期刊文献+
共找到3,305篇文章
< 1 2 166 >
每页显示 20 50 100
Eco-physiological characteristics of Tetracentron sinense Oliv.saplings in response to different light intensities
1
作者 Rong Wang Xueheng Lu +4 位作者 Hongyan Han Xuemei Zhang Yonghong Ma Qinsong Liu Xiaohong Gan 《Journal of Forestry Research》 SCIE EI CAS CSCD 2024年第3期29-44,共16页
The regeneration of Tetracentron sinense Oliv.is poor in the understory and in open areas due to the charac-teristics of natural regeneration of the species on forest edges and in gaps.It is unclear whether different ... The regeneration of Tetracentron sinense Oliv.is poor in the understory and in open areas due to the charac-teristics of natural regeneration of the species on forest edges and in gaps.It is unclear whether different light intensities in various habitats affect eco-physiological characteristics of saplings and their natural regeneration.In this study,the light intensity in T.sinense habitats was simulated by artificial shading(L1:100%NS(natural sunlight)in the open;L2:50%NS in a forest gap or edge;L3:10%NS in understory)to investigate differences in morphology,leaf structure,physiology,and photosynthesis of 2-year-old sap-lings,and to analyze the mechanism of light intensity on sapling establishment.Significant differences were observed in morphology(including leaf area,and specific leaf area)under different light intensities.Compared to L1 and L3,chloroplast structure in L2 was intact.With increasing time,superoxide dismutase(SOD)and catalase(CAT)activities in L2 became gradually higher than under the other light intensities,while malondialdehyde(MDA)content was opposite.Shading decreased osmoregulation substance contents of leaves but increased chlorophyll.The results suggest that light intensities significantly affect the eco-physiological characteristics of T.sinense saplings and they would respond most favorably at intermediate levels of light by optimizing eco-physiological characteristics.Therefore,50%natural sunlight should be created to promote saplings establishment and population recovery of T.sinense during in situ conservation,including sowing mature seeds in forest edges or gaps and providing appropriate shade protection for seedlings and saplings in the open. 展开更多
关键词 Chloroplast ultrastructure Eco-physiological characteristics Light intensities Sapling establishment Tetracentron sinense Oliv
下载PDF
L-shell x-ray fluorescence relative intensities for elements with 62≤Z≤83 at 18 keV and 23 keV by synchrotron radiation
2
作者 M Alqadi S AL-Humaidi +1 位作者 H Alkhateeb F Alzoubi 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第8期270-273,共4页
The relative intensities of L-subshell x-ray fluorescence(XRF)for elements with atomic numbers 62≤Z≤83 were measured at two excitation energies,18 keV and 23 keV,using a synchrotron radiation source at a beamline of... The relative intensities of L-subshell x-ray fluorescence(XRF)for elements with atomic numbers 62≤Z≤83 were measured at two excitation energies,18 keV and 23 keV,using a synchrotron radiation source at a beamline of the Synchrotron Light Center for Experimental Science and Applications in the Middle East(SESAME),Jordan.The experimentally measured results of the relative intensities were compared with the calculated results using the subshell fluorescence yield and the Coster-Kronig transition probabilities recommended by Campbell and the values based on the Dirac-Hartree-Slater model by Puri.The experimental and theoretical results are in agreement.In this work,L XRF relative intensities for the elements Sm,Gd,Tb,Er,Ta,W,Re,Hg,Pb and Bi at energies of 18 keV and 23 keV were measured. 展开更多
关键词 L shell x-ray fluorescence(XRF) relative intensities synchrotron radiation
下载PDF
Germination Characteristics and Secondary Metabolism Regulation of Scutellaria baicalensis Georgi Seeds under Different Light Intensities 被引量:2
3
作者 孙兆伟 刘金花 +1 位作者 李佳 张永清 《Agricultural Science & Technology》 CAS 2013年第6期842-846,共5页
