Flow Regime Identification of Gas-liquid Two-phase Flow Based on HHT

A new method to identify flow regime in two-phase flow was presented, based on signal processing of differential pressure using Hilbert Huang transform （HHT）. Signals obtained from a Venturi meter were decomposed into different intrinsic mode functions （IMFs） with HHT, then the energy fraction of each intrinsic mode and the mean value of residual function were calculated, from which the rules of flow regime identification were summarized. Experiments were carried out on two-phase flow in the horizontal tubes with 50mm and 40mm inner diameter, while water flowrate was in the range of 1.3m^3.h^-1 to 10.5m^3.h^-1, oil flowrate was from 4.2m^3.h^-1 to 7.0m^3.h^-1 and gas flowrate from 0 to 15m^3.h^-1. The results show that the proposed rules have high precision for single phase, bubbly, and slug, plug flow regirne identification, which are independent of not only properties of two-phase fluid. In addition, the method can meet the need of industrial application because of its simple calculation.

Totally Coded Method for Signal Flow Graph Algorithm

After a code-table has been established by means of node association information from signal flow graph, the totally coded method (TCM) is applied merely in the domain of code operation beyond any figure-earching algorithm. The code-series (CS) have the holo-information nature, so that both the content and the sign of each gain-term can be determined via the coded method. The principle of this method is simple and it is suited for computer programming. The capability of the computer-aided analysis for switched current network (SIN) can be enhanced.

Novel non-coherent integration method using binary phase-coded radar signal

The m series with 511 bits is taken as an example being applied in non-coherent integra- tion algorithm. A method to choose the bi-phase code is presented, which is 15 kinds of codes are picked out of 511 kinds of m series to do non-coherent integration. It is indicated that the power in- creasing times of larger target sidelobe is less than the power increasing times of smaller target main- lobe because of the larger target＇ s pseudo-randomness. Smaller target is integrated from larger tar- get sidelobe, which strengthens the detection capability of radar for smaller targets. According to the sidelobes distributing characteristic, a method is presented in this paper to remove the estimated sidelobes mean value for signal detection after non-coherent integration. Simulation results present that the SNR of small target can be improved approximately 6. 5 dB by the proposed method.

Initial orbit determination of BDS-3 satellites based on new code signals

For the two newly launched satellites(PRN number 27 and 28) of the future global BeiDou navigation satellite system(BDS-3), there is no available broadcast ephemeris data and other initial orbit information, but the initial orbit is the fundamental of the comprehensive analysis of the satellites and their signals. Precise orbit determination(POD) also requires determination of a priori initial value with a certain precision in order to avoid problems such as filter divergence during POD. Compared with the Newton iteration method, which relies on the initial value, this study utilizes the Bancroft algorithm to directly solve the nonlinear equations with the advantage of numerical stability. The initial orbits of these two satellites are calculated based on new code signals, and their results are analyzed and discussed. The experimental results show that, with the exception of very few epochs, when the new code signal is utilized, the median and robust variance factor of the observed residuals computed using pseudo-range observations and the solved initial orbits are less than 4 and 2 m, respectively. It also shows that this solution can be used for rapid initial orbit recovery after maneuvers of the new BeiDou satellites.

Implementation of a kind of FPGA-based binary phase coded radar signal processor architecture

A flexible field programmable gate array based radar signal processor is presented. The radar signal processor mainly consists of five functional modules： radar system timer, binary phase coded pulse compression（PC）, moving target detection （MTD）, constant false alarm rate （CFAR） and target dots processing. Preliminary target dots information is obtained in PC, MTD, and CFAR modules and Nios I! CPU is used for target dots combination and false sidelobe target removing. Sys- tem on programmable chip （SOPC） technique is adopted in the system in which SDRAM is used to cache data. Finally, a FPGA-based binary phase coded radar signal processor is realized and simula- tion result is given.

Recognition Method Based on Wigner-Hough Transform for Poly-Phase Code Radar Signal

In order to solve the recognition of polyphase code radar signal, this paper gives two methods based on Frank code, i.e. the high-order spectrum recognition method and the fractional Fourier transform (FRFT) method, by analyzing the micro characteristics of polyphase code signals in time and frequency domain respectively. And a recognition algorithm based on Wigner-Hough transform (WHT) is developed in this paper. We verify the validity of each method by computer simulation and give relative merits and demerits. A set of results demonstrate that the algorithm based on Wigner-Hough transform has better recognition performance in low signal-to-noise (SNR) than others.

