• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.402.1-402.1
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• 2014

Photonic force microscopy (PFM) is an optical tweezers-based scanning probe microscopy, which measures the forces in the range of fN to pN. The low stiffness leads proper to measure single molecular interaction. We introduce a novel photonic force microscopy to stably map various chemical properties as well as topographic information, utilizing weak molecular bond between probe and object's surface. First, we installed stable optical tweezers instrument, where an IR laser with 1064 nm wavelength was used as trapping source to reduce damage to biological sample. To manipulate trapped material, electric driven two-axis mirrors were used for x, y directional probe scanning and a piezo stage for z directional probe scanning. For resolution test, probe scans with vertical direction repeatedly at the same lateral position, where the vertical resolution is ~25 nm. To obtain the topography of surface which is etched glass, trapped bead scans 3-dimensionally and measures the contact position in each cycle. To acquire the chemical mapping, we design the DNA oligonucleotide pairs combining as a zipping structure, where one is attached at the surface of bead and other is arranged on surface. We measured the rupture force of molecular bonding to investigate chemical properties on the surface with various loading rate. We expect this system can realize a high-resolution multi-functional imaging technique able to acquire topographic map of objects and to distinguish difference of chemical properties between these objects simultaneously.

• Journal of the Korean Professional Engineers Association
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• v.14 no.3
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• pp.9-21
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• 1981

The rationalization for Tunnel Drifting is based on the high productivity which is achievable due to Continuous work with a Jumbo Drill, resulting in a much higher efficiency them the Conventional method of blasting, mucking and supporting services. Large projects of over 4,000m Tunnel Drifting are condidated to justify the use of a Jumbo Drill with a combination of superior explosives, machinery and techniques. During a Tunnel Drifting test, Gulita, Nabit and slurry made by Nitro Nobel were employed with following results. 1, Conditions: a. Granite Rock with Two free face b. Burden (W), 2m c. Diameter of hole, 42mm d. Depth of hole 3.5m e. Hole pitch 0.6m f. Charged Explosive per hole Gelatin Dynamite 4 pieces (112.5${\times}$4ea)+Guuita 5 pieces(110g${\times}$5ea) g. Simal-taneous Detonation h. After the blasting resultant rock size was Less 40% of the 0.3m Lumps. 2. Calculation results W=q/Wn=100cm‥‥‥Burden in simultaneous blasting 0.865kg(7.7ea)/hole ‥‥‥Amount of charge but hole pitch is 1.5W-2W The estimated cost of using a Jumbo Drill for the Construction of a 3,000,000 bbL sub-surface oil storage would be as follows: This calculation is based on the Jumbo Drill advancing 3.6m per blasting cycle. Unit cost/bbL Excavation $3.13 The attached sheet shows ideal Drilling pattern with Burn Cut & Smooth blasting method. In conclusion, it is my opinion that this method will assure safety and save cost and improve our technical know-how.

• Journal of Korean Society of Forest Science
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• v.96 no.1
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• pp.40-47
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• 2007

The objectives of this study were to derive site index and stem volume prediction equation based on stem analysis data for Larix leptolepis in Jinan region. The function for site index was developed by algebraic difference equation method. Polymorphic site index family curves with base age of 40 were presented based on the Schumacher height equation. The best stem volume prediction equation was suggested as $V=0.00260+0.00000399D^2H$. The simultaneous F-test using this equation showed that the estimated tree stem volumes were not significantly different (${\alpha}=0.05$ level) from the observed stem volumes for model evaluation. Therefore, site index and volume prediction equations prepared in this study could provide an indication of site quality and basic information for making of yield table, and could be used for rational forest management of Larix leptolepis stands grown in Jinan region.

• Journal of Periodontal and Implant Science
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• v.38 no.sup2
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• pp.309-316
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• 2008

