The Huazhong University of Science and Technology is a public, coeducational research university located in Wuhan, Hubei province, China. As a national key university, HUST is directly affiliated to the Ministry of Education of China. HUST has been referred toas the flagship of China's higher education system after the Chinese Civil War. HUST manages Wuhan National Laboratories for Opto-electronics at Wuchang, which is one of the five national laboratories in China. Wikipedia.
Understanding the oxidative relationships of the metal oxo, hydroxo, and hydroperoxide intermediates with manganese(IV) complexes having bridged cyclams: Correlation of the physicochemical properties with reactivity
Yin G.,Huazhong University of Science and Technology
Accounts of Chemical Research | Year: 2013
Multiple transition metal functional groups including metaloxo, hydroxo, and hydroperoxide groups play significant roles in various biological and chemical oxidations such as electron transfer, oxygen transfer, and hydrogen abstraction. Further studies that clarify their oxidative relationships and the relationship between their reactivity and their physicochemical properties will expand our ability to predict the reactivity of the intermediate in different oxidative events. As a result researchers will be able to provide rational explanations of poorly understood oxidative phenomena and design selective oxidation catalysts. This Account summarizes results from recent studies of oxidative relationships among manganese(IV) molecules that include pairs of hydroxo/oxo ligands.Changes in the protonation state may simultaneously affect the net charge, the redox potential, the metal-oxygen bond order (M-O vs M-O), and the reactivity of the metal ion. In the manganese(IV) model system, [Mn IV(Me2EBC)(OH)2](PF6)2, the MnIV-OH and MnIV-O moieties have similar hydrogen abstraction capabilities, but MnIV-O abstracts hydrogen at a more than 40-fold faster rate than the corresponding MnIV-OH. However, after the first hydrogen abstraction, the reduction product, Mn III-OH2 from the MnIV-OH moiety, cannot transfer a subsequent OH group to the substrate radical. Instead the Mn III-OH from the MnIV-O moiety reforms the OH group, generating the hydroxylated product. In the oxygenation of substrates such as triarylphosphines, the reaction with the MnIV-O moiety proceeds by concerted oxygen atom transfer, but the reaction with the MnIV-OH functional group proceeds by electron transfer. In addition, the manganese(IV) species with a MnIV-OH group has a higher redox potential and demonstrates much more facile electron transfer than the one that has the MnIV-O group. Furthermore, an increase in the net charge of the MnIV-OH further accelerates its electron transfer rate. But its influence on hydrogen abstraction is minor because charge-promoted electron transfer does not enhance hydrogen abstraction remarkably. The Mn IV-OOH moiety with an identical coordination environment is a more powerful oxidant than the corresponding MnIV-OH and MnIV-O moieties in both hydrogen abstraction and oxygen atom transfer. With this full understanding of the oxidative reactivity of the MnIV-OH and Mn IV-O moieties, we have clarified the correlation between the physicochemical properties of these active intermediates, including net charge, redox potential, and metal-oxygen bond order, and their reactivities.The reactivity differences between the metal oxo and hydroxo moieties on these manganese(IV) functional groups after the first hydrogen abstraction have provided clues for understanding their occurrence and functions in metalloenzymes. The P450 enzymes require an iron(IV) oxo form rather than an iron(IV) hydroxo form to perform substrate hydroxylation. However, the lipoxygenases use an iron(III) hydroxo group to dioxygenate unsaturated fatty acids rather than an iron(III) oxo species, a moiety that could facilitate hydroxylation reactions. These distinctly different physicochemical properties and reactivities of the metal oxo and hydroxo moieties could provide clues to understand these elusive oxidation phenomena and provide the foundation for the rational design of novel oxidation catalysts. © 2012 American Chemical Society. Source
Huazhong University of Science and Technology | Date: 2015-02-12
A ride-through and recovery method for DC short circuit faults of a hybrid modular multilevel converter based high-voltage direct current transmission (MMC-HVDC) system, the hybrid MMC including multiple full-bridge sub-modules and half-bridge sub-modules, and the method including: 1) detecting whether a DC short circuit fault occurs, and proceeding to step (2) if yes and continuing detecting if no; 2) realizing ride-through of the DC short circuit fault; 3) detecting whether a DC residual voltage increases, and proceeding to step (4) if yes and continuing detecting if no; and 4) realizing DC short circuit fault recovery.
Huazhong University of Science and Technology | Date: 2015-05-07
A nonvolatile logic gate circuit based on phase change memories, including a first phase change memory, a second phase change memory, a first controllable switch element and a first resistor, wherein a first end of the first phase change memory serves as a first input end of an AND gate circuit, a first end of the second phase change memory serves as a second input end of the AND gate circuit, a first end of the first controllable switch element is connected to a second end of the first phase change memory, a second end of the first controllable switch element is grounded; one end of the first resistor is connected to the first end of the second phase change memory, the other end of the first resistor is grounded; and the first end of the second phase change memory serves as an output end of the AND gate circuit.
Huazhong University of Science and Technology | Date: 2015-04-22
An aircraft-based infrared image recognition device for a ground moving target, including an infrared non-uniformity correction module, an image rotation module, an image registration module, a multi-level filtering module, a connected domain labeling module, a target detection and feature recognition module, a process control module, and a FPGA-based interconnection module. The invention uses an ASIC/SoC chip for image processing and target recognition, the DSP processor and the FPGA processor, it is possible to enable a multi-level image processing and target recognition algorithm, to improve system parallel, and to facilitate an aircraft-based infrared image recognition method for a ground moving target. Meanwhile, embodiments of the invention effectively reduce power consumption of the device.
Huazhong University of Science and Technology | Date: 2015-12-31
A mesoscopic solar cell, including: a conductive substrate, a hole blocking layer, a mesoporous nanocrystalline layer, an insulation separating layer, and a hole collecting layer, and perovskite light absorption materials. The hole blocking layer, the mesoporous nanocrystalline layer, the insulation separating layer, and the hole collecting layer are sequentially laminated on the conductive substrate. The perovskite semiconductor materials are filled in the mesoporous nanocrystalline layer, the insulation separating layer, and the hole collecting layer, which enables the mesoporous nanocrystalline layer to be an active light absorption layer operating as a photoanode, and enables the insulation separating layer to be a hole transporting layer.