oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 25 )

2018 ( 182 )

2017 ( 173 )

2016 ( 185 )

Custom range...

Search Results: 1 - 10 of 14263 matches for " Shen Yunfen "
All listed articles are free for downloading (OA Articles)
Page 1 /14263
Display every page Item
Intraspecific phylogeography of Carchesium polypinum (Peritrichia, Ciliophora) from China, inferred from 18S-ITS1-5.8S ribosomal DNA
Wei Miao,Yuhe Yu,Yunfen Shen,Xiyuan Zhang
Science China Life Sciences , 2004, DOI: 10.1360/02yc0157
Abstract: Based on the variation of site 34, 46, 241, 305 and 322 in the 18S-ITS1 rDNA sequence, 19 Carchesium polypinum populations collected from eight provinces of China were separated into northern and southern population along the delineation between the Yangtze River and the Pearl River. This geographic distribution pattern of Carchesium polypinum maybe results from two factors: the vicariance resulting from the formation of the delineation between the Pearl River and the Yangtze River accompanied with the uplift of Qinghai-Xizang Plateau, and the different dispersal paths of C. polypinum affected by the climate.
Phylogenetic relationships among six species of Epistylis inferred from 18S-ITS1 sequences
Miao Wei,Yu Yuhe,Shen Yunfen,Zhang Xiyuan
Science China Life Sciences , 2002, DOI: 10.1360/02yc9031
Abstract: Phylogenetic relationships among six species of Epistylis (i. e. E. plicatilis, E. urceolata, E. chrysemydis, E. hentscheli, E. wenrichi, and E. galea) were investigated using sequences of the first internal transcribed spacer region (ITS-1) of ribosomal DNA (rDNA). Amplified rDNA fragment sequences consisted of 215 or 217 bases of the flanking 18S and 5.8S regions, and the entire ITS-1 region (from 145 to 155 bases). There were more than 33 variable bases between E. galea and the other five species in both the 18S region and the ITS-1 region. The affiliation of them was assessed using Neighbor-joining (NJ), maximum parsimony (MP) and maximum likelihood (ML) analyses. In all the NJ, MP and ML analyses E. galea, whose macronucleic position and shape are distinctly different from those of the other five species, was probably diverged from the ancestor of Epistylis earlier than the other five species. The topology in which E. plicatilis and E. hentscheli formed a strongly supported sister clade to E. urceolata, E. chrysemydis, and E. wenrichi was consistent with variations in the thickness of the peristomial lip. We concluded that the macronucleus and peristomial lip might be the important phylogenetic characteristics within the genus Epistylis.
Discrimination of water quality based on PFU microbial communities and changing pattern of microbial parameters
PFU微型生物群落水质鉴别及群落参数变化模式的研究

CHEN Jian,SHEN Yunfen,
陈建
,沈韫芬

环境科学学报 , 2000,
Abstract: By means of discriminant analysis,integrating data of five biotic parameters ( HI,D,Seq,G and T 90% ) of microbial communities in water system of 26 stations from two regions,the canonical discriminant functions and classification functions were established and analysis of correlation of paramenters of microbial communities with chemical combined pollution index ( P ) and correlation among five biotic paramenters have carried out.Groups to which stations belong respectively can be differentiated efficiently by canonical functions obtained.Classification functions obtained can be used directly to classify stations.Group predicted for all stations,except of one station,was same as group marked according to P .Further analysis of correlation of biotic parameters with P indicated that,along water unpolluted to seriously polluted,there was an interval within which characteristics of correlation of five biotic parameters with P changed sharply.In that interval,correlations of D and Seq with P turned from positive to negative, T 90% from negative correlation to positive correlation, HI from non\|significant positive correlation to significant positive correlation, G from significant positive correlation to nonsignificant correlation.The turning interval to refer this interval which,according to the present study,may exist in the interval of water polluted.
Restoration processes of pollution zones in Hanjiang River
Shen Yunfen,Tan Yuyun,Feng Weisong,Gu Manru,
Shen Yunfen
,Tan Yuyun,Feng Weisong,Gu Manru,He Chengying,Li Aiguo

