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Effect of movability of water on the low-velocity pre-Darcy flow in clay soil

Journal of Rock Mechanics and Geotechnical Engineering 2024年第8期16卷 3299-3310页

作者： Hui Cheng Fugang Wang Shengwei Li Xiaotong Guan Guohua Yang Zhongle Cheng Ceting Yu Yilong Yuan Guanhong Feng Key Laboratory of Groundwater Resources and Environment Ministry of EducationJilin UniversityChangchun130012China Jilin Provincial Key Laboratory of Water Resources and Water Environment Jilin UniversityChangchun130012China Chengdu Center China Geological SurveyChengdu610081China

Water seepage in soil is a fundamental problem involving various scientific and engineering *** to the literature,low-velocity water seepage in low-permeability porous media,such as clay,does not follow Darcy's law,also known as pre-Darcy *** formation of immovable water due to water adsorption on the pore wall is believed to be responsible for the formation of pre-Darcy ***,this view lacks direct solid *** investigate the pre-Darcy water flow in clay,head permeability experiments are conducted on six clay samples with different *** results indicate that water seepage in clay at low hydraulic gradients does not follow Darcy's law.A clear nonlinear relationship between flow velocity and hydraulic gradient is *** flow in clay can be divided into the pre-Darcy flow and Darcy flow regions by the critical hydraulic gradient,which is 10-12 for the Albic soil with dry density between 1.3 g/cm^(3)and 1.8 g/cm^(3).According to the disjoining pressure theory,immovable water due to water adsorption on the pore wall is the primary reason for water flow deviating from Darcy's law in *** results indicate that the percentage of movable water ranges from 39.7%to 59.3%for the six samples at a hydraulic gradient of *** the hydraulic gradient increases,the percentage of moveable water also ***,there is a strong correlation between the percentage of movable water and the variation in hydraulic conductivity with the hydraulic ***,a quantitative relationship between the percentage of movable water and the hydraulic conductivity has been *** results of this study suggest that water adsorption on the pore wall not only affects the water movability,but is also closely related to the pre-Darcy flow phenomenon in clay.

关键词： Pre-Darcy flow Clay Critical hydraulic gradient Water movability analysis

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Random Green's Function Method for Large-Scale Electronic Structure Calculation

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Chinese Physics Letters 2024年第5期41卷 23-29页

作者：汤明发刘畅张爱霞张青云翟佳羽袁声军柯友启 School of Physical science and Technology ShanghaiTech UniversityShanghai 201210China Xiaogan Sichuang Information Technology Co. LTDXiaogan 432000China Institute of Mathematical sciences ShanghaiTech UniversityShanghai 201210China Key Laboratory of Artificial Micro-and Nano-structures of Ministry of Education and School of Physics and TechnologyWuhan UniversityWuhan 430072China Wuhan Institute of Quantum Technology Wuhan 430206China

We report a linear-scaling random Green's function(rGF) method for large-scale electronic structure calculation. In this method, the rGF is defined on a set of random states and is efficiently calculated by projecting onto Krylov subspace. With the rGF method, the Fermi–Dirac operator can be obtained directly, avoiding the polynomial expansion to Fermi–Dirac function. To demonstrate the applicability, we implement the rGF method with the density-functional tight-binding method. It is shown that the Krylov subspace can maintain at small size for materials with different gaps at zero temperature, including H_(2)O and Si clusters. We find with a simple deflation technique that the rGF self-consistent calculation of H_(2)O clusters at T = 0 K can reach an error of~ 1 me V per H_(2)O molecule in total energy, compared to deterministic calculations. The rGF method provides an effective stochastic method for large-scale electronic structure simulation.

关键词： calculation function method

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When quantum dots meet blue phase liquid crystal elastomers:visualized full-color and mechanically-switchable circularly polarized luminescence

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Light(science & Applications) 2024年第6期13卷 1210-1220页

作者： Shan Li Yuqi Tang Qingyan Fan Ziyuan Li Xinfang Zhang Jingxia Wang Jinbao Guo Quan Li Key Laboratory of Carbon Fibers and Functional Polymers Ministry of Educationand College of Materials Science and EngineeringBeijing University of Chemical Technology100029BeijingChina Institute of Advanced Materials and School of Chemistry and Chemical Engineering Southeast UniversityNanjing211189China Materials science Graduate Program Kent State UniversityKentOH44242USA CAS Key Laboratory of Bio-Inspired Materials and Interfacial sciences Technical Institute of Physics and ChemistryChinese Academy of Sciences100190BeijingChina

