Graduate University of Chinese Academic of Science

Beijing, China

Graduate University of Chinese Academic of Science

Beijing, China
Time filter
Source Type

Zuo Q.,CAS Institute of Physics | Zuo Q.,Graduate University of Chinese Academic of science | Gao S.,CAS Institute of Physics | Gao S.,Chinese Academy of Meteorological Sciences | Lu D.,CAS Institute of Physics
Advances in Atmospheric Sciences | Year: 2012

The local features of transient kinetic energy and available potential energy were investigated using ECMWF (European Centre for Medium-Range Weather Forecasts) Interim Reanalysis data for the stratospheric sudden warming (SSW) event of January 2009. The Western Europe high plays important roles in the propagation of the energy from North America to Eurasian. When the Western Europe high appeared and shifted eastward, energy conversions increased and energy propagated from North America to Eurasian as a form of interaction energy flow. The baroclinic conversion between transient-eddy kinetic energy (K e) and transient-eddy available potential energy (A e) and the horizontal advection of geopotential height were approximately one order of magnitude less than K e and A e generation terms. So, these terms were less important to this SSW event. © 2012 Chinese National Committee for International Association of Meteorology and Atmospheric Sciences, Institute of Atmospheric Physics, Science Press and Springer-Verlag Berlin Heidelberg.

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.

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.

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.

Yang X.,CAS Beijing National Laboratory for Molecular | Yang X.,Graduate University of Chinese Academic of science | Zhao N.,CAS Beijing National Laboratory for Molecular | Zhou Q.,CAS Beijing National Laboratory for Molecular | And 8 more authors.
Journal of Materials Chemistry | Year: 2012

A facile method was developed to fabricate hollow amino-functionalized organosilica microspheres based on the hydrolysis and condensation of 3-aminopropyltriethoxysilane (APTES) and tetraethoxysilane (TEOS) in an aqueous system without an additional template and catalyst. The hollow hybrid organosilica microspheres obtained have been characterized by scanning electron microscopy, transmission electron microscopy, and N 2 adsorption-desorption measurements. The results of Fourier transform infrared spectroscopy, solid-state NMR spectroscopy, X-ray photoelectron spectroscopy and thermogravimetric analysis displayed the composition of the synthesized hollow microspheres and the presence of amino groups on the surface. A self-templated and self-catalyzed mechanism for the formation of the hollow microspheres is proposed: the protonated APTES acts as both a catalyst for the reaction and a stabilizer for the hydrophobic precursor droplets, while the droplets themselves act as soft templates, and the consumption of the precursors leads to the formation of a hollow structure. The morphology and the size distribution of the organosilica microspheres can be controlled by tuning the composition of the precursors, and the stirring speed, as well as the reaction temperature. The large cavity with an open hole on the shell and the reactive amino groups on the surface of the hybrid organosilica microspheres promise many potential applications. Examples of employing the microspheres as adsorbents and phase change microcapsules have been presented. © 2012 The Royal Society of Chemistry.

Feng S.,Guangzhou Institutes of Biomedicine and Health | Feng S.,Graduate University of Chinese Academic of Science | Cong S.,Guangzhou Institutes of Biomedicine and Health | Cong S.,Graduate University of Chinese Academic of Science | And 26 more authors.
Nucleic Acids Research | Year: 2011

MicroRNAs play an important roles in cell growth, differentiation, proliferation and apoptosis. They can function either as tumor suppressors or oncogenes. We found that the overexpression of miR-192 inhibited ell proliferation in A549, H460 and 95D cells, and inhibited tumorigenesis in a nude mouse model. Both caspase-7 and the PARP protein were activated by the overexpression of miR-192, thus suggesting that miR-192 induces cell apoptosis through the caspase pathway. Further studies showed that retinoblastoma 1 (RB1) is a direct target of miR-192. Over-expression of miR-192 decreased RB1 mRNA and protein levels and repressed RB1-30-UTR reporter activity. Knockdown of RB1 using siRNA resulted in a similar cell morphology as that observed for overexpression of miR-192. Additionally, RB1-siRNA treatment inhibited cell proliferation and induced cell apoptosis in lung cancer cells. Analysis of miRNA expression in clinical samples showed that miR-192 is significantly downregulated in lung cancer tissues compared to adjacent non-cancerous lung tissues. In conclusion, our results demonstrate that miR-192 is a tumor suppressor that can target the RB1 gene to inhibit cell proliferation and induce cell apoptosis in lung cancer cells. Furthermore, miR-192 was expressed at low levels in lung cancer samples, indicating that it might be a promising therapeutic target for lung cancer treatment. © 2011 The Author(s).

