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1.
Branislav Radjenovi? Jae Koo Lee Marija Radmilovi?-Radjenovi? 《Computer Physics Communications》2006,174(2):127-132
Level set method [S. Osher, J. Sethian, J. Comput. Phys. 79 (1988) 12] is a highly robust and accurate computational technique for tracking moving interfaces in various application domains. It originates from the idea to view the moving front as a particular level set of a higher dimensional function, so the topological merging and breaking, sharp gradients and cusps can form naturally, and the effects of curvature can be easily incorporated. The resulting equations, describing interface surface evolution, are of Hamilton-Jacobi type and they are solved using techniques developed for hyperbolic equations. In this paper we describe an extension of the sparse field method for solving level set equations in the case of non-convex Hamiltonians, which are common in the simulations of the profile surface evolution during plasma etching and deposition processes. Sparse field method itself, developed by Whitaker [R. Whitaker, Internat. J. Comput. Vision 29 (3) (1998) 203] and broadly used in image processing community, is an alternative to the usual combination of narrow band and fast marching procedures for the computationally effective solving of level set equations. The developed procedure is applied to the simulations of 3D feature profile surface evolution during plasma etching process, that include the effects of ion enhanced chemical etching and physical sputtering, which are the primary causes of the Hamiltonian non-convexity. 相似文献
2.
Zoran D. Zujovic Marija R. Gizdavic-Nikolaidis Paul A. Kilmartin Hicham Idriss Sanjaya D. Senanayake Graham A. Bowmaker 《Polymer》2006,47(4):1166-1171
The quantitative investigation of the radical scavenging properties of polyaniline (PANI) upon reaction with excess of the stable DPPH radical (a 4:1 ratio of DPPH to aniline units in the polymer) was carried out using 15N and 13C solid state NMR spectroscopy. During the process the polyaniline was oxidised so that the imine content increased from 45 to 65%. The extent of oxidation measured by NMR was confirmed by N1s XPS analysis. However, within a 30 min reaction time, about 85% of the DPPH radicals were scavenged as monitored by the decay in its EPR signal. This is about 20 times greater than the fraction of DPPH required to oxidize PANI from an imine content of 45-65%. An identification of further redox processes is required to explain the high degree of radical scavenging. At the same time, there was no evidence of significant chemical binding or trapping of DPPH in the PANI structure. 相似文献
3.
Slavkovik Marija Dennis Louise A. Fisher Michael 《Distributed and Parallel Databases》2015,33(1):3-31
Distributed and Parallel Databases - Crowdsourcing, together with its related approaches, has become very popular in recent years. All crowdsourcing processes involve the participation of a digital... 相似文献
4.
Hana Marko Janez Marina Santo Silvo Sre
o Marija 《Sensors and actuators. B, Chemical》2008,133(2):699-704
In this paper we present a novel approach to preparing large-displacement 65Pb(Mg1/3Nb2/3)O3–35PbTiO3/Pt (65/35 PMN–PT/Pt) bimorph actuators. These “substrate-free”, bending-type actuators were prepared by screen-printing the 65/35 PMN–PT and Pt thick-film pastes as the electrodes on alumina substrates. After this screen printing and the subsequent firing the 65/35 PMN–PT/Pt composites were peeled off from the substrates. Displacements of nearly 100 μm at 18 V were achieved for actuators with dimensions of 1.8 cm × 2.5 mm × 50 μm for the 65/35 PMN–PT layer. The normalized displacement (the displacement per unit length) was 40 μm/cm at 18 V. The experimental results together with a computation procedure were used to obtain the material parameters for a finite-element analysis of the 65/35 PMN–PT/Pt bimorph actuators. 相似文献
5.
Mario Kurtjak Marija Vukomanović Lovro Kramer Danilo Suvorov 《Journal of materials science. Materials in medicine》2016,27(11):170
Intensive research in the area of medical nanotechnology, especially to cope with the bacterial resistance against conventional antibiotics, has shown strong antimicrobial action of metallic and metal-oxide nanomaterials towards a wide variety of bacteria. However, the important remaining problem is that nanomaterials with highest antibacterial activity generally express also a high level of cytotoxicity for mammalian cells. Here we present gallium nanoparticles as a new solution to this problem. We developed a nanocomposite from bioactive hydroxyapatite nanorods (84?wt %) and antibacterial nanospheres of elemental gallium (16?wt %) with mode diameter of 22?±?11?nm. In direct comparison, such nanocomposite with gallium nanoparticles exhibited better antibacterial properties against Pseudomonas aeruginosa and lower in-vitro cytotoxicity for human lung fibroblasts IMR-90 and mouse fibroblasts L929 (efficient antibacterial action and low toxicity from 0.1 to 1?g/L) than the nanocomposite of hydroxyapatite and silver nanoparticles (efficient antibacterial action and low toxicity from 0.2 to 0.25?g/L). This is the first report of a biomaterial composite with gallium nanoparticles. The observed strong antibacterial properties and low cytotoxicity make the investigated material promising for the prevention of implantation–induced infections that are frequently caused by P. aeruginosa. 相似文献
6.
Marija Dakulovi?Author Vitae Ivan Petrovi? Author Vitae 《Robotics and Autonomous Systems》2011,59(5):329-342
Inspired by the Witkowski’s algorithm, we introduce a novel path planning and replanning algorithm — the two-way D∗ (TWD∗) algorithm — based on a two-dimensional occupancy grid map of the environment. Unlike the Witkowski’s algorithm, which finds optimal paths only in binary occupancy grid maps, the TWD∗ algorithm can find optimal paths in weighted occupancy grid maps. The optimal path found by the TWD∗ algorithm is the shortest possible path for a given occupancy grid map of the environment. This path is more natural than the path found by the standard D∗ algorithm as it consists of straight line segments with continuous headings. The TWD∗ algorithm is tested and compared to the D∗ and Witkowski’s algorithms by extensive simulations and experimentally on a Pioneer 3DX mobile robot equipped with a laser range finder. 相似文献
7.
