• Kyungpook Mathematical Journal
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• v.46 no.4
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• pp.603-613
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• 2006

Near-rings considered are right near-rings and R is a near-ring. $J_0^r(R)$, the right Jacobson radical of R of type-0, was introduced and studied by the present authors. In this paper $J_1^r(R)$ and $J_2^r(R)$, the right Jacobson radicals of R of type-1 and type-2 are introduced. It is proved that both $J_1^r$ and $J_2^r$ are radicals for near-rings and $J_0^r(R){\subseteq}J_1^r(R){\subseteq}J_2^r(R)$. Unlike the left Jacobson radical classes, the right Jacobson radical class of type-2 contains $M_0(G)$ for many of the finite groups G. Depending on the structure of G, $M_0(G)$ belongs to different right Jacobson radical classes of near-rings. Also unlike left Jacobson-type radicals, the constant part of R is contained in every right 1-modular (2-modular) right ideal of R. For any family of near-rings $R_i$, $i{\in}I$, $J_{\nu}^r({\oplus}_{i{\in}I}R_i)={\oplus}_{i{\in}I}J_{\nu}^r(R_i)$, ${\nu}{\in}\{1,2\}$. Moreover, under certain conditions, for an invariant subnear-ring S of a d.g. near-ring R it is shown that $J_2^r(S)=S{\cap}J_2^r(R)$.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.5
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• pp.735-741
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• 1999

The effects of supplementation with nitrogen molasses mineral blocks and molasses urea mix during and immediately prior to the dry season on the production of dairy cows were studied on-station and on-farm near Morogoro, Tanzania. Supplementation of blocks to on-station cows also receiving ad libitum grass hay and 6 kg/d of maize bran increased milk production from 6.7 L/d to 11.2 L/d (p<0.05), increased dry matter intake from 10.1 kg/d to 12.0 kg/d (p<0.05), but did not significantly affect milk composition, intake of hay, and live weight changes. This increase in milk yield is mainly explained by increased intakes of energy and nitrogen. Supplementation with the molasses urea mix increased daily milk yield from 6.7 L/d to 8.8 L/d (p<0.05), but did not significantly affect the other measured production parameters. The on-farm supplementation of the blocks increased daily milk yield by 1.5 L/d in the dry season (p<0.05). This supplementation did not increase milk yields prior to the dry season, since quality forage was still available. Taking the production costs into account, supplementation with the blocks and supplementation with mix were cost effective if milk yields increased by 0.7 L/d. Hence supplementation with blocks and supplementation with mix were effective on-station, and supplementation with blocks was cost effective on-farm during the dry season.

• Journal of the Korean Chemical Society
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• v.17 no.2
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• pp.73-79
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• 1973

The ultrasonic absorption of Dodecyl pyridinium bromide (D.P.B.) in aqueous solution has been measured at $20^{\circ}C$ over a range of frequencies between 0.1 mc and 90 mc and a range of concentrations from 5 to 100 mM. The excess absorption was observed only in the solutions the concentration of which was higher than the critical micellar concentration (c.m.c.) both in the presence and absence of salt. The excess absorption of sound and the relaxation frequencies obtained from the absorption curves show a discontinuity with the variation of the concentration of D.P.B. in the neighborhood of 60 mM. Other properties such as viscosity, conductivity and velocity of sound also exhibit such a change near the same concentration. It is concluded that a change in the properties of the micelles of D.P.B. occurs in the neighborhood of this concentration. The mechanism of the observed ultrasonic excess absorption in attributed to the reaction $M_2{\rightleftarrow}M_1+2Br^-$where$M_2$ and$M_1$are two types of micelles. The rate constants of forward and backward reactions are found to be $6.9 {\times} 10^5 sec^{-1)$and $6.7{\times}10^{10}sec^{-1}mole{-2}$ respectively. Some kinetic characteristics including free energy, enthalpy, entropy and activation energy were calculated.

