智利纪行

智利以铜著称,是中国铜业关注的地方.尽管北京与智利首都圣地亚哥的距离是全球各国首都之间最远的两个点,但还是有一批又一批的考察团远渡重洋来到这个神秘的国度. 2008年4月,我随山东方圆集团组成的考察组从北京启程,经过两次转机与航行到达地球另一面的圣地亚哥.这是一次行程长达两万多公里,历时近36个小时,横跨了欧亚大陆、穿越非洲大陆、掠过大西洋、赤道线和南美洲的漫长旅行,再加上智利境内的考察航程,往返的行程累计起来可以绕地球一周了!     

阿基米得螺线系数选择对模拟钛弯管推扩成形的影响

采用MSC公司的Superform软件对不同阿基米得螺线系数下的热推扩进行了模拟.扩径段采用了3种不同的系数并分析了不同系数下对热推扩成形弯管的影响.结果表明:扩径变形段中心轴线采用曲率半径渐变的阿基米得螺线,有利于管坯凹面金属充分向凸面流动,避免了传统弯曲变形内侧受压增厚,外侧受拉减薄;阿基米得螺线系数a≤0.9时,环向厚度差大;a≥l.3时,容易出现起皱和45°剪切变薄.本试验范围内,a值取1.0最佳.     

国外废金属的主要分布区域

国外废金属主要分布在工业发达国家.按产生分布地区划分,大体可分为北美地区(美国、加拿大),欧洲地区(欧共体),东南亚地区(日本、韩国、台湾),俄罗斯及澳洲几大部分.     

调解的精髓在于双赢——中国国际商会调解中心为再生企业排忧解难

1987年,伴随着国际贸易、国际投资和国际经济合作业务的持续增长,各种商事纠纷和贸易摩擦的不断增加,中国贸促会成立了第一家商事调解机构--北京调解中心2000年北京调解中心正式更名为中国贸促会/中国国际商会调解中心. 中国贸促会/中国国际商会调解中心秉承"以和为贵"、"促进双赢"的调解理念,以调解的方式,独立公正地帮助中外当事人解决了大量的商事争议,成为中国商事调解领域一支最重要的社会力量.其现有中外籍在册调解员300 余名,有41家贸促会系统地方调解中心遍布在全国各地,形成了一个庞大的调解网络.整个调解网络的受案量已达 6 000余件,调解成功率达到80%.调解当事人涉及50多个国家和地区.     

梦醒在开始的地方再生产业从风雨迷茫中一路走来

资源再生、循环经济在今天可谓风光无限:国家大力提倡,企业日益重视,再生产业吸引了全社会的目光.但在从新中国成立到改革开放后二十年的时间里,资源再生还是一个没有独立构成的行业,从业人员也往往因为每天与"破烂"为伍而被人看不起.     

2007年中国机床工具行业十大新闻

1. 中央和地方省市主要领导频繁视察机床行业企业,国家为数控机床产业发展创造了空前良好的发展环境. 胡锦涛、吴邦国、温家宝、贾庆林、李长春等党和国家领导人以及辽宁、黑龙江、山东、江苏、云南、湖北、广东、陕西、浙江、天津、重庆等省市主要领导相继视察了机床工具厂和数控系统厂.各级领导频繁视察,为数控机床产业的发展创造了空前良好的发展环境.     

透析营销失败的10大原因

经验主义,没有创新 　　一些企业或个人成功后,总是喜欢用过去的思路经营新的品种.殊不知任何新品都有差异性,他们的消费对象、产品的核心卖点及表现力均是不同的,经验主义很容易使产品销售走弯路,甚至导致营销失败.作为老产品,包装也要常更新,但要沿袭原有的核心记忆点与要素,才能使市场趋于稳定,甚至增长.……     

亚熔盐法回收赤泥

采用亚熔盐法对赤泥中的Al2O3和Na2O的回收进行研究.实验第一步通过采用亚熔盐和添加适量石灰乳液回收赤泥中的Al2O3,使其中Al2O3的含量降至4.19%,Al2O3单程回收率达88%;实验第二步采用低浓度的NaOH溶液对赤泥进行深度脱钠,使得最终赤泥中Al2O3和Na2O的含量分别降到3.88%和1.39%,Al2O3/SiO2和Na2O/ SiO2相应降到0.17和0.06;经过回收Al2O3和Na2O后的终赤泥呈现出表面疏松多孔的颗粒状形貌.本研究在较低温的条件下综合回收赤泥中的Al2O3和Na2O.     

