• Elastomers and Composites
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• 제20권1호
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• pp.25-39
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• 1985

Elastomer-filler interaction in terms of characterization of filler effects was studied using natural rubber(NR) loaded with kaolin fillers modified with sodium polyphosphate and poly(maleic anhydride), respectively. Kaolins modified with sodium polyphosphate or poly(maleic anhydride) show adhering characteristics by Kraus plot. Reinforcement activity according to Cunneen-Russell method is given by those fillers, in which sodium polyphosphate-treated kaolin presents more favorable results than that treated with poly(maleic anhydride) with respect to adhesion constant, reinforcement extent, elastic constant, and crosslink density. When applied to Blanchard's linkage reinforcement theory, NR vulcanizates loaded with kaolin modified with sodium polyphosphate meet the requirements for both approximate linkage reinforcement(${\psi}'$) of 1.02 to 4.94 and accurate linkage reinforcement($\psi$) of 1.00 to 1.18, representing the values of effective wetting($C_{\psi}$) for 0.001 to 0.029 and intrinsic linkage reinforcement(${\psi}_0$) for 1.015 to 1.124, respectively, whille negligible linkage reinforcement is shown by NR vulcanizates loaded with kaolin treated with poly(maleic anhydride). Dynamic storage modulus(G') given by surface modified kaolins presents more favorable crosslink density rates of $2.260{\times}10^{-5}\;mole/cm^3-min$. for sodium polyphosphate treated kaolin and $1.305{\times}10^{-5}\;mole/cm^3-min$. for poly(maleic anhydride) treated kaolin, respectively, compared to untreated kaolin showing the rate of $1.033{\times}10^{-5}\;mole/cm^3-min$.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 추계 학술발표회 제20권2호
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• pp.855-858
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• 2008

초고강도 콘크리트의 개발에 따라 철근 압축이음에 대한 연구 필요성이 높아지고 있다. 인장이음과 마찬가지로 압축이음에서도 이음길이와 콘크리트 강도가 가장 큰 영향인자가 되며, 다음으로 압축이음에 영향을 주는 요인으로는 횡방향 보강근과 철근 지름이다. 횡방향 보강근은 이음부에서 발생된 인장응력에 저항하며, 인장이음에서는 철근 순간격 또는 피복두께와 동일한 역할을 수행하는 것으로 평가된다. 휨부재의 인장측에 주로 적용되는 인장이음은 슬래브처럼 횡보강근이 없는 경우도 있다. 그러나 압축이음이 적용되는 부재는 높은 축력이 작용되는 수직부재로, 압축 주근의 좌굴방지, 코어 콘크리트의 구속, 그리고 전단강도의 발현을 위해 횡보강근이 배근된다. 이를 활용함으로써 보다 경제적인 설계가 가능해진다. 본 연구에서는 실제 구조물에서 필연적으로 발생되는 횡방향 보강근에 대한 압축이음의 거동과 강도 특성을 실험을 통해 규명하고자 한다.

• Structural Engineering and Mechanics
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• 제84권2호
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• pp.239-251
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• 2022

The use of lateral reinforcement in confined concrete columns can improve bearing capacity and deformability. The lateral responses of lateral reinforcement significantly influence the effective confining pressure on core concrete. However, lateral strain-axial strain model of concrete columns confined by lateral reinforcement has not received enough attention. In this paper, based on experimental results of 85 concrete columns confined by lateral reinforcement under axial compression, the effect of unconfined concrete compressive strength, volumetric ratio, lateral reinforcement yield strength, and confinement type on lateral strain-axial strain curves was investigated. Through parameter analysis, it indicated that with the same level of axial strain, the lateral strain slightly increased with the increase in the unconfined concrete compressive strength, but decreased with the increase in volumetric ratio significantly. The lateral reinforcement yield strength had slight influence on lateral strain-axial strain curves. At the same level of lateral strain, the axial strain of specimen with spiral was larger than that of specimen with stirrup. Furthermore, a lateral strain-axial strain model for concrete columns confined by lateral reinforcement under axial compression was proposed by introducing the effects of unconfined concrete compressive strength, volumetric ratio, confinement type and effective confining pressure, which showed good agreement with the experimental results.

• 대한간호학회지
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• 제17권3호
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• pp.177-183
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• 1987

This study investigated and evaluated a method effectively promote a communication function in families with a schizophrenic patient and the patients' interaction, by a family approach using reinforcement of functional communication between patients and their parents. The subjects of the study were patients receiving treatment in Won Gwang University Mental Hospital from July 1985 to July 1986, and their families. In the experimental group, a family approach using reinforcement of functional communication twice a week was taught. Each of the six sessions took sixty minutes, during which the interviews and questionaires were carried out. The total number of patients receiving treatment in the hospital at that time, 42, were divided by a systematic method into 20families in an experimental group and 22 in a control group. The results from testing the hypotheses established in this study, to analyse the effects of family approach through reinforcement of functional communication, are as follows; The results of the test of the first hypothesis are shown in Table 1. “patients and their parents in an experimental group receiving group training in reinforcement of functional communication will show a greater degree of interaction than those of the control group” was supported. Significant differences included Main Effects p＜.001, Interactions p＜.001 and Explained p＜.001 in the interactions of patients, and mothers. Scores were higher for the experimental group after the treatment as well as higher than the control group.

