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内点罚函数法调用Powell法求优时的1个注 总被引:1,自引:0,他引:1
提出内点罚函数法调用 Powell法求优时存在的问题 ,通过分析 Powell法后 ,做出相应的改进 .结果表明 ,改进后的方法在计算精度和效率方面都明显优于原方法 . 相似文献
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Jamshid Ashigh Peter J. Smith François J. Tardif 《Pesticide biochemistry and physiology》2009,95(1):38-46
A population of Amaranthus powellii that had survived imazethapyr did not have any of the documented AHAS mutations causing resistance in this species in Ontario. The goal of this research was to confirm resistance in this population, determine its molecular basis and develop diagnostic tests. Whole plant dose-response experiments showed the resistant population had greater than 25-fold resistance to the selective agent imazethapyr at the whole plant level. Whole plant resistance to other herbicides ranged between 9-fold to flumetsulam and 85-fold to flucarbazone. This was confirmed at the enzyme level with resistance ranging between 25-fold to imazethapyr and 485-fold to thifensulfuron. AHAS from the resistant population had 16% higher specific activity than that of the susceptible population and it was also less sensitive to feedback inhibition by valine, leucine and isoleucine. Genomic DNA was extracted to PCR amplify and sequence the AHAS gene and to determine the applicability of diagnostic tests. Sequencing of the AHAS gene revealed a single point mutation of thymine1125 to guanine coding for an Asp376Glu substitution. Two different diagnostic tests, restriction fragment length polymorphism and PCR amplification of specific allele, were able to correctly identify the resistant population from the susceptible control and from other resistant populations. Although this mutation appears to confer higher resistance to pyrithiobac and flucarbazone, two herbicides not registered in Eastern Canada, it endows plants with enough protection to allow survival to imazethapyr, the main selective agent in Ontario. 相似文献
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黎毓鹏 《广西农业生物科学》1998,(Z1)
在实际的机构优化设计问题中,求解优化问题的切实可行的方法显得至关重要。本文以一个四连杆机构作为实例,立足编程的需要,对在约束优化问题上的内点惩罚函数方法和Pow-ell方法进行了多方面的探讨。 相似文献
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重庆三峡库区鲍威尔脐橙花期叶片矿质营养诊断 总被引:2,自引:0,他引:2
【目的】通过对重庆三峡库区江津和奉节鲍威尔脐橙果园叶片矿质元素测定并进行叶片营养状况诊断,为鲍威尔脐橙高产优质施肥方案的制定提供依据。【方法】以重庆三峡库区江津和奉节40个代表性12年生枳橙砧鲍威尔脐橙小区植株为试材,通过测定盛花期叶片中氮(N)、磷(P)、钾(K)、钙(Ca)、镁(Mg)、铁(Fe)、铜(Cu)、锰(Mn)、锌(Zn)元素的含量和小区产量,运用叶片营养组分分析法(CND)、诊断施肥综合法(DRIS)和标准含量适宜偏差百分数法(DOP)3种方法对两个地区低产组叶片营养状况进行诊断。【结果】根据CND拐点法确定高产园划分临界值为330 t·hm-2,其中仅有奉节地区6个小区满足此条件,占总样本15.0%,同时依据高产组叶片N、P、K、Ca、Mg、Fe、Mn、Cu和Zn等各营养元素含量范围确定上述元素适宜值分别为N(2.0±0.1)%、P(0.12±0.01)%、K(2.1±0.5)%、Ca(3.1±0.4)g·kg-1 DW、Mg (0.31±0.03)g·kg-1 DW、Fe(36.6±13.1)mg·kg-1 DW、Mn (51.4±21.6)mg·kg-1 DW、Cu(2.2±0.7)mg·kg-1 DW和Zn(12.3±1.5)mg·kg-1 DW;建立不同营养元素CND法叶标准参比值为VN*=3.62±0.07,VP*=0.78±0.08,VK*=1.36±0.21,VCa*=1.74±0.14,VMg*=-0.55±0.10,VFe*=-2.74±0.36,VMn*=-2.40±0.39,VCu*=-5.55±0.32,VZn*=-3.78±0.10;依据DRIS法对江津地区筛选出N/K、N/Fe、N/Cu、P/K、P/Fe、P/Cu、K/Fe、K/Cu、Ca/N、Ca/P、Ca/K、Ca/Fe、Ca/Mn、Ca/Cu、Mg/N、Mg/P、Mg/K、Mg/Fe、Mg/Cu、Mn/N、Mn/P、Mn/K、Mn/Mg、Mn/Fe、Mn/Cu、Mn/Zn、Zn/Ca、Zn/Mg、Zn/Fe、Zn/Cu等30个,奉节地区筛选出Ca/K、Mg/K、Mg/Zn、Mn/N、Mn/P、Mn/K、Mn/Ca、Mn/Mg、Mn/Fe、Mn/Cu、Cu/P、Cu/K、Cu/Mg、Cu/Fe等14个叶片营养浓度比值参数;根据叶片矿质元素含量适宜值采用CND、DRIS、DOP 3种方法对奉节低产小区和江津地区橘园盛花期叶片营养诊断。其中,CND法需肥顺序:江津为Ca>Mg>N>P>Mn,奉节为N>Ca>P>Zn>Fe>Mn;DRIS法需肥顺序:江津为Ca>Mg>>Mn>N>P,奉节为Zn>>Fe>Ca>Mn>N>Mg;DOP法需肥顺序,江津为Ca>Mn>Mg,奉节为Mn>>Zn>Fe>Ca>Mg>N。【结论】3种方法诊断结果表明,果园营养不平衡指数江津地区CND、DRIS、DOP分别为166.5、4 291.0、117.5,奉节低产小区分别为37.2、570.0、14.1,奉节果园营养平衡状况均优于江津,两产区均具有很大的增产潜力。 相似文献
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Casey A. Pennock Brian A. Hines Darek S. Elverud Travis A. Francis Mark C. McKinstry Benjamin J. Schleicher Keith B. Gido 《Fisheries Management and Ecology》2021,28(1):1-13
River-reservoir interfaces have been described as aquatic ecotones and contain strong environmental gradients of depth, turbidity and trophic resource abundance. These transitional habitats have traditionally been excluded by riverine and reservoir management schemes despite their prevalence in modern riverscapes. By systematically sampling shoreline habitats along a river-reservoir interface gradient from riverine to lacustrine zones with trammel nets in 2018–2019, strong patterns were identified in total species captured and individuals captured in the San Juan River-Lake Powell inflow, USA. Changes in assemblage structure were driven mainly by increases in relative abundance of benthic omnivores towards the riverine zone, including imperiled razorback sucker, Xyrauchen texanus (Abbott), but also by increases in predatory species, such as striped bass, Morone saxatilis (Walbaum). Inter-annual variation in species distributions along the river-reservoir interface gradient was likely influenced by variation in reservoir water level that differed by nearly 12 m between years. River-reservoir interfaces provide high-quality feeding and potentially spawning areas for both benthic omnivores and piscivores, and these areas should be considered in management and conservation efforts for species using these habitats. 相似文献
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