• Fire Science and Engineering
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• v.21 no.2 s.66
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• pp.30-35
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• 2007

The flame retardancies by the addition of metal powder and flame retardant were evaluated to present as the fundamental data to decrease the fire hazard of polymers and life losses by suffocation and poisoning. For this study, the experiments of flame retardancy were conducted as follows : weight loss rate using thermogravimetric analysis, the measurement of the limiting oxygen index(LOI) and char yield. And smoke mass concentration and CO yield were measured. Acrylonitrile butadiene styrene containing metal powder and flame retardant reduced weight loss rate and increased LOI and char yield with the decreased smoke mass concentration and CO yield. It was found that the most effective complex was tricresyl phosphate-Mo complex.

• Food Science and Preservation
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• v.5 no.2
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• pp.138-143
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• 1998

The stowage effects of Satsuma mandarin(Citrus unshiu Marc. var. miyagawa) were investigated by selecting various pretreatmnents; non-tested, wax-coating, paper packaging, 0.02mm cryovac film packaging. Weight loss of film packaging was the lowest among that of others, but decay radio was increased highly at late stages of storage. Soluble solids, moisture content of peel and total sugar were maintained almost constant, but acid content, vitamin C and firmness were reduced gradually during storage at room temperature. For 100 days storage, losses from weight and decay of ton-treated, paper packaging, wax-coating and film packaging were 15.9%, 18.5%, 17.4% and 12.9%, respectively. Acid content was decreased loom 1.28% to 0.81∼0.91% after 100 days storage. Ethylene evolution was increased in a degree after 65 days storage, and the amount was increased repidly afer 115 days. it seemed to be derived from decayed fruits and physiological activities. CO2 content of inner part of fruits was increased between 40∼100 days after storage. Optimum storage period of early variety of Satuma mandarin was regarded for 100days on the basis of appeareance and taste.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.6
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• pp.1018-1025
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• 2011

The improved properties of corrosion for 90Cu10NiFe alloy in natural seawater were explained by sodium diethyl dithio carbamate(NaDDC), namely organic compound, which is reagent for heavy metal extractions of waste water. The efficiency of NaDDC as corrosion inhibitor for 90Cu10NiFe alloy has been investigated in seawater after immersion in various concentrations of NaDDC solutions for 12~36hrs at pH 8.2 by weight loss test and electrochemical techniques including potentiodynamic polarization and SEM-EDS measurements. The results showed that the corrosion resistance of 90Cu10NiFe alloy improves with the increasing concentration of NaDDC but it did not improves with increasing time any more, so the highest inhibition efficiency was 93% at 100mg/L, 36hrs. The results obtained from weight losses and corrosion rates in polarization curve measurements were in good agreement. Therefore, it showed that NaDDC is a good inhibitor for copper corrosion of 90Cu10NiFe alloy.

• Proceedings of the KIEE Conference
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• 2005.10c
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• pp.17-19
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• 2005

Variety of methods were discussed to reduce the cogging force in tubular permanent magnet type linear single phase AC generator. In paticular, the proposed methods depend on the variations of the permanent magnet construction. These methods Include two approaches in the form of sloped magnets, and conical magnets in addition to the conventional method of varying the magnet length. The undesired cogging force ripples were calculated by a two dimensional Finite Element Method(FEM). Moreover, the generated electromotive force in the stator coils was calculated fur each configuration of the permanent magnet. The experimental results agreed well with those obtained from the FEM-based simulations. Sufficient reduction in the cogging force was achieved over the range of 40% while the root mean square of the output voltage was maintained. It was found that the sloping the permanent magnet decreased the cogging force and at the same time increased the generated rms voltage of the AC generator. The performance of the designed linear AC generator was evaluated in terms of its efficiency, total weight, losses, and power to weight ratio.

• Elastomers and Composites
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• v.38 no.1
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• pp.65-71
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• 2003

Influence of low molecular weight styrene-butadiene rubber (liquid SBR) on properties of a silica-filled styrene-butadiene rubber (SBR) compounds was studied. Viscosity of the silica-filled SBR compound decreased by adding the liquid SBR. The crosslink density decreased and the cure rate became slower as the liquid SBR content increased. The modulus and tensile strength decreased while the elongation at break became longer by increasing the liquid SBR content. The abrasion losses were nearly the same irrespective of the liquid SBR content. This might be due to the improvement of silica dispersion by adding the liquid SBR. Considering the experimental results, it was believed that addition of small amount of the liquid SBR (less than 5 phr) was desirable to improve properties of silica-filled SBR compounds.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.700-702
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• 2002

High-speed brushless permanent magnet machines are good for compressor and aerospace applications, etc. since they are conductive to high efficiency, high power density, small size and low weight. This paper presents 3-phase permanent magnet brushless AC Motor designed for the high-speed drives. Especially, we predicted the inverter high frequency pulse width modulation (PWM) switching caused eddy current losses in a permanent magnet brushless dc motor.

• Tribology and Lubricants
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• v.22 no.6
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• pp.335-341
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• 2006

This paper reports the wear characteristics of two types of coating materials, which are $Cr_2O_3$ and $ZrO_2$, by coated plasma thermal spray method. The wear test was carried out under air, grease, and bearing fluid conditions. The wear testing machine of a pin-on disk type were used to measure friction forces, friction coefficients and the weight losses of the coating specimens on the various sliding velocity and loading condition. The wear surface of specimens were observed by scanning electron microscope (SEM) photographs.

• Proceedings of the KIEE Conference
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• 2003.10b
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• pp.174-176
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• 2003

The power conversion system must be increased switching frequency in order to achieve a small size, a light weight and a low noise. This paper proposes a skillful and a concise PWM DC-DC converter employing both zero voltage and zero current high frequency switching(ZVCS) operation. The Proposal ZVCS circuit is composed with resonant circuit using active resonant condenser. And this circuit provides switches with ZVS and ZCS by quasi resonant only that switching transients appear. This operation results in reduction of stress and losses in the power devices and resonant components. Some simulation results are included to confirm the validity of the analytical results.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.6
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• pp.1094-1099
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• 1998

Newly introduced aseptic process for cooked rice was optimized by evaluating the process parameters. The optimal conditions were as follows: ratio of washing water to rice, 3:1 by weight; steeping at 20oC for 20min; heat shock at 140oC for 7sec with 8 repetitions; addition of 0.2% glucono lactone solution; cooking at 103oC for 30min. The final products were incubated at 37oC and 50oC for 8 weeks and no spoilage was occurred at both temperatures. Furthermore, any significant losses of sensory and physicochemical qualities were not observed.

• Journal of Photoscience
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• v.12 no.2
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• pp.95-100
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• 2005

We have synthesized an azobenzene-containing polymer (PEA) and a stilbene-containing polymer (PAS) with second-order nonlinear properties. The second harmonic coefficient ($d_{33}$) of the poled polymer films was 84 and 36 pm/V for of PEA and PAS, respectively. The poled state of these polymers was stable at least up to 30 h at room temperature. $T_g$ of these polymers appeared in the range from 120 to $160^{\circ}C$ and onset of initial weight losses in the range from 260 to $270^{\circ}C$. Silicon moieties in the main chain enhanced the solubility of PEA and PAS in common organic solvents such as chloroform, N-methylpyrrolidinone (NMP), N, N-dimethylformamide (DMF), etc.