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Your search keyword '"Liu, Wenchao"' showing total 114 results
Start Over Author "Liu, Wenchao" Publisher elsevier bv
114 results on '"Liu, Wenchao"'

1. p97 inhibits integrated stress response-induced neuronal apoptosis after subarachnoid hemorrhage in mice by enhancing proteasome function

Author

Cheng, Wenping, primary, Wei, Boyang, additional, Liu, Wenchao, additional, Jin, Lei, additional, Guo, Shenquan, additional, Ding, Mingxiang, additional, Liu, Yanchao, additional, Fan, Haiyan, additional, Li, Ran, additional, Zhang, Xin, additional, He, Xuying, additional, Li, Xifeng, additional, and Duan, Chuanzhi, additional

Published
2024
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14. The crux of bioactive metabolites in endophytic and thermophilic fungi and their proximal prospects in biotechnological and industrial domains

Author

Pushparaj, Karthika, primary, Meyyazhagan, Arun, additional, Bhotla, Haripriya Kuchi, additional, Arumugam, Vijaya Anand, additional, Pappuswamy, Manikantan, additional, Vadivalagan, Chithravel, additional, Hakeem, Khalid Rehman, additional, Balasubramanian, Balamuralikrishnan, additional, Liu, Wenchao, additional, and Mousavi Khaneghah, Amin, additional

Published
2023
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16. Plasma metabolic signatures for intracranial aneurysm and its rupture identified by pseudotargeted metabolomics

Author

Sun, Kaijian, primary, Zhang, Xin, additional, Li, Xin, additional, Li, Xifeng, additional, Su, Shixing, additional, Luo, Yunhao, additional, Tian, Hao, additional, Zeng, Meiqin, additional, Wang, Cheng, additional, Xie, Yugu, additional, Zhang, Nan, additional, Cao, Ying, additional, Zhu, Zhaohua, additional, Ni, Qianlin, additional, Liu, Wenchao, additional, Xia, Fangbo, additional, He, Xuying, additional, Shi, Zunji, additional, Duan, Chuanzhi, additional, and Sun, Haitao, additional

Published
2023
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25. Chinese Society of Clinical Oncology (CSCO): Clinical guidelines for the diagnosis and treatment of pancreatic cancer

Author

Cui, Jiujie, primary, Jiao, Feng, additional, Li, Qi, additional, Wang, Zheng, additional, Fu, Deliang, additional, Liang, Jun, additional, Liang, Houjie, additional, Xia, Tingyi, additional, Zhang, Tao, additional, Zhang, Yang, additional, Dai, Guanghai, additional, Zhang, Zhihong, additional, Wang, Jian, additional, Bai, Yongrui, additional, Bai, Yuxian, additional, Bi, Feng, additional, Chen, Donghui, additional, Cao, Dan, additional, Chen, Jie, additional, Fang, Weijia, additional, Gao, Yong, additional, Guo, Jianwei, additional, Hao, Jihui, additional, Hua, Haiqing, additional, Huang, Xinyu, additional, Liu, Wenchao, additional, Liu, Xiufeng, additional, Li, Da, additional, Li, Ji, additional, Li, Enxiao, additional, Li, Zhiwei, additional, Pan, Hongming, additional, Shen, Lin, additional, Sun, Yongwei, additional, Tao, Min, additional, Wang, Chengfeng, additional, Wang, Fenghua, additional, Xiong, Jianping, additional, Zhang, Taiping, additional, Zhang, Xuebin, additional, Zhan, Xianbao, additional, Zheng, Leizhen, additional, Ren, Gang, additional, Zhang, Tingting, additional, Zhou, Jun, additional, Ma, Qingyong, additional, Qin, Shukui, additional, Hao, Chunyi, additional, and Wang, Liwei, additional

Published
2022
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27. Optimisation of spray-mist-assisted laser machining of micro-structures on CVD diamond coating surfaces

Author

Quan Zheng, Bing Guo, Liu Wenchao, Qingliang Zhao, and Zhenfei Guo

Subjects
010302 applied physics, Materials science, Process Chemistry and Technology, Diamond, 02 engineering and technology, Chemical vapor deposition, engineering.material, 021001 nanoscience & nanotechnology, Laser, 01 natural sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, law.invention, Taguchi methods, Coating, Machining, law, 0103 physical sciences, Materials Chemistry, Ceramics and Composites, engineering, Laser power scaling, Composite material, 0210 nano-technology, Layer (electronics)
Abstract

