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991.
With video compression standards such as MPEG‐4, a transmission error happens in a video‐packet basis, rather than in a macroblock basis. In this context, we propose a semantic error prioritization method that determines the size of a video packet based on the importance of its contents. A video packet length is made to be short for an important area such as a facial area in order to reduce the possibility of error accumulation. To facilitate the semantic error prioritization, an efficient hardware algorithm for face tracking is proposed. The increase of hardware complexity is minimal because a motion estimation engine is efficiently re‐used for face tracking. Experimental results demonstrate that the facial area is well protected with the proposed scheme. 相似文献
992.
993.
Coating of 0.65Pb(Mg1/3Nb2/3)O3–0.35PbTiO3 (PMN–PT) relaxor ferroelectrics by a sol–gel method is followed by growth of epitaxial SrRuO3 (SRO) metallic oxide electrodes on SrTiO3 (STO) single-crystal substrate by pulsed laser deposition. High-quality PMN–PT films on SRO with preferred growth orientation were successfully fabricated by controlling the operation parameters. Structural properties of relaxor ferroelectric PMN–PT thin films on SRO/STO substrates have been studied by X-ray diffraction (XRD), transmission electron microscopy (TEM) and atomic force microscopy (AFM). In-plane and out-of-plane alignments of the heterostructure are confirmed and the structural twinning of the materials are also revealed. 相似文献
994.
悬浮床加氢裂化油溶性催化剂与沥青质的作用 总被引:1,自引:1,他引:0
在高压釜反应器中对添加了油溶性 Ni 催化剂(UPC-O)和水溶性 Ni 催化剂(UPC-W)的辽河稠油常压渣油(LHAR)进行了悬浮床加氢裂化实验。通过元素分析和傅里叶变换红外光谱(FTIR)分析对抑制反应生焦效果好的 UPC-O 与 LHAR 沥青质的作用进行了研究。元素分析结果显示,在 LHAR 中加入 UPC-O1000μg/g,沥青质和脱沥青质油中 Ni 含量分别出476μg/g和110μg/g 增加到7 559μg/g 和1 024μg/g,表明 UPC-O 在沥青质中有富集的趋势。FTIR 表征结果显示,UPC-O 和沥青质发生了相互作用。UPC-O 可在沥青质原位硫化为活性组分,对沥青质在悬浮床加氢裂化反应中的缩合起到好的抑制作用。 相似文献
995.
Barbara K. Reck Robert B. Gordon 《JOM Journal of the Minerals, Metals and Materials Society》2008,60(7):55-59
Nickel and chromium are essential ingredients in alloys increasingly important for energy-efficient, environmentally friendly
modern technology. Quantitative assessment of the flows of these metals through the world economy from resource extraction
to final disposal informs resource policy, energy planning, environmental science, and waste management. This article summarizes
the worldwide technological cycles of nickel and chromium in 2000. Stainless steel is the major use of these metals, but they
serve numerous other special needs, as in superalloys for high-temperature service, as plating materials, and in coinage.
Because they are used primarily in alloys, novel recycling issues arise as their use becomes more widespread.
“... the great New York and St. Louis double track, nickel plated railroad...”
— Norwalk, Ohio, Chronicle 10 March 1881 announces arrival of surveyors for the future Nickel Plate Railway
“Later [1911] I formed an alloy of Iron and Chromium, which showed remarkable resistance to rust and tarnish ... [It was]
rediscovered by an Englishman named Brearley, in 1914.”
—Elwood Haynes to Stephen F. Roberts, 17 January 1925 相似文献
996.
Kwang-Chul Noh Hyeon-Cheol Lee Dae-Young Kim Myung-Do Oh 《Electronics Packaging Manufacturing, IEEE Transactions on》2008,31(2):143-149
Practical studies on the method of contamination control for yield enhancement in the cellular phone modules production line were carried out. A contamination control method was proposed, consisting of data collection, data analysis, improvement action, verification, and implementation of control. The partition check method and the composition analysis for data collection and data analysis were respectively used in the cellular phone modules manufacturing process, and these methods were evaluated by the variation of yield loss before and after implementing the actions for improvement. In the partition check method, the critical process step was selected, and yield loss reduction through improvement actions was observed, whereas in the composition analysis, critical sources were selected, and yield loss reduction through improvement actions was investigated. From the results, it is concluded that the partition check and the composition analysis are effective solutions for contamination control in cleanroom production lines. 相似文献
997.
Shafeeque G. Ansari Mushtaq Ahmad Dar Young-Soon Kim Hyung-Kee Seo Gil-Sung Kim Rizwan Wahab Zubaida A. Ansari Jae-Myung Seo Hyung-Shik Shin 《Korean Journal of Chemical Engineering》2008,25(3):593-598
A comparative study for the nucleation of diamond was carried out using surface treatment like (i) surface scratching with
1 μm diamond paste and (ii) surface etching using chlorine plasma at different RF powers (50, 100 and 150 W). Atomic force
microscopic study shows variation in roughness from 31 nm to 110 nm. Scratching results in random scratches, whereas plasma
etches a surface uniformly. Scanning electron microscopic observations show well faceted crystallites with a predominance
of angular shaped grains corresponding to 〈100〉 and 〈110〉 crystallite surfaces for the scratched as well as plasma etched
substrate. Surface etching at 150 W plasma power results in a better growth in comparison with 50 and 100 W plasma powers.
Chlorine-radical is found responsible for the changes in the growth morphology. Raman spectroscopy shows a sharp peak at 1,332
cm−1 and a peak at ∼1,580 cm−1 for both samples. 相似文献
998.
999.
Mold-slag friction and fracture may cause heat-transfer variations in continuous casting, which leads to steel shell temperature
and stress variations, resulting in surface cracks. Analytical transient models of liquid slag flow and solid slag stress
have been coupled with a finite-difference model of heat transfer in the mold, gap, and steel shell to predict transient shear
stress, friction, slip, and fracture of the slag layers. The models are validated by comparing with numerical models and plant
measurements of mold friction. Using reported slag-fracture strength and time-temperature-transformation (TTT) diagrams, the
models are applied to study the effect of casting speed and mold-powder viscosity properties on slag-layer behavior between
the oscillating mold wall and the solidifying steel shell. The study finds that liquid-slag lubrication would produce negligible
stresses. A lower mold-slag consumption rate leads to high solid friction and results in solid-slag-layer fracture and movement
below a critical value. Crystalline slag tends to fracture near the meniscus and glassy slag tends to fracture near the mold
exit. A medium casting speed may be the safest to avoid slag fracture, due to its having the lowest critical lubrication consumption
rate. The high measured friction force in operating casters could be due to three sources: an intermittent moving solid slag
layer, excessive mold taper, or mold misalignment.
Other symbols are defined in Table I 相似文献
1000.
Pipe piles can be classified as either closed- or open-ended piles. In the present paper, the load capacity of both closed- and open-ended piles is related to cone penetration resistance qc through an experimental program using calibration chamber model pile load tests and field pile load tests. A total of 36 calibration chamber pile load tests and two full-scale field pile load tests were analyzed. All the test piles were instrumented for separate measurement of each component of pile load capacity. Based on the test results, the normalized base resistance qb/qc was obtained as a function of the relative density DR for closed-ended piles, and of both the relative density DR and the incremental filling ratio (IFR) for open-ended piles. A relationship between the IFR and the relative density DR is proposed as a function of the pile diameter and driving depth. The relationship between IFR and DR allows the estimation of IFR and thus of the pile load capacity of open-ended piles at the design stage, before pile driving operations. 相似文献