• Journal of the Society of Disaster Information
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• v.13 no.4
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• pp.483-490
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• 2017

Recently, the demand for industrial and residental land are increasing with economic growth, but it is difficult to obtain the area for development with good ground condition. Various kinds of vertical drain technologies such as sand drain, sand compaction pile, packed drain, PVD are commercially available to improve the soft ground. Discharge capacity is the important factor of vertical drains. However, under field conditions, discharge capacity is changed with various reasons, such as soil condition, overburden pressure, and so on. In this paper, the experimental study was carried out to estimate the discharge capacity of four different types of PBD, PBD for double core PBD, deep type PBD, X type PBD, general type PBD. Characteristics of the discharge capacity for the surcharge load and hydraulic gradient were analysed. The double core PBD was excellent for discharge capacity in this study.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.719-720
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• 2007

Korea, for the first time in the world, constructed 765 kV double circuits transmission lines, which has 3 phases and 6 bundles with vertical arrangement using steel pipes in 1998. Also in 2002, we developed 765kV outdoor full GIS substation with self-developed technology. KEPCO accumulated a wealth of technologies for 765kV system construction and operation, and are listed 5th in technology field in the world. With this advanced technologies, we are developing oversea business. We started with a projects, 'Development Study on the Power System Network Analysis in Myanmar' in 2001, and continued the project to transmission design, consulting for transmission technology including the education of foreign trainees in south-east and middle east asia. Currently, 12 overseas businesses including 330kV transmission system consulting in Ghana, are in progress. In 2007, beginning with 750 kV transmission consulting in China, we are operating ATT(Advanced Transmission Technology) training program, which educate engineers of government and utilities company from China, Myanmar, Cambodia, Laos and Cambodia. However, for the successful development study on the power system, design of the power system and the training service, it is essential to standardize load design criteria in consideration of temperature, wind speed, air pressure and density, etc. of the other countries. Therefore, in this paper, standardized load design criteria for Cambodia, Laos, Myanmar is explained.

• Journal of the Korean Society of Safety
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• v.15 no.3
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• pp.66-70
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• 2000

In order to cope with environmental problems caused by harmful gases emitted from various industrial sources, a new technology which employs discharge plasma formed in ordinary atmospheric pressure has been intensively investigated in many industrialized nations. Although a plenty of useful outcomes and suggestions have been made public by scientists in this field, few commercial products which effectively decompose pollutant gases have appeared as yet. This is partly because that the energy efficiency of a most effective plasma reactor has not reached a satisfactory level in comparison with those of devices using conventional technologies. In an attempt to solve the problem mentioned above, we noticed to combine heterogeneous electrical discharges. This concepts is based on that each plasma reactor has its specific spatial region in which chemical reaction are active and by electrically affected with another reactor of different type, the activated region would increase - which may lead to cutting down the energy consumption. To prove this concept experimentally, two different discharge equipments, a plane ceramic-based surface discharge electrode and a corona electrode with tungsten needle may, are selected and combined to fabricate a hybrid plasma reactor. The results are summarized as follows; (1) Ozone concentration generated in the plasma region drastically increases when the positive corona discharge is added to the surface discharge. The rate of increase of ozone depends on the frequency of the surface discharge. The negative corona, however, does not contribute to the improvement of the ozone generation. (2) NO(nitrogen monoxide) decomposition rate also improves by simultaneously applying the surface and the positive corona discharges. The effect of the corona superposition is more evident when the level of the surface discharge is moderate. (3) By adjusting the corona level, the net energy efficiency during NO decomposition improves in comparison with the simple surface discharge reactor.

