A Novel Kind of Wideband Low-Profile Dielectric Resonator Antenna Suitable for Beam-scanning Applications

In this paper, a low-profile wideband dielectric resonator antenna(DRA) with a very compact planar size is investigated. The antenna consists of a high permittivity dielectric sheet on the top, a low permittivity substrate in the middle, and a probe feeding structure at the bottom. By digging an annular slot in the designated area of the square dielectric sheet, the resonant frequency of fundamental TE111 mode can be effectively increased to be close to the high-order TE131 mode. The two modes c...     

Domain Adaptation with Data Uncertainty Measure Based on Evidence Theory

Domain adaptation aims to learn a classifier for a target domain task by using related labeled data from the source domain. Because source domain data and target domain task may be mismatched, there is an uncertainty of source domain data with respect to the target domain task. Ignoring the uncertainty may lead to models with unreliable and suboptimal classification results for the target domain task. However, most previous works focus on reducing the gap in data distribution between the source and target domains. They do not consider the uncertainty of source domain data about the target domain task and cannot apply the uncertainty to learn an adaptive classifier. Aimed at this problem, we revisit the domain adaptation from source domain data uncertainty based on evidence theory and thereby devise an adaptive classifier with the uncertainty measure. Based on evidence theory, we first design an evidence net to estimate the uncertainty of source domain data about the target domain task. Second, we design a general loss function with the uncertainty measure for the adaptive classifier and extend the loss function to support vector machine. Finally, numerical experiments on simulation datasets and real-world applications are given to comprehensively demonstrate the effectiveness of the adaptive classifier with the uncertainty measure.     

SnAgCuY钎料表面Sn晶须的旋转生长现象

研究了Sn3.8Ag0.7Cu1.0Y钎料表层上YSn3稀土相表面Sn晶须的生长行为。结果表明:室温时效条件下在YSn3的表面会出现Sn晶须的快速生长现象,生长速度最快可达10–10m/s,长度最长可达200μm。YSn3稀土相氧化的不均匀性是导致Sn晶须在生长时产生各种旋转现象的主要原因。     

基于开源处理器Rocket的异构SoC设计与验证

随着神经网络隐层数的增多,训练计算量增大.为提高算法的执行效率,包含硬件算法加速器的异构片上系统(SoC)相继被提出.开源处理器Rocket core项目含有核生成器,不仅能够定制核的个数而且含有协处理扩展接口,易于异构SoC的研究和设计工作.基于开源处理器Rocket core和开源项目Si-Five Blocks,...     

In Vitro and In Vivo Antibacterial Activity,Toxicity and Resistance Analysis of Pleuromutilin Derivative Z33 against Methicillin-Resistant Staphylococcus aureus

The novel pleuromutilin derivative, which showed excellent in vitro antibacterial activity against MRSA, 22-(2-(2-(4-((4-(4-nitrophenyl)piperazin-1-yl)methyl)-1H-1,2,3-triazol-1-yl)acetamido)phenyl)thioacety-l-yl-22-deoxypleuromutilin (Z33), was synthesized and characterized in our previous work. In this study, the preliminary pharmacodynamics and safety of Z33 were further evaluated. In in vitro antibacterial activity assays, Z33 was found to be a potent bactericidal antibiotic against MRSA that induced dose-dependent growth inhibition and long-term post-antibiotic effect (PAE). The drug-resistance test demonstrated that Z33 possessed a narrow mutant selection window and lower propensities to select resistance than that of tiamulin. Cytochrome P450 (CYP450) inhibition assay determined that the inhibitory effect of Z33 was similar to that of tiamulin against the activity of CYP3A4, and was lower than that of tiamulin on the activity of CYP2E1. Toxicity determination showed that both Z33 and tiamulin displayed low cytotoxicity of RAW264.7 cells. Furthermore, Z33 was found to be a high-security compound with a 50% lethal dose (LD₅₀) above 5000 mg/kg in the acute oral toxicity test in mice. In an in vivo antibacterial activity test, Z33 displayed better therapeutic effectiveness than tiamulin in the neutropenic mouse thigh infection model. In summary, Z33 was worthy of further development as a highly effective and safe antibiotic agent against MRSA infection.     

An Exploration of the Effect of the Kleier Model and Carrier-Mediated Theory to Design Phloem-Mobile Pesticides Based on Researching the N-Alkylated Derivatives of Phenazine-1-Carboxylic Acid-Glycine

The Kleier model and Carrier-mediated theory are effective for molecularly designing pesticides with phloem mobility. However, the single Kleier model or Carrier-mediated theory cannot achieve a reliable explanation of the phloem mobility of all exogenous substances. A detailed investigation of the two models and the scope of their applications can provide a more accurate and highly efficient basis for the guidance of the design and development of phloem-mobile pesticides. In the present paper, a strategy using active ingredient-amino acid conjugates as mode compounds is developed based on Carrier-mediated theory. An N-alkylated amino acid is used to improve the pesticide’s physicochemical properties following the Kleier model, thus allowing the conjugates to fall on the predicted and more accessible transportation region of phloem. Moreover, the influence of this movement on phloem is inspected by the Kleier model and Carrier-mediated theory. To verify this strategy, a series of N-alkylated phenazine-1-carboxylic acid-glycine compounds (PCA-Gly) were designed and synthesized. The results related to the castor bean seeds (R. communis L.) indicated that all the target compounds (4a–4f) had phloem mobility. The capacity for phloem mobility shows that N-alkylated glycine containing small substituents can significantly improve PCA phloem mobility, such as 4c(i-C₃H₇-N) > 4a(CH₃-N) ≈ 4b(C₂H₅-N) > 4d (t-C₄H₉-N) > PCA-Gly > 4e(C₆H₅-N) > 4f(CH₂COOH-N), with an oil–water partition coefficient between 1.2~2.5. In particular, compounds 4a(CH₃-N), 4b(C₂H₅-N), and 4c(i-C₃H₇-N) present better phloem mobility, with the average concentrations in phloem sap of 14.62 μΜ, 13.98 μΜ, and 17.63 μΜ in the first 5 h, which are 8 to 10 times higher than PCA-Gly (1.71 μΜ). The results reveal that the Kleier model and Carrier-mediated theory play a guiding role in the design of phloem-mobile pesticides. However, the single Kleier model or Carrier-mediated theory are not entirely accurate. Still, there is a synergism between Carrier-mediated theory and the Kleier model for promoting the phloem transport of exogenous compounds. Therefore, we suggest the introduction of endogenous plant compounds as a promoiety to improve the phloem mobility of pesticides through Carrier-mediated theory. It is necessary to consider the improvement of physicochemical properties according to the Kleier model, which can contribute to a scientific theory for developing phloem-mobile pesticides.     

