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101.
脉搏血氧饱和度检测仪可以无损、实时地检测动脉血液中的含氧百分比,从而快速对人体的呼吸状况以及心肺功能作出判断,但其检测精度极易受到测试部位运动的影响.人体测试部位的运动大致可以分为突发性运动干扰以及周期性的运动干扰.突发性干扰表现在局部脉搏波的波形突变上,而周期性的干扰体现在多个局部脉搏波的波形的周期性变化上.文章有针对性地提出了一种将微分阈值分段与迭带中值滤波相结合的方法来剔除突发扰动的方法,并且在上诉方法上再加上一级多点移动平滑以消除周期性运动干扰.实验证明该方法在消除多种运动伪差上有着较好的效果,且该方法计算简单,易于实现,有着一定的实际应用价值. 相似文献
102.
Jinxia Gua b Zhipeng Baib Weifang Lib Liping Wua Aixia Liuc Haiyan Dongd Yiyang Xiec a Tianjin Institute of Urban Construction Tianjin China b State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention Control College of Environmental Science Engineering Nankai University Tianjin China c Tianjin Institute of Meteorological Instruments Tianjin China d Tianjin Environmental Monitoring Central Station Tianjin China 《中国颗粒学报》2011,(3)
PM2.5 samples for 24 h were collected during winter in Tianjin,China. The ambient mass concentration and chemical composition of the PM2.5 were determined. Ionic species were analyzed by ion chromatog-raphy,while carbonaceous species were determined with the IMPROVE thermal optical reectance(TOR) method,and inorganic elements were measured by inductively coupled plasma-atomic emission spec-trometer. The daily PM2.5 mass concentrations ranged from 48.2 to 319.2 g/m3 with an arithmetic average of 144.6 g/m3. ... 相似文献
103.
<正>SnO_2 nanorods were deposited on the Si substrates in an aqueous solution containing both SnCl_4 and CO(NH_2)_2.It is found that different self-assembled patterns of SnO_2 nanorods can be obtained by changing the deposition conditions such as the molar ratio of CO(NH_2)_2 to SnCl_4 and the pretreatment of the substrate.Scattered SnO_2 nanorods,for example,can be changed into flower-like patterns when the molar ratio of CO(NH_2)_2 to SnCl_4 is raised,and well-aligned nanorod arrays can be formed when the pretreatment of the substrate is changed.In addition,some interesting patterns,e.g.tree-like patterns,can also be observed. 相似文献
104.
WANG QianXin & XU TianHe School of Information Physics Geomatics Engineering Central South University Changsha China Geodesy Department Xi'an Research Institute of Surveying Mapping Xi'an 《中国科学:物理学 力学 天文学(英文版)》2011,(6)
The truncation error and propagation error are analyzed for velocity determination through differential GPS carrier phase observations,and an approach for the choice of the best number of points for the central difference method is developed.In order to overcome the disadvantages of existing GPS velocity determination methods,a new velocity determination algorithm is presented,based on combining carrier phase and Doppler observations.The basic idea is that two types of observation are combined by adding the... 相似文献
105.
ZHANG QingChao PANG ShuJie LI Yi & ZHANG Tao Key Laboratory of Aerospace Materials Performance School of Materials Science Engineering Beijing University of Aeronautics Astronautics Beijing China 《中国科学:物理学 力学 天文学(英文版)》2011,(9)
Bulk metallic glasses (BMGs) with large supercooled liquid region are promising materials for superplastic forming. In this paper, we demonstrate a microstructure-based strategy to pinpoint the composition with the largest supercooled liquid region in La 86 x Al 14 Cu x (x=16 at%-20 at%) metallic glass system. By monitoring the changes in crystallization behavior of the glassy alloys with composition to search for the alloys exhibiting eutectic crystallization, the glassy alloys with the largest supercooled... 相似文献
106.
