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Rebuilding the theory of isotope fractionation for evaporation of silicate melts under vacuum condition

Acta Geochimica 2024年第4期43卷 661-676页

作者： Jie Wang yun liu Research Center for Planetary Science College of Earth and Planetary SciencesChengdu University of TechnologyChengdu 610059China State Key Laboratory of Ore Deposit Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China CAS Center for Excellence in Comparative Planetology Hefei 230026China

Isotope eff ects are pivotal in understanding silicate melt evaporation and planetary accretion *** on the Hertz-Knudsen equation,the current theory often fails to predict observed isotope fractionations of laboratory experiments due to its oversimplified ***,we point out that the Hertz-Knudsen-equation-based theory is incomplete for silicate melt evaporation cases and can only be used for situations where the vaporized species is identical to the one in the *** propose a new model designed for silicate melt evaporation under *** model considers multiple steps including mass transfer,chemical reaction,and *** derivations reveal a kinetic isotopic fractionation factor(KIFF orα)αour model=[m(^(1)species)/m(^(2)species)]^(0.5),where m(species)is the mass of the reactant of reaction/nucleation-limiting step or species of diffusion-limiting step and superscript 1 and 2 represent light and heavy isotopes,*** model can eff ectively reproduce most reported KIFFs of laboratory experiments for various elements,i.e.,Mg,Si,K,Rb,Fe,Ca,and ***,the KIFF-mixing model referring that an overall rate of evaporation can be determined by two steps jointly can account for the eff ects of low P_(H2)pressure,composition,and *** addition,we find that chemical reactions,diffusion,and nucleation can control the overall rate of evaporation of silicate melts by using the fitting slope in ln(−ln f)versus ln(t).Notably,our model allows for the theoretical calculations of parameters like activation energy(E_(a)),providing a novel approach to studying compositional and environmental eff ects on evaporation processes,and shedding light on the formation and evolution of the proto-solar and Earth-Moon systems.

关键词： Evaporation Kinetic isotopic fractionation Chemical kinetics Hertz-Knudsen equation CAIS

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Nuclear volume effects in kinetic isotope fractionation:A case study of mercury oxidation by chlorine species

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Acta Geochimica 2024年第3期43卷 411-423页

作者： Chenlu Yang Yining Zhang yun liu Research Center for Planetary Science College of Earth and Planetary SciencesChengdu University of TechnologyChengdu 610059China State Key Laboratory of Ore Deposit Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China

It is well-known that the equilibrium isotope fractionation of mercury(Hg)includes classical massdependent fractionations(MDFs)and nuclear volume effect(NVE)induced mass-independent fractionations(MIFs).However,the effect of the NVE on these kinetic processes is not *** total fractionations(MDFs+NVEinduced MIFs)of several representative Hg-incorporated substances were selected and calculated with ab initio calculations in this work for both equilibrium and kinetic ***-induced MIFs were calculated with scaled contact electron densities at the nucleus through systematic evaluations of their accuracy and errors using the Gaussian09 and DIRAC19 packages(named the electron density scaling method).Additionally,the NVE-induced kinetic isotope effect(KIE)of Hg isotopes are also calculated with this method for several representative Hg oxidation reactions by chlorine *** KIEs for 202 Hg/^(198)Hg ranging from−2.27‰to 0.96‰are *** anomalous^(202)Hg-enriched KIEs(δ^(202)Hg/^(198)Hg=0.83‰,0.94‰,and 0.96‰,)caused by the NVE are observed,which are quite different from the classical view(i.e.,light isotopes react faster than the heavy ones).The electron density scaling method we developed in this study can provide an easier way to calculate the NVE-induced KIEs for heavy isotopes and serve to better understand the fractionation mechanisms of mercury isotope systems.

