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Microstructures and mechanical properties of laser-directed energy deposited CrCoNi medium-entropy alloy

Rare Metals 2024年第7期43卷 3286-3300页

作者： Wen-Jie Zhao Chang-Yu Liu Peng-Cheng Che Zhi-Liang Ning Hong-Bo Fan Jian-Fei Sun Yong-Jiang Huang Alfonso H.W.Ngan National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of TechnologyHarbin 150001China Space Environment Simulation Research Infrastructure Harbin Institute of TechnologyHarbin 150001China Department of Mechanical Engineering The University of Hong KongHong Kong 999077China

The distinctive intrinsic heat treatment(IHT)originating from cyclic reheating in the laser-directed energy deposition(LDED) has attracted growing attention in recent *** this investigation,simulations and experimental characterizations were performed to examine the impact of IHT on the micros true ture and mechanical properties of LDED-fabricated CrCoNi medium-entropy alloy(MEA).The results show that the intensity of the IHT is proportional to the utilized laser energy density(LED).As the LED increased,significant dynamic recrystallization and grain refinement occurred within the alloy due to the enhanced intensity of ***,the high LED leads to severe hot cracking within the as-built MEA,resulting in inferior *** decreasing LED,the hot cracking was effectively ***,low LED weakened the intensity of IHT and consequently inhibited kinetic conditions of dynamic recrystallization,resulting in a heterogeneous grain structure characterized by multi-scale-sized *** structure provides significant hetero-deformation-induced hardening during plastic deformation,enabling the alloy to have a sustainable work-hardening *** expect that this work will have implications in taking full advantage of the unique IHT of the LDED process to fabricate ME As with excellent metallurgical quality and mechanical performance.

关键词： Intrinsic heat treatment Laser-directed energy deposition CrCoNi MEA Dynamic recrystallization Heterogeneous grain structure

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A 10-Year Dataset of Land Surface Observations for the Semi-Humid Alpine Grassland in the Source Region of the Yellow River

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Advances in Atmospheric Sciences 2025年第6期42卷 1261-1272页

作者： Xianhong MENG Yu ZHANG Lunyu SHANG Shaoying WANG Zhaoguo LI Shihua LYU Yinhuan AO Siqiong LUO Lijuan WEN Lin ZHAO Hao CHEN Di MA Suosuo LI Lele SHU Yingying AN Danrui SHENG Hanlin NIU Mingshan DENG Key Laboratory of Cryospheric Science and Frozen Soil Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China Zoige Plateau Wetland Ecosystem Research Station Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China Plateau Atmosphere and Environment Key Laboratory of Sichuan Province School of Atmospheric SciencesChengdu University of Information TechnologyChengdu 610225China University of Chinese Academy of Sciences Beijing 100049China

The source region of the Yellow River, accounting for over 38% of its total runoff, is a critical catchment area,primarily characterized by alpine grasslands. In 2005, the Maqu land surface processes observational site was established to monitor climate, land surface dynamics, and hydrological variability in this region. Over a 10-year period(2010–19), an extensive observational dataset was compiled, now available to the scientific community. This dataset includes comprehensive details on site characteristics, instrumentation, and data processing methods, covering meteorological and radiative fluxes, energy exchanges, soil moisture dynamics, and heat transfer properties. The dataset is particularly valuable for researchers studying land surface processes, land–atmosphere interactions, and climate modeling, and may also benefit ecological, hydrological, and water resource studies. The report ends with a discussion on perspectives and challenges of continued observational monitoring in this region, focusing on issues such as cryosphere influences, complex topography,and ecological changes like the encroachment of weeds and scrubland.

关键词： field observation dataset land surface processes alpine grassland energy and water exchanges Yellow River source region Tibetan Plateau

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Low-temperature curing polyimide composites with low coefficient of thermal expansion for high-temperature electronic packaging

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Nano Research 2025年第5期18卷 649-658页

作者： Tianqi Hou Chuan He Ying Lin Yushun Zhao Lijian Ding School of Electrical Engineering and Automation Hefei University of TechnologyHefei 230009China Anhui Province Key Laboratory of Semiconductor Packaging and Reliability Hefei 230009China

Polymer materials with a wide range of applicable temperatures,excellent dielectric properties,and high reliability under complex operating conditions are imperative for packaging applications of next-generation power ***,conventional polyimides(PI)typically require thermal imidization at higher temperatures,which inevitably causes irreversible damage to the solder and other *** this end,this article proposes a feasible strategy that involves the introduction of low-temperature catalyst-modified nanofillers into polyamic *** approach utilizes the nucleophilic attack behavior of the catalyst along with the stacking effect of polymer segments to construct ordered,stable,and high-performance polyimide composite networks at low *** catalyst aminoquinoline(AQL)compensated for the unformed polymer network at low temperatures,while rectorite(REC)nanosheets restricted the molecular chain movement and improved the PI electro-thermal *** results show that with the addition of only 3.0 wt.%of QL-REC,the PI composites can achieve 97.5%imidization at 190℃and possess low dielectric constant(3.2@1 MHz),matched thermal expansion coefficient(24.4 ppm·℃^(−1))and high breakdown strength(361.9 kV·mm^(−1)).Furthermore,the comprehensive nature of the PI composites enables them to meet the packaging requirements for SiC-oriented *** work provides new inspiration for the development of polymeric materials for advanced electronic packaging applications.

