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排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
角接触球轴承是航天器的许多重要功能的实施部件,因而对其润滑性能的要求极为严格,迫切需要弄清其润滑失效机理。因此,对MoS2溅射膜润滑的C6205球轴承进行了寿命试验,进而对经过丙酮超声清洗的各元件工作面的形貌和组成作了系统分析。 相似文献
992.
In previous studies on plasma-particle interaction, as far as we know, the rf plasma flow and temperature fields are all simulated
by the non-self-consistent one-dimensional electromagnetic (1-D EM) field model. In the present paper, the complete self-consistent
two-dimensional electromagnetic (2-D EM) field model incorporating the axial Lorentz force component, which is neglected in
the 1-D model, is firstly adopted to calculate the aluminium particle trajectory and thermal history in atmospheric rf Ar
plasma with the particle evaporation effect included. The crucial effect of reverse flow within the coil region on the particle
trajectory is discovered and the results show that the 2-D EM field model must be adopted instead of the 1-D model when the
plasma-particle interaction is studied. The effect of carrier gas flux on the particle movement and heating are also studied,
resulting in some useful conclusions for both plasma theory and application.
recommended by Prof. Wu Chengkang
The project supported by the National Natural Science Foundation of China 相似文献
993.
Jodie N. Haigh Ya‐mi Chuang Brooke Farrugia Richard Hoogenboom Paul D. Dalton Tim R. Dargaville 《Macromolecular rapid communications》2016,37(1):93-99
A new method for fabricating hydrogels with intricate control over hierarchical 3D porosity using microfiber porogens is presented. Melt electrospinning writing of poly(ε‐caprolactone) is used to create the sacrificial template leading to hierarchical structuring consisting of pores inside the denser poly(2‐oxazoline) hydrogel mesh. This versatile approach provides new opportunities to create well‐defined multilevel control over interconnected pores with diameters in the lower micrometer range inside hydrogels with potential applications as cell scaffolds with tunable diffusion and transport of, e.g., nutrients, growth factors or therapeutics.
994.
Matthias Conradi Gijs Ramakers Thomas Junkers 《Macromolecular rapid communications》2016,37(2):174-180
Benzaldehyde‐functional cellulose paper sheets have been synthesized via tosylation of cellulose (Whatman No 5) followed by addition of p‐hydroxy benzaldehyde. Via UV‐induced Paterno–Büchi [2+2] cycloaddition reactions, these aldehyde functional surfaces are grafted with triallylcyanurate, trimethylolpropane allyl ether, and vinyl chloroacetate. In the following, allyl‐functional polymers (poly(butyl acrylate), pBA, Mn = 6990 g mol−1, Đ = 1.12 and poly(N‐isopropyl acrylamide), pNIPAAm, Mn = 9500 g mol−1, Đ = 1.16) synthesized via reversible addition fragmentation chain transfer polymerization are conjugated to the celloluse surface in a UV‐induced grafting‐to approach. With pBA, hydrophobic cellulose sheets are obtained (water contact angle 116°), while grafting of pNIPAAm allows for generation of “smart” surfaces, which are hydrophilic at room temperature, but that become hydrophobic when heated above the characteristic lower critical solution temperature (93° contact angle). The Paterno–Büchi reaction has been shown to be a versatile synthetic tool that also performs well in grafting‐to approaches whereby its overall performance seems to be close to that of radical thiol‐ene reactions.
995.
利用一维扩展过程的奇点理论并结合能量包络的随机平均法,考查“隐藏在余维2分岔点之后”的同宿分岔系统受参激白噪声影响的分岔行为。 相似文献
996.
It has been proposed to rise Venice by injecting CO2 into an aquifer lying 600–800 m below its lagoon. It is shown that because of the prevailing ambient conditions in the aquifer phase change of CO2 cannot be avoided. The ensuing change of specific volume and compressibility will inhibit a uniform uplift pattern which is needed to avoid cracks in historical buildings. Further, both liquid and gaseous CO2 produce capillary effects at the contact surface with water in the voids of the reservoir rock and this affects its mechanical response. Hence further non homogeneity in the uplift pattern will be produced. This prevents the use of CO2 in the proposed conditions. 相似文献
997.
998.
Critical conditions for the direct initiation of self-sustained detonation in cryogenic hydrogen-oxygen mixtures are examined experimentally. These initial conditions are expected to depend mainly on four parameters: the equivalence ratio of the mixture, the amount of the initial energy deposition, the initial temperature and pressure of the mixture. These critical conditions are determined by fixing alternatively three of these parameters and varying the fourth one from subcritical to supercritical detonation conditions. Results are presented for initial pressuresP
o and equivalence ratios ranging from 0.3 to 1 bar and from 1 to 2 respectively, for the two initial temperaturesT
o, 123 K and 293 K. These results indicate that for the lowest values of the initial pressure, a decrease of initial temperature may favour the onset of detonation. Whatever the initial conditions, the measured detonation pressures and velocities are in reasonably good agreement with the corresponding Chapman-Jouguet values computed using the ideal-gas equation of state. 相似文献
999.
二维定常爆轰波的C-J条件与流线形状 总被引:2,自引:0,他引:2
本文在W-K模型的基础上,采用自然坐标系,导出了二维定常爆轰波的声速面条件,即二维C-J条件。经典的一维C-J条件和准一维C-J条件是它的两个特例。声速面条件又可作为判定流线形状正确与否的必要条件。通过分析讨论,认为在二维定常爆轰波的有效反应区中,流线应呈先向内,后向外偏转的波纹型形。在确定声速面形状的同时,有效反应区的流场分布也随之确定。 相似文献
1000.