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1.
In this paper, factor analysis is introduced to evaluate the flammability of 55 foliage species that may be used in China for construction of the fuel break network of forest strips with lower flammability. Six pyric parameters, i.e. air dry moisture content, absolute dry moisture content, ignition point, ash content, caloric value and extractive content, are measured and used as variables for factor analysis. The covariance analysis shows that four principal factors can be extracted to reflect the flammability in different physical and chemical senses. In terms of the contributions of the four factors to the variances and the physical significance of the relevant parameters, the four factors are, respectively, termed as ‘flaming factor,’ ‘air dry factor,’ ‘ash factor’ and ‘absolute dry factor.’ The stability of the factor analysis method is examined by a different number of samples considered, and the variation degrees of the orderings indicate that the method has high reliability to measure the total flammability of foliage species. The results of the flammability evaluation are verified by comparison with the recommended tree species in the Chinese technology standard. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   
2.
Several published foliage mass and crown radius regression models were tested on the preparation of the input for the reflectance model of Kuusk and Nilson [Kuusk, A. and Nilson, T. (2000), A directional multispectral forest reflectance model. Remote Sensing of Environment, 72(2):244–252.] for 246 forest growth sample plots in Estonia. In each test, foliage mass and crown radius for trees in the sample plots were predicted with a particular pair of allometric regression models. The forest reflectance model was then run using the estimated foliage mass and crown radius values. Reflectance factors were simulated and compared with the reflectance values obtained from three atmospherically corrected Landsat 7 Enhanced Thematic Mapper (ETM+) scenes. The statistics of linear regression between the simulated and measured reflectance factors were used to assess the performance of foliage and crown radius models. The hypothesis was that the best allometric regression models should provide the best fit in reflectance. The strongest correlation between the simulated and measured reflectance factors was found in the short-wave infrared band (ETM + 5) for all the images. The highest R2 = 0.71 was observed in Picea abies dominated stands. No excellent combination of foliage mass and crown radius functions was found, but the ranking based on determination coefficients showed that some linear crown radius models are not applicable to our data. Processing of raster images, reflectance measurement for small sample plots, usage of tree-species-specific fixed parameters (specific leaf area, etc.), and the ignored influence of phenology introduced additional variation into the relationships between simulated and measured reflectance factors. Further studies are needed, but these preliminary results demonstrate that the proposed method could serve as an effective way of testing the performance of foliage mass and canopy cover regressions.  相似文献   
3.
BACKGROUND: The behavior of cadmium in ecosystems needs to be monitored because of the human toxicity of this heavy metal. The need recently arose for a simple and quick on‐site test for trace levels of Cd in food and environmental samples. In response, an immunochromatographic assay kit for detecting Cd was manufactured by Kansai Electric Power Co. of Japan. This kit uses the antigen–antibody complex reaction between the Cd–EDTA complex and an anti‐Cd–EDTA antibody and shows the results in terms of the degree of color developed on a test paper. We previously reported the successful use of this kit to determine Cd concentrations in brown rice. Here, we applied the kit to the determination of Cd concentrations in rice foliage and soil. RESULTS: Cadmium in rice foliage was not extracted successfully by the method used for brown rice. However, it was successfully extracted by 0.1 mol L?1 HCl solution at a rice foliage:HCl ratio of 1:20, and coexisting metals were removed sufficiently by the column treatment. The Cd concentrations determined by immunochromatographic assay were well correlated with the values obtained by acid decomposition and inductively coupled plasma mass spectrometry. The 0.1 mol L?1 HCl‐extractable Cd concentration in soil was also determined successfully with the kit. CONCLUSION: Approximate Cd concentrations in rice plants and 0.1 mol L?1 HCl‐extractable Cd concentrations in soil can be monitored easily and quickly by this method at locations where facilities for acid digestion and precision analysis are not available. Copyright © 2009 Society of Chemical Industry  相似文献   
4.
《分离科学与技术》2012,47(6):829-837
The present paper deals with the fermentation of chopped, dried, woolly foxglove foliage, the extraction of secondary glycosides from fermented woolly foxglove foliage by the percolation method and the isolation and purification of digoxin. Optimal process conditions for fermenting the chopped, dried, woolly foxglove foliage, extracting of digoxin from the fermented woolly foxglove foliage by percolation, and further isolating and purifying of digoxin were defined. Under the optimum anaerobic conditions for fermentation of the chopped, dried woolly foxglove foliage at 37°C, the best yield of digoxin of 99-100% was achieved in 48 h. The optimal conditions for extraction of digoxin by percolation (plant particle size: 7 mm; height of foliage in the percolator: 30 cm; extracting solvent: 10%vol. ethanol- or methanol-water solution, volumetric percolate flow rate: 4 L/h and the percolate residence time in the percolator: 4h) ensured the digoxin extraction degree of 97%. Although ethanol is currently more expensive than methanol, it is recommended as extracting solvent because of its lower toxicity. Therefore, the 10%vol. aqueous ethanol solution was recommended as the extracting solvent for recovering digoxin from the fermented woolly foxglove foliage. By further isolation and purification, a highly pure product fulfilling the requirements prescribed by pharmacopoeias was obtained.  相似文献   
5.
