基于半光滑牛顿法的可用输电能力新算法

提出了计算电网可用输电能力(ATC)的一种新方法。将ATC计算问题描述为特定发电节点与负荷节点的交易量最大的优化问题,考虑了多种系统运行约束和交易规则约束。针对这一优化问题,通过引入非线性互补问题函数,将原优化问题转化为非线性方程组,并采用半光滑牛顿法进行求解。算法的显著优点是避免了不等式约束的识别问题,从而极大地提高了计算效率。IEEE系统的多个算例表明该方法非常有效,具有很好的应用前景。     

Conjectural variation based learning model of strategic bidding in spot market

In actual electricity market, which operates repeatedly on the basis of one hour or half hour, each firm might learn or estimate other competitors' strategic behaviors from available historical market operation data, and rationally aims at its maximum profit in the repeated biddings. A conjectural variation based learning method is proposed in this paper for generation firm to improve its strategic bidding performance. In the method, each firm learns and dynamically regulates its conjecture upon the reactions of its rivals to its bidding according to available information published in the electricity market, and then makes its optimal generation decision based on the updated conjectural variation of its rivals. Through such learning process, the equilibrium reached in the market is proven a Nash equilibrium. Motivation of generation firm to learn in the changing market environment and consequence of learning behavior in the market are also discussed through computer tests.     

输电系统固定成本分摊问题

在电力市场环境下，输电固定成本需要公平、合理地分摊给所有电网使用者。合理的分摊方法可以引导对现有输电设备的有效和合理的使用，并为将来的发电规划和负荷选址提供经济信号。文中对现有的输电固定成本分摊方法进行了全面而系统的综述，按照所分摊的成本、承担成本的主体、所基于的系统状态、冗余容量成本的分摊、对反向潮流的收费、对无功功率的处理、分摊的原则与方法等方面，对现有的输电成本分摊方法进行了详细的分析，论述了每一种方法的特点，并对各种方法进行了比较和讨论。     

Light‐Controlled,High‐Resolution Patterning of Living Engineered Bacteria Onto Textiles,Ceramics, and Plastic

Living cells can impart materials with advanced functions, such as sense‐and‐respond, chemical production, toxin remediation, energy generation and storage, self‐destruction, and self‐healing. Here, an approach is presented to use light to pattern Escherichia coli onto diverse materials by controlling the expression of curli fibers that anchor the formation of a biofilm. Different colors of light are used to express variants of the structural protein CsgA fused to different peptide tags. By projecting color images onto the material containing bacteria, this system can be used to pattern the growth of composite materials, including layers of protein and gold nanoparticles. This is used to pattern cells onto materials used for 3D printing, plastics (polystyrene), and textiles (cotton). Further, the adhered cells are demonstrated to respond to sensory information, including small molecules (IPTG and DAPG) and light from light‐emitting diodes. This work advances the capacity to engineer responsive living materials in which cells provide diverse functionality.     

Nearly room-temperature type-II quantum-well lasers at 3–4 μm

We report optically pumped four-constituent InAs/InGaSb/InAs/AlSb type-II quantum-well lasers emitting at 3.2–4.1 μm. Lasing was observed up to 350K under pulsed operation, with a characteristic temperature T₀ up to 68K at temperatures above ambient.     

Heuristic algorithms for the fiber optic network expansion problem

We consider a network expansion problem for fiber optic networks. Given the network topology, edge costs, and node profit per period, the network is built over T periods due to limited budget available per period. The problem is to find edges to be added at each period so that their edge cost does not exceed the budget limit and the resulting network is connected, with the objective of maximizing profit over T periods. We first consider some special graphs: lines, cycles, and trees. Then we show that NEP is strongly NP‐complete for general graphs, and present three heuristic algorithms and their performance analyses. Computational results show evidence that the simple greedy algorithm performs very effectively for finding a near optimal solution. This revised version was published online in June 2006 with corrections to the Cover Date.     

High-temperature 4.5-/spl mu/m type-II quantum-well laser with Auger suppression

Laser emission at 4.2-4.5 /spl mu/m has been observed at temperatures up to 310 K in pulsed optical pumping experiments on type-II quantum-well (QW) lasers with four constituents in each period (InAs-Ga/sub 1-x/In/sub x/Sb-InAs-AlSb). The characteristic temperature, T/sub 0/, is 41 K, and a peak output power exceeding 2 W/facet is observed at 200 K. The power conversion efficiency per facet of /spl ap/0.2% up to 200 K is within a factor of 2 of the theoretical value. The 300 K Auger coefficient of 4/spl times/10/sup -27/ cm/sup 6//s extracted from the threshold pump intensity demonstrates that Auger losses have been suppressed by a factor of four.     

High‐Performance n‐Channel Thin‐Film Field‐Effect Transistors Based on a Nanowire‐Forming Polymer

A new electrontransport polymer, poly{[N,N′‐dioctylperylene‐3,4,9,10‐bis(dicarboximide)‐1,7(6)‐diyl]‐alt‐[(2,5‐bis(2‐ethyl‐hexyl)‐1,4‐phenylene)bis(ethyn‐2,1‐diyl]} (PDIC8‐EB), is synthesized. In chloroform, the polymer undergoes self‐assembly, forming a nanowire suspension. The nanowire's optical and electrochemical properties, morphological structure, and field‐effect transistor (FET) characteristics are investigated. Thin films fabricated from a PDIC8‐EB nanowire suspension are composed of ordered nanowires and ordered and amorphous non‐nanowire phases, whereas films prepared from a homogeneous PDIC8‐EB solution consist of only the ordered and amorphous non‐nanowire phases. X‐ray scattering experiments suggest that in both nanowires and ordered phases, the PDIC8 units are laterally stacked in an edge‐on manner with respect to the film plane, with full interdigitation of the octyl chains, and with the polymer backbones preferentially oriented within the film plane. The ordering and orientations are significantly enhanced through thermal annealing at 200 °C under inert conditions. The polymer film with high degree of structural ordering and strong orientation yields a high electron mobility (0.10 ± 0.05 cm² V^?1 s^?1), with a high on/off ratio (3.7 × 10⁶), a low threshold voltage (8 V), and negligible hysteresis (0.5 V). This study demonstrates that the polymer in the nanowire suspension provides a suitable material for fabricating the active layers of high‐performance n‐channel FET devices via a solution coating process.     

Unavailability due to rain of VSAT networks operating in Ka and Ku bands in Brazil

The unavailability due to rain of VSAT star networks operating on Ku and Ka bands in Brazil is analysed in this paper. A large number of simulations performed over the Earth–space links resulting from combinations of four (real and hypothetical) satellites with six Brazilian Earth stations provide a good characterization of the rain unavailability in tropical and equatorial regions subject to heavy rainfall and thunderstorms. The simulations also compare the influence on the estimated unavailability of the use of two different ITU‐R rain attenuation models and two values (calculated and measured) for the rainfall rate exceeded during 10^?2% of the time, the climatic parameter in the models, in addition to the link polarization employed. The results obtained point to VSAT star networks as a practical solution to provide telecommunications services to remote communities. Copyright © 2006 John Wiley & Sons, Ltd.