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Search Results: 1 - 10 of 80659 matches for " Hanxing Liu "
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Electrochemical Performance of a Carbon Nanotube/La-Doped TiO2 Nanocomposite and its Use for Preparation of an Electrochemical Nicotinic Acid Sensor
Jing Wu,Hanxing Liu,Zhidong Lin
Sensors , 2008, DOI: 10.3390/s8117085
Abstract: A carbon nanotube/La-doped TiO2 (La-TiO2) nanocomposite (CLTN) was prepared by a procedure similar to a complex/adsorption process. Scanning electron microscopy (SEM) images show that the La-TiO2 distributes on the carbon nanotube walls. The CLTN was mixed with paraffin to form a CLTN paste for the CLTN paste electrode (CLTNPE). The electrochemical characteristics of CLTNPE were compared with that of conventional carbon electrodes such as the carbon paste electrode (CPE) and glass carbon electrode (GC). The CLTNPE exhibits electrochemical activity and was used to investigate the electrochemistry of nicotinic acid (NA). The modified electrode has a strong electrocatalytic effect on the redox of NA. The cyclic voltammetry (CV) redox potential of NA at the CLTNPE is 320 mV. The oxidation process of NA on the CLTNPE is pH dependent. A sensitive chronoamperometric response for NA was obtained covering a linear range from 1.0×10-6 mol·L-1 to 1.2×10-4 mol·L-1, with a detection limit of 2.7×10-7 mol·L-1. The NA sensor displays a remarkable sensitivity and stability. The mean recovery of NA in the human urine is 101.8%, with a mean variation coefficient (RSD) of 2.6%.
Nanoindentation Study on Mechanical Properties of Nano-SiO2/Dental Resin Composites  [PDF]
Chao Zha, Jianhua Hu, Ainong Li, Shangyu Huang, Hanxing Liu, Gang Chen, Anqi Lei, Zuoqi Zhang, Bei Li, Zhengzhi Wang
Journal of Materials Science and Chemical Engineering (MSCE) , 2018, DOI: 10.4236/msce.2018.64008
Abstract:
The micro/nano-scale indentation tests were performed to explore the performance of bisphenol-α-glycidyl methacrylate (Bis-GMA)/triethylene glycol dimethacrylate (TEGDMA) dental resin composites. The effect of the filling content of nano-SiO2 particles on the mechanical properties of the dental composites was studied as well. The experimental results showed that the incorporation of the nano-SiO2 particles at low concentrations (up to 10 wt.%) can apparently increase the hardness and elastic modulus of the dental rein composites. The plasticity index indicates a best elastic recovery capability at a proper amount (4 wt.%) of the nanoparticles. Combined with the infrared spectrum, the mechanical enhancement mechanisms of the dental resin composites were analyzed.
Electrochemical Performances of Electroactive Nano-LayeredOrganic-Inorganic Perovskite Containing Trivalent Iron Ion and its Use for a DNA Biosensor Preparation
Jing Wu,Hanxing Liu,Zhidong Lin,Minghe Cao
International Journal of Analytical Chemistry , 2010, DOI: 10.1155/2010/419439
Abstract: A steady nano organic-inorganic perovskite hybrid with Fe(CN)6 (3-AMP = 3-methylaminopyridine) was prepared in the air. The structure is an unusual layered organic-inorganic type. The resulting hybrid enveloped in paraffin to prepare Fe(CN)6 paste electrode (HPE) shows good electrochemical activity and a couple of oxidation and reduction peaks with potential of cyclic voltammometry (CV) at around 440?mV and 30?mV. Compared with that on CPE, oxidation potential of on HPE shifts negatively 259.7?mV and that of reduction shifts positively 338.7?mV, which exhibits that Fe(CN)6 can accelerate the electron-transfer to improve the electrochemical reaction reversibility. Such