Multi-Level Parallel Network for Brain Tumor Segmentation

Accurate automatic segmentation of gliomas in various sub-regions,including peritumoral edema,necrotic core,and enhancing and non-enhancing tumor core from 3D multimodal MRI images,is challenging because of its highly heterogeneous appearance and shape.Deep convolution neural networks(CNNs)have recently improved glioma segmentation performance.However,extensive down-sampling such as pooling or stridden convolution in CNNs significantly decreases the initial image resolution,resulting in the loss of accurate spatial and object parts information,especially information on the small sub-region tumors,affecting segmentation performance.Hence,this paper proposes a novel multi-level parallel network comprising three different level parallel subnetworks to fully use low-level,mid-level,and high-level information and improve the performance of brain tumor segmentation.We also introduce the Combo loss function to address input class imbalance and false positives and negatives imbalance in deep learning.The proposed method is trained and validated on the BraTS 2020 training and validation dataset.On the validation dataset,ourmethod achieved a mean Dice score of 0.907,0.830,and 0.787 for the whole tumor,tumor core,and enhancing tumor core,respectively.Compared with state-of-the-art methods,the multi-level parallel network has achieved competitive results on the validation dataset.

Separating spins by dwell time of electrons across parallel double δ-magnetic-barrier nanostructure applied by bias

The dwell time and spin polarization(SP)of electrons tunneling through a parallel doubleδ-magnetic-barrier nanostructure in the presence of a bias voltage is studied theoretically in this work.This nanostructure can be constructed by patterning two asymmetric ferromagnetic stripes on the top and bottom of InAs/AlxIn1-xAs heterostructure,respectively.An evident SP effect remains after a bias voltage is applied to the nanostructure.Moreover,both magnitude and sign of spin-polarized dwell time can be manipulated by properly changing the bias voltage,which may result in an electrically-tunable temporal spin splitter for spintronics device applications.

Constitutive equations of 1060 pure aluminum based on modified double multiple nonlinear regression model

In order to study the work-ability and establish the optimum hot formation processing parameters for industrial 1060 pure aluminum, the compressive deformation behavior of pure aluminum was investigated at temperatures of 523?823 K and strain rates of 0.005?10 s?1 on a Gleeble?1500 thermo-simulation machine. The influence rule of processing parameters (strain, strain rate and temperature) on flow stress of pure aluminum was investigated. Nine analysis factors consisting of material parameters and according weights were optimized. Then, the constitutive equations of multilevel series rules, multilevel parallel rules and multilevel series &parallel rules were established. The correlation coefficients (R) are 0.992, 0.988 and 0.990, respectively, and the average absolute relative errors (AAREs) are 6.77%, 8.70% and 7.63%, respectively, which proves that the constitutive equations of multilevel series rules can predict the flow stress of pure aluminum with good correlation and precision.

AN IMPROVED RECURSIVE DOUBLING ALGORITHM FOR THE PARALLEL SOLUTION OF LINEAR RECURRENCE R

An improved recursive doubling algorithm for solving linear recurrence R <n,1>is given,whose parallel time complexity is (τ++τ.) logn when n processors are available,achieving the lower bound in array processor type computation.

Crop Leaf Disease Recognition Network Based on Brain Parallel Interaction Mechanism

In the actual complex environment,the recognition accuracy of crop leaf disease is often not high.Inspired by the brain parallel interaction mechanism,a two-stream parallel interactive convolutional neural network(TSPI-CNN)is proposed to improve the recognition accuracy.TSPI-CNN includes a two-stream parallel network(TSP-Net)and a parallel interactive network(PI-Net).TSP-Net simulates the ventral and dorsal stream.PI-Net simulates the interaction between two pathways in the process of human brain visual information transmission.A large number of experiments shows that the proposed TSPI-CNN performs well on MK-D2,PlantVillage,Apple-3 leaf,and Cassava leaf datasets.Furthermore,the effect of numbers of interactions on the recognition performance of TSPI-CNN is discussed.The experimental results show that as the number of interactions increases,the recognition accuracy of the network also increases.Finally,the network is visualized to show the working mechanism of the network and provide enlightenment for future research.

