Waveform stability of a traveling high-field domain in a Gunn diode

We assume that a constant voltage is applied across a sample of a Gunn diode of finite length. When a periodic boundary condition is assumed, the dynamical behavior of the electric field within the sample is described by a nonlinear integral-partial differential equation. By using this equation, we can study the waveform stability of a traveling high-field domain of solitary-wave type which plays an essential role in the Gunn effect. We obtain simple criteria which the sample length and the applied voltage must satisfy for the existence and stability of the high-field domain. The stability analysis is carried out by using Liapunov's second method.     

A structure analysis of Ag-adsorbed Si(111) surface by LEED/CMTA

The Ag induced superstructures on the Si(111) surface have been studied by low energy electron diffraction constant momentum transfer averaging (LEED/CMTA) technique. The vertical displacements of the atoms are determined from the analysis of the specularly reflected (00) beam intensities. Unexpected behavior of the Ag atoms is clarified: For the √3 × √3-Ag surface it is verified that the Ag atoms are embedded in the first double layer of Si, leading to a considerable rearrangement of the substrate. In contrast, for the 3 × 1-Ag surface, the Ag atoms are riding on the Si surface and the reconstruction of the substrate is small.     

LEED-AES study of the AuSi(100) system

The system Au/Si(100) has been studied using LEED and AES. Au films grow as Au(111) | Si(100) having six azimuthally rotated orientations at low deposition temperatures below 50°C after the formation of intermediate gold suicide layers. Crystalline gold silicide thin layers are formed on the Au(111) film after heat treatment at 100–400°C. Two types of suicide LEED pattern observed seem to have no correlation with crystallographic data reported on quenched alloy films. Heat treatment over 450°C leads to agglomeration of the film, producing a series of Au-induced superstructures. Heat treatment of the Au film over 1000°C regenerates the clean Si surface accompanied with many etch pits.     

Electron-transfer polymers. XXVIII. Synthesis of vinyl hydroquinone derivatives by means of the wittig reaction

The Wittig reaction has been applied to unsubstituted, monomethyl-, 3,6-dimethyl-, and trimethyl-2,5-dimethoxybenzyl chlorides to produce in quantitative to good yields the corresponding vinyl monomers, unsubstituted, monomethyl-, 3,6-dimethyl-, and trimethyl-2,5-dimethoxystyrenes. The reaction is applicable also to 2,5-dimethoxy-4-methylbenzaldehyde, and to O,O′-bis-(methoxymethyl)resorcinol-4-aldehyde to yield the corresponding vinyl monomers. The reaction is particularly suitable with all these compounds because it is run at room temperature or below and gives good to quantitative yields.     

Bestimmung von Phosphor als Chinolinphosphormolybdat

Zusammenfassung Eine einfache Methode wurde ausgearbeitet, bei der Phosphor als Chinolinphosphormolybdat bestimmt wird. Die Methode ist besonders bei niedrigen Phosphorgehalten und in Gegenwart von fünfwertigem Vanadium zu empfehlen. Eine Reihe von Arbeitsbereichen, in denen die Methode Anwendung findet, wird angegeben.