灰铸铁主要元素变量三角试片白口宽度与抗拉强度数学模型的研究

在进行灰铸铁铸造生产时,通过不断采集同一浇包中铁液所浇注的三角试片白口宽度、主要化学成分及所浇注试棒的抗拉强度,在大量试验数据的基础上,逐渐摸索出三角试片白口的宽度和C、Si、Mn含量与其抗拉强度内在数量关系,用数学归纳法得出一个灰铸铁的主要元素C、Si、Mn三因素变量与三角试片白口宽度和抗拉强度的一次回归方程。借助回归方程能迅速地预测强度,指导配料,最大限度的降低铸件的成本。     

“表面工程行业清洁生产及节能减排新技术、新装备交流会”在北京召开

近日,北京表面工程学会在北航新主楼第八报告厅召开了“表面工程行业清洁生产及节能减排新技术、新装备交流会”,学会邀请了北京中如技术有限公司曹建岭高工和北京蓝丽佳美化工科技中心李家柱研究员作学术报告,交流会由北京表面工程学会理事长朱立群教授主持,学会理事及会员代表近40人出席.     

稀释气体对镁熔体在HFC-134a气氛中高温氧化行为的影响

对镁熔体在HFC-134a/空气混合气体中和HFC-134a/CO2混合气体中的氧化行为进行了比较研究.结果发现,镁熔体在这2种混合气体中的氧化行为存在差异,而且这种差异与HFC-134a的浓度有关.当混合气体中HFC-134a浓度较高时,镁熔体在HFC-134a/CO2混合气体中的氧化速度小于HFC-134a/空气混合气体,差别不是很大;然而,当混合气体中HFC-134a浓度较低时,镁熔体在HFC-134a/CO2混合气体中的氧化速度远小于HFC-134a/空气混合气体中的氧化速度.产生差异的原因可能与氧化膜中MgF2和MgO的相对含量有关,也可能与单质的C含量有关.这一结果表明,在HFC-134a浓度保持不变的情况下,把与HFC-134a混合的稀释气体由空气改变为CO2,可提高混合气体的保护效果,尤其是在HFC-134a浓度较低的情况下.     

Korrelation zwischen der beschleunigten Bewitterung im Laboratorium und der Freibewitterung eines kohlenstoffarmen Stahls in Meeresatmosphäre

Correlation between laboratory and weathering tests with a low carbon steel in maritime atmosphere The work presented here shows a possible correlation of the corrosion behaviour of a low carbon steel in maritime atmosphere and in a salt spray chamber. The corrosion tests in maritime atmosphere have been conducted in the open air and in a covered cabin at the coast of the Black Sea over two years. The laboratory corrosion tests have been conducted in a salt spray chamber and had a duration of 70 days. The correlation between laboratory and weathering tests is represented graphically. The chemical composition of the corrosion products is given.     

2A12低H2 S04浓度的硬质阳极氧化膜结构研究

为进一步研究硬质阳极氧化膜的结构和性能,采用自制的试验装置分析了2A12铝合金在低H2SO4浓度中的硬质阳极氧化膜结构.结果表明:在低H2SO4浓度中所生成的氧化膜的膜层结构与高H2SO4浓度中所生成的氧化膜的膜层结构不同,在低H2SO4浓度中得到的氧化膜膜层比高H2SO4浓度中得到的氧化膜膜层致密,疏松程度随H2SO4浓度的增加而增大.在低H2SO4浓度中得到的氧化膜的硬度与膜厚都要高于高H2SO4浓度中所得到的氧化膜的硬度与膜厚,但氧化膜表面粗糙度也较高H2SO4浓度中的大.     

Complex dynamics of magnetic-flux oscillations in bulk lead-doped lanthanum manganite

Magnetic-flux oscillations in a core made from lead-doped lanthanum manganite have been investigated. The core was located in crossed dc and radio-frequency ac magnetic fields. At a sufficiently large amplitude of the rf field, magnetic-flux jumps were observed and regions of ultrasharp oscillations of the magnetic flux appeared, which correspond to a bifurcation of a soft generation of a limit cycle. Flattened segments appeared in the oscillograms. The phenomena observed are qualitatively explained based on an analysis of processes of the dynamic magnetization reversal of the core along a minor hysteresis loop. The nonlinear phenomena, which indicate a complex dynamics of the magnetic-flux oscillations, exist in a moderately conducting ferromagnetic manganite only in a certain range of frequencies of the ac field, where the depth of a skin layer is comparable with the thickness of the core.     

