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Environment-friendly Ca2+/Cr3+co-doping LaAlO3 ceramics with excellent infrared radiation performance for energy-saving

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JOURNAL OF ADVANCED CERAMICS 2025年第1期14卷 205-214页

作者： Yuan, Xinglai Wang, Qinghu Wu, Runke Sang, Shaobai Xu, Yibiao Liang, Xiong Pan, Liping Fan, Bingbing Li, Yawei Zhang, Rui Li, Jiangtao Volkova, Olena Wuhan univ sci & technol State Key Lab Refractories & Met Joint Int Res Lab Refractories & Met Wuhan 430081 Peoples R China Zhengzhou univ Sch Mat Sci & Engn Zhengzhou 450001 Peoples R China Henan Acad sci Inst Adv Ceram Zhengzhou 450046 Peoples R China Chinese Acad sci Tech Inst Phys & Chem Beijing 100190 Peoples R China TU Bergakad Freiberg Inst Iron & Steel Technol D-09599 Freiberg Germany

Ca2+/Cr3+ co-doped LaAlO3 infrared (IR) ceramics have been proven to be potential energy-saving materials for high- temperature industries because of their high emissivity and high- temperature stability. However, Cr6+ formation commonly occurs in materials and poses environmental and health risks, such as Cr6+ dissolution in water and CrO3(g) volatilization. In this study, we combined high emissivity with in situ detoxification by introducing residual Al2O3 into Ca2+/Cr3+ co-doped LaAlO3 ceramics. Compared with the undoped ceramics, the addition of 20 wt% residual Al2O3 resulted in a 78.5% reduction to 18.44 mg/kg (lower than the EU standard of 20 mg/kg) in Cr6+ dissolution and a decrease in 77.8% CrO3(g) volatilization. This significant detoxification effect can be attributed to the formation of CaAl12-xCrxO19. Additionally, as the residual Al2O3 content increased from 5 to 20 wt%, the ceramics maintained high emissivity, above 0.896 in the near-infrared band and 0.781 in the mid-infrared band. Furthermore, the IR coating effectively increased the surface temperature (from 767.1 to 790.7 degrees C/min) and the heat radiation of the heating source, increasing the heating rate from 31.7 to 34.6 degrees C/min during water heating. This work offers a promising approach for designing environmentally friendly IR ceramics with excellent IR performance for energy-saving applications in the high-temperature industry.

关键词： infrared (IR) radiation energy-saving environmentally friendly Cr6+suppression LaAlO3

Unveiling urbanization effects on trees outside forests along the urban-rural gradient in megacity Bengaluru

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FOREST ECOSYSTEMS 2025年第1期12卷 56-65页

作者： Jiang, Tao Freudenberg, Maximilian Kleinn, Christoph Tewari, V. P. Diwakara, B. N. Noelke, Nils univ Gottingen Fac Forest Sci & Forest Ecol Forest Inventory & Remote Sensing Dept Gottingen Germany ICFRE Himalayan Forest Res Inst Shimla India IWST Inst Wood Sci & Technol Bengaluru India

Rapid urbanization has caused significant changes along the urban-rural gradient, leading to a variety of landscapes that are mainly shaped by human activities. This dynamic interplay also influences the distribution and characteristics of trees outside forests (TOF). Understanding the pattern of these trees will support informed decision-making in urban planning, in conservation strategies, and altogether in sustainable land management practices in the urban context. In this study, we employed a deep learning-based object detection model and high resolution satellite imagery to identify 1.3 million trees with bounding boxes within a 250 km2 research transect spanning the urban-rural gradient of Bengaluru, a megacity in Southern India. Additionally, we developed an allometric equation to estimate diameter at breast height (DBH) from the tree crown diameter (CD) derived from the detected bounding boxes. Our study focused on analyzing variations in tree density and tree size along this gradient. The findings revealed distinct patterns: the urban domain displayed larger tree crown diameters (mean: 8.87 m) and DBH (mean: 43.78 cm) but having relatively low tree density (32 trees per hectare). Furthermore, with increasing distance from the city center, tree density increased, while the mean tree crown diameter and mean tree basal area decreased, showing clear differences of tree density and size between the urban and rural domains in Bengaluru. This study offers an efficient methodology that helps generating instructive insights into the dynamics of TOF along the urban-rural gradient. This may inform urban planning and management strategies for enhancing green infrastructure and biodiversity conservation in rapidly urbanizing cities like Bengaluru.

