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In recent years, the round deep foundation pits engineering gradually appears in Chengdu Plain whose strata are mainly sand-cobble soils. However, there are no proper calculation methods of earth pressure in retaining structure like this and distribution mode of the pressure is unknown. With the use of elastoplastic numerical simulation method involved in interaction between retaining piles and soil, the distribution law of earth pressure of the round deep foundation pit retaining structure is determined. The result shows that distribution of earth pressure on a pile is triangular and the maximum lies in the location of pit bottom, but the average value of the pressure is less than Rankine active earth pressure. Model tests have also been carried out so as to verify the distribution mode. As for the test model, the values obtained by the numerical simulation method are approximately similar to the experimental results in the distribution law as a whole, which to some degree suggests the rationality of the numerical simulation results. 相似文献
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1980—2014年潍坊市深层地温对气候变化的响应 总被引:1,自引:1,他引:1
为了研究潍坊深层地温对气候变化的响应,利用潍坊市1980—2014年0.8~3.2 m地温资料,运用线性倾向估计、Mann-Kendall和滑动t检验等统计方法,对潍坊市近35年深层地温的变化特征进行分析。结果表明:0.8~3.2 m地温变化趋势不显著,均未发生突变,一年中,仅夏季各深层地温呈增温趋势。年代际变化上,1980s和2010s各层平均地温均高于1990s和2000s。深层地温在冬季随深度增加,稳定性渐好,夏季反之,一年中,稳定性最好和最差分别发生在夏季和冬季0.8 m地温层。气温对深层地温的影响明显,季、年平均气温与同期各深层地温多呈正相关,随着深度的增加,气温与各层地温的相关性略有降低,这是深层地温变化存在滞后性所致,降水量对各深层地温影响不大。 相似文献
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The simulation analysis of temperature field under ideal condition can reflects the rule of true temperature field, but accidental factor during construction process will result in difference of the result. This paper studied the Baise RCC Dam with the distributed optical fiber technology and FEM technology, the numerical results were modified with the testing data and the contrastive curves can be obtained for the testing data,ideal simulation data and real -time simulation data. The results indicate that the modified real - time simulation can reflect the true temperature field ; it may serve as a guide for the temperature control. 相似文献
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烯效唑与稀土复配剂对黄瓜生长发育和产量的影响 《中国农学通报》2006,22(1):208-208
在初花期喷施不同浓度的烯效唑和农用稀土复配剂,初步研究了复配剂对黄瓜生长发育和产量的影响,结果表明:复配剂可降低株高,延缓衰老;使结瓜期叶片中比叶重和叶绿素含量增加,光合速率增强;对黄瓜产量有显著的增产作用,以复配剂A3B2进行处理的效果最佳,增产幅度高达27.04%;促进增产的主要原因是提高了单瓜重,其次是单株结瓜数。 相似文献
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喷放稀土对甘蔗植株ATP酶和根际土壤酶活性的影响 总被引:5,自引:0,他引:5
本文研究了在甘蔗分蘖末期喷施稀土对甘蔗植株ATP酶和根际土壤酶活性以及根际细菌数量的影响。结果表明,分蘖末期喷施稀土提高了甘蔗叶片的Mg2+-ATP酶、Ca2+-ATP酶和根细胞的Na+-K+ATP酶的活性。提高了叶绿素含量、光合还礼经和根系活力,使土壤中有益的根际细菌数量增加,土壤酶活性提高,促进了甘蔗生长,提高了甘蔗产量。 相似文献
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大田定位试验结果表明,有机无机肥配施可提高水稻根系活力,减缓旗叶叶绿素和蛋白质的降解,延缓水稻旗叶衰老,提高水稻分蘖成穗率、结实率、千粒重和水稻产量。此外,有机无机肥配施还可提高红壤性水稻土的土壤肥力,改善土壤物理性状,是红壤性水稻土培肥和增产的有效措施。 相似文献
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稀土元素对小麦芽鞘生长及内源吲哚乙酸含量的影响 总被引:2,自引:0,他引:2
