Development of Bi(Pb)-2223/Ag pancake-shaped and solenoidal coils

High temperature superconducting (HTSC) multifilamentary (MT) Bi(Pb)-2223/Ag tapes with reproducible critical current density of between 15000 and 20000 A/cm² at 77 K in self field have been achieved using the standard flat-rolling method as the intermediate deformation between sintering periods. Long lengths of Bi(Pb)-2223/Ag MT tapes up to 43 m prepared by the conventional method of powder-in-tube (PIT) have been successfully produced on a laboratory scale. Several coils have been fabricated from sections of the long length tape, using the co-wound wind-and-react (W&R) procedure for the pancake-shaped and the singly-wound W&R as well as R&W procedure for the solenoidal coils. A novel W&R solenoidal coil (reaching ~973 ampere-turns) wound on an alumina ceramic tube generates a DC field of ~19 mT at 77 K and has been fabricated together with five pancake-shaped coils, each generating an average of ~5 mT at 77 K. These are destined for magnet construction with a possible combined calculated field of ~0.04 T at 77 K (with liquid nitrogen as a coolant)     

太钢电弧炉上应用四星接法MOA的必要性

分析了太钢电弧炉变压器高压侧相间过电压的产生原因，比较了用于限制过电压的避雷器的两种接法．结论是用四垦接法ＭＯＡ限制过电压的效果较显著．     

A Method of Combined SHPB Technique and BP Neural Network to Study Impact Response of Materials

Abstract:  A new method combining the split Hopkinson pressure bar (SHPB) technique with the back-propagation (BP) neural network program is proposed. By this method, the treated strain wave signals become smooth with less noises induced by the transverse inertia. Moreover, the dynamic rate-dependent constitutive behaviour of materials can be identified, without any pre-assumption of a constitutive model. It is found that by taking the experimentally measured data of strain, strain rate and time as 'input' and the corresponding data of stress as 'output' of the BP neural network, the dynamic constitutive behaviour with internal damage or phase transformation evolution is easy to be identified, where the time could represent either the internal damage evolution or phase transformation process accompanied with the deformation process. It is emphasised that the data learnt by the BP neural network must include both loading and unloading processes, if the whole loading and unloading response is to be correctly predicted. The comparisons between the predictions and experimental results are in good agreement for both polyamide (PA) polymer (as an example of nonlinear viscoelastic materials) and Ti–Ni alloy (as an example of superelastic materials with stress-induced phase transformation).     

高非线性光纤及其应用

介绍了各种高非线性光纤的原理，并对其在超连续（SC）脉冲的产生和波长变换上的应用作了讨论。     

宣汉——达县地区飞仙关组储层预测方法研究

在宣汉-达县地区,以往仅依据地震属性来预测飞仙关组储层分布,钻探结果与实际情况不符,为此本文提出量化分析预测结合主参数分析的新方法和新思路。在量化分析中首先对飞仙关组储层进行高分辨率反演,获得储能系数图;然后结合主振幅剖面和主频率剖面分析,对储层进行预测。在研究区,本方法的预测结果与实钻情况相吻合。     

工艺空气压缩机组开车过程的思考

通过汽轮机组调速系统伺服马达不复位、主汽门不动作，反推出电磁阀控制线路接线错误，用人为短路压力开关等手段判断出组合油脱扣器活塞卡涩是造成现场延误开车的根本原因，提出完善大机组开车工作票制度、提高人员素质等措施。     

High power mid-infrared optically pumped PbSe/PbSrSe multiple-quantum-well vertical-cavity surface-emitting laser operation at 325 K

A high power, mid-infrared (/spl lambda/=3.8 /spl mu/m) lead-salt vertical-cavity surface-emitting laser (VCSEL) operating at 325 K is demonstrated. The laser emission is generated in a half-wavelength microcavity consisting of seven pairs of PbSe/PbSrSe multiple-quantum-wells embedded in two mirrors and optically pumped with 5 ns laser pulses.     

永州市抗御"碧利斯"台风的实践与思考

受2006年第四号台风“碧利斯”的影响,永州市出现了持续的强降雨过程,部分地区出现了大暴雨,引发了严重的洪涝灾害,成为近年来影响较为严重的一次台风暴雨。永州市在抗御这次台风暴雨过程中,高度警惕,充分准备,周密部署,科学调度,全力以赴抗灾救灾,将灾害损失降到了最低程度,全市没有垮一库一坝,没有因山洪灾害发生人员伤亡。文章总结了永州市的防灾抗灾经验,并针对防御台风暴雨存在的问题,探讨了进一步减轻台风暴雨灾害损失的对策。