鸭疫里默氏杆菌贵州流行株蜂胶灭活疫苗制备

【目的】制备鸭疫里默氏杆菌(Riemerella anatipestifer,RA)贵州流行株蜂胶灭活疫苗。【方法】选取RA血清2型贵州流行株(RA-SS-8株)为基础菌株,依次利用分光光度法和平板计数法测定细菌生长曲线,再进行灭活条件筛选,以蜂胶为佐剂制备RA贵州流行株蜂胶灭活疫苗,并进行无菌检验、安全性检验及免疫鸭攻毒保护性试验。【结果】分光光度法测定RA-SS-8株菌液D_{600 nm}值随培养时间变化显示,细菌在0~3 h时增殖缓慢,在3~10 h时增殖趋势明显加快,在10 h以后增殖逐渐趋于平缓,随着培养时间的延长,细菌最终进入衰亡期;平板计数法结果显示,RA-SS-8株D_{600 nm}值为0.1~0.8时,该菌处于对数生长期,且D_{600 nm}值与活菌数呈现良好的线性关系;RA-SS-8株最佳灭活条件为0.2%甲醛溶液、37 ℃灭活12 h;蜂胶灭活疫苗含菌量为3.8×10⁹ CFU/mL,蜂胶干物质含量为10 mg/mL;无菌检验巧克力琼脂培养基上未见菌落生长;安全性检验以2倍免疫剂量接种雏鸭在观察期内未表现出不良反应,大体病变观察未见明显病变;免疫鸭攻毒保护性试验显示,蜂胶灭活疫苗免疫组鸭对RA-SS-8株的攻击后保护率为70%,蜂胶灭活疫苗对试验鸭心脏、肝脏组织均具有良好的保护效果。【结论】本研究成功制备了RA贵州流行株蜂胶灭活疫苗,为蜂胶灭活疫苗制备和动物免疫试验奠定基础。     

矿粉粒度及反应温度对高磷鲕状赤铁矿制备碳化铁的影响

基于对50根弯曲破坏钢筋混凝土圆柱低周反复试验结果的分析,建立了完整滞回环的数学表达式并推导得出等效阻尼比计算模型;以双柱墩桥梁为例,说明了建立桥梁整体结构等效阻尼比与墩柱端部塑性铰等效阻尼比关系的方法。研究表明,完整滞回环数学表达式较好地反映了弯曲破坏钢筋混凝土圆柱的滞回特性,得到的等效阻尼比模型计算结果与试验结果符合较好;采用建立的桥梁整体结构等效阻尼比与墩柱端部塑性铰等效阻尼比的关系进行pushover分析更能反映实际情况。采用等效阻尼比模型算得的目标位移与基于Rosenblueth模型和Kowalsky模型算得的位移之间存在较大差距。     

基于WebGIS构建森林资源信息发布系统

首先对森林资源信息发布系统的结构进行分析,并提出了利用ESRI公司的ArcIMS和MapObjectsJavaEdi tion进行二次开发,建立一个基于矢量数据的发布系统。系统采用了B/S结构,具有跨平台性及可扩充性。     

外源酶对大熊猫日粮营养物质消化率影响的研究

应用外源性复合酶制剂对移地保护大熊猫进行消化试验。结果表明 ,在日粮中添喂 0 15 %或 0 30 %的营养性复合酶或纤维素复合酶均能显著提高大熊猫对日粮各营养物质的消化率 ,其中 ,对日粮粗蛋白质和氨基酸的消化率 ,添喂 0 30 %的营养性复合酶的效果优于添喂 0 15 %水平的营养性复合酶的效果 ;对日粮粗脂肪的消化率 ,添喂 0 15 %水平的营养性复合酶的效果优于添喂 0 30 %水平的效果 ;大熊猫对日粮纤维素、半纤维素、NDF、ADF的消化率 ,添喂纤维素复合酶的效果极显著 ,而且 ,随添喂水平的提高 (0 15 %～ 0 30 % ) ,其日粮纤维素等物质的消化率亦随之显著提高 ;添喂营养性复合酶 ,纤维素等物质也获得了良好的助消化作用。     

Surface mulching and a sandy soil interlayer suppress upward enrichment of salt ions in salt-contaminated field

Purpose

The suppression effect of a sandy soil interlayer on topsoil enrichment of salt ions was investigated. However, whether this suppression effect was enhanced by surface mulching was little documented. The objectives of this study were to compare the suppression effects under different materials mulching, and to investigate an innovative method to suppress the soil salt ions down-to-top enrichment.

Materials and methods

In this study, the sandy soil layer was pre-positioned at 60–100 cm depth in a salt-contaminated site in advance, achieving the suppression effect on surface enrichment of salt components as expected. Three treatments were herein designed as bare field (CK), plastic film mulching (PM), and maize straw mulching (SM) to examine the dynamics of water and salt movement across soil profiles during the summer with strong evaporation.

Results and discussions

Results showed that total salt content was increased by 21.3 and 8.0% in CK and SM respectively, while decreased by 24.9% in PM at the end of strong evaporation period, comparing with the beginning. Thus, surface mulching further strengthened this suppression effect, but PM displayed better performance than SM did. The data also demonstrated that vertical transport of soil water was much restrained in PM and SM, accordingly inhibiting upward transfer of salt ions. Particularly, sodium adsorption ratio (SAR) ranged from 14.3–265.7, 17.9–147.1, 38.4–147.2 mmol^1/2 kg^?1/2 at a shallow soil layer (0–60 cm) in CK, PM, and SM, respectively.

