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基于厚尾噪声分布的重介质分选密度辨识
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作者 梁旭 贺亚飞 王宇 《选煤技术》 CAS 2024年第3期17-23,共7页
为解决重介质选煤过程中分选密度识别易受厚尾噪声污染的问题,建立了ARX分选密度辨识模型,并利用学生式t分布建模了密度辨识系统中的厚尾噪声,而后采用期望最大化(EM)算法将厚尾噪声识别问题公式化,最后通过仿真模拟对密度及厚尾噪声辨... 为解决重介质选煤过程中分选密度识别易受厚尾噪声污染的问题,建立了ARX分选密度辨识模型,并利用学生式t分布建模了密度辨识系统中的厚尾噪声,而后采用期望最大化(EM)算法将厚尾噪声识别问题公式化,最后通过仿真模拟对密度及厚尾噪声辨识模型进行了验证。结果表明:用于厚尾噪声识别的EM算法与传统极大似然估计算法(MLE)相比,可有效处理隐含变量或数据丢失问题,相应偏差范数(BN)和方差范数(VN)也均低于后者,具有更佳的鲁棒性;所估计的模型参数在有限次数迭代下即可收敛于真实值附近,算法处理厚尾噪声有效。研究结果可一定程度上提升重介质选煤过程中重悬浮液密度自动检测的准确性。 展开更多
关键词 重介质选煤 分选密度辨识 厚尾噪声污染 ARX模型 学生式t分布 期望最大化算法 鲁棒性
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Adapting Grice's maxims in the teaching of writing
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作者 杨军 《海外英语》 2011年第11X期354-355,369,共3页
Grice's maxims,which define the conditions for efficient spoken communication,can be adapted to the teaching of writing by providing both teachers and writers with a way of understanding successful and unsuccessfu... Grice's maxims,which define the conditions for efficient spoken communication,can be adapted to the teaching of writing by providing both teachers and writers with a way of understanding successful and unsuccessful written correspondence in mono-and cross-cultural settings.A survey of lay readers' responses to a sample letter which show that,while there are individual differences in the way these maxims are interpreted,readers expect clarity,brevity,and sincerity,and writing which fails to meet these expectations will be unfavorably received.Also discussed are the issues of contrastive rhetoric,and ways of helping writers to position themselves in relation to their real or imagined reader. 展开更多
关键词 Grice’s maxims quality quantity RELATION MANNER
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Polyploidy Induction of Pteroceltis tatarinowii Maxim. 被引量:2
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作者 Lin ZHANG Feng WANG +2 位作者 Zhongkui SUN Cuicui ZHU Rongwei CHEN 《Agricultural Science & Technology》 CAS 2015年第6期1159-1161,共3页
[Objective] This study was conducted to obtain tetraploid Pteroceltis tatar# nowii Maxim. with excellent ornamental traits. [Method] The stem apex growing points of Pteroceltis tatarinowii Maxim. were treated with dif... [Objective] This study was conducted to obtain tetraploid Pteroceltis tatar# nowii Maxim. with excellent ornamental traits. [Method] The stem apex growing points of Pteroceltis tatarinowii Maxim. were treated with different concentrations of colchicine solution for different hours to figure out a proper method and obtain poly- ploids. [Result] The most effective induction was obtained by treatment with 0.6%- 0.8% colchicine for 72 h with 34.2% mutation rate. Flow cytometry and chromosome observation of the stem apex growing point of P. tatarinowii Maxim. proved that the tetraploid plants were successfully obtained with chromosome number 2n=4x=36. [Conclusion] The result not only fills the blank of polyploid breeding of P. tatarinowii, but also provides an effective way to broaden the methods of cultivation of fast- growing, high-quality, disease-resilience, new varieties of Pteroceltis. 展开更多
关键词 Pteroceltis tatarinowii maxim. TETRAPLOID COLCHICINE
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Trillium tschonoskii maxim extract attenuates abnormal Tau phosphorylation 被引量:4
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作者 Hong-Bin Luo Nan Shang +10 位作者 Wen-Zhi Xie De-Jian Wen Min Qu Sheng Huang Sha-Sha Fan Wei Chen Nan-Qiao Mou Xiang-Yu Liu Qin Chen Feng-Feng Xie Jun-Xu Li 《Neural Regeneration Research》 SCIE CAS CSCD 2018年第5期915-922,共8页