Abstract A novel procedure for phase recovery from undersampled phaseshifted interferograms is described. First, synthetic interferograms are used to calculate the wrapped phase differences along two orthogonal directions. Second, they are unwrapped to recover the true Laplacian of the phase. The final step is to integrate the unwrapped phase differences to obtain the required phase. This method may be used with either path-independent or path-dependent phase unwrapping algorithms. The technique overcomes the sensitivity to noise of previous algorithms when low pass filtering techniques are applied during the calculation of the phase differences and least square methods are employed in the final step of phase integration. 相似文献
8.
Ultrastructural changes in the cemento‐enamel junction caused by acidic beverages: An in vitro study
Aleksandar D. Mitic Jovanka Z. Gasic Radomir G. Barac Goran S. Radenkovic Slavica M. Sunaric Jelena Z. Popovic Marija M. Nikolic 《Microscopy research and technique》2020,83(2):91-98
The present in vitro study was aimed at evaluating the morphological changes in the cemento‐enamel junction (CEJ) after exposure to acidic beverages using the scanning electron microscopy (SEM). The initial pH and titratable acidity (TA) was analyzed from follow groups: (I) Coca cola, (II) orange juice, (III) Cedevita, (IV) Red Bull, (V) Somersby cider, and (VI) white wine. The CEJ samples (n = 64), obtained from unerupted third molars, were allocated to one control (artificial saliva, n = 16) and six experimental groups (n = 8). The experimental samples were immersed in beverages (50 ml) for 15 min, three times daily, 10 days, and in artificial saliva between immersions. SEM analysis was performed in a blind manner, according to scoring scale. One‐way ANOVA and Tukey's post hoc tests, as well as Kruskal–Wallis and Mann–Whitney U test used for statistical analysis. The pH values of the acidic beverages ranged from 2.65 (Coca cola) to 3.73 (orange juice), and TA ranged from 1.90 ml (Coca cola) to 5.70 ml (orange juice) of NaOH to reach pH 7.0. The SEM analysis indicated statistically significant differences between the control samples and those immersed in acidic beverages. The Groups IV, I, and II, showed the highest CEJ damage grade while those of the Group VI were the lowest. All the tested acidic beverages caused morphological changes in the CEJ with a smaller or larger exposure of dentine surface, and were not always related to the pH or TA of acidic beverages. 相似文献
9.
Diana Meter Anita Racetin Katarina Vukojevi Marta Balog Vedrana Ivi Milorad Zjali Marija Heffer Natalija Filipovi 《International journal of molecular sciences》2022,23(11)
The aim of this study was to determine the effects of altered ganglioside composition on the expression of Cx37, Cx40, Cx43, Cx45, and Panx1 in different kidney regions of St8sia1 gene knockout mice (St8sia1 KO) lacking the GD3 synthase enzyme. Experiments were performed in twelve male 6-month-old mice: four wild-type (C57BL/6-type, WT) and eight St8sia1 KO mice. After euthanasia, kidney tissue was harvested, embedded in paraffin wax, and processed for immunohistochemistry. The expression of connexins and Panx1 was determined in different regions of the kidney: cortex (CTX.), outer stripe of outer medulla (O.S.), inner stripe of outer medulla (IN.S.), and inner medulla (IN.MED.). We determined significantly lower expression of Cx37, Cx40, Cx45, and Panx1 in different parts of the kidneys of St8sia1 KO mice compared with WT. The most consistent decrease was found in the O.S. where all markers (Cx 37, 40, 45 and Panx1) were disrupted in St8si1 KO mice. In the CTX. region, we observed decrease in the expression of Cx37, Cx45, and Panx1, while reduced expression of Cx37 and Panx1 was more specific to IN.S. The results of the present study suggest that deficiency of GD3 synthase in St8sia1 KO mice leads to disruption of renal Cx expression, which is probably related to alteration of ganglioside composition. 相似文献
10.
Niko Radulovi? Marija Deni? Zorica Stojanovi?-Radi? Danielle Skropeta 《Journal of the American Oil Chemists' Society》2012,89(12):2165-2185
The detailed analyses of the volatile essential oil and lipid profiles of the aerial parts from the blooming and fruit-forming stages of both ripe and unripe fruit of Lycopus europaeus (Lamiaceae) are presented. Both of these profiles are distinguished by components with a restricted occurrence in the Plant Kingdom. These rare compounds include (E)-hotrienol in the volatiles, numerous unusual fatty acids (such as very long chain, odd-numbered and branched-chain) in the bound lipids and a high amount of iso- and anteiso-alkanes in the epicuticular waxes. Furthermore, a Gaussian-like distribution of the relative amounts of the epicuticular wax alkanes was observed. These normal distributions could be interpreted as the end result of the work of elongase enzyme systems where the Gaussian parameter μ should match the length of the “ideal” fatty acid biosynthesised and σ would represent the error of this enzyme system. These curve parameters were shown to have a close relationship with ACL and CPI values usually utilised to describe the natural distribution of wax alkanes. The screening of L. europaeus essential oil for its in vitro antimicrobial activity showed that this oil possesses selectivity towards two gram-negative strains, E. coli and K. pneumoniae. 相似文献