• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.5
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• pp.7-15
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• 2022

Since the direct and indirect damage caused by the fire in the underground utility tunnel will cause great damage to society as a whole, it is necessary to make efforts to prevent and control it in advance. The most of the fires that occur in cables are caused by short circuits, earth leakage, ignition due to over-current, overheating of conductor connections, and ignition due to sparks caused by breakdown of insulators. In order to find the cause of fire at an early stage due to the characteristics of the underground utility tunnel and to prevent disasters and safety accidents, we are constantly managing it with a detection system using image analysis and making efforts. Among them, a case of developing a fire detection system using CCTV-based deep learning image analysis technology has been reported. However, CCTV needs to be supplemented because there are blind spots. Therefore, we would like to develop a high-performance acoustic-based deep learning model that can prevent fire by detecting the spark sound before spark occurs. In this study, we propose a method that can collect sound in underground utility tunnel environments using microphone sensor through development and experiment of prototype module. After arranging an acoustic sensor in the underground utility tunnel with a lot of condensation, it verifies whether data can be collected in real time without malfunction.

• Journal of the Korean Electrochemical Society
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• v.25 no.1
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• pp.42-49
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• 2022

In this study, the surface protection film based on organic-inorganic composite is manufactured for suppressing lithium dendrite growth, and the film is applied on the surface of Li metal negative electrode for lithium metal batteries (LMBs). The film is consist of the polyvinylidene fluoride (PVDF) polymeric binder which has good mechanical strength and high electrochemical stability, and carbon black (Super-P) which has outstanding electrical conductivity as the inorganic compound. First, in order to confirm the suppression of the internal short circuit by the lithium dendrite, the time required for the short circuit is measured while a constant current is continuously applied. As a result, the internal short circuit is delayed in proportion to the carbon black content of the film, and it is significantly delayed than bare Li metal electrode which does not use protection film. The cycle performance of the thick protection film (8 ㎛), is worse than that of the thin film (4 ㎛). However, as the carbon black content of the film increased, the cycle performance is improved. Thus, the surface protection film based on carbon black/PVDF composite can delay the internal short circuit, and has low overvoltage during the cycle. However, more stable cycle performance needs to be built through further improvements.

• Journal of Space Technology and Applications
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• v.2 no.2
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• pp.104-120
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• 2022

The Small Scale magNetospheric and Ionospheric Plasma Experiment (SNIPE)'s scientific goal is to observe spatial and temporal variations of the micro-scale plasma structures on the topside ionosphere. The four 6U CubeSats (~10 kg) will be launched into a polar orbit at ~500 km. The distances of each satellite will be controlled from 10 km to more than ~1,000 km by the formation flying algorithm. The SNIPE mission is equipped with identical scientific instruments, Solid-State Telescopes(SST), Magnetometers(Mag), and Langmuir Probes(LP). All the payloads have a high temporal resolution (sampling rates of about 10 Hz). Iridium communication modules provide an opportunity to upload emergency commands to change operational modes when geomagnetic storms occur. SNIPE's observations of the dimensions, occurrence rates, amplitudes, and spatiotemporal evolution of polar cap patches, field-aligned currents (FAC), radiation belt microbursts, and equatorial and mid-latitude plasma blobs and bubbles will determine their significance to the solar wind-magnetosphere-ionosphere interaction and quantify their impact on space weather. The formation flying CubeSat constellation, the SNIPE mission, will be launched by Soyuz-2 at Baikonur Cosmodrome in 2023.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.32 no.2
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• pp.77-82
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• 2022

Recently, research on the development of low-cost/high-efficiency water electrolysis catalysts to replace noble metal catalysts is being actively conducted. Since overvoltage reduces the overall efficiency of the water splitting device, lowering the overvoltage of the oxygen evolution reaction (OER) is the most important task in order to generate hydrogen more efficiently. Currently, noble metal catalysts show excellent characteristics in OER performance, but they are experiencing great difficulties in commercialization due to their high price and efficiency limitations due to low reactivity. In this study, a water electrolysis catalyst Ni-MWCNT was prepared by successfully doping Ni into the MWCNTs structure through the pulsed laser ablation in liquid (PLAL) process. High resolution-transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS) were performed for the structure and chemical composition of the synthesized Ni-MWCNT. Catalytic oxygen evolution reaction evaluation was performed by linear sweep voltammetry (LSV) overvoltage characteristics, Tafel slope, electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and Chronoamperometry (CA) was used for measurement.

