• Journal of Electrical Engineering and Technology
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• v.11 no.2
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• pp.367-376
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• 2016

This paper presents a cell balancing method for a single switch flyback converter with a multi-winding transformer. The conventional method using a flyback converter with a multi-winding transformer is simple and easy to control, but the voltage of each secondary winding coil might be non-uniform because of the unequal effective turn-ratio. In particular, it is difficult to control the non-uniform effect using turn-ratios because secondary coil has a limited number of turns. The non-uniform secondary voltages disturb the cell balancing procedure and induce an unbalance in cell voltages. Individual cell control by adding a switch for each cell can reduce the undesirable effect. However, the circuit becomes bulky, resulting in additional loss. The proposed method here uses the conventional flyback converter with an adjustment made to the output filters of the cells, instead of the additional switch. The magnitude of voltage applied to a particular cell can be reduced or increased according to the adjusted filter and the selected switching frequency. An analysis of the conventional converter configuration and the filter design method reveals the possibility of adequate cell balancing control without any additional switch on the secondary side.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.696-696
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• 2013

Solid Oxide Fuel Cells (SOFCs) have been gaining academic/industrial attention due to the unique high efficiency and minimized pollution emission. SOFCs are an electrochemical system composed of dissimilar materials which operates at relatively high temperatures ranging from 800 to 1000oC. The cell performance is critically dependent on the inherent properties and integration processing of the constituents, a cathode, an electrolyte, an anode, and an interconnect in addition to the sealing materials. In particular, the gas transport, ion transport, and by-product removal also affect the cell performance, in terms of open cell voltages, and cell powers. In particular, the polarization of cathode materials is one of the main sources which affects the overall function in SOFCs. Up to now, there have been studies on the materials design and microstructure design of the component materials. The current work reports the effect of thin film processing on cathode polarization in solid oxide fuel cells. The polarization issues are discussed in terms of dc- and ac-based electrical characterizations. The potential of thin film processing to the applicability to SOFCs is discussed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.8
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• pp.71-77
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• 2002

We consider the simultaneous slewing and vibration suppression control problem of an idealized structural model which has a rigid hub with two cantilevered flexible appendages and finite tip masses. The finite clement method(FEM) is used to obtain linear finite dimensional equations of motion for the model. In the linear quadratic regulator(LQR) problem, a simple method is introduced to provide a physically meaningful performance index for space structure models. This method gives us a mathematically minor but physically important modification of the usual energy type performance index. A numerical procedure to solve a time-variant LQR problem with inequality control constraints is presented using the method of particular solutions.

• Journal of Dairy Science and Biotechnology
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• v.33 no.4
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• pp.253-262
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• 2015

The authentication and implications of misleading labeling in milk and dairy products is important to protect against cheating consumers from adulteration and to alert sensitive consumers to any undeclared potential allergens. This need to support milk and dairy products labeling has led to the development of specific analytical techniques for the analysis of milk and dairy products ingredients. Recently, several methods based on polymerase chain reaction (PCR), including restriction fragment length polymorphism (PCR-RFLP), multiplex PCR, species-specific PCR, and real-time PCR, have been proposed as useful means for identifying species of origin in milk and dairy products, as well as quantifying and detecting any adulteration. These methods have particular advantages owing to their high specificity and sensitivity, as well as rapid processing time. In this review, we provide an updated and extensive overview of the PCR-based methods used for milk and dairy products authentication with a particular focus on the application of PCR methods to detect adulteration.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.11 no.5
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• pp.93-102
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• 1997

In order tl get Maaterial requirements for the Improviment of erliability of Insulatint materials for power cables, partial discharge characteristics of Polyethylenes were measured by an ultrasonic techjique and Measured signals were processed to cbtain the paraceters useful for thr quantification of partial discharge characteristics of polyethylenes. This technique was applied to obtain material requirements for the development of improved insulating materials for power cables,As a result, it was found that partial discharging activities in polyethylenes were suppressed considerably when p proper amount of acrylic acid, 0.003[wt %]in this particular case, is grafted on polyethylene chains.It can be concludid from the present study that partial discharging actibities in polyethylenes could be suppressed by the modification of polyethylene with proper chemical components, acrilic acid in this particular study.

• The Journal of the Korea Contents Association
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• v.11 no.12
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• pp.597-610
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• 2011

In database application developments, data coexists in memory and disk spaces. To manipulate the memory data, the general programing languages are used and to manipulate the disk data, SQL is used. In particular, the procedural languages for the memory manipulation are difficult to create and manage than declarative languages such as SQL. Thus, this paper shows that a particular structure of memory data, tree structured, can be manipulated by SQL. Most of all, the model data of the user interfaces can be represented by a tree structure and thus, it can be processed by SQL except non set computations. The non set computations could be done by helper classes. The SQL memory data manipulation is more suited to the database application developments which have few complex computations.

