37 research outputs found

    INTERVAL ANALYSIS METHOD OF RELIABILITY PREDICTION ON AUTOMOTIVE BRAKE SYSTEM AND TIRE

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    Fault tree of automotive brake system and tire were set up according to their typical failure modes. We use the likelihood function and belief function of D-S theory respectively as the fault tree to analyze the upper and lower bounds of bottom event fault probability interval,we also apply the interval analysis theory to construct the AND operator,OR operator,and we conduct numerical computation on bottom event fault probability interval to solve the quantitative calculation problem of fault tree,thus to obtain probability interval of the top event fault,and reliability of automobile tire and brake system are analyzed and predicted. The calculation results show that this method is effective and feasible, which provide a reference design for improvement and the adjustment of automotive brake system and tire

    VIBRATION RESPONSE ANALYSIS OF FIVE-DEGREE-FREEDOM VEHICLE WITH STOCHASTIC STRUCTURAL PARAMETERS

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    In order to study effect that road roughness generated random excitation on the structural parameters of nonlinear vibration response of the vehicle system,random structural parameters of five- degrees-freedom nonlinear vehicle model were established,and the model parameters are considered as random variables,under the premise that between the tire and the body presence nonlinear spring to study the random vibration response of the model under random excitation. Road irregularity is considered to be a white noise process to establish the mechanical model,the nonlinear vehicle system was linearized by the energy difference method,a stationary covariance matrix for the random vibration responses was obtained by solving the Lyapunov equations,and the stable equivalent linear system parameters of vehicle were gained through iteration. The example calculation results show that this method can improve the accuracy and efficiency of computation

    Integrative Analysis of Metabolome and Transcriptome Revealed Lutein Metabolism Contributed to Yellow Flower Formation in <i>Prunus mume</i>

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    Prunus mume is a famous ornamental woody tree with colorful flowers. P. mume with yellow flowers is one of the most precious varieties. Regretfully, metabolites and regulatory mechanisms of yellow flowers in P. mume are still unclear. This hinders innovation of flower color breeding in P. mume. To elucidate the metabolic components and molecular mechanisms of yellow flowers, we analyzed transcriptome and metabolome between ‘HJH’ with yellow flowers and ‘ZLE’ with white flowers. Comparing the metabolome of the two varieties, we determined that carotenoids made contributions to the yellow flowers rather than flavonoids. Lutein was the key differential metabolite to cause yellow coloration of ‘HJH’. Transcriptome analysis revealed significant differences in the expression of carotenoid cleavage dioxygenase (CCD) between the two varieties. Specifically, the expression level of PmCCD4 was higher in ‘ZLE’ than that in ‘HJH’. Moreover, we identified six major transcription factors that probably regulated PmCCD4 to affect lutein accumulation. We speculated that carotenoid cleavage genes might be closely related to the yellow flower phenotype in P. mume. Further, the coding sequence of PmCCD4 has been cloned from the ‘HJH’ petals, and bioinformatics analysis revealed that PmCCD4 possessed conserved histidine residues, ensuring its enzymatic activity. PmCCD4 was closely related to PpCCD4, with a homology of 98.16%. Instantaneous transformation analysis in petal protoplasts of P. mume revealed PmCCD4 localization in the plastid. The overexpression of PmCCD4 significantly reduced the carotenoid content in tobacco plants, especially the lutein content, indicating that lutein might be the primary substrate for PmCCD4. We speculated that PmCCD4 might be involved in the cleavage of lutein in plastids, thereby affecting the formation of yellow flowers in P. mume. This work could establish a material and molecular basis of molecular breeding in P. mume for improving the flower color

    The first report of Cryptosporidium andersoni in horses with diarrhea and multilocus subtype analysis

