• Journal of the Korea Concrete Institute
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• v.24 no.3
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• pp.275-283
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• 2012

Steel Plate for Rebar Connection was recently developed to splice rebars in delayed slab-wall joints in high-rise building, slurry wall-slab joints, temporary openings, etc. It consists of several couplers and a thin steel plate with shear key. Cyclic loading tests on slab-wall joints were conducted to verify structural behavior of the joints having Steel Plate for Rebar Connection. For comparison, joints with Rebend Connection and without splices were also tested. The joints with Steel Plate for Rebar Connection showed typical flexural behavior in the sequence of tension re-bar yielding, sufficient flexural deformation, crushing of compression concrete, and compression rebar buckling. However, the joints with Rebend Connection had more bond cracks in slabs faces and spalling in side cover-concrete, even though elastic behavior of the joints was similar to that of the joints with Steel Plate for Re-bar Connection. Consequently, the joints with Rebend Connection had less strengths and deformation capacities than the joints with Steel Plate for Re-bar Connection. In addition, stiffness of the joints with Rebend Connection degraded more rapidly than the other joints as cyclic loads were applied. This may be caused by low elastic modulus of re-straightened rebars and restraightening of kinked bar. For two types of diameters (13mm and 16mm) and two types of grades (SD300 and SD400) of rebars, the joints with Steel Plate for Rebar Connection had higher strength than nominal strength calculated from actual material properties. On the contrary, strengths of the joints with Rebend Connection decreased as bar diameter increased and as grade becames higher. Therefore, Rebend Connection should be used with caution in design and construction.

• The Journal of Korean Academy of Prosthodontics
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• v.61 no.3
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• pp.179-188
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• 2023

Purpose. The purpose of this study was to evaluate the effect of surface treatments on the shear bond strength of two types of zirconia (3-TZP and 5Y-PSZ) with resin cement. Materials and methods. Two different types of zirconia specimens with a fully sintered size of 14.0×14.0×2.0 mm³ were prepared, polished with 400, 600, and 800 grit silicon carbide paper, and buried in epoxy resin. They were classified into four groups each control, sandblasting, primer, and sandblasting & primer. Cylindrical resin adhered to the surface-treated zirconia with resin cement. It was stored in distilled water (37℃) for 24 hours, and a shear bond strength test was performed. The normality of the experimental group was confirmed with the Kolmogorov-Smirnov & Shapiro-Wilk test. The interaction and statistical difference were analyzed using a two-way ANOVA. A post-hoc analysis was performed using Dunnett T3. Results. As a result of two-way ANOVA, there was no significant difference in shear bonding strength between zirconia types (P > .05), but there was a significant correlation in the sandblasting, primer, and alumina sandblasting & primer group (P < .05). Dunnett T3 post-test showed that, regardless of the type of zirconia, shear bonding strength was sandblasting & primer > Primer > sandblasting > control group (P < .05). Conclusion. There was no difference in shear bond strength between the types of zirconia. The highest shear bond strength was shown when the mechanical and chemical treatments of the zirconia surface was performed simultaneously.

• Journal of Life Science
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• v.20 no.4
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• pp.614-617
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• 2010

We sequenced a 522 bp fragment including the $tRNA^{Thr}$, $tRNA^{Pro}$ gene and the first half of the control region from 29 wild and cultured olive flounder specimens from Korea. Out of 522 nucleotide sites, 49 (9.4%) were variable, 23 haplotypes being found. Most haplotypes are unique in the wild population and only four were shared by cultured specimins. The nucleotide diversity and differences between wild and cultured populations were $0.025{\pm}0.013$ and $0.015{\pm}0.008$, and $12.94{\pm}6.00$ and $7.83{\pm}3.75$, respectively. Haplotype diversity was $0.98{\pm}0.02$ and $0.49{\pm}0.09$ in the wild and cultured populations, respectively. These results show that marked reductions of genetic variability in the hatchery strains were observed in the number of mitochondrial DNA haplotypes and haplotype diversity when compared to the wild populations. Furthermore, we detected significant population differentiation between both populations. The mtDNA sequencing technique used to evaluate the genetic variability of hatchery strains compared to that of the wild population is potential for genetic monitoring of olive flounder hatchery stocks.

• KOMUNHWA
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• no.65
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• pp.81-106
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• 2005

This study researches the publishing circumstances and the woodblocks used in the local government office at Jeollado in Joseon dynasty. Wanyung woodblocks indicate the printing blocks which were used in Jeolla local office. Known so far, there were 11 so

• Korean Journal of Head & Neck Oncology
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• v.11 no.1
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• pp.41-46
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• 1995

The pectoralis major myocutaneous flap represents a major contribution to head and neck cancer reconstruction. Its advantages are improved viability, one-stage reconstruction, and carotid protection. The oropharyngeal defect especially tonsillar area reveals valley shaped one with loss of a wide mucosal area. Using pectoralis major myocutaneous flap to this defect is sometimes difficult due to its natural figure of bulkiness. This article reviews our experience with patients undergoing 14 pectoralis major myocutaneous flap in carcinoma of the tonsillar area. Complications and their incidences were I total loss, 3 marginal loss, 2 minor seperation of suture, I wound infection and 2 hematoma. Most of the complications did not require a second procedure for reconstruction. Bulkiness of the flap and gravity force to the upper suture line were thought to be causes of the complications. Modification of the flap design with bilobular figure was useful to reduce its bulkiness at the folding area. More stable suture around hard palate was needed to overcome seperation of the suture.

