• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.4
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• pp.309-315
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• 2012

Catalytic combustion is generally accepted as one of the environmentally preferred alternatives for heat and power from fossil fuels, as it has the advantage of stable combustion under very lean conditions with such low emissions as UHC, CO, and NOx. In this work, therefore, comparative numerical studies on the catalytic combustion behaviors over Pd-based catalysts have been conducted with the gaseous $CH_4$, $C_2H_6$, and $C_3H_8$. In the following, after introducing the governing equations with 1D channel and Langmuir-Hinshelwood models, numerical investigations on the catalyst performance are conducted by changing such various parameters as inlet temperature, excess air ratio, and space velocity. The numerical results show that outlet temperature and conversion of $C_3H_8$ are highest among others because of its chemical structure and reactivity.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.3
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• pp.335-340
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• 2012

The data used came from two trials undertaken under the same climatic conditions (spring-summer). In both trials pluriparious buffaloes were utilized similar in weight, body condition score, and milk production from the previous year. From the first trial the data used was from the sub-period 23-88 DIM provided by seven animals fed ad libitum with diet A (6.69 MJ/kg DM; 158.30 g/kg of crude protein) with a forage/concentrate ratio of 48/52. From the second trial the data used was from the sub-period 33-90 DIM provided by seven animals fed ad libitum with diet B (6.63 MJ/kg DM; 179.50 g/kg of crude protein) and by seven animals fed ad libitum with diet C (5.99 MJ/kg DM; 155.40 g/kg of crude protein), each of the diets had the same forage/concentrate ratio (53/47). A significant difference was found in milk production between group B and C (13.08 vs. 11.56 kg/d, p<0.05), an intermediate production (12.10 kg/d) was noted in group A. A significant difference was found between fat (76.58 vs. 69.24 g/kg, p<0.05), protein (46.14 vs. 43.16 g/kg, p<0.05) and casein (39.94 vs. 34.98 g/kg, p<0.05) of the milk of group B with respect to group A. The milk of group C gave fat values (71.80 g/kg), protein (45.52 g/kg) and casein (39.06 g/kg) statistically equal to those of group B. The milk of groups B and C, in respect to the milk of group A, gave values of $K_{20}$ (1.77, 1.82 vs. 3.68 min, p<0.05), statistically lower and values of $A_{30}$ (48.28, 47.27 vs. 40.64 mm, p<0.05) statistically higher. Two simple linear regressions were calculated where the independent variable (x) was the daily standardized milk production, the dependent variable (y) or the daily intake of net energy or crude protein. Equation 1) NE (MJ/d) = 74.4049+2.8308${\times}$kg of normalized milk; equation 2) CP (kg/d) = 1.4507+0.1085${\times}$kg of normalized milk, both the equations were significant (p<0.05) with determination coefficients of 0.58 and 0.50 respectively. For a production of normalized milk that varies from 9 to 13 kg, the respective energy-protein concentrations fluctuate from 6.09 to 6.78 MJ/kg DM and from 148.00 to 174.46 g/kg DM.

• Ocean and Polar Research
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• v.40 no.3
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• pp.115-125
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• 2018

Production from copepodite IV to adult of two euchaetid species Euchaeta plana and Paraeuchaeta russelli was measured at the southeastern sea of Korea from April to November, 2014. The mean density was $2.0ind\;m^{-3}$ for E. plana and $4.1ind\;m^{-3}$ for P. russelli, with the high contribution of copepodite V to total density. The densities of total individuals, adult females and eggs were highest in November for both species. The mean egg production rate (EPR) was $1.7eggs\;female^{-1}\;d^{-1}$ for E. plana and $3.1eggs\;female^{-1}\;d^{-1}$ for P. russelli. Both of them showed the highest EPR in September but zero EPR in summer. The mean weight-specific EPR was $0.038d^{-1}$ for E. plana and $0.079d^{-1}$ for P. russelli. The mean total production rates of E. plana and P. russelli were $5.3{\mu}g\;C\;m^{-3}\;d^{-1}$ and $17.8{\mu}g\;C\;m^{-3}\;d^{-1}$, respectively, with the largest production in November. The mean Production/Biomass ratio was $0.06d^{-1}$ for E. plana and $0.07d^{-1}$ for P. russelli, with its peak in September for both. The total production of E. plana and P. russelli was positively correlated with the density of a copepod Oncaea venusta, rather than chl-a concentration, indicating that the two copepods might be carnivores. This study evaluates the contribution of euchaetids to the copepod community in the southeastern sea of Korea.

