Optoelectronic studies of sol-gel derived nanostructured CdO-ZnO composite films

Compositional dependence of the optoelectronic properties of sol-gel derived CdO-ZnO composite films with volume ratio of Cd:Zn ranging from 1:0 to 0:1 (with a step of 1/4) has been studied. After heat treatments in air the prepared thin films were investigated by studying their structural, morphological, d.c. electrical and optical properties. X-ray diffraction (XRD) results suggest that the samples are polycrystalline and the crystallinity of them increased with Cd ratio. The average grain size is in the range of 20-34 nm. As composition and structure changed due to the Cd volume ratio, the order of the carrier concentration was varied from 10¹⁶ to 10²⁰ cm⁻³ with Cd ratio and the mobility increased from less than 2 to 45 cm² V⁻¹ s⁻¹. It was found that the transmittance and the band gap decreased as Cd ratio increased. The optical constants of the film were studied and the dispersion of the refractive index was discussed in terms of the Wemple-DiDomenico single oscillator model. The real and imaginary parts of the dielectric constant of the films were also determined. The volume energy loss (VELF) increases more than the surface energy loss (SELF) at their particular peaks. The third-order nonlinear polarizability parameter is higher for CdO-ZnO thin films with higher concentration of cadmium oxide.     

Lack of association between childhood common acute lymphoblastic leukaemia and an HLA-C locus dimorphism influencing the specificity of natural killer cells

Previous serological studies documenting an association between acute lymphoblastic leukaemia (ALL) and HLA-Cw antigens suggested that the HLA-C locus might influence susceptibility to ALL. However, associations with more than one Cw antigen suggest that polymorphic variants shared by more than Cw allele could be involved. Recent studies have shown that the HLA-C locus encodes two ligands (NK1 and NK2) recognized by receptors on natural killer (NK) cells. HLA-Cw alleles encoding these ligands are dimorphic, dependent on whether they encode one or other NK ligand. To determine whether susceptibility to the common (CD10+) form of childhood ALL (c-ALL) is associated with NK1 or NK2, we carried out a molecular analysis of 94 childhood c-ALL patients and 136 infant controls. We found no difference in the frequency of NK1 and NK2 alleles, phenotypes or genotypes between the patients and controls, suggesting that this does not explain the role of the HLA-C locus in susceptibility to childhood c-ALL.     

Minimizing the Discrepancy Between Source and Target Domains by Learning Adapting Components简

Predicting the response variables of the target dataset is one of the main problems in machine learning. Predictive models are desired to perform satisfactorily in a broad range of target domains. However, that may not be plausible if there is a mismatch between the source and target domain distributions. The goal of domain adaptation algorithms is to solve this issue and deploy a model across different target domains. We propose a method based on kernel distribution embedding and Hilbert-Schmidt independence criterion （HSIC） to address this problem. The proposed method embeds both source and target data into a new feature space with two properties： 1） the distributions of the source and the target datasets are as close as possible in the new feature space, and 2） the important structural information of the data is preserved. The embedded data can be in lower dimensional space while preserving the aforementioned properties and therefore the method can be considered as a dimensionality reduction method as well. Our proposed method has a closed-form solution and the experimental results show that it works well in practice.     

Achievement of optimal aluminum flake orientation by the use of special cubic experimental design

In the present investigation, attempts were made to predict the effect of variations in a coating's composition on aluminum flake orientation by means of a special cubic experimental design. The results showed that there seems to be a critical concentration of aluminum flake, above which the surface parallel orientations of these flakes as well as the mechanical properties of the free coatings’ film begin to decrease. Further analysis of the results showed that for a given cellulose acetate butyrate (CAB) resin content, a linear dependency was found to exist between the orientation attribute (i.e. λ) and the mechanical attribute (i.e. the Young's modulus). Furthermore, the relation ship between the appearance attribute (i.e. the flop-index) and the orientation attribute was best represented by a logarithmic function.     

One-Pot Synthesis of Spiro[chromeno[2,3-c]pyrazole-4,3′-indoline]-diones Using Sulfonic Acid Functionalized Nanoporous Silica SBA-Pr-SO3H and Study of Their Antimicrobial Properties

A novel and clean one-pot synthesis of spiro[chromeno[2,3-c]pyrazole-4,3′-indoline]-2′,5(6H)-diones via cyclocondensation reaction of isatins, 1,3-cyclohexadiones, and pyrazolone in aqueous media using SBA-Pr-SO₃H (sulfonic acid-functionalized mesoporous silica) as an efficient heterogeneous solid acid catalyst was reported. The antimicrobial activities of synthesized compounds have been tested.     

