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Micro segment analysis of supercritical methane thermal-hydraulic performance and pseudo-boiling in a PCHE straight channel

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Petroleum Science 2024年第2期21卷 1275-1289页

作者： Qian li Zi-Jie lin liu Yang yue Wang yue li Wei-Hua Cai Laboratory of Thermo-Fluid Science and Nuclear Engineering Northeast Electric Power UniversityJilin132000JilinChina School of Energy and Power Engineering Northeast Electric Power UniversityJilin132000JilinChina

The printed circuit heat exchanger(PCHE) is receiving wide attention as a new kind of compact heat exchanger and is considered as a promising vaporizer in the LNG process. In this paper, a PCHE straight channel in the length of 500 mm is established, with a semicircular cross section in a diameter of 1.2 *** simulation is employed to investigate the flow and heat transfer performance of supercritical methane in the channel. The pseudo-boiling theory is adopted and the liquid-like, two-phase-like, and vapor-like regimes are divided for supercritical methane to analyze the heat transfer and flow *** results are presented in micro segment to show the local convective heat transfer coefficient and pressure drop. It shows that the convective heat transfer coefficient in segments along the channel has a significant peak feature near the pseudo-critical point and a heat transfer deterioration when the average fluid temperature in the segment is higher than the pseudo-critical point. The reason is explained with the generation of vapor-like film near the channel wall that the peak feature related to a nucleateboiling-like state and heat transfer deterioration related to a film-boiling-like state. The effects of parameters, including mass flow rate, pressure, and wall heat flux on flow and heat transfer were *** calculating of the averaged heat transfer coefficient of the whole channel, the traditional method shows significant deviation and the micro segment weighted average method is adopted. The pressure drop can mainly be affected by the mass flux and pressure and little affected by the wall heat flux. The peak of the convective heat transfer coefficient can only form at high mass flux, low wall heat flux, and near critical pressure, in which condition the nucleate-boiling-like state is easier to appear. Moreover,heat transfer deterioration will always appear, since the supercritical flow will finally develop into a filmboiling-like state. So hea

关键词： Printed circuit heat exchanger Vaporization Supercritical methane Pseudo-boiling Micro segment analysis

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Variable Selection for Generalized linear Model with Highly Correlated Covariates

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Acta Mathematica Sinica,English Series 2024年第6期40卷 1458-1480页

作者： li li yue Wei Tao WANG Gao Rong li School of Statistics and Data Science Nanjing Audit UniversityNanjing 211815P.R.China School of Mathematics Statistics and MechanicsBeijing University of TechnologyBeijing 100124P.R.China School of Statistics Beijing Normal UniversityBeijing 100875P.R.China

The penalized variable selection methods are often used to select the relevant covariates and estimate the unknown regression coefficients simultaneously,but these existing methods may fail to be consistent for the setting with highly correlated *** this paper,the semi-standard partial covariance(SPAC)method with Lasso penalty is proposed to study the generalized linear model with highly correlated covariates,and the consistencies of the estimation and variable selection are shown in high-dimensional settings under some regularity *** simulation studies and an analysis of colon tumor dataset are carried out to show that the proposed method performs better in addressing highly correlated problem than the traditional penalized variable selection methods.

关键词： Generalized linear model highly correlated covariates Lasso penalty semi-standard partial covariance variable selection

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An Interpretable light Attention-Convolution-Gate Recurrent Unit Architecture for the Highly Accurate Modeling of Actual Chemical Dynamic Processes

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Engineering 2024年第8期39卷 104-116页

作者： yue li Ning li Jingzheng Ren Weifeng Shen School of Chemistry and Chemical Engineering Chongqing UniversityChongqing 400044China Chongqing Key Laboratory of Catalysis and New Environmental Materials School of Environment and ResourcesChongqing Technology and Business UniversityChongqing 400067China Department of Industrial and Systems Engineering The Hong Kong Polytechnic UniversityHong Kong 999077China

To equip data-driven dynamic chemical process models with strong interpretability,we develop a light attention–convolution–gate recurrent unit(LACG)architecture with three sub-modules—a basic module,a brand-new light attention module,and a residue module—that are specially designed to learn the general dynamic behavior,transient disturbances,and other input factors of chemical processes,*** with a hyperparameter optimization framework,Optuna,the effectiveness of the proposed LACG is tested by distributed control system data-driven modeling experiments on the discharge flowrate of an actual deethanization *** LACG model provides significant advantages in prediction accuracy and model generalization compared with other models,including the feedforward neural network,convolution neural network,long short-term memory(LSTM),and ***,compared with the simulation results of a deethanization model built using Aspen Plus Dynamics V12.1,the LACG parameters are demonstrated to be interpretable,and more details on the variable interactions can be observed from the model parameters in comparison with the traditional interpretable model *** contribution enriches interpretable machine learning knowledge and provides a reliable method with high accuracy for actual chemical process modeling,paving a route to intelligent manufacturing.

