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1.
粉煤灰陶粒混凝土配合比的正交实验研究   总被引:2,自引:1,他引:1  
针对大庆热电厂粉煤灰新型建材公司的粉煤灰陶粒,吉林省的鼎鹿牌水泥、大方牌减水剂,将水泥用量、净水用量、体积砂率和减水剂用量作为4个因素,每个因素取3个值,通过正交实验,测定试件的塌落度、7 d抗压强度、28 d抗压强度。实验结果分析,确定用以上材料可以配制强度为LC35级的轻骨料混凝土,其较佳配合比为C∶S∶G∶W∶减水剂=1∶1.60∶1.05∶0.34∶0.0065。此配合比下的新拌混凝土的塌落度为56 mm,7 d抗压强度均值33.2 MPa,28 d抗压强度均值40.1 MPa,标准差3.1 MPa。28 d抗压强度标准值为37 MPa。  相似文献   

2.
Wood is a highly sophisticated and multihierarchical material. The nanoscale structures in natural cell walls of red pine, American pine, and white ash specimens were investigated using the small-angle X-ray scattering (SAXS) technique. A tangent-by-tangent method was used to analyze the SAXS data. The results demonstrate that the multihierarchical scatterers in the three specimens can be divided into two dominant components, i.e., a sharp component and a wide component. The sharp component mainly corresponds to the contribution of cellulose microfibrils, and its size is almost unaffected by the water content. However, the wide component includes voids or microcracks and cellulose microfibril aggregates; its size changes, reflecting swelling and water accumulation in the voids or microcracks. Because of the different morphological features of the cell walls, softwood (red pine and American pine) displays different tendencies from hardwood (white ash) in terms of changes in the wide component with water content: the average scatterer size of the wide component has an incremental tendency with the water content in softwood, but it has a descending tendency in hardwood. Fractal analysis further revealed that in white ash the surface of scatterers is coarser and the scatterers form more compact nanostructures than in the two pine woods. All this nanostructural information can be used to explain well the difference of swelling behaviors between the two pines and the white ash.  相似文献   

3.
Xu YK  Liao SG  Na Z  Hu HB  Li Y  Luo HR 《Fitoterapia》2012,83(6):1120-1124
Bioassay-guided isolation of the stems of Gelsemium elegans has led to the isolation of two new Gelsemium alkaloids, 21-(2-oxopropyl)-koumine (1) and 11-methoxygelselegine (2), and two known alkaloids, koumine (3) and gelselegine (4). The structures of 1-2 were determined by spectroscopic (for both) and single-crystal X-ray diffraction (for 1) analysis. All compounds isolated were evaluated for their potential as immunosuppressive agents and the data suggested that Gelsemium alkaloids of different structural types possibly have potential as immunosuppressive agents.  相似文献   

4.
珍稀濒危植物夏蜡梅总生物碱含量分析   总被引:5,自引:1,他引:5  
对不同海拔高度、不同居群的夏蜡梅营养器官总生物碱含量进行测定,并分析了与环境因子之间的相关性。结果表明:①不同海拔高度夏蜡梅不同营养器官均含有生物碱,总生物碱含量以叶片最高,其余器官的含量均较低,叶片的总生物碱含量均显著高于其它营养器官,而其它营养器官之间差异均不显著。②阳坡的夏蜡梅叶片总生物碱含量显著高于阴坡,其余器官在阴、阳坡之间的含量差异不显著。③7个居群夏蜡梅叶片总生物碱含量存在较大差异,变化范围在1.468 1%~2.557 6%之间,平均为2.158 0%。④通径分析显示,土壤氮含量对夏蜡梅叶片总生物碱含量起正相关作用,土壤磷含量起负相关作用。而有机质、海拔、土壤pH值均可以间接通过土壤氮含量对叶片总生物碱含量起正相关作用。  相似文献   

