Oxidation of sputtered Zr thin film on Si substrate

Oxidation of sputtered Zr thin film on Si substrate has been investigated by varying oxidation times (5–60 min) at 500 °C. Fourier transform infrared spectroscopy indicated the existence of ZrO₂ by showing spectra of Zr–O. Vibration mode of Si–O and Zr–O–Si are also detected for all samples oxidized at different duration. This suggested the existence of SiO _x and Zr _x Si _y O _z compounds and they might be located at interfacial layers (ILs) between ZrO₂ and Si. Cross-sectional image of high resolution transmission electron microscopy taken from 60-min oxidized sample showed that both ZrO₂ and IL thickness is ~3.5 nm. Time-of-flight secondary-ion-mass spectroscopy suggested that Zr _x Si _y O _z may be formed after oxidized for 15 min. The proposed IL is consisted of a mixture of Zr _x Si _y O _z and SiO _x . A physical model has been established to explain the observation. Electrical characterization shows that capacitance–voltage curves have small hysteresis and their flatband voltages are shifted to a negative bias. Effective dielectric constant values of the investigated oxides are in the range of 4.22–5.29. Leakage current density–breakdown voltage characteristic shows that 5-min oxidized sample has the lowest dielectric breakdown voltage if compared with the other samples.     

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ACSAC (Asia-Pacific Computer Systems Architecture) is a premium forum for researchers, educators and practitioners to come to the Asia-Pacific region to exchange the ideas about the latest developments in Computer Systems Architecture, ACSAC'04 was held in Beijing during September 7-9 2004. Out of 152 submissions, a total of 45 papers were accepted and presented at this annual conference. We are pleased to have co-chaired this conference, which received the largest number of submissions in the conference history. Our plan for organising a special issue for ACSAC'04 was mentioned earlier in its CFP. In September 20 2004,     

Basis of pulmonary toxicity associated with cationic lipid-mediated gene transfer to the mammalian lung

Studies have indicated that although abundant levels of transgene expression could be achieved in the lungs of mice instilled with cationic lipid:pDNA complexes, the efficiency of gene transfer is low. As a consequence, a relatively large amount of the complex will need to be administered to the human lungs to achieve therapeutic efficacy for indications such as cystic fibrosis. Because all cationic lipids exhibit some level of cytotoxicity in vitro, we assessed the safety profile of one such cationic lipid, GL-67, following administration into the lungs of BALB/c mice. Dose-dependent pulmonary inflammation was observed that was characterized by infiltrates of neutrophils, and, to a lesser extent, macrophages and lymphocytes. The lesions in the lung were multifocal in nature and were manifested primarily at the junction of the terminal bronchioles and alveolar ducts. The degree of inflammation abated with time and there were no apparent permanent fibrotic lesions, even in animals that were treated at the highest doses. Analysis of the individual components of the complex revealed that the pulmonary inflammation was primarily cationic lipid-mediated with a minor contribution from the neutral co-lipid DOPE. Associated with the lesions in the lungs were elevated levels of the pro-inflammatory cytokines interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), and interferon-gamma (IFN-gamma) that peaked at days 1-2 post-instillation but resolved to normal limits by day 14. Total cell counts, primarily of neutrophils, were also significantly elevated in the bronchoalveolar lavage fluids of GL-67:pDNA-treated mice between days 1 and 3 but returned to normal limits by day 14. No specific immune responses were detected against the cationic lipid or plasmid DNA in mice that had been either instilled or immunized with the individual components or complex, nor was there any evidence of complement activation. These studies indicate that a significant improvement in the potency of cationic lipid:pDNA formulations is desirable to minimize the toxicity associated with cationic lipids.     

Influence of post-deposition annealing in oxygen ambient on metal–organic decomposed CeO2 film spin coated on 4H-SiC

Post-deposition annealing (PDA) was performed in oxygen ambient at different temperatures (600, 800, 1,000 and 1,150 °C) onto metal–organic decomposition (MOD) prepared CeO₂ film spin coated on n-type 4H-SiC substrate. Effects of PDA onto the physical and electrical characteristics of MOD-derived CeO₂ were investigated. Four orientations [(111), (200), (220), and (311)] of CeO₂ peaks were revealed by X-ray diffraction analysis in all of the samples with a preferred orientation in (200) direction. However, α-Ce₂O₃ and cerium silicate (Ce₂Si₂O₇) interfacial layers emerged at 1,150 °C. As annealing temperature increased, grain size of films was increased but microstrains were decreased. Electrical results indicated that negative effective oxide charge and slow trap density were decreased as temperature increased. The lowest interface trap density was perceived by sample annealed at 1,000 °C. However, the highest electric field was obtained by sample annealed at 1,150 °C. Reasons that contributed to this observation were discussed.     

