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Altering the Hierarchical Morphology Distribution of Injection Molded Polyethylene by the Introduction of Crosslink Network and Periodical Shear

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Chinese Journal of Polymer Science 2016年第12期34卷 1479-1489页

作者： zhi-hao zhao Fei-fei Wang Man Zhou Kai-zhi Shen 张杰 College of Polymer Science and Engineer'ing State Key Laboratory of Polymer Materials En~neeringSichuan UniversityChengdu 610065China

High density polyethylene （HDPE） with moderate content of crosslink network （CPE） was successfully prepared through chemical method. Specimens for structural characterization have been molded by conventional injection molding （CIM） and pressure vibration injection molding （PVIM）. Influence of crosslink network on hierarchical morphology distribution and mechanical properties was systematically studied. Polarized light microscopy （PLM） revealed that both CIM and PVIM PE samples have a typical ＂skin-core＂ structure and the thickness of shear layer of CIM PE and PVIM CPE samples obviously increase. Scanning electron microscopy （SEM） showed that shish-kebab structures are clearly observed in shear layer of CIM CPE sample, indicating that the crosslink network can surely improve the formation of shish-kebab structures. Moreover, we suppose that shish-kebab structures emerged in shear and core layer of PVIM CPE sample. Wide- angle X-ray diffraction （WAXD） and small-angle X-ray scattering （SAXS） confirmed that more orientation and shish-kebab structures form even in core layer of PVIM CPE sample, which demonstrated that the hierarchical morphology was apparently altered by periodical shear and crosslink network. Finally, the mechanical properties revealed that this oriented structure increase the tensile strength from 31 MPa of CIM PE sample to 46 MPa of PVIM CPE sample. However, the tensile behavior tended to change from ductile fracture to brittle fracture.

关键词： Shish-kebab Morphology distribution Periodical shear Mechanical properties.

Electron Transport through Hydrogen Bonded Single-Molecule Junctions

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Chinese Journal of Chemistry 2023年第23期41卷 3433-3446页

作者： Jiu-Hong Fang zhi-hao zhao Ang-Xuan Li Lin Wang Engineering Research Center of Ministry of Education for Geological Carbon Storage and Low Carbon Utilization of Resources Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid WastesNational Laboratory of Mineral MaterialsSchool of Materials Science and TechnologyChina University of Geosciences (Beijing)Beijing100083 China State Key Laboratory of Solidification Processing and School of Materials Science and Engineering Northwestern Polytechnical UniversityXi'anShaanxi710072 China

Hydrogen bonding is a vital driving force for organizing the hierarchy of molecular structure,especially in biologic *** to its directionality,selectivity and moderate strength,hydrogen bonding has been extensively introduced into the molecular recognition,sensing and electronic *** measurements at single-molecule level facilitate the investigation of hydrogen bonds and provide a comprehensive understanding of the electron transport properties governed by the hydrogen bonding,which is essential for the development of self-assembled electronic *** review provides a detailed overview of recent advancements in constructing single-molecule junctions utilizing intramolecular and intermolecular hydrogen *** first introduce the methods utilized for characterizing the electric and dynamic properties of non-covalent ***,we discuss the mechanisms of electron transport,relevant influencing factors,and typical applications utilizing electrical signals based on single-molecule ***,we propose our perspective on the existing challenges and prospective opportunities in utilizing hydrogen bonding for electronic device applications.

关键词： Electron transport Hydrogen bond Single-molecule junction Molecular devices Molecular assembly

Microstructure and mechanical properties of the welding joint filled with microalloying 5183 aluminum welding wires

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International Journal of Minerals,Metallurgy and Materials 2014年第6期21卷 577-582页

作者： Zhen Xu zhi-hao zhao Gao-song Wang Chao Zhang Jian-zhong Cui The Key Laboratory of the Ministry of Education of China for Electromagnetic Processing of Materials Northeastern University

In this study, 7A52 aluminum alloy sheets of 4 mm in thickness were welded by tungsten inert gas welding using microalloying welding wires containing traces of Zr and Er. The influence of rare earth elements Zr and Er on the microstructure and mechanical properties of the welded joints was analyzed by optical microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, hardness testing, and tensile mechanical properties testing. Systematic analyses indicate that the addition of trace amounts of Er and Zr leads to the formation of fine Al3Er, Al3Zr, and Al3（Zr,Er） phases that favor significant grain refinement in the weld zone. Besides, the tensile strength and hardness of the welded joints were obviously improved with the addition of Er and Zr, as evidenced by the increase in tensile strength and elongation by 40 MPa and 1.4%, respectively, and by the welding coefficient of 73%.