本文研究了稀土元素对小麦芽鞘生长,吲哚乙酸氧化酶活性,过氧化物酶同工酶,内源吲哚乙酸水平的影响.结果表明:100ppm—1000ppm的硝酸稀土可促进小麦芽鞘的生长,尤以1000ppm浓度明显.这种生长的促进伴随着吲哚乙酸氧化酶活性的增加,过氧化物酶同工酶带数目的增多及内源吲哚乙酸水平的下降.稀土元素也可加强外源吲哚乙酸对小麦芽鞘生长的促进,抵消外源脱落酸对芽鞘生长的抑制. 相似文献
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Compared with the traditional welding truss-column in shape of A, the members of the bolting top-joint are much smaller than the common welding joint. Furthermore, the members are more convenience on fabrication, transportation and installation. It should be noted that the zinc process is much easier and cheaper. In this paper, by using the finite element method, the effect of many factors to the global stiffness and the intensity of the bolting truss-column are analyzed; the factors include the column height, the root width to column height ratio, the tube thickness, etc. The results obtained are favorable references for design and optimization of the bolting 相似文献
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LUO Xian-cheng 《保鲜与加工》2000,(4):95-98
On the basis of trial and theory, this paper advances an effective preventive measure to solve the problem of producing black smoke during fuel oil thermolysis and polluting the atmosphere in the process of combustion. It provides valuable references to protect the environment,save energy and solve the problem of clean combustion of high-hydrocarbon fuel, especially fuel oils such as kerosene, diesel oil, heavy oil etc. 相似文献
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采用盆栽试验,通过叶面喷施不同浓度的稀土微肥,研究其对旺长期干旱胁迫下烤烟生育及生理特性变化的影响。结果表明,低浓度(50、100mg/L)稀土微肥促进烤烟根系发育,明显提高根系活力和根系生物量,高浓度(300mg/L)则表现出一定的抑制作用。不同浓度的稀土微肥均能提高烤烟超氧化物歧化酶和过氧化物酶活性,维持过氧化氢酶活性,增强脯氨酸和可溶性蛋白积累能力,但随浓度提高效果不明显,甚至起反向作用。其中100mg/L稀土微肥处理对促进烟株生长与烟叶开片、提升抗逆能力表现最为突出,提高了烤烟抗旱能力。 相似文献
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以污泥浸提液中添加不同浓度的稀土镧对黑麦草和高羊茅浸种,研究了污泥浸提液和稀土镧对2种草坪草种子萌发及其初期生长的影响.结果表明,污泥浸提液与不同浓度稀土镧混合浸种对黑麦草和高羊茅的萌发和初期生长均有促进作用.从种子萌发来看,200 mg/L镧+污泥浸提液处理下,黑麦草种子活力指数最高,较对照增加了71.4%,而高羊茅在100 mg/L镧+污泥浸提液处理下最高.稀土镧+污泥浸提液处理能显著促进2种草坪草幼苗株高生长,与对照相比,200 mg/L镧+污泥浸提液处理在播种后第5天黑麦草和高羊茅的株高分别增加了33.4%和24.7%.黑麦草和高羊茅的地上干重分别在300 mg/L镧+污泥浸提液处理和200 mg/L镧+污泥浸提液处理下达到最大.从叶绿素含量来看,300 mg/L镧+污泥浸提液处理下最高,黑麦草的叶绿素a和总叶绿素含量分别高出对照20.6%和18.4%,而高羊茅分别比对照高43.7%和34.4%. 相似文献
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A numerical method calculating the forward problem of electrocardiogram (ECG) has been presented. By using this method, the torso part including anisotropic muscle layers has been discretized by means of the finite element method (FEM). The rest of torso have been divided into the surface elements by the boundary element method (BEM). The effects of the skelltel muscle layers over thorax wall, have been discussed in terms of a three-dimensional torso models. 相似文献
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以大豆油为研究对象,通过油温180℃,时间20 h条件下反复煎炸薯片操作中大豆油品质评价指标的测定发现,随着煎炸时间延长,大豆油脂肪酸组成中饱和脂肪酸含量由15.88%上升至22.40%,不饱和脂肪酸由84.05%下降至77.57%。在煎炸过程中,大豆油的色泽加深,黏度增加,游离脂肪酸、过氧化值、p-茴香胺值和总极性物质含量显著升高(p<0.05),接触角在煎炸过程中随着煎炸时间的延长呈现极显著的线性降低(p<0.01),即润湿性增强现象。由此可见,大豆油在反复煎炸操作中,游离脂肪酸、极性物质和聚合物等物质的大量形成,促使油脂品质发生劣变。 相似文献