Efficient practical codebook-precoding MIMO scheme based on signal space diversity

A novel practical codebook-precoding multiple-input multiple-output（MIMO） system based on signal space diversity（SSD） with the minimum mean squared error（MMSE）receiver is proposed.This scheme utilizes rotation modulation and space-time-frequency component interleaving.A novel precoding matrix selection criterion to maximize the average signal to interference plus noise ratio（SINR） is also put forward for the proposed scheme,which has a larger average mutual information（AMI）.Based on the AMI- maximization criterion,the optimal rotation angles for the proposed system are also investigated.The new scheme can make full use of space-time-frequency diversity and signal space diversity,and exhibit high spectral efficiency and high reliability in fading channels.Simulation results show that the proposed scheme greatly outperforms the conventional bit- interleaved coded modulation（BICM） MIMO-orthogonal frequency division multiplexing（OFDM） scheme without SSD,which is up to4.5 dB signal-to-noise ratio（SNR） gain.

Polyphase coded signal design for MIMO radar using MO-MicPSO

A novel modified optimization technique known as the multi-objective micro particle swarm optimization（MO-MicPSO） is proposed for polyphase coded signal design.The proposed MO-MicPSO requires only a small population size compared with the standard particle swarm optimization that uses a larger population size.This new method is guided by an elite archive to finish the multi-objective optimization.The orthogonal polyphase coded signal（OPCS） can fundamentally improve the multiple input multiple output（MIMO） radar system performance,with which the radar system has high resolution and abundant signal channels.Simulation results on the polyphase coded signal design show that the MO-MicPSO can perform quite well for this high-dimensional multi-objective optimized problem.Compared with particle swarm optimization or genetic algorithm,the proposed MO-MicPSO has a better optimized efficiency and less time consumption.

Finite rate of innovation sparse sampling for a binary frequency-coded ultrasonic signal

To achieve sparse sampling on a coded ultrasonic signal,the finite rate of innovation(FRI)sparse sampling technique is proposed on a binary frequency-coded(BFC)ultrasonic signal.A framework of FRI-based sparse sampling for an ultrasonic signal pulse is presented.Differences between the pulse and the coded ultrasonic signal are analyzed,and a response mathematical model of the coded ultrasonic signal is established.A time-domain transform algorithm,called the high-order moment method,is applied to obtain a pulse stream signal to assist BFC ultrasonic signal sparse sampling.A sampling of the output signal with a uniform interval is then performed after modulating the pulse stream signal by a sampling kernel.FRI-based sparse sampling is performed using a self-made circuit on an aluminum alloy sample.Experimental results show that the sampling rate reduces to 0.5 MHz,which is at least 12.8 MHz in the Nyquist sampling mode.The echo peak amplitude and the time of flight are estimated from the sparse sampling data with maximum errors of 9.324%and 0.031%,respectively.This research can provide a theoretical basis and practical application reference for reducing the sampling rate and data volume in coded ultrasonic testing.

外泌体来源非编码RNA对骨关节炎微环境的作用及临床应用进展

背景:骨关节炎是一种常见的关节退行性疾病,其发生发展的病因学机制尚不清楚。早期骨关节炎的及时诊治十分重要,目前尚无确切有效的方法。外泌体来源广泛,其中包含非编码RNA(Non-coding RNAs,ncRNAs),如微小RNAs、环状RNAs和长链非编码RNAs。外泌体ncRNAs可直接从原始细胞递送至邻近或远程细胞,通过细胞间通讯调节细胞活性,在重塑骨关节微环境中具有重要的调控作用。目的:总结外泌体来源ncRNAs对骨关节炎关节内微环境的干预作用,以及在临床应用中取得的进展,阐明其在骨关节炎诊治方面的潜力。方法:以“exosomes,non-coding RNA,osteoarthritis,application,signal pathway,synovial fluid,cartilage cells,cartilage matrix,subchondral bone,mechanism”为检索词在PubMed数据库中进行检索,最终纳入66篇相关文献进行综述分析。结果与结论:①外泌体来源ncRNAs在骨关节炎的发病过程中对关节内微环境具有重要调控作用,主要体现在外泌体ncRNAs调控关节内炎症反应、软骨细胞及软骨基质的退化,软骨下骨重塑和细胞间通讯。②外泌体中的ncRNAs可以作为骨关节炎的生物标志物,帮助骨关节炎的早期诊断和监测疾病进展与预后。③外泌体ncRNAs可作为骨关节炎的治疗靶点,外泌体携带miRNAs递送到关节的软骨细胞及软骨基质,发挥调控作用。④外泌体ncRNAs可以通过调控基因表达、促进细胞间通讯,提高软骨组织工程的效果,修复或再生受损软骨。⑤未来研究者应继续发掘外泌体来源ncRNAs对骨关节炎的干预机制,并可结合最新软骨组织工程的研究成果应用到临床之中,这将有效帮助解决骨关节炎患者的病痛。

