基于平行光管的星敏感器焦平面离焦距离检测设备设计及其误差分析

在星敏感器中,使用离焦成像的方式实现对恒星的成像,成像质量直接影响着测量定位精度。而星敏感器光学系统和图像传感器之间的离焦距离是寻找最优成像的重要参数。为了准确测得此离焦距离,设计了基于平行光管的星敏感器焦平面离焦距离检测设备,并针对设备设计原理中影响检测精度的各项因素进行误差分析。首先,在检测原理公式的基础之上,给出主要设计参数。其次,结合检测原理公式分析主要影响因素,即平行光管焦距误差、星敏光学系统焦距误差和直线位移台运动分辨率,并针对不同取值范围进行了仿真,验证了设计参数的理论合理性。     

GeO2纳米线的原位热氧化法制备与发光性质

以Au作催化剂通过金属锗与纯氧在600～800℃的氧化反应,在单质锗表面原位大面积生长出了GeO2纳米线．采用X射线衍射仪、扫描电镜和透射电镜对产物进行了表征分析．结果表明,GeO2纳米线为六方相单晶结构,其直径在65～600nm范围内,长度达50gm．研究了反应温度和喷金时间对纳米线直径的影响,提出了可能的生长机理．实现了不同直径GeO2纳米线的可控合成．发现发光峰位于355nm强的紫外光发光和发光峰位于400nm和485nm弱的蓝光发光,这两种发光可能分别起源于GeO2纳米线中氧空位与间隙氧之间的跃迁和氧空位中的电子与锗．氧空穴中心的空穴复合．     

一种实用的互联网络拓扑结构RP（κ）及路由算法

提出了一种基于Petersen图的互联网络RP（κ）。研究了该互联网络的性质，它具有良好的连接度、短的直径和简单的拓扑结构。在节点小于300的情况下，RP（κ）的直径低于Torus的直径，其最优分组的距离小于Torus最优分组的距离，特别是当分组节点数m满足6≤m≤100时，RP（κ）最优分组的距离近似等于Torus最优分组距离的一半。基于Petersen图结构，设计了点点通信、置换路由、广播路由和多对多路由算法，它们的通信效率分别为[k/2] 2,k 5,[k/2] 2和k 5。     

泥沙颗粒表面电荷分布的初步研究

泥沙颗粒表面电荷分布，是研究其与污染物之间吸附和解吸的基础．本文以石英砂颗粒为例，利用扫描探针显微镜（SPM）中的静电力显微镜（EFM）测量技术，用相位成像模式测量了石英砂颗粒表面的微形貌和电荷分布，并统计了两者间的关系．研究表明，石英砂颗粒表面形貌复杂，表面形貌对电荷分布影响较大，电荷大多集中在颗粒表面的鞍部、凸起和凹地部位，而在凹槽、凸脊和平坦部位分布较少．上述研究为揭示其吸附机理和进一步研究天然河流泥沙颗粒的相关性质奠定了基础．     

利用电子放射源测试小孔成像结构的角度响应

能量粒子的投掷角分布测量对于磁暴、粒子加速机制等空间物理理论研究和空间天气的准确现报和预报具有非常重要的意义．利用小孔成像技术和位置灵敏探测器构建的小孔成像探测器可用于测量能量粒子的投掷角分布．小孔成像探测器的角度响应标定一般需要特殊的设备，如专门设计的粒子加速器．这种粒子加速器必须具备如下特点：出射粒子能量在中能范围；粒子在测量时间内均匀出射；粒子出射方向一致；单位面积束斑内粒子数量足够低．介绍利用带准直器的90Sr／90Y电子放射源测量小孔成像探测器角度响应的方法，并利用Geant4软件进行了仿真计算．试验结果表明电子放射源标定实验结果与Geant4仿真计算结果符合度良好，验证了上述方法的有效性．     

洛斯阿拉莫斯国家实验室开发新型太赫材料

洛斯阿拉莫斯国家实验室的研究人员设计制造了一种能够操作太赫频率射线的装置。这种装置可能成为新型电子学和光子学应用的基础，应用到新的成像方法和先进通讯技术当中。这种太赫电磁频谱的范围在红外线和微波波长之间。     

距离对合成射流涡环撞击壁面的影响

利用二维PIV测速技术研究了射流孔口与壁面距离对合成射流涡环撞击壁面过程的影响,分析了涡环撞击壁面的演化规律,给出了流场的统计特性．研究结果表明,不同的孔口与壁面距离的差异,最终体现在涡环靠近壁面时涡量强度及撞击速度的差异;基于孔口直径的无量纲距离接近或小于合成射流无量纲冲程时,涡环撞壁会在壁面附近诱导产生二次涡结构．因此,合适的孔口与壁面距离对涡环撞击壁面效果起着至关重要的影响．流场统计特性分析表明,涡环撞壁后形成壁面射流,其时均速度最大值衰减速率和射流半宽度扩展速率随孔口与壁面距离的增加而减小．无量纲化的壁面射流速度型均表现出自相似特性,并且与壁面层流射流的理论曲线吻合较好．     

