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Improving efficiency of inverted perovskite solar cells via ethanolamine-doped PEDOT:PSS as hole transport layer 被引量:2
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作者 王子君 李嘉文 +2 位作者 张大勇 杨根杰 于军胜 《Chinese Physics B》 SCIE EI CAS CSCD 2022年第8期631-638,共8页
In order to fabricate high-performance inverted perovskite solar cells(Pe SCs), an appropriate hole transport layer(HTL) is essential since it will affect the hole extraction at perovskite/HTL interface and determine ... In order to fabricate high-performance inverted perovskite solar cells(Pe SCs), an appropriate hole transport layer(HTL) is essential since it will affect the hole extraction at perovskite/HTL interface and determine the crystallization quality of the subsequent perovskite films. Herein, a facile and simple method is developed by adding ethanolamine(ETA)into poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)(PEDOT:PSS) as HTL. The doping of a low-concentration ETA can efficiently modify the electrical properties of the PEDOT:PSS film and lower the highest occupied molecular orbital(HOMO) level, which is more suitable for the hole extraction from the perovskite to HTL. Besides, ETA-doped PEDOT:PSS will create a perovskite film with larger grain size and higher crystallinity. Hence, the results show that the open-circuit voltage of the device increases from 0.99 V to 1.06 V, and the corresponding power conversion efficiency(PCE)increases from 14.68% to 19.16%. The alkaline nature of ethanolamine greatly neutralizes the acidity of PEDOT:PSS, and plays a role in protecting the anode, leading the stability of the devices to be improved significantly. After being stored for2000 h, the PCE of ETA-doped PEDOT:PSS devices can maintain 84.2% of the initial value, which is much higher than67.1% of undoped devices. 展开更多
关键词 perovskite solar cells PEDOT:PSS ETHANOLAMINE DOPING
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Feasibility Study of Enforcing Immunization Certificate Check Before Primary School or Kindergarten Enrollment in Guizhou Province, China
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作者 LI SHENG SHU-YAN ZUO +8 位作者 JING XIE YA-LI QI YI-BING TONG GUANG-PENG TANG JUN ZHOU da-yong zhang CHANG-BING LONG WEN DU ZI-JIAN FENG 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2007年第5期357-365,共9页
Objective To study the feasibility of enforcing immunization certificate check before children enroll in primary schools or kindergartens in Guizhou Province. Methods Quantitative and qualitative studies were conducte... Objective To study the feasibility of enforcing immunization certificate check before children enroll in primary schools or kindergartens in Guizhou Province. Methods Quantitative and qualitative studies were conducted. The multi-stage and cluster sampling approach was adopted for the quantitative part of the study. A questionnaire was designed and 996 children and their keepers were interviewed. Principals, doctors or teachers of the primary schools, directors and child care nurses of kindergarten, and staff of immunization agencies were invited to take part in 12 focus group discussions; meanwhile, face-to-face individual in-depth interviews with 16 officials of the Health, Education and Governmental Departments at various levels were conducted. Results The total number of subjects was 996. 16.7% of the children in the study completed all the procedures of the National Immunization Programme. 34.3% of them had immunization certificates while the remainder 44.7% registered in immunization agencies. Factors, including the migrant children, doubt about vaccine efficiency, mother’s occupation and educational background, knowledge of the National Immunization Programme on targeted vaccines, played an important role in obtaining or not immunization certificates. 95% of the keepers interviewed thought the immunization certificates were useful; 94.8% of them considered the check was critical while only 3.6% of them thought it unnecessary. The first reason from those who found it unnecessary was that they feared that repeated immunization might affect their children’s health. The second reason was the cost of immunization, which some of them could not afford to pay. However, the Health Department expressed a favorable attitude to the checking scheme. Though the Education Department agreed that the scheme was essential, they worried that it would affect the enrollment rate. Conclusion In spite of the difficulty in 展开更多
关键词 中国 广州 幼儿园 免疫证书检查 取样
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旱区小麦植株竞争导致的公地悲剧,是源自遗传性状还是源自可塑性性状?
