An Equivalent Circuit Model for Broadband Modified Rectangular Microstrip-Fed Monopole Antenna

A new, simple equivalent circuit model for designing a multi-mode/broadband modified rectangular microstrip-fed monopole antennas using stepped cut at four corners (SCFC) method has been presented in this paper. The SCFC method is a method in which the four corners at the edges of the patch are cut for the purpose of designing the microstrip-fed monopole antenna. The design procedure of a single mode to a broadband microstrip-fed monopole antenna is explained in order to help understand more about the proposed equivalent circuit model and SCFC method. The computer simulation technology (CST) microwave studio and advanced design system (ADS) software are used to design and simulate of the proposed microstrip-fed monopole antennas and their equivalent circuit model, respectively. The operating bandwidth of the broadband antenna with \(\hbox {S}_{11}< -10\) dB, covers the operating frequency range from 0.9 to 2.6 GHZ that it is suitable for GSM (0.9 GHz), WiFi (2.4 GHz) and LTE (2.6 GHz) applications. For the purpose of validating the simulated results, the antennas prototype has been fabricated and measured. The comparison of the measurement and simulation results shows that, there is a good agreement between them.     

Sustained oscillations in MIMO nonlinear systems through limit cycle shaping

This paper studies on generating periodic behaviors through shaping stable limit cycles in multiple‐input‐multiple‐output nonlinear systems. For this purpose, first, limit cycles are shaped with respect to the desired sustained oscillations of the system's outputs. Then, the Lyapunov analyses, which are appropriate for stability analysis of invariant sets, are employed to design the control law and conclude the asymptotic convergence toward the predefined limit cycles. The problem is studied in two cases. In the first case, some assumptions in the mathematical model are assumed that leads to simplification in the design procedure. In the second case, the design procedure is discussed in more general cases. Finally, the validity and performance of the proposed method for shaping limit cycles with different geometric shapes are illustrated by computer simulations for practical and numerical examples.     

A wideband stepped-impedance rectangular-ring resonator bandpass filter with multiple notched bands

A configuration of wideband bandpass filter (BPF) with multiple notched bands is presented. Proposed BPF is based on stepped-impedance resonator. By utilising dual stepped-impedance resonators in folded topology a rectangular-ring resonator is formed. Two notched bands in the passband are achieved without using asymmetrical coupled lines. In other words, the filter configuration is capable of producing notched bands. It should be noted that additional information on filter performance and design is presented. Measurement results are presented to approve propounded filter characteristics. The measured passband of the second proposed filter is from 3.68 to 10.2 GHz with insertion loss of –1.76 dB in the first passband at the centre frequency of 4.45 GHz. The measured notched band frequencies are about 5.45 and 7.95 GHz with rejection of –21.77 and –20.82 dB, respectively. The return loss in the passband is better than –11.4 dB.     

Characteristic Drying Curves of Cocoa Beans

ABSTRACT

The characteristic drying curves of cocoa beans are determined by using a tunnel drier where conditioned air passes a single cocoa berm suspended from an electronic balance in the test section. Weight loss, and temperatures of air, testa and nib of the cocoa bean is monitored on personal computers. The nornmalised drying rate versus the normalised moisture content is regressed by least square method to fit a new polynomial model for the penetration falling rate period and a linear model for the regular regime falling rate period. It can be concluded that there are three drying periods for cocoa beans namely the constant drying rate period, the penetration falling rate period and the regular regime falling rate period. The polynomial model estimates the penetration period quite well whereas the linear model estimates the regular regime quite well as well. There is no observable influence of relative humidity and air temperature on the characteristic drying curve of cocoa beans. However, the air velocity seems to have some influence on the curve.     

云计算的七个最佳建议

如果您是一位负责为企业实施云计算的CIO、业务分析师或项目经理,请在实施之前阅读以下提示。工作十年以上的人都明白,经济繁荣期过后必然会经历市场调整,而经济下滑会抑制创新投资。因此,云计算进入了每个人的考虑范围,也成了会议讨论的主题——它能降低成本,从有限的IT和开发资源中获取强大的可扩展性和自治性。     

Migration Issues and Strategies for Token Ring

This article considers the problems caused by ever increasing traffic on Token Ring LANs. It shows how the new IEEE 802.5 standard for DTR addresses this problem, outlining scenarios and providing a migration strategy for evolving networks, using this new standard. © 1997 John Wiley & Sons, Ltd.     

Late Jurassic Safer Salt Member in the Al-Jawf sub-basin of NW Sabatayn Basin,Yemen: geochemical evaluation of organic-rich oil-source rock potential

Late Jurassic Safer shales in the Al-Jawf sub-basin are analyzed to evaluate the organic matter input, depositional conditions and petroleum generation potential. The shales have high organic matter, with TOC values of 1.0-13.5% and they contain predominantly Types II and III kerogen, referring to mainly oil- and gas-prone. These kerogens are indicative for dominate marine algal component and some terrestrial organic matter input as indicated from biomarkers. Moreover, the presence of the gammacerane also confirmed a high salinity stratification condition and suggests that the dominate Type II kerogen is rich-sulphur kerogen (Type II-S). The vitrinite reflectance (VRo%) and Rock-Eval pyrolysis T_max data indicate that the analyzed shales are immature.     

Arch growth after staged repair of interrupted aortic arch using carotid artery interposition

BACKGROUND: Between 1980 and 1990, our practice was to perform carotid artery interposition as part of a staged repair of interrupted aortic arch with various associated cardiac defects. METHODS: This procedure was used in 16 patients with IAA type B. The median age at operation was 4.5 days and the median weight, 3.2 kg. Ten of the patients had an associated ventricular septal defect. Six more had complex anatomy. There were two death at carotid interposition, two interim deaths, and two deaths after intracardiac repair. Preoperative echocardiographic and angiographic studies were compared with postoperative studies in 11 survivors of arch repair to assess sequential growth of the interposed carotid artery. Measurements of the carotid artery were normalized to the descending aorta. RESULTS: Preoperatively, the left carotid artery had a median diameter of 3.7 mm and was 42.9% of the descending aortic diameter. Postoperative studies performed at a median age of 5.7 months disclosed that the interposed carotid artery had grown to a median diameter of 7.0 mm and was 69.6% of the diameter of the descending aorta (normal > or = 81%). On follow-up at a median time of 4 years, 6 of 9 patients have no gradient by blood pressure measurements or echocardiographic Doppler studies, and 3 have modest gradients. No patient has required revision of the arch repair. CONCLUSIONS: Survival is good after carotid artery interposition for interrupted aortic arch and growth of the carotid artery approaches that of a normal arch. Carotid artery interposition is a viable alternative for repair of this lesion should primary definitive repair not be feasible.     

Analysis of Ordered Categorical Data Using Expected Loss Minimization

Robust design is a strong method for the quality improvement of processes (or products). Two main techniques for data analysis in robust design process are the S/N ratio technique and accumulation analysis developed by Taguchi. Accumulation analysis is developed for the study of ordered categorical data. In this article, the current techniques are studied. Then, a new method that is more accurate than other methods is developed and introduced. In the next phase, an example from literature solved by the methods and the new method's optimality against other methods is shown.