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Polarized imaging dynamic light scattering for simultaneous measurement of nanoparticle size and morphology

Particuology 2024年第2期85卷 213-223页

作者： Bingyao Wang Tianyi Cai Xiaoshu Cai Wu Zhou Zeqi Liu Schoolof Energy and Power Engineering University of Shanghai for Science and TechnologyShanghai200093China Shanghai Key Laboratory of Multiphase flow and Heat Transfer in Power Engineering Shanghai200093China Jiaxing MeaParTech Instrument Technology Co. LtdZhejiang314000China

The performance of nanoparticles is often affected by particle size and ***,electron microscopy or atomic force microscopy is typically utilized to determine the size and morphology of ***,there are issues such as difficult sample preparation,long processing times,and challenges in quantitative ***,it is of great significance to develop a fast,accu-rate,and statistical method to measure the size and morphology of *** this study,a new method,called polarized imaging dynamic light scattering(PIDLS),is *** nanoparticles are irradiated with a vertical linearly polarized laser beam,and a polarization camera collected the dynamic light scattering images of particles at four different polarization directions(0°,45°,90°,and 135°)at a scattering angle of 90°.The average particle size and distribution are obtained using the imaging dy-namic light scattering method at 0°polarization direction,and the morphology of the particles is ob-tained based on the depolarization patterns of the scattered *** optical sphericityΦis defined based on the degree of linear polarization(DoLP).It is also implemented for the quantitative evaluation of the sphericity of the nanoparticles,including spherical,octahedral,nanoplate,nanorod,and linear *** with the Poincarésphere parameterψ,the morphology of the nanoparticles can be roughly *** addition,PIDLS enables the measurement of particle size and morphology distributions simultaneously for evaluating the uniformity of *** effectiveness of PIDLS is verified by the measurement of five kinds of industrial titanium dioxide as well.

关键词： Imaging dynamic light scattering Polarized light scattering Non-spherical nanoparticles Morphology Online measurement

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Impact of Quantum Coherence on Inelastic Thermoelectric Devices:From Diode to Transistor

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Chinese Physics Letters 2024年第7期41卷 117-125页

作者：曹蓓韩崇泽郝翔王晨陆金成 Jiangsu Key Laboratory of Micro and Nano Heat Fluid flow Technology and Energy Application School of Physical Science and TechnologySuzhou University of Science and TechnologySuzhou 215009China Department of Physics Zhejiang Normal UniversityJinhua 321004China

We present a study on inelastic thermoelectric devices, wherein charge currents and electronic and phononic heat currents are intricately interconnected. The employment of double quantum dots in conjunction with a phonon reservoir positions them as promising candidates for quantum thermoelectric diodes and transistors. We illustrate that quantum coherence yields significant charge and Seebeck rectification effects. It is worth noting that, while the thermal transistor effect is observable in the linear response regime, especially when phononassisted inelastic processes dominate the transport, quantum coherence does not enhance thermal *** work may provide valuable insights for the optimization of inelastic thermoelectric devices.

关键词： quantum charge Quantum

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Experimental investigation for temperature and emissivity by flame emission spectrum in a cavity of rocket based combined cycle combustor chamber

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DEFENCE TECHNOLOGY 2024年第9期39卷 114-122页

作者： Cai, Weiguang Zheng, Shu Wang, Yan Liu, Bing Zhu, Shaohua Zhao, Li Lu, Qiang North China Elect Power Univ Natl Engn Res Ctr New Energy Power Generat Beijing 102206 Peoples R China Northwestern Polytech Univ Internal Flow & Thermal Struct Lab Sci & Technol Combust Xian 710072 Peoples R China

