13 results on '"Zhong-Chao, Li"'
Search Results
2. Corrosion resistance of Mg(OH)2/Mg–Al-layered double hydroxide coatings on magnesium alloy AZ31: influence of hydrolysis degree of silane
- Author
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Shaokang Guan, Zhong-Chao Li, Qing-Song Yao, Rong-Chang Zeng, Fen Zhang, Xiaobo Chen, Zai-Meng Qiu, and Dongchu Chen
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Materials science ,Methyltrimethoxysilane ,Magnesium ,Metals and Alloys ,chemistry.chemical_element ,engineering.material ,Condensed Matter Physics ,Silane ,Corrosion ,chemistry.chemical_compound ,Coating ,chemistry ,Materials Chemistry ,engineering ,Hydroxide ,Physical and Theoretical Chemistry ,Fourier transform infrared spectroscopy ,Magnesium alloy ,Nuclear chemistry - Abstract
Mg(OH)2/Mg–Al-layered double hydroxide (LDH) coatings were modified with methyltrimethoxysilane (MTMS) on magnesium alloys. Effect of hydrolysis degree of silane solution on coating formation was investigated. Chemical compositions and surface morphologies of the coatings were examined using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and field-emission scanning electronic microscopy (FESEM). Results indicated that the composite coatings consisted of polymethyltrimethoxysilane (PMTMS), LDH and Mg(OH)2. Electrochemical and hydrogen evolution measurements revealed that the composite coatings possessed good corrosion resistance, especially the ones prepared in a high hydrolysis degree of silane. The optimum corrosion resistance of the composite coating was LDH/PMTMS-3 coating, which had the lowest value of corrosion current density (5.537 × 10−9 A·cm−2) and a dense surface. Plausible mechanism for coating formation and corrosion process of MTMS-modified Mg(OH)2/Mg–Al-LDH coatings were discussed.
- Published
- 2019
3. Simplified Analytical Method for Predicting the Lateral Ground Displacements due to Shield Tunnelling
- Author
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Lianwei Sun, Zhong-chao Li, and Rong-zhu Liang
- Subjects
Earth pressure balance ,Article Subject ,0211 other engineering and technologies ,02 engineering and technology ,010502 geochemistry & geophysics ,Engineering (General). Civil engineering (General) ,01 natural sciences ,Lateral displacement ,Current (stream) ,Shield tunnelling ,Shield ,Head (vessel) ,Geotechnical engineering ,TA1-2040 ,Displacement (fluid) ,Quantum tunnelling ,Geology ,021101 geological & geomatics engineering ,0105 earth and related environmental sciences ,Civil and Structural Engineering - Abstract
Earth pressure balance or slurry shield tunnelling will squeeze the subsoils and lead to lateral outward ground displacement. However, current methods to estimate the shield tunnelling-induced ground displacements generally use the methods based on the face unsupported tunnelling (e.g., New Austrian tunnelling and open shield excavation), which cannot predict the lateral ground movement due to shield tunnelling. In this paper, a novel simplified analytical method is proposed to predict the ground lateral displacement during the shield advancing process. The key shield tunnelling operation factors, including the additional pressure of cutter head, the friction forces around shield body, the back-fill grouting pressure, and the soil volume loss are all considered. The lateral ground displacements induced by the four former factors are calculated by using Mindlin’s solutions. The soil volume loss-induced lateral ground displacement is calculated by employing the expression introduced by Pinto and Whittle. Combining with the displacement obtained from all the factors, the analytical method for lateral ground displacement induced by shield tunnelling is obtained. The applicability of the proposed analytical approach is verified with three well-documented case histories involving slurry shield and EPB shield machines.
