Capital Normal University, Chongqing Normal University and Beijing Waitenksin Advanced Technology Co. | Date: 2011-06-14
A method for measuring thickness or defect depth by pulsed infrared thermal wave technology is described. The method includes heating a measured object by pulsed heating devices, and at the same time, obtaining a thermal image sequence on the surface of the measured object by an infrared thermography device, and storing the thermal image sequence in a general-purpose memory. The method also includes multiplying a temperature-time curve at every point of the thermal image sequence by a corresponding time, thereby obtaining a new curve. The method also includes calculating a first-order differential and obtaining a peak time thereof. The method also includes use of one or more formulas to thereby determine the thickness or the defect depth of the measured object.
Liu N.,Capital Normal University |
Ma Z.,Capital Normal University
Biosensors and Bioelectronics | Year: 2014
In this work, an Au-ionic liquid functionalized reduced graphene oxide nanocomposite (IL-rGO-Au) was fabricated via the self-assembly of ionic liquid functionalized reduced graphene oxide (IL-rGO) and gold nanoparticles (AuNPs) by electrostatic interaction. The IL-rGO can be synthesized and stabilized by introducing the cations of the amine-terminated ionic liquids (IL-NH2) into the graphene oxide (GO). With the assistance of IL-NH2, AuNPs were uniformly and densely absorbed on the surfaces of the IL-rGO. The proposed IL-rGO-Au nanocomposite can be used as an immunosensing platform because it can not only facilitate the electrons transfer of the electrode surface but also provide a large accessible surface area for the immobilization of abundant antibody. To assess the performance of the IL-rGO-Au nanocomposite, a sandwich-type electrochemical immunosensor was designed for simultaneous multianalyte detection (carcinoembryonic antigen (CEA) and alpha-fetoprotein (AFP) as model analytes). The chitosan (CS) coated prussian blue nanoparticles (PBNPs) or cadmium hexacyanoferrate nanoparticles (CdNPs) and loaded with AuNPs were used as distinguishable signal tags. The resulting immunosensor exhibited high selectivity and sensitivity in simultaneous determination of CEA and AFP in a single run. The linear ranges were from 0.01 to 100ngmL-1 for both CEA and AFP. The detection limits reached 0.01ngmL-1 for CEA and 0.006ngmL-1 for AFP, respectively. No obvious nonspecific adsorption and cross-talk was observed during a series of analyses to detect target analytes. In addition, for the detection of clinical serum samples, it is well consistent with the data determined by the ELISA, indicating that the immunosensor provides a possible application for the simultaneous multianalyte determination of CEA and AFP in clinical diagnostics. © 2013 Elsevier B.V.
Wang G.,Capital Normal University
Physical Chemistry Chemical Physics | Year: 2011
Armchair graphene nanoribbons and their derived structures containing Stone-Wales defects are investigated using a self-consistent field crystal orbital method based on density functional theory. The investigation indicates that both the nanoribbons and the defective structures are semiconductors. A low concentration of middle Stone-Wales defects generally increases the carrier mobility, calculated using deformation potential theory, while edge Stone-Wales defects decrease it. The largest increment of the carrier mobility is as high as 170%, which is explained by the lighter carrier effective mass with crystal orbital analysis. © the Owner Societies 2011.
Ye N.S.,Capital Normal University
Critical reviews in food science and nutrition | Year: 2012
Chemical compositions in tea leaves are influenced by their growing surrounding, and the content of these components are related to the quality of teas. The determination of the concentration of chemical composition in teas will predict the ranking of teas and indicate the geographical origins. This overview concerns an investigation of analytical methods that are being used for the determination of the geographical origin of tea. The analytical approaches have been subdivided into three groups: spectroscopic techniques, chromatographic techniques, and other techniques. The advantages, drawbacks, and reported applications concerning geographical authenticity are discussed.
Jin Y.,Capital Normal University
Molecular and Cellular Biochemistry | Year: 2011
3,3′-Diindolylmethane (DIM) is a potential cancer preventive phytochemical derived from Brassica vegetables. The effects of DIM on cell-cycle regulation in both estrogen-dependent MCF-7 and estrogen receptor negative p53 mutant MDA-MB-468 human breast cancer cells were assessed in this study. DIM inhibited the breast cancer cell growth in vitro and in vivo, and caused cellcycle arrest by down-regulating protein levels of cell-cycle related kinases CDK1, CDK2, CDK4, and CDK6, as well as Cyclin B1 and Cdc25A. Meanwhile, it was revealed that Ser124 phosphorylation of Cdc25A is primarily responsible for the DIM-induced Cdc25A degradation. Furthermore, treatment of MCF-7 cells with DIM increased miR-21 expression and down-regulated Cdc25A, resulting in an inhibition of breast cancer cell proliferation. These observations collectively suggest that by differentially modulating cellular signaling pathways DIM is able to arrest the cell-cycle progression of human breast cancer cells.
