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Poly(dimethyl-diphenyl-imide)siloxane/phenolic-based double network hybrid resin coatings for ablation thermal protection

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PROGRESS IN ORGANIC COATINGS 2023年 182卷

作者： Yuan, Quan Yan, Liwei Tian, Jinfeng Xia, Shuang Heng, Zhengguang Liang, Mei Chen, Yang Zou, Huawei Sichuan Univ Polymer Res Inst State Key Lab Polymer Mat Engn Chengdu 610065 Peoples R China

Organic-inorganic hybridization is an important way to improve ablation resistance of phenolic resin coatings (PR). However, long molecular chain silicone by copolymerization is less compatible with PR and hybrid resin will form sea-island phase, which is not favorable for further improvement of ablation resistance. Therefore, how to achieve a combination of long chain and compatibility is a major challenge. In this work, the poly(dimethyldiphenyl-imide)siloxane (PMPI) containing imide and phenyl was synthesized by anionic ring-opening polymerization and copolymerization. Then, it was hybridized with PR to obtain PMPI/PR-based double network hybrid resin coatings with nano co-continuous phase. The oxyacetylene ablation test suggests that the resin coatings with medium phenyl content has the lowest linear ablation rate (0.055 mm/s), which is 74 % lower compared to PR (0.21 mm/s). In addition, the mechanism by which PMPI enhances ablation resistance is discussed. This work provides a promising approach to develop higher performance ablative-resistant resin coatings.

关键词： Coatings Silicone Phenolic resin Co -continuous structure Copolymer

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Efficient Persistent Fault Analysis with Small Number of Chosen Plaintexts

IACR Transactions on Cryptographic Hardware and Embedded Sys...

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IACR Transactions on Cryptographic Hardware and Embedded Systems 2023年第2期2023卷 519-542页

作者： Zhang, Fan Huang, Run Feng, Tianxiang Gong, Xue Tao, Yulong Ren, Kui Zhao, Xinjie Guo, Shize School of Cyber Science and Technology College of Computer Science and Technology Zhejiang University Hangzhou310027 China Alibaba-Zhejiang University Joint Research Institute of Frontier Technologies Hangzhou310027 China Key Laboratory of Blockchain and Cyberspace Governance of Zhejiang Province Hangzhou310027 China Henan Province Key Laboratory of Cyberspace Situation Awareness Zhengzhou450001 China Shanghai Institute of Satellite Engineering Shanghai201109 China

In 2018, Zhang et al. introduced the Persistent Fault Analysis (PFA) for the first time, which uses statistical features of ciphertexts caused by faulty Sbox to recover the key of block ciphers. However, for most of the variants of PFA, the prior knowledge of the fault (location and value) is required, where the corresponding analysis will get more difficult under the scenario of multiple faults. To bypass such perquisite and improve the analysis efficiency for multiple faults, we propose Chosen-Plaintext based Persistent Fault Analysis (CPPFA). CPPFA introduces chosen-plaintext to facilitate PFA and can reduce the key search space of AES-128 to extremely small. Our proposal requires 256 ciphertexts, while previous state-of-the-art work still requires 1509 and 1448 ciphertexts under 8 and 16 faults, respectively, at the only cost of requiring 256 chosen plaintexts. In particular, CPPFA can be applied to the multiple faults scenarios where all fault locations, values and quantity are unknown, and the worst time complexity of CPPFA is O(28+nf) for AES-128, where nf represents the number of faults. The experimental results show that when nf > 4, 256 pairs of plaintext-ciphertext can recover the master key of AES-128. As for LED-64, only 16 pairs of plaintext-ciphertext reduce the remaining key search space to 210. © 2023, Ruhr-University of Bochum. All rights reserved.