- Published
- 2021
4. Phylogeography and conservation genetics of the rare and relict Bretschneidera sinensis (Akaniaceae)
- Author
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Zhong-Chao Li, Mei-Na Wang, Elizabeth A. Zimmer, Lei Duan, Zheng-Feng Wang, Hong-Feng Chen, and Qi Qiao
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0106 biological sciences ,0301 basic medicine ,Conservation genetics ,Heredity ,Range (biology) ,Population genetics ,01 natural sciences ,Polymerase Chain Reaction ,Biochemistry ,Geographical Locations ,Flowering Plants ,Data Management ,education.field_of_study ,Multidisciplinary ,Geography ,Ecology ,DNA, Chloroplast ,Eukaryota ,Phylogenetic Analysis ,Plants ,Nucleic acids ,Phylogenetics ,Phylogeography ,Genetic Mapping ,Biogeography ,Medicine ,Research Article ,Chloroplast DNA ,China ,Conservation of Natural Resources ,Computer and Information Sciences ,Asia ,Ecological Metrics ,Forms of DNA ,Science ,Population ,Zoology ,Biology ,Genes, Plant ,010603 evolutionary biology ,03 medical and health sciences ,Genetic variation ,Genetics ,Evolutionary Systematics ,Bretschneidera ,education ,Taxonomy ,Evolutionary Biology ,Population Biology ,Ecology and Environmental Sciences ,Organisms ,Genetic Variation ,Biology and Life Sciences ,Species Diversity ,DNA ,Akaniaceae ,biology.organism_classification ,030104 developmental biology ,Haplotypes ,Brassicaceae ,People and Places ,Earth Sciences ,Population Genetics - Abstract
Bretschneidera sinensis, a class-I protected wild plant in China, is a relic of the ancient Tertiary tropical flora endemic to Asia. However, little is known about its genetics and phylogeography. To elucidate the current phylogeographic patterns and infer the historical population dynamics of B. sinensis, and to make recommendations for its conservation, three non-coding regions of chloroplast DNA (trnQ-rps16, rps8-rps11, and trnT-trnL) were amplified and sequenced across 256 individuals from 23 populations of B. sinensis, spanning 10 provinces of China. We recognized 13 haplotypes, demonstrating relatively high total haplotype diversity (hT = 0.739). Almost all of the variation existed among populations (98.09%, P < 0.001), but that within populations was low (1.91%, P < 0.001). Strong genetic differentiation was detected among populations (GST = 0.855, P < 0.001) with limited estimations of seed flow (Nm = 0.09), indicating that populations were strongly isolated from one another. According to SAMOVA analysis, populations of B. sinensis in China could be divided into five geographic groups: (1) eastern Yunnan to western Guangxi; (2) Guizhou-Hunan-Hubei; (3) central Guangdong; (4) northwestern Guangdong; and (5) the Luoxiao-Nanling-Wuyi -Yangming Mountain. Network analysis showed that the most ancestral haplotypes were located in the first group, i.e., the eastern Yungui Plateau and in eastern Yunnan, which is regarded as a putative glacial refugia for B. sinensis in China. B. sinensis may have expanded its range eastward from these refugia and experienced bottleneck or founder effects in southeastern China. Populations in Liping (Guizhou Province), Longsheng (Guangxi Province), Huizhou (Guangdong Province), Chongyi (Jiangxi Province), Dong-an (Hunan Province), Pingbian (Yunnan Province) and Xinning (Hunan Province) are proposed as the priority protection units.
- Published
- 2017
5. Local genetic structure in the critically endangered, cave-associated perennial herbPrimulina tabacum(Gesneriaceae)
- Author
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Zhang-Ming Wang, Zhong-Chao Li, Wanhui Ye, Kai-Ming Liang, Qianmei Zhang, Hai Ren, and Zheng-Feng Wang
- Subjects
Conservation genetics ,Genetic divergence ,Critically endangered ,Genetic diversity ,education.field_of_study ,Ecology ,Genetic marker ,Genetic variation ,Genetic structure ,Population ,Biology ,education ,Ecology, Evolution, Behavior and Systematics - Abstract
The local spatial genetic structures of cave-associated plants are seldom studied. Given that these plants are mainly confined to small areas in and around the entrances of caves, we hypothesized that they might lack genetic structures at local scales. To test this hypothesis, we sampled two large populations (named D and T) of a critically endangered perennial herb, Primulina tabacum, which is endemic to karst caves in southern China. We analysed nine microsatellite loci and sequenced four chloroplast DNA (cpDNA) intergenic spacer regions to study the genetic diversity and structure within and between both populations. Both populations have distinct genetic characteristics. Samples from two subpopulations in population D showed considerable genetic divergence. This is not consistent with the hypothesis that P. tabacum has a weak genetic structure at a local scale. However, 94% of the individuals in population T shared the same multilocus genotype, which indicates little genetic structure within this population. The contributions of seed flow, pollen flow and (sub)population history to the genetic diversity and structure in each and both populations are discussed. Our study is the first to investigate local genetic diversity and structure in a cave-associated plant, and provides valuable information for the sustainable conservation of such species. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109, 747–756.
