Clinical Value of the Quantitative Flow Ratio to Predict Long-term Target Vessel Failure in Patients with In-stent Restenosis after Drug-coated Balloon Angioplasty

Objective The study sought to investigate the clinical predictive value of quantitative flow ratio(QFR)for the long-term target vessel failure(TVF)outcome in patients with in-stent restenosis(ISR)by using drug-coated balloon(DCB)treatment after a long-term follow-up.Methods This was a retrospective study.A total of 186 patients who underwent DCB angioplasty for ISR in two hospitals from March 2014 to September 2019 were enrolled.The QFR of the entire target vessel was measured offline.The primary endpoint was TVF,including target vessel-cardiac death(TV-CD),target vessel-myocardial infarction(TV-MI),and clinically driven-target vessel revascularization(CD-TVR).Results The follow-up time was 3.09±1.53 years,and 50 patients had TVF.The QFR immediately after percutaneous coronary intervention(PCI)was significantly lower in the TVF group than in the no-TVF group.Multivariable Cox regression analysis indicated that the QFR immediately after PCI was an excellent predictor for TVF after the long-term follow-up[hazard ratio(HR):5.15×10−5(6.13×10−8−0.043);P<0.01].Receiver-operating characteristic(ROC)curve analysis demonstrated that the optimal cut-off value of the QFR immediately after PCI for predicting the long-term TVF was 0.925(area under the curve:0.886,95%confidence interval:0.834–0.938;sensitivity:83.40%,specificity:88.00;P<0.01).In addition,QFR≤0.925 post-PCI was strongly correlated with the TVF,including TV-MI and CD-TVR(P<0.01).Conclusion The QFR immediately after PCI showed a high predictive value of TVF after a long-term follow-up in ISR patients who underwent DCB angioplasty.A lower QFR immediately after PCI was associated with a worse TVF outcome.

A multi-directional controllable multi-scroll conservative chaos generator:Modelling,analysis,and FPGA implementation

Combing with the generalized Hamiltonian system theory,by introducing a special form of sinusoidal function,a class of n-dimensional(n=1,2,3)controllable multi-scroll conservative chaos with complicated dynamics is constructed.The dynamics characteristics including bifurcation behavior and coexistence of the system are analyzed in detail,the latter reveals abundant coexisting flows.Furthermore,the proposed system passes the NIST tests and has been implemented physically by FPGA.Compared to the multi-scroll dissipative chaos,the experimental portraits of the proposed system show better ergodicity,which have potential application value in secure communication and image encryption.

Flow Field and Thermal Analysis of the Divertor Target Plate for HL-2A Tokamak

In the initial phase of the physics experiment, the double-null divertor plates used consist of graphite armor tiles, Mo-alloy intermediate layers and Cu-alloy coolant tubes. In the later operating phase, tungsten will be used as armor tiles. A multi-physical field numerical analysis method is used in this paper. Its analysis model reflects more realistically the real divertor structure than other models. Two-dimensional （2D） and three-dimensional （3D） fluid flow field, temperature distribution and thermal stress analyses of the divertor plates are carried out by the ANSYS code. During the physics experimental phase with a heat flux of 1 MW/m2, a coolant velocity of 5.48 m/s, and a thermal stress of 750 kg/cm2, the graphite armor tiles successfully meet the requirements of temperature, thermal stress and sputtering erosion. The tungsten armor will be considered as a second candidate. The result of simulation can be used for upgrading the design parameters of the HL-2A poloidal divertor.

The law of anti-VCAM-1 targeted microbubbles adhesion to activated endothelial cells under controlled shear flow

Microbubbles can enhance the detection in noninvasive ultrasound imaging.Recently,targeted microbubbles have been developed to selectively adhere to specific and overexpressed p molecules in endothelial cells in some pathologic conditions.However,the law of

5-7 Geometrical Research on the Flow Rate of the Gravity-driven Dense Granular Flow Target

Following previous designs such as plate targets, rod targets, rotating targets and liquid metal targets, the gravity-driven dense granular-flow target (DGT), which combines the advantages of solid and liquid metal targets,becomes a new attractive choice[1]. The geometry of DGT consists of a cylindrical hopper and an internal coaxial cylindrical beam pipe as shown in Fig. 1. Using discrete element method (DEM) simulations on GPUs, we research into the relations of the flow rate with the geometrical parameters.

