Oscillatory persistent currents in self-assembled quantum rings

We report the direct measurement of the persistent current carried by a single electron by means of magnetization experiments on self-assembled InAs/GaAs quantum rings. We measured the first Aharonov-Bohm oscillation at a field of 14 T, in perfect agreement with our model based on the structural properties determined by cross-sectional scanning tunneling microscopy measurements. The observed oscillation magnitude of the magnetic moment per electron is remarkably large for the topology of our nanostructures, which are singly connected and exhibit a pronounced shape asymmetry.     

Lie symmetries and solitons in nonlinear systems with spatially inhomogeneous nonlinearities

Using Lie group theory and canonical transformations, we construct explicit solutions of nonlinear Schr?dinger equations with spatially inhomogeneous nonlinearities. We present the general theory, use it to show that localized nonlinearities can support bound states with an arbitrary number solitons, and discuss other applications of interest to the field of nonlinear matter waves.     

Photo-induced Fluorescence of Fluometuron in a Continuous-flow Multicommutation Assembly

This paper deals with the photo-induced fluorimetric determination of the herbicide Fluometuron with the aid of a continuous-flow assembly of the emergent and new methodology known as Multicommutation which was provided with an on-line photoreactor. Maximum fluorescence intensity was observed at basic pH solutions, 1×10⁻⁴ mol l⁻¹ NaOH, after 1.4 min of irradiation and being the maximum at λ_exc 247.0 nm and λ_em 325.0 nm. The influence of different experimental parameters either chemical (pH, surfactants presence, solvent polarity and temperature) or hydrodynamic (time of photo-degradation, size and number of different segments and flow-rate) was tested. The linear dynamic range was from 0.01 to 4.0 mg l⁻¹ of Fluometuron; the inter-day reproducibility (as R.S.D.) of the slope was 0.001% and 1.7% from the peaks intra-day reproducibility. A large series of potential interferents was studied and finally the method was applied to human urine, soil, formulation and water samples.     

Combination of radon and stable isotope analysis as a tool for decision support concerning the remediation of NAPL-contaminated sites

The non-aqueous phase-liquid (NAPL)-contaminated aquifer at a major refinery site in Mexico was investigated. Owing to the depth of the contaminated aquifer section (NAPL source zone) of over 100 m below the surface, the actual aquifer material was not accessible for sampling. Information on the residual NAPL contamination of the aquifer could only be obtained indirectly by analysing groundwater samples from a few wells available at the site. To tackle the problem, an approach alternative to conventional groundwater analysis for dissolved NAPL was chosen. For evaluating the recent contamination and estimating its probable future development, the radioisotope radon-222 and the stable isotopes 13C, 34S and 18O were used as naturally occurring contamination tracers and process indicators. Radon was used as partitioning tracer for the approximate localization and semi-quantitative assessment of the NAPL source zone. The stable isotopes were used as indicators for naturally occurring biodegradation processes, which might potentially be implemented into future remediation schemes.     

含联苯三羧酸及二咪唑基吡啶配体的两个锌配位聚合物的合成、结构及荧光性质

以3,3′,5-联苯三羧酸(biphenyl-3,3′,5-tricarboxylic acid,H3bpta)、2,6-二(1-咪唑基)吡啶(2,6-bis(imidazole-1-yl)pyridine,bip)、Zn(NO3)2·6H2O和ZnCl2为原料,在水热条件下合成了配位聚合物{[Zn3(H2O)7(bpta)2]·5H2O}n(1)和{[Zn2Cl(bpta)(bip)2]·2H2O}n(2)。并利用红外、元素分析和X-射线单晶衍射等对其结构进行表征。X-射线单晶衍射分析表明:化合物1属于单斜晶系,C2/c空间群,a=3.317 1(11)nm,b=1.495 7(5)nm,c=0.695 1(2)nm,β=91.50°,Z=4;化合物2属于单斜晶系,P2/c空间群,a=1.960 4(4)nm,b=1.035 7(2)nm,c=1.998 7(4)nm,β=101.97(3)°,Z=4。化合物1通过bpta桥联Zn髤形成1D链,通过配位水与羧基氧之间的氢键作用构筑成3D结构。化合物2中bip桥联Zn髤构成1D螺旋链状结构,进一步通过bpta桥连形成2D网状结构。此外,对化合物1和2进行了热稳定性分析和荧光性质研究。     

Meta-analysis of CO2 conversion,energy efficiency,and other performance data of plasma-catalysis reactors with the open access PIONEER database

This paper brings the comparison of performances of CO₂ conversion by plasma and plasma-assisted catalysis based on the data collected from literature in this field, organised in an open access online database. This tool is open to all users to carry out their own analyses, but also to contributors who wish to add their data to the database in order to improve the relevance of the comparisons made, and ultimately to improve the efficiency of CO₂ conversion by plasma-catalys...     

Synthesis, Crystal Structure, Fluorescent and Thermal Properties of Sodium Tridecafluorodizirconate Na5Zr2F13 Compound

1 INTRODUCTION Considerable research effort on the heavy metal fluoride glasses like barium, zirconium fluoride and a series of rare-earth fluorozirconate compounds du- ring the last two decades was initiated by the broad optical transmission window of these glasses and thereby the potential for ultralow-loss optical fi- bers[1~10]. The fluorozirconate of alkali metals was first reported in 1938[11], and most of the sodium and potassium fluorozirconates were reported amongthe 1940s and 19…     

Synthesis and Crystal Structure of a New Zn(II) Nitronyl Nitroxide Complex [Zn(NIT4Py)(PDA)(H2O)3]

1 INTRODUCTION Nitronyl nitroxides, independently or in combina- tion with metal ions, have been one of the most wi- dely studied systems in molecular magnetism for understanding radical-radical or metal-radical inte- ractions as well as for synthesizing organic ferroma- gnets and metal-radical magnetic materials[1～4]. Up to now, lots of metal-radical complexes have been reported[5～8]. On the other hand, cooperative inter- molecular interactions, such as coordination bonds, hydrogen bon…     

Correlation Study on Sweetness of Amino Acid with Different Configurations and Quantum Chemical Parameters

1 INTRODUCTION Since the introduction of QSAR by Hansch and Fujita in 1964, Deutsch and Hansch have quickly used it in the study of nitrophenylamine sweet reagents. They found good correlation between their distribution coefficients in octanol/water system and sweetness degree. Subsequently, they detected that vibration of aroma-substituent compounds has so- mething to do with sweetness. Henceforth, statistic correlations between structure and sweetness ofseries compounds have been inv…     

Crystallization and Preliminary Crystallographic Studies of Luffaculin 1, a Ribosome-inactivating Protein from the Seeds of Luffa Acutangula

1 INTRODUCTION The ribosome-inactivating proteins (RIPs) are RNA N-glycosidases[1, 2] which inactivate ribosomes by cleaving a single N–C glycosidic bond between adenine and ribose at A4324 in the 28s rRNA of rat. Because of the removal of one adenine from rRNA, elongation factorⅡ(EF-2) can not bind to the 60S subunit, so RIPs can arrest protein synthesis. RIPs can be classified into three types based on the struc- tures of genes and mature proteins[3]. Type 1 RIPs with molec…