糠虾复眼超微结构的观察

使用电子显微镜研究了糠虾（Mysis latreille）复眼的超微结构．透射电镜观察结果显示：晶锥由4个晶锥细胞组成,2个位于远端,电子较致密,另2个位于近端,电子较疏松,晶锥延伸至近端与感杆束相连;7个小网膜细胞组成复眼的感光系统,感杆束直径在远端过核切面约为7．8μm．糠虾复眼的超微结构显示其感光器结构较一般十足目动物为原始,胞质中的细胞器种类和数量较少,色素颗粒较大,形态不规则．     

Photonic structures in biology

Millions of years before we began to manipulate the flow of light using synthetic structures, biological systems were using nanometre-scale architectures to produce striking optical effects. An astonishing variety of natural photonic structures exists: a species of Brittlestar uses photonic elements composed of calcite to collect light, Morpho butterflies use multiple layers of cuticle and air to produce their striking blue colour and some insects use arrays of elements, known as nipple arrays, to reduce reflectivity in their compound eyes. Natural photonic structures are providing inspiration for technological applications.     

日本沼虾胚胎复眼发生的研究

应用光镜技术和透射电镜技术,研究了日本沼虾胚胎复眼的发生.在原肠期,胚区前端的外胚层细胞增殖形成视叶原基.发育至后无节幼体期开始形成视神经节.在前蚤状幼体早期胚胎出现复眼色素，同时构成复眼的细胞开始分化。前蚤状幼体晚期，复眼色素区扩大到复眼直径的一半。复眼由个眼构成，每个个眼由角膜、角膜生成细胞、晶锥、小网膜细胞等组成。超微结构显示，胚胎的复眼结构与成体的相似，但感杆束直径比成体小。至胚胎孵化，眼柄尚未发育完善。     

昆虫复眼视觉系统的计算机模拟

采用计算机技术与生物科学结合的方法来模拟昆虫复眼的视觉系统 .相对于其他实现方法 ,它的模拟结果更具有真实性和可视性     

Crystal structure of squid rhodopsin

Invertebrate phototransduction uses an inositol-1,4,5-trisphosphate signalling cascade in which photoactivated rhodopsin stimulates a G(q)-type G protein, that is, a class of G protein that stimulates membrane-bound phospholipase Cbeta. The same cascade is used by many G-protein-coupled receptors, indicating that invertebrate rhodopsin is a prototypical member. Here we report the crystal structure of squid (Todarodes pacificus) rhodopsin at 2.5 A resolution. Among seven transmembrane alpha-helices, helices V and VI extend into the cytoplasmic medium and, together with two cytoplasmic helices, they form a rigid protrusion from the membrane surface. This peculiar structure, which is not seen in bovine rhodopsin, seems to be crucial for the recognition of G(q)-type G proteins. The retinal Schiff base forms a hydrogen bond to Asn 87 or Tyr 111; it is far from the putative counterion Glu 180. In the crystal, a tight association is formed between the amino-terminal polypeptides of neighbouring monomers; this intermembrane dimerization may be responsible for the organization of hexagonally packed microvillar membranes in the photoreceptor rhabdom.     

红螯螯虾感光器Gqα的亚细胞定位

利用免疫细胞化学的方法和电镜技术观察红螯螯虾感光器中Gq蛋白α亚基的亚细胞定位,结果表明Gqα以膜结合形式定位于感杆束和以可溶性形式定位于细胞质中,Gqα定位的变化依赖于不同的光照条件.在暗适应后,Gqα主要分布于感杆束,细胞质中很少,感杆束与细胞质中胶体金颗粒的密度比为1.44±0.074;在(日)光适应后,密度比减少为0.61±0.021;在不同波长的光照处理后,Gqα定位有差异,感杆束与细胞质中胶体金颗粒的密度比由高至低,依次为绿光(1.64±0.046)、红光(1.28±0.036)、蓝光(1.16±0.111)和黄光(0.96±0.099).光调节的Gqα转位可能控制了能被视紫红质激活的Gq蛋白的数量.研究表明光波可影响感光细胞中膜结合和可溶性Gqα的比例,而这一结果可能是由被光激活的视紫红质的数量来控制的.     

