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摄动类摆系统的总体性质及鲁棒稳定性 被引量:1
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作者 杨莹 黄琳 《控制理论与应用》 EI CAS CSCD 北大核心 2003年第1期8-12,共5页
研究了一类特殊的非线性控制系统———类摆系统在线性相关参数摄动下的总体性质及鲁棒稳定性 ,运用顶点检验和鲁棒严格正实性理论 ,得到了类摆系统在上述摄动模式下双态、Lagrange稳定及Bakaev稳定的条件 .结果表明对于这类系统 ,可以... 研究了一类特殊的非线性控制系统———类摆系统在线性相关参数摄动下的总体性质及鲁棒稳定性 ,运用顶点检验和鲁棒严格正实性理论 ,得到了类摆系统在上述摄动模式下双态、Lagrange稳定及Bakaev稳定的条件 .结果表明对于这类系统 ,可以通过有限检验分析其解的总体性质及鲁棒稳定性 . 展开更多
关键词 摄动类摆系统 性质 鲁棒稳定性 双态性 LAGRANGE稳定性 Bakaev稳定性 非线性控制系统
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Σ_e^n(n≥2)型Banach空间上的摄动类问题
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作者 曾清平 苏维钢 吴珍莺 《数学研究》 CSCD 2011年第4期366-374,共9页
深化对本性谱的认识;给出∑_e^n(n≥2)型Banach空间上的摄动类问题的反面回答.
关键词 ∑_e^n型Banach空间 半FREDHOLM算子 摄动类 本性谱
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复方配伍的摄动模糊聚类方法 被引量:5
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作者 高彦伟 郑文瑞 +1 位作者 韩燕 张爽 《生物数学学报》 CSCD 北大核心 2005年第2期219-222,共4页
利用摄动模糊聚类方法对中药复方桂枝汤的药群进行了分类,结果表明该方法优于传统模糊聚类方法,避免了利用传递闭包求模糊等价矩阵进行分类的失真问题,与中药传统组方原则相吻合.
关键词 方剂 模糊聚 模糊聚
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一类关联摄动大系统的分散鲁棒次优控制 被引量:1
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作者 胡寿松 唐建秋 《控制与决策》 EI CSCD 北大核心 1992年第5期335-341,共7页
本文从提高控制系统的可靠性出发,利用鲁棒性技术,对于一类关联摄动大系统导出了分散次优控制律,并使关联大系统对参数摄动具有稳定鲁棒性。文中释例的仿真结果表明,本文提出的方法是有效的。
关键词 鲁棒控制 大系统
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Lageos卫星精密定轨中“类阻力”摄动的计算
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作者 许华冠 朱元兰 《中国科学院上海天文台年刊》 1989年第10期96-102,共7页
在Lageos卫星的精密定轨中引入了“类阻力”摄动加速度,以减小沿轨误差的影响。本文讨论了“类阻力”摄动的阻力系数CD的不同计算模式对定轨计算的影响。通过实例计算和分析比较,表明了类阻力系数CD在各个短弧上拟合的值变化较大。在一... 在Lageos卫星的精密定轨中引入了“类阻力”摄动加速度,以减小沿轨误差的影响。本文讨论了“类阻力”摄动的阻力系数CD的不同计算模式对定轨计算的影响。通过实例计算和分析比较,表明了类阻力系数CD在各个短弧上拟合的值变化较大。在一个月的长弧段内把CD作为常系数拟合求解仅是一种求平均值的近拟方法。类阻力系数CD应采用既包含长期变化又包含若干周期变化的计算模式比较合理。具体计算时该取多少项,应根据选用弧段的长短及精度要求来确定。 展开更多
关键词 卫星 定轨精度 阻力”加速度 误差 阻力系数
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Caffeine Intake during Pregnancy: What Are the Real Evidences?
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作者 Thais de Merici Domingues e Paula Felipe Lioe Teh Shang +1 位作者 Helio Chiarini-Garcia Fernanda Radicchi Campos Lobato de Almeida 《Journal of Pharmacy and Pharmacology》 2017年第5期249-260,共12页
Caffeine is a substance presented in foods such as coffee, tea, soft drinks, chocolates and medicines and is commonly consumed by pregnant women. Due to its ability to cross the placental membrane and accumulate in th... Caffeine is a substance presented in foods such as coffee, tea, soft drinks, chocolates and medicines and is commonly consumed by pregnant women. Due to its ability to cross the placental membrane and accumulate in the fetus body, caffeine and its metabolites have been contraindicated or recommended in small doses during pregnancy. Studies in rodents relate caffeine intake to lower rates of fertilization, embryonic implantation, changes in placental structure, increased occurrence of low fetal and placental weights, abortion and stillbirth. However, in humans, studies involving caffeine consumption are inconclusive. Methodological complexity, difficulty for measuring caffeine intake and ethical reasons are limiting factors for a more accurate conclusion. So far, caffeine recommendation ranges from 100 to 300 mg/day. Even though researches have recommended low caffeine consumption by pregnant women in order to avoid deleterious consequences during gestation, a safe dose has not been established until now. The aim of the present review is to describe the main findings on the effects of caffeine consumption during pregnancy in both human and rodent experimental models. 展开更多
关键词 Caffeine intake PREGNANCY caffeine recommendation placenta.
