内孤立波(internal solitary wave,ISW)的传播扰动声速场,进而引起声场周期起伏。本文利用数值仿真的研究手段,研究了内孤立波在不同类型的初始发射角度声线的多个声线上转折区域中传播时对声场产生的周期性影响,分析了对于声线掠射角...内孤立波(internal solitary wave,ISW)的传播扰动声速场,进而引起声场周期起伏。本文利用数值仿真的研究手段,研究了内孤立波在不同类型的初始发射角度声线的多个声线上转折区域中传播时对声场产生的周期性影响,分析了对于声线掠射角度、声能量到达时间这两个物理量的起伏频率,发现利用声学参数-时间曲线两点间的斜率与差值的偶次平方的乘积(product of the slope and the even square of the difference between two points of the acoustic parameter-time curve,PSD)处理方法更容易从这两种物理量中提取到显著的声场起伏特征。此外,讨论了高阶PSD参数对声场起伏特征提取效果的影响。结果表明,合适的高阶PSD参数可以提高PSD处理方法对声场起伏特征的提取能力。展开更多
Due to the enigmatical electrostatic potential difference between the inside and outside layers,the relationship between the diameter and the photocatalytic property of the Janus transition metal dichalcogenides nanot...Due to the enigmatical electrostatic potential difference between the inside and outside layers,the relationship between the diameter and the photocatalytic property of the Janus transition metal dichalcogenides nanotube is still unclear.In this job,for the first time we calculate the electrostatic potential difference of the Janus WSSe armchair nanotubes with corresponding building block models through the first principles calculations.The electrostatic potential difference increases as the diameter increases.Then,it is observed that the WSSe armchair nanotubes with smaller diameter have stronger oxidation capacity,weaker reduction capacity,and higher solar-to-hydrogen conversion efficiency.Furthermore,the diminution of diameter could make the band gap drop,and even cause a direct-indirect transformation of band structure.The adjustment of diameter could also regulate the ability of adsorbing water molecules at the insider and outside layers.Moreover,the suitable band edge positions,wide optical absorbance region(to the near-infrared),outstanding solar-to-hydrogen efficiency(up to 28.99%),high carrier separation,adequate photoexcited carrier driving forces,as well as the energetic and thermal stability,render these nanotubes befitting the photocata lytic water-splitting application.Our study not only predicts a kind of ideal water-splitting photocatalyst,but also shows an effective way to improve their photocatalytic performances.展开更多
For the experiment, 8 newborn male Holstein calves were selected that had the same feeding environment, and were of similar ages. They were randomly <span style="font-family:Verdana;">divided into 2 gr...For the experiment, 8 newborn male Holstein calves were selected that had the same feeding environment, and were of similar ages. They were randomly <span style="font-family:Verdana;">divided into 2 groups, with 4 in each group. The treatments consisted of </span><span style="font-family:Verdana;">feeding active probiotics (Group P) and a normal fed control group (Group C). The growth performance and blood indices were measured;rumen fluid samples were collected after weaning, and 16SrDNA sequencing and LC-MS metabolome detection were performed. Compared with the control group, </span><span style="font-family:Verdana;">relative abundances of Deltaproteobacteria, Desulfovibrionales, Bacteroi</span><span style="font-family:Verdana;">dales_ </span><span style="font-family:Verdana;">BS11_gut_group, Desulfovibrionaceae, Bacteroidales_S24-7_group, Acet</span><span style="font-family:Verdana;">obacteraceae, Ruminococcaceae_NK4A214_group, Asaia, [</span><i><span style="font-family:Verdana;">Ruminococcus</span></i><span style="font-family:Verdana;">] </span><i><span style="font-family:Verdana;">gauvreauii</span></i><span style="font-family:Verdana;">_group, </span><i><span style="font-family:Verdana;">Desulfovibrio</span></i><span style="font-family:Verdana;">, </span><i><span style="font-family:Verdana;">Kingella</span></i><span style="font-family:Verdana;">, </span><i><span style="font-family:Verdana;">Selenomonas</span></i><span style="font-family:Verdana;">, Lachnoclostri</span><span style="font-family:Verdana;">dium in group P were significantly different (P < 0.05). In group P, the metabolite </span><span