Search

Constant, real-time temperature monitoring of the supercapacitors for efficient energy usage is in high demand and seems to be crucial for further development of those elements. A fiber-optic sensor can be an effective optoelectronic device dedicated for in-situ temperature monitoring of supercapacitors. In this work, the application of the fiber-optic microstrucutre with thin zinc oxide (ZnO) coating fabricated in the atomic layer deposition process applied as a temperature sensor is reported. Such a structure was integrated with supercapacitors and used for the temperature measurements. Described sensors are built with the utility of the standard optical telecommunication fibers. The inner temperature of the supercapacitor was investigated in the range extending from 30 °C to 90 °C with a resolution equal to 5 °C. The sensitivity of temperature measurement is about 109.6 nW °C−1. The fitting of the sensor was achieved with a correlation coefficient R 2 = 0.97.

Atomic and molecular data are at the origin of the atmospheres of planetary and stellar objects discoveries. Based on the laboratory astrophysics and the computational molecular spectroscopy, the interpretation of this data can give the chemical compositions and temperatures of these astrophysical systems. The detection and the identification of the SiN radical in the interstellar medium has drawn the attention to the gas phase chemistry and the evidence of a link between the interstellar chemistry of silicon and that of nitrogen. The quantum chemistry methods used to predict the spectroscopic properties of the SiN molecule can be calibrated with some available experimental results. In order to obtain reliable theoretical data that may help in the interpretation of interstellar or laboratory spectra concerning the SiN molecule, we performed theoretical calculation of 31 low-lying electronic state, below 66000 cm−1, of the molecule SiN by using the Complete Active Space Self Consistent Field (CASSCF) method followed by the Multi Reference Configuration Interaction with Davidson correction MRCI+Q. The potential energy along with the dipole moment curves of these states have been calculated along with the spectroscopic constants Re, ωe, Be, and Te. The Rotation-vibration lines for the considered electronic states of SiN molecule were obtained by direct solution of the nuclear motion Schrödinger equation using the canonical approach with program Rovib-1. By comparing our investigated values of the calculated vibrational energy Ev, the rotational constant Bv and the turning points Rmin and Rmax. with those available in literature shows a very good agreement. To the best of our knowledge nine new electronic states have been studied here for the first time that have not been observed yet.

ZnO nanowires (NWs)/Cu2O–Ag core–shell nanostructures (NSs) have been synthesized by electrochemical deposition method on ITO-coated glass substrates in order to improve the efficiency of the type-II transition of core–shell ZnO NWs/Cu2O–Ag NSs. The morphologies of the obtained NSs were studied by scanning electron microscopy confirming the presence of core–shell NSs. The crystalline proprieties were analyzed by x-ray diffraction and micro-Raman measurement: wurtzite ZnO and cuprit Cu2O phase were founded. The presence of Ag content in core–shell NS was detected by EDX. Optical measurement reveals an additional contribution δE at about 1.72 eV attributed to the type-II interfacial transition between the valance band of cuprit−Cu2O and the conduction band of W−ZnO. The effect of the Ag doping into the type-II transition was investigated. A red shift of the type-II transition was detected according to the Ag concentration. These materials could have potential applications in photocatalytic and photovoltaic fields.

Characterizing the mechanical response of isolated nanostructures is vitally important to fields such as microelectromechanical systems (MEMS) where the behaviour of nanoscale contacts can in large part determine system reliability and lifetime. To address this challenge directly, single crystal gold nanodots are compressed inside a high resolution scanning electron microscope (SEM) using a nanoindenter equipped with a flat punch tip. These structures load elastically, and then yield in a stochastic manner, at loads ranging from 16 to 110 microN, which is up to five times higher than the load necessary for flow after yield. Yielding is immediately followed by displacement bursts equivalent to 1-50% of the initial height, depending on the yield point. During the largest displacement bursts, strain energy within the structure is released while new surface area is created in the form of localized slip bands, which are evident in both the SEM movies and still-images. A first order estimate of the apparent energy release rate, in terms of fracture mechanics concepts, for bursts representing 5-50% of the structure's initial height is on the order of 10-100 J m(-2), which is approximately two orders of magnitude lower than bulk values. Once this initial strain burst during yielding has occurred, the structures flow in a ductile way. The implications of this behaviour, which is analogous to a brittle to ductile transition, are discussed with respect to mechanical reliability at the micro- and nanoscales.

Batch-fabricated SiC nanowires were heated under an ammoniac flow up to 1400 °C. The ensuing product was characterized by SEM, HRTEM, EDX and XRD. As we found, SiC nanowires were completely converted into faceted α-Si3N4 nanorods with diameters ranging from 10 to 500 nm and lengths lower than 10 µm. These nanorods present hexagonal cross sections. We suggest a growth mechanism based on the progressive elimination of carbon through hydrogenation reactions and the growth of silicon nitride nanorods via the high-temperature nitridation of silicon.