[Objective] This study aimed to investigate the primary and secondary metabolisms during the germination of Scutellaria baicalensis Georgi seeds under different light intensities. [Method] The activities of CHL, solub... [Objective] This study aimed to investigate the primary and secondary metabolisms during the germination of Scutellaria baicalensis Georgi seeds under different light intensities. [Method] The activities of CHL, soluble sugar, PAL, C4H and CHS were determined with ultraviolet spectrophotometry. The secondary metabolites were detected by High Performance Liquid Chromatography (HPLC). [Result] The results indicate that the germination of Scutellaria baicalensis Georgi seeds is not sensitive to light and the seedlings were very sensitive to light. The CHL, soluble sugar, PAL, C4H and CHS continuously increased with light intensity. The content of secondary metabolites also increased. [Conclusion] Light increased the formation of leaf photosynthetic pigment, thereby affecting the primary metabolites. The activities of PAL, C4H and CHS significantly increased with the development of light intensity. Finally the secondary metabolites of medicinal plants increased sharply. Therefore, the quality of Scutellaria baicalensis Georgi materials can be improved by increasing the light intensity moderately. 展开更多
关键词 Light intensity PAL C4H CHS Secondary metabolites
下载PDF
Line intensities of the asymptotic asymmetric-top radical HO_2 at high temperatures 被引量:3
4
作者 宋晓书 程新路 +2 位作者 杨向东 令狐荣锋 吕兵 《Chinese Physics B》 SCIE EI CAS CSCD 2008年第1期158-163,共6页
The total internal partition sums were calculated in the product approximation at temperatures up to 5000 K for the asymptotic asymmetric-top HO2 molecule. The calculations of the rotational partition function and the... The total internal partition sums were calculated in the product approximation at temperatures up to 5000 K for the asymptotic asymmetric-top HO2 molecule. The calculations of the rotational partition function and the vibrational partition function were carried out with the rigid-top model and in the harmonic oscillator approximation, respectively. Our values of the total internal partition sums are consistent with the data of HITRAN database with -0.14% at 296 K. Using the calculated partition functions, we have calculated the line intensities of υ2 band of HO2 at several high temperatures. The results showed that the calculated line intensities are in very good agreement with those of HITRAN database at temperatures up to 3000 K, which provides a strong support for the calculations of partition functions and line intensities at high temperatures. Then we have extended the calculation to higher temperatures. The simulated spectra of υ2 band of the asymptotic asymmetric-top HO2 molecule at 4000 and 5000 K are also obtained. 展开更多
关键词 asymptotic asymmetric-top molecule line intensities partition functions high temperature
下载PDF
Influence of Pressure and Discharge Voltage on Spectral Intensities in a Pulsed Nitrogen Discharge Supersonic Free-Jet
5
作者 吴其俊 祖莉莉 方维海 《Plasma Science and Technology》 SCIE EI CAS CSCD 2010年第3期320-324,共5页
The effects of the pressure and discharge voltage on the spectral intensities of the second positive and first negative systems were studied in a pulsed nitrogen discharge supersonic flee-jet. The results show that a ... The effects of the pressure and discharge voltage on the spectral intensities of the second positive and first negative systems were studied in a pulsed nitrogen discharge supersonic flee-jet. The results show that a stabilized discharge condition was reached when the vacuum chamber pressure increased to 100 Pa. Both N2(C^3∏u) and N+(B^2∑u^+) states were highly populated at a pressure of 100 Pa to 130 Pa. The active state N2(C^3∏u)could be selectively populated at a low pressure of 10 Pa and a discharge voltage of 4500 V. Different populating mechanisms under the experimental conditions for N2(C^3∏u) and N+(B^2∑u^+) states were proposed to account for the experimental results. 展开更多
关键词 spectral intensities pulsed discharge active state NITROGEN
下载PDF
Rotational analysis and line intensities of the HCO ~2A′-~2A′3_1~1 band at 296 K
6
作者 刘艳红 杜晓峰 程新路 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第9期339-343,共5页