Wang G.,Capital Normal University
Chemical Physics Letters | Year: 2012
Armchair graphene nanoribbons as well as those with hydrogen-passivated or hydrogen-saturated edges are investigated by using self-consistent field crystal orbital method based on density functional theory. The investigation indicates that different band gap alterations and polarity behaviors with respect to the width exist in these nanoribbons. The carrier mobilities obtained under deformation potential theory decrease with the addition of edge-hydrogens, but are still in the same order. However, edge-hydrogen passivation could be helpful to reduce edge disorder and degradation of carrier mobilities. © 2012 Elsevier B.V. All rights reserved.
Liu Z.,Capital Normal University |
Ma Z.,Capital Normal University
Biosensors and Bioelectronics | Year: 2013
A conducting long-chain polythiols (poly (2-aminothiophenol), PATP) was synthesized by a chemical polymerization process and combined with Au nanoparticles (AuNPs) to prepare a novel, sensitive and label-free electrochemical biosensor by adsorption of carcinoembryonic antibody (anti-CEA) on the PATP-AuNPs modified gold electrode. Differential pulse voltammetry (DPV) was used to characterize the recognition of carcinoembryonic antigen (CEA). Under the optimized conditions, the proposed immunosensor displayed a good amperometric response to CEA with linear range from 1fgmL-1 to 10ngmL-1 and a detection limit of 0.015fgmL-1 (signal/noise=3). The results demonstrated that the immunosensor has advantages of high sensitivity, wide linear range, good repeatability, and good selectivity. Importantly, the results of the detection of clinical serum specimens with the proposed sensor were well consistent with the data determined by micropartical enzyme immunoassay (MPEI), showing that the present work provides a promising ultrasensitive immunoassay strategy for clinical applications. © 2013 Elsevier B.V.
Sun X.,Capital Normal University |
Ma Z.,Capital Normal University
Biosensors and Bioelectronics | Year: 2012
The long-term stability of sensing interfaces is an important issue in biosensor fabrication. A novel stable gold nanoparticle (AuNP)-modified glassy carbon (GC) electrode interface (GC-Ph-AuNP)-based biosensor for detecting carcinoembryonic antigen (CEA) was developed. GC electrodes were modified with 1,4-phenylenediamine to form a stable layer, and then AuNPs were bound onto the GC electrodes through CAu bonds. Anti-CEA was directly adsorbed on AuNPs fixed on the GC electrode. The linear range of the immunosensor was from 10fg to 100ngmL -1 with a detection limit of 3fgmL -1 (S/N=3). The current of the immunosensor was increased by 4% after one month. The GC-Ph-AuNP immunosensor showed high sensitivity, a wide linear range, low detection limit, and good selectivity and stability. The immobilization method of the immunosensor could be widely applied to construct other immunosensors. © 2012 Elsevier B.V.
Capital Normal University | Date: 2012-04-12
This invention relates to a planar optical component and a design method thereof, the method including designing a structure with defined discrete phases; based on the structure with defined discrete phases as array elements, designing a 2D thin antenna array; constituting the planar optical component by a metal film having the 2D thin antenna array and a substrate. To achieve expected beam shaping effect, the method according to the embodiment of the present invention modulates structural parameters of antenna array elements to modulate the amplitude and phase of radiation field having vertical polarization states, which is excited by a beam having specific wavelengths and polarization states incident on the planar diffractive optical component. The planar diffractive optical component according to the embodiment of the present invention has little difference from expected parameters, and can achieve optimum beam shaping effect to make up the shortfall of conventional beam shaping elements.
Capital Normal University | Date: 2013-09-10
A terahertz temporal and spatial resolution imaging system is provided. The system includes: a sample placing rack; a detection crystal, located on the exit side of the sample placing rack; a pump light generating device, for generating a pump light to irradiate the test sample; a terahertz light generating device, for generating a terahertz light to irradiate the test sample, irradiate the detection crystal after obtaining information about the test sample, and modulate an index ellipsoid of the detection crystal; a detection light generating device, for generating a detection light to irradiate the detection crystal to detect the index ellipsoid of the detection crystal, thereby indirectly obtaining the information about the test sample; and an imaging apparatus, located in an optical path after the detection light passes through the detection crystal, for collecting terahertz images of the test sample.