In this study, micro-grooves were fabricated on a chemical vapour deposition (CVD) diamond coating using spray-mist-assisted laser machining. In this paper, the advantages and characteristics of spray-mist-assisted laser machining are analysed through comparison with other forms of laser machining based on morphology and composition. Meanwhile, the effects of process parameters (laser power, scanning speed, defocusing quantity, air pressure, spray angle, and offset distance) on the machining characteristics were investigated using the Taguchi method, and the optimal parameter range of spray-mist-assisted laser-machined CVD diamond coating was obtained. The results indicate that spray-mist-assisted laser machining can effectively remove the recast layer and ensure the precision and continuity of laser machining. The most significant factor affecting the cross-sectional area of the grooves is laser power, while laser power and scanning speed significantly affect depth-to-width (D/W) ratio of grooves. The spray parameters had no significant effect on the characteristics of ablative grooves because the thickness of the water film formed by spray-wall impingement was relatively thin and stabilised.

Published
2021

34. Preparation of Ti-22Al-25Nb solid solution powders using mechanical alloying and solid solution mechanism analysis

Author

Yan Xu, Sun Wei, Weijin Peng, Zhong Xiaoxiao, Liu Wenchao, Zhigang Yang, Jianbo Jia, and Junting Luo

Subjects
Materials science, Nanocomposite, General Chemical Engineering, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Indentation hardness, 0104 chemical sciences, chemistry.chemical_compound, Chemical engineering, chemistry, Mechanics of Materials, Phase (matter), Particle, Crystallite, Particle size, Stearic acid, 0210 nano-technology, Solid solution
Abstract

Solid solution powders of Ti-22Al-25Nb (at.%) were successfully prepared with Ti, Al, and Nb elemental powders via mechanical alloying (MA). The effects of milling time, stearic acid process control agent and Al2O3 reinforced particles on the morphology evolution, average particle size, crystallite size, solid solution and phase of mixed powders were studied. The solid solution mechanism and strengthening mechanism of Ti, Al and Nb mixed powders during MA were revealed. In addition, the strengthening effect of Al2O3 reinforced particles was clarified. The mixed powders at different milling times were characterized by X-ray diffraction and scanning electron microscopy. The microhardness of the solid solution powders was investigated, and the solid solubility of Al and Nb atoms in the Ti matrix was quantitatively calculated. The results revealed that the crystallite size of mixed powders without the addition of Al2O3 reinforced particles decreased with the increase of MA time, and was 18 nm after MA for 60 h. The solid solubility values of Al and Nb in the Ti matrix were 22.68 at.% and 9.49 at.%, respectively. The addition of Al2O3 reinforced particles could effectively refine the mixed powder particles, but had no obvious effect on the evolution of particle morphology; the values of load-bearing effects ( Δ σ Load ) and orowan strengthening ( Δ σ Orowan ) were determined to be 27.5 MPa and 88.4 MPa, respectively. The microhardness values of the Ti-22Al-25Nb solid solution powders and Ti2AlNb-5 wt% Al2O3 nanocomposite powders were 435 HV and 465.8 HV, respectively. Compared to Al2O3 reinforced particles, stearic acid process control agent could significantly inhibit the welding between Ti, Al and Nb powders, making the powders more prone to disperse and break into small flakes with a smaller average particle size of 10 µm at 60 h. With the addition of stearic acid, the mechanical alloying process of Ti, Al and Nb element powders was inhibited, and the solid solubility of Al in the Ti matrix and the microhardness of the mixed powders after MA for 60 h were reduced to 16.31 at.% and 330 HV, respectively.

Published
2020

42. Numerical simulation of multi-stage fractured horizontal well in low-permeable oil reservoir with threshold pressure gradient with moving boundary

Author

Liu Wenchao, Qitao Zhang, and Weiyao Zhu

Subjects
Computer simulation, Multiphysics, Flow (psychology), Boundary problem, 02 engineering and technology, Mechanics, 010502 geochemistry & geophysics, Geotechnical Engineering and Engineering Geology, Gravitational acceleration, 01 natural sciences, Petroleum reservoir, Fuel Technology, 020401 chemical engineering, Fluid dynamics, 0204 chemical engineering, Geology, Pressure gradient, 0105 earth and related environmental sciences
Abstract

