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Chen Q.,CAS Institute of Electronics | Chen Q.,Graduate University of Chinese Academic of Science | Dong H.,CAS Institute of Electronics | Xia S.,CAS Institute of Electronics
Journal of Electronics | Year: 2012

The traditional design of the catalytic combustion gas sensor in Micro ElectroMechanical Systems (MEMS) micro-hotplate employs a Pt resistive track as the micro-heater. The realized structure and fabrication are the key elements of the micro-hotplate. Directly fabrication of micro-pellsitor catalyst is very difficult because of the small dimensions of the active area. In this paper, a novel micro-pellistor was designed by combining micro fabrication technique and nano technology. The supporting beams and micro-hotplate of the micro-pellistor were made of nonoporous alumina film. The active area of the designed and fabricated micro-pellistors ranges from 200×200 μm 2 to 450×300 μm 2. The micro-pellistor was heated by platinum thin film heater and the Pd catalyst was deposited by dipping the PdCl 2 solution on the detecting element. The lowest power consumption is 50 mW at 500 °C and the maximum temperature can reach 900 °C before rupture. The response of the devices to methane is also tested. The new design provides a new way to fabricate micro-pellistor. © 2012 Science Press, Institute of Electronics, CAS and Springer-Verlag Berlin Heidelberg. Source


Li N.,CAS Institute of Computing Technology | Li N.,Graduate University of Chinese Academic of Science | Zhang Z.,CAS Institute of Computing Technology
Gaojishu Tongxin/Chinese High Technology Letters | Year: 2012

To solve the problem that crowd abnormal behavior detection is difficult to be achieved during video surveillance, this paper proposes a crowd behavior analysis method based on velocity field simplification. The method of velocity field simplification uses topological simplification and clustering analysis to extract the information of a crowd, and then uses the information to detect the anomaly in the crowd. The biggest advantage of velocity field simplification method over others is that it does not need the time-consuming training. The proposed method was tested on the detection of three categories of abnormality: crowd formation/dispersal, changes in crowd speed and crowd splitting/merging. The experiments indicate that the proposed method can efficiently extract the main behaviors of crowd motion and the detection results are similar to the ground truth. Source


Ni L.,CAS Chengdu Institute of Optics and Electronics | Ni L.,Graduate University of Chinese Academic of Science | Ren Q.-F.,CAS Chengdu Institute of Optics and Electronics | Liao S.,CAS Chengdu Institute of Optics and Electronics
Guangdian Gongcheng/Opto-Electronic Engineering | Year: 2010

Based on common measurements of refraction, it is found that the precision of minimum deviation condition is better than that of vertical incidence condition according to our analysis of the sensitivity and uncertainty of them. Analysis shows that for the same deviation and apex angle, the uncertainty of the minimum deviation method is only 1/2 of the uncertainty of the vertical incidence method. Another factor which would also effects uncertainty is the bandwidth of optical source. From analyzing dispersion of ZnSe by Herzberger dispersion equation, it is found that the dispersion of ZnSe at the wavelength of 5~10 μm is approximately 5 × 10-4 μm-1. For a given accuracy, the optical source's bandwidth is less than 20 nm. Source


Xue Q.,CAS Institute of Electronics | Xue Q.,Graduate University of Chinese Academic of Science | Bian C.,CAS Institute of Electronics | Tong J.,CAS Institute of Electronics | And 3 more authors.
Microchimica Acta | Year: 2012

A micro FET-based immunosensor was developed for the determination of hemoglobin-A1c (HbA1c). The HbA1c/hemoglobin ratio is an important index in diabetes control. The sensor was fabricated by Complementary Metal-Oxide-Semiconductor Transistor (CMOS) and Micro Electronic Mechanical System (MEMS) techniques. The antibodies were immobilized via mixed self-assembled monolayers (SAMs) on a gold nanofilm. The nanofilm was deposited on a gold electrode by seed-mediated growth and gave a uniform and well distributed coverage. Nonspecific sites and interferences by noise were eliminated by covering the AuNPs with mixed SAMs. Compared to the immunosensor fabricated via the mixed SAMs method without gold nanofilm, the immunosensor displays a more than 2-fold sensitivity. The immunosensor is capable of detecting HbA1c and hemoglobin in hemolyzed and diluted whole blood, and results showed good agreement with the established clinical method. © 2011 Springer-Verlag. Source


He C.,CAS Institute of Computing Technology | He C.,Graduate University of Chinese Academic of Science | Cheng X.-Q.,CAS Institute of Computing Technology | Guo J.-F.,CAS Institute of Computing Technology
Jisuanji Xuebao/Chinese Journal of Computers | Year: 2011

Faceted navigation is effective in reducing information overload in the process of resource identification, by organizing query result into dynamic multi-dimensional categories. Existing approaches allow users to add or delete only one query keyword at each step, which cannot meet the demands for semantic-rich navigation operations. Moreover, the lack of efficient algorithms for generating dynamic categories makes faceted navigation non-scalable to large datasets. This paper proposes a hierarchical concept lattice for modeling the relationship between different navigation states. Then, a series of navigation operations are proposed to support more flexible transitions between navigation states and hence achieve more effective knowledge discovery. To guarantee real-time response, this paper also devises an efficient algorithm L-Miner for mining and indexing the hierarchical concept lattice. L-Miner discovers all the nodes in a depth-first way and updates the edges between all the generated nodes each time a new node is detected. Empirical studies demonstrate that L-Miner is much faster than existing approaches, utilizing a much smaller indexing structure. Source

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