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1.
The chemisorption properties of N18O adsorption on TiO2(110) surface were investigated by experimental and theoretical methods. The results of temperature programmed desorption (TPD) indicated that the temperatures of the three desorption peaks of the main N2 molecules were at (low) temperature of 230 K, 450 K and (high) temperature of 980 K. This meant that N18O decomposed and recombined during the process of N2 desorption after N18O was exposed. Analysis of the stable combination and orbital theory calculation of the surface reaction of NO adsorption on the TiO2(110) cluster model showed that there was clear preference for the Ti-NO orientation.  相似文献   

2.

Objective

To evaluate the potential adjuvant effect of Agrocybe aegerita lectin (AAL), which was isolated from mushroom, against a virulent H9N2 strain in vivo and in vitro.

Methods

In trial 1, 50 BALB/c male mice (8 weeks old) were divided into five groups (n=10 each group) which received a subcutaneous injection of inactivated H9N2 (control), inactivated H9N2+0.2% (w/w) alum, inactivated H9N2+0.5 mg recombinant AAL/kg body weight (BW), inactivated H9N2+1.0 mg AAL/kg BW, and inactivated H9N2+2.5 mg AAL/kg BW, respectively, four times at 7-d intervals. In trial 2, 30 BALB/c male mice (8 weeks old) were divided into three groups (n=10 each group) which received a subcutaneous injection of inactivated H9N2 (control), inactivated H9N2+2.5 mg recombinant wild-type AAL (AAL-wt)/kg BW, and inactivated H9N2+2.5 mg carbohydrate recognition domain (CRD) mutant AAL (AAL-mutR63H)/kg BW, respectively, four times at 7-d intervals. Seven days after the final immunization, serum samples were collected from each group for analysis. Hemagglutination assay, immunogold electron microscope, lectin blotting, and co-immunoprecipitation were used to study the interaction between AAL and H9N2 in vitro.

Results

IgG, IgG1, and IgG2a antibody levels were significantly increased in the sera of mice co-immunized with inactivated H9N2 and AAL when compared to mice immunized with inactivated H9N2 alone. No significant increase of the IgG antibody level was detected in the sera of the mice co-immunized with inactivated H9N2 and AAL-mutR63H. Moreover, AAL-wt, but not mutant AAL-mutR63H, adhered to the surface of H9N2 virus. The interaction between AAL and the H9N2 virus was further demonstrated to be associated with the CRD of AAL binding to the surface glycosylated proteins, hemagglutinin and neuraminidase.

Conclusions

Our findings indicated that AAL could be a safe and effective adjuvant capable of boosting humoral immunity against H9N2 viruses in mice through its interaction with the viral surface glycosylated proteins, hemagglutinin and neuraminidase.
  相似文献   

3.
The vapor-liquid equilibrium(VLE) properties for the binary and ternary mixtures of CH4,C2H4 and isoC4H10 are of great importance in the recovery of ethylene from mixture containing CH4 and C2H4 with iso-C4H10 as solvent.Hence,Gibbs ensemble Monte Carlo(GEMC) simulations were used to estimate vapor-liquid equilibrium for the binary and ternary mixtures of CH4,C2H4 and iso-C4H10 with the united atom potential NERD model.The selected simulation conditions are based on the experiment in the literature.The results of this work were shown to be in satisfactory agreement with available experimental data and predictions of Peng-Robinson equation of state.The structure of simulated liquid phase is also characterized by radial distribution function(RDF),which contributes to further understanding of the VLE curve of these systems.RDF is not sensitive to the pressure and temperature range.With the increase of pressure or the decrease of temperature,the molecules tend to gather together.  相似文献   

4.
The synthesis of methanol and dimethyl ether (DME) from CO hydrogenation has been investigated on Cu-based catalysts. A series of Cu/ZnO/Al2O3 catalysts were prepared using a solvent-free routine which involved a direct blend of copper/zinc/aluminum salts and citric acid, followed by calcination at 450 °C. The calcination processes were monitored using thermogravimetry differential scanning calorimetry (TG-DSC). Catalysts were further characterized using N2 adsorption, scanning electronic microscopy (SEM), X-ray diffraction (XRD), N2O oxidation followed by H2 titration, and temperature-programmed reduction with H2 (H2-TPR). The reduction processes were also monitored with in-situ XRD. The physicochemical properties of catalysts depended strongly on the types of precursor salts, and catalysts prepared using Al acetate and Cu nitrate as starting materials had a larger surface area, larger exposed metallic copper surface area, and lower reduction temperature. The CO hydrogenation performances of these catalysts were compared and discussed in terms of their structures. Catalysts prepared with copper nitrate, zinc and aluminum acetates exhibited the highest catalytic activity.  相似文献   

