scholarly journals Freeze Frames vs. Movies

2014 ◽  
Vol 70 (a1) ◽  
pp. C178-C178
Author(s):  
Carola Müller ◽  
Sven Lidin
Keyword(s):  
Intermetallic Compounds ◽  
Degrees Of Freedom ◽  
Model Building ◽  
Electronic Devices ◽  
Atomic Arrangement ◽  
Modulation Wave ◽  
Structure Solution ◽  
Methodological Errors ◽  
In The Beginning ◽  
Lock In

Sometimes, model building in crystallography is like resolving a puzzle: All obvious symmetrical or methodological errors are excluded, you apparently understand the measured patterns in 3D, but the structure solution and/or refinement is just not working. One such nerve-stretching problem arises from metrically commensurate structures (MCS). This expression means that the observed values of the components of the modulation wave vectors are rational by chance and not because of a lock-in. Hence, it is not a superstructure - although the boundaries between the two descriptions are blurry. Using a superstructure model for a MCS decreases the degrees of freedom, and forces the atomic arrangement to an artificial state of ordering. Just imagine it as looking at a freeze frame from a movie instead of watching the whole film. The consequences in structure solution and refinement of MCS are not always as dramatically as stated in the beginning. On the contrary, treating a superstructure like a MCS might be a worthwhile idea. Converting from a superstructure model to a superspace model may lead to a substantial decrease in the number of parameters needed to model the structure. Further, it can permit for the refinement of parameters that the paucity of data does not allow in a conventional description. However, it is well known that families of superstructures can be described elegantly by the use of superspace models that collectively treat a whole range of structures, commensurate and incommensurate. Nevertheless, practical complications in the refinement are not uncommon. Instances are overlapping satellites from different orders and parameter correlations. Notably, MCS occur in intermetallic compounds that are important for the performance of next-generation electronic devices. Based on examples of their (pseudo)hexagonal 3+1D and 3+2D structures, we will discuss the detection and occurrence of MCS as well as the benefits and limitations of implementing them artificially.

Towards the automatic crystal structure solution of nucleic acids: automated model building using the new CAB program

2021 ◽  
Vol 77 (12) ◽  
Author(s):  
Giovanni Luca Cascarano ◽  
Carmelo Giacovazzo
Keyword(s):  
Nucleic Acids ◽  
Prior Information ◽  
Model Building ◽  
Phase Error ◽  
Heavy Atoms ◽  
Density Maps ◽  
Structure Solution ◽  
Nucleic Acid Structures ◽  
Automated Model Building ◽  
Model Chain

CAB, a recently described automated model-building (AMB) program, has been modified to work effectively with nucleic acids. To this end, several new algorithms have been introduced and the libraries have been updated. To reduce the input average phase error, ligand heavy atoms are now located before starting the CAB interpretation of the electron-density maps. Furthermore, alternative approaches are used depending on whether the ligands belong to the target or to the model chain used in the molecular-replacement step. Robust criteria are then applied to decide whether the AMB model is acceptable or whether it must be modified to fit prior information on the target structure. In the latter case, the model chains are rearranged to fit prior information on the target chains. Here, the performance of the new AMB program CAB applied to various nucleic acid structures is discussed. Other well documented programs such as Nautilus, ARP/wARP and phenix.autobuild were also applied and the experimental results are described.

scholarly journals Infrared Thermography applied to power electron devices investigation

2015 ◽  
Vol 28 (2) ◽  
pp. 205-212 ◽  
Author(s):  
Giovanni Breglio ◽  
Andrea Irace ◽  
Luca Maresca ◽  
Michele Riccio ◽  
Gianpaolo Romano ◽  
...  
Keyword(s):  
Failure Analysis ◽  
Infrared Thermography ◽  
Semiconductor Devices ◽  
Electronic Devices ◽  
Experimental Characterization ◽  
Ir Thermography ◽  
Power Semiconductor ◽  
Power Semiconductor Devices ◽  
Electron Devices ◽  
Lock In

The aim of this paper is to give a presentation of the principal applications of Infrared Thermography for analysis and testing of electrondevices. Even though experimental characterization could be carried out on almost any electronic devices and circuits, here IR Thermography for investigation of power semiconductor devices is presented. Different examples of functional and failure analysis in both transient and lock-in modes will be reported.

scholarly journals A Computational Intelligence Paradigm with Human Computer Interface Learning

2019 ◽  
Vol 9 (2S) ◽  
pp. 384-389
Keyword(s):  
Review Paper ◽  
Electronic Devices ◽  
Computer Interface ◽  
Human Computer Interface ◽  
Human Beings ◽  
Advance Technology ◽  
Physically Challenged ◽  
Lock In ◽  
External Communications ◽  
The Brain

The cognitive Science is the leading technology which works on the principle of Neuroscience. Human Computer Interface is a challenging approach in neurosciences, which is the leading method to handle the brain activities to control external communications with the electronic devices for physically challenged human beings. The various HCI applications are developed with this advance technology. This helps in various patients which are physically challenged or facing the lock in syndrome, a condition where limbs are not functioning to full extent. Therefore, this paper is the review paper to the various EEG signal classification techniques using different taxonomy with techniques like linear, nonlinear, stableubstable, static-discriminant to design various HCI applications.