关键词： Interpretable machine learning light attention-convolution-gate recurrent unit architecture Process knowledge discovery Data-driven process model Intelligent manufacturing

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Electricity Pricing with Continuous-time Commodity Model and Non-monotonic Load Curve

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 272-280页

作者： lijia Han yue li Haoyong Chen Ningning Lu Mathematical and Physical Science School North China Electric Power UniversityBeijing 102206China School of Electric Power Engineering South China University of TechnologyGuangzhou 510641China

Under the "carbon peak and carbon neutrality"background,clean energy enters the market on a large scale,so it is very important to study the pricing theory of *** bright spot of this paper is that the load curve is more *** the original version of electricity pricing theory based on continuous time commodity model,the load curve is supposed to be a monotonic function with time for simplicity of derivation,which is not *** overcome this defect,load curves are supposed to be in shapes of a unimodal model and multimodal cases in this paper,which are more in conformity with the actual load curve in real-world power *** study cases are used to demonstrate the rationality of the proposed *** results together with the authors'previous work provide a complete pricing scheme for continuous-time electricity commodity model.

关键词： Functional optimization market equilibrium spot pricing variational method

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Phosphine/Benzocyclone-based Neutral Nickel Catalysts for Ethylene Polymerization and Copolymerization with Polar Monomers

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Chinese Journal of Polymer Science 2024年第2期42卷 202-212,I0007页

作者： Fei Wang li Pan Vladislav A.Tuskaev Svetlana Ch.Gagieva yue-Sheng li Tianjin Key Lab of Composite&Functional Materials School of Material Science and EngineeringTianjin UniversityTianjin300072China Department of Chemistry Lomonosov Moscow State UniversityRussian Federation InstitutionLeninskie Gory 1Moscow119991Russian Federation A N Nesmeyanov Institute of Organoelement Compounds Russian Academy of SciencesVavilova st.28Moscow119991Russian Federation

The efficient copolymerization of olefin with polar monomers using nickel-based catalysts presents a longstanding challenge. In this contribution, three phosphine-benzocyclone ligands and corresponding neutral nickel catalysts(Ni1: Ar = Ph;Ni2: Ar = 2-(C_(6)H_(5))C_(6)H_(4);Ni3: Ar = 2-[2',6'-(Me O)_(2)-C_(6)H3]C_(6)H_(4)) were prepared and applied for the ethylene polymerization and copolymerization with polar monomers without any cocatalyst. The bulky substituent groups in complexes Ni2 and Ni3 contributed to high catalytic activities(up to 7.24×10^(6) and 9.04×10^(6)g·mol Ni^(-1)·h^(-1), respectively), and produced high-molecular-weight polyethylene(Mw up to 545.7 k Da). Complex Ni3 exhibited high activities for ethylene polymerization at the level of 10^(6) g·mol Ni^(-1)·h^(-1) across a wide range from 30 ℃ to 120 ℃, exhibiting excellent high temperature tolerance. These nickel complexes were also effectively employed in the copolymerization of ethylene with methyl acrylate, ethyl acrylate, butyl acrylate and lauryl acrylate, producing copolymers with high molecular weights(Mw up to 80.5 k Da) and high polar monomer incorporation(up to 8.2 mol%). Microstructure analyses revealed that the introduction of large sterically hindered substituents facilitated the incorporation of polar functional units into the polymer backbone. This study demonstrates the potential of these nickel-based catalysts for efficient copolymerization of olefin with polar monomers.

关键词： Neutral nickel catalyst Ethylene polymerization Copolymerization Polar acrylate monomers

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Leaching behavior and microstructure of phosphorus in converter slag

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Journal of Iron and Steel Research International 2024年第7期31卷 1646-1660页

作者： Chao-gang Zhou Jin-yue li Qing-gong Chen Yin-ye Yang Wei Gong li-qun Ai Shu-huan Wang Bei-yue Ma College of Metallurgy and Energy North China University of Science and TechnologyTangshan 063210HebeiChina Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education Wuhan University of Science and TechnologyWuhan 430081HubeiChina College of Materials Science and Engineering Guizhou Minzu UniversityGuiyang 550025GuizhouChina School of Materials and Architectural Engineering Guizhou Normal UniversityGuiyang 550025GuizhouChina School of Metallurgy Northeastern UniversityShenyang 110819LiaoningChina

