鋁电解工艺的现状

历史資料在第二次世界大战之前,彼施涅公司的鋁厂装备的是3～5万安培的預焙阳极电解槽和2～3万安培的側部导电自焙阳极电解槽。电解槽的技术指标列于表1。     

含硫、氧的球墨铸铁孕育剂

常规的球墨铸铁生产中，铁中能否有硫化物和氧化物作为石墨结晶的核心，取决了原铁水的纯度和添加剂、保持时间和温度以及冶金处理工艺和添加剂。     

W-Ni-Cr系高比重合金

研究了W-Ni-Cr系高比重合金的硬度和机械性能。这些合金的硬度较一般合金高得多(Hv值高达600,而W-Ni-Fe合金的Hv值为310)。该合金系的机械性能,按合金成分可分为截然不同的二类:一类是铬镍比(Cr:Ni)低的——塑性较好,硬度略高;另一类是铬镍比高的——硬度高,抗张强度低,几乎没有塑性。为了解释W-Ni-Cr系合金的这种性质,本文确定了该合金系相图的1250℃截面图,证明了三元σ脆性相的存在。延性-脆性转变界限与有σ相的相区边界相对应。对σ相稳定性的研究表明,不可能用简单的热处理消除σ相。在高硬度的合金中,添加第四组元不能阻止σ相生成。     

Bi-based superconductors fabricated in high magnetic fields

The microstructure and superconducting properties of Bi-2223 superconductor fabricated in high magnetic fields were investigated. The results shows that the Bi-2212 grains with their c-axis parallel to the magnetic field were formed after the partial-melting and solidification in 8 T magnetic field, and transformed into the Bi-2223 grains with c-axis alignment during the further sintering process at 840 ℃ without magnetic field. The conversion of Bi-2212 grains to Bi-2223 grains has the heredity in grain alignment. The mixed structures of the Bi-2223 and the Bi-2212 grains with their c-axis parallel to the magnetic field are formed in samples sintered at 850-855 ℃ in 10 T magnetic field. When sintered in 10 T below 845 ℃, a high proportion of Bi-2223 phase is obtained, however no preferred orientation is observed. The Bi-2223 grains with their c-axis parallel to the axial direction of the vertical tube furnace are formed not only on the surface, but also in the center of the sample sintered at 850 ℃ for 120 h in a 15 ℃/cm temperature gradient without magnetic field. Moreover, the samples sintered in the temperature gradient and in a 10 T magnetic field have a stronger c-axis alignment ofbi-2223 phase.     

在氮—甲醇混合气中渗碳

1.引言近几年来,热处理厂对用可供选择的供气法来代替传统发生器的吸热气体气氛越来越感兴趣,其原因主要是天然气和丙烷的成本飞速增长。如图1所示,例如从1976年到1982年的天然气价格约上涨了120％。由于80～100％的发生器气体成本(视水费、电费和维护费而定)是由天然气或丙烷的成本所决定的,所以发生器气体的成本也就同样上升了。采用氮-甲醇气氛可以降低保护气体的成本。另外,还有下列各种原因对改用合成供气很为重要: ——能够提高生产;保护气体的成份可灵活多变;载气需要量最佳地适应工况和炉况;可靠性(没有发生器的故障);维修简便;操作     

Computer-aided methods in bespoke breast prosthesis design and fabrication

This case study presents a method of utilizing computer-aided design technologies to provide bespoke, external breast prostheses. The technique is illustrated through a case study of a mastectomy patient. Photogrammetry methods were used to capture the breast form when supported by a brassiere and the unsupported breast and defect side. Computer-aided design techniques were used to generate a digital prosthesis based upon the supported breast shape and with a fitting surface that matched the defect side. Furthermore, a two-part mould was designed and fabricated using rapid prototyping methods. A colour-matched prosthesis was then fabricated in a gel-based, platinum-cured silicone.     

Energy savings by reduced mixing in aeration tanks: results from a full scale investigation and long term implementation at Avedoere wastewater treatment plant

The aim of this project was to investigate the potential of reducing number of mixers in the biological treatment process and thereby achieve energy and economical savings and contribute to cleaner environment. The project was carried out at Avedoere wastewater treatment plant and a full scale investigation was conducted to study the effect of reduced mixing on flow velocity, suspended solid sedimentation, concentration gradients of oxygen and SS with depth and treatment efficiency. The only negative effect observed was on flow velocity; however the velocity was above the critical velocity. The plant has been operating with 50% of its designed number of mixers since September 2007 and long term results also confirm that reduced mixing did not have any negative effect on treatment efficiency. The estimated yearly electricity saving is 0.75 GWh/year.     

The fate of 14C-radiolabelled diclofenac and 4'-hydroxydiclofenac in membrane bioreactor treatment of wastewater

This study aimed at enhancing knowledge on the fate of diclofenac (DF), together with its main human metabolite 4'-hydroxydiclofenac (4'OHDF), during wastewater treatment by using a laboratory-scale membrane bioreactor (MBR). The reactor was fed continuously with non-radiolabelled diclofenac for a one month period prior to a single pulse of a 14C-radiolabelled solution of DF and 4'OHDF. The solution spike contained approximately 25% 4'OHDF and 65% DF, which corresponds to the ratio observed in municipal sewage, as well as traces of two other metabolites. The radioactivity was monitored for a total of twelve days in the various output streams. The calculation of the complete mass balance in the system demonstrated that the major part of the radioactivity left the reactor with the permeate (88.7%), while 2.1% was recovered in the excess sludge. Negligible amounts were recovered in the off-gas traps and on the membranes. Chromatographic analyses of effluent samples, by means of HPLC-MS coupled in parallel to a radiodetector, displayed a different pattern than the one of the spiked solution. It showed the occurrence of three additional metabolites.