全文获取类型
收费全文 | 70篇 |
免费 | 1篇 |
国内免费 | 9篇 |
专业分类
测绘学 | 1篇 |
大气科学 | 43篇 |
地球物理 | 16篇 |
地质学 | 4篇 |
海洋学 | 7篇 |
天文学 | 4篇 |
综合类 | 4篇 |
自然地理 | 1篇 |
出版年
2024年 | 1篇 |
2014年 | 1篇 |
2013年 | 2篇 |
2010年 | 2篇 |
2009年 | 5篇 |
2008年 | 1篇 |
2007年 | 4篇 |
2005年 | 7篇 |
2004年 | 3篇 |
2003年 | 5篇 |
2002年 | 4篇 |
2001年 | 5篇 |
2000年 | 4篇 |
1999年 | 4篇 |
1998年 | 4篇 |
1997年 | 8篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1985年 | 4篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1980年 | 1篇 |
1978年 | 2篇 |
排序方式: 共有80条查询结果,搜索用时 31 毫秒
51.
52.
53.
Y. N. Samsonov 《Journal of Atmospheric Chemistry》2007,56(2):127-147
A chemical substance being in a high-disperse state (fine aerosol particles and very thin films) in the environment reveals
specific chemical and physicochemical features which differ from the processes in a relatively coarse disperse object and,
even more, in ordinary liquid and solid “test-tube” assays. The kinetics and the mechanism of the direct and sensitized photochemical
destruction of pesticide compound fipronil C12H4Cl2F6N4OS have been experimented as applied to the aerosol particles ≈0.12–1.3 μm in diameter and thin films ≈0.02–0.6 μm thick on
the glass plates. A non-photochemical (“dark”) reaction of fipronil molecules with the OH radicals which spontaneously proceeds
in the ambient air was also observed. Quantitative estimations based on experimental results show that the fipronil pollutant,
observed in the atmosphere in the form of levitated aerosols, can convert chemically in the above reaction with the OH radicals
for a very short time (from several minutes for a particle 2 μm in diameter to 12–24 h for a particle of 20–30 μm). The fipronil
residues presented on foliage either in the form of 1–20 μm films or as a group of deposited 2–30 μm aerosols react under
sunlight by two photochemical pathways (photooxidation and photodecay). The lifetime of these residues in the ambient conditions
is expected to be 11–25 days. Besides, adding a small amount of the Shirvanol 2 sensitizer to the fipronil formulation, one
can increase the overall decomposition rate to 8–12 days. 相似文献
54.
G. Salisbury P. S. Monks S. Bauguitte B. J. Bandy S. A. Penkett 《Journal of Atmospheric Chemistry》2002,41(2):163-187
Measurements of the sum of peroxy radicals [HO2 + RO2],NOx (NO + NO2) and NOy (the sum of oxidisednitrogen species) made at Mace Head, on the Atlantic coast of Ireland in summer 1996 and spring 1997 are presented. Together with a suite of ancillary measurements, including the photolysis frequencies of O3 O(1D)(j(O1D)) and NO2 (j(NO2)), the measured peroxy radicals are used to calculate meandailyozone tendency (defined as the difference of the in-situphotochemical ozone production and loss rates); these values are compared with values derived from the photochemical stationary state (PSS) expression. Although the correlation between the two sets of values is good, the PSS values are found to be significantly larger than those derived from the peroxy radical measurements, on average, in line with previous published work. Possible sources of error in these calculations are discussed in detail. The data are further divided up into five wind sectors, according to the instantaneous wind direction measured at the research station. Calculation of mean ozone tendencies by wind sector shows that ozone productivity was higher during spring (April–May) 1997 than during summer (July–August) 1996across all airmasses, suggesting that tropospheric photochemistry plays an important role in the widely-reported spring ozone maximum in the Northern Hemisphere. Ozone tendencies were close to zero for the relatively unpolluted south-west, west and north-west wind sectors in the summer campaign, whereas ozone productivity was greatest in the polluted south-east sector for both campaigns. Daytime weighted average ozone tendencies were +(0.3± 0.1) ppbv h–1 for summer 1996 and +(1.0± 0.5) ppbvh–1 for spring 1997. These figures reflect the higher mixing ratios of ozone precursors in spring overall, as well as the higher proportion of polluted air masses from the south-east arriving at the site during the spring campaign. The ozone compensation point, where photochemical ozone destruction and production processes are in balance, is calculated to be ca. 14 pptv NO for both campaigns. 相似文献
55.
56.
The Fe(II)/Fe(III)-partition in cloudwater samples collected during two field campaigns is evaluated. It turned out that the simultaneous occurrence of complexing and reducing substances in the atmosphere and the cloud processing increase the solubility of iron compounds present in aerosol particles. A correlation between the concentration of iron(II) in the liquid phase and the intensity of the solar irradiation was observed for most of the cloudwater samples. This could be due to the fact that both the photochemical reduction of the iron(III) complexes and the photochemical reductive dissolution of iron(III)(hydr)oxides are depending on the pH-value. Iron(II) seems to be oxidised back to iron(III) preferably by hydrogen peroxide during the night. Positive correlations were received e.g. between the concentration of dissolved iron and the concentration of oxalate and between the percentage of iron(III) and the concentration of hydrogen peroxide. A negative correlation was found e.g. between the concentration of dissolved iron and the pH-value. The uncertainty of the whole process of sampling and analysis was investigated and the conformity of the results was satisfying considering the sometimes difficult conditions during a field campaign. 相似文献
57.