style="font-family:Verdana;">of </span><span style="font-family:Verdana;">2-methylbenzoic acid and myo-inositol were significantly increased (P <</span><span style="font-family:Verdana;"> 0.05). These results showed that compared with normally fed calves, the growth performance and blood indices of probiotic-fed calves were changed, but the differences were not significant. Probiotic-fed calves showed significant differences in rumen fluid and a small number of metabolites, which were mainly involved in the pathway of carbohydrate metabolism. It proves </span><span style="font-family:Verdana;">that the supplemental active probiotics had an effect on the rumen microflora.</span>展开更多
The aim of this study was to investigate the effects of </span><i><span style="font-family:Verdana;">Saccharomyces cerevisiae</span></i><span style="font-family:Verdana;...The aim of this study was to investigate the effects of </span><i><span style="font-family:Verdana;">Saccharomyces cerevisiae</span></i><span style="font-family:Verdana;"> and its fermentation products on performance, blood hormone levels and rumen floral composition in peripartum dairy cows. Sixty perinatal cows were selected and allocated to two groups according to parity and expected date of delivery. Each group was supplemented with </span><i><span style="font-family:Verdana;">Saccharomyces cerevisiae</span></i><span style="font-family:Verdana;"> and its fermentation product 0 or 100 g. The results showed that </span><i><span style="font-family:Verdana;">Saccharomyces cerevisiae</span></i><span style="font-family:Verdana;"> and its fermentation products could significantly increase the feed intake of peripartum dairy cows (P < 0.01), increase the lactose content after 21 days postpartum (P < 0.01), and tend to increase milk production (P = 0.052). There was no significant effect on other milk components, the apparent digestibility of nutrients. There was a tendency to increase milk production and reduce the number of somatic cells in milk;increase blood levels of glucagon (P < 0.01) and </span><i><span style="font-family:Verdana;">β</span></i><span style="font-family:Verdana;">-hydroxybutyrate (P = 0.01), reducing the insulin content (P = 0.02).</span></span><span style="font-family:""> </span><i><span style="font-family:Verdana;">Saccharomyces cerevisiae</span></i><span style="font-family:""><span style="font-family:Verdana;"> reduced the abundance of rumen microbes in peripartum dairy cows but had no effect on rumen microbial diversity. Compared with the control group, the supplemented group showed reductions in the abundance of genera </span><i><span style="font-family:Verdana;">Bacillus</span></i><span style="font-family:Verdana;"> (P = 0.03), </span><i><span style="font-family:Verdana;">Butyrivibrio</span></i><span style="font-family:Verdana;"> (P = 0.01), </span><i><span style="font-family:Verdana;">Denitrobacterium</span></i><span style="font-family:Verdana;"> (P = 0.01), and </span><i><span style="font-family:Verdana;">Mogibacterium</span></i><span style="font-family:Verdana;"> (P < 0.01), </span><i><span style="font-family:Verdana;">Porphyromonas</span></i><span style="font-family:Verdana;"> (P = 0.05), </span><i><span style="font-family:Verdana;">Saccharofermentans</span></i><span style="font-family:Verdana;"> (P < 0.01), </span><i><span style="font-family:Verdana;">Sphaerochaeta</span></i><span style="font-family:Verdana;"> (P = 0.02), </span><i><span style="font-family:Verdana;">Streptococcus</span></i><span style="font-family:Verdana;"> (P = 0.04) and other genera. There were significant increase in the content of </span><i><span style="font-family:Verdana;">Acidaminococcus</span></i><span style="font-family:Verdana;"> (P = 0.03), </span><i><span style="font-family:Verdana;">Allisonella</span></i><span style="font-family:Verdana;"> (P < 0.01), </span><i><span style="font-family:Verdana;">Bulleidia</span></i><span style="font-family:Verdana;"> (P < 0.01), </span><i><span style="font-family:Verdana;">Corynebacterium</span></i><span