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464 results on '"Zhou, Haiping"'

124. Prediction of Flow Stresses for a Typical Nickel-Based Superalloy During Hot Deformation Based on Dynamic Recrystallization Kinetic Equation

Author

Qin Sheng-xue, Lv Yuting, Liu Jie, Zhou Haiping, and Zhang Hong-bin

Subjects
010302 applied physics, Work (thermodynamics), Materials science, General Engineering, Thermodynamics, 02 engineering and technology, Work hardening, Deformation (meteorology), Strain rate, 021001 nanoscience & nanotechnology, 01 natural sciences, Isothermal process, Superalloy, 0103 physical sciences, Dynamic recrystallization, 0210 nano-technology, Softening
Abstract

The hot deformation behavior of a typical nickel-based superalloy was investigated by isothermal compression tests in the temperature range of 1010∼1160 °C and strain rate range of 0.001∼1 s−1. The results indicate that the work hardening, dynamic recovery (DRV) and dynamic recrystallization (DRX) occurred in the alloy during hot deformation. Considering the coupled effects of deformation parameters on the flow behaviors of the alloy, the constitutive models were established to predict the flow stresses during the work hardening-DRV period and DRX periods. In the DRX period, the modified DRX kinetic equation was used to develop the constitutive models, and the strain for maximum softening rate was used in this equation. Additionally, the material constants in the constitutive models were expressed as the functions of Zener-Hollomon parameter by using a linear fitting method. Meanwhile, comparisons between the measured and the predicted flow stresses were carried out, while the correlation coefficient (R) and average absolute relative error (AARE) between the measured and predicted values were also calculated. The results confirm that the developed models could give an accurate estimation of the flow stresses.

Published
2018

125. Thermal Stability of Nanocrystalline AZ31/TiB2 Magnesium Matrix Composites Prepared via Mechanical Milling.

Author

Zhou, Haiping, Deng, Nana, Zhang, Hongbin, Zhang, Chengcai, Lu, Yue, Gao, Kuidong, Wang, Gang, Sun, Shuai, and Wang, Xin

Subjects
*THERMAL stability, *MECHANICAL alloying, *PRECIPITATION (Chemistry), *MAGNESIUM, *ULTIMATE strength, *COMPRESSIVE strength
Abstract

In this work, the thermal stability of nanocrystalline (NC) AZ31/TiB2 magnesium matrix composites was investigated, while the microstructure evolution and mechanical properties were analyzed. The results indicated the AZ31/TiB2 still maintained NC structure after annealing at 350 °C for 180 min. Even at the high annealing temperature of 400 °C and 450 °C for 180 min, their average grain size just reached about 124 nm and 155 nm, indicating excellent thermal stability. The TiB2 particles with sub-micron size uniformly distributed in Mg matrix had no change in size and no reaction with matrix during the annealing treatment. Due to the strong Zener pinning effect of TiB2 particles, the grain growth of Mg matrix at high temperature was effectively inhibited. Meanwhile, the solution and precipitation behavior of Al atoms were completed in a short time, due to the existence of many grain boundaries and structural defects. By calculation, the grain growth kinetics was described by the kinetics equation D 8 - D 0 8 = k t and the activation energy Eg for grain growth was 131.6 kJ/mol, which was much higher than that of pure Mg (92 kJ/mol). Due to their excellent thermal stability, the decrease in both compressive yield strength and ultimate compressive strength was no more than 12.2% after annealing treatment. Even annealing at 450 °C for 180 min, the CYS and UCS of the samples were still above 283 MPa and 295 MPa, respectively. [ABSTRACT FROM AUTHOR]

Published
2022
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130. Temporally and spatially controllable gene expression and knockout in mouse urothelium

Author

Zhou, Haiping, Liu, Yan, He, Feng, Mo, Lan, Sun, Tung-Tien, and Wu, Xue-Ru

Subjects
Gene expression -- Research, Mice -- Genetic aspects, Mice -- Health aspects, Tissues -- Health aspects, Biological sciences
Abstract

Urothelium that lines almost the entire urinary tract performs important functions and is prone to assaults by urinary microbials, metabolites, and carcinogens. To improve our understanding of urothelial physiology and disease pathogenesis, we sought to develop two novel transgenic systems, one that would allow inducible and urothelium-specific gene expression, and another that would allow inducible and urothelium-specific knockout. Toward this end, we combined the ability of the mouse uroplakin II promoter (mUPII) to drive urothelium-specific gene expression with a versatile tetracycline-mediated inducible system. We found that, when constructed under the control of mUPII, only a modified, reverse tetracycline trans-activator (rtTA-M2), but not its original version (rtTA), could efficiently trans-activate reporter gene expression in mouse urothelium on doxycycline (Dox) induction. The mUPII/rtTA-M2-inducible system retained its strict urothelial specificity, had no background activity in the absence of Dox, and responded rapidly to Dox administration. Using a reporter gene whose expression was secondarily controlled by histone remodeling, we were able to identify, colocalize with 5-bromo-2-deoxyuridine incorporation, and semiquantify newly divided urothelial cells. Finally, we established that, when combined with a Cre recombinase under the control of the tetracycline operon, the mUPII-driven rtTA-M2 could inducibly inactivate any gene of interest in mouse urothelium. The establishment of these two new transgenic mouse systems enables the manipulation of gene expression and/or inactivation in adult mouse urothelium at any given time, thus minimizing potential compensatory effects due to gene overexpression or loss and allowing more accurate modeling of urothelial diseases than previously reported constitutive systems. uroplakin; transgenic; conditional; tetracycline doi: 10.1152/ajprenal.00185.2010.

