• 대한치과교정학회지
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• 제52권3호
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• pp.201-209
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• 2022

Objective: To compare the removal torque of microimplants upon post-use removal and post-retention removal and to assess the influencing factors. Methods: The sample group included 241 patients (age, 30.25 ± 12.2 years) with 568 microimplants. They were divided into the post-use (microimplants removed immediately after use or treatment) and post-retention (microimplants removed during the retention period) removal groups. The removal torque in both groups was assessed according to sex, age, placement site and method, and microimplant size. Pearson correlation and multiple linear regression analyses were performed for evaluating variables influencing the removal torque. Results: The mean period of total in-bone stay of microimplants in the post-retention removal group (1,237 days) was approximately two times longer than that in the post-use removal group (656.28 days). The removal torques in the post-retention removal group (range, 4-5 N cm) were also higher than those in the post-use removal group. The mandible and pre-drilling groups demonstrated higher placement and removal torques than did the maxilla and no-drilling groups, respectively. In the no-drilling post-use removal group, the placement torque and microimplant length positively correlated with the removal torque. In the post-retention removal group, unloading in-bone stay period and microimplant diameter positively correlated with the removal torque in the no-drilling and pre-drilling methods, respectively. Conclusions: The removal torques differed according to the orthodontic loading and removal time of microimplants. With prolonged retention of microimplants inserted using the no-drilling method, the removal torque was clinically acceptable and positively correlated with the unloading in-bone stay period.

• 디지털융복합연구
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• 제19권11호
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• pp.113-119
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• 2021

본 연구는 코로나19 팬데믹의 영향으로 매출이 상승한 정보통신업 기업을 대상으로 팬데믹 선언 전·후의 경영성과와 이익의 질을 비교하고 이러한 차이가 유의미한지를 분석하였다. 이를 위하여 경영성과는 수익성, 성장성, 유동성, 안정성의 4가지 지표를 사용하고, 이익의 질은 Dechow and Dichev(2002) 모형과 Francis et al.(2005)의 모형을 이용하여 측정한 잔차의 표준편차를 이용하였다. 분석 결과, 대표적인 경영성과 지표인 ROA는 팬데믹 이전 기간보다 이후 기간이 상승하였지만, 유동성은 오히려 악화된 것으로 나타났다. 이익의 질 또한 ROA와 마찬가지로 팬데믹 이후 기간이 이전 기간에 비하여 이익 지속성이 유지되고 있음을 확인하였다. 전반적으로 정보통신업 기업의 이익 수준과 이익의 질은 개선되고 있는 것으로 보이지만 유동성은 약화하고 있으므로 눈앞의 위기를 넘겼던 기업들이 당장 부채를 상환할 준비는 되어있지 않다는 것을 확인하였다. 따라서 앞으로 코로나19가 진정되는 시점부터 늘어난 부채를 줄이기 위한 기업들의 구조조정이 필요함을 시사한다.

• 한국초지조사료학회지
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• 제17권2호
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• pp.187-198
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• 1997

