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排序方式: 共有264条查询结果,搜索用时 31 毫秒
211.
Wirth Wolfgang Eckstein Felix Kemnitz Jana Baumgartner Christian Frederik Konukoglu Ender Fuerst David Chaudhari Akshay Sanjay 《Magma (New York, N.Y.)》2021,34(3):337-354
Magnetic Resonance Materials in Physics, Biology and Medicine - To evaluate the agreement, accuracy, and longitudinal reproducibility of quantitative cartilage morphometry from 2D U-Net-based... 相似文献
212.
Uniform Luminous Perovskite Nanofibers with Color‐Tunability and Improved Stability Prepared by One‐Step Core/Shell Electrospinning
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Ping‐Chun Tsai Jung‐Yao Chen Ender Ercan Chu‐Chen Chueh Shih‐Huang Tung Wen‐Chang Chen 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(22)
A one‐step core/shell electrospinning technique is exploited to fabricate uniform luminous perovskite‐based nanofibers, wherein the perovskite and the polymer are respectively employed in the core and the outer shell. Such a coaxial electrospinning technique enables the in situ formation of perovskite nanocrystals, exempting the needs of presynthesis of perovskite quantum dots or post‐treatments. It is demonstrated that not only the luminous electrospun nanofibers can possess color‐tunability by simply tuning the perovskite composition, but also the grain size of the formed perovskite nanocrystals is largely affected by the perovskite precursor stoichiometry and the polymer solution concentration. Consequently, the optimized perovskite electrospun nanofiber yields a high photoluminescence quantum yield of 30.9%, significantly surpassing the value of its thin‐film counterpart. Moreover, owing to the hydrophobic characteristic of shell polymer, the prepared perovskite nanofiber is endowed with a high resistance to air and water. Its photoluminescence intensity remains constant while stored under ambient environment with a relative humidity of 85% over a month and retains intensity higher than 50% of its initial intensity while immersed in water for 48 h. More intriguingly, a white light‐emitting perovskite‐based nanofiber is successfully fabricated by pairing the orange light‐emitting compositional perovskite with a blue light‐emitting conjugated polymer. 相似文献
213.
In recent years, there has been an increasing trend towards using robots in production systems. Robots are used in different areas such as packaging, transportation, loading/unloading and especially assembly lines. One important step in taking advantage of robots on the assembly line is considering them while balancing the line. On the other hand, market conditions have increased the importance of mixed-model assembly lines. Therefore, in this article, the robotic mixed-model assembly line balancing problem is studied. The aim of this study is to develop a new efficient heuristic algorithm based on beam search in order to minimize the sum of cycle times over all models. In addition, mathematical models of the problem are presented for comparison. The proposed heuristic is tested on benchmark problems and compared with the optimal solutions. The results show that the algorithm is very competitive and is a promising tool for further research. 相似文献
214.
Akcöltekin E Peters T Meyer R Duvenbeck A Klusmann M Monnet I Lebius H Schleberger M 《Nature nanotechnology》2007,2(5):290-294
In the search to develop tools that are able to modify surfaces on the nanometre scale, the use of heavy ions with energies of several tens of MeV is becoming more attractive. Low-energy ions are mostly stopped by nuclei, which causes the energy to be dissipated over a large volume. In the high-energy regime, however, the ions are stopped by electronic excitations, and the extremely local (approximately 10 nm3) nature of the energy deposition leads to the creation of nanosized 'hillocks' or nanodots under normal incidence. Usually, each nanodot results from the impact of a single ion, and the dots are randomly distributed. Here we demonstrate that multiple, equally spaced dots, each separated by a few tens of nanometres, can be created if a single high-energy xenon ion strikes the surface at a grazing angle. By varying this angle, the number of dots, as well as their spacing, can be controlled. 相似文献
215.
Konukoglu E Acar B Paik DS Beaulieu CF Rosenberg J Napel S 《IEEE transactions on medical imaging》2007,26(12):1649-1656
Computer aided detection (CAD) in computed tomography colonography (CTC) aims at detecting colonic polyps that are the precursors of colon cancer. In this work, we propose a colon wall evolution algorithm polyp enhancing level sets (PELS) based on the level-set formulation that regularizes and enhances polyps as a preprocessing step to CTC CAD algorithms. The underlying idea is to evolve the polyps towards spherical protrusions on the colon wall while keeping other structures, such as haustral folds, relatively unchanged and, thereby, potentially improve the performance of CTC CAD algorithms, especially for smaller polyps. To evaluate our methods, we conducted a pilot study using an arbitrarily chosen CTC CAD method, the surface normal overlap (SNO) CAD algorithm, on a nine patient CTC data set with 47 polyps of sizes ranging from 2.0 to 17.0 mm in diameter. PELS increased the maximum sensitivity by 8.1% (from 21/37 to 24/37) for small polyps of sizes ranging from 5.0 to 9.0 mm in diameter. This is accompanied by a statistically significant separation between small polyps and false positives. PELS did not change the CTC CAD performance significantly for larger polyps. 相似文献
216.
