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CONVERGENCE OF MODIFIED TRUNCATED EULER-MARUYAMA METHOD FOR STOCHASTIC DIFFERENTIAL EQUATIONS WITH HOLDER DIFFUSION COEFFICIENTS

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Journal of Computational Mathematics 2024年第4期42卷 1109-1123页

作者： Guangqiang Lan yu jiang College of Mathematics and Physics Beijing University of Chemical TechnologyBeijing 100029China

Convergence of modified truncated Euler-Maruyama(MTEM)method for stochastic differential equations(SDEs)with(1/2+α)-Holder continuous diffusion coefficients are investigated in this *** prove that the MTEM method for... 详细信息

关键词： Stochastic differential equations Modified truncated Euler-Maruyama method Strong convergence One-sided Lipschitz Holder continuous

Growth of Ag/g-C_(3)N_(4) nanocomposites on nickel foam to enhance photocatalytic degradation of formaldehyde under visible light

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Journal of Environmental Sciences 2024年第3期137卷 432-442页

作者： Ze Wang Zhi Huang jiang yu Xiao Shao Weidong Peng Jie yu Yinying jiang Department of Environmental Science and Engineering College of Architecture and EnvironmentSichuan UniversityChengdu 610065China Institute of New Energy and Low Carbon Technology Sichuan UniversityChengdu 610065China School of Agriculture and Environment University of Western AustraliaPerth 6907Western AustraliaAustralia Yibin Institute of Industrial Technology Sichuan UniversityYibin 644000China

Formaldehyde is a pollutant that significantly affects the indoor air ***,conventional remediation approaches can be challenging to deal with low-concentration formaldehyde in an indoor *** this study,Photocatalysts of Ag/graphitic carbon nitride(g-C_(3)N_(4))/Ni with 3D reticulated coral structure were prepared by thermal polymerization and liquid phase photo-deposition,using nickel foam(NF)as the *** demonstrated that when the Ag concentration was 3%,and the relative humidity was 60%,the Ni/Ag/g-C_(3)N_(4)showed the maximum degradation rate of formaldehyde at 90.19%under visible light irradiation,and the formaldehyde concentration after degradation was lower than the Hygienic standard stated by the Chinese *** porous structure of Ni/Ag/g-C_(3)N_(4)and the formation of Schottky junctions promoted the Adsorption efficiency and degradation of formaldehyde,while the nickel foam carrier effectively promoted the desorption of degradation ***,the degradation rate was only reduced by3.4%after 16 recycles,the three-dimensional porous structure extended the lifetime of the *** study provides a new strategy for the degradation of indoor formaldehyde at low concentrations.

关键词： Graphitic carbon nitride(g-C_(3)N_(4)) Nickel foam(NF) Ag Formaldehyde Photocatalysis

Physical neural networks with self-learning capabilities

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Science China(Physics,Mechanics & Astronomy) 2024年第8期67卷 23-42页

作者： Weichao yu Hangwen Guo jiang Xiao Jian Shen State Key Laboratory of Surface Physics and Institute for Nanoelectronic Devices and Quantum Computing Fudan UniversityShanghai 200433China Zhangjiang Fudan International Innovation Center Fudan UniversityShanghai 201210China Department of Physics Fudan UniversityShanghai 200433China Shanghai Research Center for Quantum Sciences Shanghai 201315China Collaborative Innovation Center of Advanced Microstructures Nanjing 210093China

Physical neural networks are artificial neural networks that mimic synapses and neurons using physical systems or *** networks harness the distinctive characteristics of physical systems to carry out computations effectively,potentially surpassing the constraints of conventional digital neural networks.A recent advancement known as“physical self-learning”aims to achieve learning through intrinsic physical processes rather than relying on external *** article offers a comprehensive review of the progress made in implementing physical self-learning across various physical *** learning strategies that contribute to the realization of physical self-learning are *** challenges in understanding the fundamental mechanism of learning,this work highlights the progress towards constructing intelligent hardware from the ground up,incorporating embedded self-organizing and self-adaptive dynamics in physical systems.

关键词： self-learning physical neural networks neuromorphic computing physical learning

Reliability analysis of carbon fiber rod-reinforced umbilical cable under tension using an improved sampling method

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Petroleum Science 2024年第4期21卷 2769-2778页

作者： yu Zhang Hong-yu Zhang Ran Xia Si-Ao jiang Fang Wang College of Safety and Ocean Engineering China University of Petroleum China Academy of Aerospace Aerodynamics China Aerospace Science and Technology Group College of Engineering Science and Technology Shanghai Ocean University

The umbilical cable is a vital component of subsea production systems that provide power, chemical agents, control signals et al., and its requirement for reliability is exceedingly high. However, as the umbilical cable is a composite structure comprising multiple functional units, the reliability analysis of such cables involves numerous parameters that can impact calculation efficiency. In this paper, the reliability analysis of a new kind of umbilical cable with carbon fiber rod under tension is analyzed. The global dynamic analytical model is first established to determine the maximum tension load, then the local analytical model of umbilical cable including each unit are constructed by finite element method(FEM). Based on the mechanical analytical model, the reliability of umbilical cable under tension load is studied using response surface method(RSM) and Monte Carlo method. During the calculation process, a new tangent plane sampling method to calculate the response surface function(RSF) is proposed in this paper, which could make sampling points faster come close to the RSF curve, and it is proved that the calculation efficiency increases about 33% comparing with traditional method.

