Time difference amplifier design with improved performance parameters

2012 ◽  
Vol 48 (10) ◽  
pp. 562 ◽  
Author(s):  
A.N.M. Alahmadi ◽  
G. Russell ◽  
A. Yakovlev
Author(s):  
Pekka Salonen ◽  
Lauri Syda¨nheimo ◽  
Mikko Keskilammi

Antennas play a paramount role today’s communication centered market place. Recently the demands for miniaturization of electronic devices have increased rapidly in which a miniaturization of integrated antennas has confronted the same development. However, antennas and especially the performance parameters of antennas obey physical laws in which the electrical dimensions of an antenna have a major effect on these parameters such as voltage standing wave ratio (SWR) and radiation efficiency. Recently, a new, multidisciplinary field of study called “Electromagnetic BandGap” (EBG) structures have been developed. An EBG structure forms a lattice whose period determines its resonant frequency i.e. the range of frequencies where the stop band exists for transmission of microwave signals. Antennas physical dimensions can be made noticeably smaller applying EBG materials. These advantages of EBG structures allow us to design smaller antennas with high radiation efficiency on high-dielectric substrates such as ceramics. This paper presents how conventional microstrip antennas can be miniaturized using EBG materials with improved performance parameters. In addition, a novel flexible antenna is presented which can be rolled up during e.g. transportation.


2014 ◽  
Vol 686 ◽  
pp. 354-358
Author(s):  
Zhong Yue Hu

This paper puts forward adaptive anti collision algorithm based on two fork tree decomposition. New search algorithm built on the basis of binary-tree algorithm, using the uniqueness of the label EPC, to estimate the distribution of label by slot allocation, the huge and complicated two fork tree is decomposed into several simple binary-tree by search the collision slots for binary-tree, so, it can simplifies the search process. The algorithm fully considers4 important performance parameters of the reader paging times, transmission delay, energy consumption and throughput label, the simulation results show that, the improved anti-collision algorithm is obviously improved performance than other two fork tree algorithm, it is more suitable for RFID anti-collision protocols.


2019 ◽  
Vol 33 (5) ◽  
pp. 395-403 ◽  
Author(s):  
Andy Kerr ◽  
Allan Clark ◽  
Valerie M. Pomeroy

Background. Recovery of the sit-to-stand (StS) movement early after stroke could be improved by targeting physical therapy at the underlying movement deficits in those people likely to respond. Aim. To compare the movement characteristics of successful and failed StS movements in people early after stroke and identify which characteristics change in people recovering their ability to perform this movement independently following rehabilitation. Methods. Muscle activity and kinematic (including center of mass, CoM) data were recorded from 91 participants (mean 35 days after stroke) performing the StS movement before (baseline), immediately after (outcome), and 3 months after (follow-up) rehabilitation. Three subgroups (never-able [n = 19], always-able [n = 51], and able-after-baseline [n = 21]) were compared at baseline with the able-after-baseline subgroup compared before and after rehabilitation. Results. The subgroups differed at baseline for quadriceps onset time ( P = .009) and forward body position when quadriceps peaked ( P = .038). Following rehabilitation, the able-after-baseline subgroup increased their forward position ( P < .001), decreased the time difference between bilateral quadriceps peaks ( P < .001) and between quadriceps and hamstrings peaks on the nonhemiplegic side ( P = .007). An improved performance in the always-able subgroup was associated with a number of baseline factors, including forward positioning ( P = .002) and time difference between peak activity of bilateral quadriceps ( P = .001). Conclusions. This neuromechanical study of StS before and after rehabilitation in a sample of people early after stroke identified the importance of temporal coupling between forward trunk movement and quadriceps and hamstrings’ activity. These findings advance the science of stroke rehabilitation by providing evidence-based therapy targets to promote recovery of the StS movement.


2021 ◽  
Vol 99 (Supplement_1) ◽  
pp. 98-99
Author(s):  
Carson M De Mille ◽  
Nicholas K Gabler

Abstract Weaned pigs are typically fed complex, highly digestible diets to maximize feed intake and weight gain as they transition into the nursery. Further, pharmacological concentrations of zinc (Zn) and copper (Cu) are commonly fed to mitigate weaning-related diarrhea and performance reductions. A 2 x 2 factorial design was utilized to determine the effect of diet complexity with or without Zn and Cu. Four-hundred and thirty-two weaned pigs were randomly allotted to 48 pens (n = 9 pigs/pens). Pens were assigned to one of four diets: 1) A high soybean meal diet (Simple), 2) Simple + ZnCu, 3) Low soybean meal diet with spray-dried plasma, casein, and oats (Complex), and 4) Complex + ZnCu. Diets were fed in two 14 d phases. For ZnCu there were 3,000 and 2,000 ppm Zn in phase 1 and 2, and 200 ppm Cu in both phases. Bodyweight and feed intake were determined in phase 1 (d 0–14) and phase 2 (d 15–28). Pen was the experimental unit and all data were analyzed by diet complexity, pharmacological minerals and their interaction. No complexity by ZnCu interaction or diet complexity effects were observed in the 28 d study. However, ZnCu increased ADG (0.23 vs. 0.16 kg/day, P &lt; 0.0001), ADFI (0.28 vs. 0.24 kg/d, P &lt; 0.0001), and GF (0.80 vs. 0.69, P &lt; 0.0001) in phase 1. In phase 2, ZnCu increased ADG by 9% (P = 0.008) and ADFI by 16% (P = 0.0001) compared to non-supplemented counterparts. Overall (0–28 d), ZnCu pigs had heavier end bodyweight (15.9 vs. 14.5 kg, P = 0.009), and greater ADFI (0.47 vs. 0.41 kg/d, P &lt; 0.0001). In conclusion, diet complexity (high levels of soybean meal versus specialized protein alternatives) did not alter nursery performance. Irrespective of diet complexity, pharmacological Zn and Cu improved performance parameters.


