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Jingzhou, China

Chen H.,Yangtze University
Measurement: Journal of the International Measurement Confederation

In this paper, we propose and experimentally demonstrate a pressure sensor based on birefringent single-mode fiber F-P cavity using optical heterodyne. The proof of concept device consists of a light source, a polarizer controller, a modulator, a RF generator, a single-mode fiber Fabry-Perot cavity, a strain inspector, an erbium doped fiber amplifier, a filter, a polarizer, an optical spectrum analyzer, and a digital communication analyzer. The dynamic range of the proposed sensor is explored. The results demonstrate the new concept of fiber pressure sensors and the technical feasibility for pressure measurements. © 2009 Elsevier Ltd. All rights reserved. Source

Yang B.,Yangtze University
Iranian Polymer Journal (English Edition)

The first example of N-tetradecyl-N-methyl-2-pyrrolidonium was synthesized by using bromide as both an ionic liquid and a surfactant in ionic liquid-based microemulsion polymerization of methyl methacrylate under atom transfer radical polymerization at activator generated electron transfer conditions. The polymerization was carried out at room temperature using copper (II) chloride (CuCl2)/hexamethylene tetramine (HMTA) as a catalyst and CCl 4 as an initiator in the absence of surfactant. Ascorbic acid was used as reducing agent. A pseudoternary phase diagram was constructed at 25 C using the water titration method in the presence and absence of hexadecyltrimethylammonium bromide (CTAB). Kinetics experimental results showed that the polymerization proceeded in a controlled/'living' process as evidenced by a linear increase of molecular weights of polymers with monomer conversion with a relatively narrow polydispersity (<1.35) in all cases and M n,GPC values of the resulting polymer were in excellent agreement with the theoretical values M n,th. The polymerization rate increased with the amount of surfactant. However, the polydispersity became broader. The polymerization rate increased with the amount of ligand and decreased with the amount of monomer. In this system, particles of nanoscale (33-51 nm) were prepared. The average particle diameter was found to be affected by the amount of surfactant. The AGET-ATRP of MMA retained the characteristic of living polymerization when the ionic liquid C14MPnBr and catalyst complex were recovered and reused. Living nature of the polymerization was confirmed by the successful homo chain extension experiment. The resultant PMMA was characterized by 1H NMR spectroscopy and gel permeation chromatography techniques. © 2013 Iran Polymer and Petrochemical Institute. Source

Hu H.,Yangtze University
Shiyou Xuebao/Acta Petrolei Sinica

To study porosity evolution of organic-rich shale, five immature shale samples collected from outcrops were analyzed by pyrolyzing them in a thermal simulation experiment. Organic-rich shale samples with different thermal maturities were obtained in the lab and their maturities referred to immature, early bitumen-formation, late bitumen-formation, late oil-formation and oil-cracking stages, respectively. Nano-pores in these five shale samples were then measured on a specific surface area analyzer. A series of nitrogen adsorption isotherms were measured, which showed that nano-pores increase with thermal maturity increasing and so does the porosity in the organic-rich shale, which is obviously different from the porosity evolution in matrix. The porosity changes little at the oil window, but drastically increases in the gas window, which is consistent with calculated value based on the mass balance theory. Therefore, it can be concluded that increase in porosity of the organic-rich shale results dominantly from the organic matter conversion of oil to gas. Source

Yang J.,Yangtze University
Photodermatology, photoimmunology & photomedicine

BACKGROUND/PURPOSE: Based on the observation that increasing skin temperature could improve 5-aminolevulinic acid (ALA) penetration and accumulation of protoporphyrin IX (PpIX) in the ALA-based photodynamic therapy (PDT), this study was designed to investigate how temperature change varied the therapeutic effect of ALA-based PDT in vitro. METHODS: HaCat cells were cultured with or without ALA at various temperatures. ALA uptake and PpIX accumulation were analyzed before laser irradiation as the baseline. After irradiation, cell death and cytokine secretions in the media, including interleukin (IL)-1alpha, tumor necrosis factor (TNF)-alpha and basic fibroblast growth factor (bFGF) were assayed, and the morphological changes were recorded. RESULTS: With increasing temperature, the amount of ALA uptake, intracellular PpIX concentration and cell death increased in both the PDT and the non-PDT groups. Secretions of IL-1alpha, TNF-alpha and bFGF also increased and reached a peak around 44-47 degrees C and then declined at a higher temperature. This biphasic response might be due to protein thermolysis that occurs when cells reach beyond thermal tolerance. CONCLUSIONS: Elevating temperature could augment photodynamic reactions to a certain extent, but adverse effects occurred when cells were overheated. Source

Zhou D.-Q.,Yangtze University
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control

In order to overcome the defects of parameters estimation in traditional GM(1, 1) model by means of least square procedure, and enhance the forecasting accuracy of GM(1, 1) model in middle and long term load forecasting under the conditions of load sudden changing, an estimation method of GM(1, 1) model parameters based on least absolute deviation is presented. In the GM(1, 1) modeling process, this method optimizes the sum of error absolute, and based on object function characteristics of non-differentiability, uses linear programming to estimate the parameters of the model. It is applied to some middle and long term load forecasting and is compared with the traditional GM(1, 1) model. The results show that the mehod has higher forecasting precision. It takes advantages of the benefits of least absolute deviation, which is lightly influenced by singular value and has good robustness. This model avoids the defects of parameters estimation in traditional GM(1, 1) model by means of least square procedure, it is an effective method to the middle and long term load forecast under the conditions of load sudden changing. Source

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