关键词： Umbilical cable Carbon fiber rod Failure analysis Response surface method Reliability

Response of ocean acidification to atmospheric carbon dioxide removal

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Journal of Environmental Sciences 2024年第6期140卷 79-90页

作者： Jiu jiang Long Cao Xiaoyu Jin Zechen yu Han Zhang Jianjie Fu Guibin jiang School of Environment Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou 310024China State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China Key Laboratory of Geoscience Big Data and Deep Resources of Zhejiang Province School of Earth SciencesZhejiang UniversityHangzhou 310058China Zhejiang Climate Center Hangzhou 310052China

Artificial CO_(2)removal from the atmosphere(also referred to as negative CO_(2)emissions)has been proposed as a potential means to counteract anthropogenic climate *** we use an Earth system model to examine the response of ocean acidification to idealized atmospheric CO_(2)removal *** our simulations,atmospheric CO_(2)is assumed to increase at a rate of 1%per year to four times its pre-industrial value and then decreases to the pre-industrial level at a rate of 0.5%,1%,2%per year,*** results show that the annual mean state of surface ocean carbonate chemistry fields including hydrogen ion concentration([H^(+)]),pH and aragonite saturation state respond quickly to removal of atmospheric CO_(2).However,the change of seasonal cycle in carbonate chemistry lags behind the decline in atmospheric CO_(2).When CO_(2)returns to the pre-industrial level,over some parts of the ocean,relative to the pre-industrial state,the seasonal amplitude of carbonate chemistry fields is substantially *** results also show that changes in deep ocean carbonate chemistry substantially lag behind atmospheric CO_(2)*** CO_(2)returns to its pre-industrial value,the whole-ocean acidity measured by[H^(+)]is 15%-18%larger than the pre-industrial level,depending on the rate of CO_(2)*** study demonstrates that even if atmospheric CO_(2)can be lowered in the future as a result of net negative CO_(2)emissions,the recovery of some aspects of ocean acidification would take decades to centuries,which would have important implications for the resilience of marine ecosystems.

关键词： Carbon dioxide removal Net negative CO_(2)emission Ocean acidification Climate change Earth system modeling

Committed-programming reductions: formalizations,implications and relations

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Science China(Information Sciences) 2024年第10期67卷 151-171页

作者： jiang ZHANG yu yu Dengguo FENG Shuqin FAN Zhenfeng ZHANG State Key Laboratory of Cryptology Department of Computer Science and Engineering Shanghai Jiao Tong University Trusted Computing and Information Assurance Laboratory Institute of SoftwareChinese Academy of Sciences

In this work, we introduce a class of black-box(BB) reductions called committed-programming reduction(CPRed) in the random oracle model(ROM) and obtain the following interesting results:(1) we demonstrate that some well-known schemes, including the full-domain hash(FDH) signature(Eurocrypt1996) and the Boneh-Franklin identity-based encryption(IBE) scheme(Crypto 2001), are provably secure under CPReds;(2) we prove that a CPRed associated with an instance-extraction algorithm implies a reduction in the quantum ROM(QROM). This unifies several recent results, including the security of the Gentry-Peikert-Vaikuntanathan IBE scheme by Zhandry(Crypto 2012) and the key encapsulation mechanism(KEM) variants using the Fujisaki-Okamoto transform by jiang et al.(Crypto 2018) in the ***, we show that CPReds are incomparable to non-programming reductions(NPReds) and randomly-programming reductions(RPReds) formalized by Fischlin et al.(Asiacrypt 2010).