关键词： Individual tree detection Urbanization Tree density Tree crown diameter

Excellent high-temperature strength of (HfZrTiTaNb)C high-entropy carbide diffusion-bonded joint via in-situ alloying of Ni/Nb/Ni composite interlayer

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JOURNAL OF ADVANCED CERAMICS 2025年第1期14卷 127-133,136-139页

作者： Mu, Ruijie Wang, Ying Niu, Shiyu Sun, Kongbo Yang, Zhenwen Tianjin univ Sch Mat Sci & Engn Tianjin Key Lab Adv Joining Technol Tianjin 300350 Peoples R China Minist Educ Key Lab Adv Ceram & Machining Technol Tianjin 300350 Peoples R China

To obtain high-entropy carbide (HEC) joints with excellent high-temperature performance, a (HfZrTiTaNb)C HEC joint featuring a direct diffusion-bonded interface with a Nb-based interlayer was successfully fabricated at relatively low temperatures of 1150-1250 degrees C for 60 min under 10 MPa. Starting from a modified Ni/Nb/Ni composite interlayer with a Nb content of > 64 at%, an alloyed Nb2Ni layer was constructed in situ by accelerating the directional diffusion of Ni atoms from the high-entropy interface into the remaining pure Nb through the Ni-Nb eutectic liquid. Moreover, the excess liquid phase was squeezed out of the bonding region, ensuring the absence of Ni-based compounds. Leveraging the intrinsic interfacial stability and sluggish diffusion effect, the HEC with its original lattice structure, was capable of developing diffusion bonding with the Nb2Ni layer instead of interacting with the liquid phase. The high reliability of the HEC/Nb2Ni bonded interface was confirmed by the coherence of (1 3) (HEC)// (141) (Nb2Ni) and a calculated lattice misfit of 0.044. The HEC joint had a high room-temperature strength of 174 MPa because of the homogenous Nb2Ni layer, which exhibited nanohardness (15.2 +/- 1.5 GPa) and an elastic modulus of 219.9 +/- 17.5 GPa. Furthermore, the strength of the HEC joint did not decrease at 1000 degrees C, increasing by similar to 49% over that of HEC/Ni/HEC diffusion-bonded joints, which have stringent surface flatness requirements. This suggested that the HEC/Nb2Ni interface had excellent resistance to high-temperature softening, even though it was invariably the initial failure location. This work is informative for designing bonding structures and preparing HEC components.

关键词： high-entropy ceramic diffusion bonding in situ alloyed interlayer mechanical properties

Droughts and windstorms due to climate change increase variability in species and trait composition of a subtropical monsoon evergreen broadleaf forest in China

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FOREST ECOSYSTEMS 2025年第1期12卷 11-19页

作者： Chen, Wenjing Liu, Lei Liu, Daijun Penuelas, Josep Zhou, Guoyi Yu, Zhen Wu, Anchi Wu, Zhurong Hua, Langqin Nanjing univ Informat sci & technol Sch Ecol & Appl Meteorol Nanjing 210044 Peoples R China univ Vienna Dept Bot & Biodivers Res Rennweg 14 A-1030 Vienna Austria CSIC Global Ecol Unit CREAF UAB Barcelona 08193 Catalonia Spain CREAF Barcelona 08193 Catalonia Spain Nanjing univ Informat sci & technol Inst Ecol Sch Ecol & Appl Meteorol Nanjing 210044 Peoples R China Nanjing univ Informat sci & technol Key Lab Ecosyst Carbon Source & Sink China Meteorol Adm ECSS CMA Nanjing 210044 Peoples R China Hubei Minzu univ Hubei Key Lab Biol Resources Protect & Utilizat Enshi 445000 Peoples R China

