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排序方式: 共有260条查询结果,搜索用时 46 毫秒
81.
Optical Review - The predictable quantum efficient detector (PQED) is a primary standard of optical power, which utilizes two custom-made induced-junction photodiodes that are mounted in a wedged... 相似文献
82.
Suvi Lehtimäki Sampo Tuukkanen Juho Pörhönen Pasi Moilanen Jorma Virtanen Mari Honkanen Donald Lupo 《Applied Physics A: Materials Science & Processing》2014,117(3):1329-1334
We report ecological and low-cost carbon nanotube (CNT) supercapacitors fabricated using a simple, scalable solution processing method, where the use of a highly porous and electrically conductive active material eliminates the need for a current collector. Electrodes were fabricated on a poly(ethylene terephthalate) substrate from a printable multi-wall CNT ink, where the CNTs are solubilized in water using xylan as a dispersion agent. The dispersion method facilitates a very high concentration of CNTs in the ink. Supercapacitors were assembled using a paper separator and an aqueous NaCl electrolyte and the devices were characterized with a galvanostatic discharge method defined by an industrial standard. The capacitance of the \(2\hbox { cm}^2\) devices was \(6\hbox { mF/cm}^2\) (2.3 F/g) and equivalent series resistance \(80\,\Omega \) . Low-cost supercapacitors fabricated from safe and environmentally friendly materials have potential applications as energy storage devices in ubiquitous and autonomous intelligence as well as in disposable low-end products. 相似文献
83.
Erkki Kolehmainen Juha Koivukorpi Elina Sievänen Vladimír Král 《Supramolecular chemistry》2013,25(6):437-441
A series of novel receptors showing high binding affinity in aqueous media for biologically important anions are reported. These naturally chromophoric porphyrin-based receptors contain cholic acids connected via quaternary alkyl ammonium amido linkages. 相似文献
84.
The Fermi-liquid theory formulated by Landau is a basic paradigm of the behavior of an interacting many-body system. We present a new application of this theory to calculate the "Landau force" on a macroscopic object. We show that immersing a pendulum in a Fermi liquid can increase its oscillation frequency, and evidence of this has been observed in mixtures of (3)He and (4)He. 相似文献
85.
Characterization of silane layers on modified stainless steel surfaces and related stainless steel-plastic hybrids 总被引:1,自引:0,他引:1
Mari Honkanen Maija HoikkanenMinnamari Vippola Jyrki VuorinenToivo Lepistö Petri JussilaHarri Ali-Löytty Markus LampimäkiMika Valden 《Applied Surface Science》2011,257(22):9335-9346
The aim of this work was to characterize silane layers on the modified stainless steel surfaces and relate it to the adhesion in the injection-molded thermoplastic urethane-stainless steel hybrids. The silane layers were characterized with scanning electron microscope and transmission electron microscope, allowing the direct quantization of silane layer thickness and its variation. The surface topographies were characterized with atomic force microscope and chemical analyses were performed with X-ray photoelectron spectroscopy. The mechanical strength of the respective stainless steel-thermoplastic urethane hybrids was determined by peel test. Polishing and oxidation treatment of the steel surface improved the silane layer uniformity compared to the industrially pickled surface and increased the adhesion strength of the hybrids, resulting mainly cohesive failure in TPU. XPS analysis indicated that the improved silane bonding to the modified steel surface was due to clean Fe2O3-type surface oxide and stronger interaction with TPU was due to more amino species on the silane layer surface compared to the cleaned, industrially pickled surface. Silane layer thickness affected failure type of the hybrids, with a thick silane layer the hybrids failed mainly in the silane layer and with a thinner layer cohesively in plastic. 相似文献
86.
