关于颗粒悬浮机理和悬浮功的讨论

从分析气体分子的悬浮和静水中Ｂｒｏｗｎ微粒的悬浮之机理出发，论述了重力场中粒子（分子、微粒等）的悬浮不一定需要其它外力，粒子本射的任何形式的无规则运动，达到一定强度后都能使粒子弥散悬浮。河流中的泥沙颗粒和气（水）力输送管道中的颗粒的悬浮也主要靠颗粒物的无规则运动，作用于颗粒的升力和其它力可改变颗粒悬浮沿高度的分布，但仅用这些力９若无任何无规则运动）无法解释颗粒的弥散悬浮状态。讨论了颗粒对流动阻力的…

Collective evolution characteristics and computer simulation of short fatigue cracks

Fatigue testing was conducted using a kind of triangular isostress specimen to obtain the short-fatigue-crack behaviour of a weld low-carbon steel. The experimental results show that short cracks continuously initiate at slip bands within ferrite grain domains and the crack number per unit area gradually increases with increasing number of fatigue cycles. The dispersed short cracks possess an orientation preference, which is associated with the crystalline orientation of the relevant slip system. Based on the observed collective characteristics, computer modelling was carried out to simulate the evolution process of initiation, propagation and coalescence of short cracks. The simulation provides progressive displays which imitate the appearance of experimental observations. The results of simulation indicate that the crack path possesses a stable value of fractal dimension whereas the critical value of percolation covers a wide datum band, suggesting that the collective evolution process of short cracks is sensitive to the pattern of crack site distribution.

不同放牧率对不同草原主要植物叶片解剖结构和化学成分的影响

本文选取不同放牧率下的优势植物为研究对象，主要从植物解剖结构和化学成分方面，对内蒙古典型草原和北美混合普列里草原的放牧演替机制进行探讨，这将有助于进一步揭示放牧演替过程及其主要植物对放牧的适应机理。具体研究结果如下： 1. 长期不同放牧率的放牧（内蒙古典型草原区放牧15年和混合普列里草原放牧19年）对所有物种（IMGERS的羊草（Leymus chinensis）、冰草（Agropyron cristatum）、糙隐子草（Cleistogenes squarrosa）、扁蓿豆（Melissitus rutenica）、小叶锦鸡儿（Caragana microphylla）、冷蒿（Artemisia frigida）和星毛委陵菜（Potentilla acaulis）和CGREC的Artemisia frgida ，Poa pratensis， Agropyron smithii，Solidago rigida， Helianthus rigidus和Symphoricarpos occidentalis）叶片的角质层厚度、表皮细胞面积、叶肉细胞面积、栅栏/海绵组织厚度、叶片厚度、中脉厚度均产生显著影响;放牧显著影响了两个研究区不同生活型功能群植物叶片的角质层厚度、表皮细胞面积、叶肉面积、栅栏/海绵组织和中脉厚度。内蒙古典型草原研究区草本植物功能群的叶片下角质层厚度、栅栏/海绵组织厚度显著大于灌木功能群，而美国混合普列里草原研究区，草本植物功能群的叶片下角质层厚度、表皮细胞面积、叶肉细胞面积、栅栏/海绵组织厚度、叶片厚度、中脉厚度均显著大于灌木功能群。 2. 内蒙古典型草原研究区放牧率显著影响了糙隐子草和小叶锦鸡儿的比叶面积（SLA）;在美国混合普列里草原研究区，放牧率显著影响了冷蒿SLA。但对生活型功能群的SLA影响不显著。 3. 内蒙古典型草原研究区放牧对物种叶片叶绿素含量、纤维素含量影响显著，放牧仅显著增加了扁蓿豆叶片的含氮量。美国混合普列里草原研究区物种叶片的全碳、干物质、酸性洗涤纤维、叶绿素a+b含量受放牧率的显著影响。两研究区放牧率对叶片叶绿素a+b含量影响显著。放牧率也显著影响了不同生活型功能群的全碳含量和叶绿素a+b含量。 4. 两研究区叶片表皮细胞面积和叶肉细胞面积无牧和重牧下显著正相关，表皮细胞面积和叶片厚度在轻牧下显著正相关，叶肉细胞面积和叶片厚度在无牧、中牧和重牧下显著正相关，比叶面积和叶绿素a+b含量在轻牧下显著正相关。扁蓿豆叶片的表皮细胞面积和叶肉细胞面积间存在显著的正相关，其全碳含量和叶绿素a+b含量间存在显著的正相关;Artemisia frgida叶片的角质层厚度和叶片厚度间显著正相关，Poa pratensis叶片的角质层厚度和表皮细胞面积间显著负相关，Solidago rigida叶片表皮细胞面积和光合速率显著正相关。Helianthus rigidus叶片叶肉细胞面积和叶片厚度显著负相关。

An antimicrobial peptide with antimicrobial activity against Helicobacter pylori

An antimicrobial peptide named odorranain-HP was identified from skin secretions of the diskless odorous frog, Odorrana grahami. It is composed of 23 amino acids with an amino acid sequence of GLLRASSVWGRKYYVDLAGCAKA. By BLAST search, odorranain-HP had si

云南马关矮马和普通马血清蛋白多态性与类缘关系的研究

云南马关矮马和普通马血清蛋白多态性与类缘关系的研究云南省畜牧兽医科学研究所解德文中科院昆明动物研究所刘爱华，林世英蛋白质多态性的研究是指从分子水平阐明群体中基因频率变化的有效手段，能较客观地反映不同品种马的遗传差异￣［１］。本文采用淀粉凝胶电泳技术测...

THz-field-induced electronic transmission step-structure for a quantum wire

We study theoretically the low-temperature electronic transport property of a straight quantum wire under the irradiation of a finite-range transversely polarized external terahertz (THz) electromagnetic (EM) field. Using the free-electron model and the scattering matrix approach, we show an unusual behaviour of the electronic transmission of this system. A sharp step-structure appears in the electronic transmission probability as the EM field strength increases to a threshold value when a coherent EM field is applied. We demonstrate that this effect physically comes from the inelastic scattering of electrons with lateral photons through intersubband transitions.

两种线程池的实现和性能评价

线程池被广泛地应用在中间件如Web应用服务器、事务监控器等的实现中。实现线程池的方法主要有半同步/半异步(Half-Sync/Half-Asyn)模式和领导者/跟随者(Leader/Follower)模式。实现了这两种线程池,从理论上分析了它们的性能,并进行了性能实验。实验数据表明Leader/Follower模式具有较高的性能优势。