• Journal of Korea Foundry Society
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• v.12 no.6
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• pp.435-441
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• 1992

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.6
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• pp.105-113
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• 2006

This paper presents the results of an experimental investigation carried out to evaluate the mechanical properties of concrete mixtures in which fine(S) and coarse(G) aggregate was fully replaced with fly ash(FA). And flowability reduction problem in a large amount of fly ash concrete settled addition water($W_f$) in concrete mixture. In the test, water-cement ratio($W_c/C$) was 0.35, 0.45, and water-fly ash ratio($W_f/FA$) was 0.35, 0.45. The fly ash replacement is two different method of P and Q. The P method is mix property that the fly ash and addition water($W_f$) weight is equal to the aggregate weight [ $FA+W_f$ = G (or S)]. The Q method is mix property that fly ash is equal to aggregate weight, and added addition water($W_f$) [$FA+W_f$ > G (or S)]. Test were performed for properties of fresh concrete and compressive strength were determined at 3, 7, 28 and 91 days. The result, compressive strength was improvement that $W_c/C=0.35$, $W_f/FA=0.35$ and fine aggregate replacement in P method series than others. The flowability at Q method was improvement result than P method, but compressive strength was not. Test results indicate significant improvement in the strength properties and flowability of plain concrete by the inclusion of fly ash as fully replacement of fine and coarse aggregate, and can be effectively the fly ash replacement method.

• Journal of applied mathematics & informatics
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• v.40 no.3_4
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• pp.507-513
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• 2022

In this paper, we investigate some results on complex delay-differential equations of the classical Malmquist theorem. A classic illustrations of their results states us that if a complex delay equation w(t + 1) + w(t - 1) = R(t, w) with R(t, w) rational in both arguments admits (concede) a transcendental meromorphic solution of finite order, then deg_wR(t, w) ≤ 2. Development and upgrade of such results are presented in this paper. In addition, Borel exceptional zeros and poles seem to appear in special situations.

• Bulletin of the Korean Mathematical Society
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• v.61 no.1
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• pp.229-246
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• 2024

We consider the delay differential equations $$b(z)w(z+1)+c(z)w(z-1)+a(z)\frac{w'(z)}{w^k(z)}=\frac{P(z, w(z))}{Q(z, w(z))}$$, where k ∈ {1, 2}, a(z), b(z) ≢ 0, c(z) ≢ 0 are rational functions, and P(z, w(z)) and Q(z, w(z)) are polynomials in w(z) with rational coefficients satisfying certain natural conditions regarding their roots. It is shown that if this equation has a non-rational meromorphic solution w with hyper-order ρ2(w) < 1, then either deg_w(P) = deg_w(Q) + 1 ≤ 3 or max{deg_w(P), deg_w(Q)} ≤ 1. In addition, it is shown that in the case max{deg_w(P), deg_w(Q)} = 0 the equations above can have such a solution, with an additional zero density requirement, only if the coefficients of the equation satisfy certain strict conditions.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.3
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• pp.455-459
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• 2001

Tofu (soybean curd) was made with whole soybean flour (WSF, 420 mesh) by various processing conditions of water addition ratio, heating time, coagulation temperature, molding pressure and 0.3% of mixed coagulant (CaSO₄:GDL=50:50(w/w)). Yield content of WSF-tofu was the highest in processing condition of 85℃ coagulation temperature, 10 times water addition, 5min. heating time and 25.00 g/㎠ molding pressure. As the increase of the water addition ratio from 8 to 14 times (water:WSF, v/w), Hunter's L and a values were increased. Raising of heating time (100℃, 1, 5, 10 and 15 min), a and b value were increased. Textural properties of WSF-tofu were significantly affected by coagulation temperature (75, 80, 85 and 90℃). Hardness was increased, but adhesiveness and cohesiveness were decreased. heating time was influenced on harness of WSF-tofu, but water addition ratio was not affected on hardness of WSF-tofu. Increasing of molding pressure (16.83, 25.00, 33.22 and 41.67 g/㎠, 1 hr) was resulted from a increased hardness, gumminess and chewingss of tofu, but adhesiveness was addition ratio, 5 min heating time and 25.00 g/㎠ molding pressure recorded the highest score in sensory evaluation test.

• Journal of the Korean Ceramic Society
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• v.25 no.6
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• pp.571-576
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• 1988

The microstructure and electrical properties of 0.02Pb[Cd1/2W1/2)O3-0.505PbZrO3-0.475PbTiO3 with MnO2 addition have been investigated. The amount of MnO2 addition was 0, 0.2, 0.4, 0.6, 0.8, 1wt%, respectively. When MnO2 is added up to 0.2wt%, Mn3+ which is substituted for Ti4+ site make hole and act as a acceptor. When MnO2 is added over 0.2wt% Mn3+ which is substituted for Cd2+ site create electron and act as a donor. The variation of grain size show that it was rapidly increased by 0.4wt% addition of MnO2, and while that in the range of over 0.6wt% addition of MnO2 it was decreased. The solid solution range of MnO2 that assumed in this composition according to the variations of microstructure and electrical properties was 0.4-0.6wt%.

