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861.
In this paper, the hinged road-mat construction is modeled as a cable structure, and based on the equivalent cable theory the sinkage of the roadway is evaluated. Neglecting details of the interaction between tires and road mats, works caused by the traction, resistance, and drawbar pulling are defined to build a new work criterion to evaluate the mobility of vehicles on the hinged road mats. Mobility diagrams, related to coefficient of adhesion, terrain deformation, beam width, and fastening force, are developed to evaluate the locomotion of vehicles and further guide the design of hinged road mats. The presented method compares well with the field terramechanical experiments of the hinged road mats, thus verifying the validity of equivalent cable modeling and work criterion for hinged road mats. 相似文献
862.
Guowei Wang Bin Hu Xiaoshan Fan Yannan Zhang Junlian Huang 《Journal of polymer science. Part A, Polymer chemistry》2012,50(11):2227-2235
The tadpole‐shaped copolymers polystyrene (PS)‐b‐[cyclic poly(ethylene oxide) (PEO)] [PS‐b‐(c‐PEO)] contained linear tail chains of PS and cyclic head chains of PEO were synthesized by combination of Glaser coupling with living anionic polymerization (LAP) and ring‐opening polymerization (ROP). First, the functionalized polystyrene‐glycerol (PS‐Gly) with two active hydroxyl groups at ω end was synthesized by LAP of St and the subsequent capping with 1‐ethoxyethyl glycidyl ether and then deprotection of protected hydroxyl group in acid condition. Then, using PS‐Gly as macroinitiator, the ROP of EO was performed using diphenylmethylpotassium as cocatalyst for AB2 star‐shaped copolymers PS‐b‐(PEO‐OH)2, and the alkyne group was introduced onto PEO arm end for PS‐b‐(PEO‐Alkyne)2. Finally, the intramolecular cyclization was performed by Glaser coupling reaction in pyridine/Cu(I)Br/N,N,N′,N″,N″‐pentamethyldiethylenetriamine system under room temperature, and tadpole‐shaped PS‐b‐(c‐PEO) was formed. The target copolymers and their intermediates were well characterized by size‐exclusion chromatography, proton nuclear magnetic resonance spectroscopy, and fourier transform infrared spectroscopy in details. The thermal properties was also determined and compared to investigate the influence of architecture on properties. The results showed that tadpole‐shaped copolymers had lower Tm, Tc, and Xc than that of their precursors of AB2 star‐shaped copolymers. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
863.
MingHao Zhao WeiLing Zheng CuiYing Fan 《International Journal of Solids and Structures》2010,47(18-19):2525-2532
Based on the von Kármán plate theory, the mechanics of a shaft-loaded blister test for thin film/substrate systems is studied by considering elastic substrate deformations and residual stresses in these films. In testing, films are attached to a substrate provided with a circular hole, through which loading is applied to the film by a flat-ended shaft of circular cross-section. The effect of substrate deformation on the deflection of the loaded film is taken into account by using a line spring model. For small deflections, an analytical solution is derived, while for large deflections a numerical solution is obtained using the shooting method. The resulting load-shaft displacement relation, which is essential in blister tests, compares favorably with finite element analysis. 相似文献
864.
865.
Continuous flow infrared matrix‐assisted laser desorption electrospray ionization (CF IR MALDESI) mass spectrometry was demonstrated for the on‐line analysis of liquid samples. Samples in aqueous solution were flowed through a 50 µm i.d. fused‐silica capillary at a flow rate of 1–6 µL/min. As analyte aqueous solution flowed through the capillary, a liquid sample bead formed at the capillary tip. A pulsed infrared optical parametric oscillator (OPO) laser with wavelength of 2.94 µm and a 20 Hz repetition rate was focused onto the capillary tip for sample desorption and ablation. The plume of ejected sample was entrained in an electrospray to form ions by MALDESI. The resulting ions were sampled into an ion trap mass spectrometer for analysis. Using CF IR MALDESI, several chemical and biochemical reactions were monitored on‐line: the chelation of 1,10‐phenanthroline with iron(II), insulin denaturation with 1,4‐dithiothreitol, and tryptic digestion of cytochrome c. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
866.
