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Differences and similarities in radial growth of Betula species to climate change

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Journal of Forestry Research 2024年第2期35卷 176-187页

作者： Di Liu Yang An zhao Li Zhihui Wang Yinghui zhao x.aochun Wang Center for Ecological Research Key Laboratory of Sustainable Forest Ecosystem ManagementMinistry of EducationCollege of ForestryNortheast Forestry UniversityHarbin 150040People’s Republic of China Changan Park in Shijiazhuang Shijiazhuang 050000People’s Republic of China Shijiazhuang Landscape Greening Engineering Project Construction Center Shijiazhuang 050000People’s Republic of China Heilongjiang Institute of Meteorological Science Harbin 150030People’s Republic of China School of Life Qufu Normal UniversityQufu 273100People’s Republic of China

Betula platyphylla and Betula costata are important species in mix.d broadleaved-Korean pine(Pinus koraiensis)***,the specific ways in which their growth is affected by warm temperatures and drought remain *** address this issue,60 and 62 tree-ring cores of *** and *** were collected in Yichun,*** dendrochronological methods,the response and adaptation of these species to climate change were ex.mined.A“hysteresis effect”was found in the rings of both species,linked to May–September moisture conditions of the previous *** growth of *** was positively correlated with the standardized precipitation-evapotranspiration index.SPEI),the precipitation from September to October of the previous year,and the relative humidity in October of the previous *** of *** is primarily restricted by moisture conditions from September to *** contrast,*** growth is mainly limited by minimum temperatures in May–June of both the previous and current *** droughts,*** had a faster recovery rate compared to *** the contex. of rising temperatures since 1980,the correlation between *** growth and monthly SPEI became positive and strengthened over time,while the growth of *** showed no conspicuous *** findings suggest that the growth of *** is already affected by warming temperatures,whereas *** may become limited if warming continues or *** change could disrupt the succession of these species,possibly accelerating the succession of pioneer *** results of this research are of great significance for understanding how the growth changes of birch species under warming and drying conditions,and contribute to understanding the structural adaptation of mix.d broadleaved-Korean pine(Pinus koraiensis)forests under climate change.

关键词： Tree rings Betula platyphylla Betula costata Climate response Moving correlation Ex.reme drought

Broadband intelligent programmable metasurface with polarization-modulated self-adaptive electromagnetic functionality switching

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Photonics Research 2024年第7期12卷 1395-1409页

作者： x.MING LI RUI x. x.AOFENG SUN YUAN zhao zhao YANG GUOHONG DU College of Electronic Engineering Chengdu University of Information TechnologyChengdu 610225China

Programmable metasurfaces have received a great deal of attention due to their ability to dynamically manipulate electromagnetic(EM) waves. Despite the rapid growth, most of the ex.sting metasurfaces require manual control to switch among different functionalities, which poses severe limitations on practical applications. Here, we put forth an intelligent metasurface that has self-adaptive EM functionality switching in broadband without human participation. It is equipped with polarization discrimination antennas(PDAs) and feedback components to automatically adjust functionalities for the different incident polarization information.

关键词： equipped adjust polarization

Remarkable enhancement of gas selectivity on organosilica hybrid membranes using urea-modulated metal-organic framework nanoparticles

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Frontiers of Chemical Science and Engineering 2024年第2期18卷 83-92页

作者： Yayun zhao Dechuan zhao Chunlong Kong Yichao Lin x.ezhen Wang Liang Chen Key Laboratory of Advanced Fuel Cells and Electrolyzers Technology of Zhejiang Province Ningbo Institute of Materials Technology and EngineeringChinese Academy of SciencesNingbo 315201China University of Chinese Academy of Sciences Beijing 100049China Collaboration Innovation Center for Tissue Repair Material Engineering Technology China West Normal UniversityNanchong 637009China

Metal-organic framework/organosilica hybrid membranes on tubular ceramic substrates have shown great potential for the implementation of membrane technology in practical gas separation projects due to their higher permeance compared to commercial ***,the selectivities of the reported membranes are ***,we have incorporated urea-modulated metal-organic frameworks into organosilica membranes to greatly enhance its separation *** urea-modulated metal-organic frameworks ex.ibit less-defined edges of crystallographic facets and high defect *** can be well-dispersed in the organosilica layer,which substantially suppresses the interfacial defects between metal-organic frameworks and organosilica,which is beneficial for improving the selectivity of membranes for gas *** results have shown that the enhanced ideal selectivity of H_(2)/CH_(4) was 165 and that of CO_(2)/CH_(4) was 43,with H_(2) permeance of about 1.25×10^(−6) mol·m^(−2)·s^(−1)·Pa^(−1) and CO_(2) permeance of 3.27×10^(−7) mol·m^(−2)·s^(−1)·Pa^(−1) at 0.2 MPa and 25℃.In conclusion,the high level of hybrid membranes can be used to separate H_(2)(or CO_(2))from the binary gas mix.ure H_(2)/CH_(4)(or CO_(2)/CH_(4)),which is important for gas separation in practical ***,the simple and feasible modulation of metal-organic framework is a promising strategy to tune different metal-organic frameworks for membranes according to the actual demands.

