نتایج جستجو برای: growth ring

تعداد نتایج: 935676  

2015
ASHISH K. SRIVASTAVA

We provide new characterizations of pseudo-Frobenius and quasiFrobenius rings in terms of tight modules. In the process, we also provide fresh perspectives on FGF and CF conjectures. In particular, we propose new natural extensions of these conjectures which connect them with the classical theory of PF rings. Our techniques are mainly based on set-theoretic counting arguments initiated by Osofs...

Journal: :Organic & biomolecular chemistry 2011
Hiroshi Saitoh Takayuki Chida Kenichiro Takagi Kyohei Horie Yoshiyuki Sawai Yuko Nakamura Yoshifumi Harada Kazuya Takenouchi Atsushi Kittaka

In order to obtain vitamin D derivatives, which have strong activity for enhancing bone growth, we designed vitamin D derivatives with various substitutions at the C-2 position. Novel 2 α-substituted vitamin D derivatives were synthesized starting from d-glucose as a chiral template of the A-ring with a CD-ring bromoolefin unit using the Trost coupling method. We evaluated these compounds by tw...

In this paper, we study some ring theoretic properties of the amalgamated duplication ring $Rbowtie I$ of a commutative Noetherian ring $R$ along an ideal $I$ of $R$ which was introduced by D'Anna and Fontana. Indeed, it is determined that when $Rbowtie I$ satisfies Serre's conditions $(R_n)$ and $(S_n)$, and when is a normal ring, a generalized Cohen-Macaulay ring and finally a filter ring.

Journal: :Cancer research 1954
W J BURDETTE

Previous work (1) has shown that the introduc tion of the 1(5@)gl gene, which causes the ring gland to be defective, into a tumor strain of Drosophila results in an increase in the number of tumors in comparison with siblings with normal ring glands. This suggests that the hormone responsible for metamorphosis may account for the usual regres sion of these tumors. Ligation also delays pupation ...

Let R be an associative ring with unity. An element a in R is said to be r-clean if a = e+r, where e is an idempotent and r is a regular (von Neumann) element in R. If every element of R is r-clean, then R is called an r-clean ring. In this paper, we prove that the concepts of clean ring and r-clean ring are equivalent for abelian rings. Further we prove that if 0 and 1 are the only idempotents...

Ahmad Khaled

In the combination of 5-fluorophenyl-1, 3, 7, 9-tetra methylpyrido [2, 3, d, d, 5, 6 dipyrimidine -2, 4, 6, and 8 tetron, there are 4 rings, respectively, ring that is attached to the halogen ring A and, respectively, a ring The lower and the right to the left of the ring A are called C, B, and D. Calculations and studies show that the amount of aromatics in halogen-ring A in all cases has the ...

Journal: :Journal of the Japanese Society of Revegetation Technology 1999

Journal: :Journal of the American Chemical Society 2013
Zheng Yan Yuanyue Liu Jian Lin Zhiwei Peng Gunuk Wang Elvira Pembroke Haiqing Zhou Changsheng Xiang Abdul-Rahman O Raji Errol L G Samuel Ting Yu Boris I Yakobson James M Tour

Precise spatial control of materials is the key capability of engineering their optical, electronic, and mechanical properties. However, growth of graphene on Cu was revealed to be seed-induced two-dimensional (2D) growth, limiting the synthesis of complex graphene spatial structures. In this research, we report the growth of onion ring like three-dimensional (3D) graphene structures, which are...

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