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A Formal Model for Analyzing Fair Exchange Protocols Based on Event Logic

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Computer Modeling in Engineering & Sciences 2024年第3期138卷 2641-2663页

作者： ke Yang Meihua Xiao Zehuan li School of Electrical Engineering and Automation East China Jiaotong UniversityNanchang330013China School of Software East China Jiaotong UniversityNanchang330013China

Fair exchange protocols play a critical role in enabling two distrustful entities to conduct electronic data exchanges in a fair and secure *** protocols are widely used in electronic payment systems and electronic contract signing,ensuring the reliability and security of network *** order to address the limitations of current research methods and enhance the analytical capabilities for fair exchange protocols,this paper proposes a formal model for analyzing such *** proposed model begins with a thorough analysis of fair exchange protocols,followed by the formal definition of *** definition accurately captures the inherent requirements of fair exchange *** upon event logic,the model incorporates the time factor into predicates and introduces knowledge set *** enhancement empowers the improved logic to effectively describe the state and knowledge of protocol participants at different time points,facilitating reasoning about their acquired *** maximize the intruder’s capabilities,channel errors are translated into the behaviors of the *** participants are further categorized into honest participants and malicious participants,enabling a comprehensive evaluation of the intruder’s potential *** employing a typical fair exchange protocol as an illustrative example,this paper demonstrates the detailed steps of utilizing the proposed model for protocol *** entire process of protocol execution under attack scenarios is presented,shedding light on the underlying reasons for the attacks and proposing corresponding *** developedmodel enhances the ability to reason about and evaluate the security properties of fair exchange protocols,thereby contributing to the advancement of secure network transactions.

关键词： Fair exchange protocols fairness formal analysis logic reasoning

A cyclic behavior of CME accelerations for accelerating and decelerating events

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Research in Astronomy and Astrophysics 2009年第10期9卷 1165-1172页

作者： Peng-Xin Gao ke-jun li National Astronomical Observatories / Yunnan Observatory Chinese Academy of Sciences Kunming 650011 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

We investigate the cyclic evolutionary behavior of CME accelerations for accelerating and decelerating CME events in cycle 23 from 1997 January to 2007 December. It is found that the absolute values of semiannual mean accelerations of both accelerating and decelerating CME events roughly wax and wane in a cycle, delaying the sunspot cycle in time phase. We also investigate the semiannual number of CMEs with positive and neg- ative acceleration and find that there are more decelerating CME events than accelerating CME events during the maximum period of a cycle （about three years）, but there are more accelerating CME events than decelerating CME events during the rest of the time interval of the cycle. Our results seem to suggest that the different driving mechanisms may be acting accelerate and decelerate CME events; for accelerating CME events, the propelling force （Fp） statistically seems to play a significant role in pushing CMEs outward; for decelerating CME events, the drag （Fd） statistically seems to play a more effective role in determining CME kinematic evolution in the outer corona. During the maximum period of a cycle, because of the V^2 dependence, Fd is generally stronger; because of the magnetic field dependence, Fp is also generally stronger. Thus, the absolute values of both the negative and positive accelerations are generally larger during that time. Because of the V^2 dependence, Fd may be more effective during the maximum period of a cycle. Hence, there are more decelerating CME events than accelerating CME events during that time. During the minimum time interval of a cycle, CMEs have relatively small speeds, and Fp may be more effective. Therefore, there are more accelerating CME events than decelerating CME events during that time.

