• Journal of Powder Materials
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• v.28 no.5
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• pp.423-428
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• 2021

Here, we report the development of a new and low-cost core-shell structure for lithium-ion battery anodes using silicon waste sludge and the Ti-ion complex. X-ray diffraction (XRD) confirmed the raw waste silicon sludge powder to be pure silicon without other metal impurities and the particle size distribution is measured to be from 200 nm to 3 ㎛ by dynamic light scattering (DLS). As a result of pulverization by a planetary mill, the size of the single crystal according to the Scherrer formula is calculated to be 12.1 nm, but the average particle size of the agglomerate is measured to be 123.6 nm. A Si/TiO₂ core-shell structure is formed using simple Ti complex ions, and the ratio of TiO₂ peaks increased with an increase in the amount of Ti ions. Transmission electron microscopy (TEM) observations revealed that TiO₂ coating on Si nanoparticles results in a Si-TiO₂ core-shell structure. This result is expected to improve the stability and cycle of lithium-ion batteries as anodes.

• Korean Journal of Community Nutrition
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• v.10 no.1
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• pp.101-110
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• 2005

This survey was carried out to obtain the information concerning nutritional status, including factors of food habits and nutrient intake of the long-lived elderly men and women living in Ganghwa-gun. In order to assess the quality of dietary intake among the elderly, a survey was conducted during December 2003 of 103 subjects who were over 85 years of age. Dietary nutrient intake data were obtained through the 24 hr recall method. Chi-square test and t-test were the main data analysis method. Their dietary habits such as three meals a day and a regular meal time have shown that they have generally good eating habits. Average daily calorie intake ($\%$ RDA) was 1233.2 kcal ($68.8\%$) for male and 1215.8 kcal ($75.8\%$) for female which were lower than the Recommended Dietary Allowances (RDA) for Koreans. Energy intake of females got closer to RDA than that of male. Protein intake was 49.3 g for male and 46.9 g for female (which was $82.3\%$ RDA for male and $85.1\%$ RDA for female) for elderly person, the proportion of animal protein to total protein intake were $45.2\%$ for male and $39.0\%$ for female. Average CPF ratio of energy intake for both male and female were 68.7 : 16.1 : 15.2 and 69.6 : 15.4 : 15.0. SFA : MUFA : PUFA ratio of the subject was 0.78 : 1.03 : 1.00 for male and 0.64 : 0.92 : 1.00 for female. Calcium intakes for both males and females were 321.3 mg and 377.2 mg. Vitamin A was the nutrient found to be least sufficient. Mean daily intakes of most of the vitamins and minerals for both males and females were lower than RDA except vitamin C and Zn for female, especially $\%$ RDAs of vitamin A, Ca for male and vitamin A for females were less than $50\%$ of RDA. In conclusion, long-lived elderly in Ganghwa areas did not consume enough nutrients quantitatively as well as qualitatively, especially Ca, Fe, vitamin A, vitamin $B_2$ and vitamin E. These results suggest that nutritional guidelines for older Koreans should focus on the maintenance of adequate energy intake. In addition, selection of foods with high protein and calcium, such as dairy food, should be emphasized, particularly in the long-lived elderly.

• Resources Recycling
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• v.23 no.5
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• pp.55-61
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• 2014

Froth flotation was performed to study the effect of phosphate addition in the experiment to remove As from tailing of Sang-dong Mine. The experiment without Trisodium phosphate (T.S.P) showed that the removal rate of As was 88.7% and weight-ratio of floating material was 2.52%. By contrast, the experiment with T.S.P showed that the removal rate of As was 92.74% and weight-ratio of floating material was 2.26%. In flotation without T.S.P, the average particle size of float material was 19.34 um and the amount less than 10um was 40.2%. On the other hand, in flotation with T.S.P the average particle size of float material was 176.8 um and the amount less than 10um was 6.5%. The result of X.R.F analysis presented that contents of $SiO_2$ was 42.74% in float material of the experiment without T.S.P. In contrast, contents of $SiO_2$ was 29.56% in float material of the experiment with T.S.P.

