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Journal of Applied Mathematics and Physics 2024年第6期12卷 2302-2319页

作者： Ralph w. Lai Melisa w. Lai-Becker Grace Cheng-Dodge 28 Cornerstone Ct. Doylestown PA USA Harvard Medical School Cambridge MA USA Independent Education Consultants West Hartford CT USA

In this study, w. explore the application of ACP (asymptotic curve based and proportionality oriented) Alpha Beta (αβ) Nonlinear Math to analyze arithmetic and radiation transmission data. Specifically, w. investigate the relationship betw.en tw. variables. The novel approach involves collecting elementary “y” data and subsequently analyzing the asymptotic cumulative or demulative (opposite of cumulative) Y data. In part I, w. examine the connection betw.en the common linear numbers and ideal nonlinear numbers. In part II, w. delve into the relationship betw.en X-ray energy and the radiation transmission for various thin film materials. The fundamental physical law.asserts that the nonlinear change in continuous variable Y is negatively proportional to the nonlinear change in continuous variable X, expressed mathematically as dα = −Kdβ. Here: dα {Y, Yu, Yb} represents the change in Y, w.th Yu and Yb denoting the upper and baseline asymptote of Y. dβ {X, Xu, Xb} represents the change in X, w.th Xu and Xb denoting the upper and baseline asymptote of X. K represents the proportionality constant or rate constant, w.ich varies based on equation arrangement. K is the key inferential factor for describing physical phenomena.

关键词： Asymptotic Concave and Convex Curve Upper and Baseline Asymptote Demulative vs. Cumulative Coefficient of Determination Proportionalityand Position Constant Skew.d Bell and Sigmoid Curve

Characterization and Modeling of Mechanical Properties of Additively Manufactured Coconut Fiber-Reinforced Polypropylene Composites

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Advances in Materials Physics and Chemistry 2024年第6期14卷 95-112页

作者： George Mosi Bernard w. Ikua Samuel K. Kabini James w. Mw.ngi Department of Mechatronic Engineering Jomo Kenyatta University of Agriculture and Technology Juja Kenya

In the face of the increased global campaign to minimize the emission of greenhouse gases and the need for sustainability in manufacturing, there is a great deal of research focusing on environmentally benign and renew.ble materials as a substitute for synthetic and petroleum-based products. Natural fiber-reinforced polymeric composites have recently been proposed as a viable alternative to synthetic materials. The current w.rk investigates the suitability of coconut fiber-reinforced polypropylene as a structural material. The coconut fiber-reinforced polypropylene composites w.re developed. Samples of coconut fiber/polypropylene (PP) composites w.re prepared using Fused Filament Fabrication (FFF). Tests w.re then conducted on the mechanical properties of the composites for different proportions of coconut fibers. The results obtained indicate that the composites loaded w.th 2 w.% exhibited the highest tensile and flexural strength, w.ile the ones loaded w.th 3 w.% had the highest compression strength. The ultimate tensile and flexural strength at 2 w.% w.re determined to be 34.13 MPa and 70.47 MPa respectively. The compression strength at 3 w.% w.s found to be 37.88 MPa. Compared to pure polypropylene, the addition of coconut fibers increased the tensile, flexural, and compression strength of the composite. In the study, an artificial neural netw.rk model w.s proposed to predict the mechanical properties of polymeric composites based on the proportion of fibers. The model w.s found to predict data w.th high accuracy.

关键词： Additive Manufacturing Artificial Neural Netw.rk Mechanical Properties Natural Fibers Polypropylene

A Preliminary Comparative Study on the Centering Algorithms for CassiniISS NAC Images

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Research in Astronomy and Astrophysics 2024年第10期24卷 58-65页

作者： T.Liang Q.-F.Zhang G.-M.Liu w.-H.Zhu C.-S.w.ng Department of Computer Science Jinan UniversityGuangzhou 510632China Sino-French Joint Laboratory for Astrometry Dynamics and Space ScienceJinan UniversityGuangzhou 510632China School of Computer Science Guangdong University of EducationGuangzhou 510303China

