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排序方式: 共有73条查询结果,搜索用时 31 毫秒
1.
国内风电和光伏等新能源发电迅速发展,而部分地区本地消纳和电网外送能力均有限,当地自备电厂未充分发挥调峰作用,出现日趋严重的弃风弃光现象,因此难以完成配额制目标。为利用市场手段充分调动当地自备电厂参与新能源消纳,促进新能源配额制目标的完成,同时避免因强行完成指标导致的社会整体消纳成本升高的问题,提出了一种基于竞价摘牌的新能源日前交易模式。通过具有引导效应的市场化手段,调动具备自备电厂用户的主动消纳意愿,进而提升配额制目标完成度,并降低整体消纳成本。最后,以新疆地区算例为例,分析验证了所提交易模式在提升配额制目标完成度及在尽量降低社会整体消纳成本方面的价值,为新疆等类似地区电力市场建设提供了一种新的思路。 相似文献
2.
李伟 《中国图象图形学报》2003,8(1):105-109
目前视频图象在 IP分组网中的传输正被日益广泛地应用 (如 :视频电话、视频会议 ) .但是 ,由于 IP分组网固有的特点 ,致使 IP分组包丢失的现象不可避免 ,并极大地影响了视频传输的服务质量 .由于参考图象选择法RPS(Reference Picture Selection)是一种较好的视频图象差错复原的方法 ,因此 ,为了改善因分组包丢失而对视频传输带来的质量下降问题 ,利用 RTCP协议提供反馈信息和利用参考图象选择法进行视频图象复原 ,实现了一种在 IP分组网中进行视频传输的差错控制机制 .实践证明 ,通过这种方法不仅可减小因分组包丢失而对视频图象信息带来的损害 ,而且可提高视频图象的传输质量 ,此方法适用于基于分组网的视频传输系统 . 相似文献
3.
H. R. Williams R. M. Ambrosi N. P. Bannister P. Samara‐Ratna J. Sykes 《国际能源研究杂志》2012,36(12):1192-1200
Spacecraft venturing to the outer planets and beyond—or onto the planetary surface where available solar energy is reduced—benefit from the longevity and consistency of electrical and thermal energy derived from radioisotope energy sources. A review of likely mission requirements and concept studies of small electrical generating units (<10 We) reveals a potential opportunity for a unit with an electrical output of around 1 We that can also supply some heat to the spacecraft to aid thermal control: a radioisotope thermoelectric and heating unit. This power requirement cannot be achieved with current US space‐qualified modular radioisotope fuel assemblies. Additionally, new European programmes consider 241Am fuel to be much more cost effective than 238Pu. Taken together, these factors provide the rationale for taking a relatively ‘clean‐sheet’ approach to design of a radioisotope thermoelectric and heating unit fuelled with 241Am. In this paper, initial requirements and performance targets for such a unit are developed, a simple concept design and thermal model is presented and the performance and mass are estimated. The results suggest that units generating 1–2 We may achieve a specific power of around 0.7–0.9 We kg?1 without the thermal inputs to spacecraft becoming impractically large. Such units can use a bismuth telluride thermoelectric material, which is commercially applied in terrestrial applications and is therefore likely to incur lower cost and development risk than more specialised compounds. This study may form the basis of a more detailed design effort. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
4.
Yong Yang Dianran YanYanchun Dong Lei WangXueguang Chen Jianxin ZhangJining He Xiangzhi Li 《Journal of Alloys and Compounds》2011,509(5):L90
In situ nanostructured ceramic matrix composite coating was prepared by reactive plasma spraying micro-sized Al-Fe2O3 composite powders. The microstructure of the composite coating was characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy, respectively. The results indicated that the composite coating exhibited dense and crack-free microstructure with a number of spherical α-Fe and γ-Al2O3 nano-grains embedded within equiaxed and columnar FeAl2O4 nano-grains matrix. The composite coating showed markedly higher toughness and wear resistance than the conventional Al2O3 coating. 相似文献
5.
