Letteratura scientifica selezionata sul tema "Detectors"
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Articoli di riviste sul tema "Detectors"
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Blondel, Paul, Alex Potelle, Claude Pégard e Rogelio Lozano. "Collaborative training of far infrared and visible models for human detection". International Journal for Simulation and Multidisciplinary Design Optimization 10 (2019): A15. http://dx.doi.org/10.1051/smdo/2019016.
Testo completoAbstract (sommario):
This paper is about the collaborative training of a far infrared and a visible spectrum human detector; the idea is to use the strengths of one detector to fill the weaknesses of the other detector and vice versa. At first infrared and visible human detectors are pre-trained using initial training datasets. Then, the detectors are used to collect as many detections as possible. The validity of each detection is tested using a low-level criteria based on an objectness measure. New training data are generated in a coupled way based on these detections and thus reinforce both the infrared and the visible human detectors in the same time. In this paper, we showed that this semi-supervised approach can significantly improve the performance of the detectors. This approach is a good solution to generate infrared training data, this kind of data being rarely available in the community.
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AL-Rawi, Muhanned, e Muaayed AL-Rawi. "Combined Detector with Retraining Data Sequence". Technological Engineering 15, n. 1 (1 ottobre 2018): 47–50. http://dx.doi.org/10.1515/teen-2018-0009.
Testo completoAbstract (sommario):
Abstract Two detectors are presented in this paper which are used to handle intersymbol interference introduced by the communication channels. These two detectors are based on combination of nonlinear equalizer and Viterbi detector. The first detector, which was previously developed, is named Combined Detector1(CDR1), while, the second detector, which is the contribution of this paper, is named Combined Detector-2(CDR2). CDR2 is similar to CDR1 but with retraining data sequence. These detectors are tested beside nonlinear equalizer using data transmission at 9.6kb/s over telephone channel. Simulation results show that the performance of CDR2 is better than the performance of CDR1 while the performance of CDR1 is better than the performance of nonlinear equalizer.
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Martyniuk, P., e A. Rogalski. "Theoretical modelling of MWIR thermoelectrically cooled nBn HgCdTe detector". Bulletin of the Polish Academy of Sciences: Technical Sciences 61, n. 1 (1 marzo 2013): 211–20. http://dx.doi.org/10.2478/bpasts-2013-0020.
Testo completoAbstract (sommario):
Abstract The paper reports on the medium wavelength infrared (MWIR) unipolar barrier infrared detector (UBIRD) nBn/B-n type (n-type barrier) HgCdTe detector’s photoelectrical performance. The UBIRD nBn/B-n type HgCdTe detector was modelled using commercially available software APSYS. Detailed analysis of the detector’s performance (such as dark current, photocurrent, responsivity, and detectivity) versus bias voltage, operating temperatures, and structural parameters (cap, barrier, and absorber’s doping as well as cap and barrier compositions) were performed pointing out optimal working conditions. Both conduction and valence band alignments of the HgCdTe nBn/B-n type detector structure was simulated stressing their importance on detectors performance. It was shown that higher operation temperature (HOT) conditions achieved by commonly used thermoelectric (TE) coolers allow to obtain detectivities of D* = (3-10)×109 cmHz1/2/W at T = 200 K for detectors with cut-off wavelength of 5.2 μm The differential resistance area product of RA = 0.15-0.4 cm2 at T = 230 K for bias voltage V = 50 mV was estimated. Finally, the state of the art of UBIRD HgCdTe nBn/B-n type detector performance was compared to InAs/GaSb/B-Al0.2Ga0.8Sb T2SLs nBn detector, InAs/GaSb T2SLs PIN and the HOT HgCdTe bulk photodiodes’ operated at near-room temperature (T = 230 K). It was shown that the RA product of the MWIR UBIRD nBn/B-n type HgCdTe detector can reach a comparable level to the state of the art of the HgCdTe HOT bulk photodiodes and two types of type-II superlattice detectors: PIN photodiodes and nBn detectors
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Chen, Jiangtian. "Analysis of the Principle and Applications of Infrared Detectors in Cosmology". Highlights in Science, Engineering and Technology 72 (15 dicembre 2023): 793–99. http://dx.doi.org/10.54097/7g1bc173.
Testo completoAbstract (sommario):
As a matter of fact, infrared detectors are widely used and applied in cosmology detections. On this basis, this paper provides a comprehensive analysis of the principles and applications of infrared detectors in the field of cosmology. The paper discusses the two main types of infrared detectors: bolometer arrays and photon detector arrays, explaining their underlying principles and highlighting their applications in astronomy. It also presents the advancements in infrared detector technology, such as the use of different materials and the development of large-scale bolometer arrays. The paper further discusses the significant achievements made by various institutions in the field of infrared astronomy, including the discoveries based on detection result from SOFIA and WISE. Overall, this paper offers a comprehensive overview of the principles and applications of infrared detectors in cosmology, providing valuable information for enthusiasts in the field. These results shed light on guiding further exploration of space detectors.
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Koike, Ryuto, Masahiro Kaneko e Naoaki Okazaki. "OUTFOX: LLM-Generated Essay Detection Through In-Context Learning with Adversarially Generated Examples". Proceedings of the AAAI Conference on Artificial Intelligence 38, n. 19 (24 marzo 2024): 21258–66. http://dx.doi.org/10.1609/aaai.v38i19.30120.
Testo completoAbstract (sommario):
Large Language Models (LLMs) have achieved human-level fluency in text generation, making it difficult to distinguish between human-written and LLM-generated texts. This poses a growing risk of misuse of LLMs and demands the development of detectors to identify LLM-generated texts. However, existing detectors lack robustness against attacks: they degrade detection accuracy by simply paraphrasing LLM-generated texts. Furthermore, a malicious user might attempt to deliberately evade the detectors based on detection results, but this has not been assumed in previous studies. In this paper, we propose OUTFOX, a framework that improves the robustness of LLM-generated-text detectors by allowing both the detector and the attacker to consider each other's output. In this framework, the attacker uses the detector's prediction labels as examples for in-context learning and adversarially generates essays that are harder to detect, while the detector uses the adversarially generated essays as examples for in-context learning to learn to detect essays from a strong attacker. Experiments in the domain of student essays show that the proposed detector improves the detection performance on the attacker-generated texts by up to +41.3 points F1-score. Furthermore, the proposed detector shows a state-of-the-art detection performance: up to 96.9 points F1-score, beating existing detectors on non-attacked texts. Finally, the proposed attacker drastically degrades the performance of detectors by up to -57.0 points F1-score, massively outperforming the baseline paraphrasing method for evading detection.
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Wang, Mingyang, Zheng Li, Bo Xiong e Yongguang Xiao. "Electrical Characteristics of 3D Trench Electrode Germanium Detector with Nested Complementary Cathodes". Micromachines 14, n. 11 (1 novembre 2023): 2051. http://dx.doi.org/10.3390/mi14112051.
Testo completoAbstract (sommario):
High-purity germanium detectors, widely employed in fields such as aerospace applications based on radiation detection principles, have garnered attention due to their broad detection range and fast response time. However, these detectors often require larger sensitive area volumes to achieve larger signals and higher detection efficiency. Additionally, the large distance between the electrodes contributes to an issue of incomplete charge collection, which significantly restricts their application in space applications. To enhance the electrical performance of high-purity germanium detectors, this study introduces a strategy: designing the detector’s cathode electrode into a 3D trench shape with nested complementary cathodes. This design greatly reduces the electrode spacing, endowing the detector with superior electrical characteristics, such as a smaller dead zone and improved charge collection efficiency. Performance simulations of the novel detector structure were conducted using the semiconductor device simulation software Sentaurus TCAD (2019.03). The simulation results confirmed that the nested complementary 3D trench electrode high-purity germanium detector exhibits excellent electrical features, including a larger sensitive area volume, rapid charge collection, and good cell isolations. This approach has the potential to effectively expand the application scenarios of high-purity germanium detectors. Depending on different operational environments and requirements, nested complementary 3D trench electrode high-purity germanium detectors of appropriate structural dimensions can be chosen. The experimental findings of this study hold a significant reference value for enhancing the overall structure of high purity germanium detectors and facilitating their practical application in the future.
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Turunen, Vesa, Marko Kosunen, Sami Kallioinen, Aarno Pärssinen e Jussi Ryynänen. "The effects of non-linearity in spectrum sensing receivers". International Journal of Microwave and Wireless Technologies 8, n. 7 (15 luglio 2015): 995–1003. http://dx.doi.org/10.1017/s1759078715001130.
