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81.
Hanne Hjorth Tønnesen Jan Karlsen Sitaram R. Adhikary Rita Pandey 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1989,189(2):116-118
Summary The content of curcuminoids inCurcuma longa L. before, during and after a normal harvesting period was investigated. The plant material was grown in the Kathmandu area. Bis-demethoxycurcumin was found to be the main constituent. No significant change in the curcuminoid content was observed during a 17-week sampling period.
Studien über Curcumin und Curcuminoide. XVII. Veränderung des Gehaltes an Curcuminoiden inCurcuma longa L. (Zingiberaceae) aus Nepal warend der Ernte
Zusammenfassung Der Gehalt an Curcuminoiden inCurcuma longa L. (Zingiberaceae) wurde vor, während und nach der normalen Erntezeit untersucht. Das Pflanzenmaterial stammt aus dim Kathmandu-Tal in Nepal. Der Hauptinhaltsstoff ist Bisdemethoxycurcumin. Im Laufe von 17 Wochen konnten keine signifikante Schwankungen observiert werden.相似文献
82.
83.
Syed Adeel Ali Shah Ejaz Ahmed Muhammad Ahsan Qureshi Sadeeq Jan Rafidah MD Noor 《International Journal of Communication Systems》2019,32(13)
In safety‐critical scenarios, reliable reception of beacons transmitted by a subject vehicle is critical to avoid vehicle collision. According to the employed contention window sizes in IEEE 802.11p, beacons are transmitted with a small contention window size. As a result, multiple vehicles contend for the shared channel access by selecting the same back‐off slot. This is a perfect recipe for synchronous collisions wherein reliable beacon delivery cannot be guaranteed for any vehicle. We consider the problem of selecting the back‐off slots from the current contention window to provide reliable delivery of beacons transmitted by a subject vehicle to its neighbors. Given a safety scenario, we propose a Pseudo‐Random Number Generator (PRNG)‐inspired back‐off selection (PBS) technique. The proposed technique works on the hypothesis that synchronous collisions of beacons transmitted by a subject vehicle can be reduced if all its neighbors select different back‐off slots (ie, not the back‐off slot selected by the subject vehicle). The discrete‐event simulations demonstrate that PBS can increase the overall message reception from a subject vehicle, in comparison with the uniform random probability back‐off selection in IEEE 802.11p. 相似文献
84.
85.
Wavelet-based reconstruction for limited-angle X-ray tomography 总被引:1,自引:0,他引:1
Rantala M Vänskä S Järvenpää S Kalke M Lassas M Moberg J Siltanen S 《IEEE transactions on medical imaging》2006,25(2):210-217
The aim of X-ray tomography is to reconstruct an unknown physical body from a collection of projection images. When the projection images are only available from a limited angle of view, the reconstruction problem is a severely ill-posed inverse problem. Statistical inversion allows stable solution of the limited-angle tomography problem by complementing the measurement data by a priori information. In this work, the unknown attenuation distribution inside the body is represented as a wavelet expansion, and a Besov space prior distribution together with positivity constraint is used. The wavelet expansion is thresholded before reconstruction to reduce the dimension of the computational problem. Feasibility of the method is demonstrated by numerical examples using in vitro data from mammography and dental radiology. 相似文献
86.
Hassan Elhadidy Jan Franc Eduard Belas Pavel Hlídek Pavel Moravec Roman Grill Pavel Hoschl 《Journal of Electronic Materials》2008,37(9):1219-1224
Thermoelectric effect spectroscopy and photoluminescence techniques were used to study the defect levels in samples from three
crystals of CdTe:In grown by the vertical gradient freeze method. The main goal of the investigation was to study defects,
which strongly trap charge carriers or act as recombination centers in order to eliminate them from the technological process.
The main difference among detecting and non-detecting samples was the absence of electron traps with a very high capture cross-section
and energy 0.6 eV to 0.7 eV, which act as lifetime killers even at low concentrations. Recently published ab initio calculations show a complex of Te antisite and Cd vacancy within this energy range. 相似文献
87.