关键词： Side channel attack

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Influence of Associated Cations on the Transport and Adsorption of Chloride Ions in the Nano-channel of Calcium Aluminosilicate Hydrate Gel:A Molecular Dynamics Study

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Journal of Wuhan University of technology(Materials Science) 2022年第5期37卷 963-976页

作者： YANG Jun ZHANG Gaozhan DING Qingjun WANG Aiguo HOU Dongshuai Anhui Province Engineering Laboratory of Advanced Building Materials School of Materials and Chemical EngineeringAnhui Jianzhu UniversityHefei230601China State Key Laboratory of Silicate Materials for Architectures School of Materials Science and EngineeringWuhan University of TechnologyWuhan430070China School of Materials Science and Engineering Department of Civil EngineeringQingdao University of TechnologyQingdao266033China

Molecular dynamics simulation was utilized to investigate the transport and adsorption of chloride in the nanopore of calcium aluminosilicate hydrate(C-A-S-H)with associated cation types of Ca,Mg,Na and *** local ionic structure,atomic dynamics and bond stability were analyzed to elucidate the interaction between cations and chloride *** results show that interfacial chloride is absorbed through the ion pairing formation in the vicinity of C-A-S-H *** cations can simultaneously interact aluminosilicate chains,water molecules and Cl^(-)ions,which restrict the motion of interfacial Cl^(-)*** solution chloride can be immobilized through the solvation effect of *** along with their hydration shell can connect to neighboring Cl^(-)ions to decrease their *** to the varied ionic chemistry,cations show different interaction strength with neighboring water molecules and anions,which determines the chloride transport behavior in the nanopore of *** chloride immobilization capacity of C-A-S-H nanopore with different associated cations is listed in following order:Mg^(2+)Ca^(2+)

关键词： calcium aluminosilicate hydrate nanometer channel confinement chloride immobilization associated cations ionic structure

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Microstructure and Nanoindentation Creep Behavior of Binary Al-Cu Alloy Synthesized at High Pressure

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JOM 2023年第1期75卷 176-183页

作者： Ma, Pan Zhang, Zhiyu Liu, Xiao Shi, Xuerong Prashanth, Kondagokuldoss Jia, Yandong Shanghai Univ Engn Sci Sch Mat Sci & Engn Shanghai Peoples R China Harbin Inst Technol State Key Lab Adv Welding & Joining Harbin 150001 Peoples R China Tallinn Univ Technol Dept Mech & Ind Engn Tallinn Estonia Austrian Acad Sci Erich Schmid Inst Mat Sci Jahnstr 12 Leoben Austria Vellore Inst Technol Sch Mech Engn CBCMT Vellore Tamil Nadu India Shanghai Univ Inst Mat Shanghai 200444 Peoples R China

Al-xCu alloys (x = 5 wt.%, 15 wt.%, 33 wt.%, and 40 wt.%) were solidified at atmospheric pressure (AP) and at high pressure of 3 GPa (3 GPa). The microstructural evolution was studied, and it shows that the amount of eutectic Al2Cu phase is suppressed in the Al-xCu samples solidified under high pressure compared to the samples solidified under ambient conditions. In addition, the secondary dendritic arm spacing in the Al-15Cu and Al-33Cu alloy decreases when solidified under high pressure. The strain rate sensitivity (m) and activation volume (V*) were calculated from the nanoindentation experiments, and the results show that m increases while V* decreases for the hypoeutectic Al-5Cu and Al-15Cu alloys solidified at 3 GPa. Both m and V* decrease for the eutectic alloy (Al-33Cu), and for the hypereutectic composition (Al-40Cu), m decreases, whereas V* increases when solidified under high pressure. The results suggest that both the strength and plasticity for the hypoeutectic compositions increase simultaneously, while the plasticity decrease in the eutectic composition solidified under high pressure. On the other hand, for the hypereutectic Al-40Cu alloy solidified under 3 GPa, both the strength and plasticity decrease.

