• Journal of Ginseng Research
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• 제7권1호
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• pp.23-36
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• 1983

This study was devised to observe the nutritional effects of the diets supplemented with the leaf or trunk in rats. The male albino rats (110 heads), Sprague-Dowley strain weighing 75g to 79g, were used as the experimental aninl mils. The animals were divided into twelve diet groups and maintained with corresponding diet for 40 days, and then sacrificed. The growth rate, the consumption and efficiency ratios of the food and protein, the absorption rates of carbohydrate, lipid and protein, and the utilization rates of energy were determined during the feeding term. The results obtained are summarized as follows: 1) The growth rate, the consumption and efficiency ratios of the food and protein in each experimental diet group added ginseng steamed leaf or trunk were higher than those in experimental group A which has the diet supplemented with ginseng raw leaf of trunk. 2) The absorption rates of the carbohydrate were above 96%, higher than those or the control group, But those of fat, protein and the utilization rate of energy in each experimental diet group were generally lower than those in the control group.

• Bulletin of the Korean Chemical Society
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• 제12권5호
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• pp.510-514
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• 1991

Second-order rate constants have been determined spectrophotometrically for reactions of S-p-nitrophenyl substituted thiobenzoates with various phenoxide ions and S-aryl substituted thiobenzoates with $HO^-$ ion. Thiol esters have been found to be more reactive than the corresponding oxygen esters toward phenoxide ions. The high reactivity of thiol esters relative to oxygen esters becomes insignificant as the basicity of the nucleophile increases. Furthermore, the highly basic $HO^-$ ion is less reactive toward thiol esters than oxygen esters. The significant dependence of the reactivity of thiol esters on the basicity of nucleophiles has been attributed to the nature of the HSAB principle. The present kinetic study has also revealed that the reactivity of thiol esters compared to oxygen esters is not so pronounced as expected based on the enhanced nucleofugicity of thiol esters. However, the effects of substituents in the nucleophile and in the acyl moiety of the substrate on rate appear to be significant. These kinetic results have led to a conclusion that the present reactions proceed via a rate-determining formation of a tetrahedral intermediate followed by a fast breakdown of it. The magnitude of the ${\beta}$ values shows no tendency either to increase or to decrease with the intrinsic reactivity of the reagents. The constancy of ${\beta}$ values in the present system is suggestive that the RSP should have limited applicability.

• Geomechanics and Engineering
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• 제17권4호
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• pp.393-403
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• 2019

The cycling impact test of red sandstone soil under different axial pressure and different impact loads are conducted to reveal the mechanical properties and energy consumption mechanism of red sandstone soil with static-dynamic coupling loading. The results show that: Under the action of different axial pressure and different impact loads, the peak stress of the specimen increases, and then tends to be stable with the times of impact. With the increase of impact times, the specific energy absorption value of the red sandstone soil specimen is increased first and then gentle development trend. When the impact loads are certain, the larger the axial pressure is, the smaller the peak value of energy absorption, which indicates that the energy utilization rate is not high under the condition of large axial pressure. Through the analysis of energy utilization, it is found that the smaller the impact load, the higher the energy utilization rate. The greater the axial pressure, the lower the energy utilization rate. when the axial pressure is large, the impact loads corresponding to the maximum values of reflectivity, transmissivity and absorptivity are the same. The relationship between reflectivity and transmissivity is negatively correlated.

• 대한방사선기술학회지:방사선기술과학
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• 제45권4호
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• pp.355-363
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• 2022

This study was to investigate the prevalence rate of musculoskeletal disorders in relation to general characteristic factors, living environment factors, and work environment factors for sonographer's. For the response questions, the guidelines for musculoskeletal burden work were used. For statistical analysis, SPSS 26.0 version was used. For the common body parts of the sonographer's who responded, the prevalence was investigated by dividing the group into a group with high pain or discomfort and a group with low pain or discomfort according to the degree to which they experienced symptoms during the past 12 months. Multiple logistic regression analysis was used to determine the variance inflation factor(VIF), odds ratio (OR) and corresponding 95% confidence interval (CI). A p-value of <0.05 was considered statistically significant. As a result, housework hours, examination history, regular physical activity, number of patient examinations per day, and sitting posture were investigated as variables for rate musculoskeletal disorders. The sonographer's occupational group was found to have a high prevalence rate of musculoskeletal disorders like various other occupational groups. Based on the results of this study, it is judged that musculoskeletal disorders can be reduced by recognizing musculoskeletal disorders and improving work environment factors.

