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Effect of Waist Strap Reinforcement in Backpacks on Children Gait Parameters During Walking and Running: A Randomized Cross-Over Prospective Study 7

Effect of Waist Strap Reinforcement in Backpacks on Children...

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7th International Conference on material Strength and Applied Mechanics, MSAM 2024

作者： Huang, Li Xu, Yining Fekete, Gusztáv Gu, Yaodong Department of Material Science and Technology Audi Hungária Faculty of Vehicle Engineering Széchenyi István University Gyor9026 Hungary Faculty of Sports Science Ningbo University Ningbo315211 China

ISBN: (纸本)9781643685472

As academic demands increase, school-aged children and adolescents often carry heavy backpacks, impacting their posture and musculoskeletal health. This study examines how backpack carriage affects children's gait, focusing on the influence of waist strap design. In this study, twelve children underwent biomechanical tests while walking and running with and without backpacks, with weights adjusted based on daily habits. It can be found that waist strap-equipped backpacks significantly increased load response (F = 58.031, P © The Author(s), 2024.

关键词： Fatigue of materials

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Carrier Transfer From C-Plane to Semipolar-Plane Regions in a Red-Emitting InGaN/GaN Heterostructure

Carrier Transfer From C-Plane to Semipolar-Plane Regions in ...

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2024 Conference on Lasers and Electro-Optics, CLEO 2024

作者： Malhotra, Yakshita Shen, Yifan Wu, Yuanpeng Hanish, Josey Guo, Yifu Xiao, Yixin Sun, Kai Norris, Theodore Mi, Zetian Department of Electrical Engineering and Computer Science University of Michigan 1301 Beal Avenue Ann ArborMI48109 United States Department of Material Science and Engineering University of Michigan 2300 Hayward Street Ann ArborMI48109 United States

ISBN: (纸本)9781957171395

Temperature and power dependent time-resolved photoluminescence measurements are performed on a novel ultra-stable red-emitting InGaN/GaN heterostructure. PL dynamics at two distinct wavelengths indicate a lateral carrier transfer from c-plane to semipolar-plane InGaN in the structure. © Optica Publishing Group 2024 © 2024 The Author(s)

关键词： Photoluminescence

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Nanocellulose/nitrogen and fluorine co-doped graphene composite hydrogels for high-performance supercapacitors

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Nano Research 2023年第7期16卷 9519-9529页

作者： Yong Zhang Qingyun Zhou Wenhui Ma Chaohui Wang Xuefeng Wang Jiajun Chen Tiantian Yu Shan Fan College of Materials Science and Engineering Graphene Functional Materials Research LaboratoryQiqihar UniversityQiqihar 161006China College of Materials Science and Engineering Heilongjiang Province Key Laboratory of Polymeric Composition MaterialQiqihar UniversityQiqihar 161006China School of Chemistry and Chemical Engineering Qiqihar UniversityQiqihar 161006China Department of Practice Teaching and Equipment Management Qiqihar UniversityQiqihar 161006China

Three-dimensional graphene materials have been studied as typical supercapacitors electrode materials by virtue of their ultrahigh specific surface area and good ion transport ***,improvement of the poor volumetric electrochemical performance of these graphene materials has been required although they have high gravimetric energy *** this work,nanocellulose/nitrogen and fluorine co-doped graphene composite hydrogels(NC-NFGHs)were prepared through a convenient hydrothermal approach utilizing ammonium fluoride as the heteroatom ***(NC)and high concentration of graphene oxide(GO)were utilized to adjust the structure of NC-NFGHs and increase their packing ***,the aqueous symmetric supercapacitor based on NC-NFGH-80 exhibits remarkable gravimetric(286.6 F·g^(-1))and volumetric(421.3 F·cm^(-3))specific capacitance at 0.3 A·g^(-1),good rate performance,and remarkable cycle stability up to 10,000 ***,the all-solid-state flexible symmetric supercapacitors(ASSC)fabricated by NC-NFGH-80 also delivered a large specific capacitance of 117.1 F·g^(-1)at 0.3 A·g^(-1)and long service life over 10,000 cycles at 10 A·g^(-1).This compact porous structure and heteroatom co-doped graphene material supply a favorable strategy for high-performance supercapacitors.

关键词： compact graphene composite hydrogel high packing density N/F co-doping gravimetric/volumetric performances supercapacitors

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High Efficiency InGaN/GaN Nanowire LED Utilizing Exciton Recombination Dynamics

High Efficiency InGaN/GaN Nanowire LED Utilizing Exciton Rec...

