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Morphology-controlled porphyrin nanocrystals with enhanced photocatalytic hydrogen production

Nano Research 2022年第6期15卷 5719-5725页

作者： Ronghui Cao Jinghan Wang Yusen Li Jiajie Sun Feng Bai School of Physics and Electronics Henan UniversityKaifeng 475004China Key Laboratory for Special Functional Materials of Ministry of Education National and Local Joint Engineering Research Center for High-efficiency Display and Lighting TechnologySchool of Materials Science and Engineeringand Collaborative Innovation Center of Nano Functional Materials and ApplicationsHenan UniversityKaifeng 475004China Academy for Advanced Interdisciplinary Studies Henan UniversityKaifeng 475004China

Molecular self-assembly is a natured-inspired strategy to integrate individual functional molecules into supramolecular nanostructured materials through noncovalent bond interactions for solar to fuel ***,the design and engineering of the morphology,size,and orderly stacking of supramolecular nanostructures remain a great *** this study,regular porphyrin nanocrystals with different orderly stacked structures are synthesized through noncovalent self-assembly of Pt(II)meso-tetra(4-carboxyphenyl)porphine(PtTCPP),using surfactants with different *** synergy of noncovalent bond interactions between porphyrin molecules,and between porphyrin molecules and surfactants resulted in different molecular packing *** to the spatial ordering of PtTCPP molecules,the different nanocrystals exhibit both collective optical properties and morphology-dependent activities in photocatalytic hydrogen *** measurements of the photodeposition of dual cocatalysts showed that the photogenerated electrons and holes selectively aggregated at different active sites,revealing separation pathways and directional transfer of photogenerated electrons and holes in the *** study provides a new strategy to exert rational control over porphyrin self-assembly nanocrystals for highly efficient water splitting.

关键词： porphyrin self-assembly morphology-dependent photocatalytic activity directional transfer photogenerated electrons and holes

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A Soft-Robotic Thumb Orthosis Facilitating Individual Assistance of Thumb Joints

A Soft-Robotic Thumb Orthosis Facilitating Individual Assist...

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IEEE International Conference on Soft Robotics (RoboSoft)

作者： Christina Chase-Markopoulou Anoush Sepehri Tania K. Morimoto Michael T. Tolley Department of Mechanical and Aerospace Engineering Department of Surgery Materials Science and Engineering Program University of California San Diego CA USA

ISBN: (数字)9798331520205

ISBN: (纸本)9798331520212

Many wearable soft robotic devices have been developed to assist with spasticity – the increased muscle tone seen in individuals with neurological conditions such as stroke or cerebral palsy. However, these devices typically lack the ability to individually assist multiple degrees of freedom (DOF), which is essential to performing a broad range of daily tasks. To address this need, we developed a soft robotic thumb orthosis to achieve movement in three DOF. We focused on the thumb as it performs the most complex movement. Our orthosis used three unfolding textile pneumatic actuators to assist with the extension of the interphalangeal joint, combined extension of the metacarpal and carpometacarpal joints, and abduction of the carpometacarpal joint. The orthosis was tested on both a 3D-printed biomimetic test bed that emulated spasticity and a healthy individual. The orthosis met the full range of motion targets for each joint, except for the abduction of the carpometacarpal joint with medium spasticity, and surpassed the range of motion threshold required for activities of daily living. The orthosis was able to: (1) assist each DOF independently, (2) move the tip of a biomimetic thumb to a pre-determined target with total error of less than 1.5 cm when actuated with open-loop control, and, (3) provide individual joint assistance to a user with no motor impairment. This research showcases the ability of a soft robotic orthosis to assist movement in simulated spasticity of individual thumb joints and provides an important step towards a platform to study whether independent joint assistance during rehabilitation improves patient outcomes.

关键词： Performance evaluation Pneumatic actuators Biomimetics Thumb Spasticity Soft robotics Muscles Motors Motion control Textiles

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Computational Modeling of Radiation Effects in Carbon Fiber-Reinforced Polyethylene Composites 38

Computational Modeling of Radiation Effects in Carbon Fiber-...

