A rectangular microstrip patch antenna using conventional Poly Tetra Fluride Ethelene (PTFE) substrate with air cavity is proposed and theoretically investigated. Considerably high gain along with improved front to ba...A rectangular microstrip patch antenna using conventional Poly Tetra Fluride Ethelene (PTFE) substrate with air cavity is proposed and theoretically investigated. Considerably high gain along with improved front to back radiation isolation is demonstrated using such proposed antenna. The radiation performance of this new antenna has been compared to a conventional microstrip patch for some commonly used aspect ratios (width to length ratio). Compared to conventional microstrip antenna the proposed configuration shows more than 12% increment in peak gain and more than 10% increment in front to back radiation performance in each set of aspect ratio. The elucidation of such improvement in the radiation characteristics of the proposed antenna is also presented.展开更多
In the present study, genetic parameters for longevity and genetic correlations with back fat （BF）, average daily gain （ADG）, and first mating age （FMA） were estimated from 19 300 Yorkshire and 18 378 Landrace s...In the present study, genetic parameters for longevity and genetic correlations with back fat （BF）, average daily gain （ADG）, and first mating age （FMA） were estimated from 19 300 Yorkshire and 18 378 Landrace sows from 12 farms derived from one breeding system. General linear models （GLM） were employed to estimate genetic correlations with heritability （h2）. Longevity was defined by six different parameters （i.e., traits） and heritability ranged from h2=0.13 to 0.16 （P〈0.05） in both swine breeds. Genetic correlations between different longevity definitions were positive and high （r=0.79 to 0.99; P〈0.05）. BF exhibited low positive genetic correlations （r=0.12 to 0.15; P〈0.05） with longevity traits identified in both pig breeds which were dependent on trait definition, whereas ADG and FMA showed weak negative genetic correlations with longevity traits. The influence of BF, ADG, and FMA on longevity traits was examined by dividing the production and reproductive traits into several numerical groups; the influence of each longevity trait was subsequently analyzed among the different groups. The results indicated BF was the best trait to improve longevity among BF, ADG, and FMA, which showed positive effects for almost all longevity traits. For Yorkshire sows, gilts with over 18 mm BF were most desirable; Landrace with 10.6-13 mm BF were suitable for longevity. ADG was not favorable for gilt selection, because the correlation between growth rate and longevity very low. For FMA, our results indicated gilts mating before 230 days exhibited a longer life span. Therefore, we suggest farmers should select for thicker back fat and mate at an earlier age to improve sow longevity.展开更多
文摘A rectangular microstrip patch antenna using conventional Poly Tetra Fluride Ethelene (PTFE) substrate with air cavity is proposed and theoretically investigated. Considerably high gain along with improved front to back radiation isolation is demonstrated using such proposed antenna. The radiation performance of this new antenna has been compared to a conventional microstrip patch for some commonly used aspect ratios (width to length ratio). Compared to conventional microstrip antenna the proposed configuration shows more than 12% increment in peak gain and more than 10% increment in front to back radiation performance in each set of aspect ratio. The elucidation of such improvement in the radiation characteristics of the proposed antenna is also presented.
基金supported by the grants from the National Swine Industry Technology System,China (CARS-36)the Guangdong Modern Agricultural Industry Technology System,Chinathe project from the Ministry of Science and Technology of China (2014 FY120800 and 2013 GA790001)
文摘In the present study, genetic parameters for longevity and genetic correlations with back fat （BF）, average daily gain （ADG）, and first mating age （FMA） were estimated from 19 300 Yorkshire and 18 378 Landrace sows from 12 farms derived from one breeding system. General linear models （GLM） were employed to estimate genetic correlations with heritability （h2）. Longevity was defined by six different parameters （i.e., traits） and heritability ranged from h2=0.13 to 0.16 （P〈0.05） in both swine breeds. Genetic correlations between different longevity definitions were positive and high （r=0.79 to 0.99; P〈0.05）. BF exhibited low positive genetic correlations （r=0.12 to 0.15; P〈0.05） with longevity traits identified in both pig breeds which were dependent on trait definition, whereas ADG and FMA showed weak negative genetic correlations with longevity traits. The influence of BF, ADG, and FMA on longevity traits was examined by dividing the production and reproductive traits into several numerical groups; the influence of each longevity trait was subsequently analyzed among the different groups. The results indicated BF was the best trait to improve longevity among BF, ADG, and FMA, which showed positive effects for almost all longevity traits. For Yorkshire sows, gilts with over 18 mm BF were most desirable; Landrace with 10.6-13 mm BF were suitable for longevity. ADG was not favorable for gilt selection, because the correlation between growth rate and longevity very low. For FMA, our results indicated gilts mating before 230 days exhibited a longer life span. Therefore, we suggest farmers should select for thicker back fat and mate at an earlier age to improve sow longevity.
