Effect of atomic ordering on hydrogen dissociation on Ni₃Fe surfaces

2008-2009 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Ocean Solid Monitoring Temporal and Spatial Data Organization, Management and Application

In the ocean dynamical environment real-time solid monitoring system of Taiwan Strait and adjacent maritime region, multiple monitoring data including remote sensing data, structured data is produced by the solid monitoring net from airspace, ocean surface and under ocean surface. The storage, management, online analysis service of the monitoring temporal and spatial data is key part of the whole system. Aiming to resolve the data organization and integrated analysis service of the monitoring data, this paper studies the characteristics, design and application of the temporal and spatial data warehouse of ocean solid monitoring information. Firstly, the characteristics and application model of the data warehouse of ocean solid monitoring information is introduced from the aspects of spatial, temporal, subject-oriented, multiple resource and decision-making oriented. Then the subject classification, design of concept module of the data warehouse of ocean solid monitoring information is introduced. The Star Schema is used to demonstrate the multi-dimension character of the ocean monitoring information. At last, the data warehouse of ocean solid monitoring data based application in shipwreck salvation decision-making support system of Taiwan Strait is realized

Ocean Observing Data Web Service and Application in Shipwreck Salvation of Taiwan Strait

In the ocean dynamical environment real-time observing system of Taiwan Strait and adjacent maritime region, multiple observing data such as remote sensing data, structured data and so on are produced by the observing net from airspace, ocean surface, underwater space and ocean bottom. The data sharing and web service is a key part to influence the application efficiency of the whole system. According to the characteristics of the oceanic dynamical environment of Taiwan Strait, the construction scheme of the observing net is introduced in this paper firstly. Then the architecture of the observing data sharing and web service system is introduced, which includes four parts, i.e. the observing data acquiring module, the data integration module, the data processing and information production development module, the data sharing and web service module. Next, the user classification system and service content classification are introduced. The users are divided into five classes and the service content is divided into 4 layers. At last, the technology realization strategy and application in shipwreck salvation decision-making support system is introduced

A geographical information system for marine management and its application to Xiamen Bay, China

Use of GIS (geographical information systems) is an effective and efficient method for gathering and processing large quantities of marine data, such as three-dimensional (3-D) time series of velocity vectors and suspended sediment and pollutant concentrations, and for visual display for result interpretation. A MGIS (marine geographical information system) has been developed for Xiamen Bay and other coastal regions in China. The system can handle object spatial property and a variety of data formats. Besides the standard data manipulation, plotting, and retrieval functions of GIS, two hydrodynamic/mass-transport numerical models for tidal flows, sediment transport, and pollutant dispersion have also been incorporated into the MGIS. Most of the modeling pre- and post-processing operations can be finished within the system. The pre-processing includes mesh generation, gathering of boundary and parallel computation information. The post-processing includes result posting, plotting and analysis. The MGIS has been implemented for more than three years and proven to be a useful integrated tool for generating and revealing various kinds of marine environmental information. Output from the MGIS may provide an important tool for harbor management, and feasibility or environmental impact assessment studies for new coastal structures. The system can be easily adopted in other marine areas through loading new databases and re-verifying the numerical model in the new domain

The effect of cigarette price increase on the cigarette consumption in Taiwan: evidence from the National Health Interview Surveys on cigarette consumption

BACKGROUND: This study uses cigarette price elasticity to evaluate the effect of a new excise tax increase on cigarette consumption and to investigate responses from various types of smokers. METHODS: Our sample consisted of current smokers between 17 and 69 years old interviewed during an annual face-to-face survey conducted by Taiwan National Health Research Institutes between 2000 to 2003. We used Ordinary Least Squares (OLS) procedure to estimate double logarithmic function of cigarette demand and cigarette price elasticity. RESULTS: In 2002, after Taiwan had enacted the new tax scheme, cigarette price elasticity in Taiwan was found to be -0.5274. The new tax scheme brought about an average annual 13.27 packs/person (10.5%) reduction in cigarette consumption. Using the cigarette price elasticity estimate from -0.309 in 2003, we calculated that if the Health and Welfare Tax were increased by another NT$ 3 per pack and cigarette producers shifted this increase to the consumers, cigarette consumption would be reduced by 2.47 packs/person (2.2%). The value of the estimated cigarette price elasticity is smaller than one, meaning that the tax will not only reduce cigarette consumption but it will also generate additional tax revenues. Male smokers who had no income or who smoked light cigarettes were found to be more responsive to changes in cigarette price. CONCLUSIONS: An additional tax added to the cost of cigarettes would bring about a reduction in cigarette consumption and increased tax revenues. It would also help reduce incidents smoking-related illnesses. The additional tax revenues generated by the tax increase could be used to offset the current financial deficiency of Taiwan's National Health Insurance program and provide better public services

