• Proceedings of the KSR Conference
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.706-712
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• 2006

The present volume should address the unique method of deterioration analysis tailorly applicable to the study of traction motor, not existent maintenance works system with the time period standard, such as regular inspection works, maintenance works, selection for the repair works. The present volume has executed various field experiments in this method, should propose the procedures and baselines for anticipating the life expansion of traction motor and building precautional maintenance system for it, on the basis of these field experiments. The improvement scheme of traction motor maintenance system in the present volume should be to keep the out-of-order rate from unexpectedly soaring and make the cost-reduction effect through better maintenance work method.

• Proceedings of the Korean Geotechical Society Conference
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• 한국지반공학회 2002년도 봄 학술발표회 논문집
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• pp.479-482
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• 2002

The purpose of this paper is to present and discuss some of evaporation and desiccation observed in field experiments. Surface desiccation of dredged material is basically changed by evaporation characteristics which is controlled by weather and ploughing interval, etc. This study shows that ploughing interval is important factors in desiccation of dredged soft clay. A series of field experiments with variation of ploughing interval were carried out to get evaporation effiency and strength increase. In this study, it is proposed that ploughing technique on the total surface area expedites surface desiccation efficiency. Desiccation efficiency is improved when ploughing technique is applied on the surface area.

• Journal of the Korean Society of Safety
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• 제10권2호
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• pp.72-76
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• 1995

An electrostatic passive neutralizer without HV power source has been used widely to reduce charges on insulators such as running plastic films, papers and cloths, but its elimination characteristics and safely have been hardly investigated in detail. Especially, an operation of the passive neutralizer depends primarily on the charged insulator and the elimination ability does not depend on only the neutralizer, because an electrostatic elimination is caused by corona discharges occurring between the passive neutralizer and charged insulator. From a reason described above, the purpose of this study is to examine experimentally the elimination ability of the passive neutralizer. Experiments were made on the corona discharges between the passive neutralizer and charged insulator running at high velocity in practical field to make clear the setting condition of the passive neutralizer for operating effectively and safely. Results obtained from field experiments are presented in this paper.

• The Korean Journal of Applied Statistics
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• 제11권2호
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• pp.423-433
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• 1998

In agricultural field experiments, the completely randomized block design is often used for the analysis of variety trials. An important assumption is that every experimental unit in each block has the some fertility. But, in most agricultural field experiments there often exists a systematic heterogeneity in fertility among the experimental units. To account for the heterogeneity, we propose to use the hierarchical generalized linear models. We compare our analysis of the data from Scottish Agricultural colleges list with that using Markov chain Monte Carlo method.

• Transactions of Materials Processing
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• 제21권4호
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• pp.265-270
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• 2012

In this study, a process design method for the multi-pass shape drawing is proposed with consideration of the drawing stress. First, the shape drawing load was calculated to evaluate the shape drawing stress, and the intermediate die shape was determined by using an electric field analysis and the average reduction ratio. In order to evaluate whether material yielding occurs at the die exit, the drawing stress was determined by using the calculated shape drawing load. Finally, FE-analysis and shape drawing experiments were conducted to validate the design of the multi-pass shape drawing process. From the results of the FE-analysis and shape drawing experiments, it was possible to produce a sound shape drawn product with the designed process. The dimensional tolerances of the product were within the allowable tolerances.

• Bulletin of the Korean Chemical Society
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• 제27권3호
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• pp.413-418
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• 2006

Sodium hyaluronate (NaHA), water soluble polymer having ultra-high molecular weight, is characterized by using on-line frit inlet asymmetrical flow field-flow fractionation (FI-AFlFFF) and multiangle light scattering (MALS). This study demonstrates the capability of power programming FI-AFlFFF for the separation of NaHA and the applicability of FI-AFlFFF with MALS for the characterization of molecular weight distribution and their structural information. Since sample injection and relaxation in FI-AFlFFF are achieved by using hydrodynamic relaxation, separation of high molecular weight polymers can be achieved smoothly without halting the separation flow. Experiments are carried out with the two different NaHA products (a raw NaHA sample and a thermally degraded NaHA product) and molecular weight distribution and conformations in solution are determined. Influence of sample filtration on the change of molecular weight distribution is also discussed.

• Progress in Superconductivity and Cryogenics
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• 제2권1호
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• pp.31-34
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• 2000

this paper deals with the initial magnetic field decay for a large scale superconducting magnet e.g. NMR/MRI magnet. The high resolution image can not be obained during the periods of the initial field decay. It is known that all superconducting materials have the property of diamagnetism. This diamagnetism is usually explained with the concept of screening current. We assumed that the existence of the screening currebt. we assumed that the existence of the screening current makes the current distribution in the superconducting wire non-uniform. And the initial magnetic field decay is caused steady current state in the view of its pattern. The initial magnetic field decay is caused by the change of the current distribution between the energizing state and persistent current mode. in this paper the theoretical analysis for the current distributions has been introduced for each state. The experiments have been carried out to verify transport currents in order to veperiments, it small at the higher transport current.

• Journal of the Korean housing association
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• 제14권6호
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• pp.79-86
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• 2003

People grow up and build up most of their character through living in dwelling space and have relax and refresh at home. Creating healthy dwelling space is being considered very important in architectural planning and design for providing comfortable living environment and improving quality of life. Many research papers and experiments indicates that the geomagnetic field affects the people and living organism. Therefore, it is necessary to investigate the geomagnetic field and people's response in dwelling space. In this study the Importance and Effect of Geomagnetic Field in dwelling space are studied through literature survey of related science field.

• Progress in Superconductivity and Cryogenics
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• 제20권2호
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• pp.11-15
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• 2018

In this study, a cancer treatment by accumulating and aggregating ferromagnetic particles in newborn blood vessels was examined. It is necessary for this treatment to control dispersion-aggregation property of ferromagnetic particles. Ferromagnetic particles required in this method disperse at low magnetic field, aggregate at high magnetic field and maintain the aggregation even after removal of the magnetic field. In order to control the dispersion-aggregation property, the surface of magnetite particles was modified with higher fatty acids having different lengths. As a result, we succeeded to prepare propionic acid-modified magnetite particles that form irreversible aggregation by magnetic field. The model experiments simulating newborn blood vessels showed that these particles can block the flow by the magnetic field, and the blockage was maintained after removal of the magnetic field.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 한국조명전기설비학회 2004년도 춘계학술대회 논문집
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• pp.559-564
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• 2004

This paper deals with the device for measuring the time-varying magnetic fields and induced voltages caused by lightning discharges. The two magnetic field measuring systems were designed and made. One consists of the loop-type magnetic field sensor with the active integrator operated by a differential amplifier. The other consists of the loop-type magnetic field sensor and Labview software. The loop-type magnetic field sensor detects the time derivative of the magnetic field being measured, and the signal detected is integrated by the Labview software. As a consequence, from the calibration experiments, the frequency bandwidth of the full measuring system ranges from 400 [Hz] to 1 (MHz) and the response sensitivity are 0.98 (mV/nT) and 22 (mV/nT) for the magnetic field sensor of 2 turns and 6 turns, respectively. Also, the results obtained by the two measuring devices well agreed with each other.