Non-superimposable mirror image crystals of enantiomers by spontaneous resolution and the chiral discrimination mechanism

Non-superimposable mirror image crystals of both enantiomers(S/R) of cyclicγ-alkenyl alcohol(2) have been recognized and remarkably identified by the naked eye.More interestingly,both crystals are an outcome of most astonishingly H-bond and intermolecularσ/π-πinteractions.They accounted for the relatively rare and less predictable spontaneous resolution with optical purity >99%ee from the racemic mixture.The chiral discrimination mechanism of this spontaneous resolution has also been proposed.     

Zeolite-fiber integrated optical chemical sensors for detection of dissolved organics in water

MFI zeolite coated optical fiber sensors have been developed for in situ detection of dissolved organics in water. The sensors operate by monitoring the optical reflectivity changes caused by the selective adsorption of organic molecules, i.e., 2-propanol or pentanoic acid in this study, from aqueous solutions in the zeolitic pores. Reversible and monotonic sensor signals were observed in response to the variation of 2-propanol concentration in water with fast response. However, the sensor exhibited a much slower response to pentanoic acid than to 2-propanol. It was also found that substitution of Si by Al in the MFI framework increased the adsorption of pentanoic acid that resulted in enhanced sensor responses.     

Synthesis of silica nanoparticles doped with [Ru(bpy)3]2+ and decorated with silver nanoclusters for the ratiometric photoluminescent determination and intracellular imaging of Cu(II) ions

Microchimica Acta - A sensitive and selective luminescent nanoprobe (referred to as DEPN) is designed for the determination of Cu(II) ions. DEPN shows two emission peaks, one at 602 nm and...     

Note: the role of external electric fields in enhancing ion mobility, drift velocity, and drift-diffusion rates in aqueous electrolyte solutions [J. Chem. Phys. 134, 114504 (2011)

The effect of external electric fields on enhancing ion mobility, drift velocity, and drift diffusion as a function of solution concentration has been investigated using molecular dynamics simulations. Our results show that the unusual nonlinear behavior observed when the solution concentration matches seawater is also observed when the concentration is reduced to half of that value. These results are of significance in designing processes for desalinating seawater using electro-deionization in which the concentration would decrease during salt removal, and for purification of brackish waters which also have lower salt content.     

Magnetic and thermoelectric properties of REMoN3 (RE = La,Ce, Pr,Nd, and Sm): A first-principles study

We investigated the magnetic and thermoelectric properties of REMoN₃ (RE = La, Ce, Pr, Nd, Sm) perovskites using the full potential linearized augmented plane wave (FP-LAPW) method. To overcome the problem of underestimation of electronic interaction, we employed the DFT + U approach to accurately map the electronic structure of these compounds. Our study shows an increasing trend in the magnetic moments with the increasing number of unpaired electrons in RE. Among these compounds, SmMoN₃ possesses a large magnetic moment, which is suitable for applications such as memory devices and sensors. Interestingly, all these perovskites display ferromagnetic behavior except CeMoN₃, which exhibits an antiferromagnetic nature. Furthermore, our analysis indicates n-type thermoelectric behavior in all these materials. The compound, namely PrMoN₃, exhibits a high figure of merit among REMoN₃, which can be improved by modifying the lattice sites.     

Low cost anisotropic etching of monocrystalline Si (1 0 0): Optimization using response surface methodology

Reduced surface reflectance and enhanced light trapping is required by any high efficiency solar cell. Anisotropic etching was done on silicon (1 0 0) by using tetramethyl ammonium hydroxide TMAH, (CH₃)₄NOH, solution at 85 °C. Process variables considered were solution concentration and time proposed by response surface methodology (RSM). An effective surface texture was resulted with reflectance less than 8% without antireflection coating. The antireflection mechanism was also co-related with the etch rate of Si. Optimized values predicted by RSM for time and TMAH concentration were 5 min and 3.50% respectively. The technique and optimization of parameters by using response surface methodology (RSM) could be valuable in the texturization process for high-efficiency Si solar cells.     

Peristaltic flow of Sisko fluid in a uniform inclined tube

We have analyzed an incompressible Sisko fluid through an axisymmetric uniform tube with a sinusoidal wave propagating down its walls. The present analysis of non- Newtonian fluid is investigated under the considerations of long wavelength and low Reynolds number approximation. The analytic solution is obtained using （i） the regular perturbation method （ii） the Homotopy analysis method （HAM）. The comparison of both the solutions is presented graphically. The results for the pressure rise, frictional force and pressure gradient have been calculated numerically and the results are studied for various values of the physical parameters of interest, such as α （angle of inclination）, b^＊ （Sisko fluid parameter）, Ф （amplitude ratio） and n （power law index）. Trapping phenomena is discussed at the end of the article.     

Imaging flow structure and species with atomic and molecular filters

Rayleigh and Raman scattering have not been widely used for flow field and combustion imaging because of their very low scattering cross-sections and because of interference from strong background light. With the use of sharp cut-off, atomic and molecular filters this background can be rejected while high throughput is maintained. The sharp cut-off edge of the filters provides for the possibility of using them for high-resolution spectral discrimination. Consequently, Rayleigh and Raman imaging are now becoming feasible and have the promise of providing quantitative images of temperature, velocity, pressure, density, species, and nonequilibrium phenomena. Because Rayleigh and Raman scattering arise from all molecules and are not affected by quenching, quantitative images can be taken of all dominant molecular species as well as thermodynamic and transport properties of complex flows, weakly ionized plasmas, and combusting fields.     

Total Cross Sections at High Energies—An Update

Current and future measurements for the total cross sections at E-811,PP2PP,CSM,FELIX,and TOTEM have been analyzed using various models.In the light of this study an attempt has been made to focus on the behavior of total cross section at very high energies.