Polymer-based circularly polarized luminescence(CPL)materials with the advantage of diversified structure,easy fabrication,high thermal stability,and tunable properties have garnered considerable ***,adequate and precise tuning over CPL in polymer-based materials remains challenging due to the difficulty in regulating chiral ***,visualized full-color CPL is achieved by doping red,green,and blue quantum dots(QDs)into reconfigurable blue phase liquid crystal elastomers(BPLCEs).In contrast to the CPL signal observed in cholesteric liquid crystal elastomers(CLCEs),the chiral 3D cubic superstructure of BPLCEs induces an opposite CPL ***,this effect is entirely independent of photonic bandgaps(PBGs)and results in a high glum value,even without matching between PBGs and the emission bands of ***,the lattice structure of the BPLCEs can be reversibly switched via mechanical stretching force,inducing on-off switching of the CPL signals,and these variations can be further fixed using dynamic disulfide bonds in the ***,the smart polymer-based CPL systems using the BPLCEs for anti-counterfeiting and information encryption have been demonstrated,suggesting the great potential of the BPLCEs-based CPL active materials.

关键词： circular quantum crystal

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Approaching Ultimate Synthesis Reaction Rate of Ni-Rich Layered Cathodes for Lithium-Ion Batteries

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Nano-Micro Letters 2024年第10期16卷 392-402页

作者： Zhedong Liu Jingchao Zhang Jiawei Luo Zhaoxin Guo Haoran Jiang Zekun Li Yuhang Liu Zijing Song Rui Liu Wei-Di Liu Wenbin Hu Yanan Chen School of Materials science and Engineering Tianjin UniversityTianjin 300072People's Republic of China School of Materials science and Engineering Shandong University of Science and TechnologyQingdao 266590People's Republic of China Australian Institute of Bioengineering and Nanotechnology The University of QueenslandSt LuciaQLD 4072Australia

Nickel-rich layered oxide LiNi_(x)Co_(y)MnzO_(2)(NCM,x+y+z=1)is the most promising cathode material for high-energy lithium-ion ***,conventional synthesis methods are limited by the slow heating rate,sluggish reaction dynamics,high energy consumption,and long reaction *** overcome these chal-lenges,we first employed a high-temperature shock(HTS)strategy for fast synthesis of the NCM,and the approaching ultimate reaction rate of solid phase transition is deeply investigated for the first *** the HTS process,ultrafast average reaction rate of phase transition from Ni_(0.6)Co_(0.2)Mn_(0.2)(OH)_(2) to Li-containing oxides is 66.7(%s^(-1)),that is,taking only 1.5 *** ultrahigh heating rate leads to fast reaction kinetics,which induces the rapid phase transition of NCM *** HTS-synthesized nickel-rich layered oxides perform good cycling performances(94%for NCM523,94%for NCM622,and 80%for NCM811 after 200 cycles at 4.3 V).These findings might also assist to pave the way for preparing effectively Ni-rich layered oxides for lithium-ion batteries.

关键词： Nickel-rich layered oxides High-temperature shock Solid reaction kinetics Phase transition Reaction rate

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Deposition of thin TiO_(2)films on fluorophlogopite particle surface by CVD in fluidized bed reactor to prepare silver pearlescent pigments

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Particuology 2024年第6期89卷 88-98页

作者： Ming Liu Guoqiang Shao Pengpeng Lv Jun Li Qingshan Zhu State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China School of Chemical Engineering University of Chinese Academy of SciencesBeijing 100049China

Two critical parameters:Glossiness and chromaticity space of pearlescent pigments were evaluated based on crystallinity and grain *** the roughness and the vertical distance evolution along the surface of deposited TiO_(2)film are affected by the *** optimal crystallinity of TiO_(2)was deposited at the temperature of 350℃.The TiCl4 concentration effectively changed the grain ***,the high flow rate of fluidizing gas and optimal gas–solid ratio(<0.11 m^(3)/(kg h))restricted the change of TiCl_(4)concentrations in fluidized bed *** this case,the grain size of the deposited TiO_(2)film was about 55 *** on the grain size,the color of pearlescent pigments was adjusted by controlling the film thickness based on TiO_(2)***,the silver pearlescent pigment with high glossiness was prepared by chemical vapor deposition method in a fluidized bed reactor.