• Journal of the Microelectronics and Packaging Society
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• v.30 no.1
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• pp.79-89
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• 2023

Development of efficient and stable electrocatalysts for oxygen evolution reaction (OER) under acidic conditions is desirable goal for commercializing proton exchange membrane (PEM) water electroyzer. Herein, we report iridium-doped hydrogenated titanate (Ir-HTO) nanobelts as a promising catalyst with a low-Ir content for the acidic OER. Addition of low-Ir (~ 3.36 at%) into the single-crystalline HTO nanobelts with large exposed {100} facets significantly boost catalytic activity and stability for OER under acidic conditions. The Ir-HTO outperforms the commenrcial benchmark IrO₂ catalyst; an overpotential for delivering 10 mA cm^-2 current density was reduced to about 25% for the Ir-HTO. Moreover, the catalytic performance of Ir-HTO is positioned as the most efficient electrocatalyst for the acidic OER. An improved intrinsic catalytic activity and stability are also confirmed for the Ir-HTO through in-depth electrochemical characterizations. Therefore, our results suggest that low-Ir doped single-crystalline HTO nanobelts can be a promising catalyst for efficient and durable OER under acidic conditions.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.19 no.2
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• pp.111-116
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• 1983

In order to furnish the fundamental data for the domestic production of magnetic compass and the prescription of standardization about it in Korea, authors made the helmholtz coil and investigated the characteristics of them. Subsequently, the damping curves of T190 and T165 compasses in the helmholtz coil were measured and analyzed the performance of those compass. The results obtained are as follows; 1. The relation between electric current (I sub I) to flow in the helmholtz coils, that the thickness of coil is 1mm, diameter 1m, winding number 117, and intensity of magnetic field is presented as follows. Vertical magnetic force: Z(Gauss)=0.34+1.506 I sub(i) Horizontal magnetic force: H(Gauss)=0.183+1.506 I sub(i) 2. Period of T190 compass is longer than T165 compass in all horizontal magnetic force. In the amplitude, the former is larger than the latter above 0.08 Gauss, but this phenomenon is opposed to that below 0.08 Gauss. 3. As the porizontal magnetic force is intensive, period of magnetic compass is short, amplitude is large, and damping degree and damping factor are small. The time elapsed to the principal points of damping curve is proportional to the -0.65 power of the horizontal magnetic force.

• Analytical Science and Technology
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• v.19 no.6
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• pp.482-489
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• 2006

Two electrode-based lactate biosensor was prepared by immobilizing lactate oxidase (LOD) obtained from pediococcus species in a poly(vinyl alcohol). Hydrogen peroxide ($H_2O_2$) produced by the reaction of lactate and LOD was detected on the Pt-black that was electrochemically deposited on the Au electrode. Sensors fabricated with Pt-black deposited Au electrode provided a high current of $H_2O_2$ oxidation at a substantially lowered applied potential (+300 mV vs. Ag/AgCl), resulting in reduced interferences from easily oxidizable species such as ascorbic acid, acetaminophen, and uric acid. An outer membrane is formulated by adjusting water uptake of hydrophilic polyurethane (HPU). The sensor performance was evaluated in vitro with both flow-through arrangement and static mode. The sensor showed a linear range from 0.1 mM to about 9.0 mM in 0.05 M phosphate buffer (pH 7.6) containing 0.05 M NaCl. Storing the sensors prepared in this work at $4^{\circ}C$ buffer solution while not in use, they provided same electrochemical performance for more than 25 days.

• Korean Journal of Soil Science and Fertilizer
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• v.8 no.2
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• pp.105-111
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• 1975

