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Helmholtz decomposition with a scalar Poisson equation in elastic anisotropic media

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Petroleum Science 2024年第3期21卷 1597-1610页

作者： Xin-Yu Fang Gang Yao Qing-Qing Zheng Ping-min Zhang di Wu Feng-Lin niu State Key Laboratory of Petroleum Resources and Engineering China University of Petroleum(Beijing)Beijing102249China Unconventional Petroleum Research Institute China University of Petroleum(Beijing)Beijing102249China Department of Mathematics College of ScienceChina University of Petroleum(Beijing)Beijing102249China College of Geophysics China University of Petroleum(Beijing)Beijing102249China Department of Earth Environmental and Planetary SciencesRice UniversityHoustonTX77005UA

P-and S-wave separation plays an important role in elastic reverse-time *** can reduce the artifacts caused by crosstalk between different modes and improve image *** addition,P-and Swave separation can also be used to better understand and distinguish wave types in complex *** present,the methods for separating wave modes in anisotropic media mainly include spatial nonstationary filtering,low-rank approximation,and vector Poisson *** of these methods require multiple Fourier transforms or the calculation of large matrices,which require high computational costs for problems with large *** this paper,an efficient method is proposed to separate the wave mode for anisotropic media by using a scalar anisotropic Poisson operator in the spatial *** 2D problems,the computational complexity required by this method is 1/2 of the methods based on solving a vector Poisson ***,compared with existing methods based on pseudoHelmholtz decomposition operators,this method can significantly reduce the computational *** examples also show that the P and S waves decomposed by this method not only have the correct amplitude and phase relative to the input wavefield but also can reduce the computational complexity significantly.

关键词： Anisotropic media Scalar anisotropic Poisson equation Improved elastic wavefield decomposition

Flame Morphology and Characteristic of Co-Firing Ammonia with Pulverized Coal on a Flat Flame Burner

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Journal of Thermal Science 2024年第5期33卷 1935-1945页

作者： WANG Shengye CUI mingshuang LIU Pengzhong di Yi niu Fang China Coal Research Institute Beijing 100013China Beijing Tiandi Rongchuang Technology Co.Ltd. Beijing 100013China National Energy Technology&Equipment Laboratory of Coal Utilization and Emission Control Beijing 100013China

Ammonia as a new green carbon free fuel co-combustion with coal can effectively reduce CO_(2)emission,but the research of flame morphology and characteristics of ammonia-coal co-combustion are not *** this work,we studied the co-combustion flame of NH_(3)and pulverized coal on flat flame burner under different oxygen mole fraction(X_(i,O_(2)))and NH_(3)co-firing energy ratios(E_(NH_(3))).We initially observed that the introduction of ammonia resulted in stratification within the ammonia-coal co-combustion flame,featuring a transparent flame at the root identified as the ammonia combustion *** to challenges in visually observing the ignition of coal particles in the ammonia-coal co-combustion flame,we utilized Matlab software to analyze flame images across varying E_(NH_(3))and X_(i,O_(2)).The analysis indicates that,compared to pure coal combustion,the addition of ammonia advances the ignition delay time by 4.21 ms to 5.94 *** E_(NH_(3))increases,the ignition delay time initially decreases and then ***,an increase in X_(i,O_(2))results in an earlier ignition delay *** burn-off time and the flame divergence angle of pulverized coal demonstrated linear decreases and increases,respectively,with the growing ammonia *** addition of ammonia facilitates the release of volatile matter from coal ***,in high-ammonia environments,oxygen consumption also impedes the surface reaction of coal ***,measurements of gas composition in the ammonia-coal flame flow field unveiled that the generated water-rich atmosphere intensified coal particle gasification,resulting in an elevated concentration of ***,nitrogen-containing substances and coke produced during coal particle gasification underwent reduction reactions with NO_(x),leading to reduced NO_(x)emissions.