This paper computes the rotational energy levels of the HCO B^2A'-X^2A'31^1 transition, especially, the higher values of the rotational quantum numbers NKa Kc and Ka, with the rotational constants which are obtained... This paper computes the rotational energy levels of the HCO B^2A'-X^2A'31^1 transition, especially, the higher values of the rotational quantum numbers NKa Kc and Ka, with the rotational constants which are obtained via B3LYP method with 6-311G basis set, and the results show that the calculated frequencies using the computed vibration-rotation energy levels are in reasonable agreement with the data from the experiment. Meanwhile, the line intensities of HCO are first reported, the results are of significance for the studying HCO. 展开更多
关键词 rotational energy levels line intensities vibration-rotation energy level FREQUENCY
下载PDF
Electric dipole moment function and line intensities for the ground state of carbon monxide
7
作者 陈华君 吴杰 +1 位作者 刘浩 程新路 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第8期261-270,共10页
An accurate electric dipole moment function(EDMF) is obtained for the carbon monoxide(CO) molecule(X1+Σ)by fitting the experimental rovibrational transitional moments. Additionally, an accurate ab initio EDMF is foun... An accurate electric dipole moment function(EDMF) is obtained for the carbon monoxide(CO) molecule(X1+Σ)by fitting the experimental rovibrational transitional moments. Additionally, an accurate ab initio EDMF is found using the highly accurate, multi-reference averaged coupled-pair functional(ACPF) approach with the basis set, aug-cc-p V6 Z, and a finite-field with ±0.005 a.u.(The unit a.u. is the abbreviation of atomic unit). This ab initio EDMF is very consistent with the fitted ones. The vibrational transition matrix moments and the Herman–Wallis factors, calculated with the Rydberg–Klein–Rees(RKR) potential and the fitted and ab initio EDMFs, are compared with experimental measurements. The consistency of these line intensities with the high-resolution transmission(HITRAN) molecular database demonstrates the improved accuracy of the fitted and ab initio EDMFs derived in this work. 展开更多
关键词 electric dipole moment vibrational transition matrix moments Herman–Wallis factors line intensities
下载PDF
A Study of the Impacts of the Spatial Differences in Climate Engineering Programs on the Intensities of Extreme High-Temperature Events in China Under A 1.5℃ Temperature Control Target
8
作者 KONG Feng 《Journal of Tropical Meteorology》 SCIE 2020年第2期161-175,共15页
Based on the daily maximum temperature data and average temperature data prediction for the period ranging from 2020 to 2099 under the scenario of BNU-ESM climate engineering(G4 test)and non-climate engineering(RCP4.5... Based on the daily maximum temperature data and average temperature data prediction for the period ranging from 2020 to 2099 under the scenario of BNU-ESM climate engineering(G4 test)and non-climate engineering(RCP4.5),the regional differences in the extreme high-temperature intensities in China during the implementation of climate engineering programs(2020 to 2069)and after the implementation of those programs(2070 to 2099)were analyzed using the Weibull Distribution Theory.The results are as follows.(1)The comparison of the two scenarios shows that climate engineering has not fundamentally changed the spatial variation of the intensity of extreme hightemperature events in different recurring periods in China.It was found that in both scenarios,the extreme hightemperature intensities were characterized by the spatial differentiations of low-temperature intensities on the QinghaiTibet Plateau,and high-temperature intensities in the eastern and northwestern region.(2)The comparison of the two scenarios shows that climate engineering in the two study periods could help mitigate the extreme high-temperature intensities with different recurrence periods in China,and the mitigation effects during the implementation period would be significantly higher than those after the implementation.(3)The comparison between the periods ranging from 2020 to 2069 and 2070 to 2099 under the proposed climate engineering scenarios suggests that there would be no strong rebounding of extreme high-temperatures following the implementation of climate engineering programs.Moreover,the mitigation effect of extreme high-temperature intensity during the implementation of climate engineering is significantly higher than that after the completion of climate engineering.(4)According to the comparison between the average temperature changes in China before and after the implementation of the climate project,the average temperature in China has been reduced by at least 1.25℃,which effectively alleviates global warming and is conducive to the realization of the 1.5℃temperature control target of the Paris Agreement. 展开更多
