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Effect of succinic acid on morphology transformation of the anhydrous magnesium carbonate particles prepared by magnesium chloride hexahydrate and urea

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Particuology 2024年第7期90卷 209-217页

作者： song liu Guojun Cheng Zhongfeng Tang School of Materials Science and Engineering Anhui University of Science and TechnologyHuainan232001China Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China Anhui Province Key Laboratory of Environment-friendly Polymer Materials Anhui UniversityHefei230601China

The homogeneous and controllable morphology of anhydrous magnesium carbonate(MgCO_(3))particles with excellent properties is difficult to obtain because of a variety of synthetic *** effect of succinic acid as a crystal modifier on the particle morphology transformation of anhydrous MgCO_(3)was investigated by the hydrothermal *** effect of the addition of succinic acid on the particles was similar to that of temperature *** morphology of particles with a folded diamond-like shape was gradually uniform,and the particle size was between 3.3 and 7.5μ*** MgCO_(3)particles prepared at pH 9 could easily agglomerate,and the average particle size increased from diamond-like to cube-like as the reaction time *** interaction between succinic acid and magnesium ions at different concentrations was the main factor responsible for the morphological *** pH,temperature,and time affected the molecular motion rate and crystal growth.

关键词： MgCO_(3) MgCl_(2)·6H_(2)O Urea Succinic acid Morphology

Reversible chemical switches of functionalized nitrogen-doped graphene field-effect transistors

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Chinese Chemical Letters 2020年第2期31卷 565-569页

作者： Rong Rong song liu Institute of Chemical Biology and Nanomedicine(ICBN) State Key Laboratory of Chemo/Biosensing and ChemometricsCollege of Chemistry and Chemical EngineeringHunan UniversityChangsha 410082China

Nitrogen doping is a promising way to modulate the electrical properties of graphene to realize graphene-based electronics and promise fascinating properties and ***,we report a method to noncovalently assembly titanium(Ⅳ) bis(ammoniumlactato) dihydroxide(Ti complex) on nitrogen-doped graphene to create a reliable hybrids which can be used as a reversible chemical induced *** the adsorption and desorption of Ti complex in sequential treatments,the conductance of the nitrogen-doped graphene transistors was finely *** experiments with pristine graphene clearly demonstrated the important effort of the nitrogen in this chemical *** optimized conditions,nitrogen-doped graphene transistors open up new ways to develop multifunctional devices with high sensitivity.

关键词： Field-effect transistors Nitrogen-doped graphene Doping effect Ti complex Reversible switch

The Estimates of All Homogeneous Expansions for a Subclass of Biholomorphic Mappings Which Have Parametric Representation in Several Complex Variables

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Acta Mathematica Sinica,English Series 2017年第2期33卷 287-300页

作者： Xiao song liu Tai Shun liu School of Mathematics and Statistics Lingnan Normal University Department of Mathematics Huzhou Teachers College

In this paper, we obtain the estimates of all homogeneous expansions for a subclass of bi- holomorphic mappings which have parametric representation on the unit ball of complex Banach spaces. Meanwhile, we also establish the estimates of all homogeneous expansions for the above generalized mappings on the unit polydisk in Cn. Especially, the above estimates are only sharp for biholomorphic starlike mappings and starlike mappings of order α under restricted conditions. Our derived results generalize many known results.

关键词： Estimate of homogeneous expansion starlike mapping starlike mapping of order α quasi-convex mapping quasi-convex mapping of type A parametric representation

Piecewise linear recursive convolution FDTD method for magnetized plasmas

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Journal of Systems Engineering and Electronics 2006年第2期17卷 290-295页

作者： liu song Zhong Shuangying liu Shaobin School of Sciences Nanchang Univ. Nanchang 330047 P. R. China

The piecewise linear recursive convolution （PLRC） finite-different time-domain （FDTD） method greatly improves accuracy over the original recursive convolution （RC） FDTD approach but retains its speed and efficiency advantages. A PLRC-FDTD formulation for magnetized plasma which incorporates both anisotropy and frequency dispersion at the same time is presented, enabled the transient analysis of magnetized plasma media. The technique is illustrated by numerical simulations the reflection and transmission coefficients through a magnetized plasma layer. The results show that the PLRC-FDTD method has significantly improved the accuracy over the original RC method.

关键词： electromagnetic wave FDTD methods piecewise linear recursive convolution magnetized plasma.

Microstructure, thermophysical property and ablation behavior of high thermal conductivity carbon/carbon composites after heat-treatment

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Chinese Journal of Aeronautics 2020年第5期33卷 1541-1548页

作者： Xue-song liu Qian-Gang FU Hui WANG Qiang song State Key Laboratory of Solidification Processing Shannxi Province Key Laboratory of Fiber Reinforced Light Composite MaterialsNorthwestern Polytechnical UniversityXi'an 710072PR China

Uni-directional carbon/carbon composites with high thermal conductivity are suitable to supply continuous thermal protection for future reentry vehicles since they could reduce surface temperature and ablation rates simultaneously in harsh *** this work,the high thermal conductivity carbon/carbon composites were prepared by chemical vapor *** heat-treatment,both their open porosity and internal friction increase due to the fiber/matrix thermal expansion mismatch;while their thermal conductive performance become better due to more complete carbon *** raising heat-treatment temperature from 1800℃to 2450℃,the mass and linear ablation rates of C/C composites with fibers vertical to the oxyacetylene torch for 60 s decrease from 0.66 mg/s and 2.95μm/s to 0.51 mg/s and 2.05μm/s *** improved ablation resistance is resulted from the increased thermal conductivity from 282 to 508 W/(m·K)and more carbon fibers exposed to the flame during ablation,which have better oxidation resistance than those of carbon *** such ablation rates become larger for composites with fibers parallel to the flame,from 1.02 mg/s and 3.73μm/s to 1.28 mg/s and 5.0μm/s respectively since the ablation occurred more easily through gaps at the fiber/matrix interfaces,which become larger and are always exposed to the flame for this case.