Novel correction method for X-ray beam energy fluctuation of high energy DR system with a linear detector 总被引:1,自引:0,他引:1
A high energy digital radiography (DR) testing system has generated diverse scientific and technological interest in the field of industrial non-destructive testing. However, due to the limitations of manufacturing technology for accelerators, an energy fluctuation of the X-ray beam exists and leads to bright and dark streak artifacts in the DR image. Here we report the utilization of a new software-based method to correct the fluctuation artifacts. The correction method is performed using a high pass filtering operation to extract the high frequency information that reflects the X-ray beam energy fluctuation, and then subtracting it from the original image. Our experimental results show that this method is able to rule out the artifacts effectively and is readily implemented on a practical scanning system. 相似文献
107.
ZHANG ZhaoXiang ZHANG XiaoWei & LI Feng Key Laboratory of Eco-Chemical Engineering Ministry of Education College of Chemistry Molecular Engineering Qingdao University of Science Technology Qingdao China School of Science Qingdao Technological University Qingdao China 《中国科学:化学》2010,(5)
A novel method has been developed by integration of multi-concentration and two-dimensional(2D) capillary electrophoresis(CE) for simultaneous enhancement of detection sensitivity and separation power in complex samples.Capillary zone electrophoresis(CZE) was used as the first dimension separation according to mobilities,from which the effluent fractions were further analyzed by micellar electrokinetic capillary chromatography(MEKC) acting as the second dimension.Cation-selective exhaustive injection(CSEI) ... 相似文献
108.
HAN Jun DENG Chao FANG Ru LI YiZhi WANG LeYong& PAN Yi Key Laboratory of Mesoscopic Chemistry Ministry of Education School of Chemistry Chemical Engineering Nanjing University Nanjing China State Key Laboratory of Coordination Chemistry 《中国科学:化学》2010,(4)
Three tripod molecules, tris(2-methoxy-5-nitrobenzyl)phosphine oxide (1), tris(2-butoxy-3-methyl-5-nitrobenzyl)phosphine oxide (2), and tris(3-nitrobenzyl)amine (TNBA), were synthesized and crystallized. The structures of 1, 2, and their comparison (TNBA) were determined by X-ray crystallography. It is noteworthy that compound 1 interacted with adjacent molecules via π-π stacking and C-H···π interactions to yield an open supramolecular network with the porosity P in 8.9%, whereas compound 2 gathered closely... 相似文献
109.
SHEN ChangSheng SUN YongZhi SUN DeKun & YANG HongSheng State Key Laboratory of Millimeter Waves School of Electronic Science Engineering Southeast University Nanjing China School of Chemistry Chemical Engineering Nanjing University Nanjing 《中国科学:化学》2010,(1)
By optimizing the microwave chemistry reactor made of the rectangular waveguide resonator,the methane conversion(the maximum 93.7%),the C2 hydrocarbon yield(the maximum 91.0%) and the acetylene yield(the maximum 88.6%) were all greatly increased under the microwave plasma.Furthermore,for the optimal reactor,the change of the methane conversion and the C2 hydrocarbon yield is little within the range of the pressures in the experiments.The C2 hydrocarbon is mainly made up of acetylene,and the selectivity for ... 相似文献
110.
Xin ZHOU Shrong Shi LIN Jin Fang YUAN* Zhe Ming WANG Hong Zhong WANG College of Chemical Molecular Engineering Peking University Beijing Department of Biological Sciences & Biotechnology Tsinghua Univ 《中国化学快报》2001,(10)
A lot of attentions have been paid to the synthesis of benzothiazepines and derivatives1,2 due to their significant physiological activities. It has been reported that b-lactam, a major part of the antibiotic skeleton, can be introduced to a molecule by reaction of an imine moiety with ketene3,4. We introduced a b-lactam skeleton to benzothiazepine and hoped the new compounds may possess certain biological activities. SHNH3ClCHCHCOC2H5OHSNClCla: ortho-Clb: para-Cl+PyridineScheme … 相似文献