Purpose: The aim of this study was to determine the survival rates of implants placed in grafted maxillary sinuses and compare the results obtained with graft materials, implant surfaces and timing of implant placement. Materials and Methods: Between January 1996 and December 2005, 391 implants were placed in 161 patients who underwent sinus grafting treatment simultaneously or separately at Ewha Womans University Hospital. According to inclusion criteria, 272 implants were placed in 102 patients with 112 sinus grafts (30 females, 72 males), aged 26 to 88 years (mean age $49.0{\pm}9.7$). The follow-up period ranged from 12 to 134 months (mean F/U $47{\pm}32$). Survival rates were evaluated according to graft material, implant surface and timing of implant placement. The Kaplan-Meier procedure and the log rank (Mantel-Cox) test were used to estimate survival rates and test for equality of survival rates between different groups of patients. Results: Ten-year cumulative survival rate for implants placed in the grafted sinuses was 90.1%. The survival rates for autogenous bone, combination and bone substitutes were 94.6%, 85.9% and 100%, respectively (p > 0.05). According to implant surface, survival rates were 84.8% in machined group and 97.5% in rough group (p < 0.05). The survival rates were 92.9% in delayed group and 86.0% in simultaneous group (p > 0.05). Conclusion: Ten-year cumulative survival rate for implants placed in the grafted sinuses was 90.1%. Rough-surfaced implants have a higher survival rate than machined-surfaced implants when placed in grafted sinuses (p < 0.05).

• Journal of Korean Critical Care Nursing
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• v.16 no.3
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• pp.62-72
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• 2023

Purpose : This study aims to assess the extent of work value, psychological ownership, the nursing work environment, and retention intention, examine the correlation between these variables, and identify the factors that influence retention intention. The goal is to provide foundational data to enhance retention intention. Method : The study involved 159 nurses employed at a tertiary general hospital and a general hospital. Data were gathered through structured questionnaires and analyzed using an independent t-test, one-way ANOVA, Scheffé test, Pearson correlation coefficient, and multiple regression analysis with a simultaneous stepwise method, all conducted using the SPSS 26.0 software. Results : The intention to remain in the profession was found to have a positive correlation with work value (r = .45, p < .001), psychological ownership (r = .37, p < .001), and the nursing work environment (r = .27, p = .001). Significant factors influencing the intention to stay included total clinical career (𝛽 = .17, p = .016), work value (𝛽 = .38, p < .001), and psychological ownership (𝛽 = .19, p = .020). These variables accounted for 24.1% of the variance in the intention to remain in the profession (F = 17.71, p < .001). Conclusion: To enhance the intention of hospital staff to remain in their positions, it is crucial to identify and bolster positive psychological competencies, such as a sense of work value and psychological ownership.

• Journal of the Korea Institute of Building Construction
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• v.23 no.2
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• pp.153-164
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• 2023

The objective of this study is to examine the removal rate of air pollutants, specifically sulfur oxides (SO_x) and nitrogen oxides(NO_x), using concrete permeable blocks containing zeolite beads coated with materials capable of eliminating these pollutants. Titanium dioxide(TiO₂) powder and coconut shell powder were utilized for the removal of SO_x and NO_x and were applied as coatings on the zeolite beads. Concrete permeable block specimens embedded with the coated zeolite beads were produced using an actual factory production line. Test results demonstrated that the concrete permeable block containing zeolite beads coated with coconut shell powder in the surface layer achieved SO_x and NO_x removal rates of 12.5% and 99%, respectively, exhibiting superior performance compared to other blocks. Additionally, the flexural strength and slip resistance were 5.3MPa and 65BPN or higher, respectively, satisfying the requirements specified in KS F 4419 and KS F 4561. Conversely, the permeability coefficient exhibited low permeability, with grades 2 and 3 before and after contaminant pollution, according to the standard for 'design, construction, and maintenance of pavement using permeable block'. In conclusion, incorporating zeolite beads coated with coconut shell powder in the surface layer enables simultaneous removal of SO_x and NO_x, irrespective of ultraviolet rays, while maintaining adequate flexural strength and slip resistance. However, the permeability is significantly reduced, necessitating further improvements.

• Geophysics and Geophysical Exploration
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• v.10 no.3
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• pp.191-202
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• 2007

To identify the detailed attenuation structure in the southern Korean Peninsula, a numerical test was conducted for the Q tomography inversion to be applied to the accumulated dataset until 2005. In particular, the stochastic pointsource ground-motion model (STGM model; Boore, 2003) was adopted for the 2D Q tomography inversion for direct application to simulating the strong ground-motion. Simultaneous inversion of the STGM model parameters with a regional single Q model was performed to evaluate the source and site effects which were necessary to generate an artificial dataset for the numerical test. The artificial dataset consists of simulated Fourier spectra that resemble the real data in the magnitude-distance-frequency-error distribution except replacement of the regional single Q model with a checkerboard type of high and low values of laterally varying Q models. The total number of Q blocks used for the checkerboard test was 75 (grid size of $35{\times}44km^2$ for Q blocks); Q functional form of $Q_0f^{\eta}$ ($Q_0$=100 or 500, 0.0 < ${\eta}$ < 1.0) was assigned to each Q block for the checkerboard test. The checkerboard test has been implemented in three steps. At the first step, the initial values of Q-values for 75 blocks were estimated. At the second step, the site amplification function was estimated by using the initial guess of A(f) which is the mean site amplification functions (Yun and Suh, 2007) for the site class. The last step is to invert the tomographic Q-values of 75 blocks based on the results of the first and second steps. As a result of the checkerboard test, it was demonstrated that Q-values could be robustly estimated by using the 2D Q tomography inversion method even in the presence of perturbed source and site effects from the true input model.

