全文获取类型
收费全文 | 60篇 |
免费 | 0篇 |
专业分类
化学 | 32篇 |
晶体学 | 5篇 |
力学 | 1篇 |
数学 | 1篇 |
物理学 | 21篇 |
出版年
2023年 | 1篇 |
2020年 | 1篇 |
2016年 | 2篇 |
2015年 | 1篇 |
2013年 | 2篇 |
2012年 | 1篇 |
2011年 | 1篇 |
2008年 | 2篇 |
2007年 | 5篇 |
2006年 | 1篇 |
2005年 | 1篇 |
2004年 | 3篇 |
2003年 | 1篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1998年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1983年 | 2篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1974年 | 2篇 |
1973年 | 1篇 |
排序方式: 共有60条查询结果,搜索用时 15 毫秒
31.
R.B. Greegor K.Y. Blohowiak J.H. Osborne K.A. Krienke J.T. Cherian F.W. Lytle 《Journal of Sol-Gel Science and Technology》2001,20(1):35-50
X-ray photoelectron spectroscopy (XPS) and x-ray absorption spectroscopy (XAS) measurements were made on thin film (1000 Å) sol-gel adhesion promoting surface treatments. These silicon/zirconium-containing sol-gel coatings are possible replacement processes for traditional surface preparations that use environmentally undesirable and potentially toxic materials. The sol-gels were waterborne mixtures formulated with tetra-n-propoxyzirconium (TPOZ) and a silane, either 3-glycidoxypropyl-trimethoxysilane (GTMS) or 3-aminopropyl-triethoxysilane (APS). Results show that dried sol-gel powders formulated with TPOZ or TPOZ + GTMS have longer Zr—O bond lengths (2.18 Å, CN 7 or 8) than the TPOZ + silane + metal substrate samples (2.10 Å, CN 6). The fraction (+/– 0.10) of Zr in a short bonded 6-fold site is highest (0.80) for TPOZ + (APS or GTMS) on (Ti or Al), at an intermediate value (0.40) for TPOZ on Ti and low (0.10) for the powders. For sol-gels deposited on a metal substrate, there are indications of a chemical bond between the thin film sol-gel and the metal substrate. The TPOZ + APS coatings on Ti data suggest that this Zr—O—Ti bond is present with a Zr—Ti separation of 3.5 Å. Only subtle differences were observed in the near-neighbor bonding due to curing treatment variations from room temperature to 125°C, alloy substrate variations (Ti-6Al-4V/Al 2024), and age of the deposited sol-gel coating (up to 1 year). 相似文献
32.
G. Rhoderick Pamela Chu Eric Dolin Jerry Marks Touche Howard Mark Lytle L. McKenzie Don Altman 《Analytical and bioanalytical chemistry》2001,370(7):828-833
An EPA Voluntary Aluminum Industrial Partnership (VAIP) program has been formed to help US primary producers focus on reducing
the emissions of two perfluorocarbons (PFCs), tetrafluoromethane (CF4) and hexafluoroethane (C2F6), during the production of aluminum. To ensure comparability of measurements over space and time, traceability to national
sources was desirable. Hence, the EPA approached the NIST to develop a suite of primary standards to cover a mole fraction
(concentration) range of 0.1 to 1400 μmol mol–1 for CF4 and 0.01 to 150 μmol mol–1 of C2F6. A total of eight gravimetric PFC gas standards were prepared with relative expanded uncertainties of ≤ 0.52% (≈95% confidence
level). These primary standards were ultimately used to assign values to a series of secondary gas standards at three mole-fraction
levels with relative expanded uncertainties ranging from ± 0.7% to 5.3% (≈95% confidence level). This series of secondary
standards was used within the aluminum industry to calibrate instruments used to make emission measurements. Assignment of
values to the secondary standards was performed by use of gas chromatography with flame-ionization detection (GC–FID) and
Fourier transform infrared spectrometry (FTIR). Real time pot-line and stack samples from a local aluminum plant were also
obtained and sub-samples sent to each participating facility for analysis. The data generated from each facility were sent
to NIST for analysis. The maximum difference between the NIST and individual facilities’ values for the same sub-sample was
± 26%.
Received: 19 January 2001 / Revised: 27 March 2001 / Accepted: 6 April 2001 相似文献
33.
Lytle AL Zhang X Peatross J Murnane MM Kapteyn HC Cohen O 《Physical review letters》2007,98(12):123904
We use counterpropagating light to directly observe the coherent buildup of high harmonic generation in a hollow waveguide geometry. We measure, for the first time, coherence lengths for high photon energies that cannot be phase matched using conventional approaches. We also probe the transition through phase matching, the ionization level at which different harmonic orders are generated, and the change in the coherence length as the driving laser is depleted. These results directly prescribe the optimal structures or pulse trains required for implementing quasiphase matching. 相似文献
34.