Background Climate change is accelerating alterations in forest species and community composition worldwide, especially following extreme events like severe droughts and windstorms. Understanding these effects on subtropical forests is crucial for conservation and forest management, but it remains unclear whether the impacts are stochastic or deterministic. Methods We analyzed a unique dataset from a 1-ha permanent plot in a subtropical monsoon broadleaf evergreen forest in China, monitored over 26 years with six surveys from 1994 to 2020. The forest has been free from anthropogenic disturbances for over 400 years. In each survey, we measured all trees with a diameter at breast height (DBH) >= 1 cm, and recorded 11 plant functional traits relating to photosynthesis, wood properties, water use, and nutrient dynamics. Using this data, we calculated species and trait dispersion, assessing short-term (similar to 5 years) and long-term (26 years) trends in species and trait composition following severe droughts and windstorm events. Results Severe droughts, and subsequent droughts, increased both species and trait dispersion, while species composition converged, and trait dispersion remained relatively stable throughout the recovery period. Windstorm events led to increased species dispersion but decreased trait dispersion. We observed a clear directional shift in both species and trait composition under these climatic stressors, with a more pronounced increase in trait dispersion compared to species dispersion. Conclusion In the short term (similar to 5 years), severe droughts and windstorms increased species composition divergence, while trait composition responses varied. Over 26 years, deterministic processes mainly drove community composition changes, especially for trait composition, although stochastic processes also played a role. These findings suggest enhancing forest resilience to climatic stressors by protecting adaptive species or increasing species diversit

关键词： Community dynamics Functional traits Community composition Deterministic processes Climate change

Is p-Type Doping in SeO₂ Feasible?

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CHINESE PHYSICS LETTERS 2025年第2期42卷 72-77页

作者： Xiao, Zewen Huazhong univ sci & technol Wuhan Natl Lab Optoelect Wuhan 430074 Peoples R China

p-type transparent oxide semiconductors (TOSs) are significant in the semiconductor industry, driving advancements in optoelectronic technologies for transparent electronic devices with unique properties. The recent discovery of p-type behavior in SeO2 has stimulated interest and confusion in the scientific community. In this Letter, we employ density functional theory calculations to reveal the intrinsic intrinsic insulating characteristics of SeO2 and highlight the substantial challenges in carrier doping. Our electronic structure analyses indicate that the Se 5s2 states are energetically positioned too low to effectively interact with the O 2p orbitals, resulting in a valence band maximum (VBM) primarily dominated by the O 2p orbitals. The deep and localized nature of the VBM of SeO2 limits its potential as a high-mobility p-type TOS. Defect calculations demonstrate that all intrinsic defects in SeO2 exhibit deep transition levels within the bandgap. Regardless of the synthesis conditions, the Fermi level consistently resides in the mid-gap region. Furthermore, deep intrinsic acceptors and donors exhibit negative formation energies in the n-type and p-type regions, respectively, facilitating spontaneous formation and impeding external doping efforts. Thus, the reported p-type conductivity in SeO2 samples is unlikely to be intrinsic and is more plausibly attributable to reduced elemental Se, a well-known p-type semiconductor.

关键词： Semiconductor device manufacture

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： Yang, Qianqian Feng, Zhiyuan Zhou, Yanbo Zhao, Hongying Zhao, Guohua Tongji univ Sch Chem Sci & Engn Key Lab Yangtze River Water Environm Shanghai Key Lab Chem Assessment & Sustainabil Shanghai 200092 Peoples R China East China univ sci & technol Minist Educ Key Lab Coal Gasificat & Energy Chem Engn Shanghai 200092 Peoples R China

High concentrations of inorganic ions in saline wastewater pose adverse effects on hydroxyl radical (HO' )dominated technologies. Here, we report a unique strategy for boosting singlet oxygen (1 O2 ) generation via coactivation of oxygen and peroxymonosulfate (PMS) by regulating the electron transfer regime in the photoelectrochemical process. The 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 transfer. The produced intermediate (HSO4-O center dot center dot center dot Fe- Nvs center dot center dot center dot O-O) as a chemical channel accelerates the directional electron transfer from PMS to further reduce O2 to form activated products (SO5'-, O2'-), thereby transforming O2 into 1 O2 . An optimized 1 O2 generation rate of 39.4 mu mol L-1s- 1 is obtained, which is 15.7-945.0 times higher than that in traditional advanced oxidation processes. Fast 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 ions. The COD removal for coal wastewater and complex industrial wastewater in real scenarios is found to reach a value of 90%-96% in 3 h. This work provides a new direction for boosting the 1 O2 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

