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排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Production of high strength Al-Zn-Mg-Cu alloys by spray forming process 总被引:15,自引:2,他引:13
1 INTRODUCTIONAl Zn ( 7×××series)alloyshavebeenwidelyusedbecauseofhighstrength ,corrosion resistanceandothergoodproperties[1 ,2 ] .Butapracticalcontentlimitof7%Zn (alloys 70 75,71 75and 7475etc)isimposedforconventionalcastmaterialsbecauseofso lutemacro segregationandcoar… 相似文献
992.
L. SMITHSON D.C. GRAHAM P.R. CLINGELEFFER 《Australian Journal of Grape and Wine Research》2011,17(2):153-161
Background and Aims: Despite much anecdotal evidence, there has been little scientific investigation of the potential effects of a high‐temperature event on grapevines during deficit irrigation. This study examined the interaction between temperature and water status on leaf physiology. Methods and Results: Two experiments used Cabernet Sauvignon cuttings grown in a glasshouse at approximately 27–30°C before deficit irrigation treatments were imposed. When water stress was apparent, a 2‐day high‐temperature event with maximum daytime temperatures of approximately 40–45°C was generated. Leaf damage, stomatal conductance and water potential of deficit‐irrigated vines were all affected to a greater extent than in the well‐watered vines. Conclusions: The negative effects of a high‐temperature event on vine physiology were more severe in vines experiencing water stress than in well‐watered vines, but recovery was rapid even without re‐watering. Significance of the Study: An increase in the use of deficit irrigation will lead to a greater likelihood of vines being water stressed on hot days, and the observed responses indicate that this will result in greater damage to the vine. 相似文献
993.
Abstract There has been a growing consciousness for the need for a framework that is holistic and comprehensive in the assessment of irrigation system performance. This paper presents the results of statistical tests conducted on the analytical framework developed in Part 1 of the paper to examine whether or not it addresses the important issues of system performance. Information collected from two farmer-managed irrigation systems of Nepal was used to test the validity of the framework. The empirical evidence shows that the framework is valid in identifying and fitting conventionally-overlooked livelihood assets and that it demonstrates differences in farm households' access to these assets resulting in varying performance of irrigation systems. 相似文献
994.
Characteristic of cold sprayed catalytic coating for hydrogen production through fuel reforming 总被引:1,自引:0,他引:1
Cold spray was employed as a novel method to prepare NiO/Al2O3 primary steam reforming catalyst coating for hydrogen production. The coating microstructure was characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM) before and after reforming reactions. The catalytic coating performance was examined through methane steam reforming (SRM) in a microreactor. Results showed that NiO/Al2O3 coating was successfully deposited on the stainless steel substrate by cold spray. The thickness of the coating was about 50 μm. It presented a rough surface and porous structure. Since temperature of the cold spray process is low, no phase changes occurred to NiO/Al2O3 during deposition. However the particle size in the coating became smaller compared with the feedstock due to its smashing. It was found that the cold-sprayed catalytic coating was active for SRM at high space velocity although filamentous carbon was formed on its surface. After reaction there was no obvious peeling off of the coating indicating a good bonding between the coating and substrate. 相似文献
995.
宁咏梅 《安徽水利水电职业技术学院学报》2012,12(2):49-50,56
文章分析了电力排灌站电气设备预防性试验结果的异常现象,提出了相应的处理方法。 相似文献
996.
随着食品市场多样化的发展,咸味香精不仅仅局限于液态和膏状,利用美拉德反应配合人工调配的氧化油脂和微乳化工艺,再经离心喷雾干燥而成的粉末香精,既保留了通过美拉德反应的逼真肉香,又能通过乳化包埋、喷雾干燥得到风味浓郁、使用方便的食品香精。 相似文献
997.
A. ZERIHUN D.M. LANYON M.R. GIBBERD 《Australian Journal of Grape and Wine Research》2010,16(1):237-242
Background and Aims: Variability in vine vigour is a commonly observed feature in vineyard blocks. Although this aspect is well recognised among viticulturalists, impacts of vigour variability on vine function and resource use efficiency are seldom considered in management decision-making. This study examined influences of vine vigour variability on vine physiological performance and resource use in a commercially managed vineyard block. Methods and Results: The vineyard block was divided into different vigour zones using plant cell density data derived from aerial multi-spectral imaging of the study block. Gas exchange and under-vine soil moisture status were measured in some of the vigour zones. Low vigour vines had consistently lower photosynthesis and stomatal conductance rates than high vigour vines. The differences were evident both during soil-drying and rewetting. Similarly, irrigation water utilisation was markedly lower in low than in high vigour vines. Vine fruit yield was linearly and positively related to vines' capacity to utilise applied water. Conclusions: Vigour has considerable influence on vine physiological performance and on resource utilisation capacity. Uniform irrigation application to a block with variable vigour (which is the norm currently) leads to spatially inefficient resource use, and consequently to a marked within-block variation in irrigation water productivity. Significance of the Study: The demonstration that variation in vigour has a corresponding effect on resource utilisation has direct relevance for managing vineyard inputs such as irrigation or fertilisers. 相似文献
998.
Talita A. Comunian Ednelí S. Monterrey‐Quintero Marcelo Thomazini Julio C. C. Balieiro Pierpaolo Piccone Paola Pittia Carmen S. Favaro‐Trindade 《International Journal of Food Science & Technology》2011,46(6):1259-1265
The aim of this research was to study spray drying as potential action to protect chlorophyllide from environmental conditions for shelf‐life extension and characterisation of the powders. Six formulations were prepared with 7.5 and 10 g of carrier agents [gum Arabic (GA), maltodextrin (MA) and soybean protein isolate (SPI)]/100 mL of chlorophyllide solutions. The powders were evaluated for morphological characteristics (SEM), particle size, water activity, moisture, density, hygroscopicity, cold water solubility, sorption isotherms, colour and stability, during 90 days. All the powders were highly soluble, with solubility values around 97%. A significant lower hygroscopicity was observed for GA powders, whilst the lower Xm values obtained by GAB equation fitting of the sorption isotherms was observed for the 7.5 g MA/100 mL samples. All formulations, but the 1 (7.5 g SPI/100 mL of chlorophyllide), provided excellent stability to the chlorophyllide during 90 days of storage even at room temperature. 相似文献
999.
介绍了钢管表面高压水除鳞系统的工作原理;分析了影响钢管表面高压水除鳞效果的设备问题;探讨了钢管表面生红锈的化学机理。通过改进高压单向截止阀设计和曲轴进油口的密封形式,并通过实验对比选择小直径喷嘴解决了钢管表面生红锈的问题,并在保证钢管表面不生红锈的同时取得了良好的除鳞效果。 相似文献
1000.