Changing the size and shape of Ge island by chemical etching

Self-assembled Ge islands were grown on Si (1 0 0) substrate by Si2H6-Ge molecular beam epitaxy. Subjected to a chemical etching, it is found that the size and shape (i.e. ratio of height to base width) of Ge islands change with etching time. In addition, the photoluminescence from the etched Ge islands shifted to the higher energy side compared to that of the as-deposited Ge islands. Our results demonstrated that chemical etching can be a way to change the size and shape of the as-deposited islands as well as their luminescence property. (C) 2001 Elsevier Science B.V. All rights reserved.

structuring and manipulating hand-drawn concept maps

Concept maps are an important tool to knowledge organization,representation, and sharing. Most current concept map tools do not provide full support for hand-drawn concept map creation and manipulation, largely due to the lack of methods to recognize hand-drawn concept maps. This paper proposes a structure recognition method. Our algorithm can extract node blocks and link blocks of a hand-drawn concept map by combining dynamic programming and graph partitioning and then build a concept-map structure by relating extracted nodes and links. We also introduce structure-based intelligent manipulation technique of hand-drawn concept maps. Evaluation shows that our method has high structure recognition accuracy in real time, and the intelligent manipulation technique is efficient and effective.

Research on crustal structure and lithosphere property in the Okinawa Trough area

A mass of geological, geophysical and geochemical data and information from the Okinawa Trough area are collected for comprehensive research in the study area from East China to Okinawa Trough and then to Ryukyu Island Are region. According to the seismic tomography result (P and S wave) and the processing result of free-air and Bouguer gravity anomaly and magnetic anomaly data in the study area, the comprehensive interpretation is carried out. The Moho depth distribution of the study area is obtained by the inversion calculation based on gravity data using the Harmonious Series method. The crust properties are analyzed. Meantime, some Cenozoic basalt data from Kuandian (NE China), Hannuoba (North China), Minxi (South China), Penghu Islands (Taiwan Strait), Okinawa Trough and Japan Island Arc regions are chosen to make the comparison research on element- isotopes. The result indicates that the lithosphere thickness in the Okinawa Trough area has obviously decreased, where a Low -velocity layer of upper-mantle has reached the Moho interface and the metasometized asthenosphere has formed. The research result on element- isotopes shows that the characteristic of the crust in the Okinawa Trough area is different from that in East China area and the Ryukyu Island Arc area. It is considered that the crust in the Okinawa Trough area belongs to the transition type, which is quite similar to the feature of the oceanic crust.