• Journal of the Korea Institute of Building Construction
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• v.8 no.2
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• pp.81-87
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• 2008

High-rise building is taking a place as one of building types from apartment housings to commercial buildings. With taking in account of stability and durability, strength of used materials is increasing gradually in these high-rise buildings. According to this, frequency in use of SD500 re-bar is increasing gradually in high-rise buildings. However the study of SD500 re-bar is insufficient because SD500 re-bar started to be used for domestic buildings lately. Specially because there is no guide or study to refer to, people get into difficulties when to decide the method of re-bar connection in construction using SD500 re-bar. Accordingly in this study, it suggests the method of estimating the economical efficiency on SD500 re-bar connection, and conducts benefit/ cost analysis on lapped splice and coupler splice by applying AHP theory, and then presents its result. After to analyze re-bar diameter of D25, 29, and 32, finally we attained the result that the coupler splice is advantageous in all parts of benefit/ cost more than the lapped splice.

• Korean Journal of Soil Science and Fertilizer
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• v.28 no.2
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• pp.165-175
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• 1995

To determine the effect of soil moisture stress on growth of barley and grain quality, a pot experiment was carried out for two barley varieties(Olbori and Chogangbori) by using large plastic pot(52cm in diameter and 55cm in depth) filled with sandy loam soil under rain-controlled open green house. By means of measuring soil water potential with micro tensiometer and gypsum block installed at 10cm in soil depth, soil moisture was controlled by sub-irrigation at several irigation points such as -0.05bar, -0.2bar, -0.5bar, -1.0bar, -5.0bar and -10.0bar in soil water potential. The lower soil water potential was controlled, the shorter length of stem and internode became, and the more narrow stem diameter was. Leaf area was significantly decreased when soil water potential was controlled lower than -0.5bar, although chlorophyll content of flag and first leaves was not changed so much. Weight of grain and ear was significantly decreased when soil water potential was lower than -5.0bar and the highest grain yield was obtaind in a plot where soil water potential was controlled at -0.2bar. However, the most efficient water use of Olbori and Chogangbori was obtained at -0.5bar and -1.0bar in water potentials, respectively. Crude protain content, maximum viscosity, consistency and ${\beta}$-glucan content of barley flour increased as soil water potential significantly decreased, especially below -5.0bar, but gelatination temperature decreased as soil water potential decreased.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.5
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• pp.109-115
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• 2016

A demand of high bearing capacity of piles to resist heavy static loads has been increased. For this reason, the utilization of large diameter PHC piles including a range from 700 mm to 1,200 mm have been increased and applied to the construction sites in Korea recently. In this study, in order to increase the flexural strength capacity of the PHC pile, the large diameter composite PHC pile reinforced by in-filled concrete and reinforcement was developed and manufactured. All the specimens were tested under four-point bending setup and displacement control. From the strain behavior of transverse bar, it was found that the presence of transverse bar was effective against crack propagation and controlling crack width as well as prevented the web shear cracks. The flexural strength and mid-span deflection of LICPT specimens were increased by a maximum of 1.08 times and 1.19 times compared to the LICP specimens. This results indicated that the installed transverse bar is in an advantageous ductility performance of the PHC piles. A conventional layered sectional analysis for the pile specimens was performed to investigate the flexural strength according to the each used material. The calculated bending moment of conventional PHC pile and composite PHC pile, which was determined by P-M interaction curve, showed a safety factor 1.13 and 1.16 compared to the test results.

• Journal of the Korean Society of Safety
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• v.21 no.1 s.73
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• pp.92-95
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• 2006

This study is to find out how column with hole is behaved, compared to the normal one without hole. There might be existing buildings to make holes in the reinforced concrete column. Columns are made with commercially used compressive strength $240kg/cm^{2}$, air amount 5.0%, using re-bar of diameter D13 and D10 having yielding stress $4,000kg/cm^{2}$. The specimen were cured with temperature of $21{\pm}3^{\circ}C$. All specimens of five variables and all holes are geometrically considered and configurated. D3, D5 mean diameter 3cm and 5cm respectively. H1, H2 are the number of holes. Compressive pressure was forced in accordance with KS, following $0.6{\pm}0.4N/mm^{2}$ speed. Main re-bar's were strained with almost same shape through all the specimens. Hole diameter 5cm-having specimen showed cracking around hole. strains of back and front gauges of the specimen were showed similarly. Specimen having two holes in left and right from longitudinally axis resisted 7% less than the one having hole centrically from longitudinal axis. One hole having specimen with diameter 5cm resisted only 3% less than in case of 3cm diameter hole. Hole having in left and right from longitudinal axis will be less resistant than the case longitudinally arranged. Diameter 3cm hole showed less 10% capacity than normal one without hole. Capacity loss difference between diameter 3cm and 5cm showed almost none in case that they are arranged longitudinally.

