美汉草（Meehania fargesii Levl）生物量分配分析

调查阔叶红松林林下早春开花植物美汉草(Meehania fargesii Levl)各个器官生物量分配变化情况.结果表明:在整个生长季节中,美汉草各器官生物量总体上呈现先增加后减少的趋势,5月初~7月初,根生长速率先快后慢,茎叶生长速率先慢后快,7月中旬以后各器官生物量逐渐减少;美汉草有性生殖的生殖分配占总生物量的比例较小(4%~6%);根冠比在5~6月不断上升,6~7月迅速下降,7月以后保持稳定;根和茎叶生物量分别与总生物量呈显著的线性正相关关系.分析显示:为了适应阔叶红松林林下的光照变化,在林分郁闭前,能量主要分配给地下部分;林分郁闭后,茎叶生长占主导.美汉草主要以营养繁殖为主,第2年的地下根状茎来自第1年地上茎的繁殖方式及生物量分配策略,可能是美汉草成为林下优势草本的重要原因.     

《特种建筑材料》双语教学的探索与实践

就《特种建筑材料》采用双语教学的教材、课件、教学形式、作业、考试等问题进行了探讨,并对《特种建筑材料》开展双语教学一年多来的成效进行了分析,希望对其他课程的双语教学开设有一定借鉴作用。     

论减灾系统的远程公平化

远程公平化是偏向于远程的公平，旨在寻求系统整体的优化。在一定的约束条件下，通过域的分隔、变形，中心的定位与相应的远程运作机制，可消减不利因素对系统的干扰，扩大结构瓶颈，调优技术性弱点、难点、远点、易忽视点的指标期望与实现值，抑小扬大，隐近就远，弥补系统缺陷，或于不完备的条件下构建 完备系统，保障全局利益与远效，推进减灾管理的科学化，改善各个方面的减灾工作。     

H型钢多道次粗轧工艺过程的数值分析

为了分析现有型钢轧制工艺的合理性,必须综合考虑轧件的微观组织演化、轧制力等多方面因素.为此,文中提出了针对H型钢多道次轧制过程的综合数值分析流程,通过热模拟实验和金相观测,建立轧件材料的高温屈服应力模型及奥氏体再结晶预报模型,并构建基于网格重构的多道次仿真分析方法.对某11道次H型钢多道次粗轧过程的仿真计算表明:轧制力的计算结果和现场实测数据吻合较好,现有多道次粗轧工艺对轧件腹板的晶粒细化作用较为明显.     

PORLES: A parallel object-relational database system

We developed a parallel object-relational DBMS named PORLES. It uses BSP model as its parallel computing model, and monoid calculus as its basis of data model. In this paper, we introduce its data model, parallel query optimization, transaction processing system and parallel access method in detail.     

Effects of AlN on the densification and mechanical properties of pressureless-sintered SiC ceramics

In the present work, Si C ceramics was fabricated with Al N using B_4 C and C as sintering aids by a solid-state pressureless-sintered method. The effects of Al N contents on the densification, mechanical properties, phase compositions, and microstructure evolutions of as-obtained Si C ceramics were thoroughly investigated. Al N was found to promote further densification of the Si C ceramics due to its evaporation over 1800 °C,transportation, and solidification in the pores resulted from Si C grain coarsening. The highest relative density of 99.65% was achieved for Si C sample with 15.0 wt% Al N by the pressureless-sintered method at 2130 °C for 1 h in Ar atmosphere. Furthermore, the fracture mechanism for Si C ceramics containing Al N tended to transfer from single transgranular fracture mode to both transgranular fracture and intergranular fracture modes when the sample with 30.0 wt% Al N sintered at 1900 °C for 1 h in Ar. Also, Si C ceramics with 30.0 wt% Al N exhibited the highest fracture toughness of 5.23 MPa m~(1/2) when sintered at 1900 °C.     

