The effect of film thickness and doping content of SnO2:F thin films prepared by ultrasonic spray method

This paper reports on the effects of film thickness and doping content on the optical and electrical properties of fluorine-doped tin oxide. Tin (II) chloride dehydrate, ammonium fluoride dehydrate, ethanol and HCl were used as the starting materials, dopant source, solvent and stabilizer, respectively. The doped films were deposited on a glass substrate at different concentrations varying between 0 and 5 wt% using an ultrasonic spray technique. The SnO₂:F thin films were deposited at a 350 ℃ pending time (5, 15, 60 and 90 s). The average transmission was about 80%, and the films were thus transparent in the visible region. The optical energy gap of the doped films with 2.5 wt% F was found to increase from 3.47 to 3.89 eV with increasing film thickness, and increased after doping at 5 wt%. The decrease in the Urbach energy of the SnO₂:F thin films indicated a decrease in the defects. The increase in the electrical conductivity of the films reached maximum values of 278.9 and 281.9 (Ω·cm^-1) for 2.5 and 5 wt% F, respectively, indicating that the films exhibited an n-type semiconducting nature. A systematic study on the influence of film thickness and doping content on the properties of SnO₂:F thin films deposited by ultrasonic spray was reported.     

Corrosion Inhibition of Mild Steel in Hydrochloric and Nitric Acid Solutions Using Willow Leaf Extract

Protection of Metals and Physical Chemistry of Surfaces - The inhibition mechanism of willow (Salix) plant leaf extract on the corrosion of mild steel in 0.5 M HCl and 0.5 M HNO3 solutions...     

Optimization of Bulk Thermoelectrics: Influence of Cu Insertion in Ag3.6Mo9Se11

Currently, there is a resurgence of interest in thermoelectric materials with enhanced efficiency. Among investigated classes of bulk thermoelectrics such as partially filled skutterudites, Zn₄Sb₃-based materials, and clathrates, novel polycrystalline Mo₉ cluster-based chalcogenides were reported recently. Among those, Chevrel phase-derived Ag _y Mo₉Se₁₁ (with 3.4????y????3.9) compounds have shown interesting thermoelectric properties, in particular extremely low thermal conductivity allowing improved thermoelectric efficiency compared with reported Chevrel phases. They also possess a complex crystallographic structure where stacked Mo₉Se₁₁ units leave channels occupied by Ag atoms. Analysis of the structural determinants of the thermoelectric properties of Ag _y Mo₉Se₁₁ suggested that performance improvements could result from further Cu insertion. In this paper, we describe the synthesis route we used for preparing quaternary Ag-Cu-Mo-Se compositions by a combination of powder metallurgy and spark plasma sintering techniques. Characterization by x-ray diffraction, scanning electron microscopy, and electrical and thermal measurements has been performed. The results obtained for two compounds (Ag_3.6Cu_0.2Mo₉Se₁₁ and Ag_3.6Cu_0.4Mo₉Se₁₁) are discussed and compared with those of the parent ternary compound Ag_3.6Mo₉Se₁₁.     

Prediction study of the structural, elastic and electronic properties of ANSr3 (A = As, Sb and Bi)

Based on first-principles total energy calculations, we predict the elastic and electronic properties of the anti-perovskites AsNSr₃, SbNSr₃ and BiNSr₃ compounds. The calculated lattice constants are in good agreement with the available results. The independent elastic constants (C₁₁, C₁₂ and C₄₄) and their pressure dependence are calculated using the static finite strain technique. The isotropic elastic moduli, namely, bulk modulus (B), shear modulus (G), Young’s modulus (E), Poisson’s ratio (σ) and Lame’s constants (λ and μ) are calculated in framework of the Voigt–Reuss–Hill approximation for ideal polycrystalline ANSr₃ aggregates. By analysing the ratio between the bulk and shear moduli, we conclude that ANSr₃ compounds are brittle in nature. We estimated the Debye temperature of ANSr₃ from the average sound velocity. The band structures show that all studied materials are semiconductors. The analysis of the site and momentum projected densities, charge transfer and charge densities show that bonding is of covalent–ionic nature. This is the first quantitative theoretical prediction of the elastic and electronic properties of AsNSr₃, SbNSr₃ and BiNSr₃ compounds that requires experimental confirmation.     

