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Influence of graphene on corrosion properties of micro arc oxidation coatings on 7075 aluminum alloy

INTERNATIONAL JOURNAL OF APPLIED CERAMIC technology 2024年第5期21卷 3516-3525页

作者： Chen, Xiaowen Tang, Song Zhang, Defen Yan, Jingzhi Xie, Wanlin Ran, Qingzheng Southwest Petr Univ Sch New Energy & Mat Chengdu Peoples R China Southwest Petr Univ Sch New Energy & Mat Chengdu 610500 Sichuan Peoples R China

This study uses 7075 aluminum alloy as the base material and employs micro arc oxidation technology to prepare ceramic coatings with different concentrations of graphene particles on the surface of the 7075 aluminum alloy. The effects of graphene particle concentration on micro arc oxidation behavior and coating performance were investigated through X-ray diffraction, scanning electron microscope, electrochemical testing, and other performance characterization methods. The research results show that the addition of graphene particles helps to promote the transformation of metastable gamma-Al2O3 to stable alpha-Al2O3, thereby enhancing the corrosion properties of the coating. When the concentration of graphene particles is 3 g/L, the prepared micro arc oxidation coating has the maximum thickness and hardness, which are 17.13 mu m and 886.76 HV0.3, respectively, while the porosity and roughness are the smallest, which are .39 mu m and 4.79%, respectively. Electrochemical test results show that the self-corrosion current density is the smallest at this concentration, which is 2.323 x 10-9A/cm2. Therefore, the addition of graphene particles can effectively improve the corrosion properties of 7075 aluminum alloy.

关键词： 7075 aluminum alloy corrosion properties graphene particles micro-arc oxidation

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Reliability of Tie Bar Concrete-Filled Steel Tubular Stub Columns Under Axial Compression

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INTERNATIONAL JOURNAL OF CIVIL engineering 2023年第7期21卷 1077-1087页

作者： Ding, Faxing Lu, Yongquan Xiong, Shuning Xiang, Ping Cent South Univ Sch Civil Engn Changsha 410075 Hunan Peoples R China Natl Engn Lab High Speed Railway Construction Changsha Peoples R China Tianjin Univ State Key Lab Hydraul Engn Simulat & Safety Tianjin Peoples R China Chongqing Univ Chongqing Key Lab Earthquake Resistance & Disaster Chongqing Peoples R China Changan Univ Minist Educ Highway Construct & Maintenance Equipm Engn Res Ctr Xian Peoples R China Wuhan Univ Technol Hubei Key Lab Theory & Applicat Adv Mat Mech Wuhan 430070 Peoples R China

Monte Carlo Simulation is implemented to analyze the reliability of the ordinary concrete-filled steel tubular (CFST) and tie bar CFST short columns under axial compression. The influences of different section shape, material types, load combination, load ratio, stirrup ratio and stirrup strength on the reliability indexes are evaluated. The results show: Properly configuring tie bars in ordinary CFST can greatly improve the reliability index of CFST by 20-40%;When using the same material and the same load combination, the reliability index of the circular section is the lowest;for CFST axial compression members with the same section shape, when the ratio of office live load to dead load is equal to 1.0, the higher the steel strength and concrete strength, the greater the reliability index.

关键词： Monte Carlo simulation Concrete-filled steel tube Axial compression Reliability

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In vitro digestion and fecal fermentation of basidiospore-derived exopolysaccharides from Naematelia aurantialba

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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES 2024年第Pt 1期261卷 129756页

作者： Sun, Tao Liang, Xiaoning Xu, Xiaoyi Wang, Linhao Xiao, Wei Ma, Yuhang Wang, Rui Gu, Yian Li, Sha Qiu, Yibin Sun, Dafeng Xu, Hong Lei, Peng Nanjing Tech Univ Coll Food Sci & Light Ind State Key Lab Mat Oriented Chem Engn Nanjing 211816 Peoples R China Inst All China Federat Supply & Mkt Cooperat Kunming Edible Fungi Inst Kunming 650032 Yunnan Peoples R China Nanjing Tech Univ Nanjing Peoples R China

