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novel bipolar copolymer combining hole-transporting units, electron-transporting units and light-emitting units (Alq) had been synthesized via free radical copolymerization of N-vinylcarbazole and Alq monomer containing phenothiazine group. The chemical structure and composition of the copolymer were characterized by H NMR, C NMR, FT-IR spectroscopy, and elemental analysis as well as gel permeation chromatography (GPC). The number-average molecular weight ( M) and polydispersity of these copolymers with different Alq contents were around 20000 and 1.4, respectively. The DSC and TGA measurements indicated that the copolymer has excellent thermal stability and high glass transition temperatures ( T). The optical properties of the copolymer in solution and solid state were investigated by UV-vis and photoluminescence (PL) spectra. Additionally, the effects of Alq content, concentration, excitation wavelength and solvent on PL spectra were studied and the results indicated that there exists efficient energy transfer in the process of photoluminescence. The introduction of carbazole and phenothiazine, as hole-transporting groups and energy transfer stages, provides an effective way to improve carries transporting property and energy transfer efficiency, consequently improving luminescence properties of Alq-based copolymer. [ABSTRACT FROM AUTHOR]

Abstract: A series of bipolar copolymers containing quinoline aluminum moieties and N-vinylcarbazole segments exhibited excellent photoluminescence performance and improved hole-transporting ability, were used as light-emitting materials to fabricate polymeric light-emitting devices (PLEDs). Six simple devices with structure of ITO/PEDOT (40nm)/copolymer (80nm)/CsF (1.5nm)/Al (120nm) were fabricated by solution spin-coating. These devices gave dominant yellow-green emission from quinoline aluminum with excellent stability. Together with electrochemical data, the electroluminescence (EL) mechanism of the devices was studied. Moreover, effects of substituted group and quinoline aluminum''s content on the EL properties of the devices were investigated in detail. The results indicate that the device based on the copolymer (P2-1) with substituted group of carbazole and 2mol% quinoline aluminum possess optimal EL properties with a maximum luminance of 487cd/m2 and a peak current efficiency of 0.545cd/A. [Copyright &y& Elsevier]

A new approach of flow injection chemiluminescent immunoassay (FICLIA) with synergistic enhancement was developed. The synergistic action was significant in the chemiluminescence (CL) system of luminol–H2O2–HRP with two enhancers, para-phenylphenol (PPP) and sodium tetraphenylborate (NaTPB). The relative CL intensity was 128.84% stronger (compared to NaTPB alone) and 122.66% stronger (compared to PPP alone) using both enhancers than any one alone (both P<0.001). While the present approach was applied to the determination of rabbit IgG as a model analyte, satisfactory results were obtained in the dynamic range of 2–60 μg l−1 with a detection limit of 0.68 fmol per injection and a precision of 4.7–9.3%, and the recoveries were 92.5–99.4%. The results of rabbit IgG determination accorded with those of radio immunoassay (RIA). The lifetime of the immuno-column was considerably long: one column was applied to more than 200 determinations in 1 month without significant loss of activity. [Copyright &y& Elsevier]

A numerical method is employed to investigate the fluid flowing dynamics in fractured reservoirs in this paper. Owing to the multi-scales and strong heterogeneity, description of fracture network systems plays a significant role for a successful fractured reservoir simulation model. Comparing to previous works, this paper proposes a combination of dual continuum and discrete fracture network (DFN) model, which is used to simulate the flow in reservoirs with multi-scale fractures and proved feasible. In the first part of the paper, implicit flow equations of oil and water phase in fractured reservoirs are established to consider the nonlinearity properties. And then the control volume finite element method based on the unstructured grid system and N-R iteration are used to obtain the numerical solution. Moreover, the accuracy of this simulator is proved to be reasonable by field data; Sensitivity analysis shows that the existences of complex multi-scale fracture networks have great impacts on water flooding. Compared with the homogeneous reservoir, natural fracture (micro and large scale) networks can change the direction and velocity of the waterfront, which finally leads to the more serious water breakthrough, higher water cut and less recovery. The research and the numerical results obtained in this paper can provide theoretical guidance for efficient and scale development of natural fractured reservoirs. [ABSTRACT FROM AUTHOR]

Highlights: [•] A novel model for a multi-fractured horizontal well with SRV is established. [•] Semi-analytical solutions of the well pressure response are obtained. [•] The pressure response of a well in this reservoir is analyzed. [•] The transient rate decline curves are analyzed. [Copyright &y& Elsevier]

• We present efficient closed-form representations of molar entropy and Gibbs free energy for pure substances. • Present molar entropy and Gibbs free energy prediction models are only involving three molecular constants. • We excellently predict molar entropies and Gibbs free energies for the N 2 gas. Nitrogen (N 2) is widely used in oil and gas industry. We report two new efficient closed-form representations for the molar entropy and Gibbs free energy of pure gaseous substances. A comparison of the predicted and experimental values shows that the molar entropies and Gibbs free energies of N 2 can be excellently predicted in the temperature range of 100–6000 K. The present entropy and Gibbs free energy prediction models only require the experimental values of three molecular constants and are away from the utilization of a great number of experimental spectroscopy data. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a “tri-porosity” mathematical model to describe fluid flow from shale gas formation to a multi-fractured horizontal well. The shale gas is stored by either free or adsorption condition: free gas is stored in both the micro-pores in matrix and natural fractures and the adsorption gas is adsorbed on the surface of matrix particles, which will be desorbed into the micro-pores and then flow into the natural fractures. Based on the Langmuir adsorption isotherm theory, we obtained the point source solution in the Laplace space. Using the Stehfest algorithm, the log–log type curves of dimensionless pseudo-pressure and rate decline curves are obtained. We also analyzed the effects of horizontal well length, fracture number and Langmuir volume on type curves. The results obtained in this paper have important significance to understand the transient pressure and rate decline behaviors of multi-fractured horizontal well in this reservoir. [Copyright &y& Elsevier]