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Search Results: 1 - 10 of 120152 matches for " Yongxiang Wang "
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Density Evolution of the Surface Short Fatigue Cracks of 1Cr18Ni9Ti Pipe-Weld Metal
Density Evolution of the Surface Short Fatigue Cracks of 1Cr18Ni9Ni Pipe—Weld Metal

Yongxiang ZHAO,Jinnuo WANG,Qing GAO,

材料科学技术学报 , 2002,
Abstract: The evolutionary density and the scatter of densities of the short fatigue cracks on the surface of 1Cr18Ni9Ti pipe-weld metal were observed by local and overall viewpoints, respectively. The local viewpoint, which is in accordance with a so-called ``effectively short fatigue crack criterion", paid attention to the dominant effective short fatigue crack (DESFC) initiation zone and the zones ahead of the DESFC tips. The overall viewpoint focused on the whole test piece of specimen. The results revealed that the density and scatter evolution exhibited a significant character of microstructural short crack and physical short crack stages. The evolutionary behavior by the local viewpoint was sensitive to the increase of DESFC size and tip location. The mechanism of the short crack growth associated with the general test observations that the DESFC acted gradually as a long crack and the scatter of DESFC growth rates tended gradually to that of a long crack was well revealed. Intrinsic causes of the random cyclic strain-life relations and stress-strain responses are appropriately given. In contrast, the evolutionary behavior by the overall viewpoint was non-sensitive and violated the general test observations. Therefore, the intrinsic localization and randomization of material evolutionary fatigue damage should be more appropriately revealed from the observations by the local viewpoint.
Fluorescent detection of singlet oxygen: Amplifying signal transduction and improving sensitivity based on intramolecular FRET of anthryl appended porphyrins
MingXu You,YongXiang Wang,Hao Wang,RongHua Yang
Chinese Science Bulletin , 2011, DOI: 10.1007/s11434-011-4736-0
Abstract: Two new anthryl-appended porphyrin dyads have been synthesized and used as highly selective and sensitive fluorescence probes for singlet oxygen (1O2). The design strategy for the probes is directed by the idea of intramolecular fluorescence resonance energy transfer (FRET) interactions and carried out by incorporation of an electron-rich fluorophore (porphyrin) with a reactive anthracene for 1O2. The molecular recognition is based on the specific interaction of 1O2 with the inner anthracene moiety, and the signal reporter for the recognition process is the porphyrin fluorescence. As a result of overlap of the emission band of the anthracene with the absorbance band of the porphyrin, intramolecular FRET occurs between the anthracene (donor) and the porphyrin (acceptor). The effective light absorbed by the porphyrin and, concomitantly, the emitted light intensity are thus modulated by the emission intensity of the anthracene. Upon reaction with reactive oxygen species such as hydrogen peroxide, hypochlorite, superoxide, hydroxyl radicals, and 1O2, the probes exhibit a selective response toward 1O2. In addition, significant amplification of the signal transducer is observed. The feasibility of the design was demonstrated by monitoring the 1O2 generated from a MoO 4 2 /H2O2 system. The results clearly demonstrate that the synthesized probes exhibit both high selectivity and high sensitivity for 1O2. The fluorescence reaction and signal amplification mechanism of the system were both discussed, clearly confirming that the introduction of electron-rich porphyrin units into the 9,10-positions of anthracene can improve the response sensitivity and activate the probe’s reactivity toward 1O2.
Middle Pleistocene mammalian fauna of Shanyangzhai cave in Qinhuangdao area, China and its zoogeographical significance
YunXiang Zhang,YongXiang Li,Wei Wang,HuJun Gong
Chinese Science Bulletin , 2010, DOI: 10.1007/s11434-009-0360-7
Abstract: The mammalian fauna with clear characteristics of transitional region has been found in the Shanyangzhai cave of the Qinhuangdao area where the three Chinese zoogeographical regions (the Northeast region, the North region and the Mengxin region) join. Abundant fossils mainly are small mammals. The fauna includes typical species derived from three zoogeographical regions and can be compared with the middle Pleistocene faunas found in both the Zhoukoudian (the North region) and the Jinniushan (Northeast region) faunas. Of 53 kinds of mammals identified at the site, 38 kinds can be seen on the list of the middle Pleistocene Zhoukoudian and the Jinniushan faunas, of which 29 kinds are the same as those in the Zhoukoudian fauna and 25 are in the Jinniushan fauna, 7 in the Salawusu fauna and account for 76%, 66% and 18% of the total, respectively. It is suggested based on the consistence of the constitution of the fauna and its recent zoogeographic division that the three regions in north China could be initially formed during the middle Pleistocene.
The Impact of Atmosphere Circular System on Coupling Features of Spring Net Primary Productivity with Precipitation in East Asia
Wu Gang,Wang Yongxiang,Yu Deyong,Pan Yaozhong
Pakistan Journal of Biological Sciences , 2007,
Abstract: In many East Asia regions, spring (from March to May) precipitation is an important restricting factor to vegetation growth. By analyzing the coupling features of spring NPP with precipitation, the result was found that the response features of NPP to precipitation were mainly embodied within the leading six NPP-precipitation paired-modes. The explanation rates of the leading six paired-modes to the covariance of NPP-precipitation were 42.91, 23.29, 9.96, 5.60, 5.04 and 3.95%, respectively and total to 90.75%. The temporal correlation coefficients of the leading six paired-modes were 0.830, 0.889, 0.841, 0.747, 0.912 and 0.923, respectively and all the correlations were significant at the level of 0.001. In some high altitude regions, there was no obviously corresponding relationship between NPP and precipitation in the leading two paired-modes and the reason of it may be that spring temperature was the main restricting factor to NPP. In middle and low altitude regions, the effect of precipitation on NPP was relatively more notable. Nine atmospheric circulation factors in spring affected the patterns of NPP and precipitation greatly and the affected regions with explanation rate to precipitation and NPP changes over 50% shared 65.58 and 60.41% to the whole study area, respectively.
