• 대한수학회보
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• 제49권4호
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• pp.761-765
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• 2012

We prove that for a toric manifold (respectively, a quasitoric manifold) M, any graded ring isomorphism $H^*(M){\rightarrow}H^*({\Pi}_{i=1}^{m}\mathbb{C}P^{ni})$ can be realized by a diffeomorphism (respectively, a homeomorphism) ${\Pi}_{i=1}^{m}\mathbb{C}P^{ni}{\rightarrow}M$.

• 대한치과보철학회지
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• 제20권1호
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• pp.75-81
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• 1982

The purpose of this study was to compare the marginal fitness between Ni-Cr alloy and type III gold alloy, according to two finishing line, chamfer and shoulder. As experimental materials, author selected type III gold alloy and Ni-Cr alloy (Hicrown) which were popularly used in Korea for the full cast crown. Author prepared the wax patterns with milled stainless steel die and ring. The wax patterns were invested, burnouted, and casted. The maginal discrepancy was measured with scanning electron microscope. Author obtained the following results from this study. 1. The maginal fitness of Type III gold alloy was not significantly different from that of Ni-Cr alloy (Hi-crown). 2. There is no significant difference between chamfer and shoulder in case of Type III gold alloy. 3. The maginal fitness of chamfer type is significantly superior to that of shoulder type in the Ni-Cr alloy (Hi-Crown).

• Kyungpook Mathematical Journal
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• 제59권4호
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• pp.603-615
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• 2019

Let R be an associative unital ring with an endomorphism α and α-derivation δ. The constant products of elements in Ore extension rings, when the coefficient ring is reversible, is investigated. We show that if f(x) = ∑ⁿ_i=0 a_ixⁱ and g(x) = ∑^m_j=0 b_jx^j be nonzero elements in Ore extension ring R[x; α, δ] such that g(x)f(x) = c ∈ R, then there exist non-zero elements r, a ∈ R such that rf(x) = ac, when R is an (α, δ)-compatible ring which is reversible. Among applications, we give an exact characterization of the unit elements in R[x; α, δ], when the coeficient ring R is (α, δ)-compatible. Furthermore, it is shown that if R is a weakly 2-primal ring which is (α, δ)-compatible, then J(R[x; α, δ]) = N iℓ(R)[x; α, δ]. Some other applications and examples of rings with this property are given, with an emphasis on certain classes of NI rings. As a consequence we obtain generalizations of the many results in the literature. As the final part of the paper we construct examples of rings that explain the limitations of the results obtained and support our main results.

• 대한화학회지
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• 제33권5호
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• pp.510-515
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• 1989

테트라에틸렌펜타아민과 포름알데히드의 주형축합반응으로부터 새로운 펜타아자 거대두고리 리간드인 1,3,6,9,12-펜타아자비시클로[10,2,1]펜타데칸(D)의 니켈(II) 및 구리(II) 착화합물 $[Ni(D)]^{2+},\;[Cu(d)]6{2+}\;그리고\;[Cu(D)Cl]^+$를 합성하였다. 거대두고리 리간드인 D에는 한 개의 이미다졸리딘 고리가 있다. $[Ni(D)]^{2+}와 [Cu(D)]^{2+}$는 5-5-5-6 킬레이트고리 배열로 된 평면사각형 구조를 이루며, 5-배위 착이온인 $[Cu(D)Cl]^+$의 구조는 그의 전자스펙트럼으로 볼 때 사각피라미드일 것으로 보인다. 이들 니켈(II) 및 구리(II) 착화합물의 합성과 확인 그리고 분광학적인 특성과 화학적인 특성이 논의된다.

• 대한화학회지
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• 제35권1호
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• pp.46-50
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• 1991

니켈(II) 이온 존재하에서 isonitrosobenzoylacetone 과 diamine(ethylenediamine 및 propylenediamine)을 반응시켜 새로운 금속착물들을 합성하고 이들 착물의 구조를 조사하였다. 그 결과 Ni((IBN)$_2$-en((IBA)$_2$-en=N,N'-ethylenebis(isonitrosobenzoylacetone imino))착물에서 리간드의 두 isonitroso기(=N-O) 중에서 한 =N-O는 질소원자를 통하여 금속에 배위되어 5각형 고리를 이루고, 다른 =N-O는 산소원자를 통하여 금속에 배위되어 6각형 고리를 이루고 있다. 그러나 Ni(IBN)$_2$-pn((IBA)$_2$-pn=N,N'-propylenebis(isonitrosobenzoylacetone imino))착물에서 리간드의 두 isonitroso기(=N-O) 모두 질소원자를 통하여 금속에 배위되어 5각형 고리를 이루고 있다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.847-851
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• 2000

