铝电解中阳极涂层与磷生铁改性剂的综合优化实验

提高炭素阳极的强度和抗氧化性是目前铝电解研究的热点和难点。本文总结了在某铝厂400 kA系列磷生铁中加入改性剂和在阳极炭素表面涂盖耐高温防氧化涂层涂料的实验。加入磷生铁改性剂浇筑出的磷生铁具备更好的延展性和膨胀性,使炭块与钢爪之间接触电阻减少,钢爪与炭块间的连接更紧密,减少了脱极的几率,降低了铁-碳压降;使用防氧化涂层材料,提高了铝电解电流效率,大大减少了炭块的掉渣量,延长了炭素阳极的使用周期。

园林工程水土保持植物配置措施研究

植物配置是园林工程中的关键环节,在确保园林景观整体效果及生态价值的同时,还要充分体现其艺术性、多样性,为人们营造一个多彩的景观环境。在植物配置中合理的使用水土保持技术,不仅有利于实现园林绿化的设计功能,提高园林景观的观赏价值,而且对于维持园林生态平衡具有极为重要作用。因此,从园林工程水土保持植物的选择及筛选原则出发,对水土保持植物配置措施进行了深入研究,以期能够为相关人员提供一定的借鉴与参考。

Phosphorus Transfer and Distribution in a Soybean-Citrus Intercropping System

A mini-plot field experiment was conducted on a loamy clay Oxisol to compare and evaluate P absorption and transfer in plant organs and P movement in soil profile at three P application depths under the soybean-citrus intercropping versus the monoculture using a 32P tracer technique. Total P absorption (Pt) by soybean and P accumulation (Pa) in soybean organs decreased significantly (P < 0.05) under the intercropping in contrast to the monoculture. With intercropping, when 32P was applied in topsoil (15 cm soil layer), total 32P absorption (32Pt) in soybeans was significantly lower (P < 0.05), but when 32P was applied to deeper soil layers (35 or 55 cm soil layer), 32Pt in soybeans was significantly greater (P < 0.05). The percentage of P in leaves to total P (Pa/Pt) and 32P in leaves to total 32P (32Pa/32Pt) for soybean were (?) 25% and those of root (?) 12%. When P was applied in topsoil and 55 cm soil layer, no significant differences were found between intercropping and monoculture for Pt of citrus. The P absorbed by citrus was transferred rapidly to the growing organs of aboveground during the experiment, and the speed of transferring to the growing organs slowed when P was applied to the deeper soil layers. In intercropping, P mobility was heightened in the soil profile, and P in deeper soil layers moved up to topsoil more rapidly.

Plant Phosphorus Uptake in a Soybean-Citrus Intercropping System in the Red Soil Hilly Region of South China

A field microplot experiment was conducted in the red soil hilly region of South China to evaluate plant phosphorus (P)uptake under soybean and citrus monoculture and the soybean-citrus intercropping system using the 32P tracer technique.P fertilizer was applied at three depths(15,35,and 55 cm).The experimental results showed that the planting pattern and 32P application depth significantly affected the characteristics of P uptake by soybean and citrus.Under the soybean-citrus intercropping system,considerable competition was observed when the 32P fertilizer was applied to the topsoil(15 cm);therefore,the 32P recovery rate declined by 41.5%and 14.7%for soybean and citrus,and 32P supplying amount of topsoil to soybean and citrus decreased by 346.8 and 148.1 mg plot-1,respectively,compared to those under the monoculture.However,32P recovery of soybean was promoted when 32P fertilizer was applied to the deeper soil layers (35 and 55 cm)under soybean-citrus intercropping.Under the soybean monoculture,32P fertilizer could hardly be used by soybean when 32P fertilizer was applied at the 55 cm depth or below,with the recovery rate being less than 0.1%;it was up to 0.253%by soybean under intercropping.The higher P recovery of soybean under soybean-citrus intercropping when P was applied in the deeper soil layers was because part of the P nutrient that the citrus absorbed from the deeper soil layers could be released into the topsoil and then it could be used by the soybean.