This experiment was conducted to evaluate effects of wilting and additives on fermetation characteristics, quality and aerobic stability of silage of rye(Seca1e cereale L.) harvested at the early heading stage. Harvested rye was wilted or mixed with beet pulp and then treated with formic acid or lactic acid bacteria(LAB) inoculant. Treatments were consisted of direct cut(DC), wilted(WT), beet pulp added(BP), direct cut and formate applied(DF), wilted and formate applied(WF), beet pulp and formate applied(BF), direct cut and LAB inoculated(DL), beet pulp added and LAB inoculated(BL), and wilted and LAB inoculated(WL) silages. Afler 70 days of ensiling period, the silages were opened and exposed to air for 7 days, and the silages of opening day(0 day) were compared with the silages exposed to air for 7 days(7 day). 1. LAB inoculated rye silages(DL, WL, BL) lowered pH values effectively eom the third day of ensiling and showed most stable pattern of pH changes during the initial fermentation process. Direct cut and formate applied(DF), beet pulp and formate applied(BF) and beet pulp added(BP) silages were also effective in lowering pH from the seventh day thai direct cut treatment(DC). 2. pH was low below 3.7 in all treatments of 0 day. After 7-day period of aerobic exposure, DL and WL showed considerable increases in pH from 3.5 and 3.4 to 8.3 and 6.4, respectively. 3. Direct cut rye silages(DF, DC, DL) and beet pulp and formate treatment(BF) produced effluent of 121.2, 85.9, 80.3 and 34.2 mlkg, respectively and these were greater than others(P<0.01). Beet pulp retained 1.61 I/kg of effluent at the application rate of 50 kg/t in comparing BP with DC, and formate application increased the amount of effluent in comparing DF and BF with DC and BP, respectively(P<0.01). 4. Beet pulp and LAB treatment(B1) was highest in content of lactate as 3.1% and formate treated silages(DF, WF, BF) showed lower content of lactate and total acid than others. LAB inoculated(D1, WL, BL) and wilted (WT) silages were graded to be good quality as a second group by the Flieg's score. Formate applied silages (DF, WF, BF) were graded as a foum group lower than DC by one. 5. Residual content of WSC of rye silage was higher in BP, BF, DL and BL than direct cut treatment(M3) (P< 0.01). Formate application had a tendency to increase the content of residual content of WSC. 6. For the ratio of NH3-N to Total N, wilted and LAB inoculated(W1) and direct cut and LAB inoculated(D1) silages were lowest on 0 day as 8.9 and 9.3% respectively. But after 7-day period of aerobic exposure, WL and DL showed largest increase of the ratio of $NH_3-N$ to Total N from 0 day(P<0.01). 7. On 0 day wilted(WT), beet pulp and formate treatment(BF), and beet pulp and LAB treatment(B1) were lower than direct cut treatment(DC) for NDF and ADF concentrations consistently. Formate applied silages (DF, WF, BF) made little change in ADF and NDF concentrations during 7 day period of aerobic exposure. DL and WL showed a large increase in ADF and NDF concentrations under aerobic condition(P<0.01). 8. IVDMD values of wilted(WT), beet pulp added(BP), wilted and LAB inoculated(W1) and beet pulp added and LAB inoculated(B1) silages were higher than direct-cut treatmentPC) as 84.7, 84.7, 84.4 and 83.0%, respectively on 0 day. But during 7-day period of aerobic exposure, a great decreae in IVDMD of WL was showed(P<0.01). The experimental results indicate that wilted silage(WT) could be recommended as the most effective treatment for reducing efluent and increasing quality and feed value of rye silage without deteriorating aerobic stability more than direct cut treatment(DC). Additionally, under unfavorable weather condition beet pulp added and LAB inoculated treatment(T3L) might be the possible alternative for successful ensiling of forage rye.

• Korean Chemical Engineering Research
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• 제53권5호
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• pp.609-613
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• 2015

The onset of instability induced by impulsive spin-down of the rigid-body flow placed in the gap between two coaxial cylinders is analyzed by using the energy method. In the present stability analysis the growth rate of the kinetic energy of the base state and also that of disturbances are taken into consideration. In the present system the primary flow is a transient, laminar one. But for the Reynolds number equal or larger than a certain one, i.e. $Re{\geq}Re_G$ secondary motion sets in, starting at a certain time. For $Re{\geq}Re_G$ the dimensionless critical time to mark the onset of vortex instabilities, ${\tau}_c$, is here presented as a function of the Reynolds number Re and the radius ratio ${\eta}$. For the wide gap case of small ${\eta}$, the transient instability is possible in the range of $Re_G{\leq}Re{\leq}Re_S$. It is found that the predicted ${\tau}_c$-value is much smaller than experimental detection time of first observable secondary motion. It seems evident that small disturbances initiated at ${\tau}_c$ require some growth period until they are detected experimentally.

• The Journal of Asian Finance, Economics and Business
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• 제7권6호
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• pp.173-183
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• 2020

The paper investigates the determinants of foreign direct investment (FDI) in Vietnam in 2000-2019 period. This study uses difference Generalized Methods of Moments (GMM) and Pooled Mean Group (PMG) to analyse panel data officially provided by General Statistical Office of Vietnam. The results show that market size impacts positively significant on FDI attraction: 1% -1.45% (PMG) and 1% -1.25% (GMM). Besides, some other factors have positive influences as labor force, macroeconomic policy, macroeconomic stability and skilled labor. Meantime, the trade openness negatively affects FDI inflows in the short-term, while not being statistically significant in the long-term. Moreover, economic shocks often have a negative impact on FDI inflows. The findings of this study lead to the following recommendations. First, authorities should pay special attention to encourage economic growth rate in Vietnam to expand market size because this is the first priority of foreign investors. Second, authorities need to continue increasing the rate of skilled labor, especially highly qualified management force, engineers and well-skilled workers. Third, the authorities should adjust trade openness to boost the role of its determinant in attracting FDI inflows. Fourth, macroeconomic stability needs to be governed by international standards in order to secure the belief of foreign investors in the long-term.