关键词： co-firing ammonia with coal flame characteristic gas component ignition delay time burn-off time flame divergence angle flat flame burner flame morphology

Consistency of Tropospheric Water Vapor between Reanalyses and Himawari-8/AHI Measurements over East Asia

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Advances in Atmospheric Sciences 2024年第1期41卷 19-38页

作者： di di Jun LI Yunheng XUE min min Bo LI Zhenglong LI Collaborative Innovation Center on Forecast and Evaluation of Meteorological disasters Nanjing University of Information Science and TechnologyNanjing 210044China Key Laboratory for Aerosol-Cloud-Precipitation China Meteorological AdministrationSchool of Atmospheric PhysicsNanjing University of Information Science and TechnologyNanjing 210044China FYSIC National Satellite Meteorological CenterChina Meteorological AdministrationBeijing 100081China Chengdu University of Information Science and Technology Chengdu 610225China School of Atmospheric Sciences and Guangdong Province Key laboratory for Climate Change and Natural disaster Studies Sun Yat-sen University and Southern Laboratory of Ocean Science and EngineeringZhuhai 519082China Cooperative Institute for Meteorological Satellite Studies University of Wisconsin–MadisonMadison WI 53706WisconsinUSA Wuxi University Wuxi 214105China

High spatiotemporal resolution radiances from the advanced imagers onboard the new generation of geostationary weather satellites provide a unique opportunity to evaluate the abilities of various reanalysis datasets to depict multilayer tropospheric water vapor(WV),thereby enhancing our understanding of the deficiencies of WV in reanalysis *** on daily measurements from the Advanced Himawari Imager(AHI)onboard the Himawari-8 satellite in 2016,the bias features of multilayer WV from six reanalysis datasets over East Asia are thoroughly *** assessments show that wet biases exist in the upper troposphere in all six reanalysis datasets;in particular,these biases are much larger in ***,we find better depictions of WV in the middle troposphere than in the upper *** accuracy of WV in the ERA5 dataset is the highest,in terms of the bias magnitude,dispersion,and pattern *** characteristics of the WV bias over the Tibetan Plateau are significantly different from those over other parts of East *** addition,the reanalysis datasets all capture the shift of the subtropical high very well,with ERA5 performing better overall.

关键词： AHI reanalysis dataset multilayer water vapor assessment radiative transfer model

OsPDR20 is an ABCG metal transporter regulating cadmium accumulation in rice

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Journal of Environmental Sciences 2024年第2期136卷 21-34页

作者： He Li Chao Li di Sun Zhi min Yang Department of Biochemistry and Molecular Biology College of Life SciencesNanjing Agricultural UniversityNanjing 210095China

Cadmium(Cd)is a non-essential toxic heavy metal,seriously posing high environmental risks to human *** genetic resources relevant to functional genes is important for understanding the metal absorption and accumulation in crops and bioremediation of Cd-polluted *** study investigated a functionally uncharacterized ATP binding cassette transporter G family(ABCG)gene encoding a Pleiotropic Drug Resistance 20(PDR20)type metal transporter which is localized to the plasma membrane of ***20 was transcriptionally expressed in almost all tissues and organs in lifespan and was strongly induced in roots and shoots of young rice under Cd *** expression of OsPDR20 in a yeast mutant ycf1 sensitive to Cd conferred cellular tolerance with less Cd *** of OsPDR20 by RNA interference(RNAi)moderately attenuated root/shoot elongation and biomass,with reduced chlorophylls in rice grown under hydroponic medium with 2 and 10μmol/L Cd,but led to more Cd accumulation.A field trial of rice grown in a realistic Cd-contaminated soil(0.40 mg/kg)showed that RNAi plants growth and development were also compromised compared to wild-type(WT),with smaller panicles and lower spikelet fertility but little effect on yield of ***,OsPDR20 suppression resulted in unexpectedly higher levels of Cd accumulation in rice straw including lower leaves and culm and *** results suggest that OsPDR20 is actively involved in Cd accumulation and homeostasis in rice *** increased Cd accumulation in the RNAi plants has the potential application in phytoremediation of Cd-polluted wetland soils.

