基于Argo资料的深海温跃层对水声传播的影响分析与仿真

利用Argo网格化数据分析日本以南小范围海区内的温跃层时空特征,其主跃层和季节性跃层的双跃层结构明显。依此利用UMPE(University of Miami Parabolic Equation)抛物方程模型分析与仿真深海温跃层及其季节变化对水声场的影响。分析发现:相似系数为1的两个声速剖面的传播损失几乎完全相同;夏季声源较浅时,会在以声源为中心小直径圆形区域内形成声影区;声源深度相对于跃层越大,跃层对水声场的影响越小;高频较低频受跃层影响更大。     

利用残缺样本声速重构声速剖面

用经验正交函数(experiential orthogonal functions,EOF)表示声速剖面受限于样本声速的测量深度,应用该方法重构声速剖面只能计算到样本中最浅剖面的深度。要想进行全海深声速剖面的重构,必须对残缺的样本声速进行合理地外延。为此,首先对样本中温度和盐度进行了外延,然后根据声速经验公式计算得到了全海深的样本声速。在此基础上,通过解多元方程组的办法求解经验正交函数系数达到了声速剖面重构的目的。结果表明,提出的声速剖面外延方法是有效的。另外,只要知道声速剖面变化较剧烈深度上的3个点的声速值就能重构声速剖面,对于文中的数据来说,重构的均方根误差可达到0.872 m/s;增加经验正交函数的阶数能提高重构精度,但5阶以上,阶数的继续增加对精度的提高将不会有显著的影响。     

基于差分拉曼光谱对烟盒物证检验

目的 为了探究一种基于光谱分析的检验方法,以达到快速准确地区分检验烟盒物证的目的.方法 采用便携式差分拉曼光谱仪,对39个不同的黄色烟盒样本进行测试,取得各样本的差分拉曼光谱数据.根据烟盒填料种类对样本进行初步分类,再结合化学计量学,通过IBM SPSS Statistics 26.0软件,在主成分分析法对数据进行降维的基础上,对测量结果进行系统聚类和K-Means聚类.结果 39种样本依据填料种类可以区分为3类,结合化学计量学可以更准确地区分为6类.结论 该方法无损检材、快捷准确,且图谱不受荧光干扰,结合化学计量学方法可以对烟盒样本进行分类检验,此方法为公安机关在犯罪现场检验此类物证提供了依据.     

基于改进有序聚类法的立式加工中心进给系统温测点优化

为解决立式加工中心热误差补偿关键技术中温测点难选取的问题，提出了一种基于改进有序聚类法的机床进给系统温测点优化方法。首先，结合试验数据计算反映温测点温度变量与热误差相关性的互信息值，初步筛选机床各部件的温测点，消除测点间的耦合性；然后，根据筛选出的温测点，通过建立类直径矩阵和计算各类的最小误差函数，获得温度变量分类；最后，基于多元线性回归建立包含多个不同温测点的热误差模型，并对模型进行统计学综合分析，确定了最佳聚类数和最佳温测点。结果表明：在不同加工条件下采用改进有序聚类法建立的热误差模型的均方根误差和平均残差分别降至1.05 μm和1 μm以下，相较于采用传统有序聚类法和灰色关联度模糊聚类法建立的热误差模型，它具有更高的热误差预测精度和更好的鲁棒性。所提方法在中小型加工中心进给系统的温测点研究中具有广阔的应用前景。     

基于多元分类模型的颜料红外光谱鉴别

颜料的检验与认定是司法鉴定中一项重要的工作。在传统的分析中,侦查人员往往通过人工逐一比对和分析,其耗时长,误差大,无法满足无损、快速、准确检验现场颜料样本的需求。该文提出一种检验方法,以期实现对物证无损、快速、准确的检验与鉴定。通过采集并分析不同品牌共计48个颜料样本的红外谱图,采用多元散射校正、Savitzky-Golay平滑和峰面积归一化开展预处理工作,建立基于K近邻算法等4种分类模型,从而实现不同颜料间的区分和归类。在区分水粉类颜料和毕加索丙烯画颜料时,相较于K近邻和Fisher判别模型,多层感知器分类模型准确率更高(总体分类准确率为100%),分类结果更好。在经过主成分分析提取特征变量后,分类模型对两类颜料的区分准确率均为100%。应用MLP结合PCA构建的分类模型对颜料样本的区分效果最佳。针对水粉类中的两类即普通水粉类和毕加索水粉类颜料样本,多层感知器分类模型对其的分类准确率为97.2%,针对普通水粉类样本的两个品牌(贝碧欧和晨光),多层感知器分类模型的分类准确率为100%,实验结果理想。利用中红外光谱结合多元分类模型可实现对颜料样本准确的鉴别与区分,其快速无损准确,降低检验鉴定成本,提高检验鉴定效率,可为其他物证的鉴别与分析提供一定的参考。     

浅海声速剖面对吊放声纳探测距离的影响

吊放声纳的作用距离不仅和自身设备性能有关,还和海洋水声环境特性及吊放声纳入水深度有着密切的关系.本文阐述了浅海不同声速剖面中的声传播特性,通过仿真声线轨迹分析了几种典型的浅海声速剖面对声传播的影响.通过对声纳、水声环境以及目标的模型化计算,利用射线模型仿真了几种不同声速剖面情况下吊放声纳的主动作用距离.分析了吊放声纳入...     

