Principles of pressure transducer function and sources of error in clinical use

The invasive measurement of physiological pressures is a common requirement in anaesthesia and intensive care medicine. From arterial blood pressure to intracranial pressure, these calculated variables give a swift graphical and numerical representation of a patient's current physiological status. This allows us to respond rapidly to conditions outside our preferred parameters and to carefully titrate treatment to target effects. These systems are, however, not infallible. An understanding of the principles of their function will promote appropriate use and an ability to recognize and react to sources of error. This article aims to furnish the reader with this level of understanding in order to inform their academic and clinical practice.     

Optimal pole assignment into specified regions and its application to rotating mechanical systems

This paper considers a pole assignment problem to cluster all poles of a closed-loop system into some specified regions by introducing the complex state for systems having an isotropic property and by using the Riccati equation. The algebraic relations for the distribution of the eigenvalues of a complex matrix are used in order to cluster the poles into specified regions, which guarantees the relative stability margin, e.g. uniform damping or uniform damping ratio. The proposed scheme is essentially a combination of the pole assignment approach and linear quadratic design, taking the advantages of both. A block modal control method—an extension of recursive pole assignment—is also developed for the vibration control of rotating systems by clustering the forward and backward modes in order. Vibration control simulations with an isotropic rotor—bearing system, a magnetic bearing system and a rotating circular disc are treated in order to demonstrate the advantages of the proposed method.     

Damping characteristics of bone‐to‐implant interface; A clinical study with the Periotest® device.

The Periotest® device was used to evaluate the damping characteristics of different bone‐to‐implant interfaces of Brånemark implants. Implant and abutment lengths were found to have a significant influence on Periotest value (PTV). There was no statistical difference between PTVs of implants located in the anterior and posterior areas of the same jaw at abutment connection. No differences were found between PTVs of standard and self‐tapping implants. PTVs at abutment connection were highly influenced by the bone quality. The contact with two corticals, one at each extremity of the implant, was of a greater influence in the maxillary than in the mandibular jaw, indicating a firmer anchorage between the bicortical implants and the surrounding bone. A proaressive decrease of PTVs over time was observed, significant up to 5 years of loading.     

Embedded NiTi Wires for Improved Dynamic Thermomechanical Performance of Silicone Elastomers

The extraordinary properties of shape memory NiTi alloy are combined with the inherent viscoelastic behavior of a silicon elastomer. NiTi wires are incorporated in a silicon elastomer matrix. Benefits include features as electrical/thermal conductivity, reinforcement along with enhanced damping performance and flexibility. To gain more insight of this composite, a comprehensive dynamic thermomechanical analysis is performed and the temperature- as well as frequency-dependent storage modulus and the mechanical loss factor are obtained. The analyses are realized for the composite and single components. Moreover, the models to express the examined properties and their temperature along with the frequency dependencies are also presented.     

应用Flash MX制作阻尼振动动画

分析了阻尼振动的运动方程,介绍利用Flash MX制作阻尼振动演示动画的思路和过程。动画演示使学生更形象、直观地接受阻尼振动的概念。     

拉曼耦合J-C模型中原子与光场间的量子纠缠

研究了拉曼耦合J—C模型中存在位相损耗时，原子与光场间的量子纠缠性质，讨论了位相损耗、光场平均光子数和不同的原子初态对系统纠缠特性的影响．结果表明：由于位相损耗的存在，使系统的纠缠随时间演化而减弱，但并不改变其演化的周期性；当光场较强时，其纠缠明显减弱；原子初始所处的状态对系统的纠缠性质也会产生明显的影响．     

粘弹性阻尼材料中互穿聚合物网络技术的应用

阐述了粘弹性材料在振动波作用下的阻尼机理，指出声波法和模量法的统一性。综述了互穿聚合物网络技术要点，并解释相分离体系宽玻璃化转变区间的形成机理；介绍了互穿聚合和网络技术形成的新途径及梯度互穿聚合物网络技术要点。     

氢化丁腈橡胶/受阻酚阻尼复合材料的制备与结构

将受阻酚AO-80加入氢化丁腈橡胶(HNBR)中,成功制备了氢化丁腈橡胶/受阻酚阻尼复合材料。利用差示扫描量热分析（DSC）、X射线衍射分析（XRD）、动态力学分析（DMA）、扫描电子显微镜（SEM）等测试手段对该复合材料进行了表征。测试结果表明：随着AO-80含量的增加,复合材料的阻尼因子逐渐增大,峰值对应温度逐渐移动至室温附近;在氢化丁腈橡胶（HNBR）内部,AO-80以无定形微球颗粒和无定形聚集体两种形式存在,以这两种形式存在的AO-80均可以利用氢键作用提高HNBR的阻尼性能。