关键词： Copper alloys

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Enhanced ablation resistance of carbon/phenolic composites based on mesophase pitch reinforced particles

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JOURNAL OF APPLIED POLYMER SCIENCE 2023年第41期140卷 e54529-e54529页

作者： Yue, Yaoqun Huang, Yisen Zou, Huawei Chen, Yang Liang, Mei Sichuan Univ Polymer Res Inst State Key Lab Polymer Mat Engn Chengdu Peoples R China Sichuan Univ Polymer Res Inst State Key Lab Polymer Mat Engn Chengdu 610065 Peoples R China

Phenolic resin (PR)-based composites are the main materials used in thermal protection system (TPS) at present. However, the low graphitization degree of the char layer formed by PR easily leads to cracks and other defects. In this study, carbon/phenolic composites were modified by mesophase pitch (MP) to improve the structural strength, fracture toughness and crack propagation resistance. The ablation rate was significantly decreased after MP modification compared with the blank sample. With the increase of MP, the size of cracks and char blocks on the ablation center of the composites were reduced, and the surface was flat and dense. The Interlaminar shear strength (ILSS) of carbonized composites (5 wt% MP) were 9.79 MPa, and the flexural strength was 121.5 MPa, which improved 62.9% and 40.8% relative to the pure sample. The flexural strength of 5 wt% MP-reinforced carbon/phenolic composites reached 525.6 MPa, which was 26.9% higher than that of pure carbon/phenolic composites, mainly due to the particle reinforcement effect of MP distributed between carbon fibers. The above results show that the carbon/phenolic composites modified by MP has great application prospects in the field of aircraft thermal protection.

关键词： ablative performance carbon phenolic composites mesophase pitch

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Accelerating anammox nitrogen removal in lowintensity ultrasound-assisted ASBBR: Performance optimization, EPS characterization and microbial community analysis

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SCIENCE OF THE TOTAL ENVIRONMENT 2022年 817卷 152989-152989页

作者： Zhang, Wei Zhou, Xin Cao, Xiwei Li, Shuhan Taiyuan Univ Technol Coll Environm Sci & Engn Taiyuan 030024 Peoples R China Innovat Ctr Postgrad Educ Municipal Engn Shanxi P Taiyuan 030024 Peoples R China

Efficient enrichment of slow-growing anammox species is essential for rapid start-up and stable operation of high-rate anammox reactors. Herein, a low intensity ultrasound (LIU) was introduced into anaerobic sequencing batch biofilm reactors (ASBBRs) to enhance anammox nitrogen removal from nitrogen-rich wastewater. Operation results demonstrated that the maximum total nitrogen (TN) removal efficiency of 91.5% were achieved under the optimal ultrasonic parameters (32.7 degrees C water temperature, 0.18 W/cm(2) ultrasonic intensity and 25.7 min ultrasonication time). Moreover, significant increases of extracellular polymeric substances (EPS) components and contents were observed via the ultrasonication stimulation. A close correlation between nitrogen removal and shifts in transformation and intensity of spectrum peaks was also verified by three-dimensional excitation-emission matrix spectroscopy (3D-EEM) analysis. High-throughput sequencing revealed that the relative abundance of Candidatus Kuenenia as the key anammox consortium significantly increased after applying optimal ultrasonication condition. Furthermore, enhancement mechanisms and future prospect of the LIU-assisted anammox process was elucidated and discussed. This research provides a viable and promising acceleration strategy for anammox-based process in practice.

关键词： Anammox Low intensity ultrasound Nitrogen removal EPS Microbial community

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Utilization of fly ash as building material admixture: Basic properties and heavy metal leaching

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CASE STUDIES IN CONSTRUCTION MATERIALS 2022年 17卷

作者： Wang, Chao-qiang Liu, Ke Huang, De-ming Chen, Qiao Tu, Min-jie Wu, Kai Shui, Zhong-he Chongqing Jiaotong Univ Sch Mat Sci & Engn Chongqing 400074 Peoples R China Chongqing Inst Modern Construct Ind Dev Chongqing 400066 Peoples R China Chinese Acad Sci Chongqing Inst Green Intelligent Technol Chongqing 400714 Peoples R China CSCEC Strait Construct & Dev Co Ltd Fuzhou 350015 Peoples R China Tongji Univ Minist Educ Key Lab Adv Civil Engn Mat Shanghai 201804 Peoples R China Wuhan Univ Technol State Key Lab Silicate Mat Architectures Wuhan 430070 Peoples R China

