• Water Engineering Research
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• 제5권2호
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• pp.55-68
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• 2004

The GLEAMS (Groundwater Loading Effects of Agricultural Management System, version 3.0) water quality model was used to predict hydrology and water quality and to evaluate the effects of soil types from a cattle-grazed pasture field of Bermuda-Rye grass rotation with poultry litter application as a fertilizer in North Alabama. The model was applied and evaluated by using four years (1999-2002) of field-measured data to compare the simulated results for the 2.71- ha Summerford watershed. $R^2$ values between observed and simulated runoff, sediment yields, TN, and TP were 0.91, 0.86, 0.95, and 0.69, respectively. EI (Efficiency Index) of these parameters were 0.86, 0.67, 0.70, and 0.48, respectively. The statistical parameters indicated that GLEAMS provided a reasonable estimation of the runoff, sediment yield, and nutrient losses at the studied watershed. The soil infiltration rates were compared with the rainfall events. Only high intensity rainfall events generated runoff from the watershed. The measured and predicted infiltration rates were higher during dry soil conditions than wet soil conditions. The ratio of runoff to precipitation was ranging from 2.2% to 8.8% with average of 4.3%. This shows that the project site had high infiltration and evapotranspiration which generated the low runoff. The ratio of runoff to precipitation according to soil types by the GLEAMS model appeared that Sa (Sequatchie fine sandy loam) soil type was higher and Wc (Waynesboro fine sandy loam, severely eroded rolling phase) soil type relatively lower than the weighted average of the soil types in the watershed. The model under-predicted runoff, sediment yields, TN, and TP in Wb (Waynesboro fine sandy loam, eroded undulating phase) and Wc soil types. General tendency of the predicted data was similar for all soil types. The model predicted the highest runoff in Sa soil type by 105% of the weighted average and the lowest runoff in Wc soil type by 87% of the weighted average

• 대한치과기공학회지
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• 제40권3호
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• pp.125-131
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• 2018

Purpose: Automatic dental prosthesis manufacturing process was accelerated by the spread of dental CAD / CAM system. The CAD / CAM system with milling alloys were needed supplement. So, sintered alloy blocks were introduced. In this study, we want to study sintered alloy block. And to evaluate the alloy block manufacture and alloy properties. Methods: The alloy powders were prepared by high pressure water dispersion method. The sintered alloy blocks were prepared by low temperature pressing method. Their components observation were EDX, and the alloy structure was observed by XRD. Results: Co-Cr alloy powders were observed to have a circle shape with an average diameter of about $100{\mu}m$ and a Ni-Cr alloy powder had a circle shape with an average diameter of about $50{\mu}m$. The Co-Cr alloy block is composed of Co (34.62 wt%), Cr (17.33 wt%), Mo (2.98 wt%), Si (0.36 wt%) and C (44.17 wt%). The Ni-Cr alloy powder was composed of Ni (40.29 wt%), Cr (19.37 wt%), Mo (3.53 wt%), Si (0.52 wt%) and C (33.18 wt%). The peak of the Co and CoCr peaks were observed in the CoCr alloy body by the means of XRD study. Cr2Ni3 of the peak was observed in the Ni-Cr alloy material. Conclusion : As a result, the following conclusions were obtained. 1. Prepared by high-pressure water-law Co-Cr alloy powder has an average diameter $100{\mu}m$, Ni-Cr alloy powder was found to have the form of sphere having an average diameter $50{\mu}m$. 2. Co-Cr alloy and Ni-Cr alloy block produced by low-temperature processing showed a certain ratio. 3. In the XRD study, Co phase appeared in Co-Cr alloy block after sintering. and Cr2Ni3 phase appeared in Ni-Cr alloy block after sintering.

• 한국운동역학회지
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• 제22권4호
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• pp.429-435
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• 2012

The purpose of this study was to determine the biomechanical effect of wearing carbon nanotube-based insole on cushioning and muscle tuning during drop landing. Twenty male university students(age: $21.2{\pm}1.5yrs$, height: $175.4{\pm}4.7cm$, weight: $70.2{\pm}5.8kg$) who have no musculoskeletal disorder were recruited as the subjects. Average axial strain, average shear strain, inversion angle, linear velocity, angular velocity, vertical GRF and loading rate were determined for each trial. For each dependent variable, a one-way analysis of variance(ANOVA) with repeated measures was performed to test if significant difference existed among different three conditions(p<.05). The results showed that Average axial strain of line 4 was significantly less in CNT compared with EVA and PU during IP phase. The average shear strain was less in CNT compared with EVA and PU during other phases. The inversion angle was increased in CNT compared with EVA and PU during all phase. In linear velocity, angular velocity, vertical GRF and loading rate, there were no significant difference between the three groups. This result seems that fine particle of carbon nanotube couldn't make geometric form which can absolve impact force by increasing density through eliminating voids of forms. Thus, searching for methods that keep voids of forms may play a pivotal role in developing of insole. This has led to suggestions of the need for further biomechanical analysis to these factors.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제17권1호
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• pp.41-46
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• 2014

