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921.
922.
用电阻应变法测定木材顺纹抗压弹性常数的研究 总被引:9,自引:1,他引:9
用电阻应变法测定木材顺纹抗压弹性常数的研究龚蒙(南京林业大学南京210037)关键词木材,电阻应变法,弹性模量,柔量木材弹性常数是反映木材刚性的指标,也是木结构设计和木质复合材料设计的重要参数。电阻应变法(简称电测法)在木材科学中的应用是最近二、三十... 相似文献
923.
The development time, longevity, and fecundity of Dysaphis plantaginea were measured on six apple cultivars (Golden delicious, Red delicious, Renetta canada, Florina querina, Golden lasa, and Golden orange) under controlled conditions, in order to establish the life tables of D. plantaginea on the different cultivars and to evaluate the tolerance of the cultivars against this pest. The intrinsic rates of increase (r
m) were 0.07 and 0.11 day−1 on F. querina and G. orange, respectively. On the other four cultivars, rates ranged between 0.22 and 0.26 day−1, with the maximum value registered on G. lasa. All the biological and demographic parameters evaluated, i.e. survival of larvae (M = 5.8–72.2%), mean generation time (T = 14.94–20.62 days), and net reproduction rate (R
0
= 4.23–47.37), show that G. orange and F. querina are tolerant cultivars while R. delicious, R. canada, G. lasa, and G. delicious are susceptible hosts. 相似文献
924.
Effects of phosphoric acid on liquefaction of wood in phenol and optimum liquefaction processing parameters 总被引:6,自引:0,他引:6
ZhangQiuhui ZhaoGuangjie JieShujun 《中国林学(英文版)》2004,6(3):50-54
To clarify the influencing factors of liquefaction of wood in phenol using phosphoric acid as a catalyst and get its liquefaction technology, a study on the liquefaction technology of Chinese fir (Cunninghamia lanceolata) and poplar (triploid Populus tomentosa Carr) under different conditions was conducted. The results indicate that the residue rate decreases with the increase of liquefaction temperature, liquefaction time, catalyst content or liquid ratio. It is also found that the optimum condition of liquefaction for poplar is estimated as: the reaction temperature of 180 ℃, the reaction time of 2.5 h, liquid ratio (phenol/wood ratio)of 4.5 and catalyst content of 8%, and 4.2% residue rate could be obtained. Under the processing parameters of temperature 180 ℃, the reaction time of 2.5 h, liquid ratio (phenol/wood ratio) of 4 and catalyst content of 10%, the residue rate of Chinese fir can reach 5.6%. 相似文献
925.
纤维的加入会影响沥青的路用性能,同时又对混合料有着加筋与阻裂的作用。研究表明,纤维在混合料中的质量百分比以及纤维的分散特性均对纤维沥青混合料有着明显影响。苯文通过对加入不同纤维用量沥青混合料的马歇尔实验,研究沥青混合料马歇尔实验指标的变化,特别是最佳沥青用量和密度,同时分析其产生变化的原因,为指导纤维混合料设计和施工提供依据。 相似文献
926.
谭一凡 《中南林业科技大学学报(自然科学版)》1996,(2)
对3个油橄榄品种(Chetoui,Picholinemarocaine和Oliviera)开花生物学的研究表明:在盛花期后的第二至第六周间有一幼果脱落高峰,该高峰与幼果从初生长高峰相吻合.这证实的果的大量脱落与果实间的竞争有关.统计结果显示:盛花期各个品种单位花序之结果数相差很大,但收获时这一参数却趋于同一;相反,收获时各品种结实花序的留存率却相差甚大,这说明品种间结实能力差异极大.控制授粉试验表现:品种Chetoui具有一定程度的自花不孕性. 相似文献
927.
928.
A method of optimizing planar transformers' design based on integrated software platform iSIGHT is presented.Through integrating the circuit simulation tool Saber and Maxwell 3D to the optimization tool iSIGHT,the parasitic effects on planar transformers are studied carefully.Changing the thickness of the insulator layer between the primary and the secondary can obtain different values of parasitic parameters and a new method to avoid parasitic oscillations with dangerous high voltage spikes to improve the SMPS performance is established.Hence an optimal design of planar transformer is obtained.The final optimal simulation analysis results verify the correctness of above theoretical study. 相似文献
929.
Liu Chengquan Wen Liangying Chen Min 《保鲜与加工》1997,(1):98-103
In the paper,the relationship between the structure parameters and P V characteristics and recirculation ratio of the burner are studied by the simulated experiment of a self recirculation burner.The optimum structure parameters of the burner are analysed and tested in the cases that the produced recirculation amaunt of optimal controlled NO x consumpting the lowest energy can be ensured. 相似文献
930.
A new good idea named Electro-hydraulic Impulse is described in the paper. Electro-hydraulic impulse is a process which integrates strong electrical field, strong magnetic field, ultrasonic wave, radiation of light and cavitation. With it, a kind of water named strongly polar activated water is generated. Using strongly polar activated water to make concrete blocks, the mechanical performance of concrete can be improved greatly. With the proper parameters, the compression strength of concrete can be increased by 48% percent. This has been proved by some experiments. 相似文献