Conception et réalisation d'un filtre pour le contrôle d'harmoniques d'un amplificateur de puissance

RÉSUMÉ: La suppression d'harmoniques dans les amplificateurs de puissance de classe F et de classe F inverse est nécessaire pour avoir un rendement maximal en puissance ajouté. Dans ce contexte, le travail consiste à étudier le filtre coupe-bande à base de lignes couplées interdigitées, comme l'élément adéquat pour le rejet d'harmoniques au niveau d'un amplifrcateur de puissance. Dans ce cadre, la synthèse de ce travail sera composée de deux parties. Dans la première partie du projet, nous étudions la structure proposée d'un filtre à base de cinq lignes couplées interdigitées, pour une fréquence fondamentale égale à 2,14 GHz. Cette étude permettra de montrer trois conceptions de filtre. La première conception représente le filtre coupe-bande à simple encoche qui permet la suppression du 3ème harmonique. La deuxième conception concerne le filtre coupe-bande à double encoche. Il est constitué de sept lignes couplées interdigitées dont les quatre lignes couplées aux bornes sont pliées. Cette conception permet le rejet des deux fréquences de résonances indépendamment, en variant les paramètres de chaque ligne pliée. Les résultats de mesure, après la fabrication de ce filtre, montrent que pour une fréquence fondamentale de 2,14 GHz, ler valeurs des pertes sont de 16,10 dB et de 20,30 dB, respectivement pour le 3ème harmonique (6,42 GHz) et le 5ème harmonique (10,70 GHz). La troisième conception concerne le filtre à triple encoche, qui est formé de neuf lignes couplées interdigitées adjacentes dont les six aux bornes sont pliées. Les résultats de fabrication de ce filtre montrent que les pertes sont de 15,70 dB, de 31,70 dB et de 30,10 dB respectivement pour les harmoniques à rejeter de 6,42 GHz, de 10,70 GHz et de 14,98 GHz. La deuxième partie du projet est divisée en deux étapes. Dans la première étape, nous avons conçu et fabriqué un amplificateur de puissance de classe F inverse en utilisant la technologie GaN HEMT qui fonctionne à 2,14 GHz en utilisant un filtre coupe-bande à simple encoche. Pour cet amplificateur, le 3ème harmonique est rejeté par le filtre et le 5ème harmonique est supprimé par une ligne de transmission traditionnelle λ/4 à 10,70 GHz. Ce filtre présente un minimum de perte d'insertion égale à 0,80 dB, au niveau de la fréquence fondamentale. Le rendement en puissance ajoutée mesuré est de 61,60 % avec un gain de 13 dB à 2,14 GHz. En utilisant la technologie de GaN HEMT, la seconde étape porte sur la fabrication et les tests de cet amplificateur de puissance. Ce dernier utilise un filtre coupe-bande à double encoche afin de supprimer le 3ème et le 5ème harmoniques d'un signal de fréquence fondamentale égale à 2,14 GHz. Il est enfin intéressant de noter que le rendement maximal mesuré en puissance ajoutée est égal à 66,30 % et le gain à 10,70 dB pour une fréquence de 2,14 GHz. -- Mot(s) clé(s) en français : Filtre coupe-bande, Suppression d'harmoniques, Amplificateur de puissance, GaN, Rendement en puissance ajoutée. -- ABSTRACT: The harmonic control is required to have maximum power added efficiency of Class-F and Inverse Class-F power amplifiers. In this context, we are investigating the band-stop filter based on inter-digital coupled lines for the harmonic suppression in a power amplifier. This work is divided into two parts: The first part is to investigate on the proposed filter structure based on five inter-digital coupled lines at a fundamental frequency of 2.14 GHz. In the first part, we proposed three concepts of filter: The first concept is a band-stop filter made up of five inter-digital coupled lines with two coupled lines at the end and bent to adjust the notch frequency. The second concept is a band-stop filter with dual notches. It is made up of seven inter-digital coupled lines with four coupled lines and they are bent at the end of the line. Those bent coupled lines make it possible to reject independently the harmonic frequency by varying the parameters of each bent line. At a fundamental frequency of 2.14 GHz, measured rejection for the third harmonic (6.42 GHz) and the fifth harmonic (10.70 GHz) are 16.10 dB and 20.30 dB. The third concept is a band-stop filter with triple notches. It is made up of nine adjacent inter-digital coupled lines. Six lines are bent at the end. The measurement results show that the S21 are 15.70 db, 31.70 dB and 30.10 dB for the harmonic frequencies of 6.42 GHz, 10.10 GHz and 14.98 GHz respectively. The second part is divided in two steps. In the first step, we designed and made inverse class F power amplifier using GaN HEMT technology at 2.l4 GHz with a single notch band-stop filter. For this amplifier, the third harmonic is rejected by a proposed band-stop filter and the fifth harmonic is suppressed by a traditional λ/4 transmission line at 10.70 GHz. This filter has an insertion loss of 0.80 dB at 2.14 GHz. The measured power added efficiency is 61.60 % with a gain of 13 dB at 2.14 GHz. In the second step, a power amplifier was designed and tested using a band-stop filter by suppressing the third and fifth harmonic at a fundamental frequency of 2.14 GHz. The measured maximum power added efficiency is 66.30 % with a gain of 10.70 dB at 2.l4 GHz. -- Mot(s) clé(s) en anglais : Band-stop filter, Harmonic suppression, GaN, Power added efficiency, Power amplifier