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38th Technical Conference of the American Society for Composites, ASC 2023

作者： Li, Fuyue Woodrough, Mary Deo, Chaitanya School of Materials Science and Engineering Georgia Institute of Technology North Avenue AtlantaGA30332 United States Nuclear and Radiological Engineering Program GWW School of Mechanical Engineering Georgia Institute of Technology North Avenue AtlantaGA30332 United States

ISBN: (纸本)9781605956916

Radiation effect in carbon fiber-filled polyethylene composites are of importance in space and aircraft applications. A two-fold approach is employed to study radiation effects in carbon nanotube polyethylene as the exemplar. First, a radiation transport model is created with a single-wall carbon nanotube (SWCNT) as thin carbon slab superimposed on a slab of medium-density polyethylene matrix. Different weight fractions of SWCNT are examined and compared with an integrated model for the shielding abilities of galactic cosmic radiation. Second, molecular dynamics simulation with bond-order force field are conducted for 350 eV carbon recoil cascade simulation. Preliminary results discuss the effect of SWCNT on the radiation damage of crystalline polyethylene. Transport simulation demonstrate the efficacy of the slab model in predicting the shielding abilities and concluded that the dose increases with increasing SWCNT filler. Molecular dynamics simulations demonstrate that adding SWCNT enhances the radiation resistance with fewer free molecules produced. © 2023 by DEStech Publications, Inc. and American Society for Composites. All rights reserved.

关键词： Single-walled carbon nanotubes (SWCN)

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Chemically inducing room temperature spin-crossover in double layered magnetic refrigerants Pr1.4+xSr1.6-xMn2O7(0.0≤x≤0.5)

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Journal of materials science & Technology 2022年第29期124卷 232-242页

作者： Akshay Kumar Kavita Kumari Mohit K.Sharma Ankush Vij Shalendra Kumar Seok-Hwan Huh Bon Heun Koo Department of Materials Convergence and System Engineering Changwon National UniversityChangwonGyeongnam51140South Korea School of Material Science and Engineering Changwon National UniversityChangwonGyeongnam51140South Korea Department of Physics University of Petroleum&Energy StudiesDehradun248007India Department of Physics College of ScienceKing Faisal UniversityHofufAl-Ahsa31982Saudi Arabia

The height of total entropy(S)for a magnetic refrigerant material is essentially concerned with the magnetic and structural ***,the participation of such transitions in layered materials is not well ***,the purpose of this work is to investigate the interplay between double layer lattice with their single perovskite counterpart,to achieve optimal magnetocaloric performance.A series of self-doped Pr_(1.4+x)Sr_(1.6-x)Mn_(2)O_(7)(0.0≤x≤0.5)Ruddlesden-Popper(R-P)perovskite have been prepared through the solid-state sintering *** increasing the Pr-stoichiometry,the lattice faults have increased and the double layer lattice dramatically disintegrates into single perovskite *** to the reduction of bilayer R-P phase into single perovskite the spin crossover occurs from weak bilayer(T=304 K)interactions towards the strong three-dimensional(T=308 K)interactions *** series consistently develops thermomagnetic irreversibility in zero-field cooled(ZFC)-field cooled(FC)magnetization,which is indicative of a spin-glass *** glassy nature has been ascribed collectively to the lattice strain produced because of dislocations and to an antiferromagnetic phase segregated at the *** maximum value of temperature average entropy change(TEC)and adiabatic temperature(ΔT)has enhanced nearly by 4 folds from 0.53 J kg^(-1)K^(-1),0.59 K(for x=0.0)up to 1.85 J kg^(-1)K^(-1),10 K(for x=0.5)at 2.5 T,***,the room temperature relative cooling power has improved from 26.94 J/kg up to 77.84 J/kg with an applied field of 2.5 *** findings in this work suggest that the controlled reduction of double layer lattice into single perovskite and/or existence of both phases simultaneously in bilayer R-P manganites may be very effective in obtaining the desirable characteristics of magnetocaloric effects.

