Practical Application of ±250‐kV DC‐XLPE Cable for Hokkaido–Honshu HVDC Link

The long‐term dc properties of DC‐XLPE insulation materials, which have been developed for dc use, were investigated. It was found that the lifetime of DC‐XLPE under dc voltage application is extended by the addition of nano‐sized filler. The time dependence of the space charge distribution at 50 kV/mm was observed for 7 days. Almost no accumulation of space charge in DC‐XLPE was found. The 250‐kV DC‐XLPE cables and accessories were manufactured and subjected to a type test and PQ test for use in the Hokkaido–Honshu dc link facility owned by the Electric Power Development Co., Ltd. These tests were performed under conditions that included a polarity reversal test for line commutated converter (LCC) systems as recommended in CIGRE TB 219. The test temperature was 90 °C. The type test and PQ test were successfully completed. The DC‐XLPE cable and accessories were installed in summer 2012 for the Hokkaido–Honshu dc link. After the installation of the dc extruded cable system, a dc high‐voltage test at 362.5 kV (=1.45 PU) for 15 min was successfully completed in accordance with CIGRE TB 219. This dc extruded cable system was put into operation in December 2012 as the world's highest‐voltage extruded dc cable in service and the world's first dc extruded cable for a LCC system including polarity reversal operation.     

Nanowrinkled and Nanoporous Polyethylene Membranes Via Entanglement Arrangement Control

Crystalline homopolymers, including polyethylene (PE), which has the simplest architecture, form a nanometer‐sized combination of crystalline and amorphous components, but their arrangement control, similar to self‐assembled phase‐separation of block‐copolymers, is usually difficult. However, molecular entanglements trapped between crystalline and amorphous components of homopolymers coincide with the segmental linking points on the interfaces of the microphase separation for block copolymers. Nanowrinkled PE membranes are prepared with a network of 30 nm‐thick homogeneous lamellae using a novel entanglement control technique composed of biaxial melt‐drawing and melt‐shrinking procedures, which are limited for highly entangled ultrahigh molecular weight materials. Such a network arrangement of nanowrinkling lamellae spreading on membrane surface and also across the membrane thickness improves the mechanical properties of both tensile strength and tearing strength. Subsequent cold‐drawing causes delamination of the lamellar interfaces, leading to the resultant nanoporous morphology composed of passing‐through channels that are several tens of nanometers in diameter, without any solvent processing.     

国内外塑料管道原料现状与发展趋势

介绍近年来塑料管道原材料的研发状况,并就开发塑料管材料新产品以及开发压力管道原料定级提出了建议,为管材原料生产厂、管材生产商、施工设计和使用者提供参考。     

高密度聚乙烯装置循环气冷却器腐蚀原因分析及防护

针对高密度聚乙烯装置循环气冷却器在使用中存在的腐蚀问题进行分析。通过采用相应的防护办法,取得良好的效果。     

添加剂对高模量沥青及其混合料性能的影响

为了给沥青路面推荐较优高模量沥青混合料添加材料,采用车辙试验、冻融劈裂试验和小梁弯曲试验,以试件的最大变形、冻融劈裂强度比(TSR)和疲劳寿命为评价指标,对比研究了苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)和聚乙烯(PE)两种添加材料,在不同添加剂量条件下对比沥青混合料的性能作用效果。根据研究结果在夏季高温地区,建议采用添加剂量为4.0%的聚合物SBS;在夏季多雨地区或者交通量繁重路段,建议聚合物SBS和聚乙烯PE混合使用,并且掺量为3%。     

Influence of fabric structure and thickness on the ballistic impact behavior of Ultrahigh molecular weight polyethylene composite laminate

This paper presents the influence of fabric structure and thickness on the ballistic impact behavior of Ultrahigh molecular weight polyethylene (UHMWPE) composite laminate. UHMWPE composite laminates, reinforced by three kinds of fabric structures, unidirectional prepreg, 2D plain-woven and 3D single-ply orthogonal woven fabrics, were fabricated via hot pressing curing process. Through a series of standard ballistic tests, we demonstrated that unidirectional composite laminates exhibit higher ballistic impact velocity and absorbed energy capacity compared to others. A bi-linear relationship was found between the ballistic limit velocity and specimen thickness. Furthermore, the dominant failure mechanisms of unidirectional composite laminates were identified to be plugging and hole friction for thin laminates, whereas delamination, fiber tension and bulging for thick ones.     

透视聚乙烯的注塑产品生产加工技术

注塑成型是受热融化的材料由高压射入模腔,经冷却固化后,得到成形品的方法。该方法适用于形状复杂部件的批量生产,是重要的加工方法之一。从注塑用聚乙烯结构特点及其主要原料,分析了聚乙烯注塑成型生产工艺及方法,综述了聚乙烯注塑产品的加工要点,同时指出了聚乙烯注塑产品加工市场的发展趋势。     

Injectable polyethylene glycol-laponite composite hydrogels as articular cartilage scaffolds with superior mechanical and rheological properties

In this study, injectable PEG-based hydrogels containing Laponite particles with mechanical and structural properties close to the natural articular cartilage are introduced. The nanocomposites are fabricated by imide ring opening reactions utilizing synthesized copolymers containing PEG blocks and nanoclay through a two-step thermal poly-(amic acid) process. Butane diamine is used as nucleophilic reagent and hydrogels with interconnected pores with sizes in the range of 100–250?µm are prepared. Improved viscoelastic properties compared with the conventional PEG hydrogels are shown. Evaluation of cell viability utilizing human mesenchymal stem cells determines cytocompatibility of the nanocomposite hydrogels.