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Ontogenetic changes in feeding and food preferences of the dog conch Laevistrombus canarium Linnaeus 1758 (Mollusca: Gastropoda) from Merambong shoal, Malaysia
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作者 HUSNA Wan Nurul Wan Hassan MAZLAN Abd Ghaffar COB Zaidi Che 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2017年第5期1230-1238,共9页
Laevistrombus canarium is one of the marine gastropod mollusks that have high commercial value, particularly in the aquaculture sector in Malaysia. This study was conducted to determine the feeding and food items of L... Laevistrombus canarium is one of the marine gastropod mollusks that have high commercial value, particularly in the aquaculture sector in Malaysia. This study was conducted to determine the feeding and food items of L. canarium at different ontogenetic stages (juveniles, sub-adults and adults) from Merambong shoals, Malaysia. Field observations on feeding activity were conducted, followed by detailed laboratory analysis on the stomach content. Five-minutes observations on randomly selected individuals were conducted at the field sampling site and their feeding activities were recorded with reference to age stage. Various shell sizes from each ontogenetic stage were randomly collected and quickly anaesthetized with ice and preserved in 10% formalin before being transported to the laboratory for stomach content analyses. Field observations showed that L. canarium mainly grazed on epiphytes occurring on seagrass (46.67%), followed by sediment surface (40%) and epiphytes occurring on macroalgae (13.33%). Stomach content analyses showed a significant difference (P〈0.05) in gastro-somatic index (Gasi) between the juveniles (0.39±0.05), sub-adults (0.68±0.09) and adults (0.70±0.05) (P〈0.05). Food items found in the conch stomach include diatoms, detritus, foraminifera, seagrass and macroalgae fragments, sand particles and shell fragments. The Index of Relative Importance (%IRI) indicates three main types of food dominated the three ontogenetic stages namely diatoms, sand particles and detritus. However, no significant difference (P〉0.05) was detected between the three main food items (diatoms, sand particles and detritus) among the ontogenetic stages. Therefore, feeding activity revealed the role of the dog conch in the marine food network. While, classification of the types of food consumed by L. canarium through stomach content analysis determines the particular position of the gastropod in the food chain. Further studies are needed to provide a better insight between trophic relationships ofL. eanarium with marine ecosystem. 展开更多
关键词 Laevistrombus canarium feeding activity gut contents Merambong shoal
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Mechanistic perspectives of calorie restriction on vascular homeostasis
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作者 LIU Yue CHEN HouZao LIU DePei 《Science China(Life Sciences)》 SCIE CAS 2014年第8期742-754,共13页
Calorie restriction(CR)is a dietary regime based on low calorie intake.CR without malnutrition extends lifespan in a wide range of organisms from yeast to rodents,and CR can prevent and delay the onset of age-related ... Calorie restriction(CR)is a dietary regime based on low calorie intake.CR without malnutrition extends lifespan in a wide range of organisms from yeast to rodents,and CR can prevent and delay the onset of age-related functional decline and diseases in human and non-human primates.CR is a safe and effective intervention to reduce vascular risk factors in humans.In recent years,studies in rodents have provided mechanistic insights into the beneficial effects of CR on vascular homeostasis,including reduced oxidative stress,enhanced nitric oxide(NO)bioactivity,and decreased inflammation.A number of important molecules,including sirtuins,AMP-activated protein kinase,mammalian targets of rapamycin,endothelial nitric oxidase and their regulatory pathways are involved in the maintenance of vascular homeostasis.Evidence has shown that these pathways are responsible for many aspects of CR’s effects,and that they may also mediate the effects of CR on vasculature. 展开更多
关键词 calorie restriction(CR) vascular homeostasis Sirtuin 1(SIRT1) AMP-activated protein kinase(AMPK) mammalian target of rapamycin(mTOR) endothelial nitric oxide synthase(eNOS)
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