电动拖拉机双电源并联控制研究

电动拖拉机具有结构简单和节能减排等优点,但现有电动拖拉机作业时采用单一动力电池能源,存在续航时间短的问题。为了提高电动拖拉机长续航供电能力,提出了一种基于下垂控制的直流双电源并联均流联合供电方案,利用MatLab/Simulink搭建了系统模型。仿真试验表明:单电源可以实现升压稳压控制;基于下垂控制的双电源并联均流能够实现双电源的电流均流;当切换不同功率负载时,系统电压随功率增加按比例下调,验证了该方案的可行性。

Brain-lung crosstalk: Implications for neurocritical care patients

Major pulmonary disorders may occur after brain injuries as ventilator-associated pneumonia, acute respiratory distress syndrome or neurogenic pulmonary edema. They are key points for the management of brain-injured patients because respiratory failure and mechanical ventilation seem to be a risk factor for increased mortality, poor neurological outcome and longer intensive care unit or hospital length of stay. Brain and lung strongly interact via complex pathways from the brain to the lung but also from the lung to the brain. Several hypotheses have been proposed with a particular interest for the recently described "double hit" model. Ventilator setting in brain-injured patients with lung injuries has been poorly studied and intensivists are often fearful to use some parts of protective ventilation in patients with brain injury. This review aims to describe the epidemiology and pathophysiology of lung injuries in brain-injured patients, but also the impact of different modalities of mechanical ventilation on the brain in the context of acute brain injury.

Study on Interaction Between Two Parallel Plates with Iteration Method in Functional Theory

By introducing the functional theory into the calculation of electric double layer （EDL） interaction, the interaction energies of two parallel plates were calculated respectively at low, moderate, and high potentials. Compared with the results of two existing methods, Debye-Hückel and Langmuir methods, which are applicable just to the critical potentials and perform poorly in the intermediate potential, the functional approach not only has much simpler expression of the EDL interaction energy, but also performs well in the entire range of potentials.

Parallel transjugular intrahepatic portosystemic shunt with Viatorr^(®)? stents for primary TIPS insufficiency:Case series and review of literature

BACKGROUND Transjugular intrahepatic portosystemic shunts(TIPS) can alleviate complications of portal hypertension such as ascites and variceal bleeding by decreasing the portosystemic gradient.In limited clinical situations,parallel TIPS may be only solution to alleviate either variceal bleeding or ascites secondary to portal hypertension when the primary TIPS fails to do so.Data specifically addressing the use of this partially polytetrafluoroethylene covered nitinol stent(Viatorr~?) is largely lacking despite Viatorr~? being the current gold standard for modern TIPS placement.CASE SUMMARY All three patients had portal hypertension and already had a primary Viatorr~?TIPS placed previously.All patients have undergone failed endoscopy to manage acute variceal bleeding before referral for a parallel stent(PS).PS were placed in patients presenting with recurrent variceal bleeding despite existence of a widely patent primary TIPS.Primary stent patency was verified with either Doppler ultrasound or intra-procedural TIPS stent venography.Doppler ultrasound follow-up imaging demonstrated complete patency of both primary and parallel TIPS.All three patients did well on clinical follow-up of up to six months and no major complications were recorded.A review of existing literature on the role of PS in the management of portal hypertension complications is discussed.There are three case reports of use of primary and PS Viatorr~? stents placement,only one of which is in a patient with gastrointestinal variceal bleeding despite a patent primary Viatorr~? TIPS.CONCLUSION Viatorr~? PS placement in the management of variceal hemorrhage is feasible with promising short term patency and clinical follow-up data.

Oligodendrocyte transcription factor 1 mRNA and protein expression in organotypic rat brain slices

Numerous studies have confirmed that oligodendrocyte transcription factor 1 （Olig-1） is vital for myelin repair. However, the effects of hypoxia and ischemia on Olig-1 expression remain unknown. In this study, Olig-1 mRNA and protein expressions were analyzed by in situ hybridization and immunohistochemistry, to determine the expression profile of Olig-1 in rat brain slices exposed to hypoxia and ischemia. Brains were obtained from 2-day-old Sprague-Dawley rats, and sections were randomly assigned to control and hypoxia/ischemia groups. Hematoxylin-eosin staining revealed karyorrhexis and karyopyknosis in cells from the hypoxia/ischemia group. Under electron microscopy, mitochondria swelling and neuropil edema were observed in the hypoxiaJischemia group. Olig-1 mRNA and protein expressions were increased at 1 day after hypoxia and ischemia treatment. These results suggest that in situ hybridization and immunohistochemistry could be used simultaneously to detect mRNA and protein expression in brain slices.

