• Magazine of the Korean Society of Agricultural Engineers
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• v.30 no.3
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• pp.106-113
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• 1988

This study was performed to obtain the basic data which can be applied to use of foamihg mortars. 1. At the mixing ratio 1:1, the highest strengths were showed by foaming mortam, respec - tively. But, it. gradually was decreased in poorer mixing ratio and more addition of foam- ing agent. The decreasing rates of strengths were incresed in poorer mixing ratio and more addition of foaming agent. 2. The strengths were decreased up to 77.0-92.8% by mix-foaming type and 36.7-74.4% by pre-foamed type than cement mortar. 3. At the mixing ratio of 1:1, the lowest air contents were showed by foaming mortars, respectively. But, it gradually was increased in poorer mixing ratio and more addition of foaming agent. The increasing rates of air contents were increased in richer mixing ratio and more addition of foaming agent. 4. Air contents were showed up to 26.0-63.8 times by mix-foaming type and 5.8-17.7 times by pre-foamed type than cement mortar, respectively. 5. The correlations between compressive strength and air content were highly significant, respectively. The multiple regression equations of strengths and air content were computed depending on a fuction of mixing ratio and addition of foarning agent. It was highly significant, respectively.

• Bulletin of the Korean Chemical Society
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• v.24 no.2
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• pp.193-196
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• 2003

Nucleophilic addition reactions of benzylamines $(XC_6H_4CH_2NH_2)$ to benzylidene Meldrum's acids (BMA; $YC_6H_4CH=C(COO)_2C(CH_3)_2$) have been investigated in acetonitrile at 20.0 ℃. The rates of addition are greatly enhanced due to the abnormally high acidity of Meldrum's acid. The magnitudes of the Hammett $({\rho}_X\;and\;{\rho}_Y)$ and Bronsted $({\rho}_X$)$ coefficients are rather small suggesting an early transition state. The sign and magnitude of the cross-interaction constant, ${\rho}_{XY}$ (= -0.33), and kinetic isotope effects $(k_H/k_D\;{\stackrel}{~}{=}\;1.5-1.7)$ involving deuterated benzylamine nucleophilies $(XC_6H_4CH_2ND_2)$ are indicative of hydrogen-bonded cyclic transition state. The activation parameters, ${\Delta}H^{\neq}\;{\stackrel}{~}{=}\;4\;kcal\;mol^{-1}\;and\;{\Delta}S^{\neq}\;{\stackrel}{~}{=}\;-37\;e.u.$, are also in line with the proposed mechanism.

• Journal of Food Hygiene and Safety
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• v.38 no.1
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• pp.19-25
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• 2023

Addition of spice for inhibition of bacterial growth in ground chicken meat was investigated. The ground chicken meat approximately contained 72.98±0.15% moisture, 23.37±0.46% crude protein, 1.00±0.03% crude fat, and 1.90±0.03% ashes. Addition of rosemary showed the maximum bacterial inhibition, followed by garlic and mustard. The inhibitory effect increased with the addition of a greater quantity of spices. The optimal added concentration of spices for inhibition of total viable cell and proliferation of Escherichia coli in ground chicken meat was 2%, 4%, and 1.2% for rosemary, garlic, and mustard, respectively. The growth inhibition of total viable cells and E. coli differed during storage period for MixA (97.4%) > rosemary (96.9%) > MixB (96.3%) > garlic (53.7%) > mustard (33.3%). The addition of sterilized garlic to ground chicken meat showed that the total viable cells was low at 2.6-3.0 log CFU/g on the 0-day and 2.4-3.2 log CFU/g on the 9-day, and the number decreased as the storage lengthened. Non-sterilized garlic treatment showed a higher number of total viable cells than the control group, and this increased with elapse of storage time. The number of E. coli, was low at 0.4-1.0 log CFU/g on the 0-day and 0.5-1.5 log CFU/g on the 9-day for the sterilized group, and the change during the storage showed a similar trend for the total viable cells. In conclusion, the microbial safety of ground chicken meat products was improved by various mixed applications of rosemary, garlic, and mustard.

• Journal of the Korean Ceramic Society
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• v.24 no.6
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• pp.537-542
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• 1987

The microstructure and electrical properties of Pb[(Sb1/2 Nb1/2)0.08 Zr0.49 Ti0.48]O3 with MnO2 addition have been investigated in this work. The amount of MnO2 addition was 0, 0.4, 0.8, 1.2, 2.0 wt%, respectively. The soild solution range of MnO2 that assumed in this composition according to thevariations of micro-structure and electrical properties was 0.4-0.8 wt%.

