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Classification and spectrum optimization method of grease based on infrared spectrum

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Friction 2024年第6期12卷 1154-1164页

作者： Xin FENG Yanqiu xia Peiyuan XIE xiaohe LI School of Energy Power and Mechanical Engineering North China Electric Power UniversityBeijing 102206China State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China

The infrared(IR)absorption spectral data of 63 kinds of lubricating greases containing six different types of thickeners were obtained using the IR *** Kohonen neural network algorithm was used to identify the type of the lubricating *** results show that this machine learning method can effectively eliminate the interference fringes in the IR spectrum,and complete the feature selection and dimensionality reduction of the high-dimensional spectral *** 63 kinds of greases exhibit spatial clustering under certain IR spectrum recognition spectral bands,which are linked to characteristic peaks of lubricating greases and improve the recognition accuracy of these *** model achieved recognition accuracy of 100.00%,96.08%,94.87%,100.00%,and 87.50%for polyurea grease,calcium sulfonate composite grease,aluminum(Al)-based grease,bentonite grease,and lithium-based grease,*** on the different IR absorption spectrum bands produced by each kind of lubricating grease,the three-dimensional spatial distribution map of the lubricating grease drawn also verifies the accuracy of classification while recognizing the *** paper demonstrates fast recognition speed and high accuracy,proving that the Kohonen neural network algorithm has an efficient recognition ability for identifying the types of the lubricating grease.

关键词： grease infrared(IR)spectroscopy layered Kohonen network species recognition spectrum band optimization

Promotion effects of salt-alkali on ammonia volatilization in a coastal soil

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Pedosphere 2024年第1期34卷 191-199页

作者： Zhenqi SHI Dongli SHE Yongchun PAN Yongqiu xia College of Agricultural Science and Engineering Hohai UniversityNanjing 210098China Jiangsu Province Engineering Research Center for Agricultural Soil-Water Efficient Utilization Carbon Sequestration and Emission ReductionNanjing 210098China Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China

Coastal ecosystems are highly susceptible to salt-related problems due to their formation process and geographical location. As such ecosystems are the most accessible land resources on Earth, clarifying and quantifying the effects of salt-alkali conditions on N concentration and ammonia(NH_(3)) volatilization are pivotal for promoting coastal agricultural productivity. The challenge in establishing this effect is to determine how salt-alkali conditions impact NH_(3) volatilization through direct or indirect interactions. An incubation experiment using a coastal soil from a paddy farmland, combined with the structural equation modeling(SEM) method, was conducted to reveal the net effects of salt-alkali on NH_(3) volatilization and the role of environmental and microbial factors in mutual interaction networks. The specific experimental design consisted of four salt treatments(S1, S2, S3, and S4: 1‰, 3‰, 8‰, and 15‰ NaCl by mass of soil, respectively), four alkaline treatments(A1, A2, A3, and A4: 0.5‰, 1‰, 3‰, and 8‰ NaHCO_(3)by mass of soil, respectively) and a control without NaCl or NaHCO_(3) addition(CK), and each treatment had three urea concentrations(N1, N2, and N3: 0.05, 0.10, and 0.15 g N kg^(-1) soil,respectively) and three replicates. At the N1, N2, and N3 levels, NH_(3)volatilization increased by 9.31%–34.98%, 3.07%–26.92%, and 2.99%–43.61% as the NaCl concentration increased from 1‰ to 15‰, respectively, compared with CK. With an increase in the NaHCO_(3)concentration from 0.5‰ to 8‰, NH_(3) volatilization increased by 8.36%–56.46%, 5.49%–30.10%, and 30.72%–73.18% at the N1, N2, and N3 levels, respectively, compared with CK. According to the SEM method, salinity and alkalinity had positive direct effects on NH_(3)volatilization, with standardized path coefficients of 0.40 and 0.19, *** the total effects(net positive and negative effects) in the SEM results, alkalinity had a greater influence than salinity(total standardized coefficien

