• Journal of the Korea institute for structural maintenance and inspection
• /
• v.17 no.5
• /
• pp.77-86
• /
• 2013

This study investigates the fundamental properties of the water-binder (W/B) ratio and fine aggregate-binder (F/B) ratio in the alkali-activated slag cement (AASC) mortar. The W/B ratios are 0.35, 0.40, 0.45, and 0.50, respectively. And then the F/B ratios varied between 1.00 and 3.00 at a constant increment of 0.25. The alkali activator was an 2M and 4M NaOH. The measured mechanical properties were compared, flow, compressive strength, absorption, ultra sonic velocity, and dry shrinkage. The flow, compressive strength, absorption, ultra sonic velocity and dry shrinkage decreased with increases W/B ratio. The compressive strength decreases with increase F/B ratio at same W/B ratio. Also, at certain value of F/B ratio significant increase in strength is observed. And S2 (river sand 2) had lower physical properties than S1 (river sand 1) due to the fineness modulus. The results of experiments indicated that the mechanical properties of AASC depended on the W/B ratio and F/B ratio. The optimum range for W/B ratios and F/B ratios of AASC is suggested that the F/B ratios by 1.75~2.50 at each W/B ratios. Moreover, the W/(B+F) ratios between 0.13 and 0.14 had a beneficial effect on the design of AASC mortar.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.31 no.4
• /
• pp.403-407
• /
• 1986

The rice leaf color, which was one of main factors to determine application time of fertilizers, was analyzed in visible region, while the distinction of photosynthetic pigments controlling the rice leaf color was separated by T.L.C. The light absorption peaks of ethyl ether extracts of rice leaf blades were occurred in 413, 432, 453 and 662nm. Especially, the maximal light absorption was 432nm in blue and 662nm in red region. The both light absorption ratios (blue to red region) was not greatly different among rice ecotypes, whereas decreasing tendency in increased fertilization was observed. There was a significant negative correlation between the both light absorption ratios and the values of color chart, and the content of chlorophyll in rice leaf blades. The composition ratio of chorophyll was larger than that of carotenoid at heading stage, and the carotenoid was larger than the chlorophyll at 30 days after heading. The composition ratio of chlorophyll among photosynthetic pigments according to rice ecotypes, Japonica x Indica cultivars were larger than Japonica cultivars at heading stage, and Japonica cultivars were larger than Japonica x Indica cultivars at 30 days after heading, while carotene was vice versa.

• Clean Technology
• /
• v.30 no.1
• /
• pp.13-22
• /
• 2024

In this study, blended 6,13-Bis(triisopropylsilylethynyl)pentacene (TP):2-Decyl-7-phenyl[1]benzothieno[3,2-b][1] benzothiophene (BT):Poly styrene (PS) TFT at different ratios were explored for their potential application as light absorption sensors. Due to the mixing of BT, both off current reduction and on/off ratio improvement were achieved at the same time. In particular, the TP:BT:PS (1:0.25:1 w/w) sample showed excellent light absorption characteristics, which proved that it is possible to manufacture a high-performance light absorption device. Through analysis of the crystal structure and electrical properties of the various mixing ratios, it was confirmed that the TP:BT:PS (1:0.25:1 w/w) sample was optimal. The results of this study outline the expected effects of this innovation not only for the development of light absorption devices but also for the development of mixed organic semiconductor (OSC) optoelectronic systems. Through this study, the potential to create a multipurpose platform that overcomes the limitations of using a single OSC and the potential to fabricate a high-performance OSC TFT with a fine-tuned optical response were confirmed.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.33 no.4
• /
• pp.215-224
• /
• 2009

Analysis for various driven nozzle position changes. The analysis was done for different Reynolds number in entrance region of jet-pump and for several diameter ratios of driven nozzle. (1) The largest absorption energy was found at the point s=1 in condition of diameter ratio 1:3.21 and point s=0.5 in condition of diameter ratio 1:2.25. (2) The absorption energy was not related to the change of entrance velocity and the driven nozzle position having the largest absorption energy was function for cross section ratio. (3) As the position of driven nozzle moves to the downstream, the absorption energy gets weaker. Because the energy from swirl was lost at the cross section gets smaller. (4) As the position of driven nozzle moves to the downstream, the injection energy leans to the upper direction wall and as the Reynolds number increase, the lean phenomenon is more distinct. (5) The flow quantity of driven nozzle, the diameter ratio 1:3.21, was 32% higher than that of 1 : 2.25 and as the inlet velocity gets faster the efficiency decreased. And as the cross section of the driven nozzle increases.