Flame temperature and spectral emissivity were the important parameters characterizing the sufficient degree of fuel combustion and the particle radiative characteristics in the Rocket Based Combined Cycle (RBCC) combustor. To investigate the combustion characteristics of the complex supersonic flame in the RBCC combustor, a new radiation thermometry combined with Levenberg-Marquardt (LM) algorithm and the least squares method was proposed to measure the temperature, emissivity and spectral radiative properties based on the flame emission spectrum. In-situ measurements of the flame temperature, emissivity and spectral radiative properties were carried out in the RBCC direct-connected test bench with laser-induced plasma combustion enhancement (LIPCE) and without LIPCE. The flame average temperatures at fuel global equivalence ratio (a) of 1.0b and 0.6 with LIPCE were 4.51% and 2.08% higher than those without LIPCE. The flame combustion oscillation of kerosene tended to be stable in the recirculation zone of cavity with the thermal and chemical effects of laser induced plasma. The differences of flame temperature at a = 1.0b and 0.6 were 503 K and 523 K with LIPCE, which were 20.07% and 42.64% lower than those without LIPCE. The flame emissivity with methane assisted ignition was 80.46% lower than that without methane assisted ignition, due to the carbon-hydrogen ratio of kerosene was higher than that of methane. The spectral emissivities at 600 nm with LIPCE were 1.25%, 22.2%, and 4.22% lower than those without LIPCE at a = 1.0a (with methane assisted ignition), 1.0b (without methane assisted ignition) and 0.6. The effect of concentration in the emissivity was removed by normalization to analyze the flame radiative properties in the RBCC combustor chamber. The maximum differences of flame normalized emissivity were 50.91% without LIPCE and 27.53% with LIPCE. The flame radiative properties were stabilized under the thermal and chemical effects of laser induced plasma

关键词： Rocket-based combined-cycle Supersonic combustion Flame temperature measurement Emissivity Laser induced plasma combustion enhancement STOKES-RAMAN SPECTROSCOPY

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Wave nature of Rosensweig instability

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Chinese Physics B 2024年第3期33卷 471-479页

作者：李柳李德才戚志强王璐张志力 School of Mechanical Electronicand Control EngineeringBeijing Jiaotong UniversityBeijing 100044China Beijing Key Laboratory of flow and Heat Transfer of Phase Changing in Micro and Small Scale Beijing 100044China State Key Laboratory of Tribology Tsinghua UniversityBeijing 100084China

The explicit analytical solution of Rosensweig instability spikes'shapes obtained by Navier-Stokes(NS)equation in diverse magnetic field H vertical to the flat free surface of ferrofluids are systematically studied experimentally and *** carefully analyzing and solving the NS equation in elliptic form,the force balanced surface equations of spikes in Rosensweig instability are expressed as cosine wave in perturbated magnetic field and hyperbolic tangent in large magnetic field,whose results both reveal the wave-like nature of Rosensweig *** results of hyperbolic tangent form are perfectly fitted to the experimental results in this paper,which indicates that the analytical solution is basically *** the forementioned theoretical results,the total energy of the spike distribution pattern is *** analyzing the energy components under different magnetic field intensities H,the hexagon-square transition of Rosensweig instability is systematically discussed and explained in an explicit way.

关键词： ferrofluids Rosensweig instability hexagon-square transition

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Magnetic and luminescent properties of bifunctional composite Fe_(3)O_(4)@Y_(2)O_(2)S:Eu^(3+)

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Journal of Rare Earths 2024年第8期42卷 1568-1576,I0006页

作者： Zhiqi Liang Zhili Zhang Liu Li Wen Xu Decai Li School of Mechanical Electronic and Control EngineeringBeijing Jiaotong UniversityBeijing100044China Beijing Key Laboratory of flow and Heat Transfer of Phase Changing in Micro and Small Scale Beijing100044China State Key Laboratory of Tribology Tsinghua UniversityBeijing100084China