A stimulation technology of multi-stage fractured horizontal well is commonly used for enhancing the productivity in the development of low-permeable oil reservoirs. However, it is well known that the fluid flow in low-permeable oil reservoirs doesn't obey conventional Darcy's law, and the threshold pressure gradient exists; as a result, in fact, the model of multi-stage fractured horizontal well in low-permeable oil reservoirs belongs to a nonlinear moving boundary problem. And realization of the numerical simulation for the model is very complicated and difficult. It is significant to figure out the threshold pressure gradient effect on the numerical simulation results for the solution of actual engineering problems. In view of the concerns, based on the subsurface Darcy's flow module in COMSOL Multiphysics, an effective numerical simulation method is presented here: The non-Darcy kinematic equation at the full pressure gradient range is expressed at the interface of the gravitational acceleration vector in Darcy's law. Furthermore, the simulation method is strictly verified through the comparison with two analytical solutions for a one-dimensional case and a two-dimensional case (radial flow) respectively. Consequently, according to a constructed model, which can cover non-Darcy flow in the unstimulated reservoir area with threshold pressure gradient, Darcy's flow in the stimulated reservoir area and Darcy's flow in the main hydraulic fractures, the two-dimensional numerical simulation of the multi-stage fractured horizontal well in the low-permeable oil reservoir is realized just through the subsurface Darcy's flow module. Finally, through analyses and discussions on the numerical results for several designed simulation scenarios, some significant conclusions are obtained such as due to the threshold pressure gradient effect, there exists large undeveloped areas in low-permeable oil reservoirs, which don't change with the production time for the constant well production pressure condition; SRV fracturing can largely improve the utilization degree of the low-permeable reservoir area between the adjacent main hydraulic fractures at the early production period; it is very necessary to incorporate the threshold pressure gradient effect in the simulation for the optimal well spacing design in the development of low-permeable oil reservoirs.

Published
2019

43. An exact analytical solution of moving boundary problem of radial fluid flow in an infinite low-permeability reservoir with threshold pressure gradient

Author

Liu Wenchao, Zhangxin Chen, Jun Yao, and Weiyao Zhu

Subjects
Physics, Boundary problem, Boundary (topology), 02 engineering and technology, Mechanics, 010502 geochemistry & geophysics, Geotechnical Engineering and Engineering Geology, 01 natural sciences, Nonlinear system, Fuel Technology, 020401 chemical engineering, Fluid dynamics, Uniqueness, Boundary value problem, 0204 chemical engineering, Pressure gradient, 0105 earth and related environmental sciences, Dimensionless quantity
Abstract

Many engineering technologies involve the moving boundary problems for the radial seepage flow with a threshold pressure gradient, such as the well testing in the development of low-permeability reservoirs, heavy oil reservoirs and groundwater resources. However, as a result of the strong nonlinearity, an exact analytical solution of the moving boundary problems for the radial seepage flow with a threshold pressure gradient has not been obtained yet. Here, a dimensionless moving boundary mathematical model for the radial fluid flow in an infinite low-permeability reservoir with a threshold pressure gradient is developed first. The setting of a variable well production rate for an inner boundary condition can make the mathematical model exhibit a full self-similarity property. Second, by introducing some similarity transformations, the nonlinear system of PDEs of the model can be equivalently transformed into a closed pseudo-linear system of ODEs, whose exact analytical solution can be easily obtained. What's more, the existence and the uniqueness of the exact analytical solution to the moving boundary model are also proved strictly through the mathematical analysis. Third, it is also strictly proved that the exact analytical solution can be degenerated to that of the model of the Darcy's radial fluid flow as the threshold pressure gradient approaches to zero. Finally, by a comparison of model analytical solutions, it is demonstrated that the moving boundary conditions must be incorporated in the modeling of the radial seepage flow with a threshold pressure gradient; otherwise, the effect of the threshold pressure gradient on the radial seepage flow can be overestimated largely.

Published
2019

44. Point spread function generation method of Geo-stationary GNSS based bistatic forward looking SAR

Author

Yongcai Pan, Zeng Zhangfan, Zhou Yanling, Liu Wenchao, Zhiming Shi, and Lan Ting

Subjects
Synthetic aperture radar, Point spread function, Computer science, Transmitter, Real-time computing, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials, 010309 optics, Bistatic radar, GNSS applications, 0103 physical sciences, Electrical and Electronic Engineering, 0210 nano-technology, Point target
Abstract

GNSS based Bistatic Forward Looking Synthetic Aperture Radar (GNSS-BFLSAR) system is particular kind of passive bistatic SAR system. In the system, GNSS is used as the transmitter, while the receiver is mounted on the airplane. The airplane travels along a straight line and the imaging target is in the front. GNSS-BFLSAR is benefited from low cost and good safety. It is widely used in self-landing, self-navigating and battle field information acquiring, etc. This paper is focusing on the investigation of point target 2-D spectrum of GNSS-BFLSAR and Point Spread Function (PSF) generation method. First, a geometric model of such system is built, followed by the generation of echo signal. Then, the analytical formula of 2-D spectrum is obtained. Next, the PSF generation is provided. In the end, the whole procedure is simulated with Matlab. The simulation result verifies the validity of theoretical analysis of this paper and makes a foundation for imaging formation research of such system in the future.

Published
2019

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