Author(s):  
Erhiega N. Umayah ◽  
Viranjay M. Srivastava

In this research work, a Cylindrical Surrounding Patch Antenna (CSPA) with improved performance parameters based on inset feed method compared to other feed techniques has been proposed for 1.8 GHz applications. The designed and simulated CSPA is a rotary version of an initially designed Rectangular Planar Patch Antenna (RPPA). The RPPA is mounted on a cylindrical surface with radius (r) 10 mm which is an increased curvature for better -10 dB S-parameter (S11), impedance Band Width (BW), Voltage Standing Wave Ratio (VSWR), radiation pattern, and gain. The copper radiating patch has been conformed on the surface of the grounded flexible polyimide substrate with relative permittivity (εr) 3.5 and thickness (h) 1.6 mm at normalized input impedance of 50 Ω. Results for the RPPA and the proposed CSPA have been compared with existing designs in terms of antenna size, resonant frequency (fr), return loss (S11), and gain while taking cognizance of the feeding techniques. The S11, BW, VSWR, and gain are -12.784 dB, 28 MHz, 1.8, and 4.81 dBi respectively for the rectangular planar patch antenna and -35.571 dB, 66 MHz, 1.5, and 3.74 dBi, respectively for the cylindrical surrounding patch antenna.


Author(s):  
T. Popova ◽  
E. Petkov ◽  
M. Ignatova

The aim of the work was to assess the effect of dietary inclusion of meals derived from black soldier fly (BSF) larvae on the performance and carcass composition in broilers. The trial was carried out with Ross 308 broilers divided in three groups according to the formulated diets: control, receiving standard diet, DFBSFM (receiving 5% partially defatted BSF meal), and FFBSFM (receiving 5% full fat BSF meal during the growing-finishing period, 14 to 35 days of age). The performance parameters controlled included body weight, weight gain, feed intake, feed conversion ratio, as well as the growth rate for each week of the trial. At 35 days of age, 10 broilers from each group were slaughtered and subjected to carcass analysis. The inclusion of 5% DFBSFM and FFBSFM in the diet improved performance of the broilers at the age of 21 and 35 days. The carcass weight and dressing percentage were higher in the groups receiving the insect meals. The results indicate potential of the DFBSFM and FFBSFM to alter the carcass composition of the broilers. Their inclusion in the diet of the birds tended to increase the percentage of the breast cuts, whereas the thigh muscles significantly decreased. The results of the study suggest good prospective for further research with the examined BSF meals, for their application as feed components in broiler nutrition that will not have adverse effect on the carcass composition and quality.


Author(s):  
Gertrude. F. Rempfer

Optimum performance in electron and ion imaging instruments, such as electron microscopes and probe-forming instruments, in most cases depends on a compromise either between imaging errors due to spherical and chromatic aberrations and the diffraction error or between the imaging errors and the current in the image. These compromises result in the use of very small angular apertures. Reducing the spherical and chromatic aberration coefficients would permit the use of larger apertures with resulting improved performance, granted that other problems such as incorrect operation of the instrument or spurious disturbances do not interfere. One approach to correcting aberrations which has been investigated extensively is through the use of multipole electric and magnetic fields. Another approach involves the use of foil windows. However, a practical system for correcting spherical and chromatic aberration is not yet available.Our approach to correction of spherical and chromatic aberration makes use of an electrostatic electron mirror. Early studies of the properties of electron mirrors were done by Recknagel. More recently my colleagues and I have studied the properties of the hyperbolic electron mirror as a function of the ratio of accelerating voltage to mirror voltage. The spherical and chromatic aberration coefficients of the mirror are of opposite sign (overcorrected) from those of electron lenses (undercorrected). This important property invites one to find a way to incorporate a correcting mirror in an electron microscope. Unfortunately, the parts of the beam heading toward and away from the mirror must be separated. A transverse magnetic field can separate the beams, but in general the deflection aberrations degrade the image. The key to avoiding the detrimental effects of deflection aberrations is to have deflections take place at image planes. Our separating system is shown in Fig. 1. Deflections take place at the separating magnet and also at two additional magnetic deflectors. The uncorrected magnified image formed by the objective lens is focused in the first deflector, and relay lenses transfer the image to the separating magnet. The interface lens and the hyperbolic mirror acting in zoom fashion return the corrected image to the separating magnet, and the second set of relay lenses transfers the image to the final deflector, where the beam is deflected onto the projection axis.


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