• Communications of the Korean Mathematical Society
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• v.12 no.4
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• pp.851-854
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• 1997

In this paper we will show that the pure subring R of F-rational ring S is F-rational when R is a one-dimensional ring, or S is a Gorenstein ring. And we will give a condition that a pure subring of an F-rational ring is to be F-rational.

• Journal of applied mathematics & informatics
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• v.42 no.1
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• pp.85-92
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• 2024

In this work we give the necessary and sufficient conditions for f-biharmonic curves in three-dimensional generalized symmetric spaces.

• Bulletin of the Korean Mathematical Society
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• v.59 no.5
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• pp.1237-1246
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• 2022

In this paper, we introduce the concept of N-pure ideal as a generalization of pure ideal. Using this concept, a new and interesting type of rings is presented, we call it a mid ring. Also, we provide new characterizations for von Neumann regular and zero-dimensional rings. Moreover, some results about mp-ring are given. Finally, a characterization for mid rings is provided. Then it is shown that the class of mid rings is strictly between the class of reduced mp-rings (p.f. rings) and the class of mp-rings.

• Bulletin of the Korean Mathematical Society
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• v.50 no.2
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• pp.389-398
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• 2013

Let R be a ring and $\mathcal{Q}$ be a quiver. In this paper we give another definition of purity in the category of quiver representations. Under such definition we prove that the class of all pure injective representations of $\mathcal{Q}$ by R-modules is preenveloping. In case $\mathcal{Q}$ is a left rooted semi-co-barren quiver and R is left Noetherian, we show that every cotorsion flat representation of $\mathcal{Q}$ is pure injective. If, furthermore, R is $n$-perfect and $\mathcal{F}$ is a flat representation $\mathcal{Q}$, then the pure injective dimension of $\mathcal{F}$ is at most $n$.

• The Pure and Applied Mathematics
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• v.27 no.2
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• pp.83-96
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• 2020

In this paper we study Biharmonic curves, Legendre curves and Magnetic curves in three dimensional f-Kenmotsu manifolds. We also study 1-type curves in a three dimensional f-Kenmotsu manifold by using the mean curvature vector field of the curve. As a consequence we obtain for a biharmonic helix in a three dimensional f-Kenmotsu manifold with the curvature κ and the torsion τ, κ² + τ² = -(f² + f'). Also we prove that if a 1-type non-geodesic biharmonic curve γ is helix, then λ = -(f² + f').

• Mycobiology
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• v.34 no.2
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• pp.92-98
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• 2006

A total of 34 species belonging to 21 genera of fungi were recorded on passion fruits of both pure and hybrid origin in Uganda, however, the pure type exhibited wider spectrum (28 species and 16 genera) than the hybrid type (21 & 15). Also, yeasts (unidentified and Rhodotorula mucilaginosa) were also encountered in high numbers. Moreover, the mean count of all mycobiota obtained from the pure type was higher than that of hybrid, despite the bigger size of the later. Members of yeasts and Cladosporium followed by Phoma, Penicillium, Fusarium and Alternaria species dominated on passion fruits of pure origin, while only C. cladosporioides, F. solani and yeasts dominated on the hybrid type. Treatment with Na-hypochlorite exhibited inhibitory effects on the total mycobiotic propagules as well as the dominant species from fruits of both types. The current results, therefore, suggest the use of Na-hypochlorite to control the post-harvest mycobiota associated with passion fruits. Regarding the mycobiota contaminating passion juice, yeasts were found to be the major contaminants with Candida parapsilosis being the most common. Moulds constituted only a minor proportion with Acremonium strictum followed by Fusarium chlamydosporum, F. moniliforme, F. acuminatum and F. solani as the most dominant species. In the heat-treated juice samples, the counts of the most commonly encountered mycobiota (both yeasts and molds) were significantly inhibited or completely eliminated. Some unidentified Bacillus species were also recovered from the juice, however, their counts in the heated samples were increased but insignificantly.

• Kyungpook Mathematical Journal
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• v.53 no.4
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• pp.639-646
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• 2013

We investigate the stability of orthogonally additive set-valued functional equation $$F(x+y)=F(x)+F(y)(x{\perp}y)$$ in Hausdorff topology on closed convex subsets of a Banach space.

• Korean Membrane Journal
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• v.4 no.1
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• pp.20-24
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• 2002

The surface of polysulfone membranes has been modified using the fluorine chemicals, ITFE (2-iodo-1,1,1-trifluoro-ethane F.W.=209.94) and PFPI (1H,1H-pentafluoro-n-propyl iodide F.W.=259.95), and PFI (1H,1H,2H,2H-perfluorohexyl iodide, F.W.=373.99) based on Friedel-Crafts reaction mechanism with varying reaction temperatures, reaction time, and catalysis types. The resulting membranes were characterized through mainly the contact angle measurement and pure water permeability. The smaller reactant shows the larger contact angles. FeBr$_3$ catalyst is more effective than AlCl$_3$. Typically, the PS film treated with ITFE at $25^{\circ}C$ under FeBr$_3$ catalyst showed the contact angle 78.5$^{\circ}C$ which indicated 10% over the value of unreacted PS films. More than 50% of pure water flux 8.0 g/$m^2$hr, reduced at reaction time 10 min relative to the original flux, 3.49 g/$m^2$hr.

• Communications of the Korean Mathematical Society
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• v.36 no.1
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• pp.1-10
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• 2021

Let R and S be two commutative rings, J be an ideal of S and f : R → S be a ring homomorphism. The amalgamation of R and S along J with respect to f, denoted by R ⋈f J, is the special subring of R × S defined by R ⋈f J = {(a, f(a) + j) | a ∈ R, j ∈ J}. In this paper, we study some basic properties of a special kind of R ⋈f J-modules, called the amalgamation of M and N along J with respect to ��, and defined by M ⋈�� JN := {(m, ��(m) + n) | m ∈ M and n ∈ JN}, where �� : M → N is an R-module homomorphism. The new results generalize some known results on the amalgamation of rings and the duplication of a module along an ideal.

• Asian-Australasian Journal of Animal Sciences
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• v.9 no.4
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• pp.461-464
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• 1996

The data on milk yield of 1837 healthy dairy cows of different genetic groups raised in Central Cattle Breeding and Dairy farms, Savar, Dhaka for the period from 1978 to 1992 were analyzed from first to 6th lactation. The mean (SE) milk yields of 100 days, 305 days, total lactation and total life time ($928{\pm}48.6kg$, $2,188{\pm}201.81kg$, $2,661{\pm}385.46kg$ and $11,134{\pm}2,916kg$) respectively, were in pure bred Friesian found to be highest among all genetic groups. The corresponding means in indigenous cows, $334{\pm}12.92kg$, $946{\pm}64.44kg$, $635{\pm}16.31kg$ and $3,934{\pm}402.21kg$ were the lowest. Among the $F_1$, $F_2$ and $F_3$ cross-breds, the $F_1$ half bred Friesian showed the highest performance in milk yield. The half bred Friesian in successive generations yielded low milk. Similar trend was obtained incase of cross-bred with other breeds such as Jersey, Sindhi and Sahiwal. From the over all results, it can be concluded that the performance in respect to milk yield of pure bred Friesian and their $F_1$ half bred with indigenous and Sahiwal were superior over the $F_2$ or $F_3$ cross-breds between Fresian and any other breed irrespective of proportion of blood. The performance in respect to production of indigenous local cow was found to be almost similar with that of Sahiwal breed.