通过期铜规避电缆成本中铜价波动风险及实证分析

合理量的期铜操作能够降低或锁定一段时期电缆生产和库存成本,解决销售、投标过程中因铜价上涨给企业带来的履约困惑,且占用资金不多,是规避因铜价波动给电缆成本带来风险的有效途径之一。本文简述电缆生产企业在期铜市场不同情况操作的一些实战方法。     

XLPE电缆绝缘的热线诊断

过去，对交联聚乙烯（ＸＬＰＥ）电缆的故障诊断采用停电后施加直流耐压来进行，这种方法可能因破坏绝缘而损伤电缆．为此，上海电缆研究所和宝钢合作研制成功一种既能在线诊断，又不损伤电缆绝缘的仪器．文中对该仪器作了介绍．     

3D Coordinating Relations between Steel Cables and Concrete of Prestressed Concrete Beam Bridges

Interaction between steel cables and concrete is complicated in prestressed concrete bridges, especially in curved prestressed concrete bridges. The most significant behavior of curved beam bridges under the loads is that, at the same time of vertical flexure, torsion occurs on the cross section, which complicates the mechanical analysis to curved beam bridges. Based on coordinating relations of steel cables and concrete (CRSC), the grillage structure finite-element method was adopted to analyze the spatial effect of curved beam bridges. This way, the effect of all prestressing procedures can be simulated properly, including the prestressing loss due to concrete shrinkage and creep, batch prestressing of the cables, etc. Furthermore, it is effective to analyze the integrated behavior of the combined steel cables space out and concrete. The efficiency and reliability of the CRSC method is demonstrated by our analysis system WXQ2.0 developed for curved-skew bridges.     

Assembly and function of the actin cytoskeleton of yeast: relationships between cables and patches

Actin in eukaryotic cells is found in different pools, with filaments being organized into a variety of supramolecular assemblies. To investigate the assembly and functional relationships between different parts of the actin cytoskeleton in one cell, we studied the morphology and dynamics of cables and patches in yeast. The fine structure of actin cables and the manner in which cables disassemble support a model in which cables are composed of a number of overlapping actin filaments. No evidence for intrinsic polarity of cables was found. To investigate to what extent different parts of the actin cytoskeleton depend on each other, we looked for relationships between cables and patches. Patches and cables were often associated, and their polarized distributions were highly correlated. Therefore, patches and cables do appear to depend on each other for assembly and function. Many cell types show rearrangements of the actin cytoskeleton, which can occur via assembly or movement of actin filaments. In our studies, dramatic changes in actin polarization did not include changes in filamentous actin. In addition, the concentration of actin patches was relatively constant as cells grew. Therefore, cells do not have bursts of activity in which new parts of the actin cytoskeleton are created.     

Evaluation, Rehabilitation Planning, and Stay-Cable Replacement Design for the Hale Boggs Bridge in Luling, Louisiana

The Hale Boggs Bridge opened to traffic on October 5, 1983. At the time, it was the first U.S. cable-stayed crossing over the Mississippi River. The PE (polyethylene) protective sheathing was damaged in many of the cables before and during installation, and after the opening of the bridge to traffic. Repairs were attempted to correct the defects in cable sheathing. Many of the repairs performed poorly and failed to protect the main tension element. The condition of 39 out of 72 cables indicated a critical need for repair and timely action was recommended. To address these damages, and to assure the structural integrity of the bridge structure, several strategies involving a range of repair and replacement options were evaluated using life cycle cost analysis. It was concluded that the strategy to replace all cables presents the best value among evaluated alternatives. The design of the complete 72 cable array replacement is the first occasion on which this process is attempted in North America. The final design of the replacement cables is heavily influenced by the geometric restrictions of the existing anchorage locations. The replacement cables are being designed for a 75-year design life and incorporated with the latest advancements in corrosion protection and vibration control. Maintenance of traffic design is an essential part of the project. The bridge is a critical regional link and constitutes a hurricane evacuation route. Traffic maintenance during cable replacement was designed to be as unobtrusive to the public and commerce as practical. This paper describes efforts associated with cable condition assessment, rehabilitation strategy, and design considerations and concepts, undertaken by the writers since 2002 to improve the condition of this major river crossing.     