• Journal of Powder Materials
• /
• v.15 no.4
• /
• pp.292-296
• /
• 2008

The electromagnetic (EM) wave absorption properties of the $Fe_{73}Si_{16}B_7Nb_3Cu_1$ nanocrystalline powder mixed with 5 to 20 vol% of Ni-Zn ferrites has been investigated in a frequency range from 100MHz to 10GHz. Amorphous ribbons prepared by a planar flow casting process were pulverized and milled after annealing at 425 for 1 hour. The powder was mixed with a ferrite powder at various volume ratios to tape-cast into a 1.0mm thick sheet. Results showed that the EM wave absorption sheet with Ni-Zn ferrite powder reduced complex permittivity due to low dielectric constant of ferrite compared with nanocrystalline powder, while that with 5 vol% of ferrite showed relatively higher imaginary part of permeability. The sheet mixed with 5 vol% ferrite powder showed the best electromagnetic wave absorption properties at high frequency ranges, which resulted from the increased imaginary part of permeability due to reduced eddy current.

• Archives of Pharmacal Research
• /
• v.25 no.3
• /
• pp.387-391
• /
• 2002

The oral absorption and disposition of itraconazole were studied in rats, rabbits and dogs. Serum levels of itraconazole and its active metabolite, hydroxyitraconazole, were determined by a validated HPLC method. The absorption of itraconazole was relatively rapid in rats and dogs but was slower in rabbits. The terminal elimination half-life ($T_{1/2,{\lambda}z}$), time to the peak concentration ($T_{max}$), dose and weight normalized area under the curve (AUC) and the peak concentration ($C_{max}$) of itraconazole found in the dog were comparable to those reported in humans. As in humans, the metabolite to parent drug AUC ratios in rats and dogs were greater than unity but was less in rabbits. The dog appears to be an appropriate animal model while the rat, not the rabbit, may be used as an alternative animal model in predicting the oral absorption of itraconazole in humans.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.14 no.3
• /
• pp.100-107
• /
• 2010

This study evaluates the bond behavior of reinforced concrete (RC) beams using recycled coarse aggregates. A total of four specimens were cast and tested. The test parameter was the type of coarse aggregates, that is, natural and recycled coarse aggregates, and the absorption ratio of recycled coarse aggregate. The recycled coarse aggregates with absorption ratios of 3% and 6% were used in this test. The specimens were simply supported and were subjected to a concentrated load. A test method proposed by Ichinose was adopted to estimate effectively the bond properties of specimens. From the experimental results, it was found that there was no difference of bond characteristics according to the absorption ratio of recycled coarse aggregates.

• Journal of the Korean Wood Science and Technology
• /
• v.24 no.1
• /
• pp.17-26
• /
• 1996

This research was accomplished to evaluate possibility of using paper sludge for the raw materials of wood based panel products. The experimental panels were manufactured by four mixed ratios, the proportion of paper sludge to wood particle: 20:80, 30:70, 40:60, 50:50% (oven dry weight basis) and by three composition types, sludge-particle mixed board, three layered sludge-particle board and three layered particle board. They were tested mechanical (bending strength and internal bond) and physical properties (water absorption, thickness swelling and linear expansion). From the results they were shown that bending strength of mixed and three layered sludge-particle board were decreased with increasing of composition ratios of sludge. And the mechanical and physical properties of the boards of three layered composition types have superior to those of mixed composition type. Although composition ratios of sludge increased, the internal bond strength and dimensional stability of sludge-particle board not decreased quantitatively. We concluded that the mechanical and physical properties of three layered sludge-particle board were similar w those of three layered particle-board (control) made by our laboratory design. Therefore, it was recognized that paper sludge can be used as potential raw material in particle-board manufacturing industry.

• International Journal of Concrete Structures and Materials
• /
• v.10 no.2
• /
• pp.249-256
• /
• 2016

This paper deals with the effects of silica fume content and polymer-binder ratio on the properties of ultrarapid-hardening polymer-modified mortar using silica fume and ethylene-vinyl acetate redispersible polymer powder instead of styrene-butadiene rubber latex to shorten the hardening time. The ultrarapid-hardening polymer-modified mortar was prepared with various silica fume contents and polymer-binder ratios, and tested flexural strength, compressive strength, water absorption, carbonation depth and chloride ion penetration depth. As results, the flexural, compressive and adhesion strengths of the ultrarapid-hardening polymer-modified mortar tended to increase as increasing polymer-binder ratio, and reached the maximums at 4 % of silica fume content. The water absorption, carbonation and chloride ion penetration resistance were improved according to silica fume content and polymer-binder ratio.

• Journal of the Korean Solar Energy Society
• /
• v.25 no.3
• /
• pp.27-35
• /
• 2005

In this paper, a thermodynamic analysis was performed to provide design data for a double-effect absorption heating system with water-LiBr-LiSCN mixture which utilizes solar energy as evaporator heat source. In addition, a comparative study of the water-LiBr-LiSCN mixture against the water-LiBr pair was conducted by a computer simulation. The computer simulation is based on mass, material and heat balance equations for each part of the system. Coefficients of performance and flow ratios for effects of different operating temperatures are investigated. It is found that the heating COP is higher for the water-LiBr-LiSCN mixture than for the water-LiBr pair, and FR is lower for the former.