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平房仓磷化氢膜下环流熏蒸技术的应用研究 总被引：1，自引：1，他引：1
德清国家粮食储备库的南11号、北13号和北11号平房仓分别进行了熏蒸前气密性测定和粮堆薄膜单面封情况下的磷化氢环流熏蒸技术的试验研究。通过粮面薄膜单面密封技术与环流熏蒸技术的良好结合,加强了熏蒸粮堆的气密性,缩小了熏蒸空间,不仅节约了用药量,而且还使环流效果更好。气密性测定结果表明在负压状态下,从-500Pa上升到-250Pa时,3个仓压力半衰期(t1/2)分别为54、48和46秒,均超过我国环流熏蒸推荐的气密性标准。膜下环流熏蒸试验期间的浓度测定表明,在这种气密性条件下,3个仓的磷化氢平均浓度降低到0．02mg/L左右的时间分别为26、23和18天,总CT值分别为165．63、134．36和109．37(mg 相似文献
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对试验仓房的主要漏气部位进行气密改造后测试,仓房的压力半衰期t1／2从改造前45S延长至66s。对空仓进行磷化铝投药试验,连续56d每天定时检测磷化氢浓度变化,其浓度半衰期（从174mL／m^3降至87mL／m^3）为31d。装粮后与对照仓同时进行磷化氢环流熏蒸试验,在外部条件相同的情况下,对熏蒸过程中仓房气体浓度进行定时检测,并对其数据进行整理、比较、分析,得出经过气密性改造的仓房能够更长时间保持有效熏蒸浓度的结论。 相似文献
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研究气密性良好、存在刚性孔、存在柔性孔等3种情况下的模拟粮仓在不同初始压强下的压力半衰期变化情况。得出：①在相同孔径下,粮仓压力半衰期的时间随着初始压强的减小而减小;②对孔径、初始压强、压力半衰期进行回归分析,得出压力半衰期与初始压强、孔径二者均成二阶多项式的关系。500Pa-250Pa的半衰期与孔径关系可表达为：y=756．63x^2—1087．7x＋485．77,R^2=0．9864。 相似文献
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仓房气密性与磷化氢环流熏蒸用药量及浓度的相关性 总被引：6，自引：2，他引：4
本文报告了国家粮食局储粮新技术生产性试验中关于仓房气密性与磷化氢环流熏蒸用药量和浓度相关性的主要试验结果。生产试验表明：当仓房气密性达到一定程度后，在试验粮情条件下，投入较少的磷化铝即可使仓内浓度得到有效保持，并取得较好的杀虫效果。采用仓外投药时，粮堆内各测点磷化氢浓度约20小时后基本均匀，且均匀性保持较好，最低最高浓度比值较大，一般都在0.8以上。当熏蒸期间仓内磷化氢浓度不足时，可以很方便地进行补充投药。采用表面施药方式时，磷化氢浓度上升和达到均匀的时间都比较慢，仓内各点浓度达到100mL/m^3以上需要2-3天，各点浓度均匀需3-5天。自然潮解施药由于药剂中磷化氢是缓慢放出的，即使在投药相当时间后还会有磷化氢补充到熏蒸环境中，这就使得仓内整体磷化氢浓度下降较慢，总体上保持有效浓度的时间延长且时间后移。本文还对磷化氢环流熏蒸应用中的相关问题进行了探讨。 相似文献
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Considering the nonhomogeneity and anisotropy of the undrained shear strength of soft clay, the face stability of shield tunnel was studied by upper bound limit analysis, and the formula for calculating the limit support pressure was obtained. The influences of nonhomogeneity and anisotropy on the limit support pressure amplify with each other.The relationship between limit support pressure and tunnel depth also depends on the nonhomogeneity and anisotropy; the limit support pressure reaches maximum value at a certain tunnel depth when nonhomogeneity and anisotropy are strong enough. These results show the nonhomogeneity and anisotropy of clays cannot be neglected when analyzing the stability of tunnel face. 相似文献
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For the safety of salt rock underground deposit, uncertainties and their influences are considered, and failure probability during operation period is analyzed. Based on finite element model, equation of limit state surface is transformed into explicit equation by response surface method. Combined with Monte Carlo method, computation efficiency is improved. The deposit could be simulated as a series-parallel system. The element with highest failure probability is determined first, then failure mode and system reliability are computed. Taking Jintan underground gas deposit as an example, the analysis indicates that as storage pressure increases, failure probability of middle part of deposit decreases firstly, then increases gradually when storage pressure accumulates to a certain extent. The failure probabilities of upper part and underside of deposit increase as storage pressure increases. During operation period, controlled failure mode is shear failure of upper part and underside of deposit under high storage pressure. In conclusion, the storage pressure during operation period should be controlled strictly. 相似文献