基于空时分组/混沌编码的多天线多基频通信编码研究

为了优化空时分组编码(STBC)和混沌编码,提升无线通信的性能与可靠性,采用多基频混沌编码(MFCC)结合空时分组编码技术搭建了一种双重编码模型,并对该模型的编码解码性能进行仿真分析,评估模型的编码解码性能。实验结果显示,当信噪比为10 dB时,新模型的误码率低至10-8,并且能在两基频条件下实现3548 b/s的高吞吐量。表明该编码解码模型不仅能降低误码率,还能有效提高基频的吞吐量,为促进无线通信技术的发展提供了有力支持。

LINC01410促进食管鳞状细胞癌细胞增殖和迁移的作用及其机制研究

背景与目的:LINC01410是长度为647 bp的长链非编码RNA(long non-coding RNA,lncRNA),其异常表达参与多种肿瘤的发生、发展,但其对食管鳞状细胞癌(esophageal squamous cell carcinoma,ESCC)的影响研究较少。本研究旨在探讨LINC01410促进ESCC细胞增殖和迁移的作用机制,以期为防治ESCC提供生物标志物及潜在治疗靶点。方法:应用基因表达谱交互分析2(Gene Expression Profiling Interactive Analysis 2,GEPIA2)在线分析LINC01410在肿瘤与癌症基因组图谱(The Cancer Genome Atlas,TCGA)ESCC数据中的表达水平及与患者预后总生存期的关系;采用基因探针富集分析(Gene Set Enrichment Analysis,GSEA)LINC01410可能调控的信号转导通路。收集2020年1月—2021年12月在新乡医学院第一附属医院、平顶山市第一人民医院胸外科行根治性手术的ESCC患者新鲜肿瘤组织标本62例,并选取癌旁组织作为对照。本项目经医院伦理委员会批准(新乡医学院第一附属医院,编号:2018036;平顶山市第一人民医院,编号:2019-018)。本研究采用实时荧光定量聚合酶链反应(real-time fluorescence quantitative polymerase chain reaction,RTFQ-PCR)检测LINC01410的表达水平并分析其与临床病理学参数的关系。应用LV-NC、LV-over/LINC01410转染EC109细胞并建立稳定过表达细胞株EC109/NC、EC109/OE,采用shRNA-NC、shRNA-LINC01410转染EC9706细胞并建立稳定敲降细胞株EC9706/NC、EC9706/KD;应用RTFQ-PCR检测LINC01410的相对表达量;采用噻唑蓝比色法[3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide,MTT]实验和克隆形成实验检测细胞增殖;采用transwell实验检测细胞迁移能力;采用双荧光素酶报告基因实验检测LINC01410对T细胞因子/淋巴增强因子1(T cell factor/lymphoid enhancer factor 1,TCF/LEF1)启动子活性的影响;采用蛋白质印迹法(Western blot)检测Wnt/β-连环蛋白(β-catenin)信号转导通路、上皮-间质转化(epithelial-mesenchymal transition,EMT)信号转导通路相关蛋白表达水平。结果:GEPIA2分析显示,在ESCC组织中LINC01410表达水平显著高于食管正常组织,两组相比差异有统计学意义(P<0.05)。生存分析显示,高表达LINC01410的ESCC患者生存率显著低于低表达LINC01410的患者(P=0.042)。RTFQ-PCR检测结果显示,在ESCC组织中LINC01410表达水平显著高于配对癌旁组织;LINC01410高表达与肿瘤浸润程度、淋巴结转移及TNM分期显著相关(P<0.01);与食管正常上皮细胞HEEC相比,LINC01410在EC109、EC9706细胞中显著高表达(P<0.05);LINC01410在EC109/OE细胞中显著高表达(P<0.01),而在EC9706/KD细胞中显著下调(P<0.01)。MTT结果显示,EC109/OE细胞48 h时细胞活性显著高于EC109/NC细胞(P<0.01);EC9706/KD细胞48 h时细胞活性显著低于EC9706/NC(P<0.01)。细胞克隆形成实验结果显示,与EC109/NC细胞相比,EC109/OE细胞克隆数显著增多;与EC9706/NC细胞相比,EC9706/KD细胞克隆数明显减少(P<0.01)。Transwell迁移实验结果显示,EC109/OE细胞株迁移的细胞数显著多于EC109/NC细胞(P<0.01),而EC9706/KD细胞迁移的细胞数显著少于EC9706/NC细胞(P<0.01)。GSEA分析显示,Wnt/β-catenin、EMT等信号转导通路显著富集在高表达LINC01410的ESCC组织中。双荧光素酶报告基因实验结果示,EC109/OE细胞中TCF/LEF1启动子活性显著高于EC109/NC细胞,EC9706/KD细胞中TCF/LEF1启动子活性显著低于EC9706/NC细胞(P<0.01)。Western blot检测结果显示,与EC109/NC细胞相比,EC109/OE细胞中E-cadherin蛋白表达下调,而N-cadherin、β-cantenin、cyclin D1、c-Myc等蛋白显著上调;与EC9706/NC细胞相比,E-cadherin蛋白表达上调,而N-cadherin、β-cantenin、cyclin D1、c-Myc等蛋白显著下调。结论:LINC01410具有促进ESCC细胞增殖和迁移的作用,其机制可能与激活EMT、Wnt/β-catenin等信号转导通路有关。

