1,007 research outputs found

    Międzynarodowy Ranking Uniwersytetów (Academic Ranking of World Universities)- metodologia i problemy

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    The Institute of Higher Education at Shanghai Jiao Tong University has published the Academic Ranking of World Universities on the Internet. The ranking has drawn wide attention worldwide. Within the ranking institutions are ranked according to their academic or research performance. Ranking indicators include the alumni and staff winning major International awards, highly cited researchers in major research fields, articles published in selected top journals and articles indexed by major citation indexes, as well as performance per capita. Methodological problems discussed in the article include quantitative versus qualitative evaluation, evaluation of research versus education, variety of institutions, language of publications, selection of awards and studying and working experience of award winners. The article also discusses technical problems such as definition of institutions, name expression of institutions, merging and splitting of institutions, searching and attribution of publications.Instytut Szkolnictwa Wyższego (Institute of Higher Education), działający w ramach Shanghai Jiao Tong University, opublikował w Internecie międzynarodowy ranking uniwersytetów (Academic Ranking of World Universities), który odbił się szerokim echem na całym świecie. W rankingu tym szkoły wyższe szereguje się według wyników działalności dydaktycznej i badawczej. Wśród wskaźników stosowanych w rankingu znajdują się m.in. liczba absolwentów oraz pracowników zdobywających prestiżowe nagrody międzynarodowe, często cytowanych badaczy w ważniejszych dziedzinach badań, liczba artykułów publikowanych w wybranych, przodujących czasopismach oraz artykułów uwzględnianych w najważniejszych indeksach cytowań, a także efektywność działania ujęta w przeliczeniu na jedną osobę {performance per capita). Problemy metodologiczne omawiane w niniejszym artykule to m.in. ocena ilościowa i jakościowa, ocena działalności badawczej uczelni oraz oferowanego przez nie kształcenia, różnorodność instytucji szkolnictwa wyższego, język publikacji, kryteria wyboru nagród oraz doświadczenia edukacyjne i zawodowe osób uhonorowanych nagrodami. W artykule omówiono także zagadnienia natury technicznej, takie jak definicja szkoły wyższej, sposób formułowania nazw poszczególnych szkół, kwestia ich fuzji i podziałów, poszukiwanie oraz przypisywanie publikacji do autorów (instytucji)

    A Tough Metal‐Coordinated Elastomer: A Fatigue‐Resistant, Notch‐Insensitive Material with an Excellent Self‐Healing Capacity

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    Self-healing materials can prolong device life, but their relatively weak mechanical strength limits their applications. Introducing tunable metal-ligand interactions into self-healing systems can improve their mechanical strength. However, applying this concept to solid elastomers is a challenge. To address this need, polyurethane-containing metal complexes were fabricated by introduction of a pyridine-containing ligand into polyurethane, and subsequent coordination with Fe2+. The strong reversible coordination bond provides mechanical strength and self-healing ability. By optimizing the monomer ratio and Fe2+ content, the resulting complex possesses a very high tensile strength of 4.6MPa at strain of around 498% and a high Young's modulus (3.2MPa). Importantly, the metal complex exhibits an extremely high self-healing efficiency of approximately 96% of tensile strength at room temperature and around 30% at 5 degrees C. The complex is notch-insensitive and the fracture energy is 76186J/m(2), which is among the highest reported values for self-healing systems

    Fe/MOF based platform for NIR laser induced efficient PDT/PTT of cancer

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    Introduction: Photodynamic therapy (PDT) and photothermal therapy (PTT) are widely used in the treatment of tumors. However, their application in the treatment of clinical tumors is limited by the complexity and irreversible hypoxia environment generated by tumor tissues. To overcome this limitation, a nanoparticle composed of indocyanine green (ICG) and Fe-MOF-5 was developed.Methods: We prepared F-I@FM5 and measured its morphology, particle size, and stability. Its enzyme like ability and optical effect was verified. Then we used MTT, staining and flow cytometry to evaluated the anti-tumor effect on EMT-6 cells in vitro. Finally, the anti-tumor effect in vivo has been studied on EMT-6 tumor bearing mice.Results: For the composite nanoparticle, we confirmed that Fe-MOF-5 has the best nanozyme activity. In addition, it has excellent photothermal conversion efficiency and generates reactive oxygen species (ROS) under near-infrared light irradiation (808 nm). The composite nanoparticle showed good tumor inhibition effect in vitro and in vivo, which was superior to the free ICG or Fe-MOF-5 alone. Besides, there was no obvious cytotoxicity in major organs within the effective therapeutic concentration.Discussion: Fe-MOF-5 has the function of simulating catalase, which can promote the decomposition of excessive H2O2 in the tumor microenvironment and produce oxygen to improve the hypoxic environment. The improvement of tumor hypoxia can enhance the efficacy of PDT and PTT. This research not only provides an efficient and stable anti-tumor nano platform, but also has broad application prospects in the field of tumor therapy, and provides a new idea for the application of MOF as an important carrier material in the field of photodynamic therapy