关键词 climate engineering extreme high-temperature intensities recurrence period spatial patterns climate changes
下载PDF
Determination of the Vibro-Rotational Constants, the Dipole Moment’s Function and the Intensities of the HTO’s ν1 (ν3 by Usual Convention) Band
9
作者 Modou Tine Diouma Kobor +1 位作者 Ibrahima Sakho Laurent Coudert 《Journal of Modern Physics》 2012年第12期1945-1957,共13页
In the first part of this paper, an analysis of the high-resolution spectrum of the HTO molecule ν1(ν3) band, from 3630 to3950 cm–1, was undertaken. The rotational transition of this band was assigned using combina... In the first part of this paper, an analysis of the high-resolution spectrum of the HTO molecule ν1(ν3) band, from 3630 to3950 cm–1, was undertaken. The rotational transition of this band was assigned using combination differences. Their wavenumbers were analyzed with a least squares fit program in order to obtain spectroscopic constants. A perturbed state has been evidenced. In the second part, with a view towards building a spectroscopic data base, a calculation of the dipolar momentum function was undertaken. 展开更多
关键词 Infrared SPECTRUM Energy Level RAYS intensities PERTURBATION
下载PDF
γ-ray Intensities, Branching Ratios and Relative Transition Probabilities in Rotational Bands of ^(170)Ta
10
《IMP & HIRFL Annual Report》 1998年第0期123-123,共1页
关键词 TRANSITION intensities TA TRANSITIONS
下载PDF
Insights into the differences in leaf functional traits of heterophyllous Syringa oblata under different light intensities 被引量:11
11
作者 Hongguang Xiao Congyan Wang +2 位作者 Jun Liu Lei Wang Daolin Du 《Journal of Forestry Research》 SCIE CAS CSCD 2015年第3期613-621,共9页
Many plants exhibit heterophylly; the spatially and temporally remarkable ontogenetic differences in leaf morphology may play an adaptative role in their success under diverse habitats. Thus, this study aimed to gain ... Many plants exhibit heterophylly; the spatially and temporally remarkable ontogenetic differences in leaf morphology may play an adaptative role in their success under diverse habitats. Thus, this study aimed to gain insights into differences in leaf functional traits of heterophyllous Syringa oblata Lindl., which has been widely used as an ornamental tree around the world under different light intensities in East China. No significant differences existed in specific leaf area (SLA) between lanceolate- and heart-shaped leaves. Differ- ences in the investment per unit of light capture surface area deployed between lanceolate- and heart-shaped leaves may benot obvious. This may be attributing to the fact that single leaf wet and dry weight of heart-shaped leaves were significantly higher than those of lanceolate leaves but leaf length and leaf thickness of heart-shaped leaves were significantly lower than those of lanceolate leaves. The SLA of shade trees was sig- nificantly higher than that of sun trees. The investment per unit of light capture surface of shade trees was lower than that of sun trees, making it possible to increase light capture and use efficiency in low-light environments. The phenotypic plas- ticity of most leaf functional traits of lanceoiate leaves was higher than those of heart-shaped leaves because the former is the juvenile and the latter is the adult leaf shape during the process of phylogenetic development of S. oblate. The higher range of phenotypic plasticity of leaf thickness and leaf moisture for sun trees may be beneficial to obtain a more efficient control of water loss and nutrient deprivation in high- light environments, and the lower range of phenotypic plas- ticity of single leaf wet and dry weight, and SLA for shade trees may gain an advantage to increase resource (especially light) capture and use efficiency in low-light environments. In brief, the successfully ecological strategy of plants is to find an optimal mode for the trade-off between various functional traits to obtain more living resources and achieve more fitness advantage as much as possible in the multivariate environment. 展开更多
关键词 Heterophylly Light intensity Specific leafareas Syringa oblata Lindl.
