ChemInform Abstract: A New Type of Angular Phenothiazine Ring System.

1986 ◽  
Vol 17 (38) ◽  
Author(s):  
C. O. OKAFOR
Keyword(s):  
Ring System ◽  
New Type

ChemInform Abstract: THE BIS(TETRATHIOTUNGSTATO)DIAURATE(2-) ANION, A NEW TYPE OF INORGANIC RING SYSTEM

1978 ◽  
Vol 9 (13) ◽  
Author(s):  
A. MUELLER ◽  
H. DORNFELD ◽  
G. HENKEL ◽  
B. KREBS ◽  
M. P. A. VIEGERS
Keyword(s):  
Ring System ◽  
New Type

A new type of angular phenothiazine ring system

Tetrahedron ◽  
1986 ◽  
Vol 42 (10) ◽  
pp. 2771-2775 ◽  
Author(s):  
Charles O. Okafor
Keyword(s):  
Ring System ◽  
New Type

scholarly journals Synthesis of a New Type of Trans-Decalin Vitamin D Analogue through a Dyotropic Ring Expansion

2021 ◽  
Vol 2021 ◽  
pp. 1-5
Author(s):  
Hugo Santalla ◽  
Uxía Gómez-Bouzó ◽  
Irene Sánchez-Sanz ◽  
Yagamare Fall
Keyword(s):  
Vitamin D ◽  
Research Group ◽  
Ring Expansion ◽  
Ring System ◽  
Side Chain ◽  
Sulphur Atom ◽  
Mild Conditions ◽  
New Type ◽  
Vitamin D Analogue

A new vitamin D analogue with a trans-fused decalin as the CD-ring system and containing a sulphur atom in the side chain has been synthesized in our research group. The obtention of this analogue is based on a recently discovered transformation of hydrindane cores into decalins through a dyotropic ring expansion in very mild conditions.

Synthesis of substituted octahydroindolo[2,3-a]-quinolizines. The formation of a new type of ring system

1967 ◽  
Vol 32 (2) ◽  
pp. 423-427 ◽  
Author(s):  
Csaba Szantay ◽  
Laszlo Toke ◽  
Katalin Honty ◽  
Gyorgy Kalaus
Keyword(s):  
Ring System ◽  
New Type

Pschorr Reactions with Sulphonamides derived from N-Benzyl-o-phenylenediamine: A New Route to Phenanthridine, and a New Type of Molecular Rearrangement

1963 ◽  
Vol 16 (3) ◽  
pp. 417 ◽  
Author(s):  
JL Huppatz ◽  
WHF Sasse
Keyword(s):  
Acetic Acid ◽  
Sulphuric Acid ◽  
Sodium Nitrite ◽  
Ring System ◽  
Sulphonic Acid ◽  
Diazonium Salts ◽  
Molecular Rearrangement ◽  
New Type ◽  
Cuprous Ions

The preparation in three steps of N-benzyl-N-benzenesulphonyl-o-phenylenediamine (Va), of N-benzyl-N-p-toluenesulphonyl-o-phenylenediamine (Vb), and of N-benzyl-N-methanesulphonyl-o-phenylenediamine (Vc) from o-nitroaniline is described. The copper-catalysed decomposition of diazonium salts of each of these amines in acetic acid-sulphuric acid has been examined. Compound (Va) gave N-benzyl-2-aminobiphenyl (IXa), 5-benzenesulphonyl-5,6-dihydrophenanthridine (VIa), N- benzyl-2-aminobiphenyl-2'-sulphonic acid sultam (Xa), N-benzenesulphonyl-2-amino-biphenyl (XIIa), and phenanthridine. Compound (Vb) gave N-benzyl-2-amino-4'-methylbiphenyl (IXb), 6-p-toluenesulphonyl-5,6-dihydrophenanth (VIb), a compound C20H17NO2S thought to be N-benzyl-2-amino-5'-methylbiphenyl-2'-sulphonic acid sultam (Xb), N-benzyl-N-p-toluenesulphonylaniline (XIb), N-p- toluenesulphonyl-2-aminobiphenyl (XIIb), and phenanthridine. Compound (Vc) gave 5-methanesulphonyl-5,6-dihydrophenanthri (VIc), N-benzyl-N-methanesulphonylaniline (XIc), N-methanesulphonyl-2-aminobiphenyl (XIIc), and phenanthridine. It has been found that the yields of most of these products depend inter alia on the excess of sodium nitrite present during the diazotization prior to cyclization. It is suggested that this effect is caused by changes in the concentration of cuprous ions present during the cyclization. Heterolytic and homolytic processes may be involved in the formation of the dihydrophenanthridines and sultams. The formation of the biphenyl derivatives (IX) and (XII) is postulated to proceed via the spirane intermediates (XIX) or (XX).�The conversion of the sulphonamides of dihydrophenanthridine (VI) to phenanthridine in c. 70% yield completes new syntheses of this ring system.

