Logarithmic Axis Research Articles

Multi-shelf graphic equalizer

A graphic equalizer (GEQ) is a standard tool in audio production and effect design. Adjustable gain control frequencies are fixed along the logarithmic frequency axis, and an automatic design method matches the magnitude response to them whenever target gains are changed. Most commonly, the GEQ comprises a set of peak filters centered an octave apart, possibly with a shelving filter at the bottom and top of the frequency range. While accurate designs were proposed, the dynamic range is typically limited to 24 dB. In this paper, we propose two innovations. First, we introduce a GEQ based on shelving filters only, which can cover an extensive dynamic range of over 60 dB. Secondly, we introduce an order-switching technique that combines shelf filters of different order. We demonstrate the performance and advantages of the proposed filter with design examples. The proposed shelf-filter-based GEQ offers a wider dynamic range and a smoother magnitude response than traditional peak-filter-based GEQ designs.

Photothermal enhanced fluorescence quenching of Tb-norfloxacin for ultrasensitive human epididymal 4 detection.

A fluorescence quenching enhanced immunoassay has been developed to achieve ultrasensitive recognition of human epididymal 4 (HE4) modifying the fluorescence quencher. The carboxymethyl cellulose sodium-functionalized Nb2C MXene nanocomposite (CMC@MXene) was firstly introduced to quench the fluorescence signal of the luminophore Tb-Norfloxacin coordination polymer nanoparticles (Tb-NFX CPNPs). The Nb2C MXene nanocomposite as fluorescent nanoquencher inhibits the electron transfer between Tb and NFX to quench the fluorescent signal by coordinating the strongly electronegative carboxyl group on CMC with Tb (III) of Tb-NFX complex. Simultaneously, due to the superior photothermal conversion capability of CMC@MXene, the fluorescence signal has been further weakened by the photothermal effect driven non-radiative decay of the excited state under near-infrared laser irradiation. The constructed fluorescent biosensor based on CMC@MXene probe finally realized the enhanced fluorescence quenching effect, and achieved ultra-high sensitivity and selective detection of HE4, exhibiting a wide linear relationship with HE4 concentration on the logarithmic axis in the range of 10-5 to 10ng/mL and a low detection limit of 3.3fg/mL (S/N = 3). This work not only provides an enhanced fluorescent signal quenching method for the detection of HE4, but also provides novel insights for the design of fluorescent sensor toward different biomolecules.

Occurrence Rate of Hot Jupiters Around Early-type M Dwarfs Based on Transiting Exoplanet Survey Satellite Data

We present an estimate of the occurrence rate of hot Jupiters (7 R ⊕ ≤ R p ≤ 2 R J, 0.8 ≤ P b ≤ 10 days) around early-type M dwarfs based on stars observed by the Transiting Exoplanet Survey Satellite (TESS) during its primary mission. We adopt stellar parameters from the TESS Input Catalog and construct a sample of 60,819 M dwarfs with 10.5 ≤ T mag ≤ 13.5, effective temperatures 2900 ≤ T eff ≤ 4000 K, and stellar masses 0.45 ≤ M * ≤ 0.65 M ⊙. We conduct a uninformed transit search using a detection pipeline based on the box least square search and characterize the searching completeness through an injection and recovery experiment. We combine a series of vetting steps including light centroid measurement, odd/even and secondary eclipse analysis, rotation and transit period synchronization tests as well as inspecting the ground-based photometric, spectroscopic, and imaging observations. Finally, we find a total of nine planet candidates, all of which are known TESS objects of interest. We obtain an occurrence rate of 0.27% ± 0.09% for hot Jupiters around early-type M dwarfs that satisfy our selection criteria. Compared with previous studies, the occurrence rate of hot Jupiters around early-type M dwarfs is smaller than all measurements for FGK stars, although they are consistent within 1σ–2σ. There is a trend that the occurrence rate of hot Jupiters has a peak at G dwarfs and falls toward both hotter and cooler stars. Combining results from transit, radial velocity, and microlensing surveys, we find that hot Jupiters around early-type M dwarfs possibly show a steeper decrease in the occurrence rate per logarithmic semimajor axis bin () when compared with FGK stars.