差分拉曼光谱结合化学计量学对白色购物纸袋的检验研究

目的 建立差分拉曼光谱用于无损识别白色购物纸袋的方法。方法 对收集到的60种不同品牌、不同规格的白色购物纸袋进行拉曼光谱测定，对样品的拉曼光谱图进行预处理，根据光谱图对样品进行初步分类，并结合化学计量方法对样品进行分组。应用Fisher判别分析方法对分类结果进行验证。最后应用RBF模型对未知样本进行分类判别。结果 结合样品中所含的碳酸钙、滑石粉、硫酸钡的不同，可初步将白色购物纸袋样品分为五大类，采用K-均值聚类方法继续细分，通过Fisher判别方法对样品分结果进行验证，判别准确率为100%。应用神经网络RBF模型对未知样本进行判别分析，准确率达到89.48%。结论 该方法简便易行，为白色购物纸袋的分类提供了科学的依据，也为公安基层工作的开展提供了便捷的办法。     

一种基于分子结构设计理论的聚类分析方法

针对常用的无监督聚类分析方法中存在的问题,提出了一种基于分子结构设计理论的聚类分析方法。该方法借鉴分子结构设计理论模型,将故障样本空间看作分子系统,将故障样本看作分子系统中的原子,以故障样本之间的差异度作为分子势能的度量指标,在故障样本间"相互作用势"的影响下,以样本间"势能"最小为依据,调整故障样本在映射平面上的位置,从而获得最佳的聚类效果。开展了不同状态滚动轴承振动测试实验,聚类结果表明,相比于SOM聚类方法,该方法将聚类有效性指标DB值降低49.04%。将该方法应用于柴油机故障振动数据的聚类中,实验结果表明聚类效果良好,能够有效地将不同故障的数据区分开,验证了该方法的可行性和有效性。     

一个实时多路径定位系统

传统声呐与现代声呐信号处理的主要差别在于对声道所做的假设不同。前者假设声道的声速剖面是均匀的，后者假设声速剖面在水平面内是均匀的而在垂直面内的是非均匀的。正是由于对声速剖面所做的假设不同，使得我们可从声场中提取的信息也不同。传统的被动定位方法一般可分为两类，一类是三角定位法，它利用波前弯曲来定位，使得其受基阵孔径的约束较大，因此作用距离不可能太远；另一类是ＴＭＡ定位方法，这类方法均需较长时间的积累     

基于主元-双谱支持向量机的旋转机械故障诊断方法

提出一种基于主元-双谱支持向量机的旋转机械故障诊断方法，该方法具有对故障在线监测分类和故障分类能力强的优点，能有效地从汽轮机故障的非平稳、非高斯时变信号中提取状态特征。首先研究了直接法、间接法及ARMA模型法的双谱估计特征，然后利用双谱分析主元数字特征提取技术提取这些特征，最后利用支持向量机对汽轮机小样本故障进行分类，较好地解决了故障样本不足的实际问题。诊断结果表明与常用的BP神经网络相比可以获得较高的诊断精度。     

Effect of Permeable Crystalline Material on Steel Reinforcement Corrosion of Concrete

Permeable crystalline materialcan permeate into pores and cracks of concrete and catalyze the reaction between Ca(OH) 2and unhydrated cement to generate a great quantity needle non-soluble crystals, which can stop up the pores and cracks of concrete, and increase the impermeability of concrete. This paper reported the results of a study conducted to evaluate steel reinforcement corrosion of concrete specimens uncoated and coated with permeable crystalline material as well as mixed with the permeable crystalline material. The properties evaluated for corrosion test were water impermeability, water absorption, compressive strength and potential. The results of water impermeability, water absorption, compressive strength clearly showed that the permeable crystalline material could prohibit water, any soluble salts and moisture from penetrating the concrete to cause corrosion, leaking, and other problems, and it did increase the compressive strength, which was favorable for protection of corrosion of reinforcing steel. Moreover, it was concluded from the potential-time curve that the steel reinforcement of uncoated specimen was in the state of activation whereas that of other specimens coated and mixed with the permeable crystalline material was in the state of inactivation. Above all, it was indicated that the permeable crystalline materialis very effective to protect the steel reinforcement of concrete from corrosion.     

The Research and Application About "Dry Peeling Off" Technology for Airplane Surface Paint Layer

In this paper, the principle of spurting take off lacquer were introduced; and with orthogonal method the unsaturate polyester was prepared ;it was easy to peel airplane paint layer off with this material and equipment.     

