• International Journal of Automotive Technology
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• 제6권5호
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• pp.467-473
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• 2005

A continuously variable transmission (CVT) with an inner spherical traction drive was conceptually designed for bicycle usage. The range of the overall speed ratio is from 1.0 to 4.5. The rated power and pedal speed are 100 Watts and 6 rad/s, respectively. The peculiar packageability, high-level power efficiency and high torque capacity were considered in the design process. A compact CVT that can be installed within a $244\times125\times160mm^3$ space and is above 0.9 in efficiency for the rated values was numerically designed. The distribution of efficiency according to the input torque and input speed were calculated. Gradeability in the prescribed operation mode was simulated.

• 대한임베디드공학회논문지
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• 제18권1호
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• pp.9-17
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• 2023

This paper relates to the development of a device for measuring the efficiency of a solar panel based on a variable constant current, and proposed a standard for reuse of the solar panel. By applying a variable constant current circuit to a solar panel efficiency measuring device, it was easy to apply a maximum power point tracking (MPPT) algorithm. In addition, a load dispersion method was applied to measure the efficiency of a high-capacity solar panel. and it is possible to solve a problematic thermal runaway during a MOSFET parallel operation by applying the load dispersion method. As a result of the experiment, the solar panel efficiency measuring device was able to accommodate a large solar panel of 350W, which is the maximum measurement goal. In this paper, the validity was confirmed through the 310W solar panel efficiency measurement experiment collected after removal.

• Steel and Composite Structures
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• 제45권2호
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• pp.219-230
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• 2022

The aim of this paper is to study the mechanical behaviors of the cold-formed thin-walled steel and reinforced concrete sandwich composite slab (CTS&RC-SCS) under vertical loads and to develop the calculation methods of its flexural bearing capacity and section stiffness. Two CTS&RC-SCS specimens were designed and manufactured to carry out the static loading test, and meanwhile, the numerical simulation analyses based on finite element method were implemented. The comparison between experimental results and numerical analysis results shows that the CTS&RC-SCS has good flexural capacity and ductility, and the accuracy and rationality of the numerical simulation analysis are verified. Further, the variable parameter analysis results indicate that neither increasing the concrete strength grade nor increasing the thickness of C-sections can significantly improve the flexural capacity of CTS&RC-SCS. With the increase of the ratio of longitudinal bars and the thickness of the composite slab, the flexural capacity of CTS&RC-SCS will be significantly increased. On the basis of experimental research and numerical analysis above, the calculation formula of the flexural capacity of CTS&RC-SCS was deduced according to the plastic section design theory, and section stiffness calculation formula was proposed according to the theory of transformed section. In terms of the ultimate flexural capacity and mid-span deflection, the calculated values based on the formulas and the experimental values are in good agreement.

• Steel and Composite Structures
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• 제47권3호
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• pp.437-450
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• 2023

A half open cross section built-up column, namely cold-formed thin-walled steel built-up column with 12-limbsection (CTSBC-12) is put forward. To deeply reveal the mechanical behaviors of CTSBC-12 under axial compression and put forward its calculation formula of axial bearing capacity, based on the previous axial compression experimental research, the finite element analysis (FEA) is conducted on 9 CTSBC-12 specimens, and then the variable parameter analysis is carried out. The results show the FEA is in good agreement with the experimental research, the ultimate bearing capacity error is within 10%. When the slenderness ratio is more than 96.54, the ultimate bearing capacity of CTSBC-12 decreases rapidly, and the failure mode changes from local buckling to global buckling. With the local buckling failure mode unchanged, the ultimate bearing capacity decreases gradually as the ratio of web height to thickness increases. Three methods are used for calculating the ultimate bearing capacity, the direct strength method of AISI S100-2007 gives result of ultimate axial load which is closest to the test and FEA results. But for simplicity and practicality, a simplified axial bearing capacity formula is proposed, which has better calculation accuracy with the slenderness ratio changing from 30 to 100.

• Clinical and Experimental Reproductive Medicine
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• 제30권1호
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• pp.105-109
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• 2003

Objective s: To assess the fertilizing capacity using sperm penetration assay (SPA) to predict the outcome of the in vitro fertilization-embryo transfer (IVF-ET) outcome. Materials and Methods: Semen samples were provided by 129 patients undergoing IVF. We attempted to correlate the extent of sperm penetration under enhanced SPA protocol with the results of fertilization, cleavage, preimplantation embryo development, and pregnancy. Results: Univariate analysis demonstrated a statistically significant correlation between fertilizing capacity and motility, kinetics, fertilization, cleavage and embryo development, and pregnancy rate. By logistic regression analysis, fertilizing capacity was found to be the only variable that was statistically significant with respect to pregnancy rate. Fertilizing capacity, cleavage rate and pregnant rate were significantly higher in pregnant group. However, the fertilization rates was comparable with both group. Conclusions: Lower fertilizing capacity could denote a poorer prognosis for establishing a pregnancy, even after satisfactory fertilization rate is achieved.