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    Abstract Background Horses interact with humans in a wide variety of sport competitions and non-competitive recreational pursuits as well as in working activities. Cryptosporidium spp are one of the most important zoonotic pathogens causing diarrhea of humans and animals. The reports of Cryptosporidium in horses and the findings of zoonotic Cryptosporidium species/genotypes show a necessity to carry out molecular identification of Cryptosporidium in horses, especially in diarrheic ones. The aim of the present study was to understand Cryptosporidium infection and species/genotypes in diarrheic horses, and to trace the source of infection of horse-derived Cryptosporidium isolates at a subtype level. Findings Fecal specimens of 29 diarrheic adult horses were collected in Taikang County in northeastern China’s Heilongjiang Province. Cryptosporidium oocysts were concentrated by Sheather’s sugar flotation technique, and then examined by a bright-field microscope. Meanwhile, all the specimens were subjected to PCR amplification of the small subunit (SSU) rRNA gene of Cryptosporidium. C. andersoni isolates were further subtyped by multilocus sequence typing (MLST) at the four microsatellite/minisatellite loci (MS1, MS2, MS3 and MS16). One and two Cryptosporidium-positive isolates were obtained in horses by microscopy and by PCR, respectively. The two C. andersoni isolates were identified by sequencing of the SSU rRNA gene of Cryptosporidium. Both of them were identical to each other at the MS1, MS2, MS3 and MS16 loci, and MLST subtype A4,A4,A4,A1 was found here. Conclusions This is the first report of C. andersoni in horses. The fact that the MLST subtype A4,A4,A4,A1 was reported in cattle suggests a large possibility of transmission of C. andersoni between cattle and horses

    Effect of promoters on the selective hydrogenolysis of glycerol over Pt/W-containing catalysts

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    Diverse promoters, including noble metals (such as Ru, Ir and Rh) and transition metal oxides (such as Re, La, Fe, Zr, Sn and Ce oxides) were introduced into Pt/WOx and Pt/WOx/Al2O3 catalysts to investigate the ability of these promoters to modify activity and selectivity during glycerol hydrogenolysis to 1,3-propanediol. Among these, La exhibited the greatest promotional effect; the introduction of 0.1% La to the Pt/WOx improved activity, selectivity and stability, although the significant increase in selectivity came at the cost of a slight activity loss in the case of the Pt/WOx/Al2O3 catalyst. Transmission electron microscopy, high angle annular dark field scanning tunneling electron microscopy and NH3-temperature programmed desorption all demonstrated that the introduction of La generates a greater quantity of acidic sites on the catalyst surface, and that the majority of the La species are associated with Pt particles. Most of the other additives resulted in only minimal improvements or even detrimental effects with regard to both activity and selectivity, although some appear to improve the stability of the catalyst. (C) 2016, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved

    A Dual-Wavelength Phosphorescent Anti-Counterfeiting Copolymer Containing Eu(III) and Tb(III)

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    The anti-counterfeiting technology of banknotes, bills and negotiable securities is constantly copied, and it is urgent to upgrade its anti-counterfeiting technology. In view of the defect of easy replication of single-wavelength anti-counterfeiting technology, the bonded copolymer PMEuTb was synthesized, employing the technique of first coordination and then polymerization. The molecular structure of copolymer PMEuTb was confirmed by infrared spectrum and UV-vis absorption spectrum. The internal mechanism of negative correlation between initiator concentration and number-average molecular weight Mn of the copolymer was revealed, and the positive correlation between Mn and luminescent behavior of the copolymer was analyzed. The luminescent properties of copolymer PMEuTb with initiator amount of 0.1% were investigated, the copolymer PMEuTb exhibits dual-wavelength emission of green light and red light under the excitation of ultraviolet light at 254 nm and 365 nm. The copolymer has the lifetime of 1.083 ms at 5D4&ndash;7F5 transition and 0.665 ms at 5D0&ndash;7F2 transition, which belongs to phosphorescent emitting materials. The copolymer remains stable at 240 &deg;C, and variable temperature photoluminescent spectra demonstrate the luminescent intensity remains 85% at 333 K, meeting the requirements of room temperature phosphorescent anti-counterfeiting materials. The luminescent patterns made by standard screen printing display the green and cuticolor logo at 254 nm and 365 nm, respectively, indicating that the bonded phosphors PMEuTb has potential application in phosphorescent anti-counterfeiting

    effectofpromotersontheselectivehydrogenolysisofglyceroloverptwcontainingcatalysts

