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41.
玉米籽粒品质性状及其相互关系分析 总被引:5,自引:1,他引:5
通过测定55个玉米品种(系)籽粒的物理性状、淀粉品质及蛋白质组分,分析它们之间的简单相关关系。结果表明:容重与各淀粉组分含量呈负相关,与角质率、低谷粘度、最终粘度、回冷值、峰值时间、糊化温度呈极显著正相关;角质率与醇溶蛋白、谷蛋白、总蛋白含量及峰值时间和糊化温度呈极显著正相关,与膨胀势、峰值粘度和稀懈值呈显著负相关;直链淀粉含量与稀懈值负相关,与膨胀势、峰值粘度、低谷粘度、最终粘度、回冷值、峰值时间和糊化温度均表现一定的正相关;支链淀粉含量、总淀粉含量以及支/直比与糊化温度正相关,与其它粘度指标负相关;峰值粘度与低谷粘度、稀懈值、最终粘度和回冷值的相关程度较高,是衡量淀粉糊化特性的最重要指标;醇溶蛋白与总蛋白和粘度性状问的关系更密切,醇溶蛋白含量的变化对于总蛋白含量变化及淀粉特性的影响最大。文章还提出今后要加强支链淀粉、峰值时间、糊化温度和醇溶蛋白含量等对加工品质影响的研究。 相似文献
42.
茶多酚对肉源腐败菌和致病菌的抑制效果 总被引:3,自引:0,他引:3
研究了茶多酚对肉源荧光假单胞菌、鼠伤寒沙门氏菌、大肠杆菌、金黄色葡萄球菌的抑制效果。设计不同浓度茶多酚溶液(0.0%、0.5%、1.0%、2.0%、2.5%),采用滤纸片法评判抑制效果。结果表明,茶多酚溶液(0.5%、1.0%、2.0%、2.5%)对荧光假单胞菌有极显著的抑制效果(P<0.01),常用的防腐剂山梨酸钾(1.0%)对其抑制效果却不显著(P>0.05)。茶多酚溶液(1.0%、2.0%、2.5%)和山梨酸钾溶液(1.0%)对鼠伤寒沙门氏菌、大肠杆菌、金黄色葡萄球菌有极显著的抑制效果(P<0.01),茶多酚溶液(0.5%)对鼠伤寒沙门氏菌、大肠杆菌、金黄色葡萄球菌无显著的抑制效果(P>0.05)。通过茶多酚溶液的浓度与4种菌抑菌圈直径的直线相关图可以看出,茶多酚溶液的浓度与鼠伤寒沙门氏菌抑菌圈直径的相关系数最大,荧光假单胞菌次之,其次是金黄色葡萄球菌、大肠杆菌。 相似文献
43.
44.
森林植被截留降雨实验与模拟 总被引:1,自引:0,他引:1
根据半干旱地区樟子松林冠截留降雨的实测资料,对林冠截留与大气降雨之间的关系进行了分析。在几个假设的基础上,建立林冠截留及林内雨量的半理论半经验公式,并介绍了参数确定方法。经检验,公式的计算值与实测值取得较好的一致性,基本上反映出林冠截留降雨的一般规律,揭示了林冠对降雨截留作用的数量关系和客观实质。 相似文献
45.
《Engineering Fracture Mechanics》1987,26(1):127-141
An indirect boundary element method based on the superposition of the elastic fields of edge dislocations is derived. Elements having an arbitrarily specified distribution of dislocations is made possible through the use of a specialized numerical integration scheme. The method is applied to finite as well as infinite regions with single or multiple cracks. Sample results indicate that the method is well suited for multiply cracked problems in infinite regions, whereas a large number of degrees of freedom is required for the accurate solution of multiply cracked problems in finite regions. Implementation of the method to nonlinear boundary conditions is discussed. To demonstrate the applicability of the numerical method to nonlinear boundary condition problems, an analysis of the propagation of part-through crack problems in plates under in-plane loadings is performed through the use of the line spring technique and the present numerical method. 相似文献
46.
Yurong Ma Qingguo Wang Gyunghoon Hong Marita Cantwell 《International Journal of Food Science & Technology》2010,45(7):1486-1494
The cultivar Pacific Russet with high browning susceptibility was used for most testing. Controlled atmospheres (0.3%, 3% and 21% O2 in combination with 0%, 6% or 12% CO2) and anti‐browning chemicals were studied in relation to quality retention and wound‐induced phenolic metabolism of fresh‐cut slices for up to 16 days at 5 °C. The 3% O2+ 12% CO2 atmosphere was most effective among those tested, and retarded increases in phenolics and phenylalanine ammonia lyase activity, but had only slight benefit on visual quality. A 1.25% ascorbic acid +1.25% citric acid treatment was ineffective, but when combined with 3% O2+ 12% CO2, it was comparable with 0.025% sodium bisulphite. Bisulphite concentrations from 0.05% to 0.25% provided similar effective control of discolouration. Bisulphite as low as 0.025% with 3% O2+ 12% CO2 resulted in a visual quality score at the limit of marketability after 8 days at 5 °C. Chemical treatments did not retard increases in phenolic concentrations or phenolic enzyme activities. 相似文献
47.
针对传统的单一水位流量关系曲线高水延长方法的缺陷,以泗洪站为例,采用多层递阶和回归分析相结合的方法,对稳定水位流量关系曲线进行了高水延长计算。结果表明,该模型精度较高,并可通过计算机编程计算,提高了工作效率。 相似文献
48.
Gabriel N. Gatica Ricardo Oyarzúa Francisco-Javier Sayas 《Computer Methods in Applied Mechanics and Engineering》2011,200(21-22):1877-1891
In this paper we develop an a posteriori error analysis of a new fully mixed finite element method for the coupling of fluid flow with porous media flow in 2D. Flows are governed by the Stokes and Darcy equations, respectively, and the corresponding transmission conditions are given by mass conservation, balance of normal forces, and the Beavers–Joseph–Saffman law. We consider dual-mixed formulations in both media, which yields the pseudostress and the velocity in the fluid, together with the velocity and the pressure in the porous medium, and the traces of the porous media pressure and the fluid velocity on the interface, as the resulting unknowns. The set of feasible finite element subspaces includes Raviart–Thomas elements of lowest order and piecewise constants for the velocities and pressures, respectively, in both domains, together with continuous piecewise linear elements for the traces. We derive a reliable and efficient residual-based a posteriori error estimator for the coupled problem. The proof of reliability makes use of the global inf–sup condition, Helmholtz decompositions in both media, and local approximation properties of the Clément interpolant and Raviart–Thomas operator. On the other hand, inverse inequalities, the localization technique based on element-bubble and edge-bubble functions, and known results from previous works, are the main tools for proving the efficiency of the estimator. Finally, some numerical results confirming the theoretical properties of this estimator, and illustrating the capability of the corresponding adaptive algorithm to localize the singularities of the solution, are reported. 相似文献
49.
50.
In this paper, the mean square (MS) stability and exponential mean square (EMS) stability of multi-variable switched stochastic systems are investigated. Based on the concept of the average dwell-time and the ratio of the total time running on all unstable subsystems to the total time running on all stable subsystems, some sufficient conditions are given to ensure the MS stability and EMS stability of the switched stochastic systems involved. Further, for the switched stochastic control systems with all subsystems controllable or stabilizable, EMS stabilization controls and sufficient conditions on EMS stabilization are presented, and the convergent rates of the closed-loop systems are obtained. 相似文献