人工气候室监控系统的环境控制器研究

根据集散型控制系统(DCS)的技术特点,结合集散型人工气候室监控系统的需求,研究并实现了一种基于STC89C54RD+单片机的人工气候室环境控制器;为了充分利用STC89C54RD+单片机的片上资源,该控制器在无需外部扩展I/O的情况下实现了12路控制输出、8路开关量检测输入、5路A/D采集通道和1个RS-485通讯接口;为了增强系统的抗干扰能力,该控制器采用V/F转换作为A/D转换的主要手段并在各个前、后向通道上采取了三极管和光电耦合器相结合的双重隔离措施;为了提高控制器的灵活性和降低系统的整体开发成本,该控制器还提供了一种同时兼容热电阻、湿敏电阻等传感器和电流、电压型集成传感器的解决方案。     

高/低通复合多通道系统辨识的测试信号设计

从频域的角度研究了二进制多频序列(Muhifrequency Binary Sigal).从该信号的基本特点入手,通过对信号变化疏密的设计,调整信号的频谱分布.当已知待测系统的频谱集中在某些频段时,选取适当的二进制多频序列信号,能使测试信号的频谱也集中在那些频段,能充分地利用测试信号.大大提高了信噪比.设计出高频和低频复合的二进制多频序列信号.应用于一个通道是高通的,另一个通道是低通的二输入系统,能同时充分激励2个通道,取得较好的辩识效果.仿真算例可以看出有效性.     

一种基于完全独立集的排课算法

班级、教师、课程、教室、时间是课表的基本要素,通过把排课转化为求图的完全独立集,解决了时间冲突问题和合班课问题;根据教室资源限制,对独立集的个数和大小进行控制,解决了教室完全匹配问题和一门课程的不同教室安排问题.为实现排课软件提供了一个面向实际的算法.     

基于可拓学的动态网络专家系统研究与实现

构造Internet上的专家系统对扩大知识的共享范围具有重要意义。本文提出的一种基于可拓学的,使用Java开发方法,基于B/S程序架构,使得基于Web的专家系统能够充分发挥Java的高移植性、高扩展性的特点,而且可以发挥可拓规则的扩展性,以及动态性的特点。     

Editorial: Machine Learning and Intelligent Communications (MLICOM 2018)

Mobile Networks and Applications -     

Stubborn state estimation for complex-valued neural networks with mixed time delays: the discrete time case

Neural Computing and Applications - In this paper, the state estimation problem is investigated for a class of discrete-time complex-valued neural networks (CVNNs) with mixed time delays. We...     

卫星USB测控副载波同步算法研究

吉林一号卫星测控采用USB测控体制,遥控接收采用FFT+DPLL1+DPLL2的架构,FFT主要实现对载波的粗捕,DPLL1在FFT的基础上实现对载波相位的精跟踪,DPLL2实现副载波的跟踪。对遥控副载波跟踪所用到的数字PLL技术进行了研究,首先给出了载波多普勒折算到副载波上的方法,然后对模拟PLL数字化进行了详细的论述,并设计了遥控副载波同步用的PLL2,对其稳定性、快捕带及快捕时间、捕获带和捕获时间、同步速率等进行了分析和仿真。结果表明,该方法具有捕获时间短、跟踪精度高、稳定性好等特点,易于数字化实现,已成功在吉林一号系列卫星中得到应用。     

Hollow Pd/MOF Nanosphere with Double Shells as Multifunctional Catalyst for Hydrogenation Reaction

A new type of hollow nanostructure featured double metal‐organic frameworks shells with metal nanoparticles (MNPs) is designed and fabricated by the methods of ship in a bottle and bottle around the ship. The nanostructure material, hereinafter denoted as Void@HKUST‐1/Pd@ZIF‐8, is confirmed by the analyses of photograph, transmission electron microscopy, scanning electron microscopy, powder X‐ray diffraction, inductively coupled plasma, and N₂ sorption. It possesses various multifunctionally structural characteristics such as hollow cavity which can improve mass transfer, the adjacent of the inner HKUST‐1 shell to the void which enables the matrix of the shell to host and well disperse MNPs, and an outer ZIF‐8 shell which acts as protective layer against the leaching of MNPs and a sieve to guarantee molecular‐size selectivity. This makes the material eligible candidates for the heterogeneous catalyst. As a proof of concept, the liquid‐phase hydrogenation of olefins with different molecular sizes as a model reaction is employed. It demonstrates the efficient catalytic activity and size‐selectivity of Void@HKUST‐1/Pd@ZIF‐8.     

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.