• Korean Journal of Community Nutrition
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• v.5 no.2
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• pp.297-306
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• 2000

In order to examine the relationship between the number of different foods consumed and nutrient intake, one-day food consumption were surveyed by 24-hour recall from a sample of 287 individuals(20-49 years) living in Daejon City. The number of consumed food items did not include seasonings except red pepper power, sugar, oil, and soybean paste when used in large amounts(DVS). The number, including all seasonings except salt and vinegar(DVSS), was also counted. Of the total subjects, 43.6%(DVS) or 39.0%(DVSS) consumed 18-23 daily different foods with an average of 20.2 or 22.9, respectively. As the DVS increased, daily intakes of total foods and most food groups were elevated. Cereals however were not changed and eggs were decreased with increasing DVS. Energy and nutrient intakes and their mean adequacy ratio(MAR) and index of nutritional quality(INQ) also show positive correlations with DVS. MAR equal to or greater than($\geq$) 0.75 was taken as a cut-off point for nutritional adequacy. In that case, the mean INQ was shown to be $\geq$1. MRI(10) for energy and 9 nutrients and MAR(3) for Ca, vitamin A, and riboflavin were estimated. Form a regression analysis, when MAR(10) was 0.75, the DVS and DVSS were assumed to be 19.6 and 22.2, respectively. And when MAR(3) was 0.75, the DVS and DVSS were assumed to be 31.6 and 34.6, respectively. However the subjects whose MAR(3) was 0.75(0.7-0.8) 23.8(DVS) or 26.6(DVSS) different foods in average, and their mean intakes of energy and all nutrients, except vitamin A, were ranged at 85-100% of the RDA. Of the 74 subjects who consumed DVS$\geq$24, 24 to 42 numbers took 〈75% RDA of Fe, Ca, riboflavin, and vitamin A. And five of 7 who consumed DVS$\geq$32 took $\geq$125%RDA of protein, which showed concerns of overnutrition in case of DVS$\geq$32. Form the above results it could be suggested that a daily intake of 24-32(or 28) of DVS or 27-35(or 31) of DVSS was recommendable for an optimal nutritional of all nutrients if the variety of food groups and sufficient intake of vitamin A and calcium were emphasized together.

• Journal of Convergence for Information Technology
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• v.11 no.6
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• pp.1-6
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• 2021

In the field of speech recognition, as the DNN is applied, the use of speech recognition is increasing, but the amount of calculation for parallel training needs to be larger than that of the conventional GMM, and if the amount of data is small, overfitting occurs. To solve this problem, we propose an efficient method for robust voice feature extraction and voice signal noise removal even when the amount of data is small. Speech feature extraction efficiently extracts speech energy by applying the difference in frame energy for speech and the zero-crossing ratio and level-crossing ratio that are affected by the speech signal. In addition, in order to remove noise, the noise of the speech signal is removed by removing the noise of the speech signal with an average predictive improved LMS filter with little loss of speech information while maintaining the intrinsic characteristics of speech in detection of the speech signal. The improved LMS filter uses a method of processing noise on the input speech signal by adjusting the active parameter threshold for the input signal. As a result of comparing the method proposed in this paper with the conventional frame energy method, it was confirmed that the error rate at the start point of speech is 7% and the error rate at the end point is improved by 11%.

• Korean Chemical Engineering Research
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• v.57 no.6
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• pp.874-882
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• 2019

In this study, the gasification characteristics of four types of unused woody biomass and one waste wood in a lab-scale bubbling fluidized bed gasifier (Diameter: 0.11 m, Height: 0.42 m) were investigated. Effect of equivalence ratio (ER) of 0.15-0.3 and gas velocity of $2.5-5U_0/U_{mf}$ are determined at the constant temperature of $800^{\circ}C$ and fuel feeding rate of 1 kg/h. The silica sand particle having an average particle size of $287{\mu}m$ and olivine with an average particle size of $500{\mu}m$ were used as the bed material, respectively. The average product gas composition of samples is as follows; $H_2$ 3-4 vol.%, CO 15-16 vol.%, $CH_4$ 4 vol.% and $CO_2$ 18-19 vol.% with a lower heating value (LHV) of $1193-1301kcal/Nm^3$ and higher heating value (HHV) of $1262-1377kcal/Nm^3$. In addition, it was found that olivine reduced most of C2 components and increased $H_2$ content compared to silica sand, resulting in cracking reaction of tar. The non-condensable tar decreases by 72% ($1.24{\rightarrow}0.35g/Nm^3$) and the condensable tar decreases by 27% ($4.4{\rightarrow}3.2g/Nm^3$).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.4
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• pp.366-371
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• 2011