关键词： Ablation Carbon/carbon composites Fiber orientation Heat treatment Thermal conductivity

Preparation of nitrogen-doped titania and its photocatalytic activity

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Rare Metals 2007年第3期26卷 254-262页

作者： QIN Haoli GU Guobang liu song College of Chemistry South China University of Technology Guangzhou 510640 China School of Science Guizhou Normal University Guiyang 550001 China

Yellowish nitrogen-doped titania was produced through sol-gel method in mild condition, with the elemental nitrogen derived from aqua ammonia. The titania catalysts were characterized using XRD, BET, TEM, XPS, and UV-Vis diffuse reflectance spectrophotometer, and their photocatalytic activities were evaluated under UV and visible light, respec tively. The XRD results showed that all titania catalysts were anatase. More significantly, the crystallite size of nitrogen-doped titania increased with an increase in N/Ti proportion, and the doping of nitrogen could extend the absorption shoulder into the visible-light region, thus it possessed a higher visible-light activity illustrated by decolorization of methyl orange （65.3%） under the irradiation of visible light, whereas pure titania showed little of such kind of visible light activity. The UV-light activity of nitrogen-doped titania catalysts was worse than that of pure titania and Degussa P25. In the range of N/Ti proportion of 4-10 mol%, the activity of nitrogen-doped titania weakened appreciably in the visible-light region as the N/Ti proportion increased, whereas a reverse relationship existed under the irradiation of UV light.

关键词： photocatalysts titania nitrogen-doped methyl orange

Experimental study of lightweight aggregate concrete under multiaxial stresses

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2010年第8期11卷 545-554页

作者： Han-yong liu Yu-pu song Structural Engineering Institute School of Civil Engineering Faculty of lnfrastructure Engineering Dalian University of Technology Dalian 116024 China

Lightweight aggregate concrete cube specimens (100 mm×100 mm×100 mm) and plate specimens (100 mm×100 mm×50 mm) were tested under biaxial compression-compression (CC) and compression-tension (CT) load combinations. For comparison, normal concrete plate specimens (100 mm×100 mm×50 mm) were tested under the same load combinations. Based on the test results, a two-level strength criterion of lightweight aggregate concrete in both octahedral stress coordinate and principal stress coordinate was suggested. The lightweight aggregate concrete cube specimens (100 mm×100 mm×100 mm) were then tested under triaxial compression-compression-compression (CCC) load combination with corresponding tests on normal concrete cube specimens (100 mm×100 mm×100 mm). The effect of intermediate principal stress on triaxial compressive strength is further examined. A "plastic flow plateau" area was apparent in principal compressive stress-strain relationships of lightweight aggregate concrete but not in normal concrete. A quadratic formula was suggested for the expression of strength criterion under triaxial compression.

关键词： Lightweight aggregate concrete Normal concrete Biaxial loads Triaxial loads Compressive strength Tensile strength Stress-strain relationships Plastic flow plateau Lode angle

A Generalization of the Mean Size Formula of Wavelet Packets in L_p

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Acta Mathematica Sinica,English Series 2005年第6期21卷 1475-1486页

作者： song LI Guo Mao WANG Zhi song liu Department of Mathematics Zhejiang University Hangzhou 310027 P. R. China

The purpose of this paper is to investigate the mean size formula of wavelet packets in Lp for 0 〈 p ≤ ∞. We generalize a mean size formula of wavelet packets given in terms of the p-norm joint spectral radius and we also give some asymptotic formulas for the Lp-norm or quasi-norm on the subdivision trees. All results will be given in the general setting,

关键词： mean size joint spectral radii wavelet packet subdivision sequence

Transformation of nanoscale inclusions in 316L stainless steel processed by laser beam powder bed fusion during isothermal heating

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Journal of Iron and Steel Research International 2023年第4期30卷 795-807页

作者： Cheng-song liu Wei liu Hua Zhang Hong-wei Ni The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina Hubei Provincial Key Laboratory for New Processes of Ironmaking and Steelmaking Wuhan University of Science and TechnologyWuhan 430081HubeiChina

Transformation mechanisms and reaction kinetics for formation of nanoscale inclusions in as-built 316L stainless steel produced by laser beam powder bed fusion(LB-PBF)during subsequent isothermal heating process were investigated and clarified experimentally and *** resulting changes in morphologies,size distributions,number densities,and chemical compositions of the inclusions were measured and discussed,along with microstructure and texture of the *** results showed that with increasing isothermal heating time and temperature,the columnar grains in the as-built LB-PBF 316L stainless steel transformed into equiaxed grains,which grew gradually and exhibited a large number of twins in the FCC *** isothermal heating,the reaction of Si in the steel with MnO–Cr_(2)O_(3)in the nanoscale inclusion resulted in a transformation from the homogeneous oxide MnO–SiO_(2)–Cr_(2)O_(3)to an inclusion with an obvious core–shell structure,and the core part was eventually rich in Si and the shell part was predominantly rich in Mn and Si,depending on the heating temperature and *** Ostwald ripening model used for predicting the growth of nanoscale inclusions during isothermal heating verified that the observed effects of isothermal heating time and temperature were predicted for Si diffusion control.

关键词： 316L stainless steel Laser beam powder bed fusion Nanoscale inclusion Isothermal heating Transformation