The Hubei University , colloquially known in Chinese as Huda was founded in 1931 and is as a key comprehensive university in Hubei Province, People's Republic of China. The University originated in 1931, starting from what was then Hubei Provincial College of Education. Established with approval from the national government, its first director was Huang Jianzhong. The College moved between locations and changed its name several times during its half-century of development. Since 1984, it has been Hubei University. Wikipedia.
Fan C.,Hubei University |
Yang C.,Hubei University
Chemical Society Reviews | Year: 2014
Owing to the electron spin-orbit coupling (SOC) and fast intersystem crossing (ISC), heavy-metal complexes (such as iridium(iii), platinum(ii) and osmium(ii) complexes, etc.) are phosphorescent emitters at room temperature. Since 1998, heavy-metal complexes as phosphors have received considerable academic and industrial attention in the field of organic light-emitting diodes (OLEDs), because they can harvest both the singlet (25%) and triplet (75%) excitons for emission during the electro-generated processes. Among all the visible colors (blue, green, yellow, orange and red), the yellow/orange heavy-metal complexes play an important role for realizing full-color OLEDs as well as high-efficiency white OLEDs, and thus the development of highly efficient yellow/orange heavy-metal complexes is a pressing concern. In this article, we will review the progress on yellow/orange heavy-metal complexes as phosphors in OLEDs. The general principles and useful tactics for designing the yellow/orange heavy-metal complexes will be systematically summarized. The structure-property relationship and electrophosphorescence performance of the yellow/orange heavy-metal complexes in monochromatic phosphorescent OLEDs (PhOLEDs) and white OLEDs (WOLEDs) will be comprehensively surveyed and discussed. © The Royal Society of Chemistry 2014.
Xia J.,Hubei University
Journal of Applied Geophysics | Year: 2014
This overview article gives a picture of multichannel analysis of high-frequency surface (Rayleigh and Love) waves developed mainly by research scientists at the Kansas Geological Survey, the University of Kansas and China University of Geosciences (Wuhan) during the last eighteen years by discussing dispersion imaging techniques, inversion systems, and real-world examples. Shear (S)-wave velocities of near-surface materials can be derived from inverting the dispersive phase velocities of high-frequency surface waves. Multichannel analysis of surface waves-MASW used phase information of high-frequency Rayleigh waves recorded on vertical component geophones to determine near-surface S-wave velocities. The differences between MASW results and direct borehole measurements are approximately 15% or less and random. Studies show that inversion with higher modes and the fundamental mode simultaneously can increase model resolution and an investigation depth. Multichannel analysis of Love waves-MALW used phase information of high-frequency Love waves recorded on horizontal (perpendicular to the direction of wave propagation) component geophones to determine S-wave velocities of shallow materials. Because of independence of compressional (P)-wave velocity, the MALW method has some attractive advantages, such as 1) Love-wave dispersion curves are simpler than Rayleigh wave's; 2) dispersion images of Love-wave energy have a higher signal to noise ratio and more focused than those generated from Rayleigh waves; and 3) inversion of Love-wave dispersion curves is less dependent on initial models and more stable than Rayleigh waves.To derive S-wave velocities of near-surface materials from high-frequency surface waves only utilizes their phase information. Feasibility of using their amplitude information to estimate near-surface quality factors (Qs and/or Qp) has been studied. Attenuation coefficients of high-frequency surface (Rayleigh and/or Love) waves can be calculated from their amplitude. And by inverting attenuation coefficients, it is feasible to obtain quality factors. Similar to inverting phase velocities of Love waves for S-wave velocities, attenuation coefficients of Love waves are independent of Qp, which makes inversion of attenuation coefficients of Love waves to estimate Qs simpler than that of Rayleigh waves.Both MASW and MALW methods to estimate near-surface S-wave velocities are non-invasive, non-destructive, environment-friendly, low-cost, fast, and in situ seismic methods and possess stable and efficient inversion algorithms to invert phase velocities of surface waves. Real world examples demonstrated that near-surface S-wave velocities derived from phase information are reliable and that methods discussed in the paper to estimate near-surface quality factors from amplitude information are feasible. © 2014 Elsevier B.V.
