• Journal of Korean Medicine Rehabilitation
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• v.18 no.4
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• pp.121-133
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• 2008

Objectives : MENS was used for wound healing and pain relief using bioelectric property. There are many articles on in vivo and clinical research. This article reviews articles on MENS published for recent 10 years to consider effectiveness of MENS and other fields to applicate MENS. Articles were collected from MAR, 2008 to JUN, 2008. Methods : We searched Pubmed, KSI, KERIS, KMBASE, and National assembly library using "Microcurrent Electrical Neuromuscular Stimulation" and classified the articles into subsets of foreign, Korean and wound healing, pain, relief, and increasing the range of movement(ROM). Also we evaluated their values according to the Jadad scale. Results : A total of 18 articles (Foreign-9, Korean-9) reconfirmed that MENS reduces pain, increases wound healing, ROM, and strength of muscle. In addition, MENS has effect on stress-hormone and various pain like low back pain, acute lateral epicondylitis, and plantar fascitis. And there are various styles developed. However, there is no standard protocol so the user is usually in trouble at clinic. Conclusions : MENS may be have application to various pain diseases, and further studies analysing its effectiveness are needed.

• Structural Engineering and Mechanics
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• v.32 no.2
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• pp.251-267
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• 2009

Reinforced concrete (RC) structures consist of two different materials: concrete and steel bar. The stress transfer behaviour between the two materials through bond plays an important role in the load-carrying capacity of RC structures, especially when they subject to lateral load such as blast and seismic load. Therefore, bond and slip between concrete and reinforcement bar will affect the response of RC structures under such loads. However, in most numerical analyses of blast-induced structural responses, the perfect bond between concrete and steel bar is often assumed. The main reason is that it is very difficult to model bond slip in the commercial finite element software, especially in hydrodynamic codes. In the present study, a one-dimensional slide line contact model in LS-DYNA for modeling sliding of rebar along a string of concrete nodes is creatively used to model the bond slip between concrete and steel bars in RC structures. In order to model the bond slip accurately, a new approach to define the parameters of the one-dimensional slide line model from common pullout test data is proposed. Reliability and accuracy of the proposed approach and the one-dimensional slide line in modelling the bond slip between concrete and steel bar are demonstrated through comparison of numerical results and experimental data. A case study is then carried out to investigate the bond slip effect on numerical analysis of blast-induced responses of a RC column. Parametric studies are also conducted to investigate the effect of bond shear modulus, maximum elastic slip strain, and damage curve exponential coefficient on blast-induced response of RC columns. Finally, recommendations are given for modelling the bond slip in numerical analysis of blast-induced responses of RC columns.

• Journal of the Society of Naval Architects of Korea
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• v.55 no.5
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• pp.438-447
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• 2018

For a fixed jacket type offshore structure directly supported by the seabed, the structural behavior of offshore structure depends on the soil properties. Soil properties affect on the stiffness of the piles and the boundary condition in the structural analysis. The structural analysis is performed using PSI (Pile-Soil Interaction) suggested in the code and design rule. PSI analysis of the jacket structure is carried out after various soil types are selected according to the soil properties like internal friction angle, undrained shear strength, unit weight and so on. Three types of soil are selected by varying strength for a clay and sand, respectively. The structural analysis of the jacket structure is performed using these soils. The results about axial and lateral reaction force and the stress and displacement on the structure are compared. As a results, the structural response is smaller as the soil becomes more stiff. In conclusion, it is confirmed that the structural response of fixed jacket type offshore platform supported by seabed is sensitive to the change of soil properties.

• Journal of Dental Rehabilitation and Applied Science
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• v.32 no.4
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• pp.322-329
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• 2016

Reconstruction of the maxillectomy with an obturator is to restore masticatory, swallowing, phonetic and esthetic problems. Stress created by lateral forces is minimized by the proper selection of an occlusal scheme, elimination of premature occlusal contacts, and wide distribution of supporting area. It should be considered that properly designed retainers reduce the stresses transmitted to the abutment while the obturator is in function. The following clinical report presents palatal obturator treatment with implant assisted removable partial denture (IARPD) design that restores normal function and esthetics in patients who experienced maxillectomy and dental implant failure.

• Geotechnical Engineering
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• v.8 no.3
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• pp.23-36
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• 1992

The flat dilatometer(DMT) has been practically used as an in-situ test equipment. It is a simple, rapid and cost-effective tool to characterize the in-situ stress-strain-strength properties of various types of ground materials. However, the results of flat DMT should be validated with considerable data with respect to the known reference values for a specific site. In this study, the applicability of existing relationships which were established for other local deposits is verified by performing the tests in several clay deposits. To compare with the DMT results, field vane tests and cone penetration tests were also carried out in the same field as reference tests, and unconsolidated undrained tests, oedometer tests, and other fundamental material properties tests were conducted on the thin-walled tube samples in the laboratory. The results of the flat DMT combined with empirical correlations are used to estimate soil types, unit weights, coefficients of lateral earth pressure at rest, overconsolidation ratios, constrained moduli and undrained shear strengths of three clay local deposits. It was found that various geotechnical properties estimated from the flat DMT generally well agree with those from the reference tests.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.1
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• pp.103-111
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• 2011

