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Modeling and analysis for material removal and surface roughness in fluid jet polishing of optical glass

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Friction 2024年第7期12卷 1548-1563页

作者： Zhongchen cAO ming WANG Haitao LIU tian HUANG Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education Tianjin UniversityTianjin 300072China School of engineering The University of WarwickCoventry CV47ALUK

luid jet polishing(FJP)is a non-contact polishing technology that can fabricate free-form optical surfaces with sub-micron-level form accuracy and nano-level surface roughness,especially for hard and brittle *** surface generation model of FJP can be used to guide the determination and optimization of process parameters and is of great significance for understanding the evolution mechanism of surface ***,predictive models for the microscopic topography of polished surfaces are still *** study established a macroscopic surface profile model for predicting 3D material removal characteristics and surface texture by combining the 3D computer fluid dynamics(cFD)simulation model and single-particle erosion mechanism.A fractal theory-based erosion model has been built to calculate the material removal caused by the erosion of a single abrasive particle on the rough surface;thus,it predicts the micro-topography and surface roughness of the polished samples.A series of polishing experiments were conducted to analyze the feasibility and accuracy of the model quantitatively and study the influence mechanism of process parameters on the material removal characteristics and surface *** indicated that the models could well predict material removal and surface *** prediction accuracy of the surface roughness Ra and maximum removal depth is better than 91.6%and 90%,*** is also found that the material removal rate of FJP could reach 0.517 mm3/min,and the surface roughness convergence rate could reach 62.9%.

关键词： fluid jet polishing(FJP) computational fluid dynamics(cFD) material removal mechanism surface roughness theoretical model

Dopamine Switches Affective States Under Acute Sleep Deprivation

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Neuroscience Bulletin 2024年第8期40卷 1205-1208页

作者： Zhou-cai Luo tian-ming Gao State Key Laboratory of Organ Failure Research Key Laboratory of Mental Health of the Ministry of EducationGuangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired IntelligenceGuangdong-Hong Kong Joint Laboratory for Psychiatric DisordersGuangdong Province Key Laboratory of Psychiatric DisordersGuangdong Basic Research Center of Excellence for Integrated Traditional and Western Medicine for Qingzhi DiseasesDepartment of NeurobiologySchool of Basic Medical SciencesSouthern Medical UniversityGuangzhou 510515China

The transition of affective states manifests affective regulation,wherein individuals adaptively adjust their emotional states to cope with changes in the external environment,reflecting their sensitivity and adaptability to environmental *** process of affective state transition is complex,involving both instantaneous and persistent changes influenced by environmental,behavioral,and pharmacological *** underlying neural mechanisms encompass alterations in neurotransmitter release,neural circuit activity,and the plasticity of brain structures[1].

关键词： alterations Dopamine neural

Hollow Metal-Organic Framework/MXene/Nanocellulose composite Films for Giga/Terahertz Electromagnetic Shielding and Photothermal conversion

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Nano-Micro Letters 2024年第9期16卷 161-179页

作者： tian Mai Lei chen Pei‑Lin Wang Qi Liu ming‑Guo Ma Research center of Biomass clean Utilization MOE Engineering Research Center of Forestry Biomass Materials and BioenergyBeijing Key Laboratory of Lignocellulosic ChemistryCollege of Materials Science and TechnologyBeijing Forestry UniversityBeijing 100083People’s Republic of China State Silica-Based Materials Laboratory of Anhui Province Bengbu 233000People’s Republic of China

With the continuous advancement of communication technology,the escalating demand for electromagnetic shielding interference(EMI)materials with multifunctional and wideband EMI performance has become *** the electrical and magnetic components and designing the EMI material structure have attracted extensive interest,but remain a huge ***,we reported the alternating electromagnetic structure composite films composed of hollow metal-organic frameworks/layered MXene/nanocellulose(HMN)by alternating vacuum-assisted filtration *** HMN composite films exhibit excellent EMI shielding effectiveness performance in the GHz frequency(66.8 dB at Kaband)and THz frequency(114.6 dB at 0.1-4.0 THz).Besides,the HMN composite films also exhibit a high reflection loss of 39.7 dB at 0.7 THz with an effective absorption bandwidth up to 2.1 ***,HMN composite films show remarkable photothermal conversion performance,which can reach 104.6℃under 2.0 Sun and 235.4℃under 0.8 W cm^(−2),*** unique micro-and macrostructural design structures will absorb more incident electromagnetic waves via interfacial polarization/multiple scattering and produce more heat energy via the local surface plasmon resonance *** features make the HMN composite film a promising candidate for advanced EMI devices for future 6G communication and the protection of electronic equipment in cold environments.

