• 한국초전도학회:학술대회논문집
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• v.16
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• pp.55-55
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• 2006

• Proceedings of the Materials Research Society of Korea Conference
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• 1998.08a
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• pp.109.1-109
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• 1998

• Bulletin of the Korean Chemical Society
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• v.20 no.1
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• pp.7-15
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• 1999

The present paper is a review of the current studies of quantum beats in recombination of spin-correlated radical pairs in solutions as well as of future applications of quantum beats technique for studying these pairs. Examples are given of the use of this method for determining the hfi constants and relaxation times of short-lived radical ions, for finding the rate constants of the reactions of alkane radical cations and for estimating a fraction of singlet-correlated pairs in the pairs in the tracks of ionizing particles. The potentialities of this method, its advantages and limitations are discussed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.05b
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• pp.127-129
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• 2005

We investigated the fault current limiting characteristics according to the various facilities in power system. Power systems are becoming larger and larger for meeting electric power demand. Therefore, the over-currents resulting from contingencies such as short circuits are increasing higher, which causes the ratings of circuit breakers(CBs) to increase. Upgrading or replacement of CBs is not difficult from the technical and economical point of view. Bus split is being adopted into a part of 154 kV power systems, but it has adverse effects such as overload to neighboring power systems, increased voltage fluctuation, and decreased power system stability. For 345 kV power systems, the bus split measure is not feasible and dc reactors are being suggested. The superconducting fault current limiter is a protection gear of new concept that limits fault current automatically in a few milliseconds. It can also provide the effect of CB capacity increase, relaxation of power machine criteria, enhancement in power system reliability, and flexible power system operation.

• Journal of Oriental Neuropsychiatry
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• v.27 no.4
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• pp.235-248
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• 2016

Objectives: The aim of this review was to investigate whether evidence of complementary and alternative medicine (CAM) was reflected in clinical practice guidelines (CPGs) for insomnia based on relevant clinical trials. Methods: We conducted a systematic search on domestic and international CPG databases and medical databases. In addition, we conducted manual searches of relevant articles. Three authors independently searched and selected relevant studies; any disagreement was resolved by discussion. We extracted and analyzed the following data: published language, country, development group, participants, interventions, presence or absence of recommendations for CAM, level of evidence, grade of recommendation for CAM, and methods of development. Results: We identified 8,241 records from domestic and international databases, and 22 CPGs were included. Eleven of the 22 CPGs mentioned CAM interventions including herbal medicine, relaxation, acupuncture moxibustion, Tai Chi, meditation, hypnosis, biofeedback, Tuina, and external herbal medicine. However, most of the CPGs indicated 'no recommendation' or 'weak recommendation' for CAM interventions. Only Valeriana dageletiana Nakai and relaxation were considered to have experimental evidence. Valeriana dageletiana Nakai was recommended for improvement of sleep latency, sleep maintenance, total sleeping time, and sleep cycle. Relaxation was recommended as effective intervention for relieving physical and psychological arousal. Conclusions: Despite systematic reviews and randomized controlled trials on CAM for insomnia, most of the CPGs for insomnia did not reflect the evidence obtained. Further CPGs for insomnia should be developed by considering the current advanced studies in the field of CAM.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1A
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• pp.67-74
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• 2006

The use of steel plates has been greatly increased in bridge construction, particularly for long-span bridges. For connections of those steel plates in the field, application of high-tension bold, such as M30, is highly demanded. However, the current steel construction specifications in Korea do not provide information for large-sized bolt connections. In order to evaluate the applicability of the large-sized high-tension bolt, this study experimentally investigates relaxation and slip behavior of M30 bolts with varying bolt size and plate thickness. In addition, internal compressive stress was computed using FEM analysis. The analyzed results were compared with the stress distribution measured from strain gages attached on bolts and bolt holes. From the study presented herein, the M30 high-tension bolts are anticipated to be successfully used with the relaxation less than 10% and the slip coefficient satisfying the specified limit.

