Development of High Deformability Pipeline Steel

Based on strain-based design, high deformability X70 high strength pipeline steel with dual-phase microstructure has been developed, which can be laid in the seismic, the cold or the deepwater region. The results illustrated that the developed X70 steel has the stress-strain curve like round house and it shows good anti-transformation characteristic, high uniform deformation(≥10%), enhanced n-value(≥0.10), and the low yield-tensile ratio Y/T(≤0.85). The dual-phase microstructure of ferrite and bainite conta...     

Cobalt-iron cyanide hollow cubes: Three-dimensional self-assembly and magnetic properties

Cobalt-iron cyanide hollow cubes have been synthesized via a poly(vinylpyrrolidone) assisted solvothermal route. A unique formation process: self-assembly followed by Ostwald ripening process, has been put forward to take account for the construction of hollow cubes. The rod-like nanocrystals first assemble as porous cubes via an oriented attachment process. Then, the porous cubes undergo an Ostwald-ripening process, which create interior spaces and result in the formation of hollow cubes. The magnetic property investigation reveals that K_0.22Co_0.58Fe_2.2(CN)₆ hollow cubes exhibit a ferromagnetic behavior.     

Effects of phospholipid hydroperoxide glutathione peroxidase mRNA expression on meat quality of <Emphasis Type=Italic>M. longissimus dorsi</Emphasis> in pigs

Antioxidant enzymes protect muscle tissues against oxidation from reactive oxygen species and increase the stability of the muscle. Phospholipid hydroperoxide glutathione peroxidase (GPx4) is an important antioxidant enzyme in muscle tissue. So the aim of this study was to identify the effects of mRNA expression level of GPx4 gene on meat quality properties in Longissimus dorsi of three pig breeds. Total 36 pigs (12 pigs for each breed) were used to measure the meat quality properties and to analyze the expression levels of GPx4 gene by quantitative real-time PCR. The results showed that meat quality, GPx4 activity, and GPx4 mRNA levels were affected by pig breeds. There were the lowest expressible moisture, drip loss, and cooking loss in Laiwu Pig among the three breeds, and also there were the highest GPx4 activity and the expression levels of GPx4 gene in Laiwu Pig compared with the other two pig breeds. Analysis of meat samples divergent for water-holding capacity identified highly negative associations between expressions levels of GPx4 gene and expressible moisture, drip loss and cooking loss. These results suggest that the higher mRNA expression level of GPx4 gene up-regulate the water-holding capacity and the activity of GPx4, and the expression of GPx4 gene plays an important role in physiological changes related to the meat quality properties and the mechanisms of the antioxidant ion of meat.     

A new sheet metal forming system based on incremental punching, part 2: machine building and experiment results

The paper is the second of the two papers on a new sheet metal forming system of incremental punching. In the first paper, the mechanics model is introduced, and the computer simulations are carried out. This paper consists of two parts: the design and building of an incremental punching machine and experiment results. The machine is a three-axis computer numerical controlled (CNC) machine with a high-speed hydraulic punching head. Given a part, the punch path can be generated using commercial CAM systems with some modifications. Then, the machine takes over forming the part punch by punch. The formability of this system is also investigated giving the maximum forming angle. Following the first paper, two examples are studied in details. The experiment results indicate that the new system is effective for sheet metal rapid prototyping. Finally, some future research topics are discussed.     

CS夹芯板抗弯性能的试验研究

通过CS夹芯板抗弯性能的试验,重点研究织物加强对改善夹芯板抗弯及抗裂性能的作用。试验研究表明,织物加强的CS夹芯板具有很好的抗弯抗裂性能。并根据受弯机理分析,提出相应的开裂弯矩和极限弯矩计算公式,计算结果与试验结果吻合较好。     

"电工电子学"课程教学改革的探索与实践

"电工电子学"是高等工科院校非电专业的一门重要技术基础课.针对学生基础差异大、学时数量有限等课程特点,江苏大学从教学实际出发,整合、优化教学内容,采用多元化的教学模式以及加强实践教学等一系列改革措施,把更多、更新、更广的内容融入课堂和实践教学中,取得了良好的教学效果.     

大入地短路电流造成发电厂局部电势超标的研究

新建大型发电厂单机容量超过GW,投网运行台数超过2台.若厂区内发生不对称接地短路故障,则可能入地电流过大,造成设计人工接地装置接地电阻值大于A类电气装置允许接地电阻值上限;且校核局部接触电势和跨步电势超出设计规范要求.因此,根据实际工程特点,提出局部增设小网孔水平均压带且铺设砾石提到地面电阻率.结果方案满足工程设计标准.     

The application of recurrence plot in DC tracking test of gamma-ray irradiated polycarbonate

Irradiation effects on tracking resistance of polymer insulation materials should be investigated due to the increasing usage in radiation-prone environments. This paper presents a study on dc tracking resistance of gamma-ray irradiated polycarbonate mixed with polyethylene by use of IEC 60112 method. The samples were irradiated in air up to 100 kGy and 1000 kGy with a dosage rate of 10 kGy/h using a /sup 60/Co gamma source. Because the data of tracking resistance obtained from the tracking test has a wide variation, discharge current in the test is considered as a main factor to estimate the tracking resistance. A recurrence plot analysis of discharge current has been made to evaluate the tracking resistance more consistently. Obtained results showed that after gamma-ray irradiation, the tracking resistance was improved compared with that of the unirradiated sample. The tracking resistance showed an increasing tendency from 0 kGy to 100 kGy but a decreasing tendency from 100 kGy to 1000 kGy. There was a threshold value for the tracking resistance around 100 kGy, which was related to the reaction of cross-linking and degradation. The topological structures of the recurrence plots with the irradiated samples were different from that of the unirradiated one. There were bigger white space segments, which indicated that there were high amplitude transients in the discharge currents of unirradiated sample. The recurrence point density increased from 100 kGy to 1000 kGy, which suggested that the discharge process of the total dose at 1000 kGy was more intensive than that at 100 kGy. The irradiation effects on the tracking resistance can be visually identified by the recurrence plot.     

A DC Signal Injection-Based Thermal Protection Scheme for Soft-Starter-Connected Induction Motors

This paper proposes a remote and sensorless thermal protection scheme for soft-starter-connected induction motors. A dc signal injection-based method is used to estimate the stator winding resistance and, thus, the stator winding temperature. Based on continuous monitoring of the stator winding temperature, a thermal condition monitoring and protection scheme is proposed using only the motor's input voltages, currents, motor nameplate information, and the ambient temperature. An adaptive Kalman filter is designed to reduce the stator winding temperature estimation error. In addition, the influence of the cable resistance was investigated, and a compensation method is suggested to improve the accuracy of the estimated temperature. The requirements of the data acquisition system, such as sampling frequency and analog-to-digital conversion resolution, and their affects on the accuracy of the estimated temperature are also discussed in detail. The proposed thermal monitoring scheme has been validated from the experimental results of a 7.5-hp TEFC induction motor under various load conditions. The importance of this new thermal monitoring scheme lies in its remote and sensorless nature.     

实时数据库及在电厂集成自动化系统中的应用

从控制信息系统集成角度出发 ,在简述火力发电厂自动化发展的基本现状和分析比较实时数据库与关系数据库异同的基础上 ,结合萧山电厂集成自动化系统项目 ,总结了实时数据库工程应用的关键技术 ,最后提出了实时数据库的选型原则。