scholarly journals A MODEL OF CRYSTALLIZATION PROCESS TAKING INTO ACCOUNT PHASE CHANGES IN FORMATION OF A METALLIC MATERIAL BY LASER FUSION METHOD

Metallurg ◽  
2021 ◽  
pp. 72-77
Author(s):  
A.S. Zhukov ◽  
I.V. Shakirov ◽  
A.V. Olisov ◽  
B.K. Barakhtin ◽  
S.N. Perevislov

2003 ◽  
Vol 3 (3) ◽  
pp. 32-36 ◽  
Author(s):  
Edina Vranić

An increased understanding of the phenomenon of polymorphism should enable pharmaceutical scientists to gain control over the crystallization process in order to selectively obtain the desired polymorph or suppress the growth of an undesired one. Phase changes during processing and scale-up are a problem, which may be avoided by carefully designed initial small-scale studies. The availability of detailed structural data, combined with strategic design of substrates and additives, has led to significant advances in the control over the polymorphs obtained in a particular crystallization. With all the information available from these initial studies, it should be possible to design and to select processing conditions which would give a desired polymorph and maintain the desired form throughout the various stages of drug processing and manufacture.


Author(s):  
J. M. Cowley ◽  
Sumio Iijima

The imaging of detailed structures of crystal lattices with 3 to 4Å resolution, given the correct conditions of microscope defocus and crystal orientation and thickness, has been used by Iijima (this conference) for the study of new types of crystal structures and the defects in known structures associated with fluctuations of stoichiometry. The image intensities may be computed using n-beam dynamical diffraction theory involving several hundred beams (Fejes, this conference). However it is still important to have a suitable approximation to provide an immediate rough estimate of contrast and an evaluation of the intuitive interpretation in terms of an amplitude object.For crystals 100 to 150Å thick containing moderately heavy atoms the phase changes of the electron wave vary by about 10 radians suggesting that the “optimum defocus” theory of amplitude contrast for thin phase objects due to Scherzer and others can not apply, although it does predict the right defocus for optimum imaging.


1983 ◽  
Vol 44 (11) ◽  
pp. 313-318 ◽  
Author(s):  
Masaaki Takashige ◽  
Terutaro Nakamura ◽  
Yutaka Aikawa

Metrologiya ◽  
2020 ◽  
pp. 25-42
Author(s):  
Dmitrii V. Khablov

This paper describes a promising method for non-contact vibration diagnostics based on the use of Doppler microwave sensors. In this case, active irradiation of the object with electromagnetic waves and the allocation of phase changes using two-channel quadrature processing of the received reflected signal are used. The modes of further fine analysis of the resulting signal using spectral or wavelet transformations depending on the nature of the active vibration are considered. The advantages of this non-contact and remote vibration analysis method for the study of complex dynamic objects are described. The convenience of the method for machine learning and use in intelligent systems of non-destructive continuous monitoring of the state of these objects by vibration is noted.


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