}MSo浸种对大麦种子萌发及若干性状的影响

本文报道二甲亚矾(DMSO)浸种影响大麦“早熟3号”种子的萌发以及浸种后种子的渗漏和呼吸强度等的变化.结果表明:在24℃条件干浸种，。.1%和5芳的DMSO明显促进种子的萌发，5劣DMSO浸种的促进作用尤为明显.然而这种影响效应在zs c条件下浸种则完全相反，对种子萌发有抑制作用，表现明显的温度效应.     

Molecular dynamics simulations of the oligonucleotide with the modified phosphate/phosphonate internucleotide linkage

Impact of the internucleotide linkage modification by inserting a methylene group to the P-O bond (—O—PO ₂ ^— —O— chain changed for —O—PO ₂ ^— —CH₂—O—), on the modified oligonucleotide binding ability to the natural DNA strand was studied by molecular dynamics simulation. Complex of (dT)₁₁ with a deoxyadenosine undecamer containing alternating modified and natural internucleotide linkage was studied as a model system. The Amber force field was completed by a set of new parameters needed to model the modified part of the nucleotide. The simulations confirmed existence of a double-helical complex the melting point of which is considerably higher than 300 K. While the thymidine (unmodified) strand possesses a B-type secondary structure, the conformation of the adenosine (modified) strand is not stable at 300 K. The -ggt conformation of the modified linkages is highly preferred, temporary jumps to the -g-gt and ggt conformations were, however, observed.     

黄酮类天然产物13C NMR数据的计算机检索和辅助解析(Ⅱ)黄酮类天然产物的13C NMR数据规律及其在智能解析中的应用

本文通过对大量的黄酮类化合物¹³C NMR图谱的分析和研究,总结了不同类型的黄酮类化合物的¹³C NMR图谱特征及化学位移规律.对影响黄酮类化合物结构骨架上不同位置碳原子化学位移的因素进行了分析,建立了用于黄酮类天然产物¹³C NMR图谱智能解析的知识库.     

RANDOM EDGE can be exponential on abstract cubes

We prove that RANDOM EDGE, the simplex algorithm that always chooses a random improving edge to proceed on, can take a mildly exponential number of steps in the model of abstract objective functions (introduced by Williamson Hoke [Completely unimodal numberings of a simple polytope, Discrete Appl. Math. 20 (1988) 69-81.] and by Kalai [A simple way to tell a simple polytope from its graph, J. Combin. Theory Ser. A 49(2) (1988) 381-383.] under different names). We define an abstract objective function on the n-dimensional cube for which the algorithm, started at a random vertex, needs at least exp(const·n^1/3) steps with high probability. The best previous lower bound was quadratic. So in order for RANDOM EDGE to succeed in polynomial time, geometry must help.     

冈村枝管藻孢子体的形态和超微结构

从日本冲绳采回枝管藻，用毛细管将成熟多室孢子囊挑出，在试验室条件下培养，可长成孢子体．用光学显微镜和透射电子显微镜观察发现：孢子释放后形成盘状体附着在基质上，念珠状同化丝从盘状体中间分生．同化丝可从中间部位产生分支，多室孢子囊位于部分同化丝的近端部；同化丝大量产生后基部细胞平行排列，中空，形成假薄壁组织，而后孢子体进入伸长生长阶段；在每个盘状体细胞和同化丝细胞中都有多个色素体和线粒体，蛋白核突出于色素体其他部分，类脂体存在于类囊体中；在同化丝的细胞壁上存在缺口；对同化纤毛而言，色素体和线粒体数量少，紧贴细胞膜，质壁分离严重，在细胞壁上存在“通道”．     

基于CCD采集的Mach-Zehnder干涉条纹图的处理算法

Mach-Zehnder干涉仪适用于研究气体密度迅速变化的状态。由于气体折射率的变化与其密度的变化成正比,而折射率的变化将使通过气体的光线有不同的光程,因此可通过干涉臂变化对干涉条纹图像效果的影响得到气体密度。实测中,采用图像采集卡和CCD来接收Mach-Zehnder干涉仪产生的条纹图像,再通过计算机对条纹图像的条纹间距进行处理,从而得到气体密度的变化状态。从光干涉理论出发,对Mach-Zehnder干涉条纹图像特征进行了分析,建立了Mach-Zehnder干涉条纹的数学模型,并根据此模型设计了处理Mach-Zehnder干涉条纹图像的算法。算法包括图像的预处理(即图像的噪声提取)、图像的二值化及图像的细化。     

长江堤防工程地质信息处理模型及技术方法

长江中下游的主要防洪工程是长江干堤 ,长江堤防线路长、工程浩大、堤基工程地质水文地质条件复杂 ,涉及大量的已有地质数据和资料。今后在整治加固堤防的工程地质勘察工作中 ,还需随时进行数据的收集、存储、检索、分析、统计和维护 ,随时调用这些数据进行综合处理、编制报告和图件 ;在防汛期间可以针对堤防险工险段的险情 ,随时查询和调用有关的资料、数据或者图件 ,提供采取抢险措施决策的地质依据。这既提高了地质数据的利用价值和利用率 ,又保证了信息的准确性、完整性和共享性。因此 ,建立合理的长江堤防工程地质信息处理模型及其成熟的技术方法具有重要的意义。     

非晶硅薄膜的低温快速晶化及其结构分析

在镀铝的廉价玻璃衬底上高速沉积的非晶硅薄膜在不同的温度下退火10min.退火温度为500℃时,薄膜表面形成了硅铝的混合相,非晶硅薄膜开始呈现了晶化现象 退火温度为550℃时,大部分(约80%)的非晶硅晶化为多晶硅,平均晶粒尺寸为500nm 退火温度为600℃时,几乎所有的非晶硅都转化为多晶硅,其平均晶粒尺寸约为15μm.     

Effect of end groups on complexation kinetics between cyclodextrins and guest polymers

α‐Cyclodextrin (α‐CD) has been complexed with various poly(ethylene glycol) (PEG) derivatives in aqueous solution. It has been found that the end groups of PEG derivatives affect the complexation kinetics greatly, but have only a little influence on the thermodynamic behavior. By increasing the hydrophobicity of end groups, the complexation speeds up rapidly. On the other hand, the bulky end groups slow down the threading of polymeric guests into the cavity of CD. By changing the hydrophobicity and the size of end groups, the complexation rate can be adjusted in the range of several orders of magnitudes, which should be quite useful in the design of new supramolecular systems. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 2050–2057, 2006