Search

There is a high toxicity and carcinogrenicity of aflatoxin B1 (AFB1) in food. Current detection of aflatoxin B1 is performed by a variety of methods including thin layer chromatography, high performance liquid chromatography, liquid chromatography-tandem mass spectrometry and immunoassay, but they all have some limitations. AFB1 detection research had obtained certain achievements based on nucleic acid aptasensor. The thee new detection technology based on the electrochemical nucleic acid aptasensor, optical nucleic acid aptasensor and PCR nucleic acid aptasensor had advantages and disadvantages. A new idea in which glucose meter was used as a detection instrument and combined with nucleic acid aptasensor for AFB1 qualitative analysis were to be experimental veried. Combining nucleic acid aptasensor with magnetic nanoparticle united with bio-recognition elements as the adsorbent for solid phase extraction (SPE) was expected to be a breakthrough in the future. [ABSTRACT FROM AUTHOR]

Abstract: We have investigated the structural and electrical transport properties of Nb-doped TiO2 films deposited on (100) LaAlO3 substrates by rf magnetron sputtering at temperatures ranging from 873K to 1073K. Films deposited below 998K are anatase, and mixed phases between anatase and rutile exist in the film grown at higher temperatures. We find that films deposited at low temperatures exhibit semiconductor behavior, while metallic conductivity is observed in the most conducting film deposited at 998K. For this sample, compared to electron–phonon scattering mechanism, electron–phonon-impurity interference effect plays an important role in its electron transport process. Moreover, the temperature coefficient of the resistivity for the film deposited at 1073K is negative from 2K to 300K. The temperature dependence of resistivity for the film is described by ∼exp(b/T)1/2 at temperatures from 80K down to 30K, and by the fluctuation induced tunneling model from 80K to 300K. [Copyright &y& Elsevier]

Brushless DC motor (BLDCM) has the problem of torque ripple due to its structural characteristics and traditional modulation mode, which limits its application range and especially in high precision servo system. A control method that combines the PWM-ON-PWM modulation mode with BUCK converter basis on position sensorless was proposed, to eliminate or suppress the torque ripple. Simulink results showed that the method can not noly completely eliminate the freewheel current of silent phase to eliminate the non-commutation torque ripple, but also decrease the commutation torque ripple in the running process of the motor. [ABSTRACT FROM AUTHOR]