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排序方式: 共有114条查询结果,搜索用时 15 毫秒
1.
Davoud Dastan Seyedeh Leila Panahi Nandu B. Chaure 《Journal of Materials Science: Materials in Electronics》2016,27(12):12291-12296
A dip-coating technique was employed to prepare anatase phase of titania thin films. Fluorine doped tin oxide substrates were used to prepare titania thin films. The samples were annealed at 550 °C for 18 h. X-ray diffraction results revealed the amorphous and anatase phases of TiO2 for as-synthesized and annealed samples, respectively. The crystallite size of anatase TiO2 thin films was almost 25 nm for annealed samples. UV–visible confirmed the energy band gap 3.86 and 3.64 eV for as-prepared and calcinated titania thin films. The reduction in the energy band gap could be due to the change in crystallization and agglomeration of small grains after calcination. The morphology of the prepared films was investigated by field emission scanning electron microscopy which demonstrated the agglomeration of spherical particles of TiO2 with average particle size of about 30 nm. The molecular properties (chemical bonding) of the samples were investigated by means of Fourier Transform Infrared (FTIR) spectroscopy. FTIR analysis exhibited the formation of titania, functional group OH, hydroxyl stretching vibrations of the C–OH groups, bending vibration mode of H–O–H, alkyl C–H stretch, stretching band of Ti–OH, CN asymmetric band stretching, and C=O saturated aldehyde. 相似文献
2.
Natarajan A. Komijani A. Guan X. Babakhani A. Hajimiri A. 《Solid-State Circuits, IEEE Journal of》2006,41(12):2807-2819
Integration of mm-wave multiple-antenna systems on silicon-based processes enables complex, low-cost systems for high-frequency communication and sensing applications. In this paper, the transmitter and LO-path phase-shifting sections of the first fully integrated 77-GHz phased-array transceiver are presented. The SiGe transceiver utilizes a local LO-path phase-shifting architecture to achieve beam steering and includes four transmit and receive elements, along with the LO frequency generation and distribution circuitry. The local LO-path phase-shifting scheme enables a robust distribution network that scales well with increasing frequency and/or number of elements while providing high-resolution phase shifts. Each element of the heterodyne transmitter generates +12.5 dBm of output power at 77 GHz with a bandwidth of 2.5 GHz leading to a 4-element effective isotropic radiated power (EIRP) of 24.5 dBm. Each on-chip PA has a maximum saturated power of +17.5 dBm at 77 GHz. The phased-array performance is measured using an internal test option and achieves 12-dB peak-to-null ratio with two transmit and receive elements active 相似文献
3.
ABSTRACT In this experimental research, the silver nanoparticles were synthesized on cotton fabric using laser ablation method in the same bath. Also the effects of the size of silver nanoparticles (NPs) on the structural and antibacterial properties of silver NP-coated cotton fabric have been investigated experimentally. A pulsed laser beam was used for synthesis of Ag NPs on cotton fabric. Pulses of a Q-switched Nd:YAG laser of 1064 nm wavelengths at 7 ns pulse width and different fluencies was employed to irradiate the Ag target in deionized water in the presence of cotton fabric. Four samples were prepared using different laser fluencies. The amount, size, morphology, and structure of produced NPs were studied using their spectrum in the range of UV to IR, and scanning electron microscopy methods. Fabrics were polluted by gram-positive Staphylococcus aureus bacteria. The colony counting method was used to investigate the antibacterial activity of prepared cotton samples. Results show that laser ablation for synthesis of Ag nanoparticles on cotton fabric is an inexpensive fast method for producing antibacterial fabrics. 相似文献
4.
Nakhaei Mehrnoush Bremholm Martin Khoshnoud Davoud Sanavi 《Journal of Superconductivity and Novel Magnetism》2021,34(12):3255-3266
Journal of Superconductivity and Novel Magnetism - In this work, the RMO3 (R?=?Pr, Nd and M?=?Fe, Co) perovskites had been synthesized by hydrothermal method. The structural... 相似文献
5.
6.