关键词： aluminum alloys inert gas welding rare earth elements microalloying joints microstructure mechanical properties

As-cast structure of DC casting 7075 aluminum alloy obtained under dual-frequency electromagnetic field

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International Journal of Minerals,Metallurgy and Materials 2014年第2期21卷 150-154页

作者： zhi-hao zhao Zhen Xu Gao-song Wang Qing-feng Zhu Jian-zhong Cui The Key Laboratory of the Ministry of Education of China for Electromagnetic Processing of Materials Northeastern University

We have experimentally determined the as-cast structures of semi-continuous casting 7075 aluminum alloy obtained in the pres-ence of dual-frequency electromagnetic field. Results suggest that the use of dual-frequency electromagnetic field during the semi-continuous casting process of 7075 aluminum alloy ingots reduces the thickness of the surface segregation layer, increases the height of the melt menis-cus, enhances the surface quality of the ingot, and changes the surface morphology of the melt pool. Moreover, low-frequency electromag-netic field was found to show the most obvious influence on improving the as-cast structure because of its high permeability in conductors.

关键词： electromagnetic fields: semi-continuous casting aluminum alloys as-cast structure

Effects of low-frequency electromagnetic field on the surface quality of 7050 aluminum alloy ingots during the hot-top casting process

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International Journal of Minerals,Metallurgy and Materials 2011年第2期18卷 165-168页

作者： Xiang-jie Wang Jian-zhong Cui Yu-bo Zuo zhi-hao zhao Hai-tao Zhang Key Lab of Electromagnetic Processing of Materials （Ministry of Education） Northeastern University Shenyang 110004 China

To improve the quality of 7050 aluminum alloy ingots, low-frequency electromagnetic （LFE） field was applied during the conventional hot-top casting process. Macrostructures and microstructures of the ingots by the conventional and LFE hot-top casting processes were studied. The experimental results show that when the LFE field is turn off during the hot-top casting process, cold folding appears, and the as-cast structure becomes very coarse. Additionally, the thickness of the shell zone is much thinner during the low-frequency electromagnetic hot-top casting process than that during the conventional hot-top casting process. Some reasons for low-frequency electromagnetic field improving the surface quality, refining the structure of the ingot, and minimizing the thickness of the shell zone have been studied.

关键词： aluminum alloys solidification surface quality electromagnetic field

Large electro-strain signal of the BNT-BT-KNN lead-free piezoelectric ceramics with CuO doping

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Journal of Advanced Dielectrics 2019年第3期9卷 12-18页

作者： zhi-hao zhao Rui-Fang Ge Yejing Dai School of Materials Sun Yat-sen University Guangzhou 510275P.R.China Key Laboratory for Advanced Ceramics and Machining Technology of Ministry of Education School of Materials Science and Engineering Tianjin University Tianjin 300072P.R.China

This paper investigates a system of 0.93Bi_(0.5)Na_(0.5)TiO_(3)–0.06BaTiO_(3)–0.01K_(0.5)Na_(0.5)NbO_(3)–xCuO(BNT–BT–KNN–xCuO,x=0-0:04 mol.%)ceramics,which were fabricated by the conventional solid-state process through the granulation of vacuum freeze *** results show that the CuO doping made a significant enhancement on the piezoelectric properties of the BNT–BT–KNN *** the doping of CuO,the transition temperature between ferroelectric phase and ergodic relaxor state is reduced to near room temperature,resulting in pinched P–E loops and“sprout”shape S-E *** the composition with x=0.01,a high unipolar strain of 0.39%under 5 kV/mm contributes a large d^(*)33~780 pm/V at room temperature,which is competitive with the other BNT-based ceramics.

关键词： Lead-free piezoelectric ceramics BNT-based CuO dopant electro-strain

Synergistic anticancer properties of docosahexaenoic acid and 5-fluorouracil through interference with energy metabolism and cell cycle arrest in human gastric cancer cell line AGS cells

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World Journal of Gastroenterology 2016年第10期22卷 2971-2980页

作者： Kun Gao Qi Liang zhi-hao zhao You-Fen Li Shu-Feng Wang The Key Laboratory of Biomedical Information Engineering of Ministry of Education School of Life Science and Technology Xi'an Jiaotong University Xi'an 710049 Shaanxi Province China Department of Anesthesiology Xi'an Traditional Chinese Medicine Hospital Xi'an 710021 Shaanxi Province China Department of General Surgery The First Affiliated Hospital of Xi'an Jiaotong University Xi'an 710061 Shaanxi Province China