船用柴油机第一道活塞环岸积碳的微观形貌和孔隙特性的相衬显微CT研究

大型二冲程船用柴油机具有热负荷高、燃用重油、润滑油参与燃烧及其变质、颗粒物排放高等特点,直接或间接地导致其燃烧室内更为明显的积碳现象,同时积碳层的构成和特性会显著影响柴油机的输出动力性能和排放特性．采用我国第三代同步辐射装置一上海光源的x射线相衬显微CT技术,对第一道活塞环岸积碳样品进行了三维无损显微成像．通过定量数字图像处理,对积碳层的微观特性和孔隙分布特性进行了分析研究．结果表明,活塞环上部积碳厚度基本在1．0mm左右,仅为缸套和活塞间距的一半,但是其表面形态显示出与缸套强烈的摩擦磨损痕迹,这说明该部位的积碳会明显破坏缸套的滑油分布．同时积碳内外表面裂纹密集,而中部裂纹较疏松,积碳内外表面的裂纹形成机理存在显著差异．从孔隙连通性来看,几乎所有的裂缝都是相通的,计算得到的总的孔隙率在10．9％～12．8％之间．并且连通的裂纹中存在交汇的孔洞结构,这些孔隙结构可能对燃气产生吸附和解吸的作用．     

基于MAPC-RISR的MIMO雷达距离——角度二维超分辨率成像算法

MIMO雷达作为一种新型的雷达体制,其成像兼具实时性和高分辨率的特点,为了充分发挥MIMO雷达在成像方面的优势,提出一种高分辨率的MIMO雷达成像算法.首先将MIMO雷达成像过程分为距离向脉冲压缩和方位向聚焦成像两个过程,采用多波形自适应脉冲压缩技术(MAPC)实现距离向脉冲压缩和发射波形分离,然后在MIMO雷达虚拟阵列端利用超分辨率空间谱估计方法(RISR)进行方位向聚焦成像,得到了观测区域的距离—角度二维高分辨率的成像结果.理论分析表明,与已有的MIMO雷达自适应成像算法相比,所提方法降低了算法复杂度,提高了运算效率.仿真实验验证了所提MIMO雷达成像算法的有效性与优越性.     

基于压缩感知的多角度合成孔径雷达成像

多角度合成孔径雷达（syntheticapertureradar,SAR）成像是实现多SAR信息融合的重要方式．对提高成像分辨率．重构目标轮廓进而提高雷达目标检测或分类性能具有基础性价值．由于各传感器发射信号和测量位置的多样性,实现多角度SAR成像具有挑战性．如何在噪声干扰情况下快速实现多角度SAR成像是一个新问题．本文建立了基于压缩感知的多角度SAR测量模型．通过对测量矩阵的分析,证明多角度SAR测量角度范围、发射信号载频和空间采样位置是影响成像性能的关键因素,研究了目标空间离散间隔对成像质量和分辨率的影响．以上述分析为基础,本文对多角度SAR发射信号载频和测量位置进行设计,构建满足约束等距性的测量矩阵．针对测量矩阵阶次较高的问题,文章提出用分段正交匹配追踪（stagewiseorthogonalmatchingpursuit,STOMP）进行模型求解,在测量矩阵欠定严重的情况下,该算法可以迅速求得模型最优稀疏解．在实验环节．通过分析多角度SAR参数对成像性能的影响,进一步验证了本文结论．实验验证了模型和相应求解算法的有效性和鲁棒性．     

Oxygen permeability of the chorion in relation to diapause termination in Bombyx eggs

Oxygen permeability of the chorion of the silkworm, Bombyx mori, was measured in relation to embryonic diapause. It did not change appreciably when the eggs were freed from diapause by being kept under long chilling. This finding suggests that the increase in oxygen permeability of the chorion is not a pre-requisite for the termination of the diapause and resynthesis of glycogen from 2 polyols.     

Occurrence of sepiapterin deaminase in the normal type silkworm,Bombyx mori

Summary Sepiapterin deaminase was prepared from the normal strain of the silkworm, Bombyx mori. After inhibition experiments, this enzyme was found to have the same properties as that isolated from the lemon mutant strain. Several new inhibitors and their K₁ values are described for the deaminase.The authors wish to thank Dr Wm. Gyure, Cape Cod Hospital, Hyannis, Massachusetts, USA, for his help in preparing this report.     

