[Qualitative analysis of compositions of anthraquinone series working solution by gas chromatography-mass spectrometry].

A method for the qualitative analysis of compositions of anthraquinone working solution (WS)/hydrogenated working solution (HWS) by gas chromatography-mass spectrometry (GC-MS) was developed. The composition of ethylanthraquinone (eAQ) WS/HWS was identified by GC-MS. Then the samples of amylanthraquinone (AAQ) WS/HWS were analyzed by GC-MS. Combined with the reaction mechanism, the composition of AAQ WS/HWS was inferred. The list of the degradation as well as the intermediate products in the industrial synthesis of H2O2 in anthraquinone WS was generated, and the information obtained regarding the composition of the anthraquinone WS/HWS was helpful in identifying and removing the unacceptable degradation products.

Incontinuous grain growth in cobalt nanocrystalline powders prepared by high-energy mechanical milling.

Cobalt nanocrystalline powders with the average grain size of about 17 nm were prepared by high-energy mechanical milling. Grain growth in highly pure and particle-containing nanocrystalline Co powders were investigated respectively by a series of annealing experiments at different temperatures. The characteristics of incontinuous grain growth were found in both the pure and the particle-containing nanocrystalline powders. It is proposed by the authors that the sharp increase in nanograin size in the transition between the low and high temperature regions is a result of enhanced grain growth promoted by the stored energy as a supplied driving force, based on which rapid grain growth occurs through a particular dominant mechanism of nanograin rotations in the pure nanocrystalline powders, and that through off-pinning of grain boundaries in the particle-containing nanocrystalline powders.

[A multifrequency phase-controlled driving system for ultrasound therapy].

Ultrasound therapy is a new type of therapy technology, there are hyperthermia and high intensity focused ultrasound surgery (HIFUS). Compared with a single frequency system, mutiple frequency system has an additional function to combine power patterns of different frequencies. This function increases the availability of power patterns to treat tumors of various shapes and depths. Therefore, we have in this article proposed a system with the ability to drive ultrasonic phased arrays of multiple resonant frequencies for ultrasound hyperthermia and HIFUS. The results show that this system is able to (1) drive multi-element applicators or phased arrays of a single resonant frequency through the multichannel power amplifiers, (2) concurrently drive transducer with different resonant frequencies, (3) adjust the relative phase and output power of each channel for the scanning ultrasonic focus, and (4) operate each channel with good output stability.