Testo completoAbstract (sommario):
This paper analyses the effects of receiver non-linearity on the performance of the most commonly utilized signal detectors in cognitive radio systems. The analysis covers both self-modulation products of a single orthogonal frequency-division multiplexing (OFDM) signal and intermodulation(IM)products of two OFDM signals, and also their contribution to the probability of false detections. As a result, this work presents the linearity requirements for the spectrum sensor receiver front-end as a function of the sensitivity of the signal detector. Furthermore, we show that the cyclostationary feature detectors are more robust than the energy detectors against IM products of multiple interferers. Theoretical results are verified in measurements with a cyclostationary feature detector using digital video broadcasting – terrestrial (DVB-T) signals as an example.
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Chi, Yao Dan, Di Yuan e Xiao Tian Yang. "Introduction to Intelligent Transportation Vehicle Detector". Applied Mechanics and Materials 496-500 (gennaio 2014): 1369–72. http://dx.doi.org/10.4028/www.scientific.net/amm.496-500.1369.
Testo completoAbstract (sommario):
Increasingly grim situation in recent years due to traffic, the new traffic conditions to the vehicle detector development and application of proposed new requirements, this paper introduces a new form of intelligent transportation vehicle detectors at the request of Vehicle Detector Research be brief, a brief analysis of a variety of vehicle detector works that feature discusses the trend of vehicle detector’s development
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Ambrožová, Iva, Kateřina Pachnerová Brabcová, Vyacheslav A. Shurshakov, Raisa V. Tolochek e Satoshi Kodaira. "ANGULAR DEPENDENCE OF TRACK-ETCH DETECTOR HARZLAS TD-1". Radiation Protection Dosimetry 186, n. 2-3 (7 novembre 2019): 219–23. http://dx.doi.org/10.1093/rpd/ncz206.
Testo completoAbstract (sommario):
Abstract Track-etched detectors are commonly used also for radiation monitoring onboard International Space Station. To be registered in track-etched detectors, the particle needs to meet several criteria—it must have linear energy transfer above the detection threshold and strike the detector’s surface under an angle higher than the so-called critical angle. Linear energy transfer is then estimated from calibration curve from the etch rate ratio V that is calculated from parameters of individual tracks appearing on the detector’s surface after chemical etching. It has been observed that V can depend on the incident angle and this dependence can vary for different detector materials, etching and evaluating conditions. To investigate angular dependence, detectors (Harzlas TD-1) were irradiated at HIMAC by several ions under angles from 0° to 90°. The correction accounting not only for critical angle but also for dependence of V on the incident angle is introduced and applied to spectra measured onboard International Space Station.
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Kushoro, Matteo Hakeem, Marica Rebai, Marco Tardocchi, Carmen Altana, Carlo Cazzaniga, Eliana De Marchi, Francesco La Via et al. "Detector Response to D-D Neutrons and Stability Measurements with 4H Silicon Carbide Detectors". Materials 14, n. 3 (26 gennaio 2021): 568. http://dx.doi.org/10.3390/ma14030568.
Testo completoAbstract (sommario):
The use of wide-band-gap solid-state neutron detectors is expanding in environments where a compact size and high radiation hardness are needed, such as spallation neutron sources and next-generation fusion machines. Silicon carbide is a very promising material for use as a neutron detector in these fields because of its high resistance to radiation, fast response time, stability and good energy resolution. In this paper, measurements were performed with neutrons from the ISIS spallation source with two different silicon carbide detectors together with stability measurements performed in a laboratory under alpha-particle irradiation for one week. Some consideration to the impact of the casing of the detector on the detector’s counting rate is given. In addition, the detector response to Deuterium-Deuterium (D-D) fusion neutrons is described by comparing neutron measurements at the Frascati Neutron Generator with a GEANT4 simulation. The good stability measurements and the assessment of the detector response function indicate that such a detector can be used as both a neutron counter and spectrometer for 2–4 MeV neutrons. Furthermore, the absence of polarization effects during neutron and alpha irradiation makes silicon carbide an interesting alternative to diamond detectors for fast neutron detection.
Tesi sul tema "Detectors"
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Carulla, Areste Maria del Mar. "Thin LG AD timing detectors for the ATLAS experiment". Doctoral thesis, Universitat Autònoma de Barcelona, 2019. http://hdl.handle.net/10803/667283.
Testo completoAbstract (sommario):
El gran col· lisionador de hadrons (LHC), el qual te un circumferencia de 27 quilometres, és l'accelerador de partícules més gran i potent del món. El LHC esta dissenyat per fer col· lisionar protons a 14 TeV en el seu centre de massa, aconseguint una lluminositat de 1024 cm-2 s-1, quan 2808 paquets amb 1011 protons cada un, circulen per l'accelerador. Els paquets estan espaiats per 25 ns, que corresponen a una freqüencia de col · lisió de 40 MHz en cada un dels quatre punts d'interacció.
Actualment, la principal prioritat de la estrategia europea per la física de partícules consisteix la explotació del LHC al seu maxim potencial. Es per aquest motiu que una actualització del LHC va ser planejada per tal d'assolir una nova fase d'intensa lluminositat del LHC (HL LHC). Aquesta nova fase del LHC (HL-LHC) necessitara una actualització tant de la maquina com dels detectors per tal que en 2030 es col · lecti deu vegades més dades que en el disseny inicial. El principals reptes que hauran de combatre els detectors per aquesta nova fase d'intensa lluminositat seran l'increment de l'ocupació, del pile-up, del ritme de dades i la resistencia a la radiació dels detectors. L'increment en l'ocupació sera mitigat utilitzant detectors amb major granularitat. Per altra banda detectors amb una resolució temporal de 30 ps seran utilitzats per recluir el pile-up.
L'objectiu de la present tesis es el disseny, desenvolupament i estudi de detectors de silici amb una elevada granularitat i amb una resolució temporal de 30 ps, els quals compleixen amb les especificacions necessaries per l'actualització del experiment ATLAS (A Toroidal LHC Apparatus). La col· laboració RD50, la qual investiga en l'estudi de detectors resistents a la radiació, ha proposat els detectors de allau amb baix guany (LGAD) com a detectors per a timing en les Endcap Timing Layers (ETL). En aquesta tesis tres estrategies diferents s'han dut a terme per tal de complir amb les especificacions de granularitat, resolució temporal i resistencia a la radiació de la ETL. La primera estrategia ha consistit en la reducción del gruix dels LGAD per tal de recluir el temps de col · lecció, el temps de pujada i la contribució del intrínsec Landau noise en la resolució temporal. La segona estrategia duta a terme ha estat la minimització de la capacitat per tal de recluir el soroll i la contribució del jitter en la resolució temporal, desenvolupant detectors LGAD pixelats i en strips. Finalment, l'última estrategia s'ha focalitzat en l'ús de diferents impureses per tal de recluir efectes de la radiació derivats de l'ús del bor coma impuresa dopant.
La estructura d'aquesta tesis es la següent: en el capítol 2 s'introdueixen el experiments d'altes energies on els detectors seran col · locats, les especificacions que han de complir els detectors en la nova fase d'intensa lluminositat, el funcionament dels detectors, la determinació de la resolució temporal, els efectes de la radiació en els detectors i un resum dels detectors utilitzats actualment per realitzar mesures de timing; en el capítol 3 es presenta les simulacions
tecnologiques i experimentals dels detectors dissenyats; en el capítol 4 es resumeix els processos tecnológics realitzats en la fabricació dels detectors; el capítol 5 presenta els resultats cxpcrirncntals dcls dispositius fabricats aba.ns i dcsprós de irradiar-los: el capítol 6 sintctitza la simulació, producció i resultats dels inverse Low Gain Avalanche Detectors (i-LGAD), i el capítol 7 presenta les conclusions i treball fntur dels detectors fabricats.The Large Hadron Collider (LHC) with its 27 kilometer in circumference is the world's largest and most powerful particle accelerator. The LHC was designed to collide protons at 14 TeV energy at the center-of-mass. The design luminosity is 1034 cm2 s-1, which is achieved with 2808 circulating bunches, each with - 1011 protons. Bunches are spaced by 25ns, corresponding to a collision rate of 40 MHz at each of the four interaction points. The main priority of the European Strategy for P article Physics is the exploitation of the full potential of the LHC. An upgrade of the LHC to the high-luminosity LHC (HL-LHC) was planned for this purpose. The HL-LHC will require an upgrade of the machine and detectors with a view to collecting ten times more data than in the initial design, by around 2030. The major challenges for the high-luminosity phase are the occupancy, pile-up, high data rates, and radiation tolerance of the detectors. The increase in occupancy will be mitigated using higher granularity. Fast timing detectors with time resolution in the range of 30 ps will be used to reduce pile-up. Fur thermore , precision timing will provide additional physics capabilities. The purpose of the present thesis is the design, development and study of silicon detectors with high granularity and 30 ps time resolution suitable for the upgrade of the A Toroidal LHC Apparatus (ATLAS) experiment in the HL-LHC phase. Low Gain Avalanche Detectors (LGAD) have been proposed by RD50 collaboration as timing detectors for the Endcap Timing Layer (ETL) of ATLAS experiment. Three different strategies have been studied in order to fulfil with the high granularity, time resolution and radiation hardness specifications of devices for the ET L. The first strategy has consisted in detectors thickness reduction to decrease its collection time, rise time and intrinsic Landau noise. The second strategy has been the minimization of the capacitance developing strips and pixels with gain. Finally, the last strategy has lied in the use of other dopants to reduce radiation effects as boron removal. The structure of the thesis is as follows: chapter 2 introduces the major issues in the LHC upgrade, the CERN experiments, the required specifications of particle detectors for the HL LHC phase, their working principles, the measurement of time resolution, the microscopic and macroscopic radiation effects, and the state of the art in timing detectors; chapter 3 presents the technological and electrical simulation of the designed devices after the calibration of the technological simulation with the process characterization; chapter 4 gives an outline of the different device processes; chapter 5 presents the obtained results of unirradiated and irradiated devices; chapter 6 condenses the simulation, production and results of inverse Low Gain Avalanche Detectors (i-LGAD), and chapter 7 reports the conclusions and future work of the measured devices.
