Fabrication and electrical characteristics of high-performance ZnO nanorod field-effect transistors

We report on fabrication and electrical characteristics of high-mobility field-effect transistors (FETs) using ZnO nanorods. For FET fabrications, single-crystal ZnO nanorods were prepared using catalyst-free metalorganic vapor phase epitaxy. Although typical ZnO nanorod FETs exhibited good electrical characteristics, with a transconductance of similar to140 nS and a mobility of 75 cm(2)/V s, the device characteristics were significantly improved by coating a polyimide thin layer on the nanorod surface, exhibiting a large turn-ON/OFF ratio of 10(4)-10(5), a high transconductance of 1.9 muS, and high electron mobility above 1000 cm(2)/V s. The role of the polymer coating in the enhancement of the devices is also discussed. (C) 2004 American Institute of Physics.X11333sciescopu

Lowering the Number of False Positive Responses to Electric Pulp Tests by Qualifying Patient Response

The electric pulp test (EPT) has been shown to be a valuable tool in assessing pulp vitality. One of its drawbacks, however, is its high number of false positives. The purpose of this study was to determine if qualifying the type of sensation elicited by the test could lower the percentage of false positive responses. A retrospective chart review of an eleven-month period was conducted, examining all patients with necrotic teeth tested with the EPT. Of 189 teeth, when the patient responded to EPT at first sensation 23.3% of teeth were incorrectly identified as vital. When the patient was asked to respond only if they felt an uncomfortable sensation, the false positive rate was lowered to 8.5%, a statistically significant difference. No association was found between the teeth reclassified as necrotic and age, gender, type of tooth, or number of canals

Reliable current changes with selectivity ratio above 10(9) observed in lightly doped zinc oxide films

Low-power operation of semiconductor devices is crucial for energy conservation. In particular, energy-efficient devices are essential in portable electronic devices to allow for extended use with a limited power supply. However, unnecessary currents always exist in semiconductor devices, even when the device is in its off state. To solve this problem, it is necessary to use switch devices that can turn active devices on and off effectively. For this purpose, high on/off current selectivity with ultra-low off-current and high on-current is required. Here, we report a novel switch behavior with over 10(9) selectivity, a high on-current density of 1 MA cm(-2), an ultra-low off-current density of 1 mA cm(-2), excellent thermal stability up to 250 degrees C and abrupt turn-on with 5 mV per decade in solution-processed silver-doped zinc oxide thin films. The selection behavior is attributed to light doping of silver ions in zinc oxide films during electrochemical deposition to generate atomic-scale narrow conduction paths, which can be formed and ruptured at low voltages. Device simulation showed that the new selector devices may be used in ultra-high-density memory devices to provide excellent operation margins and extremely low power consumption.1110Ysciescopu

Precise control of phase transformation process in lead zirconate titanate thin films by focused line-beam scanning

Phase transformation and grain growth processes of lead zirconate titanate (PZT) thin films have been precisely controlled by using focused line-beam scanning. The authors promoted the lateral crystallization of PZT grains by controlling a nucleation process and increasing the size of single grains to be as large as 40 μm in length. Focused line-beam scanning allows for the selective growth and crystallization of large PZT grains on predetermined nucleation sites. The high growth rate of the selected PZT grains was attributed to successive suppression of undesirable nucleation except at predetermined positions when pretreated PZT films were exposed to the focused line beam. © 2007 American Institute of Physics

Hybrid Organic-Inorganic Perovskite Memory with Long-Term Stability in Air

11142Ysciescopu

Fairness perceptions of income-based educational inequality: The impact of social class and ideological orientations

Income-based educational inequality is a global issue. In Australia, schools in the relatively large private sector charge a range of fees, with public schools also exhibiting considerable income differences. Using a nationally representative sample in the Australian Survey of Social Attitudes, we examined the public's fairness perceptions of income-based educational inequality and how their fairness perceptions are related to self-interest (particularly regarding social class) and ideological orientations. We found that people hold diverse views about the fairness of income-based educational inequality and that the number of people who perceived it as unfair was almost double the number of those who perceived it as fair. Respondents categorised as upper/upper-middle-class were, however, more likely to perceive income-based educational inequality as fair, while agreement with government responsibility for economic well-being was associated with a negative view of income-based educational inequality. Implications of these findings for the promotion of socially just and equitable education are discussed

