10,000 publications from this institution
Although the electrical integration of chemically synthesized nanowires has been achieved with lithography, optical integration, which promises high speeds and greater device versatility, remains unexplored. We describe the properties and functions of individual crystalline oxide nanoribbons that act as subwavelength optical waveguides and assess their applicability as nanoscale photonic elements. The length, flexibility, and strength of these structures enable their manipulation on surfaces, including the optical linking of nanoribbon waveguides and other nanowire elements to form networks and device components. We demonstrate the assembly of ribbon waveguides with nanowire light sources and detectors as a first step toward building nanowire photonic circuitry.
The Internet architecture has proven its worth by the vast array of applications it now supports and the wide variety of network technologies over which it currently runs. Most current Internet research involves either empirical measurement studies or incremental modifications that can be deployed without major architectural changes. Easy access to virtual testbeds could foster a renaissance in applied architectural research that extends beyond these incrementally deployable designs.
This paper extends the theoretical model of the linkage between ethnoracial division and the penal state in the United States I have elaborated elsewhere (Wacquant 2001) to cover the stupendous surge in the incarceration of post-colonial migrants in the European Union over the past two decades, that is, the era of triumphant neoliberalism.
Abstract The nickel‐catalyzed amination of aryl chlorides to form primary arylamines occurs with ammonia or ammonium sulfate and a well‐defined single‐component nickel(0) precatalyst containing a Josiphos ligand and an η 2 ‐bound benzonitrile ligand. This system also catalyzes the coupling of aryl chlorides with gaseous amines in the form of their hydrochloride salts.
The solute‐vacancy interaction model (SVIM), which is an extension of the point‐defect model, has been utilized to investigate the effect of minor alloying on passivity breakdown. Experimental data of nickel binary alloys, aluminum binary alloys and Fe-Cr steels were used to calculate various SVIM parameters, and compare SVIM predictions to experimental observations. We found that the SVIM is capable to predict the effect of minor alloying on passivity breakdown potential for different alloying systems. Some systems showed an increase in pitting potential beyond the SVIM prediction, especially at high concentrations. This observation points to a different mechanism at higher concentrations, e.g., the formation of stable molybdates is a possible mechanism when the alloying concentration exceeds minor alloying, i.e., 3% wt. However, for lower concentrations, we postulate that the effect of the solute-vacancy interaction to be the most dominant.
Goal: Wertheimer (1923) proposed visual similarity as a key grouping factor but a precise definition has proved elusive. We formalize similarity by designing a function W(i,j) whose value is the probability that a pair of points i and j belong to the same visual group. Our goal is to learn an optimal functional form for W(i,j) based on brightness, texture and color measurements, and to quantify the relative power of these cues. Methods: A large dataset (∼1000) of natural images, each segmented by multiple human observers (∼10), provides the ground truth S(i,j) for pairs of pixels. S(i,j) = 1 if the pair lies in the same segment, 0 otherwise and will serve as the target function for W(i,j). We consider both region and boundary cues for computing W(i,j). Region cues are based on brightness, color, and texture differences between image patches at i and j, each characterized by histograms of the outputs of V1 like mechanisms. Oriented filter responses are used for texture and a*, b* features in CIE L*a*b* space for color. Boundary cues are incorporated by looking for the presence of an “intervening contour”, a large gradient (in brightness, texture or color) along a straight line connecting two pixels. The parameters of the patch and gradient features are calibrated using the human segmented images. Performance was evaluated on a separate test set using precision-recall curves as well as mutual information between W(i,j) and S(i,j) based on various cues. Results: For brightness, gradients yield better results than patch differences. However, for color, patches outperform gradients. Texture is the single most powerful cue, with both patches and gradients carrying significant independent information. The mutual information between S(i,j) and W(i,j) using all similarity cues is 0.19 nats, just 0.06 short of that between different human subjects. The proximity of the two pixels does not add any information beyond that provided by the similarity cues.
Abstract During the school closures in the beginning of 2021 many students and teachers found themselves making use of new remote educational technology. The use of an online chat function and breakout rooms became routine. Using observations during lessons, anonymised chat logs and a student questionnaire it is shown that there are positive outcomes for student voice and inclusion when using these features. The possibility for integration of a chat function in the physical classroom, to benefit students who are more confident in messaging than speaking, is briefly considered although a proper study of this was not possible at the time.
