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31.
Alfred M. Bruckstein Thomas J. Richardson 《Circuits, Systems, and Signal Processing》1998,17(3):361-389
A transform domain image tagging orwatermarking method that survives image cropping (and, hence, is holographic) was proposed at Bell Labs in September 1994. This report analyzed in detail the various properties of this method and introduces an optimal procedure for watermark recovery. 相似文献
32.
Wen-Yaw Chung Yeong-Tsair Lin Chung-Huang Yang Alfred Krzyskow 《Microelectronics Journal》2006,37(10):1105-1114
An integrated and new interface circuit with temperature compensation has been developed to enhance the ISFET readout circuit stability. The bridge-type floating source circuit suitable for sensor array processing has been proposed to maintain reliable constant drain-source voltage and constant drain current (CVCC) conditions for measuring the threshold voltage variation of ISFET due to the corresponding hydrogen ion concentration in the buffer solution. The proposed circuitry applied to Si3N4 and Al2O3-gate ISFETs demonstrate a variation of the drain current less than 0.1 μA and drain-source voltage less than 1 mV for the buffer solutions with the pH value changed from 2 to 12. In addition, the scaling circuitry with the VT temperature correction unit (extractor) and LABVIEW software are used to compensate the ISFET thermal characteristics. Experimental results show that the temperature dependence of the Si3N4-gate ISFET sensor improved from 8 mV/°C to less than 0.8 mV/°C. 相似文献
33.
Josef Eichinger Karl Heinz Mhrmann Jrg Sommer Wolfgang Zirwas Alfred Plattner Stefan Willke 《International Journal of Communication Systems》2001,14(3):319-331
Broadband networks using wireless transmission techniques are a quick and flexible means of implementing subscriber access. Unoccupied frequency bands with sufficient bandwidth to allow the transmission of digital signals at very high bit rates are found only in the microwave bands. Because the path loss is fairly high at these frequencies, the diameter of radio cells is limited to a maximum of a few kilometres. This results in a microcellular system, which is best implemented in the form of a point‐to‐multipoint system, where one radio‐base station serves all subscribers registered in that radio cell. An interactive, broadband, ATM‐based radio local loop has undergone successful trials in Munich. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
34.
Karl Speer Peter Horstmann Elke Steeg Thomas Kühn und Alfred Montag 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1990,191(6):442-448
Zusammenfassung Die Bestimmung der ubiquitär verbreiteten Polycyclen bereitet oftmals in Gemüseproben Schwierigkeiten. Vorgestellt werden daher Verfahren, mit denen man eine Abtrennung der störenden Stoffe wie etherische Öle, Wachse, Carotinoide und Chlorophylle erreicht. Als besonders geeignet erweist sich dabei die Reinigung der Probenextrakte an Bio Beads S-X3 und mittels der halbpräparativen HPLC an Kieselgel Si60. Die Polycyclen werden durch CGC/MS bestimmt. Hierdurch ist es möglich, neben den zu bestimmenden Analyten auch die zugesetzten deuterierten Standardverbindungen störungsfrei zu erfassen. Die Resultate 32 verschiedener Gemüseproben werden diskutiert. Höhere Gehalte findet man in Grünkohl- und Petersilienproben.
PAH analysis in vegetable samples
Summary PAH analyses in vegetables are often difficult to carry out; therefore two different clean-up methods, which allow elimination of interfering matrix components such as essential oils, waxes, carotinoids and chlorophylls were developed. Clean-up of 32 different vegetables samples consisted of either Bio-Beads S-X3 chromatography or semi-preparative HPLC on silica gel Si-60. PAH were determined by capillary GC-MS, which allowed the application of deuterium-labelled internal standards. The results are presented; higher PAH contamination was detected in cale and parsley.相似文献
35.
