As one of the most important lumber grading systems in North America, machine grading does non-destructive test by stress rated machines, and then classify the lumbers into different grades according to their bending strength and the modulus of elasticity.

規(guī)格材的機(jī)械分等方法是北美一種很重要的分等體系国产精品久久婷婷人人爽，即采用機(jī)械應(yīng)力測(cè)定設(shè)備對(duì)木材進(jìn)行非破壞性試驗(yàn)最新国产福利黄色导航，按測(cè)定的木材彎曲強(qiáng)度和彈性模量確定木材的材質(zhì)等級(jí)国产二级三级精品。

First, the anatomical features, physical features and extraction contents of small-diameter lumbers were studied systematically and compared with mature wood. The reason that drying defects occurred easily in small-diameter lumber was discussed based on its properties.

首先国内精品一级无码免费播放费，測(cè)定了小徑木的解剖學(xué)特性人人干人操、物理特性和抽提物的含量把女人弄爽特黄a大片APP，并與成熟材進(jìn)行了比較，根據(jù)小徑木木材的上述性質(zhì)探討了小徑木鋸材產(chǎn)生干燥缺陷的原因日韩中文字幕在线92页。

The objective of this paper was to investigate the possibility of a transverse vibration technique for assessing static bending, tensile and compressive strength of structural lumbers.

共選擇了186根尺寸為38 mm 89 mm 3 658 mm的加拿大針葉樹(shù)商品材云杉-松-冷杉的建筑結(jié)構(gòu)材作為試驗(yàn)材料国产美女免费作爱视频99，探討采用一種橫向振動(dòng)技術(shù)來(lái)評(píng)估這些規(guī)格材的靜態(tài)抗彎、抗拉和抗壓強(qiáng)度的可行性久久9。

Third, drying defects and mechanical performance were determined, and the microstructure of the small-diameter lumber was observed with scan electron microscope. The drying quality of lumbers was assessed too.

第三国产黑丝足交视频，本試驗(yàn)對(duì)不同干燥方式下小徑木鋸材的可見(jiàn)干燥缺陷和力學(xué)性能進(jìn)行了測(cè)定，同時(shí)欧美一级一二三，采用掃描電鏡對(duì)干燥后小徑木鋸材的微觀結(jié)構(gòu)變化進(jìn)行了觀察黄色网站爱观赏，并對(duì)鋸材的干燥質(zhì)量進(jìn)行了評(píng)定。

The dependence between the flexural strength and the size of Chinese fir dimension lumber was investigated.206 dimension lumbers were sorted into three test groups in terms of dynamical modulus of elasticity.

選取206根人工林杉木規(guī)格材欧美狂野在线观看视频，按照動(dòng)態(tài)彈性模量配成3個(gè)測(cè)試組日韩不卡毛片午夜在线看片,，研究了規(guī)格材測(cè)試跨度與其抗彎強(qiáng)度之間的依存性，并利用斜率法和形狀參數(shù)法求得抗彎強(qiáng)度5%分位值和50%分位值的長(zhǎng)度尺寸效應(yīng)亚洲一级日毛免费观看。