基于ARM的车辆视频检测技术研究

为解决交通拥堵问题, 设计并实现了一套具有实时、便捷、低成本、高精度、低误差的智能交通系统(ITS: Intelligent Transport System)。该系统由道路上架设的摄像头采集实时交通图像为主要研究对象, 在嵌入式Linux 系统下, 采用开源计算机视觉库(OpenCV)对车辆变道的行为信息进行统计计算, 并将完整程序移植到ARM11 微处理器上实现该算法。实验结果表明, 该系统的实时性好、统计结果准确; 系统工作稳定, 数据传输准确, 有效地避免了外界干扰, 具有较强的实用性。     

pH‐controlled reaction divergence of decarboxylation versus fragmentation in reactions of dihydroxyfumarate with glyoxylate and formaldehyde: parallels to biological pathways

The reactions of dihydroxyfumarate with glyoxylate and formaldehyde exhibit a unique pH‐controlled mechanistic divergence leading to different product suites by two distinct pathways. The divergent reactions proceed via a central intermediate (2,3‐dihydroxy‐oxalosuccinate, 3 , in the reaction with glyoxylate and 2‐hydroxy‐2‐hydroxymethyl‐3‐oxosuccinate, 14 , in the reaction with formaldehyde). At pH 7–8, products ( 7 , 8 , and 15 ) exclusively from a decarboxylation of the intermediate are observed, while at pH 13–14, products ( 9 , 10 , and 16 ) solely derived from a hydroxide‐promoted fragmentation of the intermediate are formed. The decarboxylative and fragmentation pathways are mutually exclusive and do not appear to coexist under the range of pH (7–14) conditions investigated. Herein, we employ a combination of quantitative ¹³C NMR measurements and density functional theory calculations to provide a rationale for this pH‐driven reaction divergence. These rationalizations also hold true for the reactions of dihydroxyfumarate produced in situ by the catalytic cyanide‐mediated dimerization of glyoxylate. In addition, the non‐enzymatic decarboxylation and fragmentation transformations of these central intermediates ( 3 and 14 ) appear to have intriguing parallels to the enzymatic reactions of oxalosuccinate and formation of glyceric acid derivatives in extant metabolism – the high and low pH mimicking the precise control exerted by the enzymes over reaction pathways. Copyright © 2016 John Wiley & Sons, Ltd.     

Optimization of detection device geometry for NIR spectroscopy using a three-layered model of stone fruit

The influences of detection device geometry and fiber optic parameters on near infrared spectroscopy measurements were assessed using stone fruit models based on Monte Carlo simulation. The stone fruit was modeled as concentric spherical layered tissues including the skin, the flesh and the core. The choices of the detection angle, the diameter of the detection fiber, the numerical aperture, and the height of the probe were discussed. Receiving diffuse reflectance signals at detection angles in the range of 35°–50° and normalizing the detection signals by the collection area and the solid acceptance angle prior to use are suggested. Fiber probes with diameters D = 0.06 cm or 0.1 cm, NA = 0.20 or 0.30, and height h ≤ 0.8 cm are preferred. The probe deflection angle should be limited to within ±5° to guarantee measurement accuracy.     

Surface resonant-states-enhanced acoustic wave tunneling in two-dimensional phononic crystals

We show that by placing a metal plate next to a two-dimensional phononic crystal, acoustic waves can tunnel through the combined structure at a specific frequency that lies inside the band gap of the phononic crystal. The enhanced transmission is attributed to the coupling of the input waves with the acoustically resonant states created between the metal plate and the phononic crystal. Experiments are in excellent agreement with the theoretical predictions.     

Tomonaga-Luttinger liquid features in ballistic single-walled carbon nanotubes: conductance and shot noise

We study the electrical transport properties of well-contacted ballistic single-walled carbon nanotubes in a three-terminal configuration at low temperatures. We observe signatures of strong electron-electron interactions: the conductance exhibits bias-voltage-dependent amplitudes of quantum interference oscillation, and both the current noise and Fano factor manifest bias-voltage-dependent power-law scalings. We analyze our data within the Tomonaga-Luttinger liquid model using the nonequilibrium Keldysh formalism and find qualitative and quantitative agreement between experiment and theory.     

Genome-wide analysis of genetic alterations in acute lymphoblastic leukaemia

Chromosomal aberrations are a hallmark of acute lymphoblastic leukaemia (ALL) but alone fail to induce leukaemia. To identify cooperating oncogenic lesions, we performed a genome-wide analysis of leukaemic cells from 242 paediatric ALL patients using high-resolution, single-nucleotide polymorphism arrays and genomic DNA sequencing. Our analyses revealed deletion, amplification, point mutation and structural rearrangement in genes encoding principal regulators of B lymphocyte development and differentiation in 40% of B-progenitor ALL cases. The PAX5 gene was the most frequent target of somatic mutation, being altered in 31.7% of cases. The identified PAX5 mutations resulted in reduced levels of PAX5 protein or the generation of hypomorphic alleles. Deletions were also detected in TCF3 (also known as E2A), EBF1, LEF1, IKZF1 (IKAROS) and IKZF3 (AIOLOS). These findings suggest that direct disruption of pathways controlling B-cell development and differentiation contributes to B-progenitor ALL pathogenesis. Moreover, these data demonstrate the power of high-resolution, genome-wide approaches to identify new molecular lesions in cancer.     

平面变栅距位相光栅位移传感器的测量精度极限

提出用透射式变栅距位相光栅作位移传感器,用标量衍射理论讨论了这种传感器的测量精度与光栅的起始栅距及栅距变化系数之间的关系,同时用时域有限元差分(FDTD)算法计算了变栅距位相光栅的衍射场,计算结果表明受衍射偏振特性的影响,这种位移传感器的测量精度在理论上存在极限.     

反气相色谱法研究共聚酯的表面性质及共混体系的相容性

采用反气相色谱法(IGC)测定了对苯二甲酸丁二醇酯-己内酯(PBT-PCL)多嵌段共聚物与溶剂的Flory-Huggins相互作用参数和色散成分的表面能γsd,研究了温度对γsd的影响.同时,通过探针分子测得聚氯乙烯(PVC)与PBT-PCL共混时的相互作用参数χ为-0.796,结果表明,该共混物是相容的.     

涉及微分多项式的全纯函数的正规性

通过研究全纯函数族的正规性,给出了一个一般性的正规定则,改进了李江涛和仪洪勋的结果.设F为区域D上的全纯函数族,k为正整数,并令a(z),b(z)≠0,c(z)≠0为D上解析函数.若对(∨)f∈F,f的零点重级至少为k,且f(z)=0(→)P(f)(k) H(k) H(f,f′,…,(f(k)))=a(z),P(f(k)) H(f,f′,…,f(k)))=b(z)(→)f(z)=c(z).则F在D上正规.