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Automatic determination of optimal spectral peaks for classification of Chinese tea varieties using laser-induced breakdown spectroscopy

Automatic determination of optimal spectral peaks for classification of Chinese tea varieties using laser-induced breakdown spectroscopy

Abstract: The accurate identification of tea varieties is of great significance to ensure the interests of tea producers and consumers. As a non-destructive or micro damage detection method, laser-induced breakdown spectroscopy (LIBS) has been widely used in the quality detection or classification of agricultural products and food. The objective of this research was to automatically select optimal spectral peaks from the full LIBS spectra, and develop effective classification model for identifying tea varieties. The LIBS spectra covering the region 200-500 nm were measured for 600 Chinese tea leaves including six varieties (i.e. Longjing green tea, Jinhao black tea, Tie Guanyin, Huang Jinya, White peony tea, and Anhua dark tea). A total of 50 optimal spectral peaks were automatically selected from full LIBS spectra (6102) by using the uninformative variable elimination (UVE) and partial least squares projection analysis, and the selected spectral peaks mainly represent the elemental difference in C, Fe, Mg, Mn, Al and Ca. Partial Least Squares Discriminant Analysis (PLS-DA) was used for developing classification model using selected optimal spectral peaks, and yielded the 99.77% classification accuracy for 300 test samples was reached. The results indicate that the proposed method can be used to identify leaf varieties in various tea products.
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Angle-dependent modulated spectral peaks of proton beams generated in ultrashort intense laser-solid interactions

Angle-dependent modulated spectral peaks of proton beams generated in ultrashort intense laser-solid interactions

longitudinal and transverse momentum, respectively. The blue lines correspond to the E>0.8 MeV protons, and the black lines to the 0.2~0.8 MeV protons. The E<0.8 MeV protons have large transverse momentum. However, the transverse momentum of the E>0.8 MeV protons is much lower than the longitudinal momentum. This indicates that the low energy protons are much scattered and the high energy protons are directional. The experimental angle-dependent spectral peaks are believed to be caused by the deflection of the protons due to the self-generated magnetic field. Under the influence of the field, most of the E<0.8 MeV protons are deflected out of the collection angle of 2.5mrad, while the E>0.8 MeV protons are not. Therefore, the counts of the E>0.8 MeV protons are outstanding in the spectrum.
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Role of Spectral Peaks in Autocoorelation Domain for Robust Speech Recognition

Role of Spectral Peaks in Autocoorelation Domain for Robust Speech Recognition

frames of 256 samples each, and a pre-emphasis filter is applied on each frame. A Hamming window is used, and then, the autocorrelation sequence of the frame signal is obtained using a biased estimator, as given by eq. ( 4 ) . A tempo- ral filtering is then applied to the autocorrelation sequence to obtain the relative autocorrelation sequence ( RAS ) in order to suppress the ad- ditive noise. When speech is corrupted by an additive noise, the noise component is additive to the speech not only in the autocorrelation do- main, but also in the power spectrum domain. In the next step, differentiated relative autocorrela- tion sequence spectrum ( DRASS ) is calculated by taking the differentiation of the power spec- trum of the relative autocorrelation coefficients ( RAS ) . Differentiation of the autocorrelation spectrum of the noisy speech signal preserves the spectral peaks, however, each peak has now positive and negative parts. In addition, the flat part of the power spectrum is approximately zero. Figure 2 depicts a sample speech signal, its short-time autocorrelation spectrum and the differentiated short-time autocorrelation spec- trum. This sample signal corresponds to one frame of sample speech. In order to simplify the spectrum representation, only the signifi- cant lower-frequency parts of the spectrum have been shown and the non-significant parts have been omitted. As shown in Figure 2 and as men- tioned above, the flat parts of the filtered auto- correlation spectrum have been transformed to zero by differentiation and each peak has two
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Spectral peaks in electric field at resonance frequencies for seismically excited motion of ions in the Earth’s magnetic field

Spectral peaks in electric field at resonance frequencies for seismically excited motion of ions in the Earth’s magnetic field

Clear electric field variations have been observed during the passage of seismic wave. The most notable feature is circular polarization of electric field and it has been interpreted as reflecting circular motion of ions in groundwater under the Earth’s magnetic field. We have called such a mechanism ‘seismic dynamo effect’ but more convincing evidence is required to support this mechanism. Here we show strong evidence in terms of transfer function relating the electric field to the ground velocity due to seismic wave. We estimate transfer functions for electric field and ground velocity records for five aftershocks after the occurrence of M 6.9 earthquake. Then some peaks in the transfer function are found at specific frequencies where the resonance of ion motion in groundwater with the Earth’s magnetic field is expected. This result clearly supports the mechanism, which provides a method for in-situ estimation of ion contents in groundwater.
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Scaling of ion spectral peaks in the hybrid RPA-TNSA region

Scaling of ion spectral peaks in the hybrid RPA-TNSA region

experiment, the relatively narrow band spectral feature appears (along the laser axis) simultaneously for proton and carbon species. Therefore, a spatially and spectrally resolved profile of the proton beam was captured in another shot employing a RCF stack as shown in the fig. 4 (a). The spatially resolved proton beam profiles produce information on the divergence in addition to the dose distribution. As the stopping range of carbon is significantly shorter than for protons at the same energy/nucleon (for example, stopping range of 5 MeV/nucleon proton and carbon in mylar are 300 μm and 100 μm respectively), on the basis of the TP spectra observed, the deposited dose in the RCFs in the stack (wrapped with 30 μm Aluminum foil to avoid the laser debris) can be assumed to be primarily due to the protons. The proton spectrum from the RCFs was reproduced by deconvolution method. Fig. 4 (b) shows the comparison between the proton spectra obtained from TP1 and the spectra at different locations in the RCF marked by the letters A, B and C. The position of the Thompson spectrometer is denoted by TP. The narrow band feature in the proton spectrum observed in the TP1 was reproduced (dashed line in fig. 4 (b)) for a defined region in the RCF corresponding to a half cone beam divergence of ~10 . If we take this as the divergence of the narrow band component of the carbon ion beam, the conversion efficiency into this component can be estimated as 1%, which is significantly higher than reported in [13] and comparable to ref. [8 (a)].
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Noise and determinism in cardiovascular dynamics

Noise and determinism in cardiovascular dynamics

Given the clear evidence of (a) well-defined spectral peaks (implying the pres- ence of oscillatory processes) and (b) amplitude and frequency modulation, and synchronization effects (all indicating the existence of inter-oscillator in- teractions), it is natural to try to model the system with a set of oscillators [38] whose couplings [39] can be adjusted to try to reproduce the observed phenomena.

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Chickadee songs provide hidden clues to singers’ locations

Chickadee songs provide hidden clues to singers’ locations

Use of coincident reverberation cues for estimating source distance is complicated by the fact that both transmission loss and reverberation vary across habitats (Huisman & Attenborough, 1991; Richards & Wiley, 1980; Yang, Kang, Cheal, Van Renterghem, & Botteldooren, 2013), and as a function of source and receiver positions (Nelson & Stoddard, 1998; Padgham, 2004), such that a received spectral shape might be associated with different absolute distances in different habitats. For example, spectral peaks present in the bee note might be equal at a distance of 80 m in one environment, but not in a different habitat. Many environmental variables affect how songs attenuate and reverberate during transmission (Richards & Wiley, 1980; Wiley & Richards, 1978, 1982). Because most of the conditions that affect propagation along a direct path will also affect transmission of reverberated echoes along indirect paths, habitat-dependent effects on attenuation will be correlated with habitat-dependent effects on reverberation. Nevertheless, a listening bird must either account for possible habitat-dependent effects on received signals, or learn through experience how changes in spectral shape relate to variations in singer distance within a particular habitat, to accurately map coincident reverberation cues onto different source distances. This constraint applies to all other known auditory distance cues as well, and so does not require listening birds to possess any processing capacities beyond those that they are currently assumed to have. Habitat-dependent propagation effects are less likely to affect a listening bird’s ability to track a singer’s movements, because if a singer is stationary, approaching, or leaving while singing multiple songs, then the difference between reverberation and a directly received note will remain stable, increase, or decrease accordingly.
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Pharmacognostical Standardization Phytochemical Characterization and Pharmacological Studies of Selected
Herbal Anti-Neoplastics.

