Effects of rare earth element La on the microstructure of Cumatrix diamond tools were researched under the conditions of variousmaterials components and the process parameters in order to improvematerials properties. ...Effects of rare earth element La on the microstructure of Cumatrix diamond tools were researched under the conditions of variousmaterials components and the process parameters in order to improvematerials properties. SEM, XPS and X-ray were used to investigate thefracture section, microstructure and the element valence inmaterials. The Results shown that the combination of rare earthelement La and transition element Ti is advantageous to the bondingstate Between diamond particles and matrix, so it can improve thematerials properties. Suitable sintering temperature is 790 deg. C.展开更多
The title compound has synthesized and its crystal structure was determined by X-ray analysis. The crystal belongs to monoclinic, space group C2/c with a = 10.413(3), b = 16.080(5), c = 19.188(6) ? b = 94.023(7), V = ...The title compound has synthesized and its crystal structure was determined by X-ray analysis. The crystal belongs to monoclinic, space group C2/c with a = 10.413(3), b = 16.080(5), c = 19.188(6) ? b = 94.023(7), V = 3205(2) 3, Z = 8, Dc =1.440 g/cm3, F(000) = 1424, m(MoKa) = 0.238 mm-1, S = 0.896, R = 0.0454 and wR = 0.0998 for 1914 observed reflections with I ≥ 2s(I). In the title compound (C18H12F3NOS), the side-chain carbonyl group, the adjacent double bond and the amine N from 2-naphthylamine are essentially coplanar with the largest deviation from this plane being 0.018(2) ?for atom C(3). The dihedral angle between the mean plane and the thienyl ring is 4.24(3)? A strong intramolecular NH…O hydrogen bond (N…O 2.666(3) ?and NH…O 142(3)) was observed, which leads to an enamine tautomer in the crystal.展开更多
Google’s algorithm on PageRank is analyzed in details. Some disadvantages of this algorithm is presented, for instance, preferring old pages, ignoring special sites and inaccurate judge of hyperlinks pointed out from...Google’s algorithm on PageRank is analyzed in details. Some disadvantages of this algorithm is presented, for instance, preferring old pages, ignoring special sites and inaccurate judge of hyperlinks pointed out from one page. Furthermore, author’s improved algorithm is described. Experiments show that the author’s consideration on evaluating the importance of pages can make an improvement over the original algorithm. Based on this improved algorithm a topic specific searching system have been developed.展开更多
文摘Effects of rare earth element La on the microstructure of Cumatrix diamond tools were researched under the conditions of variousmaterials components and the process parameters in order to improvematerials properties. SEM, XPS and X-ray were used to investigate thefracture section, microstructure and the element valence inmaterials. The Results shown that the combination of rare earthelement La and transition element Ti is advantageous to the bondingstate Between diamond particles and matrix, so it can improve thematerials properties. Suitable sintering temperature is 790 deg. C.
基金This work was supported by the foundation of Tianjin Scientific Committee (003601711)
文摘The title compound has synthesized and its crystal structure was determined by X-ray analysis. The crystal belongs to monoclinic, space group C2/c with a = 10.413(3), b = 16.080(5), c = 19.188(6) ? b = 94.023(7), V = 3205(2) 3, Z = 8, Dc =1.440 g/cm3, F(000) = 1424, m(MoKa) = 0.238 mm-1, S = 0.896, R = 0.0454 and wR = 0.0998 for 1914 observed reflections with I ≥ 2s(I). In the title compound (C18H12F3NOS), the side-chain carbonyl group, the adjacent double bond and the amine N from 2-naphthylamine are essentially coplanar with the largest deviation from this plane being 0.018(2) ?for atom C(3). The dihedral angle between the mean plane and the thienyl ring is 4.24(3)? A strong intramolecular NH…O hydrogen bond (N…O 2.666(3) ?and NH…O 142(3)) was observed, which leads to an enamine tautomer in the crystal.
文摘Google’s algorithm on PageRank is analyzed in details. Some disadvantages of this algorithm is presented, for instance, preferring old pages, ignoring special sites and inaccurate judge of hyperlinks pointed out from one page. Furthermore, author’s improved algorithm is described. Experiments show that the author’s consideration on evaluating the importance of pages can make an improvement over the original algorithm. Based on this improved algorithm a topic specific searching system have been developed.
