共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
Within the group of boride and suicide containing hard alloys, those based on copper have recently found increasing interest as wear-resisting stratification and high-temperature structural materials. For the development of the best alloy, the phase conditions in the systems nickel-copper-boron and nickel-copper-silicon were elucidated from the isothermal profiles at 700°. Melting behaviours (important from a practical point of view) in the area of low metalloid contents are presented in the cases of (Ni-Cu-B) mixed crystals, Ni3B alloy, as well as Ni-Cu-10 atomic % B and Ni-Cu-10 atomic % Si. 相似文献
3.
Zusammenfassung 1. Es werden mittels Elektrodialyse und Elektrodekantierung die hochgereinigten azidoiden blauen Farbsole aus Congorot, Congorubin,
Congokorinth G, Benzopurpurin 4 B und Chicagoblau 6 B sowie zum Vergleich das basische Farbsol von Nachtblau hergestellt.
2. Diese Sole werden in bezug auf ihre elektrochemischkonstitutiven sowie Assoziations?nderungen durch Bestimmung ihrer thermischen
Leitf?higkeitsabh?ngigkeit (x, t-Kurve) und deren Reversibilit?t sowie der Verdünnungs?nderung ihrer molekularen Leitf?higkeiten μ untersucht.
3. Es wird gezeigt, wie bei den genannten azidoiden Farbsolen, die s?mtliche Aminosulfos?uren darstellen, die Assoziationskr?fte
mit der inneren Salzbildung wachsen und wie andererseits mit der Zunahme der polaren sauren Gruppen infolge der thermischen
oder Verdünnungsaminolyse des inneren Salzes die Desassoziation erh?ht wird. Das Nachhinken der Leitf?higkeitswerte beim Wiederabkühlen
ist der Ausdruck einer Assoziationshysteresis. Mit der Zeit stellt sich beim Stehen ein Assoziationsgleichgewicht ein.
4. Gegenüber dem Congoblau weisen Congorubin und Congokorinth eine Verminderung um eine NH2-Gruppe, dagegen eine zus?tzliche OH-Gruppe auf, welche je nach ihrer Stellung den sauren Charakter mehr oder weniger verst?rkt.
Die Halbierung der inneren Salzbildung und die Steigerung der Gesamtladung pr?gen sich genau in der zu erwartenden Reihenfolge
steigender molekularer Leitf?higkeit und der Desassoziation aus. Auch das Verhalten des azidoiden Benzopurpurin- und Chicagoblausols
ist hinsichtlich desx, t-Ganges und der μ-Werte sowie der Kolloid?quivalente durchaus das konstitutiv erwartete.
5. Es lassen sich plausible Modelle des Aufbaues der verschiedenen ionischen Micellen bei den einzelnen Farbsolen aufstellen.
6. Die Beziehungen der Farbsole zu den Seifensolen einerseits und den Proteinsolen andererseits werden kurz er?rtert. 相似文献
4.
Synthesis and Structure of Ba2MnO3 Single crystals of Ba2MnO3 could be prepared by solid state reaction in hydrogen atmosphere. X-ray structure investigations gave a monoclinic unit cell (a = 584; b = 1157.9; c = 1270.7 pm; β = 93.74°; space group C? Cc). Mn2+ forms isolated tetrahedron chains connected by 7-fold coordinated Ba2+. 相似文献
5.
Preparation and Crystal Structure of BaLi[BO3] For the first time colourless lamellar single crystals of BaLi[BO3] have been prepared from intimate mixtures of BaO2, Li2O and B2O3. The structure determination from four-circle diffractometer data (MoKα , 882 independent reflections, R = 2.4%, Rw = 1.9%) confirms the space group P 21/c with Z = 4; a = 646.1(3), b = 710.7(2), c = 740.3(3) pm, β = 117.99(3)°. Characteristic units of the structure are layers {Li[BO3]} parallel to (100) consisting of trigonal planar [BO3] groups and distorted [LiO5] pyramids. Effective Coordination Numbers (ECoN), Mean Fictive Ionic Radii (MEFIR), the Madelung Part of Lattice Energy (MAPLE) and the Charge Distribution (CHARDI) are calculated and discussed. 相似文献
6.
7.
8.
9.
10.
K. Bormann 《Fresenius' Journal of Analytical Chemistry》1967,229(6):463-464
Ohne Zusammenfassung 相似文献
11.
The three component reactions comprising the interaction of cyanamide ( 1 ) and s-triazine ( 2 ) with a secondary amine ( 5 ) leads to dehydro-N-Mannich bases ( 6 ). Of this compound class, 6a, b, and c exhibit antimycolic activity. 相似文献
12.
13.
14.
15.
16.
Wool is a fibrous biomaterial with an exceptional multicellular structure and complex chemical composition. This is shown for some selected topics. 相似文献
17.
