二硫化钨的生产现状及发展对策

综述了新型的二硫化钨产品主要状况。其内容包括该产品的生产原料，生产工艺及主要设备，产品的特性，应用及市场，产品的发展前景及对策，并讨论了一些问题。     

中铝河南分公司首次实现氧化镓批量销售

近日，中铝河南分公司镓产品的开发和生产取得新进展．在成功开发了荧光氧化镓、医用氯化镓材料等产品的基础上，生产工艺进一步优化，产品纯度不断提升．首次实现了氧化镓产品的批量销售，预计年内该分公司氧化镓的生产能力将初具规模。近年来，中铝河南分公司一方面不断加强质量攻关，优化生产工艺，镓产品回收率及生产能力都有了较大幅度的提高；另一方面，加强与客户沟通，深入了解市场形势和行情，确定产品定位。     

CSP产品屈强比影响因素分析研究

本统计分析了CSP产品厚度(总压下率)、化学成分、过程温度与屈强比的关系，找出了影响产品屈强比的主要影响因素，并提出了降低CSP产品屈强比，改善产品冷成型性能的有效措施。     

青山控股即将推出Φ30—55规格的不锈钢元钢产品

随着市场变化正在不断创新，为满足不同的钢管产品消费需求，青山控股集团旗下成功试制了规格Φ30-55的元钢产品，计划在年底年或明年初正式推出，这标志着青山集团的元钢产品在品种规格上又有了新突破，同时也表明青山的元钢产品市场竞争力有了进一步的增强。     

工程机械产品创新方法探讨

在激烈竞争的国际工程机械行业占有一席之地，必须加强产品创新，加速实现主导产品的机电液一体化，增加产品的技术含量，开发出具有国际领先水平的高附加值产品。产品创新设计必须紧紧围绕产品上市时间、产品质量、产品成本及服务来开展。本文在产品创新方法方面进行了一些探讨。     

大力开发高附加值产品,增强国际市场竞争力

简要介绍了宝钢炼钢厂的工艺流程和主要产品，详细阐述了宝钢高技术的含量，高附加值产品的开发和生产现状，指出了宝钢炼钢在开发高附加值产品中的不足以及今后的工作。     

A081J产品薄板装焊质量控制

一、概述。2002年工厂承接了A081J产品的制造任务，为了达到产品质量的要求，全厂从上到下对该产品的建造质量极为重视。工厂还特别成立了产品办公室，专门负责解决该产品建造过程中的各种问题。     

建立于web的产品售后服务研究

本文提出一种基于web的产品售后服务模型，论述了产品档案，产品售后服务故障识别及处理，借助知识库，层次分析决策法对用户进行服务。     

“八五”期间甘肃省冶金工业主要产品质量分析”

“八五”期间，在党的“改革、开放、搞活”的方针指引下，甘肃冶金工业把转换企业经营机制、调整产品结构、提高产品质量、增加经济效益作为发展方向，建成了一批大中型项目，开发了一批新产品。企业的工艺、装备水平得到加强，产品结构得到优化。这些举措提高了产品的质量水平，降低了原料消耗，主要技术指标有所提高，部分产品填补了我省及西北地区空白，这为甘肃省及冶金工业的进一步发展打下了良好的基础。“八五”末，我省冶金工业产品由“七五”末的12大类38个品种增加到14大类47个品种。新增的产品有焊条钢盘条，拉丝钢盘条，中、高…     

中国钼工业产品组合策略探讨

以产品概念为基础，以产品的分类，产品的组合、产品线等方面简述现代企业产品的合理组合。并结合中国钼业的实际情况进行了企业综合竞争力的分析。对现代企业产品的组合策略进行了初步研究。     

Failure Resistance of Historic Stone Bridge Structure of Charles Bridge. II: Susceptibility to Floods