The aim of this study was to analyse input–output energy and economical assessment of almond production in three age groups of orchards (group I 6–10, group II 11–15 and group III 16–20 years old) in Chahrmahal-Va-Bakhtiari province, Iran. Data for almond production were collected by administering questionnaire in face-to-face interviews from the orchards selected based on random sampling method during a 3-year period. The results showed that 57,027.13, 60,341.14 and 61,640.43 MJ ha?1 energy was consumed by group I, group II and group III, respectively. The most energy input was consumed by electricity, followed by chemical fertilizer. Energy indices were calculated, and the results revealed that energy efficiency was 0.62, 1.12 and 0.81 in the triple groups of orchards, respectively. Economical assessment showed that total production cost of almond in group I, II and III was $4547.54, $5799.26 and $5687.05 ha?1, respectively. In all orchard groups, the shares of variable and fixed production costs found to be same nearly. Net return for almond production was $14,516.22, $30,735.19 and $21,395.57ha?1, respectively. According to the research results, it was concluded that although almond production in the study region was not an efficient process in terms of energy consumption, it was a profitable agricultural operation. 相似文献
7.
Liu Lin Yang Chao Zhou Jianzhong Garmestani Hamid Dastan Davoud 《Protection of Metals and Physical Chemistry of Surfaces》2021,57(2):367-373
Protection of Metals and Physical Chemistry of Surfaces - The tribological tests of brass and steel are carried out on an in-situ tribometer. The Stribeck curve illustrates that the roughness and... 相似文献
8.
Davoud Salarbashi Mohsen Tafaghodi Omid Rajabi Bibi Sedigheh Fazli Bazzaz Vahid Soheili 《Journal of Food Safety》2023,43(1):e13024
This study aimed to produce and characterize eco-friendly SSPS nanocomposites incorporated with various concentrations of TiO2 nanoparticles (NPs) (1%, 3%, and 7%). The antimicrobial activity of the nanocomposite films against five strains of pathogenic bacteria was examined. Salmonella typhi PTCC 1609 was the most sensitive species to TiO2 NPs at concentrations equal to the synthetic antibiotic. The migration of TiO2 to ethanol and acetic acid, as two food simulants increased when the initial nano-TiO2 content increased. The release profiles for TiO2 in two simulants of ethanol and acetic acid indicated a non-Fickian release, and the release kinetics were concentration-dependent. SSPS/TiO2 nanocomposites degraded easily and thus have the potential to be applied as an eco-friendly packaging system. Oral administration of doses of 1, 12.5, 25, 50, and 75 mg/kg TiO2 revealed that the dose of 50 and 75 mg/kg increased malondialdehyde (p < .001) concentration in the liver tissue. In addition, it decreased glutathione (p < .001) concentration in the liver tissue. 相似文献
9.
The effects of titanium ion implantation on the stress corrosion cracking (SCC) behaviour of 304 austenitic stainless steel were studied. Slow strain rate tests (SSRTs) were conducted on 304 steel in air and in 5?wt-% NaCl solution. The microscopic effects of ion implantation were evaluated by Stopping and Range of Ions in Matter Procedures (SRIM). Fracture morphologies and microstructures were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The fracture surfaces illustrate that ion implantation significantly inhibits the corrosion pits that initiate SCC. A dense passive film, which inhibits SCC, was formed during the ion implantation process. SCC initiation was restrained due to the dense dislocation nets that were generated by titanium ion implantation.Highlights
Ion implantation inhibits SCC susceptibility.
The lack of Cr at the grain boundary leads to the expansion of SCC along the grain boundary.
Implantation-induced damage leads to high-density dislocations.
The surface was amorphised due to high-density dislocations.
10.
This article deals with the design of a broadband cavity‐backed microstrip‐fed wide‐slot antenna array for L‐band applications. For verification purpose, a sample 1 × 4‐element antenna array has been designed, manufactured and tested. Experimental results have shown satisfactory agreement with the simulation. The proposed antenna array exhibits a measured impedance bandwidth of 1.4 GHz (90%) with frequency of 0.85 to 2.25 GHz and the gain is higher than 11 dBi. The designed antenna has small size and low weight and can be fabricated using a low‐cost fabrication process for easy integration with RF circuits and microwave components. This work is useful for some radar applications and radio frequency identification systems. 相似文献