• Proceedings of the KSME Conference
• /
• 2003.04a
• /
• pp.431-437
• /
• 2003

KAERI has contrived 14 kinds of spacer grid shapes of its own since 1997 and applied for Korean and US patents. To date. KAERI has obtained US and Korean patents for 6 kinds of spacer grid shapes among them. Tn this study. performance test on two spacer grid shapes that are assumed to be the most effective candidates for the spacer grid of the next generation nuclear fuel in Korea was carried Qui through the mechanical/structural test and analysis. The test result has shown thai the performances of the candidates are better or not worse than that of the current spacer grid.

• Tribology and Lubricants
• /
• v.15 no.1
• /
• pp.83-89
• /
• 1999

The fretting wear behaviour of Zircaloy-4 tube used as the fuel rod cladding in PWR nuclear power plants has been investigated at the different test environment, in light water and in air as a function of slip amplitude, normal load, test duration and frequency. Zircaloy-4 tubes were used for both of oscillating and stationary specimens. A fretting wear tester was designed to be suitable for this fretting test. The wear volume and specific wear rate of Zircaloy-4 tube in water was greater than those in air under various slip amplitude. Delaminates and surface cracks were observed at low slip amplitude and high load of fretting test in water, but the traces of adhesion and plowing were observed at and above 200 Um. The water accelerates the wear of Zircaloy-4 tube at lower slip amplitude in fretting.

• YAKHAK HOEJI
• /
• v.29 no.4
• /
• pp.206-215
• /
• 1985

1) Puerariae Radix butanol ext. (100, 200, 400mg/kg, p.o. single treatment) alone partly showed blood pressure decreasing effect in SHRs and increasing effect of urinary volume in normal rats. 2) Cadmium nitrate (10mg/kg, s.c. single treatment) induced toxicity such as body weight decreasing effect, antidiuretic effect and muscle relaxant effect such as pull-up test, traction test and rota rod test in rats. However, Puerariae Radix butanol ext. (100, 200, 400mg/kg, p.o. single treatment) showed antidotal effects on the above and also in acute toxicity test when coadministered with both of them. 3) Cadmium nitrate (1mg/kg, s.c. 7 days consecutive treatment) did not showed toxicity in body weight change, blood pressure, change, serum biochemical parameters in rats. Puerariae Radix butanol ext. (100, 200, 400mg/kg, p.o. 7 days consecutive treatment) did not also showed any antidotal effects when coadministered with both of them for 7 days.

• Annals of Clinical Neurophysiology
• /
• v.16 no.2
• /
• pp.62-69
• /
• 2014

Background: Neuromodulation therapy has been used to an adjunctive treatment promoting motor recovery in stroke patients. The objective of the study was to determine the effect of repetitive transcranial magnetic stimulation (rTMS) on neurobehavioral recovery and evoked potentials in rats with middle cerebral artery occlusion. Methods: Seventy Sprague-Daley rats were induced permanent middle cerebral artery occlusion (MCAO) stroke model and successful stroke rats (n=56) assigned to the rTMS (n=28) and sham (n=28) group. The 10 Hz, high frequency rTMS gave on ipsilesional forepaw motor cortex during 2 weeks in rTMS group. The somatosensory evoked potential (SSEP) and motor evoked potential (MEP) were used to evaluate the electrophysiological changes. Behavioral function of the stroke rat was evaluated by the Rota rod and Garcia test. Results: Forty rats ($N_{rTMS}=20;\;N_{sham}=20$) completed all experimental course. The rTMS group showed better performance than sham group in Rota rod test and Garcia test at day 11 (p<0.05) but not day 18 (p>0.05). The amplitude of MEP and SSEP in rTMS group was larger than sham group at day 18 (p<0.05). Conclusions: These data confirm that the high frequency rTMS on ipsilesional cerebral motor cortex can help the early recovery of motor performance in permanent middle cerebral artery stroke model and it may simultaneously associate with changes in neurophysiological activity in brain.

• Nuclear Engineering and Technology
• /
• v.45 no.7
• /
• pp.941-950
• /
• 2013

The Korean Nuclear-Hydrogen Technology Development (NHTD) Plan will be performing irradiation testing of coated particle fuel at HANARO to support the development of VHTR in Korea. This testing will be carried out to demonstrate and qualify TRISO-coated particle fuel for use in VHTR. The testing will be irradiated in an inert gas atmosphere without on-line temperature monitoring and control combined with on-line fission product monitoring of the sweep gas. The irradiation device contains two test rods, one has nine fuel compacts and the other five compacts and eight graphite specimens. Each compact contains about 260 TRISO-coated particles. The irradiation device is being loaded and irradiated into the OR5 hole of the in HANARO core from August 2013. The device will be operated for about 150 effective full-power days at a peak temperature of about $1030^{\circ}C$ in BOC (Beginning of Cycle) during irradiation testing. After a peak burn-up of about 4 atomic percentage and a peak fast neutron fluence of about $1.7{\times}10^{21}\;n/cm^2$, PIE (Post-Irradiation Examination) of the irradiated coated particle fuel will be performed at IMEF (Irradiated Material Examination Facility). This paper reviews the design of test rod and irradiation device for coated particle fuel, and discusses the technical results for irradiation testing at HANARO.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.28 no.2C
• /
• pp.95-103
• /
• 2008

