• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.2
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• pp.111-116
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• 2001

Poly-Si TFT's(Polysilicon thin filmtransistors) have been actively studied due to their applications in active matrix liquid crystal displays and active pull-up devices of CMOS SRAM's. For such applications, the leakage current has to be in the range of sub-picoampere. However, poly-Si TFT's suffer from anomalous high leakage currents, which is attributed to the emission of the traps present at gain boundaries in the drain junction. The leakage current has been analyzed by the field emission via grain-boundary traps and thermionic field emission over potential barrier located at the grain boundary. We found that the models proposed before are not consistent with the experimental results at far as drain-offset poly-Si TFT's we fabricated concern. In this paper, leakage current of drain-offset poly-Si TFT's with different offset lengths was studied. A conduction model based on the thermionic emission of the tunneling electrons is developed to identify the leakage mechanism. It was found that the effective grain size of the drain-offset region is important factor in the leakage current. A good agreement between experimental and simulated results of the leakage current is obtained.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.6
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• pp.828-833
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• 2014

Grid connected transformerless solar power generation system is frequently used with the benefits of cost and efficiency. However, significant DC leakage current can flow from the DC line into the ground with dielectric breakdown in the transformerless solar power generation system. The leakage current occurred in the DC line causes accidents such as fire and electric shock on human. To resolve this problem, high sensitivity DC leakage current sensor is needed. But recently the studies on safety of DC line are not performed. In this paper, a high sensitivity DC leakage current sensor that can detect DC leakage current in solar power generation system, is proposed. Based on the studies, DC leakage current sensor is fabricated and characteristic tests are carried out. Finally, the accuracy of sensor performance is verified by leakage current experiments in solar power generation system.

• Nuclear Engineering and Technology
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• v.55 no.4
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• pp.1528-1539
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• 2023

Since the leakage of sodium in an SFR (sodium-cooled fast reactor) causes an explosion upon reaction with air and water, sodium leakages represent an important safety issue. In this study, a novel technique for improving the reliability of sodium leakage detection applying DDVR (dynamic data validation and reconciliation) is proposed and verified to resolve this technical issue. DDVR is an approach that aims to improve the accuracy of a target system in a dynamic state by minimizing random errors, such as from the uncertainty of instruments and the surrounding environment, and by eliminating gross errors, such as instrument failure, miscalibration, or aging, using the spatial redundancy of measurements in a physical model and the reliability information of the instruments. DDVR also makes it possible to estimate the state of unmeasured points. To validate this approach for supporting sodium leakage detection, this study applies experimental data from a sodium leakage detection experiment performed by the Korea Atomic Energy Research Institute. The validation results show that the reliability of sodium leakage detection is improved by cooperation between DDVR and hardware measurements. Based on these findings, technology integrating software and hardware approaches is suggested to improve the reliability of sodium leakage detection by presenting the expected true state of the system.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.561-564
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• 2007

This case was successfully constructed as a leakage prevention case of primary 2-arch tunnel located in Anyang, Gyungkido. The leakage of primary 2-arch tunnel was observed at middle wall of tunnel and girder of tunnel. Such a leakage of primary 2-arch tunnel generally occurred due to the damage of the waterproof membrane constructed on the middle wall during the blasting works of right and left tunnel after construction of the middle wall. As the leakage, icicles hanged from girder of tunnel in the winter. In such phenomenon, the risk of the traffic accident in the tunnel was high. In this case, leakage prevention works were successfully constructed using the heat insulated drainage.

• 유체기계공업학회:학술대회논문집
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• 2003.12a
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• pp.143-148
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• 2003

This study was experimentally performed in order to estimate the errors due to the leakage of transmitter gaugelines in the orifice flow meter for natural gas. It would be a serious problem in safety if a large quantity of leak was occurred at the tubes or fittings like valve. But in most cases the safety problems might be rarely happened because the gas leak detectors could be operated in advance and the various kinds of inspection would be also fulfilled periodically. If the leakage was occurred continuously with an undetectable amount at the gaugelines for measuring the pressure or the differential pressure(DP), the amount of leakage might be an error or an unaccounted flow(UAE). In addition if the measuring value of pressure or DP were affected by the leakage, it might also be a measurement error. The experiments were performed to estimate the amount of leakage and to check the DP changes if it exited. First, through the measurement of the air pressure changes in the airtight container connected to a transmitter with gaugelines as the time passed, the amount of leakage causing from the fittings of gaugelines was roughly estimated. As changing the leak position of the gaugeline, the leak was intentionally made to break out. The variance of DP was checked as controlling the extent of leakage and compared to no leak conditions. Consequently, under the normal maintenance conditions, the result represented that the amount of leakage causing from the gaugelines was insignificant and also the DP changes on leakage conditions were too small to cause the errors of measurements.