• 한국초전도ㆍ저온공학회논문지
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• 제3권1호
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• pp.6-10
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• 2001

Stress/stram dependencies of the critical current $I_c$ in AgMgNi sheathed multifilamentary Bi(2212) superconducting tapes were evaluated at 77K, 0T. The external reinforcement was accomplished by soldering Ag-Mg tapes to sin91e side or both sides of the sample. With the external reinforcement. the strength of tapes increased but $I_c$, decreased The $I_c$, degradation characteristic according to the external reinforcement was improved markedly in terms of the stress although it appeared less rectal.table on the basis of the strain. Effects of external reinforcement were discussed in a viewpoint of monitoring sensitivity of cracking in superconducting filaments by considering n-value representing the transport behavior of the current. It is closely associated with the location of them relative to the voltage-monitoring region in the tape.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 봄 학술발표회논문집(II)
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• pp.493-498
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• 1998

An experimental investigation was conducted to examine the behavior of high-strength concrete R/C columns subjected to moment, shear and axial load. The test parameters of specimens were the compressive strength of concrete(f'c=250, 516, 600kg/ ㎠), space of lateral reinforcement (20, 30, 37cm) and lateral reinforcement ratio(ρs=2.1, 3.15%). Test results indicated that compressive strength of concrete and lateral reinforcement can significantly affect and alter the behavior of column under inelastic cyclic loadings. Despite of the defaults of high-strength concrete, with increased amount of lateral reinforcement ratio to core concrete and added sub-lateral reinforcement, ductility and strength of RC columns used high-strength concrete can secured.

• Corrosion Science and Technology
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• 제11권5호
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• pp.157-164
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• 2012

In first experiment series, this paper is devoted for examining progress of reinforcement corrosion due to carbonation in concrete and to quantify uncarbonation depth to protect reinforcement from corroding. The tolerance of cover depth should be considered in order to prevent carbonation-induced corrosion. From the relationship between the weight loss of reinforcement and corrosion current density for a given time, therefore, the tolerance of cover depth to prevent carbonation-induced corrosion is computed. It is observed that corrosion occurs when the distance between carbonation front and reinforcement surface (uncarbonated depth) is smaller than 5 mm.As a secondary purpose of this study, it is investigated to examine the interaction between carbonation and chloride penetration and their effects on concrete. This was examined experimentally under various boundary conditions. For concrete under the double condition, the risk of deterioration due to carbonation was not severe. However, it was found that the carbonation of concrete could significantly accelerate chloride penetration. As a result, chloride penetration in combination with carbonation is a serious cause of deterioration of concrete.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회 논문집(II)
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• pp.885-890
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• 2000

12 RC deep beams with a/d = 1.17 are reported. This paper is to study the effect of vertical and horizontal web reinforcement and web reinforcement arrangement on inclined cracking shear, ultimate shear strength, midspan deflection, and inclined crack width. Test results indicated that web reinforcement produces and arrangement seems to moderately affect inclined cracking shear, ultimate shear strength and crack width. However, addition of horizontal web reinforcement(pv = 0.0085) little or no influence on inclined cracking shear, ultimate shear strength and crack width. The member which vertical and horizontal web reinforcement concentrate on the center web considerably increases in load-carrying capacity.

• 한국전문물리치료학회지
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• 제16권4호
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• pp.44-52
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• 2009

It is known that individual factors as cognitive, perception, emotion, and motivation may greatly influence on recovery from neurologic region. This study was to investigate the effects of environmental reinforcement through motivation to perform the tasks voluntarily on motor and cognition function in rats with focal ischemic brain injury. Focal ischemic brain injury was induced in Sprague-Dawley rats (15 rats, $250{\pm}50$ g) through middle cerebral artery occlusion (MCAo). And then, experiment groups were randomly divided into three groups; The control group: MCAo induction ($n_1$=5), the environmental reinforcement (ER) group: the application for ER after MCAo induction ($n_2$=5), the environmental reinforcement through motivation (ERM) group: the application for ERM after MCAo induction ($n_3$=5). The climbing test (CT) and the modified limb placing tests (MLPTs) to measure the motor function and the Morris water maze acquisition test (MWMAT) and the Morris water maze retention test (MWMRT) to measure the cognitive function were performed. For the CT, the ERM group was significantly larger than the ER group. For the MLPTs, the ERM group was significantly decreased compared to other groups. For the MWMAT, the time to find the circular platform in the ERM group significantly decreased compared to other groups. For the MWMRT, the time to dwell on the quadrant circular platform in the ERM group was significantly increased compared to other groups. These results suggested that the ERM could improve the motor and cognitive functions in the rats with focal ischemic brain injury.

• Journal of Korean Biological Nursing Science
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• 제20권2호
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• pp.132-140
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• 2018

Purpose: This study has been carried out in order to develop and verify the effects of self-leadership reinforcement program for hospital nurses. Methods: The research design was a non-equivalent control group pre-posttest design. Participants were 64 individuals (32 in each group), all of whom were nurses working at a university hospital, with less than five years of job experience. Experimental group was provided with two hours of self-leadership reinforcement program, once per week, for four weeks. The questionnaire for pre and post test included general characteristics, transfer motivation for learning, self-leadership, communication ability, clinical nursing competency, organizational commitment, and turnover intentions. Results: There was a significant difference in self-leadership scores between experimental group and control group (F= 15.10, p<.001). There was also a significant difference between the experimental group and the control group in terms of transfer motivation for learning (t = -5.44 p<.001), communication ability (F = 15.29, p<.001), clinical nursing competency (F = 15.23, p<.001), and organizational commitment scores (F = 7.21, p=.009). Conclusion: The self-leadership reinforcement program developed in this study was effective in improving self-leadership, communication ability, clinical nursing competency, and organizational commitment. Thus, by implementing the program at clinical levels, it will be a basis for nursing personnel resource administration.