Studied on a novel human keratinocyte membrane delivery system in vitro

The culture of keratinocytes on flexible membranes has been proposed as a means to simplify, accelerate and improve the efficiency with which proliferating cells are delivered to full thickness or non-healing skin defects. The purpose of this article was to study the ability of chitosan-gelatin manbranes to facilitate the growth of human keratinocytes. The membranes with different chitosan contents were studied. The surface properties of chitosan-gelatin membranes were investigate by SEM, and water contact angle test. The mechanical property of the membranes was tested. Data implied that gelatin could make the membranes more flexible and hydrophilic than chitosan membranes, which may regulate the seeded cells behavior. Loading human keratinocytes on chitosan-gelatin membranes, cells attachment, spread, and growth were investigated by light microscopy, SEM, and MTT test. The results suggested that the adhesion and proliferation of keratinocytes seeded on chitosan-gelatin membranes were same as on tissue culture plate, in which gelatin could modify the interaction between keratinocytes and chitosan membranes. Therefore, chitosan-gelatin membrane is a good candidate for keratinocytes delivery system.     

中厚板矫直过程中中性层偏移动态研究

研究中性层偏移对矫直力的影响,以提高矫直力精度。通过对矫直件三维弹塑性变形进行分析,提出中性层偏移理论,利用数值模拟和实验讨论中性层偏移的动态变化规律,说明中性层偏移是影响矫直力精度的重要因素之一,并验证了理论推导公式与数值计算结果之间的误差,为建立更为准确的矫直力模型提供理论基础和数据。     

Large-scale fabrication of bioinspired fibers for directional water collection

Spider-silk inspired functional fibers with periodic spindle-knots and the ability to collect water in a directional manner are fabricated on a large scale using a fluid coating method. The fabrication process is investigated in detail, considering factors like the fiber-drawing velocity, solution viscosity, and surface tension. These bioinspired fibers are inexpensive and durable, which makes it possible to collect water from fog in a similar manner to a spider's web.     

Piezoelectric and dielectric properties of PZN-BT-PZT solid solutions

Pb(Zn_1/3Nb_2/3)O₃ ceramics with the perovskite structure can be stabilized by substituting 6–7 mol % BaTiO₃ (BT). Piezoelectric and dielectric properties of the pseudo-binary system (1–x)(0.94PZN-0.06BT) -xPb(Zr_(1–y)Ti_y)O₃ were studied, and the effects of Zr/Ti ratios and thermal annealing process on the piezoelectric and dielectric properties were also discussed. The results show that the piezoelectric properties of this ceramic system are very good when x is about 0.50 and y is about 0.47 with K_p = 70%, d₃₃=560 pC/N, _m #x2248;23,000. These ceramics are favorable to piezoelectric actuators.     

改进YOLOv8的水面小目标检测算法

针对水面目标检测中的噪声干扰和小目标的漏检问题,提出一种改进YOLOv8的水面小目标检测算法YOLOv8-WSSOD (YOLOv8-water surface small object detection).首先,为降低水面复杂环境在主干网络下采样过程中产生的噪声干扰,提出基于BiFormer双层路由注意力机制构建的C2fBF (C2f-BiFormer)模块,在特征提取过程中保留细粒度的上下文特征信息;其次,针对水面小目标的漏检问题,新增一个更小的检测头,提升网络对小目标的感知力,并在Neck端引入GSConv和Slim-neck,减轻模型复杂度并保持精度;最后,使用MPDIoU损失函数解决CIoU损失函数的局限性,以提高模型检测准确率.实验结果表明,相较于原始YOLOv8算法,该算法在水面小目标上平均准确率mAP@0.5提升了4.6%, mAP@0.5:0.95提升了2.2%,并且改进后的算法检测速度达到86f/s,能有效实现对水面小目标快速、准确的检测.     

融合注意力机制的轻量级摔倒检测

摔倒检测大都依靠传感器设备,此类方法受设备自身和环境因素影响较大,常常无法发挥该有的作用,同时,基于视觉的方法往往实时性较差,鲁棒性不强。针对上述问题,本文提出了一种鲁棒性强、能有效部署在嵌入式设备上的轻量化摔倒检测算法。以YOLOv5为基准模型,首先,融合轻量级注意力机制模块,使网络更关注要识别的目标区域,增强网络的识别精度。其次,使用模型压缩方法对模型进行剪枝,减小模型体积和计算量,使模型轻量化,以提高推理速度和便于部署在嵌入式设备中。最后,对剪枝后的模型进行知识蒸馏,在不提升模型复杂度的前提下提升模型的检测精度。实验结果表明：本文模型相较于基准模型,mAP增加了1.7%,召回率提高了1.2%,模型体积减小了79.1%,浮点运算量降低了70.9%。将本文模型部署在嵌入式设备Jetson Nano上,检测速率达到13.2 frame/s,基本满足实时性摔倒检测的要求。     

平行导线对的辐射发射估计

载有高频电流的导线对会产生电磁骚扰,干扰周围的电子设备.评估导线对的电磁发射具有重要的工程应用价值.文中提出了远离任何其它障碍物、置于自由空间的孤立导线对的一阶发射模型,用于估计平行导线对的辐射发射.依据FCC的B级EMC标准,实例预测了电流大小和类型对辐射发射的潜在影响,结果表明:与差模电流相比,共模电流能够产生显著的辐射发射.