Analysis of the Flow Field and Impact Force in High-Pressure Water Descaling

This study aims to improve the performances of the high-pressure water descaling technology used in steel hot rolling processes.In particular,a 2050 mm hot rolling line is considered,and the problem is investigated by means of a fluid–structure interaction(FSI)method by which the descaling effect produced by rolling coils with different section sizes is examined.Assuming a flat fan-shaped nozzle at the entrance of the R1R2 roughing mill,the outflow field characteristics and the velocity distribution curve on the strike line(at a target distance of 30–120 mm)are determined.It is found that the velocity in the center region of the water jet with different target distances is higher than that in the boundary region.As the target distance increases,the velocity of the water jet in the central region decreases.Through comparison with experimental results,it is shown that the simulation model can accurately predict the impact position of the high-pressure water on the impact plate,thereby providing a computational scheme that can be used to optimize the nozzle space layout and improve the slabs’descent effect for different rolling specifications.

A Normalizing Flow-Based Bidirectional Mapping Residual Network for Unsupervised Defect Detection

Unsupervised methods based on density representation have shown their abilities in anomaly detection,but detection performance still needs to be improved.Specifically,approaches using normalizing flows can accurately evaluate sample distributions,mapping normal features to the normal distribution and anomalous features outside it.Consequently,this paper proposes a Normalizing Flow-based Bidirectional Mapping Residual Network(NF-BMR).It utilizes pre-trained Convolutional Neural Networks(CNN)and normalizing flows to construct discriminative source and target domain feature spaces.Additionally,to better learn feature information in both domain spaces,we propose the Bidirectional Mapping Residual Network(BMR),which maps sample features to these two spaces for anomaly detection.The two detection spaces effectively complement each other’s deficiencies and provide a comprehensive feature evaluation from two perspectives,which leads to the improvement of detection performance.Comparative experimental results on the MVTec AD and DAGM datasets against the Bidirectional Pre-trained Feature Mapping Network(B-PFM)and other state-of-the-art methods demonstrate that the proposed approach achieves superior performance.On the MVTec AD dataset,NF-BMR achieves an average AUROC of 98.7%for all 15 categories.Especially,it achieves 100%optimal detection performance in five categories.On the DAGM dataset,the average AUROC across ten categories is 98.7%,which is very close to supervised methods.

基于FlowNet2.0网络的目标光流检测方法

针对传统光流法存在鲁棒性不高、易对图像噪声敏感、实时性差等问题,提出了一种基于FlowNet2.0网络的目标光流检测方法。将相邻两帧图像输入基于Caffe学习框架的FlowNet2.0网络,让其在光流网络堆叠结构中进行相关卷积操作学习光流;接着对卷积神经网络前向反馈的梯度进行优化降低损失率,让其自适应地训练目标;最后融合光流模型实现预测光流图。FlyingChairs数据集的实验表明,相比于传统目标光流检测算法,本文方法在目标光流场检测中具有较好的实时性和自适应性。

基于ATCA平台FC Target的设计与实现

在Linux环境下,以先进的计算平台ATCA为基础,通过编写目标端接口函数,完成FC Target端的设计与实现,并详细介绍了FC Target端的读命令和写命令的处理流程。通过对比测试,验证了FC Target在ATCA环境下性能稳定,数据传输效率高。

Flow Cytometer Performance Characterization, Standardization and Calibration against CD4 on T Lymphocytes Enables Quantification of Biomarker Expressions for Immunological Applications