Comfort Women in Indonesia: A Consideration of the Prewar Socio-legal context in Indonesia and Japan

14 páginas, 5 figuras, 10 tablas.A mechanistic lactation model, based on a theory of mammary cell proliferation and cell death, was studied and compared to the equation of Wood (1967). Lactation curves of British Holstein Friesian cows (176 curves), Spanish Churra sheep (40 curves) and Spanish Murciano-Granadina goats (30 curves) were used for model evaluation. Both models were fitted in their original form using non-linear least squares estimation. The parameters were compared among species and among parity groups within species. In general, both models provided highly significant fits to lactation data and described the data accurately. The mechanistic model performed well against Wood's 1967 equation (hereafter referred to as Wood's equation), resulting in smaller residual mean square values in more than two-thirds of the datasets investigated, and producing parameter estimates that allowed appropriate comparisons and noticeable trends attributed to shape. Using Akaike or Bayesian information criteria, goodness-of-fit with the mechanistic model was superior to that with Wood's equation for 1 Lie cow lactation curves, with no significant differences between models when fitted to goat or sheep lactation curves. The rate parameters of the mechanistic model, representing specific proliferation rate of mammary secretory cells at parturition, decay associated with reduction in cell proliferation capacity with time and specific death rate of mammary secretory cells, were smaller for primiparous than for multiparous cows. Greater lactation persistency of cows compared to goats and sheep, and decrease in persistency with parity, were shown to be represented by different values of the specific secretory cell death rate parameter in the mechanistic model. The plausible biological interpretation and fitting properties of the mechanistic model enable it to be used in complex models of whole-cow digestion and metabolism and as a tool in selection programmes and by dairy producers for management decisions.Canada Research Chairs ProgramPeer reviewe

Methane emission: strategies to reduce global warming in relation to animal husbandry units with emphasis on ruminants