style="font-family:Verdana;"> (P = 0.01), </span><i><span style="font-family:Verdana;">Dialister</span></i><span style="font-family:Verdana;"> (P < 0.01), </span><i><span style="font-family:Verdana;">Faecalibacterium</span></i><span style="font-family:Verdana;"> (P = 0.02), </span><i><span style="font-family:Verdana;">Faekalitalea</span></i><span style="font-family:Verdana;"> (P = 0.03), </span><i><span style="font-family:Verdana;">Fibrobacter</span></i><span style="font-family:Verdana;"> (P = 0.04), </span><i><span style="font-family:Verdana;">Flavobacterium</span></i><span style="font-family:Verdana;"> (P = 0.03), </span><i><span style="font-family:Verdana;">Kandleria</span></i><span style="font-family:Verdana;"> (P < 0.01), </span><i><span style="font-family:Verdana;">Paraprevotella</span></i><span style="font-family:Verdana;"> (P < 0.01), </span><i><span style="font-family:Verdana;">Pyramidobacter</span></i><span style="font-family:Verdana;"> (P = 0.05), </span><i><span style="font-family:Verdana;">Roseburia</span></i><span style="font-family:Verdana;"> (P < 0.01), </span><i><span style="font-family:Verdana;">Succinivibrio</span></i><span style="font-family:Verdana;"> (P < 0.01) and other genera.</span></span><span style="font-family:""> </span><span style="font-family:""><span style="font-family:Verdana;">The main metabolic pathways such as tryptophan metabolism and steroid hormone biosynthesis in perinatal dairy cows were determined for </span><i><span style="font-family:Verdana;">Saccharomyces cerevisiae</span></i><span style="font-family:Verdana;"> and its fermentation products.展开更多
In order to realize the application of corn stalk in cow feed, we designed experiments to explore the effect of a certain proportion of corn stalk on the performance of lactating dairy cows. 9 multiparous mid-lactatin...In order to realize the application of corn stalk in cow feed, we designed experiments to explore the effect of a certain proportion of corn stalk on the performance of lactating dairy cows. 9 multiparous mid-lactating cows were allocated at random to three groups, each containing 3 intact cows. The trial <span style="font-family:Verdana;">consisted of three periods and three dietary treatments with a 3 × 3 Latin</span> <span style="font-family:Verdana;">square design. The diets were normal concentrats plus dried corn stalk</span><span style="font-family:Verdana;"> chopped to 5 - 8 cm long (N), high concentrates plus dried corn stalks chopped to a length of approximately 5 - 8 cm by a mower (H) while the milled corn stalks were passed through a pulviser with a 2 cm pore size (MH). Each cow was measured for dry matter intake (DMI), ruminal pH, rumen fermentation, se</span><span style="font-family:Verdana;">lective feeding behavior and production performance. The results showed</span><span style="font-family:Verdana;"> that MH led to a significantly higher intake of DM, neutral detergent fiber (NDF), forage NDF (FNDF), acid detergent fiber (ADF), crude protein (CP) and organic matter (OM) than N and H (</span><i><span style="font-family:Verdana;">P</span></i><span style="font-family:Verdana;"> < 0.05). Cows fed H and MH showed similar selective feeding behavior, while those fed H showed various selectiv</span><span style="font-family:Verdana;">ity for the dietary component. MH resulted in a significantly higher milk</span><span style="font-family:Verdana;"> production (</span><i><span style="font-family:Verdana;">P</span></i><span style="font-family:Verdana;"> < 0.05), and tended to have a higher milk fat production than N (</span><i><span style="font-family:Verdana;">P</span></i><span style="font-family:Verdana;"> = 0.055). There were no significant differences in the milk components (</span><i><span style="font-family:Verdana;">P</span></i><span style="font-family:Verdana;"> = 0.424) and lactose (</span><i><span style="font-family:Verdana;">P</span></i><span style="font-family:Verdana;"> = 0.113) between cows fed N and MH. The high-con</span><span style="font-family:Verdana;">centrates plus milled corn stalk diet can increase the milk yield under the</span><span style="font-family:Verdana;"> premise of normal rumen pH in dairy cows, thereby generating higher economic benefits. And milled corn stalk can effectively inhibit the cow’s selective eating of low-quality roughage.</span>展开更多
