模糊讯息分析法评估砂性土液化潜能

本文以Ｓｅｅｄ和Ｉｄｒｉｓｓ简化法为机率分析法的基础，利用模糊讯息分析的基本理论并考虑砂性土基本动态特性所建立的模糊关系，进行砂性土液化潜能评估。计算结果与机率分析及蒙地卡罗模拟法结果互相对比、验证，表明模糊讯息分析对砂性土液化潜能可提供明确评估。     

台灣高鐵隧道工程施工現況

概述了台灣高鐵隧道的設計要求、沿線地質概況及岩體分類、典型地質之隧道施工方式、軟弱地質之輔助工法以及至2003年3月31日止的施工進度。     

A performance-based approach to project assignment and performance evaluation

Project assignment and performance evaluation have been addressed as two important and separate research issues in project management. This paper develops a new performance-based approach for integrating the project assignment and the performance evaluation processes in a project-based organization. An objective-oriented preference-based assignment process is developed to assign a project to a project manager. An optimal project assignment model is developed to maximize the total weighted contribution value of all new projects to the organizational objectives. An efficiency-based evaluation process is developed using data envelopment analysis to measure the relative performance efficiency of the completed projects and of the project managers. The approach provides a proactive mechanism for facilitating objective-focused management of projects. The outcomes of an empirical study conducted provide managerial insights in assigning projects to project managers and in evaluating the performance efficiency of both projects and project managers.     

Adjustment behaviour of capital structure over the business cycles: evidence from the construction industry of Taiwan

Prior studies have found that firms may deviate from the target capital structure in the short run and adjust towards the target in the long run. However, little attention has been given to the adjustment behaviour of capital structure in the construction industry over the business cycles, in particular within the context of emerging markets. The partial adjustment model with the GMM (i.e. generalized method of moments) estimation is used to examine the adjustment behaviour of capital structure in the construction industry within the context of Taiwan during the period 1982 to 2007. The results suggest that, first, the average rate of adjustment is 26.3% of the adjustment gap between the target debt ratios and the previous debt ratios for firms in the construction industry of Taiwan. However, the average rate of adjustment towards the target debt ratios has slowed down after the Asian financial crisis of 1997. Secondly, firms with the financial constraint of over‐leverage relative to the target debt ratios have lower debt ratios than those firms with the financial constraint of under‐leverage. In addition, the difference in debt ratios between firms with the financial constraint of over‐leverage and under‐leverage has become narrower after the Asian financial crisis. Lastly, the findings suggest that macroeconomic conditions do not have a significant, negative effect on debt ratios.     

Enhanced PCE dechlorination by biobarrier systems under different redox conditions

The industrial solvent tetrachloroethylene (PCE) is among the most ubiquitous chlorinated compounds found in groundwater contamination. The objective of this study was to evaluate the (1) feasibility of enhancing PCE biodegradation using cane molasses and sludge cakes as the primary substrates under methanogenic and iron reducing conditions, and (2) potential of installation a sludge cake/cane molasses biobarrier to clean up PCE-contaminated aquifers. The biodegradability of sludge cake (from secondary wastewater treatment system) and cane molasses was tested using bioavailability experiments. Results show that biodegradable materials were released from sludge cake/cane molasses and utilized by microbial consortia. Based on the chemical oxygen demand (COD) tests, approximately 28 and 248 mg of biodegradable COD can be released from 1 g of sludge cake and 1 g of cane molasses under anaerobic conditions, which have the potential to convert 70 and 620 mg of PCE to ethylene (ETH), respectively. Reductive dechlorination was evaluated using microcosms containing primary substrates (sludge cake/cane molasses) and inocula (aquifer sediments). Results indicate that sludge cake and cane molasses can serve as the diffusion sources of primary substrates, and enhance the reductive dechlorination of PCE under methanogenic processes. However, results from this study were not sufficient enough to show that reductive dechlorination of PCE would occur under iron-reducing conditions. This indicates that more studies need to be performed to further evaluate the role of iron reduction on the PCE dechlorination. Results reveal that it is feasible and applicable to install a sludge cake or cane molasses biobarrier to clean up PCE contaminated aquifers. From an engineering point of view, the sludge cake/cane molasses biobarrier has the potential to become an environmentally and economically acceptable technology for PCE bioremediation.     