Conclusions

The results suggested that sandy soil interlayer settings with plastic mulching are a critical technical strategy for salt-contaminated land reutilization and management.

     

河南部分地区花生田地下害虫发生情况调查

对河南省新乡和驻马店地区的花生田地下害虫进行调查的结果表明,花生田的地下害虫主要包括蛴螬、金针虫、蝼蛄等,以蛴螬为主要地下害虫,7月下旬的平均虫口密度为0.80～18.90头/m2,9月下旬的平均虫口密度为1.00～12.33头/m2。经过分类鉴定暗黑鳃金龟(Holotrichia parallela Motschulsky)和华北大黑鳃金龟［H. oblita (Faldermann)］为花生田蛴螬优势种。调查还发现,土壤类型、耕作方式、田间周围的植物布局及防治措施均对蛴螬的种群数量有明显影响。     

低比转数离心泵叶轮内流场重构与模态分析

针对传统离心泵水力性能优化设计的复杂性,提出采用本征正交分解-径向基函数（POD-RBF）混合代理模型方法对离心泵叶轮内流场进行重构分析。由三次Bezier曲线对低比转数离心泵二维叶片型线进行参数化控制,通过对叶片包角、进出口安放角等控制参数进行适量的扰动得到叶片型线的样本集。由叶片型线参数及叶轮CFD内流场数据构成样本的快照矢量集,根据几何相似及网格变形方法插值得到各相似节点的流场参数,依据本征正交分解法（POD）将快照集分解为一系列正交基的线性组合。由径向基函数（RBF）拟合目标叶型所对应的正交基系数,实现了对目标叶轮内流场的重构。采用POD-RBF方法对MH48-12.5型低比转数离心泵叶轮内流场进行了重构,其压力预测均方根误差为0.84%,速度预测误差基本在0.5m/s以内,流场预测所需时间约为CFD计算的1/240。对样本集进行POD基模态分析,得到了各阶基模态流场特征及能量分布特性。     

氮磷钾配施对灯盏花产量和品质的影响及肥料效应

为探究氮磷钾(NPK)肥配施对灯盏花产量和品质的影响及肥料效应,推荐灯盏花NKP肥最佳配比及施用量,本研究采用“3414”设计进行田间小区试验,测定灯盏花产量和主要提取成分野黄芩苷、总黄酮和总咖啡酸酯含量,并计算主要提取成分单位面积收获量,通过肥料效应函数方程拟合NPK施肥量。结果表明,合理施肥可显著提高灯盏花产量,同时氮磷钾肥对产量的影响有互作效应,互作效应大小依次为NPK>NP>NK>PK。氮磷肥互作表现为协同促进作用,而当施钾量处于低中水平时,氮钾肥间和磷钾肥间有协同促进作用。合理施肥可提高灯盏花主要提取成分单位面积收获量,减施或不施N肥,施用中等水平的磷肥和钾肥有利于提高灯盏花品质。综上,通过建立肥料效应函数,获得该地区最佳产量推荐施肥量为N 151.4 kg·hm^-2、P₂O₅ 120.7 kg· hm^-2、K₂O 71.0 kg · hm^-2,产量为13 807.2 kg · hm^-2;获得最高单位面积野黄芩苷收获量(310.7 kg · hm^-2)的施肥量为N 120.0 kg · hm^-2、P₂O₅ 92.1 kg · hm^-2、K₂O 113.6 kg · hm^-2。本研究结果为指导和规范灯盏花施肥技术提供了理论依据。     

浮潜式消防泵启动过程瞬态特性的数值模拟

为了研究浮潜式消防泵在启动过程中的瞬态特性,建立包含泵、水箱及循环管路在内的三维封闭模型,运用Fluent 145商用软件,采用RNG k-ε湍流模型,并结合UDF程序加载转速变化规律对模型进行非稳态数值模拟．分析泵在启动过程中其流量、扬程、叶轮加速转矩、总效率、叶轮轴向力及径向力随启动时间的变化规律．研究结果表明:泵在启动过程中其流量、扬程及总效率的变化主要取决于动力源的启动特性,并呈指数上升趋势,叶轮的加速转矩随启动时间的增加而逐渐减小;当泵转速达到额定转速时其加速转矩为0,在泵启动初期因流量严重偏离额定流量而导致其产生较大的轴向力及径向力,随着启动时间的增加,泵的轴向力及径向力逐渐减小,最后趋于稳定．研究为离心泵的优化设计、振动及噪声诊断提供理论参考．     

Physical simulation of fluid field and structure optimization in two-strand tundish

The influence of the structure and location of dam and weir on fluid flow state in a two-strand tundish is studied, and a set of optimal structure, combining with the average residence time calculated from RTD curve, is obtained. The result indicates that the fluid flow state can be changed and the path of the fluid flow can be prolonged as well as the average residence time is improved after using dam and weir. But there are some dead zones after fluid passed through the dam and weir. Combination scheme of No. one dam and weir is better than the others. Its average residence time is 299 s and the volume fraction of dead zone is 31.0%. After the optimization of flowing control parameters in tundish, the best case is that the distance between dam and weir is 290 mm and the distance between weir and the long nozzle is 383 mm. The longest average residence time is 351 s and the minimum volume fraction of dead zone is 19.0% under the above situation. Compared with that of no dam and weir, the average residence time increases by 65 s and the dead zone volume fraction decreases by 15.0%. Based on Newton formula, the calculated results show that the inclusions with diameter larger than 17.5 μm can float up within 351 s under this optimization situation.