关键词： provable security random oracle model quantum random oracle model black-box reduction/separation programmability

Investigation on the vortical structures by the Liutex method in turbulent channels at Re_(τ)=180 with scalloped and triangular riblet control

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Journal of Hydrodynamics 2024年第1期36卷 35-52页

作者： Zhang-dan yu Shang jiang Hai-dong yu Bi-yu Pang Xin Dong Yi-qian Wang School of Mathematical Sciences Soochow UniversitySuzhou215006China Beijing Institute of Astronautical System Engineering Beijing100076China

Riblets are a series of small protrusions formed along the flow direction,which have been extensively studied as a passive turbulent drag reduction *** and numerical simulations have shown that well-designed riblets can significantly reduce drag in turbulent flows,making them highly promising and valuable for various *** this study,we focus on a scalloped riblet,which is designed by smoothly connecting two third-order polynomials,and thus the sharpness of the tip and the curvature of the valley can be well *** conduct direct numerical simulations of turbulent channel with smooth plate,scalloped riblet-mounted and triangular riblet-mounted *** in wall units of W^(+)=20 and height-width ratio ofγ=0.5 are selected for both riblet *** with the smooth plate case,the scalloped riblet case achieves an 8.68%drag reduction,while the triangular riblet case achieves a 4.79%drag *** obtained drag reduction rate of the triangular riblet is consistent with previous experiments and simulations,and the results indicate that the scalloped riblet is more effective in reducing drag and deserves further *** compare turbulent statistics of the scalloped riblet case with those of the triangular riblet *** mean velocity profiles of riblets are similar,but both the Reynolds shear stress and second-order statistics of velocity fluctuations and Liutex are significantly reduced in the scalloped riblets controlled turbulent channel,indicating that the scalloped riblet can more effectively suppress the spanwise and wall-normal turbulent intensity near the *** also compare the pre-multiplied spectra of streamwise velocity and streamwise Liutex component for the three cases to investigate the energy distribution and characteristics of Liutex *** Liutex vortex identification method is also utilized to analyze the instantaneous flow field,which provides insights into the flow field and could be bene

关键词： Liutex vector riblet drag reduction tip sharpness turbulent channel scalloped

In situ crosslink polymerization induced long-lived multicolor supramolecular hydrogel based on modifiedβ-cyclodextrin

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Chinese Chemical Letters 2024年第2期35卷 374-379页

作者： Yonghui Sun Linnan jiang Yong Chen yu Liu College of Chemistry State Key Laboratory of Elemento-Organic Chemistry Nankai UniversityTianjin 300071China

The construction of hydrogels with good mechanical properties and phosphorescent properties is full of ***,we report a supramolecular phosphorescent hydrogel with long lifetime,high tensile strength and self-healing property,which can be easily constructed through in-situ thermalinitiated polymerization of isocyanatoethyl acrylate-modifiedβ-cyclodextrin(β-CD-DA)and acrylatemodified adamantane(Ad-DA),acrylic acid(AA),followed by the non-covalent association with carbon dots(CNDs).The lifetime of phosphorescent hydrogel can reach 1261 ms at room temperature,and the quantum yield is 11%.Importantly,through the efficient triplet to singlet Förster resonance energy transfer(TS-FRET),the phosphorescent hydrogel shows the good phosphorescence energy transfer property for organic dyes Rhodamine B and Eosin Y with the delayed fluorescence lifetime up to 730 ms and 585 ms as well as the energy transfer efficiency(Φ_(ET))up to 99.9%and 99.3%,***,owing to the host-guest interactions betweenβ-CD-DA and Ad-DA,the three-dimensional cross-linked network phosphorescent hydrogel can be easily stretched to 18 times of its original length,and can achieve self-healing of the cut surfaces within 30 *** results will expand the scope of phosphorescent materials and provide new ideas and opportunities for materials science.

关键词： Room temperature phosphorescence Hydrogel Phosphorescence energy transfer Cyclodextrin Supramolecular interaction

Primordial black holes and curvature perturbations from false vacuum islands

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Science China(Physics,Mechanics & Astronomy) 2024年第9期67卷 58-72页

作者： Rong-Gen Cai yu-Shi Hao Shao-jiang Wang School of Physical Science and Technology Ningbo UniversityNingbo 315211China CAS Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China Asia Pacific Center for Theoretical Physics Pohang 37673Republic of Korea

Recently,much attention has been focused on the false vacuum islands that are flooded by an expanding ocean of true-vacuum bubbles slightly later than most of the other parts of the *** delayed decay regions will accumulate locally larger vacuum energy density by staying in the false vacuum longer than those already transited into the true vacuum.A false vacuum island with thus acquired density contrast of a super-horizon size will evolve locally from radiation dominance to vacuum dominance,creating a local baby Universe that can be regarded effectively as a local closed *** such density contrasts of super-horizon sizes can ever grow large enough to exceed the threshold of gravitational collapse,primordial black holes will form similar to those collapsing curvature perturbations on super-horizon scales induced by small-scale enhancements during *** not,such density contrasts can still induce curvature perturbations potentially observable *** this paper,we revisit and elaborate on the generations of primordial black holes and curvature perturbations from delayed-decayed false vacuum islands during asynchronous first-order phase transitions with fitting formulas convenient for future model-independent studies.

关键词： first-order phase transitions primordial black holes curvature perturbations