关键词： Sun corona -- Sun coronal mass ejections (CMEs)

Cerium oxide inclusion nucleation mechanism based on classical nucleation theory and two-step nucleation

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Journal of Rare Earths 2024年第4期42卷 793-802页

作者： Yutang li jun Wang linzhu Wang Chaoyi Chen Shufeng Yang junqi li Xiang li School of Materials and Metallurgy Guizhou UniversityGuiyang550025China State key Laboratory of Public Big Data Guizhou UniversityGuiyang550025China School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing100083China Department of Materials&Metallurgy Engineering Guizhou Institute of TechnologyGuiyang550003China

It is challenging to assess the mechanism responsible for the nucleation of inclusions in metals at high *** present work therefore systematically investigates the nucleation of cerium oxide inclusions according to classical nucleation theory and a two-step nucleation *** nucleation rates and nucleation radii of these inclusions are obtained,and the results demonstrate a considerable difference between theoretical and experimental *** the basis of a two-step nucleation mechanism,(CeO_(2))_(n) and(Ce_(2)O_(3))_(n)(n=1-6)clusters were constructed and the thermodynamic properties of both these clusters and of cerium oxide nanoparticles were *** addition,the entropies and heat capacity changes of cerium oxides were determined using first principles calculations and are found to be consistent with literature *** present data indicate that the cerium oxide inclusion nucleation pathway can be summarized as[Ce]+[O]→(CeO_(2))n/(Ce_(2)O_(3))_(n)→(Ce_(2)O_(3))_(n)→(Ce_(2)O_(3))_(2)→core(Ce_(2)O_(3)crystal)-shell((Ce_(2)O_(3))_(2) cluster)nanoparticles→(Ce_(2)O_(3))bulk.

关键词： Cerium oxide inclusion Classical nucleation theory Two-step nucleation mechanism First principles Rare earths

Heterobimetallic lanthanide tetrahedral cages:Synthesis,design and application for potential multimodal imaging contrast agent

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Journal of Rare Earths 2024年第2期42卷 278-285,I0002页

作者： Yongxiu li Feng Guo Siwei Wei Duofu li jun Zhang Kai Xu Dongping li Department of Chemistry Nanchang UniversityNanchang330031China key Laboratory of Functional Molecule Design and Interface Process Anhui Jianzhu UniversityHefei230601China Department of Otolaryngology Head and Neck SurgeryThe Second Affiliated Hospital of Nanchang UniversityNanchang330006China

The construction and functionalization of lanthanide-organic cages have been a research hotspot in coordination *** from the unique luminescent and magnetic properties of lanthanide ions,the potential applications of lanthanide-organic cages in biological imaging applications are promising,but only a few corresponding explorations have been *** rein,we introduced a series of lanthanide tetrahedral cages,(Eu_(n)Gd_(4-n)L_(4))(sol)_8(n=0,1,2,3 and 4,where L=(4,4',4"-tris(4,4,4-trifluoro-1,3-dioxobutyl)-triphenylamine,and sol=dimethyl sulfoxide and methanol),with potential applications in biological *** the good luminescent and magnetic properties of Eu^(3+) and Gd^(3+) ions,Eu_(4)L_(4) and Gd_(4)L_(4) complexes show a high luminescence quantum yield of 29% in DMSO and large longitudinal relaxivity(r_(1)) of 11.4(mmol/L)^(-1)/s at 0.5 T in water containing 1 vol% DMSO,*** heterobimetallic Eu-Gd complexes achieve a dual imaging mode by combining luminescent and magnetic centers in one *** the Gd:Eu ratio increases from 1:3 to 3:1,the r_(1) values increases from 5.33 to 8.64(mmoI/L)^(-1)/s,higher than that of commercial contrast agent Gd-DOTA(3.23(mmol/L)^(-1)/s).Owing to their low toxicity and good cell imaging ability toward ECA 109 cells,the selfassembled Eu-Gd heterobimetallic tetrahedral cages could be potential candidates for the multimodal imaging contrast agent.

