• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.38 no.4
• /
• pp.257-264
• /
• 2005

We studied age and growth of the sea urchin, Pseudocentrotus depressus, to obtain some informations regarding its sustainable production and appropriate resources reinforcement. The samples were collected at two locations (Ongpo and Bubhwan) in Jeju, Korea. Annual rings were formed from October to January, and this period was well matched with the time just prior to or during their reproduction. Two population regression lines generated by using Walford's plotting with mean radius of each age group showed significant differences in their growth rate between the two sampling locations (p<0.0l). When the regression equations were calculated using either madreporite's radius (R) and test diameter (L) or body weight (W) and test diameter (L), the results were L=23.830+ 11.735R and $W=0.0004L^3$, and no statistically significant differences were detected between the two populations (p>0.2). Based on the data of madreporite's radius and test diameters, two estimated growth equations were $L_t(mm)=72.988(1-e^{-0.412(t-0.596)}\;and\;L_t(mm)=70.195(1-e{-0.365(t-0.51l)}$ in Ongpo and Bubhwan population, respectively. Three distinct annulus groups were recognizable within the distribution of the radii of the annual rings measured from age I to age 5. The mean radii calculated from the same annulus group were all identical even though they were from different age groups.

• Journal of applied mathematics & informatics
• /
• v.25 no.1_2
• /
• pp.551-562
• /
• 2007

This paper concerns a relationship between rough sets, intuitionistic fuzzy sets and ring theory. We consider a ring as a universal set and we assume that the knowledge about objects is restricted by an intuitionistic fuzzy ideal. We apply the notion of intutionistic fuzzy ideal of a ring for definitions of the lower and upper approximations in a ring. Some properties of the lower and upper approximations are investigated.

• Bulletin of the Korean Mathematical Society
• /
• v.36 no.3
• /
• pp.599-608
• /
• 1999

$H_v$-rings first were introduced by Vougiouklis in 1990. Then Darafsheh and the present author defined the $H_v$-ring of fractions $S_{-1}R$ of a commutative hyperring. The largest class of multivalued systems satisfying the module-like axioms is the Hv-module. In this paper we define $H_v$-module of fractions of a hypermodule. Some interesting results concerning this $H_v$-module is proved.

• Kyungpook Mathematical Journal
• /
• v.45 no.1
• /
• pp.131-135
• /
• 2005

Let an integral domain R be locally polynomial over an integral domain D and let R be a content module over D. We show that if D is a PVMD, then $$Cl_t(R){\sim_=}Cl_t(D)$$. This generalizes the polynomial case. We also show that R is a PVMD if and only if D is a PVMD if and only if $R_{N_v}$ is a PVMD.

• Proceedings of the Korean Institute of Industrial Safety Conference
• /
• 2001.11a
• /
• pp.111-117
• /
• 2001

The problem of the vibration of arches has become a subject of interest for many investigators due to Its importance in many practical applications. The early investigators into the in-plane vibration of rings were Hoppe $^{1)}$ and Love $^{2)}$ . Love $^{2)}$ improved on Hoppe's theory by allowing for stretching of the ring. Lamb $^{3)}$ investigated the statics of incomplete ring with various boundary conditions and the dynamics of an incomplete free-free ring of small curvature.(omitted)

• 한국정보디스플레이학회:학술대회논문집
• /
• 2008.10a
• /
• pp.975-978
• /
• 2008

Novel sulfur-containing aromatic compounds were developed as stable, high-performance organic semiconductors for OTFT applications. Of them, dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DNTT) consisting of six aromatic rings gave high quality thin films by vapor deposition, which acted as a superior FET channel showing FET mobility as high as $3.0\;cm^2V^{-1}s^{-1}$. On the other hand, highly soluble 2,7-dialkyl[1]benzothieno[3,2-b][1]benzothiophenes ($C_n$-BTBTs) gave solution-processible OTFTs with FET mobility higher than $1.0\;cm^2V^{-1}s^{-1}$.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.35 no.6
• /
• pp.557-562
• /
• 2002

This study was to estimate population growth parameters of the freshwater bivalve, Corbicula (Corbiculina) papyacca (Heude) in Korea. Samples were collected from Jojong stream in Chungpyeong from September 1999 to August 2000. Ages were determined from the ring of shell, The shell length of the samples ranged from 4,2 mm to 28.1 mm, The ring on the surface of shell was formed once a year from January to March, Marginal increment analysis of shell rings indicated that annuli were formed in June. Spawning period was estimated to be May to August with a peak between June and July through fatness analysis, and thus rings were considered to be true annual marks. Von Bertalanffy's growth parameter were estimated from a nonlinear method with the value of logical maximum shell length ($L_{propto}$) was 34,36 mm, K was 0.1531/year, logical age of shell length 0 ($t_{0}$) was -0,5246 year, and logical maximum total weight ($W_{propto}$) was 11.42 g.

