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101.
The composite of silver-modified lithium manganese oxide were prepared using thermal decomposition method of different mole
ratio. Structural characterization was carried out by X-ray diffraction (XRD). XRD analysis revealed different patterns as
the content of the dopant in the spinel increases. Phase analysis shows that Ag particles were dispersed on the LiMn2O4 surface instead of entering the spinel structure. On the other hand, the electrochemical behavior of cathode powder was examined
by using two-electrode test cells consisting of a cathode, metallic lithium as anode, and a solid polymer electrolyte of 0.87PEO-0.13LiCF3SO3-0.10DBP. According to the electrochemical tests results, the influence of the Ag additive content on the electrochemical
properties of Ag/LiMn2O4 composites is clearly shown. 相似文献
102.
103.
104.
This paper is a study of part of the Algebra Project's program for underrepresented high school students from the lowest quartile of academic achievement, social and economic status. The study focuses on students’ learning the concept of function. The curriculum and pedagogy are part of an innovative, experimental approach designed and implemented by the Algebra Project. The instructional treatment took place over 7 weeks during the Junior Year of 15 students from our target population. Immediately after instruction, a written instrument was administered followed, several weeks later, by in-depth interviews. The results are that many of our participants achieved a level of knowledge and understanding of functions on a par with beginning college students, including preservice teachers, as reported in the literature. Many conceptual difficulties that have been reported in the research literature were not as prevalent for our participants and some of them were capable of solving difficult problems involving composition of functions. We conclude that, with appropriate pedagogy, it is possible for students in the Algebra Project's target population to learn substantial and non-trivial mathematics at the high school level, and that the Algebra Project approach is one example of such a pedagogy. 相似文献
105.
The analog of Posner's theorem on the composition of two derivations in prime rings is proved for 3-prime near-rings. It is shown that if d is a nonzero derivation of a 2-torsionfree 3-prime near-ring N and an element a ? N is such that axd = xda for all x ? N, then a is a central element. As a consequence it is shown that if d\ and d2 are nonzero derivations of a 2-torsionfree 3-prime near-ring N and xd1yd2 = yd2xd1 for all x, y ? N, then N is a commutative ring. Thus two theorems of Herstein are generalized 相似文献
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107.
Relationships between the orthogonal direct sum decomposition of a vector space over a finite field and the existence of the generalized inverses of a linear transformation over the finite field are analyzed. Necessary and sufficient conditions for judging the existence of the generalized inverses of a linear transformation over a finite field are presented. 相似文献
108.
Ed. Donath 《Fresenius' Journal of Analytical Chemistry》1901,40(3):137-141
Ohne Zusammenfassung 相似文献
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Ed. Donath 《Fresenius' Journal of Analytical Chemistry》1901,40(3):141-143
Ohne Zusammenfassung 相似文献