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A new method of calculating crown projection area and its comparative accuracy with conventional calculations for asymmetric tree crowns

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Journal of Forestry Research 2024年第4期35卷 171-188页

作者： Mingrui Zhang Huiquan bi Xingji Jin Michael McLean School of Forestry Northeast Forestry UniversityHarbin 150040People’s Republic of China Forest Science NSW Department of Primary IndustriesLevel 304PSQ12 Darcy StreetParramattaNSW 2150Australia School of Ecosystem and Forest Sciences The University of MelbourneMelbourne 3010Australia

This paper introduces a new method of calculating crown projection area(CPA),the area of level ground covered by a vertical projection of a tree crown from measured crown radii through numerical interpolation and *** novel method and other four existing methods of calculating CPA were compared using detailed crown radius measurements from 30 tall trees of Eucalyptus pilularis variable in crown size,shape,and *** four existing methods included the polygonal approach and three ways of calculating CPA as the area of a circle using the arithmetic,geometric and quadratic mean *** were made across a sequence of eight non-consecutive numbers(from 2 to 16)of measured crown radii for each tree over the range of crown asymmetry of the 30 trees through generalized linear models and multiple comparisons of *** sequence covered the range of the number of crown radii measured for calculating the CPA of a tree in the literature.A crown asymmetry index within the unit interval was calculated for each tree to serve as a normative *** a slight overestimation of 2.2%on average and an overall mean error size of 7.9%across the numbers of crown radii that were compared,our new method was the least biased and most *** CPA as a circle using the quadratic mean crown radius was the second best,which had an average overestimation of 4.5%and overall mean error size of 8.8%.These two methods remained by and large unbiased as crown asymmetry increased,while the other three methods showed larger bias of *** the conventional method of using the arithmetic mean crown radius to calculate CPA as a circle,bias correction factors were developed as a function of crown asymmetry index to delineate the increasing magnitude of bias associated with greater degrees of crown *** study reveals and demonstrates such relationships between the accuracy of CPA calculations and crown asymmetry and will help increase awa

关键词： Crown radius measurements Interpolated crown contour Projected crown area Multiple comparisons of means

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A Reliable Iteration Algorithm for One-bit Compressive Sensing on the Unit Sphere

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Acta Mathematicae Applicatae Sinica 2024年第3期40卷 801-822页

作者： Yan-cheng LU Ning bi An-hua WAN School of Mathematics Sun Yat-sen UniversityGuangzhou 510275China

The one-bit compressed sensing problem is of fundamental importance in many areas,such as wireless communication,statistics,and so ***,the optimization of one-bit problem coustrained on the unit sphere lacks an algorithm with rigorous mathematical proof of convergence and *** this paper,an iteration algorithm is established based on difference-of-convex algorithm for the one-bit compressed sensing problem constrained on the unit sphere,with iterating formula■,where C is the convex cone generated by the one-bit measurements andη_(1)>η_(2)>1/*** new algorithm is proved to converge as long as the initial point is on the unit sphere and accords with the measurements,and the convergence to the global minimum point of the l_(1)norm is discussed.

关键词： one-bit compressed sensing difference of convex algorithm iteration algorithm ■1-minimization

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On-the-fly precision spectroscopy with a dual-modulated tunable diode laser and Hz-level referencing to a cavity

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Advanced Photonics 2024年第4期6卷 36-44页

作者： Shuangyou Zhang Toby bi Pascal Del’Haye Max Planck Institute for the Science of Light Friedrich-Alexander Universit?t Erlangen-Nürnberg Department of Physics