• Journal of Soil and Groundwater Environment
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• v.22 no.6
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• pp.1-11
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• 2017

This study was conducted to investigate the performance of four commercial chemical agents in stabilizing arsenic (As) in soil at the forest area near the former Janghang smelter site. After amending the stabilizing agents (A, B, C, and D) into As-contaminated soil samples, synthetic precipitation leaching procedure (SPLP) and solubility bioavailability research consortium (SBRC)-extractable As concentrations significantly decreased except for agent D, which is mainly composed of fly ash and calcium carbonate. Increase of SPLP and SBRC-extractable As concentrations in four soil samples (S1, S2, S3, and J2) was attributed to desorption of As adsorbed on iron oxides due to high pH generated by agent D. It is therefore necessary to consider application conditions according to soil characteristics such as pH and buffering capacity. Results of sequential extraction showed that readily extractable fractions of As in soil (i.e., sum of $SO_4-$ and $PO_4-extractable$ As in soil) were converted into non-readily extractable fractions by amending agents A, B, and C. Such changes in the As distribution in soil resulted in the decrease of SPLP and SBRC-extractable As concentration. A series of follow-up monitoring and management plan has been suggested to assess the longevity of the stabilization treatments in the site.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.2
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• pp.163-170
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• 1992

Color of kimchi juice was measured instrumentally to evaluate the quality of Korean cabbage kimchi during fermentation at 4$^{\circ}C$ and 16$^{\circ}C$ . These results were compared with those of chemical analyses of kimchi juice and sensory evaluation for kimchi. Chemiral analyses and sensory evaluation showed that the kimchi has reached pH 4.3, the pH value under an optimum ripening period, after 3-days fermentation at 16$^{\circ}C$ with almost the highest contents of vitamin C and carotenoids as well as desirable sour taste and texture. At 4$^{\circ}C$ the kimchi was unripened after 6-days fermentation. At 16$^{\circ}C$, $L^{*}$ value of kimchi juice did not show any significant change during fermentation periods. However, $a^{*}$ value increased until day 4$^{\circ}C$ and thereafter decreased sharply. $b^{*}$ value increased until day 3 and then showed no change. High correlations were seen between volume of kimchi juice, pH, total acidity and $L^{*}$or $b^{*}$ value, and between carotenoid content and $a^{*}$ value, respectively. It was desirable to use color $a^{*}$ or $b^{*}$ value of kimchi juice to evaluate the quality of kimchi. The kimchi was under an over-ripening period when $a^{*}$ value was equal to or lower than the initial value, or when $b^{*}$ value was almost constant. Predicting an optimum ripening period was possible by using a proportional value of $a^{*/}$ $b^{*}$ , i.e., unripening period, 1 $\geq$ and near 1 ; optimum ripening period, near 0.8 ; over-ripening period, < 0.8.eriod, < 0.8.d, < 0.8.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.30 no.6
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• pp.467-478
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• 2019

This paper describes the development and measurement results of a wide-band planar active phase array antenna system for an electronic warfare jamming transmitter. The system is designed as an $8{\times}8$ triangular lattice array using a $45^{\circ}$ slant wide-band antenna. The 64-element transmission channel is composed of a wide-band gallium nitride(GaN) solid state power amplifier and a gallium arsenide(GaAs) multi-function core chip(MFC). Each GaAs MFC includes a true-time delay circuit to avoid a wide-band beam squint, a digital attenuator, and a GaAs drive amplifier to electronically steer the transmitted beam over a ${\pm}45^{\circ}$ azimuth angle and ${\pm}25^{\circ}$ elevation angle scan. Measurement of the transmitted beam pattern is conducted using a near-field measurement facility. The EIRP of the designed system, which is 9.8 dB more than the target EIRP performance(P), and the ${\pm}45^{\circ}$ azimuth and ${\pm}25^{\circ}$ elevation beam steering fulfill the desired specifications.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.1
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• pp.1-8
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• 2010