5.
Tracing developmental pathways of immigrant-origin adolescents, this 3-year longitudinal study (2012–2015) examined within-person changes in cultural orientations and their consequences for school adjustment. Multivariate latent growth mixture modeling confirmed multiple pathways of integration, revealing variable acculturative changes along dual trajectories of heritage and mainstream orientations among European-origin (N = 592, Mage = 14.45, 55.1% boys) and Turkish- and Moroccan-origin adolescents (N = 1269, Mage = 14.70, 53.1% boys). Two trajectories for European-origin adolescents differed in heritage orientations (high decreasing and low increasing); for Turkish- and Moroccan-origin adolescents, three trajectories differed in mainstream orientations (high stable, low increasing, and high decreasing). Acculturative change affected aspects of later school adjustment: European-origin adolescents in high heritage orientation trajectories reported more belonging and emotional engagement; Turkish- and Moroccan-origin adolescents in high mainstream orientation trajectories reported more behavioral engagement.  相似文献   

6.
7.
The aim of this research is to characterize the development of fatigue damage by means of stress-strain hysteresis. Experiments were conducted on 14 specimens made of cold-finished unannealed AISI 1018 steel. Results demonstrate that the mechanical hysteresis loop areas, when plotted as a function of the number of loading cycles, show significant variations and demonstrate the three principal stages concerning the progress of the fatigue failure--initial accommodation, accretion of damage and terminal failure. These three stages of fatigue are marked by the transitions at cycles N2 and N3. Experimental results show that although fatigue life Nf ranges from 2644 cycles to 108 992 cycles, the ratios of N2/Nf and N3/Nf tend to be stable: N2/Nf=I 0.7%, N3/Nf=91.3%.  相似文献   

8.
Chemically processed Nb-doped SrTiO3 films and properties   总被引:1,自引:0,他引:1  
Homogeneous, crack-free SrNbxTi1−x O3 thin films on (110) silicon substrates were successfully fabricated by sol-gel processing. The optimum route and conditions were systematically investigated. Sr(OAc)2 glacial acctic acid solution, after being refluxed and reacted with tartrate, formed Sr(OAc)2(C4H6O6)2; Ti(OBu)4 formed Ti(OAc)4−x (AcAc)x after having the ligand partially exchanged with AcAc, while Nb(OC2H5)5 formed (OAc)2Nb(AcAc) (C4H6O6) by exchanging of ligand in glacial acetic acid with (CH3CO)2O. All the metal species after undergoing partial hydrolysis and polymerization with hydroxyl or oxygen, formed SrNbxTi1−x O13 cluster sol. Methyl cellulose (MCL) caused SrNbxTi1−x O3 sol to have polymeric structure and easily form films. SrNbxTi1−x O3 films with perovskite were subsequently formed after being annealed at 650∼750 °C for 60 min in 25% N2+75% H2 (volume ratio) atmosphere. Resistivity of the SrNb0.1Ti0.9O3 films at room temperature was 64 μω·cm, a particular T 2 temperature dependence of the resistivity, from 25 K up to room temperature, was observed. Project (No. 2002CB613305) supported by the National Basic Research Program (973) of China  相似文献   

9.
An efficient visible-light-responsive BiOBr/TiO2 heterojunction nanocomposite was fabricated successfully using in-situ depositing technique at room temperature by introducing BiOBr onto the surface of TiO2 nanobelts pre-prepared by hydrothermal reaction and etched with H2SO4. The obtained particles were characterized by XRD, SEM, TEM, XPS, UV-Vis DRS and PL techniques. BiOBr/TiO2 heterojunction nanocomposites with different mass ratios of m(BiOBr)/m(TiO2) were discussed in order to get the best photocatalytic activity, and BiOBr/TiO2-1.0 was proved to be the optimal mass ratio. BiOBr/TiO2-1.0 exhibited excellent photocatalytic activity in the degradation of RhB compared with TiO2 nanobelts, pure BiOBr and the mechanical mixture of TiO2 nanobelts and BiOBr. At last, a possible mechanism of photocatalytic enhancement was proposed.  相似文献   