Impact of Metal Ions in Porphyrin‐Based Applied Materials for Visible‐Light Photocatalysis: Key Information from Ultrafast Electronic Spectroscopy 下载免费PDF全文
Prasenjit Kar Samim Sardar Dr. Erkki Alarousu Dr. Jingya Sun Prof. Zaki S. Seddigi Prof. Saleh A. Ahmed Dr. Ekram Y. Danish Dr. Omar F. Mohammed Prof. Samir Kumar Pal 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(33):10475-10483
Protoporphyrin IX‐zinc oxide (PP‐ZnO) nanohybrids have been synthesized for applications in photocatalytic devices. High‐resolution transmission electron microscopy (HRTEM), X‐ray diffraction (XRD), and steady‐state infrared, absorption, and emission spectroscopies have been used to analyze the structural details and optical properties of these nanohybrids. Time‐resolved fluorescence and transient absorption techniques have been applied to study the ultrafast dynamic events that are key to photocatalytic activities. The photocatalytic efficiency under visible‐light irradiation in the presence of naturally abundant iron(III) and copper(II) ions has been found to be significantly retarded in the former case, but enhanced in the latter case. More importantly, femtosecond (fs) transient absorption data have clearly demonstrated that the residence of photoexcited electrons from the sensitizer PP in the centrally located iron moiety hinders ground‐state bleach recovery of the sensitizer, affecting the overall photocatalytic rate of the nanohybrid. The presence of copper(II) ions, on the other hand, offers additional stability against photobleaching and eventually enhances the efficiency of photocatalysis. In addition, we have also explored the role of UV light in the efficiency of photocatalysis and have rationalized our observations from femtosecond‐ to picosecond‐resolved studies. 相似文献
87.
V. Koponen J. Äystö J. Honkanen P. Jauho H. Penttilä J. Suhonen P. Taskinen K. Rykaczewski J. Żylicz C. N. Davids 《Zeitschrift für Physik A Hadrons and Nuclei》1989,333(4):339-348
Neutron-rich isotopes of palladium were produced via the fission of238U by 20 MeV protons. These isotopes were selected using the ion guide-fed on-line mass-separator facility IGISOL at Jyväskylä. Their decays were studied byβ-ray,γ-ray and conversion-electron spectroscopy. For114Pd and116Pd, the decay schemes established previously were confirmed; additionally multipolarities were determined for a few transitions. In the case of118Pd, only an approximate half-life was known from a previous radiochemical experiment. In the present study, 15 gamma transitions were observed, most of which were placed in a decay scheme. The half-life and the decay energy were found to beT 1/2=1.9±0.1 s andQ β=4.0±0.2 MeV. The decay schemes of114Pd,116Pd and118Pd include — respectively — two, two and four 0+→1+ Gamow-Teller beta transitions with logft values between 4.1 and 5.1. The strength of these transitions is discussed in terms of the extreme single particle shell model with pairing and the spherical proton-neutron quasiparticle random phase approximation. The possible role of deformation is considered using a shell correction method. Predictions for the decay properties of the as yet unobserved120Pd are given. 相似文献
88.
Erkki Mäkinen 《BIT Numerical Mathematics》1989,29(3):572-575
This paper shows that a binary tree can be constructed from its preorder and inorder traversals in linear time and space. 相似文献
89.
Summary Multidimensional gas chromatography-mass spectrometry (GC/GC/MS) was used for the determination of coplanar PCB congeners in biological samples. A quadrupole low resolution mass spectrometer was used as the main detector in order to increase the reliability of identification and enable the use of 13C-labelled internal standards. The technique was capable to separate these toxic congeners from the complex matrix and decreased the need of sample purification. 相似文献
90.
We present a new index for approximate string matching. The index collects text q-samples, that is, disjoint text substrings of length q, at fixed intervals and stores their positions. At search time, part of the text is filtered out by noticing that any occurrence of the pattern must be reflected in the presence of some text q-samples that match approximately inside the pattern. Hence the index points out the text areas that could contain occurrences and must be verified. The index parameters permit load balancing between filtering and verification work, and provide a compromise between the space requirement of the index and the error level for which the filtration is still efficient. We show experimentally that the index is competitive against others that take more space, being in fact the fastest choice for intermediate error levels, an area where no current index is useful. 相似文献