Insects breathe discontinuously to avoid oxygen toxicity

The respiratory organs of terrestrial insects consist of tracheal tubes with external spiracular valves that control gas exchange. Despite their relatively high metabolic rate, many insects have highly discontinuous patterns of gas exchange, including long periods when the spiracles are fully closed. Two explanations have previously been put forward to explain this behaviour: first, that this pattern serves to reduce respiratory water loss, and second, that the pattern may have initially evolved in underground insects as a way of dealing with hypoxic or hypercapnic conditions. Here we propose a third possible explanation based on the idea that oxygen is necessary for oxidative metabolism but also acts as a toxic chemical that can cause oxidative damage of tissues even at relatively low concentrations. At physiologically normal partial pressures of CO2, the rate of CO2 diffusion out of the insect respiratory system is slower than the rate of O2 entry; this leads to a build-up of intratracheal CO2. The spiracles must therefore be opened at intervals to rid the insect of accumulated CO2, a process that exposes the tissues to dangerously high levels of O2. We suggest that the cyclical pattern of open and closed spiracles observed in resting insects is a necessary consequence of the need to rid the respiratory system of accumulated CO2, followed by the need to reduce oxygen toxicity.     

Light-cone-like spreading of correlations in a quantum many-body system

In relativistic quantum field theory, information propagation is bounded by the speed of light. No such limit exists in the non-relativistic case, although in real physical systems, short-range interactions may be expected to restrict the propagation of information to finite velocities. The question of how fast correlations can spread in quantum many-body systems has been long studied. The existence of a maximal velocity, known as the Lieb-Robinson bound, has been shown theoretically to exist in several interacting many-body systems (for example, spins on a lattice)--such systems can be regarded as exhibiting an effective light cone that bounds the propagation speed of correlations. The existence of such a 'speed of light' has profound implications for condensed matter physics and quantum information, but has not been observed experimentally. Here we report the time-resolved detection of propagating correlations in an interacting quantum many-body system. By quenching a one-dimensional quantum gas in an optical lattice, we reveal how quasiparticle pairs transport correlations with a finite velocity across the system, resulting in an effective light cone for the quantum dynamics. Our results open perspectives for understanding the relaxation of closed quantum systems far from equilibrium, and for engineering the efficient quantum channels necessary for fast quantum computations.     

多层曲面仿生复眼成像系统的设计

针对单层曲面仿生复眼的子眼数目多, 难以加工以及所能达到的视场角较小的问题, 提出一种多层曲面仿生复眼结构。经过计算与分析得到, 当边缘子眼与中心子眼的光轴夹角为66.8°, 子眼的视场角为74.5°时, 利用7个子眼通道可实现仿生复眼系统180°范围内无盲区的成像, 减少了多个子眼复杂的加工过程。对单个子眼通道进行优化设计, 使其成像质量满足使用要求。实验表明, 该多层曲面仿生复眼结构能实现180°视场的成像, 且无成像盲区。     

导出化学势的简明方法

本文从均匀单质的开放体系出发,简单而有效地导出了化学势,然后将其运用到闭合体系和体系的化学平衡中去,并对在各种限定条件下的化学平衡方程进行了讨论。     

在任意初值下的受扰非线性系统PD型迭代学习控制与方法

对于一类非线性系统,在有界的初态干扰和输出干扰的情况下,提出了一种开闭环PD型迭代学习算法。系统在初值任意的情况下,进行初态学习的开闭环PD型迭代学习控制,并且推导出了关于初态学习的收敛性的充分条件。通过与开环PD型和闭环PD型迭代学习算法作对比来进行仿真验证,仿真结果验证了算法的有效性。     

电力系统神经网络逆控制中的闭环控制器设计

由于实际电力系统输入限幅、工作区域受限等因素的影响,采用神经网络逆系统方法对被控电力系统进行反馈线性化解耦后的复合系统并非理想的解耦线性系统.在对此复合系统设计闭环控制器时需要确定合理的期望响应特性.本文通过对被控电力系统的输入输出特性分析,得到线性化解耦后各子系统的主导物理特性,从而为确定合理的闭环期望响应特性提供依据.结合神经网络逆系统方法在励磁与汽门系统线性化解耦控制中的应用,本文给出了详细的设计方法与计算机仿真结果.     

多输入灰色控制系统的状态反馈问题

本文提出了一种利用非线性规划来确定灰色系统反馈阵K的设计方法。其特点是充分利用已知的信息,使闭环系统对开环灰矩阵A((?))的平均白化阵有希望的极点,对任意可能的偏差阵,希望极点的变化尽可能的小,当不确定性最差时,系统具有稳定性。     

Open-to-closed transition in apo maltose-binding protein observed by paramagnetic NMR

Large-scale domain rearrangements in proteins have long been recognized to have a critical function in ligand binding and recognition, catalysis and regulation. Crystal structures have provided a static picture of the apo (usually open) and holo usually closed) states. The general question arises as to whether the apo state exists as a single species in which the closed state is energetically inaccessible and interdomain rearrangement is induced by ligand or substrate binding, or whether the predominantly open form already coexists in rapid equilibrium with a minor closed species. The maltose-binding protein (MBP), a member of the bacterial periplasmic binding protein family, provides a model system for investigating this problem because it has been the subject of extensive studies by crystallography, NMR and other biophysical techniques. Here we show that although paramagnetic relaxation enhancement (PRE) data for the sugar-bound form are consistent with the crystal structure of holo MBP, the PRE data for the apo state are indicative of a rapidly exchanging mixture (ns to mus regime) of a predominantly ( approximately 95%) open form (represented by the apo crystal structure) and a minor (approximately 5%) partially closed species. Using ensemble simulated annealing refinement against the PRE data we are able to determine a ensemble average structure of the minor apo species and show that it is distinct from the sugar-bound state.     

