| 1 | Dietary branched-chain amino acid assessment in broilers from 22 to 35 days of age显示文摘Background:Valine and isoleucine are similar in chemical structure and their limitation in broiler chicken diets.To evaluate their limitation and interactive effects,multivariate assessment nutrition studies for the branched-chain amino acids(BCAA)are needed.A three level(−1,0,+1),three-factor Box-Behnken design study was conducted to assess dietary BCAA ratios to lysine of 65,75,and 85 for valine,58,66,and 74 for isoleucine,and 110,130,and 150 for leucine in male and female Lohman Indian River broilers from 22 to 35 d of age.Results:Live performance of male broilers was not affected by BCAA level.However,male broilers fed increasing isoleucine had improved(P=0.07)carcass yield as leucine and valine were reduced.Female broilers had improved body weight gain(P=0.05)and feed conversion(P=0.003)when leucine and isoleucine were at their lowest levels,independent of valine,but increasing leucine impaired live performance and warranted concomitant increases in isoleucine to restore responses.Increasing dietary isoleucine and valine in female broilers increased breast meat yield(P=0.05),but increasing leucine tended to diminish the response.Conclusion:The female Lohman Indian River broiler is more sensitive to BCAA diet manipulation than males.Specifically,as dietary leucine is increased in female broilers,dietary isoleucine increases were needed to offset the negative effects.Both increases in dietary valine and isoleucine improved breast meat yield in female broilers,but only when birds were fed the lowest dietary leucine. | M.T.Kidd F.Poernama T.Wibowo C.W.Maynard S.Y.Liu | 2021 | Journal of Animal Science and Biotechnology2021，12，2： | 2 |
| 2 | Designing hetero-structured ultra-strong and ductile Zr-2.5Nb alloys:Utilizing the grain size-dependent martensite transformation during quenching显示文摘To further improve the service performance of Zr-2.5Nb alloy worked as pressure tubes in pressurized heavy water reactors,more investigation about the microstructure and thermomechanical processing route of Zr-2.5Nb alloy need to be conducted.In this work,a hetero-structured Zr-2.5Nb alloy was prepared by applying a novel technique.Microstructure analysis reveals that the alloy exhibits a grain sizedependent martensite substructure transition during post-rolling quenching.The hetero-structure consists of equiaxed primaryαgrains and the lamellae groups containing both parallelα’dislocation martensite andα’twin martensite.Compared with the previously reported Zr-Nb alloys,the present Zr-2.5Nb alloys manifest the highest yield strength(∼710 MPa),together with a high ultimate tensile strength(∼844 MPa)and good ductility(∼17.1%).The enhanced mechanical properties are found to arise from the properly controlled fraction/size of the two types of martensite,which not only significantly strengthens the alloy but also contributes to a stronger strain hardening.A model based on the grain-size-dependent critical resolved shear stress for dislocation slip and twinning has been proposed to explain theα’martensite substructures transition at a critical grain size dc=3.3μm.Below this size,the critical resolved shear stress(CRSS)for twinning is higher than that for theslip.Thus,theα’dislocation martensite is more favorable to form.Otherwise,theα’twin martensite would exhibit a high activity.The present work indicates that making use of the grain size-dependent martensite transformation to tailor the heterostructure in Zr alloys is an effective strategy to overcome the strength–ductility trade-off in the material. | S.Y.Liu J.Y.Zhang J.Kuang X.Y.Bao D.D.Zhang C.L.Zhang J.K.Yang G.Liu J.Sun | 2022 | Journal of Materials Science & Technology2022，，30： | 0 |
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