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作者 Li Zhu Jun Xiang +6 位作者 da-yong zhang Wei Wang Shuang-Guo Zhu Bao-Zhong Wang Li-Yuan Yang Meng-Ying Li You-Cai Xiong 《Journal of Plant Ecology》 SCIE CSCD 2023年第4期120-131,共12页
作物的生长冗余,也就是营养器官的过度生长,常常对作物产量不利,因此被称为作物的‘公地悲剧’。作物品种内相邻植株之间的资源竞争也会导致可塑性的营养器官的过度生长,因此被称为可塑性的公地悲剧。然而,目前有关这种可塑性的公地悲... 作物的生长冗余,也就是营养器官的过度生长,常常对作物产量不利,因此被称为作物的‘公地悲剧’。作物品种内相邻植株之间的资源竞争也会导致可塑性的营养器官的过度生长,因此被称为可塑性的公地悲剧。然而,目前有关这种可塑性的公地悲剧如何响应不同作物品种和不同的资源水平的研究较少。本研究设计了盆栽实验来探索这一问题。为设置根系竞争和无竞争两种处理,把同品种两个植株栽种在同一花盆中,分别用尼龙和塑料进行隔离;采用了两个小麦品种(古老品种和尚头和现代品种92-46),设置了两个资源水平处理。研究结果表明,与92-46相比,和尚头品种把资源更多地分配给茎叶,更少地分配给种子。异速生长数据显示,在24对尼龙隔离和塑料隔离处理的比较中,只有4对显示出程度很小的差异。异速生长数据还显示,相比和尚头品种,92-46品种对增加资源的响应程度更小。基于有限样本大小,本研究揭示了作物地上部分营养生长和繁殖生长之间的权衡关系。正是这种权衡关系,导致了和尚头小麦品种的‘公地悲剧’式生长,同时也使得92-46小麦品种的种子产量得以提升。小麦的公地悲剧更可能是源自遗传性状(比如古老品种的生长冗余),而不太可能是源自植株的可塑性冗余生长。现代小麦品种92-46可能采用了节约型的资源利用方式,而古老品种则采取的是消耗型策略。综上所述,本研究表明育种工作者应当选育个体竞争力低的基因型。 展开更多
关键词 根系竞争 资源分配 生长冗余 公地悲剧 权衡
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Variation in Floral Sex Allocation and Reproductive Success in Sequentially Flowering Inflorescence of Corydalis remota var. lineariloba(Fumariaceae) 被引量:6
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作者 Yan-Fei Zeng Wei-Ning Bai +1 位作者 Yu Zhou da-yong zhang 《Journal of Integrative Plant Biology》 SCIE CAS CSCD 2009年第3期299-307,共9页
In hermaphroditic plants,female reproductive success often varies among different positions within an inflorescence. However,few studies have evaluated the relative importance of underlying causes such as pollen limit... In hermaphroditic plants,female reproductive success often varies among different positions within an inflorescence. However,few studies have evaluated the relative importance of underlying causes such as pollen limitation,resource limitation or architectural effect,and few have compared male allocation. During a 2-year investigation,we found that female reproductive success of an acropetally flowering species,Corydalis remota Fisch. ex Maxim. var. lineariloba Maxim. was significantly lower in the upper late developing flowers when compared with the lower early flowers. Supplementation with outcross pollen did not improve female reproductive success of the upper flowers,while removal of the lower developing fruits significantly increased female reproductive success of the upper flowers in both years,evidencing resource limitation of the upper flowers. Female production in upper flowers was greatly improved by simultaneous pollen supplementation of the upper flowers and removal of the lower fruits,suggesting that,when resources are abundant,pollen may limit the female reproductive success of the upper flowers. The less seed mass in the upper flowers didn't increase in all treatments due to architecture. In the upper flowers,ovule production was significantly lower and the pollen :ovule ratio was significantly higher. These results suggest that male-biased sex allocation in the upper flowers may lead to increased male reproductive success,whereas the lower flowers have higher female reproductive success. 展开更多
关键词 延胡索 繁殖成功率 女性生殖系统 变种 遥感 花序 开花 发展中国家
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The rhythmic expression of genes controlling flowering time in southern and northern populations of invasive Ambrosia artemisiifolia 被引量:7
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作者 Xiao-Meng Li da-yong zhang Wan-Jin Liao 《Journal of Plant Ecology》 SCIE 2015年第2期207-212,共6页
Aims Flowering time has been suggested to be an important adaptive trait during the dispersal of invasive species,and identifying the molecu-lar mechanisms underlying flowering time may provide insight into the local ... Aims Flowering time has been suggested to be an important adaptive trait during the dispersal of invasive species,and identifying the molecu-lar mechanisms underlying flowering time may provide insight into the local adaptation during the process of invasion.Here,we con-ducted a preliminary exploration on the genetic basis of the differ-entiation of flowering time in Ambrosia artemisiifolia.Methods using relative real-time fluorescent quantitative polymerase chain reaction,we investigated the expression levels of eight flowering-related genes,including AP1,FT,SOC1,CRY2,FKF1,GI,CO2 and SPY,in leaves and flowers at different time points in individuals from