可持续城市化评估——安徽5座城市实证研究

近年来,城市化发展日益受到重视,如何衡量城市化的可持续性成为亟需解答的问题.本文以安徽省黄山、池州、安庆、铜陵、芜湖5市为例,构建了城市可持续性发展指标体系,采用熵值法,利用MATLAB软件,得出城市可持续性指数.引入经济学弹性模型,得到可持续城市化弹性系数.结果表明:经济可持续性指数最高的是芜湖,安庆、铜陵处于同一水平,黄山、池州处于同一水平;芜湖社会可持续性指数最高但呈下降趋势;黄山、池州环境可持续性指数处于较高水平,铜陵环境可持续性指数大幅下降;除池州、铜陵外,其他三个城市都是可持续的城市化.生态环境对城市的持续性有重要的影响,城市的主导产业、行政区划调整、人口数量的增加等也会对其产生影响.     

TPP1 is a homologue of ciliate TEBP-beta and interacts with POT1 to recruit telomerase

Telomere dysfunction may result in chromosomal abnormalities, DNA damage responses, and even cancer. Early studies in lower organisms have helped to establish the crucial role of telomerase and telomeric proteins in maintaining telomere length and protecting telomere ends. In Oxytricha nova, telomere G-overhangs are protected by the TEBP-alpha/beta heterodimer. Human telomeres contain duplex telomeric repeats with 3' single-stranded G-overhangs, and may fold into a t-loop structure that helps to shield them from being recognized as DNA breaks. Additionally, the TEBP-alpha homologue, POT1, which binds telomeric single-stranded DNA (ssDNA), associates with multiple telomeric proteins (for example, TPP1, TIN2, TRF1, TRF2 and RAP1) to form the six-protein telosome/shelterin and other subcomplexes. These telomeric protein complexes in turn interact with diverse pathways to form the telomere interactome for telomere maintenance. However, the mechanisms by which the POT1-containing telosome communicates with telomerase to regulate telomeres remain to be elucidated. Here we demonstrate that TPP1 is a putative mammalian homologue of TEBP-beta and contains a predicted amino-terminal oligonucleotide/oligosaccharide binding (OB) fold. TPP1-POT1 association enhanced POT1 affinity for telomeric ssDNA. In addition, the TPP1 OB fold, as well as POT1-TPP1 binding, seemed critical for POT1-mediated telomere-length control and telomere-end protection in human cells. Disruption of POT1-TPP1 interaction by dominant negative TPP1 expression or RNA interference (RNAi) resulted in telomere-length alteration and DNA damage responses. Furthermore, we offer evidence that TPP1 associates with the telomerase in a TPP1-OB-fold-dependent manner, providing a physical link between telomerase and the telosome/shelterin complex. Our findings highlight the critical role of TPP1 in telomere maintenance, and support a yin-yang model in which TPP1 and POT1 function as a unit to protect human telomeres, by both positively and negatively regulating telomerase access to telomere DNA.     

河北省御道口牧场气候生产潜力估算

御道口牧场位于河北省围场县北部坝上地区,是河北省畜牧业生产的重要产区.根据牧场多年降水和气温等气象观测资料,同时考虑地形因素和最小面积的限制,对御道口牧场的气候生产潜力进行了估算.得出牧场的气候生产潜力在3.75～5 t·hm-2·a-1之间,牧场内适合发展人工草地的平地和缓坡(＜5°)约占总土地面积的76.5%.     

２００３年SARS对中国交通客运量影响的后评价研究 ———基于本底趋势线全国２８个省（市）自治区的分析与估算

２００３年SARS是中国公众健康的“灾难”,交通旅客运输因此蒙受巨大损失。依据本底趋势线理论, 对此次危机的交通客运量损失进行了定量估算。结果显示：２００３年SARS共造成交通旅客损失１０畅０７亿人次,其 中,公路损失８畅８８亿人次,铁路损失１畅０５亿人次,航空损失１６１１畅７万人次,水运损失１９４３万人次;危机的生命 周期从２００３年４月开始,５～６月全面爆发,７～８月消减衰退,１１～１２月有一定的补偿;由于交通区位和SARS 疫情的差异,全国２８个省（市）自治区客运量损失可划分为４个等级,其中,广东、