5.
Samples of nine tropical hardwoods from Peru and sugar maple wood from Quebec were selected for moisture sorption and swelling tests at 25°C. These tests evaluated the fiber saturation point (FSP) by two methods: following adsorption over distilled water, and from the volumetric swelling intersection point. Cold-water and hot-water extractives, sequential cyclohexane, acetone and methanol extracts, ash content, wood density and interlocked grain were also determined on matched samples. The results indicated that adsorption tests over distilled water were not applicable for determining FSP in all wood species. Condensation of water vapor apparently occurred, even though temperature during adsorption was controlled to the nearest 0.01°C. The volumetric swelling intersection point method was judged more appropriate. FSP ranged from 15 to 25% for tropical hardwoods and was 30% for sugar maple wood. FSP was negatively correlated with wood density, acetone extracted fraction, interlocked grain and ash content. These parameters each exerted similar effects on variability in FSP.  相似文献   

6.
Abstract

Samples of nine tropical hardwoods from Peru and sugar maple wood from Quebec were selected for moisture sorption and swelling tests at 25°C. These tests evaluated the fiber saturation point (FSP) by two methods: following adsorption over distilled water, and from the volumetric swelling intersection point. Cold-water and hot-water extractives, sequential cyclohexane, acetone and methanol extracts, ash content, wood density and interlocked grain were also determined on matched samples. The results indicated that adsorption tests over distilled water were not applicable for determining FSP in all wood species. Condensation of water vapor apparently occurred, even though temperature during adsorption was controlled to the nearest 0.01°C. The volumetric swelling intersection point method was judged more appropriate. FSP ranged from 15 to 25% for tropical hardwoods and was 30% for sugar maple wood. FSP was negatively correlated with wood density, acetone extracted fraction, interlocked grain and ash content. These parameters each exerted similar effects on variability in FSP.  相似文献   

7.
The impact of trees on processes involved in soil acidification is not clearly understood. This study has measured the cation and anion composition of leaf litter from 28 tree species including both indigenous species and those exotic to Australia, which varied widely in composition. The excess cation content was calculated and shown to be highly correlated with ash alkalinity, determined by ashing and titration. Calcium (Ca) was the dominant cation in these samples and was highly correlated with ash alkalinity. Four rates of ground litter samples were incubated with an acid soil and after eight weeks soil pH and extractable cations were determined. The pH was strongly influenced by the addition of litter, and the increase in pH was linearly related to the amount of ash alkalinity added. Extractable Ca in the soil was highly correlated with Ca added in the litter. A second property of litter measured was the ability of water extracts from the material to complex aluminium (Al). This was assessed by reacting leaf litter extract with Al solution under standardised conditions and measuring the uncomplexed (monomeric) Al using the 8-hydroxyquinoline 15 sec reaction. Species varied markedly in complexing ability. Using the two properties, complexing ability and ash alkalinity, a framework is developed in which the effects of different species on nutrient cycling and podzolisation processes in relation to soil acidification are discussed, and predictions compared with available evidence from field studies. This index for assessing the potential impact of the removal/addition plant material could be used to predict the long- term consequences of cut and carry agroforestry systems on soil chemical properties. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

8.
Macleaya cordata (plume poppy) is a source of bioactive compounds, mainly isoquinoline alkaloids which are used in phytopreparations with anti-inflammatory and antimicrobial activities. In this study, the alkaloids sanguinarine, chelerythrine, their dihydro derivatives, protopine and allocryptopine and phenolics, gallic, protocatechuic, p-hydroxybenzoic, m-hydroxybenzoic, gentisic, p-coumaric, caffeic, ferulic and sinapic acids were determined in extracts prepared from M. cordata aerial part, seeds, and seed capsules using HPLC with UV detection and/or LC/MS with electrospray ionization. The highest content of sanguinarine and chelerythrine was found in capsules. Protopine and allocryptopine were major alkaloids in leaves including footstalks. The seed oil contained dihydrosanguinarine, dihydrochelerythrine and twelve fatty acids of which linoleic, oleic, palmitic and stearic acids predominated. In addition, sanguinarine reductase, a key enzyme in sanguinarine/dihydrosanguinarine equilibrium in plants, was found for the first time, in the soluble proteins of leaves. Finally, extracts were tested for antimicrobial activity using the microdilution method on standard reference bacterial strains.  相似文献   

9.
花椒精的加工技术研究   总被引:5,自引:0,他引:5  
开发研制以花椒为基料的改型及改性调味产品,改变其品种结构单一的商品格局,是发展花椒生产的需要,通过反复试验研究,用所提取的浓缩花椒调味物质原液,经调配、加工获得了新的改型调味品,即固体和液体花椒精,并确定了这两种产品的生产技术 。  相似文献   

