Estimation of energy expenditure in a work environment: Comparison of accelerometry and oxygen consumption/heart rate regression

The aim of this study was to compare estimation of energy expenditure (EE) in working environments, either from accelerometry or from an individual oxygen consumption/heart rate ([Vdot]O₂/HR) regression curve. The study participants were 46 volunteer workers aged 27±6 years old. A significant correlation between EE predicted by the [Vdot]O₂/HR curve and the accelerometer was observed (r=0.78, p <0.01). However, more disparities were observed between the two methods when the mean job intensity was not within 16% and 23% higher than resting HR. The accelerometer overestimated by a mean of 34.4% the prediction by [Vdot]O₂/HR regression if the intensity of the task was lower than a total of 1000 kcal/shift and underestimated the prediction by a mean of –24.9% if EE estimation of the work shift was higher than a total of 1500 kcal/shift. Despite a high correlation between both methods in the whole group, EE evaluated by accelerometry does not correspond to EE predicted by the [Vdot]O₂/HR regression curves when evaluated individually.     

FPGA的动力电池检测系统研究

为提高动力电池使用效率,提出了一种基于FPGA的动力电池检测系统的设计方案.采用AD转换芯片实现对电池电压、电流的采集,数字温度传感器对温度进行采集,再通过软件实现对数据的处理和实时显示.系统运行稳定,数据处理能力强,集成度高,易于扩展.     

载流导体的二维温度场的分析

为分析机电设备导体中电流引起的热分布问题,建立了机电设备的简化有限元模型,对导体进行了自适应网格划分,采用有限元方法求解热导微分方程,得到导体中热分布情况,可以估算导体的形状和尺寸,为机电设备选择合适的导体提供了一种有效的设计方法。     

叶片类零件检测方法的试验研究

研究了交流电磁场信号对叶片裂纹影响的方式和规律,分析和找出了缺陷与交流电磁场信号响应特征之间的关系,提出了叶片表面采用交流电磁场检测技术的原理、方法.通过采用交流电磁场检测技术检测证实,在工程检测中有一定的实际意义.     

Interplay Between Wetting and Phase Behavior in Binary Polymer Films and Wedges: Monte Carlo Simulations and Mean Field Calculations

Confining a binary mixture, one can profoundly alter its miscibility behavior. The qualitative features of miscibility in confined geometry are ratheruniversal and shared by polymer mixtures as well as small molecules, but the unmixing transition in the bulk and the wetting transition are typically well separated in polymer blends. The interplay between wetting and miscibility of a symmetric polymer mixture via large-scale Monte Carlo simulations in the framework of the bond fluctuation model and via numerical self–consistent field calculations is studied. The film surfaces interact with the monomers via short ranged potentials, and the wetting transition of the semi–infinite system is of first order. It can be accurately located in the simulations by measuring the surface and interface tensions and using Young’s equation. If both surfaces in a film attract the same component, capillary condensation occurs and the critical point is close to the critical point of the bulk. If surfaces attract different components, an interface localization/delocalization occurs which gives rise to phase diagrams with two critical points in the vicinity of the pre-wetting critical point of the semi–infinite system. The crossover between these two types of phase diagrams as a function of the surface field asymmetry is studied. The dependence of the phase diagram on the film thickness Δ for antisymmetric surface fields is investigated. Upon decreasing the film thickness, the two critical points approach the symmetry axis of the phase diagram, and below a certain thickness Δ_tri, there remains only a single critical point at the symmetric composition. This corresponds to a second-order interface localization/delocalization transition even though the wetting transition is of first order. At a specific film thickness, Δ_tri, tricritical behavior is found. The behavior of antisymmetric films is compared with the phase behavior in an antisymmetric double wedge. While the former is the analog of the wetting transition of a planar surface, the latter is related to the filling behavior of a single wedge. Evidence for a second-order interface localization/delocalization transition in an antisymmetric double wedge is presented, and its unconventional critical behavior is related to the predictions of Parry et al. (Phys. Rev. Lett. 83:5535 (1999)) for wedge filling. The critical behavior differs from the Ising universality class and is characterized by strong anisotropic fluctuations.Invited paper presented at the Fifteenth Symposium on Thermophysical Properties, June 022–27, 2003, Boulder, Colorado, U.S.A.     

多元回归分析在电热式平板硫化机热板温度场中的应用

分析电热平板硫化机热板温差大的主要影响因素,重点研究热源分布情况对温差的影响.以400×400电热平板硫化机为例,应用多元回归的二次响应曲面模型及其子模型,对热源间距(电热管间距)与热板表面最大温差之间的函数关系进行预测,检验并分析预测结果(拟合曲线)的可靠程度,从而得出较合理的数学模型,即完整二次响应曲面模型.此模型可为工程设计提供参考依据.     

Development of a Reconfigurable Platform for Manufacturing Equipment Control

In modern manufacturing equipment control area,controller is required to deliver higher computing capability for adopting advanced algorithms to meet speed and accuracy requirements,and reconfigurabilities for changing or(and)adding features or functions.This paper presents a methodology in design and implementation of a high performance and reconfigurable platform for manufacturing equipment control.This methodology is in virtue of system on a programmable chip(SoPC)technolo- gy but replacing the on-chip processor by an external high performance,floating-point digital signal processor(DSP).The appli- cation of the DSP is designed as a multi-threaded framework,which has more flexibilities than a traditional single-loop one.Fur- thermore,the field programmable gate array(FPGA)system can be reconfigured easily and quickly to meet a new requirement by dragging and dropping pre-built components in a SoPC building environment.As a result,the controller platform is more recon- figurable in terms of algorithms and functions.This platform is implemented in a 3-axis milling machine control and the result indicates that the design and implementation presented in this paper is feasible.     

ZF12-145(L)气体绝缘金属封闭开关设备断路器

介绍了ZF12-145（L）三相共箱式气体绝缘金属封闭开关设备断路器的技术参数、性能、灭弧室的计算分析和主要特点.     

基于三角形滤波卷积核的快速线积分卷积算法

基于纹理的线积分卷积(LIC)方法,能连续细致、动画地表示2D矢量大小和方向,但卷积计算极其耗时。针对这个问题实现了基于常数滤波卷积核的快速线积分卷积算法,提出并论证了基于三角形滤波卷积核的快速线积分卷积算法,对于实际矢量场,上述两种方法均将运算速度提高了一个数量级,而基于三角形滤波卷积核的快速线积分卷积算法的结果使图像更加平滑。     

感应加热高强度包装钢带生产线及工艺技术特点

介绍了唐山钢铁集团有限公司建的国内第一条感应加热高强度包装钢带生产线主要设备及技术工艺特点。