关键词： Magnetic refrigerant Bilayer manganites Magnetocaloric effect Ruddlesden-popper perovskite Relative cooling power

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Ultra-transparent nanostructured coatings via flow-induced one-step coassembly

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Nano materials science 2022年第2期4卷 97-103页

作者： Jingjing Liu Sonia E.Chavez Hao Ding Maria M.Farooqui Zaili Hou Sharon Lin Thomas D.D'Auria Julia M.Kennedy Anna Marie LaChance Luyi Sun Polymer Program Institute of Materials ScienceUniversity of ConnecticutStorrsConnecticut06269United States Department of Chemical&Biomolecular Engineering University of ConnecticutStorrsConnecticut06269United States Department of Biomedical Engineering University of ConnecticutStorrsConnecticut06269United States

Polyvinyl alcohol(PVA)/laponite(LP)nanocomposite coatings were fabricated via a facile one-step coassembly *** formed nanocoatings contain a high concentration of LP nanosheets,which can be well aligned along the substrate surface during the coassembly *** to the highly orientated structure,the flexible nanocoatings exhibit ultra-high transparency and superior mechanical properties,and can also act as excellent gas *** nanocoatings can be exceptional candidates for a variety of applications,such as food packaging.

关键词： Nanocoating Coassembly Polyvinyl alcohol Laponite

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Formation of the structure-Ⅱgas hydrate from low-concentration propane mixed with methane

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Chinese Journal of Chemical engineering 2023年第6期58卷 306-314页

作者： Sanya Du Xiaomin Han Wenjiu Cai Jinlong Zhu Xiaobai Ma Songbai Han Dongfeng Chen Yusheng Zhao Hui Li Hailong Lu Xiaohui Yu Beijing Advanced Innovation Center for Soft Matter Science and Engineering Beijing University of Chemical TechnologyBeijing 100029China National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China College of Engineering Peking UniversityBeijing 100871China Beijing International Center for Gas Hydrate School of Earth and Space SciencesPeking UniversityBeijing 100871China Department of Physics Southern University of Science and Technology(SUSTech)Shenzhen 518055China Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou) Guangzhou 511458China Department of Nuclear Physics China Institute of Atomic EnergyBeijing 102413China Academy for Advanced Interdisciplinary Studies Southern University of Science and Technology(SUSTech)Shenzhen 518055China Songshan Lake Materials Laboratory Dongguan 523808China

It has been recognized that a small amount of propane mixed with methane can change greatly in not only the thermodynamics but also the structural properties of gas ***,its mechanism is still not well understood *** this research,structure-Ⅱ(sⅡ)hydrate is synthesized using a methanepropane gas mixture with an initial mole ratio of 99:1,and it is found that large(5~(12)6~4)cages are cooccupied by multiple gases based on the rigid structure analysis of neutron diffraction *** first principles calculation and molecular dynamics simulation are conducted to uncover the molecular mechanism for sⅡmethane-propane hydrate formation,revealing that the presence of propane inhibits the formation of structure-Ⅰ(sⅠ)hydrate but promotes sⅡhydrate *** results help to understand the accumulation mechanism of natural gas hydrate and benefit to optimize the condition for gas storage and transportation in hydrate form.

