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.     

WELL-DISPERSED NANODIAMOND AQUEOUS SUSPENSIONS——PREPARATION,PROPERTIES AND APPLICATIONS

1　INTRODUCTIONAsitwassynthesizedundertheconditionofhightemperatureandhighpressure ,andowingtothecommoncharacteristicsoffinedimensionandhighsurfaceenergyofnanoscaledparticles ,nanodiamond (ND )preparedbydetonationexplosioncaneasilyformstrongaggregates WhenNDpowderwasaddedinaqueousmedia ,obviousaggregationandsedimentationcanbeobserved ,whichimpairsitscharacteristicsasananometerparticle ,andthushindereditsapplication Inthiscase ,stabledispersionofNDinaqueousmediaisofgreatimportance[1 4 ] …     

Adsorption and electrical properties of nanodiamond powders in the presence of water vapor

The adsorption of water vapor on nanodiamond (ND) powders of detonation synthesis with various chemical states of the particle surface is investigated. The specific surface, porosity, and isotherms of water-vapor adsorption by ND powders are determined. It is shown that ND surface chlorination leads to a decrease of concentration of the primary adsorption centers determining the amount of water adsorbed. The data on the influence of the water vapor relative pressure on electrical conductivity G and dielectric permeability ? of the powders before and after chemical modification of ND are obtained. The interconnection between the amount of adsorbed water and ND electrical parameters is considered within percolation theory. It is shown that water-vapor adsorption leads to a giant increase in the dielectric permeability value and significant rise of conductivity near percolation threshold.     

Study on mechanical properties of anodised film containing nano-diamond particles

Anodic-composite films containing nano-diamond particles (ND) were prepared on 7000 aluminium alloy using an anodising method. The micro-structures of the film were studied by scanning electron microscopy, energy dispersive X-ray spectroscopy, atomic force microscopy and minitab software (version 16). The results indicate that the micro-hardness and wear resistance of the films were improved using the nano-additive. Thus, the wear loss of the composite (the film anodised in the bath containing of sulphric acid, oxalic acid and 85?g?L^?1 ND) evaluated by dry sliding friction test for 50?000 cycles at room temperature, was 0.4?mg compared to 3?mg in the absence of ND, a 750% improvement. The friction of ND composite anodic films is significantly less than the samples without the added particles. Moreover, the micro-hardness of the composite film reached a maximum value of 770?VHN. The results also show that the mechanical properties of the composite films are mainly dependent on the structure of the oxide films.     

Conductivity of aqueous suspensions of alumosilicates

When studying the electrochemical properties of diluted suspensions of natural and modified bentonite, the correlation between the inductive component of the system’s resistance and the temperature has been established. It confirms the hypothesis on the presence of paramagnetic particles in the system, whose solubility decreases with the growth of the temperature. Active forms of oxygen, as generated in the near-electrode space, can be such particles. It is shown that, in model systems, hydrogen peroxide is formed in this space due to the reversible dissociative adsorption of oxygen on platinum in the presence of a suspension electrode with proton conductivity.     

Floc flotation of marmatite fines in aqueous suspensions induced by butyl xanthate and ammonium dibutyl dithiophosphate

The hydrophobic flocculation of marmatite fines in aqueous suspensions induced by butyl xanthate (KBX) and ammonium dibutyl dithiophosphate (ADD) was investigated using laser particle size analysis, microscopy analysis, electrophoretic light scattering, contact angle measurement and infrared spectroscopy. The studies were performed on single minerals with size ≤20 µm by varying several parameters, including pH, collector concentration and kerosene addition. The results show that the floc flotation closely correlated with the size of flocs and the particle hydrophobicity, but was not lowered with increasing the particle surface charges due to collector adsorption. Under good operating conditions, the floc flotation of marmatite fines as a function of KBX and ADD can all reach floatability over 90%, in comparison with conventional flotation obtaining floatability of about 60%. It also has been found that a small addition of kerosene greatly improved the floc flotation because of the formation of oil films on marmatite particles. The results of FTIR spectra indicate that adsorption of the two collectors onto marmatite were chemical adsorption.     