10.
双稠哌啶类生物碱分子结构与杀线活性间关系   总被引:19,自引:2,他引:19  
赵博光 《林业科学》1998,34(5):61-68
使用培养基法和棉球法测定了苦豆碱、野靛碱、甲基野靛碱、苦参碱对松材线虫的杀线活性。两种生测方法测得的结果一致,表明苦豆碱的杀线活性最强,其log(1/ID50)(mol/棉球)=8.67,与文献中用同样方法测定的对松材线虫杀线活性的其它7种双稠哌啶类生物碱的杀线活性相比较,它也是最强。本文提出了双稠哌啶类生物碱对松材线虫的杀线活性强弱主要受其分子结构中官能团对的类型及其中的官能团的类型控制的假说。根据这一假说,推测了具高杀线活性的生物碱的分子结构。  相似文献   

11.
Fluorescein diacetate as a viability stain for tree roots and seeds   总被引:1,自引:0,他引:1  
Noland  Thomas L.  Mohammed  Gina H. 《New Forests》1997,14(3):221-232
Fluorescein diacetate (FDA) was tested as a viability stain for roots of green ash as well as for seeds of green ash and 10 other tree species. The viability level indicated by FDA staining of green ash roots agreed well with root growth potential results, bud condition assessment, and foliage browning measurements. In seed viability experiments, the FDA staining intensity of embryos was related to germination in 9 out of 11 species tested using a 30 minute stain incubation period. In the other 2 species, eastern hemlock and Scotch pine, embryo FDA staining intensity and germination were also similar, provided an 18 h stain incubation period was used. When two seedlots of differing viability were tested in each of white spruce, Douglas-fir, and pitch pine, significantly higher germination was reflected in significantly higher embryo FDA staining intensity. In Sitka spruce seed that was heat treated to produce a range of viabilities, the semilog plot of germination (log scale) and FDA staining intensity of the embryo (linear scale) had an r2= 0.95. Based on these preliminary results, FDA shows promise as a rapid viability stain for tree roots and seeds.  相似文献   

12.
Summary The lignin concentrations of the compound and cell corner middle lamella regions of the tracheid cell wall in radiata pine were determined relative to the S2 region using (i) interference microscopy and (ii) bromination in conjunction with energy dispersive X-ray microanalysis. Relative lignin concentration values for the cell corner middle lamella as determined by interference microscopy were 3.39 and 4.23 for the two specimens examined, while the corresponding values determined by bromination/EDXA using Br K X-rays were 1.95 and 1.21. Values for the compound middle lamella were 1.54 and 0.86 as determined by bromination/EDXA. Possible reasons for the poor agreement between the two techniques are discussed.  相似文献   

13.
The objective of this study was to evaluate influence of steam treatment on surface quality and hardness of eastern redcedar (Juniperus virginiana L.). Defect-free samples with dimensions of 40 mm by 50 mm in by 20 mm were used for the tests. Specimens were exposed to steam having a temperature of 130 °C for 1-h and 3-h periods of time. Surface roughness of the samples at initial and exposed conditions was determined using stylus type equipment across the grain orientation on tangential surface of each sample. Janka hardness of the control and treated samples was also determined on Comten testing system. Based on the findings in this work, no significance was found between surface roughness values of the specimens steamed for 1 and 3 h. However, both types of steamed specimens had higher average roughness values ranging from 52 and 60 % than those of control samples. It appears that 3-h steaming adversely influenced hardness of the samples reducing its 9 % as compared to those of control samples. Densification effect of steaming on the samples was also evaluated using scanning electron microscope (SEM) and it was determined that steaming had some crushing effect on the cell wall.  相似文献   

14.
粉煤灰在信南高速公路施工中的应用分析   总被引:1,自引:0,他引:1  
结合信南高速公路第十二合同段底基层施工情况,试验确定粉煤灰、天然砂及水泥等材料的技术指标,对配合比设计和施工后路用性能进行分析,并结合材料特点介绍水泥粉煤灰稳定砂施工的注意事项,为进一步研究水泥粉煤灰稳定砂作为底基层填筑材料提供实践经验。  相似文献   