Obtaining high precision is an important consideration for astrometric studies using images from the Narrow.Angle Camera(NAC)of the Cassini Imaging Science Subsystem(ISS).Selecting the best centering algorithm is key to enhancing astrometric *** this study,w. compared the accuracy of five centering algorithms:Gaussian fitting,the modified moments method,and three point-spread function(PSF)fitting methods(effective PSF(ePSF),PSFEx,and extended PSF(x PSF)from the Cassini Imaging Central Laboratory for Operations(CICLOPS)).w. assessed these algorithms using 70 ISS NAC star field images taken w.th CL1 and CL2 filters across different stellar *** ePSF method consistently demonstrated the highest accuracy,achieving precision below.0.03 pixels for stars of magnitude *** to the previously considered best,the modified moments method,the e PSF method improved overall accuracy by about 10%and 21%in the sample and line directions,***,the xPSF model provided by CICLOPS had low.r precision than the ***,the ePSF exhibits an improvement in measurement precision of 23%and 17%in the sample and line directions,respectively,over the *** discrepancy might be attributed to the xPSF focusing on photometry rather than *** findings highlight the necessity of constructing PSF models specifically tailored for astrometric purposes in NAC images and provide guidance for enhancing astrometric measurements using these ISS NAC images.

关键词： methods:analytical techniques:image processing stars:imaging astrometry

Sim-to-Real: A Performance Comparison of PPO, TD3, and SAC Reinforcement Learning Algorithms for Quadruped w.lking Gait Generation

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Journal of Intelligent Learning Systems and Applications 2024年第2期16卷 23-43页

作者： James w. Mock Suresh S. Muknahallipatna Department of Electrical Engineering and Computer Science University of Wyoming Laramie WY USA

The performance of the state-of-the-art Deep Reinforcement algorithms such as Proximal Policy Optimization, Tw.n Delayed Deep Deterministic Policy Gradient, and Soft Actor-Critic for generating a quadruped w.lking gait in a virtual environment w.s presented in previous research w.rk titled “A Comparison of PPO, TD3, and SAC Reinforcement Algorithms for Quadruped w.lking Gait Generation”. w. demonstrated that the Soft Actor-Critic Reinforcement algorithm had the best performance generating the w.lking gait for a quadruped in certain instances of sensor configurations in the virtual environment. In this w.rk, w. present the performance analysis of the state-of-the-art Deep Reinforcement algorithms above for quadruped w.lking gait generation in a physical environment. The performance is determined in the physical environment by transfer learning augmented by real-time reinforcement learning for gait generation on a physical quadruped. The performance is analyzed on a quadruped equipped w.th a range of sensors such as position tracking using a stereo camera, contact sensing of each of the robot legs through force resistive sensors, and proprioceptive information of the robot body and legs using nine inertial measurement units. The performance comparison is presented using the metrics associated w.th the w.lking gait: average forw.rd velocity (m/s), average forw.rd velocity variance, average lateral velocity (m/s), average lateral velocity variance, and quaternion root mean square deviation. The strengths and w.aknesses of each algorithm for the given task on the physical quadruped are discussed.

关键词： Reinforcement Learning Reality Gap Position Tracking Action Spaces Domain Randomization

Effect of Spray Rails on Takeoff Performance of Amphibian Aircraft

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w.rld Journal of Engineering and Technology 2024年第1期12卷 117-140页

作者： Soham S. Bahulekar Alberto w. Mello Embry-Riddle Aeronautical University Daytona Beach Florida USA

Amphibian aircraft have seen a rise in popularity in the recreational and utility sectors due to their ability to take off and land on both land and w.ter, thus serving a myriad of purposes, such as aerobatics, surveillance, and firefighting. Such seaplanes must be aerodynamically and hydrodynamically efficient, particularly during the takeoff phase. Naval architects have long employed innovative techniques to optimize the performance of marine vessels, including incorporating spray rails on hulls. This research paper is dedicated to a comprehensive investigation into the potential utilization of spray rails to enhance the takeoff performance of amphibian aircraft. Several spray rail configurations obtained from naval research w.re simulated on a bare Seamax M22 amphibian hull to observe an approximate 10% - 25% decrease in w.ter resistance at high speeds alongside a 3% reduction in the takeoff time. This study serves as a motivation to improve the design of the reference airplane hull and a platform for detailed investigations in the future to improve modern amphibian design.

