Enhanced coercivity in sponge magnets with three dimensionally ordered nanopores

Nanoporous magnets are new promising materials particularly useful in biological assays and ion separations. This letter deals with a simple method for making porous magnets composed of cobalt ferrite, where polymer colloidal spheres were used as sacrificial templates. Compared with the bulk congener the porous cobalt ferrite shows enhancements in coercive field and magnetization, which could be associated with the presence of nanopores ordered three dimensionally. Using the sponge magnet complete removal of magnetic Cu and Fe ions was achieved while partial removal was observed with porous silicate having the same size of nanopores.     

Quantum Circuits and Schr?dinger’s Cat States

Quantum systems that are confined to circuit geometries are called quantum circuits. Macroscopic superconducting circuits are quantum circuits which can be modelled using a Quantisation by Parts scheme based on the macroscopic wave function approach of Feynman. This paper studies the circuit composed of an input wire and an output plate. We find that in order to achieve a consistent theory of supercurrent flow we have to generalize the quantisation by parts scheme to quantise in a path space. The generalized theory predicts a current flow down the wire into the plane. In addition to a current flowing radially outwards in the plane, the theory allows a circulating current round the origin. Strikingly, the circulating current can flow clockwise or anti-clockwise in such a way as to generate a magnetic moment of magnitude half of a Bohr magneton for an orbiting electron in an atom and a magnetic flux half that of the magnetic flux quantum of a superconducting ring. There is also the possibility of a macroscopic superposition of the two states of opposing circulating currents resembling a Schr?dinger’s cat situation. Furthermore, we outline a setup involving an external magnetic field that may allow experimental tests of the theory.     

The investigation of electrochemical properties and ionic motion of functionalized copolymer electrolytes based on polysiloxane

The effect of EO side chain functionalization on the transport and electrochemical properties of polysiloxane electrolytes has been examined in this report. First, a study of the electrochemical stability of the electrolytes by linear sweep voltammetry shows that the polymer electrolytes have a negligible effect on the electrolyte stability windows. In addition, the parameters of cation mobility in polysiloxane electrolytes, such as ionic transference numbers and diffusion coefficients, were increased by increasing the lengths of the EO side chain. However, cation mobility in polymer structures is quite different compared to liquid-based systems and is probably suppressed, resulting in their polymer structure. Therefore, Positron Annihilation Lifetime Spectroscopy (PALS) was used to study the relationship between orthopositronium (o-Ps) lifetime, free volume radius, free volume of micro voids and EO side chain affection at different temperatures. Finally, a battery application with LiCoO₂ and LiFePO₄/polymer electrolyte/lithium metal electrode was monitored for its potential use in the future.     

Measurement of thermal radiative properties of penguin down and other fibrous materials using FTIR

Penguins live in the extremely cold Antarctic. Understanding the thermal radiative properties of penguin down may help us to develop super insulating materials. In this study, Fourier transform infrared spectroscopy (FTIR) was applied to measure the thermal radiative properties of penguin down and compare them with those of other fibrous materials. It was found that penguin and duck down are superior to other fibrous materials, such as polyester, Thinsulate and wool, at the same fibre volume fraction, in shielding the radiative heat transmission, largely due to their fine fibre diameter. There is an optimum fibre diameter at which the fibrous materials are at their best in blocking thermal radiation. The fibre diameter of penguin down is very close to this optimum value. The study further found that the relationship between the effective thermal radiative conductivity and fibre fineness may be better fitted with a quadratic curve.     

Synthesis of Human Cancer Associated Globo-H (MBr1) Glycosylamino Acid: Some Mechanistic and Conformational Reinvestigations

The synthesis of an extended globo-H (MBr1 antigen) in the form of a glycosylamino acid is reported. By careful NMR analysis, we found an interesting conformational "flip" on the E ring of some synthetic intermediates. An explanation offered for the successful [3+3] coupling of ABC acceptor 11 and DEF donor 10 possessing a C4 free hydroxyl to produce β-galactoside in azaglycosidations is reinforced.     

三头季铵盐阳离子表面活性剂合成菱形十二面体介孔二氧化硅单晶

由于介孔二氧化硅单晶规整的外观形貌和有序的内部孔道结构性能, 使其在微激光器件领域具有十分重要的潜在应用. 试着用高电荷密度的阳离子三头季铵盐表面活性剂(C18-2-3-1)作模板剂, 用正硅酸四乙酯作无机前驱体, 在硫酸介质中通过调变有机-无机物种之间的协同组装作用, 成功地合成了具有简单立方相Pm3n结构的介孔二氧化硅单晶. 扫描电子显微镜(SEM)观察到这种介孔二氧化硅单晶具有菱形十二面体形貌, X射线衍射(XRD)和透射电子显微镜(TEM)测试结果证实这种介孔单晶属于简单立方Pm3n对称结构. 氮气吸附数据测得这种单晶具有较大的BET比表面积(550 cm2/g), 较大的孔体积(BJH 0.20 cm3/g)和孔径(BJH 2.4 nm).     

Gold nanoparticles-carbon nanotubes modified sensor for electrochemical determination of organophosphate pesticides

An electrochemical sensor was developed for the detection of organophosphate pesticides based on electrodeposition of gold nanoparticles on a multi-walled carbon nanotubes modified glassy carbon electrode. Cyclic voltammetry was employed in the process of electrodeposition. Field emission scanning electron microscope and X-ray diffraction techniques were used for characterization of the composite. Organophosphate pesticides (e.g. parathion) were determined using linear scan voltammetry. A highly linear response to parathion in the concentration range from 6.0?×?10^?5 to 5.0?×?10^?7 M was observed, with a detection limit of 1.0?×?10^?7 M estimated at a signal-to-noise ratio of 3. The method has been applied to the analysis of parathion in real samples.     

Evaluation of effects of bivalent cations on the formation of purine-rich triple-helix DNA by ESI-FT-MS

The GGA triplet repeats are widely dispersed throughout eukaryotic genomes. (GGA)n or (GGT)n oligonucleotides can interact with double-stranded DNA containing (GGA:CCT)n to form triple-stranded DNA. The effects of 8 divalent metal ions (3 alkaline-earth metals and 5 transition metals) on formation of these purine-rich triple-helix DNA were investigated by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FT-MS). In the absence of metal ions, no triplex but single-strand, duplex, and purine homodimer ions were observed in mass spectra. The triple-helix DNA complexes were observed only in the presence of certain divalent ions. The effects of different divalent cations on the formation of purine-rich triplexes were compared. Transition-metal ions, especially Co²⁺ and Ni²⁺, significantly boost the formation of triple-helix DNA, whereas alkaline-earth metal ions have no positive effects on triplex formation. In addition, Ba²⁺ is notably beneficial to the formation of homodimer instead of triplex.