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The aperiodic impulse voltage generator is huge and difficult to move in field, thereby limits its application in field significantly. For this problem, the oscillating impulse voltage (OIV) is recommended in standard IEC60060-3. In order to study the influence factor of oscillating impulse voltage generator, the simulation circuit is set up using ATP software. The influence of parameters such as shaping resistors, load capacitance and shaping inductance are study in this paper.

Once the GIS appears screws loose and other phenomena, it will lead to the generation of floating potential, then trigger the floating potential discharge. In order to study the discharge characteristics of the floating potential, this paper artificially built floating potential defects on the GIS malfunction simulation platform, and detected with ultrasound and UHF methods. The results show that once the floating potential discharged, it would produce a larger amplitude signal. And the discharge most concentrated between the zero crossing and the peak point among the entire phase range. Ultrasound and UHF detection has obvious signal.

In order to accurately analyze the field test results of the partial discharge in GIS and study on the partial discharge characteristics of typical insulation defects in GIS, this paper constructs a set of failure simulation test system which is based on the entity 363kV GIS which contains all the Main equipments. These system has artificial defect setting units and can applied voltage and current at the same time, it also can manually set a variety of GIS typical insulation defects at the defect setting units. The partial discharge detection and analysis in the case of the applied voltage and current can simulate actual field operating conditions of GIS.

Traditional English classroom teaching can't meet the needs of the modern information society, the development of English learning resources website is extension and expansion of traditional English teaching. Database design is the basis and prerequisite for the website construction, this paper studies the Oracle database management system under the support of database design. First of all, based on the need analysis to design concept structure, and through the E-R model to express the design results; Finally, the characters, Numbers, time, large object and other five kinds of data type selection Then, on the basis of the clear logical structure design principles to design logical structure; In this paper, the research content, for the development of English learning resources website provides a feasible solution, has the vital significance to the English teaching reform, improve the quality of English teaching.

Traditional teaching management mode can't meet the needs of the teaching management information age, to develop the management system of college English learning, is the extension and expansion of conventional English teaching in English teaching and the inevitable requirement to improve the quality of English teaching. Aiming at the existing problem of system development, this paper makes research on the frame structure. First of all, the research consists of eight functions to complete the whole learning process management function framework; then, study on the technology framework is composed of model, view and controller, design concept is decoupling performance logic and business logic through controller; Finally, the work principle of the struts2 framework, and the working process is described. In this paper, the research content, improve the labor productivity of software development, changed the traditional mode of software development, plays an important role in improving college students' English level.

Insulated copper busbar is widely used as a new type of electrical equipment in recent years. The joint of the busbar is linked with soft connection copper belt in the field. So, it is very easily lead to the metal protrusion defect at the joint. The metal protrusion detect at joint with entity insulated copper busbar is builded in lab. The partial discharge characteristics of this defect is studied under different applied voltage and the results show that such defect has apparent polarity effect, the discharge always appears in the negative half cycle. The discharge amplitude will not be increased very much with increasing of applied voltage but the discharge frequency will be increased significantly. The results provide the basis of laboratory studies for the field testing of insulated copper busbar.

Slide gates are installed at the bottom of a ladle or tundish to control the flow of molten steel. It plays an important role in ladle refining process and continuous casting. Al2O3-ZrO2-C refractories are widely used as slide gate materials due to its excellent corrosion and thermal shock resistance. At the start of casting, molten steel almost 1600°C passes through the bore of slide gate, the plate is rapidly heated up, the temperature difference between the bore and edge part, the slide gates are subject to large thermal gradients, so there is large thermal stress in the plate. This paper will show the results of our improved slide gates with good thermal shock resistance.

Four common subtropical understory sun plants from South China, i.e., Euodia lepta (Spreng.)Merr. (EL), Ilex asprella Champ. (IA), Mussaenda pubescens Ait.f. (MP), and Rhodomyrtus tomentosa (Ait.) Hassk. (RT), were sampled and determined for leaf Cu, Zn, Cd, and Pb concentrations, with an aim to investigate geographic variations in leaf heavy metal concentrations and phytoaccumulation. Significant differences were found among the 4 sampling sites for soil pH and heavy metal concentrations of Zn, Cd and Pb, with higher acidity in the 3 sampling sites from the Pearl River Delta industrial area. However, leaf pH did not vary significantly among the geographic populations of El and MP. For leaf heavy metal concentrations, significant variations were observed among the geographic populations of El for Cd; IA for Zn, Cd, and Pb; MP for Cu, Zn, Pb, and Cd; RT for Zn and Pb. The mean Biological Accumulation Coefficients (BACs) of IA for Zn, Cd, and Pb were as high as 10.38 for Zn, 18.29 for Cd, and 1.76 for Pb, respectively. Coefficient of Variation (CV) of BACs for heavy metals among different geographic populations of each species ranged from 41.99~221.83%, indicating high geographic variability in phytoaccumulation of heavy metals, and their accumulation capacity declined with the increase of soil heavy metal concentrations. This study revealed that some particular populations of IA can serve as potential hyperaccumulators for Zn and Cd, while those of MP and RT as hyperaccumulators for Pb, and the toxicity and safety of RT and IA should be further studied and assessed.

Nowadays online quality estimation for the resistance spot welding (RSW) has benefited a lot from monitoring the electrode displacement caused by nugget thermal expansion. Based on these emerging monitoring techniques a new approach is proposed to classify the weld quality and assure the quality for mass-produced weld group, which enables the continuous quality improvement concept during the welding process. A causal models are built with the offline trained Bayesian Belief Networks (BBN). It is a weld quality assessment net reveals the dependency of the weld quality on the features displayed by the displacement curve, which can be used for overdesigning the safety welds or as the probabilistic forecasting model for online weld quality assessment. The experimental results show that the proposed approach is valid and feasible to predict the weld quality and assure the overall quality for weld group in real applications.

Different chitosan carboxylic salts were successfully prepared via a simple way using chitosan and oxalic, fumaric, salicylic acid for the first time. The characterizations of the salts were evaluated by FT-IR, 13C NMR, 1H NMR, elemental analysis, XRD. The solution properties and moisture absorption-retention abilities of the salts were compared with chitosan. The result indicated that chitosan and carboxylic acid were combined with salt bond. The properties of the salts were related to the type of carboxylic acid added and the formation of salt bond. The water-solubility, wetting effect and moisture-retention absorption abilities of the salts were better than chitosan. They therefore have the potential to substitute for chitosan for easy use as coating in food preservation.