A Numerical Study for Turbulent Flow and Thermal Influence Over Inhomogenous Canopy of Roughness Elements

A large-eddy simulation with transitional structure function(TSF) subgrid model we previously proposed was performed to investigate the turbulent flow with thermal influence over an inhomogeneous canopy, which was represented as alternative large and small roughness elements. The aerodynamic and thermodynamic effects of the presence of a layer of large roughness elements were modelled by adding a drag term to the three-dimensional Navier-Stokes equations and a heat source/sink term to the scalar equation, respectively. The layer of small roughness elements was simply treated using the method as described in paper (Moeng 1984, J. Atmos Sci. 41, 2052-2062) for homogeneous rough surface. The horizontally averaged statistics such as mean vertical profiles of wind velocity, air temperature, et al., are in reasonable agreement with Gao et al.(1989, Boundary layer meteorol. 47, 349-377) field observation (homogeneous canopy). Not surprisingly, the calculated instantaneous velocity and temperature fields show that the roughness elements considerably changed the turbulent structure within the canopy. The adjustment of the mean vertical profiles of velocity and temperature was studied, which was found qualitatively comparable with Belcher et al. (2003, J Fluid Mech. 488, 369-398)'s theoretical results. The urban heat island(UHI) was investigated imposing heat source in the region of large roughness elements. An elevated inversion layer, a phenomenon often observed in the urban area (Sang et al., J Wind Eng. Ind. Aesodyn. 87, 243-258)'s was successfully simulated above the canopy. The cool island(CI) was also investigated imposing heat sink to simply model the evaporation of plant canopy. An inversion layer was found very stable and robust within the canopy.

The interaction between poly(vinylpyrrolidone) and reversed micelles of water/AOT/n-heptane

The interactions between poly(vinylpyrrolidone) (PVP) and the reversed micelles composed of water, AOT, and n-heptane are investigated with the aid of phase diagram, measurements of conductivity and viscosity, Fourier transform infrared (FTIR) spectrum, and dynamic light scattering (DLS). The phase diagrams of water/AOT/heptane in the presence of and absence of PVP are given. The conductivity of the water/AOT/heptane reversed micelle without PVP initially increases and then decreases with the increase of water content, ω0 (the molar ratio of water to AOT), while the plots of conductivity (K) versus ω0 of the reversed micelle in the presence of PVP depend on the PVP concentrations. The plot of K versus ω0 with 2.0%wt PVP is similar to that without PVP. Only the ω0,max (the water content that the maximum conductivity corresponds to) is larger than that without PVP. Nevertheless, the conductivity of the reversed micelle containing more than 4%wt PVP always rises with the increase of the water content in the measured range. The DLS results indicate that the hydrodynamic radius (Rh) in the presence and absence of PVP rises with the increase of ω0. The plots with PVP and without PVP have almost the same value when ω0<17; and after that, it quickly increases with the increase of ω0. It is interesting to find that there is almost no effect of the PVP concentration on the viscosity and Rh of the reversed micelle at ω0 = 15. The FTIR results suggest that the contents of SO3--bound water and Na+-bound water both decrease with PVP added, while the content of the bulky-like water increases. However, the trapped water in the hydrophobic chain of the surfactant is nearly unaffected by PVP. It is also found from the FTIR that the carbonyl group stretching vibration of AOT is fitted into two sub-peaks, which center at 1740 and 1729 cm-1, corresponding to the trans and cis conformations of AOT, respectively.

Highly sensitive wave-front sensor with a non-zero-order phase plate

We propose a novel highly sensitive wave front detection method for a quick check of a flat wave front by taking advantage of a non-zero-order pi phase plate that yields a non-zero-order diffraction pattern. When a light beam with a flat wave front illuminates a phase plate, the zero-order intensity is zero. When there is a slight distortion of the wave front, the zero-order intensity increases. The ratio of first-order intensity to that of zero-order intensity is used as the criterion with which to judge whether the wave front under test is flat, eliminating the influence of background light. Experimental results demonstrate that this method is efficient, robust, and cost-effective and should be highly interesting for a quick check of a flat wave front of a large-aperture laser beam and adaptive optical systems. (c) 2005 Optical Society of America.

