螺旋焊管内涂层涂敷挥发份的清除

针对大口径螺旋焊管内涂层涂敷作业时，钢管内残留的涂料挥发份如何清除的问题，介绍了一种自行设计制造的内涂层涂敷挥发份吹除装置。     

具有除草活性的双膦酸衍生物的研究动态

许多含双膦酸结构单元的化合物都显示了良好的除草活性,本文对这类化合物的结构特点、生物活性以及相关的研究动态进行了归纳和概述。     

High-resolution electron microscopy of the twinning and intergrowth in Ca4Al6SO16 and Ca3SrAl6SO16

The microstructures of unhydrated calcium aluminosulphate Ca₄Al₆SO₁₆ and Ca₃SrAl₆SO₁₆ have been studied by high-resolution electron microscopy (HREM). The results showed that twinning and twinned slabs could be introduced taking the [1 1 2] direction as the twin axis so that it seems to be coincident with the law of twinning formed in body-centred cubic structures. A previously reported superlattice with a repeat period twice that of the fundamental structure along the 〈1 1 0〉 direction has also been found in both matrix and twin variants. The close intergrowth of Ca₃SrAl₆SO₁₆ and another phase, possibly Sr₃Al₂O₆ existing as an inclusion between these two twin variants, was determined and clearly revealed by electron diffraction and HREM images. The coherent interphase boundaries and orientation relationship between them can also be deduced.     

A Note on PIN Polynomials and PRIN Rational Functions

This brief presents a necessary and sufficient condition for testing positive, real, imaginary, and negative rational functions. A related term, the positive, imaginary, and negative polynomial, is defined and two necessary and sufficient conditions for testing it are given.     

Effect of refraction on optical microscopic measurement of internal blood-vessel diameter and its correction

In optical microscopic measurement of internal blood-vessel diameters, the effect of refraction must be taken into account to ensure accuracy of the result. This effect is discussed and an analytical correction formula derived. Phantom blood vessels with known internal and external diameters were used to test the validity of the correction formula. The errors obtained prior to correction were reduced significantly after correction.     

End-to-End QoS for Video Delivery Over Wireless Internet

Providing end-to-end quality of service (QoS) support is essential for video delivery over the next-generation wireless Internet. We address several key elements in the end-to-end QoS support, including scalable video representation, network-aware end system, and network QoS provisioning. There are generally two approaches in QoS support: the network-centric and the end-system centric solutions. The fundamental problem in a network-centric solution is how to map QoS criterion at different layers respectively, and optimize total quality across these layers. We first present the general framework of a cross-layer network-centric solution, and then describe the recent advances in network modeling, QoS mapping, and QoS adaptation. The key targets in end-system centric approach are network adaptation and media adaptation. We present a general framework of the end-system centric solution and investigate the recent developments. Specifically, for network adaptation, we review the available bandwidth estimation and efficient video transport protocol; for media adaptation , we describe the advances in error control, power control, and corresponding bit allocation. Finally, we highlight several advanced research directions.     

反渗透膜仓用韧性环氧树脂基体研究

工业上广泛使用反渗透膜仓制备高纯水,为了用玻璃钢替代不锈钢,研究了一种适合湿法缠绕的反渗透膜仓用韧性环氧基体。在配方中采用液体酸酐固化剂甲基四氢邻苯二甲酸酐和高效活性增韧剂,对树脂基体和复合材料力学性能及耐水性能的研究表明该树脂基体具有许多优良性能,如拉伸强度≥86.2MPa,断裂延伸率≥5.2%,弯曲强度≥139MPa,制得膜仓爆破时纤维强度转化率高达88.7%,耐疲劳达10万次而无损伤。此外,配方体系室温下粘度为0.35～0.4Pa·s,适用期≥8h,室温下在水中浸泡180d后吸水率低于0.5%,同不锈钢相比成本降低1/2。实验结果表明,该韧性环氧基体完全适用于反渗透膜仓使用。     

掺杂VO2的特性、制备方法及应用

VO2在68℃时发生从低温的单斜相向高温四方相转变，同时伴随着光、电、磁性能的突变。通过掺入其它杂质元素，能有效改变其相变温度和光、电性能，这些优异特性使其具有更好的应用前案。本文综述了掺杂的原理，掺杂对VO2相变影响、常用的掺杂方法及目前的应用情况，这对其进一步的研发应用具有重要的意义。