• 대한조선학회지
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• 제1권1호
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• pp.3-8
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• 1964

The classification society rules [1], [2], [3], [4] on the thicknesses of the bulkhead platings are represented graphically. Fig. 1 shows that every rule value for the thickness of the ordinary watertight bulkhead plating is than theoretical value calculated by Timoshenko's formula (1) for ${\sigma}_y=35,000$ psi and ｋ=0.4998. When a flooding due to damage occurred, however, the stiffened edges would yield and clamped edges would change to plastic hinges. In such case, the maximum bending stress at the clamped edges are reduced considerably. The rule values, therefore, are supposed to be acceptable in spite of their insufficient scantlings compared with the values calculated by (2). In the ordinary watertight bulkhead platings A.B.S. Rules give the largest scantlings of all. Fig. 2 shows that A.B.S. Rules and K.R.-N.K. Rules give larger values than the calculated by (2) for deep tank bulkhead platings. But Lloyd Rules give the smaller thickness than equation (2). The special requirements for corrosion bulkhead platings are not studied here.

• 대한화학회지
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• 제55권6호
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• pp.988-993
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• 2011

Cyclodehydration of 6-amino-5-cyano pyrimidine derivative (2) afforded pyrimidoisoindole derivatives (3). Compound (3) reacted with carbethoxymethylene derivative to give pyridopyrimidine derivatives (5a,b). Compound (3) was also reacted with formamide to give the corresponding pyrimidopyrimdine derivatives (6) that condensed with benzaldehyde to give Schiff's base (7). Refluxing of compound (3) with triethyl orthoformate afforded compound (8) that cyclized with ammonium hydroxide giving the same compound (6). Compound (8) cyclized with hydrazine hydrate giving compound (9) which also cyclized with triethyl orthoformate affording compound (10). Diazotization of compound (3) led to the formation of triazinopyrimidine derivative (11). Cyclization of compound (11) upon treatment with hydrazine hydrate afforded compound (12). Compound (15) was prepared from reaction of compound (3) and ethylenediamine in presence of carbon disulfide. The behaviour of compound (15) toward benzoyl chloride, triethyl orthoformate, nitrous acid and/or carbon disulfide was also described. All proposed structures were supported by elemental analyses, spectroscopic data and some of the new products showed antimicrobial activity.

• 대한전기학회논문지:시스템및제어부문D
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• 제55권9호
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• pp.409-413
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• 2006

In this paper, we propose a new sliding surface design method for a class of uncertain systems with mismatched unstructured uncertainties. The uncertain system under consideration may have mismatched parameter uncertainties in the state matrix as well as in the input matrix. In terms of linear matrix inequalities (LMIs), we give a sufficient condition for the existence of linear sliding surfaces guaranteeing the asymptotic stability of the sliding mode dynamics. And, we give an LMI parameterization of such linear sliding surfaces together with switched feedback control laws. Our LMI condition can be less conservative than the existing conditions and our result supplement the existing results. Finally, we give a numerical example showing that our method can be better than the previous results.

• 품질경영학회지
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• 제14권2호
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• pp.47-54
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• 1986

A different kind of approximation has been developed in connection with calculation of the normal family distributions in digital computer. These approximations usually employ polynomial expressions. They give quite high accuracy, sometimes only within definite limits on the values of the variable. Outside these limits they may give quite poor approximations. In this paper we compare these approximations by criteria of C.P.U. time and accuracy using micro computer. Approximation formulas given by Zelen and Severo (1984) are proven to give the most accurate results within allowable C.P.U. time.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제12권4호
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• pp.275-287
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• 2005

Geometric invariants are basic tools for geometric processing and computer vision. In this paper, we give a linear approximation for the differentiation of the binormal vector field of a space curve by using the forward and backward differences of discrete binormal vectors. Two kind of discrete torsion, say, back-ward torsion $T_b$ and forward torsion $T_f$ can be defined by the dot product of the (backward and forward) discrete differentiation of binormal vectors that are linear approximations of torsion. Using Frenet formula and Taylor series expansion, we give error estimations for the discrete torsions. We also give numerical tests for a curve. Notably the average of $T_b$ and $T_f$ looks more stable in errors.

