No-reference quality assessment of dynamic sports videos based on a spatiotemporal motion model

This paper proposes an approach to improve the performance of no-reference video quality assessment for sports videos with dynamic motion scenes using an efficient spatiotemporal model. In the proposed method, we divide the video sequences into video blocks and apply a 3D shearlet transform that can efficiently extract primary spatiotemporal features to capture dynamic natural motion scene statistics from the incoming video blocks. The concatenation of a deep residual bidirectional gated recurrent neural network and logistic regression is used to learn the spatiotemporal correlation more robustly and predict the perceptual quality score. In addition, conditional video block-wise constraints are incorporated into the objective function to improve quality estimation performance for the entire video. The experimental results show that the proposed method extracts spatiotemporal motion information more effectively and predicts the video quality with higher accuracy than the conventional no-reference video quality assessment methods.     

激光冷却铬原子的3维仿真分析

为了研究铬原子在激光冷却场中的3维表现形式,分析和探讨了铬原子与激光冷却场的相互作用过程,并基于半经典理论的多普勒力和偏振梯度冷却力的3维特性,采用4阶龙格-库塔算法模拟铬原子的3维运动轨迹,同时得到了铬原子的3维落点分布状态,当铬原子束经过激光冷却场后,其发散角变小,速率降低。结果表明,铬原子3维仿真结果与2维情况下的铬原子分布相吻合,并且能提供更全面和丰富的冷却信息。     

简介HXD3机车电传动系统及saber仿真软件

随着电力电子技术和微电子技术的发展,交流变频理论也在飞快的发展。从上世纪60年代起,交流变频的控制方法经历三次大的发展变化,目前以矢量控制和直接转矩控制技术为主导。大连机车厂生产的和谐HXD3型电机机车采用先进的PWM矢量控制等技术。应用saber仿真软件,仿真复杂的机车电传动系统具有良好的模拟实况的效果。     

Design of unidirectional emission silicon/Ⅲ-Ⅴ laser for on-chip interconnects

We propose a unidirectional emission silicon/Ⅲ-Ⅴ laser,which comprises an Ⅲ-Ⅴ quantum wells microdisk connected to an output waveguide and a silicon-on-insulator (SOI) waveguide.Characteristics of the ...     

复合超声振动游离磨料抛光设备的三维设计及运动仿真

在复合超声振动的游离磨料抛光设备的设计中,采用三维设计的方法,利用Solidworks对该设备进行了三维建模、装配设计及机构运动仿真,实现了CAD/CAE的集成,提高了产品的设计效率和设计质量,本文的设计方法也可为其它产品的设计提供参考。     

0.7CaTiO_3-0.3(La_xNd_(1–x))AlO_3微波介质陶瓷的研究

利用传统固相反应法制备了具有不同LaAlO3含量的0.7CaTiO3-0.3(LaxNd1–x)AlO3(以下简称CTLNA)系微波介质陶瓷,研究了所制CTLNA陶瓷的微观结构和微波介电性能。结果表明,用x=0.5的La3+取代Nd3+能有效促进样品晶粒的均匀分布,降低样品的气孔率。少量添加SrTiO3能进一步增加样品的致密度,提高CTLNA系微波陶瓷的介电性能。经原料组分及工艺优化,制备的0.7(Sr0.01Ca0.99)TiO3-0.3(La0.5Nd0.5)AlO3样品密度高、晶相均匀,其微波介电性能如下:εr=45.87,Q.f=41 612 GHz(4 GHz),τf=10×10–6/℃。     

掺碳氧化铟薄膜的铁磁性研究

采用磁控溅射法在Si(100)衬底上制备了掺碳氧化铟(In2O3:C)薄膜,溅射过程分别在衬底温度为室温和550℃的条件下进行。通过测试所制In2O3:C薄膜的XRD谱和磁化曲线,研究了In2O3:C薄膜的结构和铁磁性能,并探讨了其铁磁性的起源。结果显示,随着含碳量的增加,In2O3:C薄膜的饱和磁化强度先增大后减小;此外,氧空位缺陷浓度高的样品其铁磁性也更强,这表明氧空位缺陷与In2O3:C薄膜的铁磁性起源有直接的关系。     

Co_2O_3掺杂对0.965MgTiO_3-0.035SrTiO_3微波介质陶瓷性能的影响

采用传统电子陶瓷制备方法研究了Co2O3(1.5%～5.0%,质量分数)掺杂的0.965MgTiO3-0.035SrTiO3(MST0.035)微波介质陶瓷,分析了Co2O3含量对MST0.035陶瓷的烧结性能、晶相结构、显微形貌以及微波介电性能的影响。结果表明:Co2O3的掺杂促进了MST0.035陶瓷的烧结。随着Co2O3掺杂量的增加,陶瓷介电常数略有下降,谐振频率温度系数以及品质因数增加,同时中间相MgTi2O5逐渐减少直至完全消失。当Co2O3掺杂量为质量分数3.0%时,MST0.035陶瓷的烧结温度由1 380℃降低到1 290℃,其烧结所得的样品具有优良的微波介电性能:谐振频率温度系数τf=–2.53×10–6/℃,高的品质因数Q·f=19 006 GHz和介电常数εr=20.5。     

Osteoconductive Performance of Carbon Nanotube Scaffolds Homogeneously Mineralized by Flow‐Through Electrodeposition

The treatment of bone lesions, including fractures, tumor resection and osteoporosis, is a common clinical practice where bone healing and repair are pursued. It is widely accepted that calcium phosphate‐based materials improve integration of biomaterials with surrounding bone tissue and further serve as a template for proper function of bone‐forming cells. Within this context, mineralization on preformed substrates appears as an interesting and successful alternative for mineral surface functionalization. However, mineralization of “true” 3D scaffolds –in which the magnitude of the third dimension is within the same scale as the other two– is by no means a trivial issue because of the difficulty to obtain a homogeneous mineral layer deposited on the entire internal surface of the scaffold. Herein, a “flow‐through” electrodeposition process is applied for mineralization of 3D scaffolds composed of multiwall carbon nanotubes and chitosan. It is demonstrated that, irrespective of the experimental conditions used for electrodeposition (e.g., time, temperature and voltages), the continuous feed of salts provided by the use of a flow‐through configuration is the main issue if one desires to coat the entire internal structure of 3D scaffolds with a homogeneous mineral layer. Finally, mineralized scaffolds not only showed a remarkable biocompatibility when tested with human osteoblast cells, but also enhanced osteoblast terminal differentiation (as early as 7 days in calcifying media).     

基于Cortex-M3的电池内阻检测系统设计与实现

以电池为能源的各类电气设备,在工业生产、交通、军事、通信等领域广泛应用,电池性能对电子、电气设备的正常运行具有极其重要的作用。电池在使用过程中,其性能和容量会随充放电次数的增加而下降,所以,定期维护及检验电池性能,是保证电器设备可靠工作的重要内容。电池内阻是检验电池性能和容量的重要参数,通过内阻检测评估电池性能和容量参数,也是科学研究和工业应用的基本原理。电池内阻测量的常用方法一般采用电位差原理。但是,该测量方法对于大型设备的高容量电池存在测量误差大、发热、易损电池等弊端。本文采用基于Cortex-M3核32位微处理微计算机控制和电位差原理的智能内阻测量系统,实现了大容量电池的精确、快速、安全测量和高度智能化的故障诊断功能,具有重要的科学研究意义及实用价值。