基于相位一致性的结构相似度图像融合质量评价方法

在红外(IR)图像和可见光CCD图像融合效果评价中,结构轮廓对人眼感知的影响非常重要,而相位一致性（PC）模型生成的PC图像很好地在红外(IR)图像和可见光CCD图像融合效果评价中,结构轮廓对人眼感知的影响非常重要,而相位一致性（PC）模型生成的PC图像很好地保留了结构轮廓特征,且不受图像亮度和对比度变化的影响。提出了基于PC的结构相似度（SSIM）图像融合质量评价方法;利用SSIM模型分别产生融合图像相对于IR图像和可见光CCD图像的SSIM图像;根据PC模型产生IR和可见光CCD各自的PC图像;根据人眼对轮廓和非轮廓区域的重视程度的不同,利用各自的PC图像对SSIM图像进行加权; 最终利用信息熵加权得到融合图像的评价指标。实验中,在对实验图像进行主观评价和多种客观评 价指标计算的基础上,首次计算了非线性相关系数和斯皮尔曼等级相关系数(SROCC),最后统计分析实验数据。实验结果表明该方法较以往评价方法具有更好的主客观一致性。     

支持向量机中核函数的性能评价策略

继神经网络方法之后,支持向量机成为机器学习领域中的有效方法,但是核函数的评价和选取问题一直存在。该文从结构风险出发,通过经验风险和置信区间2个方面对核函数的性能进行量化,给出评价核函数性能的公式,指出传统经验风险定义的缺陷,并提出了一个新的定义。实验证明了该算法的可行性和有效性。     

深海潜浮式提升舱的结构设计及水力学计算

基于深海采矿非连续输送模式,设计了一种潜浮式提升舱,用于海底多金属结核的运输.根据潜浮式提升舱的功能需求进行了总体结构及布局设计,并通过流体仿真软件对其进行了水力学仿真分析,研究不同海况下提升舱的受力情况.计算结果表明,提升舱水平运动时,以压差阻力为主,主体所受的阻力最大;提升舱竖直运动时,以声学仓迎流的姿态有利于减少...     

基于可信基点的结构化签名比较算法

提出了一种基于可信基点的结构化签名比较算法,对现有的结构化签名比较算法在基点初始化和传播过程中的不足进行了改进,并证明了改进的算法更可信.同时,通过增加循环属性、相同参数信息等方法作为新的划分属性来更细致地刻画函数信息,提高了可信基点在初始化和传播过程中的正确性和匹配率.还提出了一种启发式策略对比较结果是否存在错误匹配进行校验.     

具有混合约束的离散事件系统的Petri网控制器的研究

针对由Petri网建模的离散事件系统中具有混合约束的Petri网控制器的设计问题,利用局部设计和Petri网简化技术改进与完善控制器的设计方法,并证明所提方法是最大容许的.先利用局部设计Petri网简化技术把所有约束库所融合为一个与它们标识总量相等的库所,然后再与受约束的变迁进行对照比较,使控制器的设计更为简单并且避免了死锁,尤其是对规模较大的系统,其优势更加明显.针对于约束的不同情况,给出了相应的控制器设计方法,最后通过几个例子对该方法的简单性和有效性进行了验证.     

Effect of Structural Parameters on the Thermal Stress of a NiFe2O4-Based Cermet Inert Anode in Aluminum Electrolysis

Inert anode has been a hot issue in the aluminum industry for many decades. With the help of FEA(finite element analysis) software ANSYS,a model was developed to simulate the thermal stress distribution working condition of an inert anode. To reduce its thermal stress,the effect of some parameters on the thermal stress distribution was investigated,including the anode height,the anode radius,the hole depth,the hole radius,and the radius of inner chamfer and outer chamfer. The results showed that in the actual working condition of an inert anode,there existed a large axial tensile stress near the tangent interface between the anode and bath,which was the major cause of anode breaking. Increasing the anode height and reducing the hole depth properly seemed to be beneficial for the stress distribution. With the increase of anode radius,the stress distribution became better first and then deteriorated,the reasonable value was between 0.045 to 0.06m. The hole radius had a significant effect on the stress and a smaller radius would reduce the thermal stress. The effect of the radius of the inner chamfer and the outer chamfer was less than other parameters.     

航空遥感器光学窗口光机热一体化设计

为减小光学窗口对航空光学遥感器成像质量的影响,对光学窗口的窗口玻璃厚度进行了优化设计。根据强度理论确定了窗口玻璃最小厚度。依据纵掠平壁理论计算出光学窗口外表面的平均对流换热系数;以热光学为基础,仿真了航摄时光学窗口的瞬态温度场分布;计算了光学窗口在热-力耦合作用下不同窗口玻璃厚度时的波像差(PV和RMS),最终确定了矩形光学窗口(290 mm×140 mm)的玻璃厚度为17 mm。试验结果表明:特征频率为60 lp/mm时光学系统传递函数为0.304,并获得了稳定、清晰的航摄图像。成功实现了光学窗口的光机热一体化设计,可为其他航空光学窗口设计提供参考。     

多层间隔式结构多孔硅冷阴极电子发射的研究

在多孔硅（ＰＳ）表面电子发射冷阴极中采用间隔式多层结构。由此,器件电子发射效率显著提高,在３２．５Ｖ偏压下,发射效率达１３．５％,发射电流密度２９μＡ／ｃｍ＾２;工作电流和发射电流的波动性明显减小;器件稳定性得到提高。     

Bioinspired Fabrication of Superhydrophobic Graphene Films by Two‐Beam Laser Interference

Reported here is a bioinspired fabrication of superhydrophobic graphene surfaces by means of two‐beam laser interference (TBLI) treatment of graphene oxide (GO) films. Microscale grating‐like structures with tunable periods and additional nanoscale roughness are readily created on graphene films due to laser induced ablation effect. Synchronously, abundant hydrophilic oxygen‐containing groups (OCGs) on GO sheets can be drastically removed after TBLI treatment, which lower its surface energy significantly. The synergistic effect of micro‐nanostructuring and the OCGs removal endows the resultant graphene films with unique superhydrophobicity. Additionally, dual TBLI treatment with 90° rotation is implemented to fabricate superhydrophobic graphene films with two‐dimensional grating‐like structures that can effectively avoid the anisotropic hydrophobicity originated from the grooved structures. Moreover, the superhydrophobic graphene films become conductive due to the laser reduction effect. Unique optical characteristics including transmission diffraction and brilliant structural color are also observed due to the presence of periodic microstructures. As a mask‐free, chemical‐free, and cost‐effective method, the TBLI processing of GO may open up a new way to biomimetic graphene surfaces, and thus hold great promise for the development of novel graphene‐based microdevices.     

光纤传感器对混凝土结构钢筋腐蚀监测的研究

本文报道了光纤传感器用于混凝土结构钢筋腐蚀监测的实验研究结果。该传感方案基于用Fe-C合金膜局部取代光纤介质包层,构成腐蚀敏感膜,从而获取金属腐蚀信息。为了监测钢筋在实际混凝土结构中的腐蚀行为。本文提出了可以埋入到结构中的光纤腐蚀传感器（FOCS）,并对埋入工艺进行研究,通过人造裂缝将防冰盐（NaCl）溶液加入到混凝土结构钢筋处并进行加速腐蚀,用紧贴钢筋铺设的FOCS监测钢筋腐蚀过程中输出光功率的变化,结果表明FOCS输出光功率变化和腐蚀介质的pH值变化有良好的对应关系,并与腐蚀电化学理论描述相一致,证实了所提传感器方案的可行性。