T. Czibk Z. Dezs Cs. Horvth S. Lipcsei J. Vgh I. Ps 《Nuclear Engineering and Design》2006,236(22):2356-2364
In 2004 the Hungarian Paks NPP completed a project for upgrading the reactivity measuring system applied during reactor startup experiments. Almost all components of the previous system were replaced, only ex-core ionisation chambers remained unaltered. New hardware and software components were introduced for neutron flux signal handling, for data acquisition, as well as for measurement evaluation and data presentation. High-precision picoamper meters were installed at each reactor unit, current signals are handled by a portable signal processing unit. The system applies an accurate on-line reactivity calculation algorithm based on the point-kinetic model with six delayed neutron groups. Detailed off-line evaluation and analysis of startup measurements can be performed on the portable unit, as well.The paper describes the architecture, data acquisition modules, services and man–machine interface of the new system. Functions and results are illustrated with measured data recorded during a startup of Unit 3. In 2003 and 2004 the RMR was installed and tested at all Paks NPP units successfully and now it is in regular use during unit startups.The second part of the paper illustrates an extension of the new system to perform reactivity measurements using the well-known Rossi-α and Feynman-α statistical methods. The modified system was needed to estimate the reactivity of a subcritical system formed by damaged fuel assemblies stored at the fuel service pit of Paks Unit 2. Theoretical background of the applied algorithms is outlined, then results of validation tests and on site measurements are treated. The measurements have shown that the subcriticality of the damaged fuel was sufficiently deep if the high boron concentration in the fuel service pit was maintained. 相似文献
6.
7.
To avoid plasma induced erosion of chamber hardware, the application of remote plasma sources to activate the etch gases was introduced. We present results on the etch behaviour of titanium nitride (TiN) using mixtures of NF3, Cl2 and argon. The gas mixture was excited in a remote plasma source and then routed through a reaction chamber to study the etch behaviour of TiN samples which simulate the situation at the chamber walls. The dependency of the TiN etch rate on temperature, gas flow, composition and pressure was examined. While the temperature (studied in the range 25-300 °C) turned out to be the most sensitive parameter, the general etch rate was mainly dependent on the availability of atomic fluorine. Etch products and NF3/Cl2 dissociation have been monitored by quadrupole mass spectrometry and infrared spectroscopy. While NF3 showed a high decomposition up to 96%, chlorine decomposition was not observed. However the addition of chlorine increased the etch rates up to 260% in the low pressure/low temperature regime. Surface effects of chlorine addition are indicated by X-Ray Photoelectron Spectrometry and REM surface analysis. 相似文献
8.
This study investigated factors influencing the adoption or intention to adopt renewable portfolio standards (RPS) by individual states in the United States (U.S). Theory of adoption of innovation was applied as a conceptual framework. A logistic model was used to achieve the task. Gross state product (GSP), growth rate of population (GRP), political party dominancy, education level, natural resources expenditure, and share of coal in electricity generation were used as explanatory variables. Results indicated that the model predicts the dependent variable (state's choice of adopting or not adopting RPS) 82 times correctly out of 100. Results also suggested that education followed by political party dominancy, GSP and GRP are shown to have large impacts on the probability of RPS adoption. 相似文献
9.
针对三电平逆变器交叉两桥臂的两只功率管同时开路故障(非典型故障)诊断问题,提出一种基于相空间重构和支持向量机(SVM)的故障诊断方法。该方法以三相电流为检测信号,为降低特征向量的维数,对三相电流进行了Park变换,然后采用相空间重构技术,对d、q轴电流分别进行重构,得到不同形状、大小和方向的电流轨迹图形,借助图像处理技术从中提取出故障特征向量,将其作为学习样本,在SVM中训练,使分类器能够建立不同特征向量和故障类型的映射关系,实现对二极管中点箝位型(NPC)三电平逆变器的故障诊断。仿真结果表明,该方法能够准确地定位故障元,诊断精度高。 相似文献
10.