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.

Yun J.,Graduate University of Chinese Academic of science | Yu Z.,Graduate University of Chinese Academic of science | Li K.,Graduate University of Chinese Academic of science | Zhang H.,Graduate University of Chinese Academic of science
Journal of Soils and Sediments | Year: 2013

Purpose: Methanotrophs in wetlands are of great importance because up to 90 % of the methane (CH4) produced in such wetlands could be oxidized by methanotrophs before reaching the atmosphere. The Xianghai wetland of Songnen Plain represents an important ecosystem in northeast China. However, methanotrophic characteristics in this ecosystem have not been studied in detail. The aim of this study is to give an overview of methanotrophic diversity and vertical distribution in the sediments of this important wetland. Materials and methods: Sediment cores were collected from three freshwater marshes, each dominated by a particular vegetation type: Carex alata, Phragmites australis and Typha orientalis. The diversity of methanotrophs was studied by phylogenetic analysis of both the 16S rRNA gene and the particulate methane monooxygenase (pmoA) gene. Methanotroph abundance was determined by quantitative PCR (qPCR) targeting the pmoA gene; group-specific pmoA gene quantification was also used to estimate the abundance of each methanotrophic group. Results and discussion: 16S rRNA and pmoA gene homological analysis revealed the presence of type Ia, Ib and II methanotrophs. Novel pmoA sequences distantly affiliated to cultured Methylococcus sp. were detected, implying the existence of novel methanotrophs in the wetland. Most obtained representatives of Methylobacter genus (both 16S rRNA and pmoA genes) were closely clustered in relation to sequences acquired from the Zoige wetland, Tibet and Siberia permafrost soils, therefore suggesting methanotrophs belonging to Methylobacter genus shared characteristics with methanotrophs in cold areas. The dominance of type I methanotrophs (especially the Methylobacter genus) was detected by both clone library analysis and group-specific qPCR assay. The relatively high methanotroph diversity and pmoA copy numbers measured in the T. orientalis marsh sediments indicated that vegetation type played an important role during CH4 oxidation in the wetland. Conclusions: We present the first data set on methanotroph diversity and vertical distribution in the sediments of the Xianghai wetland. DNA sequences information of Methylococcus-like methanotrophs in the wetland will facilitate the isolating of novel methanotrophs from the wetland. In a worldwide context, our study has enriched the database of genotypic diversity of methanotrophs, which will help in the understanding of the geographical distribution of methanotrophic communities. © 2012 Springer-Verlag Berlin Heidelberg.

Yun J.,Graduate University of Chinese Academic of science | Zhuang G.,Chinese Academy of Sciences | Ma A.,Chinese Academy of Sciences | Guo H.,Graduate University of Chinese Academic of science | And 2 more authors.
Microbial Ecology | Year: 2012

The Zoige wetland of the Tibetan Plateau is a high-altitude tundra wetland and one of the biggest methane emission centers in China. In this study, methanotrophs with respect to community structure, abundance, and activity were investigated in peat soils collected in the vicinity of different marshland plants that dominate different regions of the wetland, including Polygonum amphibium, Carex muliensis, and Eleocharis valleculosa (EV). 16S rRNA gene and particulate methane monooxygenase gene (pmoA) clone library sequence data indicated the presence of methanotrophs with two genera, Methylobacter and Methylocystis. Methylococcus, like pmoA gene sequences, were also retrieved and showed low similarity to those from Methylococcus spp. and thus indicates the existence of novel methanotrophs in the Zoige wetland. Quantitative polymerase chain reaction (qPCR) assays were used to measure the abundance of methantrophs and detected 107 to 108 of total pmoA gene copies per gram dry weight of soil in the three marshes. Group-specific qPCR and reverse transcriptase qPCR results found that the Methylobacter genus dominates the wetland, and Methylocystis methanotrophs were less abundant, although this group of methanotrophs was estimated to be more active according to mRNA/DNA ratio. Furthermore, EV marsh demonstrated the highest methanotrophs abundance and activity among the three marshes investigated. Our study suggests that both type I and type II methanotrophs contribute to the methane oxidation in the Zoige wetland. © 2011 Springer Science+Business Media, LLC.

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.

Loading Graduate University of Chinese Academic of Science collaborators
Loading Graduate University of Chinese Academic of Science collaborators