The potential harm to the environment and human body caused by heavy metal elements such as Cd, Cr, Pb in fly ash cannot be ignored. In this study, microscopic analysis and heavy metal hazard analysis were performed on fly ash samples from four regions in China. XRF, XRD, FTIR and SEM/ EDS test results showed that the main components of fly ash are Si, Ca, Al, O and other elements, and the main mineral components are mullite, quartz and amorphous aluminosilicate. The results showed that six heavy metal elements of As, Hg, Cd, Cr, Pb and Ni from the EDS test charts of these four types of fly ash. Based on the detection of the six heavy metal contents in fly ash, the results of the pollution evaluation of these four types of fly ash were consistent according to the single factor index, potential ecological risk index, and index of geo-accumulation. This indicated that Cd/Hg in FA 1, FA 2 and FA 3 has a high risk of environmental pollution. In the meantime, Cr and As in fly ash need to be controlled, because the human health risk assessment showed that they will bring carcinogenic risk to the human body through oral intake. The study on the migration law of characteristic heavy metals by taking FA 4 as an example showed that the leaching rate of Cr, Hg and Cd decreased with the increase of grinding particle size. Among the three characteristic heavy metals, mercury had the highest leaching rate. From the XPS detection results of FA 4, it was found that the valence states of these three heavy metals in FA 4 are Cr3+, Cr6+, Cd2+, Hg2+ respectively. These harmful heavy metal ions gradually enter the deep soil and groundwater through osmosis. Finally, based on the control model constructed in this study, the contents of these three heavy metals in fly ash in different application scenarios were limited.

关键词： Fly ash Heavy metal Leaching Admixture Ecological risk assessment

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A Review of Mechanical Properties and Improvement Methods of Medium Entropy Alloys at High Temperature

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JOM 2024年第1期76卷 353-361页

作者： Wang, Lei Jiao, Yichao Liu, Ruifan Wang, Deyu Yu, Zhigang Xi, Yuntao Zhang, Keren Xu, Shanna Liu, Haitao Wen, Lei Xiao, Xinke Zhang, Wei Ji, Jiangtao Xian Shiyou Univ Sch Mat Sci & Engn Xian 710065 Peoples R China Northeastern Univ State Key Lab Rolling & Automat Shenyang 110819 Peoples R China Tsinghua Univ State Key Lab Tribol Adv Equipment Beijing 100084 Peoples R China Univ Sci & Technol Beijing Nation Ctr Mat Serv Safety Beijing 100083 Peoples R China Nanyang Inst Technol Henan Int Joint Lab Dynam Impact & Disaster Engn Nanyang 473004 Peoples R China Shaanxi Coal Ind New Energy Technol Co Ltd Xian 710199 Shaanxi Peoples R China Changqing Oilfield Co Oil & Gas Technol Res Inst Xian 710021 Peoples R China Natl Engn Lab Low Permeabil Oil & Gas Explorat & Xian 710021 Peoples R China Univ Regina Fac Engn & Appl Sci Petr Syst Engn Regina SK S4S 0A2 Canada Northwest Inst Nonferrous Met Res Xian 710016 Shaanxi Peoples R China China Railway First Survey & Design Inst Grp Co L Xian 710043 Shaanxi Peoples R China

Medium-entropy alloys (MEA) have excellent mechanical properties and are extremely suitable for applications such as aerospace. However, almost all high- and medium-entropy alloys decrease in strength and ductility at high temperatures. As one of the alternative materials for turbine blades of aircraft engines, high/medium entropy alloys are inevitably subjected to coupling effects of high temperature and high strain rates during service. The present work focuses on improving the mechanical properties of MEAs and briefly describes the mechanical properties at high temperatures and high strain rates. Meanwhile, it integrates literature regarding the methods, including adding high melting point solutes, nanocrystalline MEA and non-isoatomic MEA, to improve the mechanical properties at high temperatures and high strain rates. Finally, we propose the potential research direction and possible problems medium entropy alloys may face in the future.