The paper is a follow-up to the first part devoted to an analogical problem investigated with a view to the degradation of the stone structure due to the effects of nonstress load, and it deals with the probability problem of the bridge structure collapse under the effect of an extreme flood wave. The paper presents the results of the numerical analysis of the response of the historic stone bridge structure of Charles Bridge of the 14th century to the flood wave effect simulated by angular rotation, subsidence, and shifting in the footing bottom of a bridge pier. Special focus is on the effect of interventions into the stone bridge structure dating back to the last major overhaul of 1967–1975, particularly, on the effect of the reinforced concrete slab (tie plate) connecting the opposite bridge breast walls increasing the rigidity of the breast walls and their structurally efficient connection to the vaults of the bridge arches. The numerical analyses performed point out the prevailing negative effects of the implemented interventions in terms of structural rigidity of the stone bridge structure exposed to the effect of a flood wave.     

Addition of Cobalt to Lead Anodes Used for Oxygen Evolution—A Literature Review

A review of the literature dealing with the effect of cobalt on lead-based anodes for oxygen evolution during electrolysis of sulfuric acid solutions verifies that the presence of cobalt at the anode–electrolyte interface, either as constituent of the anode material or as ions in the electrolyte, catalyzes the evolution of oxygen and reduces the corrosion of the anodes and the contamination by lead of metal cathodes produced during electrowinning. However, due to harmful effects of cobalt ions on the cathodic reaction in some processes, these benefits are limited to the electrowinning of copper. Efforts to develop a way of introducing cobalt at the anode–electrolyte interface without interfering with the cathodic reactions are reviewed in this paper. The use of lead–cobalt alloy anodes has had limited success due to issues arising from the low solubility of cobalt in lead, segregation during casting of the alloys, and nonuniform distribution of cobalt which affects the integrity of the anodes. This has been overcome in part lately by inclusion of cobalt into only the surface layer of a lead or lead alloy substrate, by thermal treatment of a cobalt salt to form a catalytic cobalt oxide surface species, or by electrodeposition of composite lead–cobalt oxide anodes. The last approach in particular has been actively investigated by several groups, but to our knowledge it is yet to find application in the industry. The review also critically examines the likely reaction mechanisms involved.     

Reliability-Based Optimal Design of Truss Structures Using Particle Swarm Optimization

In this work, the particle swarm optimization method is employed for the reliability-based optimal design of statically determinate truss structures. Particle swarm optimization is inspired by the social behavior of flocks (swarms) of birds and insects (particles). Every particle’s position represents a specific design. The algorithm searches the design space by adjusting the trajectories of the particles that comprise the swarm. These particles are attracted toward the positions of both their personal best solution and the best solution of the swarm in a stochastic manner. In typical structural optimization problems, safety is dealt with in a yes/no manner fulfilling the set of requirements imposed by codes of practice. Considering uncertainty for the problem parameters offers a measure to quantify safety. This measure provides a rational basis for the estimation of the reliability of the components and of the entire system. Incorporating the reliability into the structural optimization framework one can seek a reliability-based optimal design. For the problems examined herein, the reliability indexes of the structural elements are obtained from analytical expressions. The structure is subsequently analyzed as a series system of correlated elements and the Ditlevsen bounds are used for the calculation of its reliability index. The uncertain-random parameters considered in this work are the load, the yield-critical stress; and the cross sections of the elements. The considered design variables of the optimization problem are the cross-sectional areas of the groups, which control the size of the truss, and the heights and lengths that control the shape of the truss. The results of the optimization are presented for a 25-bar truss and a 30-bar arch and the robustness of the optimization scheme is discussed.     