关键词： Rice ABCG transporter Cadmium accumulation Phytoremediation

Sliding behaviors of the trapezoidal roof rock block under a lateral dynamic disturbance

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第3期16卷 741-760页

作者： Feng Dai Wancheng Zhu min Ren Shunchuan Wu Leilei niu Faculty of Land Resources Engineering Kunming University of Science and TechnologyKunming650093China Center for Rock Instability and Seismicity Research Department of Mining EngineeringSchool of Resource and Civil EngineeringNortheastern UniversityShenyang110819China

The surrounding rock of underground space is always affected by external dynamic disturbance from the side position,such as blasting vibration from a stope at the same level or seismic waves from adjacent strata.A series of laboratory tests,numerical simulations and theoretical analyses were carried out in this study to disclose the sliding mechanism of roof rock blocks under lateral ***,the experiments on trapezoidal key block under various clamping loads and disturbance were conducted,followed by numerical simulations using the fast Lagrangian analysis of continua(FLAC3D).Then,based on the conventional wave propagation model and the classical shear-slip constitutive model,a theoretical model was proposed to capture the relative displacement between blocks and the sliding displacement of the key *** results indicate that the sliding displacement of the key block increased linearly with the disturbance energy and decreased exponentially with the clamping load when the key block was disturbed to slide(without instability).Meanwhile,when the key block was disturbed to fall,two types of instability process may appear as immediate type or delayed *** addition,the propagation of stress waves in the block system exhibited obvious low-velocity and lowfrequency characteristics,resulting in the friction reduction effect appearing at the contact interface,which is the essential reason for the sliding of rock *** results can be applied to practical underground engineering and provide valuable guidance for the early detection and prevention of rockfalling disasters.

关键词： Lateral dynamic disturbance Trapezoidal rock block system Low-velocity and low-frequency wave Friction reduction effect Instability mode

An advanced 2D/3D g-C_(3)N_(4)/TiO_(2)@MnO_(2) multifunctional membrane for sunlight-driven sustainable water purification

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Nano Research 2024年第4期17卷 2368-2380页

作者： Fan Yu Chunjia Luo Xiaohan niu min Chao Pengfei Zhang Luke Yan Polymer Materials&Engineering Department School of Materials Science&EngineeringChang’an UniversityXi’an 710064China Key Laboratory of Road Construction Technology and Equipment MOEChang’an UniversityXi’an 710064China School of Textile Science and Engineering Xi’an Polytechnic UniversityXi’an 710064China

Graphitic carbon nitride(g-C_(3)N_(4))nanosheets have attracted widespread interest in the construction of advanced separation ***,dense stacking and a single functionality have limited the membrane ***,an advanced two-/three-dimensional(2D/3D)g-C_(3)N_(4)/TiO_(2)@MnO_(2) membrane is constructed by intercalating 3D TiO_(2)@MnO_(2) nanostructures into g-C_(3)N_(4) *** 3D flower-like nanostructures broaden the transport channels of the composite *** membrane can effectively separate five oil-in-water(O/W)emulsions,with a maximum flux of 3265.67±15.01 L·m^(-2)·h^(-1)·bar^(-1) and a maximum efficiency of 99.69%±0.45%for toluene-in-water emulsion(T/W).Meanwhile,the TiO_(2)@MnO_(2) acts as an excellent electron acceptor and provides positive spatial separation of electrons–holes(e^(-)–h^(+)).The formation of 2D/3D heterojunctions allows the material with wider light absorption and smaller bandgap(2.10 eV).These photoelectric properties give the membrane good degradation of three different pollutants,with about 100%degradation for methylene blue(MB)and malachite green(MG).The photocatalytic antibacterial efficiency of the membrane is also about 100%.After cyclic experiment,the membrane maintains its original separation and photocatalytic *** remarkable multifunctional and self-cleaning properties of the g-C_(3)N_(4) based membrane represent its potential value for complex wastewater treatment.