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Fernández, Romero Luis. "Understanding the role of sensor diversity and redundancy to encode for chemical information in gas sensor arrays". Doctoral thesis, Universitat de Barcelona, 2016. http://hdl.handle.net/10803/395180.
Testo completoAbstract (sommario):
Electronic noses (e-noses) have been utilized during the past three decades as general purpose instruments for chemical sensing. These instruments are inspired by natural olfactory systems, where fine odour discrimination is performed without the necessity for highly specialized receptors. Instead, odour information is extracted in these systems using arrays of broadly tuned receptors organized in a convergent pathway. Such a sensing architecture allows combining the responses of the array of receptors, giving rise to particular representations of the different odour stimuli. The key advantage provided by this approach is that odour representation is more efficient and robust when the encoding is performed by the population of receptors than by any of its individual elements (hyper-acuity).
A population of receptors obtains its maximum performance in encoding odour stimulus features when it balances the benefits of sensory diversity and redundancy. By sensor diversity we understand the number of different receptor types responsible for enhancing the variability of the array response to a collection of odours. Likewise, by sensor redundancy we refer to the average number of receptor replicates on a population. The role of sensor redundancy accounts for the robustness to receptor damage and noise exhibited by the odour stimuli representation. This variety of odour receptor types along with its outstanding number of receptors is characteristic of natural olfactory systems. Though, traditional electronic noses tend to exhibit a limited number of sensor units with very much correlated responses to odour stimuli. Several strategies to enhance odour representation in gas sensor arrays are based on boosting sensor
diversity and redundancy. However, it has not been until recently that large arrays of cross-selective have become technologically available.
In this dissertation, we have developed one of these new generation arrays to investigate the advantages odour stimuli representation through population coding in artificial olfaction. In particular, we proposed to build a chemical sensing system based on an array of metal oxide (MOX) gas sensors, and endowed with a high a degree of sensor diversity and redundancy. We proposed the use this bio-inspired sensing architecture alongside statistical pattern recognition techniques to cope with some of the unsolved problems in machine olfaction (robustness to sensor damage, feature selection, and calibration transfer). The main contributions of this work were the following: We defined functionally sensor diversity and redundancy. These definitions were based on the clustering of the array features according to their similitude when responding to an odour dataset. We compared the different manner how natural and artificial olfactory systems encode for odour information using simple sensors models. We found that natural olfactory system principally encoded odour information in terms of odour quality, whereas that artificial ones in terms of odour quantity. Also, we studied the effect of sensor noise on odour concentration encoding. We proposed to decrease the contribution of the sensor noise by means of the redundant sensor feature averaging and sensor array optimization. These strategies were effective in case of independent sensor noise, but not for removing common sources of sensor noise. Similarly, we detected the importance of sensor failure dependency on the odour discrimination capabilities of a sensor. We found that this sensor fault distribution across had to be independent of the sensor type to prevent a dramatic worsening on the array’s predictive performance. In addition to this, we proposed an update of a feature selection method including a
dimensionality reduction stage so as to take into account the redundant information provided by the sensor array. Finally, we performed instrument standardization between temperature modulated sensor arrays to correct global shifts of temperature. A method to categorize the quality of the calibration transfer based on the bias-variance trade-off was presented.La nariz electrónica (e-nose) ha sido utilizada durante las últimas tres décadas como instrumento de propósito general para la detección química. Este instrumento está inspirado en los sistemas olfativos naturales, donde la discriminación de olores se realiza eficientemente sin la necesidad de receptores altamente especializados. La ventaja clave proporcionada por esta aproximación es que la representación de los olores es más eficiente y robusta cuando la codificación del olor es llevada a cabo por una población de receptores, pues esta supera la calidad de cualquiera realizada por sus elementos individuales. Una población de receptores obtiene su máximo rendimiento en la codificación de las características de un estímulo odorífero cuando se equilibran los beneficios de la diversidad y redundancia sensoriales. Lamentablemente, las narices electrónicas tradicionales tienden a exhibir un número limitado de sensores con respuestas muy correlacionas ante diferentes conjuntos de estímulos odoríferos. Sin embargo, no ha sido hasta hace relativamente poco que la creación grandes matrices de sensores con selectividades cruzadas ha sido tecnológicamente posibles. El objetivo de esta tesis es el desarrollo de una de estas matrices de nueva generación para investigar las ventajas de la representación de los estímulos odoríferos través de una codificación poblacional soportada por la diversidad y redundancia sensoriales. En particular, hemos construido un sistema de detección química basado en una matriz de sensores de gas de óxido metálico (MOX), y dotada de un alto grado de diversidad y redundancia sensoriales. Hemos utilizado esta arquitectura de detección química bioinspirada junto técnicas de reconocimiento de patrones estadísticas para hacer frente a algunos de los problemas sin resolver en olfacción artificial, a saber, la robustez al fallo de sensores, la selección de características, y la transferencia de calibración entre diferentes narices electrónicas.
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Morais, Rogério Miranda. "Caracterização de dispositivos a base de Pani e Pedot: PSS impressos por impressora jato de tinta visando aplicações como sensores /". Presidente Prudente, 2015. http://hdl.handle.net/11449/154691.
Testo completoAbstract (sommario):
Orientador: Neri AlvesBanca: Dante Luis Chanaglia
Banca: Felippe Jose Pavinatto
O Programa de Pós Graduação em Ciência e Tecnologia de Materiais, PosMat, tem caráter institucional e integra as atividades de pesquisa em materiais de diversos campi
Resumo: Nesta dissertação é apresentada a produção e caracterização de sensores de umidade e amônia totalmente impressos, usando uma impressora jato de tinta comercial. "Tintas" de PANI e PEDOT:PSS foram preparadas e impressas usando uma impressora HP Deskjet D2460. Filmes do polímero condutor PEDOT:PSS foi impresso sobre substratos de papeis e de plásticos e suas propriedades morfológicas e elétricas foram avaliadas em função da densidade superficial de material impresso e da rugosidade dos substratos a fim de obter filmes impressos correntes elétricas suficientes para atuação como eletrodos. Filmes de PANI, com diferentes número de impressões, foram impressos entre os eletrodos de PEDOT:PSS e caracterizações elétricas para o dispositivo PANI/PEDOT/papel antes e após expor ao vapor de HCI, processo no qual promove a dopagem do dispositivo, usando medidas DC e de espectroscopia de impedância (EI). Mostra-se que os resultados, para o sistema impresso PANI/PEDOT/papel, podem ser modelados por um circuito equivalente contendo um resistor R em paralelo com um capacitador C, ambos em série com outro resistor r. As variações de cada parâmetro foram avaliadas em função da exposição a direrentes percentuais de umidade relativa do ar (%UR) e concentrações de amônia (% e ppm). O resistor r, contido no circuito equivalente demonstrou maior resposta e sensibilidade à exposição tanto de umidade quanto de gás amônia mostrando a viabilidade de aplicação deste sistema impresso como sensor. Uma maior sensibilidade para o sistema PANI/PEDOT/papel (sensores de papel) pode ser obtida realizando um tratamento térmico promovendo a evaporação do excesso de HCI no sistema. Para monitoramentos em baixas concentrações de NH3 dispositivos na configuração PANI/PEDOT/PET (sensores plásticos) apresentaram tanto resposta sensitiva quanto tempo de resposta melhores quando comparados aos sensores de papel tratados termicamente
Abstract: This work presents the production and characterization of humidity sensors and fully printed ammonia, using an inkjet printer commercial. "Inks" of PANIN and PEDOT:PSS were prepared and printed using an HP Deskjet D2460 printer. Films of the conducting polymer PEDOT:PSS was printed on paper and plastic substrates and their morphological and electrical properties were evaluated in function of the surface density of printed material and roughness of the substrate in order to obtain printed films with sufficient electrical current to operate as electrodes. Films of PANI, with different number of prints, were printed between the electrodes of PEDOT:PSS AND electrical characterization for the device PANI/PEDOT/paper, before and after exposed to steam HCI, process in which promoting the device doping, were realized using measures DC and impedance spectroscopy (EI). It shows that the results for the printing sytem PANI/PEDOT/paper can be modeled by an equivalent circuit comprising a resistor R in parallel with a capacitor C, both in series with another resistor r. Variations of each parameter were evaluated in function of exposure to different humidity percentage of the air (%RH) and ammonia concentrations (ppm and %). The resistor r contained in the equivalent circuit shown greater response and sensitivity to exposure as much moisture as gas ammonia showing the application feasibility of this system as printed sensor. An increased sensibility to the sytem PANI/PEDOT/paper (paper sensors) can be obtained by performing a heat treatment to promote evaporation of the excess of HCI in the system. For monitoring low concentrations of NH3, devices in PANI configuration PANI/PEDOT/PET (plastic sensors) demonstrated so much an better sensitive response low much an better time response compared to paper sensors treated thermally
Mestre
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Morais, Rogério Miranda [UNESP]. "Caracterização de dispositivos a base de Pani e Pedot: PSS impressos por impressora jato de tinta visando aplicações como sensores". Universidade Estadual Paulista (UNESP), 2015. http://hdl.handle.net/11449/154691.