关键词： Lanthanide organic cage Luminescence Cell imaging Contrast agents Rare earths

Projecting Wintertime Newly Formed Arctic Sea Ice through Weighting CMIP6 Model Performance and Independence

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Advances in Atmospheric Sciences 2024年第8期41卷 1465-1482页

作者： Jiazhen ZHAO Shengping HE ke FAN Huijun WANG Fei li key Laboratory of Meteorological Disaster Ministry of Education/Joint International Research Laboratory of Climate and Environment Change(ILCEC)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD)Nanjing University of Information Science&TechnologyNanjing 210044China Geophysical Institute University of Bergen and Bjerknes Centre for Climate ResearchBergen 5007Norway School of Atmospheric Science Sun Yat-sen Universityand Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)Zhuhai 519082China Nansen Environmental and Remote Sensing Center and Bjerknes Centre for Climate Research Bergen 5007Norway Nansen-Zhu International Research Center Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519082China

Precipitous Arctic sea-ice decline and the corresponding increase in Arctic open-water areas in summer months give more space for sea-ice growth in the subsequent cold seasons. Compared to the decline of the entire Arctic multiyear sea ice,changes in newly formed sea ice indicate more thermodynamic and dynamic information on Arctic atmosphere–ocean–ice interaction and northern mid–high latitude atmospheric teleconnections. Here, we use a large multimodel ensemble from phase 6 of the Coupled Model Intercomparison Project(CMIP6) to investigate future changes in wintertime newly formed Arctic sea ice. The commonly used model-democracy approach that gives equal weight to each model essentially assumes that all models are independent and equally plausible, which contradicts with the fact that there are large interdependencies in the ensemble and discrepancies in models' performances in reproducing observations. Therefore, instead of using the arithmetic mean of well-performing models or all available models for projections like in previous studies, we employ a newly developed model weighting scheme that weights all models in the ensemble with consideration of their performance and independence to provide more reliable projections. Model democracy leads to evident bias and large intermodel spread in CMIP6 projections of newly formed Arctic sea ice. However, we show that both the bias and the intermodel spread can be effectively reduced by the weighting scheme. Projections from the weighted models indicate that wintertime newly formed Arctic sea ice is likely to increase dramatically until the middle of this century regardless of the emissions ***, it may decrease(or remain stable) if the Arctic warming crosses a threshold(or is extensively constrained).

关键词： wintertime newly formed Arctic sea ice model democracy model weighting scheme model performance model independence

Effect of proppant sizes and injection modes on proppant transportation and distribution in the tortuous fracture model

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Particuology 2024年第1期84卷 261-280页

作者： jun li Xu Han Siyuan He Mingyi Wu Xin Huang Nianyin li State key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu610500China Chongqing Industry Polytechnic College Chongqing401120China Sichuan Particles Energy and Technology Co. LtdChengdu611630China Engineering Technology Research Institute of PetroChina Southwest Oil and Gas Field Company Chengdu610017China

Particle-fluid transport and placement mechanism in tortuous fracture played a crucial role in uncon-ventional ***,most studies focused on mono-size proppant with fluid transport pro-cesses in tortuous ***,the mixture-size proppant with fluid movement mechanism in tortuous fracture was still ***,this study designed and applied a series of experiments with a physical analog model of a tortuous fracture with 120°and 90°-angled bends and combined high-speed camera-based *** experimental system was used to track different-mixture-sized proppant particle motion trajectories for a series of proppant injection schemes;The following conclu-sions were drawn from this study:*** pile-up processes mechanism in all investigated schemes were similar and could be reduced to four main *** packing structure at both sides of the fracture wall had different variation rates,which were controlled by the mix ratio(change from 1∶1-1∶5)of proppant *** new packing patterns,such as Zebra Stripe,had occurred,controlled by the different proppant injection ***-sized mono-proppant(30/50 mesh)had the highest transport efficiency in the tortuous fracture,followed by the mixed-sized multi-proppant(10/20 mesh:30/50 mesh),large-sized proppant(10/20 mesh)was the *** optimized alternating in-jection mode was recommended as injecting small-sized proppant first(30/50 mesh)and followed by mixed-sized multi-proppant(10/20 mesh:30/50 mesh),which could contribute to obtaining the optimal both proppant packing height and travel distance in tortuous *** correlations were devel-oped for predicting the proppant packing height and transportation distance.

