全文获取类型
收费全文 | 208篇 |
免费 | 2篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 42篇 |
金属工艺 | 6篇 |
机械仪表 | 3篇 |
矿业工程 | 1篇 |
能源动力 | 11篇 |
轻工业 | 6篇 |
水利工程 | 1篇 |
无线电 | 6篇 |
一般工业技术 | 79篇 |
冶金工业 | 46篇 |
原子能技术 | 6篇 |
自动化技术 | 1篇 |
出版年
2022年 | 1篇 |
2021年 | 5篇 |
2020年 | 2篇 |
2018年 | 1篇 |
2017年 | 5篇 |
2016年 | 2篇 |
2015年 | 3篇 |
2014年 | 8篇 |
2013年 | 12篇 |
2012年 | 2篇 |
2011年 | 10篇 |
2010年 | 13篇 |
2009年 | 1篇 |
2008年 | 10篇 |
2007年 | 10篇 |
2006年 | 4篇 |
2005年 | 9篇 |
2004年 | 12篇 |
2003年 | 6篇 |
2002年 | 5篇 |
2001年 | 3篇 |
2000年 | 7篇 |
1999年 | 4篇 |
1998年 | 25篇 |
1997年 | 10篇 |
1996年 | 5篇 |
1995年 | 7篇 |
1994年 | 7篇 |
1993年 | 7篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1982年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有210条查询结果,搜索用时 250 毫秒
201.
Dynamics of interactive quantized vortices in rotating superfluid is studied theoretically. This work considers the basic system where superfluid is contained in a cylindrical vessel that rotates about its axis at an angular velocity. Although two-dimensional equilibrium patterns of vortex arrays are understood fairly well at present, there has been only a little amount of information on the dynamical aspects. Thus this work studies some typical dynamical problems, i.e., formation of vortex array and spin-down process. We describe also three-dimensional analysis which is much more troublesome than two-dimensional one. 相似文献
202.
BACKGROUND: The study sought to determine dynamic changes and theoretical bases of a clinical diagnostic test, the tear clearance rate. METHODS: Thirty four healthy subjects ranging in age from 22 to 84 years underwent examination of tear clearance rate, the Schirmer test with anaesthesia, as well as fluorophotometric measurement of tear turnover, tear volume, and tear flow. By applying 0.5% fluorescein into the conjunctival sac and subsequently measuring colour fades on a Schirmer strip, the tear clearance rate for assessing tear drainage was divided into nine grades. The results of the tear clearance rate were compared with those of the basal tear turnover and tear flow obtained from fluorophotometry. RESULTS: Significant relations were found between the tear clearance rate and the basal tear turnover or tear flow (r = 0.91 and 0.79, respectively, p = 0.0001). Considering the grades of progression from low to high, each grade of tear clearance rate showed a 12.5% increase in basal tear turnover (3.59%/min) and tear flow (0.38 microliter/min). There was no significant correlation between age and the basal tear turnover, tear volume, tear flow, or the tear clearance rate. CONCLUSION: The tear clearance rate is proposed as a simple and useful way to estimate basal tear turnover and tear flow, and measure tear drainage indirectly. 相似文献
203.
Shoji Fujiyama Risto Hänninen Makoto Tsubota 《Journal of Low Temperature Physics》2007,148(3-4):263-267
We report here the results of a computer simulation of quantized vortex pinning in He II at 0 K in the simple situation where
a single sphere and a rectilinear vortex are considered. Our simulation shows that a vortex nearby a sphere is captured due
to a velocity field produced by the sphere, exciting Kelvin waves. The dependence of the “pinning” on temperature is investigated
as well. Finally, the possibility of pinning in PIV experiments, which visualize superfluid turbulence, is discussed. 相似文献
204.
A boojum is a topological defect that can form only on the surface of an ordered medium such as superfluid 3He and liquid crystals. By analogy with superfluid 3He, we numerically create boojums between two phases with different vortex structures in two-component BECs where the intercomponent
interaction is spatially dependent. The detailed structure of the boojums is revealed by investigating its density distribution,
effective superflow vorticity and pseudospin texture. 相似文献
205.
We have simulated the decay of thermal counterflow quantum turbulence from a statistically steady state at T=1.9 K, with the assumption that the normal fluid is at rest during the decay. The results are consistent with the predictions of the Vinen equation (in essence the vortex line density decays as t ?1). For the statistically steady state, we determine the parameter c 2, which connects the curvature of the vortex lines and the mean separation of vortices. A formula connecting the parameter χ 2 of the Vinen equation with c 2 is shown to agree with the results of the simulations. Disagreement with experiment is discussed briefly. 相似文献
206.
