Radiation damage in 4H-SiC samples implanted by 70 keV oxygen ion beams was studied using photoluminescence and electron spin resonance techniques. ESR peak of g = 2.0053 and two zero-phonon lines were observed with the implanted samples. Combined with theoretical calculations, we found that the main defect in the implanted 4H-Si C samples was oxygen-vacancy complex. The calculated defect formation energies showed that the oxygen-vacancy centers were stable in n-type 4H-Si C.Moreover, the V_(Si)O_C^0 and V_(Si)O_C^(-1) centers were optically addressable. The results suggest promising spin coherence properties for quantum information science.
＜正＞ Phosphonate and phosphonamidate peptides are phosphorus analogues of natural peptides. They have been grea...
XU, Jia-Xi FU, Nan-Yan GAO, Yuan-He ZHNAG, Qi-Han DUAN, Li-Fang(Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China)
Over the past decades,there have been many synthesis methods on producing well-defined crystals,due to their enormous application potentials in industrial field.Among them,high temperature gas-phase reactions(HTGR)approach may be one of the most promising processes for fabrication of well-defined crystals with controllable structure,size,shape,and composition.This review is focused on the recent progresses in synthesizing well-defined crystalline TiO2dominated with,respectively,{001}facets and{105}facets,one-dimensional ZnO and SnO2nanorods/nanowires,MoS2nanosheets as well as GaP,InP,and GaAs nanowires via HTGR approach.Although these research works were currently carried out on experimental scale,it is worth to note that the industrial importance of this HTGR approach for design and fabrication of well-defined crystals in the future owing to its advantages of continuous and scalable production with controlled dimensions and low cost.
Hai-Bo JiangLin-Feng PanPeng-Fei LiuWen-Qi FangHua-Gui Yang
Acquiring the size gradation for particle aggregates is a common practice in the granule related industry,and mechanical sieving or screening has been the normal method. Among many drawbacks of this conventional means,the major ones are time-consuming,labor-intensive,and being unable to provide real-time feedback for process control. In this letter,an optical sieving approach is introduced. The two-dimensional images are used to develop methods for inferring particle volume and sieving behavior for gradation purposes. And a combination of deterministic and probabilistic methods is described to predict the sieving behaviors of the particles and to construct the gradation curves for the aggregate sample. Comparison of the optical sieving with standard mechanical sieving shows good correlation.
