• Journal of Aerospace System Engineering
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• v.12 no.6
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• pp.17-22
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• 2018

The amount of fuel, which affects aircraft endurance, needs to be measured accurately. This paper deals with the implementation of a fuel quantity measurement system that consists of capacitive fuel sensor, DAQ board, and Labview software. The main circuit of the implemented system for measuring fuel quantity is simulated with Pspice to identify parameters, which are related to the change of fuel quantity. After simulation, we established that Vrms changes with the variation of fuel amount. The Vrms, which is the output of fuel sensor, is transmitted to the Labview software via the DAQ board of the implemented fuel quantity measurement system. The fuel quantity is also calculated using this software. The present simulation results indicated that the accuracy of the implemented fuel quantity measurement system improved with the filter application.

• Resources Recycling
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• v.28 no.2
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• pp.31-39
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• 2019

The pelletizing of printed circuit board (PCB) sludge was researched for copper recovery in pyrometallurgical process. This pelletizing was carried out by using self-manufactured compression-type apparatus after pre-treatments (drying, water scrubbing, size classification) were proceeded. The physical properties (compression strength and drop-breakage test) were tested with a change of sludge sizing and the number of compression. In the case of using the undersized sludge of #140, its properties were improved to 0.6 MPa and 9.3 times. Moreover, they increased to 0.82 MPa and 19.0 times by using the #140 ~ 325 sludge. These imply that the packing density increases due to the elimination of large-sized sludge (#140), and also the weight of required binder decreases by the removal of fine-sized sludge (#325).

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.219-220
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• 2016

A power management system (PMS) has been an important part in a ship integrated control system. To evaluate a PMS for a liquefied natural gas carrier (LNGC), this research proposes a real-time hardware-in-the-loop simulation (HILS), which is composed of major component models such as turbine generator, diesel generator, governor, circuit breaker, and 3-phase loads on MATLAB/Simulink. In addition, FPGA based control console and main switchboard (MSBD) are constructed in order to develop an efficient control and a similar real environment in an LNGC PMS. A comparative study on the performance evaluation of PMS functions is conducted using two test cases for sharing electric power to consumers in an LNGC. The result shows that the proposed system has a high verification capability for the operating function and failure insertion evaluation as a PMS simulator.

• Journal of Digital Convergence
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• v.17 no.5
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• pp.217-223
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• 2019

A study in predicting defects of spot welding in real time in automotive field is essential for cost reduction and high quality production. Welding quality is determined by shear strength and the size of the nugget, and results depend on different independent variables. In order to develop the real-time prediction system, multiple regression analyses were conducted and the two dependent variables were obtained with sufficient statistical results with three independent variables, however, the quality prediction by the regression formula could not ensure accuracy. In this study, a multi-layer neural network circuit was constructed. The neural network by 10 dynamic resistance variables was constructed with three hidden layers to obtain execution functions and weighting matrix. In this case, the neural network was established with three independent variables based on regression analysis, as there could be difficulties in real-time control due to too many input variables. As a result, all test data were divided into poor, partial, and modalities. Therefore, a real-time welding quality determination system by three independent variables obtained by multiple regression analysis was completed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.2
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• pp.268-275
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• 2020

A lightweight hardware design of self-timed ring based true random number generator (TRNG) suitable for information security applications is described. To reduce hardware complexity of TRNG, an entropy extractor with feedback structure was proposed, which minimizes the number of ring stages. The number of ring stages of the FSTR-TRNG was determined to be a multiple of eleven, taking into account operating clock frequency and entropy extraction circuit, and the ratio of tokens to bubbles was determined to operate in evenly-spaced mode. The hardware operation of FSTR-TRNG was verified by FPGA implementation. A set of statistical randomness tests defined by NIST 800-22 were performed by extracting 20 million bits of binary sequences generated by FSTR-TRNG, and all of the fifteen test items were found to meet the criteria. The FSTR-TRNG occupied 46 slices of Spartan-6 FPGA device, and it was implemented with about 2,500 gate equivalents (GEs) when synthesized in 180 nm CMOS standard cell library.

• Journal of the Korea Convergence Society
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• v.12 no.5
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• pp.17-22
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• 2021

Eco-friendly magnesium-air battery is a kind of metal-air battery known as a primary battery with a very high theoretical discharge capacity. This battery is also called a metal-fuel cell from the viewpoint of using oxygen in the atmosphere as a cathode active material and magnesium alloy as a fuel. Since battery performance is determined by the properties of the magnesium alloy used as a anode, more research and development of the magnesium alloy electrode as a anode material are required in order to commercialize it as a high-performance battery. In this study, the commercialized magnesium alloys(AZ31, AZ61) were selected and then electrochemical measurements and discharge test were conducted. Electrochemical properties of magnesium alloys were investigated by OCP changes, Tafel parameters and CV measurement, and the feasibilities of AZ61 alloy with excellent discharge capacity(1410mAhg^-1) as electrode materials were evaluated through CC discharge experiments.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.28 no.2
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• pp.143-149
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• 2022

