A generalized multilevel inverter based on T-Type switched capacitor module with reduced devices

Conventional multilevel inverters have problems in terms of their complicated expansion and large number of devices. This paper proposes a modular expanded multilevel inverter, which can effectively simplify the expansion and reduce the number of devices. The proposed inverter can ensure the voltage balancing of the voltage-dividing capacitors. The cascading of the T-type switched capacitor module and the step-by-step charging method of the switched capacitors enable the inverter to achieve high output voltage levels and voltage gain. In addition, the inversion can be achieved without the H-bridge, which greatly reduces the total standing voltage of the switches. The nine-level inverter of the proposed topology can be realized with only ten switches, obtaining a voltage gain that is two times larger. The above merits were validated through theoretical analysis and experiments. The proposed inverter has good application prospects in medium- and low-voltage photovoltaic power generation

A three-dimensional imaging detector based on nano-scale silver-related defects in X- and gamma-ray-irradiated glasses

Ag-activated phosphate glass, which is the most commonly known radiophotoluminescent (RPL) material, has the capability to operate not only dosimeters but also two- and three-dimensional (2D and 3D) dose imaging detectors in the same host. This passive detector is based on radiationinduced, optically active nano-scale defects. In this work, the transient-state optical properties of the blue and orange RPL were investigated using a time-resolved spectrum technique for 137Cs and 60Co gamma-ray-irradiated Ag-activated phosphate glass. Specifically, the blue RPL intensity with a decay time of 5 ns as a function of the depth at the vicinity of the surface was systematically examined to clarify an accurate dose distribution within the glass. Moreover, a feasibility study into the use of an RPL Ag-activated phosphate glass detector for fluorescent nuclear track imaging was demonstrated using a confocal fluorescence image microscope for the first time. © 2016 The Japan Society of Applied Physics

Effect of Biodiesel impurities (K, Na, P) on non-catalytic and catalytic activities of Diesel soot in model DPF regeneration conditions

Abstract(#br)The impact of Biodiesel impurities (Na, K and P) on the non-catalytic and catalytic reactivity of Diesel soot was evaluated under model DPF (Diesel Particulate Filter) regeneration conditions. Temperature-programmed oxidation (TPO) measurements confirmed that Na and K depositing into soot or on the surface of the catalyst enhanced the oxidative reactivity of soot under both O 2 and NO x + O 2 and Na-doped samples showed better results. However, the presence of P inhibited the non-catalytic and catalytic reactivity. These findings can be mainly attributed to the changes in nanostructure and surface chemical properties of the doped samples, characterized by Raman, high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), H 2 temperature-programmed reduction (H 2 -TPR) and NO temperature-programmed oxidation (NO-TPO). The result of this characterization evidenced that the presence of Na and K increased structural defects of soot and reduction ability of the catalyst. Moreover, Na-/K-doped catalysts presented higher oxidizing ability of NO into NO 2 , whereas the opposite trend was observed for the P-containing catalysts. In addition, higher structural disorder of Na-doped soot and higher alkali metal content on the surface of Na-doped catalyst might lead to enhanced reactivity in comparison to K-doped soot and catalyst

MiR-641 participates in the progression of breast cancer by modulation of RELN expression

Purpose: To examine the role of micro-ribonucleic acid 641 (miR-641) in breast cancer, and to uncover its possible molecular mechanism. Methods: MiR-641 expressions in breast cancer cell lines and tissues were determined using Real-time fluorescence quantitative reverse transcription-polymerase chain reaction (qRT-PCR), and the diagnostic potential value of miR-641 was assessed using receiver operating characteristic (ROC) curves. The survival of the patients was analyzed using Kaplan-Meier, and the cell viability and migration capacity were evaluated using Transwell and cell counting kit-8 (CCK-8) assay, and the downstream target gene of miR-641 was confirmed via dual-luciferase reporter gene assay. Finally, reversal assay was employed to corroborate the molecular mechanism that affects cell proliferation and migration via modulation of RELN. Results: MiR-641 was lowly expressed in breast cancer cell lines and tissues, and its expression in the metastasizing group was lower than that in the matched group (p < 0.05). It was also observed that miR-641 expression gradually decreased as the breast cancer advanced. Moreover, lower miR-641 expression revealed a poor prognosis, and up-regulating miR-641 suppressed the proliferative and migrative capacities of breast cancer cells. It was proven that RELN is a target gene of miR-641. RELN expression rose in breast cancer, and it was evidently and negatively correlated with that of miR-641. Finally, miR-641 regulated RELN, and it affected the proliferation and migration of cells. Conclusion: MiR-641 has an obviously decreased expression level in breast cancer, and facilitates the proliferative and migrative capacity of breast cancer cells probably by modulating the RELN expression. This study may provide new targets for the treatment of breast cancer