Slope Identification and Decision Making: A Comparison of Linear and Ratio Graphs.

Applied behavior analysts have traditionally relied on visual analysis of graphic data displays to determine the extent of functional relations between variables and guide treatment implementation. The present study assessed the influence of graph type on behavior analysts' (n = 51) ratings of trend magnitude, treatment decisions based on changes in trend, and their confidence in decision making. Participants examined simulated data presented on linear graphs featuring equal-interval scales as well as graphs with ratio scales (i.e., multiply/divide or logarithmic vertical axis) and numeric indicators of celeration. Standard rules for interpreting trends using each display accompanied the assessment items. Results suggested participants maintained significantly higher levels of agreement on evaluations of trend magnitude and treatment decisions and reported higher levels of confidence in making decisions when using ratio graphs. Furthermore, decision making occurred most efficiently with ratio charts and a celeration value. The findings have implications for research and practice.

Prediction Method of Water Absorption of Soft Rock Considering the Influence of Composition, Porosity, and Solute Quantitatively

The study of water absorption of soft rock is of great significance to the prevention engineering disasters. However, the research on the prediction method of water absorption of soft rock considering the influence of composition, porosity, and solute is insufficient. Aiming to solve the above problem, water absorption tests are carried out by synthesizing soft rocks and water solutions. Then, the prediction model of water absorption of soft rock is established through quantitative analysis of water absorption data and compared with the water absorption characteristics of natural rock to verify the reliability of the model. The results show that the changes in water content and water absorption velocity of soft rock with time obey the second-order exponential attenuation function and the linear function (double logarithmic coordinates axis), respectively. The types of cations and anions and the type and content of clay minerals have the greatest influence on the process of rock water absorption. In addition, the water absorption prediction model could better predict the water absorption process of natural rock. The research results solve the problem of insufficient research on the soft rock water absorption prediction method considering the influence of composition, porosity and solute.

Hybridization chain reaction for regulating surface capacitance of organic photoelectrochemical transistor toward sensitive miRNA detection

Photon-enabled bioelectronics has long been pursued in modern electronics due to their non-contact, remote-control, and even self-powered function interfacing the biological world with semiconductor devices. The debuting organic photoelectrochemical transistor (OPECT) relies on the photovoltage generated by the semiconductors to modulate the channel conductance, which enables light-fueled operation at zero gate bias. Inspired by the insulating nature of macrobiomolecules and surface capacitance mechanism, herein we demonstrate the biological regulation of the surface capacitance towards new OPECT biodetection, which was exemplified by a CdS quantum dots/TiO2 nanotubes photoanode accommodating hybridization chain reaction (HCR) amplification with the target of biomarker miRNA-17. Formation of the non-conducting DNA layer from the miRNA-17-oriented HCR could decrease the surface capacitance and increase the corresponding fractional potential drop, shifting the transfer curve horizontally to higher gate voltage and thus producing different drain currents. The OPECT biosensor exhibited a linear relationship with the miRNA-17 concentration on the logarithmic axis in the range from 1 pm. to 10 μm with a detection limit of 1 pm. This work not only represented a generic methodology of miRNA detection, but also provided a universal mechanism for the operation of advanced OPECT bioanalytics.