Testo completoAbstract (sommario):
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000864897.pdf: 2555589 bytes, checksum: c920340f90ea5680312e850c433369e4 (MD5)Nesta dissertação é apresentada a produção e caracterização de sensores de umidade e amônia totalmente impressos, usando uma impressora jato de tinta comercial. Tintas de PANI e PEDOT:PSS foram preparadas e impressas usando uma impressora HP Deskjet D2460. Filmes do polímero condutor PEDOT:PSS foi impresso sobre substratos de papeis e de plásticos e suas propriedades morfológicas e elétricas foram avaliadas em função da densidade superficial de material impresso e da rugosidade dos substratos a fim de obter filmes impressos correntes elétricas suficientes para atuação como eletrodos. Filmes de PANI, com diferentes número de impressões, foram impressos entre os eletrodos de PEDOT:PSS e caracterizações elétricas para o dispositivo PANI/PEDOT/papel antes e após expor ao vapor de HCI, processo no qual promove a dopagem do dispositivo, usando medidas DC e de espectroscopia de impedância (EI). Mostra-se que os resultados, para o sistema impresso PANI/PEDOT/papel, podem ser modelados por um circuito equivalente contendo um resistor R em paralelo com um capacitador C, ambos em série com outro resistor r. As variações de cada parâmetro foram avaliadas em função da exposição a direrentes percentuais de umidade relativa do ar (%UR) e concentrações de amônia (% e ppm). O resistor r, contido no circuito equivalente demonstrou maior resposta e sensibilidade à exposição tanto de umidade quanto de gás amônia mostrando a viabilidade de aplicação deste sistema impresso como sensor. Uma maior sensibilidade para o sistema PANI/PEDOT/papel (sensores de papel) pode ser obtida realizando um tratamento térmico promovendo a evaporação do excesso de HCI no sistema. Para monitoramentos em baixas concentrações de NH3 dispositivos na configuração PANI/PEDOT/PET (sensores plásticos) apresentaram tanto resposta sensitiva quanto tempo de resposta melhores quando comparados aos sensores de papel tratados termicamente
This work presents the production and characterization of humidity sensors and fully printed ammonia, using an inkjet printer commercial. Inks of PANIN and PEDOT:PSS were prepared and printed using an HP Deskjet D2460 printer. Films of the conducting polymer PEDOT:PSS was printed on paper and plastic substrates and their morphological and electrical properties were evaluated in function of the surface density of printed material and roughness of the substrate in order to obtain printed films with sufficient electrical current to operate as electrodes. Films of PANI, with different number of prints, were printed between the electrodes of PEDOT:PSS AND electrical characterization for the device PANI/PEDOT/paper, before and after exposed to steam HCI, process in which promoting the device doping, were realized using measures DC and impedance spectroscopy (EI). It shows that the results for the printing sytem PANI/PEDOT/paper can be modeled by an equivalent circuit comprising a resistor R in parallel with a capacitor C, both in series with another resistor r. Variations of each parameter were evaluated in function of exposure to different humidity percentage of the air (%RH) and ammonia concentrations (ppm and %). The resistor r contained in the equivalent circuit shown greater response and sensitivity to exposure as much moisture as gas ammonia showing the application feasibility of this system as printed sensor. An increased sensibility to the sytem PANI/PEDOT/paper (paper sensors) can be obtained by performing a heat treatment to promote evaporation of the excess of HCI in the system. For monitoring low concentrations of NH3, devices in PANI configuration PANI/PEDOT/PET (plastic sensors) demonstrated so much an better sensitive response low much an better time response compared to paper sensors treated thermally
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Passmore, Mark Steven. "Pixel detectors". Thesis, University of Glasgow, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.394948.
Testo completo
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Figueira, Eduardo Carneiro [UNESP]. "Estudo e desenvolvimento de sensores biomiméticos baseados em materiais carbonáceos modificados com ftalocianinacobalto (II) para detecção amperométrica de metribuzin". Universidade Estadual Paulista (UNESP), 2012. http://hdl.handle.net/11449/97832.
Testo completoAbstract (sommario):
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figueira_ec_me_araiq.pdf: 587676 bytes, checksum: 98efacb031457690129ecec80299f3ac (MD5)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
O presente trabalho está baseado na construção de sensores biomiméticos para monitoramento sensível e seletivo do agrotóxico metribuzin (MTZ). Para isto, eletrodos à base de pasta de carbono e nanotubos de carbono foram modificados com diversos complexos potenciais catalisadores biomiméticos das enzimas P450, que são enzimas que catalisam um grande número de reações incluindo os agrotóxicos. O complexo que apresentou perfil biomimético e melhores resultados na determinação amperométrica do metribuzin foi à ftalocianinacobalto (II) [CoPc]. Quando construídos sensores à base de pasta de carbono modificada com CoPc, os melhores resultados foram obtidos usando 15% (m/m) de complexo na preparação da pasta e realizando as medidas em tampão Britton-Robinson 0,08 mol L-1 (pH 2,0), aplicando potencial de -690 mV vs Ag|AgCl. Sob estas condições obteve-se uma faixa linear de resposta de 2,4 x 10-5 a 2,0 x 10-4 mol L-1, com uma boa sensibilidade e LOD e LOQ de 4,3 x 10-6 e 1,4 x 10-5 mol L-1, respectivamente. Estudos relacionados a elucidar a biomimeticidade do sensor, incluíram avaliação da influência da velocidade de varredura empregando voltametria cíclica, exploração do perfil hiperbólico da resposta do sensor e estudo de interferentes e de seletividade. A seguir, foi avaliada a influencia de nanotubos de carbono de paredes múltiplas (MWCNT) na preparação da pasta no intuito de tentar aumentar a detectabilidade do sensor modificado com ftalocianinacobalto (II). Entretanto, os resultados obtidos não foram àqueles esperados, devido principalmente, à grande quantidade de material aglutinante (Nujol® que é isolante) necessário para a obtenção da pasta. Assim, a seguir, foi realizada a avaliação de eletrodos impressos à base de grafite, contendo MWCNT a 0,3% e CoPc a 5%, 10% e 15% (m/m). Sob as condições de...
This work is based on the construction of biomimetic sensors for monitoring sensitive and selective pesticide metribuzin (MTZ). For this, the base electrodes of carbon paste and carbon nanotubes have been modified with various complex catalysts potential biomimetic of P450 enzymes, which are enzymes that catalyze a large number of reactions including pesticides. The complex profile that showed better results in biomimetic and amperometric determination of metribuzin was the ftalocianinacobalto (II) [CoPc]. When constructed sensors based on a modified carbon paste CoPc with the best results were obtained using 15% (m/ m) complex in the preparation of the folder and making the measurements in Britton-Robinson buffer 0,08 mol L-1 (pH 2,0), by applying potential to -690 mV vs Ag | AgCl. Under these conditions gave a linear response range of 2.4 x 10-5 to 2.0 x 10-4 mol L-1, and with good sensitivity and LOQ and LOD of 4,3 x 10-6 and 1 , 4 x 10-5 mol L-1, respectively. Related studies to elucidate the biomimeticidade sensor, included evaluation of the influence of scan rate using cyclic voltammetry, exploitation of hyperbolic profile of the sensor response and the study of interferences and selectivity. Next, we evaluated the influence of carbon nanotubes multi-walled (MWCNT) in the preparation of the folder in order to try to increase the detectability of the sensor modified with ftalocianinacobalto (II). However, the results were not those expected, mainly due to the large amount of binder material (Nujol ® which is an insulator) necessary for obtaining the paste. Thus, the following evaluation was made electrodes printed based on graphite containing MWCNT CoPc 0,3% and 5%, 10% and 15% (m / m). Under the above conditions optimized for the analysis carbon paste, the printed electrode that provided the best... (Complete abstract click electronic access below)
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Santos, André Luiz dos [UNESP]. "Desenvolvimento de sistem biomimético para análise de 3,5,6-Tricloro-2-piridinol, o principal metabólito do clorpirifós". Universidade Estadual Paulista (UNESP), 2012. http://hdl.handle.net/11449/97833.