Suppression of Chattering in the Real-time Simulation of the Power Converter

International audienceThe achievement of the time-step below 500-ns in the field-programmable-gate-arrays (FPGAs)-based real-time simulation is of importance for the power converters having high switching frequencies. However, most of the existing focus on addressing the power converter modeling under the continuous conduction mode (CCM). Nevertheless, towards practical applications, the modeling of discontinuous conduction mode (DCM) with a light-load is of a greater challenge due to the chattering around zero point. In order to solve the chattering problem under the light-load, this paper proposes a zero-regulation (ZR) method for FPGA-based real-time simulation. The proposed ZR method can not only represent CCM and DCM with a unified formula but also solve the chattering problem and improve accuracy and stability. In addition, results using different switch models are also given to demonstrate the feasibility and the generality of the proposed method. Finally, a case study of the series load resonant (SLR) converter is presented. Simulation results are validated against a reference model at a 100-ns time step and a 10-kHz switching frequency

Characterization of CO and/or NO Adsorbed on Reduced Rh-V/SiO2 Catalyst by Infraed Spectroscopy

In situ infrared spectroscopy has been used to study CO and/or NO adsorbed on reduced Rh/SiO2 and Rh-V/SiO2 catalysts. On Rh/SiO2 catalyst reduced at 573K, CO adsorption results in the formation of linear and bridged CO species as well as gem-dicarbonyl to give adsorption bands at 2060, 1867, 2085 and 2028cm(-1) respectively; NO adsorption bands appeared at 1726 and 1650cm(-1). However, on V/SiO2 catalyst reduced at 573K, no CO bands were observed, and two NO bands appeared at 1907 and 1810cm(-1). Furthermore, the NO bands shifted to 1890 and 1756cm(-1) when the V/SiO2 catalyst was reduced at 773K. Introduction of vanadium to the Rh/SiO2 catalyst showed a slight effect on the intensity of the gem-dicarbonyl shifted upwards by about 10cm(-1). These results indicate that the electron transfer from Rh-0 to vanadium ions was enhanced in Rh-V/SiO2 catalyst. Also promotion of reduction of V oxide by Rh was observed during the pretreatment of Rh-V/SiO2 catalyst as detected by ESR experiment. From the results of CO and NO coadsorption, it was found that the absorbed NO sepcies decreased CO adsorption on Rh, particularly, the linear CO species was completely disappeared. For the effects of NO adsorption on CO adsorption, there are two possibilities: (1) direct replacement of CO with NO; (2) oxidation of Rh-0 sites through NO dissociative adsorption. During the coadsorption, two possible intermediates, i.e., RhCONO and Rh(CO)(2)NO, were suggested for the surface process, which requires further investigation

Contact-engineered reconfigurable two-dimensional Schottky junction field-effect transistor with low leakage currents

Abstract Two-dimensional (2D) materials have been considered promising candidates for future low power-dissipation and reconfigurable integrated circuit applications. However, 2D transistors with intrinsic ambipolar transport polarity are usually affected by large off-state leakage currents and small on/off ratios. Here, we report the realization of a reconfigurable Schottky junction field-effect transistor (SJFET) in an asymmetric van der Waals contact geometry, showing a balanced and switchable n- and p-unipolarity with the I ds on/off ratio kept >106. Meanwhile, the static leakage power consumption was suppressed to 10−5 nW. The SJFET worked as a reversible Schottky rectifier with an ideality factor of ~1.0 and a tuned rectifying ratio from 3 × 106 to 2.5 × 10−6. This empowered the SJFET with a reconfigurable photovoltaic performance in which the sign of the open-circuit voltage and photo-responsivity were substantially switched. This polarity-reversible SJFET paves an alternative way to develop reconfigurable 2D devices for low-power-consumption photovoltaic logic circuits