The sea squirt Halocynthia roretzi is mainly cultured in Tongyeong, Southern coastal area of Korea. This study presents the physiological rates of respiration, excretion, feeding and assimilation efficiency of the sea squirt Halocynthia roretzi to analyze the SFG(scope for growth) and net growth efficiency, determined during 2007. Oxygen consumption and nitrogen excretion rates increased with a rise in temperature during the summer period whereas feeding rates decreased. The O:N ratio was high during winter(October to February). Assimilation efficiency showed an annual average of 75.4% during the experimental period, except during a period of elevated temperature in July to September(average $25^{\circ}C$). Net growth efficiency($K_2$) was 8.7 to 64.2% except for May to September, when temperature increased at the aquaculture farm. SFG was negative from May to September, reflecting high temperatures and low feeding rates during this period; its highest positive values occurred during winter.

• Nutrition Research and Practice
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• v.6 no.1
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• pp.86-90
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• 2012

This study assessed the association between vitamin D sufficiency (serum 25(OH)D ${\geq}30ng/mL$) and alcohol consumption using data from the Korea National Health and Nutrition Examination Survey conducted in 2009. The following characteristics were obtained in 7,010 Korean participants ${\geq}19$-years-of-age: serum 25(OH)D level, alcohol consumption (drinking frequency, drinking number of alcoholic beverages on a typical occasion, average daily-alcohol intake), and potential confounders (age, residence, housing status, occupation, total fat and lean mass, smoking, physical activity, history of liver diseases, liver function, and daily intake of energy, protein, and calcium). After adjusting for confounders, vitamin D sufficiency in men was significantly associated with drinking frequency, number of alcoholic drinks consumed, and average daily alcohol intake; odds ratio of 1.21-1.72, 2.17-3.04, and 2.27-3.09, respectively. Increase in the three alcohol drinking-related behaviors was also linearly associated with increase in serum 25(OH)D level in men. By comparison, there was no significant association between alcohol intake and serum 25(OH)D level in women. The positive association between vitamin D sufficiency and alcohol consumption was evident only in Korean men.

• Korean Journal of Food Science and Technology
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• v.15 no.3
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• pp.220-224
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• 1983

The hydration of water, at $20^{\circ}\;30^{\circ}$ and $40^{\circ}C$ for 10-360 minutes, by the two varieties of husked barley and of naked barley which were polished to 40 and 30%, respectively, was investigated. The absorption was directly proportional to the square root of the hydration time and accounted for by the diffusion equation: 1-M = $(2/{\sqrt\pi})\;(S/V){\sqrt{Dt}}$, where 1-M is the relative moisture gain and S/V is the surface-to-volume ratio. The average diffusion coefficient (D) was given by the Arrhenius relation: D = $D_{0}\;exp\;(-Ea/RT)$, where the activation energy for both husked and naked barley was about 7.2 Kcal/mole. The average value of D for naked barley was slightly higher than that for husked barley.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.11
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• pp.776-781
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• 2007

Optimized capacity of equipments are essential for energy saving and low cost construction and operation. So we must use proper design data for HVAC system design. We investigated for architectural data, equipment capacity, cooling and heating load design criteria of 52 office buildings. Following research results were obtained by carrying out each task. Office building effective area rate is 63%. The average building cooling load of South Korea is $140W/m^2$ and average heating loads in Seoul and Pusan area are $120{\sim}130W/m^2$ and $70{\sim}80W/m^2$. We also analysised HVAC design criteria. Person ratio in effective building area is $0.2person/m^2$, sensitive and latent heat loads of a person are 60W and 65W, light and equipment loads of office buildings are $25W/m^2$ and $20W/m^2$.