scholarly journals Chiral Triphenylacetic Acid Esters: Residual Stereoisomerism and Solid-State Variability of Molecular Architectures

2021 ◽  
Author(s):  
Natalia Prusinowska ◽  
Agnieszka Czapik ◽  
Marcin Kwit
Keyword(s):  
Solid State ◽  
Molecular Architectures ◽  
Triphenylacetic Acid ◽  
Acid Esters

N-Methylcarbamoylphosphate, II. Thermische Zersetzung/ N-Methylcarbamoyl Phosphates, II. Thermal Decomposition

1984 ◽  
Vol 39 (8) ◽  
pp. 1095-1099
Author(s):  
Fritz Seel ◽  
Norbert Klein
Keyword(s):  
Thermal Decomposition ◽  
Solid State ◽  
Phosphoric Acid ◽  
Intermediate Product ◽  
Methyl Isocyanate ◽  
Hydrogen Phosphate ◽  
Aqueous Suspensions ◽  
Protic Solvents ◽  
Acid Esters

AbstractThe thermal decomposition of various salts of mono-N-methylcarbamoyl and bis-N-methylcarbamoyl phosphoric acid in aprotic and protic solvents (acetonitrile, trichlorom ethane, alcohols) and in the solid state has been studied in detail. Final products are mono-, di-, poly-, and cyclophosphates, in addition phosphoric acid esters if alcohols are used as solvents; and either sym. dimethylurea or methyl isocyanate and methylamine. The spontaneous decomposition of sparingly soluble N-methyl carbamoyl phosphates in aqueous suspensions to yield slightly soluble diphosphates demonstrates clearly that the reaction of calcium hydrogen phosphate with alkali cyanates via calcium carbam oylphosphate to give calcium diphosphate - which has been considered a prebiotic key reaction - is not a result of a special feature of the structure of the intermediate product.

Autoxidation of cholesterol fatty acid esters in solid state and aqueous dispersion

Lipids ◽  
1982 ◽  
Vol 17 (10) ◽  
pp. 703-708 ◽  
Author(s):  
V. Korahani ◽  
J. Bascoul ◽  
A. Crastes de Paulet
Keyword(s):  
Fatty Acid ◽  
Solid State ◽  
Aqueous Dispersion ◽  
Fatty Acid Esters ◽  
Acid Esters

Preparation of Thin Cadmium Telluride Samples for Electron Microscope Studies

1974 ◽  
Vol 32 ◽  
pp. 548-549
Author(s):  
T. J. Magee ◽  
J. Peng ◽  
J. Bean
Keyword(s):  
Electron Microscope ◽  
Sulfuric Acid ◽  
Solid State ◽  
Sample Preparation ◽  
Cadmium Telluride ◽  
Potassium Dichromate ◽  
Optical Components ◽  
The Past ◽  
Solid State Devices

Cadmium telluride has become increasingly important in a number of technological applications, particularly in the area of laser-optical components and solid state devices, Microstructural characterizations of the material have in the past been somewhat limited because of the lack of suitable sample preparation and thinning techniques. Utilizing a modified jet thinning apparatus and a potassium dichromate-sulfuric acid thinning solution, a procedure has now been developed for obtaining thin contamination-free samples for TEM examination.

The Collagenic Molecular Structural Unit of Solid State Complexes

1971 ◽  
Vol 29 ◽  
pp. 478-479
Author(s):  
Kenneth M. Richter ◽  
John A. Schilling
Keyword(s):  
Molecular Weight ◽  
Solid State ◽  
Structural Unit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Naoh Treatment

The structural unit of solid state collagen complexes has been reported by Porter and Vanamee via EM and by Cowan, North and Randall via x-ray diffraction to be an ellipsoidal unit of 210-270 A. length by 50-100 A. diameter. It subsequently was independently demonstrated by us in dog tendon, dermis, and induced complexes. Its detailed morphologic, dimensional and molecular weight (MW) aspects have now been determined. It is pear-shaped in long profile with m diameters of 57 and 108 A. and m length of 263 A. (Fig. 1, tendon, KMnO4 fixation, Na-tungstate; Fig. 2a, schematic of unit in long, C, and x-sectional profiles of its thin, xB, and bulbous, xA portions; Fig. 2b, tendon essentially unmodified by ether and 0.4 N NaOH treatment, Na-tungstate). The unit consists of a uniquely coild cable, c, of ṁ 22.9 A. diameter and length of 2580-3316 A. The cable consists of three 2nd-strands, s, each of m 10.6 A.