中国晚泥盆世两种木本石松植物的研究

木本石松植物在晚古生代植物群中一直引人注目，它们是最早在中、晚泥盆世发展乔木和异孢习性的陆生维管植物谱系之一。在这篇报告中，中国两种晚泥盆世（距今约354-370百万年）的木本石松植物被详细地研究了。这两项研究增进了我们对泥盆纪木本石松植物的进化发育生物学的认识。 作者从中国西北部新疆准噶尔盆地上泥盆统的地层中描述了一个新种新疆鳞孢穗Lepidostrobus xinjiangensis sp.nov.，它为我们研究晚泥盆世石松植物的生殖分化和系统发育关系提供了新的认识。这个孢子叶球不同于任何草本石松植物的生殖器官，而与木本石松植物的生殖器官更为相似，它符合鳞孢穗属Lepidostrobus的鉴别性状。它的每个孢子叶由一个楔形的叶柄和一个三角形的叶片构成。孢子叶水平地着生在穗轴上，呈低角度的螺旋排列。叶柄具有侧翼和一个远轴面的脊，其远端延伸为一个上翻的叶片和一个下翻的踵，形成了一种盾状的外貌。孢子囊呈辐向加长、背腹扁的卵球形，具有顶端的纵向开裂。每个孢子囊基部纵向着生在叶柄的近轴面上。在孢子囊中发现了一个柱状的亚孢原组织垫。一个可能的叶舌出现在叶柄近轴面靠孢子囊远端。这个生殖器官是一个小孢子叶球，含石松孢Lycospora型孢子，具有粒状纹饰和赤道凸缘。基于这个鳞孢穗新种，木本石松植物从泥盆纪到石炭纪以来的生殖分化和演化式样在一个系统发育的框架中被讨论了。作者提出，木本石松植物由两性孢子叶球和单孢子叶球所代表的生殖策略到了晚泥盆世已经发展得相当完备，这暗示着系统发育上生有鳞孢穗孢子叶球的木本石松植物比过去所认为得起源要早。 作者重新调查了一个过去描述于中国湖北晚泥盆世（弗拉斯期）黄家磴组地层中的斜方薄皮木Leptophloeum thombicum的树干，并提出关于这个木本石松植物生长结构的新观点。这个树干保存为压扁的硅化化石，具有不均匀渗矿化的初生维管组织和螺旋排列的斜方形叶座。叶座特征符合晚泥盆世广泛分布的植物斜方薄皮木Leptophloeum rhombicum Dawson的鉴别性状。分类上，斜方薄皮木被归入薄皮木科Leptophloeaceae和广义水韭目Isoetales s.l.。这个树干在不同水平的解剖特征证明，斜方薄皮木的个体发育可能符合一种有限的生长方式。结合过去的资料和当前的生长结构分析，作者提出斜方薄皮木具有假单轴分枝的习性，而不是过去所认为的那样长着等二叉分枝的树冠。作者重新复原了这个植物的总体生长形态，它由一个根座式根状茎、一个主干和侧枝三类主要的生长结构单元构成。当这些结果组合了近期的系统发育工作后，它表明斜方薄皮木已经发育了与一些晚泥盆世法门期和石炭纪木本石松植物相似的生长结构，可能代表了早期水韭目植物祖先的生长结构类型之一。

大蹼铃蟾抗精子多肽及其制备方法和在制药中的应用

大蹼铃蟾抗精子多肽及其制备方法和在制药中的应用，属生物医学领域。大蹼铃蟾抗精子多肽，其在聚丙烯酰胺凝胶多肽电泳上的表观分子量还原和非还原条件下为8000Da，等电点8.8；其N－端20个氨基酸残基序列是：AVITGVICRRAQCGVGCAER。制备方法是将活体大蹼铃蟾清洗干净，经收集皮肤分泌物、离心去除沉淀、冷冻干燥、离子交换、凝胶过滤纯化等工序后得到。大蹼铃蟾抗精子多肽具有较强的精子制动活性和丝氨酸蛋白酶抑制活性，作为制备避孕药物和制备治疗胰腺炎及其他炎症药物的应用。

