Preparation of novel silica/poly(butylene succinate-co-adipate) organic–inorganic hybrid biodegradable material via sol–gel method

Silica/poly(butylene succinate-co-adipate) organic–inorganic hybrid biodegradable materials were prepared by the sol–gel method. Fourier-transform infrared spectroscopy (FT-IR) and Thermogravimetry/differential thermal analysis (TG/DTA) indicated that the inorganic (SiO₂, C₆H₅SiO_3/2) and organic (PBSA) components were well dispersed in the hybrid material. Heat resistant test shows that the hybrid material was both heat resistant and flexible. The presence of phenyl groups and siloxane network was responsible for the flexibility and heat resistance.     

Dependence of property, cathode characteristics, thermodynamic stability, and average and local structures on heat-treatment condition for LiNi0.5Mn0.5O2 as a cathode active material for Li-ion battery

LiNi_0.5Mn_0.5O₂ was heat-treated under high oxygen-pressure and Ar-reducing conditions, and then the cathode properties, thermodynamic stability and average and local structures were investigated. From X-ray diffraction and ICP measurements, it was found that the pristine LiNi_0.5Mn_0.5O₂ had a single phase of the layered rock-salt structure although the Ni content was slightly rich compared with the nominal one. These characteristics were kept even after the heat-treatments. Charge–discharge cycle tests clarified that the cycle performance of LiNi_0.5Mn_0.5O₂ was improved by both the reducing and oxidizing treatments. From neutron diffraction and X-ray absorption fine structure measurements, the local distortion around the transition metal, especially Ni, was supposed to be one of the important factors to determine the cathode properties. It was also found that the sample with higher thermodynamic stability exhibited better capacity retention in the discharge–charge cycle tests.     

Shielding effect of double microelectrode tips in a scanning electrochemical microscope

Electrochemical interaction of coaxial double microelectrodes, in which a ring microelectrode was surrounded by another ring microelectrode, was investigated. Mass-transfer reactions that occurred on both inner and outer microelectrodes interfered with each other and showed a “shielding” effect depending on potentials and geometries of microelectrodes. Application of the inner microelectrode of the double microelectrodes for a probing tip of a scanning electrochemical microscope (SECM) revealed that the shielding effect by the outer microelectrode affected the electrochemistry on the inner microelectrode in the vicinity of the substrate surface. The effect was intensified above the insulator but attenuated above the conductor as the microelectrodes approached in feedback mode of the SECM. Approach to a critical interelectrode distance also intensified the shielding effect in the substrate generation/tip collection mode. An SECM line-scan using a platinum/epoxy resin-model substrate was carried out to investigate the shielding effect on current sensitivity and lateral resolution of an SECM image.     

Physicochemical Characterization of Chrysin‐Derivative‐Loaded Nanostructured Lipid Carriers with Special Reference to Anticancer Activity

Homologues long‐chain chrysin derivatives (LCD, C _n: 8–18) were synthesized and incorporated into nanostructured lipid carriers (NLC) with the aim to treat human neuroblastoma. Mutual miscibility and attractive interactions among the NLC components, namely tripalmitin (TP), cetyl palmitate (CP), oleic acid (OA), and the chrysin (CHR) derivatives (LCD) at the air–water interface were assessed by the Langmuir monolayer approach. Optimum combination for the NLC formulations was found to be 2:2:1 (M/M/M) for TP/CP/OA, respectively. NLC formulations, both in the absence and presence of LCD, were characterized by combined dynamic light scattering, electron microscopy, atomic force microscopy, and differential scanning calorimetry. The size and zeta potential of the NLC formulations were found in the range 200–350 nm and ?12 to ?18 mV, respectively. Encapsulation efficiency and release kinetics of CHR and LCD when loaded into NLC were also evaluated. LCD exhibited maximum incorporation, drug‐loading capacity, and sustained release because of its enhanced hydrophobicity. Superior incorporation efficiency and sustained‐release profile of LCD were able to enhance their anticancer activity against human neuroblastoma cell lines, compared to CHR, making them promising agents in combating cancer.     

Distribution of carbon contamination in MgAl2O4 spinel occurring during spark-plasma-sintering (SPS) processing: I – Effect of heating rate and post-annealing

Carbon contamination from the carbon paper/dies during spark-plasma-sintering (SPS) processing was examined in the MgAl₂O₄ spinel. The carbon contamination sensitively changes with the heating rate during the SPS processing. At the high heating rate of 100 °C/min, the carbon contamination having organized structures occurred over almost the entire area from the surface to deep inside the SPSed spinel disk. In contrast, at the slow heating rate of 10 °C/min, the carbon contamination having disordered structures occurred only around the surface area. The carbon phases transform into high pressure CO/CO₂ gases by post-annealing in air and lead to pore formation along the grain junctions. The pore formation significantly occurs at the high heating rate due to the large amount of the contaminant carbon phases. This suggests that if once the carbon contamination was formed in the materials, it is very difficult to remove the carbon phases from the materials.     

