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Relationship between hydrogenation degree and pyrolysis performance of jet fuel

chinese Journal of Chemical Engineering 2024年第4期68卷 35-42页

作者： Qing liu Tinghao Jia lun Pan Jijun Zou Xiangwen Zhang Key Laboratory for Green Chemical and Technology School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China Haihe Laboratory of Sustainable Chemical Transformations Tianjin 300192China Zhejiang Institute of Tianjin University Ningbo 315201China Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology College of Chemical and Biological EngineeringZhejiang UniversityHangzhou 310027China

Understanding the relationship between the chemical composition and pyrolysis performance of endothermic hydrocarbon fuel(EHF) is of great significance for the design and optimization of advanced EHFs. In this work, the effect of deep hydrogenation on the pyrolysis of commercial RP-3 is *** with different hydrogenation degrees were obtained by the partially and completely catalytic hydrogenation and their pyrolysis performances were investigated using an apparatus equipped with an electrically heated tubular reactor. The results show that with the increase of hydrogenation degree, fuel conversion almost remains constant during the pyrolysis process(500-650°C, 4 MPa);however, the heat sink increases slightly, and the anti-coking performance significantly improves, which are highly related to their H/C ratios. Detailed characterisations reveal that the difference of the pyrolysis performance can be ascribed to the content of aromatics and cycloalkanes: the former are prone to initiate secondary reactions to form coking precursors, while the latter could act as the hydrogen donor and release hydrogen, which will terminate the radical propagation reactions and suppress the coke deposition. This work should provide the guidance for upgrading EHFs by modulating the composition of EHFs.

关键词： RP-3 Fuel Pyrolysis Hydrogenation Deposition

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Impact of Carbon Chain Structures in the Backbone on the Flexibility of Modified Polyarylene Sulfide Resins: Molecular Dynamics Simulations and Mesoscopic Analysis

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chinese Journal of Polymer Science 2024年第4期42卷 544-557页

作者： chi Zhang Rong liu Jing-Yuan liu Wen-Wei Jiang Key Laboratory of Fine Chemical Engineering and Functional Materials School of Chemical EngineeringSichuan UniversityChengdu610065China

In the domain of high-performance engineering polymers, the enhancement of mechanical flexibility in poly(phenylene sulfide) (PPS) resins has long posed a significant challenge. A novel molecular structure, designated as PP-He-IS, wherein imide rings and an aliphatic hexylene chain are covalently incorporated into the PPS backbone to enhance its flexibility, is introduced in this study. Molecular dynamics (MD) simulations are employed to systematically explore the effects of diversifying the backbone chain structures by substituting phenyl units with alkyl chains of varying lengths, referred to as PP-A-IS where “A” signifies the distinct intermediary alkyl chain configurations. Computational analyses reveal a discernable decrement in the glass transition temperature (Tg) and elastic modulus, counterbalanced by an increment in yield strength as the alkyl chain length is extended. Notably, the PP-He-IS variant is shown to exhibit superior yield strength while simultaneously maintaining reduced elastic modulus and Tg values, positioning it as an advantageous candidate for flexible PPS applications. Mesoscopic analyses further indicate that structures such as PP-He-IS, PP-Pe-IS, and PP-Bu-IS manifest remarkable flexibility, attributable to the presence of freely rotatable carbon-carbon single bonds. Experimental validation confirms that a melting temperature of 504 K which is lower than that of conventional PPS, and lower crystallinity are exhibited by PP-He-IS, thereby affording enhanced processability without compromising inherent thermal stability. Novel insights into the strategic modification of PPS for mechanical flexibility are thus furnished by this study, which also accentuates the pivotal role played by molecular dynamics simulations in spearheading high-throughput investigations in polymer material modifications.