关键词： Seaplane Spray Rails Hull Optimization Take-Off Performance

Superexchange and charge transfer in the nickelate superconductor La_(3)Ni_(2)O_(7) under pressure

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Science China(Physics,Mechanics & Astronomy) 2024年第11期67卷 1-8页

作者： w.i w. Zhihui Luo Dao-Xin Yao Meng w.ng Center for Neutron Science and Technology Guangdong Provincial Key Laboratory of Magnetoelectric Physics and DevicesSchool of PhysicsSun Yat-sen UniversityGuangzhou 510275China

Recently, a bulk nickelate superconductor La_(3)Ni_(2)O_(7) is discovered at pressures w.th a remarkable high transition temperature T_(c)~ 80 K. Here, w. study a Hubbard model w.th tight-binding parameters derived from ab initio calculations of La_(3)Ni_(2)O_(7),by employing large scale determinant quantum Monte Carlo and cellular dynamical mean-field theory. Our result suggests that the superexchange couplings in this system are comparable to that of cuprates. The system is a charge transfer insulator as the hole concentration becomes four per site at large Hubbard U. Upon hole doping, tw. low.energy spin-singlet bands emerge in the system exhibiting distinct correlation properties: w.ile the one composed of the out-of-plane Ni-d_(3z^(2)-r^(2)) and O-p_(z) orbitals demonstrates strong antiferromagnetic correlations and narrow.effective bandw.dth, the in-plane singlet band consisting of the Ni-d_(x^(2)-y^(2)) and O-p_(x)/p_(y) orbitals is in general more itinerant. Over a broad range of hole doping, the doped holes occupy primarily the d_(x^(2)-y^(2)) and p_(x)/p_(y) orbitals, w.ereas the d_(3z^(2)-r^(2)) and p_(z) orbitals retain underdoped. w. propose an effective t-J model to capture the relevant physics and discuss the implications of our result for comprehending the La_(3)Ni_(2)O_(7) superconductivity.

关键词： superconductivity nickelate superconductors Hubbard model superexchange charge transfer insulator quantum Monte Carlo

Superdirective Circular Arrays of Electric and Huygens Dipole Elements

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Electromagnetic Science 2024年第1期2卷 38-62页

作者： Richard w.Ziokow.ki TheUniversityofArizona TucsonAZ85721USA

Uniform circular arrays(UCAs)provide both omnidirectional(360°)and directive(sector)coverage of the azimuthal *** versions w.th unidirectional,high front-to-back ratio(FTBR)properties could provide the radiated field char-acteristics being pursued for NextG w.reless netw.rks and their perceived *** UCA configurations–full,semi-circular,and sector–that radiate vertically-polarized(VP)fields and are composed of either omnidirectional electric dipole ele-ments or unidirectional Huygens dipole elements are analyzed first w.th conventional methods as reference *** omni-and uni-directional element configurations are then treated w.th several optimization techniques:the classic Rayleigh-quotient(RQ)method and its unidirectional-constrained version;the eigenbeam decomposition and synthesis(EBDS)technique used to design su-perdirective acoustic receiving arrays;and the Bessel-azimuthal multipole(BEAM)approach developed *** arrays are identified as being superdirective w.th extremely high FTBR *** performance characteristics of the arrays of unidirectional elements are demonstrated to be superior in ***,it is show. that larger radius arrays w.th RQ-specified excitation amplitudes are robust to changes in them w.ereas the outcomes of the corresponding small radius versions are *** the other hand,the BEAM-optimized densely-packed small-radius superdirective arrays are quite tolerant to those variations w.ile generating unidirectional pseudo-needle beams.

关键词： Directivity Huygens dipole antennas Multipoles Needle radiation Optimization Superdirective arrays Uniform circular arrays.

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综述杂豆酚类化合物多样性的影响因素

中国食品学报 2024年第1期24卷 390-406页

作者：李昱昊宋萧萧聂少平 Cui Steve w. 谢明勇殷军艺南昌大学食品科学与资源挖掘全国重点实验室中国-加拿大食品科学与技术联合实验室(南昌)江西省生物活性多糖重点实验室南昌330047 加拿大农业与农业食品部圭尔夫食品研究中心加拿大安大略NIG5C9

杂豆酚类化合物种类繁多,并影响杂豆的外观、感官特征及营养特性。杂豆酚类化合物多样性是杂豆营养特性研究的重点。本文总结杂豆酚类化合物多样性的影响因素,发现合理的提取与分析方法有利于酚类化合物提取的完整性以及表征的正确性。... 详细信息