There is an urgent need for developing a procedure for biomarker standardization and relative quantificationin clinical laboratories. Measuring the expression levels of cell antigens is critical for the diagnosis of many diseases, e.g. leukemia, lymphoma and immunodeficiency diseases. One of the most significant challenges in flow cytometry is obtaining inter-laboratory and intra-laboratory consistent and reproducible results across multiple cytometer platforms and locations longitudinally over time. To obtain measurement consistency, the target flow cytometer voltages should be optimized to segregate the negative population from the electronic noise, and to keep the brightest positive population within the dynamic range of each detector. Then target values should be determined and transferred to selected cytometers. In this study, we optimized a procedure for instrument standardization across three different flow cytometer platforms from the same vendor and in two different locations. The biomarker quantification was implemented on standardized instruments using CD4 expression on T lymphocytes with a known amount of antibody bound per cell as a quantification standard. Our results on blood cell subset typing and CD19 quantification demonstrated that consistent and reliable results could be accomplished between instruments using the developed procedure. Quantitating the expression levels of certain cell biomarkers relative to a known reference marker before, during, and after therapy would provide important information for monitoring antibody-based therapy and could be potentially used to adjust dosing. Presently, we are implementing this protocol to quantify critical disease biomarkers, and making necessary modifications to the procedure to include instruments from different instrument manufacturers.

经济增长目标调整促进了资本流动吗——基于企业跨地区投资的视角

地方政府“为增长而竞争”的发展模式是造成市场分割的重要因素,那么经济增长目标下调能否缓解这一局面、促进要素资源自由流通?为了回答这一问题,本文以上市公司在异地设立子公司的行为衡量资本要素的流动性,系统考察经济增长目标下调对企业跨地区投资的影响。研究发现,经济增长目标下调能够促进资本流动,表现为经济增长目标下调显著提升了辖区内上市公司设立异地子公司的比例;影响机制分析表明,经济增长目标下调提高了政府放权意愿,降低了市场分割程度,进而促进了企业跨地区投资;进一步的异质性分析揭示,在地区行政壁垒较低、行业竞争程度较高及民营企业样本中,经济增长目标下调对企业跨地区投资的促进作用更加明显。本文丰富了制度性政府行为影响资源配置的相关研究,为当前推进全国统一大市场建设提供了直接的政策思路。

基于视频的振动测量技术研究进展

振动测量是保障结构安全和良好状态的基本手段。高精度的振动测量可为结构设计、安装调试、健康管理等振动试验提供精确的输入与响应测试。相较于传统的振动测量手段,基于视频的振动测量技术将相机的全部像素转化为高精度振动传感器,利用视频图像方式让人们肉眼可视结构在物理世界的真实振动形态,具有非接触、全视场、高空间分辨率、灵活方便等优点,近年来受到业界的广泛关注。该文主要介绍了视频振动测量技术的系统构成与测量过程、当前主要方法和相关技术最新进展,并总结了视频振动测量技术与其他技术相比存在的优势。通过分析与对比,肯定了视频方法是解决振动测量问题的有效手段和对传统测量方法的有力补充,随着相关技术和硬件设备的发展,视频振动测量方法将具有越来越大的研究意义和应用价值。

基于YOLO模型的车流量实时采集系统研究

对于一座现代化城市来说,合理的交通规划是一个城市高效运行的关键,作为交通规划的关键信息的城市车流量信息,原本需要人工进行识别、获取、验证的提取方式,随着计算机视觉技术的蓬勃发展弊端尽显,终将退出历史的舞台。为了提高城市车流量信息的准确性和及时性,利用现有的计算机技术设计一种基于YOLO模型的车流量实时采集系统。该系统基于YOLO视觉检测模型,采用DeepSORT算法对检测到的目标车辆进行跟踪识别、判断车辆的运行状态、实现当前路段的车流量统计、对已记录车流量信息进行可视化展示以及数据输出等。该系统可以有效地代替传统消耗人力的死板工作,实现自动化数据收集以及道路交通情况的快速监测。该系统操作简单,交互性强,为城市的交通管理和交通规划提供准确实时的信息数据。

