排序方式: 共有19条查询结果,搜索用时 12 毫秒
1.
平果铝高压溶出过程,结疤的形成是不可避免的,而且对生产带来的危害也很大。对结疤形成影响因素的研究,对于生产中结疤的治理,强化氧化铝生产具有十分重要的意义。 相似文献
2.
拜耳法高压溶出过程形成的结疤 ,对氧化铝生产是十分有害的 ,开展对其结疤性质的研究 ,对于探索结疤形成的机理及结疤的防治 ,提供了理论和实践依据 ,具有十分重要的意义。 相似文献
3.
小麦赤霉病是一种气候流行病,其发生流行程度的轻重,主要取决于当地4月下旬到5上旬小麦抽穗开花期20天内的气候条件,如果气温适合、湿度大时,则蔓廷成灾。本文是采用多因子综合相关法,通过计算条件频率得出预报方程,其历史拟合率高达95.6%。 相似文献
4.
不同杀菌剂对小麦赤霉病菌的毒力测定与田间药效试验 总被引:1,自引:0,他引:1
测定了6种杀菌剂对小麦赤霉病菌的毒力与田间病害防效,结果表明:氰烯菌酯和多菌灵对小麦赤霉病菌的毒力强,抑制中浓度EC50分别为0.23μg/m L和0.25μg/m L;戊唑醇的抑菌作用也较强,EC50为0.54μg/m L,甲基硫菌灵和三唑酮的抑菌作用明显较差.田间药效试验结果显示,25%氰烯菌酯500倍稀释液初花期喷雾对小麦赤霉病的防效达到83.84%,小麦千粒重比对照增加72.29%;50%多菌灵800倍稀释液处理防效达到79.43%,千粒重比对照增加74.87%.氰烯菌酯和多菌灵对小麦赤霉病的防效和保产效果均明显高于甲基硫菌灵、三唑酮、戊唑醇和嘧菌酯. 相似文献
5.
选取2004-2014年间发病期的气象因素为自变量,小麦赤霉病病穗率为因变量,借助神经网络的函数映射能力,采用Fletcher-Reeves算法的变梯度反向传播算法,建立了小麦赤霉病的气象预报模型.由于神经网络无法提供直观的函数来反映病穗率与气象因子之间的关系,为了进一步分析气象因子间的相关性,采用主成分分析法提取主成分,并利用回归分析得到线性函数关系,建立了偏最小二乘模型.神经网络预测模型平均预报精度达到99%,但只提供病穗率和气象因子之间的拓扑关系;偏最小二乘预测模型可以得到病穗率和气象因子之间直观的函数关系,模型平均预报精度达到97%.2种模型均具有较高的预报精度,对小麦赤霉病的预防工作具有一定的参考价值. 相似文献
6.
A chitinase gene (RCH8) in plasmid vector pCAMBIA1308 was delivered into 3 wheat cultivars (Yangmai 158, Wan 9210, Wanmai 32) by low energy Ar+ beam-mediated method. Preliminary calli from treated mature embryos were first selected on hygromycin (Hm, 20 or 30 mg/L) containing medium. After the resistant calli formed, they were transferred to the regeneration medium with 10 or 20 mg/L Hm. All the three wheat varieties obtained transgenic plants. PCR and PCR-Southern assays showed that most plants regenerated from the resistant calli were positive transgenic plants. Southern blot of the positive green plants confirmed stable integration of alien DNA into wheat genome. The plant transformation frequencies varied with the variety and ion dose implanted. Wanmai 32 possessed the highest transformation frequency, reaching 3.8% at a suitable implantation dose. The transformation frequency of Yangmai 158 and Wan 9210 varied from 0.5% to 2.5% and from 0.5% to 1.4%, respectively. Progeny test for resistance to wheat scab showed that the leaf extract of R1 generation inhibited the growth of wheat scab strain R0 and F15. 相似文献
7.
