Grating coatings with gain

Using an integral theory of grating diffraction we calculate efficiencies greater than 100% if a coating with gain is taken into account. A connection with guided modes is conjectured. The application in optical computing seems to be possible.     

Spontaneous photorefractive effect in Sr1−x CaxTiO3 (x=0.014)

The temperature dependence of the principal values of the refractive index in Sr_1−x Ca_xTiO₃ (x=0.014) has been measured in the 17–275 K range under various conditions of sample illumination with 1.96 eV photons. The spontaneous photorefractive contribution δn ^ph to the temperature-induced variation of the refractive index of Sr_1−x Ca_xTiO₃, which appears after illumination of the sample in the ferrophase (transition temperature T _c=32 K) and persists in the paraphase under heating up to 150 K, has been separated. The photoinduced polarization has been estimated. Fiz. Tverd. Tela (St. Petersburg) 39, 711–713 (April 1997)     

Über P–P-haltige cyclische Verbindungen. II

On P? P Containing Cyclic Compounds. II. Reaction of N,N'-dimethylthiourea with phenyl dichlorophosphane yields 1.4-dimethyl-2. 3-diphenyl-1.4.2.3-diazadiphospholidine-5-thione-2-sulfide ( II ). The compound is characterized by its nmr, vibration and mass spectra as well as the results of an X-ray structural analysis. Byproduct of the reaction is N-(N,N'-dimethylcarbamimidoyl)-N,N'-dimethyl thiourea hydrochloride ( III ), which crystallizes with pyridinium chloride. Molecular and crystal structure are reported. With methyl dichlorophosphane N,N'-dimethylthiourea forms 1.2.3.4-tetramethyl-1.4.2.3-diazadiphospholidine-5-thione-2-sulfide ( IV ), which is characterized by its nmr and vibration spectra.     

Diazadiphosphetidine. VIII. Weitere Diazadiphosphetidin-oxide und ein -oxid-sulfid

Diazadiphosphetidines. VIII. Further Diazadiphosphetidine Oxides and an Oxide Sulfide Synthesis and properties of 1,3-dimethyl-2-phenyl-4-diethylamino-1,3,2,4-diazadiphosphetidine-2-oxide ( II ), 1,3-dimethyl-2-diethylamino-4-phenyl-1,3,2,4-diazadiphosphetidine-2-sulfide-4-oxide ( III ), and 1,3-dimethyl-2,4-diphenyl-1,3,2,4-diazadiphosphetidine-2,4-dioxide ( V ) are reported.     

Diazadiphosphetidine. VII. Neue Diazadiphosphetidin-oxide und -oxid-sulfide

Diazadiphosphetidines. VII. New Diazadiphosphetidine Oxides and Oxide Sulfides By reaction of phosphoric tris(methylamide) with tris(dimethylamino)phosphane and tris(diethylamino)phosphane, the diazadiphosphetidine oxides V and I , as well as VI and II are obtained, respectively. With elemental sulfur these compounds form the diazadiphosphetidine oxide sulfides VI and III , as well as VIII and IV , respectively. The n.m.r. spectra of the compounds II — VII are reported and discussed.     

Domain wall relaxation,creep, sliding,and switching in superferromagnetic discontinuous Co(80)Fe(20)/Al(2)O3 multilayers

The ac susceptibility of a superferromagnetic discontinuous multilayer [Co(80)Fe20(1.4 nm)/Al(2)O3(3 nm)](10) is measured as a function of temperature, frequency, and field amplitude and compared to static and dynamic hysteresis loops. Its properties are successfully mapped onto the predicted [T. Nattermann, V. Pokrovsky, and V. M. Vinokur, Phys. Rev. Lett. 87, 197005 (2001)]] dynamical phase transitions, which link the relaxation, creep, sliding, and switching regimes of pinned domain walls.