• Journal of Powder Materials
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• v.16 no.5
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• pp.363-369
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• 2009

The amorphization process and the thermal properties of amorphous Ti$_{40}$Cu$_{40}$Ni$_{10}$Al$_{10}$ powder during milling by mechanical alloying were examined by X-ray diffractometry (XRD), differential scanning calorimetry (DSC), and transmission electron microscopy (TEM). The chemical composition of the samples was examined by an energy dispersive X-ray spectrometry (EDX) facility attached to the scanning electron microscope (SEM). The as-milled powders showed a broad peak (2$\theta$ = 42.4$^{\circ}$) with crystalline size of about 5.0 nm in the XRD patterns. The entire milling process could be divided into three different stages: agglomeration (0 < t$_m$ $\leq$ 3 h), disintegration (3 h < t$_m$ $\leq$ 20 h), and homogenization (20 h < t$_m$ $\leq$ 40 h) (t$_m$: milling time). In the DSC experiment, the peak temperature T$_p$ and crystallization temperature T$_x$ were 466.9$^{\circ}C$ and 444.3$^{\circ}C$, respectively, and the values of T$_p$, and T$_x$ increased with a heating rate (HR). The activation energies of crystallization for the as-milled powder was 291.5 kJ/mol for T$_p$.

• Journal of IKEEE
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• v.2 no.2 s.3
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• pp.233-238
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• 1998

In this paper, the implementation of dual rate ADPCM using G.726 16Kbps and 40Kbps speech codec algorithm is handled. For small signals, the low rate 16Kbps coding algorithm shows almost the same SNR as the high rate 40Kbps coding algorithm , while the high rate 40Kbps coding algorithm shows the higher SNR than the low rate 16Kbps coding algorithm fur large signal. To obtain the good trade-off between the data rate and synthesized speech quality, we applied low rate 16Kbps for the small signal and high rate 40Kbps for the large signal. Various threshold values determining the rate are applied for good trade-off between data rate and speech quality. The simulation result shows the good speech quality at a low rate comparing with 16Kbps & 40Kbps.

• Korean journal of food and cookery science
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• v.20 no.6 s.84
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• pp.630-636
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• 2004

The effects of soaking and steaming time on the quality characteristics of Korean rice cake (karedduk) were investigated. As the soaking time increased, the water-binding capacity and rice floor solid content also increased. After 8 to 10 hr soaking, 75.2 to $76.8\%$ of particles were smaller than $40\;{\mu}m$, and 23.2 to $24.8\%$ within the range of 40 to $100\;{\mu}m$. Therefore, an extended soaking time reduced the particle size. Texture is an important characteristic used to differentiate karedduk varieties, and is considered by the consumer as a determinant of the overall quality and preference. The hardness, cohesiveness, gumminess and chewiness of the karedduk structure decreased with increasing steaming time, but the springiness was highest after a 40 min steaming time. The overall texture properties were also more acceptable with 8 and 10 hrs soaking times. The L value of the karedduk decreased with increasing steaming time, but the b value increased. Also, the results of the sensory evaluation showed that an 8 hr soaking time and 40 min steaming time produced more acceptable karedduk in terms of whiteness, texture, springiness, chewiness and overall acceptability.

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.1
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• pp.29-38
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• 2007

Recently, the tropospheric ozone has gained a global attention for its adverse effect on vegetation as well as its contribution to the global warming. Although a number of studies have been carried out for the urban ozone, the effect of ozone on vegetation is still largely unknown in Korea. The present work aimed at performing the first evaluation of forest damage by ozone using the national air monitoring data from the year 2000 to the year 2005. Moreover, it also explored the relevance of adverse effect of ozone to the recent events on leaf chlorosis of black locust, Robinia pseudo-acacia, leading to early foliage widely observed in Korea since 2001. In the nineties, forest damages caused by ozone such as leaf chlorosis occurred in Europe and North America and led to invoke comprehensive field and laboratory studies. As a result, AOT40, implying the accumulated dose over a threshold 40 ppb, was developed to assess the forest damage by ozone. 19 air monitoring stations were selected across Korea to calculate AOT40 from the year 2000 to the year 2005. The calculated AOT40 generally increased during April and May and reached the maximum after May. The increase of AOT40 diminished substantially from the mid-June as the rainy season started. The calculated AOT40 in the nine rural sites from the year 2002 to th ε year 2005 ranged from 6.8 to 29.4 ppm-hr. And all the AOT40 at th ε year 2005 exceeded the critical value of 10 ppm-hr for forest damage. Morevoer the calculated AOT40 of Korea appeared higher than the AOT40 of Europe in the year 2004/2005 and comparable to the AOT40 of China in the year 2000. Despite the high levels of the calculated AOT40 since the year 2001 and the consistency of time of seasons between high AOT40 values and occurrence of chlorosis of black locust, further studies are required to conclude that the chlorosis of black locust occurred from the year 2001 to the year 2005 were resulted from a damage by ozone.

• Preventive Nutrition and Food Science
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• v.16 no.1
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• pp.83-88
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• 2011

The wholesomeness of 40 kGy irradiated ready-to-eat (RTE) bulgogi was evaluated by subacute toxicity studies (body weight, food consumption, organ weight, hematology, serum biochemistry, and histopathological examination) with groups of 40 male and female ICR mice fed the agent at dietary levels of 5% for 90 days. There were no treatment-related adverse effects with regard to body weight, food consumption, organ weight, hematology, serum biochemistry, and histopathology. The no-observed-adverse-effect-level (NOAEL) was also determined to be greater than dietary level of at least 5% (3900 mg/kg body weight/day for males, 3500 mg/kg body weight/ day for females) for samples under the present experimental conditions. These results suggest that, under these experimental conditions, RTE bulgogi irradiated at 40 kGy did not show any toxic effects.

• Korean Journal of Soil Science and Fertilizer
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• v.4 no.1
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• pp.33-40
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• 1971

Using radioactive $^{40}K$ in potassium, a study was conducted to evaluate the potassium supplying power of different soil types developed on different parent materials. A conversion factor based on two parameters namely $\frac{available\;K_{soil}}{total\;K_{soil}}$ and $\frac{K_{plant}}{K_{soil}}$ was developed and found to be closely related to plant response. According to this characterization soils derived from the various parent materials were ranked as basalt >Silla series>gneiss>porphyry>granite${\gg}$schist. From the point of view of potassium response as measured by yield as similar response pattern was observed. That is, soils derived from basalt to be most responsive as compared to the other soils. The variations among the soils may be accounted for to their potassium bearing mineralogical composition and their stability.

• Proceedings of the Materials Research Society of Korea Conference
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• 2008.11a
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• pp.40.2-40.2
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• 2008

• Proceedings of the Korean Magnetic Resonance Society Conference
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• 2000.08a
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• pp.40-40
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• 2000

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.07a
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• pp.40-40
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• 2004

• Proceedings of the Korean Magnestics Society Conference
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• 2010.06a
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• pp.102-103
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• 2010