No abstract

Berberine, palmatine, alizarin, purpurin, indigotin, and indirubin which were the major coloring compounds of Phellodendron bark, madder, and indigo plant were thermally degraded in 100°C oven in liquid dye form and also in silk dyed with five of these pigments. A mixed dye solution of six coloring compounds was prepared in DMSO solution and was thermally degraded for up to 7 days. Silk were dyed using either a mixed dye solution of five dyes or individual dye solutions and each were degraded for 7 and 14 days, respectively, and the dye was extracted from the samples for the HPLC analysis. The concentration of coloring compounds in the degraded samples were analyzed by HPLC-DAD-MS and the color difference (ΔE) of the degraded silk was examined using a spectro-colorimeter. Alizarin and purpurin were more resistance to degradation than other coloring compounds both when in solution form and in silk dyeings. And such result was verified by the color difference measurement of the degraded silk dyed with individual dye solution. The resistance of alizarin and purpurin to thermal degradation was highly likely due to the fomation of fiber-metal-dye chelated complex by alum or iron mordanting before dyeing.

A 1500 V three-level forward converter with phase-shifted control is proposed to meet the requirements on mediumand high-voltage DC bus of photovoltaic grid-connected system. The architecture of 1500 V DC bus is established by filtering the phase-shifted outputs in series centrally, in which the internal filters of each DC/DC converter are removed. The three-level voltage is superimposed by phase-shifting the rectified output voltages in series, which is beneficial to decrease the inductor current pulsation, diminish the ripple of output voltage and improve the system efficiency. The centralised filter contributes to downsizing the filter and reducing the system cost. With the introduction of parallel-series structure, the characteristics of lowvoltage stress are retained and the power transmission is improved. Meanwhile, the minimum value of total harmonic distortion (THD) with phase-shifted control is obtained through the Fourier decomposition of three-level voltage waveform. By analysing the variation rule of THD with the change of conduction angle, the optimal steady-state operating point of the converter is achieved. The operating principle of the proposed system is presented minutely in this study and a prototype has been established. The experimental results verify the validity of the proposed converter.

A mitochondria-targeted ratiometric two-photon fluorescent probe (Mito-MPVQ) for biological zinc ions detection was developed based on quinolone platform. Mito-MPVQ showed large red shifts (68nm) and selective ratiometric signal upon Zn2+ binding. The ratio of emission intensity (I488 nm/I420 nm) increases dramatically from 0.45 to 3.79 (ca. 8-fold). NMR titration and theoretical calculation confirmed the binding of Mito-MPVQ and Zn2+. Mito-MPVQ also exhibited large two-photon absorption cross sections (150GM) at nearly 720 nm and insensitivity to pH within the biologically relevant pH range. Cell imaging indicated that Mito-MPVQ could efficiently located in mitochondria and monitor mitochondrial Zn2+ under two-photon excitation with low cytotoxicity.