• Journal of the Korean Society for Precision Engineering
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• v.19 no.7
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• pp.88-96
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• 2002

High-speed machining is one of the most effective technologies to improve productivity. Because of the high speed and high feed rate, high-speed machining can give great advantages for the machining of dies and molds. This paper describes on the improvement of machining accuracy in high-speed machining. Depth of cut, feed rate and spindle revolution are control factors. The effect of the control factors on machining accuracy is investigated using two-way factorial design.

• Journal of environmental and Sanitary engineering
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• v.13 no.3
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• pp.141-147
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• 1998

Under high temperature and high pressure, cyanogen disinter gration distruction mechanism brought followings results through continuous plug flow reactor system. 1. The temperature was a important reacting factor in cyanogen disintegration. Over $612.8^{\cird}K$ high disintegration rate or 99.99% was shown even under $2000{\;}mg/{\ell}$ cyanogen density. 2. The conditions of cyanogen disintegration was gained through experimenting the supercrietical condition of water in basic. To gain 99.99% disintegration rate under $1000{\;}mg/{\ell}$ early cyanogen density, the pressure showed 52.8 seconds at $523^{\cird}K$ and 84.2 atm and gained $0.56{\;}mg/{\ell}$ operating density. 3. Here is the reaction velocity formula of cyanogen disintegration by hydrolysis: This formula indicates the high possibility of cyanogen disintegration within a short time. And it also implys the potential possibility on treating NBDICOD and the technology in developing the environment cleaning progress as small size automatic controlling equipment.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1488-1489
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• 2007

This paper described the current rating methodology of high voltage connectors used for high efficient vehicles. Typically, temperature rise at rated current has been used to rate power contacts in automotive connector. However, for automotive applications, they are required to meet severe environmental conditions and high connector reliability. Therefore, it is very important to rate correctly an allowable current of automotive connector. We have measured the contact characteristics through current cycling at room temperature and at high temperature, as well as temperature rising and current carrying capacity by de-rating. From the above results, we have developed high reliable contacts with about 80 Amperes.

• Current Applied Physics
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• v.18 no.11
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• pp.1436-1440
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• 2018

SiN and SiCN film production using plasma-enhanced atomic layer deposition (PE-ALD) is investigated in this study. A developed high-power and high-density multiple inductively coupled plasma (multi-ICP) source is used for a low temperature PE-ALD process. High plasma density and good uniformity are obtained by high power $N_2$ plasma discharge. Silicon nitride films are deposited on a 300-mm wafer using the PE-ALD method at low temperature. To analyze the quality of the SiN and SiCN films, the wet etch rate, refractive index, and growth rate of the thin films are measured. Experiments are performed by changing the applied power and the process temperature ($300-500^{\circ}C$).

• The Journal of the Convergence on Culture Technology
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• v.6 no.2
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• pp.15-23
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• 2020

This study aimed to analyze effects of non-regular employment rate and female employment rate on fertility rate in OECD county. We adopted dynamic panel model after classifying OECD county to high and low fertility rate. The results of analysis showed that the higher non regular employment rate, the lower female employment rate, and the lower economy growth rate decrease fertility rate especially in low fertility rate country. While, only the higher house rental decrease in high fertility country. This results indicate that low fertility country including Korea should improve a labor policy such as strengthening employment security and encouraging female employment to increase fertility rate.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.8
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• pp.1147-1153
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• 2000

A total of 9,540 pigs were evaluated for their growth performance to provide information on the development of different feeding strategies to support maximum rate of protein deposition (PD). Large variations in growth performance and protein deposition rate were found in the population used in this study (ADG from 701 to 974 g/day; ADFI from 1,726 to 2,498 g/day; Feed/gain from 2.10 to 2.90; Backfat thickness from 12.4 to 20.5 mm and PD rate from 103 to 153 g/day). It was found that ADG was positively correlated to PD ($R^2=0.9362$, p<0.0001) while FCR was negatively correlated to PD ($R^2=0.4031$, p<0.0001). Backfat thickness was negatively correlated to PD ($R^2=0.7024$, p<0.0001) and to ADG ($R^2=0.5096$, p<0.0001). The estimated lysine requirement based on PD rate also showed large variation (12.37 to 18.38 g/day true ileal digestible lysine on average between 25 and 100 kg), thus strongly indicated the need of separate feeding strategies for each group of pigs. When pigs were divided into three categories according to estimated whole body PD rate, the group of pigs with the highest PD rate grew faster by 6.3 and 13.9% than pigs with intermediate and low PD rate, respectively. Feed utilization was also more efficient in pigs with a high PD rate. It appeared that pigs with high PD rate maintained higher PD rate especially in the later stage of their life. Pigs with high PD rate require an extra amount of 1.2 and 2.4 g/true digestible lysine per day and 0.4 and 0.8% more lysine in the diet than pigs with intermediate and low PD rate during the growing-finishing period respectively. Results of this study suggest that there is a need for separate feeding strategies for individual group of pigs with different PD rate. It should be noted that average value for each group presented in this report is not the adequate amount for an animals potential for maximum PD rate. With recent development in growth modeling and access to computer technologies to facilitate computation, pork producers can easily estimate pigs protein deposition rate and thus can make their own feeding strategies.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.1
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• pp.11-19
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• 1999