关键词： alkalinity coastal ecosystem NH_(3)emission N-transforming microbe salinity structural equation modeling

Unified method for typical gear failure modeling and stiffness calculation based on the matrix equation

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Frontiers of Mechanical Engineering 2024年第3期19卷 93-114页

作者： Fanshan MENG Xin ZHANG Heng xia Jiaxu WANG School of Mechanical Engineering Southwest Jiaotong UniversityChengdu 610031China State Key Laboratory of Mechanical Transmissions for Advanced Equipment Chongqing UniversityChongqing 400044China

The failure types in gear systems vary,with typical ones mainly including pitting,cracking,wear,and broken *** modeling and stiffness calculation methods have been developed for various gear failure types.A unified method for typical gear failure modeling and stiffness calculation is introduced in this study by considering the deviations in the time-varying meshing stiffness(TVMS)of faulty gears resulting from the use of different ***,a gear tooth is discretized into a large number of microelements expressed with a matrix,and unified models of typical gear failures are built by adjusting the values of the matrix *** values and positions of the microelements in the tooth failure model matrix have the same physical meaning as the parameter variables in the potential energy method(PEM),so the matrix-based failure model can be perfectly matched with ***,a unified method for TVMS is *** of healthy and faulty gears with pitting,wear,crack,and broken tooth is performed with the matrix equation,and the corresponding TVMS values are calculated by incorporating the matrix models with *** the basis of the results,the mechanism of typical fault types that affect TVMS is analyzed,and the conclusions are verified through the finite element *** developed unified method is a promising technique for studying the dynamic response characteristics of gear systems with different failure types because of its superiority in eliminating stiffness deviations.

关键词： gears matrix equation failure modeling TVMS calculation unified method

A NEW GLOBAL OPTIMIZATION ALGORITHM FOR MIXED-INTEGER QUADRATICALLY CONSTRAINED QUADRATIC FRACTIONAL PROGRAMMING PROBLEM

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Journal of Computational Mathematics 2024年第3期42卷 784-813页

作者： Bo Zhang Yuelin Gao xia Liu xiaoli Huang School of Civil and Hydraulic Engineering School of Mathematics and StatisticsNingxia UniversityYinchuan 750021China School of Mathematics and Information Science North Minzu UniversityYinchuan 750021China Ningxia Province Key Laboratory of Intelligent Information and Data Processing Yinchuan 750021China School of Mathematics and Statistics Ningxia UniversityYinchuan 750021China

The mixed-integer quadratically constrained quadratic fractional programming(MIQCQFP)problem often appears in various fields such as engineering practice,management science and network ***,most of the solutions to such problems are often designed for their unique *** paper puts forward a new global optimization algorithm for solving the problem *** first convert the MIQCQFP into an equivalent generalized bilinear fractional programming(EIGBFP)problem with integer ***,we linearly underestimate and linearly overestimate the quadratic functions in the numerator and the denominator respectively,and then give a linear fractional relaxation technique for EIGBFP on the basis of non-negative *** that,combining rectangular adjustment-segmentation technique and midpointsampling strategy with the branch-and-bound procedure,an efficient algorithm for solving MIQCQFP globally is ***,a series of test problems are given to illustrate the effectiveness,feasibility and other performance of this algorithm.

关键词： Global optimization Branch and bound Quadratic fractional programming Mixed integer programming

Immobilizing Triphenylamine with Photoredox Inert Sr^(2+)Forming Sr-MOF with Controlled Electron Migration for Photocatalytic Oxidation of Thiols to Disulfides

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Chinese Journal of Chemistry 2024年第10期42卷 1093-1099页

作者： Ying-xia Wang Fang Zheng Dong-xia Song Bao-Yue Niu Lu-Qian Deng xian-Ming Zhang Key Laboratory of Magnetic Molecules and Magnetic Information Materials(Ministry of Education) Schoolof Chemistry and Materials ScienceShanxi Normal UniversityTaiyuanShanxi 030006China Key Laboratory of Interface Science and Engineering in Advanced Material(Ministry of Education) College of ChemistryTaiyuan University of TechnologyTaiyuanShanxi 030024China