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2024 Conference on Lasers and Electro-Optics, CLEO 2024

作者： Malhotra, Yakshita Pandey, Ayush Min, Jungwook Reddeppa, Maddaka Xiao, Yixin Li, Zidong Kan, Yuchen Guo, Yifu Wu, Yuanpeng Sun, Kai Deotare, Parag Mi, Zetian Department of Electrical Engineering and Computer Science University of Michigan 1301 Beal Avenue Ann ArborMI48109 United States Department of Material Science and Engineering University of Michigan 1301 Beal Avenue Ann ArborMI48109 United States

Facet formation in InGaN disc-in-wire LEDs leads to increased exciton binding energy due to strain relaxation and reduced polarization fields resulting in an ultra-high efficiency of 25.2% for green emission utilizing... 详细信息

ISBN: (纸本)9781957171395

关键词： Excitons

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Hot Deformation Behavior and Microstructures Evolution of GNP-Reinforced Fine-Grained Mg Composites

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Acta Metallurgica Sinica(English Letters) 2024年第3期37卷 407-424页

作者： Hengrui Hu Jiayu Qin Yunpeng Zhu Jinhui Wang Xiaoqiang Li Peipeng Jin Qinghai Provincial Key Laboratory of New Light Alloys Qinghai UniversityXining 810016China Qinghai Provincial Engineering Research Center of High Performance Light Metal Alloys and Forming Qinghai UniversityXining 810016China Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China School of Material Science and Engineering Lanzhou University of TechnologyLanzhou 730050China

Graphene nanoplates(GNPs)-reinforced magnesium matrix composites have been attracted great ***,knowledge is lack for the hot deformation behavior of GNP-reinforced magnesium(GNPs/Mg)*** this study,the fine-grained GNPs/Mg composite was fabricated by powder metallurgy process followed by *** hot deformation behavior,microstructure evolution and dynamic recrystallization(DRX)mechanism of fine-grained GNPs/Mg composite were investigated by hot compression test and electron back-scatter diffraction(EBSD).The hot compression tests of the composite were conducted at temperatures between 423 and 573 K with the strain rates from 0.001 to 1 s^(-1).The strain compensated power law equation was established to describe the hot deformation behavior of the *** stress exponent and activation energy of the composite are 7.76 and 83.23 kJ/mol,respectively,suggesting that the deformation mechanism is grain boundary slip controlled dislocation climb *** abnormally high stress exponent and activation energy are unattainable in the composite due to the fine grain size of the composites and the absence of Zener pinning and Orowan effects of GNPs *** grain size increases with the decrease in Zener-Hollomn(Z)parameter,which can be well fitted by power-law *** the increase in grain size and decrease in Z parameter,the geometrically necessary dislocation density decreases,which shows the approximately power-law relationship.A random and weak texture was formed after hot *** discontinuous dynamic recrystallization and continuous dynamic recrystallization mechanism dominated the DRX behavior at 473 K/0.001 s^(-1) and 573 K/0.001 s^(-1),respectively.

关键词： GNPs Mg composite Hot deformation behavior Constitutive equations Microstructure evolution Dynamic recrystallization

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Dual-metal atoms embedded into two-dimensional covalent organic framework as efficient electrocatalysts for oxygen evolution reaction:A DFT study

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Nano Research 2022年第9期15卷 7994-8000页

作者： Yanan Zhou Lanlan Chen Li Sheng Qiquan Luo Wenhua Zhang Jinlong Yang Hefei National Research Center for Physical Sciences at the Microscale University of Science and Technology of ChinaHefei 230026China Department of Material Science and Engineering University of Science and Technology of ChinaHefei 230026China Department of Chemical Physics University of Science and Technology of ChinaHefei 230026China Institutes of Physical Science and Information Technology Anhui UniversityHefei 230601China