Large-scale epidemiological studies have found that hyperhomocysteinemia is a powerful, independent risk factor for Alzheimer's disease. Trillium tschonoskii maxim is a traditional Chinese medicine that is used to pr... Large-scale epidemiological studies have found that hyperhomocysteinemia is a powerful, independent risk factor for Alzheimer's disease. Trillium tschonoskii maxim is a traditional Chinese medicine that is used to promote memory. However, scientific understanding of its mechanism of action is limited. This report studied the potential neuroprotective effects of Trillium tschonoskii maxim extract against homocysteine-induced cognitive deficits. Rats were intravenously injected with homocysteine(400 μg/kg) for 14 days to induce a model of Alzheimer's disease. These rats were then intragastrically treated with Trillium tschonoskii maxim extract(0.125 or 0.25 g/kg) for 7 consecutive days. Open field test and Morris water maze test were conducted to measure spontaneous activity and learning and memory abilities. Western blot assay was used to detect the levels of Tau protein and other factors involved in Tau phosphorylation in the hippocampus. Immunohistochemical staining was used to examine Tau protein in the hippocampus. Golgi staining was applied to measure hippocampal dendritic spines. Our results demonstrated that homocysteine produced learning and memory deficits and increased levels of Tau phosphorylation, and diminished the activity of catalytic protein phosphatase 2A. The total number of hippocampal dendritic spines was also decreased. Trillium tschonoskii maxim extract treatment reversed the homocysteine-induced changes. The above results suggest that Trillium tschonoskii maxim extract can lessen homocysteine-induced abnormal Tau phosphorylation and improve cognitive deterioration such as that present in Alzheimer's disease. 展开更多
关键词 nerve regeneration Trillium tschonoskii maxim HOMOCYSTEINE Alzheimer's disease cognitive disorders TAU synaptic development neural regeneration
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On s*-Completions of Maximal Subgroups of Finite Groups 被引量:1
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作者 高辉 高胜哲 尹丽 《Chinese Quarterly Journal of Mathematics》 2015年第3期381-388,共8页
Given a maximal subgroup M of a group G, a θ*-completion C of M is called an s*-completion if either C = G or there exists a subgroup D of G which is not a θ*-completion of M such that D contains C as a maximal subg... Given a maximal subgroup M of a group G, a θ*-completion C of M is called an s*-completion if either C = G or there exists a subgroup D of G which is not a θ*-completion of M such that D contains C as a maximal subgroup. In this paper, we obtain several results on s*-completions which imply G to be solvable or supersolvable. 展开更多
关键词 maximAL SUBGROUPS θ*-completions s*-completions SOLVABLE GROUPS super-solvable GROUPS
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DOOB’S MAXIMAL INEQUALITIES FOR MARTINGALES IN VARIABLE LEBESGUE SPACE 被引量:1
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作者 Peide LIU 《Acta Mathematica Scientia》 SCIE CSCD 2021年第1期283-296,共14页
In this paper we deal with the martingales in variable Lebesgue space over a probability space.We first prove several basic inequalities for conditional expectation operators and give several norm convergence conditio... In this paper we deal with the martingales in variable Lebesgue space over a probability space.We first prove several basic inequalities for conditional expectation operators and give several norm convergence conditions for martingales in variable Lebesgue space.The main aim of this paper is to investigate the boundedness of weak-type and strong-type Doob’s maximal operators in martingale Lebesgue space with a variable exponent.In particular,we present two kinds of weak-type Doob’s maximal inequalities and some necessary and sufficient conditions for strong-type Doob’s maximal inequalities.Finally,we provide two counterexamples to show that the strong-type inequality does not hold in general variable Lebesgue spaces with p>1. 展开更多
关键词 variable Lebesgue space martingale inequality norm convergence Doob’s maximal inequality
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Preliminary Research on Radiation Breeding of Pteroceltis tatarinowii Maxim.
