• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.28 no.11
• /
• pp.1348-1358
• /
• 2004

The filling pattern and an adaptive grid refinement based on the finite element method and Eulerian mesh advancement approach have been developed to analyze incompressible transient viscous flow with free surfaces. The governing equation fur flow analysis is Navier-Stokes equation including inertia and gravity effects. The mixed FE formulation and predictor-corrector method are used effectively for unsteady numerical simulation. The flow front surface and the volume inflow rate are calculated using the filling pattern technique to select an adequate pattern among seven filling patterns at each tetrahedral control volume. By adaptive grid refinement, the new flow field that renders better prediction in flow surface shape is generated and the velocity field at the flow front part is calculated more exactly. In this domain the elements in the surface region are made finer than those in the remaining regions for more efficient computation. The collapse of a water dam and the filling of a fluidity spiral have been analyzed. The numerical results have been in good agreement with the experimental results and the efficiency of the adaptive grid refinement and filling pattern techniques have been verified.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2008.03a
• /
• pp.39-44
• /
• 2008

In this paper, heat transfer coefficients were measured in a channel with one side dimpled surface. The sphere type dimples were fabricated and the diameter and depth of dimple was 16mm and 4mm, respectively. Two channel heights of about 0.6 and 1.2 time of the dimple diameter, two dimple configuration were tested. The Reynolds numbers based on the channel hydraulic diameter was varied from 30000 to 50000. The improved hue detection based transient liquid crystal technique was used in the heat transfer measurement. Heat transfer measurement results showed that high heat transfer was induced downstream of dimples due to flow reattachment. Due to the flow recirculation on the upstream side in the dimple, the heat transfer coefficient was very low. As the Reynolds increased, the overall heat transfer coefficients also increased. With same dimple arrangement, the heat transfer coefficients and the thermal performance factor were higher for the lower channel height. As the distance between dimples became smaller, the overall heat transfer coefficient and the thermal performance factor were increased.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.21 no.2
• /
• pp.152-162
• /
• 2001

Laser-generated ultrasonic technique which is one of the reliable nondestructive evaluation techniques has been applied to evaluate the integrity of structures by analyzing the characteristics of signal obtained from surface crack. Therefore, the signal analysis of the laser-generated ultrasonics is absolutely necessary for the accurate and quantitative estimation of the surface defects. In this study, one-sided measurement by laser-generated ultrasonic has been applied to evaluate the depth of the surface-breaking crack in the materials. However, since the ultrasonic waveform excited by pulse laser is very difficult to distinguish the defect signals, it is necessary to consider the signal analyses of the transient waveform. Wavelet Transform(WT) is a powerful tool for processing transient signals with temporally varying spectra that helps to resolve high and low frequency transient components effectively. In this paper, the analyses of the surface-breaking crack of the ultrasonic signal excited by pulse laser are presented by employing the WT analyses.

• Journal of Ocean Engineering and Technology
• /
• v.20 no.2 s.69
• /
• pp.59-65
• /
• 2006

Steel, as a reinforcing mechanism in concrete, provides the tensile strength that is lacking in concrete, alone, and the high alkaline environment (pH 12.5) in concrete offers satisfactory protection against most corrosion of the steel. However, the corrosion of reinforcing steel in concrete can occur by chloride attack or carbonation, and it can cause a loss of integrity a section and concrete failure through cracking and spalling. In this study, a transient electro magnetic method (TEM) of a nondestructive technique is adapted to study the measuring method of steel corrosion in mortar. The sensor was made of an enameled wire, with a diameter of 0.25mm and anacril. He sensor configuration used was a coincident loop type. The secondary electro motive force (2nd EMF) was measured with SIROTEMIII, which equipped the accelerator. The accelerator allowsthe transmitter to turn off approximately $10\sim15$ times faster than normal. The high-resolution time series, used for very shallow or a high resistivity investigation was selected. After steels were corroded by the salt spray, during 4, 8, 15 and 25 days, they were embedded in mortar. The content results acquired in this study are as follows. The variation of the secondary electro motive force (2nd EMF) was shown by the change of steel surface with different corrosion time steel. It was confirmed that measurement of steel corrosion in mortar by a transient electro-magnetic method (TEM) can be possible.

• 제어로봇시스템학회:학술대회논문집
• /
• 2004.08a
• /
• pp.1371-1374
• /
• 2004

The control system design of 2-DOF for SISO process by root locus technique is not complicated and efficiently. It can design the control system to have the transient and steady state responses, and do not adjust the gain of process controller later. However, due to control system design for MIMO process, by root locus technique, there is not exact method. This paper is presents the control system design method for Quadruple-Tank Process, by using root locus technique for the structure of 2-DOF control system. The design procedures are first decentralized then using the relative gain array, and finally 2-DOF controller design is applied.

• Proceedings of the KIEE Conference
• /
• 1992.07a
• /
• pp.118-121
• /
• 1992

This paper presents an optimal Fuzzy Control Technique to control the load frequency control of multiarea power system with a given stepwise load disturbance. The related simulation results show that the optimized fuzzy control technique are more effective than the conventional control technique (TBC, Optimal Control and etc) for reduction of load frequency deviation in transient and stedy-state, and for minimization of settling time.

