全文获取类型
收费全文 | 336篇 |
免费 | 2篇 |
国内免费 | 5篇 |
专业分类
化学 | 16篇 |
力学 | 42篇 |
数学 | 7篇 |
物理学 | 278篇 |
出版年
2022年 | 2篇 |
2021年 | 2篇 |
2020年 | 5篇 |
2019年 | 41篇 |
2018年 | 11篇 |
2017年 | 3篇 |
2016年 | 15篇 |
2015年 | 2篇 |
2014年 | 2篇 |
2013年 | 81篇 |
2012年 | 2篇 |
2011年 | 14篇 |
2010年 | 4篇 |
2009年 | 46篇 |
2008年 | 9篇 |
2007年 | 23篇 |
2006年 | 5篇 |
2005年 | 51篇 |
2004年 | 1篇 |
2003年 | 1篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 1篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1993年 | 2篇 |
1989年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1968年 | 2篇 |
排序方式: 共有343条查询结果,搜索用时 15 毫秒
11.
12.
A.S. Al-Shahrany D. Bradley M. Lawes R. Woolley 《Proceedings of the Combustion Institute》2005,30(1):225-232
A new technique is reported for measuring burning velocities at high pressures in the final stages of two inwardly propagating flame kernels in an explosion bomb. The flames were initiated at diametrically opposite spark electrodes, close to the wall, in quiescent mixtures. Measurements of pressure and flame kernel propagation speeds by high-speed photography showed the burning velocities to be elevated above the corresponding laminar burning velocities as a result of the developing flame instabilities. The enhancement increased with increase in pressure and decreased with increase in Markstein number. When the Markstein number was negative, instabilities could be appreciable, as could the enhancement. For the iso-octane–air mixtures investigated, where the mixtures had well-characterised Markstein numbers or critical Peclet numbers at the relevant pressures and temperatures, it was possible to explain the enhancement quantitatively by the spherical explosion flame instability theory of Bechtold and Matalon, provided the critical Peclet number was that observed experimentally, and allowance was made for the changing pressure. With this theoretical procedure, it was possible to derive values of laminar burning velocity from the measured values of burning velocity over a wide range of equivalence ratios, pressures, and temperatures. The values became less reliable at the higher temperatures and pressures as the data on Markstein and critical Peclet numbers became less certain. It was found that with iso-octane as the fuel the laminar burning velocity decreased during isentropic compression. 相似文献
13.
实验研究了内径分别为1 mm、2 mm和3 mm,水平通道长度为200 mm的Y形微燃烧器内氢气/空气扩散燃烧的火焰传播特性。首先,d=2 mm的燃烧器内的火焰传播模式最为丰富。其次,当燃烧器管径较大时,火焰更容易因扰动而发出噪音。在d=2和3 mm的燃烧器内能观察到两个阶段的噪音,而当d=1 mm时只有一个阶段的噪音。d=2 mm的燃烧器内平均火焰传播速度最小。而且,随着管径的增大,边界火焰更长。值得注意的是,在d=1 mm的燃烧器内,实验观察到了移动的"火焰街"。最后,基于系统的实验观察绘制了八种火焰传播模式的分布图。总之,本文不仅揭示了火焰传播特性与运行参数和尺度效应之间的关系,而且能为Y形微燃烧器的设计和运行提供指导。 相似文献
14.
Daniel Michelson 《Journal of Dynamics and Differential Equations》1993,5(3):375-415
Steadily rotating solutions of the Kuramoto-Sivashinsky equationu
t
+
2
u++¦u¦
2
=c
2
are studied. These solutions bifurcate from the steady radial solution of the above equation. For large values ofc and angular velocities such thatN¦¦<2c<(N+1)¦¦, we show that there exists a 2N-1 family of bifurcating solutions. The proof is based on a certain generic transversality assumption. A computer-assisted proof of this assumption is given for 1N10. 相似文献
15.
16.
17.