New Orleans Levee System Performance during Hurricane Katrina: London Avenue and Orleans Canal South

Hurricane Katrina was one of the worst natural disasters in U.S. history. The effects of the hurricane were particularly devastating in the city of New Orleans. Most of the damage was due to the failure of the levee system that surrounds the city to protect it from flooding. This paper presents the results of centrifuge models conducted at Rensselaer Polytechnic Institute and the U.S. Army Corps of Engineers simulating the behavior of the levees at London Avenue North and South that failed during Hurricane Katrina. Those levees failed without being overtopped by the storm surge. Also included are the results of a centrifuge model of one levee section at Orleans Canal South, which did not fail during the hurricane. The key factor of the failure mechanism of the London Avenue levees was the formation of a gap between the flooded side of the levee and the sheetpile. This gap triggered a reduction of the strength at the foundation of the protected side of the levee. The results are fully consistent with field observations.     

Effect of Upward Seepage on Scour and Flow Downstream of an Apron due to Submerged Jets

The upward seepage through the bed sediment downstream of an apron of a sluice gate structure is a common occurrence due to afflux of the flow level between the upstream and downstream reaches of a sluice gate. The result of an experimental investigation on the characteristics of the scour hole and the flow-field downstream of an apron due to submerged jets under the influence of upward seepage through the bed sediment is presented. Experiments were run for the conditions of submerged jets, having submergence factors from 0.99 to 1.72 and jet Froude numbers from 3.15 to 4.87, over beds of sediments (median sizes = 0.8, 1.86, and 3?mm) downstream of an apron under upward seepage velocities. The characteristic lengths of the scour hole determined from the scour profiles are: the maximum equilibrium scour depth, the horizontal distance of the location of maximum scour depth from the edge of the apron, the horizontal extent of the scour hole from the edge of the apron, the dune height, and the horizontal distance of the dune crest from the edge of the apron, all of which were found to increase with an increase in the seepage velocity. Using experimental results, the time variation of the scour depth is scaled by an exponential law, where the nondimensional time scale decreases linearly with an increase in the ratio of the seepage velocity to the issuing jet velocity. The flow field in the submerged jets over both the apron and within the scour hole was detected using an acoustic Doppler velocimeter. The vertical distributions of time-averaged velocities, turbulence intensities and Reynolds stress at different streamwise distances, and the horizontal distribution of bed-shear stress are plotted for the conditions of scour holes with and without upward seepage. Vector plots of the flow field show that the rate of decay of the submerged jet decreases with an increase in the seepage velocity. The flow characteristics in the scour holes are analyzed in the context of the influence of upward seepage velocity on the decay of the velocity and turbulence intensities and the growth of the boundary layer.     

Reliability-Based Design for External Stability of Mechanically Stabilized Earth Walls

A two-phase approach was used to develop a reliability-based design (RBD) method for external stability of mechanically stabilized earth (MSE) walls. In the first phase, a parametric study was conducted using Monte Carlo simulation to identify parameters that affect the probability of external failure of MSE walls. Three modes of failure were considered: sliding, overturning, and bearing capacity. External stability was assessed by treating the reinforced soil as a rigid mass using the same procedures employed for conventional gravity-type wall systems. Results from the parametric study indicate that the mean and coefficient of variation of the backfill friction angle are significant for sliding, the mean and coefficient of variation of the friction angle of the backfill and coefficient of variation of the unit weight of the backfill are significant for overturning, and the mean and coefficient of variation of the friction angle of the foundation soil and the mean of the backfill friction angle are significant for bearing capacity. In the second phase, a series of additional simulations was conducted where the significant parameters identified in the parametric study were varied over a broad range. Results of these simulations were used to develop a set of RBD charts for external stability of MSE walls. A comparison indicates that similar reinforcement lengths are obtained using RBD and conventional methods and that the inherent probability of external failure in conventional deterministic design is ? 0.001. This probability of external failure is similar to inherent probability of failure reported by other investigators for similar geotechnical structures.     