基于稀疏编码的复杂机械振动信号盲分离方法

复杂机械振动信号激励源较多,故源信号之间互为相关源,且较难满足统计独立特性,导致传统盲源分离方法分离效果不佳。对此,提出一种基于信号稀疏编码的机械振动信号盲分离方法。盲源分离的关键在于对混合矩阵的精确估计,然而机械振源中相关成分的存在严重影响混合矩阵的估计。对此,首先对观测信号进行短时傅里叶变换,增加信号稀疏性;然后利用稀疏编码筛选出具备直线聚类特性的时频观测点,利用K均值(K-means)聚类法找到聚类中心;最后利用所提筛选规则找到估计的混合矩阵,重构出源信号。通过对往复压缩机故障数据的分析,验证了所提方法有效性。

基于Barker码脉冲压缩技术的钢板多阵元Lamb波电磁超声换能器设计与优化

为了解决传统Barker码脉冲压缩技术受脉冲功率放大器额定参数(占空比,最大脉冲宽度等)限制而导致的脉冲压缩效果下降、检测速度降低等问题,提出一种基于Barker码脉冲压缩技术的多阵元Lamb波电磁超声换能器(EMAT)。建立了基于tone-burst信号激励-Barker码脉冲压缩技术的多阵元Lamb波EMAT检测过程的有限元模型,分析了永磁体的配置形式、阵元序列长度、激励信号周期数、曲折线圈匝数等因素对脉冲压缩后的主旁瓣比和主瓣宽度的影响,并进行了实验验证。结果表明:曲折线圈匝数为4和Barker码序列长度为13位的多阵元EMAT在配置3对外置永磁体后,其信噪比(SNR)可提高9.8 dB。综合考虑检测回波的空间分辨率和SNR,多阵元Lamb波EMAT最佳参数为:曲折线圈匝数为10、激励信号周期数为11、Barker序列为13位,并配置3对外置永磁体。

