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901.
为了克服化学检测痕量甲醛气体速度慢、有耗材、采样区域局限等缺点,实现快速准确地检测甲醛气体的浓度,设计了一种多特征波长窗的方法。根据甲醛及主要干扰气体的特征光谱选择相干度最小的多组特征波长,特征波长个数分别选用3,4和5个,同时配合相应的多组窄带滤光片。当光源依次通过这些窗口及气室后,由PCI-2TE-13型红外探测器采集,并经相关算法反演样气中的甲醛浓度。实验针对新装修的房屋、建材商场、超市及公园四种环境下采集的样气中的甲醛进行定量分析。实验结果与ARCSpectro-A-MIR型红外光谱仪的检测结果相比较,结果表明,采用多特征波长窗法在10μg.m-3以上的检测结果均与标准值相近,其平均误差均小于5%,满足实际应用的要求,并且具有实时检测、不中毒等优点。 相似文献
902.
Target detection is one of the key technology of precision chemical application.Previously the digital coding modulation technique was commonly used to emit and receive the optical signal in the target detection systems previously in China.It was difficult to adjust the output power,and the anti-interference ability was weak in these systems.In order to resolve these problems,the target detection method based on analog sine-wave modulation was studied.The spectral detecting system was set up in the aspects ... 相似文献
903.
904.
《Applied Mathematical Modelling》2014,38(9-10):2303-2310
Acceptance sampling has been widely used tool for determining whether the submitted lot should be accepted or rejected. However, it cannot avoid two kinds of risks, accepting undesired poor product lots and rejecting good product lots. Such risks are even more significant as the rapid advancement of the manufacturing technology and stringent customers demand is enforced. A yield index Spk has been developed to provide an exact measure on process yield or fraction nonconforming for normally distributed processes with two-sided specification limits. Therefore, the aim of this paper is to develop a variables sampling plan for evaluating the lot or process fraction nonconforming based on the yield index. The probability of lot acceptance is derived based on the sampling distribution and two-point condition on OC curve is used to determine the plan parameters. Tables of the plan parameters and step-by-step procedure are provided for the practitioner to make decision on lot sentencing especially for situations of products with very low fraction of nonconformities. 相似文献
905.
《Applied Mathematical Modelling》2014,38(19-20):4717-4732
In this paper, a communication scheme that could use a nonlinear dynamical system to create encrypted keys with an additional dimension is proposed, and the scheme could keep encrypted keys not to diverge. Since the divergence of encrypted keys (nonlinear signals) easily happens in non-linear systems coupled with other systems, the adaptive control approach, proposed in this paper, uses the universal state-space adaptive observer-based fault diagnosis/estimator and the high-performance tracker to eliminate the divergence of encrypted keys. At the same time, the receiver of communication retrieves informal messages by the universal state-space adaptive observer-based fault diagnosis/estimator and the high-performance tracker. Thus, this paper takes advantage of the merit of digital redesign methodology for a practical implementation of secure-communication, and the estimator solves the problem of secure communication. Thus developed a new approach could add more dimensions into nonlinear secure-communication systems without having the problem of divergence of encrypted keys. 相似文献
906.
《Applied and Computational Harmonic Analysis》2014,36(1):158-166
Gabor functions, Gaussian wave packets, are optimally localized in time and frequency, and thus in principle ideal as (frame) basis functions for a wavelet, windowed Fourier or wavelet-packet transform for the detection of events in noisy signals or for data compression. A major obstacle for their use is that a tailored efficient operator acting on the transform coefficients for altering the width of the wave packets does not exist. However, by virtue of a curious property of the Gabor functions it is possible to change the width of the wave packets using just one-dimensional convolutions with very short kernels. The cost of a wavelet-type transform based on the scheme presented below is similar to that of a low order wavelet transform for a compact kernel and significantly less than the algorithme à trous. The scheme can hence easily be employed for the processing of signals in real time. 相似文献
907.
908.
根据装备质量管理的特点对装备质量管理的风险因素进行了分析,依据指标体系的设计原则建立了装备质量管理风险评估的指标体系,并给出了基于网络层次分析法和粒子群优化算法的的装备质量管理风险评估指标权重值的确定方法.并给出了实例分析. 相似文献
909.
以建筑工程为研究对象,选取13项影响建筑工程质量因素的指标,运用解释结构模型(ISM)系统分析各因素之间的内在联系,并在此基础上建立4级多层次递阶结构模型,进一步精确描述各因素间的直接关系,从而直观地反映各因素间的层级关系及相互影响,并找到了影响建筑工程质量的根本原因,进而为改善我国建筑工程质量提供一定的参考依据. 相似文献
910.
《Analytical letters》2012,45(14):1185-1189
Abstract A specific and non-destructive test for basic esters of benzilic and α-glycolic acids in water is described. The compounds are collected on a glass fiber filter as water insoluble complexes with sodium tetraphenylboron. The filter is dried and sprayed with a 2-diphenylacetyl-l, 3-indandione-l-imine derivative. A positive test is the visual observation of fluorescence. 相似文献