利用通信线远程控制信号机的解决方案

介绍一种利用通信电缆实现信号机远程控制的方案。该方案借鉴铁路信号半自动闭塞电路工作原理，月用既有电话电缆控制3km外的信号机，投资少，经济效益显著。     

Tropomyosin-containing actin cables direct the Myo2p-dependent polarized delivery of secretory vesicles in budding yeast

The actin cytoskeleton in budding yeast consists of cortical patches and cables, both of which polarize toward regions of cell growth. Tropomyosin localizes specifically to actin cables and not cortical patches. Upon shifting cells with conditionally defective tropomyosin to restrictive temperatures, actin cables disappear within 1 min and both the unconventional class V myosin Myo2p and the secretory vesicle-associated Rab GTPase Sec4p depolarize rapidly. Bud growth ceases and the mother cell grows isotropically. When returned to permissive temperatures, tropomyosin-containing cables reform within 1 min in polarized arrays. Cable reassembly permits rapid enrichment of Myo2p at the focus of nascent cables as well as the Myo2p- dependent recruitment of Sec4p and the exocyst protein Sec8p, and the initiation of bud emergence. With the loss of actin cables, cortical patches slowly assume an isotropic distribution within the cell and will repolarize only after restoration of cables. Therefore, actin cables respond to polarity cues independently of the overall distribution of cortical patches and are able to directly target the Myo2p-dependent delivery of secretory vesicles and polarization of growth.     

计算机信息网络的防雷系统改造

计算机中心机房设备多,电源线、通讯线、数据线互相交叉,极易进受感应雷击。通过对洪钢计算机中心机房雷击事故分析,采取了计算机机房的防雷和接地措施,确保了网络的安全。     

Single-channel characterization of the pharmacological properties of the K(Ca2+) channel of intermediate conductance in bovine aortic endothelial cells

The effects of scatter factor, HGF/SF, on multinuclear MDCK epitheliocytes were examined. Multinuclear cells were obtained by blocking cytokinesis by low concentration of cytochalasin D; these large cells had discoid shape and did not move much on the substrate. Incubation of these cells with HGF/SF induced their profound reorganization: their cytoplasm was reversibly segregated into several individually moving motile flattened domains, termed lamelloplasts and connected with one another by cylindrical domains termed cables. One or several nuclei were present in many lamelloplasts, but some lamelloplasts were anuclear. Nuclei were absent from the cables. Lamelloplasts continuously formed actin-rich ruffles at their edges; their cytoplasm contained small actin bundles and numerous focal adhesions. In contrast, cable, had no ruffles or focal adhesions. Dense networks of vimentin and keratin intermediate filaments were present in lamelloplasts; bundles of filaments of both types were seen in the cables. Segregation was accompanied by redistribution of centrosomes from perinuclear zone into lamelloplasts. As a result each lamelloplast in segregated cell acquired individual complex of centrosome and radiating microtubules. The cables contained numerous parallel microtubules but never had centrosomes. This reorganization of microtubular system was essential for segregation as alterations of shape and actin cytoskeleton were prevented by microtubule specific drugs: colcemid and Taxol (paclitaxel). It is suggested that mechanism of segregation is based on activation of two types of opposite actin reorganization: formation of actin networks in lamelloplasts and their dismantlement in the cables. Spatial distribution of the domains in which these opposite types of reorganizations occur may be regulated by microtubular system. It is also suggested that mechanisms of HGF/SF-induced segregation may be closely related to the mechanisms of important physiological reorganizations of cells, such as polarization of pseudopodial activities in motile cells and cytokinesis.     

