1,720,957 research outputs found
Fabrication and testing of ISFET based pH sensors for microliter target solutions
No full textIn recent years, there has been an increasing interest in the monitoring and controlling of pH. It has become an important aspect of many industrial wastewater and water quality treatment processes. At the same time, the demand for smaller electronic devices used for various industrial, commercial, and research applications has greatly increased. In this paper, we propose a fabrication method of ion-sensitive field effect transistor (ISFET) using micro-electro-mechanical systems (MEMS) techniques for pH sensing application. The novelty of this device lies in the detection of target solution with volumes in the sub-microliter range. With proper electrical packaging, our ISFET chip has been able to detect the pH values of 2.5 μL solutions. The results reveal a linearity of pH measurement with a corresponding sensitivity of 10.7 mV-pH. Furthermore, Nernst equation is employed to analyze the performance, and a promising scheme to improve the sensitivity while measuring tiny solutions is proposed. This achievement has the potential to satisfy the research demands in various areas including chemistry, biology and medicine. © 2013 Elsevier B.V.BERGVELD P, 1970, IEEE T BIO-MED ENG, VBM17, P70, DOI 10.1109-TBME.1970.4502688; Bergveld P., 2003, P IEEE SENS C TOR CA, P26; Bergveld P, 2003, SENSOR ACTUAT B-CHEM, V88, P1, DOI 10.1016-S0925-4005(02)00301-5; Casey Jr H. C., 1999, DEVICES INTEGRATED C, P342; CHEN SC, 1986, J PHYS D APPL PHYS, V19, P1951, DOI 10.1088-0022-3727-19-10-020; Dong ZX, 2012, SENSOR ACTUAT A-PHYS, V173, P293, DOI 10.1016-j.sna.2011.10.029; HASHIM U, 2008, P IEEE INT C SEM EL; Jack W. J., 2001, SMART MATER STRUCT, V10, P1115; Jimenez-Jorquera C, 2010, SENSORS-BASEL, V10, P61, DOI 10.3390-s100100061; Lee CS, 2009, SENSORS-BASEL, V9, P7111, DOI 10.3390-s90907111; Zhuxin Dong, 2012, Applied Surface Science, V258, DOI 10.1016-j.apsusc.2012.05.07622
Multi level SVM for subject independent agitation detection
No full textThe need to automate the detection of agitation for dementia patients is a major requirement for caregivers. This research aims at detecting the agitation status of the subjects using soft computing techniques that does not require supervision beyond the training phase. An autonomous multi-sensory device has been developed to achieve automatic assessment of agitation and to control stimulation that will reduce the agitation level automatically. The focus of this paper is the agitation detection algorithm. Three vital signs are monitored for agitation detection: the Heart Rate (HR) the Galvanic Skin Response (GSR) and Skin Temperature (ST). These measures are fed into a new SVM architecture: The Multi level SVM learning machine. Results show very high detection accuracy of agitation, quick adaptation to the subject and a strong correlation between the physiological signals monitored and the emotional states of the subjects. The result is a learning algorithm that is Subject-Independent. ©2009 IEEE.American Psychiatric Association, 1994, DIAGN STAT MAN MENT; CULTER NR, 1996, UNDERSTANDING ALZHEI, P65; FOOK VFS, 2007, E HLTH NETW APPL SER, P68; Kecman V., 2001, LEARNING SOFT COMPUT; Kistler A, 1998, INT J PSYCHOPHYSIOL, V29, P35, DOI 10.1016-S0167-8760(97)00087-1; LIAO WH, 2005, IEEE COMP SOC C, V3, P70; Murray DR, 2003, CHEST, V123, P664, DOI 10.1378-chest.123.3.664; ROD K, 2000, INT J PSYCHOPHYSIOL, V37, P121; Rosenblatt Adam, 2005, Cleve Clin J Med, V72 Suppl 3, pS3; SAKR GE, 2008, ADV INT MECH IEEE AS; Tamura T., 1997, P 19 ANN INT C IEEE, V3, P999, DOI 10.1109-IEMBS.1997.756513; TULEN JHM, 1989, PHARMACOL BIOCHEM BE, V32, P9, DOI 10.1016-0091-3057(89)90204-9; *US BUR CENS, 2006, 65 US; Vapnik V.N., STAT LEARNING THEORY; Zhai J., 2006, FLAIRS C, P39532
Design, fabrication and testing of CNT based ISFET for NANO pH sensor application application: A preliminary study