基于对称变换的瞳孔定位方法

为解决瞳孔检测中眼镜反光、眼帘遮盖、闭眼等问题,提出了一种基于改进对称变换的
瞳孔定位方法。根据人脸的梯度信息、人眼瞳孔区域与眼镜反光区域梯度方向不同的现象,
改进对称变换算法,以提高定位准确性,采用自评估算法对定位进行评估,并利用自采
集的图像和图库中的图像进行了实验。结果表明,改进的对称变换算法能对瞳孔进行精确定位。     

刀额新对虾复眼的外部形态结构及光、暗适应对其超微结构的影响

应用电镜技术观察了刀额新对虾复眼的形态结构以及光、暗适应对其超微结构的影响．结果表明，刀额新对虾复眼外形呈圆球形，约由93116个小眼组成，组成复眼的小眼面均为正方形．每个小眼由折光系统和感光系统组成．光、暗适应时折光系统的结构基本相同，但感光系统之间有较大的差异．暗适应时，组成感杆束的微纤毛排列整齐，膜下储泡囊数量多，体积大，色素颗粒仅分布在细胞体远端；而光适应时，组成感杆束的微纤毛排列凌乱，并有部分溶解，多囊体多，各个层面上有板膜体的出现，色素颗粒分布于整个细胞．     

莱州湾凹陷油气成藏动力学特征

莱州湾凹陷是渤海海域勘探的新区.通过对莱州湾凹陷温压场、应力场、流体势分析,结合该区油气成藏地质条件,莱州湾凹陷明下至沙四段成藏动力学系统可划分为自源高压封闭、混源常压半封闭、他源常压开放3类成藏动力学系统;成藏动力特征决定了莱州湾凹陷油气以断层运移、垂向运聚为主.北部陡坡带和中央构造带自源高压封闭、混源常压半封闭成藏动力学系统为下阶段勘探的主要目的层系,次之为东部走滑带他源常压开放成藏动力学系统.     

暗适应和光适应时三疣梭子蟹光感受器超微结构的比较

用透射电镜研究了暗适应和光适应的三疣梭子蟹（Portunus tritubereulatus）光感受器的超微结构．结果显示出暗适应时,感杆束的直径大,微绒毛整齐,膜下潴泡囊的体积较小,线粒体、内质网等细胞器较多,色素颗粒位于细胞各处．在光适应时,感杆束的直径小,微绒毛凌乱,膜下潴泡囊的体积较大,板膜体、多囊体、溶酶体等细胞器较多,色素颗粒位于细胞远端接近细胞核层面;另外,微绒毛基部的胞饮泡数量、递质样颗粒以及其他细胞器的分布,暗适应和光适应的光感受器也有着较明显的差异．     

水下缆索动力学理论模型

水下缆索建模是水下拖曳系统和系泊系统中一项关键工作，采用多体系统方法对缆索动力特性进行理论分析，建立了缆索多体动力学三维有限段模型。该模型将缆索视为一系列具有不同物理特性的铰接刚性缆段，系统包含多个开环分支或闭环分支，讨论了流体阻力、流体附加质量和流体静压力的影响，分析比较了附加质量与系统本身惯性的关系，对小尺度缆索进行动力学仿真，并与实验结果做了比较，吻合良好，该模型可用于水下缆索系统的动力学仿真。     

基于复杂网络的三种眼睛状态下脑功能连通性比较

尝试构建不同眼睛状态下的静息态脑功能网络,研究睁眼、闭眼和自由状态下的大脑网络拓扑结构差异.招募了13例被试者,用一台3T的西门子磁共振仪,获取了3种眼睛静息状态下各8min的功能磁共振数据,并同时采集了结构像.随后,构建3组被试者的功能连通矩阵,计算其复杂网络的全局特征系数、局部特征系数等测度参数.对测度进行方差分析与双样本t检验,以统计分析被试者之间的差异.我们发现,所有的状态在合适的稀疏度下,展现了小世界特性;相比于其他状态,闭眼状态下的全局效率较低.自由状态在复杂网络的各项测度上接近睁眼状态.综上所述,该项研究展现了睁眼、闭眼、自由状态对人脑功能连通网络的影响,并为眼睛状态如何影响功能磁共振实验提供了关键的证据.