Novel Method For Suppression Research Articles

Comprehensive analysis on the magnetic field error of a K–Rb–21Ne comagnetometer with low-frequency bias magnetic field sensitivity

The spin-exchange relaxation-free comagnetometer (SERFC) is of important research value compared to existing high-precision gyroscopes because of its extremely high theoretical limit sensitivity and long-term stability, in which one significant limiting factor is the magnetic field error. First, the relationship between the magnetic field gradient and the nuclear spin relaxation mechanism is introduced into the frequency response and steady-state response models of SERFC. Then, a novel method for suppression of the low-frequency magnetic field error based on the modified bias magnetic field sensitivity model is proposed. Finally, the effectiveness of the proposed suppression methods is demonstrated by optimizing the cell temperature, pump light power, and compensation magnetic field gradient to increase the suppression factor by 72.19%, 20.24%, and 69.86%, and the corresponding bias instability increased by 55.41%, 20.84%, and 27.63%, respectively. This study contributes to improving the long-term zero bias stability of the SERFC.

Synergy of regulating zinc electrodeposition and suppressing hydrogen evolution by functional coating layer for highly reversible zinc anode

The Zn metal anode for aqueous Zn-ion batteries (AZIB) has attracted intensive attention owing to its high theoretical capacity and low cost. However, two intrinsic problems, including hydrogen evolution induced by low redox overpotential and unordered dendrite growth owing to its physiochemical properties, can contribute to futile consumption of Zn anode and safety failure, which hinder the practical application of AZIB. Herein, a strategy of introducing organic protective layer (P3HT) is demonstrated to be effective to segregate electrode and electrolyte for prolonged cycling life. The P3HT with hydrophobic property can block the access of H2O, benefit the Zn2+ transport, and regulate the electrical field distribution and Zn2+ flux field distribution around Zn surface for homogeneous Zn metal deposition. The optimized OPZn anode can present excellent stripping/plating cycles (1000 h at 1 mA cm−2 for 1 mAh cm−2; 900 h at 3 mA cm−2 for 1 mAh cm−2), deliver stable rate performance, and enable good full OPZn|HCNF battery. This work provides a novel method for suppression of hydrogen evolution and guidance of uniform Zn ions deposition during the electrochemical process.

Reducing Sensor Noise in MEG and EEG Recordings Using Oversampled Temporal Projection.

Here, we review the theory of suppression of spatially uncorrelated, sensor-specific noise in electro- and magentoencephalography (EEG and MEG) arrays, and introduce a novel method for suppression. Our method requires only that the signals of interest are spatially oversampled, which is a reasonable assumption for many EEG and MEG systems. Our method is based on a leave-one-out procedure using overlapping temporal windows in a mathematical framework to project spatially uncorrelated noise in the temporal domain. This method, termed "oversampled temporal projection" (OTP), has four advantages over existing methods. First, sparse channel-specific artifacts are suppressed while limiting mixing with other channels, whereas existing linear, time-invariant spatial operators can spread such artifacts to other channels with a spatial distribution which can be mistaken for one produced by an electrophysiological source. Second, OTP minimizes distortion of the spatial configuration of the data. During source localization (e.g., dipole fitting), many spatial methods require corresponding modification of the forward model to avoid bias, while OTP does not. Third, noise suppression factors at the sensor level are maintained during source localization, whereas bias compensation removes the denoising benefit for spatial methods that require such compensation. Fourth, OTP uses a time-window duration parameter to control the tradeoff between noise suppression and adaptation to time-varying sensor characteristics. OTP efficiently optimizes noise suppression performance while controlling for spatial bias of the signal of interest. This is important in applications where sensor noise significantly limits the signal-to-noise ratio, such as high-frequency brain oscillations.