基于修正Loganathan公式的非水平布置双线平行盾构隧道施工引起土体位移计算方法

[目的]为研究双线平行盾构隧道非水平布置方式下,由施工引起的周围土体位移规律,提出一种基于修正Loganathan公式的土体位移计算方法。[方法]介绍了Loganathan公式及相关假设;考虑盾构隧道开挖扰动引起的地层损失、土体卸荷回弹和土体损失率沿掘进路径变化的综合影响,修正Loganathan公式并建立单线盾构隧道周围土体位移解;建立双线平行盾构隧道非水平布置方式下,由施工引起的土体位移计算方法;通过实际工程的现场监测和数值模拟结果,验证所提计算方法的工程适用性。[结果及结论]所提计算方法能够考虑隧道轴心连线与水平面夹角、双线隧道半径、隧道轴心间距、双线隧道埋深等双线隧道布置因素,以及隧道盾构施工扰动造成的地层损失、土体卸荷回弹和土体损失率沿掘进路径变化等施工因素对土体位移的影响。地面沉降及土体水平位移的理论计算结果同现场监测结果和数值模拟结果之间的平均误差分别为5.6%、0.6%和5.5%、5.3%,均满足工程经验规定的20%的精度要求,说明所提计算方法能够有效解决双线平行盾构隧道非水平布置方式下施工引起的土体位移计算问题,具有良好的工程适用性。

间隔织物双剑杆织机平行打纬机构箱体的振动分析

针对双剑杆织机共轭凸轮与四连杆组合的平行打纬机构箱体随着织机转速的提高产生强烈振动,影响打纬精度和可靠性的问题,采用理论分析与虚拟仿真结合的方法对打纬机构及箱体进行动应力和振动特性研究。建立了平行打纬机构的动态静力分析方程,运用ADAMS软件对机构进行多体动力学仿真,求解箱体所受的支反力;构建箱体—弹簧阻尼—柔性基础的系统模型,分析箱体在竖直方向的受迫振动,并在仿真过程中探索减小箱体振动的方法。研究结果表明:摆臂轴孔处箱体所受支反力峰值最大,打纬推程阶段箱体的受力最为集中;当凸轮轴转速为260 r/min时齿轮啮合频率与箱体一阶固有频率相等,会产生共振,应避免使用这一转速工作;箱体在竖直方向上产生周期性振动,增加螺栓个数和附加动力减震器有助于改善箱体的振动特性,振幅分别减少38%和23%。

双并列转子永磁电机非对称负载运行特性

双并列转子电机在驱动两侧非对称负载时,轻载侧电机的功角较低,产生了电机材料浪费,效率低等问题。为提升电机整体输出功率,基于双并列转子电机基本理论采用解析法求得电机驱动转矩平均值的表达式,进而提出轻载侧绕组提前的结构设计。而后以一台12极72槽双并列转子电机为例,建立其磁网络模型,通过麦克斯韦应力张量法得出驱动转矩的解析计算式,分析转子偏差角对电机基本转矩脉动的影响,得出最佳绕组提前槽数。最后,针对电机转矩脉动较大的问题,使用响应曲面法,以基本转矩脉动为目标函数,以永磁体偏心距、永磁体极弧系数、并接区高度作为自变量对电机进行优化,有效降低电机转矩脉动,验证了绕组前置的结构改进对提升电机非对称状态下的输出转矩具有显著效果。

“双线并行、五措并举”的高职学生党员培养路径创新研究

学生党员培养是高校党建工作的重要内容之一,党员培养质量关系着党和国家事业的发展。分析了高职学生党员培养的必要性及存在问题,提出了打造高职院校党务工作专业化队伍、创新“线上+线下”并行和“必修+选修”并重的党员培养方式、创新“精选+情感培养”的入党动机教育方法、建立“1+1+1”三段式党员长效培养机制和构建“4+15”党员考核评价体系“五措并举”的学生党员培养创新路径,旨在提升新媒体时代高职学生党员培养质量。

含平行双裂隙白砂岩力学行为数值分析

目的为探究平行双裂隙对白砂岩力学特性、裂纹扩展和能量演化的影响,方法利用颗粒流软件PFC2D获取白砂岩细观力学参数,通过改变双裂隙倾角和双裂隙间距2个关键影响因素,进行多次单轴压缩试验并对模拟结果进行分析。结果结果表明:随着裂隙倾角增大,岩石的峰值强度、弹性模量变大;随着平行双裂隙间距增大,裂隙倾角为30°时,岩石的峰值强度和弹性模量大幅降低,裂隙倾角为60°时,裂隙间距对岩石的峰值强度和弹性模量无显著影响,即裂隙间距转变为影响力学特性的次要因素;裂隙倾角对岩石的微裂纹发育过程有着重要影响,在裂纹扩展初期以拉伸裂纹为主,最终破坏形式多为剪切破坏;裂隙倾角为45°时,裂纹发育至贯通最为彻底;随着裂隙倾角增大,耗散能开始出现应变节点逐渐后移现象,岩石的弹性储能极限随之增强,裂隙倾角为0°~15°时,储能极限会发生一次小幅度反弹。结论双裂隙倾角和间距对白砂岩力学特性、裂纹扩展和能量演化的影响至关重要。