• Korean Journal of Applied Biomechanics
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• v.27 no.1
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• pp.1-7
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• 2017

Objective: The purpose of this study was to analyze the relationship between ground reaction force (GRF) and attack time according to the position of hand segments during counter attack in Kendo. Method: The participants consisted of 10 kendo athletes (mean age: $21.50{\pm}1.95yr$, mean height: $175.58{\pm}5.02cm$, mean body weight: $70.96{\pm}9.47kg$) who performed standard head strikes (A) and counter attack with a preferred hand position of +10 cm (B), 0 cm (C), and -10 cm (D). One force-plate (AMTI-OR-7., USA) was used to collect GRF data at a sample rate of 1,000 Hz. The variables analyzed were the attack time, medial-lateral GRF, anterior-posterior GRF (AP GRF), peak vertical force (PVF), and loading rate. Results: The total attack time was shorter in types A and C than in types C and D. The AP GRF, PVF, and loading rate had significantly higher forces in types C and D than in types A and C. The attack time (bilateral and unilateral leg support and total) was positively correlated with the GRF variables (vertical GRF and loading rate) during the counter attack in Kendo (r = 0.779 [$R^2=0.607$], p < 0.001). Conclusion: The positions of the hand segments can be changed by various conditions of the opponent in Kendo competitions; however, the position preferred by an individual can promote the successful ratio of the counter attack.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.6
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• pp.539-543
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• 2006

Lodging is classified as root lodging caused by the loss of supporting force in the root, bending caused by the deformation of the stem and breaking where the stem breaks down as loads exceeding critical elasticity were applied. This research excluded breaking which is not in a state of equilibrium and tried to partition the level of lodging using an algebraic model in root lodging and stem lodging, or bending. When a vertical load was applied, the deformation of the stem of rice plant showed the form of a quadratic equation. The trace of the panicle neck in the process of lodging was an ellipse-shape. When loading was pure root lodging, the trace of the panicle neck became a circle of which culm length is the radius. When it was a pure stem lodging, the trace of the panicle neck is an ellipse of which major axis is culm length and minor axis is 0.64* culm length. When both stem lodging and root lodging occurred in a natural setting, the partitioning of lodging can be calculated by a formula using eccentricity of an ellipse, S=e*100/0.768(S is the ratio of stem lodging in the whole lodging, e is eccentricity of the ellipse). This method is expected to be useful in simple lodging partitioning. We could also calculate the partitioning of stem lodging and root lodging as units of angles as an accuracy method, by using a straight line calculated by differentiating a quadratic equation of stem deformation at the origin of the coordinates. These two methods for dividing root and stem lodging showed different values. However, each of them showed almost same values with different lodging degree in one plant.

• Journal of the Korea Concrete Institute
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• v.18 no.5 s.95
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• pp.611-620
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• 2006

In the shear failure mechanism of a beam, beam and arch actions always exist simultaneously. According to the shear span to depth ratio, the proportion between these two actions is varied and the contribution of these actions to shear capacity is changed. Moreover, the current codes provide recommendations based on experimental results of normal strength concrete, so the application range of concrete strength must be extended. Based on this mechanism and new requirement, a simplified analytical equation for shear capacity prediction of reinforced high strength concrete beams without stirrups is proposed. To reflect the change in the contribution between these actions, stress variation in the longitudinal reinforcement along the span is considered by use of the Jenq and Shah Model. Dowel action with horizontal splitting failure and shear friction between cracks are also taken into account. ize effect is included to derive a more precise equation. Regression analysis is performed to determine each variable and simplify the equation. And, the formula derived from theoretical approaches is evaluated by comparison with numerous experimental data, which are in broad range of concrete strength(especially in high strength concrete), shear span to depth ratio, geometrical size and longitudinal steel ratio. It is shown that the proposed equation is more accurate and simpler than other empirical equations, so a wide range of a/d can be considered in one equation.

• Proceedings of the Korean Society of Organic Agriculture Conference
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• 2009.12a
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• pp.304-305
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• 2009