Testo completoAbstract (sommario):
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santos_al_me_araiq.pdf: 1374698 bytes, checksum: 4000b6c44028dbd65db8795f30a87ff5 (MD5)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
O presente trabalho está baseado no desenvolvimento de um sistema biomimético para monitoramento sensível e seletivo do metabólito TCP (3,5,6-tricloro-2-piridinol), proveniente do agrotóxico clorpitifós, o qual é mais solúvel que o próprio agrotóxico e cuja ocorrência em águas subterrâneas e superficiais é mais provável e perigosa. Foi construído um sensor biomimético com detecção voltamétrica por onda quadrada, os eletrodos, foram confeccionados à base de pasta de carbono modificada com o complexo cloro-5,10,15,20-tetraquis(pentafluorofenil)-21H,23H-porfirina ferro (III), o qual apresenta uma estrutura química semelhante à do sítio ativo da enzima P450. O sensor construído apresentou as melhores respostas em tampão fosfato 0,20 mol L-1 e pH 6,0, usando a voltametria de onda quadrada a 50 Hz, 150 mV de amplitude e 1,5 mV de E. Com os parâmetros otimizados o sensor apresentou limites de detecção e de quantificação de 1,9 e 5,2 μmol L-1, respectivamente. Estudos realizados para averiguar a biomimeticidade do sensor, incluíram: velocidade de varredura por voltametria cíclica, exploração do perfil hiperbólico da resposta no sensor e avaliação da seletividade. O sensor foi satisfatoriamente usado na análise em diversos tipos de amostras de interesse ambiental. Foram feitos testes de recuperação e nas amostras de solo, águas superficiais e subterrâneas obtendo recuperação de 91%, 107% e 96% respectivamente, mostrando que o sensor pode ser usado como método alternativo para quantificação de TCP em diferentes matrizes. O sensor também foi empregado no monitoramento da eficiência de polímeros de impressão molecular (MIP) para TCP. Buscando obter o polímero biomimético mais eficiente para o analito, foram usadas ferramentas computacionais que permitiram escolher o melhor monômero (acrilonitrila)...
This work is based on developing a biomimetic system for sensitive and selective monitoring of the TCP (3,5,6-trichloro-2-pyridinol), the principal metabolite of the pesticide chlorpyrifos, which is more soluble than the pesticide and whose occurrence in groundwater and surface water is more likely and dangerous. For this, a biomimetic sensor was constructed and the square wave voltammetric was used for measurements. The electrodes were fabricated using carbon paste modified with the complex chloro-5,10,15,20-tetrakis-(pentafluorophenyl)-21H,23H-porphyrin iron(III), which has a chemical structure similar to the active site of the enzyme P450. The sensor presented the best responses in phosphate buffer 0.20 mol L-1 and pH 6.0, using the square wave voltammetry with 50 Hz, amplitude of potential of 150 mV and ΔE of 1.5 mV. With the optimized parameters the sensor showed limits of detection and quantification of 1.9 and 5.2 μmol L-1, respectively. Studies conducted to investigate the mimicking of the sensor, included evaluation of the influence on scan rate in the cyclic voltammetry, the verification of the hyperbolic profile of the sensor response and evaluation of selectivity. The sensor has been satisfactorily applied in the analysis of different samples of environmental interest. Recovery experiments in samples of soil, surface water, and groundwater showed values of 91%, 107% and 96% respectively, showing that the sensor can be used as an alternative method for the quantification of TCP in different matrices. The sensor was also used to monitor the efficiency of molecularly imprinted polymers (MIP) for TCP. In order to obtain the most efficient biomimetic polymer to this analyte were used computational tools that allowed select the best monomer (acrylonitrile). In order to verify the results obtained by the theoretical... (Complete abstract click electronic access below)
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Figueira, Eduardo Carneiro. "Estudo e desenvolvimento de sensores biomiméticos baseados em materiais carbonáceos modificados com ftalocianinacobalto (II) para detecção amperométrica de metribuzin /". Araraquara, 2012. http://hdl.handle.net/11449/97832.
Testo completoAbstract (sommario):
Orientador: Maria Del Pilar Taboada SotomayorBanca: Iara Lucia Tescarollo Dias
Banca: Emerson Schwingel Ribeiro
Resumo: O presente trabalho está baseado na construção de sensores biomiméticos para monitoramento sensível e seletivo do agrotóxico metribuzin (MTZ). Para isto, eletrodos à base de pasta de carbono e nanotubos de carbono foram modificados com diversos complexos potenciais catalisadores biomiméticos das enzimas P450, que são enzimas que catalisam um grande número de reações incluindo os agrotóxicos. O complexo que apresentou perfil biomimético e melhores resultados na determinação amperométrica do metribuzin foi à ftalocianinacobalto (II) [CoPc]. Quando construídos sensores à base de pasta de carbono modificada com CoPc, os melhores resultados foram obtidos usando 15% (m/m) de complexo na preparação da pasta e realizando as medidas em tampão Britton-Robinson 0,08 mol L-1 (pH 2,0), aplicando potencial de -690 mV vs Ag|AgCl. Sob estas condições obteve-se uma faixa linear de resposta de 2,4 x 10-5 a 2,0 x 10-4 mol L-1, com uma boa sensibilidade e LOD e LOQ de 4,3 x 10-6 e 1,4 x 10-5 mol L-1, respectivamente. Estudos relacionados a elucidar a biomimeticidade do sensor, incluíram avaliação da influência da velocidade de varredura empregando voltametria cíclica, exploração do perfil hiperbólico da resposta do sensor e estudo de interferentes e de seletividade. A seguir, foi avaliada a influencia de nanotubos de carbono de paredes múltiplas (MWCNT) na preparação da pasta no intuito de tentar aumentar a detectabilidade do sensor modificado com ftalocianinacobalto (II). Entretanto, os resultados obtidos não foram àqueles esperados, devido principalmente, à grande quantidade de material aglutinante (Nujol® que é isolante) necessário para a obtenção da pasta. Assim, a seguir, foi realizada a avaliação de eletrodos impressos à base de grafite, contendo MWCNT a 0,3% e CoPc a 5%, 10% e 15% (m/m). Sob as condições de... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: This work is based on the construction of biomimetic sensors for monitoring sensitive and selective pesticide metribuzin (MTZ). For this, the base electrodes of carbon paste and carbon nanotubes have been modified with various complex catalysts potential biomimetic of P450 enzymes, which are enzymes that catalyze a large number of reactions including pesticides. The complex profile that showed better results in biomimetic and amperometric determination of metribuzin was the ftalocianinacobalto (II) [CoPc]. When constructed sensors based on a modified carbon paste CoPc with the best results were obtained using 15% (m/ m) complex in the preparation of the folder and making the measurements in Britton-Robinson buffer 0,08 mol L-1 (pH 2,0), by applying potential to -690 mV vs Ag | AgCl. Under these conditions gave a linear response range of 2.4 x 10-5 to 2.0 x 10-4 mol L-1, and with good sensitivity and LOQ and LOD of 4,3 x 10-6 and 1 , 4 x 10-5 mol L-1, respectively. Related studies to elucidate the biomimeticidade sensor, included evaluation of the influence of scan rate using cyclic voltammetry, exploitation of hyperbolic profile of the sensor response and the study of interferences and selectivity. Next, we evaluated the influence of carbon nanotubes multi-walled (MWCNT) in the preparation of the folder in order to try to increase the detectability of the sensor modified with ftalocianinacobalto (II). However, the results were not those expected, mainly due to the large amount of binder material (Nujol ® which is an insulator) necessary for obtaining the paste. Thus, the following evaluation was made electrodes printed based on graphite containing MWCNT CoPc 0,3% and 5%, 10% and 15% (m / m). Under the above conditions optimized for the analysis carbon paste, the printed electrode that provided the best... (Complete abstract click electronic access below)
Mestre
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Santos, André Luiz dos. "Desenvolvimento de sistem biomimético para análise de 3,5,6-Tricloro-2-piridinol, o principal metabólito do clorpirifós /". Araraquara, 2012. http://hdl.handle.net/11449/97833.
