激素配比和pH值对蓝莓试管苗增殖生长的影响

该文以对土壤p H值适应性截然不同的蓝莓品种‘斯巴坦’和‘北陆’试管苗为试材,研究二者组织培养条件下对激素配比和p H值的要求。结果表明:‘斯巴坦’试管苗增殖培养基最佳激素配比为ZT0.3 mg/L+IBA 0.2 mg/L,p H值4.5;‘北陆’试管苗增殖培养基最佳激素配比ZT 0.3 mg/L+IBA 0.1 mg/L,p H值5.0。     

白花蛇舌草超微粉对小鼠免疫功能的影响

The assay was aimed to study the effect of Hedyotis diffusa Willd superfines powder on immune function. Three groups of mice were gavaged with the drugs at doses of 1.75,1.25 and 0.75 g/kg once a day for 7 consecutive days, repectively. The mice of control group were administered with the same volume of saline.At the last time, mice were injected into the muscle with Newcastle disease vaccine,and get peripheral blood on days 7, 14 and 21 after the medicine administration. The enhancement of innate immune responses were evaluated by using CCK-8 method, hemagglutination inhibition test, macrophage phagocytic function test and organ coefficient method. The levels of lymphocytes proliferative capacity, serum antibody, peritoneal macrophage phagocytosis and the indexes of immune organs in mice were extremely significantly enhanced (P＜0.01). Hedyotis diffusa dWilld superfines powder could extremely significantly regulate the immunity function of mice (P＜0.01).     

转角法施工镀锌高强螺栓关键技术

常州现代传媒中心主塔楼屋顶高88 m的钢塔(塔桅钢结构)设计工艺复杂,施工难度极大,所有钢构件均进行热浸锌防腐处理,采用8.8级热浸锌高强螺栓连接。考虑到钢结构拼接节点热浸锌高强螺栓的安装质量直接影响塔桅钢结构的安全和稳定,通过对热浸锌高强螺栓施工工艺进行反复论证、试验,最终确定采用转角法施工热浸锌高强螺栓,取得了理想的施工效果,确保了工程施工质量。     

法国凡尔赛宫苑的造园艺术成就

指出了法国的造园艺术成就最集中的体现就是凡尔赛宫苑.它在继承意大利园林的基础上,创造了一种新的“伟大风格”,反映了绝对的君权至上.凡尔赛宫宏伟壮丽、中轴线突出、严谨对称、风格多样等的特点,具有很高的艺术成就.     

射频识别技术在畜禽养殖中的应用与展望

随着畜禽规模养殖的发展,高度集约化养殖模式将影响畜禽的健康状况、疫病防控和福利水平。一种无接触、无应激的射频识别（Radio Frequency Identifi cation,RFID）技术应运而生,该技术可以在无损状态下采集畜禽的行为、生理生化和养殖环境指标,从而为评估集约化养殖的效果和影响提供基础数据。文章讨论了三种常见类型的RFID系统在畜禽养殖中的应用,系统地比较了各类系统的优缺点及适宜应用场景,进一步提出RFID在畜禽养殖中的未来应用方向,以期为深化畜禽信息采集的研究提供参考。     

木耳菌棒力学性能试验

以经过栽培的木耳菌棒为试验材料,在万能试验机上对不同含水率的菌棒试样进行剪切、压缩的力学性能试验。试验结果表明:含水率是影响菌棒剪切强度、抗压强度的重要自然因素。平均含水率分别为11.75%,21.16%,27.68%的菌棒其平均剪切强度分别为29.4k Pa、20k Pa、14.5k Pa。平均含水率分别为14.3%,24%的菌棒,其平均抗压强度分别为144.7k Pa、77.7k Pa。菌棒的含水率与剪切强度,抗压强度均呈幂指数关系。这些都为研制菌棒粉碎机械、选择粉碎参数提供了设计依据。     

基于模拟退火算法优化给水管线造价公式研究

给水管线造价公式的精确性对工程经济分析与给水管网优化的科学性和经济性有重大影响。通过五个地区的铸铁管综合单价数据,采用最小二乘法对各组数据进行多项式一至十次的拟合,确定了给水管线造价公式的最佳拟合次数为三次;进一步采用模拟退火算法对拟合的多项式参数进行优化计算,求解给水管线造价公式。结果表明:凭借模拟退火算法随机全局搜索模式以及不受函数性质影响的优势,能够克服传统算法难以求解多阶导数的困难,提高公式拟合精度。     

基于FEM-SPH耦合算法的土壤切削仿真研究

建立了旋耕刀和土壤的FEM-SPH耦合仿真模型,基于FEM-SPH耦合算法,采用MAT147土壤材料和国家标准Ⅲ型旋耕刀,结合LS-DYNA971求解器,对土壤切削仿真进行了研究。对旋耕刀切削土壤的耕作过程进行了数值仿真模拟分析,得到了切削力和切土能耗随时间的变化曲线;计算出旋耕刀单刀切土扭矩为8.75N·m,与试验结果接近。通过正交试验分析,耕作深度为主导因子,对切土功率影响较大,调整耕作深度可有效降低土壤切削的功耗,提高耕作效率。研究表明:FEM-SPH耦合算法可有效应用于土壤切削仿真,可为研究土壤的破碎机理和耕作器具的优化设计提供理论依据。     

Differences between primiparous and multiparous dairy cows in the inter-relationships between metabolic traits, milk yield and body condition score in the periparturient period

During the early postpartum period dairy cows mobilize fat and muscle to support lactation. This is associated with alterations in blood metabolite and hormone profiles which in turn influence milk yield and fertility. This study developed models to determine how metabolic traits, milk yield and body condition score were inter-related at different times in the periparturient period and to compare these relationships in primiparous (PP, n=188) and multiparous (MP, n=312) cows. Data from four previous studies which included information on blood metabolic parameters, parity, milk yield, body condition score and diet were collated into a single dataset. Coefficients of polynomial equations were calculated for each trait between -1 week pre-calving and week +7 postpartum using residual maximum likelihood modelling. The completed dataset was used in a multiple correlation model to determine how the best fit curves were related to each other over time. PP cows had higher concentrations of insulin-like growth factor-I and lower beta-hydroxybutyrate concentrations throughout, higher leptin concentrations pre-partum and both the peak in non-esterified fatty acids and the nadir in urea concentration occurred earlier after calving. These differences were associated with significantly lower milk production. Leptin concentrations fell at calving and were related to body condition score. Insulin was negatively correlated with yield in MP cows only. In MP cows the relationship between insulin-like growth factor-I and yield switched from negative to positive between weeks +4 and +7. Both beta-hydroxybutyrate and urea were positively related to yield in PP cows. In contrast, in MP cows beta-hydroxybutyrate was negatively correlated with yield and urea was strongly related to body condition score but not yield. These results suggest that there are differences in the control of tissue mobilization between PP and MP cows which may promote nutrient partitioning into growth as well as milk during the first lactation.