文摘内孤立波(internal solitary wave,ISW)的传播扰动声速场,进而引起声场周期起伏。本文利用数值仿真的研究手段,研究了内孤立波在不同类型的初始发射角度声线的多个声线上转折区域中传播时对声场产生的周期性影响,分析了对于声线掠射角度、声能量到达时间这两个物理量的起伏频率,发现利用声学参数-时间曲线两点间的斜率与差值的偶次平方的乘积(product of the slope and the even square of the difference between two points of the acoustic parameter-time curve,PSD)处理方法更容易从这两种物理量中提取到显著的声场起伏特征。此外,讨论了高阶PSD参数对声场起伏特征提取效果的影响。结果表明,合适的高阶PSD参数可以提高PSD处理方法对声场起伏特征的提取能力。
基金supported by the National Natural Science foundation of China(Nos.11804006 and U20041103)the Henan Key Program of Technology Research and Development(No.182102310907)+1 种基金the Henan College Key Research Project(No.19A430006)the China Scholarship Council(No.201908410036)。
文摘Due to the enigmatical electrostatic potential difference between the inside and outside layers,the relationship between the diameter and the photocatalytic property of the Janus transition metal dichalcogenides nanotube is still unclear.In this job,for the first time we calculate the electrostatic potential difference of the Janus WSSe armchair nanotubes with corresponding building block models through the first principles calculations.The electrostatic potential difference increases as the diameter increases.Then,it is observed that the WSSe armchair nanotubes with smaller diameter have stronger oxidation capacity,weaker reduction capacity,and higher solar-to-hydrogen conversion efficiency.Furthermore,the diminution of diameter could make the band gap drop,and even cause a direct-indirect transformation of band structure.The adjustment of diameter could also regulate the ability of adsorbing water molecules at the insider and outside layers.Moreover,the suitable band edge positions,wide optical absorbance region(to the near-infrared),outstanding solar-to-hydrogen efficiency(up to 28.99%),high carrier separation,adequate photoexcited carrier driving forces,as well as the energetic and thermal stability,render these nanotubes befitting the photocata lytic water-splitting application.Our study not only predicts a kind of ideal water-splitting photocatalyst,but also shows an effective way to improve their photocatalytic performances.
文摘For the experiment, 8 newborn male Holstein calves were selected that had the same feeding environment, and were of similar ages. They were randomly <span style="font-family:Verdana;">divided into 2 groups, with 4 in each group. The treatments consisted of </span><span style="font-family:Verdana;">feeding active probiotics (Group P) and a normal fed control group (Group C). The growth performance and blood indices were measured;rumen fluid samples were collected after weaning, and 16SrDNA sequencing and LC-MS metabolome detection were performed. Compared with the control group, </span><span style="font-family:Verdana;">relative abundances of Deltaproteobacteria, Desulfovibrionales, Bacteroi</span><span style="font-family:Verdana;">dales_ </span><span style="font-family:Verdana;">BS11_gut_group, Desulfovibrionaceae, Bacteroidales_S24-7_group, Acet</span><span style="font-family:Verdana;">obacteraceae, Ruminococcaceae_NK4A214_group, Asaia, [</span><i><span style="font-family:Verdana;">Ruminococcus</span></i><span style="font-family:Verdana;">] </span><i><span style="font-family:Verdana;">gauvreauii</span></i><span style="font-family:Verdana;">_group, </span><i><span style="font-family:Verdana;">Desulfovibrio</span></i><span style="font-family:Verdana;">, </span><i><span style="font-family:Verdana;">Kingella</span></i><span style="font-family:Verdana;">, </span><i><span style="font-family:Verdana;">Selenomonas</span></i><span style="font-family:Verdana;">, Lachnoclostri</span><span style="font-family:Verdana;">dium in group P were significantly different (P < 0.05). In group P, the metabolite </span><span style="font-family:Verdana;">of </span><span style="font-family:Verdana;">2-methylbenzoic acid and myo-inositol were significantly increased (P <</span><span style="font-family:Verdana;"> 0.05). These results showed that compared with normally fed calves, the growth performance and blood indices of probiotic-fed calves were changed, but the differences were not significant. Probiotic-fed calves showed significant differences in rumen fluid and a small number of metabolites, which were mainly involved in the pathway of carbohydrate metabolism. It proves </span><span style="font-family:Verdana;">that the supplemental active probiotics had an effect on the rumen microflora.</span>
文摘The aim of this study was to investigate the effects of </span><i><span style="font-family:Verdana;">Saccharomyces cerevisiae</span></i><span style="font-family:Verdana;"> and its fermentation products on performance, blood hormone levels and rumen floral composition in peripartum dairy cows. Sixty perinatal cows were selected and allocated to two groups according to parity and expected date of delivery. Each group was supplemented with </span><i><span style="font-family:Verdana;">Saccharomyces cerevisiae</span></i><span style="font-family:Verdana;"> and its fermentation product 0 or 100 g. The results showed that </span><i><span style="font-family:Verdana;">Saccharomyces cerevisiae</span></i><span style="font-family:Verdana;"> and its fermentation products could significantly increase the feed intake of peripartum dairy cows (P < 0.01), increase the lactose content after 21 days postpartum (P < 0.01), and tend to increase milk production (P = 0.052). There was no significant effect on other milk components, the apparent digestibility of nutrients. There was a tendency to increase milk production and reduce the number of somatic cells in milk;increase blood levels of glucagon (P < 0.01) and </span><i><span style="font-family:Verdana;">β</span></i><span style="font-family:Verdana;">-hydroxybutyrate (P = 0.01), reducing the insulin content (P = 0.02).</span></span><span style="font-family:""> </span><i><span style="font-family:Verdana;">Saccharomyces cerevisiae</span></i><span style="font-family:""><span style="font-family:Verdana;"> reduced the abundance of rumen microbes in peripartum dairy cows but had no effect on rumen microbial diversity. Compared with the control group, the supplemented group showed reductions in the abundance of genera </span><i><span style="font-family:Verdana;">Bacillus</span></i><span style="font-family:Verdana;"> (P = 0.03), </span><i><span style="font-family:Verdana;">Butyrivibrio</span></i><span style="font-family:Verdana;"> (P = 0.01), </span><i><span style="font-family:Verdana;">Denitrobacterium</span></i><span style="font-family:Verdana;"> (P = 0.01), and </span><i><span style="font-family:Verdana;">Mogibacterium</span></i><span style="font-family:Verdana;"> (P < 0.01), </span><i><span style="font-family:Verdana;">Porphyromonas</span></i><span style="font-family:Verdana;"> (P = 0.05), </span><i><span style="font-family:Verdana;">Saccharofermentans</span></i><span style="font-family:Verdana;"> (P < 0.01), </span><i><span style="font-family:Verdana;">Sphaerochaeta</span></i><span style="font-family:Verdana;"> (P = 0.02), </span><i><span style="font-family:Verdana;">Streptococcus</span></i><span style="font-family:Verdana;"> (P = 0.04) and other genera. There were significant increase in the content of </span><i><span style="font-family:Verdana;">Acidaminococcus</span></i><span style="font-family:Verdana;"> (P = 0.03), </span><i><span style="font-family:Verdana;">Allisonella</span></i><span style="font-family:Verdana;"> (P < 0.01), </span><i><span style="font-family:Verdana;">Bulleidia</span></i><span style="font-family:Verdana;"> (P < 0.01), </span><i><span style="font-family:Verdana;">Corynebacterium</span></i><span style="font-family:Verdana;"> (P = 0.01), </span><i><span style="font-family:Verdana;">Dialister</span></i><span