Mushroom polysaccharides exhibit numerous health-enhancing attributes that are intricately linked to the breakdown, assimilation, and exploitation of polysaccharides within the organism. Naematelia aurantialba polysaccharides (NAPS-A), highly prized polysaccharides derived from mushrooms, remain shrouded in uncertainty regarding their characteristics pertaining to gastrointestinal digestion and gut microbial fermentation. The study aimed to understand the digestion and fecal fermentation patterns of NAPS-A. After simulated digestion, NAPS-A's physicochemical properties remained unchanged. However, during in vitro fecal fermentation, indigestible NAPS-A underwent significant changes in various properties, such as reducing sugar, chemical composition, constituent monosaccharides, Molecular weight, apparent viscosity, FT -IR spectra, and microscopic morphology. Notably, NAPS-A was effectively utilized by the gut microbiota, with unchanged properties after digestion but altered after fermentation. It influenced gut microbe composition by increasing beneficial bacteria (Lactobacillus, Faecalibacterium, and Roseburia), lowering pH, and producing short-chain fatty acids. NAPS-A fermentation enriches carbohydrate, fatty acid, and amino acid metabolic pathways through PICRUSt prediction analysis. Overall, these findings emphasize NAPS-A's role in regulating gut bacteria and their metabolic functions, despite its challenging digestibility.

关键词： Naematelia aurantialba polysaccharides In vitro digestion Gut microbiota Chemical structure

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Brake-by-wire system for passenger cars: A review of structure, control, key technologies, and application in X-by-wire chassis

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ETRANSPORTATION 2023年 18卷

作者： Zhang, Lei Wang, Qi Chen, Jun Wang, Zhen-Po Li, Shao-Hua Chongqing Univ State Key Lab Mech Transmiss Adv Equipment Chongqing 400044 Peoples R China Beijing Inst Technol Natl Engn Res Ctr Elect Vehicles Beijing Peoples R China Oakland Univ ECE Dept Rochester MI 48309 USA Shijiazhuang Tiedao Univ State Key Lab Mech Behav & Syst Safety Traff Engn Shijiazhuang 050043 Peoples R China

Electrification, networking and intelligence are the major development trends of the modern automobile industry for improving efficiency and safety and reducing emissions of the transport system. As an integral component of a wire-controlled chassis in passenger cars, brake-by-wire (BBW) system plays a key role in improving braking energy efficiency, safety, and ride comfort. This paper presents a systematic and complete review on BBW and its related technologies in passenger car applications. First, the architectures and working principles of major BBW systems are covered in details. Then, state-of-art control strategies for BBW systems are expounded. In particular, BBW-involved active safety control are presented. Finally, the remaining challenges and future research directions are discussed. The integrated design of BBW is a major development direction while other BBW systems except the Electro-Hydraulic System still need to solve some key technological challenges. Besides, efficient coordinated control of the X-by-wire chassis remains an open topic. In particular, the application of BBW in the X-by-wire chassis is a research hotspot.

关键词： Brake-by-wire system Electric vehicle Composite braking Regenerative braking Skateboard chassis

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Durability of micro-cracked UHPC subjected to coupled freeze-thaw and chloride salt attacks

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CEMENT & CONCRETE COMPOSITES 2024年 148卷

作者： Zhong, Rui Ai, Xianbing Pan, Mingyan Yao, Yiming Cheng, Zhao Peng, Xin Wang, Jingquan Zhou, Wei Wuhan Univ State Key Lab Water Resources Engn & Management Wuhan 430072 Peoples R China Southeast Univ Sch Civil Engn Key Lab Concrete & Prestressed Concrete Struct Min Nanjing 211189 Peoples R China Southeast Univ Engn Res Ctr Safety & Protect Explos & Impact Mini Sch Civil Engn Nanjing 211189 Peoples R China Southeast Univ Natl Key Lab Safety Durabil & Hlth Operat Long Span Bridges Nanjing 211189 Peoples R China

The durability of ultra-high performance concrete (UHPC) with initial micro-cracking subjected to coupled freeze-thaw and chloride salt (FT-CS) attacks was investigated. The initial micro-cracking was introduced under controlled condition in the laboratory by pre-tensioning the dog-bone specimens and unloading them at a target strain of 1500 mu epsilon. The micro-cracked UHPC specimens were then submerged in a sodium chloride solution with the concentration of 4 wt% and subjected to freeze-thaw (F-T) cycles. The micro-cracked UHPCs exhibited excellent chloride penetration resistance as evidenced by the consistently low chloride ion concentration (generally less than 0.5%) and the limited penetration depth (not exceeding 6 mm) even after undergoing 300 cycles of the coupled FT-CS attacks. The tensile strength and compressive strength of the micro-cracked UHPC were improved by 28.0% and 18.3% at 200 F-T cycles, respectively. The improvement in the mechanical properties can be attributed to the self-healing effect which densified the fiber-matrix interface and the matrix. Secondary hydration and carbonation were confirmed quantitatively by thermogravimetric test and qualitatively by scanning electron microscopy test. However, the detrimental effects stemming from the coupled FT-CS attacks outweighed the beneficial effect of self-healing at 300 F-T cycles, resulting in a decline in mechanical performance.

