用于大截面传像光纤束的折衍混合光学系统设计

在大截面传像束前置光学物镜设计中,采用“负-正”型式的像方远心光路结构,很好地解决了镜头轴外像差校正和像面照度均匀性问题,同时使镜头结构紧凑、小型化。给出了前置物镜设计实例:工作波长0.8~1.1μm,焦距5mm,相对孔径为1:3.84,光学长度为47mm,视场角为60°。在光学耦接镜设计中采用物方远心光路结构,引入二元光学透镜,通过理论计算和ZEMAX光学软件优化,给出工作波长0.8~1.1μm,焦距33.6mm,光学长度为63.5mm,采用一个衍射面的耦接镜设计实例。该设计结果适用于单丝直径16μm,截面直径6mm的光纤传像束。     

基于改进FS算法的反舰导弹导引头成像研究

针对开发巡航式反舰导弹雷达导引头成像功能这一问题,设计了导弹的典型飞行轨迹,并采用改进的聚束式SAR—FS成像算法在导弹飞行过程中对舰船目标进行成像。导弹飞行过程中,斜视角随之变化,在接近目标时逐渐增大,改进的FS算法引入了SRC的非线性变标对数据进行二次距离压缩,有效地减少了距离压缩误差,以达到较好的聚焦效果,提高成像质量。计算机仿真结果表明,在末端成像制导阶段,当斜视角达到以上时,改进的FS算法也能达到较好的成像效果,为完成攻击点的选择,提高角跟踪精度创造了条件。     

水下成像声呐探测系统建模与仿真

水下探测技术已成为几年来各国普遍重视发展的技术之一。为解决通过试验进行水下声呐成像探测研究的方法中存在的经济成本高、技术方法准确性不好把握等问题。该文采用数学建模和计算机软件仿真的方法,在进行水下成像声呐探测仿真系统的总体软件设计的基础上,对各子模块的算法的研究现状进行分析,重点分析了声呐图像生成、图像滤波、目标识别以及控制系统等单元,并给出了部分算法的数学模型和仿真结果。从而实现了水下成像声呐探测系统的模拟,为水下声呐成像探测技术的研究提供了一个经济实用、高准确度的研究平台。     

MRI图像的基于窄带的递进多分区C-V分割方法

提出了递进的基于窄带的多分区C-V方法,并对多幅医学脑部MRI图像进行了分割实验。由于该递进方法分为多个阶段,每阶段只需一个水平集函数,并且在每一阶段应用窄带区域,即只处理窄带区域中的点,从而使计算量大大减少。实验结果证明本算法是有效的,在提高计算速度的同时,可大大改进复杂几何结构的分割效果。     

VIS/NIR spectroscopy for non-destructive freshness assessment of Atlantic salmon (Salmo salar L.) fillets

Visible/near-infrared spectroscopy has been evaluated for use in freshness prediction and frozen-thawed classification of farmed Atlantic salmon fillets, where fresh samples were stored as whole fish in ice. A handheld interactance probe for performing rapid measurements of single fillets and an imaging spectrometer for online analysis at an industrial speed of one fillet per second, have been used. Freshness as storage days in ice is predicted with an accuracy of 2.4 days for individual fillets, whereas frozen-thawed salmon fillets are completely separated from fresh fillets. The prediction results are comparable to previous results using the Quality Index Method with trained panelists. The region between 605 and 735 nm, which excludes interference by carotenoids and water, is appropriate for both frozen-thawed classification and freshness prediction of salmon fillets. The results indicate that the spectral changes are explained mainly by oxidation of heme proteins during the freeze–thaw cycle and during chilled storage in ice.     

MRI研究泠冻馒头微波复热过程水分的迁移变化

普通新鲜馒头在-18℃的环境中冷冻24h后，取出进行微波解冻加热实验。利用核磁共振成像（MRI）技术研究冷冻馒头复热过程中水分的迁移变化。馒头在受热过程中水分的损失直接影响馒头的品质。实验比较了冷冻馒头在微波蒸碗不加水和加水两种方式下含水量的变化，发现微波蒸碗加水复热对馒头的水分有一定的补偿效果。     

Profiling and Imaging of Phospholipids in Brains of Abcd1‐Deficient Mice

ABCD1 is a gene responsible for X‐linked adrenoleukodystrophy (X‐ALD), and is critical for the transport of very long‐chain fatty acids (VLCFA) into peroxisomes and subsequent β‐oxidation. VLCFA‐containing lipids accumulate in X‐ALD patients, although the effect of ABCD1‐deficiency on each lipid species in the central nervous system has not been fully characterized. In this study, each phospholipid and lysophospholipid species in Abcd1‐deficient mice brains were profiled by liquid chromatography‐mass spectrometry. Among the phospholipid and lysophospholipid species that are significantly more enriched in Abcd1‐deficient mice brains, VLCFA were present in 75, 15, 5, 4, and 1 species of phosphatidylcholine, phosphatidylethanolamine, sphingomyelin, lysophosphatidylcholine, and lysophosphatidylethanolamine, respectively. Most VLCFA were incorporated at the sn‐1 position of phosphatidylcholine and phosphatidylethanolamine. Among the phospholipid species that are significantly less enriched in Abcd1‐deficient mice brains, odd‐numbered saturated or mono‐unsaturated fatty acyl moieties are contained in all phosphatidylcholine species. In addition, a number of phosphatidylglycerol, phosphatidylinositol, and phosphatidylserine species contained highly unsaturated fatty acyl moieties. Intriguingly, 44:1 phosphatidylcholine with VLCFA was mainly distributed in the gray matter, such as the cortex, but not in the white matter in the cerebrum and cerebellum. These results show that ABCD1‐deficiency causes metabolic alternation of long‐chain fatty acids and VLCFA. Moreover, our results imply a molecular mechanism for the incorporation of saturated or monounsaturated VLCFA into the sn‐1 position of phospholipids, and also indicate that the distribution of phospholipids with VLCFA may correlate with the development of X‐ALD.     

陶瓷砖表面质量视觉检测系统研究

重点介绍了机器视觉技术在陶瓷砖表面质量检测中的应用。系统采用面阵摄像机作为测量工具,应用方向算子进行对目标边缘的定位和跟踪,以便获得完整、精确、封闭的目标边缘。实现了对陶瓷砖的边直度、直角度、缺边和缺角等项目的非接触检测。     

复合材料深度方向超声C扫描检测技术

介绍一种基于超声传播时域特性的深度方向超声C扫描成象检测技术,一次扫描可以同时获取被测材料内部若干层的扫描检测图象。     

现代X光电子能谱(XPS)分析技术

现代电子能谱仪有3个主要功能:单色XPS(Mono XPS)、小面积XPS(SAXPS)和成像XPS(iXPS),被认为是光电子能谱仪发展方向。本文介绍这3个功能突出的特点及在材料微分析方面的实际应用。