Nitrogen efficiency for grain yield(E) and its relation to grain yield(Y), harvesting index(HI), percent translocation of nitrogen from straw to grain(T), nitrogen uptake amount(N), concentration in grain (GN%) or straw (SN%) and total dry matter yield (TY) among rice varieties (Oryza sativa, old and new varieties) were investigated at four nitrogen nutritional status (high and low fertilizer levels in high and low fertility fields) by simple correlation analysis. Relation between any two of above parameters or total dry matter yield (TY) and nitrogen efficiency for total dry matter yield (TE) was also investigated. 1. E is significantly and positively correlated with T, Y, HI but negatively with SN%, N, GN% and in negative trend with TY. 2. T is significantly and positively with GN% or Y, but negatively with SN%. 3. TE is significantly and positively correlated with TY but negatively with N. 4. The order of E among varieties showed consistency among different nitrogen nutritional environments. 5. From the above facts it was concluded that high yielding varieties have high nitrogen efficiency due to high percent translocation of nitrogen from straw to grain, subsequent low nitrogen concentration in straw and that translocated nitrogen in grain is greatly diluted with photosynthates. 6. Reported physiological characteristics of newly bred high yielding IR lines are well accordance with their high nitrogen efficiency and rice breeding was a selection on the basis of nitrogen efficiency. 7. It is postulated that high nitrogen efficiency varieties for yields have high nitrogen efficiency for root growth in early stage so that uptake more efficient soil nitrogen in later growth stage.

• The Journal of the Korea Contents Association
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• v.10 no.9
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• pp.267-275
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• 2010

Quality management of an x-ray unit drastically differs according to the type of establishment of medical institutions. Many primary medical institutions have it, but they do not pay much attention to quality management. In the study, Gyeongbuk area has been divided into four zones from January 4, 2010 to September 3, 2010, and four places were designated by city. Among medical institutions located at a total of 16 sites, the target was 8 places with X-ray emission equipment 10 years or more in use as well as 8 places with X-ray emission equipment less than 10 years in use. The 5 essential items of quality control were tested. In the test that checked for equipment it was found that sites with X-ray emission equipment 10 years or more in use didn't have ground connection (6.25%) while all of them passed the current leak test. In the exposure dose reproducibility test 4 sites with X-ray emission equipment 10 years or more in use (25%) and 1 site with X-ray emission equipment less than 10 years in use didn't pass the test. In the KVp accuracy test 5 sites with X-ray emission equipment 10 years or more in use (31.25%) and 2 sites with X-ray emission equipment less than 10 years in use (12.5%) didn't pass the test. In the tube current and tube current amount test 3 sites with X-ray emission equipment 10 years or more in use (18.75%) and 1 site with less than 10 years in use (6.25%) didn't pass the test. According to the findings of the present research, quality control at medical institutions with X-ray equipment 10 years or more in use was poorer than medical institutions with X-ray equipment less than 10 years in use. In this regard, administrative and technical measures need to be taken as soon as possible. In addition, owners of medical clinics or unit managers need to raise awareness, and it is necessary to revise a regular test cycle every year or every two years if they have old equipment or if the equipment is not used on a frequent basis. And it is also important to provide regular educational programs for quality management.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.6
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• pp.568-575
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• 1991

The morpho-anatomical characteristics of panicle in rice plant is generally correlated with the number of spikelets and grain weight per panicle. For the increase of grain yield potential in rice, a low -tillering plant type with large panicles has been suggested as an ideotype. This study was conducted to investigate the panicle morphology and peduncle anatomy of different tillers within a plant in low -and high-tillering cultivars and their relationships on the number of spikelets and grain weight per panicle. A low-tillering, large panicled IR25588 was compared with a high-tillering. small panicled IR58. IR25588 had more inner(IVB) and outer vascular bundles (OVB). bigger peduncle diameter and peduncle thickness just below the panicle neck node than IR58. The top six tillers(M. P1, P2, P3. P4 and S1P2) within a plant had more IVB and OVB. larger peduncle diameter and thickness than the rest of the tillers in both cultivars. Tillers that emerged earlier had more IVB and OVB than tillers that emerged Jater. The total number of primary and secondary rachis-branches of IR25588 was much higher than that of IR58. IR25588 had more number of spikelets per panicle than IR58. and the top six panicles showed more spikelets per panicle than the rest of the panicles in both cultivars. The peduncle diameter was more important than peduncle thickness on the spikelet differentiation and panicle weight. especially in low-tillering cultivars. The number of IVB and OVB were highly correlated with the number of rachis-branches. spikelets and grain weight per panicle. The number of spikelets per IVB and spikelets per primary branch were higher in IR25588 than IR58 indicating the higher sink strength in low -tillering with large panicled cultivars than in high-tillering with small panicled cultivars. Based on the morpho-anatomical characteristics of a low-tillering cultivar and the top six tillers within a plant. the present results could be support that 'a low-tillering sturdy culms with large panicles' is an ideo-type of rice plant for increasing grain yield potential.potential.