• Archives of Plastic Surgery
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• 제49권2호
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• pp.215-220
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• 2022

Background In Japan, there is a large regional disparity in plastic surgery availability. In order for plastic surgery to be widely available for all citizens, it is essential for at least one plastic surgery facility to be located in each secondary medical zone. Methods Using the Japan Society of Plastic and Reconstructive Surgery homepage and some databases, we extracted data on secondary medical zones that do not have a plastic surgery facility. The national and regional coverage rates were calculated. The coverage rate for each group divided by the degree of population concentration was also calculated. Results We found that 147 of 344 secondary medical zones did not have a plastic surgery facility, and the area coverage rate was found to be 57.27% nationwide. The coverage rate in terms of population was 87.07% (correlation coefficient of area and population coverage = 0.983). The area coverage rates in Hokkaido-Tohoku, Kanto, Chubu, Kansai, Chugoku-Shikoku, and Kyushu-Okinawa districts were 47.46, 72.15, 76.47, 62.79, 52.08, and 32.81%, respectively. The corresponding population coverage rates were 79.92, 91.62, 94.27, 90.59, 80.68, and 69.54%, respectively. The area coverage rates in metropolitan areas, provincial cities, and rural areas were 98.08, 75.90, and 15.87%, respectively. In contrast, the area coverage rate of dermatology was 62.79% and that of orthopaedics was 97.09%. Conclusion Unfortunately, it is estimated that more than 40% of secondary medical zones are underserved by plastic surgery, and 13% of the population is not able to fully benefit from this specialty in Japan.

• Structural Engineering and Mechanics
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• 제88권6호
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• pp.521-533
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• 2023

In the present study, the finite volume method is applied for the thermal performance prediction of the natural ventilation system using vertical solar chimney whereas, design parameters are optimized through the response surface methodology (RSM). The computational simulations are performed for various parameters of the solar chimney such as absorber temperature (40≤T_abs≤70℃), inlet temperature (20≤T₀≤30℃), inlet height of (0.1≤h≤0.2 m) and chimney width (0.1≤d≤0.2 m). Analysis of variance (ANOVA) was carried out to identify the design parameters that influence the average Nusselt number (Nu) and mass flow rate (ṁ). Then, quadratic polynomial regression models were developed to predict of all the response parameters. Consequently, numerical and graphical optimizations were performed to achieve multi-objective optimization for the desired criteria. According to the desirability function approach, it can be seen that the optimum objective functions are Nu=25.67 and ṁ=24.68 kg/h·m, corresponding to design parameters h=0.18 m, d=0.2 m, T_abs=46.81℃ and T₀=20℃. The optimal ventilation flow rate is enhanced by about 96.65% compared to the minimum ventilation rate, while solar energy consumption is reduced by 49.54% compared to the maximum ventilation rate.

• 드라이브 ㆍ 컨트롤
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• 제20권4호
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• pp.123-132
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• 2023

In disaster situations, to facilitate rapid drainage, electric underwater pumps are installed manually. This poses a high risk of electric shock accidents due to a short circuit, and a lot of time is required for hose connection and installation of electrical devices. To solve these problems, a Venturi pump using the venturi effect without external power is used. However, Venturi pumps that operate without external power make it difficult to install flow sensors such as electric devices; consequently, it is difficult to check the real-time flow rate. This paper proposes a flow estimation logic to replace the function of the flow sensor for the venturi pump . To develop the flow estimation logic, the flow characteristics of the venturi pump, according to the operating conditions, were checked. After that, the relationship with the flow rate of the venturi pump was defined using a pressure sensor corresponding to a low-cost sensor. Finally, an analysis of the estimation error was performed using the developed flow estimation logic.

