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Search Results: 1 - 10 of 24028 matches for " JIANG Yongdong "
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Occurrence of Sciadopitys-like fossil wood (Coniferales) in the Jurassic of western Liaoning and its evolutionary implications
ZiKun Jiang,YongDong Wang,ShaoLin Zheng,Wu Zhang,Ning Tian
Chinese Science Bulletin , 2012, DOI: 10.1007/s11434-011-4850-z
Abstract: The genus Sciadopitys, containing a single species (S. verticillata), is the only extant representative of the Family Sciadopityaceae (Coniferales), and is a remarkable living fossil. Although some leafy fossils have been ascribed to Sciadopityaceae, fossil xylem material with a close affinity to this family is very rare, and there have been no fossils found showing both pith and primary xylem structures, which are of great importance for wood identification. Thus, it has been difficult to use fossils for the understanding of wood anatomy evolution in the sciadopityaceous plants over geological time. In this note we briefly report on Sciadopitys-like fossil wood found in the Middle Jurassic of western Liaoning, which bears well-preserved Protosciadopityoxylon-type secondary xylem, endarch primary xylem and heterogeneous pith. This is the first report of fossil specimens of the Sciadopityaceae with such detailed preservation of wood structures. The discovery provides precise anatomical evidence for reconstructing the evolutionary history and geographical distribution of Sciadopityaceae, as well as contributing to understanding of the fossil diversity of the Jurassic Yanliao Flora in northern China.
Stable carbon isotope compositions of isoprenoid chromans in Cenozoic saline lacustrine source rocks from the Western Qaidam Basin, NW China: Source implications
YongDong Zhang,AiZhu Jiang,YongGe Sun,LiuJuan Xie,PingXia Chai
Chinese Science Bulletin , 2012, DOI: 10.1007/s11434-011-4899-8
Abstract: Although the distribution of mono-, di- and trimethylated 2-methyl-2-(4,8,12-Trimethyltrideeyl) chromans (MTTCs) is well understood as an indicator of water salinity, their origin and formation mechanism are still ambiguous and under debate. In this paper, abnormally high levels of MTTCs were detected in Cenozoic saline lacustrine source rocks from the Western Qaidam Basin. Using a two-step column chromatography method, the MTTCs and naphthalenes were separated from other aromatic compounds and concentrated in one fraction, so that the stable carbon isotope compositions of these compounds could be accurately measured. Similar carbon isotope ratios for the mono-, di- and trimethylated 2-methyl-2-(4,8,12-Trimethyltrideeyl) chromans in a given sample suggest the MTTCs may share the same biological source(s). The MTTCs from the Western Qaidam Basin have similar carbon isotope compositions to primary producer-derived pristane and phytane. However, the δ 13C values for the MTTCs showed significant differences with other primary producers-derived biomarkers (e.g. C27 and C29 steranes), probably indicating a distinct microalgae source from specific niches for the MTTC compounds. We speculate that the MTTCs distribution patterns may be controlled by the water chemistry dynamics in niches, which, in turn, is affected by hypersaline bottom water.
The occurrence and significance of C25HBI in Cenozoic saline lacustrine source rocks from the Western Qaidam Basin, NW China
YongDong Zhang,YongGe Sun,LiuJuan Xie,AiZhu Jiang,PingXia Chai
Chinese Science Bulletin , 2011, DOI: 10.1007/s11434-011-4430-2
Abstract: The saline lacustrine deposit of the Oligocene Lower Ganchaigou Formation is the main source rock for the Western Qaidam Basin, NW China. In this study, abundant highly branched isoprenoids with 25 carbon atoms (C25HBI) were detected in the upper section of the Lower Ganchaigou Formation. C25HBI is a biomarker for diatoms, and can provide information regarding biogeochemical processes during production and preservation of sedimentary organic matter. The carbon isotopic values of C25HBI in these source rocks were in the range of 18‰ to 20‰. The relative enrichment in 13C of C25HBI suggests that these isoprenoids were derived from diatom blooms. In this case, the diatoms used HCO3 as an additional carbon source to dissolved CO2 in water column due to their high biological productivity. Conversely, the diatom blooms indicated an abundant nutrient supply to the environment and high primary productivity. Thus, the occurrence of 13C-enriched C25HBI could be an ideal marker for good source rocks. The decreased concentration of CO2 (aq) in the water column induced by diatom blooms can result in an enrichment in 13C of organic matter synthesized by primary producers. This may be a possible reason for the occurrence of 13C-enriched organic matter in the Cenozoic source rocks of the Western Qaidam Basin. Previous studies have shown that the high carbon number n-alkanes sourced from diatoms have no carbon preference. Hence, the sources of n-alkanes in regional source rocks are complex, and should be considered when discussing the sources of organic matter in future studies.
A Self-Similar Call Admission Control Algorithm in WiMAX  [PDF]
Yongdong Hu, Guoxin Wu
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2016, DOI: 10.4236/ijcns.2016.95016
Abstract:

Modelling WiMAX network traffic based on the self-similarity character is better than the traditional model based on the Poisson process, because the former can provide more accurate calculation for effective bandwidth. In this paper we propose a WiMAX network traffic model based on M/Pareto model to describe its self-similarity character. Then we deduce the average transmission rate and the variance coefficient for the FBM traffic model by the M/Pareto model, and get the Hurst parameter of the FBM traffic model by statistical analysis method. By the FBM traffic model we get a formula for calculating the effective bandwidth. Accordingly, we propose a modified self-similar call admission control algorithm (SS-CAC). SS-CAC can avoid measuring the parameter values of FBM traffic flow to do call admission control. Simulation results show that SS-CAC greatly reduces the call blocking rate and improves the bandwidth utilization.

A miRNA Binding Site Single-Nucleotide Polymorphism in the 3′-UTR Region of the IL23R Gene Is Associated with Breast Cancer
Lihong Wang, Wei Liu, Wei Jiang, Jing Lin, Yongdong Jiang, Bo Li, Da Pang
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0049823
Abstract: Background Research into the etiology of breast cancer has recently focused on the role of the immunity and inflammation. Interleukin-23 and its receptor (IL23R) guide T cells towards the Th17 phenotype. IL23R single nucleotide polymorphisms (SNPs) have been shown to be associated with digestive system cancers. To evaluate the influences of IL23R gene polymorphisms on the risk of sporadic breast cancer, a case-control study was conducted in Chinese Han women. Methodology and Principal Findings We genotyped two tag SNPs (rs10889677 in the 3′-UTR region and nonsynonymous variants rs1884444 in exon 2) in IL23R gene of 491 breast cancer patients and 502 matched healthy controls. The genotypes were determined using the SNaPshot technique. The differences in the genotypic distribution between breast cancer patients and healthy controls were analyzed with the Chi-square test for trends. For rs10889677 in IL23R, the frequencies of the AA genotype and the A allele were statistical significant higher in breast cancer patients than in controls (P = 0.0084 and P = 0.0171, respectively), whereas the C allele was associated with an earlier age of breast cancer onset (50.6 years for AA, 48.7 years for AC and 46.0 years for CC (P = 0.0114)) in case-only study. The clinical features analysis demonstrated significant associations between rs1884444 in IL23R and human epidermal growth factor receptor 2 (Her-2) and tumor size status. Conclusions and Significance Our results suggest that a miRNA binding site SNP in the 3′-UTR region of the IL23R gene may be associated with the risk of breast cancer and contribute to the early development of breast cancer in Chinese women.
Lipids of sulfate-reducing bacteria and sulfur-oxidizing bacteria found in the Dongsheng uranium deposit
Lei Jiang,ChunFang Cai,YongDong Zhang,ShengYi Mao,YongGe Sun,KaiKai Li,Lei Xiang,ChunMing Zhang
Chinese Science Bulletin , 2012, DOI: 10.1007/s11434-011-4955-4
Abstract: U-bearing sandstones from the Dongsheng deposit in Ordos Basin contain abundant C15-C18 fatty acids. The fatty acids may have been derived from modern and ancient organisms including organisms from the intervals of U mineralization. A certain amount of i15:0, a15:0, a17:0 fatty acids coexist with small amounts of i17:1ω7c and 10me16:0, characteristic biomarkers of Desulfovibrio and Desulfobacter sp., respectively. This indicates the existence of sulfate-reducing bacteria (SRB) in the sandstones. The presence of sulfur-oxidizing bacteria (SOB), such as Beggiatoa and Thioploca, is indicated by significant amounts of 16:1ω7c and 18:1ω7c fatty acids. The existence of the SRB in the deposit, as inferred from the fatty acids, is consistent with results from fossilized microorganisms and isotopic compositions of ore-stage pyrite. This suggests that the environment may have been favorable for the SRB to grow since ore formation (9.8–22 Ma). The bacteria may have degraded hydrocarbons directly, or indirectly utilized hydrocarbons degraded by oxic microbes in the deposits. This process may have produced 12C-rich calcite and prominent baseline humps of unresolved complex mixtures (UCM), and 25-demethylated hopanes and tricyclic terpanes. The existence of sulfur-oxidizing bacteria and sulfate-reducing bacteria in the deposit may have resulted in bacterial sulfate reduction to sulfide, re-oxidization of the sulfide to sulfate and subsequent reduction of the sulfate to sulfide. This assertion is supported by ore-stage pyrite with δ 34S values as low as 39.2‰, and the lightest sulfate (about 11‰) measured during the Phanerozoic, a difference of more than 46‰.
EXPERIMENTAL STUDY OF MECHANICAL CHARACTERISTICS OF COAL SPECIMEN IN PROCESS OF UNLOADING CONFINING PRESSURE IN GEOSTRESS FIELD AND ANALYSIS OF GAS SEEPAGE CHARACTERISTICS
地应力场中煤岩卸围压过程力学特性试验研究及瓦斯渗透特性分析

