基于DoG检测图像特征点的快速二进制描述子

针对SIFT描述子实时性差和传统二进制描述子对尺度、旋转和视角变化鲁棒性差的问题,本文通过优化采样模式和添加灰度差分不变量比较测试进行改进,提出了一种鲁棒性更高的二进制描述子。首先,设计了一种尺度关联、编号标记的采样模式;然后,旋转采样模式中各采样点到特定位置,确保描述子尺度、旋转不变性;接着,分析了采样点点对模式对描述子的影响,选择使用机器学习训练后的128对采样点对;最后,选择灰度值比较测试及梯度绝对值和比较测试构建二进制描述子。实验中采用DoG检测图像关键点,结果表明:本文提出的描述子在描述子构建和描述子匹配上比SIFT描述子分别快84%和67%;在有视角变化的图像匹配上,准确率比传统的二进制描述子高3%~5%,召回率平均要高30%以上。本文提出的特征点描述方法适用于时间要求高的图像匹配领域。     

水性紫外光固化纳米透明隔热涂料的研制

合成了聚氨酯丙烯酸酯预聚物,添加预制的功能纳米粉体水性浆料,制备了水性紫外光(UV)固化纳米透明隔热涂料。研究表明,水性浆料的平均粒径为27.8nm,添加到预聚物中后涂料的平均粒径为38.8nm;从涂层的综合性能、成本等因素考虑,以隔热粉体的用量为4.2%、涂层厚度为8μm为宜,涂层玻璃的可见光透过率达80%,涂层玻璃比空白玻璃在平衡时的温度降低10℃以上,并具有很好的硬度、耐磨、耐水等基本性能。     

Proton beam writing and electroplating for the fabrication of high aspect ratio Au microstructures

We present an approach to fabricate tall high aspect ratio Au microstructures by means of proton beam direct writing. Combining proton beam direct writing and electroplating, we successfully produced gold structures with sub-micrometer lateral dimensions, structure heights in excess of 11 μm, and aspect ratios over 28. Sidewall quality of the Au structures was improved by lowering the process temperature to 20 °C when developing PMMA patterns with GG developer. The application of such structures as X-ray masks for deep X-ray lithography with synchrotron radiation was demonstrated.     

Development of elastomeric lab-on-a-chip devices through Proton Beam Writing (PBW) based fabrication strategies

In recent years, one of the most exciting developments in fluidic device applications is the rapid evolution of miniaturized micro- and nanofluidic systems, the so called “lab-on-a-chip” devices. These devices integrate laboratory functions into a single chip, and are capable of various biochemical analysis and synthesis, such as sample injection and preparation, single cell/molecule observation, bioparticle sequencing and sorting etc. The evolvement of lab-on-a-chip concept implies the use of novel fabrication techniques for the construction of versatile analytical components in a fast and reproducible manner. Endowed with unique three-dimensional fabrication abilities, Proton Beam Writing (PBW) [1], which is capable of producing nanometer scaled fluidic structures with smooth and straight side wall features, has a great potential to develop all sorts of polymer fluidic devices.In this paper, we describe the batch fabrication of Poly-dimethysiloxane (PDMS) elastomeric lab-on-a-chip devices utilizing PBW technique. A series of fabrication processes, involving PBW, nickel electroplating, soft lithography, polymer dynamic coating and hydrophilic treating, were modified and adopted in our work. Subsequent characterization of individual categories of channel devices was carried out for specific fluidic studies. Respective experimental procedures are presented and results are explained. The channel devices demonstrated good fluidic performance and functionality, suggesting their further application in more complex biological investigations, and the versatility of PBW in lab-on-a-chip development.     

Advanced applications in microphotonics using proton beam writing

Proton beam writing (PBW) is a powerful tool for prototyping microphotonic structures in a wide variety of materials including polymers, insulators, semiconductors and metals. Prototyping is achieved either through direct fabrication with the proton beam, or by the fabrication of a master that can be used for replication. In recent times we have explored the use of PBW for various advanced optical applications including fabrication of subwavelength metallic structures and metamaterials, direct write of silicon waveguides for mid IR applications and integrated waveguides for lab-on-a-chip devices. This paper will review the recent progress made in these areas with particular emphasis on the main advantages of using the PBW technique for these novel applications.     

中子时空动力学直接模拟方法研究与程序研制

直接模拟方法(DSM)是一种新的用于求解三维瞬态中子输运问题的方法.该方法通过直接模拟瞬态过程中系统内中子和缓发中子先驱核的动态行为来求解核反应堆动力学问题.由于该方法取消了现有方法的各种近似,具有普适通用性.本文在详细研究该方法的基础上,开发了相应的瞬态分析程序TMCC,并进行了算例的验证.     

CFD在核能系统分析中应用的最新进展

介绍了国内外计算流体力学(CFD)方法在核能系统分析中应用的最新进展.CFD已经可以应用到一些三维单相瞬态流动情况中,其中包括堆芯及组件内的流场模拟,以及堆芯外空腔和其他领域的模拟分析.CFD的应用还需要进行进一步验证和基准化,并需要针对CFD的应用方法进行研究,包括建立最佳实践导则(BPG).CFD程序还被用于与热工水力系统程序的多尺度耦合以及与中子物理程序的耦合.CFD程序在两相流领域的应用还处于初级阶段,在湍流和多相流的模拟中需要更进一步发展.     

某轻型车辆液力减震器活塞杆断裂失效分析

对发生断裂失效的某型轻型车辆液力减震器活塞杆进行断口失效分析。为查找失效原因对活塞杆根部的加工状态进行分析,同时对活塞杆根部有无过渡圆角的两种情况进行有限元应力分析。结果表明,活塞杆的断裂属于高周疲劳断裂,引起早期疲劳断裂失效的主要原因是因为活塞杆根部过渡截面未加工过渡圆角所造成的。与未加工过渡圆角时相比,加工有R5的过渡圆时可以使活塞杆根部的最大轴向应力下降36%。     

羧甲基葛根淀粉的制备及其流变特性的研究

研究了葛根淀粉羧甲基化改性的最佳条件以及羧甲基化改性对葛根淀粉流变学特性的影响。结果表明，在淀粉乳浓度为12％，一氯乙酸与淀粉的摩尔比为0．7，氢氧化钠与淀粉的摩尔比为1．4，温度为45℃，醚化反应时间为1．5h时，羧甲基化取代程度最大，取代度为1．42。对羧甲基淀粉流变学特性的研究表明，随淀粉溶液浓度的增加，溶液粘度也随之增加，添加蔗糖对溶液粘度影响不大，而添加氯化钠对溶液粘度有显著影响；在强酸强碱性条件下，溶液的粘度较低，而在中性条件下溶液粘度保持在高水平上；随溶液温度的升高，粘度以指数形式迅速减小。     

大豆皂苷的研究进展

综述了国内外大豆皂苷的研究进展,包括大豆皂苷的化学组成、理化性质、生理功能、分离提取及其在工业中的应用前景。