Tsinghua University

Other

Huawei Technologies Co., Limited

Boe Technology Group Co., Ltd.

Chengdu Boe Optoelectronics Technology Co., Ltd.

China Petroleum Chemical Corporation

Research Institute of Petroleum Processing, Sinopec

Kui Wang

Zedong Zheng

Yongdong Li

Lie Xu

Xiang Li

Li Zhu

Hong Nie

Dadong Li

Longhui Xue

Yahua Shi

Zhihai Hu

Qinghe Yang

Zongfang Lin

Xiangyun Long

Xuefen Liu

Xiaodong Gao

Jinpeng Zhu

Na Bi

Qinghe Liu

Weizheng Dong

Xiaohong Kang

Jing Xin

A circuit for controlling a DC voltage source current includes a low-voltage DC bus capacitor, a first set of power electronics half-bridge units, a first set of branch circuit inductors, and a first set of DC switches. All of the first set of power electronics half-bridge units are connected in parallel between a positive pole and a negative pole of a low-voltage DC bus and are also connected in parallel with the low-voltage DC bus capacitor, an output neutral point of each power electronics half-bridge unit is connected in series with one of the first set of branch circuit inductors and one of the first set of DC switches to form one of a first set of current-sharing branch circuits, and each power electronics half-bridge unit and the corresponding current-sharing branch circuit are used to be connected with a DC voltage source to form a DC voltage source branch circuit.

Circuit for controlling current of direct current voltage source and control method

Provided is a mask assembly, including: an annular mask frame; a supporting structure, located on a side of the mask frame, fixedly connected to the mask frame, and having an opening; and a mask structure, located on a side of the mask frame and fixedly connected to the mask frame, and including a strip-shaped mask body and a sheet-shaped mask piece corresponding to the opening, wherein the mask piece is fixedly connected to a side edge of the mask body and has a plurality of first through holes, wherein an orthographic projection of the mask body on a bearing surface of the mask frame does not overlap with an orthographic projection of the opening on the bearing surface, and an orthographic projection of the mask piece on the bearing surface overlaps with the orthographic projection of the opening on the bearing surface.

Mask assembly, display panel, and display device

The present disclosure provides a multi-level converter with triangle topology and control method thereof, related to the technical field of multi-level converters. In the converter, n DC capacitors connected in series form a vertical edge of a triangle and are as a DC bus, n switching tubes connected in series form a bevel edge of the triangle, switching tubes each connected between a neutral point of the DC bus corresponding to each layer and a point for connecting the switching tube on the bevel edge form a horizontal edge. Each time the layer is expanded by one, the number of levels increases by one. When a voltage across each capacitor is E, an AC output terminal Xn may output a total of n+1 levels.

Multi-level converter with triangle topology and control method thereof

This application provides a terminal interface display method and a terminal. A specific solution includes: determining, by a terminal, a frequently used touch area on a first side of the terminal in response to a first gesture input by a user on a first interface, where the first gesture is a gesture input by a finger on a first side of the user, the frequently used touch area is a touch area that is on a terminal interface and that has undergone user operation whose frequency or quantity of times is greater than a first threshold, and the first interface includes at least two application icons; and displaying, by the terminal, at least one frequently used application icon of the at least two application icons in the frequently used touch area on the first side.

Terminal interface display method and terminal

The present disclosure provides a single carrier based multilevel modulation method, a single carrier based multilevel modulation device, and a storage medium. In each control period, a modulated wave value corresponding to each of n switch pairs is obtained according to a reference voltage to obtain n modulated wave values, a triangular carrier having an amplitude of n is generated and compared with each of the n modulated wave values to obtain control signals for each of the n switch pairs, and for each phase, the control signals are input to the corresponding switch pairs of the phase bridge.

Single carrier based multilevel modulation method and device, and storage medium

A method and a device for voltage balancing of DC bus capacitors of an NPC four-level inverter are disclosed. The method includes: determining an optimal zero-sequence voltage, determining an actual reference voltage of each phase based on the optimal zero-sequence voltage; comparing respectively three preset carrier signals with the actual reference voltage of each phase to obtain three first control signals; determining three duty-cycle adjustment values based on a voltage of the intermediate bus capacitor; adjusting correspondingly the three first control signals based the three duty-cycle adjustment values to obtain three second control signals; inputting correspondingly the three second control signals to three first switches of an upper bridge corresponding to each phase; and inputting correspondingly complementary signals of the three second control signals to three second switches of a lower bridge corresponding to each phase.

Method and device for voltage balancing of DC bus capacitors of neutral-point clamped four-level inverter

The present invention provides a hydrogenation catalyst, containing a carrier, metal components of nickel, molybdenum and tungsten supported thereon, and an adjuvant component selected from the group consisting of fluorine and phosphor and combination thereof. In another embodiment, the present invention provides a hydrogenation catalyst, containing a carrier and metal components of nickel, molybdenum and tungsten supported thereon, wherein said carrier contains a molecular sieve. The present invention provides further use of said catalyst in the process for hydrogenating hydrocarbon oil. In comparison with a hydrogenation catalyst according to the prior art, the catalyst according to the present invention has a much higher activity.

Hydrogenation catalyst and use thereof

A guard catalyst, comprising an alumina support and molybdenum and/or tungsten and nickel and/or cobalt supported on the alumina support, wherein the total ammonia integral adsorption heat of said alumina support does not exceed 25 J/g, the percentage taken up by the ammonia integral adsorption heat of the ammonia differential adsorption heat greater than 100 kJ/mol does not exceed 10% of the total ammonia integral adsorption heat. Compared to the catalysts of the prior art, the guard catalyst has higher catalytic activity, less coke deposit, lower reduction rate of pore volume, better stability of activity, and higher strength.

Guard catalyst and a process for its preparation

Growing community of inventors

Beijing, China

Kui Wang