Published
2010

136. Enhanced Foaming Behavior of Ultrahigh Molecular Weight Polyethylene by Blending Silicone Powder in Microcellular Foaming.

Author

Liu, Jie, Wang, Guilong, Qin, Shengxue, Xu, Xingming, Zhang, Hongbin, and Zhou, Haiping

Subjects
ULTRAHIGH molecular weight polyethylene, FOAM, BLOWING agents, POWDERS, HETEROGENOUS nucleation
Abstract

Microcellular foaming with CO2 as the blowing agent is developed to prepare low‐density ultrahigh molecular weight polyethylene (UHMWPE) foams. To improve the foaming behavior of UHMWPE, silicone powder is used to modify UHMWPE by twin‐screw compounding. The silicone powder contents, foaming temperatures, and foaming pressures are varied to investigate their effect on the foaming behavior of UHMWPE in a one‐step microcellular foaming process. The results show that the addition of silicone powder leads to significantly improved foaming behavior of UHMWPE by simultaneously increasing the expansion ratio and refining cellular morphology. With the presence of silicone powder, UHMWPE with an expansion ratio up to 34‐fold is prepared, while the maximum expansion ratio of pure UHMWPE foam that can be achieved is only 15‐fold. Moreover, for the foams with the same expansion ratio, the presence of silicone powder leads to significantly refined cellular morphology. The improved melt flowability and accelerated crystallization by adding silicone powder are responsible for the significantly enhanced foaming ability of UHMWPE. The heterogeneous nucleation effect of silicone powder plays a critical role in refining the cellular morphology by promoting cell nucleation and reducing cell collapse. [ABSTRACT FROM AUTHOR]

Published
2022
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143. Review of Current Status of III-V MOSFETs

Author

Thayne, Iain, primary, Hill, Richard, additional, Holland, Martin, additional, Li, Xi, additional, Zhou, Haiping, additional, Macintyre, Douglas, additional, Thoms, Stephen, additional, Kalna, Karol, additional, Stanley, Colin, additional, Asenov, Asen, additional, Droopad, Ravi, additional, and Passlack, Matthias, additional

Published
2019
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146. Sustainable production of organic acids via ozonation of biomass derived 5-hydroxymethylfurfural and furfural

Author

Shijie Liu, Shimin Kang, Wenbo Liao, Peifeng Tang, Jinxia Fu, Zhou Haiping, and Wu Xuanhua

Subjects
Maleic acid, 010405 organic chemistry, Formic acid, Pharmaceutical Science, Biomass, Management, Monitoring, Policy and Law, Raw material, 010402 general chemistry, Furfural, 01 natural sciences, Pollution, 0104 chemical sciences, chemistry.chemical_compound, Hydrolysis, chemistry, Succinic acid, Environmental Chemistry, Organic chemistry, Renewable resource
Abstract

Extracting value-added chemicals from renewable resources has attracted much attention in facing the crises arising from fossil resources. This study elucidates a promising strategy of producing valuable organic acids, including maleic acid, formic acid and succinic acid, via a new ozonation process. 5-hydroxymethylfurfural (HMF) and furfural, two platform chemicals obtained from biomass hydrolysis, are used as the raw materials. Under alkaline reaction condition (25 °C, 10 mg/L O3, and 90 min), improved yields of maleic acid, succinic acid and formic acid reached 25.3 wt%, 10.0 wt% and 41.1 wt% from HMF, as well as 17.6 wt%, 2.5 wt% and 79.5 wt% from furfural; respectively. This sustainable manufacturing technology exhibited significant advantages, including one simple process, room condition, avoiding of organic solvent and absence of metal catalysts. This work paves the ways from biomass to commercial organic acids via hydrolysis followed by ozonation.

Published
2021

148. Effect of hydrogen plasma implantation on the micro-structure and magnetic properties of hcp-Co8057Fe4Ir16 thin films.

Author

Wang, Hui, Wu, Meng, Zhou, Haiping, Zhang, Bo, Hu, Shixin, Ma, Tianyong, Li, Zhiwei, Qiao, Liang, Wang, Tao, and Li, Fashen

Subjects
HYDROGEN plasmas, MAGNETIC properties, THIN films, MAGNETIC films, MAGNETIC structure, MICROSTRUCTURE
Abstract

We present detailed investigations of structural and static/dynamic magnetic properties of hydrogenated hcp-Co8057Fe4Ir16 soft magnetic thin films. Two different kinds of defects, i.e., destructive and non-destructive, were demonstrated by controlling the negative bias voltage of the hydrogenation process. Our results show that the structure and magnetic properties of our sample can be tuned by the density of the induced defects. These results provide better understanding of the hydrogenation effect and thus can be used in the future for materials processing to meet the requirements of different devices. [ABSTRACT FROM AUTHOR]

Published
2021
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149. Modulation of the electronic states of perovskite SrCrO3 thin films through protonation via low-energy hydrogen plasma implantation approaches

Author

Wu, Meng, primary, Chen, Shanquan, additional, Huang, Chuanwei, additional, Ye, Xing, additional, Zhou, Haiping, additional, Huang, Xiaochun, additional, Zhang, Kelvin H. L., additional, Yan, Wensheng, additional, Zhang, Lihua, additional, Kim, Kisslinger, additional, Du, Yingge, additional, Chambers, Scott, additional, Zheng, Jin-Cheng, additional, and Wang, Hui-Qiong, additional

Published
2019
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