Effects of rare earth on inclusions and corrosion resistance of 10PCuRE weathering steel

The types,morphologies and distributions of nonmetallic inclusions in Cu-P weathering steels with and without rare earth were analyzed through a quantitative image analyzer,scanning electron microscopy(SEM)and energy dispersive spectroscopy(EDS)attached to SEM.Solid-soluble content of rare earth in the steels was analyzed by non-aqua electroanalysis and ICP.The results showed that rare earth modified the types and the morphologies of inclusions in the weathering steels.The small spherical rare earth oxysulfides and rare earth sulphides replaced the elongated MnS inclusions in the RE weathering steels.The rare earth inclusions dispersedly distributed and most inclusions were smaller than 2 μm in size.The optimum content of RE was 0.0065%-0.016% for 10PCuRE weathering steels containing about0.002% oxygen and 0.004% sulfur.Solid-soluble content of rare earth in steels was(14-20)x 10-6,which can act as a micro-alloying element.The corrosion resistance of 10PCuRE weathering steels and Q235 were studied by dry-wet cyclic immersion test.Their corrosion rates were obtained respectively.The polarization curves and pitting corrosion behaviors of weathering steels with and without rare earth were measured by electrochemical methods.The corrosion resistance of Cu-P weathering steels was improved by adding an appropriate amount of rare earth.Less and fewer rare earth inclusions largely decreased pitting susceptibility and rate of pit propagation.The pitting potential and the resistance against pitting corrosion of the RE weathering steel were significantly improved due to the modification of rare earth to inclusions.     

Lanthanide NIR luminescence for telecommunications, bioanalyses and solar energy conversion

Present-day advanced technologies heavily rely on the exciting magnetic and spectroscopic properties of lanthanide ions. In particular, their ability to generate well-characterized and intense near-infrared (NIR) luminescence is exploited in any modern fiber-optic telecommunication network. In this feature article, we first summarize the whereabouts underlying the design of highly luminescent NIR molecular edifices and materials. We then focus on describing the main trends in three applications related to this spectral range: telecommunications, biosciences, and solar energy conversion. In telecommunications, efforts concentrate presently on getting easily processable polymer-based waveguide amplifiers. Upconversion nanophosphors emitting in the visible after NIR excitation are now ubiquitous in many bioanalyses while their application to bio-imaging is still in its early stages; however, highly sensitive NIR-NIR systems start to be at hand for both in vitro and in vivo imaging, as well as dual probes combining magnetic resonance and optical imaging. Finally, both silicon-based and dye-sensitized solar cells benefit from the downconversion and upconversion capabilities of lanthanide ions to harvest UV and NIR solar light and to boost the overall quantum efficiency of these next-generation devices.     

Evaluation of D113 cation exchange resin for the removal of Eu(Ⅲ) from aqueous solution

Batch adsorption experiments were conducted for the adsorption of Eu(Ⅲ) ions from aqueous solution by D113 resin. The results indicated that D113 resin could adsorb Eu(Ⅲ) ion effectively from aqueous solution. The adsorption was strongly dependent on pH of the medium with enhanced adsorption as the pH turned from 3.50 to 7.00 and the optimal adsorption condition was in HAc-NaAc medium with pH value of 6.50. The maximum uptake capacity of Eu(Ⅲ) ions was 290.9 mg/g D113 at 298 K, at an initial pH value of 6.50. The overall adsorption process was best described by Lagergren-first-order kinetics. When Freundlich and Langmuir isotherms were tested, the latter had a better fit with the experimental data. The thermodynamic parameters such as free energy (G) which were all negative, indicated that the adsorption of Eu(Ⅲ) ions onto D113 resin was spontaneous and the positive value of enthalpy (H) showed that the adsorption was endothermic in nature. Thomas model was applied to experimental column data to determine the characteristic parameters of column useful for process design. Furthermore, Eu(Ⅲ) could be eluted by using 3.0 mol/L HCl solution and the D113 resin could be regenerated and reused.     

