QUANTUM MECHANICS: Enhanced: Schrodinger's Cat Is Out of the Hat

In 1935, Erwin Schr?dinger suggested his famous gedanken experiment of the cat that is simultaneously "dead" and "alive" inside its box until the box is opened. But as Tesche explains in her Perspective, such a macroscopic manifestation of quantum mechanics has remained elusive until recently. The experiments by van der Wal et al. are an important step toward demonstrating that quantum mechanics can describe macroscopic phenomena. The approach may be exploited in quantum computing and quantum cryptography.     

Topological transitions in metamaterials

Light-matter interactions can be controlled by manipulating the photonic environment. We uncovered an optical topological transition in strongly anisotropic metamaterials that results in a dramatic increase in the photon density of states-an effect that can be used to engineer this interaction. We describe a transition in the topology of the iso-frequency surface from a closed ellipsoid to an open hyperboloid by use of artificially nanostructured metamaterials. We show that this topological transition manifests itself in increased rates of spontaneous emission of emitters positioned near the metamaterial. Altering the topology of the iso-frequency surface by using metamaterials provides a fundamentally new route to manipulating light-matter interactions.     

Coherence dynamics in photosynthesis: protein protection of excitonic coherence

The role of quantum coherence in promoting the efficiency of the initial stages of photosynthesis is an open and intriguing question. We performed a two-color photon echo experiment on a bacterial reaction center that enabled direct visualization of the coherence dynamics in the reaction center. The data revealed long-lasting coherence between two electronic states that are formed by mixing of the bacteriopheophytin and accessory bacteriochlorophyll excited states. This coherence can only be explained by strong correlation between the protein-induced fluctuations in the transition energy of neighboring chromophores. Our results suggest that correlated protein environments preserve electronic coherence in photosynthetic complexes and allow the excitation to move coherently in space, enabling highly efficient energy harvesting and trapping in photosynthesis.     

利用场耦合理论研究开放微波谐振腔

利用电磁场的等效原理,将一个开放微波腔等效于一个闭合边界微波腔（即封闭微波腔）和开放边界（即行波吸收边界）两部分,然后利用等效封闭微波腔的本征模式及其与开放边界的耦合,建立了关于开放微波腔模式（即模式场分布、频率、品质因子）的耦合方程组,其中开放边界为行波吸收边界.以X波段六腔渡越振荡管为例进行分析,将该振荡管等效为封闭微波腔和同轴输出结构两部分,用SUPPERFISH获得封闭腔的各个模式场分布及频率,然后根据封闭微波腔与开放边界的耦合,求得六腔渡越振荡管的工作模频率为9.25GHz,品质因子为115.2,与实验测量结果基本符合.     

Characterization of an extremely large, ligand-induced conformational change in plasminogen

Native human plasminogen has a radius of gyration of 39 angstroms. Upon occupation of a weak lysine binding site, the radius of gyration increases to 56 angstroms, an extremely large ligand-induced conformational change. There are no intermediate conformational states between the closed and open form. The conformational chang is not accompanied by a change in secondary structure, hence the closed conformation is formed by interaction between domains that is abolished upon conversion to the open form. This reversible change in conformation, in which the shape of the protein changes from that best described by a prolate ellipsoid to a flexible structure best described by a Debye random coil, is physiologically relevant because a weak lysine binding site regulates the activation of plasminogen.     

基于AutoCAD的任意复杂窗口裁剪技术

根据AutoCAD图形的特点及AutoCAD中已有的功能提出，将封闭的窗口定义成“面域（region）”参与裁剪运算，并给出了面域的自动生成方法；提出将被裁图形实体分成开环实体和闭环实体分别进行处理：对开环实体，利用ObjectARX提供的实体交函数实现了求交和排序同步完成；对闭环实体，组合使用“面域”的布尔操作实现窗口裁剪。综合以上技术编写的窗口裁剪程序模块具有结构简单，稳定性好的特点。     

开放式和封闭式TBS捕鼠效果观察

为探索TBS技术对害鼠的控制效果和作用,2015~2016年在贵州省安龙县旱地开展了开放式和封闭式TBS捕鼠对比试验,结果表明,开放式和封闭式TBS对鼠类都具有一定的控制效果,2个TBS围栏共捕获鼠形动物151只,种类有小家鼠、褐家鼠、黄胸鼠、鼩鼱4种。其中,封闭式TBS捕鼠58只,开放式TBS捕鼠93只,分别占捕鼠总数的38.41%,和61.59%,开放式TBS捕获鼠形动物数量明显多于封闭式TBS。不同安装方式鼠形动物组成基本一致,均以小家鼠数量最多。两种安装方式不同月份捕获鼠形动物数量不同,但变化趋势基本一致。不同月份捕获鼠形动物数量与试验周边生境、小气候及作物生育期有一定关系。     