• Journal of the Korean Society of Hazard Mitigation
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• v.7 no.4
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• pp.13-18
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• 2007

The research was performed to review the design factors which affect the durability of structures. For the study, domestic and foreign literature review were performed on various design criteria. Based on Korean standard specifications, the results showed that the durability of structure as the diameter of reinforcing steel bar becomes smaller and the distance between reinforcing bar is closer than the normal gap. The results were also presented that the minimum required bar cover is 6.6cm to obtain the durability index value. In addition, the maximum limited bar cover was 12cm considering the durability index and the change of increasing value of durability index. In case that there is no specified regulation for the bar cover thickness change, the durability life by neutralization is proportional to the thickness of bar cover.

• Journal of Gastric Cancer
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• v.2 no.1
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• pp.29-32
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• 2002

A gastroduodenostomy is the most physiological reconstruction after a distal gastrectomy. However, a gastroduodenostomy with either sutures or staples has many complications. These include bleeding, leakage and stenosis. A sutureless gastroduodenostomy with a biofragmentable anastomosis ring (BAR) in was used adenocarcinoma patients to prevent these complications from 1999. A BAR is composed of polyglycolic acid and Barium sulfate to allow for X-ray visualization. Hardy in first introduced the BAR in 1985. Since then, it has been used in an anastomosis of the colon or small bowel surgery but its use in a gastroduodenostomy is the first trial in the world. A 70 year male patient, old who received a subtotal gastrectomy (Billroth I), underwent a A sutureless gastroduodenostomy with a BAR. The gastroduodenostomy with the BAR was watertight and maintained the initial burst strength in the gastrografin X-ray study performed at the postoperative 1 week. The BAR began to fragment 3 weeks after the operation and disappeared from the digestive tract completely. The diameter of the anastomosis site was sufficient for passed foods. No other secondary changes from remained foreign bodies were found in the endoscopic examination. In a second operation to treat a primary hepatoma, there was no adhesive changes around the gastroduodenostomy site. In conclusion, a sutureless gastroduodenostomy with BAR is a safe, easy and efficient reconstructive method after a distal gastrectomy.

• Journal of the Korea Concrete Institute
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• v.29 no.2
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• pp.201-208
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• 2017

In exterior beam-column joints, hooked bars are used for anchorage, but usage of high-strength and large-diameter bars increases, headed bar is preferred for solving steel congestion and difficulty in construction. To investigate the structural performance of headed bars, Six exterior beam-column joints were tested under cyclic loading. Tests parameter were the anchorage methods and concrete strength. The test results indicate that behavior of headed bar specimens shows similar performance with hooked bar specimens. All specimens failed by flexural failure of the beam. Headed bar specimens shows better performance in anchorage and joint shear. All specimens were satisfied the criteria of ACI374.1-05. Test results indicate that use of headed bar in exterior beam column joint is available.

• Journal of the Korean Society for Nondestructive Testing
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• v.20 no.4
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• pp.305-313
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• 2000

To determine detection capabilities of locating steel bars and delamination inside concrete, commercially available nondestructive testing (NDT) equipments have been tested. The equipments include two radar systems and two electromagnetic method systems. The inclusions are a 19 mm diameter steel bar and 50 mm thick delamination embedded at different cover depths from the surface of concrete specimens. For the steel bar, attempts were made to determine the size of the bars by changing the diameter of the bars. A sample result of measuring horizontal spacing between doubly reinforced bars is presented in this paper. Experimental results on various measurement cases are discussed. Application of numerical modeling technique for the simulation of radar measurements and improved output display of radar measurements are also presented.

• Communications of the Korean Mathematical Society
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• v.32 no.1
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• pp.7-17
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• 2017

Let R be a commutative ring with zero-divisors Z(R). The extended zero-divisor graph of R, denoted by $\bar{\Gamma}(R)$, is the (simple) graph with vertices $Z(R)^*=Z(R){\backslash}\{0\}$, the set of nonzero zero-divisors of R, where two distinct nonzero zero-divisors x and y are adjacent whenever there exist two non-negative integers n and m such that $x^ny^m=0$ with $x^n{\neq}0$ and $y^m{\neq}0$. In this paper, we consider the extended zero-divisor graphs of idealizations $R{\ltimes}M$ (where M is an R-module). At first, we distinguish when $\bar{\Gamma}(R{\ltimes}M)$ and the classical zero-divisor graph ${\Gamma}(R{\ltimes}M)$ coincide. Various examples in this context are given. Among other things, the diameter and the girth of $\bar{\Gamma}(R{\ltimes}M)$ are also studied.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.1
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• pp.163-171
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• 2000

The aim this study is to provide fundamental informations for the development of magneticfluid damper. To achieve the aim. the damping effect of magneticfluid is investigated by experiments that the diameter of inner circular bar and the input amplitude vary in the magnetic field generated by the permanent magnet and the electromagnet. From the study, the following conclusive remarks can be made. As the diameter of inner circular bar and the input amplitude increase. the damping effect is improved. And we can know that as the contact area between inner circular bar and magneticfluid increases, damping ratio is improved. Also we consider the cases that there is magnetism generated by electromagnet and DC voltage is supplied to electromagnet from 10V to 50V by 10V. In these cases, the amplitude ratio decreases sharply from 1.8 1.0 And for these cases, the damping ratio is .745.