Ayşe Evrim Bulgurcuoğlu, Yaşar Karabul, Mehmet Kiliç, Zeynep Güven Özdemir, Seda Erdönmez, Banu Süngü Misirlioğlu, Mustafa Okutan and Orhan İçelli
In this work, polypyrrole and polythiophene conducting polymers (CPs) have been synthesized and doped with volcanic basalt rock (VBR) in order to improve their dielectric properties for technological applications. The structure and morphology of the composites with different VBR doping concentrations were characterized by FT-IR and SEM analyses. The best charge storage ability was achieved for maximum VBR doping concentration (50.0 wt.%) for both CPs. Dielectric relaxation types of the composites were determined as non-Debye type due to non-zero absorption coefficient and observation of semicircles whose centers were below Z′ axis at the Nyquist plots. It was also ascertained that VBR doping makes the molecular orientation easier than for non-doped samples and reduced energy requirement of molecular orientation. In addition, AC conductivity was totally masked by DC conductivity for all samples at low frequency.
Simulated transmission spectra for tapered fibers with no taper, one taper and two tapers in the near infrared wavelength range, calculated by Finite-Difference-Time-Domain method are currently presented. Transmission peak positions tend to shift to the shorter wavelength when the taper deformation is added to the fiber or the taper width gets narrower. The thickness sensitivity for the tapered structures with different taper thicknesses is about 2.28e-3 nm·μm−1. There is an interference structure in the electric field distribution images, which reveals in the fiber structures. The transmission spectra for the fiber without taper, one taper and two-tapered structures were simulated in near infrared wavelength by FDTD. The transmission spectra for tlated in near infrared wavelength by FDTD. The sensitivity of the fiber was about 50 nm × RIU−1 and it had better refractive index detection. The tapered fiber can be applied to the bio-chemical sensors and physical deformation testing.
A. Sadoun, S. Mansouri, M. Chellali, N. Lakhdar, A. Hima and Z. Benamara
In this work, we have presented a theoretical study of Au/Ni/GaN Schottky diode based on current-voltage (I-V) measurement for temperature range of 120 K to 400 K. The electrical parameters of Au/Ni/GaN, such as barrier height (Φb), ideality factor and series resistance have been calculated employing the conventional current-voltage (I-V), Cheung and Chattopadhyay method. Also, the variation of Gaussian distribution (P (Φb)) as a function of barrier height (Φb) has been studied. Therefore, the modified () relation has been extracted from (I-V) characteristics, where the values of ΦB0 and have been found in different temperature ranges. The obtained results have been compared to the existing experimental data and a good agreement was found.
L-cysteine hydrogen fluoride (LCHF) single crystals were grown from aqueous solution. Single crystal X-ray diffraction, FT-IR, UV-Vis-NIR, and TG-DTA were used to test the grown crystals. The specimen dielectric and mechanical behaviors were also studied. Powder X-ray diffraction of the grown crystal was recorded and indexed. The optical properties of the LCHF crystal were determined using UV-Vis spectroscopy. It was found that the optical band gap of LCHF was 4.8 eV. The crystal functional groups were identified using FT-IR. Second harmonic generation (SHG) efficiency of the LCHF was three times higher than that of KDP. The dielectric constant, dielectric loss and AC conductivity were measured at different frequencies and temperatures.
Tahmineh Jalali, Abdolrasoul Gharaati and Mohammad Rastegar
In this paper, employing of one-dimensional magnetophotonic crystals in infrared wavelengths range is considered. For this purpose, magnetophotonic multilayer structures, composed of magnetic defect layer surrounded by dielectric and MO Bragg mirrors, have been proposed. Ce:YIG with an optical thickness in the range of 0 to λs was used as a magnetic material. By using four by four transfer matrix method, the transmittance values and Faraday rotation (FR) angles of these structures were computed. The electric field distribution was obtained by Finite Element Method (FEM). By investigation of transmittance and FR angle of magnetophotonic crystals, it was possible to design the optimized structures with a rotation larger than 30 degrees and high transmittance. Such structures with a few micrometer thickness and fast magneto-optical (MO) responses have the potential to be used in MO devices like integrated photonic elements and sensors.
Solid polymer electrolytes based on polyvinyl alcohol (PVA) doped with LiPF6 have been prepared using solution casting technique. Electrical properties of prepared electrolyte films were analyzed using AC impedance spectroscopy. The ionic conductivity was found to increase with increasing salt concentration. The maximum conductivity of 8.94 × 10−3 S·cm−1 was obtained at ambient temperature for the film containing 20 mol% of LiPF6. The conductivity enhancement was correlated to the enhancement of available charge carriers. The formation of a complex between the polymer and salt was confirmed by Fourier transform infrared spectroscopy (FT-IR). The optical nature of the polymer electrolyte films was analyzed through UV-Vis spectroscopy.