Carers of People with Mental Illness from Culturally and Linguistically Diverse Communities

Australia is a multicultural country and it is common for families from culturally and linguistically diverse (CALD) communities to care for their relatives with mental illness. However, there are limited Australian studies examining the experiences of informal carers of people with mental illness from CALD communities. A scoping review was conducted to search for peer-reviewed articles reporting the perception of carers regarding their caregiving experiences, wellbeing, and needs. Using cultural responsiveness as a conceptual framework, this study analysed the findings of the identified studies to generate themes. Findings show that carers experience severe caregiving challenges and face considerably poor culturally oriented services in mental health. Social work implications concerning the need to provide culturally responsive practice in mental health services are discussed

Effect of halide-mixing on the switching behaviors of organic-inorganic hybrid perovskite memory

Mixed halide perovskite materials are actively researched for solar cells with high efficiency. Their hysteresis which originates from the movement of defects make perovskite a candidate for resistive switching memory devices. We demonstrate the resistive switching device based on mixed-halide organic-inorganic hybrid perovskite CH3NH3PbI3−xBrx (x = 0, 1, 2, 3). Solvent engineering is used to deposit the homogeneous CH3NH3PbI3−xBrx layer on the indium-tin oxide-coated glass substrates. The memory device based on CH3NH3PbI3−xBrx exhibits write endurance and long retention, which indicate reproducible and reliable memory properties. According to the increase in Br contents in CH3NH3PbI3−xBrx the set electric field required to make the device from low resistance state to high resistance state decreases. This result is in accord with the theoretical calculation of migration barriers, that is the barrier to ionic migration in perovskites is found to be lower for Br− (0.23 eV) than for I− (0.29–0.30 eV). The resistive switching may be the result of halide vacancy defects and formation of conductive filaments under electric field in the mixed perovskite layer. It is observed that enhancement in operating voltage can be achieved by controlling the halide contents in the film.1119Ysciescopu

Photoluminescent characteristics of Ni-catalyzed GaN nanowires

The authors report on time-integrated and time-resolved photoluminescence (PL) of GaN nanowires grown by the Ni-catalyst-assisted vapor-liquid-solid method. From PL spectra of Ni-catalyzed GaN nanowires at 10 K, several PL peaks were observed at 3.472, 3.437, and 3.266 eV, respectively. PL peaks at 3.472 and 3.266 eV are attributed to neutral-donor-bound excitons and donor-acceptor pair, respectively. Furthermore, according to the results from temperature-dependent and time-resolved PL measurements, the origin of the PL peak at 3.437 eV is also discussed. (c) 2006 American Institute of Physics.X1147sciescopu

Dietary patterns, insulin sensitivity and inflammation in older adults.

Background/objectivesSeveral studies have linked dietary patterns to insulin sensitivity and systemic inflammation, which affect risk of multiple chronic diseases. The purpose of this study was to investigate the dietary patterns of a cohort of older adults, and to examine relationships of dietary patterns with markers of insulin sensitivity and systemic inflammation.Subjects/methodsThe Health, Aging and Body Composition (Health ABC) Study is a prospective cohort study of 3075 older adults. In Health ABC, multiple indicators of glucose metabolism and systemic inflammation were assessed. Food intake was estimated with a modified Block food frequency questionnaire. In this study, dietary patterns of 1751 participants with complete data were derived by cluster analysis.ResultsSix clusters were identified, including a 'healthy foods' cluster, characterized by higher intake of low-fat dairy products, fruit, whole grains, poultry, fish and vegetables. In the main analysis, the 'healthy foods' cluster had significantly lower fasting insulin and homeostasis model assessment of insulin resistance values than the 'breakfast cereal' and 'high-fat dairy products' clusters, and lower fasting glucose than the 'high-fat dairy products' cluster (P≤0.05). No differences were found in 2-h glucose. With respect to inflammation, the 'healthy foods' cluster had lower interleukin-6 than the 'sweets and desserts' and 'high-fat dairy products' clusters, and no differences were seen in C-reactive protein or tumor necrosis factor-α.ConclusionsA dietary pattern high in low-fat dairy products, fruit, whole grains, poultry, fish and vegetables may be associated with greater insulin sensitivity and lower systemic inflammation in older adults