One-dimensional ͑1D͒ WO 2 nanorods were synthesized by hot-filament metal vapor deposition at high-pressure Ar flow without using any catalyst. The 1D WO 2 nanorods grew on the roots and were a few micrometers long and 50-100 nm wide. The x-ray diffraction pattern shows that the as-synthesized 1D WO 2 nanorods are the monoclinic structure in space group P2 1 / c, and the roots are the ␤ tungsten crystal of the cubic structure in space group Im3m. Field-emission-gun transmission electron microscopy images and selected-area electron diffraction patterns further confirm that the monoclinic 1D WO 2 nanorods consist of the ͑011͒ planes and preferentially grow along the ͗011͘ direction. According to these results, an uncatalyzed vapor-solid process is suggested to be the mechanism of growth of the as-synthesized 1D WO 2 nanorods. In comparison with the Raman scattering of three-dimensional WO 2 bulk powders, the Raman bands of the 1D WO 2 nanorod are blueshifted and narrower, indicating phonon confinement associated with the 1D WO 2 nanorod.

This study provides preliminary evidence that acute stress symptoms, assessed in the ED in the immediate aftermath of a traumatic injury, are useful indicators of risk for later posttraumatic stress.

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The high-temperature ferromagnetism in Co-doped ZnO samples fabricated by the standard solid-state reaction method is reported. Additional Cu doping into bulk Zn 0.98 Co 0.02 O is essential to achieve room-temperature ferromagnetism. Structure and composition analyses revealed that cobalt is incorporated into the lattice structure, forming a solid solution instead of precipitates. In the case of Zn 0.97 Cu 0.01 Co 0.02 O, the coercive field measured by a vibrating sample magnetometer at room temperature is 60 Oe. The implication of the effect of Cu doping in bulk Zn 0.98 Co 0.02 O is also discussed.

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