Extracellular space values and intracellular ionic concentrations in the isolated midgut of Philosamia cynthia and Bombyx mori

Summary Total extracellular space values have been determined in the midguts of 2 lepidopteran larvae, Philosamia cynthia and Bombyx mori. The values found are 42% and 45% tissue water respectively. Intracellular concentrations of Na⁺, Ca⁺⁺ and Mg⁺⁺ are very low, while K⁺ concentration is 197.2 mEq/l cell water in Philosamia and 180.9 mEq/l cell water in Bombyx.     

Neuropeptides of the silkworm, Bombyx mori.

Six neuropeptides of the silkworm, Bombyx mori, have been isolated and chemically characterized during the past 10 years. They are bombyxin, prothoracicotropic hormone, pheromone-biosynthesis-activating neuropeptide/melanization-and-reddish-coloration hormone, diapause hormone, eclosion hormone, and adipokinetic hormone. Recent progress in research on these neuropeptides is described.     

Molecular cloning of the fibroin light chain complementary DNA and its use in the study of the expression of the light chain gene in the posterior silk gland of Bombyx mori

Fibroin light chain (L-chain) mRNA (mol. wt 4.0 X 10(5) daltons) was purified from the posterior silk gland of the silkworm, Bombyx mori (J-131 strain). Double-stranded complementary DNA was synthesized and inserted into the PstI site of pBR322 employing the oligo(dC)-oligo(dG) tailing method. Several recombinant plasmids containing the inserts of about 800 base pairs were isolated. Hybridization-translation assay demonstrated that these clones hybridized specifically with the fibroin L-chain mRNA. One of these clones (pLA23) was used as a probe to investigate relative concentrations of the fibroin L-chain gene and mRNA in the posterior silk glands at different stages of late larval development.     

Biochemical characterization and bacterial expression of an odorant-binding protein from <Emphasis Type="Italic">Locusta migratoria</Emphasis>

Analysis of soluble proteins from different body parts of Locusta migratoria revealed a fast-migrating component in native electrophoresis, unique to antennae of both sexes. N-terminal sequence analysis and cloning identified this protein as a member of the insect odorant-binding proteins, carrying a well-conserved six-cysteine motif. Mass spectrometry analysis confirmed the occurrence of two distinct polypeptide species determined by nucleotide sequencing and demonstrated that the cysteine residues are paired in an interlocked fashion. The protein was expressed in a bacterial system with yields of about 10 mg/l of culture, mostly present as inclusion bodies. However, this recombinant product was solubilized after disulfide reduction. Air oxidation yielded a species with all disulfides spontaneously formed as in the native counterpart. Both native and recombinant proteins migrated as a dimer in gel filtration chromatography. Ligand binding was measured, using N-phenyl-1-naphthylamine as the fluorescent probe; the affinity of other ligands was measured in competitive binding assays. The protein exhibited great resistance to thermal denaturation even following prolonged treatment at 100 degrees C. A structural model for this dimeric species was generated on the basis of its sequence homology with Bombyx mori pheromone-binding protein, whose three-dimensional structure has been resolved as an unbound species and in complex with its physiological ligand. This is the first report of an odorant-binding protein identified and characterized from Orthoptera.     

Propriétés chitinolytiques du liquide exuvial du ver à soie (Bombyx mori L.)

Summary The authors add further confirmation to the hypothesis of the role played by a chitinase during the process of moulting. By ligaturingBombyx mori-larvae between head and thorax, accumulation of moulting fluid takes place between the larval and nymphal cuticles, swallowing of this fluid being prevented. The chitinolytic properties of this moulting fluid are demonstratedin vitro. The activity of chitinase at different pH is investigated: the optimum pH lying at about 5.4.     

Quenching of intrinsic fluorescence accompanies the activation of prococoonase

Summary The intrinsic fluorescence of prococoonase fromBombyx mori is largely quenched upon its activation. The rates of fluorescence quenching and enzyme activation are equal, indicating that both reflect the same process.This work was supported by a grant from the National Research Council of Thailand.     

Localization of sucrase activity in the cocoon ofBombyx mori

Summary Enzymes capable of hydrolyzing sucrose, trehalose, lactose and cellobiose were detected in the cocoon ofBombyx mori. Sucrase activity was found to be highest and was present only in the outermost layer of the cocoon.     

Culturein vitro d'un tissu nymphal de lépidoptère

Summary Using a simplified medium, the composition of which is described in the text, cell cultures (fibroblast type) were obtained from nymphal ovarian tubes ofBombyx mori. The change in the form between fibroblasts and spindle cells is described. The preservation of activity of haemolymph congealed to – 20° C for a long time is shown; the advantages of using nymphs for cultivating tissues in virological series are also noted.