Pan J.,Hubei University |
Chen C.,Hubei University |
Zhuang L.,Hubei University |
Lu J.,Hubei University
Accounts of Chemical Research | Year: 2012
Although the polymer electrolyte fuel cell (PEFC) is a superior power source for electric vehicles, the high cost of this technology has served as the primary barrier to the large-scale commercialization. Over the last decade, researchers have pursued lower-cost next-generation materials for fuel cells, and alkaline polymer electrolytes (APEs) have emerged as an enabling material for platinum-free fuel cells.To fulfill the requirements of fuel cell applications, the APE must be as conductive and stable as its acidic counterpart, such as Nafion. This benchmark has proved challenging for APEs because the conductivity of OH - is intrinsically lower than that of H +, and the stability of the cationic functional group in APEs, typically quaternary ammonia (-NR 3 +), is usually lower than that of the sulfonic functional group (-SO 3 -) in acidic polymer electrolytes.To improve the ionic conductivity, APEs are often designed to be of high ion-exchange capacity (IEC). This modification has caused unfavorable changes in the materials: these high IEC APEs absorb excessive amounts of water, leading to significant swelling and a decline in mechanical strength of the membrane. Cross-linking the polymer chains does not completely solve the problem because stable ionomer solutions would not be available for PEFC assembly.In this Account, we report our recent progress in the development of advanced APEs, which are highly resistant to swelling and show conductivities comparable with Nafion at typical temperatures for fuel-cell operation. We have proposed two strategies for improving the performance of APEs: self-cross-linking and self-aggregating designs. The self-cross-linking design builds on conventional cross-linking methods and works for APEs with high IEC. The self-aggregating design improves the effective mobility of OH - and boosts the ionic conductivity of APEs with low IEC.For APEs with high IEC, cross-linking is necessary to restrict the swelling of the membrane. In our self-cross-linking design, a short-range cross-linker, tertiary amino groups, is grafted onto the quaternary ammonia polysulfone (QAPS) so that the cross-linking process can only occur during membrane casting. Thus, we obtain both the stable ionomer solution and the cross-linked membrane. The self-cross-linked QAPS (xQAPS) possesses a tight-binding structure and is highly resistant to swelling: even at 80 °C, the membrane swells by less than 3%.For APEs with low IEC, the key is to design efficient OH - conducting channels. In our self-aggregating design, long alkyl side-chains are attached to the QAPS. Based on both the transmission electron microscopy (TEM) observations and the molecular dynamics (MD) simulations, these added hydrophobic groups effectively drive the microscopic phase separation of the hydrophilic and hydrophobic domains and produce enlarged and aggregated ionic channels. The ionic conductivity of the self-aggregated QAPS (aQAPS) is three-fold higher than that of the conventional QAPS and is comparable to that of Nafion at elevated temperatures (e.g., greater than 0.1 S/cm at 80 °C). © 2011 American Chemical Society.
Gong S.,Hubei University |
Yang C.,Hubei University |
Qin J.,Hubei University
Chemical Society Reviews | Year: 2012
Phosphorescent polymer light-emitting diodes (PhPLEDs) are promising devices in flat panel displays and solid state lighting sources since they can combine the advantages of the high efficiency of electrophosphorescence and low-cost, large-scale manufacture by using a solution process. However, their efficiencies are generally much lower than those of small-molecule-based devices fabricated by using a thermal deposition approach. One of the major reasons for their low efficiency is that energy is lost by back transfer to a polymer host. This tutorial review gives a brief introduction to the fundamentals of PhPLEDs, and then highlights recent progress in the main approaches to suppress triplet energy back transfer from the phosphor to the polymer host towards realizing highly efficient PhPLEDs. The suppressing mechanisms are discussed, and the achievement of high device efficiencies are demonstrated. Emphasis is placed on the relationships between molecular structure, the extent of suppressing triplet energy back transfer, and device performance. © 2012 The Royal Society of Chemistry.
Liu Q.,Hubei University |
Zhang H.,Hubei University |
Lei A.,Hubei University
Angewandte Chemie - International Edition | Year: 2011
Oxidative carbonylation reactions have attracted broad interest from both academia and industry in recent years. Enormous efforts have gone into the syntheses of carbonate and urea derivatives through the oxidative carbonylation of alcohols and amines. Very recently, organometallic reagents (R-M) and hydrocarbons(R-H) were directly employed as nucleophiles to construct a C-C bond in oxidative carbonylation reactions. This Minireview summarizes this novel type of oxidative carbonylation reaction. © 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
Tao Y.,Hubei University |
Yang C.,Hubei University |
Qin J.,Hubei University
Chemical Society Reviews | Year: 2011
Phosphorescent organic light-emitting diodes (PhOLEDs) unfurl a bright future for the next generation of flat-panel displays and lighting sources due to their merit of high quantum efficiency compared with fluorescent OLEDs. This critical review focuses on small-molecular organic host materials as triplet guest emitters in PhOLEDs. At first, some typical hole and electron transport materials used in OLEDs are briefly introduced. Then the hole transport-type, electron transport-type, bipolar transport host materials and the pure-hydrocarbon compounds are comprehensively presented. The molecular design concept, molecular structures and physical properties such as triplet energy, HOMO/LUMO energy levels, thermal and morphological stabilities, and the applications of host materials in PhOLEDs are reviewed (152 references). © 2011 The Royal Society of Chemistry.