Concerns about global warming and greenhouse gases have increased the interest of governments and the public sector to find solutions. To reduce the effects of global warming caused by greenhouse gases, especially methane, it is necessary to change animal production systems and adopt new strategic approaches. The reduction of enteric methane in livestock is a long-standing problem regarding the energy efficiency of consumed feed. In this review, the sources of production, dissemination, and introduction of accepted scientific and practical solutions in order to reduce methane gas in breeding and production units of dairy cows have been investigated. To carry out this research, a thorough search was conducted in articles published in valid databases between 1967 and 2022. A total of 213 articles were reviewed, and after screening, 159 were included in the study and analyzed using a PRISMA flow diagram. In general, low livestock efficiency, low-quality feed, a shortage of knowledge, and inadequate investment are the main causes of emission of these gases in poor or developing countries. On the other hand, developing countries may not always have access to the same methods that are utilized in industrialized countries to minimize the production of methane and other greenhouse gases like nitrous oxide. According to their conditions, developing countries should use the available tools to reduce methane production and emission, considering the costs, local knowledge, feasibility, and local laws. In future, there will be a greater need for interdisciplinary research to look for sustainable and acceptable methods for reducing methane emissions and other greenhouse gases from animal husbandry units, especially dairy cows. To change the population of rumen methanogens, as the main producers of methane, strategies such as feeding management, addition of inhibitors and vaccination are suggested. Also, there is a need for more applied research for reducing methane emissions

Application of Wilmink’s Exponential Function in Genetic Analysis of 305-d Milk Production and Lactation Persistency in Holstein Cows of Razavi Khorasan

To estimate heritability and genetic trend for 305-d milk production and lactation persistency, a total of 130,668 monthly test day milk yields belonging to 15,183 first lactation Holstein cows in 131 herds and calved from 2000 to 2009 were used. To calculate 305-d milk yield as well as lactation persistency, estimated parameters of Wilmink’s exponential function were applied. The parameters of the function were estimated by SAS software. Genetic and environmental variance components and heritability of the traits were estimated by single trait animal model using DMU software. Genetic trend was estimated based upon weighted simple linear regression of average breeding values on calving year. Heritability estimate of 305-d milk yield and lactation persistency were found to be 0.184 and 0.05, respectively. A positive significant phenotypic trend (166.11 kg per year) was observed for 305-d milk yield while a non-significant genetic trend (-2.0107) was revealed for the trait. For the lactation persistency, there were no significant phenotypic (0.054 % per year) and genetic (0.003 % per year) trends over the period of time

A study on the Effects of some Environmental Factors on Milk Production Characteristics Estimated Based Upon Gompertz Nonlinear Function in Holstein Cows of Mashhad

In order to analyse the effects of some environmental factors on milk production characteristics of Holstein cows in dairy farms of Mashhad, a total of 46,420 test day milk records belonging to 5,323 first lactation cows calved between 1994 and 2007 were utilised. First, Gompertz non-linear function was fitted to test day milk records of individual cows using SAS software. Then, based upon the estimated parameters of the function, milk porduction characteristics including time to peak yield (TM), milk yield at peak time (YM), lactation milk yield (YL) and initial milk yield (Y0) were calculated. Analysis of the environmental factors for the traits was carried out through a set of linear mixed models. The fixed effects of herd, year, season of calving and sperm type were significant on all the traits. Holstein gene percentage had significant influence on YL, PT and Y0. Calving age had only significant affect on YM and Y0. The effect of days open was significant for YL, YM and TM. There were positive and significant annual phenotypic trends for YL (10.27 kg), YM (0.43 kg) and TM (2.84 d)

Effect of Two Different Levels of Fiber on Feed Intake, Average Daily Gain, Feed Efficiency and Ruminal Metabolites of Holstein Calves

This experiment was conducted to determine the effect of feeding alfalfa hay and starter fiber level on feed intake and performance of Holstein dairy calves, using thirty two male calves in a completely randomized design assigned to four diets in a 2×2 factorial arrangement. The experimental treatments were as follow: T1: starter with low fiber and without alfalfa hay, T2: starter with low fiber along with alfalfa hay, T3: starter with high fiber and without alfalfa hay and T4: starter with high fiber along with alfalfa hay. Results showed feed intake was not significantly different in pre-weaning and throughout the study but after weaning there was significant difference among treatments. Average daily gain of calves was not significantly different during pre-weaning period but during post-weaning and throughout the study there was significant difference among treatments for this trait. Feed efficiency was not significantly different among treatments in pre-weaning and post-weaning periods but it was significantly different during throughout the study. The results of this experiment showed adding fiber to dairy calves ration through both starter concentrate and alfalfa hay may reduce their performance