关键词： polymer materials polyimide rectorite nanosheets electronic packaging

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High-performance envelope for low-carbon buildings

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Building Simulation 2023年第12期16卷 2207-2209页

作者： Peng Xue Rongpeng Zhang Yuanda Cheng Beijing Key Laboratory of Green Building Environment and Energy Saving Technology Beijing University of TechnologyBeijingChina School of Architecture and Planning Hunan UniversityChangshaChina College of Civil Engineering Taiyuan University of TechnologyTaiyuanChina

The building sector accounts for approximately 40%of global energy consumption and is responsible for about one-third of total greenhouse gas emissions *** the growing emphasis on achieving“Carbon Neutral”targets,there is an urgent demand to advance high-performance buildings that exhibit lower direct and indirect carbon *** this purpose,there is a rising research focus on enhancing high-performance building envelopes,aiming to make a more substantial contribution to the reduction of greenhouse gas emissions and enhance the energy flexibility of buildings while upholding high indoor environmental quality.

关键词： annually performance carbon

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Construction of a Cu@hollow TS-1 nanoreactor based on a hierarchical full-spectrum solar light utilization strategy for photothermal synergistic artificial photosynthesis

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Carbon Energy 2024年第2期6卷 25-36页

作者： Sixian Zhu Qiao Zhao Hongxia Guo Li Liu Xiao Wang Xiwei Qi Xianguang Meng Wenquan Cui Hebei Key Laboratory for Environment Photocatalytic and Electrocatalytic Materials College of Chemical EngineeringNorth China University of Science and TechnologyTangshanChina School of Materials Science and Engineering National Institute for Advanced MaterialsTKL of Metal and Molecule-Based Material ChemistryNankai UniversityTianjinChina Hebei Iron and Steel Laboratory TangshanChina

The artificial photosynthesis technology has been recognized as a promising solution for CO_(2) *** catalysis has been proposed as a novel strategy to promote the efficiency of artificial photosynthesis by coupling both photochemistry and ***,strategies for maximizing the use of solar spectra with different frequencies in photothermal catalysis are urgently ***,a hierarchical full-spectrum solar light utilization strategy is *** on this strategy,a Cu@hollow titanium silicalite-1 zeolite(TS-1)nanoreactor with spatially separated photo/thermal catalytic sites is designed to realize high-efficiency photothermal catalytic artificial *** space-time yield of alcohol products over the optimal catalyst reached 64.4μmol g−1 h−1,with the selectivity of CH3CH2OH of 69.5%.This rationally designed hierarchical utilization strategy for solar light can be summarized as follows:(1)high-energy ultraviolet light is utilized to drive the initial and difficult CO_(2) activation step on the TS-1 shell;(2)visible light can induce the localized surface plasmon resonance effect on plasmonic Cu to generate hot electrons for H2O dissociation and subsequent reaction steps;and(3)low-energy near-infrared light is converted into heat by the simulated greenhouse effect by cavities to accelerate the carrier *** work provides some scientific and experimental bases for research on novel,highly efficient photothermal catalysts for artificial photosynthesis.

关键词： artificial photosynthesis full spectrum nanoreactors photothermal catalysis

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Analyzing the surface passivity effect of germanium oxynitride:a comprehensive approach through first principles simulation and interface state density

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Nuclear Science and Techniques 2024年第5期35卷 74-84页

作者： Sheng-Jie Du Xiu-Xia Li Yang Tian Yuan-Yuan Liu Ke Jia Zhong-Zheng Tang Jian-Ping Cheng Zhi Deng Yu-Lan Li Zheng-Cao Li Sha-Sha Lv College of Nuclear Science and Technology Joint Laboratory of Jinping Ultra‑Low Radiation Background Measurement of Ministry of Ecology and Environment Key Laboratory of Beam Technology of Ministry of Education Beijing Normal UniversityBeijing Normal UniversityBeijing 100875China Joint Research Center Nuctech Company LimitedBeijing 100084China Department of Engineering Physics Key Laboratory of Particle&Radiation Imaging of Ministry of EducationTsinghua UniversityBeijing 100084China Key Laboratory of Advanced Materials(MOE) School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