• Journal of The Korea Institute of Healthcare Architecture
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• v.26 no.1
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• pp.73-84
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• 2020

Purpose: Though Korean healthcare services have been upgraded, infection and fire had been broken out in general hospitals. And higher concerns about quality assessment made it to clinical laboratory design guideline studies. So, this study investigates the facilities, equipment and personnel of laboratory medicine focusing on more than five hundred fifty bed hospital, and contributes to make guidelines for safety and efficiency in lab. Methods: Questionnaires to supervisor technologist and field surveys to medical laboratories in korean hospitals have been conducted for the data collection. 16 answers have been analysed statistically by MS Excel program. Results: Most of the sample tests such as hematology, clinical chemistry, immunology, transfusion, urinalysis, microbiology and molecular diagnosis are performed by more than 80% in large sized general hospital laboratory. In the test methods, automatic analyzers are used up to 80%, total laboratory automation up to 43% in clinical chemistry and immunology, and manual tests in all sorts of the test. There are placed in single lab or two and three labs above the ground, which are all in semi-open lab. There is some correlation with the number of specimens and the number of lab people depending on the number of hospital beds. Laboratory environment shows that work distance is good, but evacuation path width, visibility, separation of staff area from automatic analyzer, and equipment installations are needed to have more spaces and gears. Most of the infection controls are equipped with mechanical ventilation, air-conditioning, washbasin and wastewater separation, BSC installation and negative pressure lab room. Implications: Although the laboratory space area is calculated considering the number of hospital beds, type of tests and number of staff, hospital's expertise and the samples numbers per year should be taken into account in the planning of the hospital.

• Progress in Superconductivity
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• v.14 no.1
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• pp.30-33
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• 2012

We have grown $MgB_2$ superconducting thin films on the SiC buffer layers by means of hybrid physical-chemical vapor deposition (HPCVD) technique. Prior to that, SiC was first deposited on $Al_2O_3$ substrates at various temperatures from room temperature to $600^{\circ}C$ by using the pulsed laser deposition (PLD) method in a vacuum atmosphere of ${\sim}10^{-6}$ Torr pressure. All samples showed a high transition temperature of ~40 K. The grain boundaries of $MgB_2$ samples with SiC layer are greater in amount, compare to that of the pure $MgB_2$ samples. $MgB_2$ with SiC buffer layer samples show interesting change in the critical current density ($J_c$) values. Generally, at both 5 K and 20 K measurements, at lower magnetic field, all $MgB_2$ films deposited on SiC buffer layers have low $J_c$ values, but when they reach higher magnetic fields of nearly 3.5 Tesla, $J_c$ values are enhanced. $MgB_2$ film with SiC grown at $600^{\circ}C$ has the highest $J_c$ enhancement at higher magnetic fields, while all SiC buffer layer samples exhibit higher $J_c$ values than that of the pure $MgB_2$ films. A change in the grain boundary morphologies of $MgB_2$ films due to SiC buffer layer seems to be responsible for $J_c$ enhancements at high magnetic fields.

• Journal of Chest Surgery
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• v.21 no.4
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• pp.672-680
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• 1988

Munro is generally considered the first person to have demonstrated, in 1888, in an infant cadaver, the feasibility of dissection and ligation of a persistently patent ductus arteriosus. In august, 1938, Robert Gross reported first successful division and suture of the patent ductus of 7 year old girl. Interruption of a ductus is one of the most satisfactory and curative operations in the field of surgery for congenital heart disease. Seventy-eight consecutive cases of closure of patent ductus arteriosus were operated from June 1980 to June 1988 in the department of thoracic and cardiovascular surgery in Maryknoll Hospital. Retrospective clinical analysis of the patients were 1. There were 24 males, 54 females. 2. The age range of the patients were from 7 months to 32 years with the mean age 9.8 years. 3. Chief complaints of the patients were frequent URI[70.5%], dyspnea on exertion[36.9%], palpitation[10.3%], but 15 patients[19.2%] had no subjective symptoms. 4. Continuous machinery murmur could be heard at the 2nd or 3rd intercostal space on the left sternal border in 66 patients[84.6%]. The other 12 patients made systolic murmur. 5. Radiographic findings of the Chest P-A were cardiac enlargement in 55 patients[70%], enlargement of pulmonary conus and/or increasing density of pulmonary vascularity in 68 patients[87%]. 6. Electrocardiographic findings of the patients were within normal limit in 23 patients[36%], LVH in 38 patients[48.7%], RVH in 7 patients[9%], biventricular hypertrophy in 5 patients[6%]. 7. Cardiac catheterization performed in 62 patients. Mean Qp/Qs=2.5, mean pulmonary arterial pressure=45 mmHg. 8. 73 patients were operated through left posterolateral thoracotomy: Closure of the ductus by ligation in 64 cases, division with suture in 6 cases, and division with aortopatch in 3 cases. Ligation through median sternotomy under cardiopulmonary bypass were 5 cases. 9. There was no death associated with operation, but one case was experienced with intraoperative tearing of ductus resulting in massive bleeding. The other complications were transient hoarseness in 2 patients, chylothorax in 2 patients.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.358-358
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• 2010

