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YANG Zhuan yun 《保鲜与加工》2008,(5):58-62
Pavement structures will be damaged by subgrade soil movement around the pipes introduced by extra shallow underground pipe jacking. Soil layer deformation with shallow deposits on pipes during extra shallow underground pipe jacking is analyzed using 3D FEM. The effects on pavement deformation created by the friction between shield and soil, injection slurry, jacking forces and the vehicle loads are studied with a practical project. The analytical results show that the ground surface deformation is an uplift first followed by settling with the lower part of the cover moving faster than the upper layers. It is demonstrated by comparing computational results of FEM simulation and the observed data from the in situ test that these FEM models can be applied to real world engineering. Subgrade soil settling on extra shallow underground pipe jacking in a cross section will be stable when the shield has passed through a section with a length twice the diameter of the pipe. Horizontal surface subsidence along the lateral distribution is similar to a normal distribution curve, with the primary affected areas on both sides of the axis approximately 1.5 times the diameter of the pipe. 相似文献
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为了研究苜蓿、玉米和大豆3种茬口与施肥对连作大豆虫食率的影响,2003-2005年在黑龙江龙镇农场采用两因素有重复完全随机试验,3年的连作大豆虫食率结果表明,茬口主效应和施肥主效应的互作对连作大豆虫食率的影响不显著,并且二者互作的各组合虫食率变化也没有明显的规律;施肥主效应对连作大豆虫食率有显著和极显著的影响,但施肥类型和施肥量对连作大豆虫食率的影响也没有发现规律性;2003年和2004年茬口主效应对连作大豆虫食率影响不显著,但2005年茬口主效应对连作大豆虫食率有极显著影响,从3年分析结果看,大豆茬上连作大豆的虫食率都相应高于同年苜蓿茬和玉米茬上连作大豆的虫食率,说明连作大豆年分越长,虫食率有加重的趋势。 相似文献
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The span ratio and the ratio of section height to section thickness of column leg are selected, which mainly influence the shear effect of special shaped columns. Based on error analysis of the displacement at the tip of the columns, the flexibility of a fiber model for L shaped columns, T shaped columns, and cross shaped columns in the range of elasticity is studied. The columns are studied with and without shear effect. The correctness of the fiber model with the shear effect is shown, and the applicable range of the fiber model with the shear effect is presented. 相似文献
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柿子馒头生产工艺的研究 总被引：1，自引：0，他引：1
柿子馒头可作为一种保健食品,在国内有着广阔的市场。研究了采用一次发酵法工艺生产柿子馒头的柿子用量、不同的pH值、和面时间、压面次数、饧发时间等生产工艺对馒头品质的影响。 相似文献
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To understand the energy absorption property of aluminum foam-filled steel pipes and the energy absorption property affected by aluminum foam filler, the energy absorption ability and transverse compression property of steel pipes and aluminum foam-filled steel pipes are tested. The results show that the normal stress-strain curve of steel pipes is similar with that of cellular materials. The normal yield stress of a steel pipe with a large diameter under transverse compression is lower than that with the same wall thickness but a small diameter. The deformation mode of steel pipes can be changed by the filling of aluminum foam. The aluminum foam filler improve the energy absorption ability of steel pipes. The effect of aluminum foam density on the energy absorption ability of steel pipe is small, and the effect of pipe diameter on the energy absorption ability of aluminum foam-filled steel pipes is large. 相似文献
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不同处理方法对柴胡种子萌发的影响 总被引：8，自引：1，他引：7
对来自山西的黑柴胡种子进行温度、清水浸种、沙藏处理和KMnO4药剂处理试验,以研究不同条件对种子萌发率的影响。结果表明：柴胡种子萌发的适宜温度为20℃;沙藏7~12d能明显促进柴胡种子的萌发,但不能使萌发的启动日提前;清水浸种不能提高发芽率,但可使启动日提前;0.25%、0.5%、0.75%的KMnO4溶液处理对柴胡种子萌发具有不同程度的抑制作用。建议柴胡种子萌发的适宜处理为：在20℃下清水浸种12h,沙藏处理7~10d,发芽率和出苗率较高,苗子生长比较整齐。 相似文献
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Thermal stress is one of the important influence factors of crack and deformation for large-span bridge structures. Grounded on Shibanpo Yangtze River double line bridge and universal finite element program MIDAS-Civil with referring to specifications of China and British BS5400, above all, it is for this Bridge that the stress and deformation influence is studied by setting section temperature difference and system temperature change, afterwards, the effect on the newborn bridge is discussed by combining impact of the section temperature difference and the system-calefaction linearly , and then, the effect is compared with the impact brought by moving load. The results will have a certain extent value for the design of ShiBanpo double line bridge and other similar bridges. 相似文献
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不同浓度盐胁迫对转基因饲用甜菜种子萌发及幼苗生长的影响 总被引：2，自引：0，他引：2
通过不同浓度NaCl溶液处理转基因饲用甜菜种子及其幼苗试验，研究了盐胁迫下种子萌发、幼苗生长及胁迫解除后种子的效应，为盐土农业生产提供理论依据。结果表明，转基因饲用甜菜种子萌发的适宜Nacl浓度为50。150mmol/L，其中100mmoL／LNaCl胁迫下，种子发芽率最高，与对照相比高6．78％。随着盐胁迫浓度的升高，种子萌发延迟，萌发率也呈不同程度的降低。盐胁迫解除后，种子萌芽迅速，萌芽率提高，整齐度增加。转基因饲用甜菜幼苗在不同NaCl浓度胁迫下表现出的反应不同，高盐胁迫对抑制幼根生长影响较大。 相似文献
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Fifty-six accessions of multi-cut Egyptian clover were compared at four experiments under different environmental conditions; i.e. location and season. Considerable variation existed for all the characters studied. The genetic variance exceeded the environmental variance for all the studied traits. Heritability was high for all characters studied. The expected genetic advance from selection of the superior 10.7% of the accessions as calculated from the combined data reached to 16.10, 17.50, 5.20, 20.60, 3.52 and 21.00 for mean plant height, seasonal fresh forage yield, mean dry matter percentage, seasonal dry forage yield, mean protein percentage, and seasonal protein yield, respectively. Both phenotypic and genotypic correlations among traits showed that mean plant height was positively correlated with each of seasonal fresh forage yield, seasonal dry forage yield, mean dry matter percentage and seasonal protein yield, but negatively correlated with mean protein percentage. Negative correlation were also found between mean protein percentage with seasonal fresh and dry forage yield.
