木耳高产栽培配方的数学模型及优化研究

崔文善，闫培生，张金政．木耳高产栽培配方的数学模型及优化研究．数理统计与管理，１９９７，１６（４），８～１１．本文采用回归正交设计方法，研究了泡桐木屑栽培木耳的配方组合与产量之间关系，并建立了数学模型。结果表明，以泡桐木屑为主料，各组分的适宜用量，以及它们之间合理组合，可显著提高木耳产量，降低生产成本，并具有较好的稳定性；其配方的优化方案为：泡桐木屑７７．６～８０．２％，麦夫１２．５～１４．８％，石灰２．４～２．７％，ＭｇＳＯ４１．３％，ＫＨ２ＰＯ４２．６％，糖１．０％。     

Boundary Value Problems for Nonlinear Differential Equations of Second Order inBanach Spaces

ＢａｎａｃｈＳｐａｃｅｓＢｏｕｎｄａｒｙＶａｌｕｅＰｒｏｂｌｅｍｓｆｏｒＮｏｎｌｉｎｅａｒＤｉｆｆｅｒｅｎｔｉａｌＥｑｕａｔｉｏｎｓｏｆＳｅｃｏｎｄＯｒｄｅｒｉｎＢａｎａｃｈＳｐａｃｅｓＣｕｉＣｈａｎｇｊｕｎＬｉｕＹａｎｓｈｅｎｇ（Ｄｅｐｔ．ｏｆＭａ...     

K0超固结土的不排水抗剪强度

结合K0超固结上模型、旋转角w公式、临界状态不排水条件以及基于SMP的变换应力张量建立了不排水抗剪强度的统一表达式;采用三轴压缩、三轴拉伸的应力洛德角θ、旋转角w建立了三轴压缩、三轴拉伸条件下的不排水抗剪强度公式;基于临界状态士力学,推导出了平面应变条件下的应力洛德角θ、旋转角w的表达式,进而得到平面应变条件下的不排水抗剪强度公式.分别采用三轴压缩、三轴拉伸和平面应变条件下试验数据对所提出的不排水抗剪强度公式进行验证,预测结果和试验数据的基本吻合表明了不排水抗剪强度公式的合理性.     

随机参数智能桁架结构动力特性分析

文中针对随机参数压电智能桁架结构研究了基于概率的结构动力特性分析方法。建立了压电主动檑和被动杆结构材料的质量密度、弹性模量同时具有随机性时结构的刚度矩阵和质量矩阵；从结构振动的瑞利商表达式出发，利用代数综合法推导出结构特征值随机变量数字特征的计算表达式。最后通过两个算例考察了智能桁架结构物理参数的随机性对其动力特性的影响，并获得了一些有意义的结论。     

加热炉内板坯粘塑性下桡变形的研究

在加热妒内，由于高温及重力作用，板坯两端的悬臂将产生下桡变形。悬臂越长，下桡将越大，导致悬臂下桡部分与出口端墙相碰，影响出料而造成事故。本文对加热炉内板坯的下桡变形进行了分析计算。首先，建立了板坯的二维非稳态导热模型并用有限差分法计算了炉内板坯随时间的温度变化；然后建立了板坯悬臂粘塑性变形模型，用有限元法计算了高温条件下由重力引起的悬臂的下桡变形。由此理论模型计算出的板坯抽出温度与悬臂端下桡量与实测结果吻合良好，说明该理论模型及模型计算方法是正确的，可用于对装钢生产进行指导。     

Characterisation of martian soil simulants for the ExoMars rover testbed

The European Space Agency (ESA) ExoMars mission involves landing a rover on the surface of Mars on an exobiology mission to extend the search for life. The locomotion capabilities of the ExoMars rover will enable it to use its scientific instruments in a wide variety of locations. Before it is sent to Mars, this locomotion system must be tested and its performance limitations understood. To test the locomotion performance of the ExoMars rover, three martian regolith simulants were selected: a fine dust analogue, a fine Aeolian sand analogue, and a coarse sand analogue. To predict the performance of the ExoMars rover locomotion system in these three regolith simulants, it is necessary to measure some fundamental macroscopic properties of the materials: cohesion, friction angle, and various bearing capacity constants. This paper presents the tests conducted to determine these properties. During these tests, emphasis was placed on preparing the regolith simulants at different levels of density in order to evaluate its impact on the value of the parameters in particular. It was shown that compaction can influence the Bekker coefficients of pressure-sinkage. The shear properties are consistent with the critical state model at normal stresses similar to those of the ExoMars rover in all but one of the simulants, which showed behaviour more consistent with transitional soil behaviour. It is necessary to give due consideration to these variations to ensure a robust test regime is developed when testing the tractive ability of the ExoMars mobility system.     

Design of state estimator for uncertain neural networks via the integral-inequality method

The issue of state estimation is studied for a class of neural networks with norm-bounded parameter uncertainties and time-varying delay. Some new linear matrix inequality (LMI) representations of delay-dependent stability criteria are presented for the existence of the desired estimator for all admissible parametric uncertainties. The proposed method is based on the S-procedure and an extended integral inequality which can be deduced from the well-known Leibniz–Newton formula and Moon’s inequality. The results extend some models reported in the literature and improve conservativeness of those in the case that the derivative of the time-varying delay is assumed to be less than one. Two numerical examples are given to show the effectiveness and superiority of the results.     

Spatial behavior of an epidemic model with migration

It was reported that there are traveling patterns in the spatiotemporal data of epidemics (Cummings et al., Nature 427:344, 2004; Grenfell et al., Nature 414:716, 2001). To well understand the mechanism, we present a spatial epidemic model with migration, which means that the individuals exhibit a correlated motion toward certain direction, and obtain traveling pattern. Our results may be helpful to understand the mechanism of the spatiotemporal epidemics and have potential application of control of the epidemics.     

Numerical investigation of the effects of structural geometric and material nonlinearities on limit-cycle oscillation of a cropped delta wing

This article presents numerical simulations of the limit-cycle oscillation (LCO) of a cropped delta wing in order to investigate the effects of structural geometric and material nonlinearities on aeroelastic behavior. In the computational model, the structural part included both the geometric nonlinearity that arises from large deflections, and the material nonlinearity that originates from plasticity. The Euler equations were employed in the fluid part to describe the transonic aerodynamics. Moreover, the load transfer was conducted using a 3-D interpolating procedure, and the interfaces between the structural and aerodynamic domains were constructed in the form of an exact match. The flutter and LCO behaviors of the cropped delta wing were simulated using the coupling model, and the results were compared with existing experimental measurements. For lower dynamic pressures, the geometric nonlinearity provided the proper mechanism for the development of the LCO, and the numerical results correlated with the experimental values. For higher dynamic pressures, the material nonlinearity led to a rapid rise in the LCO amplitude, and the simulated varying trend was consistent with the experimental observation. This study demonstrated that the LCO of the cropped delta wing was not only closely related to geometric nonlinearity, but was also remarkably affected by material nonlinearity.