• Bulletin of the Korean Mathematical Society
• /
• v.42 no.4
• /
• pp.679-690
• /
• 2005

Let K be a commutative ring with unity, R a prime K-algebra of characteristic different from 2, d a non-zero derivation of R, I a non-zero right ideal of R, f($x_1,{\cdots},\;x_n$) a multilinear polynomial in n non-commuting variables over K, a $\in$ R. Supppose that, for any $x_1,{\cdots},\;x_n\;\in\;I,\;a[d(f(x_1,{\cdots},\;x_n)),\;f(x_1,{\cdots},\;x_n)]$ = 0. If $[f(x_1,{\cdots},\;x_n),\;x_{n+1}]x_{n+2}$ is not an identity for I and $$S_4(I,\;I,\;I,\;I)\;I\;\neq\;0$$, then aI = ad(I) = 0.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.2
• /
• pp.600-608
• /
• 2013

Amide analogs of tridecapeptide ${\alpha}$-factor (WHWLQLKPGQPMYCONH$_2$) of Saccharomyces cerevisiae, in which Trp at position 1 and 3 were replaced with other residues, were synthesized to ascertain whether cooperative interactions between two Trp residues occurred upon binding with its receptor. Analogs containing Ala or Aib at position 3 of the peptide $[Ala_3]{\alpha}$-factor amide (2) and $[Aib_3]{\alpha}$-factor amide (5) exhibited greater decreases in bioactivity than analogs with same residue at position one $[Ala^1]{\alpha}$-factor amide (1) and $[Aib^1]{\alpha}$-factor amide (4), reflecting that $Trp^3$ may plays more important role than $Trp^1$ for agonist activity. Analogs containing Ala or Aib in both position one and three 3, 6 exhibited complete loss of bioactivity, emphasizing both the essential role and the combined role of two indole rings for triggering cell signaling. In contrast, double substituted analog with D-Trp in both positions 9 exhibited greater activity than single substituted analog with D-Trp 8 or deleted analog 7, reflecting the combined contribution of two tryptophane residues of ${\alpha}$-factor ligand to activation of Ste2p through interaction with residue $Tyr^{266}$ and importance of the proper parallel orientation of two indole rings for efficient triggering of signal G protein coupled activation. Among ten amide analogs, $[Ala^{1,3}]{\alpha}$-factor amide (3), $[Aib^{1,3}]{\alpha}$-factor amide (6), [D-$Trp^3]{\alpha}$-factor amide (8) and [des-$Trp^1,Phe^3]{\alpha}$-factor amide (10) were found to have antagonistic activity. Analogs 3 and 6 showed greater antagonistic activity than analogs 8 and 10.

• Bulletin of the Korean Chemical Society
• /
• v.16 no.6
• /
• pp.539-542
• /
• 1995

The crystal structure of K92-X (K92Al92Si100O384), a=25.128(1) Å, dehydrated at 360 ℃ and 2X 10-6 Torr, has been determined by single-crystal X-ray diffraction techniques in the cubic space group Fd&bar{3} at 21(1) ℃. The structure was refined to the final error indices R1=0.044 and Rw=0.039 with 242 reflections for which I<3σ(I). In this structure, ninety-two K+ ions are located at the five different crystallographic sites. Sixteen K+ ions are located at the centers of the double six rings (site I; K(1)-O(3)=2.65(2) Å and O(3)-K(1)-O(3)=92.0(6)°). About twelve K+ ions lie at site I' in the sodalite cavity opposite double six rings (D6R's) and these K+ ions are recessed ca. 1.62 Å into the sodalite cavity from their O(3) plane (K(2)-O(3)=2.74(2) Å, O(3)-K(2)-O(3)=88.5(8)°). About thirty-two K+ ions are located at the site II in the supercage and these K+ ions are recessed ca. 1.20 Å into the supercage from their O(2) plane (K(3)-O(2)=2.64(2) Å, and O(2)-K(3)-O(2)=101(1)°). About twenty-two K+ ions lie at the site III in the supercage opposite 4-ring ladder and the remaining ten K+ ions lie at the site III' near the 4-ring ladder in the supercage (K(4)-O(4)=2.88(3) Å, O(4)-K(4)-O(4)=79.8(9)°, K(5)-O(4)=2.8(2) Å, and O(4)-K(5)-O(4)=68(5)°).