groups Results: In a walking track analysis, the toe-spread was widen and the foot-length was lengthened. The recovery of the toe-spread and foot length was checked 2 weeks interval, periodically for two months. The SFI (sciatic function index) was $-52.5{\pm}8.2$ in group I, $-68.1{\pm}4$ in group II, $-55.3{\pm}7.9$ in group III. In electrophysiological study, NCV(nerve conduction velocity) was $26.71{\pm}3.11m/s$ in group I, $17.94{\pm}4.35m/s$ in group II, $25.69{\pm}2.81m/s$ in group III. The functional recovery in group I and III was superior to that the group II statistically(p < 0.05) Under electromicroscopic study, the number of the myelinated axons were $1419.1{\pm}240$ in group I, $921.7{\pm}176.8$ in group II, $1322.2{\pm}318$ in group III. The number of the myelinated axons were much more in group I and III than group II statistically (p<0.05). Conclusion: This study suggested that the vein graft filled with hyaluronic acid is more effective than vein graft only for the conduit of the nerve gap. It was thought that the technique could be used in clinical cases with nerve defects as an alternative method to classical nerve grafts.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.7
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• pp.567-578
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• 2015

Single droplet-wall collision heat transfer characteristics on a heated plate above Leidenfrost temperature were experimentally investigated considering the effects of impact velocity. The collision characteristics of the droplet impinged on the heated wall and the changes in temperature distribution were simultaneously measured using synchronized high-speed video and infrared cameras. The surface heat flux distribution was obtained by solving the three-dimensional transient heat conduction equation for the heated substrate using the measured surface temperature data as the boundary condition for the collision surface. As the normal impact velocity increased, heat transfer effectiveness increased because of an increase in the maximum spreading diameter and a decrease in the vapor film thickness between the droplet and heated wall. For We < 30, droplets stably rebounded from a heated wall without breakup. However, the droplets broke up into small droplets for We > 30. The tendency of the heat transfer to increase with increasing impact velocity was degraded by the transition from the rebounding region to the breakup region; this was resulted from the reduction in the effective heat transfer area enlargement due to the breakup phenomenon.

• Journal of the Korea Concrete Institute
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• v.15 no.2
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• pp.305-313
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• 2003

The setting and hardening of concrete is accompanied with nonlinear temperature distribution caused by development of hydration heat of cement. Especially at early ages, this nonlinear distribution has a large influence on the crack evolution. As a result, in order to predict the exact temperature history in concrete structures it is required to examine thermal properties of concrete. In this study, the coefficient of air convection, which presents thermal transfer between surface of concrete and air, was experimentally investigated with variables such as velocity of wind and types of form. From experimental results, the coefficient of air convection was calculated using equations of thermal equilibrium. Finally, the prediction model for equivalent coefficient of air convection including effects of velocity of wind and types of form was theoretically proposed. The coefficient of air convection in the proposed model increases with velocity of wind, and its dependance on wind velocity is varied with types of form. This tendency is due to a combined heat transfer system of conduction through form and convection to air. From comparison with experimental results, the coefficient of air convection by this model was well agreed with those by experimental results.

• Journal of the Korea Concrete Institute
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• v.17 no.4 s.88
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• pp.551-558
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• 2005

The setting and hardening of concrete is accompanied with nonlinear temperature distribution caused by development of hydration heat of cement. Especially at early ages, this nonlinear distribution has a large influence on the crack evolution. As a result, in order to predict the exact temperature history in concrete structures it is required to examine thermal properties of concrete. In this study, the convection heat transfer coefficient which presents thermal transfer between surface of concrete and air, was experimentally investigated with variables such as velocity of wind, curing condition and ambient temperature. At initial stage, the convection heat transfer coefficient is overestimated by the evaporation quantity. So it is essential to modify the thermal equilibrium considered with the boiling effect. From experimental results, the convection heat transfer coefficient was calculated using equations of thermal equilibrium. Finally, the prediction model for equivalent convection heat transfer coefficient including effects of velocity of wind, curing condition, ambient temperature and boiling effects was theoretically proposed. The convection heat transfer coefficient in the proposed model increases with velocity of wind, and its dependance on wind velocity is varied with curing condition. This tendency is due to a combined heat transfer system of conduction through form and convection to air. From comparison with experimental results, the convection heat transfer coefficient by this model was well agreed with those by experimental results.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.2
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• pp.119-124
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• 2015

Numerical study on the new design of the liquid mass flow meter in infinitesimal flow rate for semiconductor production is performed. The heater and thermistor are wired on the circular tube about 0.3mm inner diameter with designed gap between them. After the time interval from the single pulse heating the thermistor reaches its peak temperature and this time interval is almost inversely proportional to the liquid mass flow rate. The axial conduction in tube wall and convection through the flow is combined. As a result, the peak temperature moving velocity is much smaller than flow mean velocity and there is no linear relationship between them. In this study, the effects of design parameters such as the tube inner/outer diameter, wired heater width, and the gap between heater and thermistor are investigated and the trends of optimization in these parameters are discussed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.5
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• pp.668-676
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• 2003

The effect of nozzle height on heat transfer of a hot steel plate cooled by an impinging liquid jet is not well understood. Previous studies have been based on the dimensionless parameter z/d. To test the validity of this dimensionless parameter and to investigate gravitational effects on the jet, stagnation velocity of an impinging liquid jet were measured and the cooling experiments of a hot steel plate were conducted for z/d from 6.7 to 75, and an inverse heat conduction method is applied for the quantitative comparison. Also, the critical instability point of a liquid jet was examined over a range of flow rates. The experimental velocity data for the liquid jet were well correlated with the dimensionless number 1/F $r_{z}$$^2$based on distance. It was thought that the z/d parameter was not valid for heat transfer to an impinging liquid jet under gravitational forces. In the cooling experiments, heat transfer was independent of z when 1/F $r_{z}$$^2$< 0.187(z/d = 6.7). However, it was found that the heat transfer quantity for 1/F $r_{z}$$^2$=0.523(z/d = 70) is larger 11% than that in the region for 1/F $r_{z}$$^2$=0.187. The discrepancy between these results and previous research is likely due to the instability of liquid jet.uid jet.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.1
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• pp.37-46
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• 2017

Thermal Marangoni flow has been observed inside droplets on heated surfaces, finally resulting in a coffee stain effect. This study aims to visualize and control the thermal Marangoni flow by employing periodic vertical vibration. The variations in the contact angle and internal volume of the droplet as it evaporates is observed by using a combination of continuous light and a still camera. With regard to the internal velocity, the particle image velocimetry system is applied to visualize the internal thermal Marangoni flow. In order to estimate the internal temperature gradient and surface tension on the surface of a droplet, the theoretical model based on the conduction and convection theory of heat transfer is applied. Thus, the internal velocity increases with an increase in plate temperature. The flow directions of the Marangoni and gravitational flows are opposite, and hence, it may be possible to control the coffee stain effect.