The photocatalytic oxidative coupling of thiols is one of the most popular methods to synthesize the *** and its derivatives(TPAs)are promising for the above reaction,but suffer from the easy polymerization and difficult *** overcome these obstacles while controlling the photogenerated electrons transfer directly to target substrates,herein,we constructed one TPA-based metal-organic framework(MOF),(Me_(2)NH_(2))[Sr(TCBPA)]·DMA·3H_(2)O(1),by direct self-assembly of tris(4′-carboxybiphenyl)amine(H_(3)TCBPA)and photoredox inert strontium ion(Sr^(2+)).DFT calculations revealed that the valence band maximum(VBM)and the conduction band minimum(CBM)are mainly located on TCBPA^(3-),successfully inhibiting the undesirable electron migration to metal *** results indicated that 1 displays superior performance than homogeneous H_(3)TCBPA,which may result from the abundant π…π and C—H…π interactions between the well-arranged TCBPA^(3-)and the build-in electric field between the anionic framework and the Me_(2)NH^(2+).This work highlights that immobilizing TPAs into MOFs is one promising approach to designing heterogeneous photocatalysts for the synthesis of disulfides by oxidative coupling of thiols.

关键词： Triphenylamine Metal-organic frameworks Strontium Photooxidation Thiols Disulfides

Amino acids in piglet diarrhea:Effects,mechanisms and insights

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Animal Nutrition 2024年第1期16卷 267-274页

作者： Xihong Zhou Jing Liang xia Xiong Yulong Yin Key Laboratory of Agro-ecological Processes in Subtropical Region Institute of Subtropical AgricultureThe Chinese Academy of SciencesChangsha 410125China College of Advanced Agricultural Sciences University of Chinese Academy of SciencesBeijing 100049China

Piglet diarrhea is among one of the most serious health problems faced by the pig industry,resulting in significant economic *** disease in piglets has a multifactorial etiology that is affected by physiology,environment,and management *** is the most apparent symptom of intestinal *** a key class of essential nutrients in the piglet diet,amino acids confer a variety of beneficial effects on piglets in addition to being used as a substrate for protein synthesis,including maintaining appropriate intestinal integrity,permeability and epithelial renewal,and alleviating morphological damage and inflammatory and oxidative ***,provision of appropriate levels of amino acids could alleviate piglet *** amino acid effects are mediated by metabolites,gut microbes,and related signaling *** this review,we summarize the current understanding of dietary amino acid effects on gut health and diarrhea incidence in piglets,and reveal the mechanisms *** also provide ideas for using amino acid blends and emphasize the importance of amino acid balance in the diet to prevent diarrhea in piglets.

关键词： Piglet Amino acid Diarrhea Gut microbe Immune

Improved STNModels and Heuristic Rules for Cooperative Scheduling in Automated Container Terminals

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Computer Modeling in Engineering & Sciences 2024年第2期138卷 1637-1661页

作者： Hongyan xia Jin Zhu Institute of Logistics Science and Engineering Shanghai Maritime UniversityShanghai201306China

Improving the cooperative scheduling efficiency of equipment is the key for automated container terminals to copewith the development trend of large-scale ships. In order to improve the solution efficiency of the existing spacetimenetwork (STN) model for the cooperative scheduling problem of yard cranes (YCs) and automated guidedvehicles (AGVs) and extend its application scenarios, two improved STN models are proposed. The flow balanceconstraints in the original model are decomposed, and the trajectory constraints of YCs and AGVs are added toacquire the model STN_A. The coupling constraint in STN_A is updated, and buffer constraints are added toSTN_A so that themodel STN_B is *** the size of the problem increases, the solution speed of CPLEX becomesthe bottleneck. So a heuristic method containing three groups of heuristic rules is designed to obtain a near-optimalsolution quickly. Experimental results showthat the computation time of STN_A is shortened by 49.47% on averageand the gap is reduced by 1.69% on average compared with the original model. The gap between the solution ofthe heuristic rules and the solution of CPLEX is less than 3.50%, and the solution time of the heuristic rules is onaverage 99.85% less than the solution time of CPLEX. Compared with STN_A, the computation time for solvingSTN_B increases by 58.93% on average.