Quality Study of Honeycomb Core Shaping Without Wax Stabilization

Sandwich panels utilizing honeycomb cores result in lightweight, high-strength units that are very rigid. Indeed, they give honeycomb panels the best strength-to-weight ratio of any construction type available. Conventionally, the wax is poured into the cell of the core to strengthen the structure and prevent the core from being crushed during milling. Much time and labor is required to wax, mill, and clean the cores. In this study, the process of pouring wax into the core was skipped. In other words, the cutter directly milled the core. Experiments showed that the compressive strength of the core produced without wax stabilization was only 3% lower than that of cores produced using the traditional method. In addition, the drum peel strengths of cores produced without wax stabilization were 38.4% higher than cores produced using the traditional method, in which residual wax seriously polluted the adhesive. It was also found that eliminating the wax process can reduce costs.     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

In-process thermal treatment of polylactic acid in fused deposition modelling

Polylactic acid (PLA) is one of the most widely used open source fused filament fabrication materials due to its ease of extrusion, biodegradability, and mechanical strength. The mechanical strength of PLA largely depends on the proper growth of its semi-crystalline structure, which can be severely impaired by a low rate of crystallization, particularly in open source printers. This can be further aggravated by the non-uniform thermal distribution of heat that causes improper curing among the extruded beads of the printing material. As a result, PLA printed on open source printers does not achieve the best mechanical properties. This research, for the first time, proposes an additive-free solution implemented through a detailed set of experimentation to improve the curing rate through in-process temperature variations to cure the joints among the beads. Scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy is used to confirm the improvements in the bead joints. This work is conducted in two phases of experiments. In the first phase, a full factorial ANOVA is used to investigate various process parameters and the important variables are used in the second phase to print test specimens in four different sets.     

Investigation of the Corrosion Behaviors of HVOF-Sprayed Carbide Cernet Coatings in Molten Al-Zn-Si Alloy Bath

In continuous hot-dip galvanization process the corrosion and chemical stability of the sink roll in the galvanizing bath are important problem which effects on the quality and productivity. In order to protect the sink roll the carbide cermet and/or ceramic coatings were deposited on the surface of the sink roll. The WC-, Cr3 C2-cermet coatings were deposited by high velocity oxygen fuel (HVOF) spray, respectively. The coating samples were immersed in molten Zn-alloy containing 50 wt % aluminum at 833 K for 24 hr and 144 hr, respectively. The inter-diffusion and inter-reaction of Zn, Al and elements in coating and corrosion behaviors of these coatings were investigated by XRD, SEM and EPMA etc. The corrosion mechanisms of the carbide cermet coatings and ceramic coatings in molten High Al-Zn-alloy were approached.     

Fundamental study of adhesion of ice to cooling solid surface (Discussion on influence of copper oxide layer on ice adhesion force)

In many situations, ice often adheres to a cooling solid surface, frequently causing serious accidents. It is critical to clarify the mechanism of ice adhesion to the cooling surface in order to prevent ice adhesion. In a past study, the shearing stresses of two kinds of test plates with a copper surface having the higher thermal conductivity were measured. The shearing stress corresponds to ice adhesion force. Both shearing stresses were significantly different; however, the cause remains unclear.Therefore, the present study focuses on an oxide layer as the main factor causing the difference of both shearing stresses; the influence of the oxide layer formed on shearing stress was discussed. And in the removal and reformation processes of the oxide layer, the time variation of the shearing stress was clarified. Moreover, the relationship between the state of the copper surface and the shearing stress was also clarified by surface analysis.     

＂Three Transformations＂ and Standardization

During his inspection in Henan Province in May, Chinese President Xi Jinping stressed to ＂push forward the transformation from China Speed to China Quality, from Made in China to Created in China, and from Chinese Products to Chinese Brand＂. The ＂Three Transformations＂ are the specific requirements and goal of China＇s national development in the context that market should play a decisive role in the allocation of resources.     

重塑标准推行格局 推动LED照明的普及（英文）

正When you are enjoying the green,energy-saving and healthy lighting of IKEA LED luminaire,you may not realize that most of IKEA’s LED bulbs are produced by the LED luminaire smart manufacturing system of Hangzhou Zhongwei Photoelectricity CO.,LTD(ZVISION).No longer enclosed in the laboratory,the product standards are brought into the factory workshop and even to the entire production process.Thus,the standards are promoted and applied in a favorable way by enterprises,benefitting consumers with high quality products.     

Chinese Experts Contribute to ISO＇s New Toy Standards

正The international standard,ISO 8124-6,Safety of toys–Part 6:Certain phthalate esters in toys and children’s products,was officially issued by ISO worldwide on August 15.It was the first time for Chinese experts to lead the ISO standard development in toys industry.The standard was drafted by a group of Chinese experts from SAC/TC for toys and relevant Chinese departments and finally completed by a dedicated international group of experts.ISO 8124-6 makes a substantive breakthrough in the aspects of the scope of toys,limitation of plasticizer types,control of test cost,accuracy of test,operation convenience,etc.,offering the operational guidance for toy manufactures and testing laboratories.