关键词： Nuclear volume effect Kinetic fractionation Hg isotopes Ab initio calculations

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Effect of the vortical structures on the hydrodynamic performance of a pitching hydrofoil

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Journal of Hydrodynamics 2024年第2期36卷 406-420页

作者： Rui Yuan Hui-yun Hao Qin Wu yun-qing liu Biao Huang School of Mechanical Engineering Beijing Institute of TechnologyBeijing100081China

The objective is to study the vortical structural behaviors of a transient pitching hydrofoil and their effects on the hydrodynamic performance. The pitching motion of the hydrofoil is set to pitch up with an almost constant rate from 5° to 15° and then back to 5°, with the Reynolds number 4.4×10^(5) and the frequency 2 Hz. The results show that the main coherent structures around the pitching hydrofoil include small-scale laminar separation bubble (LSB), large-scale second vortex (SV) and trailing edge vortex (TEV) which are all vortical. The relationship between the vortical structure and the lift is investigated with the finite-domain impulse theory. It indicates that the major part of the lift is contributed by the LSB, whereas the shedding and the formation of the SV and TEV cause the fluctuation of the lift. The proper orthogonal decomposition (POD) method is applied to capture the most energetic modes, revealing that the LSB mode occupies a large amount of energy in the flow field. The dynamic mode decomposition (DMD) method accurately extracts the dominant frequency and modal characteristics, with the first mode corresponding to the mean flow, the second mode corresponding to the LSB structure and the third and fourth modes corresponding to the vortex shedding.

关键词： Hydrodynamics vortical structures finite-domain impulse theory proper orthogonal decomposition(POD) dynamic mode decomposition(DMD) Pitching hydrofoil

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Theoretical study of kinetic isotope effects for vacancy diffusion of impurity in solids

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Acta Geochimica 2024年第5期43卷 959-970页

作者： Yuxi Jing Xuefang Li yun liu Research Center for Planetary Science College of Earth and Planetary SciencesChengdu University of TechnologyChengdu 610059China State Key Laboratory of Ore Deposit Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China CAS Center for Excellence in Comparative Planetology Hefei 230026China

Theoretical studies of the diffusionalisotope effect in solids are still stuck in the 1960s and *** the development of high spatial resolution mass spectrometers,isotopic data of mineral grains are rapidly *** dig up information from these data,molecularlevel theoretical models are urgently *** on the microscopic definition of the diffusion coe fficient(D),a new theoretical framework for calculating the diffusional isotope effect(DIE(v))(intermsofD*/D)forvacancy-mediated impurity diffusion in solids is provided based on statistical mechanics *** newly derived equation shows that theDIE(v)can be easily calculated as long as the vibration frequencies of isotope-substituted solids are *** calculatedDIE(v)values of^(199)Au/^(195)Au and^(60)Co/^(57)Co during diffusion in Cu and Au metals are all within 1%of errors compared to the experimental data,which shows that this theoretical model is reasonable and precise.

关键词： Vacancy diffusion Diffusional isotope effect Statistical mechanics

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Degradation-adaptive neural network for jointly single image dehazing and desnowing

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Frontiers of Computer Science 2024年第2期18卷 247-249页

作者： Erkang CHEN Sixiang CHEN Tian YE yun liu School of Ocean Information Engineering Jimei UniversityXiamen 361021 China College of Artificial Intelligence Southwest UniversityChongqing 400715 China

1 Introduction In harsh winter scenes,the captured images often suffer from hazeand snowdegradationssimultaneously,which significantly affect the performance of high-level computer vision ***,most existing dehazing methods[1-4]and desnowing methods[5-7]are specialized to address only one type of weather-related degradation,and they struggle to effectively handle multiple types of degradations.

关键词： neural handle computer

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A Non-Iterative Network Utilization Pricing Mechanism for P2P Energy Trading

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CSEE Journal of Power and Energy Systems 2024年第3期10卷 1301-1306页

作者： yun liu yunqiang Gao Yuanzheng Li Jizhong Zhu Hoay Beng Gooi School of Electric Power Engineering South China University of TechnologyGuangzhou 510641China School of Artificial Intelligence and Automation Ministry of Education Key Laboratory of Image Processing and Intelligence ControlHuazhong University of Science and TechnologyWuhan 430074China School of Electrical and Electronic Engineering Nanyang Technological UniversitySingapore IEEE

To sustain operation and maintenance of an active distribution network(ADN),a network fee should be charged by the distribution network service provider(DNSP)for facilitating the P2P energy trading *** this end,this paper models the interaction among the DNSP and multiple prosumers as a Stackelberg game,and then develops a non-iterative and decentralized transactive mechanism to simultaneously achieve optimal network utilization pricing and peer-to-peer(P2P)*** results in an ADN with four prosumers connected to a common substation bus validate the effectiveness and efficiency of the proposed scheme.

