Precursors of Wireless Telegraphy

Synthesis and Characterization of Nanocrystalline Magnetic Pigment via Coordinated Precursors

Nanocrystalline cobalt ferrite as a magnetic black pigment was synthesized via coordinated precursors with a significant decrease of the synthesis temperature using citric acid as a coordinating agent. The structure and properties of the cobalt ferrite powder were characterized by X-ray diffraction (XRD), colorimetric analysis (L*a*b* color parameters), diffuse reflectance spectroscopy and vibr...

The use of diversity for voice-frequency telegraphy on HF radio circuits

Characterization of Copper-Manganese Oxide Catalysts and Their Precursors: Effect of Precipitate Aging upon the Structure and Morphology of Precursors and Catalysts

Copper-manganese oxide catalysts are prepared with an atomic ratio of Cu/Mn=2/1 using a coprecipitation procedure under air atmosphere. The time of aging, i.e., the time that precipitate remains in contact with the precipitating medium, has been varied from 0 (for unaged precursor) to 300 minutes and the effect of precipitate aging time in each atmosphere upon the structure and morphology of di...

Hematopoietic thymocyte precursors: II. Properties of the precursors

The properties of hematopoietic cells which serve as the precursors of cortical thymocytes in irradiated reconstituted mice have been described. These cells have been termed "prothymocytes." They are 10- to 15-mum diameter cells of low buoyant density. They are nonadherent to glass wool and more resistant to the lytic effects of steroids and gamma-irradiation than their progeny. They lack detec...

Autoactivation of thrombin precursors.

Trypsin-like proteases are synthesized as inactive zymogens and convert to the mature form upon activation by specific enzymes, often assisted by cofactors. Central to this paradigm is that the zymogen does not convert spontaneously to the mature enzyme, which in turn does not feed back to activate its zymogen form. In the blood, the zymogens prothrombin and prethrombin-2 require the prothrombi...