Converter slag is a by-product of the steelmaking process and contains a large amount of Ca,Fe,P and other *** the phosphorus in the converter slag can be effectively extracted,the resulting phosphorus can be used as a phosphate *** in converter slag is mainly enriched in 2CaO·SiO_(2)-3CaO·P_(2)O_(5)(C_(2)S-C_(3)P)solid solution and is easily dissolved in ***,acid leaching method was used to dissolve the solid solution to extract phosphorus in converter slag,so as to realize the recycling of phosphorus resources in converter *** leaching behavior of three actual converter slags from different steel mills in acid leaching solutions composed of citric acid,sodium hydroxide,hydrochloric acid and deionized water was studied by X-ray diffraction,scanning electron microscopy combined with energy dispersive spectrometry,Fourier transform infrared spectroscopy and Raman spectroscopy to reveal the change in object image structure as well as SiO_(4) and PO_(4) tetrahedron before and after acid *** results show that only a small amount of phosphorus in converter slag with too low basicity is enriched in C_(2)S-C_(3)P solid solution,resulting in poor leaching *** the converter slag has a high basicity,the removal effect of phosphorus is 70.64%-81.88%.In addition,when the basicity of converter slag is roughly the same,the dephosphorization effect of slag with high FeO content is relatively *** acid leaching will cause depolymerization behavior of SiO_(4) and PO_(4) tetrahedron,so that the mole fraction of Q0(Si)(asymmetric stretching vibration of Si-O bond in SiO_(4) tetrahedron with bridge oxygen number of 0)and NBO/Si(non-bridging oxygen in silicate tetrahedra)will ***-containing solids can be obtained from the solution after acid leaching through static precipitation,and the solids have the potential to make phosphate fertilizers.

关键词： Dephosphorization converter slag Acid leaching Phosphorus Solid solution Slag structure

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Latest assessment methods for mitochondrial homeostasis in cognitive diseases

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Neural Regeneration Research 2024年第4期19卷 754-768页

作者： Wei You yue li Kaixi liu Xinning Mi Yitong li Xiangyang Guo Zhengqian li Department of Anesthesiology Peking University Third Hospital Peking University Third Clinical Medical College Beijing Center of Quality Control and Improvement on Clinical Anesthesia Anesthesia and Perioperative Medicine Branch of China International Exchange and Promotive Association for Medical and Health Care(CPAM)

Mitochondria play an essential role in neural function,such as supporting normal energy metabolism,regulating reactive oxygen species,buffering physiological calcium loads,and maintaining the balance of morphology,subcellular distribution,and overall health through mitochondrial *** the recent technological advances in the assessment of mitochondrial structure and functions,mitochondrial dysfunction has been regarded as the early and key pathophysiological mechanism of cognitive disorders such as Alzheimer’s disease,Parkinson’s disease,Huntington’s disease,mild cognitive impairment,and postoperative cognitive *** review will focus on the recent advances in mitochondrial medicine and research methodology in the field of cognitive sciences,from the perspectives of energy metabolism,oxidative stress,calcium homeostasis,and mitochondrial dynamics(including fission-fusion,transport,and mitophagy).

关键词： cognitive disorders mitochondrial dysfunction mitochondrial energy metabolism mitochondrial dynamics mitochondrial transport mitophagy mitochondrial biogenesis oxidative stress calcium homeostasis

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Design and construction of size-controlled CoO/CS catalysts for Fischer–Tropsch synthesis

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Nano Research 2024年第4期17卷 2520-2527页

作者： Wei Sun Ting Kuang Guiyou Wei yue li Yaqin liu Shuai Lyu Yuhua Zhang Jinlin li li Wang Key Laboratory of Catalysis and Energy Materials Chemistry of Ministry of Education&Hubei Key Laboratory of Catalysis and Materials Science South-Central Minzu UniversityWuhan 430074China Hubei Key Laboratory of Biomass Fibers and Eco-dyeing&Finishing College of Chemistry and Chemical EngineeringWuhan Textile UniversityWuhan 430200China

