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WAVE BOTTOM LAYERS DYNAMIC WITH SUSPENDED SEDIMENT OVER VORTEX RIPPLES

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Journal of Hydrodynamics 2004年第2期16卷 201-208页

作者： JIANGChang-bo BAIYu-chuan zhaoZi-dan ZHANGHong-wu CollegeofRiverandOceanengineeringchangshauniversityofScienceandtechnology Changsha410076China instituteofSedimentonRiverandCoastengineering TianjinUniversityTianjin300072China SchoolofCivilengineering TsinghuaUniversityBeijing100084China

Vortex ripple is widely formed in the coastal region, and the dynamic ofvortex is quite important because it is responsible for sediment transport. The flow structurearound the vortex ripples can be modeled as 2D flow due to the geometry of the flow boundaries. Inthis paper, 2D Large-Eddy-Simulation (LES) method was used to predict the flow structure and thedynamic of vortex in the bottom layers under the action of the wave, the numerical simulationresults show a completely process of vortex formation, evolvement and disappearance. Based on thestudy of flow structure, the suspended sediment transport was modeled in present paper. Thesimulated sediment concentrations were compared to measurements from the literature. The agreementbetween the time averaged simulated concentration profiles and measurements is satisfactory. For ahigh setting velocity, the suspended sediment is confined to the vicinity of the bed, and it isdominated by the local bottom shear stress. For a small setting velocity, the suspension is moredominated by the characteristic of vortex. There are two suspended sediment transport peaks observedin the cross-section at the trough and crest in the half period, the second peak is due to theseparation bubble taking the sediment.

关键词： wave boundary layer vortex ripple suspended sediment numerical model

SYNTHESIS AND OPTICAL PROPERTIES OF A NOVEL ORGANIC/INORGANIC HYBRID NONLINEAR OPTICAL POLYMER VIA SOL-GEL PROCESS

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Chinese Journal of Polymer Science 2001年第4期19卷 421-427页

作者： Hong-xia Xi Zhong Li zhao-xi Liang The institute of Chemical engineering South china university Guangzhou 510640 china The institute of Polymer Science, Zhongshan university Guangzhou 510275, china 华南理工大学广东广州中山大学广东广州

A new organic/inorganic hybrid nonlinear optical (NLO) material was developed by the sol-gel process of an alkoxysilane dye with tetraethoxysilane. A NLO moiety based on 4-nitro-4 ' -hydroxy azobenzene was covalently bonded to the triethoxysilane derivative, i.e, gamma -isocyanatopropyl triethoxysilane. The preparation process and properties of the sol-gel derived NLO polymer were studied and characterized by SEM, FTIR,H-1-NMR, UV-Vis, DSC and second harmonic generation (SHG) measurement. The results indicated that the chemical bonding of the chromophores to the inorganic SiO2 networks induces low dipole alignment relaxation and preferable orientational stability. The SHG measurements also showed that the bonded polymer film containing 75 wt% of the akoxysilane dye has a high electro-optic coefficient (r(33)) of 7.1 pm/V at 1.1 mum wavelength, and exhibit good SHG stability, the r(33) values can maintain about 92.7% of its initial value at room temperature for 90 days, and can maintain about 59.3% at 100 degreesC for 300 min.

关键词： sol-gel process nonlinear optical material alkoxysilane dye dipole alignment relaxation chromophore

One dimensional CeO_(2) nanorods/poly(ethylene oxide) solid composite electrolyte for all-solid-state lithium-ion batteries

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Journal of Rare Earths 2024年第3期42卷 570-577,I0005页

作者： Yudi Guo Erqing zhao Xiaofang zhao Shuailei Liu School of Chemistry and Materials engineering Xinxiang UniversityXinxiang453003China School of Chemistry and Chemical engineering Henan Institute of Science and TechnologyXinxiang453003China

The research of poly(ethylene oxide)(PEO)-based solid composite electrolyte with high ionic conductivity and excellent interfacial stability is the key to the development of all-solid-state lithium-ion batteries(ASSLIBs). Herein, uniform nanorod structured CeO_(2) fillers were controllably synthesized by electrospinning, which were subsequently filled into PEO polymer to prepare CeO_(2)/PEO solid composite electrolyte. The addition of CeO_(2) nanorods can reduce both the glass transition temperature and the melting point of PEO polymer, and also interact with PEO and lithium bis(trifluoromethanesulphonyl)imide(LITFSI) by Lewis acid—base reaction. Therefore, the solid composite electrolyte exhibits a high ionic conductivity of 4.52 × 10^(-4)S/cm, a wide electrochemical stability window of about 4.8 V, and a good interfacial stability with Li at 55℃. Moreover, the LiFePO_4/Li ASSLIB divulges the discharging specific capacity of 165, 162, 156 and 146 mA,h/g at 0.2, 0.5, 1 and 2 C, respectively, and achieves the capacity retention of 90.3% after 150 cycles at 0.5 C. Consequently, one dimensional CeO_(2) nanorods can be considered as an alternative filler for polymeric solid electrolyte.

