• 대한기계학회논문집
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• 제14권2호
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• pp.349-357
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• 1990

Power transmission characteristics and speed ratio-torque load-axial force relationship for a metal V-belt CVT were investigated theoretically and experimentally. In the metal V-belt CVT drive, it was found that the power was transmitted by thrust force and that band tension should be greater than compression force between the metal blocks. The experimental results for the speed ratio-torque load-axial force relationship showed good agreement with those predicted using equations developed from theoretical considerations.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 가을 학술발표회 논문집
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• pp.442-445
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• 1997

With increasing use of high strength concrete tied columns in structural engineering, it becomes necessary to examine the applicability of related sections of current design codes. High strength concrete has an advantage of strength capacity and stiffness especially for column elements. This paper presents an experimental study of high strength concrete tied columns subjected to eccentric loading. The main variables included in this test were concrete compressive strength, steel amount, eccentricity, and slenderness ratio. The concrete compressive strength varied from 34.9Mpa(356kg/$\textrm{cm}^2$ ) to 93.2Mpa(951kg/$\textrm{cm}^2$ ) and the longitudinal steel ratios were between 1.1% and 5.5%. The eccentricity was selected for the different failure modes, i.e., compression control, balanced point, and tension control. The slenderness ratio varied from 19 to 61. The column specimens with same slenderness ratio but with different concrete compressive strength were constructed and tested. The purpose of this paper is to show failure modes of high strength reinforced concrete columns.

• 한국농공학회지
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• 제44권6호
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• pp.115-123
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• 2002

This study was performed to provide basic data for development and construction of reinforced soil wall that mixed with reinforcements such as calcium carbonate, monofilament fiber. In order to determine proper moisture content and mixing ratio by weight of reinforcement, Poisson's ratio and compressive strength tests for sandy soil had been conducted. Model tests for long-term behavior of reinforced soil wall were carried out to investigate the effect of reinforcement during loads and under static loads. The results of creep and model tests for sandy soil compared with clayey soil. Reinforced sandy soil mixed with calcium carbonate and cement showed brittle rupture by shear but that of mixed with monofilament fiber showed ductile rupture due to the tension force of fiber. It was shown that when age increased, creep strain of reinforced soil under sustained load approached constant values.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회 논문집(II)
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• pp.989-994
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• 2000

Nine tests to failure are performed on full-scale eight composite beams with unreinforced web opening having ribbed slabs with formed deck which are perpendicular to the steel section and one steel beam. The effects of slab width, reinforcing of stud, moving of rib, moment-shear ratio are studied. At the low M/V ratio, Vierendeel action around the high moment end of the opening is occurred and the large deflection across the opening and transverse cracking are occurred with increasing of applied load. As the M/V ratio increases, the relative deflection across the opening decreases. And at failure, full tensile strain are occurred at bottom T section of steel beam, and concrete crushes at the High Moment End of the opening. With narrow slabs, diagonal tension failure at the high moment end of the opening is occurred. And with wide slabs, rib punch-through failure is occurred near the high moment end of the opening. The implications for design are discussed.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(II)
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• pp.529-532
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• 2005

The effects of polymer-binder ratio and ceramic powder content on the drying shringage and strength of polymer-modified pastes using redispersible polymer powders and ceramic powder are examined. As a result, the drying shrinkage of the polymer-modified pastes using redispersible polymer powders tend to decrease with increasing polymer-binder ratio and ceramic powder content. Regardless of the type of polymer powder, the tensile strength and adhesion in tension of the polymer-modified pastes with ceramic powder tend to increase with increasing polymer-binder ratio and ceramic powder content.

• International Journal of Concrete Structures and Materials
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• 제11권1호
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• pp.1-16
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• 2017

The compression or tension-controlled failure mode of concrete beams prestressed with unbonded FRP tendons is governed by the relative amount of prestressing tendon to the balanced one. Explicit assessment to determine the balanced reinforcement ratio of a beam with unbonded tendons (${\rho}^U_{pfb}$) is difficult because it requires a priori knowledge of the deformed beam geometry in order to evaluate the unbonded tendon strain. In this study, a theoretical evaluation of ${\rho}^U_{pfb}$ is presented based on a concept of three equivalent rectangular curvature blocks for simply supported concrete beams internally prestressed with unbonded carbon-fiber-reinforced polymer (CFRP) tendons. The equivalent curvature blocks were iteratively refined to closely simulate beam rotations at the supports, mid-span beam deflection, and member-dependent strain of the unbonded tendon at the ultimate state. The model was verified by comparing its predictions with the test results. Parametric studies were performed to examine the effects of various parameters on ${\rho}^U_{pfb}$.