10.
This study aimed to establish a closed-cycle operation technology with high thermal efficiency in the thermochemical sulfur-iodine cycle for large-scale hydrogen production. A series of experimental studies were performed to investigate the occurrence of side reactions in both the H2SO4 and HI x phases from the H2SO4/HI/I2/H2O quaternary system within a constant temperature range of 323–363 K. The effects of iodine content, water content and reaction temperature on the side reactions were evaluated. The results showed that an increase in the reaction temperature promoted the side reactions. However, they were prevented as the iodine or water content increased. The occurrence of side reactions was faster in kinetics and more intense in the H2SO4 phase than in the HI x phase. The sulfur or hydrogen sulfide formation reaction or the reverse Bunsen reaction was validated under certain conditions.  相似文献   

11.
The amorphous Fe67.5 alloy particles have been prepared by mechanical alloying(MA) process of elemental powders.The crystallization is observed at temperature around 405℃ by means of differential thermal analyzer,It is found that the coercivity Hc and the effective magnetic anisotropy value of amorphous phase are not far from that of crystal phase.The magnetization behavior of amorphous and nanocrystalline samples prepared by mechanical alloying and milling process are quite similar,they obey 1/H law at middle-high field and 1/H^2 at higher field.The 1/H field dependence is attributed to a large number of dislocations created during MA process.The studies on the 1/H^2 field dependence reveals that magnetization of Fe-Ni ultrafine particles are governed predominantly by internal stress fields induced by MA process.  相似文献   

12.
The current study took a person-centered approach to examine the heterogeneity of changes in children’s emotions and persistence during a goal-blocking task and examined how different profiles of emotions and persistence related to children’s self-regulation. Children’s anger, sadness, and persistence were rated in a goal-blocking task in toddlerhood (T1; N = 140, 72 boys, Mage = 2.67 years, 90.7% White) and preschool (T2). Children’s self-regulation, specifically sustained attention and engagement, was assessed at T1, T2, and early school-age (T3) from 2005 to 2012. Growth mixture modeling revealed two classes of children at T1 and three classes at T2 with different patterns of anger, sadness, and persistence. Children’s classification at T2, but not T1, significantly predicted their sustained attention and engagement both concurrently and longitudinally.  相似文献   

13.
Hydrogen dielectric-barrier discharge (H2-DBD) plasma was successfully used to prepare carbon nanotubes (CNTs)-supported cobalt (Co) catalyst. The H2-DBD plasma treatment simultaneously decomposed and reduced the cobalt precursor at a lower temperature and in a shorter time than the conventional method (calcination and hydrogen reduction). It is considered that the H2-DBD plasma method can remarkably decrease the amount of energy input compared to traditional methods used to prepare the Co-based catalyst in Fischer–Tropsch synthesis (FTS). Results showed that the Co catalyst prepared by H2-DBD plasma had an equivalent catalytic performance for FTS as that prepared using the conventional method in calcination and hydrogen reduction, thereby determining that H2-DBD plasma was an effective alternative treatment for preparing the Co/CNTs catalyst for FTS. This technology will provide a new strategy for preparing catalysts in other catalysis processes.  相似文献   

14.
Nanometer-sized SnO2 particles were prepared by a sol-gel method using inorganic salt as a precursor material. Its crystallization was investigated by means of TG-DTA, IR absorption spectra, X-ray diffractometry and TEM as well as its resistivity change and the gas sensitivity varied with temperature were measured in various reducing gas. The results indicate that well-crystallized nano-sized SnO2 with size around 15nm can be obtained at annealing temperature 600°C. The activation energy for the growth of nano-SnO2 was calculated to be 26. 55kJ. mol−1 when the annealing temperature was higher than 500°C. The measurements also show that there is a peculiar resistance change varied with temperature for nano-SnO2. It has relevance to the increase in surface adsorbed oxygen. The selective detectivities to C4H10 and petrol can be increased when ruthenium ion was doped in nano-SnO2 as a catalyst and so do the gas sensitivity to CO, CH4, H2 etc. when rhodium ion was doped in. The detection to the several reducing gas can be realized when the temperature ranged from 260°C to 400°C.  相似文献   