Pharmacognostical Standardization Phytochemical Characterization and Pharmacological Studies of Selected Herbal Anti-Neoplastics.

Spectral peaks of the compound AL – 168 III 19 Data showing the I.R Spectral peaks of the compounds LC – 180 I 20 Data showing the invitro cytotoxicity effects of Alangium 202 lamarckii [r]

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Interpretation of suprathermal emission at deuteron cyclotron harmonics from deuterium plasmas heated by neutral beam injection in the KSTAR tokamak

Interpretation of suprathermal emission at deuteron cyclotron harmonics from deuterium plasmas heated by neutral beam injection in the KSTAR tokamak

In this paper we address steady state ICE characterised by deuteron, as distinct from proton, cyclotron harmonic structure, which typically occurs during “phase 1”. Before doing so, let us contextualise our study by offering a brief account of the proton chirping ICE observed during “phase 2”. The proton chirping ICE observed during “phase 2” involves a fast redistribution of intensity across the fixed multiple cyclotron harmonics at which the ion cyclotron emission (ICE) is observed. Using particle- in-cell (PIC) [44] simulations [45], this chirping has been attributed to the rapidly changing spectral characteristics of the MCI which are caused by the rapidly decreasing local plasma density. This is turn is due to the motion of ELM filaments during the pedestal collapse. Chirping ICE spectral peaks in KSTAR plasmas are observed at harmonics of either the deuteron cyclotron frequency f cD , or the
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Clutter mitigation, multiple peaks, and high-order spectral moments in 35 GHz vertically pointing radar velocity spectra

Clutter mitigation, multiple peaks, and high-order spectral moments in 35 GHz vertically pointing radar velocity spectra

This study is a combined science and engineering effort de- signed to improve high-order moments estimated from Ka- band (35 GHz) vertically pointing radar Doppler velocity spectra by developing three different signal-processing meth- ods. First, a decluttering method identifies and removes clut- ter in the Doppler spectra. Hard targets produce narrow spec- tral peaks. Identifying clutter peaks is based on identifying large power drops between neighbouring velocity bins. In our observations, the narrow clutter peak occurred near zero velocity. After identifying narrow spectral peaks, a linear in- terpolation is performed to remove the narrow peak from the velocity spectra. All spectra void of clutter and those with mitigated clutter are used in the subsequent processing meth- ods. As an interesting side note, we found that a rotating an- tenna within 2 m of the Ka-band vertically pointing radar is causing the clutter to be Doppler shifted. We postulate re- flected waves bouncing off the rotating antenna cause the path length between the Ka-band antenna feed horn and the stationary targets to change from pulse to pulse, which ar- tificially changes the target range during the 2 s dwell pro- ducing a Doppler shift. Note that insects are hard targets and produce narrow peaks in Ka-band spectra with non-zero ve- locities as shown in Luke et al. (2008). Thus, insect clutter can be removed from spectra by identifying large drops in power between neighbouring velocity bins and then interpo- lating across these narrow peaks.
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Sputtered (Bax, Sr1-x)TiO3, BST, Thin Films on Flexible Copper Foils for Use as a Non-Linear Dielectric

Sputtered (Bax, Sr1-x)TiO3, BST, Thin Films on Flexible Copper Foils for Use as a Non-Linear Dielectric

XPS revealed the existence of copper, zinc, and oxygen on the PLPS surface evident by spectral peaks at binding energies corresponding to the 2p electrons of the metals and the 1s elec[r]

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A New Method for Identifying the Life Parameters via Radar

A New Method for Identifying the Life Parameters via Radar

It has been proved that the vital signs can be detected via radar. To better identify the life parameters such as respiration and heartbeat, a novel method combined with several signal processing techniques is presented. Firstly, to improve the signal-to-noise ratio (SNR) of the life signals, the signal accumulation technique by FFT is used. Then, to restrain the interferences produced by moving objects, a dual filtering algorithm (DFA) which is able to remove the interferences by tracing the interfering spectral peaks is proposed. Finally, the wavelet transform is applied to separate the heartbeat from the respiration signal. The method cannot only help to automatically detect the existence of human beings effectively, but also identifying the parameters like respiration, heart- beat, and body-moving signals significantly. Experimental results demonstrated that the method is very promising in identifying the life parameters via radar.
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Azo-Schiff Base Complexes Synthesis, Spectroscopic Characterization and Microbicide Studies

Azo-Schiff Base Complexes Synthesis, Spectroscopic Characterization and Microbicide Studies

ligand coordination mode can be established by comparing the complexes infrared spectra with the free ligand spectrum; the most important spectral peaks are presented in Table 2. Upon complexation, the spectra of all complexes except (10) and (11) showed that the absorption frequency of antipyrine carbonyl ν(C=O) group was shifted to a lower frequency by about 25-57 cm −1 and appeared in the region 1603-1635 cm −1 . This shift was accompanied by a decreasing in its intensity confirming the chelation of carbonyl oxygen atom with the metal ions 45 . In the spectra of all complexes the absorption frequency of azomethine ν(C=N)
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Identification and characterization of visual pigments in caecilians (Amphibia: Gymnophiona), an order of limbless vertebrates with rudimentary eyes

Identification and characterization of visual pigments in caecilians (Amphibia: Gymnophiona), an order of limbless vertebrates with rudimentary eyes

Only a single spectral class of photoreceptor was found in three caecilian species, Rhinatrema bivittatum, Typhlonectes natans and Geotrypetes seraphini, with mean absorbance peaks between 487–489nm. Consistent with this, the only expressed opsin detected in the eye of two caecilian species, T. natans and I. cf. kohtaoensis, belongs to the rod or Rh1 class of opsins that is expressed in rod photoreceptors throughout the vertebrate kingdom. No other classes of photoreceptors or expressed opsins were found and it is concluded that these caecilian species possess a rod-only retina, which agrees with previous research (Wake, 1985; Himstedt, 1995). Because cone opsins homologous with those of other vertebrates are found in members of the Urodela (salamanders) and Anura (frogs) (Rohlich and Szel, 2000; Takahashi et al., 2001; Sakikabara et al., 2002), it would appear that the loss of cone opsins, and cone photoreceptors, is a synapomorphy of Gymnophiona.
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DEVELOPMENT AND VALIDATION OF ULTRA VIOLET SPECTROPHOTOMETRIC METHOD FOR DETERMINATION OF ACID DISSOCIATION CONSTANT OF TRAMADOL HYDROCHLORIDE

DEVELOPMENT AND VALIDATION OF ULTRA VIOLET SPECTROPHOTOMETRIC METHOD FOR DETERMINATION OF ACID DISSOCIATION CONSTANT OF TRAMADOL HYDROCHLORIDE

A UV-VIS Spectrophotometer, model Shimadzu 1800 (Japan) was employed with spectral pair of matched quartz cells of 1cm optical path length. Buffer solution was used for preparing dilutions. Glassware used in each procedure were rinsed thoroughly with acetone and dried in hot air oven. All other reagents and chemicals were of analytical reagent grade.