关键词： Poly(ethylene oxide) Solid composite electrolyte CeO_(2)nanorods Ionic conductivity Rare earths

SURFACE MODIFICATION OF CaCO_3 WITH DENDRITIC CARBOXYLIC ACIDS

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Chinese Journal of Polymer Science 2002年第3期20卷 231-235页

作者： zhao-xia Guo Jian Yu institute of Polymer Science and engineering Department of Chemical engineering Tsinghua university Beijing 100084 china institute of Polymer Science and engineering Department of Chemical Engineering Tsinghua University 北京 100084

Nanometer calcium carbonate was modified with Frechet type polyether dendrons bearing a COOH group at thefocal point by a wet-coating technique in dichloromethane at room temperature. The interaction between CaCO;and thedendritic modifier was proven by IR and mass spectroscopy of the modified CaCO;after thorough extraction withdichloromethane. The amount of tightly bonded organic modifier was estimated by TGA. It was shown that the amount ofbonded molecules decreased with increasing generation number due to the larger number of branches. Compared tounmodified CaCO;, the modified CaCO;possess different dispersibility in water and in organic solvents.

关键词： calcium carbonate surface modification polyether dendrimer dendritic carboxylic acid

First photometric study of the eclipsing binary PS Persei

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Research in Astronomy and Astrophysics 2011年第2期11卷 191-197页

作者： Jin-zhao Yuan Physics and Information engineering institute,Shanxi Normal university,Linfen 041004,china Physics and Information engineering institute Shanxi Normal University Linfen 041004 China

CCD photometric observations of the eclipsing binary PS Persei （PS Per） were obtained on two consecutive days in *** 2003 version of the WilsonDevinney code was used to analyze the first complete light curves in the V and R *** is found that PS Per is a short-period Algol-type binary with the less massive component completely filling its inner critical Roche *** mass ratio of q=0.518 and the orbital inclination of i=89.86° are *** addition,based on all available times of primary light minima,including two new ones,the orbital period has been improved.

关键词： stars: binaries: close -- stars: binaries: eclipsing -- stars: individual:PS Per

Fluorescence Associated with Impurities in Nanostructured Al_2O_3

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Journal of Materials Science & technology 1996年第1期12卷 19-24页

作者： Lide ZHANGt and GuoZhong WANG(institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, china)Chimei MO(Dept. of Materials Science and engineering, university of Science and technology of china, Hefei 230026, china)Tienan zhao(institute institute of Solid State Physics Chinese Academy of Sciences Hefei 230031 China Dept. of Materials Science and engineering University of Science and Technology of China Hefei 230026 China institute of Physics Chinese Academy of Sciences Beijing 100080 China

The fluorescent spectra of nanostructured Al2O3 after heat-treating at different temperatureshave been systematically investigated. The results show that for η-Al2O3 and γ-Al2O3, two broadfluorescent bands P1 and P2 appear in the wavenumber range of 20000 cm-1 to 11500 cm-1,and P1 and P2 bands are located in the wavenumber range of 20000 cm-1 to 14500 cm-1 and14500 cm-1 to 11500 cm-1, respectively The P1 band can be attributed to the impurity Cr3+luminescence. This is consistent with other author's result for the Cr doped Al2O3. The P2band is a new fluorescent phenomenon, which has not been reported previously. In this paper,the condition of the appearance of P2 and its mechanism is discussed in detail.

关键词： Al Cr der OO Fluorescence Associated with Impurities in Nanostructured Al2O3

Large eddy simulation of fuel injection and mixing process in a diesel engine

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Acta Mechanica Sinica 2011年第4期27卷 519-530页

作者： Lei Zhou.Mao-zhao Xie.Ming Jia.Jun-Rui Shi School of Energy and Power engineering,Dalian university of technology,116024 Dalian,china Department of Power engineering,Shenyang institute of engineering,110136 Shenyang,china School of Energy and Power engineering Dalian University of Technology Dalian China Department of Power engineering Shenyang Institute of Engineering Shenyang China

The large eddy simulation （LES） approach implemented in the KIVA-3V code and based on one-equation sub-grid turbulent kinetic energy model are employed for numerical computation of diesel sprays in a constant volume vessel and in a Caterpillar 3400 series diesel engine. Computational results are compared with those obtained by an RANS （RNG k-e） model as well as with experimental data. The sensitivity of the LES results to mesh resolution is also discussed. The results show that LES generally provides flow and spray characteristics in better agreement with experimental data than RANS; and that small-scale random vortical structures of the in-cylinder turbulent spray field can be captured by LES. Furthermore, the penetrations of fuel droplets and vapors calculated by LES are larger than the RANS result, and the sub-grid turbulent kinetic energy and sub-grid turbulent viscosity provided by the LES model are evidently less than those calculated by the RANS model. Finally, it is found that the initial swirl significantly affects the spray penetration and the distribution of fuel vapor within the combustion chamber.

