FTIR Spectra, Lattice Shrinkage, and Magnetic Properties of CoTi-Substituted M-Type Barium Hexaferrite Nanoparticles

Single-phase BaCoTiFe₁₀O₁₉ (BaCoTi-M) nanoparticles were prepared by a modified sol–gel process, using metallic chlorides as starting materials. The physical chemistry process of BaCoTi-M formation, the interdependences between composition, technological conditions, microstructure, and magnetic properties were studied by X-ray diffraction (XRD), Fourier transform-infrared (FTIR), scanning electron microscope (SEM), transmission electron microscope (TEM), and vibrating sample magnetometer (VSM). XRD and FTIR results show that BaCoTi-M nanoparticles formed directly from γ-Fe₂O₃, spinel ferrite, and barium salts without the formation of α-Fe₂O₃ and BaFe₂O₄. The lattice shrinkage of BaCoTi-M nanoparticles that occurred on increasing the calcining temperature from 973 to 1173 K under holding for 2 h or on increasing the holding time in the range 0–2 h at 1173 K was discovered by analyzing the dependences of lattice parameters on the heat-treatment conditions. The shrinkage led to a relatively higher concentration of magnetic Fe³⁺ cations in the unit cell, and resulted in an increase of specific saturation magnetization under the corresponding conditions. Microstructural characterization shows that the evolutions of coercivity, remnant magnetization, and squareness ratio depended on the crystal growth and the reduction of structural defect as well as a decrease of grain boundary.     

Seismic design requirements for reinforced concrete piers considering aftershock-induced seismic hazard

The main purpose of this study is to develop an estimation procedure of seismic design level setting for reinforced concrete (RC) piers considering aftershock-induced seismic hazards. This work develops an assessment method of the seismic hazards induced by aftershocks and takes an example of the Chi–Chi Earthquake in Taiwan. The number of aftershocks is assumed to follow the modified Gutenberg–Richter law with lower and upper bounds when analysing the cumulative density function of the magnitude of the aftershock within a specified post-mainshock period for the earthquake. Additionally, this work considers the spatial uncertainty in the hypocentres of aftershocks to assess the aftershock-induced seismic hazards. Fragility curves and residual factors of damaged RC piers are used in the transition probability matrix of Markov Chain model for considering the cumulative damage induced by aftershocks by incorporating uncertainty into aftershock events, as well as into structural capacity and residual factors corresponding to a specified damage state, the exceedance probabilities for various damage states can be estimated using Markov Chain model and Monte Carlo Simulation. Finally, in the case study, the proposed procedure is used to determine the important factor in the preliminary seismic design of typical RC piers for the Chi–Chi Earthquake in Taiwan.     

一种变权灰色组合预测模型在中长期电力负荷预测中的应用

提出了一种基于灰色理论的中长期负荷变权组合预测模型,通过分析负荷曲线走向,对不同变化趋势的阶段组合后建立不同的灰色模型分别进行预测,通过基于累加残差的变权组合预测得到最终结果,简单有效地将变权组合预测应用到电力负荷预测中.实例计算证明了该模型在中长期电力负荷预测中的有效性,该模型兼具了灰色模型的简单性和变权组合预测的精确性.     

To mine association rules of customer values via a data mining procedure with improved model: An empirical case study

This paper proposes a new procedure and an improved model to mine association rules of customer values. The market of online shopping industry in Taiwan is the research area. Research method adopts Ward’s method to partition online shopping market into three markets. Customer values are refined from an improved RFMDR model (based on RFM/RFMD model). Supervised Apriori algorithm is employed with customer values to create association rules. These effective rules are suggested to apply on a customized marketing function of a CRM system for enhancing their customer values to be higher grades.     

