Phase Increment Research Articles

Phase transformation and electrochemical hydrogen storage performances of La3RMgNi19 (R = La, Pr, Nd, Sm, Gd and Y) alloys

Adjusting the rare earth (RE) compositions in the RE–Mg–Ni alloys can effectively improve the electrochemical hydrogen storage performances of the alloy electrodes. Herein, A5B19 type hydrogen storage alloys with the elemental composition of La3RMgNi19 (R = La, Pr, Nd, Sm, Gd and Y) were prepared by induction melting and subsequent annealing. The phase transformation and electrochemical hydrogen storage performances of La3RMgNi19 alloys were investigated in detail. X-ray diffraction analysis shows that La3RMgNi19 alloys contains AB5, A2B7 (Ce2Ni7 and Gd2Co7) and A5B19 (Pr5Co19 and Ce5Co19) phases, and the increase of annealing temperature obviously reduces the phase abundance of LaNi5 phase. Sm, Gd and Y contribute to the formation of A5B19 phase, especially Ce5Co19, and Pr and Nd promote the formation of A2B7 phase for La3RMgNi19 alloys. With increasing annealing temperature, the maximum discharge capacity (Cmax) of La3RMgNi19 alloy electrodes first increases and then decreases, and the highest value of Cmax is achieved as the annealing temperature is 1223 K. This evolution trend of the Cmax is inversely proportional to that of LaNi5 phase abundance. The substation of La by Pr, Nd, Sm, Gd or Y causes the decrease of Cmax, which is mainly ascribed to the decrease of cell volume. Due to the decrement of LaNi5 phase, the cycling stability increases at first when the annealing temperature is below 1223 K. However, when annealing temperate further increases to 1273 K, the cycling stability decreases, which is caused by the increment of LaNi5 phase. It is worth noting that the phase composition (LaNi5 phase abundance) plays more important role than other factor. The slight decrement of high-rate dischargeability resulted from the substitution of La by Pr, Nd, Sm, Gd or Y should be attributed to the combined effect of advantageous and disadvantageous factors.

Comparative analysis of the performance of laser Doppler systems using maximum likelihood and phase increment methods

This paper presents a comparative analysis of the errors of two alternative methods of estimating the central frequency of signals of laser Doppler systems, one of which is based on the maximum likelihood criterion and the other on the so-called pulse-pair technique. Using computer simulation, the standard deviations of the Doppler signal frequency from its true values are determined for both methods and plots of the ratios of these deviations as a measure of the accuracy gain of one of them are constructed. The results can be used by developers of appropriate systems to choose an optimal algorithm of signal processing based on a compromise between the accuracy and speed of the systems as well as the labor intensity of calculations.

Recoupling pulse sequences with constant phase increments

The paper studies a family of recoupling pulse sequences in magic angle spinning (MAS) solid state NMR, that are characterized by constant phase increments at regular intervals. These pulse sequences can be employed for both homonuclear and heteronuclear recoupling experiments and are robust to dispersion in chemical shifts and rf-inhomogeneity. The homonuclear pulse sequence consists of a building block (2π)ϕp, where ϕp=p(n-1)πn, where n is number of blocks in a rotor period and p=0,1,2,…. The pulse sequence repeats itself every rotor period when n is odd and every two rotor period when n is even. The heteronuclear recoupling pulse sequence consists of a building block (2π)ϕ1p and (2π)ϕ2p on channel I and S, where ϕ1p=p(2n-3)π2n,ϕ2p=p(2n-1)π2n and n is number of blocks in a rotor period. The recoupling pulse sequences mix the z magnetization. Experimental quantification of this method is shown for 13Cα-13CO, homonuclear recoupling in a sample of Glycine and 15N-13Cα, heteronuclear recoupling in Alanine. Application of this method is demonstrated on a sample of tripeptide N-formyl-[U-13C,15N]- Met-Leu-Phe-OH (MLF).

Unwrapped wavefront evaluation in phase-shifting interferometry based on 3D dynamic fringe processing in state space.

