基于AAA服务的协议分析与比较*

介绍了RADIUS,TACACS 和DIAMETER三个提供AAA服务的主要协议的结构,分析其各自特点;根据现在网络的发展对AAA服务的需求,从传输性能、安全性能、漫游代理、主动能力和属性等方面比较、分析RADIUS,TACACS 及 DIAMETER协议的优势与不足.研究和分析了DIAMETER协议不仅能满足现有网络的需求,还能满足未来网络发展的需要,是目前公认的较完善的AAA服务协议.     

HIGH SPEED MILLING OF GRAPHITE ELECTRODE WITH ENDMILL OF SMALL DIAMETER

Graphite becomes the prevailing electrode material in electrical discharging machining (EDM)currently.Orthogonal cutting experiments are carried out to study the characteristics of graph- ite chip formation process.High speed milling experiments are conducted to study tool wear and cutting forces.The results show that depth of cut has great influence on graphite chip formation.The removal process of graphite in high speed milling is the mutual result of cutting and grinding process. Graphite is prone to cause severe abrasion wear to coated carbide endmills due to its high abrasive- ness nature.The major patterns of tool wear are flank wear,rake wear,micro-chipping and breakage. Cutting forces can be reduced by adoption of higher cutting speed,moderate feed per tooth,smaller radial and axial depths of cut,and up cutting.     

Formaldehyde and Benzoquinone Cross-links in Keratin

With the preponderance of low-grade jute and mesta fibres available to the industry, softening of the barky and hard root-ends has become a major need in the batching section of a jute mill. The enzymatic method, developed earlier at the Indian Jute Industries' Research Association to soften and clean the body of low-grade lignocellulosic fibres, has been utilized for the purpose, with some modifications, for the release of adequately clean and split filaments of normal jute. Test results obtained from bulk trials in mills show that enzymatic softening of root-ends leads to the double benefit of using a higher proportion of root-section fibre in the batch and improved performance of the process, especially at the spinning stage. Except for the low-grade white jute (Grade W₅ and below), all other root-end-treated low-grade fibres could be processed without cutting the root-ends and incorporated in higher proportions in the hessian- and sacking-warp batches without any difficulty in spinning. When the root-end treatment was extended to cover all the piled fibres, especially of the low-grade type, the spinning performance of the sacking-weft batch, mainly consisting of soft fibres released from pre-treated line cuttings, was significantly improved. The estimated net cost-saving realized from this enzymatic process, including gains from improved performance in spinning, ranged from Rs 50/- to Rs 100/- (i.e., from about £2.75 to £5.50) per tonne of batch.     

33—A GRAVIMETRIC TECHNIQUE FOR DETERMINING THE MEAN FIBRE DIAMETER OF WOOL

A method is presented for determining the diameter of wool gravimetrically by using fibre snippets instead of full-length fibres. A quantity of the snippets is weighed and then counted with an electronic particle-size analyser (a Coulter Counter). The average length of snippets is obtained by measuring the length of a small random sample. The product of the average snippet length and the number of snippets present in the weighed sample provides an estimate of the total length of the weighed snippets. Hence their mass per unit length can be calculated, and, if the fibre density is known, the r.m.s. diameter can also be determined.

For continuous-filament nylon, the method gives excellent agreement with diameter values obtained by a conventional gravimetric technique. For combed wool, the snippet gravimetric diameter is always less than the projection-microscope diameter, corrected to r.m.s. Some of this difference is attributed to reentries in the wool-fibre surface.     

IP网络业务联合认证技术第1讲 IP网络业务安全认证系统发展现状及相关问题分析

IP网络天然的不安全性促使IP网络业务提供者采用各种安全认证技术来保证其所提供的业务的安全性。本文主要介绍IP网络业务安全认证系统发展情况及存在的相关问题。     

23—STUDIES ON THE NOBLE COMB. PART II: HOLDING POWER AND ITS PRACTICAL APPLICATION

An account is given of a study of the combing performance of the Noble comb in which the slivers emerging from the small and large circles were kept separate. Variations in the temperatures and pin densities of the circles produced changes in the holding power of the large circle of from 50 to 90% and in the ratio A/B of from 2 to 24. The holding power is linearly related to the production rate for a constant punch-sliver weight. By applying the correct holding power, an efficient separation of the short fine ‘down’ from the ‘beard’ hair in karakul wool was effected. Two combed slivers were produced simultaneously and differed in fineness by 9 μm. An appreciable reduction in percentage noil was brought about for karakul wool by reducing the pin density of the small circle.