    Monitoring multi-temporal and spatial variations of water transparency in the Jiaozhou Bay using GOCI data

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    Water transparency, commonly measured as Secchi disk depth (SDD), is essential for describing the optical properties of coastal waters. We proposed a regional linear corrected SDD estimation model based on the North Sea Mathematical Models for GOCI and the mechanical model developed by Lee et al. (2015) in the Jiaozhou Bay. Combined with the multiple variable linear regression analysis, the diurnal SDD variations of the bay inside and the bay mouth are controlled by the solar zenith angle (SZA) and tides. The bay outside mainly varies with SZA. From GOCI observations between 2011 and 2021, wind force influenced the entire area on the inner-annual SDD variations. It exhibits an increasing trend in the inter-annual dynamics, which was more stable inside the bay with an annual increase of 0.035 m, and air temperature was the most significant contribution. However, human activities cannot be ignored in causing water environment changes

    Unusual Electrical Conductivity Driven by Localized Stoichiometry Modification at Vertical Epitaxial Interfaces

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    Precise control of lattice mismatch accommodation and cation interdiffusion across the interface is critical to modulate correlated functionalities in epitaxial heterostructures, particularly when the interface composition is positioned near a compositional phase transition boundary. Here we select La1-xSrxMnO3 (LSMO) as a prototypical phase transition material and establish vertical epitaxial interfaces with NiO to explore the strong interplay between strain accommodation, stoichiometry modification, and localized electron transport across the interface. It is found that localized stoichiometry modification overcomes the plaguing dead layer problem in LSMO and leads to strongly directional conductivity, as manifested by more than three orders of magnitude difference between out-of-plane to in-plane conductivity. Comprehensive structural characterization and transport measurements reveal that this emerging behavior is related to a compositional change produced by directional cation diffusion that pushes the LSMO phase transition from insulating into metallic within an ultrathin interface region. This study explores the nature of unusual electric conductivity at vertical epitaxial interfaces and establishes an effective route for engineering nanoscale electron transport for oxide electronics

    Room-temperature multiferroic hexagonal LuFeO3_3 films

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    The crystal and magnetic structures of single-crystalline hexagonal LuFeO3_3 films have been studied using x-ray, electron and neutron diffraction methods. The polar structure of these films are found to persist up to 1050 K; and the switchability of the polar behavior is observed at room temperature, indicating ferroelectricity. An antiferromagnetic order was shown to occur below 440 K, followed by a spin reorientation resulting in a weak ferromagnetic order below 130 K. This observation of coexisting multiple ferroic orders demonstrates that hexagonal LuFeO3_3 films are room-temperature multiferroics

    Experiments on bright field and dark field high energy electron imaging with thick target material

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    Using a high energy electron beam for the imaging of high density matter with both high spatial-temporal and areal density resolution under extreme states of temperature and pressure is one of the critical challenges in high energy density physics . When a charged particle beam passes through an opaque target, the beam will be scattered with a distribution that depends on the thickness of the material. By collecting the scattered beam either near or off axis, so-called bright field or dark field images can be obtained. Here we report on an electron radiography experiment using 45 MeV electrons from an S-band photo-injector, where scattered electrons, after interacting with a sample, are collected and imaged by a quadrupole imaging system. We achieved a few micrometers (about 4 micrometers) spatial resolution and about 10 micrometers thickness resolution for a silicon target of 300-600 micron thickness. With addition of dark field images that are captured by selecting electrons with large scattering angle, we show that more useful information in determining external details such as outlines, boundaries and defects can be obtained.Comment: 7pages, 7 figure
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