浸后铝用阳极焙烧热解行为研究

采用Coats-Redfern近似的热解动力学分析模型,对浸后阳极进行了热重分析,比较三种升温速度下试样的失重特点。结果表明,浸后阳极失重过程分为三个阶段,降低升温速度可使沥青热解反应提前开始,并提前结束,减少热分解量,降低最大失重速率,提高残炭率。在沥青热解反应第二阶段适当降低升温速度,确保热解反应充分完成,有助于提高浸后焙烧后阳极的增重率以及各项物化性能,而在热解反应的第一阶段(室温~200℃)以及第三阶段(550~750℃)可适当提高升温速度,以减少浸后焙烧周期,减少焙烧能耗。浸渍剂沥青的热解反应属于一级反应,随着升温速度的降低,活化能呈减少趋势,反应更加容易进行,反应更充分。

铝电解槽不同投料量下氧化铝溶解的模拟及其温度响应（英文）

在铝电解下料过程中,氧化铝下料量影响一个下料周期结束后氧化铝颗粒的最终溶解量。本文基于OpenFOAM 计算平台,开发了铝电解槽中氧化铝颗粒传热、传质耦合溶解计算模型;利用Rosin-Rammler 分布函数得出氧化铝在不同下料量下的颗粒粒径分布,考虑下料区温度响应,对实际300 kA 铝电解槽中氧化铝颗粒在不同下料量下(0.6, 0.8, 1.0, 1.2, 1.4, 1.6 kg)的溶解过程进行数值模拟。模拟结果表明:随着下料量的增加,氧化铝累积溶解质量分数降低,快速溶解阶段所需的时间逐渐加长。当投料量分别为0.6 kg 和1.2 kg 时,电解质温度下降至出现回升所需时间最短。随着下料量的增加,快速溶解阶段的溶解速率先迅速上升,后逐渐减少。最佳下料量为1.2 kg。通过拟合氧化铝溶解特性曲线,得到了不同下料量下氧化铝累积溶解质量分数的拟合方程,可根据此方程评估氧化铝溶解情况及指导氧化铝的下料量和下料周期。

Characteristics of the Mesophyllous Cells in the Sheaths of Rice (Oryza sativa L.)

The photosynthesis of rice sheath plays a significant role to furnish rice yield, and it is accounted for 10 to 20% of the final yield. But, limited studies have been done to address this phenomenon and to characterize the mesophyllous cells of rice sheath and how it may attribute to the rice yield. In this paper, super hybrid rice Liangyoupeijiu, its parents Wumang 9311 and Peiai 64S, and hybrid rice Shanyou 63 were studied as the experimental materials, and the characteristics of the mesophyllous cells of rice sheaths were examined by microscopic and super-microscopic observation as well as chlorophyll absorption spectrums. The results showed that rice sheath was rich in the intact mesophyllous cells full of chloroplasts, grana and thylakoids, which were much the same as those of rice blade. The absorption spectrum curves of the Chl. a and b of the sheaths were similar to those of the blades. The stomatal density in the outer epidermises of the sheaths was comparable to those in the up- and down-epidermises of the blades. The significant tests proved that the amount of chloroplast per mesophyllous cell of the sheaths was almost the same as those of the blades, and the mesophyllous cells in the sheaths were also rich in chlorophylls. The chlorophyll content of rice sheath reached about 50% of the chlorophyll content of rice blade, and the P, of the sheath/the blade ranged from 13.60 to 34.57%. Therefore, rice sheath was also full of the intact photosynthetic apparatus similar to those in rice blade, and had capabilities of photosynthesis. The statistical analysis revealed that the physiological senescence of the photosynthetic apparatus in both the sheath and the blade of Liangyoupeijiu was significantly slower than those of the other varieties at the late stages. The profuse grain-filling stage was an inflexion point of the physiological senescence of the chloroplasts and the chlorophylls of both the blades and the sheaths.

替莫唑胺对胶质瘤细胞U251凋亡的影响

目的探究替莫唑胺对胶质瘤细胞U251凋亡的影响及其作用机制。方法 40、80、120μmol/L替莫唑胺培养U251细胞系48 h,观察形态变化,流式细胞术检测细胞凋亡率,实时荧光定量PCR(q RT-PCR)法检测caspase 3表达,用caspase3试剂盒检测caspase 3的活性,蛋白免疫印迹(Western blotting)法检测热休克蛋白90(HSP90)、p-HSP90、丝氨酸苏氨酸蛋白激酶(AKT)和p-AKT表达。结果替莫唑胺80、120μmol/L组细胞数目减少,细胞核体积明显缩小,染色质固缩。替莫唑胺80、120μmol/L组细胞凋亡率、caspase 3的表达水平和活性明显高于对照组,p-HSP90、p-AKT的表达水平明显低于对照组(P<0.05),呈剂量相关性。结论替莫唑胺能够促进胶质瘤细胞U251凋亡,可能是通过抑制HSP90和AKT表达来实现的。