小型饲料搅拌机和平模颗粒机组合使用制备颗粒饲料的工艺研究

[目的] 研究JB-300型精饲料搅拌机和300型平模颗粒机组合使用制备牛羊精补料颗粒饲料的最佳工艺参数。[方法] 测定不同搅拌时间、装载系数对饲料混合均匀度的影响;确定搅拌混合工艺参数的基础上,测定不同玉米粉碎粒度、水分含量对颗粒饲料成型率的影响。以模孔直径、玉米粉碎粒度和水分含量为测定因素,以成型率和硬度的综合加权评分值为指标,确定制备颗粒饲料的最优组合参数。[结果] 搅拌时间为10 min、20 min的变异系数均显著（P<0.05）低于搅拌5 min和15 min。装载系数为80%时,变异系数显著（P<0.05）低于装载系数为70%和60%。玉米粉碎粒度为2 mm和4 mm时,颗粒饲料成型率显著（P<0.05）高于玉米粉碎粒度为6 mm和8 mm。水分含量为10%和13%时,颗粒饲料成型率显著（P<0.05）高于水分含量为16%和19%。影响正交试验综合加权平均分值的模孔直径、玉米粉碎粒度、水分含量的极差分别为18.76、1.64和3.47。[结论] JB—300型精饲料搅拌机混合饲料最佳参数：装载系数为80%、搅拌时间为10 min;300型平模颗粒机制作精补料颗粒饲料最佳参数：模孔直径为4 mm（压缩比为6）、玉米粉碎粒度为4 mm、水分含量为13%。     

我国南方湿地松木材物理力学性质变异初探

我国南方五省区湿地松木材的密度、晚材率和各项力学强度,随纬度的增加,呈递减状态。纬度与气干容重之间的直线回归方程为:G=1.28—0.027L,相关系数r=0.984.产生此现象的主要原因是,木材的管胞宽度和厚度随着纬度的增加逐渐变窄、变薄。产地的年平均气温和年降水量对湿地松树木的年轮宽度和晚材带宽度影响较大;年轮和晚材带的平均宽度随产地自北向南依次增加,随着山地海拔的升高而减小。     

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.     

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。