高弹性顶杆式带锯机张紧系统时滞确定的计算机仿真研究(2)

本文通过对高弹性顶杆式带锯机张紧系统时滞状态方程的分析，得出了确定带锯机张紧系统时滞的有效方法。并运用MATLAB软件进行了计算机仿真，为实际理论研究奠定了初步基础。所提供的方法对于今后进行该方面问题的研究提供了一种新的思路。     

带锯机高弹性顶杆式张紧系统系统辨识的研究

本文通过对东北林业大学机电工程学院木工机械实验室的MJ317型细木工带锯机振动情况进行计算机采集数据，并对其分析，运用MATLAB系统辨识工具箱对其模型特征参数进行了仿真分析，为今后有关研究奠定了基础。     

带锯机高弹性顶杆式张紧系统系统辩识的研究

本文通过对东北林业大学机电工程学院木工机械实验室的MJ317型细木工带锯机振动情况进行计算机采集数据,并对其分析,运用MATLAB系统辩识工具箱对其模型特征参数进行了仿真分析,为今后有关研究奠定了基础。     

弹簧刚度对木工带锯机弹性挺杆式张紧系统反应时滞影响的实验研究

利用改进设计的弹性挺杆式张紧系统取代原有的杠杆压砣式张紧系统,在空载的情况下,进行了关键部位振动的测试,获得了弹簧刚度对木工带锯机弹性挺杆式张紧系统反应时滞影响的规律     

带锯机杠杆压砣式张紧系统振动的分析

本文通过对带锯机杠杆压砣式张紧系统振动的实验，运用DASP6．53分析系统进行了分析，为改善带锯机的动态特性提供了依据。     

带锯机张紧杠杆位置与张紧力关系的再研究

本文主要通过理论分析和张紧力模拟系统验证，来研究在重锤杠杆式张紧机构中，杠杆空间位置状态与张紧力的变化关系。首先建立了重锤杠杆式张紧机构的张紧力数学模型。通过数学模型的分析可知，杠杆位置在水平以下向水平位置移动的过程中张紧力呈增大趋势。并在水平位置处张紧力达到最大。在水平位置以上移动时张紧力呈逐渐减小的趋势。然后进行了实验，实验结果证明了理论分析是正确的。从而为合理确定重锤杠杆的初始位置，提高切削精度和加工质量。减小切削损失提供了理论依据。     

带锯机板式弹簧张紧系统锯条横向振动的研究

本文运用先进的DASP6．53型大容量数据采集分析测试系统测试并分析了带锯机板式弹簧张紧系统锯条的横向振动，验证了运用板式弹簧张紧系统对于减小锯条振动量具有较大的作用，从而为今后进一步开发具有实效的新型张紧系统奠定了基础。     

杠杆压砣式张紧系统数学模型的研究

本文通过对杠杆压砣式张紧系统部件工作的分析及研究，运用现代控制理论建立了经紧系统的数学模型，为今后进一步研究张紧系统的动态力学特性奠定了基础。     

张紧杠杆位置与张紧力关系的初步研究

本文初步研究了带锯机重锤式张紧机构中，杠杆的空间位置状态与张紧力的变化关系。从而正确确定杠杆位置。同时也分析了了带锯锯条长度对杠杆位置的影响。     

Development of a computer simulation model for processing food in a microwave assisted thermal sterilization (MATS) system

The microwave assisted thermal sterilization computer simulation model (MATS-CSM) was developed to improve the previous computer simulation model for the microwave assisted thermal sterilization (MATS) system. Development of the new MATS-CSM included determination of optimum heating time step, evaluation of electromagnetic field distribution and the resulting heating pattern in food, and experimental validation of heating patterns. It was determined that the minimum number of discretization that would not cause immediate divergence of the EM-heat transfer solution was 32 steps corresponding to 97 mm and 5.6 s of displacement and heating time for every step, respectively. Furthermore, this study successfully demonstrated the symmetrical electromagnetic field distribution between top and bottom microwave entry ports and a staggered electric field pattern from one cavity of the MATS to the next. In addition, MATS-CSM confirmed that incorporating heat diffusion in the simulation model reduces the difference in hot spot and cold spot temperature by 65%. It also confirmed that water circulation reduces the edge heating effect, as observed in experiments. The heating pattern generated by MATS-CSM was verified experimentally through a chemical marker method. Based on the percent areal cross section of the weighted average temperature, there were no noticeable differences between the heating zones generated by the MATS-CSM and by the chemical marker method. The percent areal cross section of the cold area 1, cold area 2, and hot area by MATS-CSM were 35%, 25%, and 40%, respectively, and the cold area 1, cold area 2, and hot area by chemical marker method were 35%, 30%, and 35%, respectively.     

往复式锯材剖分锯的控制系统研究

针对目前往复式锯材剖分锯控制系统由继电器逻辑方式控制时,系统故障率高,检修周期长,而由数控系统控制价格昂贵等问题,设计了一种由PLC控制的往复式锯材剖分锯控制系统,详细介绍了系统硬件、软件的设计。通过对剖分锯动作过程的分析,确定整机的动作顺序要求及操作面板的功能要求,完成电器元件的选型、整机电气原理图的设计、硬件选型清单的确定,该系统可实现设备自动化加工,提高生产效率,降低工人劳动强度,保证安全生产。     

A model describing the effect of temperature history on lag time for Listeria monocytogenes

A model was built to describe the influence of the temperature and the duration of pre-incubation on the lag time for regrowth of Listeria monocytogenes at low temperature. This model is consistent with the usual procedure used to calculate lag times of cultures growing under fluctuating temperatures. It also describes the effect of prolonged starvation conditions on the regrowth lag time and takes into account the influence of the physiological state of inocula in predictive models.