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91.
Lanthanide and Heavy Metal Free Long White Persistent Luminescence from Ti Doped Li–Hackmanite: A Versatile,Low‐Cost Material 下载免费PDF全文
Isabella Norrbo José M. Carvalho Pekka Laukkanen Jaakko Mäkelä Fikret Mamedov Markus Peurla Hanna Helminen Sari Pihlasalo Harri Härmä Jari Sinkkonen Mika Lastusaari 《Advanced functional materials》2017,27(17)
Persistent luminescence (PeL) materials are used in everyday glow‐in‐the‐dark applications and they show high potential for, e.g., medical imaging, night‐vision surveillance, and enhancement of solar cells. However, the best performing materials contain rare earths and/or other heavy metal and expensive elements such as Ga and Ge, increasing the production costs. Here, (Li,Na)8Al6Si6O24(Cl,S)2:Ti, a heavy‐metal‐ and rare‐earth‐free low‐cost material is presented. It can give white PeL that stays 7 h above the 0.3 mcd m?2 limit and is observable for more than 100 h with a spectrometer. This is a record‐long duration for white PeL and visible PeL without rare earths. The material has great potential to be applied in white light emitting devices (LEDs) combined with self‐sustained night vision using only a single phosphor. The material also exhibits PeL in aqueous suspensions and is capable of showing easily detectable photoluminescence even in nanomolar concentrations, indicating potential for use as a diagnostic marker. Because it is excitable with sunlight, this material is expected to additionally be well‐suited for outdoor applications. 相似文献
92.
93.
Jari Vartiainen Marjaana Rtt Raija Lantto Kalle Nttinen Eero Hurme 《Packaging Technology and Science》2008,21(6):317-328
Plasma‐activated biaxially oriented polypropylene (BOPP) films and paper substrate have been coated with functional chitosan solutions. Plasma treatment increased the amount of surface peroxide groups and carboxyl groups on the BOPP films. As a result of plasma activation, the surface energy increased from 30 to 50 dynes/cm. The enzyme tyrosinase catalysed the grafting of octyl gallate and dodecyl gallate to amino groups of chitosan polysaccharide. Resulting coatings exhibited strong antimicrobial activity against Gram‐positive Staphylococcus aureus and Gram‐negative Listeria innocua. After 24 h of incubation, a total reduction in both bacteria cell numbers varied between >4.9 and 1.4 logarithmic units. Grafted dodecyl gallate and octyl gallate at pH 6 were found to have the lowest reduction values of <3 logarithmic units for S. aureus, while 1.4 logarithmic reduction value was obtained for grafted dodecyl gallate at pH 6 against L. innocua. Chitosan coatings were also effective barrier layers against oxygen transmission although the transmission rates clearly increased in high‐humidity conditions. In dry conditions, however, the transmission rate of 2 cm3/(m2 · 24 h) was obtained with chitosan‐coated BOPP. Coatings did not have any effects on water vapour transmission. Both gallates were successfully grafted at pH 6. As increased flocculation and colour formation indicated, the tyrosinase‐catalysed grafting was more powerful with octyl gallate. Dodecyl gallate containing chitosan coatings was more hydrophobic as compared to octyl gallate. Total migration of substances into 95% ethanol was ≥5 mg/dm2, thus materials may be exploitable in packaging purposes in direct contact with certain foodstuffs. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
94.
We investigated orienting of attention by social and symbolic cues presented inside/outside the locus of attention. Participants responded to laterally presented targets preceded by simultaneously presented gaze and arrow cues. Participants’ attention was allocated to either of the cues and the other cue served as a distractor. In Experiments 1–4 nonpredictive cues were employed. The validity of the attended cue and distractor were varied orthogonally. Valid cues and distractors produced additive facilitation to reaction times when compared to invalid cues and distractors. The effects of gaze and arrow distractors were similar. When the cue was 100% valid and the distractor 50% valid (Experiment 5), distractor validity had no effect on reaction times. When realistic gaze and arrow cues were employed (Experiment 6), arrow but not gaze distractors influenced the reaction times. The results suggest that social and symbolic directional information can be integrated for attention orienting. The processing of social and symbolic directional information can be modulated by top-down control, but the efficiency of the control depends on the visual saliency of the cues. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
95.
Leo Ojala Nisse Husberg Teemu Tynjälä 《International Journal on Software Tools for Technology Transfer (STTT)》2001,3(4):382-393
A distributed dynamic channel allocation algorithm has been proposed in [11]. In this paper the algorithm is modelled using
predicate/transition nets. The same model can be used for any number of cell and channel configurations. The Maria reachability
analyser has been used to analyse the protocol for some configurations. These are deadlock-free and are shown to satisfy the
requirement that the same channel is never allocated to two neighbouring cells. The suitability of high-level nets for the
modelling and analysis of distributed algorithms is discussed.