This paper estimated the structural behavior of recycled aggregate concrete confined with spiral reinforcement. The main test parameter was designed to be the type of aggregates and the steel ratio of spirals. A total of 18 specimens were cast and tested in this study. All the specimens had a diameter of 150mm and a height of 300mm. The specimens can be divided into two groups, based on the type of coarse aggregate used. The ratio of spiral reinforcement was varied from 0 % to 1.75%. To measure the axial and lateral deformations of the specimens, a total of six linear variation displacement transducers (LVDTs) were installed at each specimen. Furthermore strain gauges were also attached to the steel spirals to obtain the strain of spiral reinforcements. From the experimental results, the structural performance of recycled aggregate concrete specimens confined by steel spirals was similar to that of natural aggregate concrete specimens regardless of the ratio of spiral reinforcement.

• Journal of Crop Science and Biotechnology
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• v.10 no.2
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• pp.57-63
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• 2007

Due to the strong influence of nitrogen(N) on plant productivity, a vast amount of N fertilizers is used to maximize crop yield. Over-use of N fertilizers leads to severe pollution of the environment, especially the aquatic ecosystem, as well as reducing farmer's income. Growing of N-efficient cultivars is an important prerequisite for integrated nutrient management strategies in both low- and high-input agriculture. Taking maize as a sample crop, this paper reviews the response of plants to low N stress, the physiological processes which may control N-use efficiency in low-N input conditions, and the genetic and molecular biological aspects of N-use efficiency. Since the harvest index(HI) of modern cultivars is quite high, further improvement of these cultivars to adapt to low N soils should aim to increase their capacity to accumulate N at low N levels. To achieve this goal, establishment and maintenance of a large root system during the growth period may be essential. To reduce the cost of N and carbon for root growth, a strong response of lateral root growth to nitrate-rich patches may be desired. Furthermore, a large proportion of N accumulated in roots at early growth stages should be remobilized for grain growth in the late filling stage to increase N-utilization efficiency. Some QTLs and genes related to maize yield as well as root traits have been identified. However, their significance in improving maize NUE at low N inputs in the field need to be elucidated.

• Journal of Korean Society of Steel Construction
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• v.19 no.5
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• pp.483-492
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• 2007

Pre-Engineering Building (PEB) system is one of the most economical structural systems. Tapered members can resist a maximum stress at a single location, whereas stresses of the rest of the members are considerably low. This results in appreciable savings both in terms of materials and construction costs. However, it was appreciated that special consideration would be required for certain aspects of this structural form. In particular, because of their slenderness, webs would buckle laterally and torsionally under the combined action of excessive axial, bending and shear forces. In this study, a total of four large-scale rafters with simple ends were tested. The main parameters were the width-thickness ratio of the web, the stiffener, and the flange brace. The purpose of this experiment is to evaluate the structural stability and to offer back-data on PEB design.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.124-124
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• 2010

Much interest has been focused on InGaN-based materials and their quantum structures due to their optoelectronics applications such as light emitting diode (LED) and photovoltaic devices, because of its high thermal conductivity, high optical efficiency, and direct wide band gap, in spite of their high density of threading dislocations. Build-in internal field-induced quantum-confined Stark effect in InGaN/GaN quantum well LED structures results in a spatial separation of electrons and holes, which leads to a reduction of radiative recombination rate. Therefore, many growth techniques have been developed by utilizing lateral over-growth mode or by inserting additional layers such as patterned layer and superlattices for reducing threading dislocations and internal fields. In this work, we investigated various characteristics of InGaN multiple quantum wells (MQWs) LED structures grown on selectively wet-etched porous (SWEP) GaN template layer and compared with those grown on non-porous GaN template layer over c-plane sapphire substrates. From the surface morphology measured by atomic force microscope, high resolution X-ray diffraction analysis, low temperature photoluminescence (PL) and PL excitation measurements, good structural and optical properties were observed on both LED structures. However, InGaN MQWs LED structures grown on SWEP GaN template layer show relatively low In composition, thin well width, and blue shift of PL spectra on MQW emission. These results were explained by rough surface of template layer, reduction of residual compressive stress, and less piezoelectric field on MQWs by utilizing SWEP GaN template layer. Better electrical properties were also observed for InGaN MQWs on SWEP GaN template layer, specially at reverse operating condition for I-V measurements.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.1
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• pp.133-140
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• 2010

Five strengthened columns and an unstrengthened column were tested under constant axial load and cyclic lateral loads to examine the seismic performance of the unbounded strengthening procedure using wire ropes and T-plates. Main variables considered were the presence of mortar cover for strengthening steel element and anchorage method of T-plate. Test results clearly showed that T-plates having a proper anchorage contribute to transfer of applied moment as well as enhancement of ductility of reinforced concrete columns. However, T-plate not anchored fully into a column base can seldom transfer the externally applied moment, though it highly improves the ductility of column. The presence of mortar cover for strengthening steel elements is significantly effective in enhancing the initial stiffness and flexural capacity of the strengthened columns, but has an adversely effect on enhancing the ductility. The ultimate moment strength predicted from the extended section laminae method in better agreement with test results compared with predictions obtained using stress black specified in ACI 318-05.