Testo completoAbstract (sommario):
Orientador: Maria Del Pilar Taboada SotomayorBanca: Marcos Roberto de Vasconcelos Lanza
Banca: Rosa Amália Fireman Dutra
Resumo: O presente trabalho está baseado no desenvolvimento de um sistema biomimético para monitoramento sensível e seletivo do metabólito TCP (3,5,6-tricloro-2-piridinol), proveniente do agrotóxico clorpitifós, o qual é mais solúvel que o próprio agrotóxico e cuja ocorrência em águas subterrâneas e superficiais é mais provável e perigosa. Foi construído um sensor biomimético com detecção voltamétrica por onda quadrada, os eletrodos, foram confeccionados à base de pasta de carbono modificada com o complexo cloro-5,10,15,20-tetraquis(pentafluorofenil)-21H,23H-porfirina ferro (III), o qual apresenta uma estrutura química semelhante à do sítio ativo da enzima P450. O sensor construído apresentou as melhores respostas em tampão fosfato 0,20 mol L-1 e pH 6,0, usando a voltametria de onda quadrada a 50 Hz, 150 mV de amplitude e 1,5 mV de E. Com os parâmetros otimizados o sensor apresentou limites de detecção e de quantificação de 1,9 e 5,2 μmol L-1, respectivamente. Estudos realizados para averiguar a biomimeticidade do sensor, incluíram: velocidade de varredura por voltametria cíclica, exploração do perfil hiperbólico da resposta no sensor e avaliação da seletividade. O sensor foi satisfatoriamente usado na análise em diversos tipos de amostras de interesse ambiental. Foram feitos testes de recuperação e nas amostras de solo, águas superficiais e subterrâneas obtendo recuperação de 91%, 107% e 96% respectivamente, mostrando que o sensor pode ser usado como método alternativo para quantificação de TCP em diferentes matrizes. O sensor também foi empregado no monitoramento da eficiência de polímeros de impressão molecular (MIP) para TCP. Buscando obter o polímero biomimético mais eficiente para o analito, foram usadas ferramentas computacionais que permitiram escolher o melhor monômero (acrilonitrila)... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: This work is based on developing a biomimetic system for sensitive and selective monitoring of the TCP (3,5,6-trichloro-2-pyridinol), the principal metabolite of the pesticide chlorpyrifos, which is more soluble than the pesticide and whose occurrence in groundwater and surface water is more likely and dangerous. For this, a biomimetic sensor was constructed and the square wave voltammetric was used for measurements. The electrodes were fabricated using carbon paste modified with the complex chloro-5,10,15,20-tetrakis-(pentafluorophenyl)-21H,23H-porphyrin iron(III), which has a chemical structure similar to the active site of the enzyme P450. The sensor presented the best responses in phosphate buffer 0.20 mol L-1 and pH 6.0, using the square wave voltammetry with 50 Hz, amplitude of potential of 150 mV and ΔE of 1.5 mV. With the optimized parameters the sensor showed limits of detection and quantification of 1.9 and 5.2 μmol L-1, respectively. Studies conducted to investigate the mimicking of the sensor, included evaluation of the influence on scan rate in the cyclic voltammetry, the verification of the hyperbolic profile of the sensor response and evaluation of selectivity. The sensor has been satisfactorily applied in the analysis of different samples of environmental interest. Recovery experiments in samples of soil, surface water, and groundwater showed values of 91%, 107% and 96% respectively, showing that the sensor can be used as an alternative method for the quantification of TCP in different matrices. The sensor was also used to monitor the efficiency of molecularly imprinted polymers (MIP) for TCP. In order to obtain the most efficient biomimetic polymer to this analyte were used computational tools that allowed select the best monomer (acrylonitrile). In order to verify the results obtained by the theoretical... (Complete abstract click electronic access below)
Mestre
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Bergamini, Márcio Fernando. "Eletrodos impressos modificados com poli-histidina aplicados na construção de sensores eletroquímicos para crômio(VI) e fármacos /". Araraquara, 2007. http://hdl.handle.net/11449/105754.
Testo completoAbstract (sommario):
Orientador: Maria Valnice Boldrin ZanoniBanca: Hideko Yamanaka
Banca: Orlando Fatibello Filho
Banca: Mauro Bertotti
Banca: Auro Atsushi Tanaka
Resumo: O presente trabalho investiga a aplicação de eletrodos impressos, de carbono (SPCE) e ouro (SPGE), na determinação de espécies de interesse farmacêutico, tais como, aurotiomalato, L-dopa e procaína, utilizando sistemas convencionais, com fluxo de solução e análise por injeção em fluxo, respectivamente. Após a otimização de todos os parâmetros voltamétricos e inerentes da técnica construí-se curvas analíticas para cada composto farmacêutico com respostas lineares entre concentrações de 1,4 x 10-6 a 1,5 x 10-4 mol L-1, 1,5 x 10-6 a 6,6 x 10-4 mol L-1 e 1,0 x 10-5 a 1,0 x 10-4 mol L-1 para o aurotiomalato, a L-dopa e a procaína, respectivamente. O método foi aplicado na determinação dessas espécies em formulações farmacêuticas. A construção e caracterização voltamétrica de. eletrodos de carbono impresso (SPCE) por filmes de poli-histidina (PH) foi também investigada com intuito de ampliar o nível de sensibilidade e seletividade dos métodos voltamétricos. Para isso, foram testados três diferentes procedimentos de para a construção dos eletrodos modificados: a adição direta de uma solução do polímero (SPCE/PH), a utilização de uma reação cruzada entre a poli-histidina e o glutaraldeído (SPCE/Glu-PH) e a eletropolimerização a partir do monômero histidina (SPCE/EPH). O comportamento voltamétrico dos eletrodos modificados mostrou-se fortemente dependente do procedimento de preparação dos filmes. Eletrodos SPCE/PH e SPCE/Glu-PH apresentaram uma alta eficiência na pré-concentração de ânions, como o ferricianeto. Não sendo observado nenhum efeito eletrocatalítico para a oxidação de ácido ascórbico com esses eletrodos. Já para o SPCE/EPH foi observado um baixo desempenho na pré-concentração de ânions, mas um pronunciado efeito eletrocatalítico para a oxidação de ácido ascórbico. A aderência e estabilidade das respostas obtidas...(Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The present work investigated the application of screen-printed carbon (SPCE) and screen-printed gold electrodes (SPGE) in the determination of species of pharmaceutical interest, such as, aurothiomalate, L-dopa and procaine. The performance of all electrodes was tested in a conventional electrochemical system, and also in two electrochemical cells using amperometric detection. The first one was constructed to operate on hydrodynamic system and the second one to work on flow injection analysis (FIA) system. Analytical curves were obtained for all systems with linear relationship from peak current vs concentration from 1.4 x 10-6 to 1.5 x 10-4 mol L-1 for aurothiomalate; 1.5 x 10-6 to 6.6 x 10-4 mol L-1 for L-dopa and 1.0 x 10-5 to 1.0 x 10-4 mol L-1 for procaine, respectively. The method was tested in pharmaceutical compounds with good recovery. Screen-printed carbon electrodes (SPCE) can be easily modified with poly-histidine (PH) films using three different procedures: by direct addition of a poly-histidine solution on the electrode surface (SPCE/PH), using a cross-link reaction between poly-histidine and glutaraldehyde (SPCE/Glu-PH) and by electropolymerization of the histidine monomer (SPCE/EPH). The voltammetric behavior of the three modified electrodes was evaluated using potassium hexacyanoferrate(III) and ascorbic acid as model compounds. All modified electrode from stable films, but SPCE coated by deposition of PH and Glu-PH presented higher efficiency for pre concentration anions, while SPCE coated by electropolymerization of the monomer (EPH) presented pronounced electrocatalytic effect in the ascorbic acid oxidation. The resulting PH films presented good adherence and high stabilities and they were applied in the voltammetric analysis of isoniazide, pyrazinamide, aurothiomalate and chromium (VI). The best experimental condition for isoniazide and pyrazinamide...(Complete abstract click electronic access below)
Doutor
Libri sul tema "Detectors"
1
United States. Federal Highway Administration. e Diaz, Seckinger & Associates., a cura di. Traffic detector handbook: Field manual for inductive loop detectors, magnetometers, magnetic detectors. [Washington, D.C.]: U.S. Dept. of Transportation, Federal Highway Administration, 1985.
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United States. Federal Highway Administration. e Diaz, Seckinger & Associates., a cura di. Traffic detector handbook: Field manual for inductive loop detectors, magnetometers, magnetic detectors. [Washington, D.C.]: U.S. Dept. of Transportation, Federal Highway Administration, 1985.
