1,721,153 research outputs found
One-dimensional silicon nitride grating refractive index sensor suitable for integration with CMOS detectors
Full text linkThe transformation of nanophotonic sensors from laboratory-based demonstrations to a portable system to ensure widespread applicability in everyday life requires their integration with detectors for direct electrical read out. As complementary metal oxide semiconductor (CMOS) technology has revolutionized the electronics industry, the integration of nanophotonic structures with CMOS technology will also transform the sensing market. However, nanophotonic sensors have to fulfill certain requirements for their integration with CMOS detectors, such as operation in the visible wavelength range, operation in normal incidence configuration, use of CMOS compatible materials, and capability to give large optical intensity change due to resonance wavelength shift. In this paper, we have designed and developed one-dimensional silicon nitride grating structures that satisfy all these conditions simultaneously. The gratings can achieve 1 and 6 nm linewidths for the transverse-electric (TE) and transverse-magnetic (TM) polarizations, respectively, with 90% resonance depth. The experimental linewidth is 8 nm with 55% resonance depth, which is limited by the detector resolution. The experimental sensitivity of the device is 160 nm/refractive index unit (RIU), which translates to a very high intensity sensitivity of 1700%/RIU, which would enable sensing of very small changes in refractive index when integrated with a detector
Towards portable nanophotonic sensors
Full text linkA range of nanophotonic sensors composed of different materials and device configurations have been developed over the past two decades. These sensors have achieved high performance in terms of sensitivity and detection limit. The size of onchip nanophotonic sensors is also small and they are regarded as a strong candidate to provide the next generation sensors for a range of applications including chemical and biosensing for point-of-care diagnostics. However, the apparatus used to perform measurements of nanophotonic sensor chips is bulky, expensive and requires experts to operate them. Thus, although integrated nanophotonic sensors have shown high performance and are compact themselves their practical applications are limited by the lack of a compact readout system required for their measurements. To achieve the aim of using nanophotonic sensors in daily life it is important to develop nanophotonic sensors which are not only themselves small, but their readout system is also portable, compact and easy to operate. Recognizing the need to develop compact readout systems for onchip nanophotonic sensors, different groups around the globe have started to put efforts in this direction. This review article discusses different works carried out to develop integrated nanophotonic sensors with compact readout systems, which are divided into two categories; onchip nanophotonic sensors with monolithically integrated readout and onchip nanophotonic sensors with separate but compact readout systems
Metabolomics on CMOS for personalised medicine
No full textThe emergence of personalised and precision healthcare requires detailed knowledge of human molecular pathology. Genomics has been transformed by sequencing technologies that can unravel the human genome in 1 day for less than a thousand dollars. Recently, metabolomics, the quantitative measurement of small molecules, has emerged as a field to study an individual’s molecular profile. This is very important because a genome can only give a prediction of an individual’s propensity to a disease – genotyping, while a metabolome can provide immediate diagnosis of biochemical activity in human body – phenotyping. However, the present approach of measuring metabolites depends on large and expensive equipment such as NMR spectroscopy and mass spectroscopy. More importantly, this equipment does not provide a single analytical platform to measure the entire metabolome. CMOS technology has made a major impact in personal mobile computing, digital imaging and communications as part of everyday life. CMOS provides a single integrated platform for sensing technologies, low-cost manufacturing and miniaturisation of microelectronic systems. CMOS has been used successfully to create an all-electronic sequencing technology. We anticipate that CMOS has the potential to allow multiple biomarkers to be monitored in parallel, thus paving the way for metabolome profiling. This review will provide a background to personalised medicine, in terms of genomics and metabolomics, to show the importance for future healthcare delivery. A theoretical background of enzymes for metabolite quantification will also be discussed. A description of DNA microarray technologies will be provided. A background of CMOS chemical sensor systems will be presented for DNA sequencing and metabolite quantification. Finally, a discussion of future CMOS sensor systems, microelectronics and integration technologies that could lead to new “omics” technologies, will be given
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Cumming, David
No full textSee entry in Mobile County, volume 1, page 96: https://digital.archives.alabama.gov/digital/collection/voter1867/id/228
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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