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作者 Chengxiu LI Tiantian CHENG +2 位作者 Zhongkui SUN Yu YAN Lin ZHANG 《Agricultural Biotechnology》 CAS 2021年第6期14-15,18,共3页
In order to explore the effect of radiation breeding on new germplasm innovation of Pteroceltis tatarinowii,the dry seeds of P.tatarinowii from Lingyan Temple were used as test materials in this study,which were irrad... In order to explore the effect of radiation breeding on new germplasm innovation of Pteroceltis tatarinowii,the dry seeds of P.tatarinowii from Lingyan Temple were used as test materials in this study,which were irradiated by ^(60)Co-γ rays with different radiation doses.The results showed that the emergence rate decreased with the increase of radiation dose,the emergence rate of low dose below 200 Gy decreased slowly,and the emergence rate of high dose above 200 Gy decreased sharply;when the radiation dose ranged from 100 to 200 Gy,the mutagenic effect of P.tatarinowii seeds was the best;and radiation obviously affected the leaf color and leaf shape of seedlings.This study provides original materials for the cultivation of new P.tatarinowii varieties and the study of color-changing mechanism. 展开更多
关键词 Pteroceltis tatarinowii maxim. ^(60)Co-γradiation Seedling emergence
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Maxim推出HDMI v1.3、2.25 Gb/s自动电缆均衡器
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《电子技术应用》 北大核心 2010年第3期96-96,共1页
Maxim推出用于HDMIv1.3TMDS应用的2.25Gb/s自动电缆均衡器MAX3815A。MAX3815A可补偿0-35m的24AWGHDMI电缆,或0-22in的28AWGHDMI电缆,能够运行速率高达2.25Gb/s的TMDS数据。器件兼容720P、1080i、1080P以及30-36位色彩(“深色”... Maxim推出用于HDMIv1.3TMDS应用的2.25Gb/s自动电缆均衡器MAX3815A。MAX3815A可补偿0-35m的24AWGHDMI电缆,或0-22in的28AWGHDMI电缆,能够运行速率高达2.25Gb/s的TMDS数据。器件兼容720P、1080i、1080P以及30-36位色彩(“深色”)的1080pHDTV分辨率。器件还支持VGA至WUXGA计算机分辨率。 展开更多
关键词 maxim MI电缆 B/S 均衡器 HDMI 1080i TMDS 运行速率
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Cohomology of Weakly Reducible Maximal Triangular Algebras
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作者 董浙 鲁世杰 《Northeastern Mathematical Journal》 CSCD 2000年第3期299-306,共8页
In this paper, we introduce the concept of weakly reducible maxi mal triangular algebras S*!which form a large class of maximal t riangular algebras. Let B be a weakly closed algebra containing S, we prove that the co... In this paper, we introduce the concept of weakly reducible maxi mal triangular algebras S*!which form a large class of maximal t riangular algebras. Let B be a weakly closed algebra containing S, we prove that the cohomology spaces Hn(S , B) ( n≥1) are trivial. 展开更多
关键词 weakly reducible maximal triangular algebra cohomology s pace
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Maxim推出独立式4通道线性均衡器
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《电子技术应用》 北大核心 2009年第9期94-94,共1页
Maxim推出用于铜缆互联应用的1Gb/s~10.3Gb/s、4通道线性均衡器MAX3986。该器件为高性能、独立式均衡器,具有业内最佳的端口匹配(典型回波损耗为24dB)和通道间隔离(33dB,典型值)。每通道能够补偿20英寸FR4电缆的损耗,数据速... Maxim推出用于铜缆互联应用的1Gb/s~10.3Gb/s、4通道线性均衡器MAX3986。该器件为高性能、独立式均衡器,具有业内最佳的端口匹配(典型回波损耗为24dB)和通道间隔离(33dB,典型值)。每通道能够补偿20英寸FR4电缆的损耗,数据速率高达10.3Gb/s。此外,MAX3986是业内首款独立式均衡器,能够用于扩展通常集成在串行器,解串器(SerDes)和ASIC中的限幅均衡器和判决反馈均衡器(DFE)的范围。 展开更多
关键词 线性均衡器 maxim 通道间隔 立式 判决反馈均衡器 回波损耗 B/S 20英寸
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The Project “Development and Application of FCC Additive for Maximization of Propylene and Isobutylene” Passed SINOPEC's Appraisal
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《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2014年第1期70-70,共1页