关键词： Molecular dynamics simulations Polyarylene Sulfide Main-chain modifications Flexibility Aliphatic hexylene chain

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Optimal Shape Factor and Fictitious Radius in the MQ-RBF:Solving Ill-Posed Laplacian Problems

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Computer Modeling in Engineering & Sciences 2024年第6期139卷 3189-3208页

作者： Chein-Shan liu Chung-lun Kuo chih-Wen Chang Center of Excellence for Ocean Engineering Taiwan Ocean UniversityKeelung202301TaiwanChina Department of Mechanical Engineering National United UniversityMiaoli36063TaiwanChina

To solve the Laplacian problems,we adopt a meshless method with the multiquadric radial basis function(MQRBF)as a basis whose center is distributed inside a circle with a fictitious radius.A maximal projection technique is developed to identify the optimal shape factor and fictitious radius by minimizing a merit function.A sample function is interpolated by theMQ-RBF to provide a trial coefficient vector to compute the merit *** can quickly determine the optimal values of the parameters within a preferred rage using the golden section search *** novel method provides the optimal values of parameters and,hence,an optimal MQ-RBF;the performance of the method is validated in numerical ***,nonharmonic problems are transformed to the Poisson equation endowed with a homogeneous boundary condition;this can overcome the problem of these problems being *** optimal MQ-RBF is extremely *** further propose a novel optimal polynomial method to solve the nonharmonic problems,which achieves high precision up to an order of 10^(−11).

关键词： Laplace equation nonharmonic boundary value problem Ill-posed problem maximal projection optimal shape factor and fictitious radius optimal MQ-RBF optimal polynomial method

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Honeycomb-like biochar framework coupled with Fe_(3)O_(4)/FeS nanoparticles as efficient heterogeneous Fenton catalyst for phenol degradation

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Journal of Environmental Sciences 2024年第2期136卷 390-399页

作者： Aihua Cheng Yi He Xiaohe liu chi He Department of Environmental Engineering College of Geology and EnvironmentXi’an University of Science and TechnologyXi’an 710054China State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power EngineeringXi’an Jiaotong UniversityXi’an 710049China National Engineering Laboratory for VOCs Pollution Control Material and Technology University of Chinese Academy of SciencesBeijing 101408China

Achieving an efficient and stable heterogeneous Fenton reaction over a wide pH range is of great significance for wastewater ***,a pollen-derived biochar catalyst with a unique honeycomb-like structure,coupled with the dispersion of magnetic Fe_(3)O_(4)/FeS(Fe/S)nanoparticles,was synthesized by simple impregnation precursor,followed by *** prepared Fe/S-biochar catalyst demonstrated outstanding phenol degradation efficiency across a wide pH range,with 98%of which eliminated even under neutral conditions(pH 7.0).The high catalytic activity was due to the multilevel porous structure of pollenderived biochar provided enough active sites and allowed for better electron transfer,then increases oxidation ability to promote the ***,the acid microenvironment formed by SO_(4)^(2-)group from Fe/S composite extended the pH range for Fenton reaction,and S^(2-)facilitated the conversion of≡Fe^(3+)to≡Fe^(2+),resulting in remarkable degradation ***,biochar can effectively promote cycling stability by limiting Fe *** work may provide a general strategy for designing 3D framework biochar-based Fe/S catalysts with excellent performance for heterogeneous Fenton reactions.

关键词： Biomass Biochar Fenton reaction Fe_(3)O_(4)/FeS(Fe/S) Phenol degradation

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An impact sensitivity assessment method of spacecraft based on virtual exterior wall

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Defence Technology（防务技术） 2024年第1期31卷 142-157页

作者： Runqiang chi Yuyan liu Diqi Hu Baojun Pang Hypervelocity Impact Research Center Harbin Institute Of TechnologyHarbin150080China

The impact sensitivity assessment of spacecraft is to obtain the probability of spacecraft encountering the OD/M(orbital debris or meteoroid),which is a prerequisite for survivability assessment of on-orbit *** impact sensitivity assessment method of spacecraft based on virtual exterior wall was proposed to improve the computational *** method eliminates determination of the outermost surface elements of the spacecraft before generating the debris rays,which are assumed to originate from a non-concave virtual wall that completely wraps the *** Dist Mesh method was adopted for the generating of the virtual wall to ensure its mesh *** influences of the sizes,mesh densities,shapes of the virtual wall on the efficiency and accuracy were considered to obtain the best combination of the size and mesh density of the wall and *** results of this method were compared with those of S3DE(Survivability of Spacecraft in Space Debris Environment),BUMPER,MDPANTO,ESABASE2/Debris to verify the feasibility of the *** PchiP(Piecewise Cubic Hermite Interpolating Polynomial)was used to fit the size *** relationship of the space debris to acquire the impact probability of OD/M with arbitrary size on the spacecraft.

