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对Logistic增长的SIS模型实现反馈线性化和极点配置的一步设计 总被引:2,自引:0,他引:2
非线性系统极点配置状态反馈调节器的常用方法为两步设计,而且要求必须满足对合条件,对于一个高于二阶的实际系统很难满足这些严格的条件,精确线性化和极点配置一步设计的方法避免了严格的对合条件,本文将这种方法运用在非线性微分代数系统中,并将此法应用到生物系统上. 相似文献
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辽宁是东北林蛙Rana dybowskii主要分布地之一,种群数量巨大,其群体遗传多样性有待评估.本研究应用ISSR标记技术对东北林蛙4个种群105个样本进行研究,5个引物共获得44条清晰谱带,4个种群的多态位点率均大于75%,Nei's基因多样性为0.2851,Shannon信息指数为0.4476,显示了较高的遗传多样性.对遗传分化系数、Nei's遗传距离、AMOVA分子变异巢式方差分析和F-统计量等遗传参数的统计结果表明,辽宁东北林蛙种群间已经出现一定程度的遗传分化,分析认为,自然屏障(高山和平原等)以及栖息地片段化是其遗传分化形成的主要因素. 相似文献
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记述了中国产厕蝇属Fannia R.-D.1新种:暗棒厕蝇Fannia kelaenohaltera sp. nov,并与近缘种明厕蝇Fannia serena(Fann,1825)进行了比较鉴别其主要区别在于新种腋瓣淡黄色,平衡棒暗褐色,后足腹节前腹鬃列完整,均长大,触角第3节长为宽的1.5倍,腹部具灰黄色粉被,雄第5腹板宽大于长,在其基部较狭等。同时对川西厕蝇Fannia grahahi Chillcott,1961进行了雌性补充描述。新种模式标本保存于沈阳师范大学化学与生命科学学院昆虫标本室。正模♂,新疆托木尔峰海拔2 600m,1977-06-22,韩寅恒采。副模2♂♂,新疆托木尔峰海拔2 600m,1977-06-22,韩寅恒采。词源:暗棒厕蝇的名称来源于雄性平衡棒的颜色呈暗褐色的特征。 相似文献
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X. M. Li M. J. Chen J. Li L. J. Ma N. Bu Y. Y. Li L. H. Zhang 《Biologia Plantarum》2014,58(3):589-594
We have earlier reported that the endophyte infection can enhance photosynthetic capacity and antioxidant enzyme activities in rice exposed to salinity stress. Now, the changes in primary photochemistry of photosystem (PS) II induced by Na2CO3 stress in endophyte-infected (E+) and endophyte-uninfected (E-) rice seedlings were studied using chlorophyll a fluorescence (OJIP-test). Performance indices (PIABS and PITotal) of E- and E+ rice seedlings revealed the inhibitory effects of Na2CO3 on PS II connectivity (occurrence of an L-band), oxygen evolving complex (occurrence of a K-band), and on the J step of the induction curves, associated with an inhibition of electron transport from plastoquinone A (QA) to plastoquinone B (QB). In E+ seedlings, Na2CO3 effects on L and K bands were much smaller, or even negligible, and also there was no pronounced effect on the J step. Furthermore, the OJIP parameters indicated that 20 mM Na2CO3 had a greater influence on the photosystem (PS) II electron transport chain than did the 10 mM Na2CO3, and that changes were greater in E- than in E+. Endophyte infection was therefore deemed to enhance the photosynthetic mechanism of Oryza sativa exposed to salinity stress. 相似文献
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The present study examined the effect of salicylic acid (SA) pre-treatment on soybean seedlings exposed to cadmium and/or UV-B stress. Dry mass, pigment content, net photosynthetic rate (PN), stomatal conductance (gs), and transpiration rate (E) were decreased by the Cd and/or UV-B stress. SA alleviated the adverse effects of Cd and/or UV-B on growth, pigment content, PN, and gs, but did not mitigate the inhibitory effect of Cd/UV-B on E, or that of Cd on chlorophyll fluorescence parameters. Cd and/or UV-B induced oxidative stress and increased lipid peroxidation that was significantly decreased by SA pre-treatment. The Cd and/or UV-B increased superoxide dismutase (SOD) activity, decreased peroxidase (POD) activity, and catalase (CAT) activity was mostly unaltered. SA might act as one of the potential antioxidants as well as a stabilizer of membrane integrity to improve plant resistance to the Cd and/or UV-B stress. 相似文献
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中国蜉寄蝇属分类学研究(双翅目,寄蝇科)(英文) 总被引:1,自引:1,他引:0
蜉寄蝇属Phorocera隶属于双翅目Diptera寄蝇科Tachinidae追寄蝇业科Exoristinae追寄蝇族Exoristini,一般寄生于鳞翅口毒蛾科,夜蛾科和尺蛾科的幼虫;主要分布于古北区和新北区.该属区别于追寄蝇族Exoristini 其它属的特征为:眼后鬃列后方具黑毛,复眼具淡黄色长毛,单眼鬃位于前单眼后方,背中鬃3+3,翅内鬃0+3,腹部背板具心鬃.本文系统研究了中国蜉寄蝇属的4个已知种,勺肛蜉寄蝇P.assinilis,锥肛蜉寄蝇P.grandis,直条蜉寄蝇P.normalis和昏暗蜉寄蝇P.obscura;并首次描述了直条蜉寄蝇的雄性和采自我国辽宁本溪的1新种,辽宁蜉寄蝇Phorocera liaoningensis sp.nov.;编制了古北区本属6种雄性检索表.新种区别于近缘种勺肛蜉寄蝇的特征为:第4腹板后缘钝圆,中脉心角至中肘横脉的距离略长于心角至翅后缘的距离,雄性肛尾叶后面观端半部均匀变窄. 相似文献
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