- Published
- 2013
6. Genetic variation of Ardisia crenata in south China revealed by nuclear microsatellite
- Author
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Hong-Lin Cao, Hong-Ping Mu, Zhong-Chao Li, Zhang-Ming Wang, Hao Shen, Zheng-Feng Wang, Wan-Hui Ye, and Lan Hong
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Genetic diversity ,Fixation (population genetics) ,biology ,Genetic variation ,Botany ,Ardisia crenata ,Ardisia ,Plant Science ,biology.organism_classification ,Inbreeding ,Ecology, Evolution, Behavior and Systematics ,Gene flow ,Fixation index - Abstract
Ardisia crenata Sims, one of the most widely distributed Ardisia in the world, is an important ornamental and medicinal plant species. Using seven polymorphic nuclear microsatellite loci, we studied the genetic variation of 20 natural populations of A. crenata across its distribution center in south China. Significant deviation from the Hardy–Weinberg equilibrium in all populations and at all loci were detected, and the fixation index was high (FIS= 0.725), indicating that inbreeding may be dominant in the mixed mating system of this self-compatible species. The average genetic diversity within populations was relatively low (HS= 0.321). There was significant genetic differentiation among populations (FST= 0.583), which may have resulted from a high level of inbreeding and a low level of gene flow. Ardisia crenata in south China can be roughly divided into an eastern group and a western group, consistent with the floristic division of the Sino-Himalayan forest subkingdom and the Sino-Japanese forest subkingdom. There may be separated glacial refugia in each region.
- Published
- 2010
7. The Effect of Acid Stress Treatment on Viability and Membrane Fatty Acid Composition of Oenococcus oeni SD-2a
- Author
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Hua Li, Zhong-chao Li, Wen-ying Zhao, Hua Wang, and Ai-lian Wang
- Subjects
biology ,Strain (chemistry) ,Membrane lipids ,Gram-positive bacteria ,Plant Science ,biology.organism_classification ,Lactic acid ,chemistry.chemical_compound ,Membrane ,Biochemistry ,chemistry ,Saturated fatty acid ,Malolactic fermentation ,Agronomy and Crop Science ,Oenococcus oeni - Abstract
To obtain ready-to-use wine malolactic starter cultures with high viability, the effects of acid stress treatments on the growth, inoculation viability, freeze-drying viability, and membrane fatty acid composition of the native Oenococcus oeni SD-2a strain were studied. The results showed that pH 3.5 and 3.2 adaptive treatments did not strongly decrease cell biomass but increased distinctly inoculation viability and freeze-drying viability. Concerning the membrane fatty acid composition, it was observed that acid stress conditions increased significantly the relative concentration of lactobacillic acid (C19cyc11) and the unsaturated:saturated fatty acid ratio in cell membrane lipids. We assumed that acid-induced cross protective responses could be used in preparing ready-to-use O. oeni SD-2a malolactic starter cultures, and the accumulation of lactobacillic acid in the membrane of O. oeni SD-2a cells appears as an acid stress response mechanism, which might be related with the enhanced viability.