Liang Hu Fan Yang Chaocan Zhang Yuanyuan Hu Yanjun Chen 《Colloid and polymer science》2011,289(3):323-331
In this work, a functional gradient polymeric material derived from silicon-containing acrylate blend emulsion film is prepared
in two steps. Firstly, 3-[tris(trimethylsilyloxy)silyl] propyl methacrylate (TRIS)-modified acrylate latex is prepared using
multiple emulsifiers by the two-stage semicontinuous emulsion copolymerization method. Next, blend latexes composed of TRIS-containing
and TRIS-free acrylate latexes are obtained. Detailed studies on the effects of the film-formation temperature and the glass
transition temperature (T
g) differences on the compositional gradient film are conducted. Surface energy analysis shows that silicon elements enriched
at the film-air (F-A) interface and T
g differences facilitate the fabrication of silicon gradient in emulsion blend films. Scanning electron microscopy-energy dispersive
X-ray further reveals that the concentration of silicon components varies in a gradient-like manner along the overall transaction
of the film when the film-formation temperature is 55 °C. However, excessive temperature creates the formation of a segmental
gradient distribution of silicon in the emulsion blend films. 相似文献
867.
We consider a Cauchy problem for the modified Helmholtz equation. A conditional stability estimate is proved. Two order optimal regularization methods and error estimates are investigated. Numerical experiment shows that these methods work well. 相似文献
868.
869.
Guowei Wang Xiaoshan Fan Junlian Huang 《Journal of polymer science. Part A, Polymer chemistry》2010,48(23):5313-5321
4μ‐A2B2 star‐shaped copolymers contained polystyrene (PS), poly(isoprene) (PI), poly(ethylene oxide) (PEO) or poly(ε‐caprolactone) (PCL) arms were synthesized by a combination of Glaser coupling with living anionic polymerization (LAP) and ring‐opening polymerization (ROP). Firstly, the functionalized PS or PI with an alkyne group and a protected hydroxyl group at the same end were synthesized by LAP and then modified by propargyl bromide. Subsequently, the macro‐initiator PS or PI with two active hydroxyl groups at the junction point were synthesized by Glaser coupling in the presence of pyridine/CuBr/N,N,N ′,N ″,N ″‐penta‐methyl diethylenetri‐amine (PMDETA) system and followed by hydrolysis of protected hydroxyl groups. Finally, the ROP of EO and ε‐CL monomers was carried out using diphenylmethyl potassium (DPMK) and tin(II)‐bis(2‐ethylhexanoate) (Sn(Oct)2) as catalyst for target star‐shaped copolymers, respectively. These copolymers and their intermediates were well characterized by SEC, 1H NMR, MALDI‐TOF mass spectra and FT‐IR in details. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010 相似文献
870.
Dongping Zhang Ping Fan Congjuan Wang Xingmin Cai Guangxing Liang Jianda Shao Zhengxiu Fan 《Optics & Laser Technology》2009,41(6):820-822
HfO2 thin films were prepared in dual-ion-beam reactive sputtering (DIBRS) method. Spectrophotometer, surface thermal lensing (STL) technique, Rutherford backscattering (RBS), and X-ray diffraction (XRD) were employed in measuring the transmittance, absorptance, stoichiometry, and microstructure, respectively. Experimental results indicate that the peak transmittance value of the sample is about 90%. Weak absorptance measurement for 1064 nm wavelength laser by STL technique investigated that the absorption is 180 ppm for as-grown sample, which is larger than expected. Substoichiometry is the main cause for larger absorptance, which could be proved by RBS and annealing test results. XRD result shows that the films are polycrystalline, and the monoclinic is the dominant phase. 相似文献