碱性介质中 (氢) 氧化铜修饰电极电催化氧化蔗糖

 A stable copper (hydr)oxide-modified electrode was prepared in 0.5 mol/L NaOH solution by cyclic voltammetry in the range of -250 to 1 000 mV. It can be used for electrochemical studies in the range of -250 to 1 000 mV without interfering peaks because there is no oxidation of copper. During an anodic potential sweep, the electro-oxidation of saccharose on Cu occurred by the formation of Cu^III and this reaction also occurred in the early stages of the reversed cycle until it is stopped by the negative potentials. A mechanism based on the electro-chemical generation of Cu^III active sites and their subsequent consumption by saccharose was proposed, and the rate law and kinetic parameters were obtained. The charge transfer resistance from theoretical and impedance studies was used to verify the mechanism. Under chronoamperometry regimes, the reaction followed Cottrellian behavior. The transfer of up to 21 electrons was observed in further investigations of the electro-oxidation of saccharose on a (hydr)oxide Cu rotating disk electrode.     

A new multiobjective allocator of capacitor banks and distributed generations using a new investigated differential evolution

This article has investigated a new multiobjective allocation of optimal sizing and sitting of distributed generation (DG) units and capacitor banks in simultaneous mode to improve reliability and reduce energy losses. The proposed method consists of four objectives, that is, cost of energy not supplied, system average interruption duration index, costs of energy loss and investment. A novel structure differential evolution has been suggested to solve this nonlinear complex problem and its results are compared with related values of genetic algorithm and simple differential evolutionary algorithm. In addition to the novel objective function, the other contribution of this article is proposing a new model for load and energy cost. Three types of DGs, that is, wind turbine, solar cell, and diesel generator have been used in placement process. To verify the comprehensiveness of the proposed function, three scenarios have been introduced: scenario i: first, placement of DGs, then capacitor banks, scenario ii: first, placement of capacitor banks, and then DGs, and scenario iii: simultaneous placement of DGs and capacitor banks. Simulations have been carried out on one part of practical distribution network in Metropolitan Tabriz in North West of Iran. The results of simulations have been discussed and analyzed using the five novel indices. The obtained simulation results using proposed function shows that the simultaneous placement of DGs and capacitor banks results in more reduction of the energy losses and increase improvements of reliability indices as well as voltage profile. © 2013 Wiley Periodicals, Inc. Complexity 19: 40–54, 2014     

Gain-bandwidth trade-off in a transistor laser: quantum well dislocation effect

The Authors report an analytical model to investigate optoelectronic characteristics reliance of a Transistor Laser on Quantum Well Location. Using simulated base recombination lifetime, optical frequency response for different quantum-well locations extracted. Slipping the well towards the collector, improves the optical bandwidth where a maximum of ≈54 GHz is observed. No resonance peak, limiting factor in diode lasers, is occurred in this enhancement method. Analyzing current gain (β) as a function of the quantum well location, exhibits a decrease in β when the well moved in the direction of the collector so that a trade-off between optical and electrical properties of transistor laser is evident. The trade-off is utilized in conjunction with previously reported experimental researches to find an optimum place of quantum well for desired performance.     

Alternative configurations for cutting machines in a tube cutting mill

In a steel tube mill where an endless stream of steel tube is supplied from a manufacturing facility, trim waste is never made regardless of cutting patterns used and the standard cutting stock problem seems meaningless. Therefore, the continuous stock cutting problem with setup is introduced to minimize the sum of cutting time and pattern changing time to meet the given demand. We propose a new configuration of cutting machines to achieve higher production efficiency, namely the open-ended configuration as opposed to the traditional closed-ended configuration, thereby two variants of the problem are defined. We propose linear formulations for both problems using binary expansion of the number of pieces of different types in a pattern. Furthermore, we define the time for pattern change as a linear function of the number of knives used in the pattern to be more realistic. Computational studies suggest that the open-ended cutting machine may improve the production time by up to 44% and that our linear formulations are more efficient than the existing ones.     

Hydrophilic alginate based multidentate biopolymers for surface modification of CdS quantum dots

We report that sodium alginate and its graft-copolymers with (2-dimethylaminoethyl) methacrylate may attach to the surface of colloidal CdS-thioglycerol quantum dots (QDs) via a ligand exchange process and result in water-soluble and highly stable QD supramolecules. Optical properties of modified QDs in water showed that the emission intensity of QDs was still high after surface passivation.     

Dynamics of tractor lateral overturn on slopes under the influence of position disturbances (model development)

In order to investigate the effects of forward speed, ground slope and wheel–ground friction coefficient on lateral stability of tractor at the presence of position disturbances, a tractor dynamic model was developed. In this model two types of instability were considered: instability due to overturn and skid and for each case the stability index was determined. Different geometries and mass specifications of tractor MITSUBISHI-2501D were used to examine the model. According to the results of this model forward speed and ground slope had a reverse effect on all stability indexes. Moreover stability of this tractor was more affected by tractor skidding than overturning. Therefore to improve the overall stability of this tractor, preference should be on increasing the tractor stability index derived from skid dynamics of tractor.     

Spectral and thermal studies of divalent transition metal with indole-2-carboxylic acid and 4-substituted hydrazinethiocarbamide

Ternary complexes of Co(II), Ni(II) and Cu(II) with indole-2-carboxylic acid (A) and 4-substituted hydrazinethiocarbamide (L) [4-phenylhydrazinethiocarbamide (L(1)), 4-benzylhydrazinethiocarbamide (L(2)) and 4-(2-propenyl)hydrazinethiocarb-amide (L(3)) were prepared. The structure of the complexes was characterized by microchemical analysis, molar conductance, electronic, IR, (1)H-NMR, mass spectra as well as thermogravimetric studies. An octahedral structure is suggested for Co(II), Ni(II) and Cu(II) ternary complexes.     

Ultrafast MRI of the fetus: an increasingly important tool in prenatal diagnosis of congenital anomalies

Objective

To demonstrate the additional utility of ultrafast magnetic resonance imaging (MRI) of the fetus in the evaluation of sonographically detected or equivocal fetal congenital anomalies.

Material and Methods

Twenty five pregnant women with ultrasound detected fetal congenital anomalies underwent ultrafast fetal MRI.

Results

MRI findings altered the diagnosis of two cases of giant arachnoid cyst and sizable interhemispheric cyst associated with agenesis of the corpus callosum. MRI added additional findings of occult spinal diastematomyelia in two out of four cases of Chiari/meningocele malformation. MRI revealed impaired sulcation and unilateral cleft palate in suspected case of Walker-Warburg syndrome. In the remaining 18 cases MRI confirmed the diagnosis of Meckel–Gruber syndrome in three cases, hydronephrosis in six cases, cerebral ventriculomegaly in five cases, isolated omphalocele in three cases and findings suggestive of aneuploidy in the last case.

Conclusion

Ultrasound is the screening method of choice for evaluation of the fetus. Ultrafast MRI is a complementary adjunctive modality with excellent tissue contrast that can image the fetus in multiple planes and add information in sonographically detected or equivocal congenital anomalies that may be significant to establish definitive accurate diagnosis and hence adequate management and counseling.