Zhang Z.-J.,Hubei University
Annals of Clinical Biochemistry | Year: 2013
Background: Oxidative stress may play an aetiological role in the development and progression of cardiovascular disease (CVD). However, evidence on its biochemical markers has been controversial. This article aimed to assess the role of F2-isoprostanes, a marker for measuring in vivo lipid oxidation, as a biomarker for CVD, including coronary artery disease, stroke and peripheral artery disease. Methods: A literature search was performed using PubMed and EMBASE (from 1966 to February 2012). Studies that investigated the association between F2-isoprostanes and CVD were eligible. Results: Of the 22 eligible studies retrieved, 20 studies showed a significant association between F2-isoprostanes and CVD. However, to date, there have been only four population-based studies, with one study reporting null association. Although data from prospective studies are ideal to examine a role of such biomarkers in predicting future CVD events, only two studies were prospective. In addition, differences in population characteristics, sample handling/storage and assays, coupled with a lack of confounding adjustment, may all contribute to the enormous variation in previous studies. Conclusions: High levels of F2-isoprostanes in urine or blood may be a non-specific indicator of CVD. However, further population-based studies are needed. In addition, multivariable analyses are required for future studies to control confounding and improve classification accuracy.
Zhu M.,Hubei University |
Yang C.,Hubei University
Chemical Society Reviews | Year: 2013
Organic light-emitting diodes (OLEDs) are competitive candidates for the next generation flat-panel displays and solid state lighting sources. Efficient blue-emitting materials have been one of the most important prerequisites to kick off the commercialization of OLEDs. This tutorial review focuses on the design of blue fluorescent emitters and their applications in OLEDs. At first, some typical blue fluorescent materials as dopants are briefly introduced. Then nondoped blue emitters of hydrocarbon compounds are presented. Finally, the nondoped blue emitters endowed with hole-, electron- and bipolar-transporting abilities are comprehensively reviewed. The key issues on suppressing close-packing, achieving pure blue chromaticity, improving thermal and morphological stabilities, manipulating charge transporting abilities, simplifying device structures and the applications in panchromatic OLEDs are discussed. © 2013 The Royal Society of Chemistry.
Chen L.,Hubei University
Journal of orthopaedic surgery and research | Year: 2014
The purpose of this research is to evaluate the effects of a tourniquet in total knee arthroplasty (TKA). The study was done by randomized controlled trials (RCTs) on the effects of a tourniquet in TKA. All related articles which were published up to June 2013 from Medline, Embase, and Cochrane Central Register of Controlled Trails were identified. The methodological quality of the included studies was assessed by the Physiotherapy Evidence Database (PEDro) scale. The meta-analysis was performed using Cochrane RevMan software version 5.1. Thirteen RCTs that involved a total of 689 patients with 689 knees were included in the meta-analysis, which were divided into two groups. The tourniquet group included 351 knees and the non-tourniquet group included 338 knees. The meta-analysis showed that using a tourniquet in TKA could reduce intraoperative blood loss (weighted mean difference (WMD), -198.21; 95% confidence interval (CI), -279.82 to -116.60; P<0.01) but did not decrease the calculated blood loss (P=0.80), which indicates the actual blood loss. Although TKA with a tourniquet could save the operation time for 4.57 min compared to TKA without a tourniquet (WMD, -4.57; 95% CI, -7.59 to -1.56; P<0.01), it had no clinical significance. Meanwhile, the use of tourniquet could not reduce the possibility of blood transfusion (P>0.05). Postoperative knee range of motion (ROM) in tourniquet group was 10.41° less than that in the non-tourniquet group in early stage (≤ 10 days after surgery) (WMD, -10.41; 95% CI, -16.41 to -4.41; P<0.01). Moreover, the use of a tourniquet increased the risk of either thrombotic events (risk ratio (RR), 5.00; 95% CI, 1.31 to 19.10; P=0.02) or non-thrombotic complications (RR, 2.03; 95% CI, 1.12 to 3.67; P=0.02). TKA without a tourniquet was superior to TKA with a tourniquet in thromboembolic events and the other related complications. There were no significant differences between the two groups in the actual blood loss. TKA with a tourniquet might hinder patients' early postoperative rehabilitation exercises.
Zhang X.,Hubei University
Communications in Mathematical Physics | Year: 2012
In this article we study the fractal Navier-Stokes equations by using the stochastic Lagrangian particle path approach in Constantin and Iyer (Comm Pure Appl Math LXI:330-345, 2008). More precisely, a stochastic representation for the fractal Navier-Stokes equations is given in terms of stochastic differential equations driven by Lévy processes. Based on this representation, a self-contained proof for the existence of a local unique solution for the fractal Navier-Stokes equation with initial data in W 1,p is provided, and in the case of two dimensions or large viscosity, the existence of global solutions is also obtained. In order to obtain the global existence in any dimensions for large viscosity, the gradient estimates for Lévy processes with time dependent and discontinuous drifts are proved. © 2012 Springer-Verlag.