《科学通报(英文版)》2008,(22)
Leymus racemosus is highly resistant to wheat scab (Fusarum head bright). The transfer of scab resistant gene from L. racemosus to Triticum aestivum is of great significance for broadening the base of wheat resistance. In the present study, the pollen of T. aestivum-L. racemosus monosomic addition line with scab resistance was treated by irradiation with 1200 R 60Co-γ-rays prior to pollinating to emasculated wheat cv. Mianyang 85-45. Nine plants with a telocentric chromosome 7Lr#1S were observed in M1, and one ditelosomic substitution line 7Lr#1S was selected from selfcrossing progenies and confirmed by chromosome C-banding and GISH. Furthermore, a co-dominant EST-SSR marker CINAU 31 was employed to identify this substitution line. A pair of chromosome 7A of common wheat were found to be replaced by a pair of telocentric chromosome 7Lr#1S, and further investigation showed that chromosome configuration of the substitution line at MI of PMCs after GISH was 17.50○II W 2.19 IIW 0.42II7Lr#1S 1.08 I7Lr#1S 0.69 IW. Two telocentric chromosomes paired as a bivalent in 59.7% of PMCs. Abnormal chromosome behaviors of telocentric chromosomes were observed in part of PMCs at anaphase I and telophase I, including the moving of two telocentric chromosomes to the same pole, lagging and earlier separation of their sister chromatid. All these abnormal behaviors can be grouped into three distinct types of tetrads according to different numbers of 7Lr#1S in their daughter cells and various micronucleus in some tetrads. However, due to the high transmission frequency of the female and male gametes with a 7Lr#1S, 84% of the selfcrossing progeny plants had ditelosomic substitution. The substitution line showed high resistance to wheat scab in a successive two-year test both in the greenhouse and field; hence, the line will be particularly valuable for alien gene mapping, small fragment translocation induction and telosomic cytological behavior analysis. 相似文献
8.
通过对桑塔纳汽车后制动毂产生夹砂的机理和原因分析,本文提出提高型砂热湿拉强度能够有效防止因水份迁移所引起的夹砂现象.经过工艺试验,选择临安特制陶土大大提高型砂热温拉强度,在生产上有效防止了夹砂现象. 相似文献
9.
为评价甲基营养型芽孢杆菌SJ80与SJ81对马铃薯疮痂病的生防潜力,以疮痂链霉菌为指示菌,测试了其发酵上清液的理化稳定性,并与咯菌腈、辛菌胺醋酸盐2种农药进行对比,检测其粗提物的生物安全性和抑菌效果。采用牛津杯法抑菌试验,以抑菌直径测试SJ80与SJ81发酵液的最佳发酵时间,发酵上清液经不同温度、紫外照射、pH值及蛋白酶处理后,以抑菌率测试其稳定性,采用MTT法测定粗提物体外急性细胞毒性。结果表明:2种发酵上清液最佳发酵时间为3 d,经121 ℃处理30 min或紫外照射24 h后,抑菌率均高于90%;SJ81在pH=1~13的抑菌率保持在80%以上,有较好稳定性,SJ80在pH=1~11的抑菌趋势与SJ81的相似,在pH=13的抑菌率为0,耐碱性较弱;发酵上清液经碱性蛋白酶与胰蛋白酶处理2 h后,抑菌率均接近100%,对酶处理较稳定。体外急性毒性实验结果显示,SJ80、SJ81对 LO2细胞增殖的半数抑制量(IC50)分别为239,137 mg/L,对PC12细胞的IC50分别为266,161.3 mg/L;在农药的推荐使用量下,咯菌腈和辛菌胺醋酸盐的抑菌率分别为25.46%,0%,对应的细胞活力均低于50%,比发酵液毒性大且抑菌率低。可见,2种拮抗菌发酵上清液理化性质稳定,比农药安全性高,有突出的抑菌优势,具有生防潜力。 相似文献
10.
杨美玲 《暨南大学学报(自然科学与医学版)》1993,(1)
为了探讨碱性成纤维细胞生长调节因子(bFGF)对家兔实验性深Ⅱ度烫伤的治疗作用。治疗组采用bFGF 10μg/ml、3μg/ml、1μg/ml的3种浓度;对照组采用溶媒、磺胺嘧啶银盐、生理盐水。观察bFGF对家兔被80℃循环水所致深Ⅱ度烫伤的促愈合作用。结果表明,3种不同浓度的bFGF对家兔深Ⅱ度烫伤均具有促进烫区表面干燥,结痂和脱痂的作用。t检验的结果表明,在缩小痂皮面积方面各治疗组于涂药前后不同时点的对比,差并非常显著(P<0.01),但各对照组仅在第25天开始差异显著或非常显著(P<0.05或P<0.01);而痂皮脱落时间与各对照组相比10μg/ml组差异显著(P<0.05),3μg/ml、1μg/ml组脱痂时间除与生理盐水组相比未显示统计学意义外,其余均具有统计学显著性(P<0.05)。 相似文献