关键词： Multiple guest molecules Clathrates Neutron powder diffraction Structural transformation Molecular mechanism

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Dry-season sources of riverine sediment from the tropical mixed urban-agricultural watershed of the Mun River Basin in northeastern Thailand

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International Journal of Sediment Research 2023年第2期38卷 240-252页

作者： Arika Bridhikitti Thayukorn Prabamroong Gaohuan Liu Environmental Engineering and Disaster Management Program School of Interdisciplinary Studies Mahidol University Kanchanaburi Campus Earth Science Research Center Mahidol University Kanchanaburi Campus Faculty of Environment and Resource Studies Mahasarakham University State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences

Northeastern(NE) Thailand is well recognized as the land for rice cropping and consequently, it is potentially contaminated with chemicals from soil fertilization, pest/weed control, and urban *** Mun River basin in NE Thailand principally is comprised of rice paddies and sedimentation in the river has been pronounced, but the studies on sediment source identification are limited. The current study aims to identify sediment sources in the Mun River basin and discuss possible impacts on ecosystems attributed to exposure to polluted sediment. The assessment relies upon physicochemical properties and heavy metal contents(iron(Fe), manganese(Mn), copper(Cu), chromium(Cr), nickel(Ni),and Zinc(Zn)) in the fine-grained sediment(<63 μm) taken from the Mun River basin and the Chi River in the dry season of 2020-2021. The findings revealed that the heavy metals in the sediment had not accumulated to levels of concern. Most sediment was from natural sources, including Fe-and Mn-rich sediment, Cr-dominant sediment, and Ni-and Cu-rich sediment. Fe-and Zn-rich sediment was, however, found in the urban watershed of Lam Ta Klong, and it could originate from mixed urban sources. Ferich sediment was predominant in the Mun River basin, which and could be a significant sink and source of toxic elements from agricultural and urban discharges. It is suggested that the toxic compounds in the sediment should be consistently monitored, whereas ecological and health risk assessment should be focused on the mobile forms.

关键词： Sediment Heavy metals Mun River Lower Mekong River Agriculture

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Enhanced resistive switching properties of HfAlOx/ZrO2- based RRAM devices

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Progress in Natural science:materials International 2022年第5期32卷 602-607页

作者： P.R.Sekhar Reddy Venkata Raveendra Nallagatla Yedluri Anil Kumar G.Murali School of Material Science and Engineering Pusan National University Department of Physics and Oxide Research Centre Memory and Catalyst Research Center Hankuk University of Foreign Studies Materials Center Leoben Forschung GmbH Department of Physics United Arab Emirates University Department of Polymer Science and Engineering Department of IT-Energy Convergence (BK21 FOUR) Chemical Industry Institute Korea National University of Transportation

Resistive Random-Access Memory（RRAM） devices are recognized as potential candidates for next-generation memory devices, due to their smallest cell size, high write/erase speed, and endurance. Particularly, the resistive switching（RS） characteristics in oxide materials have offered new opportunities for developing CMOScompatible high-density RRAM devices. In this study, the RS behavior of HfAlOx/ZrO2thin films sandwiched structure between TiN bottom electrode and Au top electrodes were investigated. It was found that Au/HfAlOx/ZrO2/TiN stacks were superior in terms of RS performance when compare to Au/HfAlOx/TiN memory stacks. The devices demonstrated a good resistance ratio of high resistance state and low resistance state ～103 for Au/HfAlOx/TiN and ～105 for Au/HfAlOx/ZrO2/TiN stacks, respectively. Both stacks showed good retention characteristics（>104s） and endurance（>103cycles）. The experimental current-voltage characteristics fitted with different conducting mechanisms, the linear lower bias region is dominated by ohmic conductivity, whereas the non-linear higher bias region was dominated by space-charge limited current conduction mechanism.

关键词： Nonvolatile memory RRAM Resistive switching mechanism Atomic layer deposition Current conduction mechanism

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The behavior of different clays subjected to a fast-drying cycle for traditional ceramic manufacturing

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Journal of King Saud University - engineering sciences 2024年第5期36卷 339-348页