环境科学学报(英文版) , 1996,
Abstract: Two pollution zones in middle and lower reaches of Hanjiang River were selected for studying restoration processes. In each zones 6 stations were set up in upper stream of sewage outfall, 50m, 100 or 150m, 250 or 525m and 1250 or 3500m apart from the outfall. Chemical monitoring and microbial community biomonitoring were carried out simultaneously. Either the chemical monitoring or the biological monitoring proved the self-purification process of water body along with the increased distance from the sewage outfall. 4 biological parameters (species number of protozoa, percentage of phytomastigophora, diversity index and heterotrophy index) and parameter Seq of the colonization process all have statistically significant correlations with chemical comprehensive pollution indexes Pa and Pb.
ECOLOGICOL STUDIES ON THE FOREST SOIL PROTOZOA OF MOUNT LUOJIASHAN AND EXPLORATION OF QUANTITATIVE METHODS FOR SOIL PROTOZOA
珞珈山森林土壤原生动物生态学研究及土壤原生动物定量方法探讨

Ning Yingzhi,Shen Yunfen,
宁应之
,沈韫芬

动物学研究 , 1996,
Abstract: The forest soil protozoa of Mount Luojia was studied quantitatively with both directand culture counting methods from January to December in 1993. It was dicovered that the summit of the annual abundance dynamics of protozoa was in spring (March, April & May),the valley in winter (January & Febrary), and the abundance fluntuated gently in summer and fall. The results of regression analyses showed that there were obvious positive correlations between the annual dynamics of protozoan abundance and the variations of water amount and PH value of the soil, and there was no obvious correlation between the dynamics and the variations of the soil temperature. The dominant species were Bodo edax, Trinemalinears, T. enchelys, B. globosus, Centropyxis elongata, Cryptomonas ovata, Cyclopyxis eurostoma and Cercomonas longicauda. The common species were B. edax, B. globosus,Pleuromonas Pculans, T. linears, T. enchelys, Centropyxis elongata, Colpoda inflata, C. steinii,Leptopharynx costatus, Frontonia depressa, Cercomonas longycauda, C. cucullus and Monas minimum. The variation trend of protozoan abundance showed by the two counting methodswas consistent, but the results of the culture method were 102 to 103 times as much as the ones of the direct counting method. This demonstrated that most of protozoan individuals existed in cyst forms and only small numbers in active forms in soil, and on the other hand, the culture counting method overestimated the standing crop of soil protozoa. Therefore, we believed that direct counting method gives more reliable estimations of the abundance of soilprotozoa and it is better to adopt direct counting method if the objective conditions permit.
The Study on Improving the Anti Cutting Fracture Property of Hard Alloy Tool by Ion Beam Enhanced Deposition Method
离子束增强沉积氮化钛膜改善硬质合金刀具抗切削损伤性能的研究

Zhang Zongcheng,Bei Yunfen,Du Peixian,Shen Jian,
章宗城
,柳襄怀

摩擦学学报 , 1996,
Abstract: The anti cutting fracture properties of hard alloy tool coated TiN film by ion beam enhanced deposition(IBED) and ion plating(IP) methods were investigated compared with that of tool uncoated TiN film.The results showed that in the given conditions,the cutting distance of tool coated by IBED is longer than those of tools uncoated and by IP,and the fracture degree of tool coated by IBED is the smallest on its face and back.As a result of each parameter can be regulated individually during IBED process and the quality of film can be controlled,the harden film can be formed on the surface of tool.Wear and brittle damage is the main reasons of cutting fracture of tool.This is related to the adhesion between tool material and cutted metal.
Phylogenetic relationships among six species of Epistylis
Phylogenetic relationships among six species of Epistylis inferred from 185-ITS1 sequences