Red green blue emissive lead sulfide quantum dots: heterogeneous synthesis and applications.

Visible emission colloidal quantum dots (QDs) have shown promise in optical and optoelectronic applications. These QDs are typically composed of relatively expensive elements in the form of indium, cadmium, and gallium since alternative candidate materials exhibiting similar properties are yet to be realized. Herein, for the first time, we report red green blue (RGB) photoluminescences with quantum yields of 18% from earth-abundant lead sulfide (PbS) QDs. The visible emissive property is mainly attributed to a high degree of crystallinity even for the extremely small QD sizes (1-3 nm), which is realized by employing a heterogeneous reaction methodology at high growth temperatures (>170 °C). We demonstrate that the proposed heterogeneous synthetic method can be extended to the synthesis of other metal chalcogenide QDs, such as zinc sulfide and zinc selenide, which are promising for future industrial applications. More importantly, benefiting from the enlarged band gaps, the as-prepared PbS solar cells show an impressive open circuit voltage (∼0.8 V) beyond that reported to date

Consecutive junction-induced efficient charge separation mechanisms for high-performance MoS2/quantum dot phototransistors

Phototransistors that are based on a hybrid vertical heterojunction structure of two-dimensional (2D)/quantum dots (QDs) have recently attracted attention as a promising device architecture for enhancing the quantum efficiency of photodetectors. However, to optimize the device structure to allow for more efficient charge separation and transfer to the electrodes, a better understanding of the photophysical mechanisms that take place in these architectures is required. Here, we employ a novel concept involving the modulation of the built-in potential within the QD layers for creating a new hybrid MoS2/PbS QDs phototransistor with consecutive type II junctions. The effects of the built-in potential across the depletion region near the type II junction interface in the QD layers are found to improve the photoresponse as well as decrease the response times to 950 μs, which is the faster response time (by orders of magnitude) than that recorded for previously reported 2D/QD phototransistors. Also, by implementing an electric-field modulation of the MoS2 channel, our experimental results reveal that the detectivity can be as large as 1 × 1011 jones. This work demonstrates an important pathway toward designing hybrid phototransistors and mixed-dimensional van der Waals heterostructures

Enhanced charge carrier transport properties in colloidal quantum dot solar cells via organic and inorganic hybrid surface passivation.

Colloidal quantum dots (CQDs) are extremely promising as photovoltaic materials. In particular, the tunability of their electronic band gap and cost effective synthetic procedures allow for the versatile fabrication of solar energy harvesting cells, resulting in optimal device performance. However, one of the main challenges in developing high performance quantum dot solar cells (QDSCs) is the improvement of the photo-generated charge transport and collection, which is mainly hindered by imperfect surface functionalization, such as the presence of surface electronic trap sites and the initial bulky surface ligands. Therefore, for these reasons, finding effective methods to efficiently decorate the surface of the as-prepared CQDs with new short molecular length chemical structures so as to enhance the performance of QDSCs is highly desirable. Here, we suggest employing hybrid halide ions along with the shortest heterocyclic molecule as a robust passivation structure to eliminate surface trap sites while decreasing the charge trapping dynamics and increasing the charge extraction efficiency in CQD active layers. This hybrid ligand treatment shows a better coordination with Pb atoms within the crystal, resulting in low trap sites and a near perfect removal of the pristine initial bulky ligands, thereby achieving better conductivity and film structure. Compared to halide ion-only treated cells, solar cells fabricated through this hybrid passivation method show an increase in the power conversion efficiency from 5.3% for the halide ion-treated cells to 6.8% for the hybrid-treated solar cells