High‐Throughput Fabrication of Au–Cu Nanoparticle Libraries by Combinatorial Sputtering in Ionic Liquids 下载免费PDF全文
Dennis König Kai Richter Alexander Siegel Anja‐Verena Mudring Alfred Ludwig 《Advanced functional materials》2014,24(14):2049-2056
Materials libraries of binary alloy nanoparticles (NPs) are synthesized by combinatorial co‐sputter deposition of Cu and Au into the ionic liquid (IL) 1‐butyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide ([C1C4im][Tf2N]), which is contained in a micromachined cavity array substrate. The resulting NPs and NP‐suspensions are investigated by transmission electron microscopy (TEM), X‐ray diffraction (XRD), UV‐Vis measurements (UV‐Vis), and attenuated total reflection Fourier transformed infrared (ATR‐FTIR) spectroscopy. Whereas the NPs can be directly observed in the IL using TEM, for XRD measurements the NP concentration is too low to lead to satisfactory results. Thus, a new NP isolation process involving capping agents is developed which enables separation of NPs from the IL without changing their size, morphology, composition, and state of aggregation. The results of the NP characterization show that next to the unary Cu and Au NPs, both stoichiometric and non‐stoichiometric Cu–Au NPs smaller than 7 nm can be readily obtained. Whereas the size and shape of the alloy NPs change with alloy composition, for a fixed composition the NPs have a small size distribution. The measured lattice constants of all capped NPs show unexpected increased values, which could be related to the NP/surfactant interactions. 相似文献
36.
Potvin Alfred R. Crosier William G. Fromm Eli Lin James C. Neuman Michael R. Pilkington Theo C. Robinson Charles J. Schneider Lawrence W. Strohbehn John W. Szolovits Peter Tompkins Willis J. 《IEEE transactions on bio-medical engineering》1986,(1):48-59
MORE than 200 years ago, our forefathers made note of man's inalienable rights to life, liberty, and the pursuit of happiness. To the engineering community (applied science in the service of man), these may be coincident with applications to medicine and biology (biomedical engineering), defense, and entertainment. Biomedical engineering research has the distinction, among these three missions, of not only contributing to the quality of human life through the industrial economy but also to life itself?the most fundamental concern of all people. It is through biomedical engineering research that we have been able to learn much concerning the functioning of living systems, and it is through such knowledge that we have been able to develop improved clinical diagnosis, monitoring, and treatment, including life-sustaining devices and aids to the handicapped. Each step represents an improvement in the quality of life, and each step forms the foundation upon which to gain new knowledge to improve upon earlier developments. 相似文献
37.
D. Brynn Hibbert Alfred C. C. Tseung 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1979,29(12):713-722
The semiconducting perovskite oxide, La0.5Sr0.5CoO3, is a catalyst for the reduction of sulphur dioxide by carbon monoxide. Unlike aluminia-supported metal catalysts, La0.5Sr0.5CoO3 tolerates high levels of oxygen in the gas stream if sufficient carbon monoxide is present to react with all the oxygen. Water vapour (2%) does not adversely affect the reaction; unwanted byproducts H2S and COS are reduced for contact times less than 0.25 s. A computer model is used to predict equilibrium gas compositions for systems containing oxygen and water vapour. During the reaction the catalyst itself reacts with sulphur producing metal sulphides, possibly of simple cubic structure. The perovskite sulphides LaCoS3 and La0.5Sr0.5CoS3 are theoretically unstable. 相似文献
38.
This paper is an update of the overview given by Baker RC [Coriolis flowmeters: Industrial practice and published information. Flow Meas Instrum 1994;5(4):229–46]. Overviews about mass flowmetering are also given in Baker RC [Flow measurement handbook. Cambridge University Press; 2000]. Furthermore, Drahm W and Linnartz H [Coriolis-massflowmeters: State of the art review and innovations. In: Proceedings FLUCOME 2003. 2003] reported about latest innovations in Coriolis technology.
The published information of the last decade is reviewed and the conclusions of the different papers are briefly described. 相似文献
39.
Alfred Zeman 《Lubrication Science》1988,5(2):133-148
The versatility of a differential scanning calorimetry (DSC) cell in studying thermal and/or thermal-oxidative degradation of lubricants is shown using ester-based aviation turbine oils as an example. The following applications are discussed: 1. quality control of fresh and used oils by pressure differential scanning calorimetry; 2. influence of metal catalysis on oil degradation; 3. identification of volatile degradation products by PDSC gas chromatography-mass spectrometry via a TENAX trap; 4. determination of spontaneous ignition temperatures; 5. influence of metall metal oxides, wear debris and oil degradation products on ignition behaviour; 6. inhibition of spontaneous ignition by antioxidants. 相似文献
40.