Recovery of an unwrapped wavefront in phase-shifting interferometry is considered when the wavefront phase increments are determined between previous and subsequent fringe patterns as well as between adjacent pixels of the current fringe pattern. A parametric model of a three-dimensional interferometric signal and the recurrence processing algorithm in state space are utilized, providing an evaluation of an unwrapped wavefront phase at each phase shift step in dynamic mode. Estimates of the achievable accuracy and experimental results of the wavefront recovery are presented. Comparison with the conventional seven-frame phase-shifting algorithm, which is one of the most accurate, confirmed the high accuracy and noise immunity of the proposed method.

Abstract 2104: ERK-dependent IL-6 autocrine signaling mediates adaptive resistance to pan-PI3K inhibitor in head and neck squamous cell carcinoma

Abstract Purpose: To investigate resistant mechanisms to NVP-BKM120, a pan-PI3K inhibitor, and potential combination therapies in head and neck squamous cell carcinoma (HNSCC). Experimental Design: A panel of 10 human HNSCC cell lines including NVP-BKM120-resistant HNSCC patient-derived cell lines were used to evaluate the antitumor activity of NVP-BKM120. Patient-derived tumor xenograft (PDTX) models were established from recurrent/metastatic HNSCC patients treated with and resistant to NVP-BKM120. Results: Treatment of NVP-BKM120 led to upregulation of interleukin 6 (IL-6) and subsequent activation of either extracellular signal-regulated kinase (ERK) or signal transducers and activators of transcription 3 (STAT3), resulting in a modest antitumor effects on HNSCC cells. In a subset of cell lines, blockade of IL-6 autocrine signaling with IL-6 receptor (IL-6R) siRNA or IL-6R neutralizing antibody completely abolished constitutive or NVP-BKM120-induced activation of ERK and STAT3 as well as expression of oncogenic factors including Bcl2 and cMYC, resulting in the enhanced sensitivity to NVP-BKM120 with a marked reduction of S phase and significant increment of G0/G1 arrest. Interestingly, trametinib, a MEK inhibitor, significantly reduced NVP-BKM120-induced IL-6 and cMYC upregulation, whereas it had no effect on STAT3 inhibition. Moreover, combination of NVP-BKM120 with trametinib yielded more potent anti-tumor effects than combination with a pharmacologic inhibitor of STAT3 or siSTAT3. Furthermore, combination of NVP-BKM120 with trametinib or tocilizumab, a humanised anti-IL-6 receptor antibody, synergistically suppressed the growth of NVP-BKM120-resistant PDTX models as compared with either agent alone, which was confirmed in two PDTX-derived cell lines. Conclusions: Collectively, these results suggested that IL-6/ERK signaling contributes to intrinsic and adaptive resistance to NVP-BKM120 in HNSCC, providing a rationale for a novel therapeutic strategy to overcome resistance to pan-PI3K inhibitors. Citation Format: Mi Ran Yun, Han Na Kang, Byoung Chul Cho. ERK-dependent IL-6 autocrine signaling mediates adaptive resistance to pan-PI3K inhibitor in head and neck squamous cell carcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2104.

Filling of electronic density of states in Y-123 superconducting ceramics by nano Nd substitution on Ba site in crystal structure

This comprehensive examination focuses on the effect of the Nd substitution on the phase formation, mechanical, microstructural and superconducting properties of YBa2Cu3O7−x ceramics with the aid of standard experimental measurement tecniques as regards X-ray diffraction (XRD), dc resistivity (ρ-T), Vickers's microhardness (Hv) and scanning electron microscopy (SEM) measurements. For the full characterization of the pure and Nd substituted Y-123 samples, the onset–offset critical transition temperature, variation of transition temperature, crystal structure, grain size, phase purity and lattice parameters are determined and discussed clearly. The results demonstrate that the crucial characteristics given above improve with the increase in the Nd concentration level at the Ba-site in the superconducting core up until a critical value of x = 0.250 after which the characteristics tend to retrograde rapidly due to the transition of optimally doped state to the underdoped state position in the Y-123 superconducting lattice. This is in association with both the hole localization problem of the electronic states in the vicinity of the Fermi level and the presence of more disordered metallic state. The long and short of it is that the excess (0.250 < x) replacement of Ba inclusions for Nd impurities in the system leads to degradation of the major (Y-123) phase or increment of the minor phase (Y-211) in their intrinsic crystal structures with the phase transition from orthorhombic to pseudotetragonal in the crystal structure, being one of the most striking points deduced from this work. At the same time, the mechanical performance shows the similar trend (firstly increase then decrease) with the increase of the Nd inclusions inserted in the Y-123 superconducting matrix. The Vickers microhardness measurement evidences also declare that the plastic deformation is superior to the elastic deformation (no elastic recovery) in the samples presenting RISE behavior.