Precise spectroscopy of metastable Li plus using the optical Ramsey technique in support of time dilation tests

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PHOTONICS RESEARCH 2025年第1期13卷 201-209页

作者： Zhou, Peng-peng Chen, Shao-long Qin, Cheng-gang Chang, Xu-rui Zhou, Zhi-qiang Sun, Wei Huang, Yao Gao, Ke-lin Guan, Hua Chinese Acad sci Innovat Acad Precis Measurement Sci & Technol State Key Lab Magnet Resonance & Atom & Mol Phys Wuhan 430071 Peoples R China Informat Engn univ Zhengzhou 450001 Peoples R China Chinese Acad sci Key Lab Time Reference & Applicat Wuhan 430206 Peoples R China Huazhong univ sci & technol MOE Key Lab Fundamental Phys Quant Measurement Wuhan 430074 Peoples R China Huazhong univ sci & technol Hubei Key Lab Gravitat & Quantum Phys PGMF Wuhan 430074 Peoples R China Huazhong univ sci & technol Sch Phys Wuhan 430074 Peoples R China univ Chinese Acad sci Beijing 100049 Peoples R China Chinese Acad sci Qinghai Inst Salt Lakes Key Lab Green & High end Utilizat Salt Lake Resour Xining 810008 Peoples R China Wuhan Inst Quantum technol Wuhan 430206 Peoples R China

Time dilation constitutes a crucial aspect of Lorentz invariance within special relativity and undergoes constant scrutiny through numerous Ives-Stilwell-type experiments employing the Doppler effect. In our study, we employed optical Ramsey spectroscopy on a Li+ ion beam to enhance the precision of measuring the intrinsic transition frequency 23S1 - 23P2 to the level of four parts in 1010 with speed of 0.00035c. Our findings reconciled an existing 2 MHz disparity between collinear and perpendicular laser spectroscopy. Furthermore, in conjunction with previous studies on Li+ ion beams traveling at speeds of 0.064c and 0.338c [Nat. Phys. 3, 861 (2007);Phys. Rev. Lett. 113, 120405 (2014)], we updated the Robertson-Mansouri-Sexl parameter alpha to be (-10.0 f 9.9) x 10-8 and (-2.9 f 2.0) x 10-8, respectively. (c) 2024 Chinese Laser Press

关键词： Doppler effect Frequency combs Laser beams Nodal aberration theory Optical clocks Optical fields

Tree growth decline to warm-wet conditions in boreal forests is linked to stand density

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FOREST ECOSYSTEMS 2025年第1期12卷 74-82页

作者： Zhao, Bingqian Zhu, Yihong Gao, Lushuang Zhang, Qibing Liu, Mingqian von Gadow, Klaus Beijing Forestry univ Res Ctr Forest Management Engn State Forestry Grassland Adm Beijing 100083 Peoples R China Beijing Forestry univ State Forestry & Grassland Adm Key Lab Forest Reso Beijing 100083 Peoples R China univ Calif Berkeley Dept Environm Sci Policy & Management Berkeley CA 94704 USA Chinese Acad sci Inst Bot State Key Lab Vegetat & Environm Change Beijing 100093 Peoples R China univ Ghent Lab Wood Technol Coupure links 653 B-9000 Ghent Belgium Georg August univ Gottingen Fac Forestry & Forest Ecol Busgenweg 5 D-37077 Gottingen Germany Stellenbosch univ Fac Agrisci Dept Forestry & Wood Sci Stellenbosch Private Bag X1 ZA-7602 Stellenbosch South Africa