In situ binary sol–gel reaction of various trifunctional alkoxysilane in the silane‐grafted polyolefin matrix and its effect upon the mechanical properties

The vinyltrimethoxysilane‐grafted ethylene‐propylene copolymer/trifunctional methoxysilane (EPR‐g‐VTMS/RTMS) composites were prepared via in situ silica sol–gel reactions. Five trifunctional methoxysilane compounds (n‐hexyltrimethoxysilane, n‐decyltrimethoxysilane, n‐tetradecyltrimethoxysilane, n‐octadecyltrimethoxysilane, and phenyltrimethoxysilane) have been selected for this study. The water‐cross‐linked EPR‐g‐VTMS/RTMS composites were characterized by attenuated total reflectance‐Fourier transform infrared spectroscopy, gel content, solid‐state ²⁹Si CP/MAS NMR, wide‐angle x‐ray scattering, tensile strength, and field emission scanning electron microscopy measurements. The type of RTMS additive has a substantial influence on the nature of siloxane band networks and eventually the mechanical tensile properties. This finding suggests that the interaction and/or entanglement between the EPR‐g‐VTMS matrix and the substituent of the RTMS additives are crucial for the modifying mechanical properties. Moreover, for the water‐cross‐linked EPR‐g‐VTMS/CnTMS (n = 6, 10, 14, and 18) composites, the joint evidence provided by attenuated total reflectance‐Fourier transform infrared spectroscopy, ²⁹Si CP/MAS NMR, and wide‐angle x‐ray scattering results suggested the formation of ladder‐type poly(n‐alkyl silsesquioxane)s and the presence of the highly ordered structure with a thickness equal to the length of two n‐alkyl groups in all‐trans conformation. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers.     

A New Slip Frequncy Detector of an Induction Motor Utilizing Rotor Slot Harmonics

A method to detect slip frequency from rotor slot harmonics of a three-phase squirrel-cage induction motor is proposed. The rotor slot harmonic voltage Is obtained by summing the three phase voltages, and after being sampled with a multiple of the stator frequency, it is changed into slip frequency waves, from which a voltage proportional to the slip frequency is obtained. Sophisticated sampling techniques allow elimination of the third harmonic voltage induced in the sum of the three-phase voltages and also allow reduction of time constant of the slip frequency detector. Expenmental results show that the slip frequency detector has a good linearity in the range of slip frequency of about -50 to +30 percent of the stator frequency.     

Enhanced Light Storage of SrAl2O4 Glass‐Ceramics Controlled by Selective Europium Reduction

A luminescent Eu, Dy: SrAl₂O₄ glass‐ceramics with high transparency in the visible region was successfully synthesized using the frozen sorbet technique with the control of O₂ partial pressure () for the oxidation of Eu²⁺ ions. The glass‐ceramics include Eu²⁺, Eu³⁺, and Dy³⁺ ions, and thus exhibits three characteristic types of emission bands, 4f–5d at around 520 nm (Eu²⁺ ions), 4f–4f at 610 nm (Eu³⁺ ions), and 480 nm (Dy³⁺ ions). The Eu, Dy: SrAl₂O₄ glass‐ceramics provide remarkable long‐persistent luminescence under dark condition. The glass‐ceramics also exhibits color‐changing luminescence in the visible region based on their remarkable light storage properties. The luminescent Eu, Dy: SrAl₂O₄ glass‐ceramics using the frozen sorbet technique with control of are promising materials for application in novel photonic and light storage materials.     

Formation of Anatase Porous Ceramics by Hydrothermal Hot-Pressing of Amorphous Titania Spheres

Anatase porous ceramics were produced at low temperatures below 350°C by hydrothermal hot-pressing of amorphous titania consisting of spherical particles prepared by hydrolysis of titanium tetraethoxide. After fine anatase crystals were formed in the original amorphous spheres by hydrothermal hot-pressing, the spherical particles were deformed and the fine anatase crystals flowed into the interstices among the original spheres by compression from outside the autoclave to form a compact with homogeneous distribution of fine pores. The fine anatase crystals in the compacts were bonded together by dissolution and deposition to form a compact with high mechanical strength. The porous anatase ceramics with open pores were prepared by drying in air after removing water which had occupied the pores in the compacts during hydrothermal hot-pressing.     

Humidity Sensor Characteristics of Woodceramics

The humidity sensor characteristics of Woodceramics were investigated. The Woodceramics used in this experiment were prepared at 650–900°C. The size of specimens selected was 1 × 1 × 10 mm . One was used as-cut and the other was polished. Above 700°C, the resistance of the specimen was below 50 and the decrease of resistance with increasing relative humidity was small. The specimen prepared at 650°C had a resistance of about 1 k. The resistance of as-cut specimens decreased with increase in relative humidity, but that of the polished specimen did not change significantly. The difference between as-cut and polished samples was explained by the differences in surface micro-structure.