No clear evidence for localized tidal periodicities in earthquakes in the central Japan region

AbstractWe search for possible localized tidal triggering in earthquake occurrence near Japan by testing for tidal periodicities in seismicity within a variety of space/time bins. We examine 74,610 earthquakes of M ≥ 3 in the Japan Meteorological Agency catalog from January 2000 to April 2013. Because we use many earthquakes for which accurate focal mechanisms are not available, we do not compute tidal stresses on individual fault planes but instead assume that the mechanisms are likely to be similar enough among nearby events that tidal triggering will promote earthquake occurrence at specific tidal phases. After dividing the data into cells at a range of spatial (0.2°, 0.5°, and 1.0°) and temporal dimensions (100, 200, and 400 days), we apply Schuster's test for nonrandom event occurrence with respect to both the semidiurnal and semimonthly tidal phases. Because the resulting p values will be biased by temporal clustering caused by aftershocks, we apply a declustering method that retains only one event per tidal cycle per phase increment. Our results show a wide range of p values for the localized earthquake bins, but the number of bins with very small p values (e.g., p &lt; 0.05) is no more than might be expected due to random chance, and there is no correlation of low p value bins with the time of the 2010 M 9.0 Tohoku‐Oki earthquake.

Al2O3–ZrO2 nanostructured coatings using DC plasma electrolytic oxidation to improve tribological properties of Al substrates

Alumina–zirconia nanostructured coatings were formed on 7075 Al alloy through Plasma Electrolytic Oxidation (PEO) operated in aDC potentiostatic mode. The composite coatings were produced in the range of 425–500V in an alkaline electrolyte containing 4g/LK2ZrF6. Tribological properties of coatings were investigated using dry sliding wear test against WC balls with a pin-on-disc tribometer. Wear rates were evaluated using optical profilometer. It was shown that the nanostructured alumina–zirconia composite coatings can be formed at voltages ≥450V. The coating thickness and roughness were in the range of 15.2–24.2μm and 0.68–2.35μm, respectively. The distribution of Al, Zr and O in the coatings was uniform. Increasing the PEO voltage led to porosity increment and formation of the high temperature tetragonal zirconia phase (t-ZrO2). Significant enhancement in tribological properties for coated samples was achieved: under optimum conditions, corresponding to the PEO treatment at 500V for 200s, the coating wear rate of 2.62×10−6mm3N−1m−1 and friction coefficient of 0.22 were recorded that are about 120 and 3 times lower than those for the substrate.

Analysis of mcDESPOT‐ and CPMG‐derived parameter estimates for two‐component nonexchanging systems

To compare the reliability and stability of the multicomponent-driven equilibrium single pulse observation of T1 and T2 (mcDESPOT) and Carl-Purcell-Meiboom-Gill (CPMG) approaches to parameter estimation. The stability and reliability of mcDESPOT and CPMG-derived parameter estimates were compared through examination of energy surfaces, evaluation of model sloppiness, and Monte Carlo simulations. Comparisons were performed on an equal time basis and assuming a two-component system. Parameter estimation bias, reflecting accuracy, and dispersion, reflecting precision, were derived for a range of signal-to-noise ratios (SNRs) and relaxation parameters. The energy surfaces for parameters incorporated into the mcDESPOT signal model exhibit flatness, a complex structure of local minima, and instability to noise to a much greater extent than the corresponding surfaces for CPMG. Although both mcDESPOT and CPMG performed well at high SNR, the CPMG approach yielded parameter estimates of considerably greater accuracy and precision at lower SNR. mcDESPOT and CPMG both permit high-quality parameter estimates under SNR that are clinically achievable under many circumstances, depending upon available hardware and resolution and acquisition time constraints. At moderate to high SNR, the mcDESPOT approach incorporating two-step phase increments can yield accurate parameter estimates while providing values for longitudinal relaxation times that are not available through CPMG. However, at low SNR, the CPMG approach is more stable and provides superior parameter estimates. Magn Reson Med 75:2406-2420, 2016. © 2015 Wiley Periodicals, Inc.

