Effect of the helix angle of router bits on chip formation and energy consumption during milling of solid wood

The effect of the helix angle of a router bit on chip formation and electric energy per volume (specific energy) under different feed speeds and cutting depths during the milling of maple and China fir by a computer numerically controlled (CNC) router was investigated. The peripheral cutting edge of router bits were custom-made at helix angles of 0°, 2°, 4°, 6°, and 8°. The feed speed varied from 600 to 4800mm/min, and the depths of cut were set at 1,2,3,4, and 6mm. The chips were classified by sieving into a flake type, a splinter type (5 and 10 mesh), a flow type (20 and 40 mesh), and a granule type (< 40 mesh). As the feed speed and the cutting depth increased for the five router bits, more chips of the flake type and the splinter type were produced. However, the number of granule-type chips under the larger helix angle was reduced. The energy per volume removed (specific energy) increased with the feed speed and the depth of cut while milling maple and China fir. More specific energy per cubic centimeter was consumed under the lower feed speeds and the smaller depth of cut. The specific energy can be expressed as a negative power function of the feed speed or the cutting depth for maple and China fir.     

激光干涉实时大角度测量方法研究

采用激光角度传感器镀膜技术及双光路系统,使激光干涉角度测量的测角范围达±100°,并具有实时、动态的特性.     

新型桥梁弹性伸缩缝

本文针对桥梁伸缩缝中存在的破损修复。提出了一种新型无缝桥梁弹性伸缩缝用于旧桥伸缩缝的改造，通过和板式橡胶伸缩缝、型钢缝的对比，证明该新型桥梁伸缩缝具有维修方便、行车平稳舒适、经济效益好等优点。     

连续式液压拼板机应用中的问题分析

介绍了连续式液压拼板机的基本结构,分析和讨论了拼板机在调节和应用中的几个主要问题熏并提出了几点改进建议。     

密度—直径关系研究中变量变换形式的选择和变量误差矩阵的估计

在林分自稀疏过程研究中，利用度量误差框匠形式估计林分断面积平均直径Ｄｇ 单位面积株数Ｎ关系框匠参数时，需要确定Ｄｇ和Ｎ的抽样误差ｅ、ε方差的比值。本文利用２０块人工落叶松标地的材料，经过再抽样，计算并比较了各种数据变换方式下，断面积平均直径与单位面积株数的方差比。     

木材声学-声波分等检测技术及工业应用

介绍了在应力波-超声波技术基础上发展起来的木材声学-超声波分等检测技术。通过测量超声波的传播速度以及一定时域内的传播能量，建立关系模型，对木材的抗弯弹性模量（MOE）和抗弯强度（σb）进行评估。该技术可在木结构建筑设计、木结构建筑现场调查、森林质量控制和管理等领域广泛应用。     

Dynamic properties of three types of wood-based composites

This study used a vibration test method to show that grain angles of face veneer have substantial effects on sound velocities and dynamic Youngs moduli of three types of wood-based composites. The sound velocity at 0° grain angle of face veneer was the highest, and it decreased with increasing grain angle in the range of 0° to 90°. This tendency was similar to that for dynamic Youngs modulus. The relationship between the grain angle of face veneer and the sound velocity of three types of wood-based composites can be expressed in the form of Hankinsons equation or a second-order parabolic equation. This study also showed that the application of orthotropic elasticity theory was valid for the three types of wood-based composites. The relationship between the grain angle of the face veneer and the Youngs modulus of three types of wood-based composites can be expressed in the form of the Jenkin equation, Hankinsons equation, or a second-order parabolic equation. Rule of mixture can also be used to predict the Youngs modulus of wood-based composite from the Youngs moduli of the two elements.Part of this study was presented at the 53rd Annual Meeting of the Japan Wood Research Society, Fukuoka, Japan, March 2003 and the 15th Annual Meeting of Chugoku Shikoku Branch of the Japan Wood Research Society, Higashi-Hiroshima, Japan, September 2003     

一种新型角规的研制

针对普通测树角规在森林调查中存在的弊端，研究发明了一种能自动改正坡度的新型角规，详细介绍了其原理、结构设计及使用方法。经实地测试，精度达97．3％。     

落叶松幼中龄林主要测树因子生长规律的研究

落叶松是一个分布广,易栽培,早期生长快的树种,因此,研究落叶松幼、中龄林主要测树因子的生长规律,对落叶松的早期管理有着很重要的指导意义。结果表明,落叶松幼、中龄林的主测树因子呈幂函数型生长曲线,其直径平均生长量多在0.4 cm以上,树高平均生长量均在0.4 m以上,而在20 a后,材积平均生长量高达0.002 m3。     

SEPARATING BROWN AND BLACK BEARS IN NORTHEAST CHINA USING TOOTH MEASUREMENTS

BearisveryvaIuableeconomicanimal.BearresourcereducedsharplywithMan'sexploitingandutilizingonnatufe,wbrseningofecologicalenvirorunent.Itisveryvaluabletoaccumulatebasicbiologicaldataofbcarre-searchinordertostudybcarpopulationecol-ogyindetail,providescientificbasisforbearresourcemanagement,thcnccdofarchacologr'andthestUdy'onthedataofnatUraldeathinfield.Toothisthemostdifficultdecomposedpall,sotheywillprovidcalotofinformationduringtheproccssofstudyonarchaeologyandnatllfaldeathindividual.Itisavery…