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    Diverse promoters, including noble metals (such as Ru, Ir and Rh) and transition metal oxides (such as Re, La, Fe, Zr, Sn and Ce oxides) were introduced into Pt/WOx and Pt/WOx/Al2O3 catalysts to investigate the ability of these promoters to modify activity and selectivity during glycerol hydrogenolysis to 1,3-propanediol. Among these, La exhibited the greatest promotional effect; the introduction of 0.1% La to the Pt/WOx improved activity, selectivity and stability, although the significant increase in selectivity came at the cost of a slight activity loss in the case of the Pt/WOx/Al2O3 catalyst. Transmission electron microscopy, high angle annular dark field scanning tunneling electron microscopy and NH3-temperature programmed desorption all demonstrated that the introduction of La generates a greater quantity of acidic sites on the catalyst surface, and that the majority of the La species are associated with Pt particles. Most of the other additives resulted in only minimal improvements or even detrimental effects with regard to both activity and selectivity, although some appear to improve the stability of the catalyst. (C) 2016, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved

    ptnbwoxforthechemoselectivehydrogenolysisofglycerolto13propanediolnbdopantpacifyingtheoverreductionofwoxsupports

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    Selective hydrogenolysis of glycerol to 1,3-propanediol (1,3-PD) is an important yet challenging method for the transformation of biomass into value-added chemicals due to steric hindrance and unfavorable thermodynamics. In previous studies, chemoselective performances were found demanding and sensitive to H-2 pressure. In this regard, we manipulate the chemical/physical characteristics of the catalyst supports via doping Nb into WOx and prepared 1D needle-, 2D flake-, and 3D sphere-stack mesoporous structured Nb-WOx, with increased surface acid sites. Moreover, Nb doping can successfully inhibit the over-reduction of active W species during glycerol hydrogenolysis and substantially broaden the optimal H-2 pressure from 1 to 5 MPa. When Nb doping is 2%, supported Pt catalysts showed promising performance for the selective hydrogenolysis of glycerol to 1,3-PD over an unprecedentedly wide H-2 pressure range, which will guarantee better catalyst stability in the long run, as well as expand their applications to other hydrogen-related reactions. (C) 2018, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved

    Experimental Investigation of Impactor Diameter Effect on Low-Velocity Impact Response of CFRP Laminates in a Drop-Weight Impact Event

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    The present study delved into the effect of impactor diameter on low velocity impact response and damage characteristics of CFRP. Moreover, the phased array ultrasonic technique (PAUT) was adopted to identify the impact damages based on double-sided scanning. Low-velocity impact tests were carried out using three hemispherical impactors with different diameters. The relationship of impact response and impactor diameters was analyzed by ultrasonic C-scans and S-scans, combined with impact response parameters. Subsequently, the damage characteristics were assessed in terms of dent depth, delamination area and extension shape via the thickness, and the relationships between absorbed energy, impactor displacement, dent depth and delamination area were elucidated. As revealed from experiment results, double-sided PAUT is capable of representing the internal damage characteristics more accurately. Moreover, the impactor diameter slightly affects the impact response under small impact energy, whereas it significantly affects the impact response under large impact energy

    ptnbwoxforthechemoselectivehydrogenolysisofglycerolto13propanediolnbdopantpacifyingtheoverreductionofwoxsupports

    No full text
    Selective hydrogenolysis of glycerol to 1,3-propanediol (1,3-PD) is an important yet challenging method for the transformation of biomass into value-added chemicals due to steric hindrance and unfavorable thermodynamics. In previous studies, chemoselective performances were found demanding and sensitive to H-2 pressure. In this regard, we manipulate the chemical/physical characteristics of the catalyst supports via doping Nb into WOx and prepared 1D needle-, 2D flake-, and 3D sphere-stack mesoporous structured Nb-WOx, with increased surface acid sites. Moreover, Nb doping can successfully inhibit the over-reduction of active W species during glycerol hydrogenolysis and substantially broaden the optimal H-2 pressure from 1 to 5 MPa. When Nb doping is 2%, supported Pt catalysts showed promising performance for the selective hydrogenolysis of glycerol to 1,3-PD over an unprecedentedly wide H-2 pressure range, which will guarantee better catalyst stability in the long run, as well as expand their applications to other hydrogen-related reactions. (C) 2018, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved
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