Kibrom M. Alula, James H. Resau and Osman V. Patel
Alteration in gravitational load impacts homeorhetic response in rat dams which affects neonatal pup survival. However, the effects of hypergravity (HG) exposure on the abundance of apoptosis-associated proteins in mammary epithelial cells (MECs) have not been characterized. Therefore, we examined whether chronic exposure to HG from midpregnancy alters the abundance of proapoptotic proteins in MECs during the late pregnancy and early lactation. A group of pregnant Sprague Dawley rats were exposed to either HG (2g) or normo-gravity (1g: stationary control [SC]) from days 11 to 20 of gestation (G20). Another set of animals were investigated from day 11 of pregnancy through days 1 and 3 (P1 and P3, respectively) postpartum. Quantitative (pixels [px]/lobule) immunohistochemistry at G20 of Cleaved Caspase-3 (CC-3), Tumor Protein p53 (P53), and vitamin D receptor (VDR) revealed that all the three proteins were increased (p<0.01) in HG rats compared to SC animals. At P1, the HG group had twofold higher (p<0.001) expression of CC-3 relative to the SC group. Approximately, 50% (p<0.001) more VDR was detected in the HG cohorts than SC at P3. These results suggest that a shift in g-load upregulates the expression of key proapoptotic proteins during the pregnancy-to-lactation transition in the rat MECs.
L. Chen, E.A. Selimovic, M. Daunis, T.A. Bayers T, L.J. Vargas, I.T. O’Brien, C.B. McEnroe, A.E. Kozerski, A.C. Vanhoover, W.D. Gray and J.F. Caruso
Subjects (n=13) did 30 workouts with their left leg on an Inertial Exercise Trainer (IET), while their right leg served as an untreated control. Before and after the 30 workouts, they underwent isokinetic strength tests (knee and ankle extensors of both legs) whose peak torque (PT), time to PT (TTPT), and rate of torque development (RTD) values were each analyzed with 2(leg)×2(time)×3(velocity) analysis of variances (ANOVAs), with repeated measures per independent variable. Peak force (PF) and total work (TW) data were measured from each IET workout, and they represent time course strength changes produced by our exercise intervention. PF and TW values for the three IET exercises that comprised each workout were each analyzed with one-way ANOVAs with time as the independent variable. Results included significant ankle and knee extensor PT increases, whereby the left leg achieved higher values at posttesting, but there were no significant TTPT changes and a time effect for ankle extensor RTD. Our data show that PF and TW each had significant increases over time, with the latter exhibiting greater gains over the 30-workout intervention. Our results imply that the IET yields strength gains over time comparable to standard resistive exercise hardware.
Pedro J. Llanos, Kristina Andrijauskaite, Vijay V. Duraisamy, Francisco Pastrana, Erik L. Seedhouse, Sathya Gangadharan, Leonid Bunegin and Mariel Rico
Cell Research Experiment In Microgravity (CRExIM) was launched aboard Blue Origin’s New Shepard suborbital vehicle on Tuesday, December 12, 2017, from the West Texas Launch Site in Van Horn, Texas. One of the aims of this science experiment was to assess the effects of microgravity on murine T-cells during suborbital flight. These cells were placed in a NanoLab with a data logger that sensed the acceleration, temperature, and relative humidity during preflight, flight, and postflight operations. Some discrepancies in sensor measurement were noticed, and these errors were attributed partly to the difference in sampling rates and partly to the different locations of the sensors, which made it difficult to obtain highly accurate measurements of the accelerations and to correlate both sets of data. This paper discusses the setbacks and lessons learned, which made our team find new alternatives while meeting all milestones as mandated by NanoRacks and Blue Origin. This manuscript highlights these alternatives that led to the success of the mission and gives recommendations that will enable customers to alleviate some of these challenges in future flights.
M. Mahdi, A. Djabri, M. M. Koc, R. Boukhalfa, M. Erkovan, Yu. Chumakov and F. Chemam
The full potential linearized augmented plane wave method (FLAPW) including the spin-orbit coupling has been used to study the structural, electronic and magnetic properties of GdCo5 compound. The calculations were performed within the local spin density approximation (LSDA) as well as Coulomb corrected LSDA + U approach. The study revealed that the LSDA + U method gave a better representation of the band structure, density of states and magnetic moments than LSDA. It was found that the spin magnetic moment of Co (2c) and Co (3g) atoms in the studied compound is smaller compared to the one in bulk Co. The optical and magneto-optical properties and the magneto-optical Kerr effect have also been investigated.