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Coccolith Assemblages and Primary Productivity Variations in the Central Western Pacific Warm Pool Over the Last 380 kyr

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Journal of Ocean University of China 2018年第3期17卷 563-570页

作者： liang dan LIU Chuanlian State Key Laboratory of Marine Geology Tongji University Library Tongji University

Coccolith assemblages in two gravity cores(KX21-2 and KX12-1) from the central Western Pacific Warm Pool(WPWP) have been analyzed with SYRACO. The variations of nutricline and primary productivity(PP) have been reconstructed based on these assemblages. The results show that the coccolith assemblages were dominated by Florisphaera profunda, Gephyrocapsa and Emiliania huxleyi over the last 380 kyr. Variations of nutricline and primary productivity can be divided into three intervals. Interval I(about 380–300 kyr): PP was high and nutricline was shallow; Interval II(about 300–160 kyr): PP decreased dramatically for a short time after the acme of G. caribbeanica in Mid-Brunhes while nutricline became deeper; Interval III(about 160 kyr–present): PP fluctuated at low levels and nutricline was deep. Variations of each coccolith taxon and PP were highly correlated in the two cores, which means that the geological environment is similar in the two cores. Spectrum analysis is performed for all coccolith taxons and PP, and the 19-kyr cycle is the most prominent. It means that the production of coccolithophores in the WPWP is mainly controlled by precession.

关键词： coccolith assemblage Western Pacific Warm Pool primary productivity nutricline precession

Variations and Controlling Factors of the Coccolith Weight in the Western Pacific Warm Pool over the Last 200 ka

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Journal of Ocean University of China 2016年第3期15卷 456-464页

作者： liang dan LIU Chuanlian State Key Laboratory of Marine Geology Tongji University

Using a coccolith weight analytic software(Particle Analyser), we analyze most abundant coccolith species in a sediment core from the central Western Pacific Warm Pool(WPWP) and calculate coccolith size and weight variations over the last 200 ka. These variations are compared with the trends of sea surface temperature(SST), primary productivity(PP), sea surface salinity(SSS), and insolation. Our results demonstrate that the size and weight of the coccoliths varied in response to variations of these factors, and their average total weight is primarily related to the relative abundance of the dominant species GEO(Gephyrocapsa oceanica). The variation in weight of EMI(Emiliania huxleyi) and GEE(Gephyrocapsa ericsonii) are mainly influenced by nutrients, and the variation of GEM(G. muellerae conformis) and GEO(G. oceanica) weight are mainly influenced by SST. For all of the taxa weight, PP and SST present apparent precession or semi-precession cycles, we consider that the mono-coccolith weight of the Equatorial Western Pacific is primarily affected by precession drived thermocline and nutricline variation.

关键词： Western Pacific Warm Pool coccolith weight analysis primary productivity precession

Lower Triassic Smithian-Spathian Boundary at West Pingdingshan Section in Chaohu,Anhui Province

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Science China Earth Sciences 2011年第3期54卷 372-379页

作者： liang dan TONG JinNan ZHAO LaiShi Key Laboratory of Biogeology and Environmental Geology of the Ministry of Education (China University of Geosciences) Wuhan 430074 China State Key Laboratory of Geological Processes and Mineral Resources (China University of Geosciences) Wuhan 430074 China

The West Pingdingshan Section in Chaohu, Anhui Province, has been extensively studied in recent years and become one of the classic Lower Triassic sequences well-clarified in multiple stratigraphies. Also it is an important section that defines the Smithian-Spathian (S-S) boundary within the Olenekian Stage. The S-S boundary strata at the section are restudied in high-resolution conodont biostratigraphy and carbon isotopes. The refined S-S boundary defined by the FAD of conodont Neospathodus pingdingshanensis is at 30 cm above the base of Bed 52, corresponding to a rapid diversification of conodonts. A sharp positive shift of δ13Ccarb curve co-occurs at the S-S boundary and it can be used as a key reference to define the boundary. The defined S-S boundary position and carbon isotopes curve can be well correlated globally.

关键词： Early Triassic Smithian-Spathian boundary conodont carbon isotopes Chaohu Anhui

Quadrature-free spline method for two-dimensional Navier-Stokes equation

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Applied Mathematics(A Journal of Chinese Universities) 2008年第1期23卷 31-42页

作者： HU Xian-liang HAN dan-fu Dept. of Math. Zhejiang Univ. Hangzhou 310027 China.

In this paper, a quadrature-free scheme of spline method for two-dimensional Navier- Stokes equation is derived, which can dramatically improve the efficiency of spline method for fluid problems proposed by Lai and Wenston（2004）. Additionally, the explicit formulation for boundary condition with up to second order derivatives is presented. The numerical simulations on several benchmark problems show that the scheme is very efficient.

关键词： quadrature-free spline method Navier-Stokes equation.

Microstructure and wear resistance of CoCrNbNiW high-entropy alloy coating prepared by laser melting deposition

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Rare Metals 2019年第12期38卷 1153-1159页

作者： Yan-Jun Jia Han-Ning Chen Xiao-dan liang School of Mechanical Engineering Tianjin Polytechnic UniversityTianjin 300387China School of Computer Science and Technology Tianjin Polytechnic UniversityTianjin 300387China

The defect-free CoCrNbNiW high-entropy alloy coating was successfully prepared by laser melting deposition,and its microstructure and wear resistance were *** results showed that the microstructure of CoCrNbNiW high-entropy alloy coating consisted of fee phase rich in Nb and fee phase including un-melted W particles and rich in ***,an amount of fee phase was formed at the middle and top of coating,while the bcc phase rich in Cr was formed at the ***,the un-melted W particles were diffusely distributed in the ***,the microhardness of CoCrNbNiW high-entropy alloy coating was improved and was 2.78 times as high as that of *** wear loss and wear rate of coating were 0.26 and 0.23 times higher than those of substrate,*** wear resistance of substrate was obviously improved due to the preparation of CoCrNbNiW high-entropy alloy coating.

