The influence of temperature on deformation-induced martensitic transformation in 301 stainless steel

Deformation-induced martensitic transformations are increasingly being used to create desirable mechanical properties in steels. Here, the kinetics of the deformation-induced martensitic transformation is investigated at 300, 263, 223, 173 and 100 K using in situ neutron diffraction during tensile loading. The results from these experiments show a distinct change in the transformation behaviour between 300 K and the tests conducted at 263 K and below, causing a difference in martensite structure. The difference in transformation kinetics is correlated to the suppression of slip at low temperatures, as evidenced using diffraction peak intensity analysis for different grain families and corroborated using transmission electron microscopy. A direct correlation between the deformation-induced martensite fraction and the work-hardening rate is shown.     

Optically‐Pumped Lasing in Hybrid Organic–Inorganic Light‐Emitting Diodes

Here, the use of metal oxide layers both for charge transport and injection into an emissive semiconducting polymer and also for the control of the in‐plane waveguided optical modes in light‐emitting diodes (LEDs) is reported. The high refractive index of zinc oxide is used to confine these modes away from the absorbing electrodes, and include a nano‐imprinted grating in the polymer layer to introduce distributed feedback and enhance optical out‐coupling. These structures show a large increase in the luminescence efficiency over conventional devices, with photoluminescence efficiency increased by up to 45%. Furthermore, optically‐pumped lasing in hybrid oxide polymer LEDs is demonstrated. A tuneable lasing emission is also obtained in a single device structure by employing a graduated thickness of a zinc oxide inter‐layer. This demonstrates the scope for using such architectures to improve the external efficiency of organic semiconductor LEDs, and opens new possibilities for the realization of polymer injection lasers.     

A clinical and cytogenetic study of Turner syndrome

Forty five case of Turner syndrome diagnosed in the Genetics Clinic, between January 1986 and December 1993, were analyzed. The most commonly observed karyotype was 45, X (44.4%), followed by 45, X/46, XX mosaicism (24.4%). Less frequently demonstrated karyotypes were 45, X/46, X, i (Xq) mosaicism and 46, X, i (Xq) (13.3%). Mosaicism for chromosome was seen in 6.7% of patients. Patients with 45, X karyotype had short stature (85%), dysmorphic facies (60%), delayed appearance of secondary sexual characters (100%) and primary amennorhea (100%). Those with 45, X/46, XX mosaicism were less often dysmorphic and presented with either primary or secondary amenorrhea. Patients with 45, X karyotype were younger at diagnosis and had a significantly shorter mean adult height than those with 45, X/46, XX mosaicism. The phenotype in patients with other karyotypic abnormalities was similar to the 45, X group. Short stature and primary or secondary amenorrhea occurring together in a female strongly suggests the possibility of Turner syndrome, which should be confirmed by chromosomal analysis.     

Photocurrent imaging of phase segregation in a ternary polymer blend induced via a non-solvent route

Control of phase separation length scales of polymers in a solution-processed film of binary (two-component) polymer blends is the most important step to realize significant photocharge generation and transport efficiencies leading to efficient solar cells. The dynamics of phase segregation becomes more complex in ternary (three-component) polymer blends. In the three-component blend, one component serves as sensitizer, and other two act as donor and acceptor polymer. The sensitizer absorbs photons and the energy is quickly transferred to the host donor. Subsequently, efficient charge transfer occurs at the host donor/acceptor interface. Depending on the relative amount of phase segregation between sensitizer/donor, sensitizer/acceptor and donor/acceptor, the different photophysical mechanisms (viz. energy transfer and charge transfer) are either boosted or suppressed. The correct kind of morphology should allow efficient energy transfer at the sensitizer/donor interface followed by efficient charge transfer at the donor/acceptor interface. We attempt to address these requirements by modulating the nanomorphology of a ternary blend via tailoring the non-solvent concentration in the ternary polymer blend solution. Here, we study the effect of non-solvent mixing and resultant film morphology is characterized by wide-field local photocurrent imaging and photoluminescence imaging in a confocal microscope set-up.     

Adaptive learning architecture-based predistorter for nonlinear VLC system

Photonic Network Communications - A light-emitting diode (LED) acts as a transmitter in a visible-light communication (VLC) system. However, the nonlinear characteristics of LED limit the...     

Quantitative Correlation of Perovskite Film Morphology to Light Emitting Diodes Efficiency Parameters

This paper reports quantitative correlation of CH₃NH₃PbBr₃ (MAPbBr₃) thin film morphology to light emitting diode efficiency parameters. Sequential (spin coating) deposition is used for highly reproducible and dense film morphology of MAPbBr₃ thin‐film. In this fabrication process using an orthogonal solvent approach, control of morphology, coverage, thickness, and optical properties in these compact thin‐films is demonstrated. Optical studies show direct correlation between morphology to dynamics of photoluminescence (PL) and absolute PL yield. Perovskite light emitting diodes (PeLEDs) are fabricated from these films to find the best ratio of PbBr₂ versus MABr for optimal performance. This study demonstrates PeLEDs with high brightness, ≈1050 cd m^?2 at 4.7 V (luminance efficiency ≈0.1 cd A^?1), for optimal thin‐film process with state‐of‐the‐art device performance. This quantitative analysis suggests that these state‐of‐the‐art PeLEDs suffer from poor charge carrier balance (≈2%) and out‐coupling efficiency (≈6%). Interestingly, charge carrier balance and PL yield together can explain the change in PeLED efficiency modulation with film morphology. Studies on single carrier devices show that these PeLEDs are electron current dominated and charge carrier balance increases with operating bias voltage.     

