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101.
Simulation of the Direct Radiative Effect of Mineral Dust and Sea Salt Aerosols in a Doubled Carbon Dioxide Climate 下载免费PDF全文
The authors examine the equilibrium climatic response to the direct radiative effect(DRE)of mineral dust and sea salt aerosols in a doubled-CO2climate with two-way coupling of aerosol-climate interactions.In response to the drier and windier conditions,dust emissions increase by 26%in the Sahara Desert and by 18%on the global scale relative to present day.Sea salt emissions increase in high latitudes(60°)but decrease in middle latitudes(30°–60°)of both hemispheres due to the poleward shift of westerlies,leading to a 3%decrease in global emissions.The burdens of dust and sea salt increase by 31%and 7%respectively,because reductions in rainfall over the tropical oceans increase the lifetime of particles in the warmer climate.The higher aerosol loading in the doubled-CO2climate reinforces aerosol DRE by0.2 W m 2,leading to an additional cooling of 0.1°C at the surface compared with the climatic effects of aerosols in present day.The additional cooling from changes in natural aerosols compensates for up to 15%of the regional warming induced by doubled CO2. 相似文献
102.
103.
LIU Lingyun GUO Haiyan SUN Qi 《中国海洋大学学报(英文版)》2006,5(3):269-272
Portal water injection sheet pile (PWISP), as a retaining wall, appeared in seashore engineering in 2000. Although there have been many systematic methods addressing the issue, there are very few focusing on the new structure because of the difficulties in defining the earth pressure between the two piles. A new method is proposed in this paper to obtain the earth pressure between the PWISPs. Stability analysis against overturning follows as a consequence. Using Finite Element Analysis (FEA) software ANSYS, both the nonlinear characteristics of the soil and those of the contact elements are taken into account to obtain the earth pressure distribution on the contact surface. Based on the results of the FEA, Rankin's theory and the slip plane theory, the formula of the earth pressure on the inner surfaces between the piles is given. Assuming the PWISP as the analysis object and the earth pressure as an outside force acting upon it, the equation of stability against overturning of the PWISP is presented. Finally, some parameters are discussed about the stability of the PWISP against overturning, such as the embedded depth of the front pile, the distance between the two rows of piles, the internal friction angle and the cohesion of the earth. The results show that the increase of the cohesion and the internal friction angle will decrease the distance and the embedded depth, and therefore enhance the stability against overturning. Specifically, when the distance is 1/3-2/3 of the maximal excavation depth, the two rows of piles give the best performance in stability. 相似文献
104.
流动注射—试钛灵分光光度法测定岩石中全铁和钛,是在原有方法的基础上,引进了流动注射技术,从而提高了样品的分析速度、准确度、精密度,并使样品测试的线性范围有了明显的改善。本方法快速、灵敏、简便、可靠,每小时提供110个测试数据,其铁、钛的相对标准偏差分别为0.82%和2.87%。 相似文献
105.
本文对四川省巴中县莲花山,从1954年开始,在调查研究和规划的基础上,根据造林地条件,提出马尾松栽培技术,取得明显成效。该经验对类似山区有借鉴参考价值。 相似文献
106.
This paper describes the application of the Powell algorithm to the optimization of a flow injectionsystem configuration.The performance of this algorithm has been compared with the modified simplexmethod.The system studied is the determination of ammonia,based on the indophenol blue reaction.Alinear combination of sensitivity and sample throughput is used as the objective function because of itssimultaneous optimization capability.Results obtained show that the proposed method may reach theoptimal conditions with a lower number of experimental evaluations. 相似文献
107.
We make a statistical analysis of the periodsP and period-derivativesP of pulsars using a model independent theory of pulsar flow in theP-P diagram. Using the available sample ofP andP values, we estimate the current of pulsars flowing unidirectionally along theP-axis, which is related to the pulsar birthrate. Because of radio luminosity selection effects, the observed pulsar sample
is biased towards lowP and highP. We allow for this by weighting each pulsar by a suitable scale factor. We obtain the number of pulsars in our galaxy to
be 6.05−2.80
+3.32 × 105 and the birthrate to be 0.048−0.011
+0.014 pulsars yr−1 galaxy−1. The quoted errors refer to 95 per cent confidence limits corresponding to fluctuations arising from sampling, but make no
allowance for other systematic and random errors which could be substantial. The birthrate estimated here is consistent with
the supernova rate. We further conclude that a large majority of pulsars make their first appearance at periods greater than
0.5 s. This ‘injection’, which runs counter to present thinking, is probably connected with the physics of pulsar radio emission.
Using a variant of our theory, where we compute the current as a function of pulsar ‘age’ (1/2P/P), we find support for the
dipole braking model of pulsar evolution upto 6 × 106 yr of age. We estimate the mean pulsar braking index to be 3.7−0.8
+0.8. 相似文献
108.
A membrane-discriminated gas phase analyzer is proposed for multicomponent determinations. Nitrogengas flows countercurrent through outer and inner channels in a tube-in-tube arrangement. The onlycommunication between the two channels occurs through a 500μm aperture covered by a porous PTFEmembrane. A mixture of organic compounds (up to four components) is injected into the inner channelby a heated backflushed injector and the sample components diffusing into the outer channel aremonitored by a flame ionization detector (FID). A calibration set, consisting of pure components, binary,ternary and quaternary mixtures (a total of 64 samples), provides the known data base: temporal profilesof the FID output as a function of sample composition, Although the overall response behavior is nota linearly additive function of individual analyte concentrations, the use of successive inverse multiplelinear regression (while continually altering the choice of the calibration samples considered for theforward regression, on the basis of the most recent values of the predicted unknown sample composition)is shown to yield analytical results for unknown samples that are in good agreement with their true values. 相似文献
109.
Kang-tsung Chang 《The Professional geographer》1989,41(3):314-328
Japan is the most important foreign investor in the United States. Japanese companies are trade-oriented and have ownership-specific advantages in select industries; their US investment is aimed at protecting their market share. The distribution of Japanese plants correlates well with US manufacturing, except that the West Coast and states that aggressively sought Japanese investment have more employees in Japanese plants. Japanese presence in US manufacturing is most prominent in consumer electronics, steel, automobiles, and high-technology industries. 相似文献
110.
The Meixner functions are utilized to relate the effective rainfall, the direct runoff and the unit hydrograph through linkage equations. The linkage equations are then employed to derive the unit hydrograph for given rainfall-runoff data on a small agricultural watershed. These functions are tested with regard to their ability to reproduce and predict the direct runoff hydrograph. The Meixner functions are found to be an effective analytical tool for hydrograph synthesis. Further, they compare well with the least squares and linear programming methods of the unit hydrograph derivation. 相似文献