关键词： Fluidized bed chemical vapor deposition TiO_(2)film deposition Pearlescent pigment Free powder restrain Crystal growth

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Stabilizing perovskite precursors with the reductive natural amino acid for printable mesoscopic perovskite solar cells

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Journal of Energy Chemistry 2024年第3期90卷 32-39,I0003页

作者： Wenjing Hu Jian Yang Chuang Yang Xufeng Xiao Chaoyang Wang Zhaozhen Cui Qiaojiao Gao Jianhang Qi Minghao Xia Yaqiong Su Anyi Mei Hongwei Han Michael Gratzel Center for Mesoscopic Solar Cells Wuhan National Laboratory for OptoelectronicsKey Laboratory of Materials Chemistry for Energy Conversion and Storage of Ministry of Education Huazhong University of Science and TechnologyWuhan 430074HubeiChina School of Chemistry Xi'an Key Laboratory of Sustainable Energy Materials ChemistryState Key Laboratory of Electrical Insulation and Power EquipmentXi'an Jiaotong UniversityXi'an 710049ShaanxiChina

Solution processability significantly advances the development of highly-efficient perovskite solar ***,the precursor solution tends to undergo irreversible degradation reactions,impairing the device performance and ***,we utilize a reductive natural amino acid,Nacetylcysteine(NALC),to stabilize the precursor solution for printable carbon-based hole-conductorfree mesoscopic perovskite solar *** find that I_(2) can be generated in the aged solution containing methylammonium iodide(MI) in an inert atmosphere and speed up the MA-FA^(+)(formamidinium) reaction which produces large-size cations and hinders the formation of perovskite *** effectively stabilizes the precursor via its sulfhydryl group which reduces I_(2) back to I^(-)and provides H^(+).The NALC-stabilized precursor which is aged for 1440 h leads to devices with a power conversion efficiency equivalent to 98% of that for devices prepared with the fresh ***,NALC improves the device power conversion efficiency from 16.16% to 18.41% along with enhanced stability under atmospheric conditions by modifying grain boundaries in perovskite films and reducing associated defects.

关键词： Perovskite solar cells Perovskite precursor Degradation Stabilization Reductive natural amino acid

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Tailored multifunctional hydrazine derivatives for efficient printable hole-conductive-free mesoscopic perovskite solar cells via enhancing defect passivation

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Journal of Energy Chemistry 2024年第8期95卷 357-363,I0008页

作者： Minghao Xia Ziwei Zheng Yanjie Cheng Chaoyang Wang Zhaozhen Cui Guodong Zhang Jinwei Gonga Anyi Mei Hongwei Han Michael Grätzel Center for Mesoscopic Solar Cells Wuhan National Laboratory for OptoelectronicsKey Laboratory of Materials Chemistry for Energy Conversion and Storage of Ministry of EducationHuazhong University of Science and TechnologyWuhan 430074HubeiChina Key Laboratory of Flexible Electronics(KLoFE)&Institute of Advanced Materials(IAM) School of Flexible Electronics(Future Technologies)Nanjing Tech University(NanjingTech)Nanjing 211816JiangsuChina

The low-cost and easy large-scale fabrication advantages of printable mesoscopic perovskite solar cells(p-MPSCs)are overshadowed by their limited photovoltaic conversion efficiency(PCE).Here,we introduce the hydrazide derivative of 4-Hydroxybenzoylhydrazine(4-HBH)to improve the PCE of p-MPSCs by inducing enhanced defect *** carbonyl and hydrazine groups in hydrazide groups present strong interaction with *** hydroxyl group,as an electron donor group,increases the electron cloud density of the hydrazide group in 4-HBH under the conjugation of the benzene ring,and thus enhances its interaction with ***,the hydroxy group itself interacts with perovskite and passivates defects *** hydrazine agents can also reduce I2and suppress the loss of iodine in perovskite films,which inhibits the formation of iodine-related ***,p-MPSCs with 4-HBH achieve a high PCE of 19.21%,and present well improved stability.