Solar photocatalytic removal of Cu(II), Ni(II), Zn(II) and Pb(II): speciation modeling of metal-citric acid complexes

The present study is targeted on solar photocatalytic removal of metal ions from wastewater. Photoreductive deposition and dark adsorption of metal ions Cu(II), Ni(II), Pb(II) and Zn(II), using solar energy irradiated TiO2, has been investigated. Citric acid has been used as a hole scavenger. Modeling of metal species has been performed and speciation is used as a tool for discussing the photodeposition trends. Ninety-seven percent reductive deposition was obtained for copper. The deposition values of other metals were significantly low [nickel (36.4%), zinc (22.2%) and lead (41.4%)], indicating that the photocatalytic treatment process, using solar energy, was more suitable for wastewater containing Cu(II) ions. In absence of citric acid, the decreasing order deposition was Cu(II)>Ni(II)>Pb(II)>Zn(II), which proves the theoretical thermodynamic predictions about the metals.     

Barium Hydroxide as an Interlayer Between Zinc Oxide and a Luminescent Conjugated Polymer for Light‐Emitting Diodes

A study of hybrid light‐emitting diodes (HyLEDs) fabricated with and without solution‐processible Cs₂CO₃ and Ba(OH)₂ inorganic interlayers is presented. The interlayers are deposited between a zinc oxide electron‐injection layer and a fluorescent emissive polymer poly(9‐dioctyl fluorine–alt‐benzothiadiazole) (F8BT) layer, with a thermally evaporated MoO₃/Au layer used as top anode contact. In comparison to Cs₂CO₃, the Ba(OH)₂ interlayer shows improved charge carrier balance in bipolar devices and reduced exciton quenching in photoluminance studies at the ZnO/Ba(OH)₂/F8BT interface compared to the Cs₂CO₃ interlayer. A luminance efficiency of ≈28 cd A^?1 (external quantum efficiency (EQE) ≈ 9%) is achieved for ≈1.2 μm thick single F8BT layer based HyLEDs. Enhanced out‐coupling with the aid of a hemispherical lens allows further efficiency improvement by a factor of 1.7, increasing the luminance efficiency to ≈47cd A^?1, corresponding to an EQE of 15%. The photovoltaic response of these structures is also studied to gain an insight into the effects of interfacial properties on the photoinduced charge generation and back‐recombination, which reveal that Ba(OH)₂ acts as better hole blocking layer than the Cs₂CO₃ interlayer.     

High-pressure liquid-chromatographic determination of 5-(4-hydroxyphenyl)-5-phenylhydantoin in humanurine

We describe a sensitive and precise high-pressure liquid-chromatographic method for measurement of total 5-(4-hydroxyphenyl)-5-phenylhydantoin, a metabolite of phenytoin, in urine. An aliquot of urine, containing 5-(4-methylphenyl)-5-phenylhydantoin as an internal standard, is processed and chromatographed. The metabolite and internal standard are identified from their retention times and quantitated from their relative response factors. The metabolite is separated from normal urine constituents and internal standard in less than 8 min. The sensitivity of the method is such that after the usual dose it can be measured in 0.5 ml of urine; the lower limit of detection is 300 ng.     

Combined artificial bee colony algorithm and machine learning techniques for prediction of online consumer repurchase intention

Transactions through the web are now a progressive mechanism to access an ever-increasing range of services over more and more diverse environments. The internet provides many opportunities for companies to provide personalized online services to their customers, but the quality and novelty of some web services may adversely affect the appeal and user gratification. In the future, prediction of the consumer intention needs to be a main focus for selecting the web services for an application. The aim of this study is to predict online consumer repurchase intentions; to accomplish this objective a hybrid approach is chosen with a combination of machine learning techniques and artificial bee colony (ABC) algorithm being used. The study starts with identification of consumer characteristics for repurchase intention, followed by determining the feature selection of consumer characteristics and shopping mall attributes (with >0.1 threshold value) for the prediction model using ABC. Finally, validation using k-fold cross has been employed to measure the best classification model robustness. The classification models, viz. decision trees (C5.0), AdaBoost, random forest, support vector machine and neural network, are utilized to predict consumer purchase intention. Performance evaluation of identified models on training–testing partitions (70–30%) of the data set shows that the AdaBoost method outperforms other classification models, with sensitivity and accuracy of 0.95 and 97.58%, respectively, on testing the data set. Examining the consumer repurchase intentions by considering both shopping mall and consumer characteristics makes this study unique.