• 한국인쇄학회지
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• 제30권3호
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• pp.35-43
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• 2012

Internal bonding strength of printing paper was increased with sea-algae pulp treatment. Spacially, 9% contents sea-algae pulp treatment in the hardwood pulp are more effective than in the softwood pulp. Most effective mixture ratio of the raw matrials for improvement of the internal bonding strength are softwood pulp 30%, hardwood pulp 70%, sea-algae pulp 9%. Internal bonding strength is effective in more sea-algae pulp contents and softwood pulp contents and wetness.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1999년도 춘계학술대회 논문집
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• pp.383-389
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• 1999

This paper is a study on the improvement effects by quick lime pile through theoretical analysis and in-situ construction test. Effects of strength increase is studied to verify the improvement effects of soft ground arounding quick lime pile. First, engineering characteristics of quick lime and ground was studied, in the second place, laboratory test(consolidation test, triaxial compression test) and in-situ test(portable cone penetration test, vane test) were peformed for verification of strength increase of adjacent ground. Finally, the results of in-situ test were compared with those of theorecal study. From in-situ test results, strength at 28th curing days(6.11-6.55t/㎡) was twice as great as strength before improvement(3.06t/㎡) and was slightly greater than theoretical value(4.95t/㎡).

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2006년도 PAN PACIFIC CONFERENCE vol.2
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• pp.395-400
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• 2006

Polylactic acids polymer (PLA) was applied as an additive to improve the strength properties of handsheets prepared from three unbleached southern pine kraft pulps with different kappa number and an aspen bleached chemithermomechanical pulp (BCTMP). The results showed that PLA could greatly improve the tensile and burst strength of the pulp handsheets. Heat pressing effect was also important to enhance the strength properties. For unbleached kraft pulps, it was found that an appropriate amount of residual lignin in pulps had a positive effect on the handsheets strength improvement when adding PLA. The thickness of the handsheet did not change the PLA strengthening effect. In general, PLA effect on tear strength improvement could be neglected. However, it had a significant effect on the improvement of tear strength for the aspen BCTMP handsheets not containing sufficient amount of fines.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2009년도 춘계 학술논문 발표대회 학계
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• pp.113-117
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• 2009

Fly ash (called FA hereafter) that results from thermal power plants is a long-term strength improving substance with reactivity to pozzolan and has been used for long. However, large amount of FA shows many advantages such as reduction of hydratio energy, long-term improvement in strength and economic feasibility and also has difficulties from reduction in initial strength and durability. In a preceding study, fine particle cement was applied to test the effects on initial strength. Therefore in this study, the effects of fine particle cement on the quality of FA concrete were reviewed. The results can be summarized as follows. Liquidity was increased by the most at FC substitution ratio of 15%. Air capacity was reduced according to increasing substitution ratio of FA and FC. Compressive strength showed high strength expression at all ages when FC was substituted at 45%. Synthesizing the above results, appropriate mixing of FC in FA concrete can improve liquidity, reduce unit quantity and show improvement in strength. In particular, mixed use of FC seems effective in improving early quality of concrete.

• 한국해양공학회지
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• 제18권4호
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• pp.46-51
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• 2004

The surface layer in dredged and reclaimed marine clay is improved by mixing of shallow soils and hardening agents, which is made of cement, containing some other special admixtures. Tests in both laboratory and field settings are performed to investigate the improvement effect and strength properties of cement-stabilized soils. The test results show that the hardening agent sufficiently improves the soil properties of the surface layer, while increasing the load-carrying capacity. The strength of cement-stabilized soils depends, primarily, on water-to-cement ratio and curing temperature. That is, the higher curing temperature and the longer curing time, the higher the strength in cement-stabilized soils. The high ratio of water-ta-cement results in a lower strength.

• The Journal of Korean Physical Therapy
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• 제13권2호
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• pp.273-280
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• 2001

The purpose of this study was to analyze the effect of quadriceps setting exercise(N= 10) and electrical stimulation(N= 10) on improvement of quadriceps muscle strength. The experiment were performed for 6weeks. The subject of this study was 20 college students(male) who had not any medical problems. The quadriceps muscle strength was evaluated by make use of the KIN COM(Isokinetic dynamometer). The electrical stimulator was used to stimulate the quadriceps muscle. The results were as follows: 1. The mean increment ratio was 29.6% for concentric muscle strength and 36.4% for eccentric muscle strength after quadriceps setting exercise(p<0.05). 2. The mean increment ratio was 21.2% for concentric muscle strength and 24.3% for eccentric muscle strength after electrical stimulation, but did not significantly higher than pre-electrical stimulation In this study, we have found that quadriceps setting exercise on left side affect the improvement of the muscle strength in college students(male). However, electrical stimulation did not affect on the muscle strength.