To investigate the effects of sediments on the water quality of an estuary reservoir, Asan reservoir, we analyzed physical and chemical characteristics of the sediments and estimated nutrients release rate from the sediments. The sediments characterized as sandy loam are mainly composed of Nonapatite-P(64.7%) which has strong influence on the eutrophication of the reservoir by releasing from the sediments under the condition of increasing pH and anaerobic environment. High nutrient release rates was observed in April. Negative release rates in June show that there is no significant nutrient release from the sediments. The nutrient release was active at the Site B around the confluence of tributary compared to the Site A near the embankment. Based on the information of nutrient release rates and sediments surface area, daily average nutrient release rates of Asan reservoir are estimated; TN 6,609 kg/d, TP 3,877 kg/d. Since the amount of N and P released from the sediments corresponds to the 7.06% of N and 22.04% of P incoming from the watershed, it can be concluded that there is little influence of sediments on the water quality of Asan reservoir.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.1049-1052
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• 2004

In general, contrary to the CRTs with impulsive emission, liquid crystal displays have motion artifacts such as blurring. ghost image, decrease of dynamic CR(contrast ratio), and stroboscopic motion due to hold type driving method. In this paper, to improve motion picture quality of LCDs. impulsive driving method of black data insertion was applied to the OCB mode which is well known for its fast LC response time and wide viewing angle properties. Subject evaluation was carried out with CRT, TN, SIPS(Super IPS). and impulsive driving OCB. Moving picture image quality near CRT was obtained in impulsive OCB driving mode

• Annals of Occupational and Environmental Medicine
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• v.34
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• pp.38.1-38.9
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• 2022

Background: This study investigated the risk perceptions, prevalence of environmental diseases (EDs) and associated factors with the prevalence of environmental disease among the population living near an incinerator Methods: Study area were divided into 3 local areas near the incinerator by distance (A, B, C) and control area (D) by distance and geographic isolation. A Questionnaire was conducted with 1,380 in local residents (A, B, C) and 390 in control area (D), gathered information of demographic characteristics, lifestyle, perception of damage by incinerators, experience of EDs (atopic dermatitis, allergic rhinitis, asthma) diagnosed by physician. Analysis of variance, χ² test, and Kruskal Wallis test was applied to determine the difference by area. Logistic regression analysis was performed to identify factors associated with the prevalence of allergic rhinitis. Results: Residents residing closer to the incinerator had negative perception in most items in questionnaire compared with control. The prevalence of allergic rhinitis was higher as they lived nearby the incinerator (p = 0.008). The associated factors with the prevalence of allergic rhinitis were carpet (odds ratio [OR]: 1.79, p = 0.001), residential area (marginally significant), duration of residence (OR: 1.09, p < 0.001). The perception of environmental pollution around the residential area was inversely associated with the prevalence of allergic rhinitis: perceived as very dissatisfied (OR: 4.21, p = 0.02) compared with very satisfied. Conclusions: As closer to the incinerator, the risk perception tend to negative and prevalence of EDs were increased. Carpet, residential area, duration of residence and perception of environmental air pollution around the residential area were associated with prevalence of allergic rhinitis. These results may be useful for the communication with residents to discuss the environmental problems caused by the incinerator.

• Nuclear Engineering and Technology
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• v.54 no.4
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• pp.1482-1494
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• 2022

Power conversion cycles (Subcritical Steam, Supercritical Steam, Open Air Brayton, Recuperated Air Brayton, Combined Cycle, Closed Brayton Supercritical CO₂ (sCO₂), and Stirling) are evaluated for land-based nuclear microreactors based on technical maturity, system efficiency, size, cost and maintainability, safety implications, and siting considerations. Based upon these criteria, Air Brayton systems were selected for further evaluation. A brief history of the development and applications of Brayton power systems is given, followed by a description of how these thermal-to-electrical energy conversion systems might be integrated with a nuclear microreactor. Modeling is performed for optimized cycles operating at 3 MW(e) with turbine inlet temperatures of 500 ℃, 650 ℃ and 850 ℃, corresponding to: a) sodium fast, b) molten salt or heat pipe, and c) helium or sodium thermal reactors, coupled with three types of Brayton power conversion units (PCUs): 1) simple open-cycle gas turbine, 2) recuperated open-cycle gas turbine, and 3) recuperated and intercooled open-cycle gas turbine. Aeroderivative turboshaft engines employing the simple Brayton cycle and two industrial gas turbine engines employing recuperated air Brayton cycles are also analyzed. These engines offer mature technology that can facilitate near-term deployment with a modest improvement in efficiency.