基于多步迭代算法的数字预失真技术

为了更好地补偿功率放大器的非线性,提出一种新型多步迭代算法来求取数字预失真器。新算法结合了多步迭代算法与频域削峰技术,使功放在保证工作效率的同时更大程度提高其线性度。实验结果显示,该方法较传统的线性化技术有明显优势,功放输出信号的ACPR可改善20.66 dB。     

X波段85W功率放大模块微带电路设计

针对X波段50 W GaN功放管电路进行改进设计,在满足原有指标的条件下,同时提高电路工作稳定性;巧妙改变微波电路结构,去除了原电路所用的电感,并在不影响电路指标的前提下适当减少了电容、电阻的用量,为整个电路的设计节约了成本。同时,仿真并制作了Wilkinson功分功合器。最终得到85 W功率放大模块,并给出了测试结果。     

The prediction of transport parameters in filamentous fermentation broths based on results obtained in pseudoplastic polymer solutions

Transport phenomena studies on single phase “model” fluids are of limited value in biochemical engineering if they cannot be translated to the heterogeneous systems encountered in real fermentation processes. In this paper we discuss the utility of polymer solutions as models of filamentous fermentation broths for evaluation of: pipeline friction factors and impeller power numbers (turbine and helical ribbon). To a first approximation, polymer solutions can serve as suitable models for the prediction of laminar flow pressure drop in pipelines and turbulent power consumption in stirred tanks. However, results obtained on polymer solutions do not directly apply to filamentous fermentation broths for predictions of laminar flow impeller power consumption and the transition point for turbulent flow in stirred tanks. These discrepancies are believed to result from the existence of a time dependent yield stress in filamentous fermentation broths.     

An exploratory study of buyers’ participation intentions in reputation systems: The relationship quality perspective

Drawing upon a relationship quality framework, this study identifies how satisfaction, trust and different styles of handling conflict influence online buyers’ participation intentions in reputation systems associated with a C2C online shopping platform. Furthermore, we investigate how these effects are moderated by social conformity and the perceived value of knowledge. The results of a survey of 269 online buyers indicate that satisfaction, trust and an accommodating conflict handling style positively impact the intention to submit positive ratings, whereas an avoiding conflict handling style negatively affects the intention to submit positive ratings. Implications and suggestions for future research are provided.     

湿式氨法脱硫工艺及应用

随着二氧化硫对环境的污染越来越严重,国家环保总局对烟气二氧化硫排放控制严格,烟气脱硫显得日益重要。简单介绍了湿式氨法烟气脱硫技术的工艺流程及实际应用情况。湿式氨法脱硫工艺具有原料易得、脱硫塔不易结垢、不产生废水、副产品硫酸铵可作为农用肥料,减少了对环境的二次污染等特点,是较适合我国国情的烟气脱硫技术。     

我国轮胎产业的状况与展望

着重叙述了我国轮胎产业规模与结构,十大名牌企业代表我国轮胎业最好水平,国内企业形式是国有、国有控股、民营、台资、外资各种形式并存.提出我国企业应形成合理的经济规模,才能实现更大的效益增长.我国轮胎产量逐年提高,子午化率也提高较快.轮胎品质还有待提高,应增强自主开发能力.轮胎的进口价格远高于我国轮胎出口价格,指出只有不断创新,才能使我国成为轮胎出口强国.只要轮胎企业抓住机遇,未来的中国轮胎业将会有更广淘的发展空间.     

铁电薄膜存储器底电极Pt/Ti的制备及性能研究

应用射频磁控溅射方法 ,在Si基片上采用不同的溅射工艺制备了铁电薄膜底电极Pt/Ti,并分析了在不同温度下退火后材料的电导率性能和粘结力性能 ,从理论和实验上分析了不同的溅射工艺和退火处理对底电极性能的影响。     

Pressure drop for single and two‐phase flow of non‐newtonian liquids in helical coils

New experimental results on pressure loss for the single and two‐phase gas‐liquid flow with non‐Newtonian liquids in helical coils are reported. For a constant value of the curvature ratio, the value of the helix angle of the coils is varied from 2.56° to 9.37°. For single phase flow, the effect of helix angle on pressure loss is found to be negligible in laminar flow regime but pressure loss increases with the increasing value of helix angle in turbulent flow conditions. On the other hand, for the two‐phase flow, the well‐known Lockhart‐Martinelli method correlates the present results for all values of helix angle (2.56‐9.37°) satisfactorily under turbulent/laminar and turbulent/turbulent conditions over the following ranges of variables as: 0.57 ≤ n′ ≤ 1; Re′ < 4000; Re_l < 4000; Re_g < 8000; 8 ≤ x ≤ 1000 and 0.2 ≤ De′ ≤ 1000.     

Potential of microbial growth control in water hydraulic systems by UV‐irradiation and filtration

Water hydraulic systems use water as a pressure medium and, thus, do not pose such adverse environmental impacts as oil hydraulics. Microbial deterioration of the pressure medium and biofouling of the surfaces restrict the applicability of the water‐based technology. The potential of microbial growth control by UV‐irradiation and filtration was studied in a pilot‐scale water hydraulic system. The UV‐irradiation (25 m Ws cm^?2) of the pressure medium reduced the total viable counts of bacteria by 1–2 log₁₀ cfu cm^?3, whereas the total microbial cell numbers and the numbers of surface‐attached microorganisms remained unaffected. Prefiltration (1.2 µm, absolute) of the pressure medium decreased the total microbial cell number in the water phase and retarded the attachment of bacteria. The filtration during the operation (2 µm, absolute) decreased the total numbers of microbial cells and the total viable counts in the pressure medium, and microbial attachment on the surfaces. Microbial attachment was not prevented by filtration. The microbial water quality obtained by pre‐ and on‐line filtration of the pressure medium was sufficient to ensure the long‐term operation of the water hydraulic system assuming that clean work practices are complied with in assembly and during the operation. © 2002 Society of Chemical Industry