Aykut Avci Jan De CockPeter Lambert Roel BeernaertJelle De Smet Lawrence BogaertYouri Meuret Hugo ThienpontHerbert De Smet 《Journal of Visual Communication and Image Representation》2012,23(2):287-292
An efficient disparity estimation algorithm for multi-view video sequences, recorded by a two-dimensional camera array in which the cameras are spaced equidistantly, is presented. Because of the strong geometrical relationship among views, the disparity vectors of a certain view can for most blocks be derived from the disparity vectors of other views. A frame constructed using that idea is called a D frame in this work. Three new prediction schemes which contain D frames are proposed for encoding 5 × 3 multi-view video sequences. The schemes are applied to several multi-view image sequences taken from a camera-array and they are compared in terms of quality, bit-rate and complexity. The experimental results show that the proposed prediction schemes significantly decrease the complexity of the encoder at a very low cost of quality and/or bit-rate. 相似文献
88.
Batteries: Carbon‐Based Anodes for Lithium Sulfur Full Cells with High Cycle Stability (Adv. Funct. Mater. 9/2014) 下载免费PDF全文
89.
Gonçalves SI de Munck JC Verbunt JP Bijma F Heethaar RM Lopes da Silva F 《IEEE transactions on bio-medical engineering》2003,50(6):754-767
In vivo measurements of equivalent resistivities of skull (rho(skull)) and brain (rho(brain)) are performed for six subjects using an electric impedance tomography (EIT)-based method and realistic models for the head. The classical boundary element method (BEM) formulation for EIT is very time consuming. However, the application of the Sherman-Morrison formula reduces the computation time by a factor of 5. Using an optimal point distribution in the BEM model to optimize its accuracy, decreasing systematic errors of numerical origin, is important because cost functions are shallow. Results demonstrate that rho(skull)/rho(brain) is more likely to be within 20 and 50 rather than equal to the commonly accepted value of 80. The variation in rho(brain)(average = 301 omega x cm, SD = 13%) and rho(skull)(average = 12230 omega x cm, SD = 18%) is decreased by half, when compared with the results using the sphere model, showing that the correction for geometry errors is essential to obtain realistic estimations. However, a factor of 2.4 may still exist between values of rho(skull)/rho(brain) corresponding to different subjects. Earlier results show the necessity of calibrating rho(brain) and rho(skull) by measuring them in vivo for each subject, in order to decrease errors associated with the electroencephalogram inverse problem. We show that the proposed method is suited to this goal. 相似文献
90.
Yurou Zhang Dohyung Kim Jung-Ho Yun Jongchul Lim Min-Cherl Jung Xiaoming Wen Jan Seidel Eunyoung Choi Mu Xiao Tengfei Qiu Miaoqiang Lyu EQ Han Mehri Ghasemi Sean Lim Henry J. Snaith Jae Sung Yun Lianzhou Wang 《Advanced functional materials》2021,31(50):2105542
Organometal perovskite single crystals have been recognized as a promising platform for high-performance optoelectronic devices, featuring high crystallinity and stability. However, a high trap density and structural nonuniformity at the surface have been major barriers to the progress of single crystal-based optoelectronic devices. Here, the formation of a unique nanoisland structure is reported at the surface of the facet-controlled cuboid MAPbI3 (MA = CH3NH3+) single crystals through a cation interdiffusion process enabled by energetically vaporized CsI. The interdiffusion of mobile ions between the bulk and the surface is triggered by thermally activated CsI vapor, which reconstructs the surface that is rich in MA and CsI with reduced dangling bonds. Simultaneously, an array of Cs-Pb-rich nanoislands is constructed on the surface of the MAPbI3 single crystals. This newly reconstructed nanoisland surface enhances the light absorbance over 50% and increases the charge carrier mobility from 56 to 93 cm2 V−1 s−1. As confirmed by Kelvin probe force microscopy, the nanoislands form a gradient band bending that prevents recombination of excess carriers, and thus, enhances lateral carrier transport properties. This unique engineering of the single crystal surface provides a pathway towards developing high-quality perovskite single-crystal surface for optoelectronic applications. 相似文献