Are ta-siRNAs only originated from the cleavage site of miRNA on its target RNAs and phased in 21-nt increments?

Trans-acting siRNAs (ta-siRNAs) are a class of small RNAs playing crucial roles in the regulation of plant gene expression. According to the canonical model, specific miRNA-guided cleavage of a TAS transcript triggers and sets the registry for the subsequent production of ta-siRNAs at 21-nt increments from the cleavage site. However, a previously validated 22-nt ta-siR2140 indicated that ta-siRNAs might be initiated from other phase increments and registers, which resulted in massive ta-siRNAs missing in the canonical model. To test this hypothesis, we employed high-throughput sequencing data to thoroughly identify the miR173-triggered ta-siRNAs from TAS1/TAS2 transcripts. As a result, thousands of phased siRNAs not generated through the canonical pathway were identified and 110 novel siRNA—target interactions were further validated based on degradome sequencing data. Based on these results, we propose that the canonical biogenesis model of ta-siRNAs should be modified in order to recruit the previously unidentified ta-siRNA candidates.

Discrete emitters as a source of orbital angular momentum

Generation of light carrying orbital angular momentum (OAM) is of fundamental interest due to its applications in a broad range of fields, such as classical and quantum optical communications, and optical micro-manipulation. Light carrying a well defined state of OAM is typically created by imparting an azimuthally varying phase structure onto a plane wave. In this work, we investigate, using numerical simulations and experiments, the OAM spectra of light radiated from a heavily course grained emission pattern: an array of discrete circular apertures arranged in a ring configuration, with a constant phase increment between adjacent apertures. We show how the number of apertures and their relative phase defines the position and spacing of peaks in the OAM spectra. We demonstrate that by spatially filtering beams emitted from such a configuration, higher order peaks in the OAM spectra can be suppressed, leaving a single dominant lowest order peak, and recovering a beam carrying a well-defined OAM state. We qualitatively interpret the efficiency of generating beams this way in terms of the angular uncertainty principle.

Firefly-Inspired Synchronicity with a Weighted Factor for Wireless Sensor Networks

Firefly-inspired synchronicity method using reackback response is effective with existence of message delay. We introduce a weighted factor based on RSSI into the phase increment calculation. Besides, different coupling strength parameters are selected according to the degree of synchronicity to achieve a good balance between synchronicity speed and accuracy. Simulink module is constructed and the results prove that this method shows great resistance against random variation of the message delay within an acceptable range.

Parallel Monitoring of Living Cell Cultures by Means of Digital-Holography and Fluorescent Microscopy

We propose using the method of holographic microscopy to detect fine morphologic changes in living cells. An “LSM 510” laser confocal scanning microscope is modified to allow recording digital microholograms which can be used to reconstruct the amplitude and phase of the radiation transmitting through the sample. Measuring the phase increment of the object beam in cells and the intercellular space yields information on the optical length of the ray path in the cells (spatial dimensions and the refractive index), which in turn contains information on changes in the morphology and intracellular contents. Calcium activity is studied by means of fluorescent microscopy which makes it possible to detect minor variations in the intracellular concentration of calcium ions. By studying the dynamics of calcium oscillations and variations in the optical thickness, conclusions are made about the interrelation of functional and morphological variations, and comparative analysis of these variations is performed.