Advances in laser spectroscopy have enabled many scientific breakthroughs in physics, chemistry,biology, and astronomy. Optical frequency combs pushed measurement limits with ultrahigh-frequency accuracy and fast-measurement speed, while tunable-diode-laser spectroscopy is used in scenarios that require high power and continuous spectral coverage. Despite these advantages of tunable-diode-laser spectroscopy, it is challenging to precisely determine the instantaneous laser frequency because of fluctuations in the scan speed. Here, we demonstrate a simple spectroscopy scheme with a frequencymodulated diode laser that references the laser on-the-fly to a fiber cavity. The fiber cavity's free spectral range is on-the-fly calibrated with sub-10-Hz frequency precision. We achieve a relative precision of the laser frequency of 2 × 10-8for an 11-THz frequency range at a measurement speed of 1 THz∕s. This is an improvement of more than 2 orders of magnitude compared to existing diode-laser-spectroscopy *** scheme provides precise frequency calibration markers, while simultaneously tracking the instantaneous scan speed of the laser. We demonstrate the versatility of our method through various applications, including dispersion measurement of a fiber, ultrahigh-Q microresonators, and spectroscopy of a hydrogen fluoride gas cell. The simplicity, robustness, and low cost of this spectroscopy scheme are valuable for out-of-the-lab applications like lidar and environmental monitoring.

关键词： frequency comb gas spectroscopy integrated photonics radio-frequency modulation tunable laser spectroscopy

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Targeting RAF dimers in RAS mutant tumors:From biology to clinic

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Acta Pharmaceutica Sinica B 2024年第5期14卷 1895-1923页

作者： Huanhuan Yin Qiulin Tang Hongwei Xia Feng bi Division of Abdominal Cancer Department of Medical OncologyCancer Center and Laboratory of Molecular Targeted Therapy in OncologyWest China HospitalSichuan UniversityChengdu 610041China

RAS mutations occur in approximately 30%of tumors worldwide and have a poor prognosis due to limited *** targeting of KRAS G12C has achieved significant success in recent years,but there is still a lack of efficient therapeutic approaches for tumors with non-G12C KRAS mutations.A highly promising approach is to target the MAPK pathway downstream of RAS,with a particular focus on RAF ***-generation RAF inhibitors have been authorized to treat BRAF mutant tumors for over a ***,their use in RAS-mutated tumors is not recommended due to the paradoxical ERK activation mainly caused by RAF *** address the issue of RAF dimerization,type II RAF inhibitors have emerged as leading *** clinical studies have shown the initial effectiveness of these agents against RAS mutant ***,type II RAF inhibitors in combination with MEK or ERK inhibitors have demonstrated impressive efficacy in RAS mutant *** review aims to clarify the importance of RAF dimerization in cellular signaling and resistance to treatment in tumors with RAS mutations,as well as recent progress in therapeutic approaches to address the problem of RAF dimerization in RAS mutant tumors.

关键词： RAS mutations RAF dimerization RAF inhibitors Cancer therapy Drug resistance

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An unexpected approach to enhance specific surface area and mesopore amount of polyaniline by Zn doping

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Rare Metals 2024年第9期43卷 4585-4594页

作者： Zhi-Da Zhu Yu-Zhe Han Xiao-bi Jing School of Mechanical Engineering Yangzhou University School of Chemistry and Chemical Engineering Yangzhou University

Poly-p-anisidine could be easily fabricated via the oxidative polymerization reaction of p-anisidine using H2O2as the green oxidant. It was unexpectedly found that zinc doping could significantly improve the adsorption ability of the material versus heavy metals such as Pb, Cu,Pd, Ag and Hg. Results of nitrogen adsorption–desorption experiments demonstrated that Zn doping could enhance the specific surface area and mesopore amount of the prepared material, which might facilitate its absorption to metals. This work not only provides a novel material for the treatment of heavy metal-polluted water but also leads to a nice mesoporous catalyst support for environment protection and organic synthesis, i.e. the Zn-doped poly-panisidine can be employed as the catalyst support to prepare Cu@PANI-OMe/Zn or Pd@PANI-OMe/Zn for the oxidative degradation reaction of phenol or Suzuki–Miyaura coupling reactions, respectively. It discloses a new strategy for fabricating the mesoporous polyaniline materials with profound application potential.