Purpose: The spontaneous seroconversion rate of hepatitis B e antigen (HBeAg)-positive chronic hepatitis B (CHB) virus infection in children is lower than that in adults. However, few studies have investigated the rate of transition from the immune-tolerant to the early immune-clearance phase in children. Methods: From February 2000 to August 2011, we enrolled 133 children aged <18 years who had visited the Department of Pediatrics, Kyungpook National University Hospital. All subjects were in the immune-tolerant phase of HBeAg-positive CHB virus infection. The estimated transition rate into the early immune-clearance phase was calculated using the Kaplan-Meier method. Results: Among the 133 enrolled pediatric CHB virus infection patients in the HBeAg-positive immune-tolerant phase, only 21 children (15.8%) had converted to the early immune-clearance phase. The average age at entry into active hepatitis was $10.6{\pm}4.8$ years. The incidence of transition from the immune-tolerant to the early immune-clearance phase in these children was 1.7 episodes/100 patient-years. When analyzed by age, the estimated transition rate was 4.6%, 7.1%, and 28.0% for patients aged <6, 6-12, >12 years, respectively. Conclusion: In children with CHB virus infection, the estimated rate of entry into the early immune-clearance phase was 28.0% for patients aged 12-18 years, which was significantly higher than that observed for children aged <12 years (11.7%; p=0.001).

• 대한전자공학회논문지TC
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• 제39권3호
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• pp.158-164
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• 2002

2-6 GHz 디지털 위상변위기 모듈을 설계, 제작하였다. 위상변위기 모듈에 사용된 MMIC 칩은 광대역을 구현하기 위해 Lange 커플러로 구성된 반사형 회로를 이용하여 설계 및 제작하였다. 위상변위기 모듈은 6.1°RMS 위상오차, 13.5 dB 최대 삽입손실과 각각, 8 dB와 10 dB의 입·출력 반사손실 특성을 갖는다. 32개의 위상 상태를 측정하기 위해서 컴퓨터를 사용하여 측정을 자동화 시켰다. 8×8 위상배열용 모듈들간의 RMS 삽입 위상오차는 최대 ±0.5°이내이고, 모듈들간의 평균 삽입손실 편차는 최대 ±0.5 dB를 넘지 않았다. 제작된 위상변위기 모듈의 크기는 45 × 22.5 × 60 ㎣. 이다.

• Asian-Australasian Journal of Animal Sciences
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• 제13권8호
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• pp.1137-1146
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• 2000

This study was carried out to establish an optimum number of phase feeding regimen which enable to reduce nutrients excretion without affecting growth performance and to investigate the effects of different feeding regimens on growth performance, nutrients excretion and carcass characteristics in finishing pigs. A total of 120 finishing pigs (an average initial body weight of 54.3 kg) were assigned to the feeding trial and 12 pigs were assigned to the metabolic trial. Treatments included one phase (54 to 104 kg), two phase (54 to 80 and 80 to 104 kg), three phase (54 to 70, 70 to 90 and 90 to 104 kg) and four phase (54 to 65, 65 to 80, 80 to 95, 95 to 104 kg) feeding regimens. Experimental diets were formulated to contain 16% crude protein for one phase feeding regimen, 16% and 12% crude protein for two phase feeding regimen, 16%, 14% and 12% crude protein for three phase feeding regimen, and 16%, 14.7%, 13.4% and 12% crude protein for four phase feeding regimen, respectively. Although there were no significant differences in any criteria measured during the entire experimental period, pigs reared in three phase feeding regimen grew slightly faster than those reared in other feeding regimens and showed a tendency to increase ADFI during the whole experimental period. The metabolic trial indicated that there were no significant differences in DM (dry matter), CP (crude protein) and P (phosphorus) digestibilities. However, fecal nutrient excretion except P was significantly influenced by feeding regimens. DM excretion of one phase feeding group was significantly higher than that of three phase feeding group and daily fecal N (nitrogen) excretion of one phase feeding group was higher than that of other phase feeding groups (p<0.05). Three and four phase feeding regimens resulted in 12% lower fecal N and DM excretion than one phase feeding regimen. Blood urea concentrations were lower for pigs reared in two, three and four phase feeding regimens than for those reared in one phase feeding regimen (p<0.05). Three phase feeding regimen for the finishing period showed better carcass grade than one phase feeding regimen, though the difference was not significant. The tenth rib fat thickness of pigs fed on four phase feeding regimen was reduced most and there was a trend that backfat thickness decreased as the number of phases increased. Feed cost per kg weight gain was significantly low in four phase feeding group than one phase feeding group (p<0.05). In summary, it seemed that producers generally oversupply the expensive nutrients for the finishing pigs. High nutrient diets do not always guarantee high growth rate of pigs and cause more unwanted nutrient excretion. It rather seems that meeting nutrient requirements for the each growth phase is more important for the reduction of pollutants and economical pork production.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.689-692
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• 2001

