Dual-frequency operation of CPW-fed antenna controlled by pindiodes

pin diode control is used to obtain a dual-band operation of a capacitively coupled patch antenna fed by a coplanar waveguide (CPW). The beam-lead pin diodes are inserted in the excitation slot and reduce the coupling length of the slot in their ON state. The frequency ratio of the two operating frequencies is 1.22 at 4.0 GHz. Details of the antenna design and experimental results are presented and discussed     

MMPP models for multimedia traffic

The paper presents a study on the use of Markov‐Modulated Poisson Processes (MMPP's) for characterizing multimedia traffic with short‐term and long‐term correlation. The applicability of the 2‐state MMPP and a refined moment‐based parameter‐matching technique to model an arbitrary ATM traffic stream in evaluating its queueing performance are examined by simulation. Following a discussion on the limitation of the 2‐state MMPP model, a model using a superposition of N homogeneous 2‐state MMPP to characterize bursty multimedia traffic is presented. The proposed model requires only five parameters which can be estimated from the samples of the traffic counting process by using a pdf‐based matching technique. The introduced pdf‐based parameter‐matching procedure uses the probability density function of the arrival rate and the IDC curve of the traffic samples. An approximation for the probability of loss in MMPP/D/1 queues is also obtained. The versatility and accuracy of the proposed model to characterize bursty multimedia traffic are shown by several case studies and test results. This revised version was published online in June 2006 with corrections to the Cover Date.     

烧结厂节能降耗的措施

为降低烧结工序能耗，广钢烧结厂采取了加强能源管理以及技术创新和改造等有效手段，取得了明显效果，为降低成本、增加效益创造了有利条件。并提出了进一步节能的方向和措施。     

Cooking procedures for direct consumption of whole soybeans

The purpose of this research was to determine adequate conditions for the preparation of soybeans at home level. In accordance with the results, soaking the soybeans for eight hours in a 0.25% bicarbonate solution, gives the appropriate hydration to the soybeans, which can then be easily cooked. Boiling them at atmospheric pressure during 20 minutes was required to destroy 80% of the soybeans antitrypsin activity, and a high PER was also obtained. Nevertheless, the soybeans texture was not satisfactory; therefore, longer boiling periods were tested so as to establish the most suitable time needed to achieve a softness similar to that of common beans as usually consumed. Softness was measured instrumentally, and the optimal conditions found were: 40 min boiling after 8 hr soaking in a 0.25% bicarbonate solution. Under these conditions, the PER and NPU values increased 18% and 33%, respectively, with respect to those of the casein PER and NPU. It is concluded that with this procedure, large amounts of protein can become available at an equivalent price to US$0.40/kg ($80.00/kg).     

Application of headspace analysis to the study of aroma compounds-lipids interactions

Taking into account interactions between aroma compounds and food components is necessary to better manage the flavoring of food products. These interactions occur at a molecular level and reflect changes, at a macroscopic level, in thermodynamic equilibria, such as solubility or volatility. The rate of transfer of an aroma compound from the liquid to the vapor phase can be affected as well. The behavior of aroma compounds in water and lipid solutions was studied in two complementary ways, a thermodynamic and a kinetic approach (head-space analysis). The transfer rate of volatiles at the liquid-water interface does not only depend on the hydrophobicity of the aroma compounds. Vapor-liquid partition and activity coefficients show the presence of solute-solvent interactions. The Gibbs free energy values indicate their physicochemical nature.     

High-Speed Visible Light Communications Using Multiple-Resonant Equalization

White light-emitting diodes (LEDs) are becoming widespread in commercial lighting applications, and there are predictions that they will be in common use in domestic applications in the future. There is also growing interest in using these devices for both illumination and communications. One of the major challenges in visible light communications is the low modulation bandwidth (BW) available from devices, which is typically several megahertz. In this letter, we describe a link that uses 16 LEDs which are modulated using a resonant driving technique, creating an overall BW of 25 MHz. This is used to implement a 40-Mb/s nonreturn-to-zero on-off keying link which operates at low error rates, and also provides illumination at levels sufficient for a standard office environment.     

新型柱锤强夯法处理地基的检测分析

通过对几个工程检测实例分析及验算,阐述了在新型柱锤强夯(置换)法处理地基检测时,应从点、面上区别对待,分别进行统计,以体现处理后岩土层实际的物理、力学性能。