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51.
Thechemicalconstitutionsoftheextractivevaryquitindifferentfamily,genusandspecies.ThisVariancecanbeidentifvedmucheasierthanthevariancesofcollulose,semicolluloseand1ignin.Thusthestudyofchemicalconstitutionsofextractiveisanimportantbranchofphytochemistryandchemicalplanttaxonomy.TetracentronSinenseOliveisaspecialbroad-leavedspecies.Therearetracheidsbutnovessel.Bothcharactersofbroad-leavedandconiferspeciespresentinonespecies-Thusthestudyofchemicalconstitutionsoftheextractivefromthisspeciesisquite…  相似文献   
52.
The wood powder ofTetracentron Sinense Olive was extracted with the benzene and alcohol (2:1 v/v). Then, the extractive is analyzed in Gc and Gc-Ms. Twenty chemical constitutions of the extractive are separated and identified, which are as follows: calamenene; 2.6,10-trimethyldihexyl; 3-methoxybenzaldehyde; Methyl-4-methox-ybenzoate; 4-methoxyphenylacetone; 3.4-dimethoxybenzaldehyde; 3.4-dimethoxyhypnone; methyl-3.4-dimethoxybenzoate; Methyl-4-methoxyphenylacrylate; 4,4′-dimethoxycabonyl-diphenylethane; Methyl-3, 4,5-erimethoxybenzoate; Methyl-3.4-dimethoxyphenylacrylate; Methyl-myristate; Methyl-palmate; Methyl-zoomarate; Methyl-stearate; Methyl-oleate; Methyl-arachidate; Methyl-behenate; Dimethylazelate.  相似文献   
53.
Near-infrared (NIR) spectroscopy has been demonstrated as a means for rapid nondestructive determination of the chemical composition and final pulp yield of Eucalyptus camaldulensis in Thailand tree plantations. Multiple linear regression (MLR) analysis and partial least squares (PLS) analysis were introduced to develop statistical models in terms of calibration equations for total pulp yield, screened pulp yield, and contents of -cellulose, pentosans, and lignin in wood. In MLR analysis, a reasonably good calibration equation was found only for pentosans (standard error of prediction (SEP): 0.98%). The PLS analysis improved the accuracy of prediction for every criterion variable, especially for pentosans (SEP: 0.91%) and lignin (SEP: 0.52%). Also, in the case of screened pulp yield, we were able to use such a statistical result as an indicator of the characteristics of the pulp and paper. Thus, NIR spectroscopy could be satisfactorily used as an effective assessment technique for Eucalyptus camaldulensis plantation trees.  相似文献   
54.
肉桂油的成分研究   总被引:5,自引:0,他引:5  
肉桂油在世界上享有盛名,产量占世界总产量的80%。作者用GC/MS联用仪对我国广东、广西、福建三省(区)的肉桂叶油和肉桂皮油进行了定性与定量分析。鉴定出广东肉桂叶油13个组分;广东肉桂皮油11个组分;广西肉桂叶油14个组分;广西肉桂皮油12个组分;福建肉桂叶油12个组分,结果表明五种肉桂油的化学组成基本相同,均以反式肉桂醛为主要成分,其含量分别为81.0,84.1,54.6,73.2和73.6%。  相似文献   
55.
粉煤灰在江苏省公路施工中的应用   总被引:3,自引:1,他引:3  
本文分析了粉煤灰的化学组成、颗粒组成 ,介绍了粉煤灰在江苏省的应用情况 ,并对粉煤灰的应用进行了综合评价。  相似文献   
56.
Chemical changes in steam-pressed kenaf core binderless particleboard   总被引:4,自引:0,他引:4  
The effects of chemical changes in kenaf core binderless particleboards on the bonding performance and thickness swelling of boards were investigated by chemical and spectroscopic analyses. Mild steam-injection treatments (0.6–1.0MPa) caused significant degradation of hemicelluloses, lignin, and cellulose. Conventional hot pressing caused a lower degree of degradation of the chemical components. The hot-pressed kenaf core board without any binders showed poor bonding performance. Thus, it was found that partial degradation of the three major chemical components of the kenaf core by mild steam-injection treatment increased the bonding performance and dimensional stability of the binderless boards, and gave better quality binderless boards than those made by hot-pressing treatments.Part of this report was presented at the 4th International Wood Science Symposium, Serpong, Indonesia, September 2002; and at the 53rd Annual Meeting of The Japan Wood Research Society, Fukuoka, March 2003  相似文献   
57.
使用25%森泰水剂和5%森泰颗粒剂防除香椿幼林地的杂草研究试验结果表明:25%森泰水剂和5%森泰颗粒剂均能够有效防除香椿幼林地的五节芒、苦竹、刚竹、芒萁骨等多年生恶性杂草,防除效果均可达93%以上。使用25%森泰水剂除草比人工除草可减少用工56 1%~92 2%,降低除草成本36 1%~61%。同时,可根据幼林地杂草的种类、高度、盖度和水源等因素选择合适的森泰除草剂的剂型和剂量组合,以达到理想的防除杂草效果。  相似文献   
58.
应用10%草甘膦水剂、30%飞达可溶性粉剂、20%克无踪水剂3种化学除草剂在优质绿化苗木培育中进行对比试验,试验效果均较显著,其中30%飞达可溶性粉剂使用方便,成本较低,效果最好,可大面积推广。  相似文献   
59.
Softwood (Cryptomeria japonica) and hardwood (Fagus crenata) were treated in supercritical water (380°C, 100 MPa) for 8 s. The treated woods were fractionated to the water-soluble portion, methanol-soluble portion, and methanol-insoluble residues. For the methanol-soluble portion, which mainly consisted of lignin-derived products, gel permeation chromatography (GPC) and gas chromatographic-mass spectrometric (GC-MS) analyses were conducted to clarify the molecular weight distribution and to identify the monomeric products, respectively. GPC analysis revealed that the methanol-soluble portion contains monomeric and some oligomeric products. GC-MS analysis identified 19 guaiacyl compounds in the methanol-soluble portion from softwood, and 15 syringyl monomeric compounds in the methanol-soluble portion from hardwood. The structures of identified products included not only phenyl propane (C6—C3) units but also C6—C2 and C6—C1 units. In addition, the infrared spectra suggested that the methanol-soluble portion maintains the typical structure of lignin, although it is rich in condensed-type linkages with some changes in the propyl side chain. These results indicate that the supercritical water treatment cleaves not only ether linkages but also part of the propyl chains in lignin to give various aromatic compounds.  相似文献   
60.
The structural variety of the condensed tannins (proanthocyanidins) in the fruits of 16Diospyros species are reported. Eleven species contained condensed tannins mostly consisting of a mixture of catechin (CA) and gallocatechin (GCA) repeating units; the other five species did not. The GCA content in the CA-GCA total varied from 0.3% to 84.6%. The number of esterified gallic acid per one flavan repeating unit (degree of galloylation, DG) ranged from 0.01 to 0.89. The GCA content was found to be proportional to the DG values. Thus, 16Diospyros species tested may be classified into five groups by the analytical data of their condensed tannins. It may be interesting to compare their structural characteristics with those of the condensed tannins in other fruits, leaves, woods, and barks from the viewpoint of their biosynthesis and function in the plants.Part of this paper was presented at the 46th Annual Meeting of the Japan Wood Research Society, Tokyo, April 1995  相似文献   
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