核桃细菌性疫病菌的特性及其与核桃内生菌的竞争

为了明确从湖北省丹江口市核桃病幼果上分离到的一株核桃细菌性疫病菌DW3F3的基本形态、生理生化特性、致病性相关特征以及与寄主内生菌的互作关系,对该病原菌进行了显微观察、生物膜形成测定,不同培养基上多糖和色素含量测定,18项生理生化指标测定,通过毛细管法和滴落法观察其趋化作用,并测试其与寄主内生菌的竞争能力。结果表明,病原菌DW3F3为杆状,极生鞭毛,有运动性,能形成生物膜。DW3F3在YPGAI、King's B和NA培养基上生长较好,而在NYG、PDA和LB培养基上产生多糖和色素较多。DW3F3有较强的耐盐性,致死温度达60℃,对纤维素和淀粉都有较强的分解能力,对HCl、NaCl和寄主叶片表现出一定的趋性。在与核桃叶部内生菌的共培养中,DW3F3表现出一定竞争优势。DW3F3有树生黄单胞菌核桃致病变种(Xanthomonas arboricola pv.juglandis,Xaj)的基本特征及致病相关特性,这些特征可能与其致病性强及病害难以控制有关。     

渔用浮标定位监视系统

介绍了几种常用的渔用浮标定位监视系统的基本组成、工作原理及各自的特点。着重对GPS渔用浮标定位监视系统的模式及各组成部分的功能和设计的关键技术进行了讨论。采取适当方法解决关键技术后,使GPS渔用浮标定位系统具有较强的抗干扰能力和信息自动交换能力,特别适合在海洋中容易漂移的渔具、航行器等设备中作位置监视、搜寻之用。     

可变直径滚轮式步行轮设计

步行轮具有出色的越障能力,受到科研工作者的重视和研究.为越过障碍物范围更广,行走机构设计成可变直径为佳,通过拟定设计要求,提出变直径方案,利用ANSYS对其进行结构分析,并试制出样机.通过实验证明,该步行轮可变直径广,结构简单,安全可靠.     

灌区整体利益下水价模型研究

水资源的合理配置利用,就是在对水资源系统的运行和演化机理进行科学分析的基础上,促进用户进行节水.目前,水资源管理的主要措施大都集中在加强行政管理和水资源配置机制方面.开源节流、加强管理只能是解决问题的外因,水资源的合理配置问题,最好由用水者自己来解决,由用水者的利益激励机制来解决,这样才能从根本上解决水资源的短缺和低效率应用问题.利益激励的关键在于水价的制定,拟从数学和管理2个角度,从供水方和用水方的利益激励出发,提出了同时考虑供水方、用水方统一的数学模型,并对模型进行了求解,为灌区水资源定价提供了依据.最后,对该模型的进一步完善指出了研究方向.     

基于布谷鸟搜索算法优化LSTM的大坝变形预测

对大坝变形进行合理分析和准确预测是确保大坝安全运行的重要手段.大坝变形监测数据具有趋势性、周期性、随机性和非线性等特性,现有的机器学习模型大都基于大坝变形监测数据的非线性特点进行构建,而忽略了监测数据还具有趋势性和周期性的线性特征.提出了一种大坝变形预测模型,通过采用布谷鸟搜索算法(CS)对长短期记忆人工神经网络(LSTM)进行优化,再基于物联网传感器的实时监测数据,使用局部加权回归的周期趋势分解方法(STL)将数据分解成趋势分量、周期分量和余项分量,采用优化后的LSTM模型对趋势分量和余项分量分别进行预测,并通过简单周期估计方法进行计算,将3个分量的预测结果求和后得到最终变形预测结果.试验选取浙江利山水库开展变形预测研究,结果表明：STL-CS-LSTM模型的水平和沉降变形预测精度都高于其他模型,水平位移预测精度由高到低依次为LSTM模型、支持向量回归模型SVR和人工神经网络模型ANN,沉降预测精度由高到低依次为ANN模型、LSTM模型、SVR模型.     