An expert system approach to assess service performance of travel intermediary

Asian travel industry, in terms of outbound travel markets, has been confronting the global accelerating competition in 21st century. Regarding to the outbound travels, the incumbent travel intermediaries (destination tour operators), the ultimate front-liners of tourism packages provisions is accordingly essential. Technically, estimation on the incumbent travel intermediaries is a series of multiple-criteria decision making (MCDM). Subsequently, this paper executes the implementation of focus group which interviewed 35 travel experts and further integrates the analytic network process approach (ANP) via the insights of host travel agency. Research results objectively enable the Asian travel agencies to evaluate the sustained travel intermediary as well as elaborating the service performance and quality.     

多媒体教学与传统教学在高职教学中的利弊分析

随着计算机技术的迅速发展,高职教育的发展也受到影响．多媒体教学手段的广泛应用,使传统教学方法受到很大冲击,本文阐述了多媒体教学的特点和传统教学的特点及缺陷,寻找一种结合两种教学方法的新型的合适高职的教学方法。     

聚合物共混物对水泥石-石英界面结构影响的机理

就聚合物共混物对水泥石－石英界面结构的影响机理进行了研究,结果表明：在聚合物共混物改性水泥砂浆中,石英表面的水化离解反应因聚合物分子链活性基因的电性作用而失去平衡,导致其表面出现大量带负电荷的「ＨＳｉＯ３」＾－和「ＳｉＯ３」＾２－离子;「ＨＳｉＯ３」＾－和「ＳｉＯ３」＾２－离子与水泥水化阳离子相互作用,在石英表面产生如水化硅酸钙等凝胶状粘结物,从而形成水泥石－石英粘附性界面。     

Photocatalytic decomposition of 2-chlorophenol in aqueous solution by UV/TiO2 process with applied external bias voltage

The decomposition of 2-chlorophenol by UV/TiO2 process with the application of external bias voltage was examined in this study. Experiments were conducted in a batch reactor using TiO2-coated titanium sheet as anode and platinum sheet as cathode. The anode photocatalysis of 2-chlorophenol was totally inhibited for experiments conducted with the application of external anodic bias voltage lower than the flat band potential of TiO2. The decomposition rate of 2-chlorophenol was then increased with increasing external anodic bias voltage applied up to 0.0 V (versus SCE). The application of external bias voltage higher than 1.0 V did not markedly promote the photocatalysis of 2-chlorophenol possibly because the photocurrent induced was constant. Experimental results indicated that the decomposition of 2-chlorophenol was more effective for experiments conducted in acidic solutions due to the lower flat band potential of TiO2 and the higher photocurrent induced. The presence of electron scavengers in aqueous solution, such as oxygen molecules, may increase the decomposition rate of 2-chlorophenol. However, the effect of dissolved oxygen was diminished for experiments conducted with applied external bias voltage. The photocatalytic decomposition rate of 2-chlorophenol was enhanced linearly with the increasing UV light intensity when the external bias voltage was applied.     

分布函数选择方法对质量评价的影响

本文阐述了最小统计量法选择分布函数的基本原理和具体算法,并在此基础上以工程中常用的三种典型分布为例,通过统计模拟,分析了该方法用于质量评价所产生的影响。     

Bi0.5Sb1.5Te3/环氧树脂柔性复合热电厚膜的制备及其面内制冷性能

利用丝网印刷法在聚酰亚胺基板上制备了Bi_0.5Sb_1.5Te₃/环氧树脂柔性复合热电厚膜, 通过优化Bi_0.5Sb_1.5Te₃粉末含量提高了其电输运性能。复合厚膜在300 K时的最优功率因子达到1.12 mW·m ^-1·K ^-2, 较前期报道的数值提高了33%。抗弯测试表明复合厚膜的电阻在弯曲半径大于20 mm时基本不变, 在弯曲半径为20 mm, 弯曲次数小于3000次时, 仅有轻微增大, 说明其在柔性热电器件领域具有应用潜力。红外热成像技术显示, 在工作电流为0.01 A到0.05 A时, 复合厚膜热电臂两端可以形成4.2 ℃到7.8 ℃的温差, 表明了其在面内制冷领域应用的可能性。