关键词： Automated container terminal buffer cooperative scheduling heuristic rules space-time network

Effects of fracture evolution and non-Darcy flow on the thermal performance of enhanced geothermal system in 3D complex fractured rock

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International Journal of Mining Science and Technology 2024年第4期34卷 443-459页

作者： Yachen Xie Jianxing Liao Pengfei Zhao Kaiwen xia Cunbao Li Department of Civil and Mineral Engineering University of TorontoToronto M5S1A4Canada College of Water Resources and Hydropower Sichuan UniversityChengdu 610225China State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsWuhan 430071China College of Civil Engineering Guizhou UniversityGuiyang 550025China Institute of Geosafety School of Engineering and TechnologyChina University of GeosciencesBeijing 100083China State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering Shenzhen UniversityShenzhen 518060China

In fractured geothermal reservoirs,the fracture networks and internal fluid flow behaviors can significantly impact the thermal *** this study,we proposed a non-Darcy rough discrete fracture network(NR-DFN)model that can simultaneously consider the fracture evolution and non-Darcy flow dynamics in studying the thermo-hydro-mechanical(THM)coupling processes for heat extraction in geothermal *** further employed the model on the Habanero enhanced geothermal systems(EGS)project located in ***,our findings illustrate a clear spatial-temporal variation in the thermal stress and pressure perturbations,as well as uneven spatial distribution of shear failure in 3D fracture *** shear failure is mainly concentrated in the first fracture ***,channeling flow have also been observed in DFNs during heat extraction and are further intensified by the expansion of fractures driven by thermal ***,the combined effect of non-Darcy flow and fracture evolution triggers a rapid decline in the resulting heat rate and *** NR-DFN model framework and the Habanero EGS's results illustrate the importance of both fracture evolution and non-Darcy flow on the efficiency of EGS production and have the potential to promote the development of more sustainable and efficient EGS operations for stakeholders.

关键词： Coupled THM model Non-Darcy flow Deformable DFN Enhanced geothermal systems

Design of integral sliding mode guidance law based on disturbance observer

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Journal of Systems Engineering and Electronics 2024年第1期35卷 186-194页

作者： ZHOU Jianping ZHANG Wenjie ZHOU Hang LI Qiang xia Qunli School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China School of Informatic Engineering Mianyang Techers’CollegeMianyang 62100China Beijing Institute of Electronic System Engineering Beijing 100854China Beijing Institute of Space Long March Vehicle Beijing 100076China

With the increasing precision of guidance,the impact of autopilot dynamic characteristics and target maneuvering abilities on precision guidance is becoming more and more *** order to reduce or even eliminate the autopilot dynamic operation and the target maneuvering influence,this paper suggests a guidance system model involving a novel integral sliding mode guidance law(ISMGL).The method utilizes the dynamic characteristics and the impact angle,combined with a sliding mode surface scheme that includes the desired line-ofsight angle,line-of-sight angular rate,and second-order differential of the angular *** the same time,the evaluation scenario considere the target maneuvering in the system as the external disturbance,and the non-homogeneous disturbance observer estimate the target maneuvering as a compensation of the guidance *** proposed system’s stability is proven based on the Lyapunov stability *** simulations reveale that ISMGL effectively intercepted large maneuvering targets and present a smaller miss-distance compared with traditional linear sliding mode guidance laws and trajectory shaping guidance ***,ISMGL has a more accurate impact angle and fast convergence speed.

关键词： disturbance observer pilot dynamics integral sliding mode impact angle constraint maneuvering target