线缆金属材料在土壤中腐蚀行为研究

采用自然埋藏的研究方法对线缆金属材料铅、铝、涂漆钢带、涂塑钢丝在我国各种酸、中、碱性土壤中埋藏8年及40年的腐蚀试验结果进行分析，总结了金属材料腐蚀的规律及土壤和土壤微生物对金属作用影响因素。     

草甸土中线缆及材料土壤自然埋藏试验

采用在草甸土中进行线缆及材料土壤环境自然埋藏及定期测量土壤环境因素、土壤微生物的方法,研究其腐蚀变化规律及腐蚀原因。结果表明：各种线缆外护套性能保持较好;金属材料土壤腐蚀程度中等偏轻,金属平均腐蚀率随时间变化规律基本遵循方程式C=AT~B;成都草旬土中高含水量、低电阻率、可溶性盐及土壤微生物的活动造成金属的腐蚀。     

沈阳菜园型草甸土中线缆及材料埋藏试验研究

将线缆和材料在沈阳站菜园型草甸土中进行土壤环境自然埋藏及定期测量土壤环境因素和土壤微生物,研究其腐蚀变化规律及腐蚀原因。结果表明:金属材料铝腐蚀严重、穿孔;涂漆钢带腐蚀较重;铅土壤腐蚀较轻,线缆外护套性能保持较好。该站土壤为菜园型草甸土,土壤pH值6.9,呈中性,盐含量也较低,但是该站微生物活动强烈,造成金属的腐蚀。     

大港滨海盐土中线缆及材料埋藏试验研究

将线缆和材料在大港滨海盐土中进行土壤环境自然埋藏及定期测量土壤环境因素和土壤微生物,研究其腐蚀变化规律及腐蚀原因.结果表明：金属材料涂漆钢带腐蚀严重;铝腐蚀较重;铅土壤腐蚀较轻;涂塑钢丝及线缆外护套性能保持较好.该站土壤为滨海盐土,高pH值,高含水率,高含盐量及微生物活动强烈,造成金属的腐蚀.     

铅在酸性土壤中的腐蚀行为研究

采用试件自然埋藏的方法研究了铅护套在酸性土壤中1～8年的腐蚀行为。结果表明,铅呈大面积斑点腐蚀,蚀孔小而深。发现酸性土壤中铅的腐蚀率与腐蚀电位有很好的对应关系。铅的腐蚀与土壤PH值、土壤通气性、土壤盐分及土壤微生物有关。     

铅在酸性土壤中的腐蚀行为研究

采用试件自然埋藏的方法研究了铅护套在酸性土壤中1～8年的腐蚀行为。结果表明,铅呈大面积斑点腐蚀,蚀孔小而深。发现酸性土壤中铅的腐蚀率与腐蚀电位有很好的对应关系。铅的腐蚀与土壤PH值、土壤通气性、土壤盐分及土壤微生物有关。     

铝在中、碱性土壤中的腐蚀行为研究

通过对铝在中、碱性土壤中1～8年自然埋藏试验结果的分析,研究了铝在中、碱性土壤中的腐蚀行为,主要表现为局部斑点腐蚀并伴有穿孔发生。腐蚀原因主要与土壤类型、通气性、Cl^-和SO4^2-含量及微生物有关。     

铝在中、碱性土壤中的腐蚀行为研究

通过对铝在中、碱性土壤中1～8年自然埋藏试验结果的分析,研究了铝在中、碱性土壤中的腐蚀行为,主要表现为局部斑点腐蚀并伴有穿孔发生。腐蚀原因主要与土壤类型、通气性、Cl     

成都草甸土中碳钢、铝、铅的短期腐蚀行为

采用在成都材料土壤腐蚀试验站巾（草甸土）进行碳钢、铝、铅试件短期自然埋藏及定期测量土壤环境因素、土壤微生物方法,研究了碳钢、铝、铅短期埋藏的腐蚀变化规律及腐蚀原因。结果表明：碳钢、铝、铅甲均腐蚀率随时间变化规律基本遵循方程式C=AT^B,成都草甸土中高含水量、低电阻率、可溶性盐及土壤微生物的活动促进了碳钢、铝、铅的腐蚀。     

通信光缆用防雷排流线——镀锌钢丝埋藏试验研究

将通信光缆用防雷排流线——镀锌钢丝在我国部分材料试验站进行土壤环境自然埋藏,定期测量土壤环境因素和土壤微生物含量,研究钢丝的力学性能变化及腐蚀规律。结果表明：土壤对镀锌钢丝的腐蚀较重,土壤的理化性质及微生物活动对其影响很大。     

