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61.
62.
W18Cr4V 总被引:2,自引:1,他引:1
The frictionand
wear characteristics of the surfa ce compound layer of W18Cr4V steel by combined treatment
of ion nitrocarburizing-ion sulphurizing were investigated. The friction coefficient of
the compound l ayer against GCr15 steel was determined witha block-ring friction tester.
The wear test was carried out with a reciprocating wear tester. The worn surface was
analyzedby scanning electron microscopy(SEM). The experimental results reveale d that the
friction coefficient was lower for treatedW18Cr4V steel against GCr1 5 steel. The wear
resistance of the compound layer was higher because the nitroc arbonide andthe sulphide in
the compound layer were capable of friction-reduct ion and adhesion-inhibition. 相似文献
63.
Xuexi Tie a Junji Cao b a National Center for Atmospheric Research Boulder CO USA b SKLLQG Institute of Earth Environment Chinese Academy of Sciences No. Fenghui South Road High-Tech Zone Xi’an China 《中国颗粒学报》2010,8(1)
PARTICUOLOGY regrets that the above paper was mistakenly classified as a ‘Review’ rather than an ‘Invited paper’ when originally published in volume 7, issue 6, 426–431. 相似文献
64.
LI Hao-Honga CHEN Zhi-Ronga② REN Yong-Gang LI Jun-Qiana b HUANG Chang-Canga ZHAO Bina a 《结构化学》2005,(12)
1 INTRODUCTION terested in the unique effects associated with substituents at 4- and 7-positions of the phenan- The coordination chemistry of 1,l0-phenanthroline throline ring. Thus, when phenyl groups are present, and its derivatives has captured the attention of che- the absorptivities of the CT transitions are increased mists for years. The reports on biological importance[1~4], markedly due to the extension of the dipole moment supramolecular chemistry[5], electronic spectra[6], conne… 相似文献
65.
Dráb T Kračmerová J Tichá I Hanzlíková E Tichá M Liberda J 《Journal of separation science》2011,34(14):1692-1695
Native polyacrylamide electrophoresis in the presence of two reversible protein anionic stains (Ponceau S and Ponceau 2R) was used to study the oligomeric states of soluble proteins. A mild binding of the used protein stains to nondissociated protein oligomers imposed a charge shift on the proteins resulting into separation of protein species according to their size under physiological conditions. Adsorbed stains could be easily removed after electrophoresis by washing of polyacrylamide gel with buffer and protein complexes could be visualized either by the detection of their enzyme activity or by using a nonspecific protein stain. The specific detection of enzyme activity of glycosidases, lactate dehydrogenase, or phosphatases was shown as an example. 相似文献
66.
Hai-xia Yang Jin-gang Liu Xiao-juan Zhao Yan-feng Li Lin Fan Shi-yong Yang a School of Chemistry Chemical Engineering Lanzhou University Lanzhou China b Laboratory of Advanced Polymer Materials Institute of Chemistry Chinese Academy of Sciences Beijing China 《高分子科学》2005,(5)
A new type of aromatic tetraamine containing biphenyl moiety in the side chain was synthesized via a modified Chichibabin's reaction.3-Nitro-4-acetamidoacetophenone was reacted with 4-phenyl benzaldehyde in the presence of ammonium acetate to obtain 2,6-bis(3',4'-diaminophenyl)-4-biphenyl pyridine(DPPA).A series of polypyrrolones(PPys) were prepared using tetraamine and various aromatic dianhydrides via a two-step cyclization procedure.All the PPys show excellent high temperature stabilities with the initial decomposition temperatures of 530-549℃ and residual weight ratio of 49%-80% at 750℃ in nitrogen.The polymers exhibit no apparent glass transition temperatures(T_gs)except PPy-1 (T_g=327℃),which is derived from tetraamine DPPA and 2,2-bis[4-(3',4'-dicarboxyphenoxy)-phenyl]propane dianhydride (BPADA).In addition,the polymers have acceptable mechanical properties with the tensile strength of 65-94 MPa.The PPy films show excellent hydrolysis-resistance in alkaline aqueous medium and could maintain most of the properties even after boiling in 10% aqueous sodium hydroxide solution for a week. 相似文献
67.
1 INTRODUCTION The 1,4-dihydropyridines (1,4-DHPs) are biologi- cally interesting compounds and have been developed extensively in pharmacology. 1,4-DHP derivatives are used therapeutically in the treatment of cardio- vascular disorders, especially hypertension and coro- nary heart disease such as angina pectoris, atheros- clerosis, etc. The DHPs have emerged as one of the most important classes of drugs for the treatment of gastrointestinal disease, Raynaud?s disease, pulmonary hyper… 相似文献
68.
1 INTRODUCTION Schiff’s bases are well known ligands representedby many bi-, tri-, tetra-, and hexa-dentate example-es[1], but heptadentate ligands are relatively rare[2, . 3]We have reported a copper complex of tetradentateSchiff’s bases[4]… 相似文献
69.
StructureofCytochromecandItsPlatinum┐modifiedDerivativesbyFourierTransformInfraredSpectroscopyJIANGLi-juana,SUNWei-yina,FANGJ... 相似文献
70.
WANG Yong-Jinga b ZHANG Han-Huia b② HUANG Chang-Canga b YU Xiao-Honga SUN Qiao-Zhena SUN Rui-Qinga a 《结构化学》2004,(8)
1 INTRODUCTION As a rich remarkable class of inorganic cluster systems, polyoxometalates continue to be the focus of significant attention in the 21th century because of their various and alluring topologies as well as their unusual physicochemical prope… 相似文献