Laser intensity noise evaluation system for space-based gravitational wave detection

The space-based gravitational wave detection can acquire the gravitational wave source information with larger characteristic mass and scale, forming a complementary detection scheme with ground-based gravitational wave detection, primordial gravitational wave detection, and pulsar gravitational wave detection. The space-based gravitational wave detection is based on a long-distance laser interference device, which mainly detects gravitational wave signals in a frequency range of 0.1 mHz–1 Hz. The noise evaluation and noise suppression of the laser light source system directly affect the detection sensitivity. In this work, based on low-noise photoelectric detection, a very low-frequency laser intensity noise test and evaluation system is constructed with high-precision digital multimeter, software control and algorithm programming of the host computer. The laser intensity noise can be converted into the fluctuation of the current signal by utilizing the photodiode, and the current signal is converted into the voltage signal and amplified by the transimpedance circuit. Thus the high-frequency interference components are filtered out by a passive low-pass filtering, and the extremely low-frequency noise components are retained. According to the definition of shot noise, it can be known that the photocurrent injected into the detector is inversely proportional to the shot noise, so at least 5 mW laser is chosen for photoelectric detection. After controlling the high-precision digital multimeter through LabVIEW software programming, the acquisition is detected. The output voltage signal by the laser is subjected to the fast Fourier transform and logarithmic frequency axis power spectral density estimation algorithm for noise evaluation in the frequency domain, forming a complete laser intensity noise evaluation and measurement system. The 0.1 mHz–1 Hz frequency band laser intensity noise evaluation is finally obtained. The experimental results show that the noise of the high-precision multimeter in a frequency band of 0.1 mHz–1 Hz is lower than 5×10<sup>–5</sup> V/Hz<sup>1/2</sup>; the noise of the detector electronics ina frequency band of 0.1 mHz–1 Hz is lower than 4×10<sup>–5</sup> V/Hz<sup>1/2</sup>. The electronic noise of the high-precision multimeters and the detectors meet the requirements for space gravitational wave detection. The experimental results show that the 0.1 mHz–1 Hz frequency band laser intensity noise evaluation system we built meets the needs of space-based gravitational wave detection program, and provides an important foundation for building a laser source that meets the needs of space-based gravitational wave detection.

ОСОБЕННОСТИ РАСПРЕДЕЛЕНИЯ СОБЫТИЙ ПО МНОЖЕСТВЕННОСТИ ВТОРИЧНЫХ ЧАСТИЦ В ЗАВИСИМОСТИ ОТ ЭНЕРГИИ СТОЛКНОВЕНИЯ И АССИМЕТРИЧНОСТИ СТАЛКИВАЮЩИХСЯ РЕЛЯТИВИСТСКИХ ЯДЕР

To search for signals of the phase transition of matter from the hadronic state to the quark­gluon plasma, interactions with extreme characteristics are studied. The study of the dependence of the av­erage multiplicity on the projectile energy for sulfur and silicon nuclei with energies of 3.7 AGeV, 14 AGeV, and 200 AGeV has been carried out. Experimental data on inelastic interactions with the nuclei of the NIKFI BR­2 emulsion obtained at the SPS at CERN and at the Synchrophasotron at JINR. To take into account fluctuations in the initial conditions of the nucleus­nucleus interaction, the events were divided into central and peripheral ones. A comparative analysis of the average multiplicity with heavy and light nuclei of the photographic emulsion is presented. The multiplicity increase factor has an almost linear increase in energy (on the logarithmic axis) for all events, except for the central interactions of sulfur nuclei with heavy emulsion nuclei at 200 AGeV. These events are explosive events, which give a flux of secondary particles in a narrow range of average pseudo­rapidity and significantly shifted towards low values <η>. The analysis of events of complete destruction of the projectile nucleus is presented. Such events are considered as events in which the most favorable conditions are created for the formation of a quark­gluon plasma.

