基于亚微米光栅透射共振蛋白质检测模型研究

建立了一种基于亚微米光栅透射共振理论的蛋白质检测模型,设计了一种金属光栅型蛋白质检测生物传感器,运用光栅耦合激发表面等离子体共振理论对提出的模型进行了理论分析,通过计算机计算模拟,分析了蛋白质样品折射率、厚度等对透射率的影响。结果表明:透射率与样品折射率、厚度呈二阶多项式关系,并且厚度、折射率都随灵敏度的增加而增加。这种检测模型可应用在蛋白质检测传感方面。基于此方法的蛋白质检测模型具有同时检测蛋白质种类和含量、灵敏度高、实时、无需标记,便于集成芯片化,适用于批量生产、成本低等优点,在蛋白质芯片、生物分析、环境监测、生物器件研发等方面具有广泛的应用前景。     

Characterization of fish schooling behavior with different numbers of Medaka (Oryzias latipes) and goldfish (Carassius auratus) using a Hidden Markov Model

Fish that swim in schools benefit from increased vigilance, and improved predator recognition and assessment. Fish school size varies according to species and environmental conditions. In this study, we present a Hidden Markov Model (HMM) that we use to characterize fish schooling behavior in different sized schools, and explore how school size affects schooling behavior. We recorded the schooling behavior of Medaka (Oryzias latipes) and goldfish (Carassius auratus  ) using different numbers of individual fish (10–40), in a circular aquarium. Eight to ten 3 s video clips were extracted from the recordings for each group size. Schooling behavior was characterized by three variables: linear speed, angular speed, and Pearson coefficient. The values of the variables were categorized into two events each for linear and angular speed (high and low), and three events for the Pearson coefficient (high, medium, and low). Schooling behavior was then described as a sequence of 12 events (2×2×3$2\times 2\times 3$), which was input to an HMM as data for training the model. Comparisons of model output with observations of actual schooling behavior demonstrated that the HMM was successful in characterizing fish schooling behavior. We briefly discuss possible applications of the HMM for recognition of fish species in a school, and for developing bio-monitoring systems to determine water quality.     

Time-varying human mobility patterns with metapopulation epidemic dynamics

In this paper, explicitly considering the influences of an epidemic outbreak on human travel, a time-varying human mobility pattern is introduced to model the time variation of global human travel. The impacts of the pattern on epidemic dynamics in heterogeneous metapopulation networks, wherein each node represents a subpopulation with any number of individuals, are investigated by using a mean-field approach. The results show that the pattern does not alter the epidemic threshold, but can slightly lower the final average density of infected individuals as a whole. More importantly, we also find that the pattern produces different impacts on nodes with different degree, and that there exists a critical degree _kc$k_c$. For nodes with degree smaller than _kc$k_c$, the pattern produces a positive impact on epidemic mitigation; conversely, for nodes with degree larger than _kc$k_c$, the pattern produces a negative impact on epidemic mitigation.     

WALL CONDUCTION EFFECT ON THE ONSET OF THERMAL INSTABILITY IN HORIZONTAL RECTANGULAR CHANNELS

The effect of peripheral thermal conduction in the bottom wall on the onset of thermal instability in the thermal entrance region of horizontal, rectangular, bottom-uniform-heated channels was studied by experiment and theoretical simulation. The predicted results of the onset of thermal instability for the cases of uniform peripheral wall heat flux are in agreement with the published experimental data, but the predicted results for the cases of uniform peripheral wall temperature exceed the previous data by about an order of magnitude. The present experimental data reconfirm the present predictions. The effect of increasing the peripheral wall conduction is shown to stabilize the flow.     

Multi-agent system model with mixed coupling topologies for pattern formation and formation splitting

In this article, a new type of multi-agent system model with mixed coupling topologies is proposed for realizing pattern formations with specific geometric shapes and formation splitting. The interactions among individual agents are assumed to be universally repulsive and selectively attractive. By designing the form of attractive coupling matrix, one can obtain a variety of formations with specific shapes in the system through self-assembly of agents. Both symmetric coupling case and asymmetric coupling case are considered. Analysis and simulation results show symmetric ones result in convergent dynamics to steady-state formations, whereas, for asymmetric case, the system exhibits complex dynamic behaviours, including collective rotation and chaotic motion. By breaking the graph defined by attractive couplings into disjoint subgraphs, one can make the formation of agents to split into small sizes. The results are relevant for the design of coordination and cooperative control for multi-agent systems.     

一种改进的宽零陷天线方向图合成方法

在自适应阵列天线抗干扰的一些应用环境中 ,往往需要天线方向图在干扰的到达方向上形成宽的零陷以增强算法的稳健性。该文对一种宽零陷天线方向图合成方法进行了研究 ,提出了通过对零点矩阵加权处理 ,使不同干扰方向上的零点深度可以分别调节的改进方法 ,降低了方向图的畸变程度。计算机仿真结果证明了改进的效果     

基于模糊三值模式的矿物浮选泡沫图像边缘检测方法

针对一类边缘特征不明显的矿物浮选泡沫图像,提出了一种基于模糊三值模式的泡沫图像边缘检测方法.在‘0/1’二值模式基础上,增加不确定逻辑状态,构成模糊局部三值模式,以描述邻域像素灰度均值的不确定关系,同时,对邻域双向灰度差值之和进行模糊化,以描述边缘与非边缘方向的关系,联立邻域灰度关系与双向灰度差值隶属度,构造气泡边缘隶属度矩阵,依据联合隶属度的解模糊结果判决是否为边界候选像素,再根据边界候选像素集合的特征剔除非边界像素,以此得到泡沫边缘.实验结果表明,该方法能够有效地检测出气泡边缘,同时,在强噪声环境下,具有良好的鲁棒性.     

阵列波导光栅解调系统光电集成中Si纳米线AWG的设计

设计了一种阵列波导光栅解调集成系统中的8通道Si纳米线阵列波导光栅波分复用器。根据材料的折射率设计了单模波导截面尺寸,利用光束传播法对所设计阵列波导光栅进行了模拟。结果表明,器件尺寸为200μm×219μm,远小于目前技术较成熟的硅基SiO2的尺寸,光功率分布符合高斯分布,信道间隔为1.8nm,串扰小于-21dB。对小尺寸AWG的设计具有参考意义。