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61.
A number of stereo matching algorithms have been developed in the last few years, which also have successfully detected occlusions in stereo images. These algorithms typically fall short of a systematic study of occlusions; they predominantly emphasize matching and regard occlusion filling as a secondary operation. Filling occlusions, however, is useful in many applications such as image-based rendering where 3D models are desired to be as complete as possible. In this paper, we study occlusions in a systematic way and propose two algorithms to fill occlusions reliably by applying statistical modeling, visibility constraints, and scene constraints. We introduce a probabilistic, model-based filling order of the occluded points to maintain consistency in filling. Furthermore, we show how an ambiguity in the interpolation of the disparity value of an occluded point can safely be avoided using color homogeneity when the point’s neighborhood consists of multiple scene surfaces. We perform a comparative study and show that statistically, the new algorithms deliver good quality results compared to existing algorithms. 相似文献
62.
Rong Yang Bing-Rui Lu Jing Xue Zhen-Kui Shen Zhen-Cheng Xu Ejaz Huq Xin-Ping Qu Yifang Chen Ran Liu 《Microelectronic Engineering》2010,87(5-8):824-826
Optic fluidic devices, which combine optical elements such as adaptive optical lenses or diffraction gratings into micro-fluidic devices, are now becoming increasingly important for environmental monitoring, medical diagnostics and chemical detection. In this paper, we present a novel and simple micro/nanofabrication process for SU-8 based optic fluidics structures with phase gratings on the bottom of the micro-channel using our silicon grating templates. The refraction index difference between the fluid and the SU-8 gratings generates a modulation in the phase of the light passing through the device. Our method of fabricating optic fluidic device is promising to be economic in fabrication, high throughput in production and have potential applications for sensing. 相似文献
63.
Bing-Rui Lu Jing Wan Zhen Shu Shen-Qi Xie Yifang Chen Ejaz Huq Xin-Ping Qu Ran Liu 《Microelectronic Engineering》2009,86(4-6):619-621
We report a novel nanoprocess combining nanoimprint lithography and conventional lithography to fabricate metallic and dielectric nanophotonic crystals with chiral elements in SU-8. The previously developed nanoimprint process was modified for much smaller feature size. Four different types of nanophotonic crystals with different materials in both large and small dimensions are fabricated. The new proposed reversal lithography is used to fabricate one type among the above mentioned four. The success of reversal lithography provides a solution for near-field lithography to achieve nanosize structures with simple conventional lithography. Optical measurements of the laser polarization state from the fabricated photonic crystals indicate an optical chirality which distinguishes the chiral elements from other normal symmetric structures. 相似文献
64.
Hasina F. Huq Syed K. Islam 《Journal of Infrared, Millimeter and Terahertz Waves》2005,26(11):1501-1512
The prime motivation for developing the proposed model of AlGaN/GaN microwave power device is to demonstrate its inherent ability to operate at much higher temperature. An investigation of temperature model of a 1 μm gate AlGaN/GaN enhancement mode n-type modulation-doped field effect transistor (MODFET) is presented. An analytical temperature model based on modified charge control equations is developed. The proposed model handles higher voltages and show stable operation at higher temperatures. The investigated temperature range is from 100 °K–600 °K. The critical parameters of the proposed device are the maximum drain current (IDmax), the threshold voltage (Vth), the peak dc trans-conductance (gm), and unity current gain cut-off frequency (fT). The calculated values of fT (10–70 GHz) at elevated temperature suggest that the operation of the proposed device has sufficiently high current handling capacity. The temperature effect on saturation current, cutoff frequency, and trans-conductance behavior predict the device behavior at elevated temperatures. The analysis and simulation results on the transport characteristics of the MODFET structure is compared with the previously measured experimental data at room temperature. The calculated critical parameters suggest that the proposed device could survive in extreme environments. 相似文献
65.
Zhonghe BiCraig A. Bridges Jung-Hyun KimAshfia Huq M. Parans Paranthaman 《Journal of power sources》2011,196(18):7395-7403
The electrical conductivity, crystal structure and phase stability of La0.99Ca0.01Nb1−xTaxO4−δ (x = 0, 0.1, 0.2, 0.3, 0.4 and 0.5, δ = 0.005), a potential candidate for proton conductor for solid oxide fuel cells (SOFCs), have been investigated using AC impedance technique and in situ X-ray powder diffraction. Partially substituting Nb with Ta elevates the phase transition temperature (from a monoclinic to a tetragonal structure) from ∼520 °C for x = 0 to above 800 °C for x = 0.4. AC conductivity of the La0.99Ca0.01Nb1−xTaxO4−δ both in dry and wet air decreased slightly with increasing Ta content above 750 °C, while below 500 °C, it decreased by nearly one order of magnitude for x = 0.4. It was also determined that the activation energy for the total conductivity increases with increasing Ta content from 0.50 eV (x = 0) to 0.58 eV (x = 0.3) for the tetragonal phase, while it decreases with increasing Ta content from 1.18 eV (x = 0) to 1.08 eV (x = 0.4) for the monoclinic phase. By removing the detrimental structural phase transition from the intermediate-temperature range, consequently avoiding the severe thermal expansion problem up to 800 °C, partial substitution of Nb with Ta brings this class of material closer to its application in electrode-supported thin-film intermediate-temperature SOFCs. 相似文献
66.