Identifying nanoscale ferrihydrite in Hydrometallurgical residues

The identification of a disordered nanoscale material such as ferrihydrite in a heterogeneous sample environment, as is typically the case in a hydrometallurgical residue, requires a rigorous multifaceted characterization approach. An example of this is the identification of ferrihydrite in paragoethite process residues generated in zinc refining. In a pure-form ferrihydrite, a poorly crystalline iron(III) oxyhydroxide possesses a characteristic powder x-ray diffraction profile consisting of very broad low-intensity reflections. However, in coexistence with crystalline material, the diffraction profile may be masked, lost in the background noise, and easily overlooked. By using several characterization approaches in combination, ferrihydrite can be identified in a hydrometallurgical residue with a higher degree of confidence than can be achieved by the application of a single technique.     

Shear deformation behavior of Al–5% Mg in a semi-solid state

Shear tests have been carried out over a wide temperature range of 753–893 K, including temperatures below and above the solidus temperature, for an Al–5 wt% Mg alloy. The deformation behavior in the semi-solid state is divided into two regions; one is in a semi-solid state containing a discontinuous liquid and the other is in a semi-solid state containing a continuous liquid. An analysis of the activation energy suggests that the deformation in the latter region is associated with the lubricated flow. Deformation in the former region is likely to be a transition from the viscous glide creep in the solid state to the lubricated flow in a semi-solid state containing a continuous liquid.     

The influence of the hydrostatic pressure on the parameters of a pressure wave generated by an electric discharge in a fluid

This study reveals the results of the experimental investigation into the influence of the hydrostatic pressure on the parameters of a pressure wave during an electric discharge in a fluid. It is shown that an increase in the hydrostatic pressure provokes a decrease in the amplitude of the pressure wave and a change in its time profile.     

Effect of low-cycle fatigue on the hot ductility of plain carbon steel

In a continuous casting steelmaking operation, the surface of a slab is under a condition that can be characterized as high-temperature, low-cycle fatigue in which the tensile and compressive stress is repeatedly developed. For this reason, for the evaluation of the hot ductility of a slab, considering the fatigue deformation is more feasible before a tensile or compressive test. In this study, the effects of low-cycle fatigue on the hot ductility of steels with a carbon content of 0.06–0.8 wt.% are investigated at various temperatures. For a carbon content of 0.06%, there were no significant differences between the RA values from a simple tensile test and those from a tensile test after fatigue deformation. The tendency of ductility deterioration with fatigue deformation is evident in 0.1 %C steel, and is due to the deformation-induced ferrite film that forms around the prior austenite grain. Conversely, high carbon steel containing 0.8 %C did not show a recovery of hot ductility in a low temperature region, and the specimen on which the tensile was measured after fatigue showed a higher hot ductility in the low temperature region, which is thought to result from the pearlite refinement effects. As the results obtained in this work showed noticeable differences in the hot ductility of carbon steel through the test conditions, it is suggested that for more accurate data, fatigue deformation be adopted in which the temperature range in an unbending operation is determined in the steelmaking factory.     

Drift of a twisted domain wall (TDW) in perpendicularly magnetized films of uniaxial ferromagnetic materials

Drift motion of a twisted domain wall (TDW) in a strong magnetic field circularly polarized in the plane of a perpendicularly magnetized film is considered. The twisted structure reduces the threshold for the regime of stationary motion of a TDW (on both the velocity of motion and frequency of the rotating field) in comparison with a one-dimensional DW of the Bloch or Néel type. The dependence of the boundary of optimum (from the experimental viewpoint) observation of drift of a TDW in the regime of stationary motion on the ratio of the width of a Bloch line to the thickness of the film has been determined.     

A new optical technique for detection of defects in ferromagnetic materials and components

In this paper, we present the details of a new optical technique to detect the defects present in a ferromagnetic material or component, using a ferrofluid emulsion. This new flux leakage probe consists of monodispersed ferrofluid confined between two thin transparent glass slides or in a cuvette and a white light source for illumination. By employing ferrofluid droplets of suitable size and surfactant concentration, one can qualitatively identify the region where the defect is located in the test specimen by visually observing a color change in the ferrofluid cell, in the vicinity of a crack or defect in the test specimen. The origin of this color change in the back scattering direction is due to Bragg scattering from the droplet chains, formed by the leaked magnetic flux in the presence of a defect. We discuss in detail the procedure, the merits and potential uses of this new technique for non-destructive testing and evaluation (NDT and E) applications.