下载PDF
Clinical Study of Electro-acupuncture Treatment with Different Intensities for Functional Constipation Patients 被引量:9
12
作者 熊繁 王颖 +3 位作者 黎诗祺 田曼 郑翠红 黄光英 《Journal of Huazhong University of Science and Technology(Medical Sciences)》 SCIE CAS 2014年第5期775-781,共7页
Functional constipation (FC) is a common functional bowel disorder disease that affects life quality of a large number of people. This study aimed to explore the impact of different intensities of electro-acupunctu... Functional constipation (FC) is a common functional bowel disorder disease that affects life quality of a large number of people. This study aimed to explore the impact of different intensities of electro-acupuncture (EA) treatment for FC patients. Totally, 111 patients with FC meeting the Rome III criteria were randomly assigned to different intensities of EA groups (low and high intensity of EA groups) and medicine-controlled (MC) group. In EA groups, patients were treated with EA at quchi (Llll) and shangjuxu (ST37) bilaterally for 4 weeks, 5 times/week in the first 2 weeks, and 3 times/week in the last 2 weeks. In MC group, 5 mg mosapride citrate was administered orally 3 times/day for 4 weeks. Spontaneous bowel movement frequency each day was recorded using a consti- pation diary. Self-rating anxiety scale (SAS) and self-rating depression scale (SDS) were used to assess the patients' psychological state. Cortisol (CORT), substance P (SP), and vasoactive intestinal polypep- tide (VIP) were evaluated at baseline and at the end of 4 weeks after treatment. As compared with the baseline, there was statistically significant increase in stool frequency every week (P〈0.01), but there was no statistically significant difference among the three groups. As compared with the baseline, after 4 weeks of EA therapy, the scores of SDS and serum levels of CORT were decreased significantly in low intensity of EA group (P〈0.01), and the serum levels of SP and VIP were increased significantly (P〈0.05); the scores of SAS and SDS and serum levels of CORT were decreased significantly in high intensity of EA group (P〈0.05), and the serum levels of SP and VIP were increased significantly (P〈0.05); the serum levels of CORT and VIP were increased significantly in MC group (P〈0.05). As compared with MC group, after 4 weeks of treatment, the serum levels of SP were signifcicantly in- creased in low intensity of EA group (P〈0.01). Low and high intensities of EA could increase the stool frequency, improve the FC patient's anxiety and depression, reduce the serum levels of CORT, and in- crease the serum levels of SP and VIP effectively. It is concluded that both low and high intensities of EA are effective for FC patients, but there is no significant difference between the low and high intensi- ties of EA. 展开更多
关键词 ELECTRO-ACUPUNCTURE current intensity functional constipation quchi (Llll) shangjuxu(ST37)
下载PDF
Synchronization of Chaotic Intensities and Phases in an Array of N Lasers 被引量:5
13
作者 SUNJian ZHUShi-Qun 《Communications in Theoretical Physics》 SCIE CAS CSCD 2005年第2期233-239,共7页
A linear array of N mutually coupled single-mode lasers is investigated. It is shown that the intensities of N lasers are chaotically synchronized when the coupling between lasers is relatively strong. The chaotic syn... A linear array of N mutually coupled single-mode lasers is investigated. It is shown that the intensities of N lasers are chaotically synchronized when the coupling between lasers is relatively strong. The chaotic synchronization of intensities depends on the location of the lasers in the array. The chaotic synchronization appears between two outmost lasers, the second two outmost lasers, etc. There is no synchronization between nearest neighbors of the lasers. If the number of N is odd, the middle laser is never synchronized between any lasers. The chaotic synchronization of phases between nearest lasers in the array is examined by using the analytic signal and the Gaussian filter methods based on the peak of the power spectrum of the intensity. It can be seen that the message of chaotic intensity synchronization is conveyed through the phase synchronization. 展开更多
关键词 chaotic synchronization intensity phase linear array solid state lasers
下载PDF
Effects of light intensities and photoperiods on growth and proteolytic activity in purple non-sulfur marine bacterium, <i>Afifella marina</i>strain ME (KC205142) 被引量:6
14
作者 Sujjat Al-Azad Tan Kar Soon Julian Ransangan 《Advances in Bioscience and Biotechnology》 2013年第10期919-924,共6页