Stochasting modeling of planetary ring systems

1984 ◽  
Vol 75 ◽  
pp. 461-469 ◽  
Author(s):  
Robert W. Hart
Keyword(s):  
Maximum Entropy ◽  
Ring System ◽  
The Sun ◽  
Ultimate State ◽  
Interparticle Interactions ◽  
Ring Systems ◽  
First Order ◽  
Planetary Ring ◽  
Insight Into

ABSTRACTThis paper models maximum entropy configurations of idealized gravitational ring systems. Such configurations are of interest because systems generally evolve toward an ultimate state of maximum randomness. For simplicity, attention is confined to ultimate states for which interparticle interactions are no longer of first order importance. The planets, in their orbits about the sun, are one example of such a ring system. The extent to which the present approximation yields insight into ring systems such as Saturn's is explored briefly.

The Microstructure of Shock-Synthesized Diamond

1967 ◽  
Vol 25 ◽  
pp. 324-325
Author(s):  
Lucien F. Trueb
Keyword(s):  
Single Crystals ◽  
Preferred Orientation ◽  
High Magnification ◽  
Texture Pattern ◽  
Shock Process ◽  
New Type ◽  
Diffraction Diagram

A new type of synthetic industrial diamond formed by an explosive shock process has been recently developed by the Du Pont Company. This material consists of a mixture of two basically different forms, as shown in Figure 1: relatively flat and compact aggregates of acicular crystallites, and single crystals in the form of irregular polyhedra with straight edges.Figure 2 is a high magnification micrograph typical for the fibrous aggregates; it shows that they are composed of bundles of crystallites 0.05-0.3 μ long and 0.02 μ. wide. The selected area diffraction diagram (insert in Figure 2) consists of a weak polycrystalline ring pattern and a strong texture pattern with arc reflections. The latter results from crystals having preferred orientation, which shows that in a given particle most fibrils have a similar orientation.

New type electron gun with electrostatic and electromagnetic lenses

1978 ◽  
Vol 36 (1) ◽  
pp. 62-63
Author(s):  
T. Ichinokawa ◽  
H. Maeda
Keyword(s):  
Electron Microscopy ◽  
Electron Beam ◽  
Optimum Condition ◽  
Bias Voltage ◽  
Electron Gun ◽  
Charge Effect ◽  
Micro Fabrication ◽  
Maximum Brightness ◽  
New Type ◽  
The Ideal

I. IntroductionThermionic electron gun with the Wehnelt grid is popularly used in the electron microscopy and electron beam micro-fabrication. It is well known that this gun could get the ideal brightness caluculated from the Lengumier and Richardson equations under the optimum condition. However, the design and ajustment to the optimum condition is not so easy. The gun has following properties with respect to the Wehnelt bias; (1) The maximum brightness is got only in the optimum bias. (2) In the larger bias than the optimum, the brightness decreases with increasing the bias voltage on account of the space charge effect. (3) In the smaller bias than the optimum, the brightness decreases with bias voltage on account of spreading of the cross over spot due to the aberrations of the electrostatic immersion lens.In the present experiment, a new type electron gun with the electrostatic and electromagnetic lens is designed, and its properties are examined experimentally.

A new type of defect structure in 124-superconducting oxide revealed by HREM

1991 ◽  
Vol 49 ◽  
pp. 1092-1093
Author(s):  
R. Sharma ◽  
B.L. Ramakrishna ◽  
N.N. Thadhani ◽  
D. Hianes ◽  
Z. Iqbal
Keyword(s):  
Shock Wave ◽  
Defect Structure ◽  
Neutron Radiation ◽  
Weak Links ◽  
Defect Structures ◽  
New Materials ◽  
New Type ◽  
Current Densities ◽  
Processing Techniques ◽  
Microstructural Studies

After materials with superconducting temperatures higher than liquid nitrogen have been prepared, more emphasis has been on increasing the current densities (Jc) of high Tc superconductors than finding new materials with higher transition temperatures. Different processing techniques i.e thin films, shock wave processing, neutron radiation etc. have been applied in order to increase Jc. Microstructural studies of compounds thus prepared have shown either a decrease in gram boundaries that act as weak-links or increase in defect structure that act as flux-pinning centers. We have studied shock wave synthesized Tl-Ba-Cu-O and shock wave processed Y-123 superconductors with somewhat different properties compared to those prepared by solid-state reaction. Here we report the defect structures observed in the shock-processed Y-124 superconductors.

ESEM - A multipurpose surface Electron Microscope

1986 ◽  
Vol 44 ◽  
pp. 632-633 ◽  
Author(s):  
G.D. Danilatos
Keyword(s):  
Electron Microscope ◽  
Room Temperature ◽  
Environmental Scanning ◽  
Gas Composition ◽  
Saturated Water Vapor ◽  
Surface Electron ◽  
Current State ◽  
Saturated Water ◽  
New Type ◽  
Temperature And Pressure

Over recent years a new type of electron microscope - the environmental scanning electron microscope (ESEM) - has been developed for the examination of specimen surfaces in the presence of gases. A detailed series of reports on the system has appeared elsewhere. A review summary of the current state and potential of the system is presented here.The gas composition, temperature and pressure can be varied in the specimen chamber of the ESEM. With air, the pressure can be up to one atmosphere (about 1000 mbar). Environments with fully saturated water vapor only at room temperature (20-30 mbar) can be easily maintained whilst liquid water or other solutions, together with uncoated specimens, can be imaged routinely during various applications.

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