• 한국항행학회논문지
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• 제7권2호
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• pp.141-148
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• 2003

본 논문에서는 미상 디지털 통신 신호의 심볼율을 검출하기 위한 기술들을 소개하고 그 성능을 비교해 본다. 심볼율은 delay and multiplier, square law 또는 Hilbert 변환을 이용한 방법 등의 회로를 통과한 신호의 전력스펙트럼 밀도에서 검출해 낼 수 있다. 이러한 회로들을 통과한 신호를 이산 푸리에 변환(discrete Fourier Transform) 한 결과에서 많은 스펙트럼 라인과 복수개의 피크(peak)가 검출되고 그 중 첫 번째 피크가 심볼율을 나타내는 주파수에 위치하게 된다. 만약 해당 심볼율이 아닌 다른 주파수상의 스펙트럼 라인의 값이 첫 번째 피크보다 크다면 심볼율은 잘못 검출될 것이다. 그러므로 첫 번째 피크의 값과 가장 큰 주변 스펙트럼 라인의 값의 비를 이용하여 심볼율 검출기의 성능을 비교하였다. MPSK 변조 방식에서는 -20dB 이하의 Es/N0에서는 delay and multiplier가 가장 우수한 성능을 보였고 -20dB 이상의 Es/N0에서는 Hilbert 변환 방식이 더 좋은 성능을 나타내었다. 또한 QAM 변조 방식에서 delay and multiplier 회로는 낮은 Es/N0에서는 심볼율을 검출할 수 없으며 square law 방식은 MPSK 변조 방식에서 보다 우수한 성능을 나타내었다.

• 대한전자공학회논문지TC
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• 제48권3호
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• pp.19-27
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• 2011

광 네트워크 기술의 발달로 인해 오늘날 대부분의 네트워크는 수십 Gb/s를 지원한다. UDT(UDP-based Data Transfer protocol)는 대역폭과 지연시간이 큰 네트워크 환경에서 대용량 데이터 전송을 위한 프로토콜이다. 그러나 UDT는 고정된 sync-interval(0.01초) 간격으로 주기적인 rate control을 실행한다. 네트워크 트래픽 상태의 변화가 심한 환경에서는 sync-interval 동안 가용 대역폭을 충분히 활용하지 못하는 문제점이 발생한다. 본 논문은 sync-interval 구간에서 네트워크 트래픽 상태에 적응적인 rate control 기법을 제안한다. 네트워크 트래픽 상태는 RTT 변화를 바탕으로 판단한다. 제안 기법은 네트워크 상태를 4개의 구간으로 설정하여 패킷 sending period를 조절함으로써 rate control을 수행한다. 시뮬레이션 결과를 통하여 기존 UDT에 비해 throughput 과 안정성이 향상되었음을 보였다.

• Structural Engineering and Mechanics
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• 제89권6호
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• pp.617-626
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• 2024

The study investigated the behavior of plain and fibered Ultra-High Performance Concrete (UHPC) beams under varying loading conditions using integrated analysis of the flexure and acoustic emission tests. The loading rate of testing is -0.25 -2 mm/min. It is observed that on increasing loading rate, flexural strength increases, and toughness decreases. The acoustic emission testing revealed that higher loading rates accelerate crack propagation. Fiber effect and matrix cracking are identified as significant contributors to the release of acoustic emission energy, with fiber rupture/failure and matrix cracking showing rate-dependent behavior. Crack classification analysis indicated that the rise angle (RA) value decreased under quasi-static loading. The average frequency (AF) value increased with the loading rate, but this trend reversed under rate-dependent conditions. K-means analysis identified distinct clusters of crack types with unique frequency and duration characteristics at different loading rates. Furthermore, the historic index and signal strength decreased with increasing loading rate after peak capacity, while the severity index increased in the post-peak zone, indicating more severe damage. The sudden rise in the historic index and cumulative signal strength indicates the possibility of several occurrences, such as the emergence of a significant crack, shifts in cracking modes, abrupt failure, or notable fiber debonding/pull-out. Moreover, there is a distinct rise in the number of AE knees corresponding to the increase in loading rate. The crack mapping from acoustic emission testing aligned with observed failure patterns, validating its use in structural health monitoring.