Afifella marina strain ME (KC205142), a purple non-sulfur bacterium was isolated from mangrove habitats of Sabah. The effects of light intensities and photoperiods on proteolytic activity in Afifella marina strain ME ... Afifella marina strain ME (KC205142), a purple non-sulfur bacterium was isolated from mangrove habitats of Sabah. The effects of light intensities and photoperiods on proteolytic activity in Afifella marina strain ME (KC205142) were investigated. Secretion of proteolytic enzymes in Afifella marina was preliminarily assessed by skim milk agarose media. Subsequently, light intensities, such as, dark, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500 and 5000 lux were used to evaluate the effects on proteolytic activity in Afifella marina strain ME under anaerobic condition. After that, the effect of photoperiods on proteolytic activity was monitored under anaerobic light condition (3000 lux) at 0 h (0L/24D), 6 h (6L/18D), 12 h (12L/12D), 18 h (18L/6D) and 24 h (24L/0D) of photoperiod. The highest proteolytic activity of 74.67 U was recorded at 3000 lux illumination light intensity. The proteolytic activity in bacterium Afifella marina strain ME was positively associated with the dry cell weight. The proteolytic activity of 72.67 U in bacterium Afifella marina strain ME at 18 h (18L/6D) photoperiod is not significantly different (p > 0.05) from proteolytic activity of 74.67 U recorded at continuous light (24L/0D) condition. Light intensity of 3000 lux, culture period of 48 h and a photoperiod of 18 h (18L/ 6D) were the optimum parameters for proteolytic activity in bacterium Afifella marina strain ME. 展开更多
关键词 Afifella MARINA LIGHT Intensity Photoperiod Proteolytic Activity PURPLE NON-SULFUR Bacteria
下载PDF
Assessing the influence of harvesting intensities on structural diversity of forests in south-west Germany 被引量:2
15
作者 Felix Storch Gerald Kadler Jürgen Bauhus 《Forest Ecosystems》 SCIE CSCD 2019年第3期249-260,共12页
Background: To increase ecosystem resilience and biodiversity, the maintenance and improvement of structural and compositional diversity of forests has become an important goal in forest management for many forest own... Background: To increase ecosystem resilience and biodiversity, the maintenance and improvement of structural and compositional diversity of forests has become an important goal in forest management for many forest owners and jurisdictions. At the same time, future harvesting intensity (HI) may increase to meet the demand for woody biomass by an increasing bioeconomy sector. Yet, the influence of HI on forest structural diversity is largely unknown. Here, we address this issue by analyzing the relationship between HI and structural diversity based on large-scale national forest inventory (NFI) data, where the latter is quantified using a previously developed Forest Structure Index and HI is expressed as wood volume removal during the period 2002-2012 for the same inventory plots. Results: Our results show a surprisingly small impact of harvesting intensity on changes in structural diversity for most of the analysed types of forests. Only intense harvesting (> 80%-90% of initial growing stock) led to a significant reduction in structural diversity. At low to moderate HI most aspects of structural diversity were positively influenced. Only the quadratic mean DBH and the volume of large trees (≥ 40 cm DBH) were substantially negatively influenced at HI > 60% and 70% of initial growing stock, respectively. Conclusions: In several forest types, HI could be increased without a reduction in overall structural diversity. Hence, structural diversity in these selectively managed forests appears to be a very resistant forest property in relation to HI. Other indicators at stand and landscape scale may be needed to adjust levels of HI that are suited to maintain forest biodiversity. 展开更多
关键词 Large-scale INVENTORY STRUCTURAL DIVERSITY index HARVESTING intensity Changes in STRUCTURAL DIVERSITY
下载PDF
Changes in the Photosynthetic Pigment Contents and Transcription Levels of Phycoerythrin-Related Genes in Three Gracilariopsis lemaneiformis Strains Under Different Light Intensities 被引量:2
16
作者 CAO Xuexue WANG Haitao +5 位作者 ZANG Xiaonan LIU Zhu XU Di JIN Yuming ZHANG Feng WANG Zhendong 《Journal of Ocean University of China》 SCIE CAS CSCD 2021年第3期661-668,共8页