Conformational switch of syntaxin-1 controls synaptic vesicle fusion

During synaptic vesicle fusion, the soluble N-ethylmaleimide-sensitive factor-attachment protein receptor (SNARE) protein syntaxin-1 exhibits two conformations that both bind to Munc18-1: a "closed" conformation outside the SNARE complex and an "open" conformation in the SNARE complex. Although SNARE complexes containing open syntaxin-1 and Munc18-1 are essential for exocytosis, the function of closed syntaxin-1 is unknown. We generated knockin/knockout mice that expressed only open syntaxin-1B. Syntaxin-1B(Open) mice were viable but succumbed to generalized seizures at 2 to 3 months of age. Binding of Munc18-1 to syntaxin-1 was impaired in syntaxin-1B(Open) synapses, and the size of the readily releasable vesicle pool was decreased; however, the rate of synaptic vesicle fusion was dramatically enhanced. Thus, the closed conformation of syntaxin-1 gates the initiation of the synaptic vesicle fusion reaction, which is then mediated by SNARE-complex/Munc18-1 assemblies.     

迈克耳逊干涉实验的设计新思路

通过薄透镜测焦距的实验装置组装一台迈克耳逊干涉仪,能将几何光学实验顺利过渡到波动光学实验,该方法对充分合理开发实验室资源,深刻理解物理概念和不同实验装置的设计思路很有益处。     

机械通风对鸡舍内NH_3浓度影响的研究

[目的]为科学养鸡提供参考依据。[方法]在风机开启与关闭状态下分析鸡舍内不同位置垂直方向上和不同高度水平方向上NH3浓度的变化,并定点监测NH3浓度随时间的变化。[结果]在整个鸡舍空间内,风机通风降低NH3浓度的量占风机关闭时浓度的比重最大值为69.3%,最小值为30.6%,而在定点位置处连续监测到的NH3浓度差占风机关闭时浓度比重的最大值为56.5%。[结论]机械通风可有效地降低鸡舍内NH3的浓度。     

Fluid transport and tubular intercellular spaces in reptilian kidneys

Renal tubules of crocodiles, lizards, snakes, and turtles have intercellular spaces similar in type to those observed in the mammalian gall bladder, but different from those of mammalian renal tubules. The fluid movements across renal tubules of reptiles are correlated with the width of the tubular intercellular spaces. In the proximal tubules, where transport is always isosmotic, the spaces are open whenever the tubular epithelium is tranporting, but closed when no transport is taking place. In distal tubules, intercellular spaces are wide open when the osmolality of the urine is close to that of the blood, that is, when the fluid resorbed is almost isosmotic to the tubular fluid. The apical two-thirds of the intercellular spaces are closed when the urine is hypoosmotic. They are also closed when the tubules are not transporting, as in collapsed tubules or tubules poisoned with ouabain. Thus, as in the gall bladder, the open intercellular spaces appear to be found whenever there is fluid transport across the epithelium.     

Ultrafast probing of core hole localization in N2

Although valence electrons are clearly delocalized in molecular bonding frameworks, chemists and physicists have long debated the question of whether the core vacancy created in a homonuclear diatomic molecule by absorption of a single x-ray photon is localized on one atom or delocalized over both. We have been able to clarify this question with an experiment that uses Auger electron angular emission patterns from molecular nitrogen after inner-shell ionization as an ultrafast probe of hole localization. The experiment, along with the accompanying theory, shows that observation of symmetry breaking (localization) or preservation (delocalization) depends on how the quantum entangled Bell state created by Auger decay is detected by the measurement.     

格氏栲林林窗更新特征的研究

通过格氏栲林林窗调查分析,格氏栲种群在林窗群落内与非林窗内同样占有最大的重要值,表明格氏栲对林窗更新反应不显著,均能在林窗内外更新.研究显示,格氏栲个体在林窗内呈集群分布,种群的直径分布呈贝塔分布,林窗边缘集中了较多的格氏栲植株;在年龄分布结构上,格氏栲在林窗和非林窗内株数比重高峰均出现于10年以下和70年以上,低峰出现于10～70年间,表明格氏栲林存在严重断代现象.因此在经营管理中,有必要人促更新.      

