S’ari, Mark published the artcileLow dose scanning transmission electron microscopy of organic crystals by scanning moire fringes, Application of 3-Ethyl 5-methyl 4-(2,3-dichlorophenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate, the main research area is STEM scanning moire fringes organic crystals; Bright field STEM; Dose-limited resolution; Low dose; Organic crystals; Scanning moiré fringes.
In the pharmaceutical industry, it is important to determine the effects of crystallization and processes, such as milling, on the generation of crystalline defects in formulated products. Conventional transmission electron microscopy and scanning transmission electron microscopy (STEM) can be used to obtain information on length scales unobtainable by other techniques, however, organic crystals are extremely susceptible to electron beam damage. This work demonstrates a bright field (BF) STEM method that can increase the information content per unit specimen damage by the use of scanning moire fringes (SMFs). SMF imaging essentially provides a magnification of the crystal lattice through the interference between closely aligned lattice fringes and a scanning lattice of similar spacing. The generation of SMFs is shown for three different organic crystals with varying electron beam sensitivity, theophylline, furosemide and felodipine. The electron fluence used to acquire the BF-STEM for the most sensitive material, felodipine was approx. 3.5 e-/Å2. After one addnl. scan of felodipine (total fluence of approx. 7.0 e-/Å2), the SMFs were no longer visible due to extensive damage caused to the crystal. Irregularity in the SMFs suggested the presence of defects in all the organic crystals. Further effort is required to improve the data anal. and interpretation of the resulting SMF images, allowing more information regarding the crystal structure and defects to be extracted
Micron published new progress about Crocidolite asbestos Role: ANT (Analyte), ANST (Analytical Study). 72509-76-3 belongs to class pyridine-derivatives, name is 3-Ethyl 5-methyl 4-(2,3-dichlorophenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate, and the molecular formula is C18H19Cl2NO4, Application of 3-Ethyl 5-methyl 4-(2,3-dichlorophenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate.