Target detection for wideband radar has recently received extensive attention. The classical energy integrating(EI)detector will always accumulate excess clutter or noise energy,which leads to unacceptable performance...Target detection for wideband radar has recently received extensive attention. The classical energy integrating(EI)detector will always accumulate excess clutter or noise energy,which leads to unacceptable performance deterioration if the detection window is not selected properly. In this paper, an EI detector for the distributed targets in the Gaussian environment is proposed.First, at the stage of preparatory work, the target models are proposed, then, the problem formulation is introduced. Subsequently,in the aspect of optimizing the method of detection window search and the method of threshold setting, the detailed design stages of the proposed detector are provided. Furthermore, theoretical analyses show that the proposed detector is easy to hardware implementation, and it does not need the prior knowledge about the spatial distribution of the target scattering centers in practical radar detection application. Finally, the performance assessment conducted by Monte Carlo simulations verifies that the proposed detector outperforms the conventional detectors.展开更多
A novel method for analysis of three active components curcumin, demethoxycurcumin and bisdemethoxycurcumin in Curcuma longa L. was developed by HPLC coupled with electrochemical detection. Three curcuminoids were wel...A novel method for analysis of three active components curcumin, demethoxycurcumin and bisdemethoxycurcumin in Curcuma longa L. was developed by HPLC coupled with electrochemical detection. Three curcuminoids were well separated on a C18 column and detected with high sensitivity. A mobile phase containing acetonitrile and 10 mM Na2HPO4-H3PO4 （pH 5.0） （50：50, v/v） was used. Good linearity was obtained in the range of 0.208-41.6, 0.197-39.4, and 0.227-114μM for curcumin, demethoxycurcumin and bisdemethoxycurcumin respectively. The limit of detection reached up to 10 ？ 8 M, which was lower than that by UV detection. The relative standard deviations （RSDs） ranged from 1.06%to 1.88%for intra-day precision and from 4.30%to 5.79%for inter-day precision, respectively. The proposed method has been applied in real herb sample and recoveries ranging from 86.3%to 111%were obtained.展开更多
In this paper, a feasible scheme is reported for the detection and identification of trace alcohol congeners that have identical elemental composition using laser-induced breakdown spectroscopy （LIBS）. In the scheme...In this paper, a feasible scheme is reported for the detection and identification of trace alcohol congeners that have identical elemental composition using laser-induced breakdown spectroscopy （LIBS）. In the scheme, an intensive pulsed laser is used to break down trace alcohol samples and the optical emission spectra of the induced plasma are collected for the detection and identifq ication of alcohol molecules. In order to prepare trace alcohol samples, pure ethanol or methanol is bubbled by argon carrier gas and then mixed into matrix gases. The key issue for the scheme is to constitute indices from the LIBS data of the alcohol samples. Two indices are found to be suitable for alcohol detection and identification. One is the emission intensity ratio （denoted as H/C） of the hydrogen line （653.3 nm） to the carbon line （247.9 nm） for identification and the other is the ratio of the carbon line （as C/Ar） or the hydrogen line （as H/Ar） to the argon lines （866.7 nm） for quantitative detection. The calibration experiment result shows that the index H/C is specific for alcohol congeners while almost being independent of alcohol concentration. In detail, the H/C keeps a specific constant of 34 and 23 respectively for ethanol and methanol. In the meanwhile, the C/Ar and H/Ar indices respond almost linearly to the alcohol concentration below 1300 ppm, and are therefore competent for concentration measurement. With the indices, trace alcohol concentration measurement achieves a limit of 140 ppm using a laser pulse energy of 300 mJ.展开更多
Since unmanned ground vehicles often encounter concave and convex obstacles in wild ground, a filtering algorithm using line structured light to detect these long distance obstacles is proposed. For the line structure...Since unmanned ground vehicles often encounter concave and convex obstacles in wild ground, a filtering algorithm using line structured light to detect these long distance obstacles is proposed. For the line structured light image, a ranked-order based adaptively extremum median （RAEM） filter algorithm on salt and pepper noise is presented. In the algorithm, firstly effective points and noise points in a filtering window are differentiated; then the gray values of noise points are replaced by the medium of gray values of the effective pixels, with the efficient points＇ gray values unchanged; in the end this algorithm is proved to be efficient by experiments. Experimental resuits demonstrate that the image blur, resulting into proposed algorithm can remove noise points effectively and minimize the protecting the edge information as much as possible.展开更多
According to the proposed hypothesis, graphic characters trigger the subcortical visual route. The reaction discussed is very weak. Yet, its very existence has an unusual importance: characters and (occluded) venomous...According to the proposed hypothesis, graphic characters trigger the subcortical visual route. The reaction discussed is very weak. Yet, its very existence has an unusual importance: characters and (occluded) venomous snakeskin patterns reveal themselves as conflatable. Furthermore, following tractogra<span><span><span style="font-family:;" "="">- </span></span></span><span><span><span style="font-family:;" "="">phic research, a functional segregation of the subcortical pathway is to be <span>presupposed. Thus, there can’t be a later dissociation of two stimuli pre</span>viously associated. The outc</span></span></span><span><span><span style="font-family:;" "="">omes of lecture will gradually appear probabilistically <span>(much) more peaceful than encountering a venomous snake, though, and</span> thus a continuous lessening of the reaction is expectable. Here, on one hand, it is relevant that the subcortical visual pathway goes to the amygdala. The reactions we describe tap into goal-oriented processes, and they will do that un<span>fettered. On the other hand, in the case of characters, since the beginning,</span> fear has been converted into appetition to a great degree. This process should be fostered in the presence of light. In this way, luminosity might become a conditioned stimulus for attraction. In this case, a Pavlovian addiction for light <span>will foster, yet also—from the point of view of reward fee</span>ling—counterbalance the lessening of the stimulation elicited by characters. The addiction we refer to is one towards light accompanied by graphic signs. Yet, as opposed to the case of the luminous medium, the attention captured by the later ones taken for themselves is continuously reduced.</span></span></span>展开更多
基金supported by the National Natural Science Foundation of China(61571043)and the 111 Project of China(B14010)
文摘Target detection for wideband radar has recently received extensive attention. The classical energy integrating(EI)detector will always accumulate excess clutter or noise energy,which leads to unacceptable performance deterioration if the detection window is not selected properly. In this paper, an EI detector for the distributed targets in the Gaussian environment is proposed.First, at the stage of preparatory work, the target models are proposed, then, the problem formulation is introduced. Subsequently,in the aspect of optimizing the method of detection window search and the method of threshold setting, the detailed design stages of the proposed detector are provided. Furthermore, theoretical analyses show that the proposed detector is easy to hardware implementation, and it does not need the prior knowledge about the spatial distribution of the target scattering centers in practical radar detection application. Finally, the performance assessment conducted by Monte Carlo simulations verifies that the proposed detector outperforms the conventional detectors.
基金supported by the National Scientific Foundation of China (Grant nos.21375101,90817103,and 30973672)Doctroral Fund of Ministry of Education of China (No.20110141110024)Innovation Seed Fund and Translational Medical Research Fund of Wuhan University School of Medicine
文摘A novel method for analysis of three active components curcumin, demethoxycurcumin and bisdemethoxycurcumin in Curcuma longa L. was developed by HPLC coupled with electrochemical detection. Three curcuminoids were well separated on a C18 column and detected with high sensitivity. A mobile phase containing acetonitrile and 10 mM Na2HPO4-H3PO4 （pH 5.0） （50：50, v/v） was used. Good linearity was obtained in the range of 0.208-41.6, 0.197-39.4, and 0.227-114μM for curcumin, demethoxycurcumin and bisdemethoxycurcumin respectively. The limit of detection reached up to 10 ？ 8 M, which was lower than that by UV detection. The relative standard deviations （RSDs） ranged from 1.06%to 1.88%for intra-day precision and from 4.30%to 5.79%for inter-day precision, respectively. The proposed method has been applied in real herb sample and recoveries ranging from 86.3%to 111%were obtained.
基金supported by National Natural Science Foundation of China(Nos.11375041,10675028)the Fundamental Research Funds for the Central Universities(No.DUT11ZD(G)06)the Fund of the Key Laboratory of Chemical Laser,CAS(No.20131008)
文摘In this paper, a feasible scheme is reported for the detection and identification of trace alcohol congeners that have identical elemental composition using laser-induced breakdown spectroscopy （LIBS）. In the scheme, an intensive pulsed laser is used to break down trace alcohol samples and the optical emission spectra of the induced plasma are collected for the detection and identifq ication of alcohol molecules. In order to prepare trace alcohol samples, pure ethanol or methanol is bubbled by argon carrier gas and then mixed into matrix gases. The key issue for the scheme is to constitute indices from the LIBS data of the alcohol samples. Two indices are found to be suitable for alcohol detection and identification. One is the emission intensity ratio （denoted as H/C） of the hydrogen line （653.3 nm） to the carbon line （247.9 nm） for identification and the other is the ratio of the carbon line （as C/Ar） or the hydrogen line （as H/Ar） to the argon lines （866.7 nm） for quantitative detection. The calibration experiment result shows that the index H/C is specific for alcohol congeners while almost being independent of alcohol concentration. In detail, the H/C keeps a specific constant of 34 and 23 respectively for ethanol and methanol. In the meanwhile, the C/Ar and H/Ar indices respond almost linearly to the alcohol concentration below 1300 ppm, and are therefore competent for concentration measurement. With the indices, trace alcohol concentration measurement achieves a limit of 140 ppm using a laser pulse energy of 300 mJ.
基金Supported by the National Natural Science Foundation of China(61273346)the National Defense Key Fundamental Research Program of China(A20130010)the Program for the Fundamental Research of Beijing Institute of Technology(2016CX02010)
文摘Since unmanned ground vehicles often encounter concave and convex obstacles in wild ground, a filtering algorithm using line structured light to detect these long distance obstacles is proposed. For the line structured light image, a ranked-order based adaptively extremum median （RAEM） filter algorithm on salt and pepper noise is presented. In the algorithm, firstly effective points and noise points in a filtering window are differentiated; then the gray values of noise points are replaced by the medium of gray values of the effective pixels, with the efficient points＇ gray values unchanged; in the end this algorithm is proved to be efficient by experiments. Experimental resuits demonstrate that the image blur, resulting into proposed algorithm can remove noise points effectively and minimize the protecting the edge information as much as possible.
文摘According to the proposed hypothesis, graphic characters trigger the subcortical visual route. The reaction discussed is very weak. Yet, its very existence has an unusual importance: characters and (occluded) venomous snakeskin patterns reveal themselves as conflatable. Furthermore, following tractogra<span><span><span style="font-family:;" "="">- </span></span></span><span><span><span style="font-family:;" "="">phic research, a functional segregation of the subcortical pathway is to be <span>presupposed. Thus, there can’t be a later dissociation of two stimuli pre</span>viously associated. The outc</span></span></span><span><span><span style="font-family:;" "="">omes of lecture will gradually appear probabilistically <span>(much) more peaceful than encountering a venomous snake, though, and</span> thus a continuous lessening of the reaction is expectable. Here, on one hand, it is relevant that the subcortical visual pathway goes to the amygdala. The reactions we describe tap into goal-oriented processes, and they will do that un<span>fettered. On the other hand, in the case of characters, since the beginning,</span> fear has been converted into appetition to a great degree. This process should be fostered in the presence of light. In this way, luminosity might become a conditioned stimulus for attraction. In this case, a Pavlovian addiction for light <span>will foster, yet also—from the point of view of reward fee</span>ling—counterbalance the lessening of the stimulation elicited by characters. The addiction we refer to is one towards light accompanied by graphic signs. Yet, as opposed to the case of the luminous medium, the attention captured by the later ones taken for themselves is continuously reduced.</span></span></span>