基于多元离群点检测的动态目标去除SLAM方法

考虑动态环境下的目标移动对同步定位与建图(SLAM)位姿估计精度的影响,提出一种通过稠密光流计算像素运动并经过离群点检测的动态目标SLAM算法。采用稠密光流法计算图像序列的每个像素的运动信息进行动态目标判断,利用离群点检测对动态目标进行提取,通过均值滤波对动态目标进行模糊剔除,消除动态目标对SLAM精度的影响。在TUM数据集与定制数据集上进行实验,在TUM数据集测试中,与基于特征点法的Orb-slam3标杆算法进行对比分析,在动态目标影响条件下,该算法得到的轨迹误差降低43.25%;搭建开放式四旋翼无人机测试系统,在定制数据集中,进行飞行试验,得到的估计轨迹位置误差控制在1 m内,满足使用场景要求,进一步验证了算法的有效性。

利用局部特征匹配的运动小目标光流估计

基于深度光流估计的动态背景运动小目标检测,为了保证小目标的检测性能,一般采用较少的下采样次数以维持较高的分辨率,但由此带来了较大的计算耗时。特征匹配是深度光流估计的一个核心处理环节,其耗时在光流估计整体耗时中的占比较大,且对下采样次数非常敏感。据此,提出一种基于局部特征匹配的快速光流估计算法:引入目标运动信息,缩小特征匹配的空间范围,减少待处理的数据量;设计分块局部匹配策略,引入批处理机制,避免出现逐点局部匹配策略数据处理耗时过大问题,实现算法加速。在此基础上,在光流估计获取的光流场上,采用CenterNet网络检测运动目标对应的光流异常区域。从光流估计耗时、检测精度等方面开展了实验验证,结果表明:针对运动小目标检测,分块特征匹配光流估计比全局特征匹配光流估计耗时减少约25%,目标检测性能相当。

低阻叉流板式换热器传热性能与热阻靶向调控研究

用于烟气余热回收的板式换热器存在温度分布不均的问题。为改善烟气温度分布均匀性,有效遏制换热器腐蚀,本文通过实验测试对比碳钢与铸铁材质低阻叉流板式换热器性能差异,运用数值仿真预测局部流动传热特性并开展热阻分析,采用局部热阻调控方法设计了非均匀翅片结构。实验结果表明,在450℃高温时碳钢与铸铁材质的叉流板式换热器总传热系数分别达到32.5 W/(m^(2)·K)与25.1 W/(m^(2)·K)。通过数值仿真研究发现,叉流传热方式导致烟气侧沿程截面温度分布极不均匀,在热侧出口与冷侧入口交叉区、热侧出口与冷侧出口交叉区的热阻大,极易导致局部烟气温度低于露点温度。基于热阻分析法开发非均匀翅片结构,实施局部热阻靶向调控,最终实现维持阻力几乎不变情况下,使出口截面平均温度方差由6.9℃降至1.1℃,换热器内流体温度分布均匀性得到显著提升。

目标检测下的车型对交通流速度影响研究

针对传统目标检测跟踪算法识别精度低,实时性差等缺点,提出了一种基于YOLOv5s和DeepSort算法模型的视频车辆实时车流量和速度检测方法。构建了包含25 877个目标样本的数据集,采用YOLOv5s算法模型实现视频车辆的检测,利用DeepSort算法对车辆进行跟踪计数与测速,实现了路段监控对车辆的实时检测。基于深度学习获取的速度与交通量数据,构建了不同车型对交通流速度影响模型,探究畅通状态、稳定状态、拥挤状态下车型的速度与交通量之间的关系,结果表明:算法模型对视频车辆的检测效果良好,平均准确度达到91.4%;不同状态下,车型对交通量速度的影响程度不同;畅通状态和稳定状态下,出租车的速度对交通量影响较大;拥挤状态下,私家车的车速受交通量影响较大。