关键词： Distribution network service provider network fee non-iterative peer-to-peer trading prosumer

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An artificial intelligence diabetes management architecture based on 5G

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Digital Communications and Networks 2024年第1期10卷 75-82页

作者： Ruochen Huang Wei Feng Shan Lu Tao shan Changwei Zhang yun liu Department of Geriatrics The First Affiliated Hospital of Nanjing Medical UniversityNanjing210096China Department of Information The First Afliated Hospital of Nanjing Medical UniversityNanjing210096China Department of Medical Informatics School of Biomedical Engineering and InformaticsNanjing Medical UniversityNanjing211166China Department of Outpatient The First Affiliated Hospital of Nanjing Medical UniversityNanjing210096China Jiangsu Key Laboratory of Wireless Communications Nanjing University of Posts and TelecommunicationsNanjing210003China

Along with the development of 5G network and Internet of Things technologies,there has been an explosion in personalized healthcare *** the 5G and Artificial Intelligence(Al)is introduced into diabetes management architecture,it can increase the efficiency of existing systems and complications of diabetes can be handled more effectively by taking advantage of *** this article,we propose a 5G-based Artificial Intelligence Diabetes Management architecture(AIDM),which can help physicians and patients to manage both acute complications and chronic *** AIDM contains five layers:the sensing layer,the transmission layer,the storage layer,the computing layer,and the application *** build a test bed for the transmission and application ***,we apply a delay-aware RA optimization based on a double-queue model to improve access efficiency in smart hospital wards in the transmission *** application layer,we build a prediction model using a deep forest *** on real-world data show that our AIDM can enhance the efficiency of diabetes management and improve the screening rate of diabetes as well.

关键词： Diabetes 5G Artificial intelligence Deep forest Smart hospital ward

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MPI/OpenMP-Based Parallel Solver for Imprint Forming Simulation

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Computer Modeling in Engineering & Sciences 2024年第7期140卷 461-483页

作者： Yang Li Jiangping Xu yun liu Wen Zhong Fei Wang School of Mechanical Engineering Jiangsu UniversityZhenjiang212016China School of Mechanical Engineering Wuhan Polytechnic UniversityWuhan430023China Shenyang Mint Company Limited Shenyang110092China

In this research,we present the pure open multi-processing(OpenMP),pure message passing interface(MPI),and hybrid MPI/OpenMP parallel solvers within the dynamic explicit central difference algorithm for the coining process to address the challenge of capturing fine relief features of approximately 50 *** such precision demands the utilization of at least 7 million tetrahedron elements,surpassing the capabilities of traditional serial programs previously *** mitigate data races when calculating internal forces,intermediate arrays are introduced within the OpenMP *** helps ensure proper synchronization and avoid conflicts during parallel ***,in the MPI implementation,the coins are partitioned into the desired number of *** division allows for efficient distribution of computational tasks across multiple *** simulation examples are conducted to compare the three solvers with serial programs,evaluating correctness,acceleration ratio,and parallel *** results reveal a relative error of approximately 0.3%in forming force among the parallel and serial solvers,while the predicted insufficient material zones align with experimental ***,speedup ratio and parallel efficiency are assessed for the coining process *** pureMPI parallel solver achieves a maximum acceleration of 9.5 on a single computer(utilizing 12 cores)and the hybrid solver exhibits a speedup ratio of 136 in a cluster(using 6 compute nodes and 12 cores per compute node),showing the strong scalability of the hybrid MPI/OpenMP programming *** approach effectively meets the simulation requirements for commemorative coins with intricate relief patterns.