对瞬时测频干扰机理的研究

瞬时测频(instantaneous frequency measurement,IFM)接收机是电子侦察中非常重要的测频资源,其结构简单、灵敏度高、侦察频带宽、分辨率高,可以快速测定被测信号的频率,在现代电子战中得到广泛应用。基于IFM微波鉴相器在某一瞬间只能响应一个信号的特性,结合IFM工作原理,研究了一种新的(超过2个信号)对IFM干扰策略,并分析了干扰机理,通过模拟仿真对IFM的干扰效果进行了评估。仿真结果表明:多信号交叠可以对IFM系统产生明显的干扰效果,可以使得其无法测得正确频率,并错误地输出同时到达信号指示。

基于改进随机森林的高光谱激光雷达信号分选研究

高光谱激光雷达数据在频谱维度上具有很高的维度,包含大量的波段或频带,易出现忽视频谱带中有用信息的情况,进而导致高光谱激光雷达信号分选效果较差。为此,提出基于改进随机森林的高光谱激光雷达信号分选研究。首先,采用变分模态分解算法对高光谱激光雷达含噪信号展开去噪处理;然后,采用长短期记忆神经网络算法对去噪后的高光谱激光雷达信号展开特征提取,并利用自编码神经网络对提取的特征展开重构处理,以获取重构后的雷达信号特征;最后,采用随机森林算法根据高光谱激光雷达信号特征完成信号分选。实验结果表明,所提方法的SNR为30.648 dB,RMSE为0.1498,预测分选类别与实际分选类别几乎一致,分析时间始终未超过5 s,表明所提方法的分选性能较好,具有实用性。

长链非编码RNA与缺血性脑卒中后的神经免疫炎症及相关信号通路

背景:长链非编码RNA作为炎症反应的重要调节因子,可参与缺血性脑卒中后免疫-炎症-脑串扰机制,具有成为治疗缺血性脑卒中后神经功能障碍的潜能。目的:将长链非编码RNA作用神经胶质细胞参与缺血性脑卒中后神经免疫炎症级联反应的分子机制及其调控的相关信号通路进行分析总结,指出长链非编码RNA具有调节缺血性卒中后炎症的潜力。方法:以“ischemic stroke,long non-coding RNA,neuroinflammation,immune function,signal pathway,microglia,astrocytes,oligodendrocyte,mechanism”为检索词在PubMed数据库中进行检索,最终纳入63篇相关文献进行综述分析。结果与结论:①在缺血性脑卒中发生早期,神经细胞因缺血缺氧死亡激活大脑先天免疫应答,促进炎症因子的分泌,诱导血脑屏障损伤及一系列炎症级联反应的发生。②神经免疫炎症级联反应作为缺血性脑卒中的重要发病因素,已被证实严重影响缺血性脑卒中患者的预后,需要在发病早期及时抑制。③缺血性脑卒中后神经炎症通常诱导大量长链非编码RNA的异常表达,这些长链非编码RNA通过调节小胶质细胞、星形胶质细胞、少突胶质细胞的极化介导一系列神经-免疫-炎症串扰机制,发挥脑卒中后神经保护作用。④长链非编码RNA作为炎症反应的重要调节因子,通过调控核转录因子κB、长链非编码RNA-miRNA-mRNA轴、Rho-ROCK、MAPK、AKT及ERK等信号通路抑制缺血性脑卒中后神经免疫炎症级联反应,有效改善缺血性脑卒中后神经功能损伤。⑤大多数长链非编码RNA与缺血性脑卒中相互作用的实验研究中是基于大脑中动脉闭塞模型或者脑缺血再灌注损伤模型进行的,并未进行临床试验,所以关于长链非编码RNA是否可以安全应用到临床治疗中还有待进一步探索。⑥目前有关治疗缺血性脑卒中的药物有许多,但是通过组织工程技术应用长链非编码RNA及外泌体等移植技术治疗缺血性脑卒中的研究相对较少,还需进一步探索。⑦长链非编码RNA以其相对稳定性和高度特异性的特点成为治疗缺血性脑卒中的重要靶点。在未来的研究中应继续探索更多在缺血缺氧条件下发挥作用的炎性长链非编码RNA类型,以期为治疗缺血性脑卒中后神经炎症提供新的研究方向。

