Almost exact modelling assumption in adaptive linear control

Modem adaptive controllers are known to give bounded solutions when the system ‘normalized’ unmodelled effects are bounded by a small constant. This paper studies this unusual characterization of uncertainties. We show it encompasses more classical approaches. We discuss how feedback and by-passing may allow this assumption to be satisfied. We conclude by proposing the notion of almost exactly linearly modelled systems.     

Evaluation of calibration methods for a helicopter-borne microwave scatterometer

The French frequency modulated continuous waves (FMCW) scatterometer ERASME mounted on small helicopter or aircraft has been designed as dualfrequency (C and X bands) and dualpolarization (HH, VV) to investigate simultaneously the vegetation and the soil responses in radar backscattering. It is operated as a forward looking radar with a large elevation beamwidth (± 10° at 3 db) to observe easily the same surface target over a large range of incidence angles during a single flight. By this ability, ERASME is a complementary research tool for intercalibration of airborne and spaceborne imaging Synthetic Aperture Radars like Radarsat and ASAR and has to be well calibrated in every configuration, both absolutely and relatively for comparisons at different incidence angles.

This paper evaluates different calibration methods to be applied to such an instrument. Absolute calibration within 1 dB is easily obtained by external calibration using metallic corner reflectors. But this method remains insufficient to get the antenna elevation aperture which is essential on natural distributed targets for antenna pattern correction, due to the severe constraint of a narrow azimuthal beam and flight parameters (pitch, roll, altitude) varying quickly in time and range.

The external calibration is strongly improved by using a statistical analysis of data obtained over natural targets which analyses the correlation between the processed data and the recorded flight parameters. This method appears promising, but its application on natural targets with random variations need specific statistical properties of the data set. It is operative for high antenna setting (here 38° incidence angle) and mostly over bare soils, with low of σ⁰ variances and σ² correlation length of the order of the correlation length of pitch. It provides the aperture range around the antenna axis and an accuracy of 0.5 dB upon erσ⁰ is achieved providing the antenna pattern correction are done.     

熔盐电解精炼提纯金属硅(英文)

对熔盐电解质中硅的沉积过程进行电化学研究。在 973~223K,在硅氯化物熔盐中采用电解精炼提纯金属硅。结果表明,液态硅铜合金阳极有利于 CaCl2-NaCl-CaO-Si 熔盐体系的电解精炼。ICP-AES 分析结果显示,通过电解精炼可有效去除原料中大量的钛、铝、铁等金属杂质,硅中的硼和磷含量分别由 36×106和 25×106降低至 4.6×10 6和 2.8×10 6,电解能耗约为 9.3 kW·h/kg。     

Imaging techniques for observing laminar geometry in the feather shaft cortex

By being at the interface of the exocytic and endocytic pathways, the plant trans-Golgi network (TGN) is a multitasking and highly diversified organelle. Despite governing vital cellular processes, the TGN remains one of the most uncharacterized organelle of plant cells. In this review, we highlight recent studies that have contributed new insights and to the generation of markers needed to answer several important questions on the plant TGN. Several drugs specifically affecting proteins critical for the TGN functions have been extremely useful for the identification of mutants of the TGN in the pursuit to understand how the morphology and the function of this organelle are controlled. In addition to these chemical tools, we review emerging microscopy techniques that help visualize the TGN at an unpreceded resolution and appreciate the heterogeneity and dynamics of this organelle in plant cells.     

Effect of Phytic Acid on the In-Vitro Rate of Digestibility of Rapeseed Protein and Amino Acids

Phytic acid in rapeseed flour was reduced by pH adjustment to 5.15 with subsequent dialysis or by phytase treatment at pH 5.15 with subsequent dialysis. The effect of phytate reduction on the rate and extent of protein and amino acid digestibilities was then determined using an in vitro pepsin-pancreatin proteolysis method with simultaneous dialysis of reaction products. A 51% reduction in phytic acid increased the rate of release of many essential amino acids but a further 89% reduction in phytic acid did not enhance that effect. Phytate removal did not improve the protein digestibility.     

Forward Light Cuts: A Scalable Approach to Real‐Time Global Illumination

We present Forward Light Cuts, a novel approach to real‐time global illumination using forward rendering techniques. We focus on unshadowed diffuse interactions for the first indirect light bounce in the context of large models such as the complex scenes usually encountered in CAD application scenarios. Our approach efficiently generates and uses a multiscale radiance cache by exploiting the geometry‐specific stages of the graphics pipeline, namely the tessellator unit and the geometry shader To do so, we assimilate virtual point lights to the scene's triangles and design a stochastic decimation process chained with a partitioning strategy that accounts for both close‐by strong light reflections, and distant regions from which numerous virtual point lights collectively contribute strongly to the end pixel. Our probabilistic solution is supported by a mathematical analysis and a number of experiments covering a wide range of application scenarios. As a result, our algorithm requires no precomputation of any kind, is compatible with dynamic view points, lighting condition, geometry and materials, and scales to tens of millions of polygons on current graphics hardware.     

A THEORETICAL STUDY OF THE INFLUENCE OF THE ELECTRIC FIELD AND POLARIZATION DISTRIBUTIONS ON FERROELECTRIC THIN FILMS SWITCHING PROPERTIES

ABSTRACT

One of the essential criteria for the material evaluation for high speed applications such as ferroelectric memories is the switching speed as a function of the applied field. Theoretically the kinetics of switching in bulk and films have often been modeled using models derived from the Kolmogorov Avrami theory. Because some important aspects of thin films are not possible to take into account within this framework, we have adopted another approach based of a time-dependent Ginzburg-Landau model. The present work is devoted to investigating the influence of the surface effect and the bound charges field on the switching properties.     

束流真空管道中放电现象的实验研究

目前正在欧洲核子中心(CERN)建造的LHC(Large Hadron Collider)是世界上最大的加速器,它是一个具有高能量(7 TeV)大流强(0.53 A)的质子加速器.在它的直线节真空系统中,绝大部分的真空盒内表面将被镀上NEG薄膜.这样在又细又长的真空盒里,当有束流通过时,NEG薄膜不仅可以作为分布式吸气剂泵使用,而且NEG薄膜还具有降低二次电子发射系数的作用,因此了解NEG薄膜的性能是很重要的.