关键词： Hybrid MPI/OpenMP parallel computing MPI OpenMP imprint forming

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A functionalized activated carbon adsorbent prepared from waste amidoxime resin by modifying with H_(3)PO_(4) and ZnCl_(2) and its excellent Cr(Ⅵ)adsorption

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International Journal of Minerals,Metallurgy and Materials 2024年第3期31卷 585-598页

作者： Chunlin He yun liu Mingwei Qi Zunzhang liu Yuezhou Wei Toyohisa Fujita Guifang Wang Shaojian Ma Wenchao Yang School of Resources Environment and MaterialsGuangxi UniversityNanning 530004China State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures Guangxi UniversityNanning 530004China School of Nuclear Science and Technology University of South ChinaHengyang 421000China School of Nuclear Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China Key Laboratory of New Low-carbon Green Chemical Technology Education Department of Guangxi Zhuang Autonomous RegionNanning 530004China

With the application of resins in various fields, numerous waste resins that are difficult to treat have been produced. The industrial wastewater containing Cr(Ⅵ) has severely polluted soil and groundwater environments, thereby endangering human health. Therefore, in this paper, a novel functionalized mesoporous adsorbent PPR-Z was synthesized from waste amidoxime resin for adsorbing Cr(Ⅵ). The waste amidoxime resin was first modified with H3PO4 and ZnCl_(2), and subsequently, it was carbonized through slow thermal decomposition. The static adsorption of PPR-Z conforms to the pseudo-second-order kinetic model and Langmuir isotherm, indicating that the Cr(Ⅵ) adsorption by PPR-Z is mostly chemical adsorption and exhibits single-layer adsorption. The saturated adsorption capacity of the adsorbent for Cr(Ⅵ) could reach 255.86 mg/g. The adsorbent could effectively reduce Cr(Ⅵ) to Cr(Ⅲ) and decrease the toxicity of Cr(Ⅵ) during adsorption. PPR-Z exhibited Cr(Ⅵ) selectivity in electroplating wastewater. The main mechanisms involved in the Cr(Ⅵ) adsorption are the chemical reduction of Cr(Ⅵ) into Cr(Ⅲ) and electrostatic and coordination interactions. Preparation of PPR-Z not only solves the problem of waste resin treatment but also effectively controls Cr(Ⅵ) pollution and realizes the concept of “treating waste with waste”.

关键词： waste amidoxime resin mesoporous adsorbent H_(3)PO_(4)and ZnCl_(2)processing Cr(VI)adsorption electroplating wastewater

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High-performance Si/VO_(2)-nanorod heterojunction photodetector based on photothermoelectric effect for detecting human radiation

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Rare Metals 2024年第3期43卷 1177-1185页

作者： Fu-Hai Guo Lan-Zhong Hao Wei-Zhuo Yu Si-Qi Li Guan-Chu liu Jing-Yi Hao yun-Jie liu College of Science China University of PetroleumQingdao266580China School of Materials Science and Engineering China University of PetroleumQingdao266580China

As a typical candidate of optoelectronic materials,vanadium dioxide(VO_(2))has wide applications in photodetectors(PDs),but is still challenging in largely enhancing the photodetecting performance for low-power human ***,high-performance Si/VO_(2)nanorods(NRs)heterojunction PDs based on the photothermoelectric(PTE)effect are *** uniform VO_(2)-NRs array films were deposited on Si by using magnetron sputtering technique,and a Si/VO_(2)heterojunctions were *** device exhibits a four-stage photoresponse and broadband photoresponse from ultraviolet to long-wavelength *** from the unique nanorods structure and the strong PTE effect,the fabricated device exhibits a large enhancement of the photodetecting performance,showing an ultrahigh photodetectivity of 1.6×10^(13)Jones and ultrafast response rates with a risingedge time of~65.0μs,three orders of magnitude higher than other VO_(2)-based ***,the device exhibits unique abilities to detect human radiation even when the human fingers are far away from the device surface up to 10.0 ***,the fabricated Si/VO_(2)devices can also be applied as breath sensors to distinguish different breathing *** results supply an effective route to design high-performance photodetectors toward detecting human thermal radiation and respiration.

关键词： Vanadium dioxide Heterojunction Photodetector Photothermoelectric Human radiation and respiration sensing

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