PCS needs to freely switch AC and DC to connect the battery, external AC loads and renewable energy in both directions for energy efficiency. Whenever converting happens, power loss inevitably occurs. Minimization of the power loss to save electricity and convert it for usage is a very critical function in PCS. PCS plays an important role in the ESS(Energy Storage System) but the importance of stabilizing semiconductors on PCB(Printed Circuit Board) should be empathized with a risk of failure such as a fire explosion. In this study, the temperature variation inside PCS was reviewed by cooling fan on top of PCS, and the vibration characteristics of PCS were analyzed during truck transportation for reliability of the product. In most cases, a cooling fan is mounted to control the inner temperature at the upper part of the PCS and components generating the heat placed on the internal aluminum cooling plate to apply the primary cooling and the secondary cooling system with inlet fans for the external air. Results of CFD showed slightly lack of circulating capacity but simulated temperatures were durable for components. The resonance points of PCS were various due to the complexity of components. Although they were less than 40 Hz which mostly occurs breakage, it was analyzed that the vibration displacement in the resonance frequency band was very insufficient. As a result of random-vibration simulation, the lower part was analyzed as the stress-concentrated point but no breakage was shown. The steel sheet could be stable for now, but for long-term domestic transportation, structural coupling may occur due to accumulation of fatigue strength. After the test completed, output voltage of the product had lost so that extra packaging such as bubble wrap should be considered.

• Journal of Electrochemical Science and Technology
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• v.12 no.4
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• pp.431-439
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• 2021

This research work aims to investigate the effect of the aerobic bacterium, Pseudomonas aeruginosa on the mechanical and electrochemical properties of the 316L stainless steel and α-brass. These properties of both the alloys were determined after 7 days of exposure to the controlled and inoculated media at 37℃. The microstructural and electrochemical test results revealed the deleterious effects of Pseudomonas aeruginosa. After exposure to the inoculated medium, the scanning electron microscopy (SEM) results showed the larger pitting and formation of relatively dense biofilm on α-brass compared to 316L stainless steel. The tensile strength and hardness of 316L stainless steel were slightly affected after exposure to the controlled and inoculated media. After exposure to the controlled medium and inoculated media, the tensile strength of the α-brass was least affected but a significant decrease in the hardness (from 165 HV to 124 HV) was observed due to the severe attack induced by the Pseudomonas aeruginosa. Similarly, the open-circuit potential of the 316L stainless steel in the inoculated medium was measured to be less active (-410 mV vs Ag/AgCl) than α-brass (-550 mV vs Ag/AgCl). In the inoculated medium, potentiodynamic polarization curves confirmed the severe attack of Pseudomonas aeruginosa on α-brass (7.15 × 10^-2 mm/year) compared to 316L stainless steel which registered a corrosion rate of 5.14 × 10^-4 mm/year.

• BMB Reports
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• v.56 no.3
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• pp.178-183
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• 2023

Huntington's disease (HD) is a neurodegenerative disorder, of which pathogenesis is caused by a polyglutamine expansion in the amino-terminus of huntingtin gene that resulted in the aggregation of mutant HTT proteins. HD is characterized by progressive motor dysfunction, cognitive impairment and neuropsychiatric disturbances. Histone deacetylase 6 (HDAC6), a microtubule-associated deacetylase, has been shown to induce transport- and release-defect phenotypes in HD models, whilst treatment with HDAC6 inhibitors ameliorates the phenotypic effects of HD by increasing the levels of α-tubulin acetylation, as well as decreasing the accumulation of mutant huntingtin (mHTT) aggregates, suggesting HDAC6 inhibitor as a HD therapeutics. In this study, we employed in vitro neural stem cell (NSC) model and in vivo YAC128 transgenic (TG) mouse model of HD to test the effect of a novel HDAC6 selective inhibitor, CKD-504, developed by Chong Kun Dang (CKD Pharmaceutical Corp., Korea). We found that treatment of CKD-504 increased tubulin acetylation, microtubule stabilization, axonal transport, and the decrease of mutant huntingtin protein in vitro. From in vivo study, we observed CKD-504 improved the pathology of Huntington's disease: alleviated behavioral deficits, increased axonal transport and number of neurons, restored synaptic function in corticostriatal (CS) circuit, reduced mHTT accumulation, inflammation and tau hyperphosphorylation in YAC128 TG mouse model. These novel results highlight CKD-504 as a potential therapeutic strategy in HD.

• Progress in Superconductivity and Cryogenics
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• v.8 no.2
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• pp.29-32
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• 2006

An advanced superconducting fault current limiter (SFCL) using $high-T_c$ superconducting (HTS) wire has been developed. The SFCL has a non-inductively wound magnet for reducing loss in normal state. Two types of non-inductively wound magnets, the solenoid type and the pancake type, were designed and manufactured by using Bi-2223 wire in this research. Short-circuit tests of the magnets were performed in sub-cooled $LN_2$ cooling system of 65 K. The magnets are thermally more stable and have a higher critical current in 65 K sub-cooled $LN_2$ cooling system than in 77 K saturated one. Because the resistivity of matrix at 65 K is lower than the resistivity at 77 K, the magnets generate a small resistance to reduce the fault current when the quench occurs. The magnets could limit the fault current to low current level with such a small resistance. The current limiting characteristic of the magnets was analyzed from the test result. The solenoid type was wound in parallel to make it non-inductive. The pancake type was also connected in parallel to be compared with the solenoid type in the same condition. The solenoid type was found to have a good thermal stability compared with the pancake type. It also had as large resistance as the pancake type to limit the fault current in sub-cooled $LN_2$ cooling system.