• Communications of Mathematical Education
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• v.31 no.3
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• pp.241-255
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• 2017

The 4th industrial revolution is coming. In order to prepare for the new learning environment with it, we may need digital mathematics textbooks that fully utilize all possible technologies. So various attempts have been made in elementary and middle school mathematics education. However, despite the importance of higher mathematics, we haven't seen a best possible math digital textbooks yet in Korea. In this paper, we introduce our new model of interactive math digital textbook about Linear Algebra/ Calculus/ Differential Equations/ Statistics/ Engineering Math. Especially, this manuscript focuses on our experience of using digital contents and interactive labs for developing a new model for linear algebra digital textbook. We introduce our works on linear algebra digital textbooks which include pdf e-book, web contents, video clips of lectures, interactive lab. Using this linear algebra digital textbook, students can freely use any mobile devices to access diverse learning materials, lessons, and hands-on exercises without any limitations. Also, times saved in the computation, coding, and typing process can be used to have more discussions for deeper understanding of mathematical concepts. This type of linear algebra digital textbook, which contains all interactive free cyber-lab with codes and all lectures for each sections, can be considered as a new model for the next generation of math digital textbook.

• Journal of Food Hygiene and Safety
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• v.35 no.3
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• pp.234-242
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• 2020

In this study, we monitored the raw materials in home-meal replacement (HMR) products, which have shown more than 63% growth in market size for two years. A total of 89 HMR products were purchased and the DNA barcodes of 112 raw materials in the product samples were analyzed. In order to identify the raw material species, a primer set specific for the 16S ribosomal RNA region of each raw material species was amplified. The amplicon was purified and sequenced, and then used to perform a BLAST search provided by the National Institutes of Health (NIH). The species of the raw material was determined by comparing the nucleotide sequences of the species registered in GenBank with identity and match score. Twenty-four species and three genera were identified from 112 raw materials. Three genera were identified at the genus level because a large number of species belonging to the same genus exist within 98% of the identity criteria. The results of the determination were compared with the available raw materials suggested in the Korea Food Code to determine the Korean name and availability of the foods. Six non-listed species were determined to be edible according to information provided by influential domestic and foreign organizations.

• The Korean Journal of Pesticide Science
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• v.14 no.4
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• pp.347-360
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• 2010

In order to develop the multi-residue purification method for 180 pesticides commonly used in Korea, many analytical methods on individual and multi- pesticide residues in the agricultural commodities and food product were examined. Through the modification of adsorption chromatographic methods used in Europe, the United States and Korea, the Florisil and silica-gel chromatographic systems were developed. Through these purification systems, elution profiles for all pesticides were examined. As the results, 145 pesticides were recovered in the range of 70-120% in Florisil clean-up system. The distribution of pesticides in the elution profile was 12 pesticides in the first fraction, 76 pesticides in the second fraction, 81 pesticides in the third fraction, 60 pesticides in the fourth fraction and 30 pesticides in the last fraction. And, in silica-gel system, 137 pesticides were recovered in the range of 70~120%. The distribution of pesticides in the elution profile was 22 pesticides in the first fraction, 59 pesticides in the second fraction, 102 pesticides in the third fraction, 46 pesticides in the fourth fraction and 8 pesticides in the last fraction.

• Journal of the Korea Organic Resources Recycling Association
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• v.9 no.4
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• pp.71-80
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• 2001

In order to evaluate the effectiveness of the organic and natural farming techniques, the actual conditions of the techniques were surveyed and some crops were cultivated in situ. The contents of available $P_2O_5$, exchangeable $Ca^{2+}$ and organic matter of the organic and natural farming soil as well as soil pH were higher than those of the non-organic and non-natural farming soil, and especially the content of organic matter amounting 54.0 g/kg was dominant. Income of the farmers cultivating the different crops with the organic and natural farming was high in order of red pepper in vinyl house > cucumber in vinyl house > fruit(pear) > lettuce in vinyl house > rice. The agricultural materials used in organic and natural farming were ranged from 22 to 25 kinds, representing low pH amounted from 2.9 to 4.5 and low contents of fertilizer ingredients. The expense for purchasing the materials was from three to five times higher than that of soil testing plot. The yields of test crops in the organic and natural farming plots were lower than those of soil testing plot, and the efficiencies of the disease and pest control by the application of the substitutes for pesticide were lower than those by pesticides.

• Asian Journal of Turfgrass Science
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• v.25 no.1
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• pp.43-47
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• 2011

Creeping bentgrass (Agrosis stolonifera L.) is regarded to be the most widely used cool-season turf grass species grown on golf greens and fairways in temperate climates of North America. Creeping bentgrass is highly susceptible to the fungal disease 'dollar spot' caused by Sclerotinia homoeocarpa. Dollar spot is a foliar disease favored by conditions of high humidity, warm days, and cool nights. Studies using Aliette Signature (Fosetyl Aluminum formulated with a green pigment) mixed with another broad-spectrum fungicide do not always provide additional visual quality benefits compared to the fungicide alone. The exact mechanism for improved summer visual quality, when it occurs, is not known. Fertility management and environment likely contribute. The object of this study is to evaluate fungicide strategies for control of dollar spot and effect on visual quality during summer and on an L-93/G-2 creeping bentgrass green. Nine fungicide combinations were used for this study. Disease control and visual quality by fungicides was evaluated on an established G-2/L-93 creeping bentgrass green at 3-hole Sunshine Golf Course in Lemont, IL. All fungicide combination showed excellent dollar spot suppression except Fore throughout the study. Visual quality of greens by addition of Aliette Signature is enhanced when bentgrass growth is compromised and slow. Dollar spot levels in Fore plots increased to 30% on 14 August, and was no different than untreated plots. Unacceptable quality by Fore was due to lack of dollar spot control.