Final report of a phase II study of chemotherapy with bleomycin, epirubicin, and cisplatin for locally advanced and metastatic/recurrent undifferentiated carcinoma of the nasopharyngeal type

PURPOSE: This article presents an assessment of the combination of bleomycin, epirubicin, and cisplatin as induction chemotherapy before radiotherapy in the treatment of undifferentiated carcinoma of the nasopharyngeal type in patients with recurrent/metastatic disease (group A), and in previously untreated patients with locoregionally advanced disease (UICC-AJCC 87, N2-3, M0) (group B) in terms of toxicity, antitumoral activity, and therapeutic efficacy. PATIENTS AND METHODS: From January 1987 to September 1990, 111 consecutive patients with histologically proven UCNT were treated with six cycles of intravenous cisplatin (100 mg/m2 day 1) epirubicin (80 mg/m2 day 1), and bleomycin (15 mg bolus day 1), followed by 16 mg/m2/day continuous infusion for 5 days, repeated every 21 days for three cycles. Three further cycles without bleomycin were given to 44 patients in group A. In group B (67 patients), only three cycles of the same protocol were given, with a slightly lower dose of epirubicin (70 mg/m2), followed by conventional radiotherapy (70 Gy/7 weeks). RESULTS: Of 44 patients entered in group A, 38 were evaluable for response. We observed 9 (20%) complete responses and 11 (25%) partial responses, for a 45% overall response rate. In 12 patients not previously given chemotherapy, there were 4 complete responses, compared to 5 complete responses in 32 patients previously treated with chemotherapy. Four patients are alive with no evidence of disease after 53+, 60+, 61+, and 72+ months. In group B the overall response rate to chemotherapy was 98% with 42 complete (62%) and 24 partial responses (36%). Three months after the end of radiotherapy, the overall complete response rate was 94% (63 patients). After a median follow-up time of 77 months (range, 53-94), the 4-year overall survival and disease-free survival rates for this group are 66% and 60%, respectively. The median disease-free survival has not been reached at 90 months. CONCLUSION: The results of the BEC combination trial are very encouraging in metastatic and recurrrent UCNT, with durable remissions in this poor-prognosis population. The results in patients with locally advanced disease have motivated prospective phase III testing of the neoadjuvant chemotherapy approach to evaluate its impact on locoregionally advanced disease (> or =N2MO UICC-AJCC 87).     

Influence of Low Cd-Doping Concentration (0.5 and 3 wt.%) and Different Substrate Types (Glass and Silicon) on the Properties of Dip-Coated Nanostructured ZnO Semiconductors Thin Films

Journal of Inorganic and Organometallic Polymers and Materials - The investigation of semiconductor films of undoped ZnO and doped with two weight percentages of Cadmium (0.5 and 3) were grown on...     

A Step-Down Technique to Calibrate AC Current Down to 10?μA Using a Precision 10?mA Current Shunt

This paper describes a calibration procedure for AC current measurements at 1?mA, 100 ??A and 10???A using a NIST-calibrated 10?mA current shunt as a reference standard. The procedure involves a step-down technique using the reference transfer standards (RTS) as a precision current divider. The RTS is used at values of 370???, 3.3 and 30?k?? to provide the intended currents. Uncertainty calculations are estimated for calibrating the AC current of 10?mA, 1?mA, 100 ??A and 10???A at 55?Hz and 1?kHz. The expanded uncertainties are around the values of 37 nA and 1?nA for the ranges of 1?mA?C10???A respectively.     

Tests on reinforced concrete beams strengthened in shear using near surface mounted CFRP and steel bars

This paper presents the experimental results obtained from testing four large scale reinforced concrete T-beams strengthened in shear using near surface mounted (NSM) carbon fiber reinforced polymer (CFRP) bars and conventional steel reinforcing bars. The experimental program studied the effects of the orientation of the NSM bars, their type and their anchorage into the flange concrete. The tests showed that the NSM bars were engaged in the resistance as soon as they were crossed by a crack. The strengthening increased the shear capacity by 37%-92%, reduced the width of the diagonal cracks and allowed the beams to develop significant flexural ductility. The results also showed that orienting the NSM bars at 45° and extending their anchorage into the flange concrete improved the efficiency of strengthening. The CFRP strengthened test regions achieved 7%-10% larger shear capacity than the steel strengthened test regions, and their behavior was relatively similar.