Three Gracilariopsis lemaneiformis strains,including wild type and high-temperature-resistant cultivars 981 and 2007,were studied with the changes in their photosynthetic pigment contents and related gene transcriptio... Three Gracilariopsis lemaneiformis strains,including wild type and high-temperature-resistant cultivars 981 and 2007,were studied with the changes in their photosynthetic pigment contents and related gene transcription levels under different light intensities(10,60,100,and 200μmolm^(−2)s^(−1)).The three G.lemaneiformis strains had the following photosynthetic pigments with high-to-low contents:phycoerythrin(PE),phycocyanin(PC),allophycocyanin(APC),and chlorophyll a(Chl a).Among the three strains,cultivar 981 had the highest PE content,followed by cultivar 2007.The PC and APC contents were similar among the three strains,but they were higher in cultivars 981 and 2007 than in the wild type.The Chl a contents in the three G.lemaneiformis strains were equal.A low light intensity(10μmolm^(−2)s^(−1))promoted photosynthetic pigment accumulation in G.lemaneiformis and improved the relative PE gene transcription(peA and peB)in a short period(≤6 d).A high light intensity decreased the PE content.PebA and PebB,which catalyzed phycoerythrobilin synthesis,showed no compensatory upregulation at a low light intensity among the strains except for the wild type.At a high light intensity,transcription levels of pebA and pebB in the three strains were upregulated.This study provided an experimental basis for elucidating the photosynthesis of G.lemaneiformis.As key genes of algal growth,photo-synthesis-related genes served as useful gene markers for screening elite varieties with good traits in breeding.Cultivar 2007 was superior to cultivar 981 in terms of maintaining high pigment levels in a wide range of light intensities,which is the most suitable for aquaculture. 展开更多
关键词 Gracilariopsis lemaneiformis light intensity photosynthetic pigment PE gene transcription
下载PDF
Nonlinearity Modulating Intensities and Spatial Structures of Central Pacific and Eastern Pacific El Nio Events 被引量:2
17
作者 Wansuo DUAN Chaoming HUANG Hui XU 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2017年第6期737-756,共20页
This paper compares data from linearized and nonlinear Zebiak-Cane model, as constrained by observed sea surface temperature anomaly (SSTA), in simulating central Pacific (CP) and eastern Pacific (EP) E1 Nino. T... This paper compares data from linearized and nonlinear Zebiak-Cane model, as constrained by observed sea surface temperature anomaly (SSTA), in simulating central Pacific (CP) and eastern Pacific (EP) E1 Nino. The difference between the temperature advections (determined by subtracting those of the linearized model from those of the nonlinear model), referred to here as the nonlinearly induced temperature advection change (NTA), is analyzed. The results demonstrate that the NTA records warming in the central equatorial Pacific during CP E1 Nino and makes fewer contributions to the structural distinctions of the CP E1 Nino, whereas it records warming in the eastern equatorial Pacific during EP E1 Nino, and thus significantly promotes EP E1 Nino during E1 Nino-type selection. The NTA for CP and EP E1 Nino varies in its amplitude, and is smaller in CP E1 Nino than it is in EP E1 Nino. These results demonstrate that CP E1 Nino are weakly modulated by small intensities of NTA, and may be controlled by weak nonlinearity; whereas, EP E1 Nino are significantly enhanced by large amplitudes of NTA, and are therefore likely to be modulated by relatively strong nonlinearity. These data could explain why CP E1 Nino are weaker than EP E1 Nino. Because the NTA for CP and EP E1 Nino differs in spatial structures and intensities, as well as their roles within different E1 Nino modes, the diversity of E1 Nino may be closely related to changes in the nonlinear characteristics of the tropical Pacific. 展开更多
关键词 E1 Nifio diversity NONLINEARITY INTENSITY spatial structures nonlinear temperature advection
下载PDF
Near ground wind characteristics during typhoon Meari:Turbulence intensities, gust factors, and peak factors 被引量:1
18
作者 WANG Xu HUANG Peng +1 位作者 YU Xian-feng HUANG Chao 《Journal of Central South University》 SCIE EI CAS CSCD 2017年第10期2421-2430,共10页
