• Journal of the Korea Institute of Building Construction
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• v.24 no.1
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• pp.55-66
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• 2024

This research addresses the types and causes of defects in seismic retrofitting projects of school facilities, which, following the Gyeongju and Pohang earthquakes in September 2016 and November 2017 respectively, have been identified as having comparatively lower seismic resilience among public buildings. The incidence of seismic retrofitting has notably increased in the subsequent years, raising concerns about the potential for defects arising from these efforts. The government has committed to enhancing the seismic resilience of all public facilities by 2035, with a specific focus on completing upgrades for educational establishments by 2029. Although prior investigations have explored construction defects in school facilities, there exists a gap in research specifically targeting defects within seismic retrofitting processes. Thus, this study aims to catalog the defects associated with seismic retrofitting efforts and analyze their underlying causes to identify crucial management strategies for defect mitigation. Furthermore, by examining the interplay between defect types and their causative factors, the study seeks to pinpoint essential management practices that could preempt defects during the construction phase, ultimately aiding in the reduction of future maintenance expenditures.

• Clinical and Experimental Reproductive Medicine
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• v.19 no.1
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• pp.71-79
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• 1992

In vitro fertilization and embryo transfer (IVF & ET) is widely used for the males with subnormal or abnormal semen quality, as this was recommended in view of the relatively small numbers of spermatozoa required for fertilization and subsequent pregnancies could be obtained. The aim of this study is to know how the various functional parameters of spermatozoa in semen analysis affect the outcome IVF. This study was carried out between 1988-1989, with male factor patients selected on the basis of the semen quality. The selection criteria was based upon the mean values of concentration,% motility and % normal morphology from at least two semen analysis. There is a significant decrease in the fertilization and embryo transfer rates in the study group compared with control group (35.9% vs. 68% and 48.6% vs. 85.5% respectively), however, there was no significant difference in the pregnancy or delivery rates (19.6% vs. 21.4% and 60.0% vs. 62.5% respectively) per embryo transfer cycles. Fertilization rate is variously affected by the type and degree of sperm defect. No pregnancy was occurred in triple defect group and asthenoteratospermia group. There is no significant increase in the abortion rate in the male factor group. Improvement have to be made with the fertilization rate, as the pregnancy rate per OPU cycle in male factor group is still lower than that of normal group (9.5% vs. 18.3%). In conclusion, IVF can be used as a treatment for male factor infertility and the preparation of the semen sample can be modified to improve sperm recovery and obtain fertilization from abnormal semen samples.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.3 s.96
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• pp.145-153
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• 1999

This study has been performed to investigate the stress distribution around defects that behave as stress concentrators and fracture mechanical analysis for cracks initiatiating at stress concentrators. The stress distribution was analyzed using Finite Element Method and non dimensional stress intensity factor was determined by the mean stress method. In addition, stress interaction effects around defects and cracks were compared.

• Transactions of Materials Processing
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• v.1 no.1
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• pp.66-74
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• 1992

According to the variation of hydrostatic pressure on the central axis of deformable material, the V-shaped central bursting defect may be created in extrusion or drawing processes. The process factors which affect the generation of defects are semi-angle of die, reduction ratio of cross-sectional area, friction factor, material properties and so on. The combination of these factors can determine the possibility of defect creation and the shape of various round holes which have been created inside already. By the rigid plastic finite element method, this paper describes the observations of change in shape of round holes with process conditions such as semi-angle of die, reduction ratio of cross-sectional area and friction factor at the non-steady state of axisymmetrical extrusion process when the round hole is already existed inside the original billet. Also, the effects of process factors are investigated to prevent the possible defects.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.2 s.233
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• pp.284-292
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• 2005

Material flaws in the from of pre-existing defects can severely affect the crack initiation. Stress distribution and crack initiation life of engineering materials such as monolithic aluminum alloy and Al/Glass fiber laminate may be different according to the defect location. The aim of this study is to evaluate effects of relative location of defects around the circular hole in monolithic aluminum and Al/Glass fiber laminates under cyclic bending moment. Stress distribution and crack initiation behavior near a circular hole are considered. Results of Finite Element (FE) model indicated the features of different stress field due to the relative defects positions. Especially, the defects positions at ${\theta}=0^{\circ}\;and\;{\theta}=30^{\circ}$ was strongly effective in stress concentration factor ($K_t$) and crack initiation behavior.