The research project'Development and application of FCC additive for maximization of propylene and isobutylene'jointly undertaken by RIPP,the Baling Petrochemical Company(BPC)and the SINOPEC
关键词 FCC Development and Application of FCC Additive for maximization of Propylene and Isobutylene Passed SINOPEC’s Appraisal The Project
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Drude, Hall and Maximal Conductivities: A Unified Complex Model
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作者 Arbab I. Arbab 《Journal of Modern Physics》 2012年第9期1040-1045,共6页
By adopting a complex formulation of Ohm’s law, we arrive at combined equations connecting the conductivities of conductors. The horizontal resistivity is equal to the inverse of Drude’s conductivity δo( ), and the... By adopting a complex formulation of Ohm’s law, we arrive at combined equations connecting the conductivities of conductors. The horizontal resistivity is equal to the inverse of Drude’s conductivity δo( ), and the vertical resistivity (ρy) is equal to the Hall’s conductivity ( δH). At high magnetic field, the horizontal conductivity becomes exceedingly small, whereas the vertical conductivity equals to Hall’s conductivity. The Hall’s conductivity is shown to represent the maximal conductivity of conductors. Drude’s and Hall’s conductivities are related by δo =δHωC , where ωC is the cyclotron frequency, and is the relaxation time. The quantization of Hall’s conductivity is attributed to the fact that the magnetic flux enclosed by the conductor is carried by electrons each with h/e, where h is the Planck’s constant and e is the electron’s charge. The Drude’s conductance is found to be equal to Hall's conductance provided the magnetic flux enclosed by the conductor is a multiple of h/e. 展开更多
关键词 Drude’s CONDUCTIVITY Hall’s CONDUCTIVITY maximAL CONDUCTIVITY UNIFIED CONDUCTIVITIES
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Stability and stabilization of discrete T-S fuzzy time-delay system based on maximal overlapped-rules group 被引量:1
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作者 Songtao Zhang Xiaowei Zhao Jiantong Zhang 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2016年第1期201-210,共10页
The problems of stability and stabilization for the discrete Takagi-Sugeno(T-S) fuzzy time-delay system are investigated.By constructing a discrete piecewise Lyapunov-Krasovskii function(PLKF) in each maximal over... The problems of stability and stabilization for the discrete Takagi-Sugeno(T-S) fuzzy time-delay system are investigated.By constructing a discrete piecewise Lyapunov-Krasovskii function(PLKF) in each maximal overlapped-rules group(MORG),a new sufficient stability condition for the open-loop discrete T-S fuzzy time-delay system is proposed and proved.Then the systematic design of the fuzzy controller is investigated via the parallel distributed compensation control scheme,and a new stabilization condition for the closed-loop discrete T-S fuzzy time-delay system is proposed.The above two sufficient conditions only require finding common matrices in each MORG.Compared with the common Lyapunov-Krasovskii function(CLKF) approach and the fuzzy Lyapunov-Krasovskii function(FLKF) approach,these proposed sufficient conditions can not only overcome the defect of finding common matrices in the whole feasible region but also largely reduce the number of linear matrix inequalities to be solved.Finally,simulation examples show that the proposed PLKF approach is effective. 展开更多
关键词 stability analysis maximal overlapped-rules group(MORG) Takagi-Sugeno(T-S)fuzzy model discrete time-delay system piecewise Lyapunov-Krasovskii function(PLKF).