110 kV变电所输电线路电缆接地方式探索

包钢82#变电所110 kV外网采用110 kV单芯电缆,由于电缆根据实际环境设计过长并且电缆之间距离较近,金属护套产生感应电压,为消除感应电压,在110 kV高压电缆使用护套接地的方式,根据线路的不同情况在护套上不同采用接地的方式,并进行经济比较,采用优化方案保证金属护套在最高电压时对地绝缘正常。     

Monitoring of Steel Railway Floor Beams Prestressed by Steel Plates

Steel cables and tendons are commonly used in reinforcing steel beams as well as in concrete beams. However, the structural detail of cable anchors in steel beams tends to be complicated, and the effect on reducing live load stresses is not significant because of the relatively small stiffness of cables and tendons. On the contrary, by using high strength steel plates instead of cables and tendons, structural detail of the anchor area becomes simpler, and live load stresses as well as dead load stresses can be reduced in steel beams because of the relatively large stiffness of steel plates. In this study, the steel plate prestressing method is applied to beam specimens and intermediate floor beams of a steel railway through girder bridge. The behavior of the reinforcing steel plates and reinforced steel beams is monitored during prestressing and live loading, in order to assess the effects of prestressing and reinforcement. The study confirmed that these effects are beneficial to the performance of steel railway floor beams.     

Number of Cable Effects on Buckling Analysis of Cable-Stayed Bridges

Cables instead of interval piers support cable-stayed bridges, and the bridge deck is subjected to strong axial forces due to the horizontal components of cable reactions. The structural behavior of a bridge deck becomes nonlinear because of the axial forces, large deflection, and nonlinear behavior of the cables and the large deformation of the pylons as well as their interactions. The locations and amplitude of axial forces acting on the bridge deck may depend on the number of cables. Agrawal indicated that the maximum cable tension decreases rapidly with the increase in the number of cables. This paper investigates the stability analysis of cable-stayed bridges and considers cable-stayed bridges with geometry similar to those proposed in Agrawal's paper. A digital computer and numerical analysis are used to examine 2D finite element models of these bridges. The eigen buckling analysis has been applied to find the minimum critical loads of the cable-stayed bridges. The numerical results indicate that the total cumulative axial forces acting on the bridge girder increase as the number of cables increases, yet because the bridge deck is subjected to strong axial forces, the critical load of the bridges decreases. Increasing the number of cables may not increase the critical load on buckling analysis of this type of bridge. The fundamental critical loads increase if the ratio of Ip∕Ib increases until the ratio reaches the optimum ratio. If the ratio of Ip∕Ib is greater than the optimum ratio, depending on the geometry of an individual bridge, the fundamental critical load decreases for all the types of bridges considered in this paper. In order to make the results useful, they have been normalized and represented in graphical form.     

新型梳形电缆防火墙的应用

通过新型梳形电缆防火墙的实施，有效地限制了电缆火灾范围，增强了电缆防火、隔火能力，并详细地介绍了梳形电缆防火墙的原理结构、安装使用和注意事项。     

Inspection and Process of Tension of Cables of General Rafael Urdaneta Bridge

In 1997 and 1999, inspection works were carried out in the 384 cable stays of the six central piers of General Rafael Urdaneta Bridge, located in Maracaibo, Venezuela. Inspection indicated the presence of water and significant settlings in the sockets of the cables and corrosion along each cable and socket. The tension of the cables was also measured, and differences of up to 30% in the tension of the cables of some of the 24 groups corresponding to the six central piers (four groups of 16 for each pier) were found. The results suggested the need to retension the cables. This paper shows the outcome of the inspection and indicates the procedure and results of the process of retension, finished in July 2000.     

长锚索预加固技术在上向水平分层充填采场中的应用

长锚索预加固采场顶板,是抑制开挖工程岩体变形和对失稳岩体进行预加固的有效措施之一。以河西金矿上向水平分层尾砂胶结充填采矿法为工程背景,介绍了钢丝绳（钢绞线）长锚索结构和支护参数,叙述了充填采场长锚索预加固施工工艺过程。充填采场实施长锚索预加固措施后,收到了良好的护顶效果。     

Vibration Control of Stay Cables of the Shandong Binzhou Yellow River Highway Bridge Using Magnetorheological Fluid Dampers