无指盘臭蛙分泌肽及其基因和在制药中的应用

本发明涉及一种无指盘臭蛙分泌肽及其基因和在制药中的应用，属于生物医学领域。该活性多肽是从中国两栖类动物无指盘臭蛙基因编码的一种环状多肽，分子量1587.98道尔顿，等电点9.7，多肽全序列一级结构为： Phe Met Pro Ile Leu Ser Cys Ser Arg Phe Lys Arg Cys，其第七位半胱氨酸和第十三位半胱氨酸相成分子内二硫键。编码无指盘臭蛙分泌肽的基因由300个核苷酸组成，其中编码成熟无指盘臭蛙分泌肽为第138-177位核苷酸。人工合成的无指盘臭蛙分泌肽具有显著的抑制细菌和真菌生长的作用，可以作为制备病原微生物感染疾病的治疗药物被应用。本发明的无指盘臭蛙分泌肽具有结构简单、人工合成方便、抗菌谱系广的有益特点。

从细胞色素b基因序列变异分析中国鲇形目鱼类的系统发育

采用PCR技术获得中国鲇形目鱼类 1 1科 2 4属 2 7个代表种类细胞色素b基因 1 1 3 8bp全序列 ,比较分析了来自北美洲、非洲的部分鲇形目鱼类同一基因序列 ,并选取脂鲤目、鲤形目和鲱形目鱼类作外类群 ,采用Bayesian方法和最大简约法 (MP)构建分子系统树。结果表明 :(1 )鲇形目鱼类细胞色素b基因序列中 ,与脂鲤目、鲤形目以及鲱形目鱼类相比存在 3bp的缺失 ;(2 )鲇形目鱼类各科代表种类形成一单系群 ;(3 )两种建树方法均支持科、粒鲇科和钝头科形成一单系群 ;而胡子鲇科、

ZnO nanostructures grown on AlN/sapphire substrates by MOCVD

ZnO nanorods and nanotubes are successful synthesized on AlN/sapphire substrates by metal-organic chemical vapour deposition (MOCVD). The different morphology and structure properties of ZnO nanorods and nanotubes are found to be allected by the AlN under-layer. The photoluminescence spectra show the optical properties of the ZnO nanorods and nanotubes, in which a blueshift of UV emission is observed and is attributed to the surface effect.

岩石磁组构可以揭示应变吗？——以华南地块早三叠世灰岩为例

一般认为磁组构能有效地反映岩石所经历的应变特征.为了研究不同类型的磁组构和不同期次应变之间的关系

单纵模布里渊掺铒光纤激光器的实验研究

提出了一种具有多环形腔(MRC)和光纤布拉格光栅可调谐滤波器(FBG-TF)相结合的单纵模布里渊掺铒光纤激光器(BEDFL)。实验中通过观察激光器输出光的拍频信号分析其光谱精细结构,分别讨论了布里渊增益、FBG-TF、MRC对BEDFL单模输出的贡献,给出了激光器的功率特性曲线和波长稳定性测试图。实验得到了在1550 nm处功率为4 dBm,信噪比(SNR)>60 dB,线宽小于1.5 kHz的稳定单纵模输出光。

应变异质结构中超薄中间层的应变协调作用

用一个简单模型讨论了应变异质结构中嵌人中间层对界面失配位错产生和应变释放的影响．根据能量最小原理得到了弹性能最小状态下界面失配位错密度，发现当中间层材料的晶格常数比衬底和外延层的都大或者都小并且厚度足够薄时，超薄中间层可以完全吸收支撑衬底和外延层之间的应变而不产生任何界面失配位错，具有所谓无支撑衬底的应变协调作用．