northern beijing and southern Wuhan populations that exhibit significant differences in flowering times to identify any rhythmic changes in gene expression and their association with differential flowering times.Important Findings The differentiation of flowering time in the A.artemisiifolia popula-tions was closely associated with five genes involved in flowering pathways.The floral pathway integrators FT and SOC1 and floral meristem identity gene AP1 exhibited increased expression during flowering.The photoreceptor CRY2 in the light-dependent path-way and the SPY gene in the gibberellin pathway displayed specific expression patterns over time.in earlier-flowering beijing plants,CRY2 expression was lower and SPY expression was higher than in Wuhan plants.The expression patterns of these five genes sug-gest a molecular basis for the differentiation of flowering time in A.artemisiifolia. 展开更多
关键词 Ambrosia artemisiifolia flowering time adaptation flowering pathway gene expression
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Coexistence of nearly neutral species 被引量:4
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作者 Fangliang He da-yong zhang Kui Lin 《Journal of Plant Ecology》 SCIE 2012年第1期72-81,共10页
Aims The neutral theory of biodiversity provides a powerful framework for modeling macroecological patterns and interpreting species assemblages.However,there remain several unsolved problems,including the effect of r... Aims The neutral theory of biodiversity provides a powerful framework for modeling macroecological patterns and interpreting species assemblages.However,there remain several unsolved problems,including the effect of relaxing the assumption of strict neutrality to allow for empirically observed variation in vital rates and the‘problem of time’—empirically measured coexistence times are much shorter than the prediction of the strictly neutral drift model.Here,we develop a nearly neutral model that allows for differential birth and death rates of species.This model provides an approach to study species coexistence away from strict neutrality.Methods Based on Moran’s neutral model,which assumes all species in a community have the same competitive ability and have identical birth and death rates,we developed a model that includes birth–death trade-off but excludes speciation.This model describes a wide range of asymmetry from strictly neutral to nearly neutral to far from neutral and is useful for analyzing the effect of drift on species coexistence.Specifically,we analyzed the effects of the birth–death trade-off on the time and probability of species coexistence and quantified the loss of biodiversity(as measured by Simpson’s diversity)due to drift by varying species birth and death rates.Important Findings We found(i)a birth–death trade-off operating as an equalizing force driven by demographic stochasticity promotes the coexistence of nearly neutral species.Species near demographic trade-offs(i.e.fitness equivalence)can coexist even longer than that predicted by the strictly neutral model;(ii)the effect of birth rates on species coexistence is very similar to that of death rates,but their compensatory effects are not completely symmetric;(iii)ecological drift over time produces a march to fixation.Trade-off-based neutral communities lose diversity more slowly than the strictly neutral community,while non-neutral communities lose diversity much more rapidly;and(iv)nearly neutral systems have substantially shorter time of coexistence than that of neutral systems.This reduced time provides a promising solution to the problem of time. 展开更多
关键词 birth rate ecological drift death rate demographic trade-off nearly neutral theory probability of extinction time of coexistence
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Demographic trade-offs determine species abundance and diversity 被引量:4
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作者 da-yong zhang Bo-Yu zhang +5 位作者 Kui Lin Xinhua Jiang Yi Tao Stephen Hubbell Fangliang He Annette Ostling 《Journal of Plant Ecology》 SCIE 2012年第1期82-88,共7页
