瑞雷面波在多尺度勘探上的研究现状与展望

近年来,瑞雷面波勘探的理论研究与实际应用技术发展迅速。根据瑞雷面波的传播特性,瑞雷面波勘探研究及应用范围广泛,从地球内部地壳和上地幔的构造研究(大尺度勘探)到石油地震勘探(中尺度勘探)再到工程勘探(小尺度勘探)以及物体内部特性变化的检查(甚小尺度调查)均有涉及且应用效果良好。因此可以说瑞雷面波法既是研究地球宏观构造的“望远镜”,又是调查物体局部特性变化的“显微镜”。对瑞雷面波勘探的理论研究以及在各尺度勘探的应用情况进行了综述,并对瑞雷面波勘探的理论研究和应用前景进行了展望。     

Replacing incandescent lamps with an LED panel for hydrogen production by photofermentation: Visible and NIR wavelength requirements

Hydrogen production by Rhodobacter capsulatus is a photobiological anaerobic process requiring light as energy source. In this study, the influence of visible and near-infrared (NIR) parts of light spectra from incandescent lamp and LED panels on hydrogen production was investigated. The results showed that the lack of the visible part of the incandescent lamp light spectrum (17% of the lamp light intensity) reduced hydrogen production by 50%. NIR wavelength only partially sustained photofermentation due to light limitation reached at low bacterial concentration. Hydrogen production with NIR light source was only 58% of hydrogen obtained with an incandescent lamp used at the same irradiance. To maximize hydrogen production and flow rate, visible and NIR wavelength should be used concomitantly as light source. Using an energy-efficient LED panel with light spectrum designed to promote photofermentation, hydrogen production and flow rate were equivalent to the ones reached with incandescent lamp as light source.     

LNG发动机缸内气体流动及其对燃烧过程影响的数值分析

应用STAR-CD软件对缸内直喷LNG发动机建立工作过程的计算模型,分析了缸内流场的运动及对发动机燃烧过程的影响.模拟结果表明:进气过程所产生的涡流运动能够维持到压缩上止点附近,压缩行程后期缸内的滚流破裂成众多小尺度的涡,湍流强度增大,可以提高火焰传播速率;压缩冲程接近终了时,缸内混合气呈明显分层现象,在火花塞及LNG喷嘴附近聚集较浓的可燃混合气,利于实现天然气发动机的稀薄燃烧.     

Wireless power charger for wearable medical devices with in‐band communication

A wireless power charger integrated circuit has been developed for wearable medical devices in a 0.18‐µm Bipolar, Complementary metal‐oxide‐semiconductor, and Lightly‐Doped Metal‐Oxide‐Semiconductor (BCDMOS) process. A passive full‐wave rectifier consisting of Schottky diodes and cross‐coupled n‐type Metal‐Oxide‐Semiconductor (nMOS) transistors performs the alternating current to direct current power conversion without any reverse leakage current. To charge a battery, a linear charger circuit follows the passive rectifier instead of a switching charger circuit for the small form factor of wearable medical devices. An in‐band communication circuit notifies the proper connection of the wireless power receiver and the battery charging status to the charging pad (wireless power transmitter) through the wireless power transmission channel. The wireless power charger integrated circuit occupies 1.44‐mm² silicon area and shows 31.7% power efficiency when the charging current is 26.6 mA. Copyright © 2015 John Wiley & Sons, Ltd.     

Understanding makerspace continuance: A self-determination perspective

Makerspaces are informal physical spaces located in community settings or educational institutions where people immerse themselves in creative making. Makerspaces hold incredible potential for fostering essential skills needed for the future and are increasing in number worldwide. Previous research has identified many diverse makerspace initiatives and has demonstrated their potential, but few research has examined makerspace sustainability. Makerspace sustainability is a significant issue as diminished participation, activity, utilization, and retention limit its success. This study examines makerspace sustainability by understanding which factors influence makerspace continuance intention. This study proposes and empirically tests a conceptual framework based on self-determination theory to identify the motivations of makerspace users. An analysis of data collected from 121 South Korean makerspace users indicates that makerspace environmental support is significantly related to a makerspace user’s basic psychological needs. Those psychological needs positively impact intrinsic motivation, which ultimately influences makerspace continuance intention. This research has several implications for academics while recommendations are proposed that have immediate application for practitioners which are informed by the study results.     

Restoring nutrient circularity in a nutrient-saturated area in Germany requires systemic change

Nutrient Cycling in Agroecosystems - Regions with intensive agriculture often encounter environmental problems caused by nutrient excess of agro-food-waste systems that have become increasingly...     

Critical success factors for e-learning in developing countries: A comparative analysis between ICT experts and faculty

This study identifies the critical success factors that influence the acceptance of e-learning systems in developing countries. E-learning is a popular mode of delivering educational materials in higher education by universities throughout the world. This study identifies multiple factors that influence the success of e-learning systems from the literature and compares the relative importance among two stakeholder groups in developing countries, ICT experts and faculty. This study collected 76 usable responses using the Delphi method and Analytic Hierarchy Process (AHP) approach. The results reveal 6 dimensions and 20 critical success factors for e-learning systems in developing countries. Findings illustrate the importance of curriculum design for learning performance. Technology awareness, motivation, and changing learners’ behavior are prerequisites for successful e-learning implementations. Several recommendations are provided to aid the implementation of e-learning systems for developing countries which have relevance for researchers and practitioners. Limitations as well as possible research directions are also discussed.     

Interpenetrating alginate on gelatin–poly(2-hydroxyethyl methacrylate) as a functional polymeric matrix for cartilage tissue engineering

In this work, we report the fabrication of an interpenetrating alginate network on a gelatin and (2-hydroxyethyl methacrylate) (GAH). The anisotropic architecture of scaffold promotes the proliferation of chondrocytes. The anisotropy provided by the alginate influences the cellular response because high collagen and glycosaminoglycan (GAG) contents were found in the cells cultured on the GAH scaffold compared to the scaffold (GH) without alginate. The in vivo experiments demonstrate that the scaffold and the disposition of matrix components, particularly collagen, could promote neovascularization with the ability to recruit cells from the surrounding tissue.     

Good transboundary water governance in the 2015 Sustainable Development Goals: a legal perspective

The goal of this article is to discuss whether the Sustainable Development Goals address the cooperation necessary to facilitate a system of transboundary water governance. For the purpose of this analysis, a Good Transboundary Water Governance Matrix has been developed. We find that transboundary water governance requires a holistic interpretation and implementation of the Sustainable Development Goals understood as a whole. In particular, good governance and, ultimately, sustainable development require stakeholders to focus not only on water (Goal 6) but also on Goal 16, which focuses on international cooperation.     

Efficient dyeing of silica fiber using metal‐coordinated polymeric dye rotaxane

We prepared an azo dye rotaxane and its polymeric metal complex and successfully demonstrated their useful application for dyeing silica fiber, which exhibited high‐color strength and fairly good color fastness. These benefits were made possible by the hydrogen bonding between SiO₂ and hydroxyl groups (? OHs) on α‐cyclodextrin (α‐CD). Spectroscopic evidence supports the formation of polymeric metal‐complexed rotaxanes within the silica fiber. The current results are meaningful because they indicate that the proper adjustment of the interaction between CD and SiO₂ can produce CD‐encapsulated dyes that provide an effective platform for depositing various metal ions on silica surfaces, which will be useful in numerous promising applications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013