• Journal of the Korean Ceramic Society
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• v.31 no.11
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• pp.1337-1345
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• 1994

Glasses in the system of 45CaO-25TiO2-30P2O5 containing 1 mole% of M2O(M=Li, Na, K) were melted and crystallized. And their crystal phases were Ca3(PO4)2, CaTi4(PO4)6, and TiO2. Porous glass-ceramics with skeleton of two crystal phase CaTi4(PO4)6 and TiO2 were prepared by selective leaching of Ca3(PO4)2 with 0.1 N-HCl. Glass transition temperature(Tg) and crystallization temperature(Tc) were decreased by addition of 1 mole% alkali metal oxide. Pore size of porous glass-ceramics was increased with increasing heat treatment temperature and its dependence on heat treatment temperature was decreased with addition of Na2O and K2O. It was found that porous glass-ceramics of parent glass and containing 1mole% M2O(M=Li, Na, K) composition had maximum specific surface area, porosity and maximum of crystallzed phase by heat treatment at 80$0^{\circ}C$, 76$0^{\circ}C$, 78$0^{\circ}C$, 80$0^{\circ}C$ respectively.

• Journal of the Korean Magnetics Society
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• v.11 no.1
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• pp.14-20
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• 2001

The structure, shape, size, and magnetic properties of Ni$_{0.5}$Cu$_{0.1}$Zn$_{0.4}$Fe$_2$O$_4$ have been investigated as a function of annealing temperatures. In order to control the microwave absorbing properties of ferrite-rubber composite and the complex losses (magnetic loss and conduction loss), the effect of carbon addition was also studied. It was found that the coercive force decreased with increasing heat-treatment temperatures. Relative complex permeability and reflection loss were measured by the network analyzer. As a result, the natural resonance occurred in the low frequency tinge, and the matching frequency of the ferrite-rubber composite prepared at 130$0^{\circ}C$ was found to be lower. As heat-treatment temperatures were increased, the magnetic loss ($\mu$$_{r}$", $\mu$$_{r}$′) and the dielectric loss ($\varepsilon$$_{r}$"/$\varepsilon$$_{r}$′) were increased. It was caused that the absorption characteristics of the absorber were improved. The conduction loss and magnetic loss were expected to be occurred together because two matching frequencies were shown with carbon addition. It was confirmed that the matching frequency of the microwave absorber could be controlled by controlling heat-treatment temperatures and carbon additions.ons.tions.

• Journal of The Korean Society of Grassland and Forage Science
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• v.10 no.1
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• pp.48-54
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• 1990

In order to investigate effects of starch addition on the fermentative quality and dry matter digestibility (DMD) of Kudzu, Puerarie thunbergii Bentham plants were ensiled by the conventional method in small experimental plastic silo of 7.5 liter with different levels of starch addition. The fermentative quality, neutral detergent fiber (NDF), acid detergent fiber (ADF), and acid detergent lignin (ADL) of silage were determined by chemical analysis, and in vitro dry matter digestibility (DMD) by pepsin-cellulase technique. Total digestibile nutrients (TDN), digestible energy (DE) and metabolizable energy (ME) were calculated with DMD. The results obtained were as follows; 1. Acetate, butyrate, PH, NDF, ADF, and ADL of Kudzu silage were reduced with increasing of starch addition but the contents of lactate and total acid were increased. 2. The DMD was marked 47.5, 49.5, 51.2, 57.9 and 62.0 % under starch addition with a rate of 0, 2, 4, 6 and 8 %, respectively. 3. TDN, DF and ME were increased with high rate of starch addition. 4. The regression equation and correlation of Kudzu silage between level of starch (X) and DMD (Y) were Y= 41.6 + 1.86 X (I= 0.96, P < 0.01), of silage between Flieg's score (X) and DMD (Y) were Y= 41.6 + 0.23 X (I= 0.96, P < 0.01) and of silage between level of starch (X) and Flieg's score (Y) were Y= 21.3 + 7.97 X (I= 0.97, P < 0.01), respectively.

