نتایج جستجو برای: controlled crystallization
تعداد نتایج: 405292 فیلتر نتایج به سال:
The plutonic complex in SE Jersey consists of a late Precambrian gabbro-diorite mass which has been intruded by several granites. The status of the diorites which, like the gabbros, often possess a layered structure, is not clear. New geochemical data, including rare earth and trace element analyses, suggest that acid-basic magma mixing was not responsible for the variety of intermediate rocks....
Controlled induction of crystal nucleation is a highly desirable but elusive goal. Attempts to speed up crystallization, such as high super saturation or working near a liquid-liquid critical point, always led to irregular and uncontrollable crystal growth. Here, we show that under highly nonequilibrium conditions of spinodal decomposition, water crystals grow as thin wires in a template-less f...
A simple and efficient process for the preparation of (±)-9-[(2,3-dihydroxypropoxy)methyl]guanine (isoganciclovir) is described. The synthesis features the preparation of a kinetically and thermodynamically controlled acyclic side chain using masked glycerol and methoxymethyl acetate. The unwanted regioisomers were separated through selective crystallization, which upon deprotection yielded iso...
Crystallization-induced diastereoselective transformation (CIDT) of an α-methyl nitrile completes an entirely non-chromatographic synthesis of the halichondrin B C14-C26 stereochemical array. The requisite α-methyl nitrile substrate is derived from D-quinic acid through a series of substrate-controlled stereoselective reactions via a number of crystalline intermediates that benefit from a rigid...
All bent out of shape: The solvent of crystallization effectively enhances the emission of flexible, bent, π-conjugated molecules in the crystalline state owing to control of the packing of the molecules in the structure. Multichromism such as thermochromism and vapochromism also arises from the solvent-controlled packing. This crystalline-state emission is attributable to the flexibility of cy...
For the polymer-solvent system poly(pheny1enc oxide) in toluenc the mechanism and kinet~cs of crystallization have bccn studied w i f h the Pulsc lnduccd Critical Scattering technique. I t was found that aftcr a dclay-time r the growth mechanism was diffusion controlled. The delay-timc is thought to be conncctcd with the nucleation of thc crystallites and it disappeared in the "sceded" crystall...
Development of facile synthesis strategies for high-quality lanthanidedoped upconversion nanoparticles with controlled composition, crystalline phase, shape, and size is crucial in tuning their chemical and optical properties and exploring their potential applications in diverse fields. This chapter focuses primarily on the formation mechanism of the crystallization (including nucleation and gr...
We have observed 2D protein crystallization under conditions where in the absence of flow, crystallization fails to occur. Even under conditions where crystallization does occur in quiescent systems, we have found that flow can accelerate the crystallization process. By interrogating the flow responsible for this enhanced crystallization, we have correlated the enhancement with large shear in t...
Development of facile synthesis strategies for high-quality lanthanidedoped upconversion nanoparticles with controlled composition, crystalline phase, shape, and size is crucial in tuning their chemical and optical properties and exploring their potential applications in diverse fields. This chapter focuses primarily on the formation mechanism of the crystallization (including nucleation and gr...
Development of facile synthesis strategies for high-quality lanthanidedoped upconversion nanoparticles with controlled composition, crystalline phase, shape, and size is crucial in tuning their chemical and optical properties and exploring their potential applications in diverse fields. This chapter focuses primarily on the formation mechanism of the crystallization (including nucleation and gr...
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