Interactive Effects of Selenium and Mercury on Their Uptake by Rice Sedlings
Xinbin Zhou,Wenhua Wang,Shuhui Yu,Yongxiang Zhou
Research Journal of Applied Sciences, Engineering and Technology , 2013,
Abstract: In this study, a new modeling method based on metasynthesis is proposed from the macro and micro levels. And the system analysis and design agent-oriented based on POMDP are provided in the same time. Finally, the two case studies are given and the experimental results have shown efficiency and rationality of this modeling method. Under greenhouse conditions, rice was taken as test object and the interactive effects of selenium and mercury in rice seedlings grown in solution culture were researched by the use of quadratic-orthogonal-rotation-combination design. The results showed that low mercury concentration (<30 μg/L) promoted selenium absorption in rice roots and shoots, which may be associated with selenium’s favorable effect on plant. Higher mercury concentration (>30 μg/ L) reduced selenium accumulation in rice roots and stems, as well as the transfer of selenium to the rice shoot. When the mercury concentration was fixed at 100 μg/L, Se in the growth medium significantly reduced Hg accumulation in the roots and the effect of Se on Hg accumulation in shoots displayed a similar pattern. However, with the increase of selenium concentration of the solution, the Hg transfer coefficient from the root to the shoot remained unchanged.
Fabrication of Heparinized Mesoporous Silica Nanoparticles as Multifunctional Drug Carriers
Yongxiang Zhang,Xinmin Liu,Yizhong Lu,Jincai Wang
Journal of Chemistry , 2013, DOI: 10.1155/2013/430459
Positive Periodic Solutions of Second-Order Differential Equations with Delays
Yongxiang Li
Abstract and Applied Analysis , 2012, DOI: 10.1155/2012/829783
Abstract: The existence results of positive ω-periodic solutionsare obtained for the second-order differential equation with delays ?
Existence of Positive Solutions for a Fourth-Order Periodic Boundary Value Problem
Yongxiang Li
Abstract and Applied Analysis , 2011, DOI: 10.1155/2011/826451
Abstract: The existence results of positive solutions are obtained for the fourth-order periodic boundary value problem (4)?
Four Eremophilane Sesquiterpenes from the Mangrove Endophytic Fungus Xylaria sp. BL321
Yongxiang Song,Jiajian Wang,Hongbo Huang,Lin Ma,Jun Wang,Yucheng Gu,Lan Liu,Yongcheng Lin
Marine Drugs , 2012, DOI: 10.3390/md10020340
Abstract: Three new eremophilane sesquiterpenes ( 1– 3) were isolated from the mangrove endophytic fungus Xylaria sp. BL321 together with 07H239-A ( 4), a known analogue of the new compounds. The structures of these compounds were elucidated by analysis of their MS, 1D and 2D NMR spectroscopic data. Compound 4 showed activation activity on α-glucosidase at 0.15 μM (146%), and then, 4 gradually produced inhibitory activity on α-glucosidase with increasing concentration, and the IC 50 value is 6.54 μM.
Aeromonas haianensis, Sp. Nov., from Eels and Humans
Guanghe Wang,Weihua Chu,Chu Weihua,Jian Wang,Yongxiang Zhu,Xiaoming Qian
Journal of Fisheries International , 2012,
Abstract: Ten strains of unidentified bacteria were isolated from diseased eels and patients with diarrhea in Haian County, Jiangsu Province. All isolates were Gram-negative motile rods growing in non-salt peptone medium at 37 C. They were oxidase positive, glucose fermenting and produced a brown pigment. The bacteria were resistant to O/129. The bacteria were identified as belonging to Aeromonas; some phenotype characteristics were different from these of the reported Aeromonas species. DNA-DNA hybridization studies showed that DNA of strain CCTCC AB97026 was 93 and 89% similar to that of strain 95-72, 96-109 and showed 63% relatedness to Aeromonas veronii, which is below the cut-off value for species differentiation. The determination of mol% G+C, DNA-DNA hybridization and 16S rRNA gene sequencing and fatty acids analysis indicated that these bacteria constitute a new Aeromonas species. These bacteria were susceptible to norfloxacin, furazolidone, nutgall and rhubarb and resisted to penicillin and SMZ. The LD50 for mice and eel is 3.9 106 and 1.2 105 cfu, respectively. The bacterium had some virulence factors, such as type IV pilli, HEC toxin and extracellular proteinase. All the above data and the epidemiological information indicated that the new bacterium was pathogenic to eel and humans. For the new species, the name of Aeromonas haianensis has been proposed because the bacteria were all isolated from Haian County, Jiangsu Province, China. The type strain is CCTCC AB97026T (=IFO16641=strain95-173).
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