基于笔划组合的手写数字切分

主曲线是一种新的基于非线性变换的特征抽取方法,它是一种通过数据分布“中间”并满足“自相合”的光滑曲线来进行特征提取的方法。为了提高手写数字串切分的正确率,提出了一种基于笔划组合的手写数字串切分方法。该方法首先使用主曲线完成字符模板的笔划抽取,然后以字符识别器提供的置信度为依据来组合笔划,以实现手写数字串的切分过程。另外,在字符识别器设计方面,则是使用基于数字轮廓分段特征与规范化模板特征这两个单特征分类器组合。实验表明,分别基于这两个特征的分类器具有较强的互补性。由于字符识别器的置信度难以真实反映识别结果,为此需使用类条件置信变换法,通过估计分类器的后验概率来对识别器的置信度进行修正。实验结果表明,该方法对于手写数字的分割是有效的。     

郑州煤业集团矿山线雷击断线事故的分析与对策

雷击断线是严重的煤矿供电安全事故,直接威胁着煤矿的安全生产。文章介绍了雷击断线事故的原因;通过建立雷击导线的电流源电路模型,分析了雷电流及其引发的相间短路电流的热效应和雷击断线的机理;给出了接地系统不完善是造成雷击断线事故的间接原因、雷击引发的相间短路电流是造成断线的直接原因的结论;最后,结合供电线路的实际提出了防止雷击事故的技术对策。     

一种基于多分辨率和统计的笔刷绘制方法

采用高斯图像金字塔生成多幅参考图像,使用不同大小的笔刷进行多层绘制,模拟画家由粗到细的创作过程,设计一种新的笔刷绘制方法。在每层绘制时,使用统计方法确定笔刷的颜色,运用像素8-邻域的概念控制笔刷的走势。实验结果表明,通过多个参数的不同设置可以将一幅照片渲染成具有一定风格的艺术图像。     

基于统计分析的虚拟毛笔模型及其应用

为了以较低运算开销和设备成本实现书法的真实显示,利用F-Tablet硬件系统,通过分析力信息和笔画宽度之间的统计关系建立虚拟毛笔模型。该模型可以节省大量计算时间,达到实时交互目的。与一阶线性模型、ARMA模型和模糊推理模型进行比较,结果表明该模型的书写效果较好。     

微波前向散射法研究出血性脑中风

用微波前向散射法探究出血性脑中风的出血量。该法利用脑出血状态及正常大脑状态下收发天线之间传输系数的幅度S21 和相位渍S21 差值变化、以及大脑的电场分布数值的变化来检测脑中风出血位置。文中用三维人体组织电磁仿真软件Sim4Life 提供精细的大脑模型,在大脑中植入直径为10 mm、20 mm、30 mm 的血球模型,并将三个血球模型置于大脑同一位置,然后搭建模拟脑出血的实验平台进行实测,由不同规格的试管模拟不同规格的出血量,最终验证了仿真结果与实验结果一致。实验证明,大脑出血量越大对收发天线间传输系数以及电场强度的影响越大。     

Ferrimagnetic Nanochains‐Based Mesenchymal Stem Cell Engineering for Highly Efficient Post‐Stroke Recovery

Unsatisfactory post‐stroke recovery has long been a negative factor in the prognosis of ischemic stroke due to the lack of pharmacological treatments. Mesenchymal stem cells (MSCs)‐based therapy has recently emerged as a promising strategy redefining stroke treatment; however, its effectiveness has been largely restricted by insufficient therapeutic gene expression and inadequate cell numbers in the ischemic cerebrum. Herein, a non‐viral and magnetic field‐independent gene transfection approach is reported, using magnetosome‐like ferrimagnetic iron oxide nanochains (MFIONs), to genetically engineer MSCs for highly efficient post‐stroke recovery. The 1D MFIONs show efficient cellular uptake by MSCs, which results in highly efficient genetic engineering of MSCs to overexpress brain‐derived neurotrophic factor for treating ischemic cerebrum. Moreover, the internalized MFIONs promote the homing of MSCs to the ischemic cerebrum by upregulating CXCR4. Consequently, a pronounced recovery from ischemic stroke is achieved using MFION‐engineered MSCs in a mouse model.     

Air-writing recognition using reverse time ordered stroke context

Air-writing is a new human and smart device communication approach, permits users to write inputs in a natural and relentless way. This touch-less way can prevent users from virus infection such as COVID-19. Compared with other methods, air writing is more challenging due to its unique characteristics such as redundant lifting strokes, multiplicity (different writing styles from various users), and confusion (different character types written in air are similar). Without the need of any starting trigger, a novel reverse time-ordered algorithm is proposed in this paper to efficiently filter out unnecessary lifting strokes, and thus simplifies the matching procedure. As to the second and third issues, a tiered arrangement structure is proposed by sampling the air-writing results with various sampling rates to solve the multiplicity and confusion problems. Analyzed with other recently proposed air writing algorithms, the proposed approach reaches satisfactory recognition accuracy (above 94%) without any starting triggers.     

炸药性能与岩石匹配的试验研究

为了探究炸药和岩石的匹配关系,以寻求最优的匹配效果,最终将大块率控制在合理范围以内,创造良好的经济效益和社会效益。在江西德兴铜矿爆破施工中,采用岩块投影的最大面积和周长作为衡量矿岩块度的标准几何特征参量,并运用AutoCAD二次开发VB编程进行数据处理,采用回归分析法探讨炸药和岩石的匹配关系,最后得到最优匹配区的匹配系数为2.50².58。     

雷管爆炸产物与破片飞散过程研究

运用高速摄像技术探究钢壳平底、凹底雷管爆炸产物与破片的飞散规律,同时对不同管壳材质的凹底雷管反转弹丸的速度变化规律进行探究。研究表明:钢壳凹底雷管爆炸产物径向运动速度大于平底雷管;钢壳凹底雷管爆炸后,其聚能穴翻转变形产生反转弹丸,反转弹丸的头部速度在尾部拉应力的作用下逐渐下降;雷管爆炸95μs后,反转弹丸头部和尾部断裂,拉应力作用消失,头部速度骤然升高达到最大值;在距离雷管底部270mm内,钢壳凹底雷管反转弹丸的头部速度为1 440m/s,铜壳为3 204m/s,铝壳为6 350m/s。     

Microthrombus‐Targeting Micelles for Neurovascular Remodeling and Enhanced Microcirculatory Perfusion in Acute Ischemic Stroke

Reperfusion injury exists as the major obstacle to full recovery of neuron functions after ischemic stroke onset and clinical thrombolytic therapies. Complex cellular cascades including oxidative stress, neuroinflammation, and brain vascular impairment occur within neurovascular units, leading to microthrombus formation and ultimate neuron death. In this work, a multitarget micelle system is developed to simultaneously modulate various cell types involved in these events. Briefly, rapamycin is encapsulated in self‐assembled micelles that are consisted of reactive oxygen species (ROS)‐responsive and fibrin‐binding polymers to achieve micelle retention and controlled drug release within the ischemic lesion. Neuron survival is reinforced by the combination of micelle facilitated ROS elimination and antistress signaling pathway interference under ischemia conditions. In vivo results demonstrate an overall remodeling of neurovascular unit through micelle polarized M2 microglia repair and blood–brain barrier preservation, leading to enhanced neuroprotection and blood perfusion. This strategy gives a proof of concept that neurovascular units can serve as an integrated target for ischemic stroke treatment with nanomedicines.