Flow influenced electrochemical corrosion of nickel aluminium bronze – Part I. Cathodic polarisation

The cathodic polarisation behaviour of CA 104 nickel aluminium bronze (NAB) has been examined in fully characterised seawaters (filtered and artificial) using the rotating disc electrode (RDE) and the rotating cylinder electrode (RCE). Linear sweep voltammetry and a potential step, current transient technique were used to examine the charge transfer and mass transfer controlled cathodic response as a function of both laminar and turbulent fluid flow. For freshly polished surfaces, the rate of irreversible charge transfer controlled oxygen reduction is controlled by the exchange of a single electron and hydrogen evolution is only significant at potentials more negative than approximately –1.0 V vs. the saturated calomel electrode (SCE).     

Uniform culture in solid-state fermentation with fungi and its efficient enzyme production

Solid-state fermentation (SSF) has attracted a lot of interest for carrying out high-level protein production in filamentous fungi. However, it has problems such as the fermentation heat generated during the culture in addition to the reduced mobility of substances. These conditions lead to a nonuniform state in the culture substrate and result in low reproducibility. We constructed a non-airflow box (NAB) with a moisture permeable fluoropolymer membrane, thereby making it possible to control and maintain uniform and optimal conditions in the substrate. For the NAB culture in Aspergillus oryzae, temperature and water content on/in the whole substrate were more consistent than for a traditional tray box (TB) culture. Total weight after the culture remained constant and dry conditions could be achieved during the culture. These data demonstrate the possibility of growing a uniform culture of the whole substrate for SSF. The NAB is advantageous because it allows for the control of exact temperature and water content in the substrate during the culture by allowing vapor with latent heat to dissipate out of the box. In addition, several enzymes in the NAB culture exhibited higher production levels than in the TB culture. We believe that culturing in the constructed NAB could become a standard technique for commercial SSF.     

Corrosion properties of friction-stir processed cast NiAl bronze

Friction-stir processing (FSP) was adopted to modify the microstructure of a cast Cu-9Al-4.5Ni-4Fe NiAl bronze alloy (NAB). After FSP, the initial coarse microstructure of the cast NAB was transformed to a fine structure, and the porosity defects were eliminated. The microstructure modification changed the corrosion behavior of the NAB in a 3.5% NaCl solution. In a static immersion corrosion test, the FSP NAB exhibited significantly greater corrosion resistance compared to the cast counterpart. The polarization curve and electrochemical impedance spectroscopic (EIS) results indicated that the FSP NAB showed slightly lower electrochemical corrosion resistance.     

新一代的SDV平台

本文主要介绍了BVCOM公司针对广电网的核心业务DVB、VOD、IPTV,于2008底成功推出的新一代SDV平台,文中重点阐述了SDV的创新技术及技术优势,以及公司在借鉴了同行失败及成功的经验基础上,如何突破性扩展了体系应用,真正实现了＂播出、传输、监测、管理＂系统级的解决方案     

硝酸盐、亚硝酸盐和烟碱对卷烟主流烟气中烟草特有N-亚硝胺的影响

研究了卷烟主流烟气中烟草特有N亚硝胺及其前体的相互关系,通过在卷烟烟支中分别加入硝酸盐、亚硝酸盐、烟碱,采用标准方法对烟气总粒相物进行捕集,捕集后的样品进行前处理,采用内标法对烟草特有N亚硝胺(TSNAs)进行气相热能分析仪(GCTEA)定量分析,分别研究了4种烟草特有N亚硝胺(NNN、NAT、NAB、NNK)及其总量与硝酸盐、亚硝酸盐和烟碱的相互关系。研究结果表明:硝酸盐、亚硝酸盐、烟碱均是烟草特有N亚硝胺的重要前体物质,随着这些前体物质含量的增加,卷烟主流烟气中的烟草特有N亚硝胺含量也增加,表现出显著的相关关系。      

镍铝青铜合金(NAB)的研究进展

镍铝青铜(NAB)由于具有较好的机械和耐腐蚀性能,在船舶螺旋桨和泵、阀等部件上有着广泛的应用。进一步提高其在复杂海洋工况下的腐蚀疲劳性能是制造高服役性能海洋装备的核心之一。综述了NAB在显微组织、腐蚀行为、热加工以及表面覆层和改性等方面的研究进展,并提出了在实际应用中的问题和进一步研究的主要方向。     

The corrosion of nickel–aluminium bronze in seawater

Nickel–aluminium bronze (NAB) alloys show good corrosion resistance under marine conditions. The corrosion behaviour of cast and wrought NAB alloys is illustrated in this work through a range of electrochemical techniques including open-circuit potentiometry with time, oxygen reduction voltammetry, NAB dissolution voltammetry, potential step (or flow step) current transients and linear polarisation resistance. The galvanic coupling of NAB to stainless steel or copper is examined by zero resistance ammetery. The importance of using controlled flow working electrodes is illustrated by the use of a rotating disc electrode, a rotating cylinder electrode and a bimetallic (NAB/copper–nickel) rotating cylinder electrode. In addition to controlling the hydrodynamics, such electrodes allow charge transfer data to separate from those of mass transport control under mixed kinetic control. Longer term seawater immersion trials on planar coupons coupled to titanium or cupronickel are also reported. The relative contributions of erosion and corrosion attack are considered using a wall-jet electrode and the corrosion characteristics of NAB are compared to those of copper and copper–nickel in chloride media.     

NAB97展出的数字HDTV发射管

本文主要论述了英国ＥＥＶ，美国ＶａｒｉａｎｓＥｉｍａｃＤｉｖｉｓｉｏｎ和ＷｅｓｔｉｎｇｈｏｕｓｅＥｌｅｃ－ｔｒｉｃＣｏｒｐ．以及法国Ｔｈｏｍｓｏｎ四家公司在ＮＡＢ９７展示的数字ＨＤＴＶ发射管最新产品：四极管，ＭＳＲ：速调管，ＳｉＣ固态器件，ＩＤＴ和双端四极管Ｄｉａｃｒｏｄｅ的主要技术性能，同时也介绍了上述五种ＨＤＴＶ发射管在数字ＨＤＴＶ发射机中的应用实例。