• International Journal of Air-Conditioning and Refrigeration
• /
• v.15 no.4
• /
• pp.147-155
• /
• 2007

Mobile air conditioning systems work under widely changing operating conditions. To understand the system behavior under such dynamic conditions, a test facility that can impose transient loads as well as conducting dynamic measurements is needed. To test mobile air conditioning systems including their dynamic performance under various drive cycle patterns without using full scale vehicles in a wind tunnel, a new test facility, called "dynamic simulator," is described. It can replicate real vehicle operating conditions by interacting with the system being tested based on the measured system performance and subsequently adjusting the air properties returning to the test system based on the results of a numerical cabin model. A new dynamic simulator has been designed, constructed, and verified for performing dynamic tests. It was successful in controlling the temperature and relative humidity of the air returning to the test unit within ${\pm}0.7^{\circ}C$ and ${\pm}4%$ of their respective intended values. The verification test under the New European Driving Cycle demonstrated that detailed transient behavior of the mobile air conditioning system could be measured by using this dynamic simulator.

• Journal of the Microelectronics and Packaging Society
• /
• v.12 no.4 s.37
• /
• pp.331-338
• /
• 2005

The rapid advances in high power light sources and arrays as encountered in incandescent lamps have induced dramatic increases in die heat flux and power consumption at all levels of high power LED packaging. The lifetime of such devices and device arrays is determined by their temperature and thermal transients controlled by the powering and cooling, because they are usually operated under rough environmental conditions. The reliability of packaged electronics strongly depends on the die attach quality, because any void or a small delamination may cause instant temperature increase in the die, leading sooner or later to failure in the operation. Die attach materials have a key role in the thermal management of high power LED packages by providing the low thermal resistance between the heat generating LED chips and the heat dissipating heat slug. In this paper, thermal transient characteristics of die attach in high power LED package have been studied based on the thermal transient analysis using the evaluation of the structure function of the heat flow path. With high power LED packages fabricated by die attach materials such as Ag paste, solder paste and Au/Sn eutectic bonding, we have demonstrated characteristics such as cross-section analysis, shear test and visual inspection after shear test of die attach and how to detect die attach failures and to measure thermal resistance values of die attach in high power LED package. From the structure function oi the thermal transient characteristics, we could know the result that die attach quality of Au/Sn eutectic bonding presented the thermal resistance of about 3.5K/W. It was much better than those of Ag paste and solder paste presented the thermal resistance of about 11.5${\~}$14.2K/W and 4.4${\~}$4.6K/W, respectively.

• The Korean Journal of Physiology and Pharmacology
• /
• v.26 no.1
• /
• pp.47-57
• /
• 2022

Stiripentol is an anti-epileptic drug for the treating of refractory status epilepticus. It has been reported that stiripentol can attenuate seizure severity and reduce seizure-induced neuronal damage in animal models of epilepsy. The objective of the present study was to investigate effects of post-treatment with stiripentol on cognitive deficit and neuronal damage in the cornu ammonis 1 (CA1) region of the hippocampus proper following transient ischemia in the forebrain of gerbils. To evaluate ischemia-induced cognitive impairments, passive avoidance test and 8-arm radial maze test were performed. It was found that post-treatment with stiripentol at 20 mg/kg, but not 10 or 15 mg/kg, reduced ischemia-induced memory impairment. Transient ischemia-induced neuronal death in the CA1 region was also significantly attenuated only by 20 mg/kg stiripentol treatment after transient ischemia. In addition, 20 mg/kg stiripentol treatment significantly decreased ischemia-induced astrocyte damage and immunoglobulin G leakage. In brief, stiripentol treatment after transient ischemia ameliorated transient ischemia-induced cognitive impairment in gerbils, showing that pyramidal neurons were protected and astrocyte damage and blood brain barrier leakage were significantly attenuated in the hippocampus. Results of this study suggest stiripentol can be developed as a candidate of therapeutic drug for ischemic stroke.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.10 no.4
• /
• pp.100-105
• /
• 2002

In order to investigate how the chassis frame stiffness including body structure affects vehicle handling characteristics, in this paper, objective test evaluations such as steady state circle maneuvering test and pulse input transient test are performed. The basic steer characteristics can be obtained from stability factor and 4 parameter method is used to evaluate vehicle handling characteristics between original vehicle and the other with reinforced chassis. The result shows that vehicle with reinforced chassis has advantages in handling characteristics.