关键词： Printable mesoscopic perovskite solar cells Multifunctional hydrazine derivatives Cooperative coordination Conjugation redox activity

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Morphological characteristics and evolution model of slope units along loess gully cross section

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Frontiers of Earth science 2024年第1期18卷 17-29页

作者： Lulu LIU Fayuan LI Xue YANG Jianhua CHENG School of Geography Nanjing Normal UniversityNanjing 210023China Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application Nanjing 210023China Key Laboratory of Virtual Geographic Environment(Ministry of Education) Nanjing Normal UniversityNanjing 210023China

Gully morphology is an important part of loess landform *** with gully development,the variation of its cross section is the most significant,and it can intuitively reflect the characteristics of the lateral widening of the gully ***,in-depth research of the variation of the cross-sectional morphology of the gully is helpful to understanding the development process of the loess *** on the DEMs(Digital Elevation Model)of nine periods of an indoor simulated loess small watershed,this paper studies the evolution model of a complete branch ditch in the watershed using the digital terrain analysis theory and *** show that with the development of the gully,the average gradient of the gully slope continuously decreases,and the slope morphology is mostly a concave slope along the slope *** degree of downward concave first increases and then gradually tends to be *** gully erosion mode is gradually transformed from downward cutting erosion to lateral *** more mature the gully development,the lower the depth of gully bottom cutting is compared with the width of gully ***,the surface cutting depth tends to be stable and the slope is ***,the transformation law of the slope morphology of the gully cross section with the development of the gully is studied,and the prediction model of the transformation of the slope morphology of the gully cross section is established by using the Markov *** Markov model can better reflect the dynamic change of the slope morphology of the gully cross section,which is of great significance to revealing the external performance and internal mechanism of the gully morphology.

关键词： gully cross section slope morphology Markov chain digital elevation model

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Record-breaking High-temperature Outlook for 2023: An Assessment Based on the china Global Merged Temperature(CMST) Dataset

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Advances in Atmospheric sciences 2024年第2期41卷 369-376页

作者： Zichen LI Qingxiang LI Tianyi CHEN School of Atmospheric sciences and Guangdong Province Key Laboratory for Climate Change and Natural Disasters SUN Yat-Sen UniversityZhuhai 519082China Research Center for Ecology and Environment of Central Asia Chinese Academy of SciencesUrumqi 830011China Southern Laboratory of Ocean science and Engineering(Guangdong Zhuhai) Zhuhai 519082China

According to the latest version(version 2.0) of the china global Merged Surface Temperature(CMST2.0) dataset, the global mean surface temperature(GMST) in the first half of 2023 reached its third warmest value since the period of instrumental observation began, being only slightly lower than the values recorded in 2016 and 2020, and historically record-breaking GMST emerged from May to July 2023. Further analysis also indicates that if the surface temperature in the last five months of 2023 approaches the average level of the past five years, the annual average surface temperature anomaly in 2023 of approximately 1.26°C will break the previous highest surface temperature, which was recorded in 2016of approximately 1.25°C(both values relative to the global pre-industrialization period, i.e., the average value from 1850 to1900). With El Ni?o triggering a record-breaking hottest July, record-breaking average annual temperatures will most likely become a reality in 2023.

关键词： CMST2.0 global mean surface temperature record-breaking temperature El Ni?o

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Evolution of mechanical parameters of Shuangjiangkou granite under different loading cycles and stress paths

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第4期16卷 1113-1126页

作者： Liangjie Gu Xia-Ting Feng Rui Kong Chengxiang Yang Yuelin Xia Key Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines Northeastern UniversityShenyang110819China State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China

Surrounding rocks at different locations are generally subjected to different stress paths during the process of deep hard rock *** this study,to reveal the mechanical parameters of deep surrounding rock under different stress paths,a new cyclic loading and unloading test method for controlled true triaxial loading and unloading and principal stress direction interchange was proposed,and the evolution of mechanical parameters of Shuangjiangkou granite under different stress paths was studied,including the deformation modulus,elastic deformation increment ratios,fracture degree,cohesion and internal friction ***,stress path coefficient was defined to characterize different stress paths,and the functional relationships among the stress path coefficient,rock fracture degree difference coefficient,cohesion and internal friction angle were *** results show that during the true triaxial cyclic loading and unloading process,the deformation modulus and cohesion gradually decrease,while the internal friction angle gradually increases with increasing equivalent crack *** stress path coefficient is exponentially related to the rock fracture degree difference *** the stress path coefficient increases,the degrees of cohesion weakening and internal friction angle strengthening decrease *** cyclic loading and unloading under true triaxial principal stress direction interchange,the direction of crack development changes,and the deformation modulus increases,while the cohesion and internal friction angle decrease slightly,indicating that the principal stress direction interchange has a strengthening effect on the surrounding ***,the influences of the principal stress interchange direction on the stabilities of deep engineering excavation projects are discussed.

关键词： Triaxial cyclic loading and unloading test Stress path Deformation modulus and elastic deformation increment ratios Fracture degree Cohesion and internal friction angle

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