Warm-wet climatic conditions are widely regarded as conducive to remarkable tree growth, alleviating climatic pressures. However, the notable decline in tree growth observed in the southern edge of boreal forests has heightened concerns over the spatial-temporal dynamics of forest decline. Currently, attaining a comprehensive grasp of the underlying patterns and their propelling factors remains a formidable challenge. We collected tree ring samples from a network of 50 sites across the Greater Xing'an Mountains. These samples were subsequently grouped into two distinct clusters, designated as Groups A and B. The percentage change of growth (GC, %) and the proportion of declining sites were utilized to assess forest decline. The decline in tree growth within Larix gmelinii forests exhibits significant regional variation, accompanied by temporal fluctuations even within a given region. Group A exhibited a pronounced increase in frequency (59.26%) of occurrences and encountered more severe declines (21.65%) in tree growth subsequent to the 1990s, contrasting sharply with Group B, which observed lower frequencies (20.00%) and relatively less severe declines (21.02%) prior to the 1980s. The primary impetus underlying the opposite radial growth increments observed in Larix gmelinii trees from the interplay between their differential response to temperatures and wetter climatic conditions, which is significantly influenced by varying stand densities. In cold-dry conditions, low-density forests may experience soil water freezing, exacerbating drought conditions and thereby inhibiting tree growth, in Group B. Trees growth in high-density stands is restrained by warm-wet conditions, in Group A. These results provide new insights into the variability at the southern edge of the boreal forest biome with different responses to density and climate.

关键词： Growth decline Stand density The southern edge of boreal forests Larix gmelinii

Layered metal carbo-selenide Nb2CSe2 with van der Waals interlayer coupling

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JOURNAL OF ADVANCED CERAMICS 2025年第1期14卷 101-110页

作者： Wang, Junchao Cheng, Renfei Hu, Tao Tang, Xinyue Liang, Yan Tian, Min Xiong, Ting Lu, Qiuhong Zhu, Qi Yang, Zhiqing Wang, Xiaohui Zhou, Yanchun Chinese Acad sci Inst Met Res Shenyang Natl Lab Mat Sci Shenyang 110016 Peoples R China univ sci & technol China Sch Mat Sci & Engn Shenyang 110016 Peoples R China Suzhou univ sci & technol Inst Mat Sci & Devices Sch Mat Sci & Engn Suzhou 215009 Peoples R China Shenyang Ligong univ Sch Mat Sci & Engn Shenyang 110159 Peoples R China Ji Hua Lab Foshan 528000 Peoples R China Northeastern univ Sch Mat Sci & Engn Key Lab Anisotropy & Texture Mat Minist Educ Shenyang 110819 Peoples R China Zhengzhou univ Sch Mat Sci & Engn Zhengzhou 450001 Peoples R China

The stacking structure of Nb2CSe2, a newly synthesized layered metal carbo-selenide, was elucidated by scanning transmission electron microscopy. Nb2CSe2 features Se-Nb-C-Nb-Se quintuple atomic layers. These layers are stacked in Bernal mode. In this mode, Nb2CSe2 crystallizes in a trigonal symmetry (space group P 3 m 1, No. 164), with lattice parameters of a = 3.33 & Aring;and c = 18.20 & Aring;. Electronic structure calculations indicate that the metal carbo-selenide has Fermi energy crossing the bands where it touches to give a zero gap, indicating that it is an electronic conductor. As evidenced experimentally, the electrical conductivity is as high as 6.6x105 Sm-1, outperforming the counterparts in the MXene family. Owing to the layered structure, the bonding in Nb2CSe2 with an ionic formula of (Nb 1.48+ ) 2 (C 1.74- )(Se 0.61- ) 2 is highly anisotropic, with metallic-covalent-ionic bonding in intralayers and weak bonding between interlayers. The layered nature is further evidenced by elastic properties, interlayer energy, and friction coefficient determination. These characteristics indicate that Nb2CSe2 is an analog of molybdenum disulfide (MoS2), which is a typical binary van der Waals (vdW) solid. Moreover, vibrational properties are reported, which may offer an optical identification standard for new ternary vdW solids in spectroscopic studies, including Raman scattering and infrared absorption.

关键词： MXene Nb2CSe2 crystal structure electronic structure elastic properties interlayer coupling Raman spectroscopy friction coefficient