565 research outputs found
A new phase with nano-rod structure evolved from ferroelectric thin film
No full textA new phase with nano-rod structure was synthesized during the heat treatment of the layered-perovskite material,
BaBi2Ta2O9. These nano-rod crystallites were well-oriented instead of lying on the surface. The X-ray diffractionXRD.
spectrum reveals that there is another phase formed when BaBi2Ta2O9is heated at 8008C. The d-spacings obtained from the
diffraction peaks of the second phase in the XRD spectrum were close to the results of the selected-area diffractionSAD.
patterns by transmission electron microscopyTEM.taken from the nano-rod crystallites. The high-resolution transmission
electron microscopyHRTEM.images also show that each nano-rod is a single crystal with 100 nm in length and 50 nm in
width approximately. These crystallites may be evolved from the interaction between the BaBi2Ta2O9 ferroelectric films
and the PtrTirSiO2rSi substrates at elevated temperatures
Ω-compact semigroups having congruence extension property
No full textAbstractThe congruence extension property (CEP) of semigroups has been extensively studied by a number of authors. We call a compact semigroup S an Ω-compact semigroup if the set of all regular elements of S forms an ideal of S. In this note, we characterize the Ω-compact semigroup having (CEP). Our result extends a recent result obtained by X.J. Guo on the congruence extension property of strong Ω-compact semigroups which is a semigroup containing precisely one regular D-class
Automated static and dynamic obstacle avoidance in arbitrary 3D polygonal worlds
No full textMediamaticsElectrical Engineering, Mathematics and Computer Scienc
Finding SHA-1 Characteristics: General Results and Applications
No full textsponsorship: We would like to thank Florian Mendel and Vincent Rijmen for many insightful discussions. The work described in this paper has been supported by the European Commission through the IST Programme under Contract IST-2002-507932 ECRYPT. The first author is supported by the Austrian Science Fund (FWF) project P18138. (European Commission through the IST Programme ECRYPT|IST-2002-507932, Austrian Science Fund (FWF)|P18138, Austrian Science Fund (FWF)|P18138)status: Publishe
Publisher Correction: A Co3O4-CDots-C3N4 three component electrocatalyst design concept for efficient and tunable CO2 reduction to syngas
No full textThe original HTML version of this Article omitted to list Yeshayahu Lifshitz as a corresponding author and incorrectly listed Shuit-Tong Lee as a corresponding author.Correspondingly, the original PDF version of this Article incorrectly stated that “Correspondence and requests for materials should be addressed to X.J. (email: [email protected]), or to Y.L. (email: [email protected]), or to S.-T.L. (email: [email protected]), or to Z.K. (email: [email protected])”, instead of the correct “Correspondence and requests for materials should be addressed to X.J. (email: [email protected]), or to Y. Liu (email: [email protected]), or to Y. Lifshitz (email: [email protected]), or to Z.K. (email: [email protected])”.This has now been corrected in the PDF and HTML versions of the Article.</jats:p
Experimental investigation on a thermoacoustic engine having a looped tube and resonator
No full textThe purpose of this paper is to study the impact of regenerator hydraulic radius, resonator length, and mean pressure on the characteristics of the tested thermoacoustic engine, which has a looped tube and resonator. Two different acoustic oscillations are observed in the tested engine [Yu ZB, Li Q, Chen X, Guo FZ, Xie XJ, Wu JH. Investigation on the oscillation modes in a thermoacoustic stirling prime mover: mode stability and mode transition. Cryogenics 2003;43(12):687–91]. In this paper, they are called two acoustic modes, high frequency mode (with a frequency independent of the resonator length) and low frequency mode (with a frequency depending on the resonator length). Experimental results indicate that the relative penetration depth (the ratio of penetration depth over hydraulic radius) plays an important role in the excitation and pressure amplitude of the two acoustic modes. For each tested regenerator hydraulic radius, there is a measured optimal relative penetration depth, which leads to the lowest onset temperature difference. Note that, in the tested engine, the measured optimal relative viscous penetration depths are in the range 3–5 (for low frequency mode). Furthermore, experimental results also show that the resonator length affects the presence of high frequency mode in this engine
Multi-Physics Driven Electromigration Study: Multi-Scale Modeling and Experiment
No full textThis dissertation presents a comprehensive and integrated study, including theory development, numerical simulation and experiment, for multi-physics driven electromigration in microelectronics. Multi-scale methodologies from atomistic modeling to continuum theory-based simulation have been developed. Moreover, extensive experimental testing, from testing wafer/die design and fabrication, sample preparation and process, to the measurement setup and characterization, has been conducted. The dissertation also provides synergetic and cohesive analysis between simulation and experiment. The simulation predictions and results have been well validated by experimental data.Electronic Components, Technology and Material
On the postprocessing removal of correlated errors in GRACE temporal gravity field solutions