关键词： Microstructure High-entropy alloy Microhardness Wear resistance

Electrowetting-driven droplet shrinkage with tunable focus property

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Optoelectronics Letters 2022年第3期18卷 166-169页

作者： liang dan ZHAO Rui liang Zhongcheng KONG Meimei CHEN Tao Center of Optofluidic Technology College of Optoelectronic EngineeringNanjing University of Posts and TelecommunicationNanjing 210023China

In this paper, a non-conductive droplet driven by electrowetting(EW) with planar electrode in surrounding fluid is studied. COMSOL is employed to simulate the evolution of droplet shrinkage and the relative experimental setup is established to monitor the evolution of contact angle and height at different voltages. The droplet contracts inward and the corresponding contact angle/height increase when voltage increases. When the voltage ranges from 50 V to 140 V, the variation of the relative contact angles and height reach up to 118.78° and 3.194 mm, respectively. The system of silicon oil and surrounding liquid propylene glycol(PG) acts as a positive lens, whose focal length varies from 87.153 mm to 42.963 mm.

关键词： property propylene planar

Porous nickel–titanium alloy prepared by gel-casting

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Rare Metals 2014年第4期33卷 394-399页

作者： Bo-Hua Duan Hai-Xia Hong De-Zhi Wang Hui-Jiang Liu Xiao-Jia Dong dan-dan liang School of Materials Science and Engineering Central South University State Key Laboratory of Powder Metallurgy Central South University

To explore the preparation of porous nickel- titanium alloy with excellent properties, larger size and complex shape, the premixed powder of Ni and Ti with atomic ratio of 1：1 was shaped by gel-casting. The effects of solids loading and the content of dispersant on flow ability of nickel-titanium slurry and the mechanical properties of nickel-titanium sintered body were studied. The drying models under different solids loading were also discussed. The results show that the viscosity of slurries significantly increases with an increase in solids loading. After a proper process of drying, the green body with complex shape is obtained. The sintered body with porosity rate reaching up to 49.5 % and compression strength reaching to 364.74 MPa could meet the basic demands of implant materials.

关键词： Gel-casting Porous nickel-titanium alloy Solids loading Drying

Effects of W Addition on the Electrochemical Behaviour and Passive Film Properties of Fe-Based Amorphous Alloys in Acetic Acid Solution

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Acta Metallurgica Sinica(English Letters) 2018年第10期31卷 1098-1108页

作者： dan-dan liang Xian-Shun Wei Chun-Tao Chang Jia-Wei Li Yong Wang Xin-Min Wang Jun Shen School of Materials Science and Engineering Tongji University Key Laboratory of Magnetic Materials and Devices Ningbo Institute of Materials Technology and Engineering Chinese Academy of Sciences Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology Ningbo Institute of Materials Technology and Engineering Chinese Academy of Sciences School of Mechanical Science and Engineering Northeast Petroleum University

The electrochemical behaviour and passive film properties of Fe-Cr-Mo-W-C-B-Y amorphous alloys in acetic acid solution were investigated. The potentiodynamic polarisation and Nyquist curves demonstrated that W addition signifi- cantly enhanced the corrosion resistance. Mott-Schottky plots and angle-resolved X-ray photoelectron spectra indicated that passive films with different W contents exhibited dipolar （p-n） semiconducting characteristics separated by fiat-band potentials. The outer and inner oxide layers of the passive films were modified by reducing the acceptor and donor densities. Moreover, W addition favoured the formation of a thicker and more stable passive film to inhibit the dissolution of alloy elements.

关键词： Amorphous alloy XPS Mott-Schottky measurement Passive film Semiconducting property Chemical ingredient

Dynamically Characterizing the Structures of Dirac Points via Wave Packets

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Chinese Physics Letters 2023年第11期40卷 9-13页

作者：梁丹丹沈鑫李志 Key Laboratory of Atomic and Subatomic Structure and Quantum Control(Ministry of Education) Guangdong Basic Research Center of Excellence for Structure and Fundamental Interactions of MatterSchool of PhysicsSouth China Normal UniversityGuangzhou 510006China Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials Guangdong-Hong Kong Joint Laboratory of Quantum MatterFrontier Research Institute for PhysicsSouth China Normal UniversityGuangzhou 510006China College of Sciences China Jiliang UniversityHangzhou 310018China

Topological non-trivial band structures are the core problem in the field of topological *** investigate the topological band structure in a system with controllable Dirac points from the perspective of wave packet *** adding a third-nearest-neighboring coupling to the graphene model,additional pairs of Dirac points *** emergence and annihilation of Dirac points result in hybrid and parabolic points,and we show that these band structures can be revealed by the dynamical behaviors of wave *** particular,for the gapped hybrid point,the motion of the wave packet shows a one-dimensional Zitterbewegung ***,we also show that the winding number associated with the Dirac point and parabolic point can be determined via the center of mass and spin texture of wave packets,*** results of this work could motivate new experimental methods to characterize a system’s topological signatures through wave packet dynamics,which may also find applications in systems of other exotic topological materials.

关键词： Dirac topological parabolic