共查询到20条相似文献,搜索用时 15 毫秒
1.
Thick-film 20 mol% ZnO-doped RuO2 sensing electrodes (SEs) were fabricated by screen-printing technique on the platinised alumina substrate of the planar electrochemical dissolved oxygen (DO) sensor. The effect of ZnO doping on morphology, electrochemical properties and sensing characteristics of the sensor was investigated. It was found that ZnO doping has not only improved the SE structure, but has also enhanced selectivity of the DO sensor. Selectivity testing exhibited that the presence of Cl−, Li+, SO42−, NO3−, Ca2+, PO43−, Mg2+, Na+ and K+ with a concentration range of 10−7 to 10−1 mol/L in the solution had practically no effect on the sensor's emf. The reason in enhancement of the sensor characteristics could be related to the establishment of the better structured SE as more advanced crystallization is achieved for the doped RuO2-SE. 相似文献
2.
Ali K. Yetisen Nan Jiang Carmen M. Castaneda Gonzalez Zeynep Izlen Erenoglu Jie Dong Xingchen Dong Simon Stößer Martin Brischwein Haider Butt Maria F. Cordeiro Martin Jakobi Oliver Hayden Alexander W. Koch 《Advanced materials (Deerfield Beach, Fla.)》2020,32(6):1906762
The quantitative analysis of tear analytes in point-of-care settings can enable early diagnosis of ocular diseases. Here, a fluorescent scleral lens sensor is developed to quantitatively measure physiological levels of pH, Na+, K+, Ca2+, Mg2+, and Zn2+ ions. Benzenedicarboxylic acid, a pH probe, displays a sensitivity of 0.12 pH units within pH 7.0–8.0. Crown ether derivatives exhibit selectivity to Na+ and K+ ions within detection ranges of 0–100 and 0–50 mmol L−1, and selectivities of 15.6 and 8.1 mmol L−1, respectively. A 1,2 bis(o-aminophenoxy)ethane-N,N,-N',N'-tetraacetic-acid-based probe allows Ca2+ ion sensing with 0.02–0.05 mmol L−1 sensitivity within 0.50–1.25 mmol L−1 detection range. 5-Oxazolecarboxylic acid senses Mg2+ ions, exhibiting a sensitivity of 0.10–0.44 mmol L−1 within the range of 0.5–0.8 mmol L−1. The N-(2-methoxyphenyl)iminodiacetate Zn2+ ion sensor has a sensitivity of 1 µmol L−1 within the range of 10–20 µmol L−1. The fluorescent sensors are subsequently multiplexed in the concavities of an engraved scleral lens. A handheld ophthalmic readout device comprising light-emitting diodes (LEDs) and bandpass filters is fabricated to excite as well as read the scleral sensor. A smartphone camera application and an user interface are developed to deliver quantitative measurements with data deconvolution. The ophthalmic system enables the assessment of dry eye severity stages and the differentiation of its subtypes. 相似文献
3.
R. Blaauwgeers M. Blazkova M. Človečko V. B. Eltsov R. de Graaf J. Hosio M. Krusius D. Schmoranzer W. Schoepe L. Skrbek P. Skyba R. E. Solntsev D. E. Zmeev 《Journal of Low Temperature Physics》2007,146(5-6):537-562
Commercial quartz oscillators of the tuning-fork type with a resonant frequency of ∼ 32 kHz have been investigated in helium
liquids. The oscillators are found to have at best Q values in the range 105–106, when measured in vacuum below 1.5 K. However, the variability is large and for very low temperature operation the sensor
has to be preselected. We explore their properties in the regime of linear viscous hydrodynamic response in normal and superfluid
3He and 4He, by comparing measurements to the hydrodynamic model of the sensor.
Dedicated to former JLTP editor Frank Pobell. 相似文献
4.
Mohammad Reza Ganjali Parviz Norouzi Alireza Atrian Farnoush Faridbod Soraia Meghdadi Masoud Giahi 《Materials science & engineering. C, Materials for biological applications》2009,29(1):205-210
The biological properties of the lutetium as well as other lanthanide ions, primarily based on their similarity to calcium, have been the bases for research into potential therapeutic applications of lanthanide series since the early part of the twentieth century. In this research, a Lu(III) potentiometric membrane sensor based on N,N′-bis(2-pyridinecarboxamide)-1,2-ethane (PCAE) is described. The sensor exhibits a Nernstian response over a concentration range of 1.0 × 10? 6 mol L? 1–1.0 × 10? 1 mol L? 1, with a detection limit of 6.0 × 10? 7 mol L? 1. The best performance was achieved with a membrane composition, consisting of 30% PVC, 63% o-nitrophenyl octyl ether (NPOE), 5% PCAE and 2% sodium tetraphenylborate (NaTPB). It was found that at the pH range of 4.0–9.0, the potential response of the sensor was not affected by the pH. Furthermore, the electrode presents satisfactory reproducibility, very fast response time (5 s) and relatively good discriminating ability for Lu(III) ions with respect to many common cations and other lanthanide ions. The sensor has been applied to the determination of Lu(III) in human serum and in some soil samples where domestic devices were stored. 相似文献
5.
