清洁电力行动——由化石能源转向清洁能源

1电力行业的碳零排放之路燃烧煤、石油和天然气等化石燃料所排放的二氧化碳在大气层中不断积累,像毛毯一样包裹着地球,使热量聚集,导致全球气候变暖。很多证据表明,全球气候变化是目前人类所面临的波及范围最广的环境问题。它将对野生动植物栖息地、生物多样性、粮食供应、经济     

Introduction to the special issue on IEEE NEWCAS 2017

A contactless detector is presented for evaluating hand tremors caused by exercise-induced fatigue and early Parkinson’s disease. The device consists of a spiral coil, a microcontroller, and an inductive sensor circuitry. Theory shows that the resonant frequency of the circuitry increases when the distance between the hand and the spiral coil decreases, thus small variations of distance from tremor can be detected from the changes of resonant frequencies. A mechanical hand was built for experiments to simulate human hand tremors with repeatability at a fixed frequency. The magnitudes and frequencies of the tremors in the mechanical hand were quantitatively identified using the inductive sensor. Hence, feasibility and accuracy of the contactless hand tremor detector were determined. A triaxial accelerometer was used for comparison. By comparing spectral distributions and magnitudes of the tremors, the inductive sensor performed better than the accelerometer. The detector was applied to evaluate actual hand tremors of three subjects who had undergone exercise to induce tremors. The tremor waveform amplitudes of the subjects were quantitatively analyzed by the standard deviations method. The increased signal energies of exercise-induced tremor within 8–12 Hz were confirmed. Then, a subject with early Parkinson’s disease was evaluated by the proposed hand tremor detector. The tremor magnitudes and frequencies of the patient hand were quantitatively identified within in 4–7 Hz. Therefore, the new contactless hand tremor detector can be developed as a clinical instrument for monitoring the fatigue symptoms of post-exercise and diagnosing the early Parkinson’s disease.     

Associations Between Message Features and Subjective Evaluations of the Sensation Value of Antidrug Public Service Announcements

The effective targeting of high sensation-seeking adolescents, who are most at risk for drug abuse, requires the creation of high sensation value messages. Whereas previous research has focused on subjective reactions of receivers as the primary way to define message sensation value (MSV), we conceptualize message sensation value as the formal and content features (audio, visual, and format) of a message that contribute to subjective message sensation evaluations. The three objectives of this study were (a) to identify message design features that would aid in the development of effective prevention messages targeting high sensation seekers, (b) to develop an objective measure of message sensation value based on formal and content features of messages, and (c) to determine whether high message sensation value messages were associated with higher subjective evaluations of message sensation value. In the present study, 418 undergraduates each viewed 10 PSAs selected at random from a pool of 109 PSAs that had been previously coded for message sensation value. Analyses provide support for the central hypothesis of the study, indicating that perceived message sensation value is at least in part a product of the formal and content features of a PSA.     

Multi‐Material Tissue Engineering Scaffold with Hierarchical Pore Architecture

Multi‐material polymer scaffolds with multiscale pore architectures are characterized and tested with vascular and heart cells as part of a platform for replacing damaged heart muscle. Vascular and muscle scaffolds are constructed from a new material, poly(limonene thioether) (PLT32i), which meets the design criteria of slow biodegradability, elastomeric mechanical properties, and facile processing. The vascular–parenchymal interface is a poly(glycerol sebacate) (PGS) porous membrane that meets different criteria of rapid biodegradability, high oxygen permeance, and high porosity. A hierarchical architecture of primary (macroscale) and secondary (microscale) pores is created by casting the PLT32i prepolymer onto sintered spheres of poly(methyl methacrylate) (PMMA) within precisely patterned molds followed by photocuring, de‐molding, and leaching out the PMMA. Prefabricated polymer templates are cellularized, assembled, and perfused in order to engineer spatially organized, contractile heart tissue. Structural and functional analyses show that the primary pores guide heart cell alignment and enable robust perfusion while the secondary pores increase heart cell retention and reduce polymer volume fraction.     

An Open Grid Services Architecture Primer

To expand the use of distributed computer infrastructures as well as facilitate grid interoperability, OGSA has developed standards and specifications that address a range of scenarios, including high-throughput computing, federated data management, and service mobility.     

The Transition to Solid-State Lighting

Lighting constitutes more than 20% of total U.S. electricity consumption, a similar fraction in the European Union, and an even higher fraction in many developing countries. Because many current lighting technologies are highly inefficient, improved technologies for lighting hold great potential for energy savings and for reducing associated greenhouse gas emissions. Solid-state lighting shows great promise as a source of efficient, affordable, color-balanced white light. Indeed, assuming market discount rates, engineering-economic analysis demonstrates that white solid-state lighting already has a lower levelized annual cost (LAC) than incandescent bulbs. The LAC for white solid-state lighting will be lower than that of the most efficient fluorescent bulbs by the end of this decade. However, a large literature indicates that households do not make their decisions in terms of simple expected economic value. After a review of the technology, we compare the electricity consumption, carbon emissions, and cost-effectiveness of current lighting technologies, accounting for expected performance evolution through 2015. We then simulate the lighting electricity consumption and implicit greenhouse gases emissions for the U.S. residential and commercial sectors through 2015 under different policy scenarios: voluntary solid-state lighting adoption, implementation of lighting standards in new construction, and rebate programs or equivalent subsidies. Finally, we provide a measure of cost-effectiveness for solid-state lighting in the context of other climate change abatement policies.     

Individual and situational factors that influence the efficacy of personalized feedback substance use interventions for mandated college students.

Little is known about individual and situational factors that moderate the efficacy of personalized feedback interventions (PFIs). Mandated college students (N = 348) were randomly assigned either to a PFI delivered in the context of a brief motivational interview (BMI; n = 180) or to a written PFI only (WF) condition and were followed up at 4 months and 15 months postintervention. The authors empirically identified heterogeneous subgroups utilizing mixture modeling analysis based on heavy episodic drinking and alcohol-related problems. The 4 identified groups were dichotomized into an improved group (53.4%) and a nonimproved group (46.6%). Logistic regression results indicated that the BMI was no more efficacious than the WF across all mandated students. However, mandated students who experienced a serious incident requiring medical or police attention and those with higher levels of alcohol-related problems at baseline benefited more from the BMI than from the WF. It may be an efficacious and cost-effective approach to provide a written PFI for low-risk mandated students and an enhanced PFI with a BMI for those students who experience a serious incident or have higher baseline alcohol-related problems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Variable toroidal ferrite phase shifter

Careful design of the magnetic bias circuit used in ferrite phase shifters can help to reduce space, weight and energy consumption. Low reluctance circuits must avoid air-gaps and this can be achieved using toroidal-shaped ferrite inserts positioned inside a rectangular waveguide. Here, these ferrite inserts are fabricated using a viscous plastic processing method that avoids machining and produces a continuous magnetic circuit. Finite-element methods are used to initially model the magnetostatic solution for the bias circuit before being used to analyse the microwave performance of a double toroid phase shifter. A closedform technique is introduced to model the dielectric slab waveguide impedance transformer. The final insertion loss was ,1 dB over the 9.5?10.3 GHz band and return loss of 20 dB was achievable. The phase shift calculation agrees to within 10% of the measured values.