characteristics of Fe(CN)6 have been employed to prepare the DNA biosensor. The single-strand DNA (ssDNA) and double-strand DNA (dsDNA) immobilized on HPE, respectively, can improve the square wave voltammometry (SWV) current and SWV potential shifts positively. The effect of pH was evaluated. And there is hybridization peak on SWV curve using HPE immobilized ssDNA in the complementary ssDNA solution. And HPE immobilized ssDNA can be utilized to monitor the DNA hybridization and detect complementary ssDNA, covering range from to ?g/mL with detection limit of ?g/mL. The DNA biosensor exhibits a good stability and reproducibility. 1. Introduction In recent years, layered organic-inorganic perovskite hybrids have attracted great interest of researchers. Organic-inorganic perovskite hybrids offer an important opportunity to combine useful properties from two chemical realms, organic and inorganic compounds, within a single molecular scale composite. Especially, the design and generation of the organic-inorganic self-organized quantum well structure represent an approach to synthesis that offers new horizons in the context of synthetic chemistry and its possible impact on new material technology [1]. The hybrid organoammonium halometallate(II), (RNH3)2MX4, series of layer perovskite structures have played a significant role in the development of the understanding of low-dimensional magnetic systems and, more recently, of semiconducting, optical, photoelectric materials [2–6]. So far, only organic-inorganic perovskite hybrids containing the chemical element of tin (Sn), copper (Cu), and lead (Pb) have been used to application [7–13]. While it is not reported that organic-inorganic perovskite hybrids were used as electrochemical materials. On the other hand, a few organic-inorganic perovskite hybrids containing M3+ have been reported. As for conventional perovskite frameworks, trivalent metal
Dielectric properties of Y-doped Ba1–xSrxTiO3 ceramics
Jing Xu,HanXing Liu,Bo He,Hua Hao
Optica Applicata , 2010,
Abstract: Y-doped Ba1–xSrxTiO3 (Y-BST) ceramics (x = 0.1, 0.2, 0.4, 0.7) were prepared by solid-state reaction and sintered at 1250, 1300, 1350, and 1400 °C for 1 h. The effect of strontium solution and sintering temperature on the structure, microstructure and dielectric properties of Y-BST was investigated. SEM investigations revealed a grain size decreasing with the Sr content increase. The temperature dependence of permittivity showed decrease in phase transition temperature with higher Sr content. Enhancing sintering temperature is effective to increase the grain size and improve the microstructure porosity. The XRD patterns of all Y-doped Ba0.3Sr0.7TiO3 ceramics indicated that the crystal cell parameters increase when temperature increased. However, the (002) and (200) peaks of Y-doped Ba0.3Sr0.7TiO3 split when sintering temperature was increased to 1400 °C, which makes the structure of the specimen transit to tetragonal (a = 3.9857 and c = 4.018 ) from cubic. It may be attributed to the fact that Y3+ ion can occupy both A site and B site of Ba0.3Sr0.7TiO3 sintered at 1400 °C, which leads to the large different internal stress in individual grains, and then induces the structure change. The temperature coefficient of capacitance (TCC) value of the Y-doped Ba0.3Sr0.7TiO3 sintered at 1400 °C changed little within ±6% over a temperature range from 10 to130 °C.
Synthesis and Structure Transformation of Orthorhombic LiMnO2 Cathode Materials by Sol-gel Method
Synthesis and Structure Transformation of Orthorhombic LiMnO_2 Cathode Materials by Sol-gel Method

