非方广义系统降阶Wiener状态平滑器

应用时域上的现代时间序列分析方法,基于ARMA新息模型和白噪声估值器,研究了非方广义离散随机线性系统,应用射影理论和矩阵的分块理论,在假设1～3下,给出了一种渐近稳定的广义降阶Wiener状态平滑器.非方广义系统包含一般广义系统作为特例,且算法为降阶算法,避免了求解Riccati方程和Diophantine方程,因而减小了计算负担,便于实时应用.     

两传感器广义系统信息融合Kalman滤波器

基于矩阵理论和时域上的Kalman滤波理论,针对两传感器广义离散随机线性系统进行研究,运用矩阵约当分解,将一类广义系统化为正常系统,并利用标量加权准则下的最优信息融合Kalman滤波理论,给出一类两传感器广义系统Kalman信息融合滤波器,同单传感器情形相比,可大大提高滤波精度,具有实际应用价值。     

状态估计在最小方差控制中的应用

通过引入状态变量,将普通的控制系统改写为状态空间模型,应用时域上的现代时间序列分析方法和射影理论,基于ARMA新息模型和白噪声估值器,给出状态变量的滤波估值,并用状态变量的滤波代替控制系统中的观测,从而得到含有新息补偿的最小方差控制律,它比直接由控制系统得到的最小方差控制律更加准确,也更具应用价值。     

传感器数据融合中状态估计技术研究

状态估计是数据融合的主要任务之一,状态估计主要对目标的位置和速度的估计,本文主要介绍了应用Kalman滤波对目标进行状态估计,并应用Matlab仿真软件实现了卡尔曼滤波算法,进行了性能分析。提出了在数据融合仿真系统中应用扩展Kalman滤波算法对目标状态进行估计,提高了跟踪效果。     

复卷机退纸辊转动惯量补偿问题的分析

复卷机退纸辊转动惯量的补偿可以保证张力恒定,从而保证了复卷的质量.分析了稳态和变速过程中造成张力波动的主要因素以及如何实时补偿转动惯量以保证恒张力控制,并提出了实际中基于欧陆590控制器的转动惯量补偿系统.     

不同发展阶段生物医药企业估值方法的研究 ——基于私募股权投资的视角

私募股权投资近两年在我国资本市场异军突起.本文基于私募股权投资的角度对不同发展阶段的生物医药企业的估值方法进行探讨,首先介绍了私募股权投资在我国生物医药领域的投资背景和特点,其次分析了生物医药企业本身的特点、不同发展阶段的特征以及估值中存在的问题,最后提出了主要的估值方法并就适用的估值阶段进行总结.     

改进的广义Nekrasov矩阵的判定条件

广义严格对角占优矩阵在科学和工程实际中有着广泛的应用,因此研究其判定问题是很有必要的.根据广义Nekrasov矩阵与广义严格对角占优矩阵的等价关系,从矩阵的元素出发,通过构造递进系数,利用不等式的放缩技巧,提出了广义Nekrasov矩阵的2个判定条件,改进了近期的一些结果,并利用数值算例说明了其有效性.     

等速输送运动纱线横向振动分析的近似解法

讨论在非齐次边界条件下由端点运动激励的纱线强迫振动问题．根据生产实际中导纱器作等速横向运动的情况，应用伽辽金方法给出稳态响应的近似解，同时与运用傅立叶级数展开所得到的稳态响应的精确解通过计算与实验进行分析与比较．     

大数据分析未来三年厨卫行业走势

由于烟灶的刚需属性,预计未来广义烟机稳态零售量与目前冰箱零售量相当。由于集成灶与油烟机、燃气灶是替代关系,预计未来广义烟机中集成灶稳定占比为30%。洗碗机作为可选消费品,预计未来稳态零售量为洗衣机的一半。假设烟灶5年、集成灶10年、洗碗机15年达到稳态,预计5年后烟灶、集成灶、洗碗机整体零售量将超过5600万台,5年的年复合增速为5.6%。     

边棱绕射的三维地震模拟

本文对地震边棱绕射的三维模拟提出了一种精确、快速、简单算法.它以广义克希霍夫理论为依据,也适用于不均匀介质.克希霍夫绕射积分中的边界值和格林函数取决于动力学射线追踪.分别对每条射线同相轴进行处理,可以获得具有清楚物理解释的描述.每一射线都用均匀渐近法对克希霍夫绕射积分进行估值.该方法对阴影边界附近的接收点仍是正确的.因为计算中需要的所有参量可以从动力学射线追踪得到,所以该算法能很容易地编入三维地震射线模拟的现有软件包中.     

Measures of overall persistence and the temporal remote state

The overall persistence, Pov, has been suggested as an indicator that integrates single media half-lives and phase partitioning. However, the application of this indicator is hindered by the fact that there are different definitions of Pov and that the most common measure of Pov, the residence time at steady state, depends heavily on the release pattern. Here, different measures are compared that can be used to compute Pov from the mass of a chemical in the environment as a function of time in a dynamic multimedia model. These measures include the equivalence width, which corresponds to the residence time at steady state, the mean value of the function of mass vs time ("mean time"), and the clearance time. The temporal remote state is defined as the state of the model system long after the stop of emissions; it is independent of the release pattern of a chemical. The mean time in the temporal remote state reflects the long-term removal rate of a chemical and is used as a persistence benchmark. Correlations of the three measures of Pov to the persistence benchmark are analyzed. The maximum equivalence width, which is obtained with release to one of the media air, water, or soil, is a good approximation of the mean time in the temporal remote state. Because the maximum equivalence width is identical to the maximum residence time at steady state, the mean time in the temporal remote state can be estimated with existing steady-state models.     

