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Pronounced impact of size and shape effects on creep rupture life of a K439B superalloy combustion chamber casting simulator

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China Foundry 2025年

作者： Wen-tong liu Yi-dong Wu Lei Gao Jing-yang Chen cheng-bo Xiao Xi-dong Hui State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Science and Technology on Advanced High Temperature Structural Materials Laboratory Beijing Institute of Aeronautical Materials

The size and shape effect(SSE) of components has become a critical issue for mechanical properties, application reliability, and processing. In this study, the creep rupture life(CRL) of components with different wall thicknesses and positions in a combustion chamber casing simulator made of K439B superalloy was investigated. The intrinsic mechanisms of the SSE were explored from the dendrite structure, volume fraction and size of the γ' phase, and element segregation, etc. It is shown that this casting exhibits a strong SSE of creep rupture life, characterized by a significant difference in the CRL values up to 60% with the variation of wall thickness and position in the casing. In terms of casting technology, the influence of SSE on CRL is actually determined by the cooling rate. The SSE on the creep rupture life originates from the dendrite structure(such as the secondary dendrite arm spacing), volume fraction size of the γ' phase in the dendrite trunk, and elements segregation rate. This work may have implications for the design and application of engineering components with large sizes and complex structures.

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基于CNN的监控视频中人脸图像质量评估

计算机系统应用 2018年第11期27卷 71-77页

作者：王亚朱明刘成林中国科学技术大学信息科学技术学院合肥230027

在公共安全领域,监控视频中的人脸识别技术是不可或缺的技术,成为研究热点.而监控视频中低质量的人脸图像会大大降低整个人脸识别系统的识别准确率,系统难以更广泛地被投入实际使用.本文提出了一种基于CNN的人脸图像质量评估方法.通过对... 详细信息

在公共安全领域,监控视频中的人脸识别技术是不可或缺的技术,成为研究热点.而监控视频中低质量的人脸图像会大大降低整个人脸识别系统的识别准确率,系统难以更广泛地被投入实际使用.本文提出了一种基于CNN的人脸图像质量评估方法.通过对Alexnet模型进行改进,将网络中的多个卷积层与全连接层连接,从而提取不同尺度的图像特征.通过端到端的训练过程,预测人脸图像质量分数.另外,采用人脸识别算法来标定人脸图像的质量分数,使质量分数能更有效地筛选出适合识别算法的图像.在Color FERET数据集上实验表明,本文方法能够准确地对人脸图像进行质量评估.而在实际采集的监控视频数据集上实验表明,本文方法能筛选出高质量的人脸图像用作后续人脸识别,提高人脸识别准确率.

关键词： CNN 人脸图像质量评估监控视频

Experimental Research on a Feasible Building Insulation Material Based Reed in China

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Journal of Thermal Science 2025年第1期34卷 176-187页

作者： liu Tiantian PENG Yizhe liu Lifang CAI chenghan WANG Shuang LI Hongqiang College of Civil Engineering Hunan University College of Civil Engineering Hunan University of Science and Technology School of Energy and Power Jiangsu University of Science and Technology National Center for International Research Collaboration in Building Safety and Environment (NCIRCBSE) Hunan University Key Laboratory of Building Safety and Energy Efficiency of the Ministry of Education Hunan University

The seemingly useless reeds are prepared as thermal insulation materials,which not only meet the requirements of environmental sustainability but also enhance the added value of reeds,creating new economic *** hydrophobicity of raw biomass surfaces leads to problems such as weak bonding strength and non-dense structure in the formed materials,as well as issues related to the residual insect infestations on the *** this study,reed straw was used as the raw material,and foamed geopolymer was used as the binder to prepare building insulation materials based *** improve the interfacial adhesion performance between reed straw and foamed geopolymer,a thermochemical modification method-thermal carbonization,was *** this study,the mechanical properties and hydraulic properties of the studied materials with different degrees of surface thermal modification were tested,especially the fire resistance performance,and weathering resistance performance rarely found in published *** the surface thermal modification condition of reed straw was 250℃（30 min）,the comprehensive performance of reed-based building insulation materials was the best,when the studied material density was 321.3 kg/m3;the compressive strength was 0.59 MPa;the thermal conductivity was 0.101 W/（m·K）;the pH was 11.27;the moisture absorption rate was 25.1%,and the compressive strength loss rate in wet-dry cycles was 18.5%.In addition,it had excellent fire resistance performance and weathering resistance *** new material can be widely used to improve the thermal insulation of traditional buildings and as sandwich filler in prefabricated buildings,such as preparing insulating walls.

