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1.
Bioimaging: Shaping Luminescent Properties of Yb3+ and Ho3+ Co‐Doped Upconverting Core–Shell β‐NaYF4 Nanoparticles by Dopant Distribution and Spacing (Small 47/2017) 下载免费PDF全文
2.
Shaping Luminescent Properties of Yb3+ and Ho3+ Co‐Doped Upconverting Core–Shell β‐NaYF4 Nanoparticles by Dopant Distribution and Spacing 下载免费PDF全文
Aleksandra Pilch Christian Würth Martin Kaiser Dominika Wawrzyńczyk Michalina Kurnatowska Sebastian Arabasz Katarzyna Prorok Marek Samoć Wiesław Strek Ute Resch‐Genger Artur Bednarkiewicz 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(47)
At the core of luminescence color and lifetime tuning of rare earth doped upconverting nanoparticles (UCNPs), is the understanding of the impact of the particle architecture for commonly used sensitizer (S) and activator (A) ions. In this respect, a series of core@shell NaYF4 UCNPs doped with Yb3+ and Ho3+ ions are presented here, where the same dopant concentrations are distributed in different particle architectures following the scheme: YbHo core and YbHo@…, …@YbHo, Yb@Ho, Ho@Yb, YbHo@Yb, and Yb@YbHo core–shell NPs. As revealed by quantitative steady‐state and time‐resolved luminescence studies, the relative spatial distribution of the A and S ions in the UCNPs and their protection from surface quenching has a critical impact on their luminescence characteristics. Although the increased amount of Yb3+ ions boosts UCNP performance by amplifying the absorption, the Yb3+ ions can also efficiently dissipate the energy stored in the material through energy migration to the surface, thereby reducing the overall energy transfer efficiency to the activator ions. The results provide yet another proof that UC phosphor chemistry combined with materials engineering through intentional core@shell structures may help to fine‐tune the luminescence features of UCNPs for their specific future applications in biosensing, bioimaging, photovoltaics, and display technologies. 相似文献
3.
The paper addresses the problem of multi-slot just-in-time scheduling. Unlike the existing literature on this subject, it
studies a more general criterion—the minimization of the schedule makespan rather than the minimization of the number of slots
used by schedule. It gives an O(nlog 2
n)-time optimization algorithm for the single machine problem. For arbitrary number of m>1 identical parallel machines it presents an O(nlog n)-time optimization algorithm for the case when the processing time of each job does not exceed its due date. For the general
case on m>1 machines, it proposes a polynomial time constant factor approximation algorithm. 相似文献
4.
We study the problem of scheduling unit execution time jobs with release dates and precedence constraints on two identical
processors. We say that a schedule is ideal if it minimizes both maximum and total completion time simultaneously. We give
an instance of the problem where the min-max completion time is exceeded in every preemptive schedule that minimizes total
completion time for that instance, even if the precedence constraints form an intree. This proves that ideal schedules do
not exist in general when preemptions are allowed. On the other hand, we prove that, when preemptions are not allowed, then
ideal schedules do exist for general precedence constraints, and we provide an algorithm for finding ideal schedules in O(n
3) time, where n is the number of jobs. In finding such ideal schedules we resolve a conjecture of Baptiste and Timkovsky (Math. Methods Oper.
Res. 60(1):145–153, 2004) Further, our algorithm for finding min-max completion-time schedules requires only O(n
3) time, while the most efficient solution to date has required O(n
9) time. 相似文献
5.
Wies?aw Ostachowicz Marek Krawczuk Matthew Cartmell Michael Gilchrist 《Computers & Structures》2004,82(6):475-483
The wave propagation model investigated herein is based on the known fact that material discontinuities affect the propagation of elastic waves in solids. The change in certain material characteristics, such as a local change in stiffness or inertia caused by a crack or the presence of material damage, will affect the propagation of transmitted elastic waves and will modify the received signal. Wave frequencies associated with the highest detection sensitivity depend, among other things, on the type of structure, the type of material, and the type of damage. This paper presents a method of wave propagation, which can be further used to detect small delaminations in beam-like structures. The considered beam is modelled by spectral finite elements. 相似文献
6.
Grażyna Budryn Dorota Żyżelewicz Ewa Nebesny Joanna Oracz Wiesława Krysiak 《Food research international (Ottawa, Ont.)》2013,50(1):149-160
This study investigated the influence of antioxidants of green tea aqueous extract (GTE) and green coffee aqueous extract (GCE) in concentrations of 0.25, 0.5 and 1 g·100 g? 1 on the nutritional properties of fine yeast pastry fried products such as donuts. Yeast donuts were made according to the traditional processing technology. In fried donuts physical properties (water activity, pH, hardness and color with the use of instrumental methods) as well as sensory properties were established. Moreover, quality of fat extracted from donuts (composition of fatty acids and peroxide value), content of acrylamide, composition of polyphenols and antioxidant activity were analyzed. Obtained extracts of GTE and GCE contained 26 and 41% of polyphenols, respectively, and the degree of polyphenol degradation during production of donuts was less when the dilution in dough was greater. Both tests indicated that the highest antioxidant activity had donuts with the highest analyzed addition of extract, however depending on the applied test or GTE or GCE had better antioxidant properties. Fatty acid composition was the most beneficial when the addition of GTE and GCE was on a level of 0.25 and 0.5 g·100 g? 1, respectively. In fried donuts relatively low amounts of acrylamide were obtained, amounting to 18–46 μg·kg? 1. Only the lowest addition of GTE and the highest addition of GCE caused an increase of acrylamide content in donuts, while all other levels of added extracts caused a decrease in the content of formed acrylamide. 相似文献
7.
