A Suspended Nanogap Formed by Field-Induced Atomically Sharp Tips

A sub-nanometer scale suspended gap (nanogap) defined by electric field-induced atomically sharp metallic tips is presented. A strong local electric field (\u3e109 V=m) across micro/nanomachined tips facing each other causes the metal ion migration in the form of dendrite-like growth at the cathode. The nanogap is fully isolated from the substrate eliminating growth mechanisms that involve substrate interactions. The proposed mechanism of ion transportation is verified using real-time imaging of the metal ion transportation using an in situ biasing in transmission electron microscope (TEM). The configuration of the micro/nanomachined suspended tips allows nanostructure growth of a wide variety of materials including metals, metal-oxides, and polymers. VC 2012 American Institute of Physics

Sequence Based Optimization of Manufacturing Complexity in a Mixed Model Assembly Line

Increasing production variability while maintaining operation efficiency remains a critical issue in many manufacturing industries. While the adoption of mixed-model assembly lines enables the production of high product variety, it also makes the system more complex as variety increases. This paper proposes an information entropy-based methodology that quantifies and then minimizes the complexity through product sequencing. The theory feasibility is demonstrated in a series of simulations to showcase the impact of sequencing in controlling the system predictability and complexity. Hence, the framework not only serves as a tool to quantitatively assess the impact of complexity on total system performance but also provides means and insights into how complexity can be mitigated without affecting the overall manufacturing workload

Magnetic and magnetoelastic properties of M-substituted cobalt ferrites (M=Mn, Cr, Ga, Ge)

Magnetic and magnetoelastic properties of a series of M-substituted cobalt ferrites, CoMxFe2-xO4 (M=Mn, Cr, Ga; x=0.0 to 0.8) and Ge-substituted cobalt ferrites Co1+xGexFe 2-2xO4 (x=0.0 to 0.6) have been investigated. The Curie temperature TC and hysteresis properties were found to vary with substitution content x, which indicates that exchange and anisotropy energies changed as a result of substitution of those cations for Fe. The maximum magnitude of magnetostriction decreased monotonically with increase in substitution contents x over the range x=0.0 to 0.8. However, the rate in change of magnetostriction with applied magnetic field (dlambda/dH) showed a maximum value of 5.7 x 10-9 A-1m at x=0.1 Ge sample, which is the highest value among recently reported cobalt ferrite based materials. The slope of magnetostriction with applied field dlambda/dH is one of the most important properties for stress sensor applications because it determines the sensitivity of magnetic induction to stress (dB/dsigma). The results of Ga- and Ge-substituted cobalt ferrite were compared with those of Mn- and Cr-substituted cobalt ferrites, and it was found that the effect of the substituted contents x on magnetic and magnetoelastic properties was dependent on the ionic distribution between two possible interstice sites within the spinel structure: Mn3+ and Cr3+ prefer the octahedral sites, whereas Ga3+ and Ge4+ prefer the tetrahedral sites. Temperature dependence of the absolute magnitude of the magnetic anisotropy constant |K1| of Ga-substituted cobalt ferrites CoGaxFe 2-xO4 (x=0.0 to 0.8) was investigated based on the law of approach to saturation and the results were compared with those of magnetostriction measured at the same temperatures. Based on the results, it was considered that there was a change in sign of K1 around 200 K for Ga-substituted cobalt ferrites. Comparison of the results between Ga- and Ge-substituted cobalt ferrites showed that substitution of Ge4+ ions for Fe made more pronounced effects on magnetic and magnetoelastic properties at room temperature than that of Ga3+ ions. Especially the enhanced value in dlambda/dH by Ge-substitution suggests that adjusting Ge content substituted into cobalt ferrite can be a promising route for controlling critical magnetic properties of the material for practical sensor applications

Photo-patternable and transparent films using cellulose nanofibers for stretchable origami electronics

Substantial progress in flexible or stretchable electronics over the past decade has extensively impacted various technologies such as wearable devices, displays and automotive electronics for smart cars. An important challenge is the reliability of these deformable devices under thermal stress. Different coefficients of thermal expansion (CTE) between plastic substrates and the device components, which include multiple inorganic layers of metals or ceramics, induce thermal stress in the devices during fabrication processes or long-term operations with repetitions of thermal cyclic loading-unloading, leading to device failure and reliability degradation. Here, we report an unconventional approach to form photo-patternable, transparent cellulose nanofiber (CNF) hybrid films as flexible and stretchable substrates to improve device reliability using simultaneous electrospinning and spraying. The electrospun polymeric backbones and sprayed CNF fillers enable the resulting hybrid structure to be photolithographically patternable as a negative photoresist and thermally and mechanically stable, presenting outstanding optical transparency and low CTE. We also formed stretchable origami substrates using the CNF hybrid that are composed of rigid support fixtures and elastomeric joints, exploiting the photo-patternability. A demonstration of transparent organic light-emitting diodes and touchscreen panels on the hybrid film suggests its potential for use in next-generation electronics.ope