- Published
- 2009
8. Genetic Diversity of the Relict Plant Taiwania cryptomerioides Hayata (Cupressaceae) in Mainland China
- Author
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Xiao-Lan Wang, Xue-Jun Ge, and Zhong-Chao Li
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Mainland China ,Genetic diversity ,Plant science ,Cupressaceae ,biology ,Ecology ,Botany ,Genetics ,Forestry ,biology.organism_classification ,Taiwania cryptomerioides - Abstract
The genetic diversity and differentiation of five populations of Taiwania cryptomerioides Hayata in mainland China were investigated using inter-simple sequence repeats (ISSR). In comparison with other coniferous species, T. cryptomerioides from mainland China possesses little genetic variation, particularly at the level of individual populations (the percentage of polymorphic loci, Nei’s gene diversity and Shannon’s indices of diversity at the species and population levels are 38.02%, 0.1326, 0.1986 and 9.27%, 0.035, 0.0518 respectively). In contrast, the level of population differentiation is much higher (GST: 0.7269; Shannon’s genetic differentiation: 0.7392; Hickory è B: 0.668; AMOVA genetic differentiation: 72.37%). The genetic divergence of pairs of populations was not significantly correlated with the geographical distance separating them. Current patterns of genetic variation were related to biogeographic history and the small population size. On the basis of these findings, we discuss the development of conservation strategies for this endangered species.
- Published
- 2008
9. Low genetic diversity and significant population structuring in the relict Amentotaxus argotaenia complex (Taxaceae) based on ISSR fingerprinting
- Author
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Tsai Wen Hsu, Zhong Chao Li, Xian Long Zhou, Xue-Jun Ge, Tzen Yuh Chiang, and Barbara A. Schaal
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Genetic diversity ,education.field_of_study ,Polymorphism, Genetic ,Amentotaxus ,biology ,Ecology ,Population ,Minisatellite Repeats ,Sequence Analysis, DNA ,Plant Science ,biology.organism_classification ,Amentotaxus yunnanensis ,Amentotaxus formosana ,Genetic drift ,Evolutionary biology ,Genetic variation ,education ,Phylogeny ,Taxaceae ,Amentotaxus argotaenia - Abstract
Amentotaxus, a genus of the Taxaceae, represents an ancient lineage that has long existed in Eurasia. All Amentotaxus species experienced frequent population expansion and contraction over periodical glaciations in Tertiary and Quaternary. Among them, Amentotaxus argotaenia complex consists of three morphologically alike species, A. argotaenia, Amentotaxus yunnanensis, and Amentotaxus formosana. This complex is distributed in the subtropical region of mainland China and Taiwan where many Pleistocene refugia have been documented. In this study, genetic diversity and population structuring within and between species were investigated based on the inter-simple sequence repeats (ISSR) fingerprinting. Mean genetic diversity within populations was estimated in three ways: (1) the percentage of polymorphic loci out of all loci (P) (2) Nei's unbiased expected heterozygosity (He), and (3) Shannon's index of phenotypic diversity. For a total of 310 individuals of 15 populations sampled from the three species, low levels of ISSR genetic variation within populations were detected, with P=4.66-16.58%, He=0.0176-0.0645 and Hpop=0.0263-0.0939, agreeing with their seriously threatened status. AMOVA analyses revealed that the differences between species only accounted for 27.38% of the total variation, whereas differences among populations and within populations were 57.70 and 14.92%, respectively, indicating substantial isolation between the patch-like populations. A neighbor-joining tree identified a close affinity between A. yunnanensis and A. formosana. Genetic drift due to small population size, plus limited current gene flow, resulted in significant genetic structuring. Low levels of intra-populational genetic variation and considerable inter-populational divergence were also attributable to demographic bottlenecks during and/or after the Pleistocene glaciations.
- Published
- 2005
10. Genetic diversity of Calocedrus macrolepis (Cupressaceae) in southwestern China
- Author
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Zhong Chao Li, Xue-Jun Ge, Gang Hao, De Lian Wang, and Tzen Yuh Chiang
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Genetic diversity ,Small population size ,Calocedrus macrolepis ,Biology ,biology.organism_classification ,Biochemistry ,Diversity index ,Genetic distance ,Genetic drift ,Geographical distance ,Evolutionary biology ,Genetic variation ,human activities ,Ecology, Evolution, Behavior and Systematics - Abstract
Genetic diversity and differentiation among five populations of Calocedrus macrolepis in southwestern China were investigated using inter-simple sequence repeats (ISSR) markers. Low genetic diversity was revealed, with mean percentage of polymorphic loci at P=26.9% and average expected heterozygosity of HE=0.1114. Low levels of genetic differentiation among populations were detected based on Nei’s genetic diversity analysis (4.2%), Shannon’s diversity index (2.7%), and AMOVA (4.1%). Pairwise genetic identity (I) values among populations ranged from 0.9899 to 0.9964, with a mean of 0.9932. There was no correlation between genetic and geographic distance among the populations studied. Possible genetic bottlenecks during Quaternary glaciations coupled with effects of genetic drift that shaped scattered and small populations were postulated to be the main reasons for the low genetic diversity in Calocedrus macrolepis.