The effect of an oscillating normal force (fretting Mode II) on the degradation mechanism in an alumina versus a WC-Co ball-on-flat contact is presented. A sinusoidal oscillation of the normal force at a fixed frequency and normal force amplitude was applied for different numbers of cycles. The evolution of the surface damage with an increasing number of cycles at a constant force amplitude is reported. In general, wear is taking place in the slip region on alumina balls and on WC-Co flats. The oscillating normal force generates fatigue cracks on the surface of the alumina balls, but not on the WC-Co flats. Fatigue crack initiation life under fretting Mode II test conditions is evaluated for alumina in a plot of maximum normal load versus number of fretting cycles. 相似文献
67.
68.
Jung-Hyun Kim Young Nam Kim Zhonghe Bi Arumugam Manthiram M. Parans Paranthaman Ashfia Huq 《Electrochimica acta》2011,(16):5740
InBaCo4−xZnxO7 oxides have been synthesized and characterized as cathode materials for intermediate temperature solid oxide fuel cells (IT-SOFC). The effect of Zn substitution for Co on the structure, phase stability, thermal expansion, and electrochemical properties of the InBaCo4−xZnxO7 has been investigated. The increase in the Zn content from x = 1 to 1.5 improves the high temperature phase stability at 600 °C and 700 °C for 100 h, and chemical stability against a Gd0.2Ce0.8O1.9 (GDC) electrolyte. Thermal expansion coefficient (TEC) values of the InBaCo4−xZnxO7 (x = 1, 1.5, 2) specimens were determined to be 8.6 × 10−6 to 9.6 × 10−6/°C in the range of 80–900 °C, which provides good thermal expansion compatibility with the standard SOFC electrolyte materials. The InBaCo4−xZnxO7 + GDC (50:50 wt.%) composite cathodes exhibit improved cathode performances compared to those obtained from the simple InBaCo4−xZnxO7 cathodes due to the extended triple-phase boundary (TPB) and enhanced oxide-ion conductivity through the GDC portion in the composites. 相似文献
69.
AH Huq RS Lovell MJ Sampson WK Decker MB Dinulos CM Disteche WJ Craigen 《Canadian Metallurgical Quarterly》1996,36(3):530-534
Glycerol kinase (Gyk) participates in the metabolism of endogenously derived and dietary glycerol. Deficiency of the human enzyme activity is an X-linked recessive disorder with a clinical picture varying from childhood metabolic crisis to asymptomatic adults incidentally identified by hyperlipidemia screening (pseudohypertriglyceridemia). Gyk is a member of a small group of kinases termed ambiquitous enzymes that are found in the cytosol or as membrane-bound enzymes associated with the voltage-dependent anion channel of the mitochondrial outer membrane. It was recently reported that in humans there are X-linked and autosomal copies of Gyk sequences, both apparently functional genes and processed pseudogenes. To understand the role of Gyk in normal metabolism and the variable clinical features seen with Gyk deficiency, we have characterized the mouse Gyk gene. We present the sequence of a full-length mouse Gyk cDNA that is alternatively spliced in brain. The Gyk gene was mapped to the mouse X chromosome by both fluorescence in situ hybridization and an interspecies backcross panel, demonstrating conservation of synteny with dmd. To confirm the functional identity of the cDNA, transient transfection of the cDNA into COS7 cells was shown to cause a marked elevation in glycerol kinase activity. 相似文献
70.
Knappett PS Escamilla V Layton A McKay LD Emch M Williams DE Huq R Alam J Farhana L Mailloux BJ Ferguson A Sayler GS Ahmed KM van Geen A 《The Science of the total environment》2011,409(17):3174-3182
A majority of households in Bangladesh rely on pond water for hygiene. Exposure to pond water fecal contamination could therefore still contribute to diarrheal disease despite the installation of numerous tubewells for drinking. The objectives of this study are to determine the predominant sources (human or livestock) of fecal pollution in ponds and examine the association between local population, latrine density, latrine quality and concentrations of fecal bacteria and pathogens in pond water. Forty-three ponds were analyzed for E. coli using culture-based methods and E. coli, Bacteroidales and adenovirus using quantitative PCR. Population and sanitation spatial data were collected and measured against pond fecal contamination. Humans were the dominant source of fecal contamination in 79% of the ponds according to Bacteroidales measurements. Ponds directly receiving latrine effluent had the highest concentrations of fecal indicator bacteria (up to 106 Most Probable Number (MPN) of culturable E. coli per 100 mL). Concentrations of fecal indicator bacteria correlated with population surveyed within a distance of 30-70 m (p < 0.05) and total latrines surveyed within 50-70 m (p < 0.05). Unsanitary latrines (visible effluent or open pits) within the pond drainage basin were also significantly correlated to fecal indicator concentrations (p < 0.05). Water in the vast majority of the surveyed ponds contained unsafe levels of fecal contamination attributable primarily to unsanitary latrines, and to lesser extent, to sanitary latrines and cattle. Since the majority of fecal pollution is derived from human waste, continued use of pond water could help explain the persistence of diarrheal disease in rural South Asia. 相似文献