Non-invasive headspace measurement for characterizing oxygen-scavenging in polymers

A non-invasive headspace analysis method to measure rate and amount of oxygen uptake in oxygen-scavenging polymers is presented. Oxygen uptake data for metal-catalyzed poly(1,4-butadiene) at 30 °C are provided to illustrate the method. These data were obtained by measuring oxygen headspace concentration above the scavenging polymer with an OxySense^® 200T non-invasive oxygen sensor, and, for comparison, oxygen uptake was measured with an analytical balance. Excellent agreement was observed between these two independent experiments.     

Synthesis,extraction, and adsorption properties of calix[4]arene‐poly(ethylene‐glycol) crosslinked polymer

Novel calix[4]arene‐poly(ethylene glycol) crosslinked polymer (CCP) has been synthesized by the polycondensation reaction between a p‐tert‐butylcalix[4]arene derivative and dihydroxyl capped poly(ethylene glycol) (DHPEG, M_n = 1000) catalyzed by neodymium tosylate. The hydrogel, consisted of 66.9% water and 33.1% CCP, can selectively extract aromatic organic molecules from aqueous solution according to the diameter of the guest molecules, which infers that the diameter of the calix[4]arene cavity is about 5.4 Å and the conformation of calix[4]arene units altered from cone conformation to 1,3‐alternate conformation during the polycondensation reaction. Furthermore, CCP can also adsorb naphthalene from gas phase, showing much higher capacity than active carbon does, which may have some potential applications in the field of separation and environment protection. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Dual band-notched ultra-wideband microstrip antenna using asymmetrical spurlines

A simple and novel ultra-wideband microstrip-fed antenna with dual band-notched characteristic is presented. By etching a pair of asymmetrical spurlines on the feedline, two notched bands of 600 MHz (3.95? 4.55 GHz) and 650 MHz (5.35?6.0 GHz) are achieved. Measured results show that this antenna operates from 2.5 to 12.0 GHz for voltage standing wave ratio less than 2, except two frequency notched bands of 3.95?4.55 GHz and 5.35?6.0 GHz. Moreover, this antenna has good omnidirectional radiation patterns in the H-plane.     

ROI-based Watermarking Scheme for JPEG 2000

A new region of interest (ROI)-based watermarking method for JPEG 2000 is presented. The watermark is embedded into the host image based on the characteristics of the ROI to protect rights to the images. This scheme integrates the watermarking process with JPEG 2000 compression procedures. Experimental results have demonstrated that the proposed watermark technique successfully survives JPEG 2000 compression, progressive transmission, and principal attacks.     

Enclosing all solutions of two-point boundary value problems for ODEs

The two-point boundary value problem (TPBVP) occurs in a wide variety of problems in engineering and science, including the modeling of chemical reactions, heat transfer, and diffusion, and the solution of optimal control problems. A TPBVP may have no solution, a single solution, or multiple solutions. A new strategy is presented for reliably locating all solutions of a TPBVP. The method determines narrow enclosures of all solutions that occur within a specified search interval. Key features of the method are the use of a new solver for parametric ODEs, which is used to produce guaranteed bounds on the solutions of nonlinear dynamic systems with interval-valued parameters and initial states, and the use of a constraint propagation strategy on the Taylor models used to represent the solutions of the dynamic system. Numerical experiments demonstrate the use and computational efficiency of the method.     

广州电视塔及广州电视台设计

信基建筑事务所(Information Based Architecture)是由Mark Hemel和Barbara Kuit于1998年在伦敦成立的,2002年办公地点迁往阿姆斯特丹.……     

增强大学生职业规划效果的宏观对策

针对目前大学生职业规划效果不佳的现状，分析了导致大学生职业规划效果不佳的原因，提出了增强大学生职业规划效果的宏观对策。     

On the lateral response of regular highrise frames

This paper introduces a simple approach for the study of the structural phenomena associated with the lateral response of regular highrise frames. The concept is based upon the assumption that the structure is composed of imaginary modules that fit within the actual bays of the framework, and that all imaginary modules deform through similar shapes by formation of points of inflexion at similar locations. The imaginary modules of a story are combined to form an equivalent ‘basic module’ that possesses the same structural characteristics as the corresponding story level subframe. The concept is used to establish an analogy between the lateral response of highrise structures and discretized Timoshenko beam-columns with similar boundary conditions. The properties of the basic module have been employed in conjunction with the techniques of finite difference calculus to derive the governing equation of motion of a regular discretized Timoshenko beam under uniform compression. The use of the concept is further utilized to obtain a number of closed form formulae for the initial design of multistory structures. These include expressions for the determination of the natural frequencies, the P-delta effects, as well as the critical buckling loads of regular multistory frames. Numerical examples have been provided to demonstrate the applications and the simplicity of the proposed solutions.