Christian J. Breckner Dr. Hien N. Pham Michael G. Dempsey Michelle A. Perez-Ahuatl Alyssa C. Kohl Corryn N. Lytle Prof. Abhaya K. Datye Prof. Jeffrey T. Miller 《Chemphyschem》2023,24(14):e202300244
Olefin oligomerization by γ-Al2O3 has recently been reported, and it was suggested that Lewis acid sites are catalytic. The goal of this study is to determine the number of active sites per gram of alumina to confirm that Lewis acid sites are indeed catalytic. Addition of an inorganic Sr oxide base resulted in a linear decrease in the propylene oligomerization conversion at loadings up to 0.3 wt %; while, there is a >95 % loss in conversion above 1 wt % Sr. Additionally, there was a linear decrease in the intensity of the Lewis acid peaks of absorbed pyridine in the IR spectra with an increase in Sr loading, which correlates with the loss in propylene conversion, suggesting that Lewis acid sites are catalytic. Characterization of the Sr structure by XAS and STEM indicates that single Sr2+ ions are bound to the γ-Al2O3 surface and poison one catalytic site per Sr ion. The maximum loading needed to poison all catalytic sites, assuming uniform surface coverage, was ∼0.4 wt % Sr, giving an acid site density of ∼0.2 sites per nm2 of γ-Al2O3, or approximately 3 % of the alumina surface. 相似文献
35.
Using a model developed for estimating solar inactivation of viruses of biodefense concerns, we calculated the expected inactivation of SARS-CoV-2 virus, cause of COVID-19 pandemic, by artificial UVC and by solar ultraviolet radiation in several cities of the world during different times of the year. The UV sensitivity estimated here for SARS-CoV-2 is compared with those reported for other ssRNA viruses, including influenza A virus. The results indicate that SARS-CoV-2 aerosolized from infected patients and deposited on surfaces could remain infectious outdoors for considerable time during the winter in many temperate-zone cities, with continued risk for re-aerosolization and human infection. Conversely, the presented data indicate that SARS-CoV-2 should be inactivated relatively fast (faster than influenza A) during summer in many populous cities of the world, indicating that sunlight should have a role in the occurrence, spread rate and duration of coronavirus pandemics. 相似文献
36.
Farrel Lytle 《Synchrotron Radiation News》2015,28(4):30-33
The study of X-ray absorption spectroscopy (XAS) began at an exciting time in science. In the early years of the twentieth century, wave mechanics, X-ray diffraction, X-ray scattering from non-crystalline materials, electron diffraction, and XAS were all being developed simultaneously. Many XAS concepts and experimental techniques advanced in parallel with these other subjects; however, the difficulty of obtaining good XAS data from conventional X-ray tubes limited the field to a potentially interesting minor subject [1, 2]. 相似文献
37.
Excited state rate constants have been obtained for complexes of rhodamine B and tetrachloroanions of the group IIIA metals. The results were analyzed by comparison with a heavy atom effect model. Other interaction mechanisms were discussed as well as the suitability of this system for time resolved fluorescence analysis. 相似文献
38.
Acetophenone is found to exhibit no prompt fluorescence at the 10?6 quantum yield level when purified by fractional distillation and a double GC preparation. The emission observed is primarily room temperature, solution phosphorescence and the solvent blank. A classical analysis of 77 K phosphorescence data supports and n→π1 triplet assignment with polar solvents and a π→π1 assignment with very non-polar solvents. 相似文献
39.
Blum T Boyle PA Christ NH Garron N Goode E Izubuchi T Jung C Kelly C Lehner C Lightman M Liu Q Lytle AT Mawhinney RD Sachrajda CT Soni A Sturm C;RBC UKQCD Collaborations 《Physical review letters》2012,108(14):141601
We report on the first realistic ab initio calculation of a hadronic weak decay, that of the amplitude A(2) for a kaon to decay into two π mesons with isospin 2. We find ReA(2)=(1.436±0.063(stat)±0.258(syst))10(-8) GeV in good agreement with the experimental result and for the hitherto unknown imaginary part we find ImA(2)=-(6.83±0.51(stat)±1.30(syst))10(-13) GeV. Moreover combining our result for ImA(2) with experimental values of ReA(2), ReA(0), and ε'/ε, we obtain the following value for the unknown ratio ImA(0)/ReA(0) within the standard model: ImA(0)/ReA(0)=-1.63(19)(stat)(20(syst)×10(-4). One consequence of these results is that the contribution from ImA(2) to the direct CP violation parameter ε' (the so-called Electroweak Penguin contribution) is Re(ε'/ε)(EWP)=-(6.52±0.49(stat)±1.24(syst))×10(-4). We explain why this calculation of A(2) represents a major milestone for lattice QCD and discuss the exciting prospects for a full quantitative understanding of CP violation in kaon decays. 相似文献
40.
L. E. Bockstahler R. K. Elespuru V. M. Hitchins P. G. Carney K. M. Olvey C. D. Lytle 《Photochemistry and photobiology》1990,51(4):477-479
The capacity of human fibroblasts to support plaque formation by Herpes simplex virus following treatment of the cells with gilvocarcin V, a polyaromatic C-glycoside, plus near ultraviolet radiation (UVA, 320-400 nm) was examined. Gilvocarcin V, plus UVA radiation, effectively inhibited host cell capacity at concentrations five orders of magnitude lower than that of 8-methyoxypsoralen required for capacity inhibition at similar levels of UVA radiation. This result extends the observation of unusual biological potency of UVA-activated gilvocarcins from bacterial cells to human cells. 相似文献