Seismic piezocone penetration tests (SCPTu) can be used to obtain dynamic properties of soils as well as cone resistance and penetration pore pressure. However, the SCPTu system can be hardly utilized in marine soils because it is difficult to install the source apparatus which generates the shear wave in offshore site. The authors developed an inhole type piezocone penetration test (CPTu) equipment which both source and receiver composed of bender elements were installed inside the rod located behind the cone. Therefore, it can be applicable to even an offshore site without any additional source apparatus. The objective of this paper is to investigate the practical application of inhole type CPTu by performing laboratory model tests using kaolinite as soft clay. The shear wave velocities of kaolinite soil were measured with time, and the effects of soil disturbance due to the installation of source and receiver were also examined for various distance between source and receiver.

• Journal of Korean Society of Steel Construction
• /
• v.25 no.4
• /
• pp.431-440
• /
• 2013

In this study, a standard tensile welded-joint test was conducted to select a welding electrode suitable for recently developed HSA800 steel. Two welding electrodes were available at the time of this study; one was GMAW-based and the other FCAW-based. The tensile test specimens were fabricated by joining 60mm-thick HSA800 plates according to the AWS-prequalified groove welded joint details. Specimens which violate the standard root opening distance (ROD) were also included to see if poor construction tolerance could be accommodated. During fabrication, serious concerns about the welding efficiency of the GMAW-based product were raised by a certified welder. Both welding electrodes showed satisfactory and similar performance from welded joint strength perspective. But groove welded joints made by using the FCAW-based rod consistently showed more ductile and stable behavior. The AISC provisions for PJP joint strength were shown to be very conservative under direct tensile loading. Violating the AWS prequalified ROD by 100% apparently passed the strength criteria, but unusual crater-like fracture surface was observed.

• Journal of Korean Ophthalmic Optics Society
• /
• v.8 no.2
• /
• pp.13-18
• /
• 2003

We did the comparison research about three different methods of measuring horizontal phoria and vertical phoria which are Von Graefe test, Maddox Rod test and polarizing lens test. The inspection was don with the subjective method of refraction about normal 63 subjects aged from 20 to 28 years old. The analysis of date resulted in as follows : 1. Using Von Graefe Horizontal phoria Measurement, they were measured 5% for orthpharia, 51% for exophoria and 44% for esophoria. 2. Using Von Graefe vertical phoria Measurement, they were measured 68% for orthphoria, 20% for left hypophoria against the right and 12% for left hyperphoria against the right. 3. Using Maddox Rod Horizontal phoria Measurement, they were measured 7% for orthphoria, 49% for exophoria and 44% for esophoria. 4. Using Maddox Rod vertical phoria Measurement, they were measured 70% for orthphoria, 19% for left hypophoria against the right and 11% for left hyperphoria against the right. 5. Using Polarizing Horizontal phoria Measurement, they were measured 10% for orthphoria, 49% for exophoria and 41% for esophoria. 6. Using Polarizing vertical phoria Measurement, they were measured 92% for orthpharia, 5% for left hypophoria against the right and 3% for left hyperphoria against the right.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.23 no.4
• /
• pp.56-61
• /
• 2009

This paper presents the ground surface potential profiles and hazard voltages around the metallic structure connected to a small-sized model ground electrode. Because it is very difficult to draw valid conclusions concerning a general grounding problem from actual field data, scale model tests can be used to determine the touch and stop voltages and surface potential profiles around ground electrode. In this work, a hemispherical vessel with a diameter of 1,100[mm] was employed to simulate uniform soil. As a result, the ground surface potential around the ground electrode was significantly raised In particular the ground surface potential at the just upper point of ground rod was higher than other points. When the buried depth of ground rod is increased, the ground surface potential and step voltage were lowered but the touch voltage was elevated.

• Smart Structures and Systems
• /
• v.18 no.2
• /
• pp.197-216
• /
• 2016

The increased speed of a train causes increased loads that act on the track substructures. To ensure the safety of the track substructures, proper maintenance and repair are necessary based on an accurate characterization of strength and stiffness. The objective of this study is to develop and apply a cone penetrometer incorporated with the dynamic cone penetration method (CPD) for investigating track substructures. The CPD consists of an outer rod for dynamic penetration in the ballast layer and an inner rod with load cells for static penetration in the subgrade. Additionally, an energy-monitoring module composed of strain gauges and an accelerometer is connected to the head of the outer rod to measure the dynamic responses during the dynamic penetration. Moreover, eight strain gauges are installed in the load cells for static penetration to measure the cone tip resistance and the friction resistance during static penetration. To investigate the applicability of the developed CPD, laboratory and field tests are performed. The results of the CPD tests, i.e., profiles of the corrected dynamic cone penetration index (CDI), profiles of the cone tip and friction resistances, and the friction ratio are obtained at high resolution. Moreover, the maximum shear modulus of the subgrade is estimated using the relationships between the static penetration resistances and the maximum shear modulus obtained from the laboratory tests. This study suggests that the CPD test may be a useful method for the characterization of track substructures.