Metal–organic frameworks for electronics: emerging second order nonlinear optical and dielectric materials

Metal–organic frameworks (MOFs) have been intensively studied over the past decade because they represent a new category of hybrid inorganic–organic materials with extensive surface areas, ultrahigh porosity, along with the extraordinary tailorability of structure, shape and dimensions. In this highlight, we summarize the current state of MOF research and report on structure–property relationships for nonlinear optical (NLO) and dielectric applications. We focus on the design principles and structural elements needed to develop potential NLO and low dielectric (low-κ) MOFs with an emphasis on enhancing material performance. In addition, we highlight experimental evidence for the design of devices for low-dielectric applications. These results motivate us to develop better low-dielectric and NLO materials and to perform in-depth studies related to deposition techniques, patterning and the mechanical performance of these materials in the future.     

Study of carbon nanotube field effect transistors performance based on changes in gate parameters

Carbon nanotubes are known as an interesting material to be used in the next generations of electronic technology, especially at nano regime. Nowadays, carbon nanotube field effect transistor or CNTFET is one of the promising devices for future electronic applications. A CNTFET which uses carbon nanotube as channel or source/drain region is the most promising candidate for replacing the current silicon transistor technology. The study of modern manufacturing approach and impact of device parameters on its performance is one of the important research fields in nanoelectronics. In this paper we study some aspects of changes in gate parameters at different channel diameters. This paper shows that for small values of diameter, increasing the dielectric constant of gate insulator doesn't help to improve the performance as value of dielectric constant of gate insulator reaches a certain amount. Also, increasing the oxide thickness of gate insulator doesn't always decrease transistor performance. For high diameter values, increasing the thickness up to a certain value improves the transistor performance.     

Synthesis and magnetic property of FeMoO4 nanorods

Monoclinic FeMoO₄ nanorods have been prepared by the hydrothermal method in an acid aqueous solution. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction spectrum, X-ray photoelectron spectra and differential scanning calorimetry are used to characterize the structure, morphology and composition of the sample. The FeMoO₄ nanorods exhibit a ferromagnetic property at room temperature with the coercivity of 31.1 Oe and remnant magnetization of 4.09 × 10⁻³ emu/g, respectively. The magnetic mechanism has been discussed according to the calculated results of electron density of states for FeMoO₄ with consideration of oxygen vacancies by using the Vienna ab initio simulation package.     

Collective cell guidance by cooperative intercellular forces

Cells comprising a tissue migrate as part of a collective. How collective processes are coordinated over large multi-cellular assemblies has remained unclear, however, because mechanical stresses exerted at cell-cell junctions have not been accessible experimentally. We report here maps of these stresses within and between cells comprising a monolayer. Within the cell sheet there arise unanticipated fluctuations of mechanical stress that are severe, emerge spontaneously, and ripple across the monolayer. Within that stress landscape, local cellular migrations follow local orientations of maximal principal stress. Migrations of both endothelial and epithelial monolayers conform to this behaviour, as do breast cancer cell lines before but not after the epithelial-mesenchymal transition. Collective migration in these diverse systems is seen to be governed by a simple but unifying physiological principle: neighbouring cells join forces to transmit appreciable normal stress across the cell-cell junction, but migrate along orientations of minimal intercellular shear stress.     

Thermodynamic Properties of Magnesium-Boron Binary Alloys Determined Using Solid-State Electrochemical Measurements

Metallurgical and Materials Transactions B - This study provides the thermodynamic properties of the Mg-B binary alloys. Experiments were performed to measure the electromotive force (emf) as a...     

Improvement of Grain Size and Dome Height of Microalloyed Steels Using Taguchi Method Based on Grey Relational Grade in Controlled Rolling

An efficient approach was introduced for improving the condition of major controlled rolling process parameters of roughing, finishing and coiling temperatures and optimizing these parameters to obtain minimum grain size and maximum dome height simultaneously. Taguchi method combined with grey relational analysis was applied to achieve optimum grain size and dome height during controlled rolling process. For this purpose, four levels for the above temperatures were chosen and sixteen experiments were conducted based on orthogonal array of Taguchi method. Based on Taguchi approach, signal-to-noise (S/N) ratios were calculated and used in order to obtain the optimum levels for every input parameter. Analysis of variance revealed that finishing and coiling temperatures have the maximum effect on the grain size and dome height of microalloyed steels. The confirmation tests with the optimal levels of parameters indicated that the grain size and dome height of controlled rolled microalloyed steels can be improved effectively through this approach.     

Popularity prediction of movies: from statistical modeling to machine learning techniques

Multimedia Tools and Applications - Film industries all over the world are producing several hundred movies rapidly and grabbing the attraction of people of all ages. Every movie producer is of...     

An empirical comparison of random forest-based and other learning-to-rank algorithms

Pattern Analysis and Applications - Random forest (RF)-based pointwise learning-to-rank (LtR) algorithms use surrogate loss functions to minimize the ranking error. In spite of their competitive...     

Removal of Vanadium from Molten Aluminum—Part III. Analysis of Industrial Boron Treatment Practice

Transition metal impurities (V, Ti, Zr, and Cr) reduce the electrical conductivity of smelter grade aluminum. These impurities are removed in the form of their borides by reacting with added Al-B master alloys i.e., boron treatment. Although, boron treatment is widely used for the production of high purity aluminum alloys in casthouse the fundamental understanding is lacking and published industrial data are limited. In the current study, industrial trials on the removal of impurities were conducted at one of the high purity aluminum alloys producers in Australasia. Kinetics analysis revealed that the rate of reaction is controlled by the mass transfer of impurities in the bulk melt. The measured mass transfer coefficient (k _m) of V and Ti were 1.1 × 10^?4 and 2.6 × 10^?4 m/s respectively, in the naturally stirred molten aluminum. The rate of V and Ti removal was faster compared to Zr and Cr during the boron treatment of smelter grade aluminum. Mass balance analysis revealed that 70 wt pct of V and Ti combined as borides in the first hour of the total 12 hours of boron treatment process. The calculated amount of un-reacted B was approximately 25.5 wt pct of initial amount added that remained in the final alloy. There was no evidence of boride rings formation, although partially dissolved AlB₁₂ particles were observed under scanning electron microscope. Finally, implications for industrial practice are discussed for the improvement of current boron treatment process that include changing the source of boron, multiple stage addition of boron and better stirring of the molten aluminum.