• Computers and Concrete
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• v.12 no.6
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• pp.755-774
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• 2013

Considering the well known environmental issues of cement manufacturing (direct and indirect levels of $CO_2$ emissions), clinker replacement by supplementary cementing materials (SCM) can be a very promising first step in reducing considerably the associated emissions. However, such a reduction is possible up to a particular level of SCM utilization, influenced by the rate of its pozzolanic reaction. In this study a (4-step) structured methodology is proposed in order to be able to further adjust the concrete mix design of a particular SCM, in achieving additional reduction of the associated levels of $CO_2$ emissions and being at the same time accepted from a derived concrete strength and service life point of view. On this note, the aim of this study is twofold. To evaluate the environmental contribution of each concrete component and to provide the best possible mix design configuration, balanced between the principles of sustainability (low environmental cost) and durability (accepted concrete strength and service life ). It is shown that such a balance can be achieved, by utilising SCM by-products in the concrete mix, reducing in this way the fixed environmental emissions without compromising the long-term safety and durability of the structure.

• Journal of Biomedical Engineering Research
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• v.28 no.4
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• pp.449-454
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• 2007

An electrohydraulic (EH) pump-driven closed-loop blood pressure regulatory system was developed based on flow-mediated vascular occlusion using the vascular occlusive cuff technique. It is very useful for investigating blood pressure-dependant physiological variability, in particular, that could identify the principal mediators of renal autoregulation, such as tubuloglomerular feedback (TGF) and myogenic (MYO), during blood pressure regulation. To address this issue, renal perfusion pressure (RPP) should be well regulated under various experimental conditions. In this paper, we designed a new EH pump-driven RPP regulatory system capable of implementing precise and rapid RPP regulation. A closed-loop servo-controlwas developed with an optimal proportional plus integral (PI) compensation using the dynamic feedback RPP signal from animals. An in vivo performance was evaluated in terms of flow-mediated RPP occlusion, maintenance, and release responses. Step change to 80 mmHg reference from normal RPP revealed steady state error of ${\pm}3%$ during the RPP regulatory period after PI action. We obtained rapid RPP release time of approximately 300 ms. It is concluded that the proposed EH RPP regulatory system could be utilized in in vivo performance to study various pressure-flow relationships in diverse fields of physiology, and in particular, in renal autoregulation mechanisms.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.6
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• pp.2193-2197
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• 2015

Cervical cancer, mostly progressing from cervical intraepithelial neoplasia, is a major cause of morbidity and mortality in Chinese women. This is largely due to high prevalence of high-risk human papillomaviruses (hr-HPVs) in the population. The prevalence of hr-HPV DNA in women and in cervical lesions women ranged from 9.9% to 17.% and from 50.5% to 70.9% in different regions of China, respectively. The most common genotypes somewhat differ between regions throughout the country and from those in many other countries. This may be a challenge to cervical cancer screening and prevention in China. Combined detection of particular HPV genotypes should be recommended in all geographical regions in China and greater attention must be paid to specific hr-HPV types during cervical cancer screening and follow-up of cervical lesions. Besides, vaccination for prevention of cervical cancer by particular HPV genotypes, has not been introduced to China so far. Updated knowledge on prevalent HPV genotypes should be provided to public health organizations to help with the development of more effective HPV vaccines, which can protect Chinese women against HPV types prevalent in local China and thus have a substantial impact on the cervical cancer burden.

• Environmental Engineering Research
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• v.25 no.2
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• pp.197-204
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• 2020

A number of different nanoscale zero-valent iron (nZVI) materials have been prepared and compared depending on the desired properties for the particular application, but different physicochemical properties of this prepared nZVI make it difficult to universally compare and standardize them to the same scale. In this study, we aimed to demonstrate a simple microplate-based colorimetric assay using 4-chlorophenol as an indicator with respect to the remediation of real treatment targets, such as trichloroethylene (TCE), 1,1,1-trichloroethane (TCA), and atrazine. Effect of nickel contents on 4-chlorophenol reduction was successfully investigated by the miniaturized colorimetric assay. In the same manner, the effect of nickel contents on dehalogenation of TCE, TCA, and atrazine was investigated and the pseudo-first-order kinetic constants were compared with the results for 4-chlorophenol. The similar pattern could be observed between 4-chlorophenol reduction obtained by colorimetric assay and TCE, TCA, atrazine reduction obtained by a traditional chromatographic method. The reaction kinetics does not match perfectly, but the degree of reaction can be estimated. Therefore, the colorimetric assay can be a useful and simple screening tool to determine nZVI reactivity toward halogenated organics before it is applied to a particular remediation site.