雏菊叶龙胆酮拮抗阿霉素诱导心肌损伤中差异表达lncRNA的筛选及分析

背景:有研究表明,长链非编码RNA(long non-coding RNA,lncRNA)在心脏疾病的发生和发展中发挥了重要作用,其是否参与雏菊叶龙胆酮拮抗阿霉素诱导的小鼠心脏损伤目前未见报道。目的:筛选雏菊叶龙胆酮改善阿霉素诱导心肌损伤小鼠心肌组织中差异表达的lncRNA,并对其进行生物信息学分析。方法:取48只C57小鼠,采用随机数字表法分为正常组、模型组、雏菊叶龙胆酮组和阳性药组,每组12只。模型组、雏菊叶龙胆酮组和阳性药组小鼠腹腔注射阿霉素,隔日一次,共8次;雏菊叶龙胆酮组和阳性药组在注射阿霉素的基础上分别灌胃给予雏菊叶龙胆酮悬浊液、卡托普利溶液,1次/d,连续给药21 d。给药结束后,进行心电图检查与心肌组织病理形态观察,同时对小鼠心肌组织进行高通量测序分析,筛选出差异表达的lncRNA,对差异表达的lncRNA进行靶基因预测,并对靶基因进行GO富集与KEGG信号通路分析。结果与结论:①模型组小鼠心电图ST段明显抬高,雏菊叶龙胆酮组小鼠心电图ST段抬高程度减轻;苏木精-伊红、Masson及天狼猩红染色显示,模型组小鼠心肌组织中心肌胞浆着色不均,颜色深浅不一,心肌纤维完整性及连续性较差,可见大量胶原纤维沉积;雏菊叶龙胆酮处理后小鼠心肌组织异常情况有所改善。②高通量测序分析结果显示,与模型组相比,雏菊叶龙胆酮组小鼠心肌组织识别出差异表达lncRNA共270个,其中表达上调的lncRNA有165个,表达下调的lncRNA有105个。结合实验结果与相关文献,最终获得3条LncRNA(NONMMUT149833.1、NONMMUT003237.2、ENSMUST00000219015)及4个相关mRNAs(Alas2、Igf2、Acta1、Cilp)。靶基因预测、GO富集与KEGG信号通路分析结果显示,雏菊叶龙胆酮处理后,心肌损伤小鼠心肌组织中差异表达的lncRNA可通过顺式(cis-)和/或反式(trans-)调控来调节其靶蛋白编码基因的表达,参与调控分子功能及生物过程等。③结果显示,雏菊叶龙胆酮可显著改善阿霉素诱导心肌损伤小鼠的心功能和部分lncRNA表达。

面向异构处理平台任务调度的麻雀优化算法

针对当前异构信号处理平台中各处理器任务数量分配不均衡、处理器性能发挥不完全以及系统运行效率低的问题,文中提出一种面向异构处理平台的麻雀优化算法。该算法利用了麻雀算法较强的全局寻优能力和麻雀种群内部的高效工作机制。在经典麻雀算法基础上,文中提出了符合任务调度的二进制异或编解码规则,将离散的任务分配方案映射为连续的麻雀位置信息。将处理器负载均衡指数作为适应度函数,选取每次迭代中的最优解;在麻雀遍历任务时,采用任务优先级分流排序策略。对通信密集型任务和计算密集型任务采取不同的计算式得到更符合任务特点的遍历顺序,生成随机任务图,并将所提算法同ICPA(Improved Critical Path Algortthm)算法进行对比。仿真结果表明,相比于ICPA算法,所提算法的负载均衡指数平均优化率为60%,各处理器负载情况更加均衡,能更好地发挥异构处理平台的整体效能。

多功能信号源系统设计与数据压缩方法研究

在智能电网的各种设备安全检测中,需要信号源模拟多种故障信号,重复配置大量试验参数。针对这一需求,设计了一个多功能及操作便捷的信号源系统。该信号源系统能够输出多路可调直流、交流信号,还可配置开入量、开出量信号进行状态序列试验,模拟多种运行故障;利用SQLite存取试验数据,可快速进行多种电气试验,提升检测效率;使用混合熵编码与提升格式的小波变换等算法对录波文件(COMTRADE格式)进行压缩,节省存储空间,较对比算法有更高的压缩比和更低的重构误差。经测试,系统能够实现用户自定义的信号调制,模拟电力系统多种故障信号,在工程现场应用取得了良好的效果。