• Journal of Trauma and Injury
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• v.33 no.1
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• pp.48-52
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• 2020

Composite skull defects in patients with severe head injuries are very challenging to manage. The dilemma when deciding whether to perform a definitive reconstruction is how long to wait for physiological recovery before an intervention complicates the situation. The inability of such patients to tolerate prolonged anesthetic exposure is a driving factor for performing the minimal intervention necessary to facilitate recovery. Herein, we present a case involving the successful immediate reconstructive treatment of a severely head-injured adolescent with a composite scalp defect secondary to trauma. A 14-year-old boy sustained a severe head injury from a motor vehicle accident with a composite scalp defect in the right fronto-parietal region. The frontal lobe was exposed, and the right eye was crushed and devitalized. The patient was deeply unconscious for 3 days, without any significant improvements before reconstructive surgery was proposed due to fear of possible meningitis resulting from the exposure of brain structures. We successfully managed the patient with a fronto-parieto-occipital flap, after which the patient promptly recovered consciousness.

• Journal of Chest Surgery
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• v.24 no.5
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• pp.445-450
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• 1991

Forty eight patients diagnosed as atrial septal defect, had been operated from April 1986 to December 1990 at the Department of Thoracic and Cardiovascular Surgery, Inha University Hospital, were analysed retrospectively. Of the 48 patients, 12 patients, were male and 36 patients were female, Their ranged from 8 months to 51 years old, and the mean was 18.0 years old. The proceeding two symptoms were exertional dyspnea and frequent upper respiratory infection. But 10 patients [20.8%] were asymptomatic. Electrocardiographic findings were regular sinus rhythm in 100.0%, RVH in 29.2%, incomplete RBBB in 27.1%, and first degree AV block in 2.1%. Hemodynamic studies were performed in 38 of 48 patients. Significant pulmonary hypertension[over 50mmHg in systolic pulmonary arterial pressure], which is the most serious risk factor, was developed in 4 patients[8.3%]. There was statistical significance between size of defect[cm2/BSA-M2] and systolic pulmonary arterial pressure[sPAP] retrospectively[p=0.036]. We could not find the correlationship between age and Qs % size. Anatomically, secundum type constituted 97.9%, in which 43 patients were PFO type[91.6%] and 3 patients were IVC type[6.3%]. 38 of 48 ASD patients were repaired with patch closure[72.9%] and remains were repaired with direct closure[27.1%]. The operative result was excellent except two cases of transient postoperative arrhythmia. There was no operative mortality.

• Current Photovoltaic Research
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• v.5 no.2
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• pp.59-62
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• 2017

Surface texturing is affected the uniformity and size of pyramid with saw mark defect density. To analysis the influence of the saw mark defect density, we textured various si wafer. When the texturing process proceeds without the saw mark removal, silicon wafer of low-saw mark defect density showed small pyramid size of $3.5{\mu}m$ with the lowest average value of the reflectance of 10.6%. When texturing carried out after removal of the saw mark using the TMAH solution, we obtained a reflectance of about 11% and the large pyramid size of $5{\mu}m$. As a result, saw mark wafers showed a better pyramid structure than saw mark-free wafer. This result showed that saw mark can take place more smooth etching by the KOH solution and saw mark-free wafer is determined to be a factor that have a higher reflectance and a large pyramid.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1380-1383
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• 2007

The secondary electron emission coefficient (${\gamma}$) of the cathode is an important factor for improving the discharge characteristics of AC-PDP, because of its close relationship to discharge voltage. In this experiment, we have investigated the electronic structure of the energy band in the MgO layer responsible for the high ${\gamma}$. We used three kinds of MgO pellet that have another component, and each MgO layers have been deposited by electron beam evaporation method. The work-functions of MgO layer have been investigated from their ion-induced secondary electron emission coefficient (${\gamma}$), respectively, using various ions with different ionization energies in a ${\gamma}-FIB$ (Focused Ion Beam) system. We have compared work-function with ${\gamma}-FIB$ system current signal for measurement defect energy level in MgO layer. MgO-A in the three types has lowest work-function value (4.12eV) and there are two defect energy levels.

• Korean Journal of Crystallography
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• v.14 no.2
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• pp.84-92
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• 2003

The fast pulling is easy to modify the distribution of grown-in defects toward fine size, which can be readily removed by additional treatment. In this experiment, The fast pulled crystals with high pulling late over 1.0 mm/min were grown and their grown-in defect distributions were investigated. In our recent developments in the growth of Cz-Si, it could be found that the cooling rate in a specific temperature range and the uniformity of temperature gradient at solid/liquid interface are more important for the formation of grown-in defect than the pulling rate itself. We analyzed these cooling rates and temperature gradients for the various fast pulled crystals and compared them to the observed formation behavior of the grown-in defects. The effective factor (Ω) for the void defect formation was introduced and it could explain the radial distribution of void defects in the fast-pulled crystals effectively.