基于三角面网格细化策略的改进种子填充算法

区域填充染色的一般解决方法并不适用于空间曲面.为解决该问题,提出一种适用于空间三角面网格的种子填充算法.通过改变种子点的判定方法,将平面种子填充算法扩展到空间三角面网格上,在细分三角面网格结构时,使用以轮廓线为引导的细分策略,并利用凸包的一些特殊性质对轮廓点进行筛选.实验结果表明,该算法可以较好地完成三角面网格的区域填充染色,在效率和填充效果方面都可以满足实际应用.     

An algorithm to build convex hulls for 3‐D objects

Abstract

In this paper, a new algorithm based on the Quickhull algorithm is proposed to find convex hulls for 3‐D objects using neighbor trees. The neighbor tree is the data structure by which all visible facets to the selected furthest outer point can be found. The neighboring sequence of ridges on the outer boundary of all visible facets also can be found directly from the neighbor tree. This new algorithm is twice as efficient as Barber's algorithm.     

New synthesis technique of supported ZSM-5 using organo-alumino-silicic gels

This contribution deals with the synthesis of a silicon-rich ZSM-5 obtained from an amorphous organo-alumino-silicic gel. The gel was formed by reacting a mechanical mixture of RHA (rice hull ash), silica’s source, and of natural clinoptilolite, source of alumina, with glycerol during 2 h at 200 °C. After a maturation period of one day at 60 °C, the reaction product was hydrolyzed by a tetra-propyl-ammonium (TPA) solution and then aged for two days at 135 °C in a stainless steel autoclave. After washing and drying, the X-ray pattern showed a well crystallized ZSM-5. The textural analysis of the slowly calcined solid at 500 °C for 4 h, and the SEM micrographies evidence that the zeolite was supported on mesoporous silica. The proportion of both components depends on the tunable hydrolysis conditions.     

Fatigue life prediction at a ship deck/superstructure intersection

Difficulties arise in identifying an appropriate method to predict fatigue life for the weld joint at the intersection of a ship's deck and superstructure. The problem relates to the gross stress concentration and rapidly changing stress at this location. Variations on the 'hot spot' stress approach to fatigue life analysis are reviewed, and applied to results from an experimental programme of fatigue tests on welded joints. Finally tentative recommendations are made for a procedure to predict fatigue life of the structure.     

高速赫尔槽在高速镀锡液中的研究应用

目的 方便快捷地研究高速电镀锡工艺,有效实现赫尔槽在高速镀锡液中的研究应用。方法 开发一种高速赫尔槽装置,以研究MSA高速镀锡工艺条件（温度、电流密度和流速）。采用增重法对不同电流密度下的镀液电流效率进行试验。通过扫描电镜和X射线衍射仪对镀层的微观形貌和结晶取向进行分析。结果 提高MSA镀锡电解液平行液流流速,工作电流密度可提高到40 A/dm2,电流效率仍达90%以上。MSA高速镀锡的电镀工艺为：流速>146 cm/s,温度40~60 ℃,电流密度20~40 A/dm2。经实验验证,平板电极中镀液流速与阴极极限电流密度存在正比关系,与旋转圆盘电极极限扩散电流密度公式相似。高速下沉积厚度相同的锡镀层,随着沉积电流密度的增加,镀层晶面择优取向由（220）晶面转变为（321）晶面。 结论 相较于在静态赫尔槽试验中研究电镀工艺对镀液性能的影响,该设计可更好地反映实际生产的真实情况,可应用于电镀试验和工厂生产的质量管理。     

基于正交试验的潜水器耐压壳体的结构优化设计

潜水器的质量大小直接影响其性能,设计时要求潜水器在满足强度、刚度等要求的前提下,要尽可能减小其质量。应用正交试验的方法来实现潜水器耐压壳体结构的优化,但用正交试验方法处理约束问题比较复杂。因此将以质量最小化为目标和以强度要求为约束条件的优化设计问题转化为无约束多目标的优化设计问题。得出各个参数对壳体的强度和质量的影响规律,最后运用综合平衡法得出最优的设计方案。     

基于水下清洗的舰船防污优化研究

将水下清洗与防污涂层性能的持续发挥联系在一起,分析了水下清洗延长防污涂层期效的过程,并以经济性为指标提出了优化分析方法,对水下清洗方式进行了比较,得出了空化射流水下清洗方式更有利于防污涂层性能的持续发挥。     

Frying performance of the hull oil unsaponifiable matter of Pistacia atlantica subsp. mutica

The anti‐rancidity effect of the hull oil unsaponifiable matter (USM, 100 ppm) of Pistacia atlantica subsp. mutica (Bene) on sunflower oil (SFO) during frying at 180 °C was investigated and compared to that of tert‐butylhydroquinone (TBHQ, 100 ppm). The unsaponifiable constituents of the Bene hull oil (BHO) were separated into hydrocarbons (3.7%), carotenes (3.6%), tocopherols and tocotrienols (24.7%), linear and triterpenic alcohols (0.9%), methylsterols (5.7%), sterols (3.2%), triterpenic dialcohols (4.7%), and triterpenic dialcohol methylesters (4.5%), by means of silica gel TLC. The results obtained from the measurements of total polar compounds, conjugated diene value, carbonyl value, and acid value during 32 h of frying showed that the frying stability of SFO improves more in the presence of the USM of BHO than in the presence of TBHQ. Moreover, compared to TBHQ, the USM had a better protective effect on the indigenous tocopherols of SFO during frying.     

Mean-square performance analysis of the family of selective partial update and selective regressor affine projection algorithms

In this paper we present a general formalism for the establishment and mean-square performance analysis of the family of selective partial update affine projection (SPU-AP), selective regressor affine projection (SR-AP), and selective partial update subband adaptive filter (SPU-SAF) algorithms. This analysis is based on energy conservation arguments and does not need to assume a Gaussian or white distribution for the regressors. We demonstrate through simulations that the results are useful in predicting the performance of these adaptive filter algorithms.