Carbonization over PFA-protected dispersed platinum: An effective route to synthesize high performance mesoporous-carbon supported Pt electrocatalysts

An alternative and effective route of synthesizing mesoporous carbon supported Pt nanoparticles is introduced. In reverse order to the conventional synthetic route, carbonization occurs after dispersion of platinum. In this process, H2PtCl6 acts as a Pt source and also serves as a catalyst for the polymerization of furfuryl alcohol (FA). The polymerized FA around the H2PtCl6 nanoparticles functions as a protecting agent and prevents the growth of Pt nanoparticles in the later high temperature carbonization step. The resulting Pt nanoparticles are highly dispersed in the mesoporous carbon structure, CMK3, and give a much higher methanol oxidation current when compared with Pt/CMK3 electrocatalysts prepared via the conventional route. © The Royal Society of Chemistry 2011.postprin

Electrochemical capacitance and ionic transport in the mesoporous shell of a hierarchical porous core-shell carbon structure

A three-dimensional (3D) hierarchical porous carbon structure was prepared with possible variations in porosity at three levels of length scales. The carbon structure was template-synthesized from a core-shell silica sphere assembly. The as-synthesized carbon featured a semi-ordered porous structure with hollow macro-cores (330 nm) surrounded by a mesoporous shell containing uniform pores of 3.9 nm and distinct interstitial space between the core-shell domains. The mesoporous shell thickness was stepwise increased from 0, 25, 50 to 100 nm while keeping an identical core size to create a family of hierarchical porous structures for a systematic investigation of electrochemical capacitance and ionic transport. The shell thickness affected the overall porosity and relative porosities of the shell, core, and interstitial regions. A thicker mesoporous shell possessed a higher surface area which led to a proportional increase in electrochemical capacitance which can be fully realised at low scan rates. For the carbon structure with the maximum shell thickness of 100 nm, electrochemical capacitance per unit area and power density declined at high scan rates and high currents when ionic transport through long mesopores became limiting. The power density of the better as-synthesized porous carbon was up to 11.7 kW kg-1 when the corresponding energy density was 5.9 W h kg-1. © 2011 The Royal Society of Chemistry.postprin

A room temperature indirect formic acid fuel cell

Session B-1.2: Vehicle, Gas Processing/Storage, Direct-Fuel FCspublished_or_final_versionThe 218th Meeting of the Electrochemical Society (ECS Meeting 2010), Las Vegas, NV., 10-15 October 2010. In Electrochemical Society Meeting Abstracts, 2010, abstract 67

Finding diamonds in the rough: Targeted Sub-threshold Search for Strongly-lensed Gravitational-wave Events

Strong gravitational lensing of gravitational waves can produce duplicate signals separated in time with different amplitudes. We consider the case in which strong lensing produces identifiable gravitational-wave events and weaker sub-threshold signals hidden in the noise background. We present a search method for the sub-threshold signals using reduced template banks targeting specific confirmed gravitational-wave events. We apply the method to all events from Advanced LIGO's first and second observing run O1/O2. Using GW150914 as an example, we show that the method effectively reduces the noise background and raises the significance of (near-) sub-threshold triggers. In the case of GW150914, we can improve the sensitive distance by $2.0\% - 14.8\%$. Finally, we present the top $5$ possible lensed candidates for O1/O2 gravitational-wave events that passed our nominal significance threshold of False-Alarm-Rate $\leq 1/30$ days

Predicting athletes’ pre-exercise fluid intake: A theoretical integration approach