Structure-property relations of liquid crystalline polymers

1987 ◽  
Vol 45 ◽  
pp. 460-463
Author(s):  
Linda C. Sawyer
Keyword(s):  
Solid State ◽  
Liquid Crystalline ◽  
Structural Model ◽  
Crystalline Polymer ◽  
Liquid Crystalline Polymers ◽  
Mechanical Anisotropy ◽  
Structure Property ◽  
Preparation Methods ◽  
Crystalline Polymers ◽  
Extended Chain

Recent liquid crystalline polymer (LCP) research has sought to define structure-property relationships of these complex new materials. The two major types of LCPs, thermotropic and lyotropic LCPs, both exhibit effects of process history on the microstructure frozen into the solid state. The high mechanical anisotropy of the molecules favors formation of complex structures. Microscopy has been used to develop an understanding of these microstructures and to describe them in a fundamental structural model. Preparation methods used include microtomy, etching, fracture and sonication for study by optical and electron microscopy techniques, which have been described for polymers. The model accounts for the macrostructures and microstructures observed in highly oriented fibers and films.Rod-like liquid crystalline polymers produce oriented materials because they have extended chain structures in the solid state. These polymers have found application as high modulus fibers and films with unique properties due to the formation of ordered solutions (lyotropic) or melts (thermotropic) which transform easily into highly oriented, extended chain structures in the solid state.

Microstructural Variations in Melt-Spun Rapidly Solidified Ribbons

1985 ◽  
Vol 43 ◽  
pp. 54-55
Author(s):  
L. A. Bendersky ◽  
W. J. Boettinger
Keyword(s):  
Solid State ◽  
Processing Parameters ◽  
Heat Extraction ◽  
Solid State Reactions ◽  
Careful Examination ◽  
Ion Milling ◽  
Melt Spun ◽  
Wheel Side ◽  
Rapidly Solidified ◽  
Heat Extraction Rate

Rapid solidification produces a wide variety of sub-micron scale microstructure. Generally, the microstructure depends on the imposed melt undercooling and heat extraction rate. The microstructure can vary strongly not only due to processing parameters changes but also during the process itself, as a result of recalescence. Hence, careful examination of different locations in rapidly solidified products should be performed. Additionally, post-solidification solid-state reactions can alter the microstructure.The objective of the present work is to demonstrate the strong microstructural changes in different regions of melt-spun ribbon for three different alloys. The locations of the analyzed structures were near the wheel side (W) and near the center (C) of the ribbons. The TEM specimens were prepared by selective electropolishing or ion milling.

Si(Li) detector for microanalysis cooled by thermoelectric device

1992 ◽  
Vol 50 (2) ◽  
pp. 1736-1737
Author(s):  
Shaul Barkan
Keyword(s):  
Solid State ◽  
Liquid Nitrogen ◽  
Thermoelectric Device ◽  
Peltier Cooler ◽  
Complicated Process ◽  
The Common

Cooling down solid state detecors, with other different way then liquid Nitrogen, is a goal of many vendors and customers since the invention of these detectors. THe disadvantage of the common way of liquid Nitrogen is first the inavailibility of the LN in many uses (like space military and any other applications that are not done inside a well organize Laboratory). The use of LN also considers as a Labor consumer in addition to the big dewar that has to be added to any detector for storing the LN, the boiling of the LN, may cause microphonics problesm and the refiling of the dewar in many Labs is a complicated process due to inconvenience location of the microscope.In this paper I will show a spectra result of 10mm2 SiLi detector for microanalysis use, cooled by peltier cooler. The peltier cooler has the advantage of non-microphonics and non-labor needed (like adding LN to the dewar).

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