• The Journal of Korean Medicine
• /
• v.24 no.2
• /
• pp.66-80
• /
• 2003

Objectives : Recently, herbal acupuncture has been developed in the Korea since the earlier 1960' applied to various diseases including the cerebrovascular accident. The main characteristics of herbal acupuncture are a combination the merit of acupuncture and herbal medicine. It was not well known the therapeutic effect and the mechanism of herbal acupuncture on transient forebrain ischemic injury, although it has been used frequently in clinics. Ramulus Uncariae Cum Uncis (釣鉤藤) has been claimed to possess sedative, anti-spasmodic actions, and treat childhood epilepsy in oriental medical preparation. Also, it has been stated that Ramulus Uncariae Cum Uncis was antioxidatvie effect and neuroprotection against glutamateinduced neuronal death. Methods : In this study, effects of Ramulus Uncariae Cum Uncis' herbal acupuncture on the $GV_{20}{\;}or{\;}LR_3$, named Baek-hue or Tae-chung, on neuroprotection after the transient forebrain ischemia were investigated in Sprague-Dawely rats. Expressions of cFos, FosB and BDNF protein in the hippocampus and cortex were observed at 2 hrs and 48 hrs after transient forebrain ischemia by immunohistochemistry and ELISA technique. Results : Expression of cFos protein was increased slightly in the hippocampus and cortex at 2 hrs after transient forebrain ischemia, but FosB protein was increased highly comparing to cFos protein. However, pretreatment with Ramulus Uncariae Cum Uncis' herbal acupuncture on $GV_{20}{\;}or{\;}LR_3$ significantly increased expression of cFos protein and significantly decreased expression of FosB protein compared to control group, respectively. These features were observed in the motor cortex and retrosplenial granular cortex as well as the hippocampus. Especially, cFos expression was more increased at the herbal acupuncture on $GV_{20}{\;}than{\;}LR_3$, but FosB expression was more decreased in $LR_3$ group than $GV_{20}$ group. Also, pretreatment with Ramulus Uncariae Cum Uncis' herbal acupuncture on $GV_{20}{\;}or{\;}LR_3$ significantly increased the expression of BDNF protein in the hippocampus ($254.88{\pm}12{\;}pg/ml{\;}in{\;}GV_{20}$ group, $245.93{\pm}44.4{\;}pg/ml{\;}in{\;}LR_3$ group) and the cortex ($85.81{\pm}3.45{\;}pg/ml{\;}in{\;}GV_{20}$ group, $111.51{\pm}15.79{\;}pg/ml{\;}in{\;}LR_3$, group) compared to the hippocampus ($134.07{\pm}2.96{\;}pg/ml$) and the cortex ($61.16{\pm}4.11{\;}pg/ml$) in control group at 48 hrs after transient forebrain ischemia. Conclusion : These results suggest that pretreatment with Ramulus Uncariae Cum Uncis' herbal acupuncture on $GV_{20}{\;}or{\;}LR_3$ has neuroprotective effect on transient forebrain ischemia and the herbal acupunture on $GV_{20}{\;}or{\;}LR_3$ may be related to antioxidative effect and calcium channel block of Ramulus Uncariae Cum Uncis. Also, it could be mentioned there is specificity of acupoints treating ischemic injury through the difference between the herbal acupuncture of $GV_{20}{\;}and{\;}LR_3$.

• The Journal of Korean Medicine
• /
• v.24 no.2
• /
• pp.81-93
• /
• 2003

Objectives : Recently, the new therapeutic tool, that is herbal acupuncture, has been developed and applied to various diseases including the cerebrovascular accident. The main characteristics of herbal acupuncture are a combination of acupuncture and herbal medicine. It was not well known the therapeutic effect and the mechanism of herbal acupuncture on transient forebrain ischemic injury, although it has been used frequently in clinics. The objective was to determine the effect of folium artemisiae argyi (艾葉) herbal acupuncture on the trasient forebrain ischemic injured rat. Methods : In this study, the effects of folium artemisiae argyi (艾葉) herbal acupuncture on the $LR_3$ named Taechung, on neuroprotection after the transient forebrain ischemia were investigated in Sprague-Dawely rats. Expressions of cFos, FosB and BDNF protein in the hippocampus and cortex were observed at 2 hrs and 48 hrs after transient forebrain ischemia by immunohistochemistry and ELISA technique. Results : Expression of cFos protein was increased slightly in the hippocampus and cortex at 2 hrs after transient forebrain ischemia, but FosB protein was increased highly comparing to cFos protein. However, pretreatment with folium artemisiae argyi' herbal acupuncture on $LR_3$ significantly increased expression of cFos protein and significantly decreased expression of FosB protein compared to control group. These features were observed in the retrosplenial granular cortex as well as the hippocampus. Also, pretreatment with folium artemisiae argyi' herbal acupuncture on $LR_3$ significantly increased the expression of BDNF protein in the hippocampus ($263.26{\pm}44.56{\;}pg/ml$ extracted by water, $275.35{\pm}51.47{\;}pg/ml$ extracted by moxa tar)and the cortex ($102.33{\pm}13.65{\;}pg/ml$ extracted by water, $109.54{\pm}9.37{\;}pg/ml$ extracted by moxa tar) compared to the hippocampus ($134.07{\pm}2.96{\;}pg/ml$) and the cortex ($61.16{\pm}4.11{\;}pg/ml$) in control group at 48 hrs after transient forebrain ischemia. Conclusions : These results suggest that pretreatment with folium artemisiae argyi' herbal acupuncture on $LR_3$ has neuroprotective effect on transient forebrain ischemia and the herbal acupunture on $LR_3$ may be related to antioxidative function of folium artemisiae argyi.

