http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Effect of Blending Modifications for Phenylethynyl-terminated Polyimides
Ping Yu,Min-zhao Xue,Yan-gang Liu,Xue Yang,Li-jing Pan,Yan-li Zhang,Wei Wang 한국섬유공학회 2020 Fibers and polymers Vol.21 No.2
A reactive diluent (ODA-PEPA) and a flexible phenylethynyl-terminated imide oligomer (PEI-PEPA) were designed and synthesized based on the 2,3,3',4'-diphenyl ether tetracarboxylic acid dianhydride (a-ODPA), 3,4'-oxydianiline(3,4'-ODA), and 4-phenylethynylphthalic anhydride (PEPA). Solution blended systems with the addition of 5, 10, and 15 wt% ODA-PEPA to PEI-PEPA oligomer and their cured resin systems were prepared. Results showed that ODA-PEPA is semi-crystalline in nature. The Tg values of cured resins were improved from 273 oC to 280 oC by the addition of ODA-PEPA, due to the higher crosslink densities. In addition, rheological properties of blends showed lower melt viscosity and wider processing window, revealing improved melt processabilities for potential application in making advanced composites. The isothermal viscosity in 280 oC of PEI-PEPA containing 15 wt% ODA-PEPA reactive diluent decreased by two thirds, due to the low molecular weight of ODA-PEPA. The cured blends demonstrated high thermal stability and heat resistance. 5 wt% thermal decomposition temperatures (Td5) of the cured blends were above 549 oC and 547 oC in N2 and air atmosphere, respectively. The char yield reported at 800 oC in N2 atmosphere increased from 58.8% to 63.7 % with the addition of ODAPEPA. Meanwhile, the cured polyimides blends possessed good bond strength (> 9.3 MPa).
Ping-Ping Yuan,Xue-Li Cheng,Hang-Hang Wang,Jian Zhang,Zhong-Xiang Shen,Wei-Xin Ren 국제구조공학회 2021 Smart Structures and Systems, An International Jou Vol.28 No.5
A new method is proposed to improve the accuracy of structural instantaneous frequency (IF) extraction. The proposed method combines a new form of improved generalized S-transform (IGST) and a multi-synchrosqueezing operation. The parameters selection of the window function in IGST is derived through the concentration measure (CM) principle. Then, the multi-synchrosqueezing algorithm is employed to improve energy aggregation of time-frequency analysis (TFA). To verify the effectiveness and accuracy of the proposed improved multi-synchrosqueezing generalized S-transform (IMSSGST), a frequency-modulated multi-component signal is investigated. For structural IF extraction, a two-story shear frame and a threestory steel frame structure are introduced. Furthermore, the IF identification of a seven-story RC shear wall structure is conducted to verified the practicability in actual engineering. Numerical simulation and experimental results show that the proposed method can effectively improve the energy aggregation of TFA and effectively improve the accuracy of IF identification.
Thermal Field Balance and Efficiency Analysis of Plate Type Electromagnetic Induction Heating
Ping Xue,Hao Sun,Bing Li,Hongmin Wang 보안공학연구지원센터 2016 International Journal of Multimedia and Ubiquitous Vol.11 No.2
Owing to flat plate induction heating can’t guarantee to heat equally, especially the existence of no heated zone, it haven’t been used in these industrial fields like SMD which require high accuracy and easy to control while heating. But some places need its characteristic of contact heating, eco-friendly and high efficiency, for this reason, it is fundamental to research the heating style further as well as the no heating zone. Because induction heating is based on eddy current, firstly, the relationship between eddy current and induction heating is explained and several factors which would influence the eddy current are put forward. Then finite element analysis and calculation of eddy current field is mainly done. At last, the conclusion is obtained by analyzing the results of calculation. Due to the analysis above, after improving the structure of the iron plate, the problem of no heating zone is solved. At the same time, the efficiency evaluation is brought out. It can make the following research more easily.