No full textWe revisit the empirical moving window filtering method of Swenson and Wahr (Geophys Res Lett 33:L08402, 2006) and its variants, Chambers (Geophys Res Lett 33:L17603, 2006) and Chen et al. (Geophys Res Lett 34: L13302, 2007), for reducing the correlated errors in the Stokes coefficients (SCs) of the spherical harmonic expansion of the GRACE determined monthly geopotential solutions. Based on a comparison of the three published approaches mentioned, we propose a refined approach for choosing parameters of the decorrelation filter. Our approach is based on the error pattern of the SCs in the monthly GRACE geopotential solutions. We keep a portion of the lower degree-order SCs with the smallest errors unchanged, and high-pass filter the rest using a moving window technique, with window width decreasing as the error of the SCs increases. Both the unchanged portion of SCs and the window width conform with the error pattern, and are adjustable with a parameter. Compared to the three published approaches mentioned, our unchanged portion of SCs and window width depend on both degree and order in a more complex way. We have used the trend of mass change to test various parameters toward a preferred choice for a global compromise between the removal of the correlated errors and the minimization of signal distortion.Earth Observation and Space SystemsAerospace Engineerin
Denierella minutiserra Tan 1988
No full textDenierella minutiserra Tan, 1988 (Figs 5–6, 9, 12, 23–27) Denierella minutiserra Tan, 1988. Insects of Mt. Namjagbarwa region of Xizang: 289. Diagnosis. Male (Fig. 5). Body length 13–20 mm, maximal width on elytra 5.0–7.0 mm. Body pitch - black, entirely black pubescent, meso- and meta-femur and tibia ventrally with dense moderately long black setae. Head (Fig. 9) red, oily shiny, quadrate, coarsely and very densely punctuate. Antenna thick, reaching twothirds of the body, antennomere II slightly longer than wide. Pronotum coarsely and very densely punctate, surface between punctures opaque. All tarsal claws (Fig. 12) covered with minute teeth ventrally along dorsal blades. Metatibia with inner apical spur thin and pointed, outer one slightly shorter, flattened and blunt. Elytra obviously widened towards apex, humeri angled. External genitalia as in figs. 23–27. Female (Fig. 6). Antenna thinner, reaching the middle of body. Frons with impunctate areas very small. Meso- and metafemur and tibia ventrally without moderately long black setae. Type locality and material. “Xizang”. Holotype and Paratypes are deposited in the Institute of Zoology, Chinese Academy of Sciences, Beijing, P. R. China. Material examined. 1 male, 3 females, Tianlin (106 ° 14 'E, 24 ° 18 'N), Guangxi, 5 June 2002, X.J. Yang coll.; 10 males, 16 females, Dali (100 ° 19 'E, 25 ° 69 'N), Yunnan, 8–10 June 1998, B.Y. Mao coll.; 4 females, Lchun (10242 'E, 2301 'N), Yunnan, 28 July 2004, J. Li and C.X. Yuan coll.; 8 males, 11 females, Maguan (1044 'E, 2301 'N), Yunnan, 21 July 2006, Y.X. Yang coll.; 2 males, Wenshan (10424 'E, 2337 'N), Yunnan, 19 July 2006, Y.X. Yang coll.; 1 female, Jinping (10324 'E, 2277 'N), Yunnan, 24 July 2006, Y.X. Yang coll.. Distribution. CHINA: Xizang, Guangxi, and Yunnan.Published as part of Yang, Yu-Xia & Ren, Guo-Dong, 2007, Review of Chinese species of the genus Denierella Kaszab with a key to the worldwide species (Coleoptera, Meloidae), pp. 53-59 in Zootaxa 1642 on pages 57-58, DOI: 10.5281/zenodo.17968
Effectiveness and chemical pest control of Bt-cotton in the Yangtze River Valley, China
Full text linkThe sustainability of Bt-cotton in China, at least along Yellow River Valley, has been questioned, so this paper examines its effectiveness along Yangtze River Valley, where Bt-cotton is also widely sown, to determine what might be the factors beneath the limited or reduced effectiveness being observed. The analysis is based on the data collected for several years from many locations in the Yangtze River Valley Varietal Experiment Network to provide information on the varieties and their agronomic performance, on the control of their GM characteristic, on the expression of the Bt-gene and on chemical control practices against cotton pests.All varieties declared to be Bt-cotton were confirmed to have the Bt-gene, the expression of which was assessed in three ways: through the analysis of Bt-protein production and through indoor and outdoor bioassays. Gene expression varied substantially between varieties and between years for the few varieties which were tested in two subsequent years.The Bt-cotton varieties being sown cannot control bollworms totally even early in the growing season, so surviving larvae could inevitably be observed, and this led farmers (or professionals in charge of supplying technical assistance to farmers) to spray chemicals regardless of the real infestation level. This demonstrates behaviour aimed at eradication of the pests as bollworms seem to be treated chemically more often than is required and far earlier than necessary on the first two generations of H. armigera. The chemical control of the Bt-cotton in Yangtze River Valley hence is not optimal, thus farmers are paying high prices for varieties which are not totally resistant to bollworms and pest control costs are not reduced to the extent that they might expect, lowering the profitability of cotton production. Also chemical protection costs are not decreasing as those pests unaffected by the Bt-gene, mainly but not exclusively sucking ones are requiring more control. This is illustrative of a phenomenon of pest complex shift which deserves more attention in following up the Bt-cotton use.China; Bt; cotton; gene expression; chemical control; effectiveness
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