High-purity germanium(HPGe)detectors,which are used for direct dark matter detection,have the advantages of a low threshold and excellent energy *** surface passivation of HPGe has become crucial for achieving an extremely low energy *** this study,first-principles simulations,passivation film preparation,and metal oxide semiconductor(MOS)capacitor characterization were combined to study surface *** calculations of the energy band structure of the -H,-OH,and -NH_(2) passivation groups on the surface of Ge were performed,and the interface state density and potential with five different passivation groups with N/O atomic ratios were accurately analyzed to obtain a stable surface *** on the theoretical calculation results,the surface passivation layers of the Ge_(2)ON_(2) film were prepared via magnetron sputtering in accordance with the optimum atomic ratio *** microstructure,C-V,and I-V electrical properties of the layers,and the passivation effect of the Al/Ge_(2)ON_(2)/Ge MOS were characterized to test the interface state *** mean interface state density obtained by the Terman method was 8.4×10^(11) cm^(-2) eV^(-1).The processing of germanium oxynitrogen passivation films is expected to be used in direct dark matter detection of the HPGe detector surface passivation technology to reduce the detector leakage currents.

关键词： Surface passivation High purity germanium detector Germanium nitrogen oxide Interface state density

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Co-evolution and correlation mechanism of optical and mechanical properties of (Y0.25Gd0.25Lu0.25Sc0.25)2-2 xTm2xO3 high-entropy transparent ceramics

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Ceramics International 2025年第15期51卷 20316-20323页

作者： Wang, Bin Hao, Yan Luo, Yongzhi Jia, Zhuoying Xiao, Chao Zhang, Wenlong Yu, Shengquan Institute of Chemical Materials China Academy of Engineering Physics Mianyang621900 China State Key Laboratory of Environment-friendly Energy Materials Southwest University of Science and Technology Sichuan Mianyang621010 China

In this study, a highly transparent (Y0.25Gd0.25Lu0.25Sc0.25)2-2xTm2xO3 high-entropy ceramic was prepared by vacuum sintering, and the effect of Tm2O3 was systematically investigated. The ceramic has a single-phase solid solution with the cubic crystal structure of Y2O3, and Tm2O3 promotes grain growth along with densification, the average grain size grows from 5.25 to 16.41 μm, and the transmittance can be significantly increased to 81 % at 5.29 μm, and the hardness of the ceramic reaches 10.76 ± 0.17 GPa. Due to its excellent transmittance at 2–7 μm and good mechanical properties, it has potential applications in medium-wave atmospheric windows. © 2025

关键词： Grain growth

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Boosting singlet oxygen generation for salinity wastewater treatment through co-activation of oxygen and peroxymonosulfate in photoelectrochemical process

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Fundamental Research 2025年第1期5卷 165-173页

作者： Qianqian Yang Zhiyuan Feng Yanbo Zhou Hongying Zhao Guohua Zhao Shanghai Key Lab of Chemical Assessment and Sustainability Key Laboratory of Yangtze River Water EnvironmentSchool of Chemical Science and EngineeringTongji UniversityShanghai 200092China Key Laboratory of Coal Gasification and Energy Chemical Engineering of Ministry of Education East China University of Science and TechnologyShanghai 200092China

High concentrations of inorganic ions in saline wastewater pose adverse effects on hydroxyl radical(HO•)-dominated ***,we report a unique strategy for boosting singlet oxygen(^(1)O_(2))generation via coactivation of oxygen and peroxymonosulfate(PMS)by regulating the electron transfer regime in the photoelectrochemical *** Fe-N bridge in atomic Fe-modified graphitic carbon nitride(denoted SA-FeCN)favors the construction of electron-defective Fe and electron-rich N vacancies(Nvs)to accelerate directional electron *** produced intermediate(HSO_(4-)O···Fe−Nvs···O-O)as a chemical channel accelerates the directional electron transfer from PMS to further reduce O_(2)to form activated products(SO_(5)^(•−),O_(2)^(•−)),thereby transforming O_(2)into^(1)O_(2).An optimized^(1)O_(2)generation rate of 39.4μmol L^(−1)s^(−1)is obtained,which is 15.7–945.0 times higher than that in traditional advanced oxidation *** kinetics are achieved for removing various phenolic pollutants in a nonradical oxidation pathway,which is less susceptible to the coexistence of natural organic matter and inorganic *** COD removal for coal wastewater and complex industrial wastewater in real scenarios is found to reach a value of 90%-96%in 3 *** work provides a new direction for boosting the 1O2 generation rate,especially for the selective degradation of target electron-rich contaminants in saline wastewater.

