基于点云数据的增材制造模型结构优化方法

增材制造因其逐层累加的特点,在进行结构优化时,需要考虑悬垂结构在成形过程中正确成形,避免在过程中形成冗余支撑结构。提出了一种三维模型结构优化方法,利用点云数据方法对三维模型进行处理获得其轮廓特征,将模型按照不同特征分割,针对其不同外部特征建立对应的内部椭球结构,同时在其内部重新构建自支撑结构,以保证优化后的结构成形过程中不会因为结构特殊而生成额外的支撑。实验结果表明,以四个不同特征模型为例,提出的方法在保证实体模型性能的前提下,平均减少了16.4%的成形时间及12%的材料成本。

新球时代女子乒乓球技战术诊断指标体系的实证性比较研究

为更准确把握新塑料乒乓球实施后女子比赛技战术表现的主导性特征和规律,更高效地发挥技战术诊断在助力中国女队备战世界大赛、提升训练、参赛的科学化水平中的作用,运用文献资料、专家访谈、比赛观察等方法,对近30余年来前人所建构的颇具代表性的分段式诊断指标体系进行实证性比较研究。观察数据来源于奥运会、世乒赛、世界杯等3项赛事的决赛、半决赛和四分之一赛共146场比赛样本。研究结果表明:(1)新球时代,各分段式诊断指标体系均有一定的合理性,但比较而言,新三段式诊断指标体系最优,最准确地揭示了女子乒乓球技战术表现的基本特征和规律,是新球时代最具代表性、科学性和引领性的诊断指标体系。(2)新三段式诊断指标体系的发抢段包含第1、3、5板,接抢段包含第2、4板,相持段包含第5板之后各板。其中,发抢段和相持段近乎并列地对比赛制胜发挥着第一位的作用,接抢段发挥着第三位的作用。(3)第5板的段落归属不仅对各段尤其是发抢段和相持段对比赛制胜的影响至关重要,而且对新三段式诊断指标体系的科学性也有着重要影响。(4)得分率比使用率能更好地体现和评价运动员各段的比赛能力,具有更好的评价效能。

石油焦化学氧化法脱硫

采用化学氧化法对高硫石油焦的脱硫规律进行研究。以双氧水为氧化剂,甲酸、乙酸和丙酸为催化剂,考察了石油焦粒度、氧化剂体积与石油焦质量之比(液固比)、反应时间和反应温度等因素对脱硫效果的影响。结果表明,双氧水⁃甲酸氧化体系的脱硫效果最好,明显优于其他两种氧化体系,在石油焦粒度为100目、液固比为20 mL/g、氧化反应时间为18 h、反应温度为60℃的最佳工艺条件下,石油焦的硫质量分数由3.32%降至2.65%,脱硫率达到20.2%。

Occurrence of gonadtropins like substance in the thoracic ganglion mass of the mud crab, Scylla paramamosain (Crustacea: Decapoda: Brachyura)

The identification and localization of vertebrate follicle stimulating hormone （FSH） and luteinizing hormone （LH） in crustaceans may further elucidate the regulation mechanisms in arthropod repro-duction. Using immunocytochemical staining techniques, this study has localized vertebrate FSH-like and LH-like substances in neurons in the subesophageal and thoracic ganglia from the thoracic ganglion mass （TGM） of Scylla paramamosain （Crustacea： Decapoda： Brachyura）. Enzyme-linked immunosorbent assay （ELISA） has shown that the concentrations of both FSH-and LH-like sub-stances increased markedly in the TGM during the vitellogenic stage compared with that in the previtellogenic stage. These results indicate that substances resembling the vertebrate FSH and LH are present in S. paramamosain, and they may be involved in the development of the ovary as well as in ovulation.

Effects of biogenic amines on the testicular development in mud crabs Scylla serrata

The regulation of three biogenic amines over the reproductive neuroendoerine activity of the male Scylla serrata was investigated by in vivo injection and in vitro incubation. The testicular index, the ratio of the mature sections in testes, and the ratio of Type B cells in androgenic gland were taken as the quantitative indexes. The in vivo injections indicated that： 5-HT can significantly promote the testicular development and the secretion of the androgenic gland in S. serrata; DA can inhibit the testicular development, but no influence on the secretion of the androgenic gland was found; no significant difference was observed between the OA-injected group and the concurrent control group. In vitro incubations showed that： 5-HT can stimulate the secretion of the brain and the thoracic ganglia, thus accelerating that of the androgenic gland; however, neither OA nor DA showed any significant influence on the secretion of the brain and the thoracic ganglionic mass. As to the optic ganglia, the three biogenic amines hardly have any effect on its secretion. It is the first time to report the regulation of biogenic amines over the reproductive neuroendocrine of male crustaceans through vitro experiments. Results corroborate that 5-HT activates the brain and the thoracic ganglia to secret GSH first, then promote the testicular development through the activity of the androgenic gland.

基于分子动力学和扩展有限元的金属微胶囊破裂性研究

在树脂矿物复合材料中掺入微胶囊实现材料自愈得到了广泛应用,而新出现的金属微胶囊解决了传统微胶囊力学和鲁棒等性能较差的问题。但因金属微胶囊与基体间的界面力学性能尚未可知,使其破裂性无法确定,进而无法将金属微胶囊推广。针对这一问题,本文提出利用分子动力学方法对金属微胶囊的囊壁/树脂基体界面损伤演化过程进行模拟,获得界面力学性能。以此为基础,运用扩展有限元对金属微胶囊的破裂性进行分析,为金属微胶囊的运用提供研究指导和理论依据。研究结果表明:(1)分子动力学模拟囊壁/基体界面模型损伤演化过程可以分为初始变形、局部破坏和整体破坏3个过程;(2)囊壁/基体界面弹性模量为6.458 GPa,强度极限为62 MPa;(3)金属微胶囊只会在基体裂纹出现后破损,但破损时间早于基体裂纹到达金属微胶囊处。