Physical study of room‐temperature‐cured epoxy/thermally reduced graphene oxides with various contents of oxygen‐containing groups

In this study, the effects of different oxygen‐containing group contents in thermally reduced graphene oxides (TRGs) for enhancing the physical properties of epoxy nancomposites was examined. The epoxy/TRG nanocomposites (ETNs) were prepared by a room temperature curing method in the presence of TRGs containing different oxygen‐containing groups and were then characterized by Fourier transform infrared spectroscopy. TRG contents with higher oxygen‐containing group contents (ca 33%) were found to show better dispersion capability in the epoxy matrix than TRGs with lower oxygen‐containing group contents (ca 11%) based on morphological observations by transmission electron microscopy. The better dispersion capability of TRGs with higher oxygen‐containing group contents in ETN membranes was found to lead to significantly enhanced mechanical strength, thermal stability and thermal conductivity based on measurements of dynamic mechanical analysis, tensile tests, thermogravimetric analysis and by the transient plane source technique. © 2014 The Authors. Polymer International published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry     

Effects of excess boron on combustion synthesis of alumina–tantalum boride composites

TaB- and TaB₂–Al₂O₃ in situ composites were fabricated by thermite-incorporated combustion synthesis from the powder mixtures of different combinations, including Ta₂O₅–Al–B, Ta₂O₅–Al–B₂O₃–B, and Ta₂O₅–B₂O₃–Al. Effects of excess boron were studied on the combustion dynamics and phase constituents of final products. For the B₂O₃-containing samples, the reaction was less exothermic and aluminothermic reduction of Ta₂O₅ and B₂O₃ was less complete, resulting in the deficiency of boron and the presence of TaO₂ and Ta. For the samples containing elemental boron, the occurrence of borothermic reduction of Ta₂O₅ also caused the loss of boron. Experimental evidence showed that boron in excess of the stoichiometric amount substantially enhanced the formation of tantalum borides, which in turn facilitated the reduction of Ta₂O₅ by Al. Consequently, the samples rich with boron in the molar proportions of Ta₂O₅:Al:B=3:10:9 and 3:10:16 (i.e., B/Ta=1.5 and 2.67) were found to be the optimum stoichiometries of producing TaB- and TaB₂–Al₂O₃ composites through a self-sustaining combustion process.     

Circulating YKL-40 Level,but not CHI3L1 Gene Variants,Is Associated with Atherosclerosis-Related Quantitative Traits and the Risk of Peripheral Artery Disease

YKL-40, a pleotropic cytokine, is emerging as a risk factor and a prognostic predictor of atherosclerotic cardiovascular disease. We attempted to elucidate the genetic, clinical and biochemical correlates of circulating YKL-40 level and, by combining it with CHI3L1 gene variants, with the risk and long-term mortality of peripheral artery disease (PAD). Plasma YKL-40 concentrations were measured in 612 Taiwanese individuals who had no clinically overt systemic disease. Clinical parameters, CHI3L1 gene promoter variants and 18 biomarker levels were analyzed. Eighty-six PAD patients were further enrolled for analysis. Significant associations were found between CHI3L1 genotypes/haplotypes and YKL-40 levels for the health examination subjects (smallest p = 8.36 × 10⁻⁷ for rs4950928 and smallest p = 1.72 × 10⁻¹⁰ for haplotype TGG) and also for PAD patients. For the health examination subjects, circulating YKL-40 level, but not CHI3L1 gene variants, were positively associated with age, smoking, and circulating levels of triglyceride, lipocalin 2 and multiple inflammatory biomarkers and negatively associated with low-density-lipoprotein cholesterol levels. Circulating YKL-40 level is also significantly associated with the risk of PAD (p = 3.3 × 10⁻²³). Circulating YKL40 level, but not CHI3L1 gene promoter variants, is associated with the risk of PAD in Taiwanese. The association of YKL-40 levels with multiple quantitative traits relating to the risk of PAD may provide a molecular basis linking YKL-40 to atherosclerotic cardiovascular disease.     

Fundamentals and Modeling of Electrokinetic Transport in Nanochannels

When the channel size approaches the thickness of the charged layer (typically, ∼10–100 nm), the resulting molecular and non-equilibrium effects are markedly different from those observed in larger channels and have a significant effect on the transport behavior of solutes and solvents. As a result, the problem of modeling fluidic behavior at the nanoscale has attracted increasing interest in recent years. This review introduces the fundamental theories and principles associated with electrokinetic transport and molecular dynamics modeling, and discusses various applications of nanofluidic devices in the physics, mechanics, and chemistry fields.     

Polarity Effect in a Sn3Ag0.5Cu/Bismuth Telluride Thermoelectric System

This study investigates electromigration in Bi₂Te₃ thermoelectric (TE) material systems and the effectiveness of the diffusion barrier under current. The Peltier effect on the interfacial reaction was decoupled from the effect of electromigration. After connecting p- and n-type Bi₂Te₃ to Sn3Ag0.5Cu (SAC305) solders, different current densities were applied at varying temperatures. The Bi₂Te₃ samples were fabricated by the spark plasma sintering technique, and an electroless nickel-phosphorous (Ni-P) layer was deposited at the solder/TE interfaces. The experimental results confirm the importance of the Ni diffusion barrier in joint reliability. Intermetallic compound layers (Cu,Ni)₆Sn₅ and NiTe formed at the solder/Ni-P and Ni-P/substrate interfaces, respectively. The experimental results indicate that the mechanism of NiTe and (Cu,Ni)₆Sn₅ compound growth was dominated by the Peltier effect at high current density. When the current density was low, the growth of NiTe was affected by electromigration but the changes of thickness for (Cu,Ni)₆Sn₅ were not obvious.