• 농촌지도와개발
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• 제24권4호
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• pp.279-293
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• 2017

Community attachment is an important variable for affecting community satisfaction. The study aims to identify the factors influencing community satisfaction on rural community capacity. Particularly, the study examine the moderating effects of the community attachment between community capacity and community satisfaction. Data were collected from 289 residents of rural villages through questionnaires. Results of a factor analysis yielded four dimensions of community capacity which are learning opportunity and technique, leadership, grasping problem, and community attitude. Results show that learning opportunity and community attitude among four dimensions of community capacities have significance for community satisfaction. And community attachment among community capacity factors has a positive effects as a moderator between community capacity and community satisfaction. Results also indicated that community attitude has an interactional effects with moderator. It was suggested that community attachment should be considered in rural community development policy.

• The Journal of Asian Finance, Economics and Business
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• 제8권11호
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• pp.31-39
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• 2021

This study empirically examines the proposition that the domestic fundamentals of a nation can emerge as absorptive capacity factors to reap the benefits of inward FDI. The study is contextualized in Asia, set from1982 to 2017, and data is grouped into low-income and lower-middle-income economies, in comparison to high-income and upper-middle-income economies, catering to different geographical regions within Asia. The investigation is based on a series of absorptive capacity factors such as infrastructure, human capital, domestic credit, and health indicator. The methodological analysis is premised on dynamic panel structure and employs the Generalized Method of Moments (GMM) estimation technique. The empirical findings suggest that that the infrastructure variable appears to be the major absorptive capacity factor for both groups of countries. The health indicator, on the other hand, can help reap the benefits of inward FDI, but only if the threshold level is met. The selected economies must achieve this threshold level to reap the benefits of FDI. To absorb the benefits of inward FDI, countries must be proactive in providing sound infrastructure and implementing proper healthcare measures.

• FOCUS: LIFE SCIENCE
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• 제1호
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• pp.9.1-9.5
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• 2024

Method development for complex low molecular mass (LMM) samples using reversed-phase (RP) separation conditions presents significant challenges due to the presence of many unknown analytes over wide concentration ranges. This guide aims to optimize method parameters-column length (L), temperature (T), flow rate (F), and final mobile phase conditions (Øfinal)-to maximize separation peak capacity. Validated by prior research, this protocol benefits laboratories dealing with metabolomics, natural products, and contaminant screening. This practical guide provides a structured approach to maximizing peak capacity for complex LMM separations. It complements computational optimization strategies and offers a step-by-step method development process. The Snyder-Dolan test is highlighted as essential for determining the need for gradient or isocratic elution and guiding column length decisions. The decision tree framework helps analysts prioritize variable optimization to develop effective separation methods for complex samples.

• 동력기계공학회지
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• 제12권1호
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• pp.13-19
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• 2008

In this study, a variable induction and exhaust system is applied to turbocharged diesel engine to improve the volumetric efficiency, especially, in a low and transient engine speed range where much of the pollutant matters are expelled out. The volumetric efficiency is known as one of the most important factor which affects significantly engine performance, fuel economy and further emission and noise level. As the torque increase with the engine speed up, the gas flow in an exhaust pipe become pulsating and then has an effect on boost up capacity of air charging into the cylinder and expelling capacity to atmosphere simultaneously. But at a low and idling speed, the pulsation effect was not so significant. Accordingly, resonator was employed to compensate their loss. The variable induction system consists of the secondary pipe, resonator, intercooler, and torque variance were examined with extended operating conditions. In the mean time, for interpretation and well understanding for the phenomena of wave action that arising during intake and exhaust process between turbocharger and variable intake system, the concept of the combined supercharging was introduced. Some of results are depicted which deal with a pressure history during valve events of induction process. Consequently, by the governing of these phase and amplitude of pulsating wave, it enables us to estimate and evaluate for the intake system performance and also, designing stage of the system layout.

• 한국강구조학회 논문집
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• 제24권4호
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• pp.411-422
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• 2012

본 연구의 목적은 기존의 철선일체형 데크플레이트에 오메가형 강판을 삽입한 중공 데크플레이트 슬래브의 휨 및 전단내력의 구조성능을 평가하는 것이다. 휨 및 전단내력에 대한 구조성능을 평가하기 위해서 슬래브 두께를 주요 변수로 하여 150mm 실험체 5개와 200mm 실험체 3개를 제작하였다. 각 실험체는 기존의 철선일체형 데크플레이트 슬래브 1개씩과 콘크리트 토핑두께를 변수로 하는 2개씩의 실험체로 구성되어 있다. 실험결과 중공부에 형성에 의한 휨 및 전단내력에 대한 구조성능의 저하는 없는 것으로 나타났다. 따라서 중공 데크플레이트는 효과적으로 콘크리트 사용량을 저감하면서도 기존의 철선일체형 데크플레이트에 준하는 구조성능을 갖춘 것으로 판단된다.