脉冲功率装置的脉冲形成单元研究

 介绍了所研制的脉冲功率装置的组成、脉冲形成单元的设计以及脉冲形成单元实验研究结果。研究了包含脉冲形成线的绝缘设计校验、装置的脉冲形成单元的抖动及其与主同步开关击穿延迟时间的抖动和脉冲输出开关的抖动的关系。实验结果表明：在3.6 MV脉冲电压作用下,脉冲形成线的前后尼龙隔板未出现表面闪络等绝缘问题,脉冲形成线的绝缘满足设计要求。主同步开关的抖动1.6 ns,脉冲输出开关的抖动小于3.1 ns,脉冲形成单元的整体抖动小于3.0 ns,满足装置同步性能要求。     

Directed Brain Network Analysis for Fatigue Driving Based on EEG Source Signals

Fatigue driving is one of the major factors that leads to traffic accidents. Long-term monotonous driving can easily cause a decrease in the driver’s attention and vigilance, manifesting a fatigue effect. This paper proposes a means of revealing the effects of driving fatigue on the brain’s information processing abilities, from the aspect of a directed brain network based on electroencephalogram (EEG) source signals. Based on current source density (CSD) data derived from EEG signals using source analysis, a directed brain network for fatigue driving was constructed by using a directed transfer function. As driving time increased, the average clustering coefficient as well as the average path length gradually increased; meanwhile, global efficiency gradually decreased for most rhythms, suggesting that deep driving fatigue enhances the brain’s local information integration abilities while weakening its global abilities. Furthermore, causal flow analysis showed electrodes with significant differences between the awake state and the driving fatigue state, which were mainly distributed in several areas of the anterior and posterior regions, especially under the theta rhythm. It was also found that the ability of the anterior regions to receive information from the posterior regions became significantly worse in the driving fatigue state. These findings may provide a theoretical basis for revealing the underlying neural mechanisms of driving fatigue.     

Transition-Metal-Catalyzed Regioselective Functionalization of Monophosphino-o-Carboranes

A facile approach to the synthesis of diaryl- and dialkyl-substituted monophosphino-o-carboranes by rhodium(I)-catalyzed phosphine-directed B^3,6−H activation has been developed for the first time. Upon switching rhodium(I) to palladium(II), C-arylated and B⁶-halogenated products were obtained by using tBuOLi and Li₂CO₃ as base, respectively. These discoveries provide some simple and efficient approaches to the modification of monophosphino-o-carboranes.     

Effects of minerals containing sodium,calcium, and iron on oxy-fuel combustion reactivity and kinetics of Zhundong coal via synthetic coal

Journal of Thermal Analysis and Calorimetry - The greatly high contents of alkali and alkali earth metals in Zhundong coal have a negative impact on the combustion and utilization of the coal,...     

A Targeted Nano Drug Delivery System of AS1411 Functionalized Graphene Oxide Based Composites

A novel method for the preparation of antitumor drug vehicles has been optimized. Biological materials of chitosan oligosaccharide (CO) and γ-polyglutamic acid (γ-PGA) have previously been employed as modifiers to covalently modify graphene oxide (GO), which in turn loaded doxorubicin (DOX) to obtain a nano drug delivery systems of graphene oxide based composites (GO-CO-γ-PGA-DOX). The system was not equipped with the ability of initiative targeting, thus resulting into toxicity and side effects on normal tissues or organs. In order to further improve the targeting property of the system, the nucleic acid aptamer NH₂-AS1411 (APT) of targeted nucleolin (C23) was used to conjugate on GO-CO-γ-PGA to yield the targeted nano drug delivery system APT-GO-CO-γ-PGA. The structure, composition, dispersion, particle size and morphology properties of the synthesized complex have been studied using multiple characterization methods. Drug loading and release profile data showed that APT-GO-CO-γ-PGA is provided with high drug loading capacity and is capable of controlled and sustained release of DOX. Cell experimental results indicated that since C23 was overexpressed on the surface of Hela cells but not on the surface of Beas-2B cells, APT-GO-CO-γ-PGA-DOX can target Hela cells and make increase toxicity to Hela cells than Beas-2B cells, and the IC₅₀ value of APT-GO-CO-γ-PGA-DOX was 3.23±0.04 μg/mL. All results proved that APT-GO-CO-γ-PGA can deliver antitumor drugs in a targeted manner, and achieve the effect of reducing poison, which indicated that the targeted carrier exhibits a broad application prospect in the field of biomedicine.     

Green synthesis of Fe3O4 nanoparticles for hyperthermia,magnetic resonance imaging and 5-fluorouracil carrier in potential colorectal cancer treatment

Research on Chemical Intermediates - Magnetite nanoparticles (Fe3O4 NPs) have received considerable attention in various biomedical applications due to their fascinating properties and multiple...     

Study on the performance assessment of a novel hybrid heat pump system modified with dedicated mechanical sub-cooler for domestic heating applications

Journal of Thermal Analysis and Calorimetry - This article investigates the performance of a novel hybrid heat pump system, which is developed to recover the waste heat from the flue gas of...     

Dismutation of Titanium Sub-oxide into TiO and TiO2 with Structural Hierarchy Assisted by Ammonium Halides

Black TiO_2−x attracts enormous attention due to its large solar absorption and improved conductivity. In this work, a novel structure of TiO_2−x with conductive TiO layer, performing full-spectrum absorption, was synthesized in one step by the unforeseen dismutation reaction of titanium sub-oxides (Ti_nO_2n−1) in ammonium halide atmosphere. For this new reaction, a possible mechanism of decomposition-etching-disproportionation-rehydrolysis process was proposed. The vital intermediate reactant TiCl₄, which verifies the assumption, has been captured in the form of (NH₄)₂TiCl₆, especially where Ti₂O₃ is the reactant. Furthermore, this work not only can nominate TiO as an alternative for noble metals or carbon materials in the aim to improve the electron conductivity and solar absorption of black TiO_2−x, which are important in electrochemistry and optoelectronics fields, but also can be a new route to synthesize special structures for other multivalent transition metals.