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991.
992.
In Situ Preparation of Sandwich MoO3/C Hybrid Nanostructures for High‐Rate and Ultralong‐Life Supercapacitors
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Hongmei Ji Xiaolin Liu Zhijuan Liu Bo Yan Lin Chen Yafeng Xie Chao Liu Wenhua Hou Gang Yang 《Advanced functional materials》2015,25(12):1886-1894
This work presents a design of sandwich MoO3/C hybrid nanostructure via calcination of the dodecylamine‐intercalated layered α‐MoO3, leading to the in situ production of the interlayered graphene layer. The sample with a high degree of graphitization of graphene layer and more interlayered void region exhibits the most outstanding energy storage performance. The obtained material is capable of delivering a high specific capacitance of 331 F g?1 at a current density of 1 A g?1 and retained 71% capacitance at 10 A g?1. In addition, nearly no discharge capacity decay between 1000 and 10 000 continuous charge–discharge cycles is observed at a high current density of 10 A g?1, indicating an excellent specific capacitance retention ability. The exceptional rate capability endows the electrode with a high energy density of 41.2 W h kg?1 and a high power density of 12.0 kW kg?1 simultaneously. The excellent performance is attributed to the sandwich hybrid nanostructure of MoO3/C with broad ion diffusion pathway, low charge‐transfer resistance, and robust structure at high current density for long‐time cycling. The present work provides an insight into the fabrication of novel electrode materials with both enhanced rate capability and cyclability for potential use in supercapacitor and other energy storage devices. 相似文献
993.
基于电信行业新增市场逐渐缩小,存量经营成为企业营销重点这一趋势,阐述了电信企业要实现数据驱动存量营销所需具备的条件以及目前尚存在的问题,并针对存量营销四大目标提出数据驱动存量营销发展策略建议:进行数据驱动存量营销IT系统的能力架构设计;梳理并建立电信企业存量营销运营管理流程;建立客户需求标签库和营销/策略资源库两个基础库;完善并建立需求资源配置、渠道触发和数据化管理三大存量营销核心能力. 相似文献
994.
In this study, we develop a system for interactive snow simulation and rendering. Snow is modeled as a hybrid structure that handles movable snow and static snow separately. We develop a simple approach to convert between these two types of snow. Movable snow is represented by a set of particles, whereas static snow is modeled as grid cells. For a piece of movable snow (e.g., snowflake), the particles are connected using springs. Thus, we can model snow as a type of brittle material, such as a snow pile split into chunks of smaller snow pieces after a collision. To render the snow, we adopt a shell structure that has a series of concentric, semitransparent, textured shells. We applied our system to several examples, with the rendered snow appearing similar to real snow. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
995.
Csaba M. Jzsa Gza Kolumbn Antonio M. Vidal Francisco J. Martínez‐Zaldívar Alberto Gonzlez 《Concurrency and Computation》2015,27(17):4993-5018
Multiple‐input multiple‐output (MIMO) systems have attracted considerable attention in wireless communications because they offer a significant increase in data throughput and link coverage without additional bandwidth requirement or increased transmit power. The price that has to be paid is the increased complexity of hardware components and algorithms. The sphere detector (SD) algorithm solves the problem of maximum likelihood (ML) detection for MIMO channels by significantly reducing the search space of possible solutions. The main drawback of the SD algorithm is in its sequential nature, consequently, running it on massively parallel architectures (MPAs) is very inefficient. In order to overcome the drawbacks of the SD algorithm, a new parallel sphere detector (PSD) algorithm is proposed. It implements a novel hybrid tree search method, where the algorithm parallelism is assured by the efficient combination of depth‐first search and breadth‐first search algorithms. A path metric‐based parallel sorting is employed at each intermediate stage. The PSD algorithm is able to adjust its memory requirements and extent of parallelism to fit a wide range of parallel architectures. Mapping details for MPAs are proposed by giving the details of thread dependent, highly parallel building blocks of the algorithm. Based on the building blocks proposed, a mapping to general‐purpose graphics processing unit is provided, and its performance is evaluated. In order to achieve high‐throughput, several levels of parallelism are introduced, and different scheduling strategies are considered. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
996.
