基于聚偏二氟乙烯步态智能检测的乘客计数系统

针对现有的以低成本、耐损耗的聚偏二氟乙烯(PVDF)为压电材料的客流计数传感器存在的误计数、漏计数而导致精度不够的问题,提出了一种基于PVDF步态智能检测技术的乘客计数系统。采用ANSYS软件对乘客上下车步态作应力分析,观察PVDF压电信号的分布规律,设计多输入信号调理电路获取多通道足底信号,结合信号处理算法,设计了传感器机械结构和基于实验室虚拟仪器集成环境(LabVIEW)的公交车人数统计系统。实验结果表明,该系统平均计数误差为5.3%,与已有的PVDF客流计数传感器相比,提高了精度;与视频图像计数和人体红外检测技术相比,大大降低了成本,具有很高的实用性,可以广泛应用于我国公共交通客运车。     

刀具涂层的分类与应用

提出了刀具涂层的分类方法,分析了涂层刀具的选择依据。     

动态联盟中伙伴选择的Top-k问题的优化算法

为研究大规模复杂供应链环境下合作伙伴选择的效率问题,从加速选择过程的角度入手,将Top-k优化思想引入虚拟企业合作伙伴选择过程,并对基本选择指标进行了分类,提出了基于特殊指标的优化选择过程。实验表明,通过该方法能够显著提高选择过程的效率。进一步改进了选择过程算法,提出了改进优化程序算法。仿真实验结果表明,该算法能有效地克服选择过程算法的误判率,提高合作伙伴选择的精度。     

Development of an energy-binned photon-counting detector for X-ray and gamma-ray imaging

The aim of this study is to develop an energy-binned photon-counting (EBPC) detector that enables us to provide energy information of x-rays with a reasonable count statistics. We used Al-pixel/CdTe/Pt semiconductor detectors, which had an active area of 8 mm×144 mm and consisted of 18 modules aligned linearly. The size of a CdTe detector module was 8 mm×8 mm and the thickness of the CdTe crystal was 1 mm. Each module consisted of 40×40 pixels and the pixel size was 200 μm×200 μm. We applied the bias voltage of −500 V to the Pt common electrode. The detector counted the number of x-ray photons with four different energy windows, and output four energy-binned images with pixel depths of 12, 12, 11 and 10 bits at a frame rate of 1200 Hz (300 Hz×4 energy bins). The basic performance of the detector was evaluated in several experiments. The results showed that the detector realized the photon counting rate of 0.4×10⁶ counts/sec/pixel (10⁷ counts/sec/mm²), energy resolution 4.4% FWHM at 122 keV. The integral uniformity of the detector was about 1% and the differential uniformity was about 1%. In addition, the image quality was examined with a resolution chart and step-wedge phantoms made of aluminum and polymethyl methacrylate. And we compared the quality of an acquired image with that acquired with an energy integration detector. The results of these experiments showed that the developed detector had desirable intrinsic characteristics for x-ray photon counting imaging.     

消除规范关系连接冗余的二次排序算法研究

使用MapReduce框架对规范的一对多关系实体进行连接操作时,一方实体的各个属性会在连接的结果中产生大量冗余. 通过对二次排序算法进行优化,重新定义Map阶段的分区过程、Shuffle阶段的排序及分组过程,使得Map阶段的输出为包含一方实体属性值和多方实体排序值的组合键及包含多方实体属性值的集合. Reduce阶段将组合键进行分解,提取一方实体的主码作为HBase表的行健,并将组合键中一方实体的各个属性值及多方实体属性值集合分别写入HBase表中对应的列,从而既实现了连接的语义,又消除了冗余. 实验证明,优化后的算法可以消除一方实体属性值在连接结果中的冗余,提高了对连接结果的查询效率.     