大思政背景下高职英语“323”教学实施路径探究--以黄冈职业技术学院为例

在大思政背景下,从高职英语融入思政元素的必要性出发,探究高职英语实施课程思政的基本思路,“323”教学路径的构建与实施以及实施中应注意的问题。研究认为教学实践应当注重线上线下相结合,实施课前、课中、课后“三阶递进”的教学过程,坚持技能培养和文化培育“双元共育”的教学理念,结果表明英语“323”教学实施,可以实现知识传授、能力提升、价值塑造“三位一体”的育人目标。

并联双线圈式直流接触器电磁机构合闸动作特性

直流接触器是新能源系统以及电动汽车中配置最为广泛的开关电器之一。而直流接触器的动态特性是衡量直流接触器性能的重要指标之一。文中以并联双线圈式直流接触器为研究对象,建立了直流接触器电磁机构的动力学模型,利用基于Adams与Maxwell软件的联合仿真研究方法对直流接触器的电磁机构进行合闸过程的仿真分析,研究结果表明,机构合闸动作的仿真合闸时间与试验合闸时间相吻合,验证了该仿真方法的正确性。同时研究了弹簧参数和线圈参数等因素对机构合闸运动特性的影响,发现在一定范围内弹簧预压力变化对合闸时间影响不大,线圈安匝数增大会导致合闸时间变小,线圈内阻增大会导致合闸时间变大且动触头弹跳更剧烈。文中的仿真方法与结果能为直流接触器电磁机构的改进设计与优化提供一定参考。

基于正序瞬时功率算法的宽频振荡检测技术

现代电力系统表现出含高比例可再生能源和高比例电力电子设备的“双高”特征,电力系统中不同频率的谐波、间谐波与工频量相互作用,将可能导致宽频振荡,威胁电力系统安全稳定运行。针对无法在三相不平衡状态下实现宽频振荡准确检测的问题,提出了基于FPGA(现场可编程门阵列)和正序瞬时功率算法的宽频振荡检测技术。利用三相正序瞬时功率能滤除三相不平衡分量的原理,确保宽频振荡的检测结果不受三相不平衡的影响。利用FPGA并行计算的特性,大幅提升了宽频振荡检测算法的性能。测试结果表明,该技术能够在发生宽频振荡时准确检测出振荡分量,解决了现有技术存在误判和并行计算能力不足的问题。

多通道双晶单色器平行度测量与运动轨迹规划

针对双转轮多通道双晶单色器的平行度误差补偿问题,提出一种基于光电自准直仪的多通道双晶单色器准静态双晶衍射面平行度测量方法以及一种S形曲线轨迹规划方法。分析多通道单色器的结构及运动特点,基于光电自准直仪提出多通道双晶单色器平行度测量系统的总体框架及测量具体流程。结合多通道双晶单色器运动特点,提出一种S形曲线轨迹规划方法,并基于平行度测量结果对单色器运动轨迹进行优化设计。最后,在搭建的实验平台上开展准静态平行度测量实验及运动轨迹跟踪实验。结果表明:所搭建的平行度测量系统的平行度分辨率达0.5″,相邻两组晶体角度跃迁差值在百角秒量级;所提S形曲线轨迹规划算法将轨迹跟踪误差抑制在6.1″,相比传统5阶多项式及未规划轨迹,跟踪误差分别降低58.7%和63.9%。实验结果验证了所提方法有效性,对改进双转轮多通道双晶单色器性能具有良好的实际应用价值。

某双管同沟敷设管线阴极保护系统干扰防护数值模拟研究

为明确同沟敷设管道阴极保护系统相互干扰规律及干扰防护措施,以新疆油田某双管同沟敷设管道(D219和D457)为模型,设置D219管道的涂层破损率为0.1%,D457管道的涂层破损率为0.1%、0.5%、1.0%,采用数值模拟方法对不同阴极保护设计及阴极保护干扰防护措施的有效性及适用性进行评估。结果表明:采用浅埋阳极单独阴极保护的同沟敷设管道存在阴极保护系统相互干扰,随着干扰管道D457防腐层破损率的增加,其对并行管道D219的干扰程度增强,施加均压线措施可有效降低干扰;采用浅埋阳极联合阴极保护+均压线措施可消除同沟敷设管道阴极保护系统的相互干扰,当双管同沟管道防腐层破损率相差较大(D2190.1%,D4571.0%)时,改善效果较为显著;对于采用深井阳极联合阴极保护的同沟敷设管道,当D457防腐层破损率较大(1.0%)、土壤电阻率较高(50Ω·m)时,其阴极保护效果较差,采用均压线+牺牲阳极措施对阴极保护效果的改善作用不明显,而增大深井阳极输出电流联合均压线措施可显著改善同沟敷设管道的阴极保护效果。