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The temporal and spatial characteristics of the aerosol optical depth (AOD) in the Western Pacific Ocean are analyzed using the field observation data and AVHRR remote sensing data. The observation AOD shows a significant north-south difference with a boundary of 25°N. In the north, the AOD spectral distribution shows a feature of decrease with the increase of wavelength in the range of 440–870 nm. In the south, the AOD maximum is at 500 nm. The average AOD (440) in the north is 0.177 larger than that in the south. The northern average Ångström exponent (α) is 3.2 times as large as that of the south. In terms of climatology, as the subtropical high ridge moves northward up to 12° from February to August, the location of AOD(630) maximum around 35°N moves northward by 10.5°. In addition to the northern maximum, the zonal mean of AOD(630) from AVHRR shows another maximum, located at 10°N. The AOD(630) at 35°N reaches its maximum in April, while the AOD(630) at 10°N reaches its maximum in March. The multi-year variation of AOD(630) at 35°N is consistent with that at 10°N with a correlation coefficient of 0.77. Research on the month of the climatological AOD(630) maximum at around 10°N shows that it is attributed to the joint action of aerosols from the sea south of 10°N and East Asia. • There exists a significant north-south difference in terms of aerosol spectral distribution. • The change of the spatial distribution of AOD is controlled by the Subtropical High. • The mid-low latitude maximum of AOD is affected by East Asian aerosol. [ABSTRACT FROM AUTHOR]

KCTf3, a commercially available, easily handled neutral salt, enhanced the reaction rates and the chemical yields of a wide spectrum of cationic metal catalyzed reactions, ranging from traditional Lewis acid catalysis to transition metal catalysis. [ABSTRACT FROM AUTHOR]

Due to dense matrix and serious heterogeneity, the water flooding development effect is poor in Qiaojiaowa block, Yanchang Oilfield. Therefore, CO2 indoor flooding experiment is carried out to potentially evaluate CO2 flooding and water alternating gas (WAG) on the basis of water flooding, and optimize the injection parameters such as injecting velocity, slug size and the ratio of gas and water. Besides, yield predictions of water flooding, water flooding based on well optimized, CO2 flooding and WAG after injection CO2 for 5 years are conducted using numerical simulation. Experimental results show that it is a large potential in target block for CO2 flooding after water flooding. The enhanced oil recovery (EOR) improvement of CO2 flooding and WAG are 8. 43% and 20. 95% respectively compared with water flooding. Oil recovery with WAG increases first and then decreases with three injection parameters increase. The best injected velocity, slug size and gas-water ratio are 0. 73 mL/min, 0. 1 PV and 1 : 1. Simulation results show that the EOR improvement of water flooding based on well optimized, CO2 flooding and WAG after injecting CO2 for five years after developing 15 years are 0. 77%, 13. 81% and 12. 98% respectively compared with water flooding. The suggested production plan is WAG after injecting CO2 for five years. [ABSTRACT FROM AUTHOR]

3D woven composites are considered as the ideal materials for subsea pressure shells owing to their exhibit excellent out-of-plane properties of delamination resistance and compressive damage resistance, which greatly improves the bearing capacity of the structure. This paper presents the influence of the radius-to-thickness ratio and the initial defects on the 3D woven composite spherical shells subjected to external hydrostatic pressure using the multi-scale finite element and theoretical methods. Two kinds of typical 3D woven structures, curved shallow-crossing linking 2.5D, and straight shallow-crossing linking 2.5D, are selected. The results show that the proposed multi-scale finite element method is capable of accurately predicting the strength and buckling behavior of 3D woven composite spherical shells under external hydrostatic pressure loadings, validated by the comparison of theoretical predictions. Furthermore, the fabric structures, radius-to-thickness ratio, and initial defects affect importantly the mechanical behavior of 3D woven composites pressure shells. [ABSTRACT FROM AUTHOR]

In order to solve the disadvantages of toxic, combustible, lower density of oil-based paraffin remover, and low paraffin removal efficiency and control effect poor stability of emulsion paraffin inhibitor of water-base paraffin remover, based on the structure of hydrophilic and/or lipophilic group in surfactant, the wax crystal modifier dispersed in water homogeneously. Waterbase wax crystal modifier type paraffin inhibitor has been developed. It has advantages of low toxicity, incombustible, high density, high efficiency of paraffin removal and paraffin control effect. The laboratory result showed that viscosity reduction rate and dynamic wax inhibiting rate were both more than 70% respectively under the best proportion condition. The field result indicated that it could decrease the times of washing well and improve the production of oil well by using continuous dosing. [ABSTRACT FROM AUTHOR]

