No abstract

The synthesis of well-aligned titanium dioxide with a very high length-to-diameter ratio is demonstrated for the first time using a solgel method under a magnetic field (up to 9.4 T), with cetyltrimethylammonium bromide as a structure-aligning agent.Titanium dioxide (TiO 2 ) is currently one of the most important, widespread, and investigated materials owing to its low toxicity, high thermal stability, and broad applicability. As a semiconductor, titanium dioxide has shown outstanding performances in photocatalysis, 1 water splitting, 2 and self-cleaning applications. 3 It is also useful in medical applications 4 because of its good biocompatibility. Moreover, titanium dioxide plays a crucial role in dye-sensitized solar cells. 5 Different shapes and sizes of titanium dioxide have been reported to give different effects in various reactions. 6 Significant attention has been paid to the effect of a magnetic field on the nucleation and growth processes of magnetic materials 7,8 and the self-assembly behaviors of molecules. 911 A clear effect of an external magnetic field was shown vividly in the growth of magnetic materials such as Fe and Co, since magnetic materials possess easy magnetic axes. The growth of ferromagnetic materials under a magnetic field produced crystals in a wire formation. 7 Over many years, scientists have developed several methods for the structural control of organized molecular assemblies, such as the use of flow and electric fields. The use of a magnetic field is also a potential method for the alignment and orientation of molecules and domains, because it has the advantage that any materials, even diamagnetic materials, can be aligned as long as they possess magnetic anisotropy. It is well established that diamagnetic assemblies having magnetic anisotropy will become oriented and rotate in a magnetic field to achieve their minimum-energy state. 9 Protocols for producing orientated ordered inorganic surfactants have been reported but are based only on simulation theory. 10 The use of TiO 2 as an inorganic precursor and an organic surfactant, however, has not been reported.Here, well-aligned titanium dioxide was synthesized successfully through a solgel method by using tetra-n-butyl orthotitanate (TBOT) as the titanium dioxide precursor. In a typical experiment, cetyltrimethylammonium bromide (CTAB) was weighed (0.023 mg) and placed into a 5-mL sample bottle. Subsequently, 2-propanol (2.057 mL) and water (0.016 mL) were added to the sample bottle. TBOT as the TiO 2 precursor (0.1 mL) was then added dropwise into the sample bottle. Finally, the solution was transferred quickly into a petri dish and covered with perforated aluminum foil.The petri dish containing TBOT, CTAB, 2-propanol, and water was placed under a magnetic field and allowed to self-dry for 47 days. The relative humidity was 60%. The hydrolysis rate was controlled by varying the apparent area of the liquidair interphase by putting the reaction mixture in narrow-bore and large-bore tubes. A superconducting magnet (Oxford magnet)...

Energy is one of the basic concepts in physics which is included as an abstract concept that is not easily captured by students to its physical properties. Therefore it is necessary to optimize the experimental tool in physics learning, especially in the learning of mechanical energy to facilitate understanding the concept. Technology research is growing rapidly and is able to contextually present abstract phenomena that are sensor-based technology and one of them is an ultrasonic sensor. This study aims to develop a mechanical energy experimental tool using ultrasonic sensors to facilitate students in understanding the concept of energy. The development of the experimental tool used research and development methods. To test the feasibility of the experimental tool developed and the accompanying practicum module, a series of feasibility tests have been carried out including calibration tests, feasibility tests by physicists, and empirical tests by users. The instrument used is a checklist item compiled based on the standard indicators of the feasibility of an experimental tool. The results of the development showed that the experimental tool had a precision percentage of 98.1% and a high accuracy of 99.99% with a value of t = (0.383 ± 383X10 -4 ) s. Based on the feasibility test by physicists 93.75% of indicators as standardized experimental tools have been achieved, as well as the experimental modules fulfilling 90.90% of the standard set. Similar results were also report by users that the experimental tool was feasible to be used in schools' level, but there were still obstacles related to the sensitive nature of ultrasonic sensors with surrounding movements and constraints in making variable variations to be tested which had an impact on the less optimal graphic display.

SiC thin film has been synthesized by using conventional 13.56MHz radio frequency plasma enhanced chemical vapour deposition (PECVD). The mixture of silane (SiH4) and methane (CH4) were used as precursor gases while hydrogen as carrier gas. The SiH4/CH4 ratio and the substrate temperature have been varied in order to examine the reaction of the active species which can produce the Si-C bonding in the deposited film. FTIR spectroscopy was used to analyse the type of bonding and particularly to confirm the existence of Si-C bonding by comparing the spectrums obtained from deposited thin film samples and standard reference sample of bulk SiC single crystal wafer. The existence of Si-C bonding was confirmed and it was slightly shifted from the bulk SiC wafer at around 722cm-1 and 817cm-1.

Cylindrical In x Ga 1-x As nanowires (NWs) perpendicular to the substrate have been successfully grown using MOCVD. Morphology of In x Ga 1-x As NWs has been observed using Field Emission-Scanning Electron Microscopy (FE-SEM) and Transmission Electron Microscopy (TEM). Both FE-SEM and TEM results show that the NWs grown at low growth temperature and V/III ratio were via direct impinging mechanism. Energy Dispersive X-ray spectroscopy (EDX) results confirm that the cylindrical NWs grown via direct impinging mechanism and tends to have uniform chemical composition.