几种木本园艺植物塑料袋内密封扦插试验

本文报道在食品保鲜袋内密封扦插桂花、樱花、甜樱桃和苹果的试验结果。当年生半木质化至完全木质化插条经生根促进剂处理后，密封扦插在食品保鲜袋内的湿润基质上，放置空旷处，夏秋高温季节晴天适度遮阴。结果表明，塑料袋内的温度较稳定，基质始终保持刚扦插时的湿润状态，插条叶片全部或部分保持饱满、挺立。插条一周左右即可产生愈伤组织，３─４周便可出根。尽管在几种材料上获得的生根率差异较大，但都成功地生了根。在以“峨嵋仙土”为扦插基质，６月份晴天１０：００─１７：００时遮阴的条件下，樱花的生根率达７０％以上。     

Atomic memory for correlated photon states

We experimentally demonstrate emission of two quantum-mechanically correlated light pulses with a time delay that is coherently controlled via temporal storage of photonic states in an ensemble of rubidium atoms. The experiment is based on Raman scattering, which produces correlated pairs of spin-flipped atoms and photons, followed by coherent conversion of the atomic states into a different photon beam after a controllable delay. This resonant nonlinear optical process is a promising technique for potential applications in quantum communication.     

不同排湿方式热泵烤房烟叶烘烤效果评价

为测试闭式热泵密集烤房的烘烤效果，以中烟100为试验材料，利用开放式热泵密集烤房与闭式热泵密集烤房的对比试验，对两类烤房的烘烤工艺、排湿量、关键点温度差、烤后烟等级、经济性状及烘烤成本做了系统研究。结果表明：（1）闭式烤房的升温和排湿过程更加稳定，平面温差小，不同部位及成熟度烟叶烘烤耗电量和烘烤时长波动小。（2）闭式烤房烘烤排湿量在变黄和凋萎期、定色期、干筋期分别占比37%、47.93%、15.06%，排湿规律与开式烤房一致，均呈现出先增后减，定色期大量排湿的情况。（3）实验烤房中部叶及上部叶每公斤干烟成本较对照烤房分别降低了0.03元/kg、0.23元/kg。（4）闭式烤房烤后中部及上部烟叶均价分别提高2.6%、9.27%，上部烟叶上等烟比例提高7.4个百分点，柠檬黄烟比例有所提高，青杂烟比例明显降低，烤后烟叶外观质量有所提高，主要包括身份、油分、色度的改善。     

睡莲不同器官和不同生长阶段的过氧化物酶和酯酶同工酶比较

利用聚丙烯酰胺垂直板电泳技术对3个睡莲Nymphaea品种‘彼得’‘Peter Slocum’,‘玛珊姑娘’‘Masaniello’和‘得克萨斯’‘Texas Dawn’不同器官（未展开的幼叶、展开的幼叶、老叶、花瓣、花蕾、叶柄）和未展开的幼叶在营养生长阶段和生殖生长阶段的过氧化物酶（POD）和酯酶（EST）同工酶进行了研究。结果表明：①3个品种共有12种过氧化物酶酶带,6种酯酶酶带。②睡莲的过氧化物酶和酯酶具有组织特异性,其中未展开嫩叶和展开嫩叶的酶带最多,叶柄和花蕾次之,花瓣和老叶最少。未展开幼叶为较适合用于睡莲同工酶分析。③与生殖生长阶段相比,3个睡莲品种未展开幼叶在营养生长阶段的酯酶表达量更大,条带更多;而过氧化物酶同工酶表达量则是生殖生长阶段的表达量大,但3个品种的酶条带变化不一致,其中‘彼得’和‘玛珊姑娘’在生殖生长阶段的过氧化物酶同工酶阶段条带多‘得克萨斯’则相反。图4表3参15     

生物质燃料常温变径成型锥头研究

针对生物质常温闭式成型机的不足,本文引入了开式成型的概念,并在原有闭式成型机液压驱动设备的基础上,改进了成型腔.通过对生物质原料的力学分析,设计了开式成型的变径成型锥头.并使用小刨花、锯末等材料进行验证,探讨了对生物质常温变径成型机成型效果的影响因素,同时确定了较高成型质量时成型腔的压缩比范围.