Aims Much recent theory has focused on the role of neutral processes in assembling communities,but the basic assumption that all species are demographically identical has found little empirical support.Here,we show th... Aims Much recent theory has focused on the role of neutral processes in assembling communities,but the basic assumption that all species are demographically identical has found little empirical support.Here,we show that the framework of the current neutral theory can easily be generalized to incorporate species differences so long as fitness equivalence among individuals is maintained through trade-offs between birth and death.Methods Our theory development is based on a careful reformulation of the Moran model of metacommunity dynamics in terms of a non-linear one-step stochastic process,which is described by a master equation.Important Findings We demonstrate how fitness equalization through demographic trade-offs can generate significant macroecological diversity patterns,leading to a very different interpretation of the relation between Fisher’s a and Hubbell’s fundamental biodiversity number.Our model shows that equal fitness(not equal demographics)significantly promotes species diversity through strong selective sieving of community membership against high-mortality species,resulting in a positive association between species abundance and per capita death rate.An important implication of demographic trade-off is that it can partly explain the excessively high speciation rates predicted by the neutral theory of the stronger symmetry.Fitness equalization through demographic trade-offs generalizes neutral theory by considering heterospecific demographic difference,thus representing a significant step toward integrating the neutral and niche paradigms of biodiversity. 展开更多
关键词 birth–death trade-off ecological drift fitness equivalence neutral theory species coexistence
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Dispersal and recruitment limitation contribute differently to community assembly 被引量:4
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作者 Zechen Peng Shurong Zhou da-yong zhang 《Journal of Plant Ecology》 SCIE 2012年第1期89-96,共8页
Aims The neutral theory of biodiversity has been criticized for being fragile with even slight deviations from its basic assumption of equal fitness among species.In response to this criticism,Hubbell((2001)The Unifie... Aims The neutral theory of biodiversity has been criticized for being fragile with even slight deviations from its basic assumption of equal fitness among species.In response to this criticism,Hubbell((2001)The Unified Neutral Theory of Biodiversity and Biogeography.Princeton,NJ:Princeton University Press)proposed that competitive exclusion can be infinitely delayed by dispersal and recruitment limitation,thus making species effectively neutral.But the theoretical foundation for this claim still remains unclear and controversial,and the effects of dispersal and recruitment limitation are often confounded,especially in field studies.This study aims to provide an affirmative theoretical answer to the question of whether dispersal limitation and recruitment limitation can separately or jointly overwhelm the effects of fitness differences among species and lead to neutral community dynamics.Methods Computer simulations were used to investigate the effects of dispersal and recruitment limitation on delaying competitive exclusion in a homogeneous habitat in a spatially explicit context.Important Findings We found that even a slight competitive asymmetry would require extremely strong dispersal and recruitment limitation for neutrality to emerge.Most importantly,when the effects of dispersal and recruitment limitation were set apart,it is found that recruitment limitation is more effective in delaying competitive exclusion,whereas dispersal limitation tends to have a stronger impact on the general shape of both species abundance distributions and species–area relationships. 展开更多
关键词 COMMUNITY DIVERSITY neutral theory SAD SAR
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The functional significance of a stigma color polymorphism in Acer pictum subsp. mono (aceraceae) 被引量:4
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作者 Zhi-Qun Yang da-yong zhang Wei-Ning Bai 《Journal of Plant Ecology》 SCIE 2015年第2期166-172,共7页