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我国代孕子女监护权确认问题研究 被引量:1
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作者 黄晓林 张钰扬 《青岛农业大学学报(社会科学版)》 2023年第1期67-72,99,共7页
代孕在我国系违法行为,但自代孕子女出生的事实确定那一刻起,其已经属于应享有权利并承担义务的自然人。我国现行立法无法满足代孕子女监护权的保障,且司法实践、现实需求与立法的绝对禁止冲突严重,究其原因是缺乏统一法律规范,且未就... 代孕在我国系违法行为,但自代孕子女出生的事实确定那一刻起,其已经属于应享有权利并承担义务的自然人。我国现行立法无法满足代孕子女监护权的保障,且司法实践、现实需求与立法的绝对禁止冲突严重,究其原因是缺乏统一法律规范,且未就理论达成共识。根据《中华人民共和国民法典》相关规定非婚生子女与婚生子女享有同等权利,代孕子女也应类推解释,基于未成年子女利益最大化原则明晰其监护权判定,并制定配套管理制度,考量核心家庭维护、阶段监护等因素保障其相关权利。 展开更多
关键词 代孕子女监护权 亲子关系 子女利益最大化
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淫羊藿激活CREB/BDNF信号通路改善APP/PS1双转基因小鼠的认知功能 被引量:1
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作者 崔琳 肖洪贺 +4 位作者 李贺 田雨 田晋明 赵宇萌 杨静娴 《药学研究》 CAS 2023年第6期361-366,共6页
目的研究淫羊藿能否通过调节环磷酸腺苷效应元件结合蛋白(cAMP response element binding protein,CREB)/脑源性神经营养因子(brain-derived neurotrophic factor,BDNF)信号通路改善APP/PS1双转基因小鼠的认知功能。方法取7月龄雄性APP/... 目的研究淫羊藿能否通过调节环磷酸腺苷效应元件结合蛋白(cAMP response element binding protein,CREB)/脑源性神经营养因子(brain-derived neurotrophic factor,BDNF)信号通路改善APP/PS1双转基因小鼠的认知功能。方法取7月龄雄性APP/PS1双转基因小鼠30只,按体重随机分为模型对照组和淫羊藿组,每组15只;另取15只同龄的雄性C57BL/6小鼠作为空白对照组。淫羊藿组灌胃给予3 g·kg^(-1)的药物溶液,空白组和模型组给予等体积0.3%CMC-Na,连续灌胃给药28 d,每天1次。筑巢试验检测小鼠日常生活能力;Morris水迷宫试验检测小鼠的学习和记忆能力;苏木素-伊红(H&E)和尼氏(Nissl)染色法观察小鼠脑组织病理学变化;采用TBA法、羟胺法检测小鼠脑组织中丙二醛(malondialdehyde,MDA)和超氧化物歧化酶(superoxide dismutase,SOD)的水平;免疫荧光化学法检测小鼠脑内β-淀粉样蛋白(amyloidβ-protein,Aβ)的表达情况;Western blot法检测环磷酸腺苷效应元件结合蛋白(cAMP response element binding protein,CREB)和脑源性神经营养因子(brain-derived neurotrophic factor,BDNF)信号通路相关蛋白的表达情况。结果与空白组比较,APP/PS1双转基因小鼠的筑巢得分明显降低,逃避潜伏期和游泳距离明显增加(P<0.01),目标象限停留时间和穿越平台次数显著减少;皮层和海马存在明显的神经病理损伤。此外,APP/PS1双转基因小鼠的皮层和海马区域可观察到大量Aβ沉积,并且脑组织中超氧化物歧化酶活性降低,丙二醛水平升高。Western blot结果显示,模型组小鼠脑内环磷酸腺苷效应元件结合蛋白蛋白磷酸化受到抑制,伴随着脑源性神经营养因子蛋白表达明显降低。淫羊藿(3 g·kg^(-1))连续灌胃4周,可明显改善模型小鼠的筑巢能力和认知功能,减轻神经病理损伤,抑制Aβ沉积,减轻氧化应激,促进环磷酸腺苷效应元件结合蛋白环磷酸腺苷效应元件结合蛋白磷酸化,增加脑源性神经营养因子蛋白表达。结论淫羊藿可明显改善APP/PS1双转基因小鼠的认知功能和神经病理损伤,其作用机制可能与激活环磷酸腺苷效应元件结合蛋白/脑源性神经营养因子信号通路有关。 展开更多
关键词 阿尔茨海默病 淫羊藿 APP/PS1双转基因小鼠 环磷酸腺苷效应元件结合蛋白/脑源性神经营养因子信号通路 认知功能