Over all experiments, pat-coefficient analysis revealed that seasonal fresh forage yield had the highest positive direct effect on seasonal protein yield (0.841), followed by mean dry matter percentage (0.461). The mean protein percentage showed the minimum direct (0.172) and indirect influence on seasonal protein yield. 相似文献
Over all experiments, pat-coefficient analysis revealed that seasonal fresh forage yield had the highest positive direct effect on seasonal protein yield (0.841), followed by mean dry matter percentage (0.461). The mean protein percentage showed the minimum direct (0.172) and indirect influence on seasonal protein yield. 相似文献
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地下渗滤系统中ORP影响作用与改善措施 总被引：1，自引：1，他引：0
氧化还原电位（ORP）是影响地下渗滤系统稳定运行的主要因素之一,对系统内部微生境和污染物处理效果有重要影响。因此,就地下渗滤系统中ORP对有机物去除、脱氮、除磷和微生物活性的影响作用,目前常用的干湿交替、基质组配、布水管复氧、分流比、植物复氧、土壤动物活动复氧和通风管复氧等改善ORP措施进行了总结归纳,表明各种措施都有一定的工程适用性。随着工艺研究的深入,多种改善措施将组合应用,新型基质填料的研发将会促进地下渗滤系统理论内涵、拓宽工程实践应用,工艺运行将会更加灵活。 相似文献
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Deformation of pipe during rotary-draw bending is studied theoretically and experimentally.The effect of main technical parameters on the change of wall thickness and section flattening are analyzed with plastic FEM software,meanwhile the variety of wall thickness and section flattening in different location of pipe are studied experimentally.The result shows: the smaller R/D,the bigger the wall thickness change.The effect of t/D on wall thickness change is weak.The dimension and position of the mandrel have a big impact on wall thickness and section flattening.The conclusion is helpful to improve the quality of the rotary-draw bending of pipe. 相似文献
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陆地棉产量构成因素条件变量分析 总被引：2，自引：1，他引：1
采用条件变量分析方法,对23个陆地棉品种（系）两年资料的棉花单株产量及其3个组分性状进行了分析,结果表明,单株铃数引起单株产量的变异最大,衣分引起单株产量的变异最小;衣分以外的其他因素与环境的互作对单株产量的影响最大,单株铃数以外的其他因素与环境互作对单株产量的影响最小;不同品种基因型效应不同,不同品种3个组分性状对单株产量的贡献也有所不同。 相似文献
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野生花生抗青枯病种质的发掘及分子鉴定 总被引：11，自引：0，他引：11
以花生属5个区组的79份野生花生种质为材料,系统鉴定了野生花生对青枯病的抗性反应,从中发掘高抗青枯病的种质15份,含匍匐区组种质3份、直立区组1份、异形花区组1份、花生区组8份、未命名种质2份,抗病材料频率达到19%,高于栽培种花生资源的抗性频率。通过SSR分析表明,在所获得的抗青枯病野生花生材料中,四倍体野生种A.monticola与栽培种花生的亲缘关系最近,其次为花生区组的二倍体野生种A.duranensis和A.chacoense。根据DNA扩增结果,绘制了抗青枯病种质的指纹图谱,明确了其SSR分子特性。 相似文献
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轮作对稻米品质的影响 总被引：1，自引：1，他引：0
通过采用连作与轮作对比试验的方法,研究了轮作对稻米品质的影响。结果表明：从外观品质上看,轮作与连作的早晚稻粒长、粒型无明显差异,轮作普遍增加了早稻的垩白粒率和垩白度。轮作对早稻的加工品质有一定改善作用,处理D表现最好。但晚稻加工品质则是连作普遍优于轮作。不同轮作方式对透明度级没有影响。早晚稻的水分含量和早稻碱消值级连作与轮作各处理无显著差异。连作处理的早稻直链淀粉含量低于轮作处理,胶稠度高于轮作处理。连作处理的晚稻直链淀粉亦含量低于轮作处理,而轮作处理C的晚稻碱消值级和胶稠度远高于连作处理A,均高出20%,且与连作差异显著。由此可见,轮作对水稻的蒸煮品质并没有改善作用,而连作的蒸煮品质反而好于轮作。 相似文献