Eine Neuberechnung der Atomgewichte

Ohne Zusammenfassung     

Zur Aufschliessung des Chromeisensteines

Ohne Zusammenfassung     

Sinterability studies on K0.5Na0.5NbO3 using laser as energy source

The sinterability of K_0.5Na_0.5NbO₃ (KNN) ceramics by a laser beam has been investigated in the present research. A 100 W CO₂ laser with a beam diameter of 0.6 mm has been used to sinter the KNN specimens prepared on a uniaxial pressing machine. The relations between laser power and thickness of densified layer, crystallographic structures and phase compositions have been studied. A comparison has been made between laser and furnace sintered KNN samples according to the SEM, XRD and XRF results. The possibility of KNN used for the layer-wise laser direct sintering 3D components has been confirmed in this paper.     

Tempern von Cd0,2Hg0,8Te im Quecksilberdampf

N-type Cd_0,2Hg_0,8Te with a minimum concentration and a maximum mobility of charge carriers serves as starting material for the production of photoconductive infrared detectors with high sensitivity. The number of the defects, originating in Cd_0,2Hg_0,8Te during crystal growth, can be considerably diminished by a heat treatment in saturated mercury vapour. Details of the preparation and the accomplishment of the annealing essays as well as the results of the experiments are described.     

Maxima for the Expectation of the Lifetime of a Brownian Motion in the Ball

Let G _B (x, y) be the Green’s function of the unit ball B in ${\mathbb{R}^n, n \ge 3,}$ and ${\Gamma_B (x,y)=\int_BG_B(x, z)G_B(z, y)dz}$ the iterated Green’s function. The function $$E_x^y(\tau_B) = \frac{\Gamma_B(x, y)}{G_B(x, y)}$$ is the expectation of the lifetime of a Brownian motion starting at ${x \in \overline{B}}$ , killed on exiting B and conditioned to converge to and to be stopped at ${y \in \overline{B}}$ . The aim of the paper is to prove that $$\sup_{x \in \partial B,y \in B} E_x^y(\tau_B) = \sup_{x,y \in \partial B} E_x^y(\tau_B) = E_{x_0}^{-x_0}(\tau_B), x_0 \in\partial B$$ and that the maximum value of ${E_x^y(\tau_B)}$ occurs if and only if x, y are diametrically opposite points on the boundary of B.     

Mixed Stekloff Eigenvalue Problem and New Extremal Properties of the Grötzsch Ring

We study the mixed Stekloff eigenvalue problem in doubly connected domains. Using circular symmetrization and a distortion theorem for conformal mappings of an annulus, we find lower bounds for the first eigenvalue. These bounds are sharp for the Grötzsch ring. We also solve an extremal problem for some polygonal doubly connected domains and prove some results concerning the existence of a closed nodal line. Bibliography: 19 titles.     

A Diketopyrrolopyrrole-Based Dimer as a Blue Pigment

1,4-Diketopyrrolo[3,4-c]pyrroles (DPPs) constitute a class of hydrogen-bonded pigments covering a color range from yellow–orange to dark violet. We report facile dimerization of a Boc-substituted 3,6-dithienyl-DPP. The formed dimer shows brilliantly blue color as a result of the expansion of the chromophore. The soluble dimer acts as latent pigment and is converted to the corresponding pigment either via thermocleavage or acidic deprotection of the Boc groups. The synthesized pigment is characterized by high migrational stability in a polymer matrix and a clear blue color.