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Wielandt定理与非幂零极大子群指数皆为素数的有限群
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作者 田云凤 史江涛 刘文静 《哈尔滨理工大学学报》 CAS 北大核心 2023年第3期140-143,共4页
为了进一步研究每个非幂零极大子群的指数皆为素数的有限群的可解性,使用反证法和极小阶反例的方法,并结合应用Wielandt给出的一个关于具有幂零Hall-子群(不是Sylow-子群)的有限群G的结构刻画的定理,得到了一个较为初等的关于每个非幂... 为了进一步研究每个非幂零极大子群的指数皆为素数的有限群的可解性,使用反证法和极小阶反例的方法,并结合应用Wielandt给出的一个关于具有幂零Hall-子群(不是Sylow-子群)的有限群G的结构刻画的定理,得到了一个较为初等的关于每个非幂零极大子群的指数皆为素数的有限群G的可解性的证明。该证明没有应用Glauberman-Thompson p-幂零准则和Rose的关于具有幂零极大子群的非交换单群的分类和关于具有幂零极大子群且中心等于1的非可解群的刻画,这改进了之前在相关的研究文献中关于这个结论的证明。 展开更多
关键词 Wielandt定理 非幂零极大子群 指数 素数 可解
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水分胁迫对华北景天叶片结构和叶绿素含量的影响 被引量:11
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作者 那冬晨 王文斗 +3 位作者 杨丽静 张婧 任彩琴 柴婷婷 《安徽农业科学》 CAS 北大核心 2011年第26期15902-15903,15912,共3页
[目的]研究水分胁迫对华北景天(Sedum tatarinowii Maxim)叶片结构和叶绿素含量的影响,为其更广泛应用提供参考。[方法]取山西省霍山七里峪国家森林公园的野生华北景天,经过人工栽培后进行水分胁迫。试验共设4组,土壤绝对含水量分别为17... [目的]研究水分胁迫对华北景天(Sedum tatarinowii Maxim)叶片结构和叶绿素含量的影响,为其更广泛应用提供参考。[方法]取山西省霍山七里峪国家森林公园的野生华北景天,经过人工栽培后进行水分胁迫。试验共设4组,土壤绝对含水量分别为17.50%、13.60%、9.60%、6.20%,以土壤绝对含水量17.50%为对照。土壤绝对含水量采用烘干称重法测定;叶片中叶绿素含量采用丙酮浸提法测定;取生长良好、洁净的叶片,制备石蜡切片和表皮制片,观察气孔器类型和分布特征,测定气孔密度。[结果]在正常条件下,华北景天叶片表面具薄的蜡质层,叶内有发达的储水组织,并分布有吸水能力较强的异细胞;气孔白天关闭,夜晚开启,气孔器下陷;水分胁迫下,上表皮出现了发育不完全的气孔,成熟气孔密度呈下降趋势,下表皮气孔密度变化不明显。华北景天叶绿素a、b对活性氧的反应差异不明显,而且在一定程度的干旱条件下叶绿素含量有所增加;土壤绝对含水量为9.60%时,华北景天可维持正常光合作用;当土壤绝对含水量下降到6.20%时,叶绿素含量有所下降。[结论]华北景天具有典型的旱生植物形态特征,在较低的土壤绝对含水量时,叶绿素含量可保持不变或稳定增加的趋势,维持植物正常光合作用。 展开更多
关键词 华北景天 水分胁迫 叶片结构 叶绿素含量
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经营措施对青檀人工林生物量及檀皮产量的影响 被引量:25
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作者 方升佐 李光友 +1 位作者 李同顺 惠超 《植物资源与环境学报》 CAS CSCD 2001年第1期21-24,共4页
调查了青檀 (PteroceltistatarinowiiMaxim .)人工林不同经营措施对林分地上部分生物生产力及檀皮产量的影响。结果表明 :(1)在密度及墩龄相同条件下 ,单位面积檀皮产量与年龄成正比 ,出皮率与年龄成反比 ;(2 )单位面积檀皮产量年增长以... 调查了青檀 (PteroceltistatarinowiiMaxim .)人工林不同经营措施对林分地上部分生物生产力及檀皮产量的影响。