关键词： building insulation material based reed fire resistance performance interface adhesion properties pre-treatment of reeds weathering resistance performance

Recent progress on photoactive nonprecious transition-metal complexes

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Science China Chemistry 2025年第1期68卷 46-95页

作者： Zhong-Liang Gong Hong-Jie Zhang Yan cheng Jianxun liu Yuhan Ai Yaqin Li Zhihui Feng Qiong Zhang Shaolong Gong Yong Chen Chang-Jiang Yao Yuan-Yuan Zhu Liang-Jin Xu Yu-Wu Zhong CAS Key Laboratory of Photochemistry Institute of Chemistry Chinese Academy of Sciences State Key Laboratory of Structural Cemistry Fujian Institute of Research on the Structure of Matter Chinese Academy of Sciences School of Chemistry and Chemical Engineering Anhui Key Laboratory of Advanced Catalytic Materials and Reaction EngineeringHefei University of Technology State Key Laboratory of Explosion Science and Safety Protection School of Mechatronical Engineering Beijing Institute of Technology College of Chemistry and Molecular Sciences Hubei Key Lab on Organic and Polymeric Optoelectronic Materials Wuhan University School of Chemistry and Chemical Engineering Anhui University Key Laboratory of Photochemical Conversion and Optoelectronic Materials & CAS-HKU Joint Laboratory on New Materials Technical Institute of Physics and Chemistry Chinese Academy of Sciences

Photoactive complexes of nonprecious transition metals, mainly including those in the first-row and partially the second-row of the Periodic table of elements, have received increasing attention in view of their low cost and long-term sustainability. They are recognized as promising alternatives to noble transition metal complex congeners that have been extensively studied in optoelectronic devices, artificial photosynthesis, photocatalysis, biodiagnostics, and therapeutics, etc. This review is devoted to a comprehensive summary on the classical and recent advances on photoactive nonprecious transition metal complexes, including photoactive Zr, V, Cr, Mo, and W complexes, Mn complexes and hybrids, Fe, Co, Ni, and Cu complexes, and Zn and Cd complexes and hybrids. A particular focus is given on the molecular design, modulation of photophysical and photochemical properties, and applications of the representative and lately-developed nonprecious metal complexes. In addition, a perspective on the future development in this field is provided at the end of this review.

关键词： photoactive metal complexes earth-abundant metals nonprecious metal complexes luminescence photochemistry

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黄土路堑边坡在振动作用下的动力响应分析

铁道工程学报 2008年第7期25卷 1-4,9页

作者：龚成明刘争平杨丹西南交通大学成都610031

研究目的:在黄土路堑基底加固中采用柴油柱锤打桩机产生振动的条件下,测试柱锤振动对黄土路堑边坡的动力响应,分析研究动力响应在水平地面与边坡上的差别,查找施工过程中黄土边坡坍塌的外在动力因素。研究结论:黄土路堑边坡在振动作用... 详细信息

研究目的:在黄土路堑基底加固中采用柴油柱锤打桩机产生振动的条件下,测试柱锤振动对黄土路堑边坡的动力响应,分析研究动力响应在水平地面与边坡上的差别,查找施工过程中黄土边坡坍塌的外在动力因素。研究结论:黄土路堑边坡在振动作用下的动力响应存在明显的放大效应,尤其是边坡的变坡点的动力响应明显强于自由场(水平地形)的动力响应,并随边坡的增高而逐渐衰减,但衰减速度较水平地面上缓慢得多。这种地形对振动产生的动力放大效应是引发黄土路堑边坡坍塌的重要因素之一,因此,在处理路堑基底时,应考虑边坡的临时防护与加固,确保施工过程中的稳定与安全。

关键词：边坡基底加固动荷载放大效应

Rational modulation of fluorophosphate cathode by anionic groups to reduce the polarization behavior for fast-charging sodium-ion batteries

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Journal of Energy Chemistry 2025年第1期100卷 509-521页

作者： Xinyuan Wang Fan Zhang Xingyu Zhou Qian Wang Changyu liu Yangyang liu Hui Wang Xiaojie liu Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education College of Chemistry & Materials Science Northwest University

Na3V2（PO4）2O2F （VP） is recognized as a promising cathode material for sodium-ion batteries due to its stable structural framework and high specific *** functional theory （DFT） and finite element simulations show that incorporating SO42-into VP decreases its band gap,lowers the migration energy barrier,and ensures a uniform Na+concentration gradient and stress distribution during charge and discharge ***,the average Na+diffusion coefficient of Na3V2（PO4）1.95（SO4）0.05O2F（VPS-1） is roughly double that of VP,leading to enhanced rate capability (80 C,75.5 mAh g-1) and cycling stability (111.0 mAh g-1capacity after 1000 cycles at 10 C current density) for ***-1 exhibits outstanding fast-charging capabilities,achieving an 80%state of charge in just 8.1 *** assembled VPS-1//SbSn/NPC full cell demonstrated stable cycling over 200 cycles at a high 5 C current,maintaining an average coulombic efficiency of 95.35%.