As a kind of non-destructive testing method,magnetic particle inspection is widely used in the fields of aviation and high-speed *** properties of magnetic fluorescent bifunctional composites,such as fluorescence intensity and magnetic properties,have increasing demands in magnetic particle *** earth compounds offer potential as novel materials for fluorescent magnetic bifunctional composites due to their excellent optical properties and extremely narrow emission *** this work,the rare earth fluorescent material Y_(2)O_(2)S:Eu^(3+) was synthesized by solid-state reaction ***_(3)O_(4)nanoparticles prepared by hydrothermal method were uniformly coated on the Y_(2)O_(2)S:Eu^(3+) particles through physical adsorption of *** obtained Fe_(3)O_(4)@Y_(2)O_(2)S:Eu^(3+) exhibits dark red color under the ultraviolet *** additio n,X-ray diffractio n,morphology,photoluminescence and hyste resis loop of Fe_(3)O_(4)@Y_(2)O_(2)S:Cu^(3+) were *** luminescence mechanism of Y_(2)O_(2)S:Eu^(3+) is described in detail Fe_(3)O_(4)@Y_(2)O_(2)S:Cu^(3+) displays good paramagnetism and has a good controllability under a magnetic *** magnetic particle inspection of Fe_(3)O_(4)@Y_(2)O_(2)S:Eu^(3+) was performed using a 4-pole electromagnet and a test piece *** magnetic fluorescent bifunctional composite presented in this work can be applied for non-destructive testing.

关键词： Bifunctional material Fe_(3)O_(4) Y_(2)O_(2)S:Eu^(3+) Luminescence Solid-state reaction Rare earths

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Cosmological constraints from the joint analysis of clustering and lensing with the DESI Legacy Imaging Surveys

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Science China(Physics,Mechanics & Astronomy) 2024年第3期67卷 169-170页

作者： Surhud More Inter-University centre for Astronomy and Astrophysics Pune 411007India

The comparison between the amplitude of density fluctuations in matter today as inferred from the observations of the Cosmic Microwave background by the Planck collaboration [1] to that from the observations of the late Universe,is a stringent test of the concordance cosmological model. A joint analysis of the clustering of galaxies and their galaxygalaxy lensing signal is a unique way to constrain cosmological parameters.

关键词： galaxy parameters. galaxies

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High performance in Zintl thermoelectrics via reduction in crystal field splitting energy

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Science China Materials 2024年第10期67卷 3424-3425页

作者： Anustoop Das Kanishka Biswas New Chemistry Unit School of Advanced Materials and International Centre for Materials Science Jawaharlal Nehru Centre for Advanced Scientific Research(JNCASR)

Sustainable thermoelectric materials open an avenue of emission-free as well as fast-responding recycling of energy in terms of heat to *** efficiency （η） of such conversion is primarily guided by the dimensionless thermoelectric figure of merit （zT）,which depends on parameters like Seebeck coefficient （S）,electrical conductivity （σ）,and thermal conductivity（κ） at a given temperature （T）,which are adversely interrelated to each other （zT=S2σT/κ）[1,2].

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In-situ synthesis of quantum dots in the nucleus of live cells

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National Science Review 2024年第3期11卷 172-182页

作者： Yusi Hu Zhi-Gang Wang Haohao Fu Chuanzheng Zhou Wensheng Cai Xueguang Shao Shu-Lin Liu Dai-Wen Pang State Key Laboratory of Medicinal Chemical Biology Frontiers Science Centre for New Organic MatterTianjin Key Laboratory of Biosensing and Molecular Recognition Research Centre for Analytical Sciences College of Chemistry School of Medicine and Frontiers Science Centre for Cell Responses Nankai University Haihe Laboratory of Sustainable Chemical Transformations

The cell nucleus is the main site for the storage and replication of genetic material, and the synthesis of substances in the nucleus is rhythmic, regular and strictly regulated by physiological processes. However,whether exogenous substances, such as nanoparticles, can be synthesized in situ in the nucleus of live cells has not been reported. Here, we have achieved in-situ synthesis of CdSxSe1-xquantum dots（QDs） in the nucleus by regulation of the glutathione（GSH） metabolic pathway. High enrichment of GSH in the nucleus can be accomplished by the addition of GSH with the help of the Bcl-2 protein. Then, high-valence Se is reduced to low-valence Se by glutathione-reductase-catalyzed GSH, and interacts with the Cd precursor formed through Cd and thiol-rich proteins, eventually generating QDs in the nucleus. Our work contributes to a new understanding of the syntheses of substances in the cell nucleus and will pave the way for the development of advanced ‘supercells’.

