A variety of silicon based multilevel branched submicrometer/ nanostructures, such as branched nanowheatheads, big branched nanowheat-heads, and branched nanowires, have been rationally synthesized via a simple one-step, inexpensive, and catalyst-free fabrication technique. High-resolution transmission electron microscopy studies suggested that the main stem of wheat head and the nanotips of silicon branched nanowheat-heads are single crystals with the preferential growth direction along the [112] and [112] and orientation, respectively. Compared with big branched nanowheat-heads and branched nanowires, the room-temperature Raman frequency of branched nanowheat-heads is blue-shifted and its full width at half-maximum broadens. A moderately strong photoluminescence emission at 550 nm was suggested to be induced by defects, such as stacking faults or the SiOx surface in the branched nanowheat-heads, suggesting potential applications in light-emitting nanodevices. These studies shed light on new opportunities for fabricating different 3-dimensional nanostructures based on their property investigation.

SiC nanorods were synthesized through carbothermal reduction of SiO by C nanocapsules (CNCs) or amorphous activated C (AAC). The synthesized nanorods were characterized by high resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray spectrometry (EDS). The nanorods formed during a reaction between SiO and CNCs were straight. They displayed a preferential orientation of the growth axis; Which was either parallel or normal to the [111] direction. The nanorods formed during reaction between SiO and AAC consisted of straight and curled parts or chains of SiC nanoparticles. The straight parts were aligned in the [111] direction. A surface of the rod tip was covered with a thin amorphous layer, 1～3 nm thick; Containing Si; C and traces of O. Formation mechanism of the SiC nanorods was proposed.

β-SiC nanorods have been synthesized by the reaction of SiO and carbon nano-capsules. For the synthesis of SiC nanorods, it was examined that the reaction temperature and the ratio of SiO to carbon nanocapsules are important and the most appropriate temperature and ratio are around 1380℃ and 5:2, respectively. The synthesized SiC nanorods were characterized by high-resolution electron microscopy. Most of the SiC nanorods are straight and have the diameter of 30-150 nm while the SiC tips of the SiC nanorods have the size 100-400 nm. The SiC nanorods have many stacking faults normal to the [111] direction. Each SiC nanorod has one kind of preferential axis direction, which is either parallel or normal to the [111] direction. Based on the microstructural analysis of the SiC nanorods, a possible growth mechanism of the SiC nanorods is proposed.

The structures and magnetic properties of R,(Fe1-xSix)17 compounds (R=Dy,Y) were investigated by x-ray phase analysis and magnetic measurements. It is shown that Si substitution for Fe leads to a phase transition at x=0.2, and that the mean iron magnetic moment, ufe of R2(Fe1-xSx)17 compounds (R=Dy,Y) decreases as Si concentration x increases; moreover, there is a maximum of dependence Tc(x) at about x=0.16. It is found that the exchange interaction constant AFeFe inR2(Fe1-xSix) compounds (R=Dy, Y) increases with x increasing by means of means-molecular-field analysis of Tc 0 1994 American Institute of Physics.

We report here temperature measurement by means of a Ga-filled C nanotube thermometer with diameter,150 nm and length; 12mm. The method relies on the initial identification and calibration of a nanothermometer in a transmission electron microscope TEM, followed by placing it into an air-filled furnace whose temperature is to be measured, and final TEM reading of a postmeasurement gradation mark visible inside the tubular channel. The mark originates from the fact that, at high temperature, the Ga column tip exposed to the air through the open C nanotube end oxidizes, and a thin Ga oxide layer sticks to the nanotube walls upon cooling. The temperature according to this gradation mark coincides closely with nominal furnace temperature controlled by standard means. The method paves the way for practical temperature measurements using a C nanothermometer in air and within spatially localized regions e.g., dimensions of tens of micrometers.