Zhang D.-L.,Tianjin University |
Gao J.,Tianjin University |
Valles J.-A.,University of Zaragoza |
Xu C.,Harbin Institute of Technology |
And 3 more authors.
IEEE Journal of Quantum Electronics | Year: 2010
Near-stoichiometric (NS) (Mg:) LiNbO3crystals crystals were grown from melts (Li2O]n}[Nb2O5]=1:1) containing 0.0/0.5, 0.5/0.5, and 1.0/0.5 mol%/mol% MgO/Er2O 3. OH absorption study shows that the optical damage threshold Mg concentration of the Er/Mg-codoped NS crystal is just near 1.0 mol%. Polarized visible and near infrared, and unpolarized mid-infrared (2. 7μ4I11/2→4 13/2) emission spectra of Er3+ ion in these crystals were measured. From measured emission spectra, the emission and absorption cross-section spectra were calculated based upon McCumber theory, and compared with the data of congruent Er:LiNbO3 bulk material and/or Ti-diffused Er:LiNbO3 strip waveguide and the results obtained from the direct unpolarized optical absorption measurements. The 550, 980, and 1530 nm emission lifetimes were also measured, and compared with the Judd-Ofelt theoretical values and the measured values of the congruent material. The results show that the polarized absorption cross-section data derived from the emission spectra are comparable to the unpolarized cross-section data from direct absorption measurements. The emission and absorption cross-sections, their polarization dependences as well as the lifetime all change definitely as the crystal composition shifts from the congruent point to the near-stoichiometry. In the NS crystal, the Er 3+ ion has smaller emission and absorption cross-sections, and longer lifetimes. In contrast, MgO codoping has less effect on the emission and absorption cross-sections, and lifetime. © 2006 IEEE.
Tang H.-F.,Shanxi Medical University |
Tian Q.-P.,Shanxi Medical University |
Li G.-Y.,Bureau of Science and Technology |
Jian X-T.,Bureau of Science and Technology |
And 2 more authors.
Jiegou Huaxue | Year: 2014
The structures of the complexes formed between N-methylol ethanone (model molecule of ceramide) and azacyclopentane-2-one (the model molecule of azone) have been fully optimized at the B3LYP/6-311++G** level. The intermolecular hydrogen bonding interaction energies have been calculated by using the B3LYP/6-311++G**, B3LYP/6-311++G(2df,2p), MP2(full)/6-311++G** and MP2(full)/6-311++G(2df,2p) methods, respectively. The results show that strong O-H⋯O=C, N-H⋯O=C and C-H⋯O=C hydrogen bonds could exist between azacyclopentane-2-one and N-methylol ethanone. The formation of the complexes might change the conformation of ceramide molecule and thus cause better percutaneous permeation for the drugs. This is perhaps the origin of the permeation enhances the activity of azone for medicament, as is in accordance with the experimental results. The hydrogen-bonding interactions follow the order of (a) > (c) > (b) > (d) > (g) ≈ (e) ≈ (i) > (h) > (f). The analyses of frequency, NBO, AIM and electron density shift are used to further reveal the nature of the complex formation. In the range of 263.0~328.0 K, the complex is formed via an exothermic reaction, and the solvent with lower temperature and dielectric constant is favorable to this process. Copyright © 2013 Editorial Board of Chinese Journal of Structurnal Chemistry.
Wang J.,Tsinghua University |
Zhang Y.,Tsinghua University |
Wang Y.,China National Environmental Monitoring Center |
Xu R.,Tsinghua University |
And 3 more authors.
Biosensors and Bioelectronics | Year: 2010
Biochemical oxygen demand (BOD) is one of the most important and widely used parameters for characterizing the organic pollution of water and wastewater. In this paper, a novel reactor-type biosensor for rapid measurement of BOD was developed, based on using immobilized microbial cell (IMC) beads as recognition bio-element in a completely mixed reactor which was used as determining chamber, replacing the traditionally used membrane as recognition bio-element. The IMC beads were freely suspended in the aqueous solution, so the mass transfer resistance for dissolved oxygen and organic compounds significantly reduced, and the quantity of the microbial cells used as recognition element can be easily adjusted, in comparison with the traditional membrane-type BOD biosensor, in which exists a unadjustable contradiction between the quantity of biomass and the thickness of the bio-membrane, thus limiting the stability and the detection limit. This novel kind of BOD biosensor significantly increased the sensitivity of the response, the detecting precision and prolonged the life time of the recognition element. The experimental data showed that the most appropriate temperature for biochemical reaction in the reactor was 30 °C, and the IMC beads could keep the bioactivity for about 70 d at the detecting frequency of 8 times every day. The standard deviation of repeatability and the reproducibility of responses were within ±6.4% and ±5.0%, respectively, which are within acceptable bias limits, and meet the requirement of BOD rapid measurement. © 2009 Elsevier B.V.
Zhao Y.-P.,Nanjing University of Science and Technology |
Zhao J.,Nanjing University of Science and Technology |
Zhao M.,Bureau of Science and Technology
Neurocomputing | Year: 2013
In this paper, combining the spirit of twin hyperplanes with the fast speed of least squares support vector regression (LSSVR) yields a new regressor, termed as twin least squares support vector regression (TLSSVR). As a result, TLSSVR outperforms normal LSSVR in the generalization performance, and as opposed to other algorithms of twin hyperplanes, TLSSVR owns faster computational speed. When coping with large scale problems, this advantage is obvious. To accelerate the testing speed of TLSSVR, TLSSVR is sparsified using a simple mechanism, thus obtaining STLSSVR. In addition to introducing these algorithms above, a lot of experiments including a toy problem, several small and large scale data sets, and a gas furnace example are done. These applications demonstrate the effectiveness and efficiency of the proposed algorithms. © 2013 Elsevier B.V.
Zou J.,Putian College |
Lin J.,Putian College |
Ruan D.,Bureau of Science and Technology
ICCSE 2012 - Proceedings of 2012 7th International Conference on Computer Science and Education | Year: 2012
The semantic web service based on Petri net is described and modeled in this paper firstly. Secondly, Petri net formalized elements is added to web service. Thirdly, in order to put it come into practice, Petri net model is described with XML. Lastly, this paper gave the practice of web service composition. © 2012 IEEE.