• Bulletin of the Korean Chemical Society
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• 제12권1호
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• pp.26-31
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• 1991

Facile and efficient syntheses of terpenic perfumeries cis-jasmone, dihydrojasmone, and tetrahydrojasmone have been investigated. Cis-jasmone was synthesized by successive metallation followed by alkylation of acetone N,N-dimethylhydrazone with (Z)-2-penten-1-yl tosylate (or 2-pentyn-1-yl tosylate) and propylene oxide in one flask to give a ketonic alcohol, which was oxidized to the corresponding diketone, followed by base-catalyzed intramolecular aldol condensation to give a regioselective cyclization product. Dihydrojasmone and tetrahydrojasmone could be conveniently obtained from 2-octanone. The dimethylhydrazone of the ketone was lithiated with butyllithium and reacted with propylene oxide to give a ketonic alcohol, which was oxidized to a diketone, followed by base-catalyzed intramolecular cyclization to afford dihydrojasmone. Tetrahydrojasmone was prepared by converting the ketonic alcohol into corresponding iodoketone, followed by base-catalyzed intramolecular cycloalkylation to furnish an odoriferous product.

• 약학회지
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• 제47권1호
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• pp.1-4
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• 2003

In order to search the new serotonin bioisoster, 2-(5,6-dimethoxy-l-indenyl)ethyl amine(1) was synthesized. 3,4-Dimethoxybenzaldehyde, as starting material, was condensed with malonic acid in the presence of pyridine and piperidine to form 3,4-dimethoxycinnamic acid(2). Compound 2 was performed catalytic hydrogenation with 10％ Pd-C to give propanoic acid derivative 3, which was cyclized by Friedel-Crafts acylation to afford 5,6-dimethoxyindan-l-one(4). Compound 4 was reduced with NaBH$_4$ in ethanol to obtain l-indanol 5, and it was dehydrated to give 5,6-dimethoxy-l-indene(6). This compound was lithiated with 2.5M n-butyllithium and reacted with 1,2-dibromoethane to give 2-(5,6-dimethoxy-l-indenyl)ethyl bromide(7), and which was treated with anhydrous ammonia to synthesize compound 1.

• Bulletin of the Korean Chemical Society
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• 제13권2호
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• pp.176-179
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• 1992

New method for preparing cyclopentanediol from bicyclic ketal is described. Bicyclic ketal is cleaved to give 1,5-diketone, which is then reductively coupled intramolecularly to yield 1,2-cyclopentanediol. A solution of bicyclic ketal (1a) in methylene chloride was treated with aluminum chloride(2 eq.)-sodium iodide(l.5 eq.) at ambient temperature for 3 h to give the 1,5-diketone (2a) in 71% yield after basic work-up followed by short path column chromatography. A solution of the 1,5-diketone (2a) in THF was reacted with titanium tetrachloride(6 eq.)-Mg(Hg)(0.3 eq.) at $0^{\circ}C$ for 4 h to give the 1,2-cyclopentanediol (3a) in 75% yield after basic work-up followed by short path column chromatography.

• Bulletin of the Korean Chemical Society
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• 제9권6호
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• pp.349-352
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• 1988

[(Benzene)Mn$(CO)_3$]$^+$ reacts with NaP(O) (OR)$_2$ (R = Me, Et, Ph) to give the phosphonate compound 1. Compound 1 reacts with R'Li (R = Me, Ph, $^nBu, ^tBu$) to yield the isomerized compound 2 and the alkylated compound 3. [(Toluene)Mn$(CO)_3$]$^+$ reacts with NaP(O)$(OMe)_2$ to give the phosphonate complexes 1-A and 1-B. Treatment of 1-A with $^tBuLi$ in THF affords complexes 3-A and 3-B with the later major. With 1-B only the complex 3-C is formed. [(Anisole)Mn$(CO)_3$]$^+$ reacts with NaP(O)$(OMe)_2$ to give the phosphate complex 1-C, which on treatment with $^tBuLi$ and then $H_2O$ yields compound 3-D. After demetallation of compound 3-D, meta-tertbutyl-anisole is obtained in a reasonable yield.

• Kyungpook Mathematical Journal
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• 제62권3호
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• pp.407-423
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• 2022

In this paper, we determine the structure of rings that have secondary representation (called representable rings) and give some characterizations of these rings. Also, we characterize Artinian rings in terms of representable rings. Then we introduce completely representable modules, modules every non-zero submodule of which have secondary representation, and give some necessary and sufficient conditions for a module to be completely representable. Finally, we define strongly representable modules and give some conditions under which representable module is strongly representable.