关键词： graphitic carbon nitride(g-C_(3)N_(4))based membrane three-dimensional(3D)nanostructures self-cleaning multifunction

Enhanced thermal conductivity and mechanical properties of 2D C_(f)/SiC composites modified by in-situ grown carbon nanotubes

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Journal of Advanced Ceramics 2024年第1期13卷 19-33页

作者： Changhui niu Qing Zhang Laifei Cheng Fang Ye Litong Zhang min Huang Tao Yang Science and Technology on Thermostructure Composite Materials Laboratory Northwestern Polytechnical UniversityXi’an 710072China Civil Aviation Department Zhejiang Institute of CommunicationsHangzhou 311112China Zhejiang Provincial Key Laboratory for Cutting Tools Taizhou UniversityTaizhou 318000China

In this work,the effects of carbon nanotubes(CNTs)on the microstructure evolution,thermal conductivity,and mechanical properties of C_(f)/SiC composites during chemical vapor infiltration(CVI)densification were investigated in *** with composites without CNTs,the thermal conductivity,flexural strength,flexural modulus,fracture toughness,interfacial shear strength,and proportional limit stress of specimens with CNTs of 4.94 wt%were improved by 117%,21.8%,67.4%,10.3%,36.4%,and 71.1%,*** improvement was attributed to the role of CNTs in the division of inter-layer pores,which provided abundant vapor growth sites for the ceramic matrix and promoted densification of the whole *** addition,the high thermal conductivity network formed by the overlap of CNTs and the rivet strengthening effect of CNTs were beneficial for synergistic improvement of thermal conductivity and mechanical properties of the ***,this study has practical significance for the development of thermal protection composite components with enhanced thermal conductivity and mechanical characteristics.

关键词： ceramic−matrix composites carbon nanotubes microstructure thermal conductivity mechanical properties

Nonlocal coherence harvesting from quantum vacuum

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Communications in Theoretical Physics 2024年第7期76卷 44-51页

作者： Rui-di Wang Shu-min Wu Xiao-Li Huang Department of Physics Liaoning Normal UniversityDalian 116029China

It is well known that nonlocal coherence reflects nonclassical correlations better than quantum entanglement. Here, we analyze nonlocal coherence harvesting from the quantum vacuum to particle detectors adiabatically interacting with a quantum scalar field in minkowski *** find that the harvesting-achievable separation range of nonlocal coherence is larger than that of quantum entanglement. As the energy gap grows sufficiently large, the detectors harvest less quantum coherence, while the detectors could extract more quantum entanglement from the vacuum state. Compared with the linear configuration and the scalene configuration, we should choose the model of equilateral triangle configuration to harvest tripartite coherence from the vacuum. Finally, we find a monogamous relationship, which means that tripartite l_(1)-norm of coherence is essentially bipartite types.

关键词： nonlocal coherence quantum vacuum monogamous relationship

Effectively improving the extreme-pressure capacity of a class of intercalated zirconium phosphate materials

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Science China(Technological Sciences) 2024年第3期67卷 753-764页

作者： niu WenXing ZHAO XinRui YUAN min HOU ZhiGuo LIU Lei XU Hong DONG JinXiang Shanxi Key Laboratory of Chemical Product Engineering Cllege of Chemical Engineering and TechnologyTaiyuan University of TechnologyTaiyuan 030024China School of Chemical and Environmental Engineering Pingdingshan UniversityPingdingshan 467000China

We studied different long-chain ammonium ions intercalated zirconium phosphate α-ZrP, methylamine intercalated ZrP(MAZrP), tetramethylammonium hydroxide intercalated ZrP(TMAH-ZrP), dodecyltrimethylammonium bromide intercalated ZrP(DTAB-ZrP), and stearyl trimethyl ammonium bromide intercalated ZrP(STAB-ZrP) as grease co-additives in combination with isobutylene sulfide(SIB). The grease with co-additives displayed excellent extreme-pressure and anti-wear ***, the combination of the longest chain ammonium ion intercalated zirconium phosphate, STAB-ZrP/SIB, had the best tribological properties. In comparison to α-ZrP, the advantage of STAB-ZrP was that it did not form a large area of the dense physical film like α-ZrP on the worn surface, but rather gave the SIB a chance to contact with the fresh metal surface to generate a chemical film. Therefore, the sub-micron physical film and nanoscale chemical film always exist side by side on the contact surface during the friction process. This intercalated α-ZrP/SIB additive has great potential for use in harsh operating conditions.

关键词： intercalatedα-ZrP/SIB physical film chemical film tribological properties