• Journal of Yeungnam Medical Science
• /
• v.14 no.2
• /
• pp.474-482
• /
• 1997

There have been some case reports of the coexistence of extraadrenal pheochromocytoma and renal artery stenosis. Some reporters proposed that their coexistence may be associated through a common pathophysiological mechanism mediated by catecholamine secretion. Also some noted that trasient renal artery stenosis due to a spasm was induced by the catecholamines released from pheochromacytoma. We report a case of left paraaortic extraadrenal pheochromacytoma that had a transient oral captopril test positive result. After 5 days ${\alpha}$-antagonist reduced the vasospastic response of catecholamines. After surgical removal of the tumor, plasma catecholamines and urinary vanillyhnandelic acid concentrations as well as the blood pressure level, were restored to normal.

• International Journal of Highway Engineering
• /
• v.16 no.4
• /
• pp.87-95
• /
• 2014

PURPOSES: Evaluation of thermal conductivity and convection properties of asphalt mixture by using thermodynamics. METHODS: In this research, temperature prediction model based on thermodynamics is derived for asphalt mixture in transient state and it is verified with laboratory test results. RESULTS: The derived temperature prediction model shows good agreement with laboratory test results. CONCLUSIONS: It is concluded that the derived model based on thermodynamics and thermal properties in the literature are good enough to capture temperature variation in laboratory test. The approach based on thermodynamics can be applied to more complex temperature simulations.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2000.07a
• /
• pp.152-155
• /
• 2000

PWM inverter-fed traction motor is able to occur problems by additive transient surge stress and harmonic loss in contrast with motor driven by 60Hz sine wave alternating source. Therefore in this paper, test method and standard of existed already were investigate, "thermal + electric" complex degradation test that considered additive degradation occurred by inverter drive carried out in order to obtain insulation reliability of traction motor driven by inverter. It seems that this test method confers large value of application at reliability estimation which the subject of complete motor not windings sample from now on.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.8
• /
• pp.3167-3172
• /
• 2015

Background: Understanding the history of human papilloma virus (HPV) infection is important for interpretation of a positive HPV DNA screening test, future work-up and treatment. We investigated the transition of HPV DNA test results in Korean women, and analyzed the association of cytology result with transition type. Materials and Methods: We retrospectively reviewed annual HPV DNA test results for 5,274 subjects between January 2005 and December 2012. Each subject had a minimum of five annual tests over the eight-year period. Based on the pattern of results, the transition type for each subject was assigned to one of the following: negative, persistent, latent, transient, and unclassifiable. Associations of cytology results with the HPV DNA transition types, number of positive results, and the durations of positive results were also analyzed. Results: The proportion of abnormal cytology findings decreased in the following order of transition patterns: persistent, latent, transient, and negative. Among transient patterns, a duration of three years or more significantly correlated with cytology results of non-high grade squamous intraepithelial lesion (HSIL; p<0.001). In the persistent group, duration of five years or more correlated with both non-HSIL and HSIL (p<0.001). Latent group showed no correlation with duration. Irrespective of patterns, having five or more positive results was significantly associated with HSIL (p<0.001). Conclusions: Our findings may contribute to better understanding of HPV infection, interpretation of HPV DNA screening results, and prediction of prognosis according to transition type.

• 한국신재생에너지학회:학술대회논문집
• /
• 2010.11a
• /
• pp.76.2-76.2
• /
• 2010

The gas diffusion layer is the key component of the proton exchange membrane fuel cell because it directly affect to the mass transport mechanism and dynamic behavior of the cell. In this study, the effects of GDL aging on the transient response of the PEM fuel cell is systematically investigated using current step transient response analysis under different stoichiometric ratios and humidity conditions. With GDLs aged by the accelerated stress test, the effects of hydrophobicity and structural changes due to carbon loss in the GDL on the transient response of PEM fuel cells are determined. The degraded GDLs that had uneven hydrophobicity distributions cause local water flooding inside the GDL and induce lower and unstable voltage responses after load changes.

• Proceedings of the KIEE Conference
• /
• 2006.07a
• /
• pp.143-144
• /
• 2006

The recent power systems are very complex and to model them completely is impractical for analysis of electromagnetic transient Therefore areas outside the immediate area of interest must be represented by some form of Frequency Dependent Network Equivalent (FDNE). In this paper a method for developing Frequency Dependent Network Equivalent (FDNE) using S-domain rational Function Fitting is presented and demonstrated. The FDNE is generated by Linearized Least Squares Fitting(LSF) of the frequency response of a S-domain formulation. This Three-port FDNE have been applied to the test AC power system. The electromagnetic transient package PSCAD/EMTDC is used to assess the transient response of the Three-port FDNE developed under different condition. The study results have indicated the robustness and accuracy of Three-port FDNE for analisys of electromagnetic transient and harmonic assessment.