包装处理对杨梅冷藏保鲜效果的影响

在冷藏条件下,采用L9(34)试验,以杨梅发霉率、好果率、硬度、可溶性固形物和总酸含量组成的综合评分为指标,考察了保鲜膜种类、抑菌剂配方、简易气调处理和封口方式等包装处理对杨梅贮藏品质的影响。结果表明:冷藏前合理的组合包装处理能延缓杨梅果实的衰老。影响杨梅贮藏品质的重要因子次序为:封口方式>气调处理>抑菌剂>薄膜,优化组合为使用1号抑菌剂、抽气气调和简单扎口处理。方差分析结果表明:抑菌剂、气调处理和封口方式对杨梅的保鲜效果均达到显著或极显著水平。多重比较结果表明:1号抑菌剂对杨梅的保鲜效果显著好于2号(p<0.05)和3号(p<0.01),抽气气调极显著地优于常规和充氮(p<0.01),松驰扎口的保鲜效果极显著地优于紧扎和热封封口(p<0.01)。     

A S-BAND 2.5 MW HIGH POWER BROADBAND KLYSTRON

In this paper,the design considerations of a high-efficiency high-gain broadband klystron aredescribed.Its buncher has been studied by using small signal gain and large signal efficiencyprograms.With small gain greater than 50dB,the buncher bandwidths of 10% and 10—15% can beobtained for 7 and 8 cavity klystrons respectively.The design methods and measured results ofoutput circuits of two types are introduced.The bandwidths of the filter type and the overlappingmode two gap cavity output circuits are about 7.5—10% and 10—12% respectively.Two types ofS-band broadband klystrons with the two respective output circuits described are constructed andtested,and the one with the former output circuit has 1dB equi-drive bandwidth of 7.5% with anefficiency of 38% and a gain of 43 dB,while the other with the later output circuit has 1dB equi-drive bandwidth of 10%.Their output power is greater than 2.5 MW.     

扇调管一种新型高效率微波管

扇调管(扇形电子束偏转调制管)是在偏调管(gyrocon)基础上发展起来的一种高效率微波管。木文分析了偏调管的基本原理及其限制,指出改善偏调管的性能必须提高其线路效率。本文论述了提高导流系数是其关键之一,从而引出了扇形束的设想以减弱空间电荷效应,并提出了使普通圆柱形电子束变成扁平的扇形束的基本概念和结构。最后给出了对具体结构进行数值计算的结果,表明以上设想是可行的。     

S波段2.5MW宽频带大功率速调管的研制

本文讨论了大功率、高增益、宽频带大功率速调管的设计和制造,还采用小信号增益和大信号效率计算程序,对宽频带速调管的群聚段进行了设计。当小信号增益大于50dB时,7腔速调管的群聚频宽宽于10％,8腔速调管的群聚频宽可达1015％ 给出了两类宽频带输出电路,即滤波器型输出电路和重叠模双间隙腔输出电路的设计方法和测试结果,结果表明:前一种输出电路的频宽可达7.510％,后一种输出电路的频宽可达1015％。 研制了两种类型速调管,采用滤波器型输出段的速调管的性能达到:1dB等激励频宽为7.5％,效率为38％,饱和增益大于43dB,输出功率大于2.5MW。采用双间隙腔输出段的速调管的1dB等激励频宽迟10％,工作稳定。     

10%带宽兆瓦级速调管放大器

正 长期以来,人们对雷达发射机用的兆瓦级末级发射管的效率-带宽特性和增益-带宽特性一直很感兴趣。而且雷达对发射管相位-频率线性,增益平坦性和功率幅值平坦性的要求也越来越高。但是目前微波管产品中,尚没有在这样的功率电平下带宽宽于10％的管子。由于速调管在大功率、高增益、高效率等方面与其他微波管相比,仍占有较大的优势,因此,近十几年来,国际上许多微波管公司,厂家在展宽速调管带宽方面仍进行着不少具有实际意义的研究工作     

SECMOTRON A NEW KIND OF HIGH EFFICIENT MICROWAVE TUBE

Secmotron(sector beam deflection modulation tube)is a new kind of high efficientmicrowave tube which is developed on the basis of gyrocon,The principle of gyrocon has beenanalyzed and it manifests that to increase circuit efficiency is necessary for improving the proper-ties of gyrocon.One of the key points is to increase its perveance.An idea about sector beam isproposed to reduce the effect of space charge.Also the concept and construction of transforminga column beam to a thin sector beam are presented.The numerical calculation of some specificstructure demonstrates that the above idea is realizable.