This experiment was conducted with nine wheat geno-types to choose the wheat which has excellent early vigour. 'Vigour 18' and 'ZL 59A' are excellent in the long coleoptile genotype, while 'Amery' and 'Janz' are excellent in the short coleoptile genotype. Responding to the growth stage and nitrogen level, Vigour 18 is predominant in the long coleoptile genogype, while Janz in the short coleoptile genotype. Responding to sowing density and nitrogen level, the higher the sowing density was, the shorter the leaf area of Vigour 18 and Janz. Also the leaf area turned out to larger in the plot fertilized with high nitrogen than in the plot fertilized with low nitrogen. This is true of leaf weight and root weight. Concerning specific leaf area (SLA) and leaf area ratio (LAR), the higher the sowing density was, the SLA tended to grow larger, while the SLA grew larger in the plot fertilized with low nitrogen, as were found in Vigour 18 and Janz. The roots of long coleoptile genotype, Vigour 18, turned out to grow longest on the plot sown with 3 seeds. While the roots of short coleoptile genotype, Janz, grew longest on the plot sown with 2 seeds. The relative growth rate (RGR) was the same at low N rates and high N rates. The RGR was 0.071 and 0.072 g $g^{-1}d^{-1}$ at low N rates and high N rates. The partitioning of RGR into net assimilation rate (NAR) and LAR showed that the average LAR at low N rates was similar to the LAR at high N rates. Variation within each cultivar in the LAR and NAR was small relative to the difference between them at low N rates and high N rates. Above ground mass was 8.2 mg greater at high N rates than low N rates, whereas leaf area was 0.05 $\textrm{m}^2$$kg^{-l}$ greater at high N rates than low N rates. The NAR was similar at low N rates and high N rates, whereas LAR was greater at high N rates (0.05 $\textrm{m}^2$$kg^{-l}$); variation in SLA was responsible for the variation in NAR and LAR both at low N rates and high N rates. NAR was more closely associated with the reciprocal of SLA.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.1
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• pp.28-36
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• 1992

Fifty rice varieties were tested for alkali digestibility of milled rice grain at four different KOH levels, and twenty-four varieties selected were tested again for alkali digestibility at different degrading times and KOH levels. Gelatinization rate at several heating times and heating temperatures, and water absorption rate at 21$^{\circ}C$ and 77$^{\circ}C$ water temperatures were observed using rice samples of twenty-four varieties to clarify the relationship between alkali digestibility response, gelatinization rate and water absorption rate. Varietal difference of ADV in Japonica and Tongil tye rices was biggest at KOH 1.2%, but it was better to test at KOH 1.2% and 1.4% levels to know the exact alkali digestibility response of rice varieties. Rice varieties tested could be classified into three groups, low, intermediate and high, based on their alkali digestibility response at four KOH levels, and most of Korean cultivated rice varieties were belonged to intermediate or high ADV group. Varietal variation was also found in alkali degrading response at different soaking times in alkali solution. Low ADV varietal group showed higher gelatinization temperature and needed longer heating time for complete gelatinization compared with intermediate or high ADV group. Same trends was found between intermediate and high ADV groups, but varietal variation in the same ADV group was also found in gelatinization temperature and heating time needed for complete gelatinization of rice grain. Water absorption rate of low ADV group was lower than intermediate or high ADV group both at 21$^{\circ}C$ and 77$^{\circ}C$ water temperatures, and intermediate ADV group showed lower absorption rate than high ADV group only in initial water absorption stage at 21$^{\circ}C$.

• Analytical Science and Technology
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• v.6 no.2
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• pp.167-180
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• 1993

The effects of coating variables on the formation of aluminide coating layer with good oxidation resistance on the strongest hot-forged superalloy in the world, KM 1557 developed at KIST by pack cementation process were studied. Pack aluminizing were performed by high-activity process with pure aluminium powders and by low-activity process with codep powders. For high-activity process, Al deposition rate, growth rate of coating layer, and cross-sectional microstructures were influenced by the species and additive amounts of activators and the additive amounts of pure aluminium powders. For low-activity process, Al deposition rate, growth rate of coating layer, and the cross-sectional microstructures were not influenced by the species but additive amounts of activators. Surface structures of coating layer were influenced by the species of activators. Regardless of aluminium activity, Al deposition rate was proportional to the square root of time and parabolic rate constants were different with the species of activators. The activation energy for deposition of aluminium was different with the species of activators for high-activity process. Regardless of the species of activators, the activation energy for deposition of aluminium was 12~14 Kcal/mole for low-activity process.

• Particle and aerosol research
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• v.14 no.4
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• pp.171-180
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• 2018

To optimize the shape of the electrostatic precipitator for the removal of particulate matter in subway environments, the wind-tunnel experiments were carried out to characterize collection efficiency and ozone emission rate. As a standardized parameter, power consumption divided by the square of flow velocity, was increased, the $PM_{10}$ collection efficiency increased. If the standardized parameter is higher than 1.0 due to high power consumption or low flow velocity, increase in thickness of electrodes from 1 to 2 mm, or increase in distance of collection plates from 5 to 10 cm did not change the $PM_{10}$ collection efficiency much. Increase in thickness of high-voltage electrodes, however, can cause decrease in $PM_{10}$ collection efficiency by 28% for low power consumption and high flow velocity. The ozone emission rate decreased as distance of collection plates became wider, because the ozone emission rate per unit channel was constant, and the number of collection channels decreased as the distance of collection plates increased. When the distance of collection plates was narrow, the ozone emission rate increased with the increase of the thickness of electrodes, but the difference was negligible when the distance of collection plates was wide. It was found that the electrostatic precipitator having a thin high-voltage electrodes and a narrow distance of collection plates is advantageous. However, to increase the thickness of high-voltage electrodes, or to increase the distance of collection plates is needed, it is necessary to increase the applied voltage or reduce the flow rate to compensate reduction of the collection efficiency.