Miscellaneous Applications of Intermetallic Compounds

MRS Bulletin ◽  
1996 ◽  
Vol 21 (5) ◽  
pp. 50-55 ◽  
Author(s):  
L.McD. Schetky
Keyword(s):  
Intermetallic Compounds ◽  
Metal Matrix ◽  
Heat Storage ◽  
Storage Systems ◽  
Electronic Devices ◽  
Matrix Composites ◽  
Gold Alloys ◽  
Dental Amalgams ◽  
Property Modification ◽  
Nuclear Applications

So ubiquitous are intermetallic compounds (IMCs) in all areas of materials application that examples of their use in industrial, medical, consumer, and military products are almost limitless. We will in this brief discussion attempt to identify some of the more important of these applications, which we categorize as miscellaneous. These include shape-memory alloys (SMAs), gold alloys used in jewelry, dental amalgams, tribology applications, diffusion barriers in electronic devices, elevated-heat storage systems, nuclear applications, metal-matrix composites, and high damping alloys. In some cases, the IMC is present as a precipitate or dispersed particle that provides strengthening or other property modification while in other examples, the IMC is employed in bulk form.

Phased rotation, conformation and translation function: performance with mononucleotides

2008 ◽  
Vol 41 (1) ◽  
pp. 62-67 ◽  
Author(s):  
Frantisek Pavelcik
Keyword(s):  
Nucleic Acid ◽  
Degrees Of Freedom ◽  
Model Building ◽  
Protein Crystallography ◽  
Torsion Angles ◽  
Heavy Atoms ◽  
Promising Tool ◽  
Translation Function ◽  
Nucleic Acid Structures ◽  
Automatic Model Building

A phased rotation, conformation and translation function (PRCTF) is a novel and promising tool for automatic model building in protein crystallography. Its performance has been tested on nucleic acid structures. A mononucleotide fragment of phosphate-to-phosphate type with seven conformation degrees of freedom was used as a search fragment. The position, orientation and internal torsion angles of all localized fragments are refined by a phased flexible refinement. In general, 50 to 93% of the fragments can be found by the PRCTF. Results depend on resolution and phase quality. The ability of the PRCTF to locate bases is significantly lower (3–30%), owing to the lack of heavy atoms. Individual localized fragments can be connected into polynucleotide chains.

The Numerical Research of Two-Degrees-of-Freedom Vortex-Induced Vibrations of Circular Cylinders

2012 ◽  
Vol 204-208 ◽  
pp. 4598-4601
Author(s):  
Jie Li Fan ◽  
Wei Ping Huang
Keyword(s):  
Degrees Of Freedom ◽  
Amplitude Ratio ◽  
Flow Direction ◽  
Cross Flow ◽  
Circular Cylinders ◽  
Two Degrees Of Freedom ◽  
Line Frequency ◽  
Ansys Cfx ◽  
Vortex Induced Vibrations ◽  
Lock In

The two-degrees-of-freedom of vortex-induced vibration of circular cylinders is numerically simulated with the software ANSYS/CFX. The VIV characteristic, in the two different conditions (A/D=0.07 and A/D=1.0), is analyzed. When A/D is around 0.07, the amplitude ratio of the cylinder’s VIV between in-line and cross-flow direction in the lock-in is lower than that in the lock-out. The in-line frequency is twice of that in cross-flow direction in the lock-out, but in the lock-in, it is the same as that in cross-flow direction and the same as that of lift force. When A/D is around 1.0, the amplitude ratio of the VIV between in-line and cross-flow in the lock-in is obviously larger than that in the lock-out. Both in the lock-in and in the lock-out, the in-line frequency is twice of that in cross-flow direction.

scholarly journals Structure for the N-terminal domain of HCV glycoprotein E1

2014 ◽  
Vol 70 (a1) ◽  
pp. C1803-C1803
Author(s):  
Kamel El Omari ◽  
Oleg Iourin ◽  
Jan Kadlec ◽  
Geoff Sutton ◽  
Richard Fearn ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Model Building ◽  
Heavy Atom ◽  
Protein Fold ◽  
X Ray ◽  
Terminal Domain ◽  
Structure Solution ◽  
Phase Extension ◽  
Resolution Model ◽  
Covalently Linked

Single-wavelength anomalous dispersion of sulfur atoms (S-SAD) is an elegant phasing method to determine crystal structures that does not require heavy atom incorporation or selenomethionine derivatization. Nevertheless this technique has been limited by the paucity of the signal at usual X-ray wavelengths, requiring very accurate measurement of the anomalous differences. Here we report the data collection and structure solution of the N-terminal domain of the ectodomain of Hepatitis C virus (HCV) E1, from crystals that diffracted very weakly. By combining the data from 32 crystals it was possible to solve the sulfur substructure and calculate initial maps at 7Å resolution, and after density modification and phase extension, using a higher resolution native dataset, to 3.5Å resolution, model building was achievable. The crystal structure of the N-terminal domain of reveals a complex network of covalently linked intertwined homodimers that do not harbor the expected truncated class II fusion protein fold.

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