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11.
Wolfgang Stadlbauer Herbert Lutschounig Gerda Schindler Theo Witoszynskyj Thomas Kappe 《Journal of heterocyclic chemistry》1992,29(6):1535-1540
Nitration of 3-substituted-4-hydroxy-2(1H)-quinolones 1 with nitric acid leads either to 3-nitro- 2 or 3-hydroxyquinolinediones 3 , depending on the reaction conditions. 3-Substituted-3-hydroxyquinolinediones 3 are also obtained by oxidative hydroxylation with peracetic acid. Amination of 3-substituted-3-chloroquinolinediones 4 with ammonium hydroxide predominantly leads again to 3-substituted-3-hydroxyquinolinediones 3 , only in one case the 3-aminoquinolinedione 5 could be isolated. With morpholine or pyridine as amines the expected 3-aminoquinolinediones 6 and 7 were obtained. 相似文献
12.
Nicole Frankenberg Christine Hager-Braun Ute Feiler Markus Fuhrmann Hans Rogl Nikolaus Schneebauer Nathan Nelson Günter Hauska 《Photochemistry and photobiology》1996,64(1):14-19
Membranes of Chlorobium tepidum contain about 35, 45 and2–10 molecules of menaquinone-7, chlorobium quinone (1′-oxo-menaquinone-7) and of the polar menaquinone (probably 1′-OH-menaquinone-7) per reaction center, respectively. None of these quinones was retained during the isolation of P840-reaction centers beyond the detection limit of about 0.2 quinones per reaction center, neither in the core complex nor in functionally intact reaction center preparations. The latter is shown to catalyze the formation of an electrochemical proton gradient in the presence of ascorbate and phenazinium methosulfate, when it is incorporated into lipid vesicles. 相似文献
13.
Gerda Rogl Viktor Soprunyuk Wilfried Schranz Michael J. Zehetbauer Jiri Bursik Herbert Müller Ernst Bauer Peter F. Rogl 《无机化学与普通化学杂志》2020,646(14):1267-1272
Thermoelectric materials with a high figure of merit, ZT, are the essential basis to build thermoelectric generators, which can directly convert heat into electricity. Severe plastic deformation (SPD) via high-pressure torsion (HPT) was successfully applied to enhance ZT of ball-milled and hot-pressed skutterudites as well as to produce bulk nanostructured skutterudites directly from powders. SPD introduces many defects into the sample and in parallel the crystallite size is significantly reduced. During measurement-induced heating these defects anneal partially out, and the grains grow. In this work for the first time systematically the changes of the temperature-dependent electrical resistivity and of thermal expansion were compared. It could be shown that for p- and n-type skutterudites, being hot-pressed and HPT-processed as well as directly HPT-processed from compacted powder, these changes occur more or less simultaneously within the same temperature ranges. This evaluation gives a much deeper insight into the thermoelectric behavior of HPT samples under the influence of changing temperature. 相似文献
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Magnetic properties and structural chemistry of ternary silicides (RE,Th, U)Ru2Si2 (RE = RARE EARTH)
K. Hiebl C. Horvath P. Rogl M.J. Sienko 《Journal of magnetism and magnetic materials》1983,37(3):287-296
Ternary silicides (RE, Th, U)Ru2Si2 have been synthesized from the elements. All the compounds (RE = Y, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) were found to be isotypic and to crystallize with the structure type of ThCr2Si2 (ordered derivative of the BaAl4-type). The magnetic behavior of these alloys was studied in the temperature range 1.5 K < T < 1100 K. Magnetic susceptibilities at temperatures T > 300 K closely follow a typical Van Vleck paramagnetism of free RE3+-ions. In the case of CeRu2Si2 susceptibilities are well described for 20 K < T < 1100 K by a Van Vleck paramagnetism of widely spaced multiplets; the observed effective paramagnetic moment μeff = 2.12 BM indicates a high percentage (85%) of Ce3+. SmRu2Si2 yields an effective moment μeff = 0.54 BM, which compares reasonably well with the Hund's rule J = 5/2 ground level for free Sm+ and a low-lying excited level with J = 7/2. For temperatures T > 15 K the magnetic susceptibility as a function of temperature follows the “Van Vleck behavior” for free Sm3+. At low temperatures ferromagnetic ordering was encountered for (Pr, Nd, Ho, Er, Tm)Ru2Si2, whereas antiferromagnetic ordering was observed for (Sm, Gd, Tb, Dy)Ru2Si2. The ordering temperatures are generally below 55 K. No superconductivity was found for temperatures as low as 1.8 K. 相似文献
17.
New -oxides: {Zr, Hf}9Os4O3 and new -oxides: {Ti, Zr, Hf}3Zn3O
x
and Hf4Os2O0.75 were prepared.Considering the different modes of filling the voids, a new classification of the variety of -phases is presented.
Mit 2 Abbildungen 相似文献
Mit 2 Abbildungen 相似文献
18.
Renk KF Stahl BI Rogl A Janzen T Pavel'ev DG Koshurinov YI Ustinov V Zhukov A 《Physical review letters》2005,95(12):126801
We report a superlattice parametric oscillator (SPO), with a GaAs/AlAs superlattice as the active element. The SPO was pumped by a microwave field (power 4 mW) and produced third harmonic radiation at subterahertz frequencies (near 300 GHz; 0.1 mW). We attribute the parametric gain to the nonlinearity of the miniband transport. 相似文献
19.
Yogi M Kitaoka Y Hashimoto S Yasuda T Settai R Matsuda TD Haga Y Onuki Y Rogl P Bauer E 《Physical review letters》2004,93(2):027003
We report on novel antiferromagnetic (AFM) and superconducting (SC) properties of noncentrosymmetric CePt3Si through measurements of the 195Pt nuclear spin-lattice relaxation rate 1/T(1). In the normal state, the temperature (T) dependence of 1/T(1) unraveled the existence of low-lying levels in crystal-electric-field multiplets and the formation of a heavy-fermion (HF) state. The coexistence of AFM and SC phases that emerge at T(N)=2.2 K and T(c)=0.75 K, respectively, takes place on a microscopic level. CePt3Si is the first HF superconductor that reveals a peak in 1/T(1) just below T(c) and, additionally, does not follow the T3 law that used to be reported for most unconventional HF superconductors. We remark that this unexpected SC characteristic may be related to the lack of an inversion center in its crystal structure. 相似文献
20.
Werner Paschinger Kunio Yubuta Yuta Saiga Toshiro Takabatake Gerald Giester Peter Rogl 《ChemInform》2016,47(29):no-no
Single crystals of Ce3Pt4Sn6 (I) and Ce1‐xPt6Al13+2x (x = 0.207, (II)) are isolated by mechanical fragmentation of specimens grown from self‐fluxes (Sn or Al, resp.) by slow cooling from the melt. 相似文献