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Optical and fast nondestructive identification of the ages of leaded ancient pottery

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Chinese Physics B 2012年第5期21卷 641-646页

作者：吴方媛杨湘波 MOE Key Laboratory of Laser Life science&institute of Laser Life science College of BiophotonicsSouth China Normal University School of Physical Education&sports science South China Normal University

In this paper,based on the one-dimensional（1D） optical superlattice model,we calculate the average reflectivities（ARs） of leaded ancient pottery（AP） made within the last 2000 years,and find that for incident light with a suitable wavelength,the AR of the leaded AP increases monotonously with the increase in the layer number of the silvery glaze（SG） *** on this property,we propose an optical nondestructive method for identifying the age of leaded AP by detecting the *** using the exhaust algorithm and the discriminant function of variance,we obtain the optimal wavelength range of the incident light to identify the ages of the leaded *** is found that in the visible light band,if we choose green light with a wavelength range of 540-540.1 nm as the incident light,leaded AP made within the last 2000 years can be identified swiftly and precisely by detecting the *** will be useful for designing optical instruments for the fast nondestructive identification of the ages of leaded AP.

关键词： optical superlattice ancient pottery nondestructive identification

Computational fluid dynamic simulation of an inter-phasing pulse tube cooler

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Journal of Zhejiang University-science A(Applied Physics & Engineering) 2008年第1期9卷 93-98页

作者： Xiao-bin ZHANG Zhi-hua GAN Li-min QIU Hua-xiang LIU institute of Refrigeration and Cryogenics Zhejiang University Hangzhou 310027 China College of science Guangdong Ocean University Zhanjiang 524088 China

An inter-phasing pulse tube cooler (IPPTC) consists of two pulse tube units, which are connected to each other at hot ends of the pulse tubes through a needle valve. This paper presents the computational fluid dynamic (CFD) results of an IPPTC using a 2D axis-symmetrical model. General results such as the phase difference between pressure and velocity at cold end and hot end, the temperature profiles along the wall, the available lowest temperature as well as its oscillations and the coefficient of performance (COP) for IPPTC are presented. The formation of DC flow and its effects on the performance of the cooler are investigated and analyzed in detail. Turbulence, which is partially responsible for the poor overall performance of a single orifice pulse tube cooler (OPTC), is found to be much reduced in IPPTC and its performance is improved significantly compared with the single OPTC.

关键词： Inner-phasing Pulse tube cooler (PTC) Computational fluid dynamic (CFD)

Soft-Magnetic High-Entropy AlCoFeMnNi Alloys with Dual-Phase Microstructures Induced by Annealing

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Acta Metallurgica Sinica(English Letters) 2020年第8期33卷 1124-1134页

作者： Chengbo Yang Jing Zhang Meng Li Xuejian Liu College of Materials science and Engineering Chongqing UniversityChongqing 400044China guangdong institute of Materials and Processing Guangzhou 510650China

The simultaneous enhancement of magnetic and mechanical properties is desirable but challenging for soft-magnetic materials.A fabrication strategy to meet this requirement is therefore in high ***,bulk equiatomic dual-phase AlCoFeMnNi high-entropy alloys were fabricated via a magnetic levitation induction melting and casting process followed by annealing at 700-1000℃,and their microstructures as well as mechanical and magnetic properties were *** as-cast alloy possessed a single metastable B2-ordered solid solution that decomposed upon annealing into a dual-phase structure comprising an Al-and Ni-rich body-centered cubic(BCC)matrix and Fe-and Mn-rich face-centered cubic(FCC)precipitates both in the grain interior and along the grain *** magnetic and mechanical properties were closely related to the relative volume fraction of FCC in the *** FCC volume fraction could be increased by increasing the annealing temperature,thereby offering tunable *** optimal annealing temperature for balanced magnetic and mechanical properties was found to be 800℃.The alloy annealed at this temperature had an average BCC grain size of 12±3μm and FCC volume fraction of 41±4%.Correspondingly,the s aturation magnetization and coercivity reached 82.57 Am^2/kg and 433 A/m,*** compressive yield strength and fracture strength were 1022 and 2539 MPa,respectively,and the plasticity was 33%.Owing to its adjustable microstructure and properties,the AlCoFeMnNi alloy has potential for use as a multi-functional soft-magnetic material.