关键词： UHPC Durability Self-healing Freeze-thaw Chloride penetration

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Resilient tightly coupled INS/UWB integration method for indoor UAV navigation under challenging scenarios

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Defence technology（防务技术） 2023年第4期22卷 185-196页

作者： Qian Meng Yang Song Sheng-ying Li Yuan Zhuang Key Laboratory of Micro-Inertial Instrument and Advanced Navigation Technology Southeast UniversityNanjing210096China Department of Mechanical Engineering Hong Kong Polytechnic UniversityHong KongChina State Key Laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan UniversityWuhanChina

Based on the high positioning accuracy,low cost and low-power consumption,the ultra-wide-band(UWB)is an ideal solution for indoor unmanned aerial vehicle(UAV)localization and ***,the UWB signals are easy to be blocked or reflected by obstacles such as walls and furniture.A resilient tightly-coupled inertial navigation system(INS)/UWB integration is proposed and implemented for indoor UAV navigation in this paper.A factor graph optimization(FGO)method enhanced by resilient stochastic model is established to cope with the indoor challenging *** deal with the impact of UWB non-line-of-sight(NLOS)signals and noise uncertainty,the conventional neural net-works(CNNs)are introduced into the stochastic modelling to improve the resilience and reliability of the *** on the status that the UWB features are limited,a‘two-phase'CNNs structure was designed and implemented:one for signal classification and the other one for measurement noise *** proposed resilient FGO method is tested on flighting UAV platform under actual indoor challenging *** to classical FGO method,the overall positioning errors can be decreased from about 0.60 m to centimeter-level under signal block and reflection *** superiority of resilient FGO which effectively verified in constrained environment is pretty important for positioning accuracy and integrity for indoor navigation task.

关键词： Unmanned aerial vehicle(UAV) Resilient navigation Indoor positioning Factor graph optimization Ultra-wide band(UWB)

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Friction-induced temperature rise at energetic β-HMX crystal interfaces: Part II. Simulation of HMX rough surface under dry friction conditions

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TRIBOLOGY INTERNATIONAL 2024年 197卷

作者： Duan, Huijing Li, Guocheng Liu, Rui Zhang, Hao Yu, Jiaxin Yin, Ying He, Hongtu China Acad Engn Phys Inst Chem Mat Mianyang 621999 Peoples R China Southwest Univ Sci & Technol Key Lab Testing Technol Mfg Proc Minist Educ Mianyang 621010 Peoples R China Beijing Inst Technol State Key Lab Explos Sci & Safety Protect Beijing 100081 Peoples R China

In this study, the frictional temperature rise of HMX/HMX is investigated with a rough surface sliding on a flat surface by finite element method. The simulation model on the frictional temperature on HMX surface is validated by the in-situ temperature monitoring at moderate friction conditions by tribological experiments and friction-induced ignition of HMX at extreme conditions by friction sensitivity tests. Simulation results reveal that the significance order of frictional parameter that determine the maximum temperature on the asperity of HMX is: friction coefficient > sliding speed > contact pressure. Surface roughness of HMX surface can also affect the frictional temperature rise. Furthermore, a frictional power density of similar to 10.8 W/mm(2) is determined as the critical security boundary of the friction system when the critical temperature is set to 220 degrees C. These findings can provide deep insights into the microscale hot-spot formation and frictional safety mechanisms of explosives.