• Journal of Biosystems Engineering
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• v.28 no.2
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• pp.157-166
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• 2003

The purpose of this study is to characterize the internal physical properties of fresh Korean ginsengs (Panax ginseng C.A. Meyer) through a magnetic resonance imaging (MRI) technique. Current external visual inspection cannot determine internal quality of ginsengs successfully. Relaxation time constants, T$_1$ and T$_2$*, were obtained from a series of MR images. Calculated Ti values were varied with different physiological states of ginseng tissues. Internal imaging information was obtained nondestructively from fresh ginsengs. One- and two-dimensional image analyses were performed. One-dimensional image analysis showed a potential of age identification of ginsengs rapidly. Internal quality of normal and abnormal ginsengs was evaluated using two-dimensional MR images. Various types of internal defects such as internal cavity and rotten spot were visualized clearly. The MRI technique had a feasibility to detect internal defects of fresh ginsengs effectively.

• KIEAE Journal
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• v.15 no.2
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• pp.37-43
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• 2015

Purpose: It is crucially important that indoor luminous conditions of built environments be carefully studied so as to promote comfort and occupants' well-being. Method: The current study therefore focuses on the lit aspect of an enclosed space considered to be a resting room ($4.5m{\times}6.32m{\times}2.5m$). Particularly, on the effect that light levels and light color temperatures have on the physiological and psychological responses of resting occupants. To do so, a questionnaire survey was carried out on 50 subjects. The independent variables for the experiment included 9 different luminous environment conditions setup using 3 different levels of illuminance (50 lx, 150 lx, 300 lx) and 3 different color temperatures (2000 K, 3800 K, 5600 K). A questionnaire was utilized in determining which conditions were preferred by occupants. Result: As it turns out, indoor luminous environment designed for relaxation purposes should display luminance levels of at least 150 lx and 3800 K of color temperature in order to provide a visually comfortable environment suitable for the occupant's relaxation while at the same time promoting the psychological and HRV well-being of resting occupants.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.295-296
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• 2006

We developed wire frame drive unit based on SMA for the 3D Shape display. Our basic concept is wire frame combination connected with a chain form which can create various shapes and it compared with pin array mechanism which is not able to display mushroom shape. It imitates antagonist mechanism of human musculoskeletal system. we create similar motion using repair-relaxation mechanism and locking mechanism by SMA. Therefore, in this paper, we propose SMA control solution for actuating repair-relaxation mechanism and locking mechanism. In our control system. we use optical sensor and quantitative angle between wire frames for closed loop control. And we supply amplified current for SMA by circuit composed of transistor and apply PWM signal to circuit for efficient control. So, wire frame drive unit enable diversity angle control based on sensor data. And then combination of wire frame drive units will create various objects.

• Journal of Ginseng Research
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• v.32 no.2
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• pp.89-98
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• 2008

There are increasing evidences in the literatures on the potential role of ginsenosides in treating cardiovascular diseases. In this article, current information about ginsenosides-mediated vascular relaxation are reviewed. From the published studies using isolated organs, cell culture systems and animal models, ginsenosides are shown to relax blood vessels and improve blood flow through diverse mechanisms, including nitric oxide release by activating eNOS phosphorylation via PI3K/Akt and/or ERK1/2 pathways in endothelial cells, induction of inducible nitric oxide synthase through activation of NF-${\kappa}$B, reducing the intracelluar Ca$^{2+}$ levels by activating Ca$^{2+}$-activated K$^{+}$ channels in vascular smooth muscle cells and reducing platelet aggregation by decreasing thromboxane A$_2$ formation and intracelluar Ca$^{2+}$in platelets. In addition, the relevant clinical trials regarding the effects of ginsenosides on the cardiovascular disease are summarized, particulary focusing on managing hypertension and improving thrombotic disorders. Finally, antagonistic effects of ginsenosides on the prostaglandin H$_2$ receptor and scavenging effects on the generation of oxygen-derived free radicals in spontaneously hypertensive rats (SHR) are discussed.