The use of supported Co-based catalysts is widespread in various catalytic reactions due to their unique *** structural sensitivity of these catalysts is closely linked to their particle size and crystal ***,comprehending the structure–activity relationship requires the development of well-defined Co-based ***,we employed a colloidal wet chemical process and a heterogeneous nucleation method to prepare well-defined Co-based catalysts supported by inert carbon *** nanospheres’surface possesses abundant functional groups that efficiently capture metal complexes and facilitate the nucleation and growth of CoO *** adjusting the Co source concentration,solvent molar ratio,and nucleation growth kinetics,we successfully prepared CoO/carbon sphere(CS)catalysts with different particle sizes and crystal *** influence of metallic face-centered cubic(fcc)-Co^(0) particle size in the range of 6.6–17.6 nm on the performance of Fischer–Tropsch synthesis(FTS)using well-defined CoO/CS catalysts has been *** result demonstrated that the turnover frequency(TOF)remained constant for CoO/CS catalysts with metallic fcc-Co^(0) particle size larger than 7.7 ***,both the selectivity and the activity changed for CoO/CS catalysts with smaller particles(lic fcc-Co^(0) particle size was reduced from 17.6 to 7.7 nm,the cobalt time yield increased to 6.7μmolCO·gCo^(-1)·s^(-1),indicating improved catalytic *** the same time,the CH_(4) selectivity decreased to 4.9%,suggesting a higher preference for hydrocarbon *** findings demonstrate the importance of particle size in Co catalyzed Fischer–Tropsch *** use of well-defined CoO/CS catalysts offers valuable insights into the structure–activity relationship,leading to a better understanding of Co catalyzed Fischer–Tropsch synthesis.

关键词： Fischer–Tropsch synthesis(FTS) cobalt size effects phase effects carbon nanospheres

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Effects of combustion temperature on the optical properties of brown carbon from biomass burning

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Journal of Environmental Sciences 2024年第3期137卷 302-309页

作者： Peng Gao Rule Deng Song Jia yue li Xuefei Wang Qian Xing School of Chemistry Sciences University of Chinese Academy of SciencesBeijing 100049China College of Chemistry and Materials Engineering Beijing Technology and Business UniversityBeijing 100048China

Biomass burning has been known as one of main sources of Brown Carbon(BrC)in *** this study,by controlling the combustion temperature at 250℃,350℃,and 450℃,the methanol soluble organic carbon(MSOC)and methanol insoluble carbon(MISC)from pine wood burning was collected by ***–Vis,excitation emission matrix(EEM),TEM and FTIR spectra were applied to investigate the properties of BrC *** MSOC at 250℃ and 350℃,all the spectral profiles of UV–Vis absorption and excitation emission matrix are almost the same,while the EEM of MSOC at 450℃ are different from that of the other *** MISC fuorescence was observed only in the case of 450℃.In the FTIR spectra,with the temperature increasing the peaks associated to the oxygen-contained functions was weakened,indicating the formation of the fuorophores with larger conjugated system,especially aromatic *** results show that biomass combustion at low temperature produces more oxygen-riched BrC,which possesses relatively lower light absorption,while at high temperature produces more aromatics hydrocarbons with relatively strong light *** results of this work are helpful to trace the source of brown carbon and optimize biomass energy utilization.

关键词： Biomass burning Combustion temperature Methanol-soluble brown carbon EEM Impinger

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Ultrathin Zincophilic Interphase Regulated Electric Double Layer Enabling Highly Stable Aqueous Zinc‑Ion Batteries

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Nano-Micro Letters 2024年第5期16卷 285-299页

作者： Yimei Chen Zhiping Deng Yongxiang Sun yue li Hao Zhang Ge li Hongbo Zeng Xiaolei Wang Department of Chemical and Materials Engineering University of Alberta9211‑116 Street NWEdmontonAB T6G 1H9Canada Department of Mechanical Engineering University of Alberta9211‑116 Street NWEdmontonAB T6G 1H9Canada

The practical application of aqueous zinc-ion batteries for large-grid scale systems is still hindered by uncontrolled zinc dendrite and side *** the elec-trical double layer via the electrode/electrolyte interface layer is an effective strategy to improve the stability of Zn ***,we report an ultrathin zincophilic ZnS layer as a model *** a given cycling current,the cell with Zn@ZnS electrode displays a lower potential drop over the Helmholtz layer(stern layer)and a suppressed diffuse layer,indicating the regulated charge distribution and decreased electric double layer repulsion *** zinc adsorption sites are also expected as proved by the enhanced electric double-layer ***,the symmetric cell with the ZnS protection layer can stably cycle for around 3,000 h at 1 mA cm^(-2) with a lower overpotential of 25 *** coupled with an I2/AC cathode,the cell demonstrates a high rate performance of 160 mAh g^(-1) at 0.1 A g^(-1) and long cycling stability of over 10,000 cycles at 10 A g^(-1).The Zn||MnO_(2) also sustains both high capacity and long cycling stability of 130 mAh g^(-1) after 1,200 cycles at 0.5 A g^(-1).

关键词： Zinc anode Electric double-layer regulation Multifunction SEI layer Inhibited side reactions and dendrite Rapid kinetics

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