关键词： ZIF-8 nanocrystals urea organosilica hybrid membrane enhanced separation performance

Tribological properties of low-temperature time-dependent pretreated graphite for mechanical seal pairs in high-speed turbopump

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Friction 2024年第2期12卷 305-318页

作者： Yangyang zhao Guoyuan ZHANG Junqian WANG He WANG Weigang zhao Qunfeng ZENG School of Mechano-Electronic Engineering Xidian UniversityXi’an 710071China x.’an Aerospace Propulsion Institute Xi’an 710071China Key Laboratory of Education Ministry for Modern Design and Rotor-Bearing System Xi’an Jiaotong UniversityXi’an 710049China

The friction coefficient and wear rate of pretreated graphite with liquid nitrogen were obtained by using a ball-on-disk tester,and the wear of GCr15–graphite seal pairs with the low-temperature time-dependent pretreatment was discussed by comparing the wear *** results show that liquid nitrogen pretreatment can affect the hardness and interlayer spacing of *** range of the friction coefficients of pretreated graphite changes from 0.17 to *** the increase of liquid nitrogen pretreatment time,the wear mechanism of graphite would change from dominated three-body wear to adhesion *** ex.erimental results of the mechanical seal with liquid nitrogen pretreatment show that the wear rate of stator is less than 0.00165 mm^(3)·N^(−1)·m^(−1),and the graphite shows a good low-temperature compatibility.

关键词： graphite low-temperature pretreatment mechanical seal friction and wear

Singularity analysis and avoidance for an SSRMS-type reconfigurable space manipulator with a non-spherical wrist and two lockable passive telescopic links

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Chinese Journal of Aeronautics 2024年第8期37卷 435-459页

作者： Zhiyuan zhao x.aohang YANG Yuntao LI Zichun x. Jingdong zhao Hong LIU State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150001China

This study focuses on addressing kinematic singularity analysis and avoidance issues for a space station remote manipulator system(SSRMS)-type reconfigurable space *** manipulator is equipped with a non-spherical wrist and two lockable passive telescopic links(LPTLs),which enable it to have both active revolute and passive prismatic joints and operate in two distinct *** begin with the kinematic singularity analysis,the study derives the differential kinematic equations for the manipulator and identifies the dominant Jacobian matrix.that causes ***,an in-depth analysis of singularities from multiple perspectives is ***,a kinematic singularity map method is proposed to capture the distribution of singularities within the reachable ***,the influence of the two LPTLs on singularities is thoroughly ***,a new method based on the matrix.rank equivalence principle is introduced to determine singularity conditions,enabling the identification of all the singular configurations for the SSRMS-type reconfigurable ***,this method significantly reduces computational complex.ty,and the singularity conditions obtained have more concise *** the singularity avoidance problem,a novel method is developed,which simultaneously addresses the requirements of real-time performance,high precision,and the avoidance of both kinematic singularities and joint limit *** from these ex.ellent properties,the proposed method can effectively resolve the singularity issues encountered separately by the SSRMS-type reconfigurable manipulator in its two operational *** typical simulations validate the utility of all the proposed methods.

关键词： Reconfigurable space manipulator Redundant manipulator Kinematics Singularity analysis Singularity avoidance

An Environment‑Tolerant Ion‑Conducting Double‑Network Composite Hydrogel for High‑Performance Flex.ble Electronic Devices

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Nano-Micro Letters 2024年第5期16卷 352-369页

作者： Wenchao zhao Haifeng Zhou Wenkang Li Manlin Chen Min Zhou Long zhao State Key Laboratory of Advanced Electromagnetic Technology School of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074People’s Republic of China School of Chemistry and Chemical Engineering Huazhong University of Science and TechnologyWuhan 430074People’s Republic of China

