Optimization of Superlattice Thermoelectric Materials and Microcoolers

The performance of thermoelectric (TE) coolers is determined by the figure of merit of the TE materials ZT. In order to obtain the optimal performance of a superlattice microcooler, both the superlattice structure and the device were optimized in the design and the fabrication process. The thermal conductivities of InGaAs/InGaAsP superlattices with different periodic lengths were measured with the 3omega method. The result indicates that the superlattice at a certain periodic length has minimal thermal conductivity, which, in general, corresponds to an enhanced ZT. A 1D model was utilized to investigate the significant parameters in microcoolers. Based on the modeling results, a set of superlattice microcoolers were fabricated. The maximum cooling temperature that was reached is 0.76degC for the optimized cooler at room temperature.     

82B方坯连铸末端电磁搅拌位置优化研究

采用射钉方法测定天津钢铁有限公司1^#铸机82B150mm方坯在工作拉速条件下不同位置上的的凝固坯壳厚度，得到了铸坯的综合凝固系数和液相穴长度，计算了铸坯末端电磁搅拌的最佳安装位置，为优化连铸工艺提供了重要依据。     

自蔓延高温合成技术法合成La0.7Sr0.3MnO3过程的热力学分析

通过热力学计算研究自蔓延高温合成技术合成La0.7Sr0.3MnO3反应机制。结果表明：对于Mn，La2O3，SrCO3，NaClO4组成的自蔓延高温合成La0.7Sr0.3Mn0.3反应体系，理论上Mn粉优先与La2O3反应生成LaMnO3，低温下Mn粉优先与O2反应生成少量MnOx，大部分剩余的Mn粉高温（〉1417K）下优先与O2反应生成SrMnO3；同时，少量低温（〈1417K）时形成的MnOx与SrCO3反应生成SrMnO3。高温下，SrMnO3与LaMnO3反应生成La0.7Sr0.3MnO3，这是SHS法合成La0.7Sr0.3MnO3的主要途径。另外，当温度大于1235K时，少量La2O3与SrCO3反应生成La2SrOx，La2SrOx再与LaMnO3反应生成La0.7Sr0.3Mn0.3。     

燃气炉内燃烧工况对NOx生成特性的影响

降低NOx的排放量是燃气炉洁净燃烧过程的重要研究内容之一。建立单烧嘴平焰燃烧炉实验模型，通过准确测量炉内温度场和烟气中NOx，研究了空气预热和空气不预热两种工况对炉内火焰特性、温度场和烟气中NOx生成特性的影响规律。研究结果表明：空气预热工况下燃烧区和炉膛顶部温度场更加均匀，进而有效降低烟气中NOx的浓度。     

Influence of Ce0.35Zr0.55Y0.10 Solid Solution on Performance of Pt-Rh Three-Way Catalysts

Ce0.35Zr0.55Y0. 10 solid solution was prepared by co-precipitation technique and characterized by specific surface area measurements （BET） and X-ray diffraction （XRD）. Ce0.35Zr0.55Y0.10 was used to prepare low Pt-Rh threeway catalyst （TWC）, and its influence on the performance of TWC was investigated. The results revealed that Ce0.35 Zr0.55Y0.10 had a cubic structure similar to Ce0.50Zr0.50O2 and its specific surface area can maintain higher than Ce0.50 Zr0.50O2 after 1000 ℃ calcination for 5 h. Being hydrothermal aged at 1000 ℃ for 5 h, the catalyst containing Ce0.35 Zr0.55Y0.10 still exhibited higher conversion of C3H8, CO and NO and lower light-off temperature in comparison with Ce0.50Zr0.50O2 TWC.     

1422粗轧带钢板廓形状变化仿真研究

采用有限元的方法建立带钢立轧/平轧的三维模型,对热轧带钢粗轧过程的板廓的变化规律进行了仿真研究,重点分析了各道次轧制后带钢板廓形状和边角的位置变化,以及材质,立辊辊形,立轧压下量等因素对边角位置的影响.研究结论为现场解决热轧带钢表面的边部黑线缺陷问题提供了技术思路,为工厂最终解决此一表面缺陷提供了帮助.     