塔里木盆地库车山前超深气井砂垢堵塞成因及靶向解除技术

塔里盆地库车山前超深气田是西气东输主力气源地,具有超高温、超高压、高矿化度、储层裂缝非均质性强等特征,气井生产过程中砂垢堵塞问题突出,据统计最高影响气田产能达800×104 m^(3)/d。为实现超深气井高效解堵,通过气水两相结垢热力学预测模型、裂缝性储层岩石力学实验、井筒内气液固流动模拟等研究,揭示了超深气井砂垢复合堵塞成因,并形成了靶向解堵复产关键技术。研究结果表明:①“高温流动压降结垢、裂缝面破裂出砂”是超深气井出砂结垢的内在机理;②结垢固化松散砂桥形成复合堵塞是气井堵塞减产的主要原因,其中靶向除垢是解堵复产的关键所在;③靶向除垢解堵区域为井筒变径处和井周5 m内基质—裂缝系统,气井堵塞率30%~60%为最佳解堵时机;④非酸性除垢解堵液相比常用的酸性解堵液,在同级别溶垢能力的基础上,腐蚀速率降至0.49 g/(m^(2)·h),可同时满足低腐蚀和高效除垢的技术要求。结论认为,形成的超深气井靶向除垢解堵技术在塔里木盆地库车山前超深气田规模应用159井次,有效率达93.3%,累计增产天然气75.08×10^(8)m^(3),已成为西气东输主力气井快速解堵复产的“冬保良方”,可为国内外同类气田解堵复产提供技术借鉴。

基于改进YOLOv5s的监控视频车流量检测

针对监控视频中车流量统计准确率不高,多车型车辆检测跟踪精度低、鲁棒性差等问题,提出了一种基于改进YOLOv5s的目标检测算法与DeepSort跟踪算法相结合的车流量检测方法。该方法对YOLOv5s的特征提取网络进行重构,以强化对目标重要特征的提取,提高检测器的检测精度。首先在Backbone主干网络中引入Swin Transformer模块,替换原算法中部分C3模块,增强模型全局化建模的能力,更好地捕捉上下文特征信息,扩大模型的感受野。然后对比不同的注意力机制,选择在Neck网络中接入GAM注意力,增强信息在通道与空间维度之间的跨维交互作用,减少信息损失,以强化网络的性能。最后对DeepSort跟踪算法的特征提取网络部分进行优化,并在车辆重识别数据集上重新进行训练,使其更适合对车辆的跟踪。实验结果表明,改进后的YOLOv5s与原算法相比提高了2.04%,在结合DeepSort算法后,在白天、傍晚、夜间等不同光照条件下车流量统计准确率分别达到97.5%、95.7%、85.1%。

动态场景下基于YOLOv5和几何约束的视觉SLAM算法

目的移动智能体在执行同步定位与地图构建(Simultaneous Localization and Mapping,SLAM)的复杂任务时,动态物体的干扰会导致特征点间的关联减弱,系统定位精度下降,为此提出一种面向室内动态场景下基于YOLOv5和几何约束的视觉SLAM算法。方法首先,以YOLOv5s为基础,将原有的CSPDarknet主干网络替换成轻量级的MobileNetV3网络,可以减少参数、加快运行速度,同时与ORB-SLAM2系统相结合,在提取ORB特征点的同时获取语义信息,并剔除先验的动态特征点。然后,结合光流法和对极几何约束对可能残存的动态特征点进一步剔除。最后,仅用静态特征点对相机位姿进行估计。结果在TUM数据集上的实验结果表明,与ORB-SLAM2相比,在高动态序列下的ATE和RPE都减少了90%以上,与DS-SLAM、Dyna-SLAM同类型系统相比,在保证定位精度和鲁棒性的同时,跟踪线程中处理一帧图像平均只需28.26 ms。结论该算法能够有效降低动态物体对实时SLAM过程造成的干扰,为实现更加智能化、自动化的包装流程提供了可能。