LOCAL HYDRODYNAMICS IN AN EXTERNAL LOOP AIRLIFT SLURRY REACTOR WITH AND WITHOUT A RESISTANCE-REGULATING ELEMENT

The hydrodynamic behavior of an external loop airlift slurry reactor (ALSR) with and without a resistance-regulating element was studied with a fiber optic probe and ultrasound Doppler velocimetry. The influences of the superficial gas velocity and solid holdup on the global gas holdup and radial profiles of the suspension circulation velocity in the downer and of gas holdup, bubble size, and bubble rise velocity in the riser were studied. Local measurements allow a better understanding of the flow behavior in the reactor and can be used for CFD modeling and validation. Experimental results show that the resistance-regulating element increases the gas holdup and decreases the suspension circulation velocity, indicating that an optimum design of the flow resistance is needed to obtain the maximum gas-liquid volumetric mass transfer coefficient for a specific superficial gas velocity. A high superficial gas velocity and low solid holdup are favorable for increased uniformity of the radial profile of the gas holdup and bubble rise velocity. Hydrodynamic models that predict the gas holdup and suspension circulation velocity were developed for an ALSR with and without a resistance-regulating element. Good agreement was obtained between measured and predicted values.     

工业废水中氨氮处理方法比较分析

氨氮已作为我国"十二五"水污染控制约束性指标。针对含氨氮废水进行处理,并实现达标排放是当前研究的热点。基于已有的实际工业废水处理应用案例,对比分析了吹脱法、吸附法、化学沉淀法、折点氯化法、生物脱氮法等处理工业氨氮废水的适用条件(进水氨氮浓度、处理时间、温度、pH等)和处理效果,并总结了不同处理方法的工艺特点及其优缺点,可以为氨氮废水处理工艺和参数选择提供参考。     

Influence of technical parameters on strength and ductility of AlSi9Cu3 alloys in squeeze casting

An orthogonal test was conducted to investigate the influence of technical parameters of squeeze casting on the strength and ductility of AlSi9Cu3 alloys. The experimental results showed that when the forming pressure was higher than 65 MPa, the strength (σ_b) of AlSi9Cu3 alloys decreased with the forming pressure and pouring temperature increasing, whereas σ_b increased with the increase of filling velocity and mould preheating temperature. The ductility (δ) by alloy was improved by increasing the forming pressure and filling velocity, but decreased with pouring temperature increasing. When the mould preheating temperature increased, the ductility increased first, and then decreased. Under the optimized parameters of pouring temperature 730 °C, forming pressure 75 MPa, filling velocity 0.50 m/s, and mould preheating temperature 220 °C, the tensile strength, elongation, and hardness of AlSi9Cu3 alloys obtained in squeeze casting were improved by 16.7%, 9.1%, and 10.1%, respectively, as compared with those of sand castings.     

新型净水剂的制备及其在高温高压SAGD采出水中的应用

介绍了新型净水剂的制备,并用红外光谱、热重分析等方法分析了该新型净水剂的结构及热稳定性;利用该净水剂采用自制的可在高温高压下评价净水剂除油性能的装置处理呈高温、高压状态,且含油量高的超稠油SAGD采出水,考察了该净水剂在不同情况下的除油效果。结果表明:产品具有良好的热稳定性,除油性能良好,除油速度快,除油率可达99%以上。     

食品分析实验教学改革与实践

文章根据目前食品质量安全问题和传统食品分析实验教学的不足提出了改革食品分析实验教学的必要性,从实验内容、实验教学方法、实验环节、实验成绩评定和实验室开放等方面进行了改革与实践。证明改革提高了学生的学习积极性和综合素质,有效地培养了学生的实践能力和创新能力。     

国产AH-90重交通道路沥青的感温性研究

以SHRP试验方法为主要手段，研究了几种有代表性的国产AH-90重交通道路沥青的感温性，通过对沥青在不同老化阶段，不同温区下的感温性指标的研究，表明老化对不同沥青的感温性影响程度差别不大，沥青在低温区的感温性与高中温区的感温性有些不同，国产的AH-90重交通道路沥青具有良好的感温性。     

Predictive Microbiology for Monitoring Spoilage of Dairy Products with Time-Temperature Integrators

Time/temperature integrators (TTI) have a potential for monitoring time-temperature history of perishable foods, including dairy products. To correlate the end of shelf life of dairy products with different TTI's, kinetic data for growth of a dairy spoilage microorganism was obtained. Both Arrhenius and square root equations were used to model the growth of Pseudomonas fragi. A significant negative history effect was observed for P. fragi growth rate whereas history effect was positive on the lag phase, under certain nonisothermal conditions. A correlation scheme of P. fragi growth was developed with the TTI response. The application of TTI's for dairy products is feasible despite the history effects.     

快堆材料试验回路的静力分析

该回路有多个环形管系、布置紧凑、运行温度高。原设计未考虑支撑,因此“安全问题”比较突出。根据SDGJ6-78规定。利用PSDP程序,对此回路进行了一次、二次或一次加二次应力验算,改进了原设计,并对支撑作了合理布置。计算表明在给定条件下运行是安全的。     

彩虹全息术综合狭缝的理论分析

本文从像面光场移动的观点对一步无狭缝彩虹全息术中平移物体和透镜形成的综合狭缝进行了理论分析，并提出了一种新的综合狭缝二步彩虹全息方法．     

Characteristics and Microstructure of Graphite Encapsulated Iron Nanoparticles

The graphite encapsulatedα-Fe particles were prepared by reduction of stage-2 and stage-3 FeCl 3 graphite intercalation compounds(GICs)with metallic potassium.X-ray diffraction analysis(XRD),energy dispersive X-ray spectroscopy(EDS)investigation and transmission electron microscopy(TEM) observation show that the reduction products of stage-2 FeCl 3 -GICs contains more abundantα-Fe nanoparticles than those of stage-3.High-resolution TEM(HRTEM)observation reveals that the nanoparticle ofα-Fe was polycrystals or twins,which was real or quasi two-dimension in shape,and whose space orientation was strictly controlled by the graphene.Based on the experiment results,a possible growth model of the graphite encapsulatedα-Fe was proposed.