The Shandong Binzhou Yellow River Highway Bridge is a three-tower, cable-stayed bridge in Shandong Province, China. Because the stay cables are prone to vibration, 40 magnetorheological (MR) fluid dampers were attached to the 20 longest cables of this bridge to suppress possible vibration. An innovative control algorithm for active and semiactive control of mass-distributed dynamic systems, e.g., stay cables, was proposed. The frequencies and modal damping ratios of the unimpeded tested cable were identified through an ambient vibration test and free vibration tests, respectively. Subsequently, a series of field tests were carried out to investigate the control efficacy of the free cable vibrations achieved by semiactive MR dampers, “Passive-off” MR dampers and “Passive-on” MR dampers. The first three modal damping ratios of the cable incorporated with the MR dampers were also identified from the in situ experiments. The field experiment results indicated that the semiactive MR dampers can provide significantly greater supplemental damping for the cable than either the Passive-off or the Passive-on MR dampers because of the pseudonegative stiffness generated by the semiactive MR dampers.     

Novel popout with nonsense strings: effects of predictability of string length and spatial location

The implanted system was composed of four silver ball electrodes placed in the burr hole of the skull, a reference placed subcutaneously near the nose, two electrodes for EMG, and a ground. The dural attachment was 0.1 mm in diameter. A cassette connector was placed on the back. Implanted cables between the cassette connector and all electrodes consist of twisted fine wires placed in a silicone tube 0.5 mm in diameter. The implanted electrode system weighed 0.8 g. The outlet cables were of the same materials used for implanted cables and placed in a silicone tube 1.5 mm in diameter. The impedance matching between these cables was successful and assured the minimum contamination of artifacts in the EEG recording of freely moving mice. Long-term (4-5 weeks) recording, thus, became possible without damage to the implanted materials. Monopolar recordings demonstrated the localized paroxysmal discharges during general tonic clonic convulsion in El mice. Several artifacts are presented.     

Isolation System for Vibration Control of Stay Cables

Rain-wind induced cable vibration can cause serious problems in cable-stayed bridges. Externally attached dampers have been used to provide an effective means to suppress the vibration of relatively short stay cables. For very long stay cables, however, such damper systems are rendered ineffective, as the dampers need be attached near the end of the cables for aesthetic reasons. This paper investigates a new stay-cable isolation system to mitigate the cable vibration. The proposed isolation system, which consists of a laminated rubber bearing and an internal damper, may be installed inside of the cable anchorage. A simple analytical model of the cable-damper system is developed first based on the taut string representation of the cable. The response of a cable with the proposed isolation system is obtained and then compared to those of the cable with and without an external passive damper. The proposed stay-cable isolation system is shown to perform better than the optimal passive viscous damper, thereby demonstrating its applicability in large cable-stayed bridges.     

Study of Passive Deck-Flaps Flutter Control System on Full Bridge Model. I: Theory

A passive aerodynamic control method for suppression of the wind-induced instabilities of a very long span bridge is presented in this paper. The control system consists of additional control flaps attached to the edges of the bridge deck. Control flap rotations are governed by prestressed springs and additional cables spanned between the control flaps and an auxiliary transverse beam supported by the main cables of the bridge. The rotational movement of the flaps is used to modify the aerodynamic forces acting on the deck and provides aerodynamic forces on the flaps used to stabilize the bridge. A time-domain formulation of self-excited forces for the whole three-dimensional suspension bridge model is obtained through a rational function approximation of the generalized Theodorsen function and implemented in the FEM formulation. This paper lays the theoretical groundwork for the one that follows.     

Estimation of Tension in Cables with Intermediate Elastic Supports Using Finite-Element Method

Cables with intermediate elastic supports are widely used in bridge engineering, but there is a lack of effective methods for estimating the tensions in these cables. In this paper, an analytical form of the equilibrium equation for a tension bar has been used to provide a shape function to develop a suitable finite-element model for a cable. A program for estimating the tension in cables with intermediate elastic supports has been developed in which the bending stiffness of the cable, the stiffness of the end restraints, and the stiffness of the intermediate supports are taken into account by using this element and MATLAB. The program has been verified by comparison of the results from laboratory experiments. The method has been applied to compute the tension in the tie bars of a concrete-filled steel tube arch bridge. This demonstrates that the cable tension estimated by the present method is suitably accurate.