几种典型红壤模拟降雨条件下的泥沙特征研究

泥沙是土壤侵蚀过程的产物,直接反映了土壤的侵蚀特征。本文利用人工模拟降雨,研究了南方几种典型母质发育红壤侵蚀泥沙的颗粒分布特征、不同粒级中胶结物质的种类和含量。研究结果表明,径流优先选择携带0.002~0.02 mm颗粒,该级别颗粒占泥沙总量的26.68%~60.33%。粘粒含量高的第四纪粘土红壤,泥沙中粗颗粒含量较高,且多为较稳定的团聚体;沙粒和粉粒含量较高的页岩红壤和花岗岩红壤侵蚀泥沙中单粒含量较高,且泥沙分散后粉粒和粘粒的含量高于原土壤。花岗岩红壤侵蚀泥沙中Fe_d,Al_d,Al_o和Si_o含量随泥沙粒径的增大而降低,而泥质页岩红壤和第四纪粘土红壤中,Fe_d,Al_d,Al_o含量随粒径增大而增加,因此其粗粒径泥沙具有较强的稳定性。侵蚀泥沙对有机质有富集作用,泥质页岩红壤和第四纪粘土红壤的粗颗粒对有机质的富集作用强于细颗粒。     

上流式斜流沉淀去除率公式的理论推导

结合斜流沉淀结构的特点，分析了流道内液芬布对颗粒沉淀过程的影响；污水中颗粒粒径分布对去除率的影响，从而理论上推导上流式斜流沉去除率的计算公式     

确定复杂形状旋转体拉延毛坯尺寸的计算机AutoCAD方法

提出了一种基于AutoCAD软件的确定复杂形状旋转体拉深毛坯直径的计算机方法,它操作严谨、结果准确,比原有的3种方法简捷、快速,具有良好的推广应用价值。     

双锥度锥形模设计

在冷镦生产中 ,当零件的头部变形较大时 ,通常采用大料及缩径的加工方法。使用该方法冷镦凹模寿命低。通过理论分析和大量的实验后 ,成功地采用双锥度锥形模加普通凹模的生产方式 ,生产头部变形较大的零件 ,取得了良好的效果 ,大大降低了零件的生产成本。     

Physicochemical characteristics of carbonaceous adsorbent for dioxin-like polychlorinated biphenyl adsorption

It has been known that dioxin-like polychlorinated biphenyls (DL-PCBs) are present in almost all types of environments worldwide. Activated carbon treatment has been expected for the removal of DL-PCBs because it is a simple and low-cost removal technology. In the present study, the physicochemical properties of activated carbon were investigated to identify the characteristics of 16 different types of activated carbon on adsorption properties for DL-PCBs. To accomplish this, micropore volume, and pore diameter were calculated by t-plot analysis and the mesopore volume was analyzed by the Barrett-Joyner-Halenda (BJH) method. In addition, the Brunauer-Emmett-Teller (BET) surface area, pH, metal elements, and surface acid functional groups were analyzed. Then, adsorption experiments using DL-PCB in hexane solution were conducted, and the relationship between adsorption and physicochemical properties of activated carbon was investigated. The results showed that activated carbons having a surface area of 700-1200 m² g⁻¹ and micropores with diameters of about 0.7-0.8 nm exhibited high activity for the adsorption of PCBs. The results also clearly showed that the mesopore volume of activated carbon influenced the adsorption rate and the equilibrium adsorption.     

Tree and stand growth of mature Norway spruce and European beech under long-term ozone fumigation

In a 50- to 70-year-old mixed stand of Norway spruce (Picea abies (L.) Karst.) and European beech (Fagus sylvatica L.) in Germany, tree cohorts have been exposed to double ambient ozone (2×O₃) from 2000 through 2007 and can be compared with trees in the same stand under the ambient ozone regime (1×O₃). Annual diameter growth, allocation pattern, stem form, and stem volume were quantified at the individual tree and stand level. Ozone fumigation induced a shift in the resource allocation into height growth at the expense of diameter growth. This change in allometry leads to rather cone-shaped stem forms and reduced stem stability in the case of spruce, and even neiloidal stem shapes in the case of beech. Neglect of such ozone-induced changes in stem shape may lead to a flawed estimation of volume growth. On the stand level, 2×O₃ caused, on average, a decrease of 10.2 m³ ha⁻¹ yr⁻¹ in European beech.     

Experimental research of flow rate and diffusion behavior of nature gas leakage underwater

In order to assess the potential risk of pipeline underwater leakage, a self-designed experimental setup is carried out to study the gas release rate and dispersion behavior in different release scenarios. A transparent organic glass tank with dimension of 1 m × 0.5 m × 0.5 m (height × width × length) was placed in a wind tunnel. The release pipeline made by stainless-steel with diameter of 25 mm were used to simulate for variation release depth. The different size and shape of leakage orifices in 1 mm, 3 mm, 5 mm in round and 3.5 × 2 mm, 7 × 1 mm in rectangle were designed for comparison. The medium of methane gas was released from the controllable cylinder. The variation parameters of flow rate and pressure were measured by a flow meter and pressure gauge respectively. A high speed camera was employed to recorded the phenomenology of dispersion characteristics and breakup process for a wide range of orifice size in the time-resolved images. The dynamic plume diameter on water surface was measured by a Vernier caliper placed above the water tank. The considered factors including orifice size, leakage pressure and water depth effect on gas flow rate and dispersion behavior was quantitative investigated. The fitting correlation between the gas flow rate and variation parameters can provide fundamental information for evaluation the hazard consequences of gas release in engineering application.     

鼓泡式反应器高径比对氨法烟气脱碳性能的影响

以N2和CO2混合气模拟燃烧烟气，研究了鼓泡反应器的高径比以及反应条件对氨法烟气脱碳性能的影响。实验结果表明:在相同高径比的条件下，CO2吸收率随氨水质量分数的增加、反应温度的升高而逐渐增大，随进气CO2体积分数和模拟烟气流量的增加而逐渐减小;CO2吸收率随高径比的增加而增大，在高径比为3.98、氨水质量分数为28%、进气CO2体积分数为10%、模拟烟气流量为1.0L/min、反应温度为40℃的条件下，CO2吸收率最高可达100%。