• Korean Chemical Engineering Research
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• v.58 no.4
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• pp.658-664
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• 2020

Zeolite HY is wet impregnated with Ni (0.1, 0.3, 0.4, 0.5 wt%), Pt (0.1 wt%) and reduced in presence of hydrogen to form nanosized particles of Ni and Pt. All the catalysts were characterized by XRD, TEM, ESCA, NH₃-TPD, Pyridine adsorbed FT-IR and BET. Characterization results confirm that the Ni and Pt fractions effectively rehabilitated the physio-chemical properties of the zeolite HY catalysts. Further, all the reduced catalyst were screened with hydroisomerization of m-xylene at LHSV = 2.0 h^-1 in the temperature range 250-400 ℃ in steps of 50 ℃ in hydrogen atmosphere (20 ml/g). The addition of Ni to Pt catalyst increases hydroisomerization conversion, as well as maximizes p-xylene selectivity by restricting the pore size. The increasing trend in activity continues up to 0.3 wt% of Ni and 0.1 wt% Pt addition over zeolite HY. The increasing addition of Ni increases the total number of active metallic sites to exposed, which increases the metallic sites/acid sites ratio towards the optimum value for these reactions by better balance of synergic effect for stable activity. The rate of deactivation is pronounced on monometallic catalysts. The results confirm the threshold Ni addition is highly suitable for hydroisomerization reaction for product selectivity over Ni-Pt bimetallic/support catalysts.

• Journal of the Korean Applied Science and Technology
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• v.4 no.1
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• pp.19-22
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• 1987

To investigate the protective action of various antioxidants on the photooxidation of rice bran oil, it was irradiated with red and visible light in presence and absence antioxidants with or without sensitizer (methylene blue). 1. Rice bran oil with and without sensitizer in chloroform-ethanol (4:1, v/v) media was largely oxidized under visible light irradiation. on the other hand, rice bran oil without sensitizer was hardly oxidized under red light irradiation. 2. Rice bran oil with sensitizer was oxidized much faster than that without. And the absorbance of it irradiated with visible was increased more than that with red light. 3. The effectiveness of antioxidants on the rice bran oil photooxidation was same order as follows: Irradiation with visible light, no addition of sensitizer ${\beta}$-carotene > dl-{$\alpha}$-tocopherol > BHT > BHA Irradiation with visible light, addition of sensitizer ${\beta}$-carotene > BHT > dl-${\alpha}$tocopherol > BHA Irradiation with red light, addition of sensitizer ${\beta}$-carotene > BHA > BHT > dl-${\alpha}$-tocopherol From these results, we concluded that rice bran oil was largely oxidized under visible light irradiation, therefore it must be protected from photooxidative deterioration by the addition of antioxidants.

• The Korean Journal of Ecology
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• v.27 no.3
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• pp.155-159
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• 2004

In order to gain a better understanding of how forests participate in the cycling of carbon, effects of nitrogen addition on soil respiration were investigated on the oak forest in Kongju, Korea. Study site was divided into control, treatment f and treatment 2 plots, with 5 replication in each plot. In each replicate of treatment 1 and treatment 2 were fertilized with ammonium nitrate (NH$_4$NO$_3$), 30 g/$m^2$ and 60 g/$m^2$, respectively. Soil respiration, soil temperature, ammonium-N and nitrate-N were measured during the experimental period. Ammonium-N and nitrate-N in Ta were higher than those in control and T$_1$. Ammonium-N and nitrate-N in top-soil and sub-soil decreased sharply in August after bi9 rainfall in July in T$_1$ and T$_2$, however, those in control plot increased. Soil respiration in T$_2$ Plot showed consistently higher than those in control and T$_1$ until the end of July. However, soil respiration was similar among the control, T$_1$ and T$_2$ in mid-August and September The amount of Co$_2$ released from soil respiration in control, T$_1$ and T$_2$ in mid-August was 8.0$\pm$0.4, 9.3$\pm$0.6 and 10.2$\pm$0.5 $\mu$mol$^{-1}$ ㆍm$^{-2}$ ㆍs$^{-1}$ , respectively. However, those in control, T$_1$ and T$_2$in mid-August was 13.0$\pm$0.4, 13.5$\pm$0.5, 13.3$\pm$0.6 $\mu$mol$^{-1}$ ㆍm$^{-2}$ ㆍ$^{-1}$ , respectively. The results suggest that nitrogen addition in this oak forest has a positive effect on soil respiration.