Zehui Li Rongji Liu Cheng Tang Zhuoya Wang Xiao Chen Yuheng Jiang Chizhong Wang Yi Yuan Wenbo Wang Dongbin Wang Shuning Chen Xiaoyuan Zhang Qiang Zhang Jingkun Jiang 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(15)
In situ monitoring of hydrogen peroxide (H2O2) during its production process is needed. Here, an electrochemical H2O2 sensor with a wide linear current response range (concentration: 5 × 10?8 to 5 × 10?2 m ), a low detection limit (32.4 × 10?9 m ), and a high sensitivity (568.47 µA mm ?1 cm?2) is developed. The electrocatalyst of the sensor consists of cobalt nanoparticles and atomic Co‐Nx moieties anchored on nitrogen doped carbon nanotube arrays (Co‐N/CNT), which is obtained through the pyrolysis of the sandwich‐like urea@ZIF‐67 complex. More cobalt nanoparticles and atomic Co‐Nx as active sites are exposed during pyrolysis, contributing to higher electrocatalytic activity. Moreover, a portable screen‐printed electrode sensor is constructed and demonstrated for rapidly detecting (cost ≈40 s) H2O2 produced in microbial fuel cells with only 50 µL solution. Both the synthesis strategy and sensor design can be applied to other energy and environmental fields. 相似文献
6.
Sherif A. El‐Safty M. A. Shenashen A. Shahat 《Small (Weinheim an der Bergstrasse, Germany)》2013,9(13):2288-2296
Methods for the continuous monitoring and removal of ultra‐trace levels of toxic inorganic species (e.g., mercury, copper, and cadmium ions) from aqueous media such as drinking water and biological fluids are essential. In this paper, the design and engineering of a simple, pH‐dependent, micro‐object optical sensor is described based on mesoporous aluminosilica pellets with an adsorbed dressing receptor (a porphyrinic chelating ligand). This tailor‐made optical sensor permits ultra‐fast (≤ 60 s), specific, pH‐dependent visualization and removal of Cu2+, Cd2+, and Hg2+ at sub‐picomolar concentrations (~10?11 mol dm?3) from aqueous media, including drinking water and a suspension of red blood cells. The acidic active acid sites of the pellets consist of heteroatoms arranged around uniformly shaped pores in 3D nanoscale gyroidal mesostructures densely coated with the chelating ligand. The sensor can be used in batch mode, as well as in a flow‐through system in which sampling, target ion recognition and removal, and analysis are integrated in a highly automated and efficient manner. Because the pellets exhibit long‐term stability, reproducibility, and versatility over a number of analysis/regeneration cycles, they can be expected to be useful for the fabrication of inexpensive sensor devices for naked‐eye detection of toxic pollutants. 相似文献
7.
Hassan Ali Zamani Ali Arvinfar Fatemeh Rahimi Alihossien Imani Mohammad Reza Ganjali Soraia Meghdadi 《Materials science & engineering. C, Materials for biological applications》2011,31(2):307-312
A new Pr3+ poly vinyl chloride PVC membrane sensor based on a membrane containing 3% N,N′-bis(4-hydroxysalicylidene)-1-3-phenylenediamine (HSPDA) as an ionophore, 2% sodium tetraphenyl borate (NaTPB) as an anionic additive, 65% benzyl acetate (BA) as solvent mediator and 30% poly(vinyl chloride) was prepared. This sensor responds to praseodymium ion in a wide linear dynamic range of 1.0 × 10?6 to 1.0 × 10?2 mol L?1 with Nernstian slope of 19.8 ± 0.4 mV per decade and a detection limit of 5.7 × 10?7 mol L? 1 in pH range of 3.1 to 9.8. It has a fast response time of ~5 s in the whole concentration range, and can be used for at least 2 months without any considerable divergences in the potentials. The proposed sensor displays an excellent selectivity for Pr3+ ions with respect to a large number of alkali, alkaline earth, transition and heavy metal ions. The developed sensor was successfully applied as an indicator electrode in Pr3+ ion potentiometric titration with EDTA, and in direct determination of fluoride ion in two mouth wash samples. 相似文献
8.