Effects of the shape of the energy director on far‐field ultrasonic welding of thermoplastics

An energy director is widely used in ultrasonic welding to increase the welding speed and quality. In the present work, three different types of energy directors were studied—namely, a triangular, a rectangular, and an innovative semicircular energy director. Experiments were performed using far‐field test samples made of amorphous‐type (ABS) and semicrystalline‐type (PE) thermoplastics. It was found that the weld time is an important parameter of ultrasonic welding for the three types of energy directors studied. Weld pressure has different effects for the types of plastics tested. Increasing the weld pressure will decrease the welding efficiency for ABS. But for PE, increasing the weld pressure to four bars will increase the welding efficiency. The shape of the energy director was found to significantly affect the welding efficiency. In comparison, a semicircular shape was found to yield the highest welding efficiency under the same welding conditions and the triangular shape the lowest. Temperature measurements at the triangular energy director during the welding process indicate that the energy director absorbed 48.5% of the welding energy for ABS and 21.1% for PE. The different energy absorption rates are probably due to the difference in elasticity and viscosity between amorphous (ABS) and semicrystalline (PE) plastics.     

Effect of Attritor Milling on Synthesis and Sintering of Forsterite Ceramics

Forsterite (Mg₂SiO₄) was chosen as a new candidate for bone implant application because of its superior fracture toughness and good bioactivity. However, synthesizing pure forsterite has been a challenge to many researchers because of its inability to eliminate secondary phases that have similar chemical compounds as forsterite. Attritor mill was introduced to form pure forsterite via solid‐state method through the reaction between magnesium carbonate (MgCO₃) and talc (Mg₃Si₄(OH)₂). Attritor‐milled samples showed superior mechanical properties compared with ball‐milled samples because of the smaller particle size of the former which in turn eliminated the secondary phases at low sintering temperature.     

Comparison of oxidized/nitrided Zr thin films on Si and SiC substrates

This work utilizes simultaneous thermal oxidation and nitridation technique to transform sputtered Zr to ZrO₂ and to Zr-oxynitride thin films on Si and SiC substrates, respectively, in nitrous oxide gas ambient. Various characterization techniques such as X-ray photoelectron spectroscopy, energy-filtered transmission electron spectroscopy, atomic force microscopy, X-ray diffraction, capacitance–voltage measurements, and leakage current density-electric field measurements were carried out to evaluate and compare the structural, chemical, and electrical properties of the films produced on both Si and SiC substrates.     

Sustainable approach to biotransform industrial sludge into organic fertilizer via vermicomposting: a mini‐review

Currently, industrial sludge is generated in large amounts. Industrial sludge is a solid or semi‐solid material consisting of all compounds removed from wastewater, as well as any substances added to the biological and chemical operation units during the treatment process. The composition of sludge may vary considerably. Furthermore, distinctive treatment and disposal methods are necessary as sludge produced from different industries has different characteristics. Therefore, processing and disposing of industrial sludge is a challenging and complex environmental problem. Landfilling, incineration and agricultural land application are the three most commonly employed methods for the disposal of industrial sludge. Among the three methods, the agricultural land application is a convenient and economical disposal alternative for industrial sludge. However, industrial sludge could have high putrescible content and pathogenic hazards. One possible way to ensure that the industrial sludge could be reused on agricultural land is by conditioning and stabilizing the sludge using a pretreatment process. One of the pretreatment processes which could be employed in this context is vermicomposting. Vermicomposting is an alternative for biological stabilization of organic wastes, with the addition of earthworms. Through vermicomposting, industrial sludge could be transformed into matured organic fertilizer or vermicompost in a shorter period. Thus, this work reviewed the recent literature on utilizing the vermicomposting process to manage industrial sludge in order to assess the feasibility of this technology. The present review also provides a brief overview of the production and treatment methods of industrial sludge. © 2017 Society of Chemical Industry     

Effects of O2 and N2 Gas Concentration on the Formation of Ho2O3 Gate Oxide on 4H-SiC Substrate

Silicon - In this paper, the impacts of flow concentration of oxynitridation on the structural and electrical performance of a high-κ Ho2O3 dielectric on n-type 4H-SiC were studied. The Ho2O3...     

Investigation of honey as the electrolyte gate dielectrics of field effect transistors

The paper reports on the investigation of honey as the electrolyte gate dielectrics of graphene field effect transistors. Transfer and output characteristics of graphene transistors were collected at room temperature and 40 °C under open air. Typical behaviors such as Dirac neutrality point and linear relation of drain current with drain-source voltage at low field and various gate bias voltages were achieved. In addition, cleaning and reapplication of honey on transistors only show slight changes in those characteristics.