• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.1
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• pp.30-35
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• 2000

The pulsed plasma wire-plate reactor was analyzed on the basis of experiment, EMTP simulation and modelling method. Though the reactor has a non-linear impedance characteristics, we demonstrate that the reactor impedance can be approximately analyzed with the measured initial capacitance and average resistive component of flat zone. Using this modelling method, the influence of the reactor capacitance on the impedance matching between pulse generator and reactor can be investigated. From this, we found that the energy of 95% was delivered form pulse generator to reactor at the ratio of $C_r/C_p\cong 0.3,\; where\; C_p\; is\; pulse\; generator\; capacitance, C_r$ is reactor capacitance.

• Journal of the Korean Wood Science and Technology
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• v.46 no.4
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• pp.309-314
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• 2018

Size reduction is an important pre-processing operation for utilizing biomass as a sustainable resource in industrial-scale energy production and as a raw material for other industries. This work investigates the size reduction characteristics of air-dried Miscanthus sacchariflorus Goedae-Uksae 1 (Amur silver grass) via image processing and identifies the morphological characteristics of comminuted and screened M. sacchariflorus. At chopping lengths of 18, 40, 80, and 160 mm, 81%, 77%, 78%, and 76% of the particles, respectively, passed through a 4-mm sieve. Even a knife mill with a very small screen aperture (>1 mm) admitted over 10% of the particles. The average circularity and aspect ratio of the particles were <0.30 and >10, respectively. These results confirm that in all preparation modes, most M. sacchariflorus particles were needle-like in shape, irrespective of the type of preparation.

• Electrical & Electronic Materials
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• v.9 no.6
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• pp.593-599
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• 1996

Laser scribing of silicon plays an important role in metallization including the grid pattern and the front surface geometry which means aspect ratio of metal contacts. To make a front metal electrode of buried contact solar cell, we used ND:YAG lasers that deliver average 3-4W at TEM$\_$00/ mode power to sample stage. The Q-switched Nd:YAG laser of 1.064 gm wavelength was used for silicon scribing with 20-40.mu.m width and 20-200.mu.m depth capabilities. After silicon slag etching, the groove width and depth for buried contact solar cell are -20.mu.m and 30-50.mu.m respectively. Using MEL 40 Nd:YAG laser system, we can scribe the silicon surface with 18-23.mu.m width and 20-200.mu.m depth controlled by krypton arc lamp power, scan speed, pulse frequency and beam focusing. We fabricated a buried contact Silicon Solar Cell which had an energy conversion efficiency of 18.8 %. In this case, the groove width and depth are 20.mu.m and 50.mu.m respectively.

• Journal of the Korean Ceramic Society
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• v.22 no.5
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• pp.76-84
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• 1985

Mechanical property enhancing mechanisms of $Al_2O_3-ZrO_2$ two phase ceramic composites were studied for several compositions of different $ZrO_2$/$Al_2O_3$ ratio. Microstructural analysis of $Al_2O_3-ZrO_3$(pure) composites indicated that pre-existing microcrack due to larger $ZrO_2$ particle at grain boundary extended along alumina grain boundaries within process zone. Microcracks also nucleated when very small $ZrO_2$ particles at the grain boundaries transformed to monoclinic phase at near of main crack tip. These types of microcracks could contribute to the toughening achieved by creating additional crack surface area during crack propagation. Microstructural analyses also showed that the average grain size and abnormal grain size of $Al_2O_3$ were decreased with increasing $ZrO_2$ vol% in $Al_2O_3$ matrix. As a result it could be concluded as follows In TEX>$Al_2O_3-ZrO_3$(pure) system 1. Microcrack nucleation (stress-induced microcracking) and extension was effective mechanism for absorpiton of fracture energy 2, More narrow distribution and smaller grain size of $Al_2O_3$ due to $ZrO_2$particles mainly contributed to main-tatin the strength and hardness.

• Asian-Australasian Journal of Animal Sciences
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• v.7 no.2
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• pp.191-196
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• 1994

Two experiments were conducted to study the effect of using Egyptian mallow leaf meal (EMLM) on growth performance and feed utilization of common carp (Cyprinus carpio L.) in experiment 1. Four diets containing 0, 5, 15 and 25% EMLM were included at the expense of berseem leaf meal and fed to fingerlings of common carp for 98 days. The results showed that the average daily gain, feed intake and feed coefficient ratio (FCR) were improved (p<0.05) with increasing the level of EMLM in the diet. Fish fed 25% EMLM were similar to control fish (30% berseem leaf meal) in the productive value (PPV%). In experiment 2, five diets were prepared to contain: 1) 30% berseem leaf meal, 2) 25% untreated EMLM, 3) 25% cooked EMLM 4) 25% treated EMLM with 0.5% NaOH and 5) 25% treated EMLM with 1% NaOH. The results showed that diet containing EMLM gave the best growth performance and feed utilization. However, diet containing 1% NaOH treated EMLM superior to the other diets in PPV% and energy utilization. Diets containing 0.5% NaOH-treated EMLM or cooked EMLM decreased the protein utilization compared to those containing EMLM.

