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121.
在分析红外图象和视图象差异的基础上,研究了一种适用于可视图像序列的运动小目标检测算法。受目标影响的象素点具有较弱的时间相关性,即相对普通象素点有较大的时间方差,根据此特征,用管道更新的方法产生新方差图象序列,再用管道更新的方法累积,增加信噪比,然后用基于统计均值的自适应门限方法分割出目标,最后将原图象的梯度倒数作为象素点强度的加权,有效地抑制灰度突变边界的传感器噪音,保存目标点。 相似文献
122.
123.
ZHANG Lin-bo LIU Xiao-hua JIANG Yuan GUO Ping SHA Li-jin LI Yu 《高等学校化学研究》2006,22(2):139-144
After establishing hemi-Parkinsonian rat models, the relationships between neuron death and the expression of several proteins, such as c-Fos, GFAP, GDNF, NF-κB and some cytokines were determined. Therapeutics experiments with notoginsenoside-Rg1 were carried out. The research results show that the expressions of GFAP, NF-Kκ and c-Fos will obviously increase in the lesion side of the striatum and the expression of GDNF will decrease, which implies that the signal transduction pathway may participate in the apoptosis in neurons. The levels of some cytokines such as TNF-α, IL-1β in the striatum of PD rat models increased compared to those of normal rats. The results of the therapeutics experiments show that notoginsenoside-Rg1 may repress the immune inflammation response and regulate the immune function through the neuro-immune molecular network. Therefore, notoginsenoside-Rg1 can be used as an effective drug for anti-oxidation and anti-inflammation, and can be used in the therapy of Parkinson's disease(PD). 相似文献
124.
氢化物发生-原子荧光法测定莲藕中的铅 总被引:4,自引:0,他引:4
采用原子荧光光谱法测定了莲藕中的痕量铅;优化了测定条件,考察了共存元素的干扰情况。在选定的最佳实验条件下,荧光强度与铅含量在0~30μg/L范围内呈线性关系,相关系数为0.9964,回收率为97.0%~103.6%,相对标准偏差≤3.1%。 相似文献
125.
126.
This study investigates a holographic recording effect of biphotonic polarization gratings (BPGs) written on dye-doped liquid crystal (DDLC) films. One linearly polarized green light (λG = 514.5 nm) and a polarization-modulated interference pattern formed by two mutually coherent orthogonal (±45° with respect to the polarization of the green light) polarized red lights simultaneously excite the DDLC films to generate a BPG. The formation of BPGs depends primarily on the dichroism of the dye molecules and a sequence of mechanisms: photoisomerization, anisotropic adsorption and inhibition of dye adsorption. The cis-isomer absorbance-modulated distribution associated with the red polarization-modulation pattern induces the dye adsorption-modulated pattern, in turn, yielding the permanent BPG which generates a modulated twisted nematic (TN) structure pattern in the sample. It is found that each BPG is verified to be electrically switchable and thermally erasable. The switching time is in the order of milliseconds. Additionally, the recording time to form a BPG decreases with increasing intensity of the green pump beam. 相似文献
127.
The single-longitudinal-mode Nd:GdVO4/RTiOPO4 (RTP) solid-state Green laser operation of a laser-diode (LD) end-pumped laser is realized by multi-cavities and a Brewster plate. The LD-pumped single-frequency green laser has been demonstrated by optimizing several parameters and a cavity length, with precise temperature controlling of Nd:GdV04, RTP and laser diode. When the incident pump power is 2 W at 808.4 nm, a single-frequency cw green laser at 532nm with output 210 m W is obtained, the optical-to-optical conversion efficiency is up to 10.5%. 相似文献
128.
本文用AES研究了P-InP/TiPdAu热处理前后的界面特性,结果表明:TiPd层对Au的内扩散和In的扩散有阻挡作用。以TiPdAu作InGaAsP/InP双异质结发光管的p面电极、镀Au作热沉,采用In焊料,研究了器件的可靠性问题,在室温大气气氛中;70℃存储,70~80℃带电老化,三种条件下长时间考核结果表明:器件的I-V特性正常,末见正向压降明显变化。还比较了Au-Zn材料作p面电极用TiPdAu作肖脱基势垒限制层制成的器件和用TiPdAu作电极材料制成的深Zn扩散型器件在老化过程中的特性变化,后二种结构的器件,在长期老化过程中,有源区中有大面积DSD生长和增殖。 相似文献
129.
引进了随机环境中多物种分枝随机游动的一般模型.在分枝过程非灭绝的情况下,讨论了系统的状态分类,得到了系统暂留及强常返的充要条件是存在k个定义在整数集上的函数分别满足某种性质.最后给出了系统强暂留的充分条件. 相似文献
130.
This work proposes and demonstrates the feasibility of gray image encryption using multiple polarization encoding, in which
the cascaded twisted nematic liquid crystal devices sandwiched between a crossed polarizer pair are used to implement exclusive
OR (XOR) logical encryption and decryption. The polarization encoding scheme provides a multichannel XOR logic operation to
secure bit-plane images derived from a gray image, according to the adiabatic following properties of twisted nematic liquid
crystal devices. Experimental data reveal that the multiple polarization encoding schemes for gray image encryption and decryption
are performed with acceptable image quality by selecting appropriate polarization orientation and modulation conditions. Both
analytic and experimental results are presented and discussed. 相似文献