• 한국건축시공학회지
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• 제14권4호
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• pp.322-328
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• 2014

본 연구에서는 콘크리트의 조기강도 확보를 통해 골조공기를 단축하는 것을 목표로 하여 시멘트 종류, 고성능감수제의 감수율, 초기수화 촉진 혼화제의 혼입에 따른 콘크리트의 조기강도 발현성능을 검토하였다. 조기강도 개선형 시멘트와 Sodium persulfate, Potassium hydroxide의 초기수화 촉진물질에 의해 12시간에 5MPa, 18시간에 14MPa의 조기강도를 확보할 수 있는 것으로 나타났다. 이를 통해 건설현장에서 거푸집의 골조공기를 단축시켜 원가절감이 가능할 것으로 기대된다.

• 펄프종이기술
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• 제31권4호
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• pp.69-75
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• 1999

This study was performed to investigated the application of mixed resins for corrugated container board. The corrugated container board yields a sandwich structure in which a linerboard material is glued to a corrugated medium . Now, manufacturing corrugated container boards don't provide sufficient strength, and result in box failure during shipping . Therefore improvement of box strength is necessary . In this study, we intend to improve box strength by improving corrugated medium strength with mixed resins and to find the optimum treatment condition of this resins. First, we tried to mixed resins as Starch+CMC, Starch_Irea, CMC+Urea, Second, investigated to applicability of this resins for corrugated medium , and the third, measured tensile index, burst index, and edgewise compression index on liner, medium paper, and single faced corrugated container board. In this test results, we obtained that the improvement ratios of tensile index in liner and medium paper were approximately 80-185%, 60-118% , respectively. The respecting improvement ratios of edgewise compression index of single faced corrugated container board was approximately 91-124%, relatively. In addition, we concluded that optimum condition in mixing ratio was 1 :3 with CMC + Urea and the ap[plication amounts was 9% on materials. Fro manufacture of corrugated container board, optimum condition in mixing ratio was 1 : 3 with 5% CMC +Urea , because of considering to improvement of strength on cost.

• 한국건축시공학회지
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• 제13권3호
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• pp.227-234
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• 2013

본 연구에서는 3종 조강시멘트에 비해 경제성을 개선하고, 1종 보통포틀랜드시멘트에 비해 조강성능을 개선한 조기강도 개선형 시멘트를 사용한 조강콘크리트의 양생온도 및 물시멘트비에 따른 굳지 않은 콘크리트 특성 및 조기강도 발현 특성을 검토함으로써, 이를 활용한 조강콘크리트의 실용화를 위한 기초자료를 제시하고자 하였다.

• 한국지반환경공학회 논문집
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• 제14권8호
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• pp.5-9
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• 2013

본 연구에서는 저에너지, 친환경적인 방법의 지반개량을 목적으로 하는 유기산재의 지반개량재로서의 강도특성을 모색하였다. 이에 유기산재를 활용하여 재령 28일까지의 일축압축강도시험 및 삼축압축시험을 통한 흙의 강도 변화에 대해 분석하였다. 유기산 재료를 첨가한 점토의 강도는 재령이 길어질수록, 유기산재 혼합비가 커질수록 전반적으로 증가하는 경향을 나타내었다. 유기산계 지반개량재 혼합에 따른 점토의 강도 증진 효과를 파악하는데 있어서, 일축압축강도시험과 삼축압축시험 결과를 통해 유기산재가 지반개량재로 쓰였을 때 가져오는 강도 증대효과가 있다는 것을 알 수 있었다. 결과적으로, 실내시험을 통해 지반개량에 있어 유기산계 지반개량재의 활용가능성을 볼 수 있었다. 향후 세부적인 시험과 현장시험이 좀 더 명확한 강도증진을 규명하는데 도움이 될 것으로 판단된다.