• Journal of Animal Science and Technology
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• v.44 no.4
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• pp.377-382
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• 2002

This study was carried out for the simultaneous genetic evaluation of swine breeds from the seedstock farms in Korea. The performance tested production records of 96,842 heads and the litter records of 90,396 litters from 1995 to 2001 were analyzed to estimate the breeding values and the breed effects of days to 90kg, daily gain, back fat thickness, loin muscle area, lean meat percent, total litter size and number born alive from Landrace, Yorkshire and Duroc. Estimated breed effects of traits had shown the characteristics of the breeds. Landrace was superior in back fat thickness and lean meat percent to other breeds. Yorkshire had shown good performance in lean meat percent, loin muscle area, total litter size and number born alive. Duroc was superior to the other breeds in days to 90kg and daily gain. Conclusively, the multi-breed genetic evaluation would result in higher connectedness and provide convenience for the routine genetic evaluation process of swine performance and reproduction test.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.43 no.1
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• pp.69-78
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• 2017

Hwangryunhaedoktang (HHT) has been traditionally used as a preventive and therapeutic medicine to treat enervation and diverse chronic diseases. This study was designed to compare the antioxidant, anti-wrinkle and whitening effects of HHT extract and its fermented extract by Leuconostoc mesenteroides (FHHT). FHHT was prepared by inoculation of L. mesenteroides after the extraction procedure with 70% ethanol. HHT and FHHT was investigated via high-performance liquid chromatography (HPLC). Simultaneous qualitative analysis of two bioacitive components, berberine and palmatine. was achieved by comparing their retention times ($t_R$) and UV spectra with those of the standard components. Cell viability test results indicated that both HHT and FHHT were non-toxic. In DPPH radical scavenging ability, $SC_{50}$ values of the FHHT was $68.85{\mu}g/mL$, which is more effective than HHT. Moreover, FHHT showed higher expression in production of procollagen type I than HHT. In nontoxic concentration range, FHHT showed strong melanin production inhibitory effect in ${\alpha}-melanocyte$ stimulating hormone (${\alpha}-MSH$)-stimulated B16F10 cell ($IC_{50}=9.82{\mu}g/mL$). These results suggested that fermented extracts of hwangryunhaedoktang had considerable potential as a cosmetics ingredient with an antioxidant and anti-wrinkle and whitening effects.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.43 no.3
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• pp.201-210
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• 2017

Scutellariae baicalensis (S. baicalensis) has been traditionally used for anti-inflammatory effect. This study was designed to compare the antioxidant and whitening effects of S. baicalensis extract and its fermented extract by Leuconostoc mesenteroides (L. mesenteroides). Fermented extract of S. baicalenins was prepared by inoculation of L. mesenteroides after the extraction procedure with 70% ethanol. S. baicalensis extract and its fermented extract was investigated via high-performance liquid chromatography (HPLC). Simultaneous qualitative analysis of two bioactive components; baicalin and baicalein was achieved by comparing their retention times ($t_R$) and UV spectra with those of the standard components. Cell viability test results indicated that both S. baicalensis extract and its fermented extract were non-toxicity. In DPPH radical scavenging ability, $SC_{50}$ values of the fermented extract was $34.43{\mu}g/mL$ as a result of more effective than S. baicalensis extract. In nontoxic concentration rage, fermented extract of S. baicalensis showed strong melanin production inhibitory effect in ${\alpha}$-melanocyte stimulating hormone (MSH)-stimulated B16F10 cell ($IC_{50}=68.17{\mu}g/mL$). These results suggested that fermented extracts of S. baicalensis has considerable potential as a cosmetics ingredient with an antioxidant and anti-wrinkle and whitening effects.