大规模并行处理系统互连通信的新技术研究

本文综述了大规模并行处理系统研究了工作的概况，指出其研究热点和关键技术是实现高效的互连通信。文中重点介绍了该领域的研究内容：结点结构、网络接口、切换技术，拓扑结构，路由算法，通信机制，通信协议，计算模型等。     

On evaluating the effects of the incident angle on the energy harvesting performance and MPP estimation of PV modules

The incident angle is a critical factor impacting the performance of fixed photovoltaic (PV) modules. Off‐normal incidence leads to significant changes in the current–voltage (I–V) characteristics and serious deterioration in the performance of fixed PV modules, resulting in difficulties in achieving optimal use of the available solar energy and retaining the maximum power output. To investigate this problem in depth, we develop a theoretical method based on the material properties and recombination mechanisms of the semiconductor, which can be used to directly evaluate the incident angle dependence of the energy harvesting performance and the maximum power point (MPP) estimation of PV modules composed of different materials from their I–V characteristic curves under irradiation. The proposed method is a simple approach with a low calculation burden. The performance of the proposed method is evaluated by examining the characteristics of the open‐circuit voltage, short‐circuit current, MPP, and the maximum output power of PV modules constructed of different semiconductor materials with respect to the various incident angles. The results are discussed in detail. The experimental results demonstrate that the proposed method could be used to optimize the performance of fixed PV modules and realize MPP control of PV systems during practical operation. Copyright © 2013 John Wiley & Sons, Ltd.     

FC energy harvesting using the MPP tracking based on advanced extremum seeking control

In this paper is proposed a Maximum Power Point (MPP) tracking technique for the Fuel Cell (FC) stacks based on advanced Extremum Seeking (aES) control that improves the basic performances of the ES control schemes: a guaranteed convergence and proved internal robustness. Other features such as higher search speed and improved tracking accuracy are demonstrated for the proposed aES control, besides these features that are necessary in case of unmodeled dynamics. The analysis on the frequency domain reveals the relationships between the main aES control parameters, the values of closed loop gain and dither amplitude, and the design performance indicators, the speed of search and accuracy of MPP finding, respectively. If the dither amplitude is set to be proportional with the magnitude of first harmonics of the processed FC power, then the reference current used in the FC current control loop will have an insignificant ripple after the MPP is caught. Thus, a reduced FC power ripple will appear. Therefore, if the search speed is set to be the same for all ES control schemes, then the proposed aES control outperforms all classical ES control schemes in overall power efficiency. Moreover, the aES search speed will proportionally increase with the loop gain and the dither amplitude. Note that here the dither has the amplitude set by the first harmonic of the FC power, being a time variable that have high value during the searching phase. This accelerates MPP searching up to the FC safe limits. Finally, this means a controllable time to shortly find the next MPP on dynamical operation of the FC stack. First harmonic of the FC power becomes almost zero after MPP is caught. Thus, higher tracking accuracy that means an economy on fuel consumption is obtained. The simulations performed show that above mentioned performances are effective for the aES control operating in both ripple- and dither-based modes of the grid connected FC inverters.     

膨胀型阻燃剂PEPA/MPP阻燃LGFPP性能研究

将季戊四醇磷酸酯(PEPA)和三聚氰胺聚磷酸盐(MPP)复配成一种膨胀型阻燃剂(IFR),用于对长玻纤增强聚丙烯(LGFPP)进行阻燃。采用极限氧指数测试、垂直燃烧测试、扫描电子显微镜观察、热重分析、力学性能测试等方法探讨了该IFR组成对LGFPP的阻燃性能、热稳定性能以及力学性能的影响。结果表明,IFR的总添加量为20%,当PEPA与MPP质量比为11∶9时,复配阻燃效果最佳,阻燃LGFPP的极限氧指数值为26.1%,UL–94燃烧等级达到V–0级;生成的炭层致密、连续性好且稳定;阻燃LGFPP表现出较好的热稳定性与力学性能。     

运营商发展大数据技术及建设模式展望

首先分析了互联网企业和国外运营商发展大数据的情况,接着结合大数据技术发展特性,对运营商大数据平台的架构和建设模式提出了建设思路,最后对大数据未来进行展望。     

运营商省级大数据体系建设方案研究

运营商大数据体系建设是适应运营转型,对内提升运营效率,对外拓展市场的重要举措;虽然运营商已有较长的数据管理经验,但大数据体系建设还处在初级阶段;因此,在体系建立过程中,不仅要关注IT平台建设和数据的统一融合,还要有配套的大数据运营管理手段;本文结合现阶段建设需求,给出了省级大数据系统建设的技术方案和运营演进思路。     

膨胀阻燃聚丙烯的研究

研究了淀粉、季戊四醇等对PP/阻燃剂体系的膨胀阻燃效果的影响。根据膨胀阻燃原理,合成了一种多功能的新型膨胀阻燃剂MPP,同时利用IR、TGA等手段对合成的膨胀阻燃剂的结构、热稳定性及其在PP中的阻燃效果进行了研究     

Mechanical/structural reliability evaluation through Esscher''s method of approximation

A simple and effective computational procedure is presented for computing probabilities of failure of mechanical and structural systems. The method provides very close approximate solutions for well behaved linear limit state functions with independent normal or nonnormal, continuous or discrete random variables. But the random variables should have moment generating functions. This method is also applicable when the limit state function is a hyper sphere. Numerical examples are given including one for hyper sphere limit state.     

Evaluation of performance of photovoltaic system with maximum power point (MPP)

Performance of the photovoltaic system is highly influenced by the weather, especially the irradiation and the temperature. To simplify the design of solar generator power, a mathematical model and its validity of the solar cell are required. In this work, the value of the parameters in the mathematical model is obtained by the measurement of the I–V curve of the module. To get an I–V curve, one of the modules in the system was radiated and loaded by a load simulator. A photovoltaic pumping system with maximum power point tracker was built and tested. The results were analyzed and evaluated by using the parameters and the photovoltaic system was shown to be well optimized.     

Deposition rate characteristics for steady state high power impulse magnetron sputtering (HIPIMS) discharges generated with a modulated pulsed power (MPP) generator

High power impulse magnetron sputtering (HIPIMS) pulses have been of great interest over the last decade. With such sputtering techniques a substantial amount of target material can be ionized and used for the engineering of surfaces and coatings. Depending on voltage, system configuration and target material, such discharges can be either transient or reach steady state currents during the pulse. The used HIPIMS power supply was a constant voltage supplies. Similarly, HIPIMS pulses with multiple steady state current phases can be generated using a modulated pulsed power (MPP) generator. A typical pulse consists of an ignition, low current and high current phase. The contribution of these phases to the deposition rate is presented. The ionization rate of single charge chromium ions has been found to increase linearly with increasing peak current density. An increase in deposition rate with lower magnetic field strength at the target surface can be attributed to a higher sputter yield due to a higher cathode voltage due to increasing system impedance in HIPIMS case, weaker trapping of deposition flux and to enhanced ion flux towards the substrate.