J. Quesada D. Grossmann E. Fernández J. Romero E. Sanhueza G. Moortgat P. J. Crutzen 《Journal of Atmospheric Chemistry》2001,39(1):15-36
As part of the LBA-CLAIRE-98 experiment, ground level atmosphericconcentrations of O3, CO, hydroperoxides and organic acids weremeasured in the rainforest region in Surinam. Measurements of CO andO3 were also made at a coastal site.The results suggest that a significant consumption of `boundary layer' ozoneoccurs over the forested region of Surinam, with an estimated net ozoneconsumption of about 5% hr–1 during daytime. Thiswould be mainly explained by a low photochemical production and high drydeposition to the forest vegetation. Compared to other tropical sites, lowerlevels of H2O2 were observed at the rainforest site,with an average boundary layer concentration of 0.55± 0.2 nmolmol–1. Also acetic and formic acids showed relatively lowaverage boundary layer mixing ratios; 1.1± 0.4 nmolmol–1 and 1.4± 0.5 nmol mol–1,respectively. Significant correlations were found between both acids andbetween the acids and hydrogen peroxide, suggesting an atmospheric source forthe acids.From the available observations we discuss possible implications of ourmeasurements for the O3, HO2, and NOx budgetsand concentrations in the boundary layer. We conclude that, despite the highsolar irradiation, relatively low levels of O3,H2O2, HCOOH and CH3COOH are observed in theboundary layer of the rainforest of Surinam, probably due to low levels ofNOx and high levels of VOCs, which leads to loss of OH andHO2 radicals. Additionally, high deposition rates of these gasesoccur to the forest vegetation. 相似文献
58.
A one-dimensional photochemical model was used to explore the role of chlorine atoms in oxidizing methane and other nonmethane hydrocarbons (NMHCs) in the marine troposphere and lower stratosphere. Where appropriate, the model predictions were compared with available measurements. Cl atoms are predicted to be present in the marine troposphere at concentrations of approximately 103 cm-3, mostly as a consequence of the reaction of OH with HCl released from sea spray. Despite this low abundance, our results indicate that 20 to 40% of NMHC oxidation in the troposphere (0–10 km) and 40 to 90% of NMHC oxidation in the lower stratosphere (10–20 km) is caused by Cl atoms. At 15 km, NMHC-Cl reactions account for nearly 80% of the PAN produced.The model was also used to test the longstanding hypothesis that NOCl is an intermediate to HCl formation from sea salt aerosols. It was found that the NOCl concentration required (10 ppt) would be incompatible with field observations of reactive nitrogen and ozone abundance. Chlorine nitrate (ClONO2) and methyl nitrate (CH3ONO2) were shown to be minor components of the total NO
y
abundance. Heterogeneous reactions that might enhance photolysis of halocarbons or convert ClONO2 to HOCl or Cl2 were determined to be relatively unimportant sources of Cl atoms. Specific and reliable measurements of HCl and other reactive chlorine species are needed to better assess their role in tropospheric chemistry. 相似文献
59.
D. D. Parrish D. W. Fahey E. J. Williams S. C. Liu M. Trainer P. C. Murphy D. L. Albritton F. C. Fehsenfeld 《Journal of Atmospheric Chemistry》1986,4(1):63-80
The mixing ratios for ozone and NOx (NO+NO2) have been measured at a rural site in the United States. From the seasonal and diurnal trends in the ozone mixing ratio over a wide range of NOx levels, we have drawn certain conclusions concerning the ozone level expected at this site in the absence of local photochemical production of ozone associated with NOx from anthropogenic sources. In the summer (June 1 to September 1), the daily photochemical production of ozone is found to increase in a linear fashion with increasing NOx mixing ratio. For NOx mixing ratios less than 1 part per billion by volume (ppbv), the daily increase is found to be (17±3) [NOx]. In contrast, the winter data (December 1 to March 1) indicate no significant increase in the afternoon ozone level, suggesting that the photochemical production of ozone during the day in winter approximately balances the chemical titration of ozone by NO and other pollutants in the air. The extrapolated intercept corresponding to [NOx]=0 taken from the summer afternoon data is 13% less than that observed from the summer morning data, suggesting a daytime removal mechanism for O3 in summer that is attributed to the effects of both chemistry and surface deposition. No significant difference is observed in the intercepts inferred from the morning and afternoon data taken during the winter.The results contained herein are used to deduce the background ozone level at the measurement site as a function of season. This background is equated with the natural ozone background during winter. However, the summer data suggest that the background ozone level at our site is elevated relative to expected natural ozone levels during the summer even at low NOx levels. Finally, the monthly daytime ozone mixing ratios are reported for 0[NOx]0.2 ppbv, 0.3 ppbv[NOx]0.7 ppbv and 1 ppbv[NOx]. These monthly ozone averages reflect the seasonal ozone dependence on the NOx level. 相似文献
60.
A nonlinear box system describing ozone photochemistry in the stratosphere is presented. Influences of pollutants, such as
odd chlorine (Clx) and odd nitrogen (NOx) discharged by human activities, on photochemical states of the system are investigated in detail. The results show that
the solutions of the box system constitute a ‘cusp’ catastrophe manifold in the state-parameter space. An increase of about
30% for Clx source strength or a decrease of about 30% for NOx source strength from their current level may lead to catastrophic transition and results in a reduction of ozone concentration
about 50 times.
Project supported by the National Natural Science Foundation of China and Laboratory for Aeronomy and Global Environmental
Observation of IAP. 相似文献