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High electron mobility, quantum Hall effect and anomalous optical response in atomically thin InSe

High electron mobility, quantum Hall effect and anomalous optical response in atomically thin InSe

To  gain  further  information  about  few‐layer  InSe,  we  employed  photoluminescence  (PL)  spectroscopy.  Fig.  4  shows  the  PL  response  found  for  hBN‐encapsulated  InSe  crystals  using  laser  excitation  at  photon  energies  of  2.3,  2.7  and  3.8  eV  (see  Methods).  We  studied  2D  crystals  with  every N from 1 to 8. For 2 to 8 layer InSe, their PL spectra showed two lines, A at a lower and B at a  higher  energy,  whereas  monolayer  InSe  exhibited  only  the  high‐energy  peak.  The  inset  of  Fig.  4a  plots the energy  of  the A and  B lines for different N, with dots corresponding to  the  measured PL  and  open  squares  to  the  DFT  calculations  described  in  Supplementary  Section  7.  The  progressive  blue shift of the A line with decreasing N follows the trend reported previously 17,18 . To highlight the  disappearance  of  the  A  line  in  1L  InSe,  Fig.  4b  shows  a  PL  intensity  map  for  a  device  containing  mono‐  and  bi‐  layer  regions.  There  was  no  discernable  PL  response  in  the  A  spectral  region  anywhere within the 1L area.  
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John Tyndall: Peaks and troughs

John Tyndall: Peaks and troughs

By that time Tyndall might have had some idea of the direction his speech would take, since we know that in January he had been in touch with Lange enquiring about the revised edition of[r]

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Development of the Composition and Method of Producing a Liquid Complex Fertilizers with a Stabilizing Additive

Development of the Composition and Method of Producing a Liquid Complex Fertilizers with a Stabilizing Additive

IR spectral analysis of liquid complex fertilizers was conducted on the instrument IR spectrometer Shimadzu IR Prestige-21. In table 4 and fig.4 shows the main peaks according to the results of IR spectral analysis of liquid complex fertilizers.

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Changes detection of serum Raman spectroscopy at different stages of lung cancer using spectral parameters and regression tree

Changes detection of serum Raman spectroscopy at different stages of lung cancer using spectral parameters and regression tree

In serum spectrum, three Raman peaks are almost the same as resonance Raman spectrum of beta carotene in carbon tetrachloride solution, whether peak location or intensity distribution[10]. We assumed that they were derived from beta carotene emission. Beta carotene is a kind of carotenoids and can be translated into vitamin A. In epidemiology, studies showed that the incidence of cancer and the content of beta carotene are closely relevant. The higher the content of beta carotene, the less incidence of cancer[11]. And some researches demonstrated that beta carotene, to some extent, can restrain the growth and progression of tumor cells[12]. Our result indicated that the content of beta carotene decreased with aggravation of lung cancer. It means that beta carotene has close relationship with cancer. Such conclusion agrees well with former studies in chromatogram and epidemiology.
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Mass spectrometric survey of peptides in cephalopods with an emphasis on the FMRFamide related peptides

Mass spectrometric survey of peptides in cephalopods with an emphasis on the FMRFamide related peptides

Although most of the peaks in the mass region of m/z 1000–5000 can be attributed to peptides, a group of peaks ranging from m/z 500 to m/z 900 are often observed in cellular samples, especially in nerve tissues, and are generally attributed to phospholipids (Li et al., 1998; Garden and Sweedler, 2000). We attempted to determine whether the assignment of these low-molecular-mass peaks to lipids is correct by accurate comparisons with expected lipids in this model system. The squid giant axon has proved a useful preparation for examining the physiological and biochemical properties of axonal processes such as impulse propagation, axonal transport and their link to behavior (Baker, 1984; Preuss and Gilly, 2000; Neumeister et al., 2000), and an understanding of the role of lipids in the function of this nerve is of considerable importance. An essential step towards this goal is to examine the molecular composition of these lipid components of the squid giant axon. Accordingly, several studies have investigated lipid metabolism in various regions of squid giant nerve fibers and characterized lipid composition in different squid nerve tissues (Camejo et al., 1969; Tanaka et al., 1987; Yamaguchi et al., 1987). More recently, several reports describe the use of the MALDI MS technique for lipid Table 2. Comparison of a section of the FMRFa gene sequence from Cephalopods
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