Proteins and direct methods

1991 ◽  
Vol 197 (3-4) ◽  
Author(s):  
Fan Hai-fu ◽  
Hao Quan ◽  
M. M. Woolfson
Keyword(s):  
First Principles ◽  
Figure Of Merit ◽  
Direct Methods ◽  
Large Structure ◽  
Low Resolution ◽  
Figures Of Merit ◽  
Large Structures ◽  
Resolution Data

AbstractConventional direct methods, which work so well for small structures, are less successful for macromolecules. Where it has been demonstrated that a solution might be found using direct methods it is then found that the usual figures of merit are unable to distinguish the few good sets of phases from the large number of sets generated. The reasons for the difficulties with very large structures are considered from a first-principles approach taking into account both the factors of having a large number of atoms and low resolution data. A proposal is made for trying to recognize good phase sets by taking a large structure as a sum of a number of smaller structures for each of which a conventional figure of merit can be applied.

Use of matrix direct methods for low-resolution phase extension for tRNA. Erratum

1977 ◽  
Vol 33 (6) ◽  
pp. 1008-1008
Author(s):  
A. D. Podjarny ◽  
A. Yonath
Keyword(s):  
Direct Methods ◽  
Low Resolution ◽  
Phase Extension

Predicting the thermoelectric figure-of-merit from first principles

2018 ◽  
Vol 5 (4) ◽  
pp. 10227-10234 ◽  
Author(s):  
Ole Martin Løvvik ◽  
Kristian Berland
Keyword(s):  
First Principles ◽  
Figure Of Merit ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure

scholarly journals Long Slit Echelle Spectroscopy of Supernova Remnants in M33

1988 ◽  
Vol 101 ◽  
pp. 193-196
Author(s):  
William P. Blair ◽  
You-Hua Chu ◽  
Robert C. Kennicutt
Keyword(s):  
Supernova Remnants ◽  
Low Resolution ◽  
Low Velocity ◽  
Line Intensities ◽  
Echelle Spectroscopy ◽  
Resolution Data

AbstractWe have obtained long slit echelle spectroscopy for 10 of the brightest supernova remnants in M33 using the KPNO 4 m telescope. The profiles at Hα indicate bulk motions in the range 100–350 km s−1 in these remnants. Nearly all of the objects show signs of contamination by low velocity H II emission at some level. This affects the line intensities measured from low resolution data and may affect diameter measurements of these remnants.

High thermoelectric figure of merit in monolayer Tl2O from first principles

2020 ◽  
Vol 128 (18) ◽  
pp. 185111
Author(s):  
Qingjun Huang ◽  
Jinlong Ma ◽  
Dongwei Xu ◽  
Run Hu ◽  
Xiaobing Luo
Keyword(s):  
First Principles ◽  
Figure Of Merit ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure

scholarly journals Thermoelectric Properties of NiCl3 Monolayer: A First-Principles-Based Transport Study

Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 411
Author(s):  
Jing Liu ◽  
Xiaorui Chen ◽  
Yuhong Huang ◽  
Hongkuan Yuan ◽  
Hong Chen
Keyword(s):  
First Principles ◽  
Carrier Mobility ◽  
Figure Of Merit ◽  
Lattice Thermal Conductivity ◽  
Transport Theory ◽  
Dimensionless Figure Of Merit ◽  
Structural And Electronic Properties ◽  
High Carrier Mobility ◽  
High Carrier ◽  
Potential Matrix

By employing the first-principles-based transport theory, we investigate the thermoelectric performance based on the structural and electronic properties of NiCl 3 monolayer. The NiCl 3 monolayer is confirmed to be a stable Dirac spin gapless semiconductor with the linear energy dispersion having almost massless carrier, high carrier mobility and fully spin-polarization. Further, NiCl 3 monolayer processes the optimum power factor of 4.97 mWm − 1 K − 2 , the lattice thermal conductivity of 1.89 Wm − 1 K − 1 , and the dimensionless figure of merit of 0.44 at room temperature under reasonable carrier concentration, indicating that NiCl 3 monolayer may be a potential matrix for promising thermoelectrics.