关键词： Entropy

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Combinatorial Synthesis of Covalent Organic Framework Particles with Hierarchical Pores and Their Catalytic Application

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JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 2023年第35期145卷 19283-19292页

作者： Li, Wei Bie, Zhengwei Zhang, Chi Xu, Xintong Wang, Song Yang, Yuhao Zhang, Ziyang Yang, Xuan Lim, Khak Ho Wang, Qingyue Wang, Wen-Jun Li, Bo-Geng Liu, Pingwei Zhejiang Univ Coll Chem & Biol Engn State Key Lab Chem Engn Hangzhou 310027 Zhejiang Peoples R China Inst Zhejiang Univ Quzhou Quzhou 324000 Peoples R China

Precise tailoring of the aggregationstate of covalent organicframeworks (COFs) to form a hierarchical porous structure is criticalto their performance and applications. Here, we report a one-pot andone-step strategy of using dynamic combinatorial chemistry to constructimine-based hollow COFs containing meso- and macropores. It relieson a direct copolymerization of three or more monomers in the presenceof two monofunctional competitors. The resulting particle productspossess high crystallinity and hierarchical pores, including microporesaround 0.93 nm, mesopores widely distributed in the range of 3.1-32nm, and macropores at about 500 nm, while the specific surface areacould be up to 748 m(2)& BULL;g(-1), withnon-micropores accounting for 60% of the specific surface area. Theparticles demonstrate unique advantages in the application as nanocarriersfor in situ loading of Pd catalysts at 93.8% loading efficiency inthe copolymerization of ethylene and carbon monoxide. The growth andassembly of the copolymer could thus be regulated to form flower-shapedparticles, efficiently suppressing the fouling of the reactor. Thecopolymer's weight-average molecular weight and the meltingtemperature are also highly improved. Our method provides a facileway of fabricating COFs with hierarchical pores for advanced applicationsin catalysis.

关键词： Covalent organic frameworks Diffraction Monomers Nanoparticles Polymers

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Substation Digital Twin Framework Design and key technology Research 3

Substation Digital Twin Framework Design and Key Technology ...

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3rd IEEE China International Youth Conference on Electrical engineering, CIYCEE 2022

作者： Jia, Guo Jinghai, Xie Mi, Sun Dongyu, Su Tao, Wang Youhang, Yang Shaorong, Wang Economic and Technological Research Institute State Grid Jibei Electric Power Co. Ltd Beijing100038 China Tangshan Electric Power Prospecting and Designing Institute Co. Ltd Hebei063000 China School of Electrical and Electronic Engineering Hust Hubei30074 China School of Electrical and Electronic Engineering Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Engineering and Technology Wuhan430074 China

ISBN: (数字)9781665477321

ISBN: (纸本)9781665477321

Digital twin (DT) is a key technology to improve the digital and intelligent level of substation operation and maintenance. In order to accelerate the application of DT in substations, this paper deeply studies the framework structure and key technologies of the substation DT. First, combined with the operational characteristics of substation, a five-dimensional DT model is proposed, which consists of physical entities of substation, digital models of substation, twin service, twin datasets, and the connection among the parts. Secondly, the framework structure for realizing the substation DT is designed, including device layer, perception layer, network layer, platform layer and application layer. Finally, the key technologies of substation DT are analyzed, and three technical aspects are elaborated from the application of 3D digital model fusion, the construction of substation lightweight digital model, and the interaction between data middle platform and application layer based on multi-agent. © 2022 IEEE.

关键词： Three dimensional computer graphics

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