Published online: 24 August 2001 相似文献
96.
Different break-in procedures for phosphoric acid doped polybenzimidazole membrane fuel cells (PBI-FC) have been studied, including voltage cycling and the use of constant current at different temperatures. A rapid break-in procedure consisting of high-temperature constant current break-in and relaxation has been developed. The break-in procedure is considered suitable for contamination and performance studies. 相似文献
97.
Vieno Piironen Jari Toivo Riitta Puupponen‐Pimi Anna‐Maija Lampi 《Journal of the science of food and agriculture》2003,83(4):330-337
The plant sterol contents of the most important vegetables, fruits and berries available in Finland were determined by capillary gas chromatography. The sample preparation procedure included both acid and alkaline hydrolysis to liberate sterols from their conjugates. The plant sterol contents of fresh vegetables ranged from 51 to 370 mg kg?1 fresh weight (fw) in samples obtained from retail sale. The highest contents (>300 mg kg?1) were measured in broccoli, Brussels sprouts, cauliflower and dill and the lowest (51 mg kg?1) in potato. The range of sterol contents on a dry weight (dw) basis was high, 246–4100 mg kg?1 dw. Considerable variation was also observed when individual samples of some vegetables were compared. Sitosterol was the main sterol (proportion 43–86%) in all vegetables except cucumber and spinach, in which Δ7‐sterols dominated. The total sterol contents were in the range 116–228 mg kg?1 fw in all fresh fruits except avocado, which contained more sterols, 752 mg kg?1 fw. In fresh berries the corresponding range was 60–279 m kg?1 fw. The wild berries lingonberry and blueberry were better plant sterol sources than the cultivated berries blackcurrant, redcurrant and strawberry. In fruits and berries the proportion of sitosterol ranged from 61–93% total sterols. On the basis of the results, the contribution of vegetables, fruits and berries to the total average daily plant sterol intake was estimated to be ca 60 mg. © 2003 Society of Chemical Industry 相似文献
98.
Saastamoinen T Tervo J Vahimaa P Turunen J 《Journal of the Optical Society of America. A, Optics, image science, and vision》2004,21(8):1424-1429
Conditions for exactly self-imaging nonparaxial fields that are periodic also in the transverse direction are introduced. The theory is first derived by assuming full coherence and then extended into the domain of partial coherence. Different types of solutions are discussed, and some illustrations of the existence of solutions and intensity distributions of the fields are presented. 相似文献
99.
Designing Fast Fourier Transform Accelerators for Orthogonal Frequency-Division Multiplexing Systems
Waqar Hussain Fabio Garzia Tapani Ahonen Jari Nurmi 《Journal of Signal Processing Systems》2012,69(2):161-171
Designing accelerators for the real-time computation of Fast Fourier Transform (FFT) algorithms for state-of-the-art Orthogonal Frequency-Division Multiplexing (OFDM) demodulators has always been challenging. We have scaled-up a template-based Coarse-Grain Reconfigurable Array device for faster FFT processing that generates special purpose accelerators based on the user input. Using a basic and a scaled-up version, we have generated a radix-4 and mixed-radix (2, 4) FFT accelerator to process different length and types of algorithms. Our implementation results show that these accelerators satisfy not only the execution time requirements of FFT processing for Single Input Single Output (SISO) wireless standards that are IEEE-802.11 a/g and 3GPP-LTE but also for Multiple Input Multiple Output (MIMO) IEEE-802.11n standard. 相似文献
100.
Hannu Kukka Vassilis Kostakos Timo Ojala Johanna Ylipulli Tiina Suopajärvi Marko Jurmu Simo Hosio 《Personal and Ubiquitous Computing》2013,17(1):15-27
We present a multipronged comparative study of citizens’ self-proclaimed information needs and actual information seeking behavior in smart urban spaces. We first conducted several user studies to identify the types of information services that citizens believed to be useful in urban setting utilizing methods ranging from contextual inquiry with lo-fi prototypes to “card sorting” exercise with a separate set of participants, and finally to implementing selected services. We then made a sizeable constructive intervention into the urban space by deploying in a city center 12 large, interactive public displays called “hotspots” to offer a wide range of previously identified information services. We collected comprehensive qualitative and quantitative data on the usage of the hotspots and their services by the general public during 13 months. Our study reveals discrepancies between a priori and a posteriori information seeking strategies extracted from the self-proclaimed information needs and the actual usage of the hotspots. 相似文献