15.
本文以辽宁省长白落叶松栽培区的22个市、县为样本,利用8个气候因子,应用主分量分析法(PCA)进行计算。结果表明,前两个主分量信息占有率达全部信息的8471%,取前两个主分量对样本进行了二维排序。根据排序结果对栽培区进行了气候区划,划分了长白落叶松生长适宜区、较适宜区和可生长区三个区域,分析了各区与长白落叶松生长相关的气候条件,为确定该树种在不同地区的栽培措施和经营方向提供了气候依据。  相似文献   

16.
Abstract

The moisture sorption and swelling of spruce specimens impregnated with linseed oil and unimpregnated controls were studied in two sorption experiments: from 0 to 55% relative humidity (RH) and from 55% RH to water saturation. Sorption isotherms were also determined using a sorption balance. The impregnated specimens had lower rates of both moisture sorption and swelling than the unimpregnated controls; however, there was no significant difference in final moisture contents. In addition, the linseed oil impregnation did not improve the dimensional stability of the wood; in most cases the specimens impregnated with linseed oil swelled more than the unimpregnated controls. For the impregnated specimens, reductions in swelling rates were in most cases seen without corresponding reductions in final swelling. The moisture sorption rate was reduced for the impregnated specimens but there were generally no reductions in equilibrium moisture content.  相似文献   

17.
Granulated wood ash has been proposed as a slow release fertiliser suitable for forest soils. In this study ectomycorrhizal colonisation of roots and ash granules was studied in a 40-year-old spruce forest treated with 0, 3 or 6 t ha−1 granulated wood ash. We used PCR-RFLP methods for ITS-typing and identification of ectomycorrhizal fungi. In total 20 different ITS-types were recognised on roots in the organic soil horizon. Five of these were identified to species and two to genus. Six species, Tylospora fibrillosa Donk, Cortinarius sp. 3, Piloderma sp. 1, and three unidentified ITS-types (Ve-95-1, Tö-95-3 and Ve-95-9) each occurred on over 5% of the total root tips analysed. Together these comprised 55% of the ectomycorrhizal community on the screened roots.

Ash granules collected from the fertilised plots were normally colonised by fungal mycelia. PCR-RFLP analysis of these mycelia revealed the presence of four ITS-types. Three of these (Piloderma sp. 1, Ha-96-3 and Tor-97-1) were also present on the mycorrhizal roots. Piloderma sp. 1 was the most abundant species colonising roots. A possible role of ectomycorrhizal mycelia in the direct mobilisation of nutrients from ash granules is discussed.  相似文献   


18.
Saglam H  Arar G 《Fitoterapia》2003,74(1-2):127-129
The quality control determinations on herba and radix Chelidonii prepared from Chelidonium majus L., growing wildly in Bursa, Uluda? surroundings, have been conducted according to DAB 9. Ash, humidity and total alkaloidal content have been carried out. LC(50) value of chelidonine and protopine, the most important alkaloids, and the alcoholic and water extracts of herba Chelidonii were determined using brine shrimp (Artemia salina) lethality bioassay.  相似文献   

19.
Charcoal was produced from short rotation tropical species ofLeucaena leucocephala andTectona grandis. The combustion-related properties, moisture content, specific gravity and percentage element composition of carbon, hydrogen, oxygen, nitrogen, sulphur and ash in wood and charcoal from the two species were determined. The gross heat of combustion of wood and charcoal was also determined.There were significant differences in the moisture content, specific gravity and percentage element composition between wood and charcoal from the two species. The carbon and ash content of charcoal were higher than those of wood. The average heat of combustion of charcoal 25.25 MJKg–1 was higher than that of wood 13.75 MJKg–1.  相似文献   

20.
Vibrational properties and fine structural properties of wood were measured at high temperatures. Sitka spruce (Picea sitchensis Carr.) and Shioji (Japanese ash, Fraxinus spaethiana Lingelsh.) were used as specimens. The specimens, the system to support them, a magnetic driver, and a deflection sensor were in an electric drying oven, where vibration tests were conducted. The heating temperatures ranged from room temperature to 200 °C in 25 °C increments in both heating and cooling processes. X-ray diffractometry was carried out using positive sensitive proportional counter (PSPC) at room temperature to 200 °C in 20 °C increments in both heating and cooling processes. Received 13 December 1999  相似文献   

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