Artificial Ground Freezing of Fully Saturated Soil: Viscoelastic Behavior

The transport and mechanical properties of saturated soil drastically change when temperatures drop below the freezing temperature of water. During artificial ground freezing, this change of properties is exploited in order to minimize deformations during construction work and for groundwater control. Whereas for the latter only the size of the frozen-soil body is relevant, which is obtained by solving the thermal problem, the design of the ground-freezing work for support purposes requires information about the mechanical behavior of frozen soil. In addition to the quantification of the improvement of mechanical properties during freezing, information about the dilation associated with the 9% volume increase of water during freezing is required in order to assess the risk of damage to surface infrastructure caused by frost heave. In this paper, a micromechanics-based model for the prediction of both the aforementioned phase-change dilation and the elastic and viscous properties of freezing saturated soil is presented. Hereby, the macroscopic material behavior is related to the behavior of the different constituents such as soil particles, water, and ice. Combined with the solution of the thermal problem, the proposed model provides the basis for predictions of the performance of support structures composed of frozen soil.     

Pseudostatic Coefficient for Use in Simplified Seismic Slope Stability Evaluation

Pseudostatic slope stability procedures are commonly used in engineering practice. However, the selection of the seismic coefficient employed in the analysis is often based on precedence without due consideration of the amount of seismic displacement that constitutes satisfactory performance for each particular project and without incorporating the vastly different seismic exposure for sites around the world. In this Note, a rational basis for selecting the seismic coefficient is presented. The proposed procedure requires that the engineer establishes the project-specific allowable level of seismic displacement. The seismic response characteristics of the slope are represented by the fundamental period of the potential sliding mass, and the site-dependent seismic demand is characterized by the 5% damped elastic design spectral acceleration at the degraded period of the potential sliding mass. The level of uncertainty in the estimates of the seismic demand and displacement can be handled through the use of different percentile estimates of these values. With the proposed equations, the engineer can properly incorporate the amount of seismic displacement judged to be allowable and the seismic hazard at the site in the selection of the seismic coefficient.     

Influence of Precipitates on Hydraulic Performance of Permeable Reactive Barrier Filters

A study was conducted to elaborate a predictive model that deals with the hydraulic conductivity reduction of permeable reactive barriers (PRBs) used for the in situ treatment of contaminated groundwater. As PRBs are composed of reactive and permeable filters through which the contaminated groundwater flows, their longevity has to be studied from both hydraulic and chemical points of view. Therefore, one-dimensional (1D) column filtration experiments were performed at a pilot scale, and an integrated model based on the solution of the advection-reaction-dispersion (ARD) mass balance equation was developed to study the space and time evolution of the hydraulic conductivity. This model uses the well-known Kozeny-Carman relation, which considers that permeability depends on the porosity and specific surface of the porous media. The ARD equation is solved by using the PHREEQC software with numerous capacities on the chemical point of view. Thanks to specific assumptions on the geometry of the precipitations, by using the floating-spheres model and the introduction of the “balanced time principle,” the evolution of the profiles of conductivity are computed and compared with those deducted from differential pressure measurements in the laboratory. Results of numerical simulations conducted with the model show that the largest porosity reductions occur on a 10-cm-thick layer at the entrance of the PRB as a result of precipitation of calcite minerals (prefilter).     

采场充填料浆流动与离析规律的试验研究

为研究采场充填料浆流动规律及充填料浆离析分层对充填体强度的影响规律,开展了充填料浆流动相似模拟试验及采场原位充填体力学强度测试试验,研究结果表明：单点下料时充填料浆流动终态坡面趋向于正态分布。流动过程中充填料浆产生离析分层现象,主要表现为充填体物料的粒径沿料浆流动方向呈先增大后减小的趋势,充填体强度沿料浆流动方向呈先减小后增大再减小的倒转“S”形趋势。采场原位充填体强度在下料口附近与标准试块强度接近,在采场中间位置附近的充填体强度最小,在距离下料点采场长度7/10左右的位置充填体强度达到最大值。研究成果能够为充填采场下料管的数量及位置设计提供依据,从而保证充填体的整体质量。