Design of a new scheme to indicate the domain of applicability of near singular approach in 2D BEM

The Gauss–Legendre integration is not appropriate for singular and nearly singular integrations in BEM. In this study, some criteria are introduced for recognizing the nearly singular integrals in integral form of Laplace equation. At first, a criterion is obtained for constant element and consequently higher order elements are investigated. To indicate this near singular approach, there are different formulations amongst which the Romberg method was selected due to its compatibility with analytical integration. The singular integrals were carried out by composing the Romberg method and midpoint rule. The potential functions over geometrically linear BEM elements can be defined in the form of constant, linear or other types of interpolation functions. In those elements, the Gauss–Legendre integration will be accurate, if the source point is placed out of the circle with a diameter equal to element length and its center matched to midpoint of the element. Also, some criteria are obtained for parabolic function of geometry over an element.     

An approach to design and fabrication of a piezo-actuated microdroplet generator

In this research, a piezo-actuated microdroplet printing device for drop on demand (DOD) is studied. Microdroplet devices are used in applications such as inkjet printing, rapid prototyping, and production of metal powder. An experimental device is designed and manufactured, in which the fluctuation of a flexible diaphragm–by a piezoelectric element–pushes the liquid out of the nozzle and produces droplets. The deflection of diaphragm due to different voltages is investigated by analytical and experimental study. In experiments, beside deflection voltage, the effect of suction and compression time and nozzle diameter on droplet size, droplet velocity, satellite droplets, and cutoff length is also investigated. High-speed camera is used to take photo of the formation of droplets. In order to calculate droplet diameter and velocity, outputs of high-speed camera are processed by MATLAB R2008a. Results obtained by analytical and experimental are in good agreement with each other and could be used to control droplet properties. It is shown that the device is able to produce droplet of diameter from 450 to 1,000 μm. Velocity of droplet can be also controlled in a range of about 0.2 to 1.4 m/s. The repeatability is investigated by ink printing on a paper attached to a rotary table.     

Novel superhydrophilic and hydrophobic nanostructured agar-like zirconia thin films: manipulating of morphology with PEG/CTAB

In this paper, a thorough study is dedicated to the manipulating of nanostructured zirconia thin films prepared by a sol–gel process with the focus on the wetting properties. It is observed that by engineering the amount of cetyltrimethylammonium bromide [[N(CH₃)₃] Br] (CTAB) and polyethylene glycol (PEG) in zirconium chloride precursor solution, the novel agar-like morphology with random orientation can be grown. Different morphologies are observed by changing the amount of PEG in the solution. All the prepared samples in this method show tetragonal phase after annealing at 500 °C for 1 h. The crystallite sizes have a direct correlation with the ratio of lattice parameters. The optical band gap is estimated by Kubelka–Munk method. Modified ZrO₂ thin films at an optimum ratio of PEG to CTAB annealed at 500 °C and present water contact angle lower than 3° (without UV illumination) which indicates their superhydrophilic properties. The analytical results of SEM images of samples annealed at 500 °C are also reported. Spreading and wicking of liquid through the nanochannels which are formed in the vacant spaces between nanorods lead to superior wetting property. Annealing temperature also strongly affects the wettability of agar-like zirconia thin films. Agar-like ZrO₂ thin films are obtained with superhydrophilic behavior by annealing at 500 °C. Similar agar-like morphology is also observed with hydrophobic character by annealing at 200 °C. The introduced preparation method in this paper provides an easy route to fabricate superhydrophilic agar-like ZrO₂ thin films without further processing.     

Design,synthesis, and nanoengineered modification of spherical graphene surface by layered double hydroxide (LDH) for removal of As(III) from aqueous solutions

In this study, new nano spherical graphene modified with LDH (Layered Double Hydroxide) was prepared and used to remove As(III) ion from aqueous solutions. At first, graphene oxide was synthesized from graphite using a well-known Hammer method. The obtained graphene oxide solution was sprayed in octanol solution under different temperatures and sprayed speed as influenced variables. The structure and physical characterization of synthesized spherical graphene oxide were determined by various techniques, including FT-IR, N₂ adsorption–desorption, SEM, TEM, and EDX. In the next step, the hydrothermal method was applied to deposition LDH on the spherical graphene oxide. The synthesized spherical graphene modified by LDH was used to remove As(III) as a toxic heavy metal ion. The effect of influenced variables including pH, contact time, amount of sorbent, and type eluent studied and the optimum values were as 8, 30, 50, and HCl (0.5 mol·L^-1), respectively. After optimization, the studied sorbent was shown a high adsorption capacity (149.3 mg·g^-1). The adsorption mechanism and kinetic models exhibited good agreement with the Langmuir isotherm and pseudo-second-order trends, respectively. Besides, the synthesized product was tested for seven times without significant loss in its sorption efficiency.