基于卷积神经网络的5G蜂窝网络无线定位方法

5G蜂窝网络发展迅猛，其覆盖面积将逐渐增大，因此使用5G蜂窝网络进行定位是有研究潜力的研究方向。本文提出一种新的深度学习技术来实现高效、高精度和低占用的定位，以代替传统指纹定位过程中繁重的指纹库生成以及距离计算。该方法建立了一个特殊的卷积神经网络，并根据5G天线信号的接收信号强度指示、相位和到达角等特征量，选择合适的输入数据格式构造样本组建训练集，对该卷积神经网络进行训练。训练得到的卷积神经网络可以替代指纹定位中的庞大指纹库，非常有利于直接在5G移动设备端实现定位。虽然卷积神经网络在训练过程中需要大量时间，但在训练完毕后直接进行分类定位的速度非常快，可以保障定位实现的实时性。本文所实现的卷积神经网络权重与偏置所占内存不到0.5 MB，且能够在实际应用环境中以95%的定位准确率以及0.1 m的平均定位精度实现高精度定位。     

“数字信号处理”课程的几何视角

“数字信号处理”的经典课程体系以“系统”为中心，以离散时间傅立叶变换、z变换和离散傅立叶变换为分析工具，以滤波器设计为目的，注重定理和公式推导及其性质分析，很难让学生建立一个形象的、完整统一的知识体系框架。本文从几何视角将 “系统”化和“代数”化的经典课程体系重构为面向“信号”的“几何”知识体系，从而提升学生对本质问题的“洞察力”，帮助学生建立系统的知识体系。     

非径向管板焊接接头的超声检测

对AP1000压水堆核电站安全壳贯穿件的非径向管板焊接接头结构特点进行了介绍,并分析其超声检测工艺的重点和难点。通过建立统一的缺陷定位坐标系并结合被检构件的几何特点进行综合分析,推导得出了h值(缺陷回波最高点距套管外壁的距离)的计算方法。为超声检测对这类焊接接头缺陷的准确识别和定位提供了行之有效的方法,为解决这类焊接接头的超声检测技术受限区提供了行之有效的措施。     

Mechanisms of Reciprocal Regulation of Gonadotropin-Releasing Hormone (GnRH)-Producing and Immune Systems: The Role of GnRH,Cytokines and Their Receptors in Early Ontogenesis in Normal and Pathological Conditions

Different aspects of the reciprocal regulatory influence on the development of gonadotropin-releasing hormone (GnRH)-producing- and immune systems in the perinatal ontogenesis and their functioning in adults in normal and pathological conditions are discussed. The influence of GnRH on the development of the immune system, on the one hand, and the influence of proinflammatory cytokines on the development of the hypothalamic-pituitary-gonadal system, on the other hand, and their functioning in adult offspring are analyzed. We have focused on the effects of GnRH on the formation and functional activity of the thymus, as the central organ of the immune system, in the perinatal period. The main mechanisms of reciprocal regulation of these systems are discussed. The reproductive health of an individual is programmed by the establishment and development of physiological systems during critical periods. Regulatory epigenetic mechanisms of development are not strictly genetically controlled. These processes are characterized by a high sensitivity to various regulatory factors, which provides possible corrections for disorders.     

应用于光遗传学的集成式注入型生物光电极器件的研究进展

光遗传学是一门涉及神经科学、光学、半导体光电子学及生物医学的交叉科学.把光作为一种遗传学的研究工具,可为神经科学研究提供更高效、精准的神经调控手段,也为临床精神疾病的研究和治疗提供了新的思路.集成式注入型生物光电极是一种集刺激神经元的光源与采集生物电信号的微电极于一体的多功能生物微探针,在利用活体生物进行的光遗传学研究中有着重要的应用.文章回顾了光遗传学的历史,对集成式注入型生物光电极器件的分类和发展进行了分析,详细比较了不同类型光电极器件在结构和性能上的差异,从电学特性、噪声信号、生物兼容性及可靠性等方面进行评价.最后,对光电极器件的未来发展进行了初步的探讨.     