GEMNET: a generalized, shuffle-exchange-based, regular, scalable,modular, multihop, WDM lightwave network

GEMNET is a generalization of shuffle-exchange networks and it can represent a family of network structures (including ShuffleNet and de Bruijn graph) for an arbitrary number of nodes. GEMNET employs a regular interconnection graph with highly desirable properties such as small nodal degree, simple routing, small diameter, and growth capability (viz. scalability). GEMNET can serve as a logical (virtual), packet-switched, multihop topology which can be employed for constructing the next generation of lightwave networks using wavelength-division multiplexing (WDM). Various properties of GEMNET are studied     

Thermodynamics of copper matte converting: Part III. Steady-state volatilization of Au,Ag, Pb,Zn, Ni,Se, Te,Bi, Sb,and As from slag,matte, and metallic copper

A comprehensive compilation of various thermodynamic data required for a complete analysis of copper matte converting reactions is presented. The data comprise estimated free energies of formation for such gases as SeO, SeS, TeO, TeS, BiO, BiS, SbO, SbS, AsO, and AsS, as well as activity coefficients in dilute copper alloys and vapor pressures of various elements and compounds. The volatilization of minor elements in steady-state reactors comprising gas and several condensed phases is mathematically formulated, and a parameter which governs the volatilization in such reactors is defined and named volatilization constant. The vapor pressures of various volatile species are calculated thermodynamically for the Noranda Process reactor by assuming equilibrium conditions. The volatilization constants of various minor elements are expressed explicitly as functions of oxygen and sulfur activities. Formerly Associate Professor, Department of Metallurgical Engineering, University of Utah, Salt Lake City, UT     

Bits, symbols, bauds, and bandwidth

The use of clear, concise, and unambiguous language in telecommunications engineering is vital to communicate a desired meaning and understanding. Terminology should be based on rigorous engineering principles and traceable to well known and dependable sources. This article deals with four everyday terms commonly encountered in the popular semi-technical press as well as in serious engineering periodicals. The misuse of these and other terms can lead to low-balled cost proposals, court litigation, and patent infringement cases. Imagine how an engineering student can be confused when she/he typically encounters bandwidth measured in bits per second     

Novel planar, square-shaped, dielectric-waveguide, single-, and dual-mode filters

This paper presents a novel concept of a square-shaped dielectric-waveguide resonator, which can easily realize a dielectric-waveguide cross-coupled filter or a dielectric-waveguide dual-mode filter, using the conventional printed circuit board (PCB) process. This planar dielectric-waveguide resonator has a higher Q value than a microstrip resonator. The physical mechanisms of both single- and dual-mode filters are elucidated. Some new coupling structures are developed for undergoing the PCB process. Filter design procedures are detailed. Design curves for the coupling coefficients of internal- and external-coupling structures are determined by full-wave finite-element-method electromagnetic calculations. Measurement results are highly consistent with theory for all trial filters. This study offers an effective means of producing low-cost high-performance planar circuit filters.     

PBX技术.市态.营销.选购

本文介绍了ＰＢＸ交换机的技术及市场需求态势。并提出ＰＢＸ产品的营销要素及其用户在选购时应遵循的原则。     

Dilemmas,uncertainty, risks,and board performance

This paper traces the origins of the words risk, uncertainty, governance and development and argues that a deeper understanding of each allows more effective decision taking in the boardroom. It argues that the role of the board of directors is to balance and rebalance continuously their irresolvable dilemma — ‘how do we drive our enterprise forward while keeping it under prudent control?’ It argues that it is the board’s role to focus on uncertainty, rather than risk, and this requires a different set of intellectual skills from board members to be able to cope with monitoring a range of diverse scenarios. This is crucial for a board to develop stronger ways of both leading their organisation and of ensuring the connectedness of the learning within and between the board and the operational unit’s risk taking. It advocates that to achieve this a board must develop new ways of learning — especially of thinking strategically and becoming more sensitised to the dynamics of their changing external environments. This will take them well beyond the comforts of their specialist managerial disciplines and into the true world of directing. The paper demonstrates the importance of continuous learning in reducing organisational uncertainty and risk. It uses the ‘Learning Board’ process and model as the central processor of both strategic and operational learning to create an annual rhythm for the board’s year.