结果表明 :(1)在密度及墩龄相同条件下 ,单位面积檀皮产量与年龄成正比 ,出皮率与年龄成反比 ;(2 )单位面积檀皮产量年增长以第 3年为最高 ,分别是第 2年和第 4年年增长量的 1 5 8倍和 4 12倍 ;(3)在密度、留萌数及萌发年龄相同条件下 ,单位面积檀皮产量以条墩年龄 12年为最高 ,分别是 6年生和 9年生的 3 32倍和 1 11倍 ;(4)四种造林密度类型 (2 5 0 0、3333、42 0 0和 5 35 0墩 hm2 )中 ,檀皮产量大小顺序为 42 0 0 >3333>5 35 0 >2 5 0 0。 42 0 0墩 hm2 (株行距 1.4m× 1 7m)的林分檀皮产量是 2 5 0 0墩 hm2 (株行距 2m× 2m)林分檀皮产量的 1 6 8倍 ;(5 )在密度、墩龄相同条件下 ,每墩留萌数为 10时 ,单位面积檀皮产量最高。从收获经济生物量 (檀皮 )的角度考虑 ,青檀人工林密度应在 3333~ 42 0 0墩 hm2 之间 ,轮伐期为 3年 ;在条墩年龄为 9年以上的人工林中 ,留萌数以 10条为好。 展开更多
关键词 青檀 人工林 生物生产力 檀皮产量 经营措施
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青檀种子休眠机理及发芽条件的探讨 被引量:45
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作者 洑香香 方升佐 杜艳 《植物资源与环境学报》 CAS CSCD 2002年第1期9-13,共5页
对青檀 (PteroceltistatarinowiiMaxim .)种子的休眠机理和发芽条件进行了探讨。共设定 5个处理 :剪破种皮、热水处理 (4 0、5 0、6 0和 70℃ )、剪破种皮并变温层积 (0~ 4℃ 16h与 10~ 15℃ 8h)、低温层积 (0~ 4℃ )和变温层积(0~ ... 对青檀 (PteroceltistatarinowiiMaxim .)种子的休眠机理和发芽条件进行了探讨。共设定 5个处理 :剪破种皮、热水处理 (4 0、5 0、6 0和 70℃ )、剪破种皮并变温层积 (0~ 4℃ 16h与 10~ 15℃ 8h)、低温层积 (0~ 4℃ )和变温层积(0~ 4℃ 16h与 10~ 15℃ 8h)。结果表明 ,剪破种皮、剪破种皮并变温层积和热水处理与对照的发芽率均无显著差异 ,说明青檀种子的休眠不是种皮限制所引起的。低温层积和变温层积处理均能打破种子的休眠 ,因而认为青檀种子休眠属于生理休眠。低温层积以 70d为最好 ,发芽率和发芽势分别达 6 7%和 5 5 % ;变温层积以 40d处理效果最好 ,发芽率和发芽势分别达 77%和 5 7%。同时还讨论了 展开更多
关键词 青檀种子 休眠机理 发芽 低温层积 变温层积
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濒危植物青檀的群落类型分析 被引量:6
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作者 陈一锟 程寅瑞 +3 位作者 黎娇华 张慧 陆畅 张小平 《生物学杂志》 CAS CSCD 2011年第6期1-5,共5页
青檀是中国特有的珍稀树种,具有很高的经济价值。以中国12个省市的19个野生青檀种群作为研究对象,分析了各生长地的气温、降水和光照条件,pH值及土壤的钙含量。并在此基础上,结合各地区青檀林中的物种情况,对青檀林植物群落类型进... 青檀是中国特有的珍稀树种,具有很高的经济价值。以中国12个省市的19个野生青檀种群作为研究对象,分析了各生长地的气温、降水和光照条件,pH值及土壤的钙含量。并在此基础上,结合各地区青檀林中的物种情况,对青檀林植物群落类型进行了划分。研究结果表明,在温带半干旱地区,年平均气温约5-12%、年平均降水量约500mm、年日照时数局部超过2500h,土壤钙含量约5000mg/kg,土壤偏碱性,该地区青檀林多为青檀一金银木一卫矛植物群落;在温带季风区年平均气温约11℃、年平均降水量约600mm、年日照时数均超过2500h。局部地区土壤钙含量最高可达10000mg/kg,土壤呈碱性,该地区青檀林多为青檀一柘树植物群落;亚热带季风区中部及北部,年平均气温约16℃、年平均降水量约1200mm、年日照时教约2000h,局部地区土壤钙含量超过5000mg/kg,土壤pH值在5.2~7.9之间,该地区青檀林多为青檀-栾树-荩草植物群落;在亚热带季风区南部,年平均气温约19℃、年平均降水量约2000mm、年日照时数低于2000h,局部地区土壤钙含量普遍超过10000mg/kg,考察点土壤呈碱性,该地区青檀林多为青檀一密花树一金钱草植物群落。可以看出,不同地区青檀的群落类型有所不同。 展开更多
关键词 青檀 气候 土壤 群落
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