硅压力传感器的可靠性试验方法及失效分析

通过对一种特定结构的硅压力传感器进行动态综合应力寿命试验 ,探讨了硅压力传感器的可靠性实验方法 ;并对失效样品进行了解剖分析 ,研究了它在温度、电压和压力共同作用下的失效机理 ,分析了产品设计、工艺与可靠性的关系 ,提出了相应的改进措施。     

一种可用于军事领域上的压力光纤传感器

介绍了压力光纤传感器的原理 ,解决了光纤加工、耦合、排除干扰及降低功耗等一系列的问题。现场测试表明 :该传感器应用于军事领域是切实可行的     

带锥敏感薄膜形变特性有限元仿真

在一种新的基于真空二极管原理的场发射压力传感器中 ,阴极发射尖锥体和敏感薄膜制备于同一硅片上 ,从而简化了传感器的封装工艺 ,但因此可能导致传感器灵敏度的减小。利用有限元仿真技术 ,计算了在外部压力作用下 ,几何形状比较复杂的带尖锥体敏感薄膜的横向挠度形变特性。计算结果表明 ,与不带尖锥体的敏感薄膜相比较 ,带尖锥体敏感薄膜在额定外部静压力作用下的最大横向挠度的减小量小于 0 .4% ,因此对传感器灵敏度的影响可以忽略不计     

压力传感器准静态“绝对校准”

介绍了传感器准静态校准的意义及落锤动标装置的工作原理 ,阐明了传感器准静态“绝对校准”的定义及方法 ,按照传感器的压力量程 ,设计了相关模型段的重锤———油缸组件 ,根据实验数据建立了各压力段的“绝对校准”模型 ,并通过实验验证了模型的可行性     

旋耕刀传感器的研究

设计了一种供旋耕刀测力用的延伸八角环传感器。该传感器具有良好的线性、较高的灵敏度及较小的滞后现象 ;各被测参数间的交互影响很小 ,可以忽略。     

正弦压力发生器在传感器动态校准中的应用

在介绍正弦压力发生器工作原理的基础上 ,讨论了在应用正弦压力发生器校准传感器动态性能时应用系统的组成和功能。同时 ,给出了采用正弦压力发生器校准传感器动态特性的两个实例。校准结果表明 :这两个传感器分别属于一阶和二阶模型 ,所得的参数模型在幅频和相频特性两方面都与实验结果一致     

Gröbner bases with respect to several orderings and multivariable dimension polynomials

Let D=K[X]$D=K\left[X\right]$ be a ring of Ore polynomials over a field K$K$ and let a partition of the set of indeterminates into p$p$ disjoint subsets be fixed. Considering D$D$ as a filtered ring with the natural p$p$-dimensional filtration, we introduce a special type of reduction in a free D$D$-module and develop the corresponding Gröbner basis technique (in particular, we obtain a generalization of the Buchberger Algorithm). Using such a modification of the Gröbner basis method, we prove the existence of a Hilbert-type dimension polynomial in p$p$ variables associated with a finitely generated filtered D$D$-module, give a method of computation and describe invariants of such a polynomial. The results obtained are applied in differential algebra where the classical theorems on differential dimension polynomials are generalized to the case of differential structures with several basic sets of derivation operators.     

Indicators for choosing an optimal mix of major working postures

North American workers usually stand while working, and prolonged standing is associated with discomfort and cardiovascular problems. Since prolonged sitting is also associated with health problems, and standing postures differ as to mobility and access to seating, it is desirable to identify an optimal mix of postures. As a step towards this identification, it is desirable to develop indicators of potential health effects that respond to changes in work requirements. We observed 65 subjects who usually stood at work, in four types of workplaces. Pressure-pain threshold (PPT) recorded on the plantar surface was used as an indicator of discomfort and arterial blood pressure was used as an indicator of cardiovascular effects. PPT after work was significantly lower than that before work. Sitting for even a small part of the day appeared to be protective. The effects of static vs. dynamic work on PPT and arterial blood pressure may differ.     

单苯环氯取代指数法预测二噁类化合物PCDDs的正辛醇/水分配系数

采用单苯环氯取代指数作为氯代二苯并二口恶口英类化合物 (PCDDs)的分子结构描述符 ,通过正向逐步线性回归方法建立了PCDDs的logKow与分子结构描述符之间的定量关系模型。与文献报道的MOD模型相比 ,该模型不仅具有显著的相关性 (n =43,Radj=0 898,SE =0 195 ,在α =0 0 5时 ,F =2 0 45 5 ,p =0 0 0 0 0 ) ,而且对于分子结构具有更好的区分能力。利用建立的模型 ,对没有logKow文献值的其他 33种PCDDs化合物给出了预测值     

涤纶长丝纺丝组件更换周期探索

通过生产实践和统计分析 ,提出涤纶长丝纺丝组件的使用周期可从原 3个月延长至 5～ 6个月。生产不同品种组件使用周期可通过上机试验来确认