Smoke Evacuation Filters After the COVID-19 Pandemic

Smoke Evacuation Filters After the COVID-19 Pandemic

Dome patterns in pelagic size spectra reveal strong trophic cascades

In ecological communities, especially the pelagic zones of aquatic ecosystems, certain body-size ranges are often over-represented compared to others. Community size spectra, the distributions of community biomass over the logarithmic body-mass axis, tend to exhibit regularly spaced local maxima, called “domes”, separated by steep troughs. Contrasting established theory, we explain these dome patterns as manifestations of top-down trophic cascades along aquatic food chains. Compiling high quality size-spectrum data and comparing these with a size-spectrum model introduced in this study, we test this theory and develop a detailed picture of the mechanisms by which bottom-up and top-down effects interact to generate dome patterns. Results imply that strong top-down trophic cascades are common in freshwater communities, much more than hitherto demonstrated, and may arise in nutrient rich marine systems as well. Transferring insights from the general theory of non-linear pattern formation to domes patterns, we provide new interpretations of past lake-manipulation experiments.

Power law attenuation modeled as multiple relaxation

Wave equations with non-integer order derivatives may model power law behavior in medical and sediment acoustics. As experiments only support a finite bandwidth, there is a limit to how much physical insight that can be gained from such models. Other ways to model a power law are with a fractional heat law, hierarchical ladder models for polymer chains, and the non-Newtonian rheology of grain shearing. Multiple relaxation processes may be motivated by a hierarchy of substructures at different scales. It is also inherent in soft glassy materials, such as cells, with disordering and metastability. Even the Biot model with contact squirt flow and shear drag (BICSQS) may be interpreted as a multiple relaxation model. A weighted sum of relaxation processes will approximate a power law over a limited band, and an even distribution of relaxation frequencies on a logarithmic frequency axis, and with equal relaxation strengths, will give a power law attenuation with unit power, y = 1. This can be generalized to other power laws if the contribution from each relaxation process varies in proportion to the relaxation frequency to the power of y - 1. This scale-invariant distribution may hint at some fractal medium properties.

Development of Prony series models based on continuous relaxation spectrums for relaxation moduli determined using creep tests

Prony series models have been widely utilized to represent relaxation moduli. However, negative model parameters and wavy fitting curves are common observations of Prony series models of relaxation moduli constructed based on creep tests without establishing a continuous relaxation spectrum. This study developed a method of constructing relaxation modulus models in the form of Prony series based on creep test data via establishing continuous spectrums of relaxation times. Uniaxial compressive creep tests were performed on two types of asphalt mixtures at five test temperatures. The measured creep compliances at every test temperature were modeled using the generalized Kelvin model with two Kelvin elements, which provided excellent model fitting with R2 values larger than 0.99. The modeled creep compliances at every temperature were converted into the relaxation moduli according to the constitutive relations of the generalized Kelvin model. Master curves of the relaxation moduli were constructed using the modified power law model. The continuous spectrum of relaxation times was therefore established for each mixture type. The relaxation modulus model in terms of the continuous relaxation spectrum was approximated using the form of Prony series. Prony series models with various terms were constructed for each mixture type; the parameters of these Prony series models were all positive. It was demonstrated that, when specifying one relaxation time per decade equidistantly on a base-10 logarithmic axis, the constructed Prony series model for each mixture type had a reasonable number of terms and generated a fitting curve of the relaxation modulus with negligible waviness and an R2 value larger than 0.99.The method developed in this study provided an effective solution to build a Prony series model of the relaxation modulus with a limited number of terms, guaranteed positive model parameters, an excellent goodness of fit, and a fitting curve with negligible waviness.

Log-polar mapping-based scale space tracking with adaptive target response

Correlation filter-based tracking has exhibited impressive robustness and accuracy in recent years. Standard correlation filter-based trackers are restricted to translation estimation and equipped with fixed target response. These trackers produce an inferior performance when encountered with a significant scale variation or appearance change. We propose a log-polar mapping-based scale space tracker with an adaptive target response. This tracker transforms the scale variation of the target in the Cartesian space into a shift along the logarithmic axis in the log-polar space. A one-dimensional scale correlation filter is learned online to estimate the shift along the logarithmic axis. With the log-polar representation, scale estimation is achieved accurately without a multiresolution pyramid. To achieve an adaptive target response, a variance of the Gaussian function is computed from the response map and updated online with a learning rate parameter. Our log-polar mapping-based scale correlation filter and adaptive target response can be combined with any correlation filter-based trackers. In addition, the scale correlation filter can be extended to a two-dimensional correlation filter to achieve joint estimation of the scale variation and in-plane rotation. Experiments performed on an OTB50 benchmark demonstrate that our tracker achieves superior performance against state-of-the-art trackers.

3-D Topo Surface Visualization of Acid–Base Species Distributions: Corner Buttes, Corner Pits, Curving Ridge Crests, and Dilution Plains

Species TOPOS is a free software package for generating three-dimensional (3-D) topographic surfaces (“topos”) for acid–base equilibrium studies. This upgrade adds 3-D species distribution topos to earlier surfaces that showed pH and buffer capacity behavior during titration and dilution procedures. It constructs topos by plotting computed α values above a composition grid with volume of NaOH added as the x axis and overall system dilution as the y axis. The systematic shift from protonated to deprotonated forms is clearly visualized on a linear z axis. Because pH and buffer capacity surfaces accompany the species topos, it is easy to see their interrelationships. On the basis of their graphical appearance, features on species topos have been named corner buttes, corner pits, curving ridge crests, and dilution plains. Ramps connecting surface features are linear when tied to additions of NaOH and logarithmic when associated with the logarithmic dilution axis. The amphiprotic behavior of water is demonstra...

Different shapes of impurity concentration profiles formed by long-range interstitial migration

A model of interstitial impurity migration is proposed which explains the redistribution of ion-implanted boron in low-temperature annealing of nonamorphized silicon layers. It is supposed that nonequilibrium boron interstitials are generated either in the course of ion implantation or at the initial stage of thermal treatment and that they migrate inward and to the surface of a semiconductor in the basic stage of annealing. It is shown that the form of the “tail” in the boron profile with the logarithmic concentration axis changes from a straight line if the average lifetime of impurity interstitials is substantially shorter than the annealing duration to that bending upwards for increasing lifetime. The calculated impurity concentration profiles are in excellent agreement with the experimental data describing the redistribution of implanted boron for low-temperature annealing at 750[Formula: see text]C for 1[Formula: see text]h and at 800[Formula: see text]C for 35[Formula: see text]min. Simultaneously, the experimental phenomenon of incomplete electrical activation of boron atoms in the “tail” region is naturally explained.

Spatial Up-Scaling Correction for Leaf Area Index Based on the Fractal Theory

The scaling effect correction of retrieved parameters is an essential and difficult issue in analysis and application of remote sensing information. Based on fractal theory, this paper developed a scaling transfer model to correct the scaling effect of the leaf area index (LAI) estimated from coarse spatial resolution image. As the key parameter of the proposed model, the information fractal dimension (D) of the up-scaling pixel was calculated by establishing the double logarithmic linear relationship between D-2 and the normalized difference vegetation index (NDVI) standard deviation (σNDVI) of the up-scaling pixel. Based on the calculated D and the fractal relationship between the exact LAI and the approximated LAI estimated from the coarse resolution pixel, a LAI scaling transfer model was established. Finally, the model accuracy in correcting the scaling effect was discussed. Results indicated that the D increases with increasing σNDVI, and the D-2 was highly linearly correlated with σNDVI on the double logarithmic coordinate axis. The scaling transfer model corrected the scaling effect of LAI with a maximum value of root-mean-square error (RMSE) of 0.011. The maximum absolute correction error (ACE) and relative correction error (RCE) were only 0.108% and 8.56%, respectively. The spatial heterogeneity was the primary cause resulting in the scaling effect and the key influencing factor of correction effect. The results indicated that the developed method based on fractal theory could effectively correct the scaling effect of LAI estimated from the heterogeneous pixels.