关键词： Adsorption Catalysis Porous materials Rare metal concentration Surfaces

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Feedback of Efficient Shock Acceleration on Magnetic-field Structure Inside Young Type Ia Supernova Remnants

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Research in Astronomy and Astrophysics 2024年第6期24卷 234-244页

作者： Jun-Yu Shen bi-Wen Bao Li Zhang Department of Astronomy Key Laboratory of Astroparticle Physics of Yunnan ProvinceYunnan UniversityKunming 650091China Key Laboratory of Statistical Modeling and Data Analysis of Yunnan Province Yunnan UniversityKunming 650091China

Using an effective adiabatic index γ_(eff) to mimic the feedback of efficient shock acceleration,we simulate the temporal evolution of a young type Ia supernova remnant (SNR) with two different background magnetic field(BMF) topologies:a uniform and a turbulent *** density distribution and magnetic-field characteristics of our benchmark SNR are studied with two-dimensional cylindrical magnetohydrodynamic *** γ_(eff)is considered,we find that:(1) the two-shock structure shrinks and the downstream magnetic-field orientation is dominated by the Rayleigh–Taylor instability structures;(2) there exists more quasi-radial magnetic fields inside the shocked region;and (3) inside the intershock region,both the quasi-radial magnetic energy density and the total magnetic energy density are enhanced:in the radial direction,with γ_(eff)=1.1,they are amplified about 10–26 times more than those with γ_(eff)=5/*** in the angular direction,the total magnetic energy densities could be amplified about 350 times more than those with γ_(eff)=5/3,and there are more grid cells within the intershock region where the magnetic energy density is amplified by a factor greater than 100.

关键词： methods:numerical ISM:magnetic fields ISM:supernova remnants magnetohydrodynamics(MHD)

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Characterization and Analysis of Inconel 718 Alloy Ground at Different Speeds

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Chinese Journal of Mechanical Engineering 2024年第2期37卷 137-149页

作者： Hao Liu Huili Han Qinghong Jiang Minglin He bi Zhang Department of Mechanical and Energy Engineering Southern University of Science and TechnologyShenzhen 518055China Department of Mechanical Engineering Hong Kong Polytechnic UniversityHong KongChina

Inconel 718(IN718)alloy is widely applied to fabricate high temperature resistant or corrosion resistant parts due to its excellent mechanical ***,the machining of IN718 alloy is difficult as it may cause serious tool wear and poor surface quality(SQ)of the *** this work,grinding experiments on IN718 alloy at different speeds were conducted by using a CBN grinding *** relationship between grinding speed,SQ and subsurface damage(SSD)was well *** increasing grinding speed,surface roughness decreased,and SQ was greatly ***,the microhardness of the grinding surface declined as the grinding speed *** SSD depth was almost unchanged when the grinding speed was lower than 15 m/s,then it decreased with higher grinding *** was attributed to the mechanical-thermal synergistic effect in the grinding *** results indicated that increasing grinding speed can effectively improve the SQ and reduce the SSD of IN718 *** conclusion in the work may also provide insight into processing other hard-to-machining materials.

关键词： Surface integrity Grinding speed IN718 alloy Precision machining CBN grinding wheel

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Recent Advances in Deciphering the Mechanisms and biological Functions of DNA Demethylation

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Chinese Journal of Chemistry 2024年第6期42卷 645-651页

作者： Yang Feng Sheng-Jun Chen bi-Feng Yuan Key Laboratory of Aquatic Product Processing Ministry of Agriculture and Rural AffairsNational R&D Center for Aquatic Product ProcessingSouth China Sea Fisheries Research InstituteChinese Academy of Fishery SciencesGuangzhouGuangdong510300 China School of Public Health Research Center of Public HealthRenmin Hospital of Wuhan UniversityWuhan UniversityWuhanHubei430071 China