The composition of the leaves of cocoyam (Xanthosoma sagittifolium) and of two trees (Trichanthera gigantea and mulberry, Morus alba), their nutritive value in pigs and voluntary intake by pigs were determined. The average protein content ranged from 170 to 240 g kg?1 dry matter (DM) and that of neutral detergent fibres from 218 to 398 g kg?1 DM. The leaves are interesting sources of calcium (up to 69 g kg?1 DM), potassium, iron and manganese. The proteins are well balanced in essential amino acids, with lysine ranging from 43 to 57 g kg?1 proteins. The apparent faecal digestibility was determined by difference in 35 kg pigs fed a diet containing 35% leaf meal. The digestibility coefficients of DM, N and energy were, respectively, 47–57, 33–36 and 51–53%. The digestible energy value ranged from 1.674 to 2.037 kcal kg?1 DM. The voluntary intake of Trichanthera and Xanthosoma was measured in sows weighing 100 kg on average. The intake reached 3.4 kg fresh leaves day?1 (0.51 kg DM) and 1.0–1.1 kg dry leaf meal/day. It is concluded that low energy density is the main limiting factor of tree foliage for pig nutrition but that they are good sources of minerals and well‐balanced proteins. Copyright © 2005 Society of Chemical Industry  相似文献   
6.
以植物纤维做支撑的缓冲包装材料关键影响因素研究   总被引:1,自引:1,他引:0  
武军 《包装工程》2007,28(8):49-51,59
通过改变以植物纤维做支撑的缓冲包装材料关键助剂和主体支撑材料的用量,考察由此导致材料结构形态不同而引起力学性能的不同,从而获得关键助剂和支撑材料的最佳配比及材料的最佳的缓冲性能.  相似文献   
7.
全球生态学的定量基础方法之一是森林测量学,它正在不断促进全球生态计划和国际森林监测技术水平的发展.然而,传统的方法也带来了一定的偏差,例如:在欧洲,由于大气污染的影响,当森林生物量增长时,也会引起森林郁闭度的降低.文章通过利用生物或生态基础理论与技术,尝试建立解决这类矛盾的方法.通过将通道输送模型理论与树木同化分配的概念相结合,即利用树木同化物质在树木木质部和韧皮部传输的特性进行测量,与树木同化产生的绿叶生物量进行分离,得到显示大气污染对区域性环境影响的信息.新方法以这些信息为基础建立的阚值水平标准,可以对大气污染状况进行指示.并利用森林生物产量的损失情况,对大气污染破坏林地生产量进行了评价.研究表明,该方法可以用于立法标准和大气污染控制信贷体系的构建,促使自然保护组织监管企业环境污染和安全生产带来的危害.  相似文献   
8.
蕨麻的开发现状及展望   总被引:2,自引:0,他引:2  
综述了蕨麻在食品、药物、饲料方面的开发现状,通过对当前开发状况的分析,指出了蕨麻今后开发的重点。  相似文献   
9.
A total of 68 species of starchy foods, tropical fruits, leaves and tubers (101 samples), were collected on the foothills of the Colombian Andes and in the rain forests of the Colombian Pacific coast. Their edible portion was analyzed for mineral content (Ca, P, Mg, K, Na, Cl, S, Mn, Zn, Fe, Cu, Se, Co, Ni). The foods were generally high in K (36–1.782 mg K/100 g edible portion) and low in sodium (<45 mg Na/100 g edible portion). The tree foliages had the highest contents in most of the elements, especially in calcium (280–1242 mg Ca/100 g edible portion, i.e., up to 62 g Ca/kg dry matter) and iron (0.7–8.4 mg Fe/100 g edible portion). Correlations (P < 0.001) were observed between total ash and many elements, especially Ca and Mg (r =  0.77 and 0.73, respectively). High correlations were also obtained between Ca and Mg (r = 0.93).  相似文献   
10.
叶簇穿透(FOPEN)雷达是一种用于发现和表征密集叶簇下人为目标及表征叶簇自身的技术手段。这种雷达已经在军事监视和民用地理空间成像方面得到应用。本次讲座分为三大部分:第一部分讲述FOPEN雷达的早期历史,主要讲述战场监视及叶簇穿透雷达的早期试验。其中,某些雷达技术的发展意义重大,支撑探测密集叶簇下面固定和移动目标的能力。这些技术中最重要的部分就是众所周知的相干雷达与数字处理技术。同样重要的是雷达穿透叶簇的量化及其散射损耗影响。第二部分重点讨论了几种军民用FOPEN合成孔径雷达系统及其研究成果。在对每种雷达系统概述过程中还通过举例说明SAR图像及其固定目标探测能力。这一部分还给出了量化极化分集在探测和表征人为和自然目标时的好处。在目标描述与降低虚警方面,极化技术的优势明显。最后讨论了超宽带和超宽角成像技术。第三部分讨论的是多模超宽带雷达最新研究及SAR和动目标显示(MTI)FOPEN系统的设计。重点是设计这些超宽带(UWB)系统的优势和困难,以及实际电磁环境下的工作情况。讲座最后两部分阐述了文献中出现的一些用于未来多模式工作的新技术:探测可辨别低速运动目标的需求;双基地SAR与固定GMTI照射波形的协同工作。  相似文献   
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