关键词： beta-HMX Dry friction Temperature rise Rough surface

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Independent and Free Control of Multiple Beams Enabled by Wideband Spin-Decoupled Metasurface

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advanced OPTICAL MATERIALS 2025年第6期13卷

作者： Li, Fengxia Yin, Xiaohan Yin, Jia-Yuan Deng, Jing-Ya Xidian Univ Sch Phys Xian 710071 Peoples R China Univ Elect Sci & Technol China Natl Engn Res Ctr Electromagnet Radiat Control Mat Chengdu 611731 Peoples R China Southeast Univ State Key Lab Millimeter Waves Nanjing 210096 Peoples R China

Pancharatnam-Berry (PB) phase is typically employed to control circularly polarized (CP) waves, but it has spin-locked limitations due to its conjugate phase response to different spins. Recently, by modulating both propagation and PB phases, spin-decoupled metasurfaces have attracted much attention. Most of these spin-decoupled metasurfaces are realized by regulating co-polarized components, which need N meta-atoms to achieve a 360 degrees phase coverage. However, this research on wideband high-efficiency spin-decoupled metasurfaces based on polarization conversion meta-atoms by adjusting cross-polarized components is still lacking. Compared with the regulation of co-polarized components, only N/2 meta-atoms are needed for the regulation of cross-polarized components, which greatly reduces the design difficulty. Here, two spin-decoupled metasurfaces are proposed for the generation of multiple vortex beams and pencil beams, which exhibit broadband and high-efficiency performance at the frequency range of 9-21 GHz. This work has the potential to significantly promote the development of wideband polarization multiplexing and multichannel meta-devices, with various applications in cyberspace security, wireless communication, imaging, and target detection.

关键词： metasurface orbital angular momentum polarization conversion spin-decoupled wideband

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Cu-based MOF-derivatived catalyst for efficient electrocatalytic reduction of nitrogen and nitrate to produce ammonia

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IONICS 2023年第6期29卷 2515-2522页

作者： Li, Guangxin Xue, Sensen Zhu, Haiding Liang, Zhuangzhuang Zhao, Fang Hua, Qianqian Ren, Xuefeng Xiong, Wei Gao, Liguo Liu, Anmin Dalian Univ Technol Sch Chem Engn State Key Lab Fine Chem Dalian Peoples R China Dalian Univ Technol Sch Ocean Sci & Technol Panjin 124221 Peoples R China Dalian Univ Technol Sch Environm Sci & Technol Key Lab Ind Ecol & Environm Engn Minist Educ Dalian 116024 Peoples R China

Electrochemical synthesis of ammonia is considered to be a promising approach due to its environmentally friendly process, great effort has been made for improving the catalyst to obtain satisfying catalytic activity and selectivity. Herein, we attempted to prepare the MOF-based derivative Cu/Cu2O@C via the wet method for N-2 and NO3- reduction to synthesize ammonia. For the nitrogen reduction, the as-prepared catalyst exhibited an excellent ammonia yield (6.02 mu mol center dot cm(-2)center dot h(-1)) and Faraday efficiency (FE, 10.48%) at - 0.5 V. While the overall yield of catalytic nitrate reduction reached 158.66 mu mol center dot cm(-2)center dot h(-1) and the FE reached 76.97% owing to higher solubility and a better conversion pathway. This is considerably higher than the yield of nitrogen reduction while preventing the energy consumption of reforming hydrogen production. This work helps to promote the development of artificial ammonia synthesis under ambient conditions.

关键词： Catalyses Materials Preparations

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Improved Meet-in-the-Middle Attacks on Reduced-Round Tweakable Block Cipher Deoxys-BC

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COMPUTER JOURNAL 2022年第9期65卷 2411-2420页

作者： Li, Manman Chen, Shaozhen State Key Lab Math Engn & Adv Comp 62 Kexue Rd Zhengzhou 450001 Peoples R China

Deoxys-BC is an internal tweakable block cipher of the authenticated encryption algorithm Deoxys, which is a third-round finalist in the CAESAR competition. In this paper, we study the property of Deoxys-BC, such as the subtweakey difference cancelation and the freedom of the tweak. Combining the differential enumeration technique with these properties, the authors achieve the key-recovery attacks on Deoxys-BC under the meet-in-the-middle attack. As a result, we get an attack on 9-round Deoxys-BC-128-128 by constructing a 6-round meet-in-the-middle distinguisher with 2(113) plaintext-tweak combinations, 2(97) Deoxys-BC blocks and 2(121.6) 9-round Deoxys-BC-128-128 encryptions. We also present an attack on 11-round Deoxys-BC-256-128 for the first time by constructing a 7-round meet-in-the-middle distinguisher with 2113 plaintext-tweak combinations, 2(226) Deoxys-BC blocks and 2(251) 11-round Deoxys-BC-256-128 encryptions.

关键词： Deoxys-BC cryptanalysis tweakable block cipher meet-in-the-middle attack

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