关键词： glutathione live cell nucleus quantum dot intracellular synthesis

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Source parameters and aftershock pattern of the October 7,2021,M5.9 Harnai earthquake,Pakistan

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Earthquake Science 2024年第4期37卷 304-323页

作者： Mohammad Tahir Zeeshan Ahmad Sadia Sabahat Muhammad Naveed Mushtaq Talat Iqbal Muhammad Ali Shah Alam Aftab centre for Earthquake Studies National Centre for PhysicsIslamabad 44000Pakistan

On October 7,2021,a magnitude 5.9 earthquake struck the Harnai(Baluchistan)region of Pakistan,causing several fatalities and injuries within the epicentral ***-order tectonic deformation in this region is caused by the convergence of the Indian Plate with respect to the Eurasian *** Katwaz Block hinders the motion of the Indian Plate,resulting in the formation of strike-slip *** this study,the P-wave first-motion polarity technique was used to determine the mainshock faulting *** scanning of the polarity solutions was applied to determine the most suitable focal mechanism solution among the available solutions generated by the FOCMEC(focal mechanism)*** nodal planes correspond to different faulting styles(i.e.,thrust and strike-slip faulting).A nodal plane oriented in the NW-SE direction corresponded to a strike-slip mechanism,which was considered to be the fault ***,this earthquake was associated with the Harnai-Karahi strike-slip fault zone owing to the fault strike and direction of *** apparent stress drop,fault length,and moment magnitude of the Harnai earthquake were 35.4 bar,6.1 km,and 5.9,respectively.A lower b-value for the Gutenberg-Richter law was observed prior to the ***α-than b-values(α>b)indicate that this earthquake was governed by large events as opposed to small-magnitude *** Harnai sequence had a decay exponent close to unity,lasted for 145 days,and produced few *** study will help the future hazard mitigation in the region.

关键词： focal mechanism solution selection of fault plane FPFIT stress inversion oblique slip mechanism

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Investigations on affinity law under gas–liquid conditions in multistage radial and mixed-flow multiphase pumps

International Journal of Fluid Engineering

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International Journal of Fluid Engineering 2024年第1期 56-70页

作者： Liang Chang Chenyu Yang Xiaobin Su Xiaoyu Dai Qiang Xu Liejin Guo State Key Laboratory of Multiphase flow in Power Engineering Xi'an Jiaotong University

Affinity laws have been widely used in pump design and simulation under high-temperature and corrosive conditions. By applying such laws,it is possible to shorten development cycles and reduce test costs. However, current applications of affinity laws are still limited to liquid conditions. In this paper, expressions for affinity laws and their applicability are investigated for multistage radial and mixed-flow multiphase pumps under gas–liquid conditions. A high-pressure（30 MPa） gas–liquid experimental platform is constructed, and three-stage and 25-stage radial pumps and a 15-stage mixed-flow pump are investigated, with specific speeds of 107 and 216. With gas compressibility taken into account, the gas–liquid two-phase flow rate, head, and power, and the corresponding dimensionless hydraulic coefficients, are defined for multiphase pumps. The deterioration of gas–liquid pressurization performance is found to be divided into three processes with different dynamic mechanisms, corresponding to three flow patterns. The inlet gas volume fraction of pump is used to judge dynamic similarity. At the same inlet gas volume fractions λ1= λ2, when the gas–liquid flows in two pumps have the same flow pattern, dynamic similarity will be satisfied. The affinity law that is established shows good applicability to the three-stage radial multiphase pump, with goodness of fit R2larger than 0.9 for the two-phase Ψm–Φmand Πm–Φmperformance curves. Finally, experimental results indicate that the affinity law also has good applicability to multiphase pumps with different stage numbers and blade structures under gas–liquid conditions.

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