Cerca il testo completo
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Larason, Thomas C. Spectroradiometric detector measurements: Part 1-ultraviolet detectors and part II-visible to near-infrared detectors. Gaithersburg, MD: U.S. Dept. of Commerce, Technology Administration, National Institute of Standards and Technology, 1998.
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Rossi, Leonardo, Peter Fischer, Tilman Rohe e Norbert Wermes. Pixel Detectors. Berlin, Heidelberg: Springer Berlin Heidelberg, 2006. http://dx.doi.org/10.1007/3-540-28333-1.
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Villa, Francesco, a cura di. Vertex Detectors. Boston, MA: Springer US, 1988. http://dx.doi.org/10.1007/978-1-4899-2545-9.
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Grupen, Claus. Particle detectors. Cambridge [England]: Cambridge University Press, 1996.
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Rogalski, Antoni. Infrared detectors. 2a ed. Boca Raton: Taylor & Francis, 2011.
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Rogalski, Antoni. Infrared detectors. Amsterdam: Gordon and Breach, 2000.
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Rogalski, Antoni. Infrared detectors. 2a ed. Boca Raton: Taylor & Francis, 2011.
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Grupen, Claus. Particle Detectors. 2a ed. Cambridge: Cambridge University Press, 2008.
Cerca il testo completoCapitoli di libri sul tema "Detectors"
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Frühwirth, Rudolf, e Are Strandlie. "Tracking Detectors". In Pattern Recognition, Tracking and Vertex Reconstruction in Particle Detectors, 3–21. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-65771-0_1.
Testo completoAbstract (sommario):
AbstractThe chapter gives an overview of particle detectors, with the emphasis on tracking detectors. The working principles and the calibration of gaseous, semiconductor, and fiber detectors are explained, followed by a brief review of detector alignment. As an illustration, the tracking systems of the four experiments at the LHC and two non-LHC experiments, Belle II and CBM, are presented.
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Da Silva Gameiro, Henrique. "LLM Detectors". In Large Language Models in Cybersecurity, 197–204. Cham: Springer Nature Switzerland, 2024. http://dx.doi.org/10.1007/978-3-031-54827-7_22.
Testo completoAbstract (sommario):
AbstractLLM detectors aim at detecting text generated by an LLM. They can be categorized into two main types: specific detectors and general detectors. Specific detectors target a particular type of language or context, such as hate speech or spam. In contrast, general detectors aim to identify a broad range of problematic languages, such as misinformation or propaganda. They typically rely on supervised learning, using large labeled datasets to train the models to recognize patterns in the language. General-purpose detectors have shown bad results, but specific-purpose detectors have shown more promising results. This has to be nuanced due to the broad range of effective attacks, especially the paraphrasing attacks, to which all defense techniques are somewhat vulnerable. There are also many other challenges for developing detectors such as the growing numbers of different LLMs (open source or not) being developed and an effective detector that works with many human languages besides English. Mitigation techniques include storing user conversations with an LLM and watermarking (especially cryptographic).
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Kunze, Hans-Joachim. "Detectors". In Introduction to Plasma Spectroscopy, 53–74. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-02233-3_4.
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Léna, Pierre. "Detectors". In Astronomy and Astrophysics Library, 146–208. Berlin, Heidelberg: Springer Berlin Heidelberg, 1988. http://dx.doi.org/10.1007/978-3-662-02554-3_5.
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Sahni, Subal, e Gianlorenzo Masini. "Detectors". In Photonics and Electronics with Germanium, 165–89. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2015. http://dx.doi.org/10.1002/9783527650200.ch8.
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Bethge, Klaus, Gerhard Kraft, Peter Kreisler e Gertrud Walter. "Detectors". In Biological and Medical Physics, Biomedical Engineering, 53–72. Berlin, Heidelberg: Springer Berlin Heidelberg, 2004. http://dx.doi.org/10.1007/978-3-662-08608-7_4.
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Léna, Pierre, Daniel Rouan, François Lebrun, François Mignard e Didier Pelat. "Detectors". In Astronomy and Astrophysics Library, 323–440. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-21815-6_7.
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Bründermann, Erik, Heinz-Wilhelm Hübers e Maurice F. Kimmitt. "Detectors". In Springer Series in Optical Sciences, 169–245. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-02592-1_5.
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Dolan, John W., e Lloyd R. Snyder. "Detectors". In Troubleshooting LC Systems, 327–66. Totowa, NJ: Humana Press, 1989. http://dx.doi.org/10.1007/978-1-59259-640-9_12.
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Andersson, Jan T. "Detectors". In Practical Gas Chromatography, 205–48. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-54640-2_6.
Testo completoAtti di convegni sul tema "Detectors"
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Tucker, Walter, e John L. Barrett. "Heterodyne Efficiency of Quadrant Detectors". In Coherent Laser Radar. Washington, D.C.: Optica Publishing Group, 1987. http://dx.doi.org/10.1364/clr.1987.mb3.
Testo completoAbstract (sommario):
Considerable work has been done on heterodyne efficiency of optical detectors1-6. Properties considered have been beam spot size, phase front alignment and detector uniformity. Efficiencies have been evaluated using combinations of Planar, Airy, and Gaussian signal and local oscillator fields. Previous work has dealt with circular, single detectors.
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Steinlechner, Jessica, Peter G. Murray, Massimo Granata e Riccardo Bassiri. "Coatings for Gravitational Wave Detectors". In Optical Interference Coatings. Washington, D.C.: Optica Publishing Group, 2022. http://dx.doi.org/10.1364/oic.2022.wa.4.
Testo completoAbstract (sommario):
This article gives an overview of optical coatings for gravitational-wave detectors, presenting considerations about candidate coating materials to further improve the sensitivity of the Advanced LIGO and Virgo detectors and of detector generations beyond.
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Jackson, D. J., e D. L. Persechini. "Monolithically integrable lateral PIN detectors". In Integrated and Guided Wave Optics. Washington, D.C.: Optica Publishing Group, 1986. http://dx.doi.org/10.1364/igwo.1986.wcc5.
Testo completoAbstract (sommario):
Monolithically integrable detectors are defined as detectors whose fabrication is completely compatible with the design rules used in the standard integrated circuit fabrication. An interdigitated electrode geometry permits both the ready integration of these detectors into electronic IC topologies and the use of a large detection area in conjunction with a low device capacitance. The large detector area improves the signal strength available for amplification, while the low capacitance extends the high-frequency bandwidth. To date, most interdigitated detectors reported in the literature are of the Schottky or photoconductive variety.1 Unfortunately, the low channel resistance between the interdigitated fingers produces a large Johnson noise contribution in these devices which increases linearly with the frequency.2 In comparison, the intrinsically high shunt resistance of a PIN diode enhances the SNR by limiting the Johnson noise contribution, thereby optimizing the detector dynamic range.
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Rogers, D. L. "Interdigitated Metal–Semiconductor–Metal Detectors". In Picosecond Electronics and Optoelectronics. Washington, D.C.: Optica Publishing Group, 1989. http://dx.doi.org/10.1364/peo.1989.osda184.
Testo completoAbstract (sommario):
The Interdigitated-Metal-Semiconductor-Metal (IMSM) detector has recently become one of the more popular detectors for optoelectronic integration. The factors affecting the performance of this type of detector are reviewed particularly in the context of low noise amplification circuitry.
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Zhang, Hangtao, Shengshan Hu, Yichen Wang, Leo Yu Zhang, Ziqi Zhou, Xianlong Wang, Yanjun Zhang e Chao Chen. "Detector Collapse: Backdooring Object Detection to Catastrophic Overload or Blindness in the Physical World". In Thirty-Third International Joint Conference on Artificial Intelligence {IJCAI-24}. California: International Joint Conferences on Artificial Intelligence Organization, 2024. http://dx.doi.org/10.24963/ijcai.2024/185.
Testo completoAbstract (sommario):
Object detection tasks, crucial in safety-critical systems like autonomous driving, focus on pinpointing object locations. These detectors are known to be susceptible to backdoor attacks. However, existing backdoor techniques have primarily been adapted from classification tasks, overlooking deeper vulnerabilities specific to object detection. This paper is dedicated to bridging this gap by introducing Detector Collapse (DC), a brand-new backdoor attack paradigm tailored for object detection. DC is designed to instantly incapacitate detectors (i.e., severely impairing detector's performance and culminating in a denial-of-service). To this end, we develop two innovative attack schemes: Sponge for triggering widespread misidentifications and Blinding for rendering objects invisible. Remarkably, we introduce a novel poisoning strategy exploiting natural objects, enabling DC to act as a practical backdoor in real-world environments. Our experiments on different detectors across several benchmarks show a significant improvement (~10%-60% absolute and ~2-7x relative) in attack efficacy over state-of-the-art attacks.