• 한국안전학회지
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• 제12권2호
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• pp.57-64
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• 1997

Fatigue crack propagation behaviors and life prediction for SUS 321 plate and its electron beam weld metal were investigated using compact tension specimens. The larger the stress ratio is, the faster the crack propagates, but the variation of crack propagation rate decreases. The effect of stress ratio is greater in the slow crack propagation area than in the faster one. The crack propagation rate of electron beam weld metal is faster than that of base metal because of hardening, weld defect and residual stress in welding area. The crack propagation rate of transverse weld metal has a lower than that of base metal due to the effect of residual stress, but in the time of passing through welding area, has a higher rate. The crack propagation rate using $\Delta$K$_{eff}$ can be well plotted regardless of stress ratio. The fatigue life prediction method of considering crack closure more exactly predicts fatigue life than conventional one. conventional one.e.

• 동의신경정신과학회지
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• 제26권4호
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• pp.383-406
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• 2015

Objectives: People with tension-type headache generally take pain relievers, but long term dependency causes problems as well as side effects. The present study aimed to provide clinical evidence of herbal medicine for tension-type headache by systematic review of randomized controlled trials on the effect of herbal medicine for tension-type headache. Methods: Randomized or quasi-randomized controlled trials that verified effects of herbal medicine intervention on patients with tension-type headache were included in the study. A literature search of English, Japanese, Chinese, Korean databases was performed. The selected literature were assessed by Jadad scale and Risk of Bias. Results: Herein, 40 reports were selected from a total of 157. Meta-analyses of 2 trials indicated that the effective rate was significantly higher in the herbal medicine treatment group, as compared to the placebo control (risk ratio: 1.49, 95% confidence interval (CI): 1.23 to 1.80, p<0.0001, I²=0%). Four trials that compared herbal medicine with routine care with routine care only group showed a significantly higher effective rate of benefits for herbal medicine with routine care, as compared to routine care only (RR: 1.57, 95% CI: 1.18 to 2.10, p=0.002, I²=0%). Conclusions: The effective rate was significantly higher than control and adverse events were less in the treatment group. Pattern analysis (辨證) indicated that the studies on wind-fire pattern (風火證) were highest. Yougeun-bang (柔筋方) in prescription and Paeoniae Radix Alba (白芍藥) in medicinal herbs were most used. This finding could be widely utilized in future clinical practice and form the basis for the development of clinical practice guidelines in advance.

• Earthquakes and Structures
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• 제12권1호
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• pp.23-34
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• 2017

Composite steel plate deep beam (CDB) is proposed as a lateral resisting member, which is constructed by steel plate and reinforced concrete (RC) panel, and it is connected with building frame through high-strength bolts. To investigate the seismic performance of the CDB, tests of two 1/3 scaled specimens with different length-to-height ratio were carried out under cyclic loads. The failure modes, load-carrying capacity, hysteretic behavior, ductility and energy dissipation were obtained and analyzed. In addition, the nonlinear finite element (FE) models of the specimens were established and verified by the test results. Besides, parametric analyses were performed to study the effect of length-to-height ratio, height-to-thickness ratio, material type and arrangement of RC panel. The experimental and numerical results showed that: the CDBs lost their load-carrying capacity because of the large out-of plane deformation and yield of the tension field formed on the steel plate. By increasing the length-to-height ratio of steel plate, the load-carrying capacity, elastic stiffness, ductility and energy dissipation capacity of the specimens were significantly enhanced. The ultimate loading capacity increased with increasing the length-to-height ratio of steel plate and yield strength of steel plate; and such capacity increased with decreasing of height-to-thickness ratio of steel plate and gap. Finally, a unified formula is proposed to calculate their ultimate loading capacity, and fitting formula on such indexes are provided for designation of the CDB.

• 한국의류학회지
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• 제20권6호
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• pp.1107-1115
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• 1996

An investigation made of the easing contraction ratio according to sewing condition (seam line; wp, wf, 45$^{\circ}$ bias, stitch density; 13 stitch/cm (0.8 mm), 9 stitch/cm (1.1 mm), 6.5 stitch/ cm (1.5 mm), 5 stitch/cm (2 mm), 4 stitch/cm (2.5 mm), thread; sp 60$^{\circ}$s/2, sp 60$^{\circ}$s/3, st 60$^{\circ}$s/3, st 50$^{\circ}$s/3)) by lockstitch industrial sewing machine with shirring foot. The correlations of the easing and sewing conditions were by SPSS PC), and visual test was done by enlarged photo. The results obstained were as follows:. 1. The easing contraction ratio is increased in proportion to the low of stitch density. 2. The easing contraction ratio of wp, 45$^{\circ}$ bias is correlated with stitch density, and that of wf be with stitch density, elongation & weight. 3. The easing contraction ratio of 13 stitch/cm (0.8 mm), 9 stitch/cm (1.1 mm), 6.5 stitch/ cm (1.5 mm), 5 stitch/cm (2.0 mm) is correlated with flexible rigidity, and that of 4 stitch/ cm (2.5 mm) be with flexible rigidity and crease-resistance. 4. As a results of SPSS PC+ statistics, the easing contraction ratio is statistically correlated to the seam line, stitch density, upper thread tension, and fabric characteristics. 5. As a results of visual test by the enlarged photo, the limit of stitch density for easing contraction was 5 stitch/cm (2.0 mm).