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71.
Longitudinal vortices disrupt the growth of the thermal boundary layer, thereby the vortex generators producing the longitudinal vortices are well known for the enhancement of heat transfer in compact heat exchangers. The present investigation determines the heat transfer characteristics with secondary flow analysis in plate fin triangular ducts with delta wing vortex generators. This geometrical configuration is investigated for various angles of attack of the wing i.e. 15°, 20°, 26° and 37° and Reynolds numbers 100 and 200. The constant wall temperature boundary condition is used. The solution of the complete Navier Stokes equation and the energy equation is carried out using the staggered grid arrangement. The performance of the combination of triangular secondary fins and delta wing with stamping on slant surfaces has also been studied. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
72.
We study a problem in stochastic functional differential equations which, in addition to a standard one-one-parameter noise term involves a random perturbation of the memory. This problem can also be regarded as a first order hyperbolic system of stochastic partial differential equations with given initial data and nonlocal boundary data. Existence and uniqueness of a solution is established and the generator of the associated Markov process is analyzed. Thereafter, for two model problems arising from first- and second-order integro-differential equations suggested by physical applications we establish asymptotic stability in probability of the associated stochastic processes. 相似文献
73.
Takeo Sasaki Takumi Yoneyama Shota Hashimoto Sumie Takemura Yumiko Naka 《Journal of polymer science. Part A, Polymer chemistry》2013,51(18):3873-3880
Photoinduced depolymerization of poly(olefin sulfone)s possessing photobase generators in the side‐chain was investigated. Irradiation with UV light generated base on the side‐chains and induced depolymerization based on proton abstraction on the main‐chain. The effect of the length of the spacer chain, which connects the photobase‐generating moiety to the polymer main chain on the photoinduced depolymerization, also was investigated. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 3873–3880 相似文献
74.
K Rama Mohana Rao 《Pramana》1990,35(2):141-149
A flow chart (inverted ‘tree’) for generating and identifying the 58 magnetic and 18 polychromatic point groups using a classification
for the 32 generating crystallographic point groups is suggested. The idea of colour generator is explored for generating
the colour symmetry point groups. The advantages in presenting the identification of colour groups through a tree are discussed. 相似文献
75.
Yasufumi Watanabe Ken‐ichi Fukukawa Yuji Shibasaki Mitsuru Ueda 《Journal of polymer science. Part A, Polymer chemistry》2005,43(3):593-599
A new negative‐working and alkaline‐developable photosensitive polyimide precursor based on poly(amic acid) (PAA), 4,4′‐methylenebis[2,6‐bis(hydroxymethyl)]phenol (MBHP) as a crosslinker, and a photoacid generator (5‐propylsulfonyloxyimino‐5H‐thiophen‐2‐ylidene)‐2‐(methylphenyl)acetonitrile (PTMA) has been developed. PAA was prepared by ring‐opening polymerization of pyromellitic dianhydride with 4,4′‐oxydianiline. The photosensitive polyimide precursor containing PAA (65 wt %), MBHP (25 wt %), and PTMA (10 wt %) showed a clear negative image featuring 10 μm line and space patterns when it was exposed to 436 nm light at 100 mJ·cm?2, post‐exposure baked at 130 °C for 3 min, followed by developing with a 2.38 wt % aqueous tetramethylammonium hydroxide solution at 25 °C. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 593–599, 2005 相似文献
76.
77.
在对定速风力发电机建模的基础上,设计了模型参考自适应控制器,并进行了跟随性能和抗干扰性能仿真,仿真结果表明自适应控制器的自适应能力很好. 相似文献
78.
79.
Meng-Dawn Cheng Leslie KarrJohn Kornuc David StaatThomas Wainman Bryan HarreBarbara Sugiyama 《Microchemical Journal》2002,72(2):209-219
High levels of lead in some occupational environments still exist. These include lead paint abatement sites, smelting operations, small arms firing ranges, and other construction scenarios. New emerging technologies provide the capability to provide an on-site alternative to conventional laboratory methods for airborne lead. In this paper we describe the evaluation of two such technologies using laboratory prepared lead-laden super-micron aerosol particles. Size measurements by TSI Aerodynamic Particle Sizer™ indicated the fluctuation of the peak particle sizes varying less than 1% among different runs for a given solution concentration. The content of lead embedded in the particles varied from 14 to 18% between runs of three different lead solution concentrations. A commercially available instrument for airborne lead measurement, AeroLead™, showed promise of becoming fully validated with the addition of design enhancements, although not fully validated by the end of the research program. Some of these areas being reworked by the manufacturer include working electrode issues, such as a more uniform surface area. Once these have been addressed, the manufacturer plans to complete the field and laboratory validation procedures. In a subsequent study, the ABF-LIPS results shown in this paper indicated that the technology could be used to quantify lead in aerosol form with a signal-to-noise ratio of three or larger of approximately 100 μg m−3 or higher quantity in a few minutes of measurement interval. The estimated detection limit for Pb using the ABF-LIPS prototype was approximately 60 μg m−3. In comparison the Resource Conservation and Recovery Act (RCRA) limit for Pb emission is 250 μg m−3. 相似文献
80.
徐瑞萍 《应用泛函分析学报》2006,8(4):341-343
主要讨论了自反Banach空间中一类C0-半群族{Th(t)}稳定性问题,证明了此类半群族{Th(t)}指数稳定与弱Lp-稳定是等价的. 相似文献