Mohammad Bagher Gholivand Moslem Mohammadi Mohammad Kazem Rofouei 《Materials science & engineering. C, Materials for biological applications》2010,30(6):847-852
A new optical sensor for highly sensitive and selective determination of mercury(II) ion in aqueous solutions is developed. The mercury sensing membrane was prepared by incorporating 1,3-di(2-methoxyphenyl)triazene (MPT) as chromoionophore in the plasticized PVC membrane containing tris(2-ethylhexyl)phosphate (TEHP) as plasticizer. The proposed sensor displays a wide linear range of 9.0 × 10?10–2.5 × 10?7 M with a low detection limit of 2.0 × 10?10 M in aqueous solutions at pH 4.0. This sensor has a relatively fast response time of less than 5 min. In addition to high stability and reproducibility, it shows a unique selectivity towards Hg2+ ion with respect to common coexisting cations. The sensor can readily be regenerated by exposure to a solution of sodium iodide (0.01 M). The proposed optode was applied to the determination of Hg2+ in water samples. 相似文献
9.
Magnetic Susceptibility Study of Sub‐Pico‐emu Sample Using a Micromagnetometer: An Investigation through Bistable Spin‐Crossover Materials
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Souleymane Kamara Quang‐Hung Tran Vincent Davesne Gautier Félix Lionel Salmon Kunwoo Kim CheolGi Kim Azzedine Bousseksou Ferial Terki 《Advanced materials (Deerfield Beach, Fla.)》2017,29(46)
A promising and original method to study the spin‐transition in bistable spin‐crossover (SCO) materials using a magnetoresistive multiring sensor and its self‐generated magnetic field is reported. Qualitative and quantitative studies are carried out combining theoretical and experimental approaches. The results show that only a small part of matter dropped on the sensor surface is probed by the device. At a low bias‐current range, the number of detected nanoparticles depends on the amplitude of the current. However, in agreement with the theoretical model, the stray voltage from the particles is proportional to the current squared. By changing both the bias current and the concentration of particle droplet, the thermal hysteresis of an ultrasmall volume, 1 × 10?4 mm3, of SCO particles is measured. The local probe of the experimental setup allows a highest resolution of 4 × 10?14 emu to be reached, which is never achieved by experimental methods at room temperature. 相似文献
10.
《Journal of Modern Optics》2013,60(12):1563-1570
The dependence of the leakage of the LP01 mode of a polished single-mode fibre section on the refractive index of an external medium provides non-ambiguous intensity modulation of the guided wave and a single-point in situ calibration of a sensor based on this refractive index, or temperature, transducing mechanism. Refractive index and temperature resolution of 10m4 and 0·1°, has been obtained over an adjustable range of 0·02 and 80°, respectively. 相似文献
11.
Delu Chen Xinrong Zhi Yifan Xia Shuhan Li Benbo Xi Chun Zhao Xin Wang 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(36):2301196
Memristor with digital and analog bipolar bimodal resistive switching offers a promising opportunity for the information-processing component. However, it still remains a huge challenge that the memristor enables bimodal digital and analog types and fabrication of artificial sensory neural network system. Here, a proposed CsPbBr3-based memristor demonstrates a high ON/OFF ratio (>103), long retention (>104 s), stable endurance (100 cycles), and multilevel resistance memory, which acts as an artificial synapse to realize fundamental biological synaptic functions and neuromorphic computing based on controllable resistance modulation. Moreover, a 5 × 5 spinosum-structured piezoresistive sensor array (sensitivity of 22.4 kPa−1, durability of 1.5 × 104 cycles, and fast response time of 2.43 ms) is constructed as a tactile sensory receptor to transform mechanical stimuli into electrical signals, which can be further processed by the CsPbBr3-based memristor with synaptic plasticity. More importantly, this artificial sensory neural network system combined the artificial synapse with 5 × 5 tactile sensing array based on piezoresistive sensors can recognize the handwritten patterns of different letters with high accuracy of 94.44% under assistance of supervised learning. Consequently, the digital−analog bimodal memristor would demonstrate potential application in human–machine interaction, prosthetics, and artificial intelligence. 相似文献
12.