Growth Nutritive Value of Saffron Residues Harvested at Different Stages by in situ and in vitro (Gas Production) Methods

The chemical composition, ruminal degradability parameters, ruminal and post ruminal digestibility of saffron residues were determined using in situ and in vitro (gas production) methods. The harvested residues at late vegetative phase were compared with the residues harvested at the early dormant phase. The results showed that NDF and ADF concentration of harvested residues at early dormant phase were higher where as it content of CP was significantly (

Evaluation of anti-diabetic effects of hydroalcoholic extract of green tea and cinnamon on streptozotocin-induced diabetic rats

Today diabetes is one of the most common diseases in the world that affects half of the world population. The use of medicinal herbs especially green tea and cinnamon has been taken into consideration for relieving the symptoms of diabetes, but there were some different ideas about their effectiveness. So, this study was conducted to evaluate the effect of cinnamon and green tea extract, individually and in combination, on blood glucose and weight loss in diabetic mice with Streptozotocin (STZ). The experiment was performed on 50 Wistar rats.  A total of 50 rats were divided into 10 groups of 5 and STZ was injected at the dose of 40 mg/kg/day for 5 days intraperitoneally. After diabetes induction, three groups received, 50, 100 and 200 mg doses of green tea extract,  three groups received 50, 100 and 200 mg doses of cinnamon extract  and three final groups received 50, 100 and 200 mg doses of  cinnamon  and green tea in combination by gavages daily for 6 weeks. After each period of treatments, blood glucose and the weight of animals were determined. At the end of the sixth week, blood glucose and weight loss were improved in diabetic rats in a dose-dependent manner and the dose of 200 mg/kg extract cinnamon with green tea had the most appropriate synergic effect

The Impact of Dietary Berberine Supplementation during the Transition Period on Blood Parameters, Antioxidant Indicators and Fatty Acids Profile in Colostrum and Milk of Dairy Goats

The objective of this study was to investigate the effect of berberine (BBR) supplementation on productivity, antioxidant markers, and the fatty acid (FA) profile in the colostrum and milk of goats. Twenty-four primiparous Saanen goats were supplemented with 0, 1, 2, and 4 g/d (per goat) of BBR in control (CON), BBR1, BBR2, and BBR4 groups (n = 6 per group), respectively, from 21 days before expected kidding to 21 days after parturition. Blood sampling was carried out at −21, −14, −7, 0, 7, 14, and 21 d relative to delivery. Colostrum was collected within the first and second milking (d 1 of lactation), and milk was harvested weekly after kidding. Both BBR2 and BBR4 increased dry matter intake (DMI) (p ≤ 0.05) and energy balance (EB) as well as colostrum and milk production. Both BBR2 and BBR4 decreased (p ≤ 0.05) plasma levels of cholesterol, haptoglobin, and ceruloplasmin, while elevating the plasma albumin and paraoxonase (p ≤ 0.05), which may indicate that BBR mitigates inflammation during the transition period. BBR reduced (p ≤ 0.05) malondialdehyde (MDA) and increased (p ≤ 0.05) total antioxidant capacity (TAC), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) in blood, colostrum, and milk. Concentrations of de novo fatty acid in colostrum and milk were increased (p ≤ 0.05) with both BBR2 and BBR4. Free fatty acid (FFA) concentration in colostrum and milk fat were lower (p ≤ 0.05) in BBR2 and BBR4 compared to CON. The concentration of saturated fatty acids (SFAs) in colostrum and milk fat increased (p ≤ 0.05) with BBR2 and BBR4, while unsaturated fatty acids (USFAs) decreased (p ≤ 0.05) in milk. In summary, supplementation with at least 2 g/d BBR may enhance the EB and antioxidant status of dairy goats