Composite lateral electric field excited piezoelectric resonator

The novel method of suppression of parasitic oscillations in lateral electric field excited piezoelectric resonator is suggested. Traditionally such resonator represents the piezoelectric plate with two electrodes on one side of the plate. The crystallographic orientation of the plate is selected so that the tangential components of electric field excite bulk acoustic wave with given polarization travelling along the normal to the plate sides. However at that the normal components of field excite the parasitic Lamb waves and bulk waves of other polarization which deteriorate the resonant properties of the resonator. In this work we suggest to separate the source of the HF electric field and resounded piezoelectric plate by air gap. In this case the tangential components of the field in piezoelectric plate do not practically weaken but normal components significantly decrease. This method is realized on the composite resonator having the structure “glass plate with rectangular electrodes – air gap – plate of 128 Y-X lithium niobate.” It has been shown that there exist the optimal value of the width gap which ensure the good quality of series and parallel resonances in frequency range 3–4MHz with record values of Q-factor of ∼15,000 in both cases.

Phase-Based Clutter Identification in Spectra of Weather Radar Signals

A novel method for suppression of ground clutter (GC) in weather radar is presented. The novel identification scheme is entirely phase based, unlike power-based schemes that are generally used. GC contributions to the Doppler spectrum are identified from the differential phase between complex spectral coefficients of two spectra estimated for odd- and even-indexed half-sequences of the original time series. Phase values near zero are used as indicators of clutter contributions for Doppler bins close to zero velocity. Indicated Doppler bins are notched from the original spectrum, and the moments are then obtained. The identification scheme is motivated by spectra of an electronically steered phased array of the National Weather Radar Testbed (NWRT) and requires a sufficient number of pulses/samples for spectral analyses. However, the method can be used with a mechanically steered antenna with an appropriate adjustment compensating smearing due to antenna rotation. The method was tested on several NWRT data sets obtained in clear air and in precipitation. One example of clutter-filtered power in precipitation is shown here. There is no baseline for comparison, as the NWRT does not have clutter filtering at the present time. Nonetheless, for a comparison of power- and phase-based identification schemes, a power-based clutter filter similar to the one used by the National Weather Service on the network of mechanically steerable Weather Surveillance Doppler radars WSR-88Ds is implemented on NWRT and used as a preliminary baseline for comparison.

Parity effect in superconducting aluminum single electron transistors with spatial gap profile controlled by film thickness

We propose a novel method for suppression of quasiparticle poisoning in Al Coulomb blockade devices. The method is based on creation of a proper energy gap profile along the device. In contrast to the previously used techniques, the energy gap is controlled by the film thickness. Our transport measurements confirm that the quasiparticle poisoning is suppressed and clear 2e periodicity is observed only when the island is made much thinner than the leads. This result is consistent with the existing model and provides a simple method to suppress quasiparticle poisoning.

Suppression of diagonal peaks in three-dimensional protein NMR TROSY-type HCCH correlation experiments.

A novel method for suppression of (13)C-(13)C diagonal peaks without sensitivity loss in three-dimensional HCCH TROSY-type NMR correlation experiments involving aromatic side chains in proteins (Pervushin et al., J. Am. Chem. Soc. 120, 6394-6400 (1998)) is presented. The key element is a spin-state-selective filter in the (13)C-(13)C mixing sequence with the dual effect of selecting the TROSY resonance in the preceding evolution period and interchanging TROSY and anti-TROSY resonances. The cross peaks are invariant to this filter but diagonal peak coherence gets concentrated on the anti-TROSY transition so that it can be eliminated by a (13)C --> (1)H TROSY transfer element. The new method is demonstrated using a (13)C,(15)N-labeled protein sample, RAP 18-112 (N-terminal domain of alpha(2)-macroglobulin receptor associated protein), at 750 MHz.

A Novel Method for Suppression of the Abnormal Fischer Indole Synthesis

A Novel Method for Suppression of the Abnormal Fischer Indole Synthesis

A novel method for suppression of the abnormal Fischer indole synthesis

A method is described for the use of the Fischer indole synthesis to prepare 7-hydroxy-indoles in good yield. The method involves the construction of a 4-aminobenzoxazine and removal of the N-O tether after the indole has been formed.

A Novel Method for Suppression of Aliasing Ghosts

This paper proposes a “half-sample delay switching” to suppress aliasing ghosts caused by finite frequency sampling without the clumsiness of a sharp anti-aliasing filter.