关键词： Metal-organic frameworks MXene Nanocellulose Electromagnetic shielding Photothermal conversion

Facile Synthesis of Polyisothioureas via Alternating copolymerization of Aziridines and Isothiocayanates

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chinese Journal of Polymer Science 2024年第3期42卷 292-298,I0005页

作者： Hao-tian Zhang ming-Xin Niu Qi Zhang chen-Yang Hu Xuan Pang Key Laboratory of Polymer Ecomaterials Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China Department of Materials Science and engineering Jilin UniversityChangchun 130025China School of Applied chemistry and engineering University of Science and Technology of ChinaHefei 230026China

Isothiourea is an important class of sulfur-containing molecules showing unique catalytic and biological activities. As such,polyisothiourea is envisioned to be an interesting type of polymer that potentially exhibits a number of interesting properties. However, there is no access to synthesizing well-defined polyisothiourea, and currently isothiourea-containing polymers are mainly prepared by immobilizing onto other polymer's side chain. Herein, we report the first facile synthesis of polyisothioureas via alternating copolymerization of aziridines and isothiocayanates. Mediated by the catalytic system of phosphazene superbases/alcohol, a broad scope of aziridines and isothiocayanates could be transformed into polyisothioureas with adjustable substitutions(11 examples). The structures of obtained polyisothioureas were fully characterized with ^(1)H-NMR, ^(13)c-NMR, and ^(1)H-^(13)c HMBc NMR. Moreover, the polyisothioureas show tunable thermal properties depending on substitutions on the isothiourea linkages. The novel structure of these polyisothioureas will enable a powerful platform for the discovery of nextgeneration functional plastics.

关键词： Polyisothioureas Alternative copolymer Aziridines Isothiocayanates

Genetically modified non-human primate models for research on neurodegenerative diseases

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Zoological Research 2024年第2期45卷 263-274页

作者： ming-tian Pan Han Zhang Xiao-Jiang Li Xiang-Yu Guo Guangdong Key Laboratory of Non-human Primate Research Guangdong-Hongkong-Macao Institute of CNS RegenerationJinan UniversityGuangzhouGuangdong 510632China

Neurodegenerative diseases(NDs)are a group of debilitating neurological disorders that primarily affect elderly populations and include Alzheimer's disease(AD),Parkinson's disease(PD),Huntington's disease(HD),and amyotrophic lateral sclerosis(ALS).currently,there are no therapies available that can delay,stop,or reverse the pathological progression of NDs in clinical *** the population ages,NDs are imposing a huge burden on public health systems and affected *** models are important tools for preclinical investigations to understand disease pathogenesis and test potential *** numerous rodent models of NDs have been developed to enhance our understanding of disease mechanisms,the limited success of translating findings from animal models to clinical practice suggests that there is still a need to bridge this translation *** World nonhuman primates(NHPs),such as rhesus,cynomolgus,and vervet monkeys,are phylogenetically,physiologically,biochemically,and behaviorally most relevant to *** is particularly evident in the similarity of the structure and function of their central nervous systems,rendering such species uniquely valuable for neuroscience ***,the development of several genetically modified NHP models of NDs has successfully recapitulated key pathologies and revealed novel *** review focuses on the efficacy of NHPs in modeling NDs and the novel pathological insights gained,as well as the challenges associated with the generation of such models and the complexities involved in their subsequent analysis.

关键词： Neurodegeneration Non-human primate Macaque monkey Animal model Gene modification

Effect of Al content in molten steel on interaction between MgO-c refractory and SPHc steel

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Journal of Iron and Steel Research International 2024年第4期31卷 838-848页

作者： Fu-bin Gao Fu-ming Wang Xiang Zhang tian-yu Du Xin-hua Wangg School of Metallurgical and Ecological engineering University of Science and Technology BeijingBeijing 100083China Handan Iron and Steel company Hegang GroupHandan 056015HebeiChina The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina

The effect of Al content in molten steel on the interaction between SPHc steel(0.005-0.068 wt.%Al,and 19×10^(-4)-58×10^(-4)wt.%O)and MgO-c refractory(11.63 wt.%c)was ***-metallic inclusions in the steel were examined at various periods(0,5,15,30,45,and 60 min)as well as the MgO-c interface after 60 min of corrosion at 1600℃.The results show that when MgO-c refractory comes into contact with SPHc steel,the refractory interface consists of three layers arranged from the innermost to the outermost,including the original refractory layer,the dense MgO layer,and the iron infiltration *** carbon in the MgO-c refractories and the Al content in the molten steel undergo a reaction with the MgO in the refractories,resulting in an increase in Mg concentration in the *** Al content in the molten steel from 0.005 to 0.068 wt.%causes a spinel layer to appear at the interface,and the disappearance time of Al_(2)O_(3) inclusions in the steel decreases from 60 to 30 min,while the average MgO content in inclusions ***,controlling the Al content in the molten steel and the smelting duration can help regulate the formation of spinel inclusionsinthe steel.