AIM: To explore the synergistic effect of docosahexaenoic acid(DHA)/5-fluorouracil(5-FU) on the human gastric cancer cell line AGS and examine the underlying ***: AGS cells were cultured and treated with a series of concentrations of DHA and 5-FU alone or in combination for 24 and 48 h. To investigate the synergistic effect of DHA and 5-FU on AGS cells, the inhibition of cell proliferation was determined by MTT assay and cell morphology. Flow cytometric analysis was also used to assess cell cycle distribution, and the expression of mitochondrial electron transfer chain complexes(METCs)?Ⅰ, Ⅱ and Ⅴ in AGS cells was further determined by Western blot analysis. RESULTS: DHA and 5-FU alone or in combination could markedly suppress the proliferation of AGS cells in a significant time and dose-dependent manner. DHA markedly strengthened the antiproliferative effect of 5-FU, decreasing the IC50 by 3.56-2.15-fold in an apparent synergy. The morphological changes of the cells were characterized by shrinkage, cell membrane blebbing and decreased adherence. Cell cycle analysis showed a shift of cells into the G0/G1 phase from the S phase following treatment with DHA or 5-FU(G0/G1 phase: 30.04% ± 1.54% vs 49.05% ± 6.41% and 63.39% ± 6.83%, respectively, P < 0.05; S phase: 56.76% ± 3.14% vs 34.75% ± 2.35% and 25.63% ± 2.21%, respectively, P < 0.05). Combination treatment of DHA and 5-FU resulted in a significantly larger shift toward the G0/G1 phase and subsequent reduction in S phase(G0/G1 phase: 69.06% ± 2.63% vs 49.05% ± 6.41% and 63.39% ± 6.83%, respectively, P < 0.05; S phase: 19.80% ± 4.30% vs 34.75% ± 2.35% and 25.63% ± 2.21%, respectively, P < 0.05). This synergy was also reflected in the significant downregulation of the expression of METCs in AGS ***: Synergistic anticancer properties of DHA and 5-FU may involve interference with energy production of AGS cells via downregulation of METCs and cell cycle arrest.

关键词： Docosahexaenoic acid Gastric cancer 5-fluorouracil Cell line Mitochondria

Structures and macrosegregation of a 2024 aluminum alloy fabricated by direct chill casting with double cooling field

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China Foundry 2022年第1期19卷 1-8页

作者： Cheng Zhu zhi-hao zhao Qing-feng Zhu Gao-song Wang Yu-bo Zuo Gao-wu Qin Research Center for Metallic Wires School of Materials Science and EngineeringNortheastern UniversityShenyang 110819China Key Laboratory of Electromagnetic Processing of Materials Ministry of EducationNortheastern UniversityShenyang 110819China Key Laboratory of Anisotropy and Texture of Materials Ministry of EducationNortheastern UniversityShenyang 110819China

Central region coarse grains and centerline segregation are common defects in aluminum ingots fabricated by direct chill(DC)casting.A double cooling field was introduced into the DC casting process to reduce these defects,whereby the external cooling was supplied by the mold and water jets,and intercooling was achieved by inserting a rod of the same alloy into the molten pool along the central axis of the *** than forming a good metallurgical interface during solid-liquid compound casting,in the present work,the purpose of inserting the rod is to enforce internal cooling and consequently decrease the sump ***,the insertion provides more nucleation sites with the unmoltenα-Al *** structure and the macrosegregation of 2024 Al alloy ingots prepared by DC casting with and without the inserts were *** show that when the inserting position is 50 mm above the upper edge of the graphite ring,significant grain refinement in the central region of the ingot and a reduced centerline segregation are achieved.

关键词： aluminum alloy direct chill casting double cooling field grain refinement macrosegregation

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

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Acta Metallurgica Sinica(English Letters) 2015年第6期28卷 725-732页

作者： Lei Li Bo Xu Wei-Ping Tong Hui Zhang Chun-Yan Ban Li-Zi He zhi-hao zhao Yu-Bo Zuo Qing-Feng Zhu Jian-Zhong Cui Key Laboratory of Electromagnetic Processing of Materials Ministry of Education Northeastern University School of Metallurgy and Energy Hebei United University

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid （Pb）/ liquid （Sn） diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field （〈0.3 T）. When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level （0.8-5 T）, the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.

关键词： Microstructural evolution Crystallization behavior Dendrite growth Diffusion behavior Magnetic field Solidification pattern