Two-tier relaxed heaps

We introduce a data structure which provides efficient heap operations with respect to the number of element comparisons performed. Let n denote the size of the heap being manipulated. Our data structure guarantees the worst-case cost of O(1) for finding the minimum, inserting an element, extracting an (unspecified) element, and replacing an element with a smaller element; and the worst-case cost of O(lg n) with at most lg n + 3 lg lg n + O(1) element comparisons for deleting an element. We thereby improve the comparison complexity of heap operations known for run-relaxed heaps and other worst-case efficient heaps. Furthermore, our data structure supports melding of two heaps of size m and n at the worst-case cost of O(min {lg m, lg n}). A preliminary version of this paper [8] was presented at the 17th International Symposium on Algorithms and Computation held in Kolkata in December 2006. Partially supported by the Danish Natural Science Research Council under contracts 21-02-0501 (project Practical data structures and algorithms) and 272-05-0272 (project Generic programming—algorithms and tools).     

移动和便携式电视系统的新纪元

在科技日新月异的今天,电视广播系统由模拟向数字的变迁已成为现实。预计在未来两年中,35％的电视将会以数字形式接收。除了家庭用的传统电视接收机外,消费者也期待便携式和移动电视接收机。移动电视接收的典型应用是车载电视,而便携式接收的典型应用是     

Polymeric thin films of controlled complex refractive index formedby the electrostatic self-assembled monolayer process

This letter reports a method, the electrostatic self-assembled monolayer process, for the synthesis of multilayer thin-film materials with controlled complex refractive index. By incorporating appropriate precursor molecules in each monolayer and organizing the physical order of the multiple monolayers through the material, it is possible to achieve designed complex refractive index properties. In this work, the real part of the refractive index of materials formed by this process was controlled from 1.424 to 1.615, and the imaginary part was controlled from 0.00001 to 0.035, both at a wavelength of 550 nm. To our knowledge, this is the first time that experimental measurements of self-assembled thin films are presented to demonstrate that this method is useful for the design and synthesis of thin films of controllable refractive index     

Modal dependence of the photoelastic coefficient in multimode,step-index optical fiber time domain systems

A simple ray-optic approach for the analysis of strained step-index multimode fibers is shown to lead to the determination of the photoelastic coefficient in an optical-fiber time-domain system. The theoretical model includes the dependence of the photoelastic coefficient a on the modal content of the fiber and explains some of the experimental discrepancies observed in high-resolution reentrant-loop-based sensing systems. For high-step-index 200-240 μm fibers with higher numerical resolution, the value of a is shown to vary from -0.2 to -0.3, which matches closely with experimental results     

Brookite Formation in TiO2?Ag Nanocomposites and Visible‐Light‐Induced Templated Growth of Ag Nanostructures in TiO2

TiO₂? Ag‐nanocomposites exhibit various desirable properties that make them suitable for a variety of applications, for example in photocatalysis and as bactericidal coatings. In this work, a new method for processing TiO₂? Ag nanocomposites is presented. The nanocomposite films are fabricated from one precursor solution with high silver loading of up to 50%. The resulting films exhibit a microstructure consisting of TiO₂? Ag_xO nanocomposites with a largely XRD‐amorphous TiO₂ matrix containing brookite nanocrystals. This specific microstructure absorbs in the visible range so that photoreduction of Ag ions can be accomplished by using visible light. The thin films can be patterned using simple shadow masks. The illuminated areas show a high density of self‐organized nanoparticles (SNPs) and nanorods (SNRs), which are templated by the TiO₂ porous network. The particle size can be tuned by varying the irradiation time. Most of the SNPs and SNRs form faceted crystals, which are mostly a combination of {111} and {110}. The application of these films as substrates for surface‐enhanced Raman scattering is shown. Enhancement factors as high as 4.6 × 10⁶ could be obtained using rhodamine 6G dye molecules. More applications should involve photocatalytic water purification using visible light.     

Adhesion and Mechanical Properties of PNIPAM Microgel Films and Their Potential Use as Switchable Cell Culture Substrates

Thermoresponsive poly(N‐isopropylacrylamide) (PNIPAM) microgel films are shown to allow controlled detachment of adsorbed cells via temperature stimuli. Cell response occurs on the timescale of several minutes, is reversible, and allows for harvesting of cells in a mild fashion. The fact that microgels are attached non‐covalently allows using them on a broad variety of (charged) surfaces and is a major advantage as compared to approaches relying on covalent attachment of active films. In the following, the microgels’ physico‐chemical parameters in the adsorbed state and their changes upon temperature variation are studied in order to gain a deeper understanding of the involved phenomena. By means of atomic force microscopy (AFM), the water content, mechanical properties, and adhesion forces of the microgel films are studied as a function of temperature. The analysis shows that these properties change drastically when crossing the critical temperature of the polymer film, which is the basis of the fast cell response upon temperature changes. Furthermore, nanoscale mechanical analysis shows that the films posses a nanoscopic gradient in mechanical properties.     

Non-destructive evaluations of water uptake in epoxy coating

A commercial epoxy coating was studied on steel panels and as free films to investigate water uptake using non-destructive techniques (gravimetric analysis, Electrochemical Impedance Spectroscopy [EIS], Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy [ATR-FTIR], and Scanning Acoustic Microscopy [SAM]) after immersion in 3.5 wt% NaCl solution. In epoxy free films, water uptake showed rapid absorption initially, slowing down due to the counteracting process between water uptake and leachable content. Later, a mass decrease indicated leaching dominance. On coated steel, EIS revealed rapid water absorption within 72 h, followed by slower uptake up to 336 h. The continuous increase in water content resulted from observed coating layer swelling, confirmed by SAM. ATR-FTIR analysis indicated hydrogen bonding of most absorbed water molecules to the epoxy matrix. By combining non-destructive techniques, water uptake mechanisms into the epoxy coating film were proposed.     

Involvement of glucocorticoids in testicular involution after active immunization of boars against GnRH

Active GnRH immunization of boars inhibits LH and testicular steroids but the consequences for spermatogenesis are unknown. Six boars were immunized three times against GnRH at 20, 24 and 28 weeks. Another six boars served as controls. Plasma LH and FSH were determined at 28 and 31 weeks. Testosterone and cortisol were determined before killing the pigs at 32 weeks. Tissue samples were taken for histology and fluid from the seminiferous tubuli for steroid determination. Individual germ cells were counted in histological sections. The glucocorticoid receptor (GCR), mitosis of spermatogonia and apoptosis were characterized by immunocytochemistry. Immunization reduced LH and testosterone to base levels whereas FSH was not changed. Testis weight was reduced by 64% due to a loss of Leydig cell cytoplasm (90.3%) and a decrease of tubule diameters (60.6%). Except for A-spermatogonia, all other spermatogenic cells were reduced by about 60%. Mitosis was reduced in immunized boars. Expression of GCRs was limited to spermatogonia and differed between immunized boars (8% of spermatogonia) and controls (2%). In the controls, androgen concentrations in tubular fluid were tenfold higher compared with immunized boars. Cortisol concentrations were of the order of 40 nmol/l both in the tubular fluid and blood plasma. These concentrations did not differ between groups. Apoptosis occurred only in spermatogonia and pachytene spermatocytes and was twofold higher in immunized boars compared with controls. Thus the availability of glucocorticoids in the tubuli and the expression of GCRs initiate apoptosis, which in turn reduces sperm yield. Testosterone is known to be an inhibitor of GCR expression, thus increasing the efficiency of spermatogenesis.