Urbanization has resulted in obvious changes in plant species diversity. We analyzed the dynamics of ruderal species diversity in Harbin over the past half century using historical data collected in 1955 and data of the present spatial distribution in 2010-2011. The results show that, the number of ruderal species decreased from 611 to 175 with remarkable tendency of decreasing in perennial species and increasing in winter annual species in the past half century, which caused the shift of life form spectrum from perennial mono-dominant type to summer annual and perennial co-dominant type. Meanwhile, the proportion of tropical originated species increased and the proportion of temperate originated species decreased which were considered to relate with the increase of temperature in urban area during the past half century. Moreover, there was a distinct decrease of the proportion of aquatic and hygrophytic ruderal species while an increase of mesic and xeric ruderal species which suggested a drought trend in urban habitats that consistent with the change of land use characterized as decrease of natural water bodies and wetlands and increase of urban land. Comparison of ruderal species along urbanization gradient also got the similar results with the above results from analysis on temporal scales and confirmed the effect of urbanization on decreasing plant richness. Our results suggested that land use change combined with its effect on temperature and disturbance regimes in urban habitats preferred species with short life span, high drought tolerance, fast growth rates and high seed yields. [ABSTRACT FROM AUTHOR]

The diffuse attenuation coefficient ( K) for downwelling irradiance is calculated from solar irradiance data measured in the Arctic Ocean during 3rd and 4th Chinese National Arctic Research Expedition (CHINARE), including 18 stations and nine stations selected for irradiance profiles in sea water respectively. In this study, the variation of attenuation coefficient in the Arctic Ocean was studied, and the following results were obtained. First, the relationship between attenuation coefficient and chlorophyll concentration in the Arctic Ocean has the form of a power function. The best fit is at 443 nm, and its determination coefficient is more than 0.7. With increasing wavelength, the determination coefficient decreases abruptly. At 550 nm, it even reaches a value lower than 0.2. However, the exponent fitted is only half of that adapted in low-latitude ocean because of the lower chlorophyll-specific absorption in the Arctic Ocean. The upshot was that, in the case of the same chlorophyll concentration, the attenuation caused by phytoplankton chlorophyll in the Arctic Ocean is lower than in low-latitude ocean. Second, the spectral model, which exhibits the relationship of attenuation coefficients between 490 nm and other wavelength, was built and provided a new method to estimate the attenuation coefficient at other wavelength, if the attenuation coefficient at 490 nm was known. Third, the impact factors on attenuation coefficient, including sea ice and sea water mass, were discussed. The influence of sea ice on attenuation coefficient is indirect and is determined through the control of entering solar radiation. The linear relationship between averaging sea ice concentration (ASIC, from 158 Julian day to observation day) and the depth of maximum chlorophyll is fitted by a simple linear equation. In addition, the sea water mass, such as the ACW (Alaskan Coastal Water), directly affects the amount of chlorophyll through taking more nutrient, and results in the higher attenuation coefficient in the layer of 30-60 m. Consequently, the spectral model of diffuse attenuation coefficient, the relationship between attenuation coefficient and chlorophyll and the linear relationship between the ASIC and the depth of maximum chlorophyll, together provide probability for simulating the process of diffuse attenuation coefficient during summer in the Arctic Ocean. [ABSTRACT FROM AUTHOR]

Additives that are good hydrogen-bondacceptors increase the efficiencyof gold-catalyzed reactions in those instances where protodeaurationis the rate-determining step. The efficiency of additives capableof hydrogen-bonding-assisted protodeauration correlated with theirstanding in a scale of hydrogen bonding basicity (measured by pKBHX). All additives used in the study are commerciallyavailable. [ABSTRACT FROM AUTHOR]

This paper establishes a mathematic model of a CO2 two-phase ejector to investigate flow distribution in the components of a mixing chamber and diffuser. The suction chamber was modeled using the characteristic line method to describe the development process of the supersonic expansion wave, and the mixing chamber, as well as diffuser models, were built based on the double-flow model. The reliability of the model was verified by experimental data. The distributions of flow parameters along the axis of the mixing chamber and diffuser were analyzed under different expansion ratios of the ejector. Structure optimizations of the mixing chamber and diffuser were conducted. The results showed that the primary flow temperature gradually increased along the axis of the mixing chamber and diffuser, but the Mach number distribution decreased for a certain ejector expansion ratio. The temperature and Mach number of the secondary flow showed the opposite trend. Moreover, at the initial stage of mixing, the fluid pressure increased rapidly, and the Mach number of the primary flow decreased rapidly. The gas-phase fraction of primary flow increased gradually in the mixing chamber and was stable in the diffuser. When the length–diameter ratio of the mixing chamber was about 10.8–12, it was beneficial to mix uniformity, and when the expansion angle of the diffuser was 4–6°, the ejector had a better ejector efficiency. [ABSTRACT FROM AUTHOR]