No full textIn recent years, there has been increasing interest in monitoring and controlling of pH. It has become an important aspect of many industrial wastewater treatment processe processes. At the same time, the demand for sm smaller electronic devices used for aller various industrial and commercial applications has greatly increased. Micro and nano materials, icro such as Carbon Nanotubes (CNTs), are known for their excellent electrical and mechanical properties, as well as for their small size size, therefore they are good candidates to manufactur manufacture micro or nano e electronic devices. These devices can be used for pH control control. However, this cannot be achieved unless CNTs with metallic or semiconducting band structures can be successfully deposited and separated separated. In these processes, microchip fabrication and deposition of CNTs using Dielectrophoresis (DEP) are involved. Comparing with some traditional pH sensors, which mainly consist of Ion Ion-Sensitive Field Effect Transistor (ISFET), signal operational amplifier and Analog Digital Convert (ADC), Nano pH sensor with CNTs may provide more benefits owing to their unique properties. For example, 70 70-80percent of multi multi-walled CNTs (MWCNTs) are metallic and have high current density, which means this kind of micro device has e a linear relationship of I I-V char characteristic and can acteristic produce signal strong enough to make operational amplifying circuits unnecessary. In addition, to manufacture smaller devices more functional becomes possible as CNTs are tiny and compact. ©2009 IEEE
Characterization of vertically aligned carbon nanofibers grown on Ni dots nanoelectrode array using atomic force microscopy
No full textOne of the major limitations in the development of ultrasensitive electrochemical biosensors based on one-dimensional nanostructure is the difficulty involved with reliably fabricating nanoelectrode arrays (NEAs). In previous work, a simple, robust and scalable wafer-scale fabrication method to produce multiplexed biosensors is introduced. Each sensor chip consists of nine individually addressable arrays that uses electron beam patterned vertically aligned carbon nanofibers (VACNFs) as the sensing element. To ensure nanoelectrode behavior with higher sensitivity, VACNFs were precisely grown on 100 nm Ni dots with 1 μm spacing on each micro pad. However, in order to examine the quality and measure the height and diameter of the VACNFs, some surface detection and measurement tool at the nanoscale level is needed. In this paper, we introduce an approach to measure these nano-scale features through Atomic Force Microscope (AFM). With this method, both the 2D and 3D images of sample surface are generated and the sizes of carbon nanofibers and cavities are obtained. Furthermore, statistical analysis is carried out to enable improvement of VACNFs growth and fabrication. © 2009 IEEE
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Scanning and measurement of carbon nanofiber nanoelectrode arrays using atomic force microscopy
No full textOne of the major limitations in the development of ultrasensitive electrochemical biosensors based on one-dimensional nanostructure is the difficulty involved with reliably fabricating nanoelectrode arrays (NEAs). In previous work, a simple, robust and scalable wafer-scale fabrication method to produce multiplexed biosensors is introduced. Each sensor chip consists of nine individually addressable arrays that uses electron beam patterned vertically aligned carbon nanofibers (VACNFs) as the sensing element. To ensure nanoelectrode behavior with higher sensitivity, VACNFs were precisely grown on 100 nm Ni dots with 1μm spacing on each micro pad. However, in order to examine the quality and measure the height and diameter of the VACNFs, some surface detection and measurement tool at the nanoscale level is needed. In this paper, we introduce an approach to measure these nano-scale features through Atomic Force Microscope (AFM). With this method, both the 2D and 3D images of sample surface are generated and the sizes of carbon nanofibers and cavities are obtained. Furthermore, statistical analysis is carried out to enable improvement of VACNFs growth and fabrication. © 2009 IEEE
Variations on the Author
Get PDF“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
Get PDFWe 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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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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