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苹果郁闭园不同间伐方式对果树群体结构和果实品质的影响 总被引：7，自引：2，他引：7
以成龄‘红富士’苹果郁闭园为试材,设计隔行间伐（处理A）、隔株间伐（处理B）、行内隔3去1间伐（处理C）3种处理和对照(CK),研究它们对果树群体结构和果实品质的影响。结果表明：与对照相比,各间伐处理的枝类组成得到了不同程度的优化,叶丛枝、短枝和长枝比例增加,徒长枝比例减小;3个处理的每公顷的总枝量、树冠覆盖率开始时下降明显,以后逐年恢复;处理A的行间交接率明显下降,而处理B的株间交接率下降明显;各处理的叶面积系数降低,叶片变大,百叶厚度增加;果园的通透条件明显改善。间伐处理的果实外观品质如单果重、色泽、着色面积、优质果率均明显的好于对照;果实的内在品质如含糖量增加、滴定酸含量下降、硬度增大,果实的风味和质地等也都优于对照。试验得出结论,适宜的间伐方式可从根本上改善苹果郁闭园的群体结构,提高果实品质,各间伐处理的综合效果以处理B最佳,处理A次之。 相似文献
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The constitution, design ideas and working principles of the DDC experimental system for testing dynamic tensile stress of outside body cell using membrane variable stress wave are discussed in detail. A new design measure is put forward, i.e. using airtight liquid for transferring pressure, and a space mechanism which is made up of two moveable linking axes and controlled by DDC for producing dynamic tensile stress with variable stress wave. The space mechanism is made up of two moveable linking axes, the first axis is controlled by an alternative current servo system, at the same time it drives the modulating modulating disc, and its rotation velocity is uniform and adjustable, so the rotating velocity of the disc can be controlled. Second, the hydraulic pressure worktable is driven by step electric motor. By dynamically changing the relative position of the modulating disc and the worktable, the journey of the piston in hydraulic pressure vat can be changed accordingly. The resultant motion of the modulating disc rotation and the radial direction relative movement of the piston can create liquid pressure with variable frequency and amplitude range, and the pressure can be changed into membrane tensile stress with variable frequency and pressure amplitude range using pressure fine tuning, and muhi-path disporting pressure. The system is proved to be simple, reliable, economic and controlled expediently by the experiment conducted. 相似文献
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According to the extensive theory of topological degree for set-valued mapping ,the authors derive the topological degree for upper semicontinuous set-valued 1-set-contractive mapping. With the topological degree, the fixed theorems for upper semicontinuous set-valued 1-set-contractive mapping is studied. 相似文献
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This paper studies the landslide mechanism by the analysis of accumulation form, topography and geomorphology, self structure and natural river system of Weijiagou coal gangue hill. The limit state function is established based on plasticity mechanics limit analysis upper bound theorem and Bishop slices method, combining reliability theory. The safety coefficient and reliability index of Weijiagou coal gangue slope is calculated. The plasticity limit analysis upper bound theorem can consider the interior stress strain relation of soil, so the formula derivation process is stricter. It is the consideration of the variability of gangue parameters that making the evaluation result more reasonable. 相似文献
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通风隔热对立筒仓安全储粮的作用 总被引：2，自引：0，他引：2
根据立筒仓储粮粮情变化规律,结合实际工作经验,在筒仓围护结构改造基础上,利用冬季低温天气,进行通风降温,并在气温回升之前对降温仓进行隔热密闭。通过两年多的筒仓储粮实践表明,通风降温、密闭隔热储藏技术对立筒仓长期安全储存小麦有积极的作用。 相似文献