시설재배지의 토양화학성 변화는 작물재배 기간 시비한 화학비료에서 유래된 무기성분 뿐만아니라, 가축분퇴비의 질소성분의 토양잔류량이 요소비료 보다 9.4배 많아 염류집적 주 요인이라는 보고('05 경기도)가 시사하는 봐와 같이 유기자원으로 시용하는 가축분 등의 부산물비료의 무기화에서 유래된 비료성분이 토양염류집적 및 토양환경악화에 더 큰 영향을 미칠 수 있다. 시설재배지의 유기물자원 시용기준이 토양의 특성에 관계 없이 작물에 따라 양적인 시험성적이 주로되어 있으며, 토양검정에 의한 시용기준도 유기물함량에 따라 볏짚, 우분, 돈분 및 계분으로 돠어 있다. 일반노지와 달리 시설재배지에서는 유기물함량이 토양의 비옥도 및 작물생육에 영향을 미치는 것 보다는 토양의 전기전도도(EC)가 더 중요한 작물생육 조건이 될 수 있다. 따라서 토양의 특성에 따라 물질순환에 의한 유기자원 시용기준으로 개선할 필요성이 있다. 시설재배지의 장기적인 토양관리를 위하여 유기물자원에 의한 토양환경 개선 효과를 구명하고자. 무처리, 가축분부산 물비료 관행 시용 기준 대비 볏짚 등 5개의 유기자원을 토양의 무기태질소 함량 대비 유기자원의 탄소함량을 C/N율 10 조절량을 시용하여 시험하였고, 또한 토양의 전기전도도(EC)가 상이한 3개( <2.0 dS/m, 2.0~6.0 dS/m, 6.0 dS/m<)토양에 유기물자원(우드칩)을 C/N율 10, 20, 30 조절하여 수박을 시험작물로 비닐하우스에서 재배하여 수행하였다. 시험 후 토양의 전기전도도(EC)는 시험 전에 비하여 시험 후 토양에서 가축분부산물비료는7% 증가되었으나 유기물자원 처리는 26~33% 경감되는 효과가 있었다. 수박의 과중은 무처리를 제외하고 처리간에 차이가 없었다. 유기물자원 C/N율 조절간에는 시험전 토양의 EC에 따라 차이가 있어 C/N 10 조절에서는 26~44%, C/N 20 조절에서는 30~51%, C/N 30 조절에서는 27~48% 경감효과가 있었으며, 3토양의 평균 토양EC 경감율은 C/N 10, 20, 30 조절에서 각각 34, 39 및 38 % 이었다. 수박의 생육 및 과중은 토양의 C/N율 조절간에는 차이가 없었으나, 토양의 EC 간에는 토양의 EC가 6.0dS/m 이상 토양에서 가장 낮았다. 따라서 탄소원의 유기자원을 C/N율 조절에 의한 시용기준 개선으로 토양의 무기태질소와 토양의 전기전도도(EC)를 경감시켜 친환경적 토양관리와 수박의 수량과 품질을 향상시킬 수 있을 것으로 평가되었다.

• Journal of Applied Biological Chemistry
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• v.55 no.1
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• pp.13-17
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• 2012

In order to enzymatically produce chitooligosaccharide using the crude enzyme preparation from Bacillus cereus D-11, we first studied the optimal reaction conditions. It was found that the optimal temperature for hydrolysis of chitosan was $55^{\circ}C$. The ratio of enzyme/substrate should not be lower than 0.13 U/mg in the reaction mixture. The enzyme activity was stable below $50^{\circ}C$. The products of enzymatic reaction were analyzed by both thin layer chromatography and high performance liquid chromatography. Under the appropriate condition, chitosan was hydrolyzed using the enzyme preparation. The resulting chitooligosaccharides were purified and separated by Dowex ($H^+$) ion exchange chromatography. From 4 g soluble chitosan, 0.95 g $(GlcN)_2$, 1.43 g $(GlcN)_3$, and 1.18 g $(GlcN)_4$ were recovered.

• Journal of Biosystems Engineering
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• v.34 no.2
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• pp.71-76
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• 2009

This study was conducted to investigate the load acting on a tractor engine when it delivers the maximum power at drawbar. The results of the drawbar tests on the 5 locally-made and 14 imported tractors conducted at NIAE in 2004, and the 15 tractors tested at OECD test stations in foreign countries were analyzed and presented by the torque load ratio, defined as a ratio of the engine torque load caused by drawbar pull to its full-load capacity, as a function of pull speed. The NIAE test results showed that the torque load ratio increased from 20 to 80% with pull speed less than 5 km/h. At speeds faster than 5 km/h, it was 80${\sim}$110% regardless of the pull speed. However, the OECD test results showed that the torque load ratio was evaluated mostly to be 70${\sim}$90% in the entire pull speed range. The same trend was also shown for the maximum drawbar load. The difference in the torque load ratio may be attributable to bias-ply tires for locally-made and some imported tractors. It is also suggested that the input torque load may be increased safely up to 120% of the full load capacity of the tractor engine for an accelerated life test of tractor transmissions.

• Journal of the Korea Society of Computer and Information
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• v.19 no.10
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• pp.71-79
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• 2014

In this paper, the microstrip array antenna is studied to replace the parabolic antenna in the direct satellite reception. A microstrip array antenna has been used in extremely limited area, but if it is applied to practical life like a direct satellite reception antenna, we expect that it will be used in various way. First of all, if we use a microstrip array antenna for a direct satellite reception antenna, it should be guaranteed characteristics of broadband frequency. Therefore, the goal of this paper is designing technique an antenna which guarantees broadband frequency band for a direct satellite reception. In this paper, the proposed microstrip antenna is fed by orthogonal two feed lines to a rectangular patch and a sequentially rotated feeding technique is designed proposed for a good axial ratio in broadband frequency band. The rectangular patch is designed to satellite reception band, and the width and length are W=L=8.9 mm ($0.352{\lambda}o$) respectively. The antenna's ground plane has dimensions of $250{\times}250mm$. The experimental results verify that the proposed antenna had the axial ratio of above 1dB broader than that of the conventional feeding antenna. In order to verify the performance, a $8{\times}8$ array having two pairs was fabricated and tested. The maximum gain is 20.8 dB, the sidelobe level confirm less than -10 dB. It is verified by link budget calculation that C/N=6.7 dB can be obtained for domestic use if this proposed antenna is used in Koreasat reception system.