MIAO Wei,YU Yuhe,SHEN Yunfen,ZHANG Xiyuan,
缪炜
,余育和,沈韫芬,张锡元

中国科学C辑(英文版) , 2002,
Abstract: Phylogenetic relationships among six species of Epistylis (i. e. E. plicatilis, E urceolata, E chrysemydis, E. hentscheli, E. wenrichi, and E. galea) were investigated using sequences of the first internal transcribed spacer region (ITS-1) of ribosomal DNA (rDNA). Amplified rDNA fragment sequences consisted of 215 or 217 bases of the flanking 18S and 5.8S regions, and the entire ITS-1 region (from 145 to 155 bases). There were more than 33 variable bases between E. galea and the other five species in both the 18S region and the ITS-1 region. The affiliation of them was assessed using Neighbor-joining (NJ), maximum parsimony (MP) and maximum likelihood (ML) analyses. In all the NJ, MP and ML analyses E. galea, whose macronucleic position and shape are distinctly different from those of the other five species, was probably diverged from the ancestor of Epistylis earlier than the other five species. The topology in which E. plicatilis and E. hentscheli formed a strongly supported sister clade to E. urceolata, E. chrysemydis, and E. wenrichi was consistent with variations in the thickness of the peristomial lip. We concluded that the macronucleus and peristomial lip might be the important phylogenetic characteristics within the genus Epistylis.
Intraspecific phylogeography of Carchesium polypinum (Peritrichia, Ciliophora) from China, inferred from 18S-ITS1-5.8S ribosomal DNA
MIAO Wei,YU Yuhe SHEN Yunfen ZHANG Xiyuan,
MIAO Wei
,YU Yuhe,SHEN Yunfen & ZHANG Xiyuan Donghu Experimental Station of Lake Ecosystems,Chinese Academy of Sciences,Wuhan,China,Institute of Hydrobiology,Chinese Academy of Sciences,Wuhan,China,College of Life Sciences,Wuhan University,Wuhan,China

中国科学C辑(英文版) , 2004,
Abstract: Based on the variation of site 34, 46, 241, 305 and 322 in the 18S-ITS1 rDNA sequence, 19 Carchesium polypinum populations collected from eight provinces of China were separated into northern and southern population along the delineation between the Yangtze River and the Pearl River. This geographic distribution pattern of Carchesium polypinum maybe results from two factors: the vicariance resulting from the formation of the delineation between the Pearl River and the Yangtze River accompanied with the uplift of Qinghai-Xizang Plateau, and the different dispersal paths of C. polypinum affected by the climate.
The Role of Structure in the Protein Dynamical Transition
Yunfen He,Andrea G. Markelz
Physics , 2008,
Abstract: The protein dynamical transition is investigated as a function of protein structure using terahertz time domain spectroscopy (THz-TDS). Measurements performed for native state and denatured hen egg white lysozyme (HEWL) show that protein structure is not necessary for the dynamical transition. We find the temperature dependence follows activated behavior and there is no evidence of a fragile to strong transition. Measurements of short chain poly alanine show a dynamical transition down to penta-alanine, however no transition is observed for di-alanine or tri-alanine. These measurements demonstrate that the temperature dependence arises strictly from the interaction of the side chains with the solvent. The lack of a transition for shorter chain polypeptides may indicate the temperature dependence arises from a net ordering of the adjacent water which scales with the length of the polypeptide chain.
A STUDY ON THE CARBON CYCLE IN THE AGRO-ECOLOGICAL SYSTEM OF CHINA
农业生态系统碳循环研究

Liu Yunfen,
刘允芬

自然资源学报 , 1995,
Abstract: In order to have a clear idea about the carbon cycle in the agro-ecological system of China,the uptake, emission,fixation and transfer of CO2 by the system in the years 1990 and 2000 are calculated and analysed,and a schematic map of carbon cycle in the agro-ecological system of China is drawn. The results indicate that the percentages occupied by the emission amount,fixation amount and transfer amount are 89. 7% 91.0% and 9.12% of the uptake amount respectively in the year 1990,and they are 7.83%, 1.18% and 1.16% respectively in the year 2000. It can be seen clearly that the CO2 uptake amount of the agro-ecological system of China is greater than the CO2 emission amount,and the system is a"sink"but not a"source"in respect to the atmospheric CO2 concentration in both the current periat and the peried after climatic change.
Page 1 /14263
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.