智能涡街流量变送器

介绍采用MSP430微功耗微处理构成的智能补偿电路及软件。该电路接受涡街流量变送器输出的脉冲fi，根据频率fi一线性度E曲线，软件采用多点线性内查补偿运算出与流量成正比的频率fic，为确保频率fic的转换精度，微处理器的定时器接受双时钟源，输出占空比为50％PWM方波，从而提高变送器的线性度及准确度。     

你的办公设备上保险了么

随着数码办公热潮的袭来,很多企业已逐渐实现了彩色办公,使用数码办公设备的诸多优势也被企业所认同,而如何让数码设备不问断地为企业提供更好的服务,保证输出品质?企业又如何不用为办公设备的耗材和维修而担忧?目前比较流行为数码办公设备上道"保险",企业就可零风险地使用设备了.     

Development and analysis of a 12-year daily 1-km forest fire dataset across North America from NOAA/AVHRR data

Fires in boreal and temperate forests play a significant role in the global carbon cycle. While forest fires in North America (NA) have been surveyed extensively by U.S. and Canadian forest services, most fire records are limited to seasonal statistics without information on temporal evolution and spatial expansion. Such dynamic information is crucial for modeling fire emissions. Using the daily Advanced Very High Resolution Radiometer (AVHRR) data archived from 1989 to 2000, an extensive and consistent fire product was developed across the entire NA forest regions on a daily basis at 1-km resolution. The product was generated following data calibration, geo-referencing, and the application of an active fire detection algorithm and a burned area mapping algorithm. The spatial-temporal variation of forest fire in NA is analyzed in terms of (1) annual and monthly patterns of fire occurrences in different eco-domains, (2) the influence of topographic factors (elevation zones, aspect classes, and slope classes), and (3) major forest types and eco-regions in NA. It was found that 1) among the 12 years analyzed, 1989 and 1995 were the most severe fire years in NA; 2) the majority of burning occurred during June-July and in low elevation zones (< 500 m) with gentle slopes (< 10°), except in the dry eco-domain where more fires occurred in higher elevation zones (> 2000 m); 3) most fires occurred in the polar eco-domain, sub-arctic eco-division, and in the taiga ( boreal forests), forest-tundras and open woodlands eco-provinces in the boreal forests of Canada. The tendency for multiple burns to occur increases with elevation and slope until about 2500 m elevation and 24° slope, and decreases therefore. In comparison with ground observations, the omission and commission errors are on the order of 20%.     

Multi-object trajectory tracking

The majority of existing tracking algorithms are based on the maximum a posteriori solution of a probabilistic framework using a Hidden Markov Model, where the distribution of the object state at the current time instance is estimated based on current and previous observations. However, this approach is prone to errors caused by distractions such as occlusions, background clutters and multi-object confusions. In this paper, we propose a multiple object tracking algorithm that seeks the optimal state sequence that maximizes the joint multi-object state-observation probability. We call this algorithm trajectory tracking since it estimates the state sequence or “trajectory” instead of the current state. The algorithm is capable of tracking unknown time-varying number of multiple objects. We also introduce a novel observation model which is composed of the original image, the foreground mask given by background subtraction and the object detection map generated by an object detector. The image provides the object appearance information. The foreground mask enables the likelihood computation to consider the multi-object configuration in its entirety. The detection map consists of pixel-wise object detection scores, which drives the tracking algorithm to perform joint inference on both the number of objects and their configurations efficiently. The proposed algorithm has been implemented and tested extensively in a complete CCTV video surveillance system to monitor entries and detect tailgating and piggy-backing violations at access points for over six months. The system achieved 98.3% precision in event classification. The violation detection rate is 90.4% and the detection precision is 85.2%. The results clearly demonstrate the advantages of the proposed detection based trajectory tracking framework.