Xue Ping Chen,Jing Sun,Yi Wang,Heng Yang Zhang,Chi Quan He,Xiao Yan Liu,Nai Shun Bu,Xi-En Long 한국미생물학회 2018 The journal of microbiology Vol.56 No.7
Methane production by methanogens in wetland is recognized as a significant contributor to global warming. Spartina alterniflora (S. alterniflora), which is an invasion plant in China’s wetland, was reported to have enormous effects on methane production. But studies on shifts in the methanogen community in response to S. alterniflora invasion at temporal and spatial scales in the initial invasion years are rare. Sediments derived from the invasive species S. alterniflora and the native species Phragmites australis (P. australis) in pairwise sites and an invasion chronosequence patch (4 years) were analyzed to investigate the abundance and community structure of methanogens using quantitative real-time PCR (qPCR) and Denaturing gradient gel electrophoresis (DGGE) cloning of the methyl-coenzyme M reductase A (mcrA) gene. For the pairwise sites, the abundance of methanogens in S. alterniflora soils was lower than that of P. australis soils. For the chronosequence patch, the abundance and diversity of methanogens was highest in the soil subjected to two years invasion, in which we detected some rare groups including Methanocellales and Methanococcales. These results indicated a priming effect at the initial invasion stages of S. alterniflora for microorganisms in the soil, which was also supported by the diverse root exudates. The shifts of methanogen communities after S. alterniflora invasion were due to changes in pH, salinity and sulfate. The results indicate that root exudates from S. alterniflora have a priming effect on methanogens in the initial years after invasion, and the predominate methylotrophic groups (Methanosarcinales) may adapt to the availability of diverse substrates and reflects the potential for high methane production after invasion by S. alterniflora.
Construction of main effects plans orthogonal through the block factor based on level permutation
Xue-Ping Chen,Jinguan Lin,Xing-Fang Huang 한국통계학회 2015 Journal of the Korean Statistical Society Vol.44 No.4
In this paper, We first demonstrate that the orthogonal property of main effects plans orthogonal through the block factor (Bagchi, 2010) remains unchanged under level permutation. However, level permutation of factors could alter their geometrical structures and statistical properties. Hence uniformity is used to further distinguish main effects plans orthogonal through the block factor (POTB). A modified optimization algorithm is proposed to search uniform or nearly uniform POTBs and many new optimal POTBs with lowerdiscrepancy are obtained.
The Effect of Transformation on the Virulence of Streptococcus pneumoniae
Xue-Mei Zhang,Yi-Bing Yin,Dan Zhu,Bao-De Chen,Jin-Yong Luo,Yi-Ping Deng,Ming-Fang Liu,Shu-Hui Chen,Jiang-Ping Meng,Kai Lan,Yuan-Shuai Huang,Ge-Fei Kang 한국미생물학회 2005 The journal of microbiology Vol.43 No.4
Although pneumococcus is one of the most frequently encountered opportunistic pathogen in the world, the mechanisms responsible for its infectiveness have not yet been fully understood. In this paper, we have attempted to characterize the effects of pneumococcal transformation on the pathogenesis of the organism. We constructed three transformation-deficient pneumococcal strains, which were designated as Nos. 1d, 2d, and 22d. The construction of these altered strains was achieved via the insertion of the inactivated gene, comE, to strains 1, 2 and 22. We then conducted a comparison between the virulence of the transformation-deficient strains and that of the wild-type strains, via an evaluation of the ability of each strain to adhere to endothelial cells, and also assessed psaA mRNA expression, and the survival of hosts after bacterial challenge. Compared to what was observed with the wild-type strains, our results indicated that the ability of all of the transformation-deficient strains to adhere to the ECV304 cells had been significantly reduced (p < 0.05), the expression of psaA mRNA was reduced significantly (p < 0.05) in strains 2d and 22d, and the median survival time of mice infected with strains 1d and 2d was increased significantly after intraperitoneal bacterial challenge (p < 0.05). The results of our study also clearly indicated that transformation exerts significant effects on the virulence characteristics of S. pneumoniae, although the degree to which this effect is noted appears to depend primarily on the genetic background of the bacteria.