The electrochemical oxygen evolution reaction(OER)is a half-reaction of water-splitting for hydrogen generation,yet suffers from its sluggish kinetics and large *** is highly desirable to develop efficient and stable OER electrocatalysts for the advancement of ***,by means of density functional theory(DFT)calculations,we systematically investigated a series of two-dimensional(2D)dual-atom catalysts(DACs)on a novel synthesized covalent organic framework(COF)material as potential efficient catalysts toward the *** designed 6 homonuclear(2TM-COF)and 15 heteronuclear(TM1TM2-COF)DACs all exhibit good *** is a strong scaling relationship between the adsorption Gibbs free energies of HO*and HOO*intermediates,and the OER overpotential(η^(OER))volcano curve can be plotted as a function ofΔGO*−ΔGHO*.RhIr-COF shows the best OER catalytic activity with aη^(OER)value of 0.29 V,followed by CoNi-COF(0.33 V),RuRh-COF(0.34 V),and NiIrCOF(0.37 V).These four OER DACs exhibit lower onset potential and higher current density than that of the IrO2(110)benchmark *** by the descriptor identification study,the Bader charge that correlated with the Pauling electronegativity of the embedded dual-metal atoms was found to be the most important factor governing the catalytic activity of the *** work highlights a potentially efficient class of 2D COF-based DACs toward the OER.

关键词： oxygen evolution reaction(OER) dual-atom catalysts(DACs) covalent organic framework(COF) density functional theory(DFT)

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Thermal History Effects on Decomposition Behavior and Pyrolysis Mechanism of Cellulose Nitrate 3

Thermal History Effects on Decomposition Behavior and Pyroly...

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3rd International Conference on Defence Technology, ICDT 2022

作者： Gao, Xu Jiang, Lin Xu, Qiang Das, Oisik School of Mechanical Engineering Nanjing University of Science and Technology Nanjing210094 China Material Science Division Department of Engineering Sciences and Mathematics Luleå University of Technology Luleå97187 Sweden

Nitrocellulose is an important kind of energetic material produced by replacing hydroxyl of cellulose molecule to nitro, which has a wide application range in social life. During transportation and storage, inevitably the quality of the nitrocellulose will be affected due to external ambient heating. In this study, two kinds of NC samples, original and heated ones, were used as research objects and taken into DSC experiments under several constant heating rates to explore thermal history effects on its decomposition and combustion behavior. A series of calculation methods based on model fitting were main ways for research, so were model free methods. Numerical results by model fitting method showed that decomposition reaction of NC follows n-th reaction model. The comparison between experimental results of two kinds of samples claimed that thermal history had positive influence on heat flow, and increased the reaction order of decomposition process, and decreased the characteristic temperatures. So the thermal history made the decomposition reaction more difficult to take place and more stable. This study is obviously meaningful for the research of thermal pyrolysis process of NC after thermal history. © Published under licence by IOP Publishing Ltd.

关键词： Nitrocellulose

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Optical and electrical conductivity properties of rare earth elements(Sm, Y, La, Er) co-doped CeO_(2)

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Journal of Rare Earths 2022年第10期40卷 1619-1627页

作者： Rabia Kιrkgecit Handan OzlüTorun Fatma Kιlc Dokan Esra Oztürk Institute of Science Material Science and EngineeringKahramanmaras Süt?üImam UniversityKahramanmaras46050Turkey Department of Energy System Engineering Kahramanmaras Istiklal UniversityKahramanmaras46300Turkey Department of Chemistry and Chemical Processing Technologies Kayseri UniversityKayseriTurkey Department of Metallurgical and Materials Engineering Karamanoglu Mehmetbey UniversityKaramanTurkey

In this research,un-doped CeO_(2) and Ce_(0.85)La_(0.10)MO_(0.05)O_(2)(M:Sm,Er,Y) compounds were synthesized by hydrothermal method and the multi-functional properties are *** defects were created with the additives of rare earth *** electrical and luminescence behaviors of the synthesized compounds were investigated in accord with the types of *** synthesized products were characterized by X-ray diffraction(XRD) analysis,Brunauer-Emmett-Teller(BET) measurement,UV-vis diffuse reflectance spectroscopy(DRS),scanning electron microscopy(SEM),photoluminescence(PL)spectroscopy and electrochemical impedance spectroscopic(EIS).All synthesized compounds are found to be nano-structured and have cubic *** total conductivity of all samples was ***,the total conductivity of un-doped CeO_(2),Ce_(0.85)La_(0.10)Y_(0.05)O_(2),Ce_(0.85)La_(0.10)Er_(0.05)O_(2) and Ce_(0.85)La_(0.10)Sm_(0.05)O_(2) is found to be 2.07×10^(-10),5.70×10^(-4),1.0×10^(-3) and 0.0747 S/cm,***,bandgap energy(E_(g)) of these samples calculated from UV visible absorption spectra is discussed,and the optical results show variation between 3.2 and 2.15 ***,the luminescence properties of the compounds were investigated and different emissions occur depending on the additive ***,photoluminescent emission spectra of Ce_(0.85)La_(0.10)Y_(0.05)O_(2),Ce_(0.85)La_(0.10)Er_(0.05)O_(2) and Ce_(0.85)La_(0.10)Sm_(0.05)O_(2) phosphors indicate that these phosphors have red,green and orange-red colors,respectively.