Ion beam bombardment at low energy forms nanosize patterns such as ripples, dots or wrinkles on the surface of polymers in ambient temperature and pressure. It has been known that the ion beam can alter the polymer surface that induces skins stiffer or the density higher by higher compressive stress or strain energies associated with chain scissions and crosslinks of the polymer. Atomic scale structure evolution in polymers is essential to understand a stress generation mechanism during the ion beam bombardment, which governs the nanoscale surface structure evolution. In this work, Molecular Dynamics (MD) simulations are employed to characterize the phenomenon occurred in bombardment between the ion beam and polymers that forms nanosize patterns. We investigate the structure evolution of Low Density Polyethylene (LDPE) at 300 K as the polymer is bombarded with Argon ions having various kinetic energies ranging from 100 eV to 1 KeV with 50 eV intervals having the fluence of $1.45\;{\times}\;1014 #/cm2$. These simulations use the Reactive Force Field (ReaxFF), which can mimic chemical covalent bonds and includes van der Waals potentials for describing the intermolecular interactions. The results show the details of the structural evolution of LDPE by the low energy Ar ion bombardment. Analyses through kinetic and potential energy, number of crosslinks and chain scissions, level of local densification and motions of atoms support that the residual strain energies on the surface is strongly associated with the number of crosslinks or scissored chains. Also, we could find an optimal Ar ion beam energy to make crosslinks well.

• Journal of Welding and Joining
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• v.23 no.5
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• pp.37-42
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• 2005

The non-destructive Inspection of the fillet weldment has difficulties due to its geometrical complexity and uneasy access. The surface shear horizontal wave (SH-wave), however, has been successfully applied to the detection of cracks on the surface and sub-surface of the filet weldment heel part. The conventional ultrasonic inspection using the surface SH-wave is usually a contact method using piezoelectric transducer. Thus, it is not suitable for a field application because the reliability and repeatability of inspection are significantly affected by test conditions such as couplant, contact pressure and pre-process. In order to overcome this problem, a non-contact SH-wave inspection method using EMAT is propose. The experimental results with this non-contact method are compared with those with a conventional ultrasonic method in fillet weldment with slit type defects. It is shown that the non-contact inspection technique requires simple procedure and less time in the fillet weldment inspection.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.1
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• pp.77-82
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• 2013

A cyclone separator has been widely used in various industrial processes for removing fine particulate matter because it is easy to fabricate, cost effective, and adaptable to extremely harsh conditions. However, owing to the complex flow field in cyclones, a complete understanding of the detailed mechanisms of particulate removal has not yet been gained. In this study, a theoretical analysis was performed for calculating the collection efficiency and cut-off size in cyclones by taking into account the effects of geometrical and flow parameters. The collection efficiency and cut-off size values predicted by the theoretical model showed good agreement with experimental measurements for particles with a diameter of $0.5-30{\mu}m$. It was also revealed that the surface friction, along with the flow and geometrical parameters, has a significant effect on the cyclone performance.

• Journal of the Korean Society for Nondestructive Testing
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• v.32 no.5
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• pp.545-550
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• 2012

Steam generator is one of the major components of nuclear power plant and steam generator tubes are the pressure boundary between primary and secondary side, which makes them critical for nuclear safety. As the operating time of nuclear power plant increases, not only damage mechanisms but also scaled deposits on steam generator tubes are known to be problematic causing tube support flow hole blockage and heat fouling. The ability to assess the extent and location of scaled deposits on tubes became essential for management and maintenance of steam generator and eddy current bobbin data can be utilized to measure thickness of scale on tubes. In this paper, tube reference standards with various thickness of scaled deposit has been set up to provide information about the overall deposit condition of steam generator tubes, providing essential tool for steam generator management and maintenance to predict and prevent future damages. Also, methodology to automatically measure scale thickness on tubes has been developed and applied to field data to estimate overall scale amount.