圆球导热法测定粮食导热系数研究

采用圆球导热法测定了稻谷、小麦、玉米和大豆的导热系数,并对稳态时间、装样均匀性和水分迁移等影响试验准确性的因素进行了分析.结果表明,该方法测定粮食导热系数的稳定时间至少需要8～10h,通过内外球壁多个热电偶的电势差能确保装样均匀,水分含量分别为10.9%、10.1%、11.0%、6.9%的稻谷、小麦、玉米和大豆的导热系数分别为0.105 4、0.141 8、0.136 2、0.127 4 W/(m·℃),水分迁移对低水分粮食导热系数测定结果的影响可以忽略.     

粒子随机跃迁运动暂态特征的研究

非平衡环境中,粒子运动的暂态是稳态的必经阶段,为了研究暂态与稳态的关系,从随机主方程出发,利用特征根方法,以四态模型为例,讨论了粒子一维周期性随机跃迁运动的暂态特征及其特征时间,得出结论:几率随时间的演化规律由跃迁速率常数和初始条件共同决定,而到达稳态的特征时间只由跃迁速率常数决定,与初始条件无关.     

预约调度在LGVS系统任务调度中的应用

为改善LGVS系统的搬运能力和任务延误时间指标,应用服务系统任务预约的思想建立了LGVS系统调度模型,进而构造了效益矩阵C,采用指派问题的匈牙利法求解了系统调度问题。通过仿真比较,论证了预约调度效益矩阵法无论在系统稳态平均能力a,还是实体通过系统的稳态平均滞留时间w指标上,均优于传统LGVS调度方法。     

State vector model for Contherm scraped surface heat exchanger used as an enzyme reactor in wheat starch conversions

A state vector was used to represent starch gelatinization and enzymic hydrolysis in a Contherm scraped surface heat exchanger. Wheat starch was hydrolysed in both small-scale batch and pilot Contherm experiments with Termamyl 60L α-amylase (2–3 ml kg^?1 dry solids (d.s.)) at temperatures of 90, 100, 105, 108, 110 and 120°C with feed solids contents of 30, 40 and 50% (w/w). Irreversible reactions were assumed to follow first-order kinetics in a completely-mixed reactor. Steady state conditions for the various feed solids contents were obtained from the model developed and asymptotic stability of the steady state could be demonstrated. The return of the model to steady state after small temporary disturbances was shown by employing Laplacian transfer functions. DE values of 16 to 27 could be obtained under steady state conditions after a residence time of about 7 min.     

温度对薄膜包装中气体浓度和香蕉呼吸强度的影响

在设定的10、15、20、25、30℃五个温度条件下,用已测得透气系数的低密度聚乙烯薄膜(LDPE)进行香蕉的薄膜包装贮藏试验。结果表明(1)温度越低,系统达到平衡状态所需要的时间越长,反之,所需时间越短;(2)O2和CO2浓度与温度之间的关系可以用曲线方程来描述;(3)香蕉的O2吸收速率Ro和CO2释放速率Rc的自然对数值和绝对温度的倒数值之间的关系可以通过阿伦纽斯方程(Arrhenius’equation)来描述;(4)温度对果蔬呼吸强度的影响大于温度对薄膜透气性的影响。     

A study on degradation kinetics of riboflavin in green gram whole (Vigna radiata L.)

The kinetics of riboflavin degradation in green gram whole (Vigna radiata L.), as well as in pure riboflavin solutions, at initial concentrations present in green gram were studied over a temperature range of 50–120 °C (steady state temperature process). Riboflavin degradation followed first order kinetics, where the rate constant increased with an increase in the temperature. The temperature-dependence of degradation was adequately modelled by the Arrhenius equation. The degradation kinetics of riboflavin, in normal open pan cooking, pressure-cooking and a newly developed and patented fuel-efficient `Eco-cooker', were also studied (unsteady state heating process). A mathematical model, to predict the losses of riboflavin from the time–temperature data of the unsteady state heating/cooking process, has been developed using the steady state kinetic parameters obtained. The results indicate riboflavin degradation of a similar magnitude in all three modes of cooking used in the study.     

Steady and unsteady state moisture movement in particleboards

The physical parameters, such as steady state and unsteady state diffusion coefficients, of moisture movement in particleboard are very important for modelling the moisture movement process and preventing the deformation of particleboards. The methods of determination of steady state and unsteady state diffusion coefficients were studied and the results of those determined coefficients obtained. The results demonstrated that the steady state diffusion coefficients parallel to panel surface were 10–20 times as large as those perpendicular to panel surface and unsteady state diffusion coefficients parallel were 3–5 times as large as those perpendicular to panel surface in test particle-boards. This was due to the orientation of chips in the particle-boards.