关键词： Cerium oxide Co-doping Conductivity Luminescence Oxygen vacancy Rare earth elements

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Effect of infill pattern on fatigue characteristics of 3D printed polymers

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materials Today: Proceedings 2023年 78卷 263-269页

作者： Dudescu, Mircea Cristian Racz, Laszlo Popa, Florin Department of Mechanical Engineering Technical University of Cluj-Napoca 103-105 Muncii Boulevard Cluj-Napoca 400641 Romania Department of Material Science and Engineering Technical University of Cluj-Napoca 103-105 Muncii Boulevard Cluj-Napoca 400641 Romania

The effect of the structure that is printed inside an object, known as infill pattern, on fatigue life of 3D printed specimens made of ABS was investigated in this paper. There are several infill pattern geometries, each with benefits and compromises between material usage, printing time or mechanical strength of the obtained part. Standard specimens with 100 % infill rate and rectilinear 0° and 90°, grid 0°–90° and ± 45°, triangular 60°, fast honeycomb, full honeycomb and wiggle infill patterns were tested. Following the completion of tensile tests to determine the ultimate tensile strength (UTS) of specimens, axial fatigue tests for each combination of infill pattern were conducted to measure the fatigue life for 90 %, 75 %, 60 %, 45 % and 40 % UTS. Comparative evaluation of the measured values revealed the strong influence of the printing patterns upon fatigue life. A simple mathematical model of the fatigue proprieties has been proposed for each infill patterns, statistical data shows that the proposed model ensures reasonably accurate prediction of fatigue life. The examination of fracture areas using electronic microscopy indicated the microstructural interaction between filaments underlying the main failure mechanisms, crazing, delamination and disbonding of the filaments and layers and their fracture. The results indicate that pattern with inclined filaments about tensile axis (grid±45°, rectilinear 0° and triangular 60°) have the maximum fatigue life compared with those with most of the filaments perpendicular to tensile direction (fast honeycomb, full honeycomb and rectilinear 90°). The pattern like grid 0°–90° and wiggle are very close to the first group, having filaments inclined (wiggle) or along and perpendicular to the tensile direction (grid 0°–90°). © 2022

关键词： Tensile strength

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Silk fibroin-based inks for in situ 3D printing using a double crosslinking process

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Bioactive materials 2024年第5期35卷 122-134页

作者： Francesca Agostinacchio Vincent Fitzpatrick Sandra Dire David LKaplan Antonella Motta National Interuniversity Consortium of Material Science and Technology FlorenceItaly BIOtech Research Center and European Institute of Excellence on Tissue Engineering and Regenerative Medicine Department of Industrial EngineeringUniversity of TrentoTrentoItaly Materials Chemistry Group&“Klaus Müller”Magnetic Resonance Laboratory Department of Industrial EngineeringUniversity of TrentoTrentoItaly Department of Biomedical Engineering Tufts UniversityMedfordMA02155USA

The shortage of tissues and organs for transplantation is an urgent clinical *** situ 3D printing is an advanced 3D printing technique aimed at printing the new tissue or organ directly in the *** ink for this process is central to the outcomes,and must meet specific requirements such as rapid gelation,shape integrity,stability over time,and adhesion to surrounding healthy *** natural materials,silk fibroin exhibits fascinating properties that have made it widely studied in tissue engineering and regenerative ***,further improvements in silk fibroin inks are needed to match the requirements for in situ 3D *** the present study,silk fibroin-based inks were developed for in situ applications by exploiting covalent crosslinking process consisting of a pre-photo-crosslinking prior to printing and in situ enzymatic *** different silk fibroin molecular weights were characterized and the synergistic effect of the covalent bonds with shear forces enhanced the shift in silk secondary structure towardβ-sheets,thus,rapid *** hydrogels exhibited good mechanical properties,stability over time,and resistance to enzymatic degradation over 14 days,with no significant changes over time in their secondary structure and swelling ***,adhesion to tissues in vitro was demonstrated.

关键词： Silk fibroin inks In situ 3D printing Covalent crosslinking Regenerative medicine Rapid gelation

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