Electronic Band-Structure Calculations of Ba8Me x Si46-x Clathrates with Me = Mg,Pd, Ni,Au, Ag,Cu, Zn,Al, Sn

Clathrate materials of AlSi, CuSi or NiSi type consisting of abundant elements have a realistic chance of becoming useful thermoelectrics in the near future, because the rattling effect due to their crystal cage structure provides a large figure of merit ZT even in experiments measured under large temperature gradients. In the search for better thermoelectrics, new element combinations in the clathrate type I structure with cubic space group Pm3n were calculated using VASP ab initio software. Predictions of the Seebeck coefficient were made by checking the electronic band structure and density of states for a large variety of input data. For x values around 4 to 6 in the structural formula Ba₈Me _x Si_46?x the substituents Cu, Au, and Ag are best for good thermoelectric behavior, which is discussed in this paper as a result of the low electron–phonon interaction parameter.     

Observation of Hydrogenated Amorphous Carbon Films by Atomic Force Microscopy

Atomic force microscopy images were made of the surface of CVD hydrogenated amorphous carbon films. The films were deposited from toluene vapor with oxygen additions during deposition, producing very smooth surfaces. Average roughnesses of only 0.5 nm were measured for the films made with oxygen, whereas a surface roughness of 11 nm was obtained for the films deposited without oxygen. The results suggest that sp ²- and sp ³-bonded carbons were removed by oxygen rosion for CVD hydrogenated amorphous carbon films deposited in the presence of oxygen.     

Charge transport in vacuum-sublimed films of metal-free tetraphenylporphyrin and its relation to capacitance and photocurrent measurements

Drift mobilities (μ) of holes and electrons in vacuum-sublimed films of metal-free tetraphenylporphyrin (H₂TPP) were measured by using a time-of-flight technique with a log-log analysis of photocurrent transients with an electric field (E) and temperature as parameters. Extrapolation of a plot of log μ vs. E^1/2 to E = 0 yielded a very small μ value of the order 10^-16 cm² V^-1 s^-1 for hole and electron transport in the H₂TPP film at 20°C. Field and temperature dependencies of the hole mobilities, analyzed on the basis of the disorder formalism of Bässler and his coworkers, revealed that the extremely slow hole transport in the H₂TPP films was characterized by the largest energetic disorder parameter of 0.22 eV among those reported for other media so far. In addition, measurements of capacitances and photocurrents due to an Al/H₂TPP Schottky junction were carried out with photovoltaic cells of Al/H₂TPP/Au. The lack of dependencies of the capacitances on the frequency and bias voltage was interpreted in terms of the low mobilities of holes in the H₂TPP films. A marked increase of photocurrents with time paralleled a mobility increase, suggesting an important role of carrier mobilities in the mechanism of photocurrent generation in molecular semiconductors.     

Schottky diode design for low-voltage rectification

Barrier height and impurity concentration of a power Schottky diode are optimized for maximum rectifying efficiency in DC-DC converter operation. An optimum barrier-height-impurity-concentration combination is calculated for a given output voltage and diode temperature. For a 1.5 – 2 V output converter, the optimum combination is found to be 17 kT/q and 1.5 × 10¹⁶ cm^?3. Based on the theoretical prediction, titanium- and hafnium-barrier diodes were fabricated as suitable diodes for low-voltage converters and compared with conventionally used molybdenum-barrier diodes. In the experiment on a 2-V output DC-DC converter, the new diodes show higher efficiency than molybdenum diodes at up to 85°C. They are fit for use in encapsulated converters because of their smaller heat generation.     

InGaAs Geiger-mode three-dimensional image sensor for flash LIDAR

Three-dimensional (3D) image sensors are requested by planetary explorers to detect obstacles around landing sites during the landing process and to measure the relative distance and attitude of an orbiting spacecraft during rendezvous docking procedures. Three-dimensional image sensors are also requested in many other fields, including as sensors for autonomous vehicles. In flash LIDAR, a sensor acquires 3D images using the diffuse emission of a pulsed laser, making it suitable for applications like obstacle detection and terrain measurement. We fabricated a prototype 3D image sensor with a temporal resolution of 500 ps and dimensions of 128 × 128 pixels using an InGaAs Geiger mode avalanche photodiode, which is capable of counting photons in the eye-safe band, as the light receiving sensor. This report gives an overview of the prototype sensor and its functions, a detailed evaluation of its time measurement performance, and details of imaging experiments under sunlight.     