style="font-family:Verdana;"> (P < 0.01), </span><i><span style="font-family:Verdana;">Faecalibacterium</span></i><span style="font-family:Verdana;"> (P = 0.02), </span><i><span style="font-family:Verdana;">Faekalitalea</span></i><span style="font-family:Verdana;"> (P = 0.03), </span><i><span style="font-family:Verdana;">Fibrobacter</span></i><span style="font-family:Verdana;"> (P = 0.04), </span><i><span style="font-family:Verdana;">Flavobacterium</span></i><span style="font-family:Verdana;"> (P = 0.03), </span><i><span style="font-family:Verdana;">Kandleria</span></i><span style="font-family:Verdana;"> (P < 0.01), </span><i><span style="font-family:Verdana;">Paraprevotella</span></i><span style="font-family:Verdana;"> (P < 0.01), </span><i><span style="font-family:Verdana;">Pyramidobacter</span></i><span style="font-family:Verdana;"> (P = 0.05), </span><i><span style="font-family:Verdana;">Roseburia</span></i><span style="font-family:Verdana;"> (P < 0.01), </span><i><span style="font-family:Verdana;">Succinivibrio</span></i><span style="font-family:Verdana;"> (P < 0.01) and other genera.</span></span><span style="font-family:""> </span><span style="font-family:""><span style="font-family:Verdana;">The main metabolic pathways such as tryptophan metabolism and steroid hormone biosynthesis in perinatal dairy cows were determined for </span><i><span style="font-family:Verdana;">Saccharomyces cerevisiae</span></i><span style="font-family:Verdana;"> and its fermentation products.
文摘In order to realize the application of corn stalk in cow feed, we designed experiments to explore the effect of a certain proportion of corn stalk on the performance of lactating dairy cows. 9 multiparous mid-lactating cows were allocated at random to three groups, each containing 3 intact cows. The trial <span style="font-family:Verdana;">consisted of three periods and three dietary treatments with a 3 × 3 Latin</span> <span style="font-family:Verdana;">square design. The diets were normal concentrats plus dried corn stalk</span><span style="font-family:Verdana;"> chopped to 5 - 8 cm long (N), high concentrates plus dried corn stalks chopped to a length of approximately 5 - 8 cm by a mower (H) while the milled corn stalks were passed through a pulviser with a 2 cm pore size (MH). Each cow was measured for dry matter intake (DMI), ruminal pH, rumen fermentation, se</span><span style="font-family:Verdana;">lective feeding behavior and production performance. The results showed</span><span style="font-family:Verdana;"> that MH led to a significantly higher intake of DM, neutral detergent fiber (NDF), forage NDF (FNDF), acid detergent fiber (ADF), crude protein (CP) and organic matter (OM) than N and H (</span><i><span style="font-family:Verdana;">P</span></i><span style="font-family:Verdana;"> < 0.05). Cows fed H and MH showed similar selective feeding behavior, while those fed H showed various selectiv</span><span style="font-family:Verdana;">ity for the dietary component. MH resulted in a significantly higher milk</span><span style="font-family:Verdana;"> production (</span><i><span style="font-family:Verdana;">P</span></i><span style="font-family:Verdana;"> < 0.05), and tended to have a higher milk fat production than N (</span><i><span style="font-family:Verdana;">P</span></i><span style="font-family:Verdana;"> = 0.055). There were no significant differences in the milk components (</span><i><span style="font-family:Verdana;">P</span></i><span style="font-family:Verdana;"> = 0.424) and lactose (</span><i><span style="font-family:Verdana;">P</span></i><span style="font-family:Verdana;"> = 0.113) between cows fed N and MH. The high-con</span><span style="font-family:Verdana;">centrates plus milled corn stalk diet can increase the milk yield under the</span><span style="font-family:Verdana;"> premise of normal rumen pH in dairy cows, thereby generating higher economic benefits. And milled corn stalk can effectively inhibit the cow’s selective eating of low-quality roughage.</span>
