排序方式: 共有18条查询结果,搜索用时 31 毫秒
1.
Adwait K. Pradhan Gadadhar Panda Nrusingha C. Patl Padma L. Nayak 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(2):501-512
The graft copolymerization of methyl methacrylate onto silk fibers initiated by the ferric chloride-eysteine redox system has been investigated in aqueous medium. The rate of grafting was calculated by varying the concentrations of monomer, initiator, acidity of the medium, cysteine, and temperature. The percentage of grafting increases with an increase of Fe3+ concentration up to 2,5 × 10?3 mol/L and thereafter it decreases. The graft yield increases steadily upon increasing the monomer concentration. The graft yield also increases with increasing cysteine concentration up to 0.5 × 10?3 mol/L and then decreases. The effect of the perchloric acid concentration, temperature, solvents, and certain neutral salts on graft yield has also been investigated and a suitable reaction scheme has been proposed. 相似文献
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The results of some investigations into the synthesis and characterization of a new class of oligomers and polymers, the polyselenoacetals, are described. 相似文献
4.
Ronald G. Douglas Gadadhar Misra 《Transactions of the American Mathematical Society》2008,360(4):2229-2264
For any open, connected and bounded set , let be a natural function algebra consisting of functions holomorphic on . Let be a Hilbert module over the algebra and let be the submodule of functions vanishing to order on a hypersurface . Recently the authors have obtained an explicit complete set of unitary invariants for the quotient module in the case of . In this paper, we relate these invariants to familiar notions from complex geometry. We also find a complete set of unitary invariants for the general case. We discuss many concrete examples in this setting. As an application of our equivalence results, we characterise certain homogeneous Hilbert modules over the bi-disc algebra.
5.
Ronald G.?DouglasEmail author Gadadhar?Misra 《Integral Equations and Operator Theory》2003,47(4):435-456
The notion of a quasi-free Hilbert module over a function algebra
$\mathcal{A}$ consisting of holomorphic functions on a bounded domain $\Omega$ in complex m
space is introduced. It is shown that quasi-free Hilbert modules correspond to
the completion of the direct sum of a certain number of copies of the algebra
$\mathcal{A}$. A Hilbert module is said to be weakly regular (respectively, regular) if there
exists a module map from a quasi-free module with dense range (respectively,
onto). A Hilbert module $\mathcal{M}$ is said to be compactly supported if there exists a
constant $\beta$ satisfying $\|\varphi f\| \leq \beta \ |\varphi \| \textsl{X} \|f \|$ for some compact subset X of $\Omega$ and
$\varphi$ in $\mathcal{A}$, f in $\mathcal{M}$. It is shown that if a Hilbert module is compactly supported
then it is weakly regular. The paper identifies several other classes of Hilbert
modules which are weakly regular. In addition, this result is extended to yield
topologically exact resolutions of such modules by quasi-free ones. 相似文献
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This paper surveys the existing literature on homogeneous operators and their relationships with projective representations
ofPS L(2, ℝ) and other Lie groups. It also includes a list of open problems in this area. 相似文献
7.
In this note, we show that a quasi-free Hilbert module R defined over the polydisk algebra with kernel function k(z,w) admits a unique minimal dilation (actually an isometric co-extension) to the Hardy module over the polydisk if and only if S ?1(z, w)k(z, w) is a positive kernel function, where S(z,w) is the Szegö kernel for the polydisk. Moreover, we establish the equivalence of such a factorization of the kernel function and a positivity condition, defined using the hereditary functional calculus, which was introduced earlier by Athavale [8] and Ambrozie, Englis and Müller [2]. An explicit realization of the dilation space is given along with the isometric embedding of the module R in it. The proof works for a wider class of Hilbert modules in which the Hardy module is replaced by more general quasi-free Hilbert modules such as the classical spaces on the polydisk or the unit ball in ? m . Some consequences of this more general result are then explored in the case of several natural function algebras. 相似文献
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Gadadhar Misra 《印度理论与应用数学杂志》2010,41(1):189-197
In this note, we point out that a large family of n×n matrix valued kernel functions defined on the unit disc $
\mathbb{D} \subseteq \mathbb{C}
$
\mathbb{D} \subseteq \mathbb{C}
, which were constructed recently in [9], behave like the familiar Bergman kernel function on $
\mathbb{D}
$
\mathbb{D}
in several different ways. We show that a number of questions involving the multiplication operator on the corresponding
Hilbert space of holomorphic functions on $
\mathbb{D}
$
\mathbb{D}
can be answered using this likeness. 相似文献
10.
For any bounded domain Ω in ?m, let B1(Ω) denote the Cowen-Douglas class of commuting m-tuples of bounded linear operators. For an m-tuple T in the Cowen-Douglas class B1(Ω), let NT (w) denote the restriction of T to the subspace \(\cap^m_{i,j=1}{\rm{ker}}(T_i-w_iI)(T_j-w_jI)\). This commuting m-tuple NT (w) of m + 1 dimensional operators induces a homomorphism \({\rho _{{N_T}\left( w \right)}}\) of the polynomial ring P[z1, · · ·, zm], namely, \({\rho _{{N_T}\left( w \right)}}\) (p) = p(NT (w)), p ∈ P[z1, · · ·, zm]. We study the contractivity and complete contractivity of the homomorphism \({\rho _{{N_T}\left( w \right)}}\). Starting from the homomorphism \({\rho _{{N_T}\left( w \right)}}\), we construct a natural class of homomorphisms \(\rho_{N^{(\lambda)}(w)}\), λ > 0, and relate the properties of \(\rho_{N^{(\lambda)}(w)}\) to those of \({\rho _{{N_T}\left( w \right)}}\). Explicit examples arising from the multiplication operators on the Bergman space of Ω are investigated in detail. Finally, it is shown that contractive properties of \({\rho _{{N_T}\left( w \right)}}\) are equivalent to an inequality for the curvature of the Cowen-Douglas bundle ET. However, we construct examples to show that the contractivity of the homomorphism ρT does not follow, even if \({\rho _{{N_T}\left( w \right)}}\) is contractive for all w in Ω. 相似文献