Abstract The flow in an enclosed co‐rotating disk pair is investigated by Laser Doppler Velocimetry (LDV) measurements and flow visualizations. First, the typical flow structure at Re = 5.25 × 105 and S = 0.09 is clarified. The flow fields in the r – θ and the r – z planes are both investigated and then divided into several flow regions based on the distinct flow types observed. The flow regions found in the two different planes are also compared and integrated. Second, with S fixed, the dependence of the flow field structure upon the Reynolds number is discussed. Three regimes of the r – θ plane flow with different Reynolds numbers are identified based on the measured mean velocity and spectral intensity. When Re < 1.6 × 105, no solid body region is found and the flow is in a laminar regime. In the range 1.6 × 105 ≤ Re ≤ 2.0 × 106, the solid body region and the outer region vortices coexist, and an empirical equation is developed to estimate the number of vortices. When Re > 2.0 × 106, the flow becomes turbulent. As Re increases from 9.3 × 104 to 5.25 × 105, the spectral intensity initially increases and then decreases before increasing again to an even higher level, resulting in an increasing sawtooth pattern. 相似文献
13.
D. S. Filimonov Ya. A. Kesler K. V. Pokholok I. A. Presnyakov 《Inorganic Materials》2000,36(4):309-317
Heterovalent substitution of As5+, Sb5+, V5+, and Sn4+ diamagnetic ions in CuCr2S4 was studied. The results show that, similar to other 3d10 diamagnetic ions, the As5+ ions occupy only tetrahedral interstices in the close packing of sulfur ions, while the Sb5+ and Sn4+ 4d10 ions, as well as the Sc3+, Ti4+, and V5+ 3d0 ions occupy only octahedral sites. A new compound of composition Cu3AsCr8S16 was synthesized and characterized. It crystallizes in an orthorhombic (sp. gr.Pmm2) spinel-derived structure containing ordered Cu and As ions in tetrahedral sites(a = 13.942 ± 0.004 Å,b = 6.878 ± 0.002 Å,c = 19.692 ± 0.006 Å, Z = 4, V = 1888.43 ± 0.92 Å). The CuCr1.5Sb0.5S4 spinel phase is found to crystallize in sp. gr.Fd3m (a = 10.009 ± 0.002 Å,u = 0.3815 ± 0.0004 Å) with partial ordering on octahedral sites. 相似文献
14.
W. E. Alnaser M. M. Zein M. N. Khan S. S. Al-Dallal A. M. Memon M. J. Al-Othman 《Journal of Materials Science》1994,29(2):482-485
Mechanical losses spectroscopy of two superconducting Y1Ba2Cu3O7–x
samples (T
c=93 K) measured at 5, 10, 20 and 30 MHz revealed four peaks. As the frequency of measurement was increased, the peaks shifted to higher temperatures. The relaxation process was found to have an activation enthalpy of 0.188, 0.092, 0.209 and 0.314 eV with an attempt frequency,f
o, equal to 2.46 × 1015, 5.95 × 1010, 1.64 × 1014, and 7.82 × 1013 Hz for P1, P2, P3 and P4 peaks, respectively. The mechanism responsible for these relaxation peaks is discussed. The infrared spectra of some of these compounds provide evidence for oxygen rearrangement on going from tetragonal to orthorhombic phase. X-ray diffraction analysis shows that these compounds correspond to a single phase which is an orthorhombic perovskite structure. 相似文献
15.
The effect of rare-earth doping (R = Gd, Dy, Ho) to different levels (0, 10?5, 10?4, 10?3, 10?2, and 10?1 at %) on threshold switching and low-frequency current oscillations in single crystals of indium selenide, a layered III–VI semiconductor, has been studied in broad ranges of temperatures (77–400 K), wavelengths (0.30–3.50 μm), and illuminances (up to ~102 lx). The results are interpreted in terms of the anisotropic chemical bonding in n-InSe and its response to rare-earth doping. 相似文献
16.
K. H. Kang S. H. Na C. J. Park Y. H. Kim K. C. Song S. H. Lee S. W. Kim 《International Journal of Thermophysics》2009,30(4):1386-1395
As a part of the DUPIC (direct use of spent PWR fuel in CANDU reactors) fuel development program, the thermal expansion of
simulated spent fuel pellets with dissolved fission products has been studied by using a thermo-mechanical analyzer (TMA)
in the temperature range from 298 K to 1773 K to investigate the effects of fission products forming solid solutions in a
UO2 matrix on the thermal expansions. Simulated fuels with an equivalent burn-up of (30 to 120) GWd/tU were used in this study.
The linear thermal expansions of the simulated fuel pellets were higher than that of UO2, and the difference between these fuel pellets and UO2 increased monotonically with temperature. For the temperature range from 298 K to 1773 K, the values of the average linear
thermal expansion coefficients for UO2 and simulated fuels with an equivalent burn-up of (30, 60, and 120) GWd/tU are 1.19 × 10−5 K−1, 1.22 × 10−5 K−1, 1.26 × 10−5 K−1, and 1.32 × 10−5 K−1, respectively. 相似文献
17.