• Food Science of Animal Resources
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• v.43 no.1
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• pp.25-45
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• 2023

This study evaluated the antibacterial and antioxidant activities of ethanol extract of calamansi pulp (CPE) and its effect on quality and biogenic amine (BAs) formation in pork patties during storage. The CPE were prepared in various conditions (ethanol concentrations of 50%, 70%, and 90% with extraction periods of 3 and 6 days). The extract with potent antibacterial and antioxidant activities (90%, 6 days) was selected for addition to pork patties. Three groups were tested: Control (without extract addition), CPE addition at 0.2% w/w (0.2PCPE), and 0.4% w/w (0.4PCPE). The addition of CPE inhibited the formation of BAs, mainly cadaverine, histamine, and tyramine, in pork patties during storage. The pH and bacterial count of pork patties decreased significantly in a concentration-dependent manner following the addition of CPE. The instrumental color (CIE L^*, CIE a^*, and CIE b^*) tended to be higher in 0.4PCPE than in the control during storage. The thiobarbituric acid reactive substances and volatile basic nitrogen (VBN) values of pork patties were affected by CPE, showing a reduction toward lipid oxidation at any storage period, and maintaining the lowest VBN value in 0.4PCPE at the final storage day. Similarly, the reduction of total BAs in pork patties was observed ranged between 3.4%-38.1% under treatment with 0.2% CPE, whereas 18.4%-51.4% under 0.4% CPE addition, suggesting significant effect of CPE to improve meat quality. These novel findings demonstrate the efficacy of 0.4% CPE as a natural compound to preserve the quality and reduce BAs formation in pork patties during storage.

• Journal of the Korean Applied Science and Technology
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• v.21 no.4
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• pp.279-288
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• 2004

Liquid crystal (LC) system was introduced into W/O emulsion in order to enhance the stability and moisturizing effect. The LC system, composed of beeswax, surfactant, and water was formed on the surface of emulsion droplet, which was investigated through a polarized microscope. The phenomenon that the viscosity in W/O emulsion system is decreased with time, was reduced by the formation of LC with the addition of beeswax. Centrifugal separation test showed that the stability of emulsion system was increased with the addition of beeswax to 3%. The color change of vitamin C was delayed in LC emulsion systems, which indicates stabilization effect against the oxidation of vitamin C. Evaporation rate in W/O emulsion was retarded by LC, so that high moisturizing effect is expected in W/O LC system.

• Korean Journal of Metals and Materials
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• v.56 no.12
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• pp.854-860
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• 2018

In spite of the many attractive properties of (W,Ti)C, its low fracture toughness limits its wide application. To improve the fracture toughness generally a second phase is added to fabricate a nanostructured composite. In this regard, graphene was considered as the reinforcing agent of (W,Ti)C. (W,Ti)C-graphene composites that were sintered within 2 min using pulsed current activated heating under a pressure of 80 MPa. The rapid consolidation method allowed retention of the nano-scale microstructure by blocking the grain growth. The effect of graphene on the hardness and microstructure of the (W,Ti)C-graphene composite was studied using a Vickers hardness tester and FE-SEM. The grain size of (W,Ti)C was reduced remarkably by the addition of graphene. Furthermore, the hardness decreased and the fracture toughness improved with the addition of graphene.

• Food Science and Preservation
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• v.17 no.3
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• pp.334-342
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• 2010

We evaluated the physicochemical and sensory properties of rice cake (Baekseolgi) admixed with various amounts of soybean peel and prepared using a microwave oven. Moisture content decreased gradually during storage but the decrease was less when soybean peel was present, compared with the control material p<0.05). Weight reduction was significantly inhibited as soybean peel level increased. The color lightness $(L^*)$ and redness $(a^*)$ values did not significantly change after addition of soybean peel. However, the yellowness $(b^*)$ value increased uponaddition of soybean peel p<0.05). The RVA properties decreased significantly with the addition of soybean peel, but pasting temperature increased. In terms of texture, neither springiness nor cohesiveness changed upon addition of soybean peel. The hardness, gumminess, and chewiness of Baekseolgi tended to decrease in proportion to the amount of soybean peel added. Adhesiveness rose gradually during storage but the increase was less when soybean peel was added, compared with control. On sensory testing, neither color nor flavor changed upon addition of soybean peel. Baekseolgi with 5% (w/w) soybean peel scored lowest in terms of taste. Hardness score and moisture level were highest when soybean peel was added to 2% or 3% (both w/w). Overall acceptability was greatest when soybean peel was added to 2% (w/w). Thus, Baekseolgi with 2% (w/w) added soybean peal was satisfactory. We conclude that addition of soybean peel to Baekseolgi prepared using a microwave oven improves physicochemical and sensory properties, and delays deterioration during storage.