关键词： Tortuous fracture model Mixed-sized proppant Multi-sized proppant injection mode Proppant motion and distribution Packing mechanism

Observation of ballistic-diffusive thermal transport in GaN transistors using thermoreflectance thermal imaging

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Rare Metals 2024年第1期43卷 389-394页

作者： Zhi-ke liu Yang Shen Han-ling li Bing-Yang Cao key Laboratory for Thermal Science and Power Engineering of Ministry of Education Department of Engineering MechanicsTsinghua UniversityBeijing 100084China

To develop effective thermal management strategies for gallium-nitride (GaN) transistors, it is essential to accurately predict the device junction temperature. Since the width of the heat generation in the devices is comparable to phonon mean free paths (MFPs) of GaN, phonon ballistic transport exists and can significantly affect the heat transport process.

关键词： temperature. transistors GaN

Interface strengthening for thermal sprayed WC-10Co4Cr coating subjected to pulsed magnetic treatment

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Rare Metals 2024年第2期43卷 780-795页

作者： Cheng-Kai Qian Qu liu Heng Wang ke-Jian li Zhi-Peng Cai Department of Mechanical Engineering Tsinghua UniversityBeijing100084China Tianjin Research Institute for Advanced Equipment Tsinghua UniversityTianjin300304China State key Laboratory of Tribology in Advanced Equipment Tsinghua UniversityBeijing100084China

The reliability of the coated industry components demands ideal fatigue properties of the coating,and it is mainly determined by the performance of the *** this study,pulsed magnetic treatment(PMT)was applied to the thermal sprayed WC-10Co4Cr coating,and the fatigue lifetime of the coated bolt increased by 219.82%under an imitation of the operating mode *** tests further proved that both the adhesion and cohesion strength were improved after PMT,and they benefit from the interface strengthening *** formation of coherent WC/Co interfaces was characterized by in-situ transmission electron microscopy(TEM),and the molecular dynamic simulations indicate that the work of separation of these interfaces is much higher than the original disordered *** stress was relaxed and distributed more homogeneously after PMT,and it mainly contributes to the coating/substrate *** work provides a new post-treatment method focusing on the interfaces in the WC-based coating and gives insight into its mechanism so that it is hopeful to be applied to other kinds of coatings.

关键词： Cemented carbide coating Pulsed magnetic treatment Interface strengthening Fatigue properties Adhesion strength

DepthGAN: GAN-based depth generation from semantic layouts

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Computational Visual Media 2024年第3期10卷 505-522页

作者： Yidi li jun Xiao Yiqun Wang Zhengda Lu School of Artiﬁcial Intelligence University of Chinese Academy of SciencesBeijingChina College of Computer Science Chongqing UniversityChongqingChina

Existing GAN-based generative methodsare typically used for semantic image synthesis. Wepose the question of whether GAN-based architecturescan generate plausible depth maps and ﬁnd thatexisting methods have difficulty in generating depthmaps which reasonably represent 3D scene structuredue to the lack of global geometric ***, we propose DepthGAN, a novel method ofgenerating a depth map using a semantic layout asinput to aid construction, and manipulation of wellstructured 3D scene point clouds. Speciﬁcally, weﬁrst build a feature generation model with a cascadeof semantically-aware transformer blocks to obtaindepth features with global structural *** our semantically aware transformer block, wepropose a mixed attention module and a semanticallyaware layer normalization module to better exploitsemantic consistency for depth features ***, we present a novel semantically weighteddepth synthesis module, which generates adaptivedepth intervals for the current scene. We generate theﬁnal depth map by using a weighted combination ofsemantically aware depth weights for different depthranges. In this manner, we obtain a more accuratedepth map. Extensive experiments on indoor andoutdoor datasets demonstrate that DepthGAN achievessuperior results both quantitatively and visually for thedepth generation task.

关键词： depth map generation generative model transformer scene generation