Phase structure and temperature dependent luminescence properties of Sr2LiSiO4F: Eu2+ and Sr2MgSi2O7: Eu2+ phosphors

Green-emitting Sr2LiSiO4F:Eu2+ and blue-emitting Sr2MgSi2O7:Eu2+ phosphors were synthesized by the conventional high temperature solid-state route,respectively.Their structures and photoluminescenee properties were comparatively investigated.It was found that the mixture phases of Sr2MgSi2O7 and SrF2 were obtained when a part of Sr2+ in Sr2LiSiO4F was replaced by some amount of Mg2+ in order to design the possible SrMgLiSiO4F:Eu2+ phosphor.Based on the photoluminescence analysis,Sr2LiSiO4F:Eu2+ phosphor exhibited a green broad emission band of main peak at 513 nm under the excitation of 365 nm,while the Sr2MgSi2O7:Eu2+ and SrMgLiSiO4F:Eu2+ phosphor showed blue emission centered at 467 nm.The temperature dependent photoluminescence properties and room temperature decay time for the three kinds of phosphors were also discussed in this paper.     

Er3+-substituted W-type barium ferrite: preparation and electromagnetic properties

Er3+-substituted W-type barium ferrites Ba1-xErx(Zn0.3Co0.7)2Fe16O27(x=0.00,0.05,0.10,0.15,0.20)were synthesized by polymer adsorbent combustion method.Samples were characterized by X-ray diffraction analysis(XRD),X-ray fluorescence(XRF),scanning electron microscopy(SEM)and network analyzer to investigate the relationships among Er3+concentration,crystal structure,surface mcrphology and electromagnetic properties.All the XRD patterns showed pure phase of W-type barium ferrite when x≤0.15,while the impurity phase of ErFeO3 appeared when x=0.20.The pure W-type barium ferrite showed a hexagonal flake shape.In addition,the microwave electromagnetic properties of samples were analyzed in the frequency range of 2-18 GHz.It was indicated that the electromagnetic properties were significantly improved when Er3+doping content was 0.10.The reasons were also discussed using electromagnetic theory.The optimized ferrite exhibited excellent microwave absoption performance.The maximum of reflection loss(RL)reached about-27.4 dB and RL was below-10dB at the frequency range from 8.4 GHz to 18 GHz,when the thickness was 2.6 mm.     

EXAFS investigation and luminescent properties of nanosized Tb: Lu2O3 phosphors

Nanosized terbium doped Lu2O3 phosphors were synthesized via a modified co-precipitation processing.The as-prepared Tb:Lu2O3 phosphors was consisted of well crystallized nanosized sphere particles with a diameter of about 30 nnx Local structure of Tb ions in Lu2O3 lattice was investigated by an analytical approach based on Fourier transformation of the extended X-ray absorption fine structure(EXAFS) data.X-ray near edge structure (XANES) spectra suggested that all Tb ions doped were tervalonce.EXAFS results indicated that Tb ions have entered the Lu2O3 cubic lattice by means of solid solution.The coordination number and first shell Tb-O distance dropped with the increasing of Tb concentration.Emission spectra of the phosphors was shown to be typical for Tb3+ with main components at 542,550 and 490 nm,derived from irradiative relaxation of 5D4 level.The emission intensity decreased severely with the increasing of Tb concentration from 1 mol.% to 15 tool.%,suggesting a significant concentration quenching above 1 mol.% Tb.The reduction of emission intensity was interpreted by higher distortion derived relaxation among the surface state resident Tb3+ ions.     

Multi-Pass Simulation of Heavy Plate Rolling Including Intermediate Forced Cooling

Thermomechanical Controlled Processing (TMCP) including accelerated cooling after the final hot rolling pass is a well-established technology,widely applied in HSLA steel plate production.However,there are still certain limitations,especially for thicker plate.The rolling schedule includes a long holding period (HP) after the roughing stage to allow the temperature to fall sufficiently for optimised TMCP during finishing.Intermediate Forced Cooling (IFC) applied during the HP can increase productivity by decreasing the required hold time,can restrict austenite grain growth,and can also improve the subsequent strain penetration in thick plate with further metallurgical benefits.Multi-pass plane strain compression (PSC) tests have been performed on the thermomechanical compression (TMC) machine at Sheffield University including different severities of IFC.Clearly it is impossible to simulate all aspects of the temperature and strain gradients present in thick plates in laboratory specimens,and most of the tests were conducted at temperatures and strains calculated by Finite Element modelling as relevant to specific positions through the plate thickness.However,some aspects of the gradients were addressed with tests using cold platens.The results have indeed shown that IFC can shorten the HP and reduce austenite grain growth and its variation across thick plate.     