Wind data were collected during the 2011 typhoon Meari at heights of 10, 20, 30, and 40 m above the ground using a 40 m high anemometer tower in the coastal area near Shanghai Pudong International Airport. Wind speeds... Wind data were collected during the 2011 typhoon Meari at heights of 10, 20, 30, and 40 m above the ground using a 40 m high anemometer tower in the coastal area near Shanghai Pudong International Airport. Wind speeds and directions, turbulence intensities, gust factors, and peaks were analyzed using the time records of wind speed. The results show that turbulence intensity components in longitudinal, lateral, and vertical directions decrease with mean wind speed, regardless of elevations, and the turbulence intensities are in a linear relationship with mean wind speeds. The ratios of three turbulence intensity components(i.e. Iu, Iv, Iw) at heights of 10, 20 and 40 m were calculated and equal to be 1:0.88:0.50, 1:0.84:0.57, and 1:0.9:0.49, respectively. In addition, the gust factors in three directions exhibit a reduction with increasing mean wind speed. The peak factors at different heights show a similar trend and slightly decrease with mean wind speed; average peak factors for all 10-min data from Typhoon Meari are 2.43, 2.48, and 2.47, respectively. 展开更多
关键词 TYPHOON Meari wind characteristics TURBULENCE intensity GUST FACTOR peak FACTOR
下载PDF
Effects of Different Grazing Intensities on Vegetation Characteristics of Cultivated Pastures in Southern China 被引量:2
19
作者 WAN Li-qiang,LI Xiang-lin ,HE Feng,CHEN Wei-wei,WAN Jiang-chun,ZHAO Yun,WU Wei-da Institute of Animal Sciences,Chinese Academy of Agricultural Sciences,Beijing 100193,China 《Animal Husbandry and Feed Science》 CAS 2012年第2期72-75,96,共5页
[Objective]The paper was to study the effect of different grazing intensities on vegetation characteristics of artificial pasture by plot rota- tion grazing experiment. [Method]Grazing intensity was divided into 2 tre... [Objective]The paper was to study the effect of different grazing intensities on vegetation characteristics of artificial pasture by plot rota- tion grazing experiment. [Method]Grazing intensity was divided into 2 treatments of heavy grazing and light grazing,and each treatment contained 6 plots,with randomized complete block design. A blank control was set near test plot. Ninety disease-free and healthy 2-year-old Yunling Black Goats with consistent body condition were selected and divided into 2 groups: heavy grazing ( 55) and light grazing ( 35) . The goats were conduc- ted rotation grazing in 6 plots,and the average stocking rates were 12. 6 and 8 goat /hm 2 . The plant height,coverage,underground biomass and pasture plant nutrition of 2 treatments were measured,respectively. [Result]The cocksfoot height had significant difference with control under graz- ing conditions ( P 〈0. 05) ,while the heights of ryegrass and white clover in control plot had no significant difference with that in grazing plot ( P 〉 0. 05) . Grazing intensity had different effects on coverage of different plants; grazing utilization reduced the coverage of cocksfoot and ryegrass, which had little impact on coverage of white clover; viewed from the whole plant communities,the coverage in control plot was greater than that in grazing plot. The underground biomass in 0 -20 cm soil depth in grazing plot accounted for about 90%; with the increase of grazing intensity,un- derground biomass was decreased. The crude protein ( CP) and crude fat ( EE) content of forage decreased,while acid detergent fiber ( ADF) and neutral detergent fiber ( NDF) increased. [Conclusion]The research provided scientific basis for determination of suitable grazing system and sus- tainable utilization of pasture resources. 展开更多
关键词 Grazing intensity Artificial pasture Vegetation characteristics
下载PDF
Three-dimensional ab initio dipole moment surfaces and stretching vibrational band intensities of the XH3 molecules 被引量:1
20
作者 刘安雯 胡水明 +1 位作者 丁昀 朱清时 《Chinese Physics B》 SCIE EI CAS CSCD 2005年第10期1946-1953,共8页
Stretching vibrational band intensities of XH3 (X=N, Sb) molecules are investigated employing three-dimensional dipole moment surfaces combined with the local mode Hamiltonian model. The dipole moment surfaces of NH... Stretching vibrational band intensities of XH3 (X=N, Sb) molecules are investigated employing three-dimensional dipole moment surfaces combined with the local mode Hamiltonian model. The dipole moment surfaces of NH3 and SbH3 are calculated with the density functional theory and at the correlated MP2 level, respectively. The calculated band intensities are in good agreement with the available experimental data. The contribution to the band intensities from the different terms in the polynomial expansion of the dipole moments of four group V hydrides (NH3, PH3, AsH3 and SbH3) are discussed. It is concluded that the breakdown of the bond dipole approximation must be considered. The intensity “borrowing” effect due to the wave function mixing among the stretching vibrational states is found to be less significant for the molecules that reach the local mode limit. 展开更多
关键词 OVERTONE dipole moment infrared band intensity local mode
下载PDF
上一页 1 2 166 下一页 到第
使用帮助 返回顶部