Analysis of HY2A precise orbit determination using DORIS

HY2A is the first Chinese marine dynamic environment satellite. The payloads include a radar altimeter to measure the sea surface height in combination with a high precision orbit to be determined from tracking data. Onboard satellite tracking includes GPS, SLR, and the DORIS DGXX receiver which delivers phase and pseudo-range measurements. CNES releases raw phase and pseudo-range measurements with RINEX DORIS 3.0 format and pre-processed Doppler range-rate with DORIS 2.2 data format. However, the VMSI software package developed by Van Martin Systems, Inc which is used to estimate HY2A DORIS orbits can only process Doppler range-rate but not the DORIS phase data which are available with much shorter latency. We have proposed a method of constructing the phase increment data, which are similar to range-rate data, from RINEX DORIS 3.0 phase data. We compute the HY2A orbits from June, 2013 to August, 2013 using the POD strategy described in this paper based on DORIS 2.2 range-rate data and our reconstructed phase increment data. The estimated orbits are evaluated by comparing with the CNES precise orbits and SLR residuals. Our DORIS-only orbits agree with the precise GPS+SLR+DORIS CNES orbits radially at 1-cm and about 3-cm in the other two directions. SLR test with the 50° cutoff elevation shows that the CNES orbit can achieve about 1.1-cm accuracy in radial direction and our DORIS-only POD solutions are slightly worse.In addition, other HY2A DORIS POD concerns are discussed in this paper. Firstly, we discuss the frequency offset values provided with the RINEX data and find that orbit accuracy for the case when the frequency offset is applied is worse than when it is not applied. Secondly, HY2A DORIS antenna z-offsets are estimated using two kinds of measurements from June, 2013 to August, 2013. The results show that the measurement errors contribute a total of about 2-cm difference of estimated z-offset. Finally, we estimate HY2A orbits selecting 3days with severe geomagnetic storm activity and SLR residuals suggest that estimating a drag coefficient every 6h without any constraint is sufficient for maintaining orbit accuracy.

Effects of gadolinium and silicon substitution on magnetic properties and microstructure of Nd–Fe–B–Nb bulk nanocomposite magnets

Abstract The magnetic properties, phase evolution and microstructure of Fe70−xMxB19Nd7Nb4 (M=Si, Gd, Si+Gd; x=0–2.5 at%) bulk nanocomposite permanent magnets in the form of rods produced by annealing the amorphous precursor have been investigated systematically. Microstructural examination, three-dimensional atom probe microanalysis, δM-plots, X-ray diffraction analysis and magnetometer studies deduced that good magnetic properties in the magnets originate from the homogenous microstructure consisting of exchange coupled, soft magnetic (α-Fe, Fe3B) and hard magnetic (Nd,Gd)2Fe14B nanophases. Optimally annealed Fe70B19Nd7Nb4 rod magnets exhibit magnetic properties of Br=0.61 T, iHc=876 kA/m and (BH)max=50.2 kJ/m3. Gadolinium and silicon addition to quaternary Fe70B19Nd7Nb4 alloy increased the mass fraction of hard magnetic phase, strengthened the exchange coupling interactions and enhanced the magnetic properties. Gadolinium and silicon segregated into hard magnetic phase which led to enhance coercivity up to 1115 kA/m. Enhancement in the coercivity is mainly resulted by hard phase increment as well as domain wall pinning, while strengthening of exchange coupling is caused by grain size refinement and increase in Curie temperature of the magnetic phases. The Fe67B19Nd7Gd2Nb4Si1 magnetic rods of 1.2 mm in diameter demonstrated the best magnetic properties such as intrinsic coercivity, iHc of 1115 kA/m, remanence, Br of 0.57 T and maximum energy product, (BH)max of 65.7 kJ/m3.

Null Forming in Circularly Polarized Antenna Patterns Using Reactive Loading of Multi-Arm Archimedean Spiral Antenna

A multi-arm spiral antenna, of N arms, can have N modes of operation. The integer n represents the operating mode which is determined by the signal phase increment between adjacent arms as fed from the antenna terminals. For the antenna to radiate effectively, the active region must be enclosed by a circumference of mode number (n) times the operating wavelength. Each mode generates a different radiation pattern. Modes, with n between 2 and N-2, are capable of forming radiation pattern nulls. This paper shows a way to excite noninteger modes along with integer modes of radiation, which combined, can create a null which can be steered away from the antenna vertical bore sight. Furthermore, variable reactive loading of spiral arm ends offers additional steering control and positioning of nulls in a 2D angular hemispherical space.