超声强化过氧化氢-维生素C体系糖汁脱色的研究

研究超声强化过氧化氢-维生素C复合脱色剂体系对糖汁脱色的规律,考察了超声功率、复合脱色剂用量、超声温度和时间对糖汁脱色率的影响。试验结果表明:超声空化强化过氧化氢-维生素C对糖汁具有良好的脱色效果,当处理糖汁量为100 mL,超声功率为260 W,过氧化氢与维生素C的用量均为1.6 mL,空化温度为70℃,超声时间为6 min时,脱色率达到53.4%。通过正交试验分析,得到各个因素对糖汁脱色率影响的主次关系为:超声功率>复合脱色剂用量>超声时间>空化温度。     

多铜氧化酶在大肠杆菌中的分泌表达

生物胺是存在于发酵食品中的一类有机物，过量摄入会危害人体健康。多铜氧化酶中的某些酶具有降解多种生物胺的活性，在减控发酵食品中的氨(胺)类危害物方面具有良好的应用前景。研究多铜氧化酶的分泌表达，对酶的特性改造和工业化生产与应用具有重要意义。本研究通过在解淀粉芽孢杆菌来源的多铜氧化酶N端融合信号肽PhoA实现了多铜氧化酶在大肠杆菌中的分泌表达，胞外酶活为69.8 U/L。通过优化诱导条件和酶的分泌确定了多铜氧化酶最优发酵条件为诱导温度25℃、IPTG浓度0.05 mmol/L、诱导时菌体OD600=1.0、诱导6 h后添加150 mmol/L甘氨酸；发酵40 h时胞外多铜氧化酶酶活达到238.1 U/L，是优化前的3.4倍。     

Sustainable progress into batchwise coloration of polyurethane nanofibers by using ultrasonic energy

Abstract

In this decade, aesthetic potentials of electrospun polymeric nanofibers for advanced apparels have been studied. For the first time, we studied the sustainable aspects in the batchwise dyeing process of electrospun polymeric nanofibers in terms of conserving thermal energy and reducing the wastewater pollution. The nanofibrous mats were prepared using polyurethane (PU) polymer followed by dyeing with disperse dyes by conventional (CN) dyeing method as well as ultrasonic (US)-assisted dyeing method. Potential of savings in thermal energy (1000?kcal), dwell time (40?min) and quantity of disperse dyes (1.5% on the mass of nanofibers) were realized during the US-assisted dyeing method in comparison with the CN dyeing method. Further, total dissolved solids (TDS) and chemical oxygen demand (COD) contents of dyeing effluents demonstrated considerable ecological merits of the US dyeing method in terms of 30% reduction in TDS and 46% reduction in COD contents in comparison with the CN dyeing method. Excellent color strength (K/S) (reached 10) of dyed PU nanofibrous mats were achieved by US-assisted dyeing method in comparison with the K/S (reached 6) with CN dyeing method. Attenuated total reflectance-Fourier transform infra-red (FTIR) spectroscopy, UV–Vis spectrophotometer and Scanning electron microscopy (SEM) analysis were also applied during the study for characterization.     

Traveling-wave Phenomena in a Model of Autocrine Signaling Coupled with Dynamics of the MAPK Cascade

Recently we have revealed a minimal reaction subnetwork in the MAPK (mitogen-activated protein kinase) cascade that is responsible for the emergence of bistable and oscillatory behavior. Here we examine a possible mechanism that provides for the propagation of increased MAPK activity in cell populations by interconnecting the intracellular MAPK subnetwork with the ligand-receptor signaling machinery. Such approach allows for significant reduction of the dimensionality of the parameter space on one hand and the conservation of dynamical complexity of the system on the other hand. The coupled model predicts coexistence of one, two or three different stable steady states, or the coexistence of a stable steady state and periodic solution. We found two robust and physiologically relevant characteristics of the proposed model: (i) There is a very large region of coexistence of at least one stable steady state with non-zero MAPK activity and one steady state with zero MAPK activity in the parameter space. (ii) Spontaneous traveling front waves always switching originally inactive cells into ligand releasing cells emerge in adjacent cell populations, e. g. in healthy and injured tissues. Moreover, the formation of composite traveling front waves and spatial oscillatory patterns of MAPK activity are predicted and discussed.     

基于全相位预处理的时域多重信号分类波达方向估计方法

低信噪比下,针对宽带短脉冲情况下频域多重信号分类(MUSIC)中噪声子空间估计不稳定问题,提出一种基于全相位预处理的时域多重信号分类波达方向(DOA)估计方法。①对线列阵接收数据进行分组处理;②按搜索角度对各组数据进行相移预处理,并对各组数据预处理结果进行相加,得到一组新数据;③对线列阵接收数据在时域构建相移后的协方差矩阵,在更短数据长度下,稳定实现噪声子空间估计,并依据估计出的噪声子空间含有的正交特性,通过单位矩阵加法器得到相应空间谱估计值,实现波达方向估计。数值仿真和实测数据处理结果表明,相比频域MUSIC方法,该方法有效提高了线列阵接收数据协方差矩阵中信号含有量和信噪比,能够在更短数据长度情况下实现对噪声子空间的稳定估计,具有较好的稳定性和检测性能,提高了MUSIC方法在实际波达方向估计中的鲁棒性。