关键词： Sensitivity OD/M Spacecraft Virtual exterior wall

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Optimized scheduling of integrated energy systems for low carbon economy considering carbon transaction costs

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Global Energy Interconnection 2024年第4期7卷 377-390页

作者： Chao liu Weiru Wang Jing Li Xinyuan liu Yongning chi china Electric Power Research Institute Beijing 100192P.R.China State Grid Shanxi Electric Power Research Institute Taiyuan 030001P.R.China

With the introduction of the“dual carbon”goal and the continuous promotion of low-carbon development,the integrated energy system(IES)has gradually become an effective way to save energy and reduce *** study proposes a low-carbon economic optimization scheduling model for an IES that considers carbon trading *** the goal of minimizing the total operating cost of the IES and considering the transferable and curtailable characteristics of the electric and thermal flexible loads,an optimal scheduling model of the IES that considers the cost of carbon trading and flexible loads on the user side was *** role of flexible loads in improving the economy of an energy system was investigated using examples,and the rationality and effectiveness of the study were verified through a comparative analysis of different *** results showed that the total cost of the system in different scenarios was reduced by 18.04%,9.1%,3.35%,and 7.03%,respectively,whereas the total carbon emissions of the system were reduced by 65.28%,20.63%,3.85%,and 18.03%,respectively,when the carbon trading cost and demand-side flexible electric and thermal load responses were considered *** electrical and thermal loads did not have the same impact on the system *** the analyzed case,the total cost and carbon emissions of the system when only the flexible electrical load response was considered were lower than those when only the flexible thermal load response was taken into *** have an excess of carbon trading credits and can profit from selling them,whereas other devices have an excess of carbon trading and need to buy carbon credits.

关键词： Demand response Combined cooling Heating and power system Carbon transaction costs Flexible electric and thermal loads Optimal scheduling

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Adaptive Observer-Based Finite-Time Fault Tolerant Control for Non-Strict Feedback Systems

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Journal of Systems Science & Complexity 2024年第4期37卷 1526-1544页

作者： SHENG Ning liu Yang chi Ronghu AI Zidong College of Automation and Electronic Engineering Qingdao University of Science and TechnologyQingdao 266042China

This paper considers the adaptive finite-time control and observer design method for a class of non-strict feedback systems with unmeasurable states,unknown nonlinear dynamics and actuator *** this paper,an observer is proposed to estimate the unmeasurable states in finite-time based on adaptive technique and neural networks,while the actuator faults are not *** filter is used to solve the computational explosion and singularity problems caused by the traditional backstepping and non-strict feedback structure,*** the fault efficiency indicators in real systems are not available,two-layer neural networks are adopted,where the first network is to estimate the unknown nonlinearities of systems and the second one is to estimate fault efficiency indicators and unknown nonlinear *** proposed scheme guarantees that states are bounded through stability ***,two experiments including a numerical example and a spring-mass-damper system are given to verify the effectiveness of the proposed method.

关键词： Command filter fault tolerant control finite-time control non-strict systems two-layer neural networks

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A hybrid memory architecture supporting fine-grained data migration

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Frontiers of Computer Science 2024年第2期18卷 31-41页

作者： Ye chi Jianhui YUE Xiaofei LIAO Haikun liu Hai JIN National Engineering Research Center for Big Data Technology and System Services Computing Technology and System LabCluster and Grid Computing LabSchool of Computer Science and TechnologyHuazhong University of Science and TechnologyWuhan 430074China Department of Computer Science Michigan Technological UniversityMichigan 49931USA