HUANG Qixiang,YIN Guangzhi,JIANG Yongdong,
黄启翔
,尹光志,姜永东

岩石力学与工程学报 , 2010,
Abstract: 应用MTS815力学试验机,对典型煤与瓦斯突出矿井松藻矿务局打通一矿突出煤层原煤制备的型煤试件进行型卸围压试验研究。研究结果表明:(1) 位移控制方式卸围压将导致试件的扩容损伤,力控制方式卸围压将导致试件的破坏。(2) 用位移控制卸围压时,在某一初始围压下,试件的轴向应力随围压的降低而减小,轴压减小的速率越来越大,屈服阶段卸围压曲线比弹性阶段卸围压曲线更加非线性;随初始围压的加大,屈服阶段卸围压曲线的非线形特征更加明显。(3) 用力控制方式卸围压时,在某一初始围压下,试件的轴向应变随围压的降低而增大,轴向应变增大的速率越来越大,屈服阶段卸围压时轴向应变的增大比弹性阶段卸围压时更为迅速;随初始围压的增大,屈服阶段卸围压时试件加速破坏的趋势更加明显;通过轴向应变可计算分析卸围压过程中试验机对试件作的功。根据试验结果,结合全应力–应变过程煤岩瓦斯渗透特性的试验结果,推导出卸围压过程瓦斯渗透特性曲线。根据以上结果,应用损伤理论和Mohr-Coulomb强度理论推导含瓦斯煤岩卸围压过程中试件的损伤和强度的计算公式。研究结果对预测预报瓦斯涌出和预测卸围压过程中煤岩的破坏具有现实指导意义。
Association Analysis of IL-17A and IL-17F Polymorphisms in Chinese Han Women with Breast Cancer
Lihong Wang, Yongdong Jiang, Youxue Zhang, Yuwen Wang, Sunhui Huang, Zhihua Wang, Baoling Tian, Yue Yang, Wei Jiang, Da Pang
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0034400
Abstract: Background Research into the etiology of breast cancer has recently focused on the role of the immunity and inflammation. The proinflammatory cytokines IL-17A and IL-17F can mediate inflammation and cancer. To evaluate the influences of IL-17A and IL-17F gene polymorphisms on the risk of sporadic breast cancer, a case-control study was conducted in Chinese Han women. Methodology and Principal Findings We genotyped three single-nucleotide polymorphisms (SNPs) in IL-17A (rs2275913, rs3819025 and rs3748067) and five SNPs in IL-17F (rs7771511, rs9382084, rs12203582, rs1266828 and rs763780) to determine the haplotypes in 491 women with breast cancer and 502 healthy individuals. The genotypes were determined using the SNaPshot technique. The differences in the genotypic distribution between breast cancer patients and healthy controls were analyzed with the Chi-square test for trends. For rs2275913 in IL-17A, the frequency of the AA genotype was higher in patients than controls (P = 0.0016). The clinical features analysis demonstrated significant associations between IL-17 SNPs and tumor protein 53 (P53), progesterone receptor (PR), human epidermal growth factor receptor 2 (Her-2) and triple-negative (ER-/PR-/Her-2-) status. In addition, the haplotype analysis indicated that the frequency of the haplotype Ars2275913Grs3819025Grs3748067, located in the IL-17A linkage disequilibrium (LD) block, was higher in patients than in controls (P = 0.0471 after correction for multiple testing). Conclusions and Significance Our results suggested that SNPs in IL-17A but not IL-17F were associated with the risk of breast cancer. Both IL-17A and IL-17F gene polymorphisms may provide valuable information for predicting the prognosis of breast cancer in Chinese women.
EXPERIMENTAL STUDY OF EFFECTS OF CYCLIC LOADING AND UNLOADING PORE WATER PRESSURES ON DEFORMATION CHARACTERISTIC OF SANDSTONE
循环加、卸载孔隙水压力对砂岩变形特性影响实验研究