P. Anselmo-Filho S. Hochgreb R.S. Barlow R.S. Cant 《Proceedings of the Combustion Institute》2009,32(2):1763-1770
Combustion under stratified conditions is common in many systems. However, relatively little is known about the structure and dynamics of turbulent stratified flames. Two-dimensional imaging diagnostics are applied to premixed and stratified V-flames at a mean equivalence ratio of 0.77, and low turbulent intensity, within the corrugated flame range. The present results show that stratification affects the mean turbulent flame speed, structure and geometric properties. Stratification increases the flame surface density above the premixed flame levels in all cases, with a maximum reached at intermediate levels of stratification. The flame surface density (FSD) of stratified flames is higher than that of premixed flames at the same mean equivalence ratio. Under the present conditions, the FSD peaks at a stratification ratio around 3.0. The FSD curves for stratified flames are further skewed towards the product side. The distribution of flame curvature in stratified flames is broader and more symmetric relative to premixed flames, indicating an additional mechanism of curvature generation, which is not necessarily due to cusping. These experiments indicate that flame stratification affects the intrinsic behaviour of turbulent flames and suggest that models may need to be revised in the light of the current evidence. 相似文献
18.
Level-set G-equation and stationary flamelet chemistry are used in large eddy simulation of a propane/air premixed turbulent flame stabilized by a bluff body. The aim was to study the interaction between the flame front and turbulent eddies, and in particular to examine the effect of sub-grid scale (SGS) eddies on the wrinkling of the flame surface. The results indicated that the two types of turbulence eddies—the resolved large scale eddies and the unresolved SGS eddies—have different effects on the flame. The fluctuation of the flame surface, which is responsible for the broadening of the time averaged mean flame brush by turbulence, depends on the large resolved turbulence eddies. Time averaged mean flow velocity, temperature, and major species concentrations mainly depend on the large scale resolved eddies. The unresolved SGS eddies contribute to the wrinkling at the SGS level and play an important role in the enhancement of the propagation speed of the resolved flame front. In addition, the spatially filtered intermediate species, such as radicals, and the spatially filtered reaction rates strongly depend on the small SGS eddies. The asymptotic behavior of flame wrinkling by the SGS eddies, with respect to the decrease in filter size and grid size, is investigated further using a simplified level-set equation in a model shear flow. It is shown that to minimize the influence of the SGS eddies, fine grid and filter size may have to be used. 相似文献
19.
Mesoscale flame propagation and extinction of premixed flames in channels are investigated theoretically and experimentally. Emphasis is placed on the effect of wall heat loss and the wall–flame interaction via heat recirculation. At first, an analytical solution of flame speed in mesoscale channels is obtained. The results showed that channel width, flow velocity, and wall thermal properties have dramatic effects on the flame propagation and lead to multiple flame regimes and extinction limits. With the decrease in channel width, there exist two distinct flame regimes, a fast burning regime and a slow burning regime. The existence of the new flame regime and its extended flammability limit render the classical quenching diameter inapplicable. Furthermore, the results showed that at optimum conditions of flow velocity and wall thermal properties, mesoscale flames can propagate faster than the adiabatic flame. Second, numerical simulation with detailed chemistry demonstrated the existence of multiple flame regimes. The results also showed that there is a non-linear dependence of the flame speed on equivalence ratio. Moreover, it is shown that the Nusselt number has a significant impact on this non-linear dependence. Finally, the non-linear dependence of flame speed on equivalence ratio for both flame regimes is measured using a C3H8–air mixture. The results are in good agreement with the theory and numerical simulation. 相似文献
20.
Numerical simulation results are presented for three turbulent jet diffusion flames, stabilized behind a bluff body (Sydney
Flames HM1-3). Interaction between turbulence and combustion is modeled with the transported joint-scalar PDF approach. The
focus of the study is on the impact of the quality of simulation results in physical space on the behavior of two micro-mixing
models in composition space: the Euclidean Minimum Spanning Tree (‘EMST’) model and the modified Curl coalescence dispersion
(‘CD’) model. Profiles of conditional means and variances of thermo-chemical quantities, conditioned on the mixture fraction,
are discussed in the recirculation region and in the neck zone behind. The impact of the flow and mixing fields in physical
space on the mixing model behavior in composition space is strong for the CD model and increases as the turbulence – chemistry
interaction becomes stronger. The EMST conditional profiles, on the contrary, are hardly affected. 相似文献