Pre-exercise fluid intake is an important healthy behavior for maintaining athletes’ sports performances and health. However, athletes’ behavioral adherence to fluid intake and its underlying psychological mechanisms have not been investigated. This prospective study aimed to use a health psychology model that integrates the self-determination theory and the theory of planned behavior for understanding pre-exercise fluid intake among athletes. Participants (n = 179) were athletes from college sport teams who completed surveys at two time points. Baseline (Time 1) assessment comprised psychological variables of the integrated model (i.e., autonomous and controlled motivation, attitude, subjective norm, perceived behavioral control, and intention) and fluid intake (i.e., behavior) was measured prospectively at one month (Time 2). Path analysis showed that the positive association between autonomous motivation and intention was mediated by subjective norm and perceived behavioral control. Controlled motivation positively predicted the subjective norm. Intentions positively predicted pre-exercise fluid intake behavior. Overall, the pattern of results was generally consistent with the integrated model, and it was suggested that athletes’ pre-exercise fluid intake behaviors were associated with the motivational and social cognitive factors of the model. The research findings could be informative for coaches and sport scientists to promote athletes’ pre-exercise fluid intake behaviors

Impacts of Ti content and annealing temperature on electrical properties of Si MOS capacitors with HfTiON gate dielectric

Proceedings of the IEEE International Conference of Electron Devices and Solid-State Circuits, 2009, p. 221-224HfTiON gate dielectric is fabricated by reactive co-sputtering method followed by annealing in N 2 ambient. The effects of Ti content and annealing temperature on the performances of HfTiON gate-dielectric Si MOS devices are investigated. Experimental results indicate that gate capacitance is increased with increasing Ti content. However, when the Ti/Hf ratio exceeds -1.75, increase of the gate capacitance becomes small. Surface roughness of the samples annealed at different temperatures is analyzed by AFM, and results show that high annealing temperature (e.g. 700 °C for 30 s) can produce smooth surface, thus resulting in low gate leakage current. ©2009 IEEE.published_or_final_versio

Level Set Method for Positron Emission Tomography

In positron emission tomography (PET), a radioactive compound is injected into the body to promote a tissue-dependent emission rate. Expectation maximization (EM) reconstruction algorithms are iterative techniques which estimate the concentration coefficients that provide the best fitted solution, for example, a maximum likelihood estimate. In this paper, we combine the EM algorithm with a level set approach. The level set method is used to capture the coarse scale information and the discontinuities of the concentration coefficients. An intrinsic advantage of the level set formulation is that anatomical information can be efficiently incorporated and used in an easy and natural way. We utilize a multiple level set formulation to represent the geometry of the objects in the scene. The proposed algorithm can be applied to any PET configuration, without major modifications

The Consequences of Information Technology Control Weaknesses on Management Information Systems: The Case of Sarbanes-Oxley Internal Reports

In this paper, we investigate the association between the strength of information technology controls over management information systems and the subsequent forecasting ability of the information produced by those systems. The Sarbanes-Oxley Act of 2002 highlights the importance of information system controls by requiring management and auditors to report on the effectiveness of internal controls over the financial reporting component of the firm’s management information systems. We hypothesize and find evidence that management forecasts are less accurate for firms with information technology material weaknesses in their financial reporting system than the forecasts for firms that do not have information technology material weaknesses. In addition, we find that this association appears to be driven by control weaknesses most directly related to data processing integrity. Our results support the contention that information technology controls, as a part of the management information system, affect the quality of the information produced by the system

Analyzing the deformation of multilayered saturated sandy soils under large building foundation

The generalized plasticity theory has been subject of much research in geomechanics. The Pastor-Zienkiewicz model and its modified versions are among these. For large foundations resting on multilayered soils the actual loading is often non-linear. In this study we developed a new mathematical model which can apply non-linear loading using the subfield of planar mesh method. A sensitivity study was first performed to evaluate the contribution of deformation from various model parameters. It is found that the plastic modulus parameters only have marginal contributions. An engineering case study was used to valid the proposed model and it is evident from measured stresses that the loading of the foundation is non-linear. The deformations calculated by the proposed model agreed well with the monitored deformations. It is also found that the maximum deformation point is not necessarily in the centre of foundation and it does not coincide with the maximum loading point either. The distance between the maximum deformation point and the maximum loading point can be as far as 15.59 m for the bottom layer soil from this case. This research proves the necessity of using non-linear loading to calculate the foundation deformations for large foundations with multilayered saturated soils. Keywords:large building foundation; Pastor-Zienkiewicz model; sensitivity analysis; foundation deformation; multilayered soil