In this paper, the pizoelectric and dielectric properties of 0.95Pb(ZrxTil-x)O$_3$- 0.05Pb(Mn$\_$0.2/Fe$\_$0.4/W$\_$0.4/)O$_3$piezoelectric ceramics is investigated as a function of Zr/Ti mole ratio. Also, MPB(Morphotropic Phase Boundary) and optimal sintering temperature is studied using XRD and SEM. As a results, when Zr/Ti mole ratio is 52/48, electromechanical coupling factor, k$\_$p/, is 58[%], permittivity, $\varepsilon$$\^$T/$\_$33//$\varepsilon$0, is 1360 and piezoelectric strain constant, d$\_$33/ is 265[pC/N] and the piezoelectric and dielectric properties become maximum. Phase transition temperature of its ternary piezoelectric system is about 350[$^{\circ}C$]. From the XRD analysis, when Zr/Ti mole ratio is 52/48, tetragonal phase transits to rhombohedral phase. Also, From measuring results of the sintering density, when sintering temperature is 1050[$^{\circ}C$], sintering density become maximum and is about 7930[kg/㎥], and average grain size is about 2-3[$\mu\textrm{m}$].

• 전기전자학회논문지
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• 제19권3호
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• pp.335-341
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• 2015

최근 들어 철강의 두께 제어를 위해 고정밀도의 절대 위치 검출 센서에 대한 필요성은 증가하고 있다. 열악한 공장 환경 하에서 직선 운동하는 실린더의 절대 위치를 측정하기 위해서는 LVDT가 널리 사용된다. 본 논문에서는 1 미크론의 고해상도를 가지는 3상 LVDT 및 L/D (LVDT to digital) 변환기를 구현하였다. 이를 위하여 첫째 U, V, W 3상 정현파에 대한 시그널링을 FPGA로 설계하였다. 둘째 위치 정보에 대한 A상, B상 펄스 파형 출력 알고리즘을 구현하였다. 마지막으로 성능 평가를 위하여 기존의 센서들과 비교하였다. 실험 결과 직선성 편이 오차는 0.009788 [mm] 로써 2.2% 향상된 결과를 얻었고 정현파의 왜곡률은 평균 0.0751%로 기존보다 33%의 향상된 결과를 얻어 우수한 센서임을 입증하였다.

• 한국분말재료학회지
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• 제18권3호
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• pp.244-249
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• 2011

Spherical nanosized cobalt powder with an average size of 150-400 nm was successfully prepared at room temperature from cobalt sulfate heptahydrate ($CoSO_4{\cdot}7H_2O$). Wet chemical reduction method was adopted to synthesize nano cobalt powder and hypophosphorous acid ($H_3PO_2$) was used as reduction agent. Both the HCP and the FCC Co phase were developed while $CoSO_4{\cdot}7H_2O$ concentration ranged from 0.7 M to 1.1 M. Secondary phase such as $Co(OH)_2$ and $CO_3O_4$ were also observed. Peaks for the crystalline Co phase having HCP and FCC structure crystallized as increasing the concentration of $H_3PO_2$, indicating that the amount of reduction agent was enough to reduce $Co(OH)_2$. Consequently, a homogeneous Co phase could be developed without second phase when the $H_3PO_2/CoSO_4{\cdot}7H_2O$ ratio exceeded 7.

• 한국통신학회논문지
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• 제25권1A호
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• pp.10-17
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• 2000

본 논문에서는 가변 확산이득 (VSG) 구조를 갖는 멀티미디어 멀티레이트 DS/CDMA 시스템에서 PN 시퀀스의 위상에 따른 상관 특성을 보였고, 시퀀스 위상을 최적화 하였다. 멀티레이트 VSG-DS/CDMA 시스템의 경우에 시퀀스의 최적화는 동일 길이의 시퀀스들과는 물론, 다른 확산 이득을 갖는 다른 시퀀스들에 대해서 동시에 이루어져야 하므로 시퀀스의 최적화가 쉽지 않다. 따라서, 본 논문에서는 이러한 멀티레이트 시스템에서의 시퀀스 상관 특성을 살펴보았고, 이를 통해서 비트 오율을 최소화 시킬 수 있는 시퀀스 선택기준으로 MIN-AIP를 제시하였다. m 시퀀스와 Gold 시퀀스에 대한 성능분석 결과, MIN-AIP 기준에 의한 시퀀스 초기 위상의 선택기준이 성능을 가장 향상시킬 수 있는 최적의 선택기준이라는 결론을 얻을 수 있었다.