15.
The stabilizing conditions of W/O microemulsion of Tx-6-C4H9OH/c-C6h12/H2O system were studied by visual observation.The result shows that when the weight ratio of Tx-6 to C4H9OH is 4:1 ,the W/O microemulsion system has stabilizing and extensive regions,and the system is insensitive to the values of pH and in the range of room temperature.In accordance with the theoretical value of HLB,the suitable value of HLB for Tx-6 and C4H9OH to compose microemulsion is greater than 9,less than or equal to 10 value of HLB.the suitable value of HLB for Tx-6 and C4H9OH to compose microemulsion is greater than 9,less than or equal to 10.  相似文献   

16.
This study investigated trajectories of individual and vicarious online racial discrimination (ORD) and their associations with psychological outcomes for African American and Latinx adolescents in 6th–12th grade (N = 522; Mgrade = 9th) across three waves. Data were analyzed using growth mixture modeling to estimate trajectories for ORD and to determine the effects of each trajectory on Wave 3 depressive symptoms, anxiety, and self-esteem. Results showed four individual and three vicarious ORD trajectories, with the majority of participants starting out with low experiences and increasing over time. Older African American adolescents and people who spend more time online are at greatest risk for poor psychological functioning.  相似文献   

17.
In this study, the effects of ZrO_2 carrier precursors, MoO_3 loading, and washing treatment on the catalytic performance of Mo O_3/ZrO_2 toward sulfur-resistant methanation were investigated. All the catalysts were prepared by co-precipitation method and further characterized by N_2 adsorption–desorption, H_2-temperature-programmed reduction, X-ray diffraction, Raman spectroscopy and transmission electron microscopy. The prepared MoO_3/ZrO_2 catalysts were tested in a continuous-flow pressurized fixed bed reactor for CO methanation. The results revealed that the carrier precursors, MoO_3 loading, and washing treatment affected not only the crystalline phase of Mo species but also the grain size of ZrO_2 carrier and consequently influenced the MoO_3/ZrO_2 activity toward sulfur-resistant methanation. The 25 wt% MoO_3/ZrO_2 catalyst prepared using Zr(NO_3) 4 ·5 H_2O as the precursor and treated by water washing displayed the best activity for sulfur-resistant methanation due to its greater number of octahedral Mo species and smaller ZrO_2 grain size.  相似文献   

18.
With InCl3·4H2O being used as raw materials, the precursor of nano-sized In2O3 powder was prepared by hydrolysis, peptization and gelation of InCl3·4H2O. After calcination, nano-sized In2O3 powder was obtained. The powder was characterized by thermo-gravimetric and differential thermal analysis (TG-DTA), X-ray diffractometry (XRD) and transmission electron microscopy (TEM), respectively. Calculation revealed that the mean crystalline size increased with increasing the calcination temperature, but crystal lattice distortion rate decreased with the increasing in the average crystalline size. This indicated that the smaller the particle size, the bigger the crystal lattice distortion, the worse the crystal growing. The activation energies for growth of nano-sized In2O3 were calculated to be 4.75 kJ·mol−1 at the calcination temperature up to 500°C; and 66.40 kJ·mol−1 at the calcination temperature over 600°C. TEM photos revealed that the addition of the chemical additive (OP-10) greatly influenced the morphology and size of In2O3 particles.  相似文献   

19.
This study examined longitudinal effects of adolescent and parent cultural stress on adolescent and parent emotional well-being and health behaviors via trajectories of adolescent and parent family functioning. Recent immigrant Latino adolescents (Mage = 14.51) and parents (Mage = 41.09; N = 302) completed measures of these constructs. Latent growth modeling indicated that adolescent and parent family functioning remained stable over time. Early levels of family functioning predicted adolescent and parent outcomes. Baseline adolescent cultural stress predicted lower positive adolescent and parent family functioning. Latent class growth analyses produced a two-class solution for family functioning. Adolescents and parents in the low family functioning class reported low family functioning over time. Adolescents and parents in the high family functioning class experienced increases in family functioning.  相似文献   

20.
A. G. Samuelson  J. Jabadurai 《Resonance》2011,16(12):1152-1158
Dinitrogen (N2) is a very stable and inert molecule due to the formation of a triple bond between the two atoms. Surprisingly isoelectronic molecules are quite reactive making dinitrogen very useful and unique.  相似文献   

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