• Asian-Australasian Journal of Animal Sciences
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• v.7 no.2
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• pp.183-189
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• 1994

Two experiments were made. In experiment 1, four diets containing 0, 5, 15 and 25% washed seaweed meal were prepared to study the effects of incorporating seaweed meal instead of equivalent amounts of berseem leaf meal in fish feeds on growth performance and feed utilization of common carp. The results showed that average daily gain (ADG), specific growth rate (SGR%), dry matter (DM) and ether extract (EE) of the carcasses were decreased (p<0.05) with the increasing level of seaweed meal in the feeds. Inclusion of 5% seaweed meal in the diet gave the best feed conversion ratio (FCR) among all diets, however, protein productive value (PPV) and energy utilization (EU) were decreased (p<0.05) with increasing level of seaweed meal in the diet. In experiment 2, washed seaweed meal was either steam cooked or sprayed with NaOH (0.5% or 1% NaOH) and incorporated in the diets at the level of 25% instead of equivalent amount of berseem leaf meal. The results showed that steam cooked seaweed gave the best (p<0.05) growth performance, FCR and protein efficiency ratios, PER and PPV, for other treatments in descending order were NaOH treated seaweed, washed seaweed and unwashed seaweed.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.589-589
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• 2012

Indium sulfide thin films have been grown onto glass substrates using radio frequency magnetron sputtering at room temperature. The as-deposited film were annealed in nitrogen atmosphere at different temperatures of 100, 200, 300, 400 and $500^{\circ}C$ with an 1 h annealing time. The effect of annealing temperature on composition, structure, morphology and optical properties of the as-grown In2S3 films has been studied. The XRD results indicate that the as-deposited films are composed by a mixture of both cubic ${\alpha}$ and ${\beta}$ crystalline phases, with some fraction of tetragonal phase. The thermal annealing on the films produces the conversion of the cubic crystalline phases to the tetragonal ${\beta}$ one and a crystalline reorientation of the latter phase. The surface morphological analysis reveals that the films grown at $300^{\circ}C$ have an average grain size of ~ 58 nm. These films show a S/In ratio of 0.99. The optical band gap is found to be direct and the films grown at $300^{\circ}C$ shows a higher optical transmittance of 80% and an energy band gap of 2.52 eV.

• Journal of the Korean Ceramic Society
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• v.20 no.3
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• pp.193-198
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• 1983

This experiment has been carried out for the purpose of investigating the effect of $V_2O_5$ and $H_3BO_3$ additives on sintering of magnesium oxide over the temperature range of 1300-150$0^{\circ}C$ MgO powder has been obtained by calcin-ing extra reagent grade magnesium carbonate(basic) at 90$0^{\circ}C$ for 30 minutes. The specimens were prepared by compression with pressure of 700Kg/cm2 then fired at 1300-150$0^{\circ}C$ for 0-5hrs. Sintering behaviour and microstructure of fired specimens were examined. Densification rates obeyed the equation D=K 1n t+C. The ratio of density in case of addition of $V_2O_5$ to theoretical density of pure periclase was 95-99% Activation energy of densification in case of $V_2O_5$ addition was 30.15 Kcal/mole. The range of average grain size in case of addition of $V_2O_5$ was 40-50$\mu\textrm{m}$. $H_3BO_3$ addtivie had not an effect on densification of MgO.

• Journal of the Korea Safety Management & Science
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• v.16 no.4
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• pp.31-40
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• 2014

While Korea had achieved radical growth of construction industry, it also had accumulated problems in material, human and economical loss due to its low quality of safety level. Therefore, not only enterprises but also the nation is putting in a great deal of efforts for construction safety. However, its effect is not satisfiable. This research aims for change of construction cite by introduction of professional Safety Patrol Management System(SPMS) and consideration of its necessity. To consideration of its necessity, we compared and anaylzed average numbers of indicated dangers and safety accident incidences in each construction cites and we researched changes in worker's safety sense. It will establish the suitable design standards and suggest the basic database for estimating disaster and accident ratio.

• 한국태양에너지학회:학술대회논문집
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• 2011.11a
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• pp.74-79
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• 2011

Concentration characteristics of the KIER solar furnace are analyzed with a heat flux measurement technique. Total heat capacity of 40kW was confirmed within 1.04% average error, and the normalized maximum heat flux of 3,452 $kW/m^2$ was proved. Non-Gaussian flux distribution in the vertical direction implies that reflectors should not be random rather inclined downwards. Moreover, we characterized flux distribution variations with furnace blind opening ratio, distance from the focal plane, and misalignment of the measurement system. Based on the results, the heat flux distribution can be simply estimated once reflectivity and direct normal insolation values are known. This study will be helpful to the design and the performance evaluation of receivers or chemical reactors.