High-performance ion-conducting hydrogels(ICHs)are vital for developing flex.ble electronic ***,the robustness and ion-conducting behavior of ICHs deteriorate at ex.reme tempera-tures,hampering their use in soft *** resolve these issues,a method involving freeze–thawing and ionizing radiation technology is reported herein for synthesizing a novel double-network(DN)ICH based on a poly(ionic liquid)/Mx.ne/poly(vinyl alcohol)(PMP DN ICH)*** well-designed ICH ex.ibits outstanding ionic conductivity(63.89 mS cm^(-1) at 25℃),ex.ellent temperature resistance(-60–80℃),prolonged stability(30 d at ambient temperature),high ox.dation resist-ance,remarkable antibacterial activity,decent mechanical performance,and ***,the ICH performs effectively in a flex.ble wireless strain sensor,thermal sensor,all-solid-state supercapacitor,and single-electrode triboelectric nanogenerator,thereby highlighting its viability in constructing soft electronic *** highly integrated gel structure endows these flex.ble electronic devices with stable,reliable signal output *** particular,the all-solid-state supercapacitor containing the PMP DN ICH electrolyte ex.ibits a high areal specific capacitance of 253.38 mF cm^(-2)(current density,1 mA cm^(-2))and ex.ellent environmental *** study paves the way for the design and fabrication of high-performance mul-tifunctional/flex.ble ICHs for wearable sensing,energy-storage,and energy-harvesting applications.

关键词： Ionic liquids Double-network hydrogels Temperature tolerance Multifunctionality Flex.ble electronic devices

A new gravitational theory and dark matter problem

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Communications in Theoretical Physics 2024年第6期76卷 129-136页

作者： x.ong zhao Yongge Ma Department of Physics Beijing Normal UniversityBeijing 100875China

We propose a new gravitational theory with torsion based on Riemann-Cartan geometry,in which all physical quantities are *** addition to the spacetime metric,the gravitational degrees of freedom in this theory also include the torsion and two scalar *** energy-momentum tensor of the matter fields in this theory is also proposed.A spherically symmetric static vacuum solution of the theory is *** turns out that this solution can fit the observational data of the rotation curve outside the stellar disk in the Milky ***,the galactic dark matter may just be the gravitational effect of the theory with torsion.

关键词： gravity torsion dark matter

New pimarane diterpenoids with antibacterial activity from fungus Arthrinium ***03

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Chinese Journal of Natural Medicines 2024年第4期22卷 356-364页

作者： zhao Songfeng JING Ziwei Department of Pharmacy the First Affiliated Hospital of Zhengzhou UniversityZhengzhou 450052China

A comprehensive chemical study of the endophytic fungus Arthrinium sp. ZS03, associated with Acorus tatarinowii Schott, yielded eleven pimarane diterpenoids (compounds 1–11), including seven novel compounds designated arthrinoids A–G (1–7). The determination of their structures and absolute configurations was achieved through ex.ensive spectroscopic techniques, quantum chemical calculations of electronic circular dichroism (ECD), and single-crystal x.ray diffraction analysis. Furthermore, 7 demonstrated inhibitory activity against Klebsiella pneumoniae, comparable to the reference antibiotic amikacin, with a minimum inhibitory concentration (MIC) of 8 μg·mL^(−1).

关键词： Arthrinium sp.ZS03 Pimarane diterpenoids Structural elucidation Antibacterial activity

Towards catalytic reactions of Cu single-atom catalysts:Recent progress and future perspective

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Chinese Chemical Letters 2024年第2期35卷 197-207页

作者： Yitao zhao Lei Tao Jiangsu Province Engineering Research Center of Special Functional Tex.ile Materials Changzhou Vocational Institute of Textile and GarmentChangzhou 213164China Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology Advanced Catalysis and Green Manufacturing Collaborative Innovation CenterSchool of Petrochemical EngineeringChangzhou UniversityChangzhou 213164China

One of the urgent and challenging topics in diversified sustainable energy conversion is the development of high-performance,low-cost,and well durable *** single-atom catalysts(SACs)have become promising catalysts for diversified sustainable energy conversion due to their capability to max.mize the utilization efficiency,acquire modulated electronic structure and optimized binding strength with *** this review,we have provided an interview of the recent progress achieved in the field of electrocatalysis,photocatalysis,and heterogeneous reaction based on Cu *** by this review,we have summarized some advanced synthetic strategies for the construction of Cu ***,the performance-improving strategies are discussed in terms of the coordination environments of the reaction center,reaction mechanism and selectivity,based on free energy diagram and electron structure ***,the remaining issues,challenges,and opportunities of Cu SACs are also provided,affording a perspective for future *** review not only offers us a deep understanding on the catalytic mechanism of Cu SACs for energy conversion,but also encourages more endeavors in prompting their practical application.

关键词： Cu SACs Energy conversion Catalysis Coordination environment