Overview of Particles and Bubbles in Continuously Cast Steel

This paper gives an overview of phenomena associated with particles and bubbles in continuously cast steel. During steel processing from deoxidation to solidification the inclusion population undergoes changes with opportunities of removal. Flotation is an important separation mechanism. Inclusion particles may accumulate in the solidifying strand, thus forming enriched bands, which depend on the type of casting machine. Bubbles are created during inert gas injection. They also change in size, can float out, but also form accumulation bands. The interaction of bubbles and particles is discussed. Internal structure that recently has been observed on the inner surface of bubbles will be reviewed.     

烦恼 快乐 艺术——池莉“人生三部曲”解读

池莉的"人生三部曲"--<烦恼人生>、<不谈爱情>、<太阳出世>诉尽了普普通通的市民烦恼,小说中主人公被柴米油盐、吃喝拉撒、老婆孩子等琐事所烦着,从而构成他们的"烦恼人生".然而池莉通过自己的艺术创作,以积极的人生态度,又让读者体会到生活本身的快乐,"烦恼人生"中包含着"快乐人生".     

属性块在工程图形中的研究与应用

介绍了在工程图形中用属性块标注表面粗糙度的方法.采用属性块不仅能避免大量重复性的工作,还能节省大量的存储空间,具有提高绘图速度、质量,便于修改,资源共享等应用价值.     

Collaborative Planning and Scheduling of Interrelated Design Changes

During the detailed design stage of a building project, a vast amount of mostly interrelated design information is generated and communicated among specialists from several disciplines. Changes in some design information are inevitable due to the iterative nature of the design process. In many cases, when the design of a building component is modified by one discipline, this change affects the design of many related building components that are the responsibility of several other design disciplines. Commitment and resources are needed to accommodate such design changes to maintain compatibility among all the design information. Otherwise, incompatibility errors become embedded in the design information leading to numerous problems during the construction of the project. This paper presents a computer-assisted methodology that helps design managers in planning and scheduling changes with interrelated effects on the design information.     

对展示设计的探讨

展示设计在当今信息时代应用越来越广泛，其实用价值越来越高，设计效果备受社会关注。本文论述了展示设计的基本概念和特性，结合笔者多年设计工作经验和体会提出了展示空间设计的基本原则和在展示环境设计中对功能空间的处理方式，供展示空间设计者在设计工作中借鉴。     

Identifying a Design Management Package to Support Concurrent Design in Building Wafer Fabrication Facilities

Concurrent design is commonly used in building a semiconductor wafer fabrication facilities to shorten projects. Current practice in managing a design schedule involves preset milestones that represent percentages of completion. Such a simple control scheme does not provide sufficient information to support concurrent design. This study presents an analytical model that applies a cluster identification algorithm to separate the work of designing a multisystem project into management packages that support concurrent design. Tasks within a package have strong informational dependency relationships on each other, and are not suited for concurrent design. Tasks of different packages have weak dependency relationships on each other, and are suited for concurrent design. Tendering design work based on these packages may reduce the number of design interfaces between participating design firms. Possible application of the model includes the management of design schedule, design contract tendering, and design information flow.     

Sources of Changes in Design–Build Contracts for a Governmental Owner

In recent years, many U.S. federal, state, and local governments have been authorized to use the design–build method of project delivery instead of the traditional design–bid–build method. Recent studies have not been definitive on the cost advantage of design–build for governmental owners. There are fewer change orders in design–build due to design errors because the designer (architect/engineer) and contractor are one entity, but there are other causes of change orders. Some literature suggests that changes requested by the owner of the facility are greater with the design–build method. This research examines the causes for construction-phase changes in 14 design–build and 20 design–bid–build projects. Total changes, expressed as number per contract, cost per contract, or percentage of original contract, were significantly lower in design–build. Fewer design errors in design–build accounted for this advantage. The number of owner-requested changes was significantly greater in design–build. The cost of owner-requested changes, averaged over all the projects, was significantly less for design–bid–build. The differences in changes due to differing site conditions were not significant. The concept that there are more owner-requested changes in design–build projects is supported by this research.     

