混流式水轮机固定部件动力特性分

提出了一种混流式水轮机固定部件动力分析附加质量的计算方法,通过引入质量单元将附加质量添加到固定部件结构的有限元控制方程,使用附加质量模型简化计算部件结构的流固耦合效应。与基于压力－位移格式的计算模型相比较,基于本文附加质量的模拟方法是可行的。     

Estimation of genetic variance components and heritabilities for cut-flower yield in gerbera using least squares and maximum likelihood methods

Summary Genetic variance components and heritability were estimated for cut-flower yield of gerbera in the Davis population using ordinary least squares and maximum likelihood methods. The overall estimate of narrow-sense heritability is 0.33 based on least squares (LS) and 0.31 based on maximum likelihood (ML). The results of the study indicate that (1) ML and LS provide very similar results if sample size is large enough, suggesting both are useful for plant breeding programs; (2) about one third of the variation in gerbera cut-flower yield is additive, implying selection in cut-flower will be successful; and (3) although additive variation gradually decreased, heritability remained near 0.27 suggesting there is still potential variation in the population for further selection.     

Characterization and inheritance of partial resistance to downy mildew, Peronospora parasitica, in breeding material of broccoli, Brassica oleracea convar. botrytis var. italica

Twenty doubled haploid broccoli lines from breeding material were evaluated for resistance to Peronospora parasitica at the seedling stage. All lines supported sporulation of the pathogen but to varying extents and intensities. Partial resistance of the more resistant lines,‘br8’and ‘br9′, reduced conidia production on cotyledons by 50-70% compared with the most susceptible lines. Inoculation of the two most resistant lines with 13 isolates of different geographical origins revealed that ‘br9′, showed a rather uniform level of resistance to all isolates while ‘br8’showed some isolate specificity Partial resistance was evaluated in six of the broccoli lines in a half diallel set of crosses. Disease assessment of seedlings showed that additive genetic effects explained 45.8% and 31.8% of the total variation of sporulation score and conidia production, respectively This suggests that recurrent selection for partial resistance to P. parasitica in early generation in breds or in populations of broccoli will be efficient to obtain cotyledon resistance.     

木粉/PVC复合材料挤出流动性的影响因素

研究木粉的粒径、添加剂的种类及配比等因素,对木塑复合材料挤出流动性的影响.结果表明:木粉粒径越小,复合物料在挤出过程中的流动性能越差,所制备的木塑复合材料色差越大,且产品材色越深.综合考虑加工特性和制品材色,宜选用木粉粒径45～60目;并添加稀土热稳定剂及铝酸酯偶联剂,可以提高物料的挤出流动性.     

江西吉安县松树针叶资源的开发利用前景

吉安县是江西省马尾松、湿地松的主要产区之一。大量松树针叶没有得到合理利用，本文叙述了松树针叶的综合利用方法及其在各方面的经济价值，对开发利用吉安县的松树针叶资源提出了几点的看法。     

具有两种免疫来源的乙肝病毒模型的全局动力学

研究了免疫反应具有两种来源的乙肝病毒模型.通过对相应特征方程的分析,讨论了感染平衡态和未感染平衡态的局部稳定性,证明了基本再生数1时疾病的持续性.通过几何方法的应用,得到了感染平衡点全局稳定性的充分条件.     

Detection and Analysis of High Temperature Sensitivity of TGMS Lines in Rice Using AMMI Model

With the AMMI(additive main effects and multiplicative interaction)analysis model,the determination of the sensitivity to temperature among different TGMS(thermo-sensitive genic male sterile)lines was performed. To assess the genetic differences due to high temperature stress at. the fertility-sensitive stage(10- 20 d before heading),seven genotypes(six TGMS lines and the control Pei-Ai64S)were grown from May 4 at seven different stages with 10d intervals. The temperatures at. the fertility-sensitive stages involved twelve levels from ＜ 20 to ＞30℃ under the regime natural conditions in Hangzhou,China. There was considerable variation in pollen fertility among genotypes in response to high temperature. Five genotypes identified as TGMS lines as their percentages of fertile pollens were lower than or close to that. of the. control except for the unstable line RTS19(V6). When the temperatures at. the fertility-sensitive stage were at Ⅰ -Ⅳ,Ⅴ-Ⅵ and Ⅶ-Ⅻ,the percentages of fertile pollens varied in the ranges of 46.46- 48.49%,19.62-22.79% and 3.49- 5.87%,respectively. The critical temperatures of sterility and fertility in the five TGMS lines were 25.1 and 23.0℃,respectively. Considering the amounts and directions of main effect and their IPCA(interaction principal components analysis),we can classify the lines and temperature levels into different groups,and describe the characteristics of genotyPe x temperature interaction,offering the information and tools for the development and utility of thermo-sensitive male sterile lines.Several TGMS rice lines with their reproductive sensitivity to high temperature that can be screened using the AMMI model may add valuable germplasm to the breeding program of hybrid rice.     

硝酸稀土添加剂对家兔心电图的影响

将24只家兔随机分为对照组和3个试验组,每组6只,每只每天分别补饲含0,10,20,30mg/kg的硝酸稀土添加剂配合饲料17.5g,补饲5d后,采用肢体导联测定心电图.从第16天开始,剂量改为0,20,40,60mg/kg,第20天时再测定.试验期30d.结果表明:1)波型上主要表现为:心电轴大多左移,大小不等的纤维波、Q异常波、QRS波、T波切迹或呈双峰;2)20mg/kg试验组与对照组心率无差异外,其他试验组与对照组差异显著(p<0.05);3)P-Q间期,随质量浓度的增加而时间缩短,T波时间延长;P波、QRS波群、Q-T间期时限变化不大.P波在10mg/kg下与对照组比较差异极显著(p<0.01),20mg/kg的质量浓度组差异显著(p<0.05),其他浓度组差异不显著.T波持续时限在10,40mg/kg下与对照组比较差异极显著(p<0.01),20,60mg/kg的质量浓度组与对照组比较差异显著(p<0.05).4)P波、QRS波、T波电压随稀土质量浓度的增高,表现为“前低中高后低”趋势,稀土质量浓度达60mg/kg时,各波电压呈下降趋势.     

促产蛋中草药剂的应用研究

根据中兽医学理论和动物营养学原理,中草药按一定比例混合后,粉碎过６０目筛,与氯化钾和多维混合均匀,制成以中草药为主体的促产蛋添加剂。在不同鸡场进行的４次试验表明,该添加剂可加快ＥＤＳ和ＩＢ患鸡以及热应激鸡恢复产蛋的速度,并对产蛋后期的鸡有一定的促产蛋作用。     

中药添加剂对断奶仔猪生产性能和腹泻率的影响

选取28日龄体质量相近的杜长大断奶仔猪72头,随机分成4个组,每组3个重复,每个重复6头,各重复公母猪各半进行28 d的饲养试验,试验共设对照组(基础日粮)、中药I组(基础日粮+1%中药配方I)、中药II组(基础日粮+1%中药配方II)、抗生素组(基础日粮+抗生素)4个处理,研究中药添加剂对断奶仔猪生产性能和腹泻率的影响。结果表明,饲粮中添加中药和抗生素提高了断奶仔猪的平均日增质量(ADG)(P>0.05),中药II组和中药I组显著改善了料肉比(P<0.05),抗生素组也有不同程度的改善(P>0.05);各试验组显著减小了仔猪腹泻的持续时间和腹泻频率(P<0.05),中药II组极显著降低了腹泻频率(P<0.01),显著降低了腹泻指数(P<0.05),而抗生素组和中药I组的腹泻指数与对照组相比无显著差异(P>0.05)。