• The Journal of Asian Finance, Economics and Business
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• 제7권6호
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• pp.9-18
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• 2020

This study seeks to analyze the effect of Non-Performing Loans and Capital Adequacy Ratio on Return on Assets on ten conventional banks listed on the Indonesia Stock Exchange (BEI-IDX). This study uses secondary panel data for 2015-2019 in the form of CAR and NPL values from ten conventional banks listed on the BEI-IDX during the 2020 observation period. The research approach is quantitative descriptive with data analysis methods, namely, linear regression. The testing phase of this study includes: transform value, F-test, T-test and hypothesis test with significancy level sig < 0.05. The results of this study reveal that Non-Performing Loans had a significant negative effect (t = -2,637) (0.011 <0.0) on Return on Assets, while Capital Adequacy Ratio has no significant effect on ROA (0.760 > 0.05). R2 value is 0.128 or 12.8%. It has a significant effect on variables, calling efforts by banks, governments, and authorities monetary of related institutions to maintain the stability of finance. The reduction of Non-Performing Loan impacts on assets and capital adequacy ratio, besides, the normal NPL will control the stability of finance. If a balance is created either in the form of values or amounts of the variables, the reduction in Non-Performing Loans will be controlled.

• 가정과삶의질연구
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• 제19권4호
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• pp.211-223
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• 2001

This study analyzed the financial ratio change of self-employed households between 1997 and 1998. The data were drawn from Korean Households Panel Study and utilitze7 descriptive statistics such as frequency, percentile to investigate the differences between two period of time, 1997 and 1998. The sampe size in 1997 was 692 householdsand and 600 households in 1998. The mean of financial asset showed that in 1997, self-employed households had much less in liquidity assets, especially in bank-related income, stock, but had more in real-estate, Gye, and private loan than those in 1998. In cases of debt-owned, the self-employed tended to have more debt in non-bank related and it illustrates that the self-employed may experience the difficulties to access the financial assistance in economic depression. Using guideline of each ratios, for six financial ratios, self-employed could meet less proper level$ in 1998 compared to those in 1997. It proves that the economic crisis affect the stability of income and financial assets of self-employed households and types of financial assets changes because of the stability.

• Journal of Nutrition and Health
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• 제18권1호
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• pp.36-45
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• 1985

The effects of glucose, lactose, sucrose, and potato starch on kimchi fermentation and on the stability of ascorbic acid were investigated at $7^{\circ}C$. Kimchi samples with the sugars showed the higher PH and lower total acidity until 9th day of fermentation than kimchi without sugar. Changes in the pH and total acidity were not significantly different among the samples after the 12th day. Addition of the sugars did not show any effects on the growth of lactobacilli through the fermentation period. The amounts and changes in ascorbic acid content during the fermentation did not differ significantly between the control and sugar - added samples. Ascorbic acid in most samples decreased continuously by the 9th day of fermentation. After then the vitamin increased in all the samples and then again decreased slowly after 18th day. From the multiple comparison tests the 10- panel members indicated the better flavor of sugar - added samples than control sample. However the differences in flavor were not significant.

• 한국식품영양학회지
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• 제13권5호
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• pp.403-410
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• 2000

본 연구에서는 전분을 냉동반죽에 첨가한 효과에 대해 알아보았다. 냉동생지의 물리적 특성은 farino-graph. extensograph, amylograph를 통해 측정되었다. 측정된 결과는 전분이 첨가된 냉동반죽이 대조구에 비해 더욱 안정함을 알 수 있었다. 반죽의 물리적, 화학적 특성은 냉동보관기간에 따라서 측정되었는데 전분을 첨가한 반죽이 대조구에 비해 물리적, 화학적 변화가 작음을 보여주었다. 이는 전분이 냉동반죽의 냉동보관중 제품열화를 방지함을 의미한다. 이로부터 전분은 냉동보관중 냉동반죽의 효모활성력과 글루텐 망상구조를 냉동장애로부터 보호한다고 생각된다. 이 실험을 통하여 여러 전분 중에 특히 감자전분의 첨가가 냉동반죽의 안정성을 향상시키는데 효과가 있음을 알 수 있었다.

• Journal of Power Electronics
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• 제14권2호
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• pp.392-401
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• 2014

A fast-transient repetitive control strategy for a three-phase shunt active power filter is presented in this study to improve dynamic performance without sacrificing steady-state accuracy. The proposed approach requires one-sixth of the fundamental period required by conventional repetitive control methods as the repetitive control time delay in the synchronous reference frames. Therefore, the proposed method allows the system to achieve a fast dynamic response, and the program occupies minimal storage space. A proportional-integral regulator is also added to the current control loop to eliminate arbitrary-order harmonics and ensure system stability under severe harmonic distortion conditions. The design process of the corrector in the fast-transient repetitive controller is also presented in detail. The LCL filter resonance problem is avoided by the appropriately designed corrector, which increases the margin of system stability and maintains the original compensation current tracking accuracy. Finally, experimental results are presented to verify the feasibility of the proposed strategy.