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121.
The optimized geometries, complexation energies, etc. of HXPY (X?=?Al, B; Y?=?H, F, OH) donor–acceptor complexes have been investigated at the B3LYP/6-311+G(d,p), MP2/6-311+G(d,p) and/or CCSD(T)/6-311+G(d,p) levels. The results show that HBPY (Y?=?H, F, OH) is more stable than the corresponding HAlPY (Y?=?H, F, OH), F (or OH) substitution on phosphorus results in decreasing complex stability, and the stronger the electron-attracting nature of the substitution atom, the more stable the complex. Moreover, the thermodynamic and kinetic properties of the formation reaction of these donor–acceptor complexes were also examined within the temperature range 200–800?K using the general statistical thermodynamics and Eyring transition state theory with Wigner correction. It is concluded that the formation of HBPY is thermodynamically favoured over that of the corresponding HAlPY, especially at low temperature, and is kinetically favoured over that of the relevant HAlPY (Y?=?H, F, OH), especially at high temperature. 相似文献
122.
Joseph K. Rugutt Nikolaus H. Fischer Marcus A. Nauman Thomas J. Schmidt Dana K. Berner 《光谱学快报》2013,46(5):799-818
The two known cadinanes 2-hydroxy-8α-hydroxycalamenene and 2-hydroxy-8α-angeloyloxycalamenene were isolated from a Louisiana population of Heterotheca subaxillaris. Their 13C NMR spectra were fully assigned by the application of HETCOR, COLOC, COSY, NOESY and DEPT experiments. It was shown on the basis of NOESY experiments that both cadinanes require revision at the stereogenic centre C-7. 相似文献
123.
ABSTRACT The interaction between phenformin hydrochloride and bovine serum albumin (BSA) was investigated by the methods of chemiluminescence combined with equilibrium dialysis technique. A novel N-bromosuccinimide (NBS)–eosin Y (EY) chemiluminescence (CL) method was established for the determination of phenformin. The mechanism of this chemiluminescence system was proposed. Optimization studies were performed to determine the phenformin. Under the optimal conditions, the CL intensity was linear for a phenformin concentration over the range of 4.6 × 10?8 to 5.0 × 10?5 g/mL. The detection limit was 1.5 × 10?8 g/mL. The data obtained by the present equilibrium dialysis–CL system were analyzed using the Klotz plot and the Scatchard analysis. The results showed that the Klotz plot and the Scatchard plot are linear with good correlation coefficient, indicating that the phenformin has only one type of binding site on BSA. The binding parameters were the number of the binding sites n (1.02) and the estimated association constant K (2.66 × 104 L/mol). The chemiluminescence system combined with equilibrium dialysis developed in this work demonstrated its use for determination of interaction between drug and protein by using relatively simple instrument. 相似文献
124.
偏最小二乘分光光度法同时测定镍基合金中的铈和钇 总被引:6,自引:3,他引:3
以对乙酰基偶氮氯膦(CPApA)为显色剂,研究了同时测定Ce和Y的最佳条件,由于二者吸收光谱严重重叠,本文运用偏最小二乘法实现了Ce和Y的同时测定,结果满意。 相似文献
125.
Chun JIN Yin Juan JIA Bin Bin FAN Jing Hong MA Rui Feng LI 《中国化学快报》2006,17(3):419-422
In the last decade, encapsulation of transition metal complexes in zeolites and related materials has been paid much attention, because this type of materials could serve as functional mimic enzymes, possessing both homogeneous-catalysis and heterogeneous… 相似文献
126.
Miodrag ?ivkovi? 《Linear algebra and its applications》2006,414(1):310-346
Denote by An the set of square (0, 1) matrices of order n. The set An, n ? 8, is partitioned into row/column permutation equivalence classes enabling derivation of various facts by simple counting. For example, the number of regular (0, 1) matrices of order 8 is 10160459763342013440. Let Dn, Sn denote the set of absolute determinant values and Smith normal forms of matrices from An. Denote by an the smallest integer not in Dn. The sets D9 and S9 are obtained; especially, a9 = 103. The lower bounds for an, 10 ? n ? 19 (exceeding the known lower bound an ? 2fn − 1, where fn is nth Fibonacci number) are obtained. Row/permutation equivalence classes of An correspond to bipartite graphs with n black and n white vertices, and so the other applications of the classification are possible. 相似文献
127.
Achim Kehrein 《Journal of Pure and Applied Algebra》2006,205(2):279-295
This paper presents several algorithms that compute border bases of a zero-dimensional ideal. The first relates to the FGLM algorithm as it uses a linear basis transformation. In particular, it is able to compute border bases that do not contain a reduced Gröbner basis. The second algorithm is based on a generic algorithm by Bernard Mourrain originally designed for computing an ideal basis that need not be a border basis. Our fully detailed algorithm computes a border basis of a zero-dimensional ideal from a given set of generators. To obtain concrete instructions we appeal to a degree-compatible term ordering σ and hence compute a border basis that contains the reduced σ-Gröbner basis. We show an example in which this computation actually has advantages over Buchberger's algorithm. Moreover, we formulate and prove two optimizations of the Border Basis Algorithm which reduce the dimensions of the linear algebra subproblems. 相似文献
128.
Wavelet sparse approximate inverse preconditioners 总被引:1,自引:0,他引:1
We show how to use wavelet compression ideas to improve the performance of approximate inverse preconditioners. Our main idea
is to first transform the inverse of the coefficient matrix into a wavelet basis, before applying standard approximate inverse
techniques. In this process, smoothness in the entries ofA
−1 are converted into small wavelet coefficients, thus allowing a more efficient approximate inverse approximation. We shall
justify theoretically and numerically that our approach is effective for matrices with smooth inverses.
Supported by grants from ONR: ONR-N00014-92-J-1890, and the Army Research Office: DAAL-03-91-C-0047 (Univ. of Tenn. subcontract
ORA4466.04 Amendment 1 and 2). The first and the third author also acknowledge support from RIACS/NASA Ames NAS 2-96027 and
the Alfred P. Sloan Foundation as Doctoral Dissertation Fellows, respectively.
the work was supported by the Natural Sciences and Engineering Research Council of Canada, the Information Technology Research
Centre (which is funded by the Province of Ontario), and RIACS/NASA Ames NAS 2-96027. 相似文献
129.
Complex symmetric matrices often appear in quantum physics in the solution methods of partial differential equations such as the Schrödinger equation. We have recently introduced a new fast and efficient direct eigensolver for this problem in [4], and reported its performance in the eigenvalue calculation in [3]. In this paper, we further report on some benchmark tests for computing the full and partial eigenspectrum on a variety of super computing machines, i.e., the Cray J-932, the DEC Alfa 8400, and the SGI Power Challenge 8000 and 10000. We observe that in all cases the new algorithm is much faster than codes available in standard state of the art eigensolver packages such as LAPACK. 相似文献
130.