Cardiac-specific overexpression of Ndufs1 ameliorates cardiac dysfunction after myocardial infarction by alleviating mitochondrial dysfunction and apoptosis

Myocardial infarction (MI) is the leading cause of premature death among adults. Cardiomyocyte death and dysfunction of the remaining viable cardiomyocytes are the main pathological factors of heart failure after MI. Mitochondrial complexes are emerging as critical mediators for the regulation of cardiomyocyte function. However, the precise roles of mitochondrial complex subunits in heart failure after MI remain unclear. Here, we show that NADH:ubiquinone oxidoreductase core subunit S1 (Ndufs1) expression is decreased in the hearts of heart failure patients and mice with myocardial infarction. Furthermore, we found that cardiac-specific Ndufs1 overexpression alleviates cardiac dysfunction and myocardial fibrosis in the healing phase of MI. Our results demonstrated that Ndufs1 overexpression alleviates MI/hypoxia-induced ROS production and ROS-related apoptosis. Moreover, upregulation of Ndufs1 expression improved the reduced activity of complex I and impaired mitochondrial respiratory function caused by MI/hypoxia. Given that mitochondrial function and cardiomyocyte apoptosis are closely related to heart failure after MI, the results of this study suggest that targeting Ndufs1 may be a potential therapeutic strategy to improve cardiac function in patients with heart failure.Subject terms: Heart failure, Myocardial infarction, Myocardial infarction     

基于末端轨迹修正的导弹跟踪稳定性控制方法

舰载导弹在制导飞行的末端容易受到空气小扰动的影响产生轨迹偏离,需要进行轨迹偏离修正控制,提高弹道对目标跟踪的姿态稳定性,提出一种基于改进的扩展Kalman滤波(EKR)和误差反馈修正的导弹跟踪端轨迹修正控制方法.以陀螺仪采集的导弹的横滚角、俯仰角以及航向偏离的参量为控制约束指标集,采用扩展Kalman滤波算法进行姿态参量融合,结合Smith结构建立导弹跟踪控制的被控对象模型,计算末端轨迹中姿态角与真值的偏差,根据偏差进行导弹的惯性姿态反馈调节,采用自适应的量化融合跟踪识别方法进行导弹定姿处理,通过对末端轨迹的误差反馈修正提高姿态角的输出精度,根据姿态的不断变化实现自适应的位姿修正,实现导弹对敌目标跟踪的稳定性控制.仿真结果表明,采用该方法进行导弹控制的姿态角解算的误差较小,定姿精度较高,提高导弹跟踪控制的稳定性和鲁棒性.     

提高两点温度定标法精度的焦平面非均匀性校准技术研究

凝视红外成像系统中的探测器非均匀性校准(降低固有空间噪声)技术是一项处在探索过程中的关键技术.目前实用性较好的两点温度定标法的校准系数精度受读出噪声、信号动态范围、模数转换字长和运算噪声的限制,很难使焦平面探测器的空间残留噪声达到应有的精度.文中探索了一种二次参数补偿的两点温度定标方案,由基本公式得到的校准参数值,再依据现实信号动态范围进行实时精度补偿,使之更加接近于理论计算值,从而使非均匀性校准的系数精度得到较大幅度提高.这一方案可在不改变图像处理机硬件开销和软件运行负担的前提下完成对两点温度定标法精度的补偿.计算机仿真实验结果证明了该方法的有效性,可降低残留空间噪声50%以上.     

Dynamic sensor collaboration via sequential Monte Carlo

We consider the application of sequential Monte Carlo (SMC) methods for Bayesian inference to the problem of information-driven dynamic sensor collaboration in clutter environments for sensor networks. The dynamics of the system under consideration are described by nonlinear sensing models within randomly deployed sensor nodes. The exact solution to this problem is prohibitively complex due to the nonlinear nature of the system. The SMC methods are, therefore, employed to track the probabilistic dynamics of the system and to make the corresponding Bayesian estimates and predictions. To meet the specific requirements inherent in sensor network, such as low-power consumption and collaborative information processing, we propose a novel SMC solution that makes use of the auxiliary particle filter technique for data fusion at densely deployed sensor nodes, and the collapsed kernel representation of the a posteriori distribution for information exchange between sensor nodes. Furthermore, an efficient numerical method is proposed for approximating the entropy-based information utility in sensor selection. It is seen that under the SMC framework, the optimal sensor selection and collaboration can be implemented naturally, and significant improvement is achieved over existing methods in terms of localizing and tracking accuracies.