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991.
N. Munichandraiah L. G. Scanlon R. A. Marsh B. Kumar A. K. Sircar 《Journal of Applied Electrochemistry》1995,25(9):857-863
A composite polymer electrolyte of polyethyleneoxide-LiBF4 containing fine particles of zeolite was studied using electrochemical impedance spectroscopy, cyclic voltammetry, differential scanning calorimetry, infrared spectroscopy and scanning electron microscopy. When compared with the polymer electrolyte without zeolite, the specific conductivity of the composite electrolyte film is higher by about two orders of magnitude at room temperature. The increase in specific conductivity is explained as due to increased amorphocity which is reflected in the thermal studies. The nature of the cyclic voltammograms and infrared spectra is discussed.Part of this work was presented at the Electrochemical Society Meeting, Honolulu, Hawai (May 1993). 相似文献
992.
993.
994.
Oligonucleotide (ODN) directed triplex formation has therapeutic importance and depends on Hoogsteen hydrogen bonds between a duplex DNA and a third strand. While T*A:T triplets are formed at neutral pH, C+*G:C are favoured at acidic pH. Herein it is shown that 18-mer ODN containing spermine conjugated to 5-Me-dC at N4 (1-5), form triplexes with complementary 24-mer duplex 8:9 at neutral pH (7.3, 100 mM NaCl). Under such conditions, control ODN's carrying dC (6) or 5-Me-dC (7) did not show any triple helix formation. Remarkably, the triplexes from spermine-conjugates (1-5) have foremost stability at neutral pH (7.1), unlike the behavior of normal ODN's where optimal stability is at acidic pH (5.5). These results have importance in designing oligonucleotides for antigene applications. 相似文献
995.
This paper explains the development and implementation of a new methodology for expanding existing computer networks. Expansion is achieved by adding new communication links and computer nodes such that reliability measures of the network are optimized within specified constraints. A genetic algorithm-based computer network expansion methodology (GANE) is developed to optimize a specified objective function (reliability measure) under a given set of network constraints. This technique is very powerful because the same approach can be extended to solve different types of problems; the only modification required is the objective function evaluation module. The versatility of the genetic algorithm is illustrated by applying it to solve various network expansion problems (optimize diameter, average distance and computer network reliability for network expansion). The results are compared with the optimal solutions computed using an exhaustive search of complete solution space. The results demonstrate that GANE is very effective (in both accuracy and computation time) and applies to a wide range of problems, but it does not guarantee the optimal results for every problem 相似文献
996.
997.
Recently scientists have investigated what statistical distributions can be used to describe the distribution of the number
of authors per article.Ajiferuke has undertaken the most comprehensive study of this problem. He has found that by and large the Inverse Gaussian-Poisson
distribution could describe most properly the observed authorship distributions. However, it is well known that this distribution
is rather intricate, soRousseau tried to fit some simple one-parameter distributions to the number of authors of LIS articles. He has found that the geometric
and the truncated Poisson distribution adequately describe these authorship data sets. The main purpose of the present paper
is to continue these investigations and to analyse and test the viability of simple statistical distributions. As to (sub)fields
where the single author dominates the results ofRousseau were corroborated: the truncated Poisson and the geometric distribution give often adequate fits to describe the number of
authors. The Lotka distribution should be rejected. The truncated binomial distribution and the truncated negative binomial
were investigated as well. However, it is not clear whether they are acceptable candidates. 相似文献
998.
JB Van Liew PJ Davis FB Davis LL Bernardis MR Deziel LN Marinucci D Kumar 《Canadian Metallurgical Quarterly》1993,48(5):B184-B190
We studied the relationships of plasma glucose, fructosamine, triglycerides, and cholesterol as a function of age, gender, and diet in barrier-raised Fischer 344 rats aged 5 to 26 months, fed a diet either ad libitum or restricted to 60% of the ad libitum caloric intake. The complex relationships of these plasma levels to age, gender, and diet led to the development of a model with age, diet, and sex as covariates. Overall, fasting plasma glucose concentrations were reduced by approximately 25% in rats on the restricted diet, compared to ad libitum-fed animals. There was a significant age-dependent decline in glucose levels in male animals, whereas in females there was an increase in plasma glucose with aging. Plasma fructosamine levels in calorie-restricted animals, overall, were reduced by 7% compared to levels in animals fed ad libitum. There was a significant positive correlation between plasma glucose and fructosamine levels. Mean plasma triglyceride content was decreased by 50% in calorie-restricted rats compared to ad libitum-fed animals. A significant decrease in triglyceride levels with increasing age was seen in male animals, and an increase with aging in females. There was a significant positive correlation between plasma glucose and triglyceride levels. Plasma cholesterol levels in calorie-restricted animals were reduced by 7% compared to levels in ad libitum-fed animals. An increase of cholesterol concentration with aging was significant in both males and females. Analysis of the data showed that there were significant differences between male and female Fischer 344 rats in the response of plasma glucose and fructosamine to aging and calorie restriction. Changes of plasma triglyceride and cholesterol with aging and dietary calorie restriction were also different in males and females. Studies of the effect of aging on glycemia and blood lipid content should take into account the contributions of animal sex. 相似文献
999.
We study the problem of how to minimize the cost of maintaining consistency among at least N copies of an object in an enviroment where the mix of read and write operations can vary. Quorum consensus requires that
read and write operations must assemble appropriate quorums before an operation can succeed. The cost of an operation is proportional
to the size of a quorum, and the objective is obviously to minimize the cost while still maintaining consistency. It is known
that the quorum size can be reduced by organizing a number of copies into logical structures such as grids and hierarchies.
In this paper, we show (a) how methods based on grids and hierarchies can be treated in a common framework, and (b) how these
hierarchies can be optimized so as to minimize the cost of consensus. Of course, the optimal solution depends upon the mix
of read and write operations that is present. Consequently, given N copies of an object and a ratio of write operations F, our algorithms determine the optimal values for the number of levels
in the hierarchy and the read/write quorum sizes at each level. The algorithms, which run in O(N
1.63) and O(N
2) time, were tested, and the results are reported and discussed.
Received September 1, 1992/February 16, 1995 相似文献
1000.
C Prabhakar G Madhusudhan K Sahadev CM Reddy MR Sarma GO Reddy R Chakrabarti CS Rao TD Kumar R Rajagopalan 《Canadian Metallurgical Quarterly》1998,8(19):2725-2730
Novel compounds having a dual pharmacophore were synthesised and evaluated for their insulin sensitiser and anti-inflammatory properties in different animal models. 相似文献