南黄海海水中悬浮体垂向分布类型及跃层

海水中悬浮体的垂向分布并非上下均匀,而是具有明显的层化现象,这种情况与海水中的温度、盐度、密度等物理性质的层化现象一样,不是偶然的,而是常年存在的,同时,悬浮体含量的层化分布对于海水的某些物理性质有较大影响。

阻隔技术在高性能农药瓶中的应用

介绍了目前比较常见的生产高阻隔农药瓶的方法。

Multilayer distribution of carbon dioxide system in surface water of the Yellow Sea in spring

Surface water can be divided into three layers from top downward： surface microlayer （SML, thickness≤50 μm）, subsurface layer （SSL, ≈25 cm） and surface layer （SL, l-5m）, among which the SML plays an important role on sea-air interaction because of its unique physical-chemical property. Carbon dioxide system including DIC （dissolved inorganic carbon）, Alk （alkalinity）, pH and pCO： （partial pressure of CO2） in multilayered waters of the Yellow Sea was studied for the first time in March and May 2005. The results show that： DIC and Alk are obviously enriched in SML. The contents ofDIC, Alk and pCO2 become lower in turn from SML, SSL to SL, higher in March and lower in May, whereas for pH it was opposite. The relationship between DIC and Alk is clearly positive, but negative between pH and pCO2. Meanwhile, pCO2 and temperature/salinity is also in positive relation, pCO2 decreases with latitude increase. DIC and Alk show a similar variation trend with the maximum at 02：00-03：00, but pH and pCO2 show an opposite pattern. In addition, the distribution patterns are similar to each other in the three layers. The Yellow Sea is shown to be a sink of atmospheric CO2 in spring by two methods： （1） comparing pCO2 in seawater and atmosphere; （2） turning direction of ＂pH-depth＂ curve. Calculation on the base of pCO2 data in SML in four models shows that carbon flux in spring in the area was about -6.96×10^6 t C.

Analysis of the dialectical relation between top coal caving and coal-gas outbtu rst

According to the different engineering mechanical states of top coal caving andnormal stoping of gaseous loose thick coal seams,the dialectical relation between thiscaving method and dynamic disasters was analyzed by simulating the change of stressstates in the process of top coal initial caving with different mining and caving ratios basedon the ANSYS10.0.The variation of elastic energy and methane expansion energy duringfirst top coal caving was analyzed by first weighting and periodic weighting and combiningwith coal stress and deformation distribution of top coal normal stoping as well as positiveand negative examples in top coal caving of outburst coal seam.The research shows thatthe outburst risk increases along with the increase of the caving ratio in the initial miningstage.In the period of normal stoping,when the mining and caving ratio is smaller than1:3 and hard and massive overlying strata do not exist (periodic weighting is not obvious),it is beneficial to control ground stress leading type outburst.Thus,it is unreasonable toprohibit top coal caving in dangerous and outburst prone areas.

Effect of agitation on the characteristics of air dense medium fluidization

In order to study the effect of agitation on the characteristics of air dense medium fluidization, we designed and constructed an agitation device. Analyses were then conducted on the fluidization characteristics curves, the bed density stability and the average bubble rise velocity Uaunder different agitation conditions. The results indicated that a lower bed pressure drop(without considering lower gas velocity in a fixed bed stage) and higher minimum fluidized velocity are achieved with increasing agitation speed.The height d(distance between the lower blades and air distribution plate) at which the agitation paddle was located had a considerable effect on the stability of the bed density at 9.36 cm/s < U < 10.70 cm/s. The higher the value of d, the better the stability, and the standard deviation of the bed density fluctuation r dropped to 0.0364 g/cm^3 at the ideal condition of d = 40 mm. The agitation speed also had a significant influence on the fluidization performance, and r was only 0.0286 g/cm^3 at an agitation speed of N = 75 r/min. The average bubble rise velocity decreased significantly with increasing agitation speed under the operating condition of 1.50 cm/s < U–U_(mf)< 3.50 cm/s. This shows that appropriate agitation contributes to a significant improvement in the fluidization quality in a fluidized bed, and enhances the separation performance of a fluidized bed.

Research and optimization on laminated steel tube column-concrete beam joints with outer stiffening ring

In practical design,the joints with outer stiffening ring were used to connect concrete beams and laminated steel tube columns.The seismic behavior of joints with outer stiffening ring with various types was studied based on experiments.The bearing capacity,rigidity,ductility,energy dissipation capacity,deformation property and strain distribution of the joints with outer stiffening ring with various types were comprehensively evaluated based on the test results of three specimens under quasistatic cyclic loading and finite element analysis.The test results showed that the failure mode,hysteretic behavior,bearing capacity and rigidity degradation of the joints with outer stiffening ring with various types were nearly identical.Furthermore,the strain distribution of the outer stiffening ring of the three joints was nearly the same.The detailing recommendation for the outer strengthening rings was proposed for the concrete beam-laminated steel tube column joints with outer stiffening ring,in order to ensure the good seismic capacity of the joints.

Simulation of tin penetration process in the surface layer of soda-lime-silica float glass

Based on the analysis of tin penetration mechanism in the float glass process, the oxidation model of stannous ion is constructed considering the oxygen activity and the redox reaction in the glass surface layer. The calculation of stannous ion's oxidation rate makes it possible to predict both stannous and stannic ion's concentrations independently. And it is also the necessary precondition for the numerical verification of tin penetration mechanism. Coupled diffusion simulation method is established to simulate the penetration process of both stannous and stannic ions simultaneously. The result shows that when the green glass is formed in the reducing atmosphere in tin bath, the stannic ion is accumulated at the position where oxygen activity changes sharply. Satellite peak (internal local concentration maximum) occurs in the tin concentration profile of green glass, which is quite different from that in low iron glass. Compared with gradually cooling temperature regulation, the tin penetrated shifts to greater depth and the depth and magnitude of the satellite peak also increase when reheating temperature regulation is applied. In order to reduce the amount of penetrated tin, the residual time in the high temperature region should be shortened.

Spatio-temporal modelling of the effect of selected environmental and land-use factors on acid grassland vegetation

Acid grasslands are threatened both by agricultural intensification with nutrient addition and increased livestock densities as well as by land abandonment.In order to understand and quantify the effect of selected environmental and land-use factors on the observed variation and changes in the vegetation of acid grasslands,large-scale spatial and temporal pin-point plant cover monitoring data are fitted in a structural equation model.The important sources of measurement and sampling uncertainties have been included using a hierarchical model structure.Furthermore,uncertainties associated with the measurement and sampling are separated from the process uncertainty,which is important when generating ecological predictions that may feed into local conservation management decisions.Generally,increasing atmospheric nitrogen deposition led to more grass-dominated acid grassland habitats at the expense of the cover of forbs.Sandy soils were relatively more acidic,and the effects of soil type on the vegetation include both direct effects of soil type and indirect effects mediated by the effect of soil type on soil pH.Both soil type and soil pH affected the vegetation of acid grasslands.Even though only a relatively small proportion of the temporal variation in cover was explained by the model,it would still be useful to quantify the uncertainties when using the model for generating local ecological predictions and adaptive management plans.