关键词： MgO-c refractory SPHc steel Inclusion-Spinel Al-killed steel Interfacial reaction

Measurement and correlation of Liquid-liquid Equilibria for 1-Hexene-n-Hexane-3-Methysulfolane

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china Petroleum Processing & Petrochemical Technology 2024年第2期26卷 81-87页

作者： Ma Rui tian Longsheng Zhao ming Yang mingke Qie Siyuan SINOPEc Research Institute of Petroleum Processing co. Ltd.Beijing 100083China

Utilizing solvent extraction to separate alkanes and olefins from catalytic light gasoline is an effective method for maximizing the utility of gasoline *** study presents the determination of liquid-liquid equilibrium data for the ternary system of 1-hexene-n-hexane-3-methylsulfolane at 30℃,40℃,and 50℃under atmospheric *** obtained data facilitated the construction of a ternary phase diagram for the *** results showed that the extraction selectivity of 1-hexene/n-hexane exceeded 1.5 when using 3-methylsulfolane as the extraction ***,the thermodynamic consistency of the experimental data was examined using Hand’s equation and the Othmer-Tobias *** correlation coefficient,R^(2)≥0.9578,indicated the acceptable reliability of the phase equilibrium ***,the NRTL(non-random two liquid)model was used to correlate the liquid-liquid phase equilibrium data and derive the binary interaction ***,the results demonstrated that the root mean square deviation of the NRTL model correlation values from the experimental values did not exceed 2.5%.

关键词： liquid-liquid phase equilibrium 1-hexene n-hexane 3-methylsulfolane NRTL

The Orthogonal Bases of Exponential Functions Based on Moran-Sierpinski Measures

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Acta Mathematica Sinica,english Series 2024年第7期40卷 1804-1824页

作者： Qi Rong Deng Xing Gang HE ming tian LI Yuan Ling YE School of Mathematics and Statistics Center for Applied Mathematics of Fujian Province&Key Laboratory of Analytical Mathematics and Applications(Ministry of Education)Fujian Normal UniversityFuzhou350117P.R.China School of Mathematics and Statistics Key Lab NAA-MOE and Hubei Key Lab-Math.Sci.Central China Normal UniversityWuhan430079P.R.China School of Mathematical Sciences&South china Research center for Applied Mathematics and Interdisciplinary Studies South China Normal UniversityGuangzhou510631P.R.China

Let An∈M2(ℤ)be integral matrices such that the infinite convolution of Dirac measures with equal weightsμ{A_(n),n≥1}δA_(1)^(-1)D*δA_(1)^(-1)A_(2)^(-2)D*…is a probability measure with compact support,where D={(0,0)^(t),(1,0)^(t),(0,1)^(t)}is the Sierpinski *** prove that there exists a setΛ⊂ℝ2 such that the family{e2πi〈λ,x〉:λ∈Λ} is an orthonormal basis of L^(2)(μ{A_(n),n≥1})if and only if 1/3(1,-1)A_(n)∈Z^(2)for n≥2 under some metric conditions on A_(n).

关键词： Moran-Sierpinski measures orthonormal basis of exponential functions self-affine measures spectral measures

A survey on model-based reinforcement learning

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Science china(Information Sciences) 2024年第2期67卷 59-84页

作者： Fan-ming LUO tian XU Hang LAI Xiong-Hui cHEN Weinan ZHANG Yang YU National Key Laboratory for Novel Software Technology Nanjing University Polixir. ai Department of computer Science and engineering Shanghai Jiao Tong University

Reinforcement learning(RL) interacts with the environment to solve sequential decision-making problems via a trial-and-error approach. Errors are always undesirable in real-world applications, even though RL excels at playing complex video games that permit several trial-and-error attempts. To improve sample efficiency and thus reduce errors, model-based reinforcement learning(MBRL) is believed to be a promising direction, as it constructs environment models in which trial-and-errors can occur without incurring actual costs. In this survey, we investigate MBRL with a particular focus on the recent advancements in deep RL. There is a generalization error between the learned model of a non-tabular environment and the actual environment. consequently, it is crucial to analyze the disparity between policy training in the environment model and that in the actual environment, guiding algorithm design for improved model learning, model utilization, and policy training. In addition, we discuss the recent developments of model-based techniques in other forms of RL, such as offline RL, goal-conditioned RL, multi-agent RL, and meta-RL. Furthermore,we discuss the applicability and benefits of MBRL for real-world tasks. Finally, this survey concludes with a discussion of the promising future development prospects for MBRL. We believe that MBRL has great unrealized potential and benefits in real-world applications, and we hope this survey will encourage additional research on MBRL.

关键词： reinforcement learning model-based reinforcement learning planning model learning model learning with reduced error model usage