Novel,liquid crystal formula to overcome LTPS LCD image sticking without adjustment of gamma code,optical, VHR and IS evaluation

In this article, novel n-FFS liquid crystal material from Slichem was used in order to elevate the anti-backlight long aging effect; a trace amount of free radical trap HALS-like additive was added, the principle of which can be expressed via Denisov cycle, confirmed by measuring the temporal VHR changes in test cells; three different resolution (FHD ~ QHD) models paired with N19 and N21 were selected for testing by comparing the actual panel. It is verified that the optimized material greatly improves the image sticking performance of the panel and keeping optical performance.     

考虑电网阻抗耦合的模块化多电平换流器交直流侧阻抗通用计算方法

以模块化多电平换流器(modular multilevel converter,MMC)为技术路线的柔性直流输电技术在风电接入、电网异步互联等领域迅速发展。MMC的阻抗建模是分析柔性直流输电系统振荡起源的重要依据。文中分析MMC在交、直流侧激励下的谐波传递机制,建立一种适用于交、直流侧阻抗计算的通用方法。对一次系统频域建模关联了MMC所连接的交、直流侧网络阻抗,并考虑包含解耦双同步参考坐标系锁相环及负序内环控制在内的全部控制模块。通过求解线性方程组对MMC阻抗进行计算,并在PSCAD/EMTDC环境中对双端背靠背MMC系统在多种工况下1～5kHz频段内进行扫频,验证该方法的准确性,并详细分析网络阻抗耦合、控制链路延时、功率等级、负序内环和外环控制等因素对MMC阻抗的影响。     

Adaptive prescribed time control for quadrotor formation with stochastic links failure

The formation control for multiple quadrotors subject to maintaining the formation configuration and collision avoidance in the situation of stochastic links failure is investigated in this paper. First, the distributed formation controller is designed, the position controller is developed to manage the desired formation of position, and the attitude controller is developed to control the translation and rotation movements of the quadrotor. Then, in order to avoid the collisions between multiple quadrotors and the obstacles, a potential energy function method is introduced into the quadrotor formation control combined with the nest adaptive control. Inspired by the design of event trigger controller, a communication compensation controller is designed to ensure the stability of quadrotor formation under the condition of random communication interruption and recovery. Moreover, a prescribed time function is designed, which means the convergence time of the formation system can be set in advance. The prescribed time stability of the formation control system is proved by Lyapunov theory. Finally, the simulation results verify the effectiveness and superiority of this method.     

Implementation and decoding method of OCC system based on MIMO

The application of high-frame-rate cameras as well as the complex image processing techniques will lead to a series of problems, such as high system cost and long transmission delay. In this paper, we introduce narrow-band filtering technology to reduce the impact of optical noise and reduce the complexity of image processing from the physical level. We also introduce multiple-input multiple-output (MIMO) technology into the optical camera communication (OCC) system to increase system transmission rate, and propose a light emitting diode (LED) array decoding algorithm based on the directional projection method to reduce the system delay. By accumulating the target pixel values in each row and column of the image, the proposed method then determines the position and boundary of the detected target to distinguish the target area from the background. Experimental results indicate that the communication distance can reach up to 5.5 m without error bits detected. When the LED array at the transmitter of this system flashes at a frequency of 12 Hz, the transmission rate can reach 126.32 bit/s.     

Application potential of bone marrow mesenchymal stem cell (BMSCs) based tissue-engineering for spinal cord defect repair in rat fetuses with spina bifida aperta

Spina bifida aperta are complex congenital malformations resulting from failure of fusion in the spinal neural tube during embryogenesis. Despite surgical repair of the defect, most patients who survive with spina bifida aperta have a multiple system handicap due to neuron deficiency of the defective spinal cord. Tissue engineering has emerged as a novel treatment for replacement of lost tissue. This study evaluated the prenatal surgical approach of transplanting a chitosan–gelatin scaffold seeded with bone marrow mesenchymal stem cells (BMSCs) in the healing the defective spinal cord of rat fetuses with retinoic acid induced spina bifida aperta. Scaffold characterisation revealed the porous structure, organic and amorphous content. This biomaterial promoted the adhesion, spreading and in vitro viability of the BMSCs. After transplantation of the scaffold combined with BMSCs, the defective region of spinal cord in rat fetuses with spina bifida aperta at E20 decreased obviously under stereomicroscopy, and the skin defect almost closed in many fetuses. The transplanted BMSCs in chitosan–gelatin scaffold survived, grew and expressed markers of neural stem cells and neurons in the defective spinal cord. In addition, the biomaterial presented high biocompatibility and slow biodegradation in vivo. In conclusion, prenatal transplantation of the scaffold combined with BMSCs could treat spinal cord defect in fetuses with spina bifida aperta by the regeneration of neurons and repairmen of defective region.     

La<Subscript>1−x</Subscript>Ag<Subscript>x</Subscript>FeO<Subscript>3</Subscript>/halloysites nanocomposite with enhanced visible light photocatalytic performance

La_1?xAg_xFeO₃/halloysites nanotubes (HNTs) nanocomposite was synthesized by sol–gel method. It was characterized by X-ray diffraction, transmission electron microscope, Fourier transform infrared spectroscopy and UV–visible diffused reflectance spectroscopy measurements. The photo-activity of the La_1?xAg_xFeO₃/HNTs nanocomposite was evaluated via degradation of methylene blue (MB) under visible-light irradiation. The results showed that the HNTs with unique pore structure favored the adsorption of organic molecules. Adequate Ag⁺ doping improved the absorption ability for visible light. The La_0.95Ag_0.05FeO₃/HNTs demonstrated the best photocatalytic performance, which achieved as high as 99 % for MB degradation exposed 2 h irradiation. However,further increasing of Ag⁺ doping gradually reduced the photocatalytic activity. The nanocomposite catalyst showed outstanding recyclability after eight cycles which still remained up to 90 %.