XU Jiang,YANG Hongwei,LI Shuchun,JIANG Yongdong,
许江
,杨红伟,李树春,姜永东

岩石力学与工程学报 , 2009,
Abstract: 利用MTS815岩石力学实验系统对饱和砂岩进行三轴等围压情况下的循环加、卸载孔隙水压力实验.结果表明:压密阶段的加、卸载曲线中出现了很多"Z"状的波动,这些小波的出现没有规律性,初始残余变形比较大,还没有形成明显的滞回曲线.在弹性耦合阶段稳定滞回曲线加载时,应变呈上凹"Z"状波动,在到达上限值前出现拐点,应变达最大值;卸载时,应变呈下凸"Z"状波动,在到达下限值前出现拐点,应变达最小值,该阶段形成稳定的滞回曲线,表现形式由疏变密,稳定滞回曲线包含弹性变形向塑性变形演化.在孔隙水压力的不同上限值和不同幅值区间的耗散能构成不对称"X"形.在加载段,随着孔隙水压力增大,耗散能逐渐减小;卸载段,随着孔隙水压力减小,耗散能逐渐减小."X"形的交点出现的位置和夹角与不同上限值和不同幅值区间有关.在循环加、卸载孔隙水压力作用下,残余应变与循环次数的关系符合乘幂负指数关系.
EXPERIMENTAL STUDY OF MECHANICAL PROPERTY OF SANDSTONE UNDER PORE WATER PRESSURE AND CONFINING PRESSURE
孔隙水压力-围压作用下砂岩力学特性的试验研究

XU Jiang,YANG Hongwei,PENG Shoujian,JIANG Yongdong,ZHANG Yuan,
许江
,杨红伟,彭守建,姜永东,张媛

岩石力学与工程学报 , 2010,
Abstract: 利用MTS815岩石力学测试系统进行两类三轴压缩对比试验:一类是非充水条件下不同围压时的三轴压缩试验;一类是充水条件且围压保持恒定时不同孔隙水压力作用下的三轴压缩试验。基于莫尔–库仑准则,分析非充水条件下,不同围压 作用对细砂岩的峰值破坏强度 及其对应的轴向应变 、剪切强度 和正应力 等参数的影响;充水条件下,围压 恒定时不同孔隙水压力P作用对细砂岩的峰值破坏强度 及其对应的轴向应变 、有效峰值破坏强度 、有效围压 、有效剪切强度 和有效正应力 等参数的影响。研究结果表明:(1) 充水条件下,随着有效围压 的增加,有效峰值破坏强度 呈增大的趋势,但在相同围压条件下随孔隙水压力P的增加有效峰值破坏强度 呈逐渐减小的趋势;(2) 非充水条件下的 曲线和充水条件下的 曲线既可采用一元二次方程拟合,也可采用线性方程拟合,其相应强度曲线均能较好地符合莫尔–库仑准则;(3) 有效剪切强度折减系数K可以较好地表征孔隙水压力P对有效剪切强度 的影响。
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