Dynamically controlled fibrillation under combination of ionic liquid with mechanical grinding

Combination of mortar grinder mill (MG) and ionic liquid (IL) treatment was employed in order to fibrillate fibers from oil palm mesocarp fiber (OPMF) in one‐step. The structural changes of OPMF before and after the treatment were examined by Thermogravimetric analysis (TGA), Fourier transformed infrared (FT‐IR) spectra, Wide‐angle X‐ray diffraction (WAXD), Dynamic light scattering (DLS) and Scanning electron microscopy (SEM). Compared with the only use of 1‐butyl‐3‐methylimidazolium tetrafluoroborate (BMIM[BF₄]), combination of MG and IL helped to remove hemicellulose and lignin components partially from OPMF, and also fibrillated OPMF fibers at average particle diameter of 127 nm. Afterwards, the fibrillated fibers were utilized as reinforcement material for the purpose of enhancement of mechanical properties of poly(?‐caprolactone)(PCL). The addition of OPMF treated with the combined method led to a 64% increase in tensile strength in comparison with that of untreated OPMF. These results indicate that the combined method enables effective fibrillation. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44469.     

Porous alumina ceramics for slip casting molds

Although a slip cast process using a gypsum mold enables large and complicated dense green body to be made, the green body is contaminated with calcium and sulfur impurities from the gypsum mold. In the case of a resin mold, external pressure must be applied due to its poor water wettability. Porous alumina ceramics are used as a mold material for the first time to overcome these problems. The porous alumina ceramics show higher water wettability than gypsum or resin. The porous alumina molds have submicron pores, and provide larger penetration pressure and higher casting rate than gypsum molds.     

Modular Church-Rosser Modulo:The Complete Picture

In Ref.[19], Toyama proved that the union of two confluent term-rewriting systems that share absolutely no function symbols or constants is likewise confluent, a property called modularity. The proof of this beautiful modularity result, technically based on slicing terms into an homogeneous cap and a so called alien, possibly heterogeneous substitution,was later substantially simplified in Refs.[8,12]. In this paper, we present a further simplification of the proof of Toyama's result for confluence, which shows that the crux of the problem lies on two di?erent properties: a cleaning lemma, whose goal is to anticipate the application of collapsing reductions and a modularity property of ordered completion that allows to pairwise match the caps and alien substitutions of two equivalent terms obtained from the cleaning lemma. The approach allows for arbitrary kinds of rules, and scales up to rewriting modulo arbitrary sets of equations.     

Aberrant expression of glycosylation in juvenile gastrointestinal stromal tumors

Most adult gastrointestinal stromal tumors (GIST) are thought to be caused by activating mutations in the KIT or PDGFRA gene. However, many juvenile GIST lack either mutation and are considered to develop with a different pathogenesis. To investigate the molecular characteristics of juvenile GIST, we analyzed the proteome difference in phosphorylated protein between adult and juvenile GIST. Eleven GIST samples (seven adult cases and four juvenile cases lacking either mutation) were analyzed by using immunostaining and LC-MS/MS. Comparative analysis of tyrosine-phosphorylated protein levels showed that juvenile GIST possessed phosphorylated KIT in spite of lacking mutation in the KIT gene. Moreover, downstream signals of KIT were also activated as in adult GIST. Although, SDS-PAGE gels showed that there was a difference of each KIT bands between adult and juvenile GIST, they became the same after removal of N-glycans or sialic acids. Moreover, one of the most typical enzymes, ST6Gal1, which transfers Neu5Ac residues in α2-6 linkage to Gal β1-4GlcNAc units on N-glycans, is significantly less expressed in juvenile GIST. This suggests that the difference in KIT is generated by post-translational modification and may play a role in the progression of juvenile GIST.