Facile one-pot synthesis of bifunctional heterodimers of nanoparticles: a conjugate of quantum dot and magnetic nanoparticles

Sequential addition of sulfur and Cd(acac)2 into the colloid solution of FePt nanoparticles ( approximately 2.5 nm) under a reductive environment generates heterodimers of CdS and FePt with sizes of approximately 7 nm. The heterodimers exhibit both superparamagnetism and fluorescence, indicating that the discrete properties of the individual parts of the dimers are preserved. This simple methodology may lead to the production of large quantities of various heterostructures with tailored properties on the nanoscale.     

Ultracold two-component fermionic gases with a magnetic field gradient near a feshbach resonance

We study theoretically the ultracold two-component fermionic gases when a gradient magnetic field is used to tune the scattering length between atoms. For 6Li at the narrow resonance B0=543.25 G, it is shown that the gases would be in a coexistence of the regimes of BCS, Bose-Einstein condensation (BEC), and unitarity limit with the present experimental technique. In the case of thermal and chemical equilibrium, we investigate the density distribution of the gases and show that a double peak of the density distribution can give us a clear evidence for the coexistence of BCS, BEC, and unitarity limit.     

Nitrilotriacetic acid-modified magnetic nanoparticles as a general agent to bind histidine-tagged proteins

Using Nalpha,Nalpha-bis(carboxymethyl)lysine to react with FePt magnetic nanoparticles, we synthesized the FePt-NTA conjugate, which immobilizes Ni2+ ions and selectively binds to histidine-tagged proteins at concentration as low as 0.5 pM. This simple system serves as a useful alternative to existing protocols for protein separation and also acts as a versatile agent for transporting and anchoring proteins.     

A nanoscale dendrimer-based Fe24 cluster: synthesis and molecular self-assembly

We report the synthesis, characterisation and self-assembly of a nanoscopic Fe24 cluster using an organic dendrimer as a molecular substrate for building up well-defined molecular nanostructures.     

Using biofunctional magnetic nanoparticles to capture gram-negative bacteria at an ultra-low concentration

After conjugation to vancomycin (Van), chemically stable and highly magnetic anisotropic FePt magnetic nanoparticles (approximately 4 nm) become water-soluble and capture E. coli at 15 cfu mL(-1).     

Spatial Carrier Bi-frequency Fourier Transform Profilometry for the 3-D Shape Measurement of Object with Discontinuous Height Steps

1 IntroductionProjecting a single frequency lfringe pattern upon an Object and observing itsdeformation from a different view angle has been a common method for various threedimensional shape measurement techniques. An autpmatic analysis of the fringepatterns is normally carried out either by the FOurier transform method[IJ or by phasestepping['] of the fringe patterns. HOWever, these techniques have a disadvantage ofprincipal importance, the so-called indetedrinaCy tO a factor Of Zap, or …     

Coplanar Phase Shifters Based on Ferroelectric Thin Films

Barium strontium titanate (Ba_0.6Sr_0.4TiO₃, short for BST) thin films were prepared by RF-magnetron sputtering. The dielectric tunability, loss tangent, remanent polarization (2Pr) and coercive electric field (Ec) of the BST films are respectively 29.5%, 0.013, 2.29 μC/cm² and 22.27 kV/cm at 1 kHz and 20 V. The designed coplanar waveguide (CPW) phase shifter consists of 56 same sections. It is shown that the fabricated lines of electrodes are smooth and the widths at the tip of bottom electrodes are about 5 μm. At the central frequency of 28 GHz and a bias voltage of 20 V, the figure of merit is approximately 13°/dB.     

Calculation of the Effect on the Reflection of the Plane Electromagnetic Wave for Non-Magnetized Plasma with Different Electron Density Distributions

In this paper, shift operator finite-difference time-domain (SO-FDTD) method is applied for the calculation of the dispersive medium. The high efficiency and accuracy of this method is verified by calculating the reflection of the plane electromagnetic wave impinging on a non-magnetized plasma slab with different electron density distributions. The results show that the average electron density only determines overall trends of the reflection, and different distributions affect the oscillating process of the reflection. If the average electron density maintains the same, the distribution of electron density with homogenous or inhomogeneous alternation will sharply take effects on the reflection. And magnitude of alternation of electron density affects the incident frequency directly when the reflection tends to uniform.     

Realization of controllable etching for ZnO film by NH4Cl aqueous solution and its influence on optical and electrical properties

ZnO films were deposited on c-plane Al₂O₃ substrates by pulsed laser deposition. The etching treatments for as-grown ZnO films were performed in NH₄Cl aqueous solution as a function of NH₄Cl concentration and etching time. It was found that NH₄Cl solution is an appropriate candidate for ZnO wet etching because of its controllable and moderate etching rate. The influence of etching treatment on the morphology, optical and electrical properties of the ZnO films has been investigated systematically by means of X-ray diffraction, atomic force microscope, photoluminescence and Hall effect. The results indicated that the surface morphology and optical properties of the films were highly influenced by etching treatment.     

创设"问题情境"课堂教学案例——"闭合电路欧姆定律"教学设计

为什么教师在课堂上多次强调的问题，学生在学习中却屡屡犯错？学生为什么会提出一些非常简单的问题，甚至存在明显错误的思路和方法？难道仅仅是记忆力不好，学习不专注等因素造成的吗？其实教师有一定的责任．以往一节课基本上是教师一人唱“独角戏”，这种“牵着鼻子走”的教学模式，学生学到的只是这个问题的“是什么”、“为什么”和“怎么做”．一些需要学生一步一步深入思考的问题，却都是教师代替学生“解决”了．