- Published
- 2004
11. Development and characterization of microsatellite markers for Camellia nitidissima
- Author
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Hui Tang, Wei Jiqing, Zong-You Chen, Xiao Wei, Zheng-Feng Wang, Zhong-Chao Li, and Yun-Sheng Jiang
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Conservation genetics ,Genetics ,biology ,Camellia nitidissima ,Biodiversity ,Endangered species ,food and beverages ,Zoology ,Population genetics ,biology.organism_classification ,Genetic marker ,Microsatellite ,Theaceae ,Ecology, Evolution, Behavior and Systematics - Abstract
Camellia nitidissima Chi (Theaceae), a rare and famous plant with golden-yellow flowers, narrowly distributes in Southwest China and North Vienam. It is now endangered and its distribution is ongoing shrinked due to deforestation and collection of seeds for horticulture. From repetitive DNA enriched libraries, we reported here the development and characterization of ten microsatellite markers for this species. The number of alleles ranged from 5 to 12. Observed and expected heterozygosities ranged from 0.4583 to 0.9474, and 0.6976 to 0.9033, respectively. These ten polymorphic microsatellite loci is the first set of microsatellite markers for C. nitidissima, and they will be used for future study of conservation genetics of this species.
- Published
- 2009
12. Isolation and characterization of microsatellite markers for Primulina tabacum, a critically endangered perennial herb
- Author
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Zhong-Chao Li, Kai-Ming Liang, Hai Ren, Qianmei Zhang, Zheng-Feng Wang, and Wanhui Ye
- Subjects
Critically endangered ,Genetic marker ,Genetic structure ,Botany ,Genetics ,Endangered species ,Biodiversity ,Microsatellite ,Locus (genetics) ,Allele ,Biology ,Ecology, Evolution, Behavior and Systematics - Abstract
Primulina tabacum is a rare and endangered perennial herb with highly restricted limestone distribution in southern China. To enrich our scientific conservation for this species, we developed ten microsatellite markers using repetitive DNA enriched libraries. The number of alleles per microsatellite locus varied from two to six. The expected (HE) and observed (HO) heterozygosities varied from 0.4059 to 0.7294 and from 0.1364 to 0.5217, respectively. These markers will be employed in future studies of genetic structure in P. tabacum.
- Published
- 2008
13. Identification and characterization of EST-SSRs and cpSSRs in endangered Cycas hainanensis
- Author
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Hong-Lin Cao, Zhong-Chao Li, Shao-Lin Peng, Wanhui Ye, and Zheng-Feng Wang
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Cycas hainanensis ,biology ,Botany ,Population structure ,Genetics ,Endangered species ,food and beverages ,Microsatellite ,Identification (biology) ,Genetic variability ,biology.organism_classification ,Ecology, Evolution, Behavior and Systematics - Abstract
We report on the identification and characterization of six EST-linked simple sequence repeats (EST-SSRs) and chloroplast SSRs (cpSSRs) in endangered Cycas hainanensis. The number of alleles ranged from two to eight for EST-SSRs, two to three for cpSSRs. Observed and expected heterozygosities ranged from 0.042 to 0.417 and 0.042 to 0.811 for EST-SSRs, respectively. Expected heterozygosities ranged from 0.156 to 0.457 for cpSSRs. All these markers gave successful cross-species amplification in C. fairylakea. These markers will allow analyses of the baseline genetic variability and population structure of C. hainanensis to provide strategies for effective conservation and management.
- Published
- 2007
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