In this study, contour-vibration-mode Pb($Ni_{1/2}$,$W_{1/2}$)$O_3$-Pb(Zr,Ti)$O_3$ piezoelectric transformers for driving a 28W(T5) fluorescent lamp were fabricated to the modified filter structure with ring and dot electrodes which has been developed for application in 455kHz AM radios. The piezoelectric transformers were fabricated to the size of $31.5$\times$31.5$\times$2.5$mm^3$ with the variations of ring/dot electrode area ratio. Driving of piezoelectric transformer was carried out with input region for the ring electrode and output region for the dot electrode. The electrical properties and characteristic temperature rises caused by the vibration were measured at various load resistances. A 28 W fluorescent lamp, T5, was successfully driven by the fabricated transformer. The transformer with ring/dot electrode area ratio of 1.83 exhibited the best properties in terms of output power, efficiency and characteristic temperature rise, 30.95 W, 97.57% and8.3$^{\circ}C$ respectively.

• 대한화학회지
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• 제16권2호
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• pp.84-92
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• 1972

A mechanism for the ring formation of nickel phthalocyanine (Ni-Pc) has been proposed based on chemical kinetics. The effect of the catalyst on the rate was examined, and ammonium molybdate has been found to be the most effective. The reaction order of the ring formation was determined to be of the 1st order over all, with only the concentration of urea affecting the rate of the ring formation. All the results including thermodynamic parameters support a conclusion that the rate-determining step seems to be the enolization of the urea-catalyst transition complex, followed by fast decomposition of the tautomeric enolized urea into ammonia and isocyanic acid. These intermediates then reacted with the phthalic anhydride to form imino and diimino-phthalimide, which condense to form nickel phthalocyanine in the presence of the nickel cation.

• Bulletin of the Korean Chemical Society
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• 제22권12호
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• pp.1316-1322
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• 2001

Transition metal complexes of novel mono- and di-ferrocene-substituted porphyrins have been synthesized and characterized by structural and electrochemical methods. The X-ray structures of Mn(FPTTP)Cl and Mn(DFTTP)Cl showed the distorted square pyramidal coordination geometry with syn configuration of chloride and ferrocenyl substituents. The electrochemistry of ferrocene-substituted porphyrins and their metal complexes has been determined to elucidate the ${\pi}-conjugation$ effect of the porphyrin ring. The ferrocenyl group of H2FPTTP underwent a reversible one-electron transfer process at 0.30 V, indicating the good electron donating effect of the phorphyrin ring to the ferrocene substituent. The redox potential of the ferrocenyl subunit and porphyrin ring was affected by the central metal ions of the metalloporphyrins, that is, Zn(II) and Ni(II) made the oxidation of ferrocene much easier and Mn(III) made it harder. The ferrocene subunits of H2DFTTP interacted electrochemically with each other with peak splitting of 0.21 V. The strength of the electrochemical interactions between the two ferrocenyl substituents can be controlled by central metal ions of metalloporphyrins.

• Bulletin of the Korean Chemical Society
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• 제12권2호
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• pp.219-224
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• 1991

New binuclear Ni(Ⅱ) and Cu(Ⅱ) complexes with various alkyl derivatives of 1,2-bis(1,3,6,8,10,13-hexaaza-1-cyclotetradecyl) ethane, in which two fully saturated 14-membered hexaaza macrocyclic subunits are linked together by an ethylene chain, have been synthesized by the one step template condensations of formaldehyde with ethylenediamine and appropriate primary alkyl amines in the presence of the metal ions. Each macrocyclic subunit of the double-ring macrocyclic complexes contains one alkyl pendant arm and has a square planar geometry with a 5-6-5-6 chelate ring sequence. The visible spectra and oxidation properties indicate that the metal-metal interaction of the binuclear complexes are not significant. Synthesis, characterization, and the properties of the complexes are presented.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2003년도 somma/kms meeting
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• pp.233-233
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• 2003