5-Methylcytosine (5mC) is a dynamic and reversible epigenetic modification in genomic DNA of higher *** has been well-established that the demethylation of 5mC occurs through the ten-eleven translocation (TET)-mediated oxidation of 5mC followed by thymine DNA glycosylase (TDG)-initiated base excision repair (BER).Recent findings also have identified an alternative pathway of DNA *** this pathway,TET enzymes directly oxidize 5mC to form 5-formylcytosine (5fC) or 5-carboxylcytosine (5caC).These modified bases can undergo direct deformylation or decarboxylation,***,DNA demethylation can also occur through the deamination of 5mC and 5hmC,resulting in the production of thymine and 5-hydroxymethyluracil (5hmU),*** DNA demethylation pathways possess critical functional implications and roles in biological *** Recent Advances article will focus on the studies of mechanisms and biological functions of DNA demethylation,shedding light on the reversible nature of the epigenetic modification of 5mC.

关键词： Epigenetics DNA DNA methylation 5-Methylcytosine Demethylation Mechanisms biological functions C—C bond cleavage Mass spectrometry

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Energy budget of cold and hot gas-solid fluidized beds through CFD-DEM simulations

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Particuology 2024年第6期89卷 153-171页

作者： Lei bi Yunpeng Jiao Chunjiang Liu Jianhua Chen Wei Ge School of Chemical Engineering and Technology Tianjin UniversityTianjin 300072China State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of SciencesBeijing100190China School of Chemical Engineering University of Chinese Academy of SciencesBeijing 100049China

Direct energy budget is carried out for both cold and hot flow in gas–solid fluidization ***,the energy paths are proposed from thermodynamic *** consumption means total power input to the specific system,and it can be decomposed into energy retention and energy *** retention is the variation of accumulated mechanical energy in the system,and energy dissipation is the energy converted to heat by irreversible *** based on the Computational Fluid Dynamics-Discrete Element Method(CFD-DEM)framework,different energy terms are quantified from the specific flow elements of fluid cells and particles as well as their interactions with the *** order to clarify the energy budget,it is important to identify which system is studied:the particle-fluid system or the particle *** the cold flow,the total energy consumption of the particle sub-system can well indicate the onset of bubbling and turbulent,while the variation of local energy consumption terms can reflect the evolution of heterogeneous *** the hot flow,different heat transfer mechanisms are analyzed and the solver is modified to reproduce the experimental *** impact of the heat transfer mechanisms and heat production on energy consumption is also *** proposed budget method has proven to be energy-conservative and easy to conduct,and it is hopeful to be applied to other multiphase flow systems.

关键词： Energy budget Gas-solid fluidization CFD-DEM Regime transition Heat transfer mechanism

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Iron-nickel alloy particles with N-doped carbon “armor” as a highly selective and long-lasting catalyst for the synthesis of Nbenzylaniline molecules

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Nano Research 2024年第4期17卷 2308-2319页

作者： Gang Wang Longchao Sun Wanyi Liu Haijuan Zhan Shuxian bi College of Chemistry and Chemical Engineering Ningxia UniversityYinchuan 750021China

A scalable strategy for the convenient and rapid preparation of nitrogen-doped carbon-coated iron-based alloy catalysts was *** controlling the type and amount of metal salts in the precursor,various types of nitrogen-doped carbon-coated alloy catalysts can be prepared in a targeted ***_(2)Ni2@CN materials with small particle sizes and relatively homogeneous basic sites showed promising results in the N-alkylation reaction of benzyl alcohol with aniline(optimum yield:99%).It is worth noting that the catalyst can also be magnetically separated and recovered after the reaction,and its performance can be regenerated through simple ***,it was confirmed by kinetic experiments that the activation of C–H at the benzyl alcohol benzylic position is the rate-determining step(RDS).According to density flooding theory calculations,Fe_(2)Ni2@CN catalysts require less energy than other materials(Fe@CN and Ni@CN)for the RDS(dehydrogenation reaction)*** N-alkylation reactions are more easily carried out on Fe_(2)Ni2@CN catalysts,which may be the reason for the best catalytic activity of Fe-Ni alloy *** carbon-coated alloy materials will show great potential in more types of heterogeneous catalysis.

关键词： iron-nickel alloy catalyst N-alkylation reaction magnetic separation reaction path dehydrogenation reaction

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