scholarly journals Optimisation of confinement in a fusion reactor using a nonlinear turbulence model

2018 ◽  
Vol 84 (2) ◽  
Author(s):  
E. G. Highcock ◽  
N. R. Mandell ◽  
M. Barnes ◽  
W. Dorland
Keyword(s):  
First Principles ◽  
Figure Of Merit ◽  
Large Scale ◽  
Unit Volume ◽  
Fusion Reactor ◽  
Small Scale ◽  
Zonal Flows ◽  
Novel Approach ◽  
First Time ◽  
Turbulent Cascade

The confinement of heat in the core of a magnetic fusion reactor is optimised using a multidimensional optimisation algorithm. For the first time in such a study, the loss of heat due to turbulence is modelled at every stage using first-principles nonlinear simulations which accurately capture the turbulent cascade and large-scale zonal flows. The simulations utilise a novel approach, with gyrofluid treatment of the small-scale drift waves and gyrokinetic treatment of the large-scale zonal flows. A simple near-circular equilibrium with standard parameters is chosen as the initial condition. The figure of merit, fusion power per unit volume, is calculated, and then two control parameters, the elongation and triangularity of the outer flux surface, are varied, with the algorithm seeking to optimise the chosen figure of merit. A twofold increase in the plasma power per unit volume is achieved by moving to higher elongation and strongly negative triangularity.

scholarly journals Improvement of the thermoelectric properties of a MoO3 monolayer through oxygen vacancies

2019 ◽  
Vol 10 ◽  
pp. 2031-2038
Author(s):  
Wenwen Zheng ◽  
Wei Cao ◽  
Ziyu Wang ◽  
Huixiong Deng ◽  
Jing Shi ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Density Of States ◽  
First Principles ◽  
Figure Of Merit ◽  
Oxygen Vacancies ◽  
Transport Theory ◽  
Boltzmann Transport ◽  
Anisotropic Behavior ◽  
Boltzmann Transport Theory

We have investigated the thermoelectric properties of a pristine MoO3 monolayer and its defective structures with different oxygen vacancies using first-principles methods combined with Boltzmann transport theory. Our results show that the thermoelectric properties of the MoO3 monolayer exhibit an evident anisotropic behavior which is caused by the similar anisotropy of the electrical and thermal conductivity. The thermoelectric materials figure of merit (ZT) value along the x- and the y-axis is 0.72 and 0.08 at 300 K, respectively. Moreover, the creation of oxygen vacancies leads to a sharp peak near the Fermi level in the density of states. This proves to be an effective way to enhance the ZT values of the MoO3 monolayer. The increased ZT values can reach 0.84 (x-axis) and 0.12 (y-axis) at 300 K.

scholarly journals An overview of heavy-atom derivatization of protein crystals

2016 ◽  
Vol 72 (3) ◽  
pp. 303-318 ◽  
Author(s):  
Ashley C. W. Pike ◽  
Elspeth F. Garman ◽  
Tobias Krojer ◽  
Frank von Delft ◽  
Elisabeth P. Carpenter
Keyword(s):  
Heavy Atom ◽  
Protein Crystals ◽  
Data Sets ◽  
Low Resolution ◽  
Heavy Atoms ◽  
Density Maps ◽  
Resolution Electron ◽  
First Choice ◽  
First Time ◽  
Resolution Data

Heavy-atom derivatization is one of the oldest techniques for obtaining phase information for protein crystals and, although it is no longer the first choice, it remains a useful technique for obtaining phases for unknown structures and for low-resolution data sets. It is also valuable for confirming the chain trace in low-resolution electron-density maps. This overview provides a summary of the technique and is aimed at first-time users of the method. It includes guidelines on when to use it, which heavy atoms are most likely to work, how to prepare heavy-atom solutions, how to derivatize crystals and how to determine whether a crystal is in fact a derivative.

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