关键词： Anionic group modulation Polarization behavior Fast-charging Sodium-ion battery Fluorophosphate Cathode

Post-tunable salt gel electrolytes toward flexible supercapacitor switches

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Journal of Energy Chemistry 2025年第1期100卷 114-124页

作者： Hui Wang Shuang Chen Xuming liu Qin Zhang Xin liu Polymeric and Soft Materials Laboratory School of Chemistry and Life Science and Advanced Institute of Materials Science Changchun University of Technology Polymeric and Soft Materials Laboratory School of Chemical Engineering and Advanced Institute of Materials Science Changchun University of Technology

Convertible hydrogel supercapacitors have emerged as promising energy storage devices in switches,diodes, and transistors. However, inherent weaknesses in ionic conductivity, mechanical properties,and water retention of hydrogel electrolytes seriously hinder their development. Inspired by the hardness conversion of sea cucumber skin, a conductivity and mechanics dual-tunable salt gel electrolyte is successfully designed. The salt gel presents a reversible switching of conductors-insulators and a mechanical regulation between softness and hardness via the dissolution-crystallization transition of sodium acetate trihydrate（SAT）. Meanwhile, the salt gels spontaneously grow a layer of “armor” through saturated phase-change salt crystals effectively reducing water evaporation of hydrogel ***, this phase-change soft-rigid conversion strategy will expand the capabilities of gel-based flexible supercapacitors(area capacitance: 258.6 mF cm-2), and the capacitance retention rate could still reach 86.9% after 3000 cycles at high temperatures. Moreover, the salt gel supercapacitor is potentially used in over-heat alarm systems. It is anticipated that the strategy of conductivity and mechanics of dual-tunable salt gel would provide a new perspective on the development of energy storage devices,wearable electronics, and flexible robots.

关键词： Capacitance

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思想政治教育数字化的价值意蕴及实践进路

新疆师范大学学报（哲学社会科学版） 2025年第2期46卷 128-136页

作者：于祥成刘成合肥工业大学安徽合肥230009 武汉大学马克思主义学院湖北武汉430064

随着数字技术的广泛应用和教育数字化转型发展,数字化变革成为思想政治教育创新发展的必然选择。面对新的时代境遇,要全面把握思想政治教育数字化的内涵和特征,深刻认识思想政治教育数字化在推动思想政治教育认知重建、资源重组、话语... 详细信息

随着数字技术的广泛应用和教育数字化转型发展,数字化变革成为思想政治教育创新发展的必然选择。面对新的时代境遇,要全面把握思想政治教育数字化的内涵和特征,深刻认识思想政治教育数字化在推动思想政治教育认知重建、资源重组、话语重构、形态重塑等方面的重要价值。同时,要秉承数字理念,构建思想政治教育数字范式;搭建数字平台,优化思想政治教育数字服务;培育数字素养,提升思想政治教育数字技能;厚植“数字土壤”,形塑思想政治教育数字生态,积极探索思想政治教育数字化实践创新路径。

关键词：思想政治教育数字化数字技术实践进路

Ni-catalyzed cross-electrophile alkyl-alkyl coupling reactions

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Science China Chemistry 2025年

作者： Li-Xu You Lan Tian Chun-Ling Guo Shun-Xi Li Yu-cheng liu Yu-Long Li Wei Shu College of Chemistry and Environmental Engineering Key Laboratory of Green Catalysis of Higher Education Institutes of Sichuan Sichuan University of Science and Engineering Guangming Advanced Research Institute Shenzhen Grubbs Institute Department of Chemistry and Guangdong Provincial Key Laboratory of Catalysis Southern University of Science and Technology

Introducing saturated carbon-carbon bonds into organic molecules significantly increases the three-dimensional configuration,thus altering the physical and chemical properties as well as the functions of molecules. Transition-metal-catalyzed carboncarbon cross-couplings represent one of the most straightforward, efficient and modular alternatives to build saturation in a single step. However, the efficient construction of alkyl-alkyl bonds remains a formidable challenge due to the precise manipulation of multiple alkyl metallic intermediates as well as associated competitive side reactions and selectivity control. Over the past years, Ni-catalyzed cross-coupling under reductive conditions has gained more and more attention for alkyl-alkyl crosscoupling partially attributing to the low-valent state of metal centers under reducing conditions, which suppresses the competitive β-hydride elimination process, thus facilitating the formation of alkyl-alkyl bonds. In this review, the initiative and progress of Ni-catalyzed cross-electrophile alkyl-alkyl cross-coupling, including the efforts in racemic and enantioselective formation of alkyl-alkyl bonds, have been summarized and discussed. Moreover, the challenges and further opportunities in this area have also been discussed.

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