薯蓣茎段组织培养的研究

以薯蓣的单芽茎段为外植体,采用不同种类、浓度的植物生长调节剂进行离体培养。研究结果表明,以MS为基本培养基(蔗糖30g/L、琼脂6g/L),附加0.2 mg/L BA 0.01 mg/L NAA作为芽诱导培养基效果最好,诱导率高达83.2%,芽苗长势良好,叶片较大,叶色浓绿;继代增殖培养以MS 0.5 mg/L BA 0.05 mg/L NAA为最佳培养基,培养25d后增殖系数达4.38;诱导生根的最佳培养基为1/2 MS 0.2 mg/L IBA,生根率为86.7%,组培苗根系粗壮,长势旺盛。     

有效积温对中华常春藤生长的影响

通过调查中华常春藤的生境和测量茎的生长情况,总结了中华常春藤的种植特点和分枝方式,同时利用SPSS软件的回归分析建立回归模型,并根据建立的模型用Excel软件绘制坐标图。结果表明:中华常春藤主枝生长完毕所需的有效积温为2 718.34℃/d;茎伸长量随有效积温延续的变化呈"S"形曲线,而茎伸长速度变化趋于钟罩型单峰曲线。再利用此结果估算出:在理想的生长条件下采用三角形定植方式定植中华常春藤为宜,并且植株与植株之间的最佳定植密度为510 mm×510 mm。     

气调袋保鲜青菜头(茎瘤芥)的研究

检测青菜头贮藏过程中MA袋内气体指标变化和贮藏后的品质指标,并进一步探讨贮藏效果最佳MA袋的袋装量和硅窗面积对青菜头贮藏保鲜效果的影响。结果表明,PE硅窗袋、PVC硅窗袋和SCA袋内气体指标在一定时间后达到相对平衡,定期换气袋内气体呈不稳定周期性变化。PVC硅窗袋贮藏效果较好,PE硅窗袋和SCA袋次之,定期换气袋较差。当袋装量15 kg,硅窗面积为110 mm×75 mm时,PVC硅窗袋贮藏保鲜效果达到最好。     

Energy requirements of Dorper×thin-tailed Han crossbred ewes during non-pregnancy and lactation

This experiment was conducted to investigate the energy requirement of Dorper×thin-tailed Han crossbred ewes during non-pregnancy and lactation. Fifteen ewes after parturition were randomly assigned to three treatments: ad libitum(100%) feed intake and 80 or 60% ad libitum intake, and another nine non-pregnant ewes were assigned to a blank control group. Digestibility trials were performed in the non-pregnant ewes and in the lactating ewes on the 20 th, 50 th, and 80 th d of lactation. In parallel with the digestibility trial, a respirometry experiment was conducted to determine the methane and carbon dioxide production with an open-circuit respirometry system that was equipped with respiratory chambers. The net energy(NE) and metabolizable energy(ME) requirements for maintenance and growth were calculated using the carbon and nitrogen balance method. The results revealed that the carbon(C) and nitrogen(N) excretions and energy losses at faeces and urine, as well as the output of methane and CO2, increased significantly with decreasing feed intake(P0.01). The apparent digestibilities of C in th e stages of non-pregnancy and early, middle and late lactation were 55.8–58.3%, 62.5–73.8%, 64.8–71.3%, and 61.7–65.0%, respectively, and the apparent digestibilities of N were 45.2–51.3%, 73.7–82.7%, 72.8–80.5%, and 73.6–76.5%, respectively. The corresponding energy apparent digestibilities were 52.0–56.3%, 60.7–76.6%, 61.0–68.8%, and 61.4–67.7%, respectively. The ME/DE(digestible energy) values were 79.5–85.9%, 79.4–83.5%, 81.0%–85.3% and 78.6–82.9%, respectively. The maintenance requirements of NE, ME, and the efficiencies of ME utilisation for maintenance during the stages of non-pregnancy and early, middle and late lactation were 215.5, 253.1, 247.7, and 244.7 k J kg~(–1) BW0.75 d, and 372.4, 327.1, 320.9, and 362.0 k J kg~(–1) BW0.75 d, and 0.58, 0.77, 0.77, and 0.68, respectively. The ME requirement for the growth of non-pregnant ewes was 31.3 MJ kg~(–1) BW gain.     

输水渡槽最优断面优化设计

采用非线性模型,提出了输水渡槽的最优园底直角横断面。在同样水力条件下,最优园底直角断面的湿周是矩形最优断面的83.7%。