关键词： Photoelectrochemical process Singlet oxygen Oxygen activation Peroxymonosulfate activation Electron transfer Saline wastewater

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Pore-structure and damage behaviors of cement stone subjected to dry‒wet cycles

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Journal of Rock Mechanics and Geotechnical engineering 2024年第12期16卷 4944-4954页

作者： Xiaoran Li Qiang Sun Jishi Geng Yuliang Zhang Jianjun Hu College of Geology and Environment Xi’an University of Science and TechnologyXi’an710054China Shaanxi Provincial Key Laboratory of Geological Support for Coal Green Exploitation Xi’an710054China Key Laboratory of Coal Resources Exploration and Comprehensive Utilization Ministry of Land and ResourcesXi’an710054China School of Civil and Transportation Engineering Hebei University of TechnologyTianjin300401China State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering College of Civil and Transportation EngineeringShenzhen UniversityShenzhen518060China Jiangxi Key Laboratory of Solar Optoelectronic Materials Nanchang Institute of TechnologyNanchang330044China

The stable protection of the walls of high-temperature geothermal wells is a challenging issue for sustainably exploiting geothermal ***,the cement stone filling layer of the cemented portion of the well deteriorates gradually during geothermal mining due to the dry-wet cycles of the saline geothermal water,reducing the service life of the geothermal *** this,this paper presented five groups of cement stone cylinders with salt contents of 0%,1%,6%,and 11%,which were subjected to heating to 300C and 1e5 dry-wet *** magnetic resonance(NMR)and nonmetallic detection were used to test and analyze the porosity and wave ***,the damage evolution induced by dry-wet cycles was captured based on acoustic emission(AE)*** experimental results indicated that the heating process primarily resulted in mineral and salt crystal expansion,which in turn caused *** damage threshold due to the salt content was found to be 6%.The sudden increase in the thermal stress caused by cooling and deterioration of the tensile strength of the cement column were the key factors in the damage during the cooling *** the number of cycles increased,the accumulated AE energy moved forward and backward,with decreasing and increasing temperature,*** threshold of signal mutation in the heating process is 200C,and the accumulated AE energy decreases by 11.7%.When the salt content was 0%,1%,6%and 11%,the wave velocity decreased by 19%,27.3%,35.5%and 35.9%,*** study also proposed a damage model,which could provide theoretical support for long-term health monitoring and safety protection of geothermal wells.

关键词： Cement stone Dry-water cycle Porosity Wave velocity Fatigue damage

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Deciphering decadal urban ozone trends from historical records since 1980

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National Science Review 2024年第11期11卷 117-129页

作者： Haolin Wang Xiao Lu Paul I.Palmer Lin Zhang Keding Lu Ke Li Tatsuya Nagashima Ja-Ho Koo Hiroshi Tanimoto Haichao Wang Meng Gao Cheng He Kai Wu Shaojia Fan Yuanhang Zhang School of Atmospheric Sciences Sun Yat-sen University and Key Laboratory of Tropical Atmosphere-Ocean System Ministry of Education Guangdong Provincial Observation and Research Station for Climate Environment and Air Quality Change in the Pearl River Estuary Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) School of Geo Sciences University of Edinburgh National Centre for Earth Observation University of Edinburgh Laboratory for Climate and Ocean-Atmosphere Studies Department of Atmospheric and Oceanic SciencesSchool of PhysicsPeking University State Key Joint Laboratory of Environmental Simulation and Pollution Control The State Environmental Protection Key Laboratory of Atmospheric Ozone Pollution ControlCollege of Environmental Sciences and Engineering Peking University Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control Collaborative Innovation Center of Atmospheric Environment and Equipment Technology School of Environmental Science and Engineering Nanjing University of Information Science &Technology National Institute for Environmental Studies Department of Atmospheric Sciences Yonsei University Department of Geography Hong Kong Baptist University Department of Civil and Environmental Engineering University of California

Ozone pollution is a major environmental threat to human health. Timely assessment of ozone trends is crucial for informing environmental policy. Here we show that for the most recent decade（2013–2022） in the northern hemisphere, warm-season（April–September） mean daily 8-h average maximum ozone increases much faster in urban regions with top ozone levels(mainly in the North China Plain, 1.2 ± 1.3 ppbv year-1) than in other, low-ozone regions(0.2 ± 0.9 ppbv year-1). These trends widen the ozone differences across urban regions, and increase extreme pollution levels and health threats from a global perspective. Comparison of historical trends in different urban regions reveals that ozone increases in China during 2013–2022 differ in magnitude and mechanisms to historical periods in other regions since *** reflects a unique chemical environment characterized by exceptionally high nitrogen oxides and aerosol concentrations, where reducing ozone precursor emissions leads to substantial ozone *** increase in China has slowed down in 2018–2022 compared to 2013–2017, driven by ongoing emission reductions, but with ozone-favorable weather conditions. Historical ozone evolution in Japan and South Korea indicates that ozone increases should be suppressed with continuous emission *** temperature and associated wildfires have also reversed ozone decreases in the USA and Europe,with anthropogenic ozone control slowing down in recent decades.

关键词： air quality surface ozone trends

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