Growth and morphology of nanometer LiMn2O4 powder

The growth of Li_1+xMn₂O₄ via detonation reaction was investigated with respect to the presence of an energetic precursor, such as the metallic nitrate and the degree of confinement of the explosive charge. The detonation products were characterized by scanning electron microscopy. Powder X-ray diffraction and transmission electron microscopy were used to characterize the products. Li_1+xMn₂O₄ with 1-2 μm spherical morphology and more uniform secondary particles, but with smaller primary particles of diameters from 20 to 60 nm and a variety of morphologies were found. The oxides produced by this cheap method affirmed the validity of detonation synthesis of nano-size powders.     

Study of miscibility enhancement in poly(styrene‐co‐4‐vinylphenol)/poly(ethylene oxide) blends by the spin labelling method

The electron spin resonance (ESR) spectra of end‐group spin labelled poly(ethylene oxide) (SLPEO) using 2,2,6,6‐tetramethyl‐piperdine‐1‐oxyl nitroxide and its blends with poly(styrene‐co‐4‐vinylphenol) (STVPhs) of different hydroxyl contents were recorded over a wide temperature range. For a blend of SLPEO and pure polystyrene (PS), the ESR spectrum was composed of a single motion component, indicating that PS was immiscible with PEO. For blends composed of SLPEO and different‐hydroxyl‐content STVPhs, two spectral components with different motion rates were observed over a certain temperature range. The difference between the motion rates should be attributed to micro‐heterogeneity in the blends, with the faster rate corresponding to a nitroxide radical motion trapped in the PEO‐rich domain and the slower rate corresponding to a nitroxide radical motion trapped in the STVPh‐rich domain. Variations in the values of a number of the ESR parameters (T_a, T_d and T_50G) and the apparent activation energy (E_a) with hydroxyl content in the blends indicated that the miscibility of the blends increased with increasing hydrogen‐bonding density due to specific interactions between the hydroxyl groups in STVPh and the ether oxygens in PEO. Copyright © 2004 Society of Chemical Industry     

首钢2号高炉的技术进步

介绍首钢2号高炉大修采用的新技术、开炉操作和投产以来的生产情况。     

New bottle but old wine: A research of cyberbullying in schools

This study investigates the nature and the extent of adolescences’ experience of cyberbullying. A survey study of 177 grade seven students in an urban city is conducted. In this paper, “cyberbullying” refers to bullying via electronic communication tools. The results show that almost 54% of the students were victims of traditional bullying and over a quarter of them had been cyber-bullied. Almost one in three students had bullied others in the traditional form, and almost 15% had bullied others using electronic communication tools. Almost 60% of the cyber victims are females, while over 52% of cyber-bullies are males. Majority of the cyber-bully victims and bystanders did not report the incidents to adults.     

Apatite as an interesting seed to remove phosphorus from wastewater in constructed wetlands.

Intensive use of phosphates has resulted in high P levels in surface waters and therefore eutrophication problems. Over the last decade many studies have revealed the advantage of using specific materials with efficient phosphorus retention capacities. Recent studies state that Ca materials are of particular interest for long-term retention of P, but can induce negative effects. To improve P retention and avoid negative counter-effects we tested the potential of natural apatites. Apatite sorption was evaluated using batch and open reactor experiments. Batch experiments identify sorption mechanisms and the influence of the ionic characteristics of the solution; open reactor experiments evaluate sorption capacities in relation to the ionic composition of the solution and biomass development. In parallel, observation of the material by electron microscopy was used to give more precision information about the mechanisms involved. This work reveals the strong chemical affinity between apatites and phosphorus. Compared to other calcareous materials apatite is better able to maintain low outlet P levels. After more than 550 days feeding, sorption was still present and low P outlet levels were still being obtained when sufficient contact time and calcium content in the solution were ensured. This work demonstrates the advantages of using apatites for phosphorus removal in constructed wetlands. The behaviour of apatite in phosphorus retention is explained and its suitability for use in such extensive systems defined.     

GSM技术在配电网故障自动隔离及恢复系统的应用

为了使配电网故障的隔离和恢复的通讯更加可靠、迅速、经济，设计了一种基于GSM通讯技术，借助移动通讯系统短信业务和数据业务，实现配电网故障的自动隔离与恢复的系统。该系统通过MCU采集数据，判断故障位置与故障类型，经GSM通讯模块上传主站，主站统筹全局，实现故障段的切除，非故障区的供电。阐述了系统的工作原理、硬件结构、通讯协议和软件流程。现场的实际运行情况证明数据上报通讯准确率为100％，多次模拟线路故障，根据故障点的不同，一般在2～3min内系统都能可靠的隔离故障，恢复系统。     

Hydrothermal Synthesis of Magnesium Aluminate Platelets

Magnesium aluminate (MgAl₂O₄) platelets were first synthesized by hydrothermal treatment of γ-AlO(OH) in a magnesium nitrate aqueous solution at 400°C. The platelets are 100–200 nm in width and 25 nm in thickness. The influence of temperature, the anions of the magnesium salt, the amount of magnesium salt, and precursor pH on the formation of such structure was investigated. The experimental results indicated that the anions of the magnesium salt and precursor pH could have a significant influence on the growth of MgAl₂O₄. MgAl₂O₄ formation followed the in situ transformation mechanism, which was the reason why the MgAl₂O₄ crystallites had a platelet morphology.     

地方热电联产企业发展对策的探讨

介绍了泰州热电企业的运行情况，分析了各热电厂在技术改造、扩大热用户和强化内部考核管理方面的措施，探讨了地方热电企业应采取的对策和发展思路。