Hybrid memory systems composed of dynamic random access memory(DRAM)and Non-volatile memory(NVM)often exploit page migration technologies to fully take the advantages of different memory *** previous proposals usually migrate data at a granularity of 4 KB pages,and thus waste memory bandwidth and DRAM *** this paper,we propose Mocha,a non-hierarchical architecture that organizes DRAM and NVM in a flat address space physically,but manages them in a cache/memory *** the commercial NVM device-Intel Optane DC Persistent Memory Modules(DCPMM)actually access the physical media at a granularity of 256 bytes(an Optane block),we manage the DRAM cache at the 256-byte size to adapt to this feature of *** design not only enables fine-grained data migration and management for the DRAM cache,but also avoids write amplification for Intel Optane *** also create an Indirect Address Cache(IAC)in Hybrid Memory Controller(HMC)and propose a reverse address mapping table in the DRAM to speed up address translation and cache ***,we exploit a utility-based caching mechanism to filter cold blocks in the NVM,and further improve the efficiency of the DRAM *** implement Mocha in an architectural *** results show that Mocha can improve application performance by 8.2%on average(up to 24.6%),reduce 6.9%energy consumption and 25.9%data migration traffic on average,compared with a typical hybrid memory architecture-HSCC.

关键词： non-volatile memory hybrid memory system data migration fine-grained caching

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Photoinduced transposed Paternò-Büchi reaction for effective synthesis of high-performance jet fuel

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chinese Journal of Chemical Engineering 2024年第3期67卷 39-48页

作者： Jinxiu Hu Xianlong liu Yi liu Kang Xue Chengxiang Shi Xiangwen Zhang Li Wang Ji-Jun Zou lun Pan Key Laboratory for Green Chemical Technology of the Ministry of Education School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China Haihe Laboratory of Sustainable Chemical Transformations Tianjin 300192China Zhejiang Institute of Tianjin University Ningbo 315201China Collaborative Innovative Center of Chemical Science and Engineering(Tianjin) Tianjin 300072China

High-energy-density fuels are important for volume-limited aerospace vehicles,but the increase in fuel energy density always leads to poor cryogenic ***,we investigated the transposed Paternò-Büchi reaction of biomass cyclic ketone and cyclic alkene to synthesize a new kind of alkyl-substituted polycyclic hydrocarbon fuel with high energy density and good cryogenic *** triplet-energy-quenching results and phosphorescent emission spectra reveal the sensitization mechanism of the reaction,including photosensitizer excitation,triplettriplet energy transfer,cyclization,and relaxation,and the possible reaction path was revealed by the density functional theory(DFT)*** reaction conditions of photosensitizer type and addition,molar ratio of substrates,reaction temperature,and incident light intensity were optimized,with the target product yield achieving 65.5%.Moreover,the reaction dynamics of the reaction rate versus the light intensity are *** the hydrogenation-deoxygenation reaction,three fuels with a high density of 0.864-0.938 g·ml^(-1) and a low freezing point of<-55℃ are *** work provides a benign and effective approach to synthesize high-performance fuels.

关键词： High-energy-density fuel Transposed Patern-oeBüchi reaction Kinetics Bioenergy Photochemistry

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Highly Accurate Golden Section Search Algorithms and Fictitious Time Integration Method for Solving Nonlinear Eigenvalue Problems

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Computer Modeling in Engineering & Sciences 2024年第5期139卷 1317-1335页

作者： Chein-Shan liu Jian-Hung Shen Chung-lun Kuo Yung-Wei Chen Center of Excellence for Ocean Engineering Taiwan Ocean UniversityKeelung202301TaiwanChina Department of Marine Engineering Taiwan Ocean UniversityKeelung202301TaiwanChina

This study sets up two new merit functions,which are minimized for the detection of real eigenvalue and complex eigenvalue to address nonlinear eigenvalue *** each eigen-parameter the vector variable is solved from a nonhomogeneous linear system obtained by reducing the number of eigen-equation one less,where one of the nonzero components of the eigenvector is normalized to the unit and moves the column containing that component to the right-hand side as a nonzero input vector.1D and 2D golden section search algorithms are employed to minimize the merit functions to locate real and complex ***,the real and complex eigenvectors can be computed very accurately.A simpler approach to the nonlinear eigenvalue problems is proposed,which implements a normalization condition for the uniqueness of the eigenvector into the eigenequation *** real eigenvalues can be computed by the fictitious time integration method(FTIM),which saves computational costs compared to the one-dimensional golden section search algorithm(1D GSSA).The simpler method is also combined with the Newton iterationmethod,which is convergent very *** the proposed methods are easily programmed to compute the eigenvalue and eigenvector with high accuracy and efficiency.

关键词： Nonlinear eigenvalue problem quadratic eigenvalue problem two new merit functions golden section search algorithm fictitious time integration method

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