一种基于深度森林的恶意代码分类方法

针对当前恶意代码静态分析方法精度不足的问题，将恶意代码映射为无压缩的灰度图像，然后根据图像变换方法将图像变换为恒定大小的图像，使用方向梯度直方图提取图像的特征，最后提出一种基于深度森林的恶意代码分类方法.实验中选择不同家族的多个恶意代码样本进行分类，验证了该方法的有效性，并且实验结果优于近期提出的SPAM-GIST方法.     

Microwave irradiated Carrageenan-Guar gum micro-porous IPN: a novel material for isotropic tissue scaffolding

In this study, a novel micro porous honeycomb structured Crg-GG-IPN material was incepted to be applicable as scaffold and accomplished. The hydrophilicity was confirmed by FT-IR and OCA. Amorphous nature and micro-rough surface were confirmed by XRD and AFM. Void fraction was 0.61?±?0.04. Void space, hemocompatibility and platelet adhesion were captured by SEM. Degradability of the material was confirmed by in-vitro degradation study. Incision method using mice model was a clear evidence for cell attachment and non-toxicity and was confirmed from hematology and histopathology. Thus, it appears that Crg-GG scaffolds can be useful as wound healing material for clinical applications.     

煤颗粒与气泡黏附行为的试验研究

浮选微观模型认为,颗粒与气泡的黏附是实现浮选的关键步骤,对颗粒与气泡黏附规律的直接研究非常重要。采用自行设计搭建的颗粒与气泡碰撞、黏附行为测量装置,以内蒙古公乌素原煤为试验对象,直接观测了不同密度级的0.1~0.15 mm粒级煤样的黏附行为,并采用自行开发的多目标追踪软件进行分析。结果表明:煤颗粒在与气泡碰撞前会发生绕流,速度大小和方向均会改变,当煤颗粒与气泡碰撞时,煤颗粒的速度降为最低。煤颗粒在气泡表面的滑动速度先是逐渐增大,在气泡"赤道"位置处达到最大值,越过"赤道"后,煤颗粒的滑动速度逐渐减小,并最终黏附在气泡底部。煤颗粒与气泡的黏附效率随碰撞角的增大而降低,在碰撞角相同时,随煤样密度级的增大,黏附效率降低,临界黏附角减小。随煤颗粒沉降末速的增大,煤颗粒与气泡的黏附效率降低,临界黏附角减小。     

稀土元素Ce对取向硅钢热轧钢带组织和织构的影响

对2250 mm热轧生产线生产的取向硅钢热轧钢带的合金体系进行了设计,制定了合理的加热制度和热轧轧制工艺。对添加稀土元素Ce的取向硅钢铸坯和热轧钢带进行了分析,探究了稀土元素Ce对取向硅钢低倍组织、热轧织构及成品磁性能的影响。结果表明,稀土元素Ce能够细化取向硅钢连铸坯低倍组织和热轧显微组织,提高取向硅钢成品磁性能。     

Data-driven parameterization of polymer electrolyte membrane fuel cell models via simultaneous local linear structured state space identification

In order to mitigate the degradation and prolong the lifetime of polymer electrolyte membrane fuel cells, advanced, model-based control strategies are becoming indispensable. Thereby, the availability of accurate yet computationally efficient fuel cell models is of crucial importance. Associated with this is the need to efficiently parameterize a given model to a concise and cost-effective experimental data set. A challenging task due to the large number of unknown parameters and the resulting complex optimization problem. In this work, a parameterization scheme based on the simultaneous estimation of multiple structured state space models, obtained by analytic linearization of a candidate fuel cell stack model, is proposed. These local linear models have the advantage of high computational efficiency, regaining the desired flexibility required for the typically iterative task of model parameterization. Due to the analytic derivation of the local linear models, the relation to the original parameters of the non-linear model is retained. Furthermore, the local linear models enable a straight-forward parameter significance and identifiability analysis with respect to experimental data. The proposed method is demonstrated using experimental data from a 30 kW commercial polymer electrolyte membrane fuel cell stack.     