关键词： High-entropy alloy Microstructure Phase transformation Soft-magnetic material Precipitation

Microscopic study on the key process and influence of efficient synthesis of natural gas hydrate by in situ Raman analysis of water microstructure in different systems with temperature drop

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Journal of Energy Chemistry 2023年第7期82卷 317-333,I0008页

作者： Wei Zhang Chun-Gang Xu Xiao-Sen Li Zhuo-Yi Huang Zhao-Yang Chen School of Engineering science University of Science and Technology of ChinaHefei 230023AnhuiChina Guangzhou institute of Energy Conversion Chinese Academy of SciencesGuangzhou 510640GuangdongChina CAS Key Laboratory of Gas Hydrate Guangzhou 510640GuangdongChina guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development Guangzhou 510640GuangdongChina School of Energy science and Engineering University of Science and Technology of ChinaHefei 230023AnhuiChina

Gas hydrate technology has considerable potential in many ***,due to the lack of understanding of the micro mechanism of hydrate formation,it has not been commercially applied so *** hydrate formation is essentially a gas-liquid-solid phase transition of water and gas molecules at a certain temperature and *** key to the hydrate formation is the transformation of water molecule from disordered arrangement to ordered *** this process,weakly hydrogen bonded water will be correspondingly converted to strongly hydrogen bonded *** in situ Raman analysis and experiments,the position change of the corresponding peaks of the strongly hydrogen bonded water and the weakly hydrogen bonded water was compared in this work,and the key microscopic process and influence of gas hydrate formation in different systems were comprehensively studied and *** is found that,with the decrease of temperature,the OAH of the weakly hydrogen bonded water remains unchanged when the temperature drops to a certain value,which is the key to the transformation of water into cage hydrate rather than *** conversion from the weakly hydrogen bonded water to the strongly hydrogen bonded water is closely related to the gas-liquid interface force,the hydrophilicity/hydrophobicity of the promoter,the ionization degree of liquid,and the electrostatic field of the *** the four most common promoters,tetrahydrofuran(THF)has the highest efficiency in promoting methane(CH4)hydrate ***,this study provides a scientific direction and basis for the development of high efficient hydrate formation promoters,which can effectively weaken the hydrogen bond of weakly hydrogen bonded water and promote the conversion of weakly hydrogen bonded water to strongly hydrogen bonded water.

关键词： Hydrate Conversion Hydrogen bonded water Promoter Micro mechanism

Purification and molecular weight distribution of a key exopolysaccharide component of Bacillus megaterium TF10

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Journal of Environmental sciences 2018年第1期30卷 9-15页

作者： Lingling Wang Longfei Wang Qingshan Shi Hanqing Yu State Key Laboratory of Applied Microbiology Southern China Guangdong Provincial Key Laboratory of Microbial Culture Collection and ApplicationGuangdong Institute of Microbiology Department of Chemistry University of Science & Technology of China

Extracellular polymeric substances（EPS） are organic metabolic compounds excreted by microorganisms. They largely impact microbial aggregate structures and *** polysaccharides（EP） in EPS are responsible for the formation of microbial aggregates. In this work, we successfully separated and characterized EP from EPS of the bacterium Bacillus megaterium TF10. Extraction of EP from EPS was optimized using Sevag＇s reagent. Chemical characteristics, functional groups, and molecular weight（MW） distribution of EP were compared with the harvested EPS and soluble microbial products（SMP）. We found that the polymers of lower MW and free proteins were successfully removed by Sevag＇s reagent. The higher MW components of EPS were predominantly polysaccharides,while the polymers of lower MW tended to secrete to the supernatant and were described as SMP. A part of the proteins in the EP was polysaccharide-bonded. Our results can be further used in elucidating the complex flocculation mechanisms in which EP play a major role.

关键词： Extracellular polysaccharides(EP) Extracellular polymeric substances(EPS) Soluble microbial products(SMP) Molecular weight(MW) distribution

DRBin:metagenomic binning based on deep representation learning

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Journal of Genetics and Genomics 2022年第7期49卷 681-684页

作者： Gang Mao Yulin Wu Yang Zhang Xuan Wang Yan Zhu Bo Liu Yadong Wang Junyi Li School of Computer science and Technology Harbin Institute of Technology(Shenzhen)ShenzhenGuangdong 518055China College of science Harbin Institute of Technology(Shenzhen)ShenzhenGuangdong 518055China Technology(Shenzhen) ShenzhenGuangdong 518055China Center for Bioinformatics School of Computer Science and TechnologyHarbin Institute of TechnologyHarbinHeilongjiang 150001China

Metagenomic binning is the process of sorting genome or contig sequences obtained by metagenomic sequencing of environmental DNA or genetically heterogeneous groups of organisms into categories representing the individual species or genetically homogenous groups (e.g., strains) from which they originated (Rasheed and Rangwala, 2013). Conventionally, whole-genome sequencing of single species requires culture and isolation of microorganisms.