Efficient hybrid organic-inorganic light emitting diodes with self-assembled dipole molecule deposited metal oxides

We investigate the effect of self-assembled dipole molecules (SADMs) on ZnO surface in hybrid organic-inorganic polymeric light-emitting diodes (HyPLEDs). Despite the SADM being extremely thin, the magnitude and orientation of SADM dipole moment effectively influenced the work function of the ZnO. As a consequence, the charge injection barrier between the conduction band of the ZnO and the lowest unoccupied molecular orbital of poly(9,9(')-dioctylfluorene)-co-benzothiadiazole could be efficiently controlled resulting that electron injection efficiency is remarkably enhanced. The HyPLEDs modified with a negative dipolar SADM exhibited enhanced device performances, which correspond to approximately a fourfold compared to those of unmodified HyPLEDs.open442

Staphylococcal enterotoxin sensitization in a community-based population : a potential role in adult-onset asthma

Background: Recent studies suggest that Staphylococcus aureus enterotoxin sensitization is a risk factor for asthma. However, there is a paucity of epidemiologic evidence on adult-onset asthma in community-based populations. Objective: We sought to evaluate the epidemiology and the clinical significance of staphylococcal enterotoxin sensitization in community-based adult populations. Methods: The present analyses were performed using the baseline data set of Korean adult population surveys, consisting of 1080 adults (mean age=60.2years) recruited from an urban and a rural community. Questionnaires, methacholine challenge tests, and allergen skin tests were performed for defining clinical phenotypes. Sera were analysed for total IgE and enterotoxin-specific IgE using ImmunoCAP. Results: Staphylococcal enterotoxin sensitization (0.35kU/L) had a prevalence of 27.0%. Risk factors were identified as male sex, current smoking, advanced age (61years), and inhalant allergen sensitization. Current asthma was mostly adult onset (18years old) and showed independent associations with high enterotoxin-specific IgE levels in multivariate logistic regression tests. In multivariate linear regressions, staphylococcal enterotoxin-specific IgE level was identified as the major determinant factor for total IgE level. Conclusions and Clinical Relevance: Staphylococcal enterotoxin sensitization was independently associated with adult-onset asthma in adult community populations. Strong correlations between the enterotoxin-specific IgE and total IgE levels support the clinical significance. The present findings warrant further studies for the precise roles of staphylococcal enterotoxin sensitization in the asthma pathogenesis

Hybrid organic-inorganic light-emitting electrochemical cells using fluorescent polymer and ionic liquid blend as an active layer

We demonstrate enhanced device performance by using a blend of emissive polymer and mobile ionic liquid molecules in hybrid organic-inorganic polymeric light-emitting electrochemical cells with high air stability. The mobile anions and cations redistributed near each electrode/active layer interface make ohmic contacts, thereby enhancing current density and electroluminescence efficiency at relatively low operating voltage.open12

Vasopressor Bolus Effects on Dynamic Arterial Elastance (EaDyn) and Contractility (dP/dt)

The Hypotension Prediction Index is a machine learning derived algorithm that predicts intraoperative hypotension. The algorithm provides two additional hemodynamic parameters, EaDyn and dP/dt, that characterize the physiological changes and may provide guidance regarding the most efficacious treatments. dP/dt correlates with ventricular contractility from peripheral artery waveforms. EaDyn (dynamic arterial elastance) is the ratio of pulse pressure variation and stroke volume variation (PPV/SVV), correlating with peripheral vascular resistance

BIM-Based Construction Information Management Framework for Site Information Management

Projects in the construction industry are becoming increasingly large and complex, with construction technologies, methods, and the like developing rapidly. Various different types of information are generated by construction projects. Especially, a construction phase requires the input of many resources and generates a diverse set of information. While a variety of IT techniques are being deployed for information management during the construction phase, measures to create databases of such information and to link these various different types of information together are still insufficient. As such, this study aims to suggest a construction information database system based on BIM technology to enable the comprehensive management of site information generated during the construction phase. This study analyzed the information generated from construction sites and proposed a categorization system for structuring the generated information, along with a database model for storing such structured information. Through such efforts, it was confirmed that such a database system can be used for accumulating and using construction information; it is believed that, in the future, the continual accumulation and management of construction information will allow for corporate-level accumulation of knowledge as opposed to the individual accumulation of know-how