作者： Zaccaron, Alexandre de Souza Nandi, Vitor Dal Bó, Marcelo Arcaro, Sabrina Bernardin, Adriano Michael Program on Materials Science and Engineering Universidade do Extremo Sul Catarinense Avenida Universitária 1105 Santa Catarina Criciúma88806-000 Brazil SC Criciúma88813-600 Brazil Ceramic Materials Group Parque Científico e Tecnológico Rodovia Jorge Lacerda 3800 Santa Catarina Criciúma88807-400 Brazil

studies have been widely carried out on drying techniques and equipment. The behavior of clays subjected to drying stages requires further research. This study aims to evaluate the behavior of the clay ceramic body during the different stages of the drying cycle and match the characteristics of the raw materials with the final quality of the pieces. In this work, the behavior of three different clays in terms of drying performance was studied. The clays were selected, and their chemical, mineralogical, and particle size characteristics were measured. The mixture design (DoE) developed 10 formulations and was processed through vacuum extrusion. The samples were subjected to forced drying cycles of 180 min by varying the temperature from 30 to 90 °C and air speed from 1.5 to 4.0 m/s. At the end of the cycle, the retraction was a determining factor for the crack probability indicator, where formulations that obtained ∼10% retraction in the dry zone showed losses >25%. On the other hand, it is could be stated that claystone assists the drying process of the ceramic piece, minimizing losses. The drying sensitivity coefficient (k-factor) presented values that reproduce the number of losses during drying, proving to be a valid tool to relate clay properties, drying conditions, and losses in this process. In this case, drying process losses >25% were observed when the k-factor was from 1.6. © 2022 The Authors

关键词： Drying

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Injectable Platelet-Rich Fibrin in Contact with Bone Substitutes, Porous Zirconia, or Laser-Textured Implant Surfaces: A Detailed Morphological Analysis

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Biomedical materials and Devices 2024年第1期2卷 415-426页

作者： Oliveira, Miguel Noronha Varela, Hugo Almeida Nascimento, Rubens M. Sahoo, Narayan Carvalho, Oscar Henriques, Bruno Souza, Júlio C. M. Ceramic and Composite Materials Research Group (CERMAT) Department of Mechanical Engineering (EMC) Federal University of Santa Catarina (UFSC) Post-graduate Program in Materials Science and Engineering Federal University of Rio Grande Norte (UFRN) Center for MicroElectroMechanical Systems (CMEMS-UMINHO) Universidade do Minho LABBELS - Associate Laboratory University of Minho University Institute of Health Sciences (IUCS) CESPU

The aim of the present study was to perform a detailed morphological analysis of an injectable platelet rich fibrin after combination with two different particulate hydroxyapatite-based granules, a porous zirconia block, and laser-textured zirconia or titanium surfaces. Blood samples were harvested from three participants to prepare the flowable injectable PRF in contact or not with particulate hydroxyapatite (Hap), bone mineral granules (DBBM), porous zirconia blocks, laser-textured titanium or zirconia surfaces. Optical and scanning electron microscopy (SEM) were used to evaluate the fibrin network density, fibrin fibers’ diameter, blood cells, and the interaction of PRF with the biomaterials. Histomorphometry of the flowable PRF was also performed using the hematoxylin–eosin staining protocol. Specimens were independently evaluated by two blinded and well-trained researchers in histomorphometry and microscopy. Particulate Hap and DBBM shown different morphological aspects by SEM analyses since DBBM revealed macro- and micro-scale pores while Hap revealed a dense structure. Hydroxyapatite and DBBM granules were entirely embedded by the fibrin-network in the presence of leukocytes and blood platelets. The zirconia porous structured was filled with PRF and its components. Also, the laser-structured zirconia or implant surfaces were entirely coated with the PRF fibrin network embedding leukocytes and blood platelets. Laser-textured titanium surfaces revealed macro- and micro-scale irregularities that increase the surface area and retention of the injectable PRF. Histomorphometric analyses revealed complementary details on the distribution of lymphocytes, red blood cells, and fibrin associated with platelet aggregation. The flowing and viscosity of an injectable platelet rich fibrin provided an agglomeration of synthetic or xenogeneic particulate bone substitutes and the coating of porous zirconia and textured implant surfaces as inspected by scanning electron microsc

关键词： Bone healing Bone substitutes Histology Morphology Platelet-rich fibrin

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