Colony-blot assay with anti-p60 antibodies as a method for quick identification of Listeria in food 总被引:2,自引:0,他引:2
Wieckowska-Szakiel M Bubert A Rózalski M Krajewska U Rudnicka W Rózalska B 《International journal of food microbiology》2002,72(1-2):63-71
The present study evaluated the ability to isolate Listeria from foods, using shortened procedure of sample enrichment followed by immunomagnetic separation or filtration methods, and serological identification of isolated bacteria by colony-blot and Western blot methods with anti-p60 antibodies. By these rapid methods, identification of Listeria was achieved in much shorter time (40-48 h) than with standard cultivation and biochemical identification procedures. The rapid methods used are easy to perform and, what is most important, their specificity is very high and fulfills the expectations. The possibility to select Listeria colonies growing on non-selective media by blotting with anti-p60 antiserum seems to be particularly valuable in examination of food samples containing/not too many Listeria (1-10 CFU/25 g). However, the blot method using anti-PepD mAb specific to unique region of L. monocytogenes p60 is necessary to distinguish L. monocytogenes from other Listeria species. 相似文献
8.
Monitoring of transient temperature and thermal stresses in pressure components of steam boilers 总被引:1,自引:0,他引:1
Jan Taler Bohdan W?glowski Wies?aw Zima S?awomir Gra?dziel Marcin Zborowski 《International Journal of Pressure Vessels and Piping》1997,72(3):231-241
Two methods of solving the transient inverse heat conduction problens in complex shaped elements are presented in this paper. The time-space temperature distribution in whole element cross-section is reconstructed using the measured temperature histories at several points placed inside the element or on its easily accessible outer surface. Thermal stresses are then evaluated involving Finite Element Analysis. In both methods the heat transfer coefficient at the element inner surface is the unknown value. Four examples are presented, two for one method showing the high accuracy of the presented methods and possibility of their practical application. 相似文献
9.
Martino Di Serio Riccardo Tesser Vincenzo Russo Rosa Turco Rosa Vitiello Yongqiang Sun Wiesław Hreczuch 《Journal of surfactants and detergents》2015,18(5):913-918
The intermediates for the production of nonionic surfactants can be derived from petrochemicals and/or from renewable raw materials. In both, the role of catalysis is fundamental. In this paper the main results reported in the literature related with the catalysis for ethoxylation of fatty esters will be reviewed. The main open challenges for these technologies will be outlined. 相似文献
10.
Monika Zab?ocka-Malicka Bart?omiej Ciechanowski Wies?aw Gawe? 《Electrochimica acta》2010,55(9):3409-3413
CsCl-NdCl3 is the next of binary MCl-NdCl3 systems (M: alkali metal) investigated for determination of relative internal mobilities of cations (bCs, bNd) by countercurrent electromigration method (Klemm's method). The results have been presented as isotherms of internal mobilities of Cs+ and Nd3+ ions on NdCl3 equivalent fraction (yNd). It has been found that internal mobility of cesium cations is higher than neodymium ones in the entire composition range (what is typical for nonsymmetrical MCl-LnCl3 systems (M: Li, Na, K; Ln: La, Nd, Dy)) and decreases with increase of NdCl3 concentration in the melt. Generally, dependence of internal mobility of lanthanide cations in melts with alkali metal chlorides on lanthanide (i.e. its atomic number and concentration) seems strongly related to stability of chloride complex anions of lanthanides in the melt. Investigated systems may be divided into two classes. The first class includes MCl-NdCl3 systems (M: Li, Na) characterized by decrease of bNd with increase of NdCl3 concentration. The second includes KCl-LnCl3 systems (Ln: La, Nd, Dy) and presented here CsCl-NdCl3 system, and is characterized by increase of bLn with concentration of Ln3+ cation. The dependence of bNd on NdCl3 concentration at 1073 K was fitted (as for other systems) by a simple equation of the form: , where is the internal mobility of Ln3+ cations in pure molten LnCl3, a the difference between internal mobility of Ln3+ cations in pure molten LnCl3 and infinitely diluted LnCl3 in molten alkali metal chloride (extrapolated), and yLnCl3 is the equivalent fraction of LnCl3. 相似文献