浅谈结构设计中的质量管理

本文通过对建筑结构设计前期质量管理,设计过程质量管理,设计后期质量管理的阐述,分析了建筑结构设计全面质量管理的过程,简洁透明、便于掌握。有效地执行建筑结构设计全面质量管理是设计单位在同行业竞争中的关键因素。     

Design Structure Matrix Implementation on a Seismic Retrofit

A void exists in development of design theory methodology within the structural engineering community. This void hampers efforts to resolve performance deficiencies including cost over-runs, unplanned rework, and suboptimal design. In manufacturing, product design and production improvements have resulted from implementation of the design structure matrix (DSM) methodology. DSM offers a means to represent, analyze, and decompose complex systems in order to improve their performance. DSM use within the architecture engineering construction (AEC) industry has been sporadic and focused primarily in the U.K. Where applied, DSM has proven effective at helping AEC design teams streamline processes to address nonlinearity (nonsequential information flows) introduced by iteration and complexity in design. When a DSM reveals iteration and highly dependent work, group brainstorming, collocated design sessions, rapid feedback, set-based design, and collaborative design aids can be used to increase overall team effectiveness. This paper examines a case study where DSM-based planning software was used on a seismic retrofit project to drive process improvement in design management. DSM correctly identified iterative activities central to design and provided the following; (1) a common vocabulary to discuss rework in the context of a multidisciplinary design team; (2) a rational method to schedule team collocation and brainstorming efforts to maximize their benefit; and (3) a means to consider iterative activities (and associated hand-offs) in design work structuring.     

Renovation Projects: Design Process Problems and Improvement Mechanisms

This paper presents a case study of a recent office renovation project. The paper investigates the problems that occurred during the design process, analyzes the causes of design iterations and rework, and proposes changes that can improve the design process. The analysis illustrates two design challenges that cause iterations and rework: (1) preexisting, hidden conditions identified late in the design process, and (2) limitations of downstream systems that were not accounted for in upstream decisions. The recommendations propose mechanisms to reduce design rework and duration, and increase the quality of the design solution. The recommendations are (1) to accelerate the discovery of existing conditions, (2) to identify the project constraints that design and construction have to meet, (3) to select the project team early, and (4) to accelerate the iterative design process with a team-based rapid development of schematic design (rapid prototyping).     

Concept for Type-Local Instance–Global Instance Object Modeling and Application to Structural Design of Buildings

Rational data modeling is prerequisite to the computerization of design, and the use of design information in the subsequent work, in areas such as cost estimation and construction. In particular, the structural design of buildings consists of a long series of unit steps and is nonprocedural and data intensive compared with structural analysis problems that are procedural and computation intensive. Hence, there is a need to investigate the characteristics of the problem and to structure design information properly to effectively manage it in the structural design process. This paper discusses modeling concepts for managing design information efficiently and supporting the design process effectively. Type-local instance–global instance object modeling is the conceptual backbone of the model in this study and provides consistent modeling of structural components including not only primitive members such as beams and columns, but also composite elements such as floors, frames, and even whole buildings. This paper also provides core and extended object concepts for classifying structural design information into an overall design and for processing dependent temporary stages in the design. Foundational and application object concepts are introduced for extending the model to various types of structures. An integrated structural design system for buildings is developed based on these modeling concepts, and finally a brief discussion of the application of the object model throughout the entire structural design process in the integrated structural design system is given. It is expected that the modeling concepts proposed in this research can be applied to a range of other engineering applications.     

阿尔及利亚供水管线项目设计体会

针对阿尔及利亚供水项目,论述了供水项目设计过程中的管道选线、水力计算、管道设计、主体构筑物设计、附属构筑物设计等相关问题,提供了满足技术要求、适合当地市场的供水项目设计经验。     

冶金机械绿色设计应用关键问题研究

绿色设计是冶金机械制造业的发展方向,对绿色设计应用的关键问题进行了分析.针对目前推广应用冶金机械绿色设计出现的问题,介绍了绿色设计的基本原则、方法、关键技术和后评价体系,为相关设计人员提供参考.