开关磁阻直线电机的设计及其推力优化

设计了一种开关磁阻直线电机,使用JMAG软件对其进行了仿真和优化。进行了推力公式的推导,研究了导通顺序和初始位置对电机推力的影响,并分析了三种典型情况的磁力线分布。对电机的定子和动子的齿部和轭部高度、宽度及铁耗进行仿真优化,得出了最优参数。将有取向硅钢应用于该电机,研究了推力与轧制角的关系,并与使用普通硅钢的开关磁阻直线电机进行了对比,推力有一定提升。提出在动子齿部开切向槽的方案,结果表明,开切向槽对推力的影响较小,并能显著减小推力波动。     

复杂炼油塔模拟的改进联立方程内外层算法

在内外层算法的基础上，采用联立方程思想将主塔、侧线汽提塔视为一个整体进行建模，并针对复杂炼油塔的特点对算法提出了改进。首先，由于传统内外层法简化的K值模型对组成的变化不敏感，在处理带有石油的体系时，容易出现迭代次数较多，甚至部分塔板温度更新异常的问题，因此采用了汽相分数加和式推导了简化的K值模型加权因子。其次，借鉴流量加和法思想，规定侧线汽提塔的塔底产品流量作为设计变量，增强了算法收敛的稳定性。为验证改进后算法的有效性，采用不同的算法对实际的常压塔进行了模拟，结果显示改进后的算法适合应用于复杂炼油塔的模拟计算。     

基于极坐标特征矩阵的多类对象排列结构描述方法

本文提出一种基于极坐标特征矩阵的多类对象排列结构检测方法。极坐标特征矩阵由极径矩阵和极角矩阵构成,它描述了多类对象排列结构中所包含的距离信息和方向信息。该方法在汽车保险盒检测应用上取得了显著的效果,针对于汽车保险盒检测,首先使用CCD工业相机采集保险盒图像,通过方向梯度直方图特征对汽车保险片的标识码进行表征,并结合支持向量机实现对图像中的保险片的定位与识别。然后依据定位和识别结果计算极坐标特征矩阵对汽车保险盒内汽车保险片的排列结构进行描述。最后以极坐标特征矩阵相似度为判断依据实现对汽车保险盒的检测。实验证明,依据极坐标特征矩阵相似度对汽车保险盒的检测准确率达97.6%。     

Modelling the combined effect of surface roughness and topography on bacterial attachment

Bacterial attachment is a complex process affected by flow conditions,imparted stresses,and the sur-face properties and structure of both the supporting material and the cell.Experiments on the initial attachment of cells of the bacterium Streptococcus gordonii (S.gordonii),an important early coloniser of dental plaque,to samples of stainless steel (SS) have been reported in this work.The primary aim motivating this study was to establish what affect,if any,the surface roughness and topology of sam-ples of SS would have on the initial attachment of cells of the bacterium S.gordonii.This material and bacterium were chosen by virtue of their relevance to dental implants and dental implant infections.Prior to bacterial attachment,surfaces become conditioned by the interfacing environment (salivary pellicle from the oral cavity for instance).For this reason,cell attachment to samples of SS pre-coated with saliva was also studied.By implementing the Extended Derjaguin Landau Verwey and Overbeek(XDLVO) theory coupled with convection-diffusion-reaction equations and the surface roughness infor-mation,a computational model was developed to help better understand the physics of cell adhesion.Surface roughness was modelled by reconstructing the surface topography using statistical parame-ters derived from atomic force microscopy (AFM) measurements.Using this computational model,the effects of roughness and surface patterns on bacterial attachment were examined quantitatively in both static and flowing fluid environments.The results have shown that rougher surfaces (within the sub-microscale) generally increase bacterial attachment in static fluid conditions which quantitatively agrees with experimental measurements.Under flow conditions,computational fluid dynamics (CFD) simula-tions predicted reduced convection-diffusion inside the channel which would act to decrease bacterial attachment.When combined with surface roughness effects,the computational model also predicted that the surface topographies discussed within this work produced a slight decrease in overall bacterial attachment.This would suggest that the attachment-preventing effects of surface patterns dominate over the adhesion-favourable sub-microscale surface roughness;hence,producing a net reduction in adhered cells.This qualitatively agreed with experimental observations reported here and quantitatively matched experimental observations for low flow rates within measurement error.     

宝钢低铁损取向硅钢在变压器新能效标准下的应用

随着变压器新能效标准GB 20052-2020的正式实施，变压器各能效等级普遍提升，也推动取向硅钢产品等级的提高。本文结合新能效标准，针对宝钢低铁损取向硅钢产品应用实绩，给出选材建议，并针对产品使用过程中存在的问题进行剖析，以期对变压器制造厂家选材和使用起到参考作用。