关键词： originated representing sorting

A multiscale Galerkin method for the hypersingular integral equation reduced by the harmonic equation

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Applied Mathematics(A Journal of Chinese Universities) 2013年第1期28卷 75-89页

作者： LI Song-hua XIAN Jun Department of Mathematics Hunan institute of science and technology Department of Mathematics and guangdong Province Key Laboratory of Computational science Sun Yat-sen University

The aim of this paper is to investigate the numerical solution of the hypersingular integral equation reduced by the harmonic equation. First, we transform the hypersingular integral equation into 2π-periodic hypersingular integral equation with the map x=cot（θ/2）. Second, we initiate the study of the multiscale Galerkin method for the 2π-periodic hypersingular integral equation. The trigonometric wavelets are used as trial functions. Consequently, the 2j＋1 × 2j＋1 stiffness matrix Kj can be partitioned j×j block matrices. Furthermore, these block matrices are zeros except main diagonal block matrices. These main diagonal block matrices are symmetrical and circulant matrices, and hence the solution of the associated linear algebraic system can be solved with the fast Fourier transform and the inverse fast Fourier transform instead of the inverse matrix. Finally, we provide several numerical examples to demonstrate our method has good accuracy even though the exact solutions are multi-peak and almost singular.

关键词： Trigonometric wavelet multiscale Galerkin method matrix decomposition FFT hypersingular integral equation harmonic equation.

Electrocatalytic C0_(2) Reduction with Re-Based Spiro Bipyridine Complexes: Effects of the Local Proton in the Second Coordination Sphere

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Chinese Journal of Chemistry 2021年第5期39卷 1281-1287页

作者： Yong Yang Ziyun Zhang Zhenyu Zhang Chao Tang Xiaoyong Chang Lele Duan Department of Chemistry Shenzhen Grubbs Institute and Guangdong Provincial Key Laboratory of Energy Materials for Electric PowerSouthern University of Science and TechnologyShenzhenGuangdong 518055China

We report herein a Re-based tricarbonyl catalyst[fac-Re(L1)(CO)_(3)Cl](Re1)bearing a spiro center and a phenol group as a local proton source in the second coordination *** to the large steric spiro group,dimerization of one-electron reduced species was completely eliminated,improving the stability of ***,the phenol group in the second coordination sphere improves the formation of an H-bonding chain that promotes the protonation of C0_(2) reduction intermediates,boosting the electrocatalytic C0_(2) reduction activity of *** studies reveal that the doubly reduced complex Re1b is active for C0_(2) addition.

关键词： Rhenium Homogeneous catalysis Second coordination sphere Electrochemistry CO_(2)reduction

Turbidity-adaptive underwater image enhancement method using image fusion

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Frontiers of Mechanical Engineering 2022年第3期17卷 261-279页

作者： Bin HAN Hao WANG Xin LUO Chengyuan LIANG Xin YANG Shuang LIU Yicheng LIN School of Mechanical science and Engineering Huazhong University of Science and TechnologyWuhan430074China guangdong Intelligent Robotics institute Dongguan523808China

Clear,correct imaging is a prerequisite for underwater *** real freshwater environment including rivers and lakes,the water bodies are usually turbid and dynamic,which brings extra troubles to quality of imaging due to color deviation and suspended *** of the existing underwater imaging methods focus on relatively clear underwater environment,it is uncertain that if those methods can work well in turbid and dynamic underwater *** this paper,we propose a turbidity-adaptive underwater image enhancement *** deal with attenuation and scattering of varying degree,the turbidity is detected by the histogram of *** on the detection result,different image enhancement strategies are designed to deal with the problem of color deviation and *** proposed method is verified by an underwater image dataset captured in real underwater *** result is evaluated by image metrics including structure similarity index measure,underwater color image quality evaluation metric,and speeded-up robust *** results exhibit that the method can correct the color deviation and improve the quality of underwater images.

关键词： turbidity underwater image enhancement image fusion underwater robots visibility