Synthesis of Trimethylsilyl Substituted Polyhedra of Calcium, Tin(II), and Phosphorus The reaction of calcium-bis[bis(trimethylsilyl)amide] with bis(trimethylsilyl)phosphane in thf yields the heteroleptic, dimeric (tetrahydrofuran-O)calcium-bis(trimethylsilyl)amidebis(trimethylsilyl)phosphanide 1 (triclinic, P 1 , a = 1066,6(2), b = 1141,3(2), c = 1226,6(2)pm, α = 97,78(3)°, β = 107,47(3)°, γ = 101,12(3)°, Z = 1 dimer). The bridging phosphanide-substituent displays with Ca? P bond lengths of 292,6 and 300,5 pm a distortion of the four-membered Ca2P2-cycle. The reaction with another equivalent of HP(SiMe3)2 in thf leads to the formation of tetrakis(tetrahydrofuran-O)calcium-bis[bis(trimethylsilyl)phosphanide] 2 mit Ca? P distances of 292 pm (monoclinic, P21/c, a = 1626,0(3), b = 1295,3(4), c = 2039,5(5) pm, β = 102,60(2)°, Z = 4). The performance of the reaction in the presence of bis[bis(trimethylsilyl)amino]stannylene yields heterobimetallic compounds with a central polyhedron of Ca-, Sn- and P-atoms. Dependent on the Sn/Ca ratio the isolation of tris(trimethylsilyl)phosphane as well as bis[tris(tetrahydrofuran-O)calcium]-ditin(II)-tetrakis(μ3-trimethylsilylphosphandiide) 3 with a central dicalcia-distanna-tetraphosphacubane-fragment or (thf)2CaSn2[μ-P(SiMe3)2]2[μ3-PSiMe3]2 4 (orthorhombic, Pnma, a = 2247,7(2), b = 1868,9(1), c = 1168,0(1) pm, Z = 4), respectively, succeeds. The Ca? P distances lie at 291 pm. 相似文献
18.
Amido Ligands for the Synthesis of Polynuclear Lanthanoid Complexes By 1 : 1 reaction of LnBr3 with NaNHPh in THF the Rare-Earth Complexes [Ln2Br4(μ2-NHPh)2(thf)5] (Ln = Sm ( 1 ), Ln = Gd ( 2 )) with two bridging anilido ligands are obtained. In the system LnBr3/NaNHPh/(Me2SiO)3 the tetranuclear compounds [Ln4(μ4-O)(NHPh)3(OSiMe2NPh)6Na5(thf)7] · THF (Ln = Gd ( 3 ), Ln = Yb ( 4 )) can be built up. They have a central μ4-oxygene atom in the Ln4-tetrahedron. It has an oxa-dimethylsilyl-N-phenylamido ligand over all edges and an anilido ligand on three vertexes. By this reaction small amount of [Na4(thf)6Yb2(OSiMe2NPhSiMe2O)2(OSiMe2NPh)2(NHPh)2] ( 5 ) with a O- and N-bridged Yb–Na polyhedron and N-phenyl-bis(dimethylsilanolato)-ligands coordinating μ2-η2 with its oxygen atoms are obtained. Reaction of Lanthanideshalides with LiNHtBu leads to dimeric complexes. The formation of bridging oxasilylamido ligands is also observed. The compound [Li2Ln(OSiMe2NtBu)2(HNtBu)(thf)]2 (Ln=Sm ( 6 ), Gd ( 7 ) and Yb ( 8 )) contains now an O- and N-bridged Ln–Li polyhedron. (Crystal Data of 1–8 see ‘‘Inhaltsverzeichnis”︁”︁). 相似文献
19.
20.
Ernst Wachtel Peter Terzieff Josef Bahle 《Monatshefte für Chemie / Chemical Monthly》1986,117(12):1349-1366
The phase equilibria on the Mn-rich side of the systems Cu-Mn and Mn-Sn were determined by susceptibility measurements at high temperatures. The phase relationships observed on the Mn-rich side of the system Cu-Mn as well as the susceptibility transformation diagram are in good accordance with the phase diagrams given in the literature. According to our measurements in the system Mn-Sn the -Mn phase field extends to about 10.2 at.% Sn at 1 302 K. The -Mn phase ranging to 7.5 at.% Sn was found to decompose eutectoidally at 1 315 K. The peritectic formation of the hexagonal phase with the approximate composition of Mn3Sn occurs at 1 257 K. The Mn-rich boundary of the two-phase field -Mn+Mn3Sn is located at about 10 at.% Sn.The magnetic susceptibility of liquid Mn-rich Cu-Mn and Mn-Sn alloys follows a modified Curie-law. Above a critical concentration—14 at.% Cu in the system Cu-Mn and 11.2 at.% Sn in the system Mn-Sn—localized magnetic moments due to the Mn atoms are observed.
Herrn Prof. Dr.Kurt L. Komarek anläßlich seines 60. Geburtstages gewidmet. 相似文献