Shixi ZHAO,Hanxing LIU,Qiang LI,Shixi OUYANG,
Shixi ZHAO
,Hanxing LIU,Qiang LI and Shixi OUYANG

材料科学技术学报 , 2004,
Abstract: Orthorhombic LiMnO2 cathode materials were synthesized successfully at lower temperature by sol-gel method. When LiMnO2 precursor prepared by sol-gel method was fired in air, the product was a mixture of spinel structure LiMn2O4and rock-salt structure Li2MnO3, whereas in argon single-phase orthorhombic LiMnO2 could obtain at the range of 750℃ to 920℃. The substitution of Mn by Zn2 or Co3 in LiMnO2 led to the structure of LiMnO2 transiting to α-LiFeO2. The results of electrochemical cycles indicated that the discharged capacity of orthorhombic-LiMnO2was smaller at the initial stages, then gradually increased with the increasing of cycle number, finally the capacity stabilized to certain value after about 10th cycles. This phenomenon reveals that there is an activation process for orthorhombic LiMnO2 cathode materials during electrochemical cycles, which is a phase transition process from orthorhombic LiMnO2 to tetragonal spinel Li2Mn2O4. The capacity of orthorhombic LiMnO2 synthesized at lower temperature is larger than that synthesized at high temperature.
Structure and electrical properties of ternary BiFeO3-BaTiO3-PbTiO3 high-temperature piezoceramics
Zhonghua Yao,Ying Liu,Zhe Song,Zhijian Wang,Hua Hao,Minghe Cao,Zhiyong Yu,Hanxing Liu
Journal of Advanced Ceramics , 2012, DOI: 10.1007/s40145-012-0021-1
Abstract: In the current work, the bulk ternary (0.85-x) BiFeO3-xBaTiO3-0.15PbTiO3 (BF-BTx-PT, x=0.08–0.35) system has been studied as a potential high-temperature piezoceramics. Samples with various content of BT were prepared via solid-state route, and pure perovskite phase was confirmed by X-ray diffraction. The temperature dependence of dielectric constants confirmed the decrease of Curie temperature with increasing BT content. It was found that the morphotropic phase boundary (MPB) composition of BF-BTx-PT ceramics was in the vicinity of x=0.15, which exhibits optimal properties with piezoelectric constant d 33 of 60 pC/N, high Curie temperature of 550 °C, and low sintering temperature of 920 °C. Measurements also showed that the depoling temperature was 300 °C, about 150 °C higher than that of commercialized PZT ceramics, which indicated good temperature stability. BF-BTx-PT ceramics are promising candidates for high temperature applications.
Stepwise Confidence Interval Method for MTD Studies with Binomial Populations  [PDF]
Na Yu, Xiaoqing Tang, Hanxing Wang
Engineering (ENG) , 2013, DOI: 10.4236/eng.2013.510B095
Abstract:

Now we extend one method into a sequence of binomial data, propose a stepwise confidence interval method for toxic-ity study, and also in our paper, two methods of constructing intervals for the risk difference are proposed. The first one is based on the well-known conditional confidence intervals for odds ratio, and the other one comes from Santner“small-sample confidence intervals for the difference of two success probabilities”, and it produces exact intervals, through employing our method.

Population-size-dependent branching processes in Markovian random environments
Hanxing Wang,Yonglong Dai
Chinese Science Bulletin , 1998, DOI: 10.1007/BF02883562
Abstract: A branching model |Zn|n≥0 is considered where the offspring distribution of the population’s evolution is not only dependent on the population size, but also controlled by a Markovian environmental process |ξ| n>-0 For this model, asymptotic behaviour is studied such as $\mathop {\lim }\limits_{n \to \infty } Z_n $ and $\mathop {\lim }\limits_{n \to \infty } Z_n /m^n $ in the case that the mean mk,0 of the offspring distribution converges tom > 1 as the population sizek grows to ∞. In the case that |ξ|n≥0 is an irreducible positive recurrent Markov chain, certain extinction (i. c.P(Z n= 0 for somen) = 1) and noncertain extinction (i.e.P(Z n = 0 for somen)< 1) are studied.
Tunable Bending Stiffness, Buckling Force, and Natural Frequency of Nanowires and Nanoplates  [PDF]
Hanxing Zhu, Z. B. Wang, T. X. Fan, D. Zhang
World Journal of Nano Science and Engineering (WJNSE) , 2012, DOI: 10.4236/wjnse.2012.23021
Abstract: This paper aims to obtain the simple closed-form results for the combined effects of surface elasticity, initial stress/ strain, and material Poisson ratio on the bending stiffness, natural frequency and buckling force of nanowires and nano-plates. The results demonstrate that all these properties of nanowires or nanoplates can be designed either very sensitive or not sensitive at all to the amplitude of an applied electric potential; show how much of those properties can be controlled to vary; and thus provide a reliable guide to the measurement of the Young’s modulus of nanowires/nanoplates and to the design of nano-devices, such as nano-sensors or the cantilever of an AFM.
Population-size-dependent branching processes in Markovian random environments

Hanxing Wang,Yonglong Dai,

科学通报(英文版) , 1998,
Abstract: A branching model |Zn|n≥0 is considered where the offspring distribution of the population’s evolution is not only dependent on the population size, but also controlled by a Markovian environmental process |ξ| n>-0 For this model, asymptotic behaviour is studied such as and in the case that the mean mk,0 of the offspring distribution converges tom > 1 as the population sizek grows to ∞. In the case that |ξ|n≥0 is an irreducible positive recurrent Markov chain, certain extinction (i. c.P(Z n= 0 for somen) = 1) and noncertain extinction (i.e.P(Z n = 0 for somen)< 1) are studied.
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