Hassan Ali Zamani Farnoush Faridbod Mohammad Reza Ganjali 《Materials science & engineering. C, Materials for biological applications》2013,33(2):608-612
A novel Dy(III) ion-selective PVC membrane sensor was made using a new synthesized organic compound, 3,4-diamino-N′-((pyridin-2-yl)methylene)benzohydrazide (L) as an excellent sensing element. The electrode showed a Nernstian slope of 19.8 ± 0.6 mV per decade in a wide concentration range of 1.0 × 10? 6–1.0 × 10? 2 mol L? 1, a detection limit of 5.5 × 10? 7 mol L? 1, a short conditioning time, a fast response time (< 10 s), and high selectivity towards Dy(III) ion in contrast to other cations. The proposed sensor was successfully used as an indicator electrode in the potentiometric titration of Dy(III) ions with EDTA. The membrane sensor was also applied to the F– ion indirect determination of some mouth washing solutions and to the Dy3 + determination in binary mixtures. 相似文献
18.
N. N. Basargin E. R. Oskotskaya P. E. Simakov Yu. G. Rozovskii 《Inorganic Materials》2010,46(15):1637-1639
The technique of spectrophotometric determination of Zr(IV) in rock based on preliminary individual extraction (concentration) of this element by a polymer chelating sorbent, namely, polystyrene-2-oxi-(azo-1)-2′-oxi-3′,5′-dinitrobenzene, is described. The determination is not hindered by 6 ×104-fold mass amounts of Na+, K+, Ca2+, Mg2+, Ba2+, and Sr2+; 2 × 104-fold mass amounts of Al3+, Cu2+, Pb2+, Co2+, Ni2+, Zn2+, and Cd2+; 5 × 103-fold mass amounts of Sn2+, Fe2+, Be2+, and Ce3+; and 2 × 103-fold mass amounts of Fe3+, Sc3+, and Y3+. Quantitative extraction of the element takes place in static conditions within the acidity range of 1 M HCl—2.5 pH. The correctness of the technique was tested by the analysis of standard rock specimens. The relative standard deviation is 0.01–0.04 during determination of Zr(IV) at the concentration level of n × 10?2-n × 10?4%. 相似文献
19.
Pyrolysis of five coal tar pitches with wide ranging characteristics, made from the same coal tar precursor, has been studied under nitrogen pressures of 105, 50×105, 90×105 and 160×105 Pa, at a temperature of 550 °C. The residues were further heat-treated to 900 °C to obtain the ultimate normal (105 Pa) and pressure coking yields of these pitches. The literature states that for pitches with relatively lower softening points the carbonization pressure not only increases the coking yield but also lowers the temperature at which the pyrolysis is complete. This is seen to hold true for the present set of pitches, having a much wider range of softening points. Further, one of the pitches, earlier reported by us to be a good preforming pitch for carbon-carbon composites, gave an ultimate coking yield of 88% on subjection to a nitrogen pressure of 160×105 Pa at 550 °C followed by ambient pressure carbonization to 900 °C. It thus appears that a carbonization pressure of 160×105 Pa for a suitable preforming pitch can act as a reasonably good alternative to the expensive hot isostatic pressure impregnation carbonization technique employed in the production of carbon-carbon composites. 相似文献
20.
M.R. Ganjali M. Hosseini A. Ghafarloo M. Khoobi F. Faridbod A. Shafiee P. Norouzi 《Materials science & engineering. C, Materials for biological applications》2013,33(7):4140-4143
(E)-2-(1-(4-hydroxy-2-oxo-2H-chromen-3-yl)ethylidene)hydrazinecarbothioamide (L) has been used to detect trace amounts of praseodymium ion in acetonitrile–water solution (MeCN/H2O) by fluorescence spectroscopy. The fluorescent probe undergoes fluorescent emission intensity enhancement upon binding to Pr3 + ions in MeCN/H2O (9/1:v/v) solution. The fluorescence enhancement of L is attributed to a 1:1 complex formation between L and Pr3 +, which has been utilized as the basis for selective detection of Pr3 +. The sensor can be applied to the quantification of praseodymium ion with a linear range of 1.6 × 10? 7 to 1.0 × 10? 5 M. The limit of detection was 8.3 × 10? 8 M. The sensor exhibits high selectivity toward praseodymium ions in comparison with common metal ions. The proposed fluorescent sensor was successfully used for determination of Pr3 + in water samples. 相似文献