Electro-Synthesis of Nano-Colloidal PANI/ND Composite for Enhancement of Corrosion-Protection Effect of PANI Coatings

The polyaniline/nanodiamond (PANI/ND) nanocomposite coating was prepared on mild steel via electrochemical polymerization using cyclic voltammetry technique. The ultrasonic irradiation was used for effectively dispersing ND particles in electropolymerization solution. The prepared nanocomposite films were found to be nano-colloidal, and very adherent with low porosity. The corrosion performance of the coatings was investigated in 0.5 M H₂SO₄ solution by electrochemical impedance spectroscopy and polarization methods. The obtained results showed that the presence of ND particles significantly enhanced the corrosion protection performance of the PANI films in 0.5 M H₂SO₄ corrosive medium. X-ray diffraction and FT-IR techniques confirmed the intercalation of the nanoparticles in PANI matrix.     

以环氧树脂为母液的悬浮液的电流变效应

研究了以淀粉，二氧化锡和三氧化铝为分散相颗粒，以非油类的环氧树脂为母液的悬浮液，在交流电场作用下的电流变效应及其影响因素，如电场强度，悬浮液浓度，颗粒粒径等，还研究了漏电流密度及其影响因素，实验表明，以环氧树脂为母液的悬浮液具有明显的电流变效应，非油类的环氧树脂可作为电流变液的母液。     

Column Formation in Suspension Plasma-Sprayed Coatings and Resultant Thermal Properties

The suspension plasma spray (SPS) process was used to produce coatings from yttria-stabilized zirconia (YSZ) powders with median diameters of 15 μm and 80 nm. The powder-ethanol suspensions made with 15-μm diameter YSZ particles formed coatings with microstructures typical of the air plasma spray (APS) process, while suspensions made with 80-nm diameter YSZ powder yielded a coarse columnar microstructure not observed in APS coatings. To explain the formation mechanisms of these different microstructures, a hypothesis is presented which relates the dependence of YSZ droplet flight paths on droplet diameter to variations in deposition behavior. The thermal conductivity (k _th) of columnar SPS coatings was measured as a function of temperature in the as-sprayed condition and after a 50 h, 1200 °C heat treatment. Coatings produced from suspensions containing 80 nm YSZ particles at powder concentrations of 2, 8, and 11 wt.% exhibited significantly different k _th values. These differences are connected to microstructural variations between the SPS coatings produced by the three suspension formulations. Heat treatment increased the k _th of the coatings generated from suspensions containing 2 and 11 wt.% of 80 nm YSZ powder, but this k _th increase was less than has been observed in APS coatings.     

Cavitation technologies for dispergation and homogenization

The results of tests carried out in industrial conditions are presented. They allow one to propose cavitation technologies of dispergation and homogenization for fabricating emulsions and suspensions under the action of ultrasonic, hydrodynamic, and hydroacoustic cavitation. The dispergation regimes were found for materials with various physicochemical properties, including viscous media (natural juices with pulp) and materials with a lamella structure (bentonite). Cavitation effects intensify dispergation processes and allow one to produce materials with submicronic dimension of the particles; this considerably increases the sedimentation period of the suspensions.     

Electrophoretic co-deposition of diamond/borosilicate glass composite coatings

Composite coatings made of diamond powders and borosilicate glass have been deposited on stainless steel substrates by electrophoretic co-deposition. Ethanol and acetone suspensions containing diamond powders of particle size 1-2 μm and borosilicate glass powders of size 0.1-0.5 μm were used. Electrophoretic deposition (EPD) parameters were optimized by a trial-and-error-approach. Microstructures of deposited and sintered coatings were investigated by XRD and SEM analysis. The results show that applied voltages up to 10 V led to thin and incomplete coatings. Voltages higher than 50 V resulted in uneven coatings with uncontrolled thickness and poor uniformity. The best results were achieved using ethanol suspensions. Smooth, uniform and dense coatings with diamond and glass particles distributed uniformly were obtained under applied voltages in the range of 30-50 V and a deposition time of 4 min. The concentration ratio of diamond to borosilicate glass in the composite coatings was in good correlation with the original ratio in suspension, thus control of the coating microstructure and composition is possible. During sintering at 900 °C, the glass particles softened; sintered by viscous flow and spread over the diamond particles surface. Thus a glass layer forms protecting the diamond from oxidization or graphitization and bonding the diamond particles together.