Aims Exploring the characteristics and function of a flower color poly-morphism contributes to our understanding of floral evolution in angiosperms.However,little information is available on stigma color polymorphisms... Aims Exploring the characteristics and function of a flower color poly-morphism contributes to our understanding of floral evolution in angiosperms.However,little information is available on stigma color polymorphisms in flowering plants despite their important functional role in plant reproduction.Methods We studied a stigma color polymorphism at the individual level in Acer pictum subsp.mono(aka A.mono)by investigating stigma-color morph proportion and comparing stigma performance and compo-nents of female fitness(pollen adhesion,pollen germination,fruit set,seed set and fruit weight)between the two morphs(red and greenish-yellow stigma)within natural populations at Dongling mountain in the north of China.in the flowering period,we conducted hand pol-lination in natural populations and then made microscopic observa-tions using the aniline blue fluorescence method.Important Findingsindividuals in the studied populations did not change their stigma color between years,and flowers produced by a single tree were uniform in their stigma color.This strongly suggests that stigma color variation is genetically controlled.The percentage of the red stigma flowers with germinated pollen grains was significantly higher than that of the greenish-yellow stigma flowers when hand pollination was conducted in the early flowering period,but not so in the late flowering period.There was no significant difference in the percentage of flowers with pollen adhesion to the stigma between the two morphs.Fruit set of the red morph was signifi-cantly higher than that of the greenish-yellow morph.our findings suggest that the red morph may be more advantageous for pollen germination and fruit set than the greenish-yellow morph,which may provide a functional explanation for the high incidence of the red stigma morph in the studied populations.alternative explana-tions for the stigma color polymorphism are discussed to stimulate further work. 展开更多
关键词 ACER female fitness stigma color polymorphism stigma performance
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纬度变异对欧洲千里光原产地与引入地种群野外和同质生物园比较的影响
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作者 Bi-Ru Zhu Xiao-Meng Li +1 位作者 da-yong zhang Wan-Jin Liao 《Journal of Plant Ecology》 SCIE CSCD 2021年第3期414-424,共11页
野外和同质生物园比较经常用于研究入侵植物快速进化。当原产地或引入地的种群地理分布范围较广时,表型性状的纬度渐变可能会影响这种比较分析。我们检验了纬度渐变是否会影响欧洲千里光(5enec/owv/gara)引入地和原产地种群间的比较。... 野外和同质生物园比较经常用于研究入侵植物快速进化。当原产地或引入地的种群地理分布范围较广时,表型性状的纬度渐变可能会影响这种比较分析。我们检验了纬度渐变是否会影响欧洲千里光(5enec/owv/gara)引入地和原产地种群间的比较。欧洲千里光原产于欧洲,现己引入到中国东北和西南地区。我们对欧洲原产地和中国引入地的野外种群进行了调查,同时在瑞士开展了同质生物园实验,比较了中国引入地种群与欧洲原产地种群的株高、分枝数和花序数,以此衡量两地欧洲千里光种群在生长和繁殖方面的差异。野外调查表明,中国引入地种群的株高和花序数量显著大于欧洲原产地种群,这一结果与增强竞争力进化假说的预测一致。在同质生物园比较中,当考虑纬度渐变的作用时,中国种群的花序数量显著大于欧洲种群。分别将中国东北部、中国西南部两个地区的种群与欧洲种群进行比较,无论在野外还是同质生物园,与欧洲种群处于相似纬度的中国东北部种群表现出更高的株高和更多的花序。但位于更低纬度的中国西南部种群的繁殖表现并不强于原产地种群。因此我们的结果表明,当引入地种群地理分布较广时,无论野外还是同质生物园的比较都应该考虑表型性状纬度渐变的影响。 展开更多
关键词 .•同质生物园 增强竞争力进化假说 生境生产力 入侵 纬度渐变
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The multitude of biodiversity: methods, theories and applications
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作者 Shixiao Yu da-yong zhang Fangliang He 《Journal of Plant Ecology》 SCIE 2012年第1期1-2,共2页
Arguably,no subject in ecology is as broad and inclusive,yet fundamental,as biodiversity.The diverse facets of biodiversity are reflected by the plethora of its definitions,measurements,maintenance theories and manage... Arguably,no subject in ecology is as broad and inclusive,yet fundamental,as biodiversity.The diverse facets of biodiversity are reflected by the plethora of its definitions,measurements,maintenance theories and management practices across spatial and temporal scales.In May 2011,we held a symposium for Theoretical Ecology and Biodiversity in Guangzhou,China,to showcase just that multitude of biodiversity.The symposium was sponsored by the State Key Laboratory of Biocontrol,Sun Yat-sen University and University of Alberta.We sought to achieve three goals.The first was to provide a venue to present and exchange the state of the art of biodiversity science.The second was to establish mentoring relationships by connecting a group of young ecologists to the internationally renowned scientists who were invited to attend the symposium.This special issue is the third goal we have accomplished. 展开更多
关键词 connecting SYMPOSIUM GUANGZHOU
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