Aidong Zeng Qingshan Xu Maosheng Ding Kazuto Yukita Katsuhiro Ichiyanagi 《IEEJ Transactions on Electrical and Electronic Engineering》2015,10(4):396-403
Storage devices are indispensable elements in a microgrid to compensate for the power imbalance between loads and the distributed generator (DG) output. Different storage strategies give diverse performances in adjustment speed and capacity. Based on the performance of different storage devices and the features of power imbalance curve in different periods, a classification control strategy is proposed in this paper. First, storage devices are given priorities according to the adjusting speed, and the power imbalance curve is divided into two periods according to the changing speed. During an emergency, all the storages are employed to compensate the rapidly increasing power imbalance; during the steady period, storage device with higher priority is employed to track the instantaneous component of power imbalance, while storage device with lower priority is used to replace the kWh output of higher priority storage. The proposed strategy is tested in a microgrid within the subdistribution network of IEEE RBTS Bus6 system using Monte Carlo methods. Simulation results indicate that the classification control strategy could endow the system with fast adjusting ability through coordination between storages. Reliability indices of the testing system are utilized to demonstrate that the classification control strategy could improve the stability of the microgrid and reliability of the distribution network. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. 相似文献
997.
Chawasak Rakpenthai Sermsak Uatrongjit 《IEEJ Transactions on Electrical and Electronic Engineering》2015,10(Z1):S19-S27
This paper presents a new hybrid state estimation method based on the concept of pseudo‐voltage measurements for a power system containing both conventional and synchronizing phasor measurements. Actual measurement data is employed to calculate the magnitude and phase of the pseudo‐voltage. In the proposed formulation, the measurement matrix describing the relations between the measured data and the state variables contains only 0 or 1. Then the state estimation problem is formulated based on the weighted least‐squares criterion, and its solution can be obtained without using iterative procedures. Comparisons with previous hybrid state estimation methods have been performed on IEEE 14‐bus, 57‐bus, and 118‐bus systems. Numerical experimental results indicate that the proposed approach yields solutions of comparable accuracy with other methods but with shorter computation times. Moreover, the proposed method also provides superior results in the presence of bad data. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. 相似文献
998.
Junyu Han Peter A. Crossley 《IEEJ Transactions on Electrical and Electronic Engineering》2015,10(4):383-389
Society is increasingly concerned about the environmental impact of energy systems, and prefers to locate power lines underground. This is especially true in regions of outstanding natural beauty or if they affect environmental/political/planning constrained areas. However, the use of underground sections within a predominantly overhead feeder introduces significant problems for the auto‐reclosure of circuit breakers. Auto‐reclosure is important on an overhead feeder, since most faults are transient and, once the feeder has been de‐energized, the insulation strength of the air at the fault recovers and the line can be restored to service. Faults on an underground cable are different because, once the insulation is damaged, the fault is normally permanent. In addition, if the breaker is allowed to reclose onto a cable fault, the area of damage increases and health and safety concerns exist for humans in the vicinity of the faulted cable section. The main purpose of the traveling‐wave‐based measurement scheme described in this paper is to locate a fault on a teed transmission feeder with mixed overhead and underground sections. Simulation results demonstrate that the fault locator can accurately locate all realistic faults, including ones that are high resistance or occur at nonideal points on wave. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. 相似文献
999.
The environmental justice movement attempts to examine the disproportionate exposure of environmental pollution on minority and low‐income people, understand the patterns of such disproportionate exposures and develop strategies to reduce and eliminate such exposures. Unlike several environmental justice studies that include all fifty states of the United States, this study examines the locations of manufacturing facilities that pollute in states with predominantly high African‐American populations. Our analysis indicates that polluting facilities tend to choose counties with higher proportion of nonwhite populations. Per capita incomes of people living within 5‐miles of the facilities are lower than per capita incomes of people living in the host counties Contrary to the conventional wisdom, population density per square mile both within 1 mile and 5 miles of the facility are much higher than the state population densities. 相似文献
1000.
Jacqueline Glass Corresponding author 《Construction Management & Economics》2013,31(2):169-184
The term ‘hybrid concrete construction’ (HCC) is used to describe the combination of concrete construction methods, e.g. in‐situ concrete and precast concrete, with one another or with other materials, e.g. steel. Although it could be argued that most buildings employ such combinations, HCC is the deliberate integration of different construction techniques to achieve a cost, speed or other performance benefit. UK government has been concerned that the construction industry suffers from poor management and exchange of tacit knowledge which can disappear after project teams ‘break up’. The completion of several innovative and high profile HCC projects was considered to be a major opportunity to capture project teams' tacit knowledge in this area. The objective of the research was to compile a best practice process model, such that project teams could be better informed as to their roles and responsibilities and thus be better equipped to deliver a building to the client's satisfaction, by using HCC. Interviews and knowledge capture workshops were used to extract lessons that lay embedded in both individuals and teams. The main conclusions were that successful HCC projects were characterized for example, by the development of an ethos of trust, the early involvement of specialists (such as precasters) and the effective management of both tacit and explicit knowledge. The research builds on previous work in the area by identifying best practice information on design, specification and construction factors for HCC and, in addition, some transferable lessons on knowledge capture techniques. 相似文献