Metaplectic sheets and caustic traversals in the Weyl representation

The quantum Hamiltonian generates in time a family of evolution operators. Continuity of this family holds within any choice of representation and, in particular, for the Weyl propagator, even though its simplest semiclassical approximation may develop caustic singularities. The phase jumps of the Weyl propagator across caustics have not been previously determined. The semiclassical approximation relies on individual classical trajectories together with their neighbouring tangent map. Based on the latter, one defines a continuous family of unitary tangent propagators, with an exact Weyl representation that is close to the full semiclassical approximation in an appropriate neighbourhood. The phase increment of the semiclassical Weyl propagator, as a caustic is crossed, is derived from the facts that the corresponding family of tangent operators belong to the metaplectic group and that the products of the tangent propagators are obtained from Gaussian integrals. The Weyl representation of the metaplectic group is presented here, with the correct phases determined within an intrinsic ambiguity for the overall sign. The elements that fully determine the phase increment across a particular caustic are then analysed.

Dual regulation of mast cell degranulation through IgE receptor-mediated modulation of M2-type pyruvate kinase

It was reported that mast cell degranulation is inversely related to the enzymatic activity of M₂-type pyruvate kinase (M₂PK). This study shows that activation of high-affinity IgE receptor (FcεRI) evokes a sequential dual regulation of M₂PK, i.e., an immediate decrement followed by slow phase increment of enzymatic activities. Changes in the activities of M₂PK and mast cell degranulation showed similar time course after antigenic stimulation of FcεRI. The immediate inhibition of M₂PK involved tyrosine phosphorylation, and subsequently led to a cellular accumulation of glycolytic intermediates, including fructose 1,6-biphosphate (FBP), a feedforward activator of M₂PK. As the cellular levels of FBP were increased, both the enzymatic acitivity of M₂PK and mast cell degranulation slowly returned to near basal levels. A-Raf, when exogenously introduced into RBL-2H3 cells, phosphorylated M₂PK on the serine residues, elevated enzyme activities of M₂PK, and resulted in the inhibition of degranulation. These results suggest that dual regulation of M₂PK which involves the phosphorylation of M₂PK and accumulation of a feedforward activator of M₂PK plays important roles in the control of mast cell degranulation.

Design of Modulation and Packet Detection in Body Area Networks

In burst communication systems like Body Area Networks (BAN), burst packet should be detected prior to the demodulation of the signal at the receiver. Meanwhile, different modulation and demodulation algorithms may affect the BER performance of the entire system seriously. To satisfy the conditions that BAN nodes or devices have to be small in size and very low in power consumption, algorithm design of modulation and packet detection are very important. Referring to IEEE 802.15.6 BAN standard, theoretical analysis of the modulation and demodulation for π/2-DBPSK and π/4-DQPSK is carried out first. The two modulations are realized by using two different two-step looking up table respectively and then united to be one by combining the two phase increment tables. By use of the special structure of π/2-DBPSK modulated preamble, packet detection algorithm with low complexity is also carefully designed. Simulation results of BER performance are presented at last. In AWGN channel, both modulations achieve good performance, and performance degradation of π/4-DQPSK happens in multipath channel which may not satisfy the requirements. Adaptive modulation is considered to solve this problem by choosing different modulation scheme according to channel quality.

하프 빈야사 요가 수련 전·후의 역학적 에너지 변화 - 신체분절의 에너지 기여도 및 최고무게중심과 분절 에너지의 상관관계를 중심으로 -

The purpose of this study was to investigate change of mechanical energy before and after training of half vinyasa yoga. Thirteen subjects (height: <TEX>$163.4{\pm}3.9$</TEX> cm, body mass: <TEX>$54.9{\pm}7.3$</TEX> kg, age: <TEX>$20.0{\pm}0.49$</TEX> yrs) participated in this experiment. The motions of half vnyasa yoga were captured with Vicon system and parameters were calculated with Visual-3D. After training of half vinyasa yoga, the mechanical energies of body segments were increased and increments of mechanical energies in the lower segments were greater than the upper segments. The phase increments of mechanical energies increased phase 1, phase 2, and phase 3 in order. After training of half vinyasa yoga, phase contributions of body segments were similar before training of half vinyasa yoga. The contribution of mechanical energy on trunk segment in body was the greatest contribution of upper segments; also that of mechanical energy on thigh segment in body was the greatest contribution of lower segments. Before training, the coefficient of correlation between vertical center of gravity (CoGz) and mechanical energy of phase 3 was a -.559, but after training, the coefficient of correlation between CoGz and mechanical energy of phase 2 was a .587. These findings suggest that the training of half vinyasa yoga may be increasing the mechanical energies of body segments.