• Journal of the Korea Institute of Building Construction
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• v.6 no.1 s.19
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• pp.87-91
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• 2006

Since water leakage and cracks are not the source of serious problems such as long-term lowering of performance and durability of a stricture, including damages to operating facilities of a structure, damages to internal finishing materials, exhibition, and goods, and pollution of residential environment, they might have led to development of positive coping skills; however, an instant loss of lives or property due to earthquake, explosion, typhoon, or a fire was indeed neglected. In these days, repair materials for leakage cannot help but being taken in temporary way without any noticeable countermeasure. This kind of repair is socially criticized many times that is defective construction even if this costs a lot. It was not arrange the standard for construction methods of sealer of injection type for leakage maintenance, even it has been used various type of construction methods for leakage part. In conclusion, we suggest that the construction methods of sealer of injection type for leakage maintenance for leakage to establish the leakage repairing technology as increase of structure demand. Therefore, it would be possible to provide a stage-by-stage solution by developing systematic research activities among the industry, schools, and research institutes to spread maintenance management techniques globally through technical solution to water leakage and cracks, acquisition of structural safety with prolonged durability for life cycle, reduction of water leakage repair expense s, and so on.

• Journal of Korea Water Resources Association
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• v.50 no.9
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• pp.609-616
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• 2017

In this study, algorithm for the selecting the optimum monitoring location and leakage detection algorithm based on back tracing calculation method were developed and verified by the experiments in pilot plant of water distribution system. First of all, optimum monitoring locations were selected and pressure changes were measured due to artificial leakage by pressure gauges in pilot plant. Simulations of leakage detection was performed for the verification of back tracing calculation method as a leakage detection method. From the results, it was found that leakage locations and leakage amount were exactly estimated. Various leakage amount from $0.0005m^3/s$ to $0.0018m^3/s$ were reproduced and leakage location was detected by back tracing calculation method. It was verified that back tracing calculation method as a leakage detection method is effective.

• Speech Sciences
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• v.13 no.1
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• pp.117-128
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• 2006

The two-channel Generalized Sidelobe Canceller (GSC) scheme suffers from the presence of leakage signal in the reference channel. The leakage signal is caused by the dissimilar impulse responses between microphones, and different paths from speech source to microphones. Such leakage is detrimental to speech enhancement of the GSC since the desired reference signal becomes corrupted. In order to suppress the signal leakage, two matrix injection methods are proposed. In the first method, a simple gain compensation matrix is used. In the second, a projection matrix for reducing the error between the actual and the ideal primary and reference signals, is used. This paper describes the performance degradation resulting from leakage, and proposes effective methods to resolve the problem. Representative experiments were conducted to demonstrate the effectiveness of the proposed methods on recorded speech and noise in an actual automobile environment.

• The Korean Journal of Nuclear Medicine
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• v.33 no.2
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• pp.184-188
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• 1999

Although cerebrospinal fluid leakage is suggested as one of the causes of spontaneous intracranial hypotension, only a few cases with direct evidence of cerebrospinal fluid leakage on radionuclide cisternography have been reported in the literature. Indirect evidences of cerebrospinal fluid leakage such as early visualization of the soft tissue and bladder or delayed migration of radiotracer have been observed in most patients with spontaneous intracranial hypotension. We report a case of spontaneous intracranial hypotension in which cerebrospinal fluid leakage was directly demonstrated by early dynamic imaging of spine on radionuclide cisternography. We suggest that early dynamic imaging of spine is an important adjunctive procedure in detecting cerebrospinal fluid leakage in patients with spontaneous intracranial hypotension.

• Tribology and Lubricants
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• v.25 no.3
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• pp.150-156
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• 2009

Precise leakage prediction for annular type seals of turbomachinery is necessary for enhancing their efficiency and various prediction methods have been developed. As the seal passage is designed intricately, the analysis based on Bulk-flow concept which has been mainly used in predicting seal leakage is limited. In order to improve the seal leakage prediction, full Navier-Stokes Equations with turbulent model derived in the seal flow passage have to be solved. In this study, 3D CFD (Computational Fluid Dynamics) analysis has been performed for predicting leakage of various non-contact type anular seals using FLUENT. Compared to the results by Bulk-flow model analysis, experiment, and 2D CFD analysis, the result of 3D CFD analysis shows improvement in predicting seal leakage, especially for the parallel grooved pump seal.