Linear and log frequency rippled spectra

Roy Patterson’s Ph.D. dissertation investigated the pitch-shift of the residue and pitch perception has been a significant topic of interest to Roy ever since. I had the good fortune of collaborating with Roy on several studies involving pitch perception, especially on what we called regular interval stimuli (RIS), most notably iterated rippled noise (IRN). In addition to IRN stimuli which are characterized as stimuli with regularly spaced spectral peaks and valleys on a linear frequency axis, many studies have investigated stimuli that have regularly spaced spectral peaks and valleys on a logarithmic axis. Both set of stimuli produce a timbre/pitch-like sound quality. In some cases the sound quality of the two types of stimuli are difficult to perceptually separate. While RIS models of pitch processing (e.g., autocorrelation-based models) can account for many of the IRN pitch data, it is not clear what mechanisms produce the timbre/pitch-like qualities of log-frequency, rippled-spectra stimuli. The current paper involves three experiments designed to better understand auditory processing of rippled-spectra stimuli in order to determine if there may be some common perceptual elements that underlie the perception of such stimuli. [Research supported by the AFOSR.]

The Research of the Logarithmic Spiral Axis and NC Machining

The characteristics of surface connection include high fatigue strength, high centering ability, easy dismantling and long life. According to these characteristics and based on the analysis of logarithmic spiral equation, the article explores a new technique of the matched logarithmic spiral profile connection to facilitate efficiently by formulating the machining process and analysing the part technology to determine the geometric modeling, tool path and simulation of NC machining graph and to inspect the process of Logarithmic spiral axes CNC Machining Center and CMM.

0.5Tm이하에서의 AZ31 마그네슘합금의 크리이프 변형과 단시간 파단수명예측

The initial strain, the applied stress exponent, the activation energy, and rupture time in AZ31 magnesium alloy have been measured in order to predict the deformation mechanism and rupture life of creep over the temperature range of 423-443K. Creep tests were carried out under constant applied stress and temperature, and the lever type tester and automatic temperature controller was used for it, respectively. The experimental results showed that the applied stress exponent was about 9.74, and the activation energy for creep, 113.6KJ/mol was less than that of the self diffusion of Mg alloy including aluminum. From the results, the mechanism for creep deformation seems to be controlled by cross slip at the temperature range of 423-443K. Also the higher the applied stress and temperature, the higher the initial strain. And the rupture time for creep decreased as quadratic function with increasing the initial strain in double logarithmic axis.

Some Space–Time Spectral Analyses of Tropical Convection and Planetary-Scale Waves

Abstract Three aspects of space–time spectral analysis are explored for diagnosis of the organization of tropical convection by the Madden–Julian oscillation (MJO) and other equatorial wave modes: 1) definition of the background spectrum upon which spectral peaks are assessed, 2) alternate variance preserving display of the spectra, and 3) the space–time coherence spectrum. Here the background spectrum at each zonal wavenumber is assumed to result from a red noise process. The associated decorrelation time for the red noise process for tropical convection is found to be half as long as for zonal wind, reflecting the different physical processes controlling each field. The significance of spectral peaks associated with equatorial wave modes for outgoing longwave radiation (OLR), which is a proxy for precipitating deep convection, and zonal winds that stand out above the red background spectrum is similar to that identified using a background spectrum resulting from ad hoc smoothing of the original spectrum. A variance-preserving display of the space–time power spectrum with a logarithmic frequency axis is useful for directly detecting Kelvin waves (periods 5–15 days for eastward zonal wavenumbers 1–5) and for highlighting their distinction from the MJO. The space–time coherence of OLR and zonal wind is predominantly associated with the MJO and other equatorial waves. The space–time coherence is independent of estimating the background spectrum and is quantifiable; thus, it is suggested as a useful metric for the MJO and other equatorial waves in observations and simulations. The space–time coherence is also used to quantify the association of Kelvin waves in the stratosphere with convective variability in the troposphere and for detection of barotropic Rossby–Haurwitz waves.