Hiromitsu Takeuchi Kenichi Kasamatsu Makoto Tsubota Muneto Nitta 《Journal of Low Temperature Physics》2013,171(3-4):443-454
In brane cosmology, the Big Bang is hypothesized to occur by the annihilation of the brane–anti-brane pair in a collision, where the branes are three-dimensional objects in a higher-dimensional Universe. Spontaneous symmetry breaking accompanied by the formation of lower-dimensional topological defects, e.g. cosmic strings, is triggered by the so-called ‘tachyon condensation’, where the existence of tachyons is attributable to the instability of the brane–anti-brane system. Here, we discuss the closest analogue of the tachyon condensation in atomic Bose–Einstein condensates. We consider annihilation of domain walls, namely branes, in strongly segregated two-component condensates, where one component is sandwiched by two domains of the other component. In this system, the process of the brane annihilation can be projected effectively as ferromagnetic ordering dynamics onto a two-dimensional space. Based on this correspondence, three-dimensional formation of vortices from a domain-wall annihilation is considered to be a kink formation due to spontaneous symmetry breaking in the two-dimensional space. We also discuss a mechanism to create a ‘vorton’ when the sandwiched component has a vortex string bridged between the branes. We hope that this study motivates experimental researches to realize this exotic phenomenon of spontaneous symmetry breaking in superfluid systems. 相似文献
207.
Spherical activated carbon derived from spherical cellulose and its performance as EDLC electrode
下载免费PDF全文
![点击此处可从《应用聚合物科学杂志》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Spherical activated carbons (ca. 30–100 μm in diameter) were synthesized from commercial spherical cellulose beads. The addition of guanidine phosphate was performed as the pretreatment, and CO2 activation was applied for enhancing the specific surface area. The addition of guanidine phosphate drastically improved the yield of carbon during the activation process. The specific surface area reached 1545 m2 g?1 for the sample heat‐treated at 850°C for 1 h in flowing N2 and continuously for 3 h in flowing CO2 activation. The calculated capacitance values per area (F m?2) for the pore size of less than 1 nm was large in the case of small current density. The distortion of the solvation shell could be the reason for the large capacitance value for the small pore size of less than 1 nm. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40950. 相似文献
208.
We consider theoretically static and dynamic properties of multicomponent Bose–Einstein condensates (BECs) composed of a mixture
of 174Yb and 176Yb atoms. The condensate of 176Yb atoms has an attractive interaction, collapsing above a certain critical particle number. This criterion is modified by
the presence of another repulsive condensate of 174Yb atoms. We discuss the stability condition of this condensate mixture and collapsing dynamics due to the instability.
相似文献
209.
Zhaoxia Song Naoki Mimura Susumu Tsubota Tadahiro Fujitani S. Ted Oyama 《Catalysis Letters》2008,121(1-2):33-38
The gas-phase epoxidation of propylene was studied over MoO
x
/SiO2 catalysts in a reaction system with a post-catalytic bed volume. In the reaction of a mixture of propylene and propane with
oxygen below 578 K, propylene oxide (PO) was mainly formed from the oxidation of propylene. It was found that the oxidation
reaction was very sensitive to the temperature of the post-catalytic space more than the temperature of the catalyst bed,
strongly indicating that radical reactions occurring in the post-catalytic bed free space were responsible for the PO formation.
The addition of NO increased propylene conversions and PO selectivity at low conversions, confirming that radical reactions
were involved in the propylene reactions. 相似文献
210.
Junya Miyahara Naoki Shirakawa Yuta Setoguchi Masami Tsubota Kento Kuroiwa Jiro Kitagawa 《Journal of Superconductivity and Novel Magnetism》2018,31(11):3559-3564
The Hill plot is a well-known criterion of the f-electron element interatomic threshold distance separating the nonmagnetic state from the magnetic state in actinides and lanthanides. We have reinvestigated the Hill plot of Ce compounds using the commercial crystallographic database CRYSTMET, focusing on a relationship between the Ce-Ce distance and the magnetic ordering temperature because a Ce compound with no other magnetic elements rarely has a magnetic ordering temperature that is higher than 20 K. The Hill plot of approximately 730 compounds has revealed that a Ce compound, particularly a ferromagnet, showing a high magnetic ordering temperature would require a short Ce-Ce distance with a suppression of the valence instability of the Ce ion. From the study, we developed interest in Ce2AuP3 with a Curie temperature of 31 K. The ferromagnetic nature of this material has been examined in terms of a doping effect, which suggests a possible increase in magnetic anisotropy energy. 相似文献