TUBE OCL耳放的制作及调试

“胆机的设计不仅是传统电路与现代元器件之间的一种结合，也是电路与声音的和谐演绎，这当中，虽然有成熟的电路可以借鉴，但也需要通过设计师来凭借其个人智慧和经验将他们予以结合……”——陈德海斯巴克工程师。     

Influence of die geometry on undershooting phenomenon and bending phenomenon in cold extrusion of steel tube

Abstract

Numerical and experimental investigations were carried out on the excessive decrease in outside diameter occurring on a tube cold extruded through two conventional types of die, a taper die and an R die. Wide ranges of the parameters of die profile were adopted in order to precisely examine the influence of die geometry on the undershooting phenomenon, and appropriate die geometries for the suppression of the undershooting phenomenon were shown. The R die is more practical in the manufacturing operation compared with the taper die. Bending was also investigated, and it was shown that the bending intensity becomes lower as the undershooting intensity decreases. However, it is not necessary to suppress bending sufficiently, even if the undershooting is suppressed to zero in the case of adopting the ordinary types of die – there seemed to be another governing factor for the occurrence of bending and this is a remaining problem.     

A Clamp for the Tensile Testing of Fibre Bundles

A theoretical analysis has been developed in which it has been assumed that the two-stage process that occurs during the relaxation of wool yarns leads to the same change in structure as a single dry-relaxation process. In the present paper, a detailed experimental evaluation of the theory is reported whereby its predictions are compared with results obtained for wool semi-worsted carpet yarns spun at various twist levels.     

Wear mechanism in contact tube

Abstract

Stable sliding contact is the most important factor in the stable arc discharge of solid wire. If the contact tube wears seriously, arc discharge will become unstable and the wire position will be shifted. Ordinary non-Cu-coated solid wire causes much wear of the contact tube, about 10 times that caused by Cu-coated solid wire. The mechanism of contact tube wear is not only friction at high temperature, but also a molten bridge formed between the contact tube and wire surface. A complex of superfine particles decreases the amount of contact tube wear. For example, the mixture of graphite and magnetite reduces the amount of contact tube wear by 80%. These particles form an interface layer on the inner surface of the contact tube, and the layer prevents the transfer of molten Cu to the wire surface. The interface layer mainly consists of FeO and complex oxides.     

Preparation of nanoporous silica–zirconia layers by in situ sol–gel method

Abstract

Silica–zirconia membranes were prepared using a sol–gel process, never before used on this system. Thin layers of gel were grown on the outside of porous alumina support tubes using the permeation of water through pores of the tube to control the rate of hydrolysis with a reactive silica–zirconia alkoxide solution. A recipe was developed and optimum coating conditions were found to be the ratios of tetraethylorthosilicate (TEOS) to Zr propoxide to 1-propanol molar ratios (1:0·5:17), with a coating time of 300 s. The method allowed the formation of a membrane in a single step compared with repeated coating and firing. The coatings could be prepared adherent and without cracks when properly prepared.     

Design and error analysis of a high accurate star simulator based on optical splicing technology

Dynamic tar simulator has been widely used in calibration and validation for star trackers.To achieve both high accuracy and large view field,a dynamic star sim...     

基于“TUBE”理论的交叉航路设计研究

针对当前航路网络日趋复杂,航路交叉点越来越多,出现飞行冲突的几率大大增加的问题,提出基于“TUBE”理论的交叉航路设计方法,该设计方法将航路中的航空器抽象为一种流体,当航空器进入航路时采用汇流的方法,离开航路时采用分流的方法,使航空器在飞越航路交叉点时不存在互相穿越的飞行情况,并基于该理论进行了建模计算,计算结果表明该...     

Transformation characteristics of medium carbon V – Ti – N microalloyed steel for non-quenched/tempered oil well tubes

Abstract

The phase transformation points of a medium carbon V - Ti - N microalloyed steel were determined, as were the continuous cooling transformation curves of austenite heated at 1100 ° C without deformation and heated at 1200 ° C with two pass deformation. The data have been further used to analyse the real production scheme of N80 grade hot rolled non-quenched/tempered seamless tubes. The results have showed clearly that the commonly used 'in line normalisation' is not always necessary in the non-quenched/tempered production process of N80 grade hot rolled seamless oil well tubes. The above viewpoint has been further demonstrated by the microstructural examination of specimens sampled from industrial production.     

Hot dip galvanising and galvannealing of P and Mn strengthened TiNb IF steels

Abstract

Phosphorus, Mn, or Si solid solution strengthened sheet steels stabilised with Ti and Nb are known to have poor galvanising and galvannealing properties. When these steels are continuously annealed in higher dewpoint atmospheres, selective oxidation processes can occur in the subsurface region of the sheet. A laboratory simulated continuous galvannealing process was therefore used to study this effect in P and P+Mn solid solution strengthened sheet steels stabilised with Ti and Nb, by making a detailed analysis of the fundamental surface and interface processes that control the wetting of the surface by the liquid Zn, the inhibition layer formation, and the Fe-Zn reaction.     

Submerged laser-induced plasma amplification of shockwaves using shock tubes for nanoparticle removal

Amplifying the dynamic pressure of submerged laser-induced plasma (LIP) shockwaves using shock tubes is introduced and demonstrated. The higher the amplitude of the pressure generated, the smaller the particles that can be removed, thus proving more useful for a variety of nanoparticle removal applications. Limiting the expansion of the submerged LIP core with a shock tube is a non-contact approach to increase pressure amplitude by nearly an order of magnitude for removal of particles, thus minimizing both shockwave and LIP radiation heating damage on the substrate. Radiation heating is identified as one of the major causes of damage in LIP nanoparticle removal and increases as the distance from the LIP core to the substrate decreases. However, submerged LIP shockwaves away from the core demonstrate a pressure decrease in the order of 70% every 5 mm and afterwards remaining comparatively steady. This demonstrates that the shock-tube technique results in higher pressures at distances significantly farther from the core of submerged LIP. In the current investigation, the effect of a set of shock tubes to amplify the transient pressure of the LIP-generated shockwave fronts has been studied to evaluate their specific pressure amplification performances. The effectiveness of a shock tube is quantified in terms of its pressure amplification factor. Through experimental data from several shock tube geometries examined, pressure amplification factors of 8.95 have been experimentally verified which is a ratio of shock tube generated submerged LIP transient pressure of 6.48 MPa to a transient pressure of 724 kPa without a shock tube at the same gap distance d = 2.5 mm. The potential advantages of shock tubes as an underwater amplification approach for predicted 10 nm particle removal are discussed.