The variation of tree-ring widths of Scots pine (Pinus sylvestris L.) affected by air pollution

Using eight populations of Scots pine growing in foothills of the Sudetes (southern Poland) as an example, the character and causes of annual ring variation in 1900–1999 were studied. The climate had a short-term effect on radial growth during the whole period investigated. A long-term decrease of radial growth occurred after 1960, but only in some localities. It was probably caused by non-climatic factors, most likely by industrial pollution. The decline of trees during that period is mainly evidenced by a high variation of width of annual rings, a small similarity of chronologies of annual ring widths, and a lack of signal years. After 1990, the tree recovery process was evident. It was most intensive in localities where the earlier stress was the most severe. Then, trees started to produce wide annual rings, homogeneity of the growth reaction increased, and the signal years began to occur.     

构造柱施工质量的几项控制措施的一点体会

本文作者介绍了构造柱的设置、施工程序等 ,并且对其施工质量常出现的问题提出了几项控制措施。     

钻孔灌注桩施工事故预防及处理的几点体会

文章介绍了在砂砾土质钻孔塌孔的预防及处理方法，还介绍了首罐砼灌注及断桩处理方法。     

Pilot Study to Examine Radial Variation in Annual Ring Width, Density and Shrinkage

The annual ring width, density and shrinkage variation from pith to bark in Chinese fir (Cunninghamia lanceolata) and Boka sugi (Cryptomeria japonicd) were studied and compared. The results show that the ring width decreased sharply from pith to bark for Chinese fir. However, the ring width variation pattern for Boka sugi followed a different way, i.e., the ring width decreased to the fifth ring, increased to the tenth ring, decreased again to the fifteenth, and then increased to the twentieth, where it became constant. The large variations of Boka sugi appeared to show the maintenance of fast growth for many years. The annual ring mean density of Chinese fir increased gradually from pith to bark. However, the density changes for Boka sugi indicated the opposite trend, i.e., the mean density decreased gradually from pith to bark. The former showed a pattern as the same as a pine and a larch, and the latter was often found in a cedar and a cypress. The longitudinal shrinkage in juvenile wood was much hig     

Compressive failure of spruce wood rings reinforced with glass epoxy composite

We experimentally tested under radial compressive loads and statistically analyzed rings constructed from spruce wood and reinforced with glass fiber.We used the Weibull distribution in statistical analysis,and tested five types of rings including unreinforced and composite reinforced(CR) as wound around the ring,oriented as two layers at angles of 45°,60°,75° and 90° to the column axis.We calculated 95 % reliability of load carrying capacity of the rings by Weibull distribution.The highest load carrying capacity was obtained with CR rings at 60° to the axial axis of the ring.Load carrying capacities of rings at CR90,CR75,CR60 and CR45 were 137,192,215 and 126 %greater,respectively,than unreinforced rings.For unreinforced rings,failures resulted from catastrophic breaking of wood materials.None of the reinforced rings failed catastrophically because the outer surface of the rings was reinforced with glass–epoxy composite fiber.Cracks began at the core of the materials under the composite layer for all specimens and resulted in failure of the rings.     

拉枝、环割(剥)对干旱荒漠区富士苹果成花坐果的影响

【目的】研究拉枝、环割(剥)对干旱荒漠区富士苹果成花坐果的影响,为干旱荒漠区富士苹果促花促果技术的推广提供依据。【方法】以4年生富士苹果幼树为试材,采用拉枝+主枝环剥和拉枝+主枝、主干环割的方式促花促果。【结果】富士苹果幼树的树高较对照显著降低,冠径较对照显著减小,中心延长枝与主枝延长枝长度较对照显著缩短;1年生枝量分别是对照的1.99和2.59倍,短枝率分别比对照增加了20.87和23.42个百分点;单株成花率分别比对照增加了43.00和47.00个百分点,单株花芽量分别是对照的3.59和4.68倍,单株花序坐果率分别比对照增加了6.47和8.07个百分点;新梢叶片的叶长、叶宽及叶面积较对照显著减小,叶绿素SPAD值较对照显著降低。【结论】拉枝+主枝环剥和拉枝+主枝、主干环割处理既可控制富士苹果幼树的树冠大小,抑制新梢生长,增加枝量,促生短枝;又可提高单株、主枝以及长、中、短枝的花芽量、成花率、坐果率;还能抑制新梢叶片的生长和叶绿素的合成,其中以拉枝+主枝、主干环割处理的促花效果更好。     

桑树轮纹病病原菌的分离鉴定及其生物学特性研究

2012年6～8月,通过对桑树轮纹病病原菌分离、田间致病性测定、病原菌形态观察,将该病原菌鉴定为桑膝节霉,并对此病病原菌的生物学特性进行了研究。结果表明,不同培养基配方、温度、酸碱度、碳源、氮源、光照对桑树轮纹病病原菌菌丝的生长有一定影响,菌丝生长的最适宜培养基是理查培养基,最适温度是25℃,最适pH值是7.0,最适碳源为葡萄糖,最适氮源为蛋白胨,光照对菌丝生长无显著性差异,菌丝的致死温度和时间分别为85℃和10 min。对该病病原菌生物学特性研究为云南首次报道,对桑树轮纹病的防治具有一定的参考价值。     

国产三尖瓣成形环治疗功能性三尖瓣反流的近中期疗效观察

目的观察国产三尖瓣成形环在治疗功能性三尖瓣反流近中期的效果。方法 61例功能性三尖瓣反流患者分为De Vega成形术组（23例）和人工成形环组（38例）,比较两组术前及术后7 d、3个月、6个月、1 a三尖瓣反流面积、肺动脉收缩压、左心室射血分数、右心室内径、右心房内径和心功能。结果所有患者均治愈出院。两组术后各随访时点三尖瓣反流面积、肺动脉收缩压、左心室射血分数、右心室内径、右心房内径和心功能变化较术前明显改善,差异有统计学意义（P〈0.01）,中期上述指标人工成形环组要优于De Vega成形术组（P〈0.01或0.05）。结论三尖瓣成形术是治疗功能性三尖瓣反流的有效方法,人工成形环对术后功能性三尖瓣反流中期改善程度优于De Vega成形术。     

克氏原螯虾对几种人工洞穴的选择性

研究了在实验室内人工洞穴对克氏原螯虾存活率的影响 ,并在洞穴的质地、长度对入穴率的影响做了比较实验。研究结果表明 :有人工洞穴比自然状态下 ,螯虾的存活率提高了 6 4倍 ;螯虾更适应穴长较长的、避光、透气的人工洞穴