关键词： Large eddy simulation Diesel engine Fuelspray

Transforming liquid flow fuel cells to controllable reactors for highlyefficient oxidation of 5-hydroxymethylfurfural to 2, 5-furandicarboxylic acid at low temperature

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Journal of Energy Chemistry 2024年第3期90卷 621-631,I0014页

作者： Ye Qiang Xi Liu Denghao Ouyang zhao Jiang Xuebing zhao Key Laboratory of Industrial Biocatalysis Ministry of EducationTsinghua UniversityBeijing 100084China institute of Applied Chemistry Department of Chemical EngineeringTsinghua UniversityBeijing 100084China School of Chemical engineering and technology Xi'an Jiaotong UniversityXi'an 710049ShaanxiChina

Highly-efficient oxidation of 5-hydroxymethylfurtural(HMF) to 2,5-furandicarboxylic acid(FDCA) at low temperature with air as the oxidant is still ***,inspired by the respirato ry electron transport chain(ETC) of living cells mediated by electron carriers,we constructed artificial ETCs and transformed liquid flow fuel cells(LFFCs) to flexible reactors for efficient oxidation of HMF to produce FDCA under mild *** LFFC reactor employed an electrodeposition modified nickel foam as an anode to promote HMF oxidation and(VO_(2))_(2)SO_(4) as a cathode electron carrier to facilitate the electron transfer to *** reaction rate could be easily controlled by selecting the anode catalyst,adjusting the external loading and changing the cathodic electron carrier or oxidants.A maximal power density of 44.9 mW cm^(-2) at room temperature was achieved,while for FDCA production,short-circuit condition was preferred to achieve quick transfer of *** a single batch operation with 0.1 M initial HMF,FDCA yield reached 97.1%.By fed-batch operation,FDCA concentration reached 144.5 g L^(-1) with a total yield of 96%.Ni^(2+)/Ni^(3+) redox couple was the active species mediating the electron transfer,while both experimental and DFT calculation results indicated that HMFCA pathway was the preferred reaction mechanism.

关键词： 5-Hydroxymethylfurfural 2 5-Furandicarboxylic acid Electrodeposition Electron transport chain Liquid flow fuel cell

Cortical Organoid-on-a-Chip with Physiological Hypoxia for Investigating Tanshinone IIA-Induced Neural Differentiation

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Research 2024年第3期2023卷 457-468页

作者： Yue Zhi Yujuan Zhu Jinglin Wang Junqi zhao Yuanjin zhao Department of Rheumatology and Immunology Nanjing Drum Tower HospitalClinical Medical College of Traditional Chinese and Western MedicineNanjing University of Chinese MedicineNanjing210023China State Key Laboratory of Bioelectronics School of Biological Science and Medical EngineeringSoutheast UniversityNanjing210096China Shenzhen Research institute Southeast UniversityShenzhen518038China

Cortical organoids represent cutting-edge models for mimic human brain development during the early and even middle stage of pregnancy, while they often fail to recreate the complex microenvironmental factors, such as physiological hypoxia. Herein, to recapitulate fetal brain development, we propose a novel cortical organoid-on-a-chip with physiological hypoxia and further explore the effects of tanshinone IIA (Tan IIA) in neural differentiation. The microfluidic chip was designed with a micropillar array for the controlled and efficient generation of cortical organoids. With low oxygen, the generated cortical organoids could recapitulate key aspects of early-gestational human brain development. Compared to organoids in normoxic culturing condition, the promoted neurogenesis, synaptogenesis and neuronal maturation were observed in the present microsystem, suggesting the significance of physiological hypoxia in cortical development. Based on this model, we have found that Chinese herbal drug Tan IIA could promote neural differentiation and maturation, indicating its potential therapeutic effects on neurodevelopmental disorders as well as congenital neuropsychiatric diseases. These results indicate that the proposed biomimetic cortical organoid-on-a-chip model with physiological hypoxia can offer a promising platform to simulate prenatal environment, explore brain development, and screen natural neuroactive components.

关键词： promoted herbal cutting