• Korean Journal of Acupuncture
• /
• v.20 no.3
• /
• pp.61-80
• /
• 2003

Objectives : Acupuncture and herbal medicine have been used to prevent and treat the cerebrovascular accident, such as a stroke, and many studies of acupuncture and moxibustion concerning to the stroke have been undertaken in the human and various animals. Recently, the new therapeutic tool, that is herbal acupuncture, has been developed since the 1950' and applied to various diseases including the cerebrovascular accident. The main characteristics of herbal acupuncture are a combination of acupuncture and herbal medicine. It was not well known the therapeutic effect and the mechanism of herbal acupuncture on transient forebrain ischemic injury, although it has been used frequently in clinics. Methods : In this study, effects of folium Artemisiae Argyi and moxa tar' herbal acupuncture on the $GV_{20}$, named Baek-Hue, on neuroprotection after the transient forebrain ischemia were investigated in Sprague-Dawely rats. Expressions of cFos, FosB and BDNF protein in the hippocampus and cortex were observed at 2 hrs and 48 hrs after transient forebrain ischemia by immunohis- tochemistry and ELISA technique. Results : Expression of cFos protein was increased slightly in the hippocampus and cortex at 2 hrs after transient forebrain ischemia, but FosB protein was increased highly comparing to cFos protein. However, pretreatment with folium Artemisiae Argyi or moxa tar' herbal acupuncture on $GV_{20}$ significantly increased expression of cFos protein and significantly decreased expression of FosB protein compared to control group, respectively. These features were observed in the motor cortex and retrosplenial granular cortex as well as the hippocampus. Also, pretreatment with folium Artemisiae Argyi and moxa tar' herbal acupuncture on$GV_{20}$ significantly increased the expression of BDNF protein in the hippocampus and the cortex compared to control group at 48 hrs after transient forebrain ischemia, respectively. Conclusions : These results suggest that pretreatment with folium Artemisiae Argyi or moxa tar' herbal acupuncture on $GV_{20}$ has neuroprotective effect on transient forebrain ischemia and theherbal acupuncture on $GV_{20}$ may be related to antioxidative function.

• Korean Journal of Acupuncture
• /
• v.22 no.3
• /
• pp.63-81
• /
• 2005

Herbal acupuncture has been used to prevent and treat the cerebrovascular accident, such as a stroke, and many studies of acupuncture and moxibustion concerning to the stroke have been undertaken in the human and various animals. The main characteristics of herbal acupuncture are a combination of acupuncture and herbal medicine. It was not well known the therapeutic effect and the mechanism of herbal acupuncture on transient forebrain ischemic injury, although it has been used frequently in clinics. In this study, neuroprotective effects of folium artemisiae argyi (艾葉)' herbal acupuncture on the $LR_3$ (Taechung) on the transient forebrain ischemia were investigated in Sprague-Dawely rats. Expressions of cFos, FosB and BDNF protein in the hippocampus and cortex were observed at 2 hrs and 48 hrs after transient forebrain ischemia by immunohistochemistry and ELISA technique. Expression of cFos protein was increased slightly in the hippocampus and cortex at 2 hrs after transient forebrain ischemia, but FosB protein was increased highly comparing to cFos protein. However, pretreatment with folium artemisiae argyi' herbal acupuncture on $LR_3$ significantly increased expression of cFos protein and significantly decreased expression of FosB protein compared to control group. These features were observed in the motor cortex and retrosplenial granular cortex as well as the hippocampus. Also, pretreatment with folium artemisiae argyi' herbal acupuncture on $LR_3$ significantly increased the expression of BDNF protein in the hippocampus ($263.26{\pm}44.56pg/ml$ extracted by water, $275.35{\pm}51.47pg/ml$ extracted by moxa tar)and the cortex ($102.33{\pm}13.65pg/ml$ extracted by water, $109.54{\pm}9.37pg/ml$ extracted by moxa tar) compared to the hippocampus $(134.07{\pm}2.96pg/ml)$ and the cortex $(61.16{\pm}4.11pg/ml)$ in control group at 48 hrs after transient forebrain ischemia. These results suggest that pretreatment with folium artemisiae argyi'herbal acupuncture on $LR_3$ has neuroprotective effect on transient forebrain ischemia and the herbal acupunture on $LR_3$ may be related to antioxidative function of folium artemisiae argyi.