217.
Ender Suvacı Yasemin Çelik Alicia Weibel Alain Peigney Emmanuel Flahaut 《Carbon》2012,50(8):3092-3095
Polycrystalline Fe-doped alumina (Al2O3) ceramics have been produced and used as a substrate for organized carbon nanotubes (CNTs) growth by catalytic chemical vapor deposition (CCVD). In these substrates, Fe3+ cations, which are the catalyst source, are initially substituted to Al3+ in α-Al2O3, instead of being simply deposited as a thin Fe layer on the surface of the substrate. The selective reduction of these substrates resulted in in situ formation of homogeneously distributed Fe nanoparticles forming patterns at nanometer-scale steps and kinks. These nanoparticles then catalyzed the growth of high quality CNTs, with some degree of organization thanks to their interaction with the topography of the substrate. 相似文献
218.
Ching-Fong Chen Timothy J. Baker Ron Synowicki Eric L. Tegtmeier Robert T. Forsyth Ashley L. Bissell Alex G. Orlowski James M. Christopher Ender Savrun 《Journal of the American Ceramic Society》2020,103(12):6666-6676
We report a high density MgO ceramic substrate produced by the tape casting technology. The tape casting formulation and process produced a uniform tape free of cracking. Y2O3 and SiO2 were used as the sintering aid for the pressureless sintering of the green tape. X-ray diffraction phase identification indicates that MgO is the main phase, while both Y2O3 and SiO2 sintering aids react with MgO to form MgY4Si3O13 as the second phase. Liquid phase sintering occurs in the temperature range from 1030°C to ~1500°C, which is confirmed by the simultaneous Thermal Gravitation Analysis/Differential Scanning Calorimeter (TGA/DSC) and the percent linear shrinkage and densification. A 96.5% theoretical density was achieved by presureless sintering at 1650°C for 2 hours, which was further increased to a fully dense structure using hot-isostatic-pressing(HIP) at 1650°C and 207 MPa in argon. Scanning electron microscopy (SEM) and energy dispersive(EDS) spectroscopic analysis on the HIP’ed sample show that MgY4Si3O13is located at the MgO grain boundary and the sample has a fully dense structure. The refractive indices and extinction coefficient were measured on the HIP’ed sample along with thermal properties and dielectric properties. Thermal diffusivity and heat capacity were measured to calculate the thermal conductivity. 相似文献
219.
Kamil B. Dermenci Tunç Yanık Sevinç Dağ Ender Suvacı Mehmet T. Kesim Umut Savacı Servet Turan 《International Journal of Applied Ceramic Technology》2020,17(4):1882-1890
ZnO-based anodes are currently possessing drawbacks such as their low cyclic stability, high capacity fade, and relatively low electronic conductivity that prevent their widespread use in commercial batteries. A commercially available, patented MicNo morphology of ZnO is known to adopt the advantages of nanosize into bulk in the field of semiconductor and cosmetic technology. In this study, the electrochemical performance of ZnO having MicNo morphology and its potential use in Li-ion batteries were investigated. After 100 galvanostatic cycles at constant 100 mA/g current density, the retained capacity of MicNo is higher than nanosized ZnO-the starting powder for MicNo ZnO. On the contrary, at higher current densities of 500 or 1000 mA/g, the nano-ZnO showed better cyclability and lower capacity fade compared to MicNo ZnO. In cyclic voltammetry results, reduction in ZnO, LiZn, and Li2Zn3 formation was dominant during formation cycle of MicNo ZnO along with excellent reversibility. After lithiation, phase change from crystalline ZnO into metallic Zn and amorphous ZnO was observed from transmission electron microscopy analysis. Improved Li+ diffusion in SEI and pore channels, better charge-transfer characteristics, poor electronic contact, and high EDL capacitance are other features of MicNo ZnO according to electrochemical impedance spectroscopy. 相似文献
220.
Feature Selection for Malware Detection on the Android Platform Based on Differences of IDF Values
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Journal of Computer Science and Technology - Android is the mobile operating system most frequently targeted by malware in the smartphone ecosystem, with a market share significantly higher than... 相似文献