No. 78

October 2011

Headline News Innovation and Development

Applied Technology

Basic Science Cooperation between CAS and Local Authorities
Bioscience International Cooperation Brief News Geoscience
Innovation and Development

New Vision Chips Lay Base for Broad Application

Prof. Wu Nanjian¡¯s Research Group of the State Key Laboratory for Superlattices and Microstructures, Institute of Semiconductors, CAS has developed a novel programmable vision chip based on multiple levels of parallel processors (IEEE Journal of Solid-State Circuits (JSSC), VOL.46, NO.9, 2132-2147(2011)). The chip integrated a high speed CMOS image sensor, an array processor of SIMD processing elements, a column of SIMD row processors and an embedded microprocessor unit (MPU). The multiple-levels of processors can execute low-, mid- and high-level image processing algorithms, respectively, which efficiently increases the image-processing performance of the vision chips. The chip optimized the trade-off among image resolution, processing speed and chip area. It can be applied in target tracking, pattern extraction and image recognition. In 2008, the research group developed a programmable vision chip that consists of a two-dimensional (2D) array processor of processing elements (PEs). Each PE corresponded to an image pixel and consists of a photodiode and processing circuit (Journal of Solid-State Circuits (JSSC), 1470(2008)).

Key Tech Leads to Synfuels

It is well known that nearly all iron-based Fischer¨CTropsch catalysts need a definite quantity of alkali promoters to achieve their optimum catalytic activity and selectivity. However, due to the complexity of real catalytic systems, the microscopic understanding of alkali promotion effect is still an elusive and challenging subject. Recently, scientists of the Institute of Coal Chemistry, CAS and the Synfuels of China Co., Ltd. for the first time reported the "morphology control" effect of potassium promoter on iron catalyst, which gives an important guidance in R&D the efficient catalysts. Their density functional theory (DFT) and experimental research revealed that one crucial effect of potassium promoter (K2O) is modifying crystallographic orientation in favor of forming Fe crystallite with abundant high-active facets. DFT calculations indicated that potassium promoter can stabilize Fe (110), (100), (111), (211), (210), (321), (310) at different degree. This stabilizing effect changes the relative rate of crystal growth in different directions, and thus facilitates the formation of small particles with a large percentage of more active facets. For unprompted catalyst, the thermodynamically most stable Fe(110) facet has the largest contribution to the total surface area of Fe crystallite. As the loading of potassium promoter increase, the proportions of Fe (110) and (100) decrease, while the proportions of more active Fe (211) and (310) increase. This finding opens a new perspective for under-standing the promotion effect, and provides an innovative idea for designing efficient catalysts with controllable surface structures. This work is published on Angew Chem Int. Ed. 2011, 50, 7403-7406, which is a great breakthrough once again made by this group after their important finding that the reaction energy and effective barrier of CH4 formation on iron carbides (FexCy) have a linear relationship with the charge of the surface C atom and the d-band center of the surface, respectively (JACS, 2009, 131, 14713-14721).

Quality Solar Cells to be Industrialized

A CAS Knowledge Innovation Project entitled ¡°research on new concept high efficient solar cells¡± undertaken by the University of Science and Technology (USTC) has successfully passed the completion evaluation and acceptance check on Sep. 25, 2011. Prof. Hou Jianguo, chief scientist of this project and his colleagues addressed key scientific issues in the new concept solar photovoltaic devices and flexible solar cells through innovations on structure, mechanism and material, which include: construction of 78¡Á78mm and 156¡Á156mm visible and near-infrared glass laminated luminescent solar concentrators, demonstration of nano CuInSe2/ZnO core-shell structure and multi-excitons process in GaSb(QD)/GaAs, discovery of solar cell polymer with efficiency of 5.4%, and realization of nano inter-penetrating network polymer solar cell with efficiency of 6.64%, etc. With three years of hard work, the researchers have published 173 papers on international journals, such as Chem. Soc. Rev., Accounts Chem. Res., J. Am. Chem. Soc., Adv. Mater. and Adv. Funct. Mater. A total of 28 invention patents have been filed, among which 5 have been granted.

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