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Veirs, Kirk, Victor K. F. Chia e Gerd M. Rosenblatt. "Application of Position-Sensitive, Photon-Counting Detectors in Raman Spectroscopy". In Laser Applications to Chemical Analysis. Washington, D.C.: Optica Publishing Group, 1987. http://dx.doi.org/10.1364/laca.1987.wa8.
Testo completoAbstract (sommario):
Raman spectroscopy has benefited from recent advances in the technology of lasers, optics, thin film interference filters and multichannel detectors. A new generation of imaging detectors based upon microchannel plates with position sensitive anodes may increase the sensitivity of Raman spectroscopy. Such detectors would be particularly useful to Raman spectroscopy without surface enhancement. A position-sensitive detector (PSD) with resolution of 70 microns in both the x and y axis on a 1 inch diameter photocathode with a dark count of 30 counts per second (cps) was used. The signal and signal to noise ratio (SNR) of this detector was compared to the standard intensified photodiode array (IPDA) detector using the Raman spectra of the fundamental vibration of O2 in air.
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Slavinska, Irita, Vladimirs Jemeljanovs e Maris Ziemelis. "Efficiency of autonomous smoke detectors depending on operation time period". In 22nd International Scientific Conference Engineering for Rural Development. Latvia University of Life Sciences and Technologies, Faculty of Engineering, 2023. http://dx.doi.org/10.22616/erdev.2023.22.tf210.
Testo completoAbstract (sommario):
Every year there are a lot of fires in Latvia in the residential sector and in a great number of fires people are killed. Fires often break out in the middle of the night or early in the morning, when people sleep and do not feel smoke starting to spread through housing. Fatal fires are very common fires with a small area of burning when people die inhaling poisonous burning products without even waking up. Thus, the autonomous smoke detector is compulsory equipment that should be in every home. In the event of a fire, it helps inform the inhabitants of the fires that have broken out and provides them with the opportunity to evacuate from filled with smoke rooms in good time. And time shows that smoke detectors are effective means and there are several cases where people have only saved themselves from burning homes due to hearing the sound of the smoke detector. Meanwhile, as the mandatory installation of a smoke detector in each dwelling was introduced, the Latvian State Fire and Rescue Service notes that there are more and more cases where smoke detectors are installed in dwellings, but do not work or perform their primary and sole function – to inform people of the smoke by a high sound signal. The authors of the article examined the reasons for the failure of smoke detectors, which have been identified in other countries and conducted an experiment where the effect of the dirtiness of the smoke detectors on the failure of them when smoke occurs, was checked. As well as a survey among residents of Latvia was conducted regarding whether they had installed smoke detectors in their dwellings, how much and in what rooms the detectors had been installed, what prompted them to purchase smoke detectors, whether before installation people had read the instructions for use and were informed how to correctly install smoke detectors, whether they know that for smoke detector maintenance inspection of them had to be performed and whether people did that. As part of this study, the authors examined how the service time of smoke detectors changes and whether it changes if the smoke detector is operated in different rooms and for different time periods, but their regular cleaning from dust and other dirt is not done. As well as it was checked how quickly the smoke detector would start working if the fire breaks out in the next room and the time for a person to evacuate from those rooms was calculated. The operational efficiency of the autonomous smoke detector was examined and recommendations for effective extension of its operational capacity were put forward.
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Urey, Hakan, e William T. Rhodes. "Image Processing Using Pyroelectric Detectors". In Optics in Computing. Washington, D.C.: Optica Publishing Group, 1997. http://dx.doi.org/10.1364/oc.1997.othc.3.
Testo completoAbstract (sommario):
Recent research and development on uncooled 2-D pyroelectric detector arrays makes possible new image processing applications. Pyroelectric detectors are fundamentally different from other detectors in that they are AC-mode devices: they respond only to variations in the incident light intensity and produce no detectable output for a constant input irradiance.1 A rotating chopper is typically placed in front of a pyroelectric camera to modulate the incident radiation and thereby produce a signal proportional to the incident image scene intensity.
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Shaaban, Noha, Wael El Gammal e Hesham Nasif. "Optimization of Dead-Layer Thickness for a HPGe Detector Using UCODE-MCNP Codes". In 17th International Conference on Nuclear Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/icone17-75939.
Testo completoAbstract (sommario):
The use of modeling programs to predict the response of HPGe detectors is increasing in importance due to the extensive laboratory work, both in term of source preparations and measuring time. MCNP code is a powerful and useful tool for the simulation of Ge-detector efficiency calibration. The experimental efficiency data and MCNP calculations based only on the known physical measurements of the HPGe crystal do not agree well in some detectors. Detector construction materials and surface dead layers must be well specified. The dead layer of Ge detector is one of the most important factors that affect the calculations. In addition, and if provided by the manufacturer, the dead layer may changes with time. Consequently, it is necessary to optimize the thickness of the detector’s dead layer in order to obtain more accurate results for the efficiency of the detector using Monte Carlo calculations. Our approach consists of employing hybrid UCODE-MCNP codes to optimize the dead layer of the Ge-crystal aiming at decreasing discrepancies between experimental and simulated data of the Ge detector efficiency. UCODE has two attributes that are not jointly available in other inverse models: (1) the ability to work with any mathematically based model or pre- or post processor with ASCII or text only input and output files, and (2) the inclusion of more informative statistics.
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Ko, Samuel C. K., Aaron Y. K. Yan e H. W, Li. "Calibration of ultrasonic flaw detectors". In NCSL International Workshop & Symposium. NCSL International, 2014. http://dx.doi.org/10.51843/wsproceedings.2014.55.
Testo completoAbstract (sommario):
The Standards and Calibration Laboratory (SCL) has set up facilities to provide calibration for ultrasonic flaw detectors in accordance with the international standard EN12668-1:2010. The calibration covers all the periodic and repair tests (the group 2 tests) required in the standard EN12668-1:2010 for checking the performance of the ultrasonic instruments, including its stability, transmitter pulse parameters, receiver response parameters and time-base linearity. During the calibration, the ultrasonic flaw detector’s transmitter is connected to a combination of delay generator and function generator which simulates a delayed version of the transmitted signal as the reflected signal. The simulated reflected signal is then fed to the receiver of the ultrasonic flaw detector. The stabilities over time and voltage variation of the received waves are measured. The receiver frequency response is obtained by sweeping the function generator’s frequency. Other performance parameters of the receiver such as gain accuracy and linearity are calibrated by comparing gain steps with step attenuators. Lastly a burst of pulse waves are generated by the delay/pulse generator to simulate a burst of reflected waves to check the linearity of the time base.
Rapporti di organizzazioni sul tema "Detectors"
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Harris, D. Subspace Detectors: Theory. Office of Scientific and Technical Information (OSTI), luglio 2006. http://dx.doi.org/10.2172/900081.
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Karpius, Peter Joseph, Theresa Elizabeth Cutler, George Espy IV McKenzie, Jacob Stinnett e Katrina Ann Stults. Detectors and Data. Office of Scientific and Technical Information (OSTI), maggio 2020. http://dx.doi.org/10.2172/1631551.
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Wilson, Tiffany M. S., Michael J. King e F. Patrick Doty. Plastic neutron detectors. Office of Scientific and Technical Information (OSTI), dicembre 2008. http://dx.doi.org/10.2172/946574.
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Hennig, Wolfgang. High-speed, multi-channel detector readout electronics for fast radiation detectors. Office of Scientific and Technical Information (OSTI), giugno 2012. http://dx.doi.org/10.2172/1043826.
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Carmichael, Joshua Daniel. Multi-Channel Correlation Detectors: Accounting for and Reducing Non-target Detections. Office of Scientific and Technical Information (OSTI), giugno 2015. http://dx.doi.org/10.2172/1186031.
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Harris, D., e T. Paik. Subspace Detectors: Efficient Implementation. Office of Scientific and Technical Information (OSTI), luglio 2006. http://dx.doi.org/10.2172/898451.
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Andrews, Mike, Geoffrey Mills, Alysia Marino, Eric Zimmerman, Charles Lane e Hans Bern. LBNE-NuMI Muon Detectors. Office of Scientific and Technical Information (OSTI), agosto 2013. http://dx.doi.org/10.2172/1128253.
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Cardimona, David. Advanced Space-Based Detectors. Fort Belvoir, VA: Defense Technical Information Center, luglio 2014. http://dx.doi.org/10.21236/ada606444.
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Bluzer, Nathan, e Martin G. Forrester. Multispectral Superconducting Quantum Detectors. Fort Belvoir, VA: Defense Technical Information Center, marzo 1999. http://dx.doi.org/10.21236/ada361795.
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Bluzer, Nathan, e Martin G. Forrester. LWIR Superconducting Quantum Detectors. Fort Belvoir, VA: Defense Technical Information Center, agosto 1995. http://dx.doi.org/10.21236/ada298885.
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