PLC在转炉风机煤气回收中的应用与研究

介绍转炉一次除尘风机及煤气回收系统中应用的可编程控制器(简称PLC)系统，对系统调试生产过程中遇到的几个问题进行分析与研究，并提出建议和改进方法。     

A new concept of fairness in flow‐aware networking

We demonstrate a new approach to assuring fairness in flow‐aware networking. Standard routine in flow‐aware networking guarantees that each flow receives the same amount of resources. This property can be exploited by dividing a single transmission into a number of flows. We propose and evaluate the per‐user fair packet scheduling mechanism, which ensures fairness among users (not flows). We also compare the new mechanism with the one already known from the literature, which is based on altering the admission control routine. Evaluation shows that the new concept of fairness provides better performance and fair resource distribution regardless of the behavior of users.     

Free amino acid profiles from ‘Pinot noir’ grapes are influenced by vine N-status and sample preparation method

This study examined the impact of extraction method on ammonia, free amino acids, and yeast assimilable nitrogen (YAN) concentrations in ‘Pinot noir’ berries obtained from a vine nutrition study (altered supply of N, P, or K). Berries were either juiced or exhaustively extracted as whole berries prior to analysis. Extracts, compared to juice samples, had a significantly higher level of ammonia–N, assimilable amino acid–N, and YAN. For example, juice YAN values were approximately 50% of extract YAN values, when both were expressed in the same units. Free amino acid profiles and relative concentrations of individual amino acids were different in juice versus extracts, depending on how well the skin fraction was extracted prior to analysis. Lowering N supply reduced free amino acids, with arginine being reduced more than the other 20 free amino acids identified in ‘Pinot noir’ berries. This was true in both juice and extracts. Since berry skin contributed to actual YAN, wineries that determine YAN from mainly the pulp fraction (juice) may underestimate YAN and as a result add more (artificial) N supplement than is required for the healthy fermentation of red winemaking (whole berry fermentations). Extraction procedure should be taken into consideration when comparing grape YAN.     

基于FAN9612的交错BCM PFC关键参数设计

为了进一步提高功率因数校正（PFC）控制器的性能,首先叙述了工作于临界导通模式（BCM）下的单相双重交错并联型Boost PFC的原理;然后对基于FAN9612控制芯片实现双重并联交错BCM PFC的功率限制电路和补偿网络相关参数进行了详细的设计;最后搭建了400 W实验样机,测试了相关波形,对实验结果进行了分析。实验结果表明,通过临界导通控制模式与双重并联交错拓扑相结合,保持了功率开关管零流开通、二极管零流关断无反向恢复电流等优点,并进一步减小了输入纹波,降低了对电磁干扰（EMI）滤波器的要求。     

Influence of phytase and supportive enzymes applied during high gravity mash preparation on the improvement of technological indicators of the alcoholic fermentation process

Phytic acid is one of the compounds that can limit the availability of biogenic substances responsible for the environmental stress response of the yeast. The aim of the study was determining the influence of hydrolysis of the phytic acid complexes in the HG maize mashes on the availability of free amino nitrogen (FAN) released from hydrolyzed proteins and the resulting change in the fermentation activity of the yeast. Prospects for the optimization of the alcoholic fermentation process by combined application of phytase, protease and augmented set of amylolytic enzymes were also assessed. The application of protease phytase resulted in an increase of FAN concentration during subsequent hours of the alcoholic fermentation process which indicated an increased availability of proteins susceptible to hydrolysis. A positive effect of combined application of phytase, protease and amylolytic enzymes (with pullulanase) on technological indicators of the fermentation process was observed. The final ethanol concentration increased by 1% v v⁻¹ and the yield increased by 6 L EtOH 100 kg⁻¹ of starch. The optimization of the mashing process, involving the application of additional enzymes (phytase, pullulanase, protease), improved the yield of fermentation in relation to the theoretical yield to the level of 93%. A combined application of α-amylase, pullulanase, glucoamylase, protease and phytase during HG mashes preparation lowered the concentration of higher alcohols by 450 mg L⁻¹ EtOH, on average, as compared to the control variant. At the same time, the concentration of acetaldehyde in the spirits increased above 480 mg L⁻¹ EtOH.     

基于ZVS平均电流型PFC控制器FAN4822的500W大功率电路

FAN4822是快捷半导体公司为大功率电源应用领域而专门设计描率因数校正（PFC）控制芯片，该芯片功能多，效率高，谐波失真小，并具有欠压锁定，过压保护，峰值电流限制等功能，同时可最大限度地减小EMI电磁干扰，文中介绍了FAN4822的主要特点，引脚功能，内部结构和典型应用电路，最后给出了一个带有效率因数校正的500W电源电路。     

基于控制器FAN7544的32W双管荧光灯电子镇流器

美国飞兆公司推出的FAN7544单片IC,提供简单和高性能电子镇流器控制功能,预热时间、预热频率和运行频率可利用外部阴容元件根据需要设定。在介绍FAN7544主要特点、引脚功能、工作原理的基础上,给出了32W双管荧光灯电子镇流器实际电路。     

多攻击线引起的串扰时延故障的TPG

探讨了一种串扰时延最大化算法,并且利用被修改的FAN算法,生成测试矢量.对于一条敏化通路,利用被修改的FAN算法适当地激活相应的攻击线和受害线,使电路在最恶劣情况下引起最大通路时延,从而实现更有效的时延测试.利用了FAN算法的多路回退和回溯等主要特色,提高了测试生成算法的效率.实验结果表明,沿着任何临界通路传播的受害线相耦合的攻击线被适当地激活,并且可以对一定规模的电路的串扰时延故障进行测试矢量生成.     

低电压低饱和压降的步进电机驱动器FAN8200/FAN8200D及其应用

FAN8200／FAN8200D是美国快捷半导体公司设计生产的低电压低饱和压降单片式步进电机驱动器集成电路。它带有双路H－桥和两个独立的垂直PNP功率管，可用于两相步进电机的驱动系统。文中介绍了FAN8200／FAN8200D的主要特点和引脚功能，给出了一个用于数码相机系统的两通道直流电机的驱动电路。     

APFC在电动汽车无线充电系统中的应用研究

通过对无线充电技术发展现状的分析,制约无线充电技术在电动汽车领域推广的主要因素:一是电能传输效率较传统充电技术具有一定差距;二是大功率无线充电设备的使用给电网带来了谐波污染。该文从源头解决问题,在无线充电系统电能变换的第一级—整流滤波环节,增加了有源功率因数校正(APFC)电路。通过分析其工作原理,设计了基于FAN9673的三级交错并联的Boost电路拓扑结构,并计算了电路的主要参数。实验结果表明,网侧输入端电流跟随输入电压变化且无相位差,网侧功率因数在0.99以上,电能传输效率大于97%,APFC电路的输出电压稳定,系统动态性能好,为无线充电系统中后续电路的供电质量提供可靠保障。