基于词语相关度的微博新情感词自动识别

针对微博中新情感词的识别问题,提出了一种基于词语相关度的微博新情感词自动识别方法。首先,对于分词软件把一个新词错分成几个词的问题,利用组合思想将相邻词进行合并作为新词的候选词;其次,为了充分利用词语上下文的语义信息,采用神经网络训练语料获得候选新词的空间表示向量;最后,利用已有的情感词典作为指导,融合基于词表集合的关联度排序和最大关联度排序算法,在候选词上筛选,获得最终的情感新词。在COAE2014(第六届中文倾向性分析评测)任务3语料上,提出的融合算法与点互信息(PMI)、增强互信息(EMI)、多词表达距离(MED)、新词语概率(NWP)以及基于词向量的新词识别方法相比,准确率至少提高了22%,说明该方法自动识别微博新情感词效果优于其他五种方法。     

基于WinCC6．0及S7-200PLC的材料分拣监控系统设计

本文采用西门子s7-200系列PLC和winCC监控软件相结合的控制模式,实现了材料、分拣的全自动监视与控制。S7-200PLC和以WinCC为OPC客户端的监控软件之间的通讯采用s7—200PCACCESS作为OPC服务器实现。经过对材料分拣装置的实时监控,证明系统稳定性和准确度较好,能满足监控系统的需要。     

Performance evaluation of three optical particle counters with an efficient “multimodal” calibration method

The sizing accuracies of two widely used yet hitherto unevaluated optical particle counters (OPCs—Grimm Model 1.109 and Palas Model WELAS 2100) as well as one high-resolution, non-commercial OPC were evaluated. The measured data were compared to scattering intensity calculations based on Mie theory. Additionally, the counting efficiency for all three counters was measured, as was the influence of coincidence effects for the OPC with the lowest (manufacturer specified) upper concentration limit.Beside the traditional polystyrene latex calibration, a little-known, very fast and precise “multimodal” calibration method was used, which is based on the simultaneous generation of up to eight sharp multiple-charge modes from polydisperse di-ethyl-hexyl-sebacate (DEHS) particles by electrical mobility classification.     

High Speed Photon Number Resolving Detector with Titanium Transition Edge Sensor

We have developed new photon number resolving detectors with titanium transition edge sensors (Ti-TESs) for a high counting rate operation in quantum information. The titanium superconducting films were fabricated by ultra-high vacuum electron beam evaporation, and showed a sharp superconducting transition at 359 mK. The device was coupled to a single mode optical fiber, and cooled down to 100 mK. Some of optical responses of the devices were measured by illuminating heavily attenuated laser pulses at wavelengths of 405 and 1550 nm. As a result, the device showed a fast decay time constant of 300 ns, which enables the operation at the counting rate of 400 kcps. The energy resolution was 0.76 eV at 405 nm and 0.68 eV at 1.5 μm, that make it possible to clearly resolve the number of photons of incident laser pulses. These features of the high counting rate operation and the reasonable energy resolution are very promising for quantum information field.      

A phenolic antioxidant from the Pacific oyster (Crassostrea gigas) inhibits oxidation of cultured human hepatocytes mediated by diphenyl-1-pyrenylphosphine

3,5-Dihydroxy-4-methoxybenzyl alcohol (DHMBA), an antioxidant isolated from the Pacific oyster (Crassostrea gigas), was studied in a cell-based fluorometric antioxidant assay using human hepatocyte-derived cells (C3A) and diphenyl-1-pyrenylphosphine (DPPP) as a fluorescent probe. In comparison with two hydrophilic antioxidants, DHMBA showed the stronger inhibition of DPPP-mediated fluorescence than chlorogenic acid and l-ascorbic acid: at a concentration of 320 μM of DPPP, the inhibition was 26.4 ± 2.6%, 11.1 ± 1.2%, and 0 ± 2.0% for DHMBA, chlorogenic acid, and l-ascorbic acid, respectively (mean ± SD, n = 4). Their relative oxygen radical absorbance capacities (ORAC) were dissociated with their cell-based antioxidant activities: 1.47 ± 0.40, 4.57 ± 0.30, and 0.53 ± 0.13 μmol TE/μmol for DHMBA, chlorogenic acid, and l-ascorbic acid, respectively (mean ± SD, n = 4). The amphiphilicity of DHMBA was better than chlorogenic acid and l-ascorbic acid might underlie this dissociation. Since the C3A cells are human hepatoma-derived cells, DHMBA might be useful in the prevention and treatment of liver diseases by involving an oxidation process.