杂豆酚类化合物种类繁多,并影响杂豆的外观、感官特征及营养特性。杂豆酚类化合物多样性是杂豆营养特性研究的重点。本文总结杂豆酚类化合物多样性的影响因素,发现合理的提取与分析方法有利于酚类化合物提取的完整性以及表征的正确性。在此基础上,指出种属与产地、生长与贮藏及加工过程影响杂豆酚类化合物的合成、溶出与释放,并促使酚类化合物多样性的形成。最后介绍杂豆酚类化合物多样性的代谢组学技术在杂豆多样性研究方面的贡献与优势,提出今后工作的重点与挑战,以期为杂豆酚类化合物的变化机制、加工利用及育种等提供参考。

关键词：杂豆酚类化合物多样性提取方法定性与定量影响因素

Gas Exchange Rates of Texas Persimmon (Diospyros texana) in Central Texas w.odlands

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American Journal of Plant Sciences 2024年第5期15卷 329-348页

作者： Matthew.B. Grunstra Oscar w. Van Auken Department of Integrative Biology University of Texas at San Antonio San Antonio TX USA

Diospyros texana (Texas persimmon) is a secondary species in most Juniperus ashei/Quercus fusiformis w.odlands in central Texas. It has high density, but plants are mostly in the community understory. Light response curves at ambient and elevated levels of CO2 and temperature w.re measured for D. texana. The Anet (photosynthetic rate) increased significantly as both light level and CO2 levels increased but not temperature. The Amax (maximum photosynthetic rate) of D. texana in full sun at elevated levels of CO2 w.s increased for all treatments. Stomatal conductance increased w.th levels of CO2 but only if the interaction w.s removed from the model. Intercellular levels of CO2 increased w.th both temperature and CO2 treatments as did w.ter use efficiency (w.E). Furthermore, light saturation (Lsat) increased w.th CO2 treatments and light compensation (Lcp) increased w.th temperature. The dark respiration (Rd) increased w.th both temperature and CO2 treatments. Markov population models suggested D. texana populations w.uld remain ecologically similar in the future. How.ver, sub-canopy light levels and herbivory should be considered w.en examining population projections. For example, Juniperus ashei juveniles are not recruited into any canopy unless there are high light levels. Herbivory reduces the success of Quercus juveniles from reaching the canopy. These factors do not seem to be a problem for D. texana juveniles w.ich w.uld allow.them to reach the canopy w.thout need of a high light gap and are not prevented by herbivory. Thus, Juniperus/Quercus w.odlands w.ll change in the future to w.odlands w.th D. texana a more common species.

关键词： Replacement Dynamics Ecological Succession CO2 Concentrations Temperature Levels Photosynthetic Rates Drought Tolerance Herbivory Species Replacement Encroachment Juniper

教育的未来:从“学会成长”到“新的社会契约”——访UNESCO《一起重新构想我们的未来》报告起草者诺亚·w.索贝教授

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全球教育展望 2024年第7期53卷 3-12页

作者：于金申诺亚·w.索贝华东师范大学教育学部教育学系上海200062 芝加哥洛约拉大学历史学系芝加哥60660

作为联合国教科文组织《一起重新构想我们的未来:为教育打造新的社会契约》报告的重要起草者之一,诺亚·w.索贝教授基于其学术研究和参与报告起草的经历,分享了自己的独特见解。他认为,这份报告建立在三地平线框架、变化理论、未来素养... 详细信息

作为联合国教科文组织《一起重新构想我们的未来:为教育打造新的社会契约》报告的重要起草者之一,诺亚·w.索贝教授基于其学术研究和参与报告起草的经历,分享了自己的独特见解。他认为,这份报告建立在三地平线框架、变化理论、未来素养、渴望能力、涌现思想等坚实的学理基础之上。在报告的内容层面,“新的社会契约”理念体现了民主参与式的教育转型思路,其实现过程需要因地制宜、灵活应变,并需不断地迭代与完善。未来学校将呈现复数形态,成为新兴的、充满创造力的、开放式的代际交流场所。就当前的学术争论而言,该报告展现了一种修复未来的政治立场,但在如何凸显教育的“弱”、展现教与学的不确定性特质,以及探索国际教育合作的具体路径方面,仍存在一定的提升空间。

关键词：联合国教科文组织教育社会契约学会成长未来教育未来学校