用于原子干涉仪的拉曼光的制备

原子干涉仪是利用原子物质波的特性而实现的干涉仪,广泛应用于精密测量领域.在原子干涉仪中,通过拉曼光对原子进行相干操作,拉曼光的质量直接影响着干涉仪的技术指标.基于注入锁定技术,采用普通半导体激光器、声光调制器,实现了功率、频率和位相稳定的拉曼光的制备,并对拉曼光的相位噪声技术指标进行了测试.     

Phase-only hologram generation based on integral imaging and its enhancement in depth resolution

We introduce a phase-only hologram generation method based on an integral imaging,and propose an enhancement method in representable depth interval.The computational integral imaging reconstruction method is modified based on optical flow to obtain depth-slice images for the focused objects only.A phaseonly hologram for multiple plane images is generated using the iterative Fresnel transform algorithm.In addition,a division method in hologram plane is proposed for enhancement in the representable minimum depth interval.     

Paradoxical high signal intensity of hepatocellular carcinoma in the hepatobiliary phase of Gd-EOB-DTPA enhanced MRI: initial experience

Purpose

To describe the paradoxical high signal intensity of hepatocellular carcinoma (HCC) in the hepatobiliary phase on gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI).

Materials and Methods

A database search was performed to identify cases of HCC that showed unusual prolonged enhancement in the hepatobiliary phase of Gd-EOB-DTPA MRI. All patients received 3.0-T liver MRI including precontrast T1-weighted images, T2-weighted images and a post Gd-EOB-DTPA-enhanced dynamic study. The signal intensity of HCC was measured at pre-enhanced, arterial, portal, delayed and hepatobiliary phase using regions of interest. Radiologic and pathologic correlation was performed for the paradoxically prolonged enhancing portion of HCC in the hepatobiliary phase.

Results

Four patients (all male, age range 44-70; mean 57.5 years) were included in this study. All patients showed HCC lesions that were low signal intensity (SI) on T1-WI, high SI on T2-WI, enhanced in arterial phase, and washed-out in delayed phase. All cases showed paradoxically high SI in hepatobiliary phase, which was unusual for HCC. Pathologically, they were all diagnosed as well-differentiated HCC with prominent cytoplasm and a bile secreting appearance.

Conclusion

HCC may demonstrate the prolonged high signal intensity at the hepatobiliary phase on Gd-EOB-DTPA enhanced MRI. These HCCs tended to be highly differentiated and to have prominent bile secretion.     

Photonic temporal integration of broadband intensity waveforms over long operation time windows

We propose and experimentally demonstrate a novel design for temporal integration of microwave and optical intensity waveforms with combined high processing speed and a long operation time window. It is based on concatenating in series a discrete-time (low-speed) photonic integrator and a high-speed analog time-limited intensity integrator. This scheme is demonstrated here using a cascaded fiber-based interferometers' system (as a passive eight-point discrete-time integrator) and an analog time-limited intensity integrator. The latter is based on temporal intensity modulation of the input waveform with a rectangular-like incoherent energy spectrum followed by linear dispersion. Using this setup, we experimentally achieve accurate time integration of intensity signals with ~36 GHz bandwidths over an operation time window of ~4 ns, corresponding to a processing time-bandwidth product of >144.     

Observation of transverse polarization asymmetries of charged pion pairs in e+e- annihilation near √s = 10.58 GeV

The interference fragmentation function translates the fragmentation of a quark with a transverse projection of the spin into an azimuthal asymmetry of two final-state hadrons. In e(+)e(-) annihilation the product of two interference fragmentation functions is measured. We report nonzero asymmetries for pairs of charge-ordered π(+)π(-) pairs, which indicate a significant interference fragmentation function in this channel. The results are obtained from a 672 fb(-1) data sample that contains 711 × 10(6) π(+)π(-) pairs and was collected at and near the Υ(4S) resonance, with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider.     

Single spin asymmetries in charged pion production from semi-inclusive deep inelastic scattering on a transversely polarized 3He Target at Q2 = 1.4-2.7 GeV2

We report the first measurement of target single spin asymmetries in the semi-inclusive (3)He(e,e'π(±))X reaction on a transversely polarized target. The experiment, conducted at Jefferson Lab using a 5.9 GeV electron beam, covers a range of 0.16 < x < 0.35 with 1.4 < Q(2) < 2.7 GeV(2). The Collins and Sivers moments were extracted from the azimuthal angular dependence of the measured asymmetries. The π(±) Collins moments for (3)He are consistent with zero, except for the π(+) moment at x = 0.35, which deviates from zero by 2.3σ. While the π(-) Sivers moments are consistent with zero, the π(+) Sivers moments favor negative values. The neutron results were extracted using the nucleon effective polarization and measured cross section ratios of proton to (3)He, and are largely consistent with the predictions of phenomenological fits and quark model calculations.     

Suppression of samarium diffusion in top seeded melt growth processed Y123 superconductors using a Sm123 seed

To suppress the samarium diffusion from a SmBa₂Cu₃O_7?y (Sm123) seed into an YBa₂Cu₃O_7?y (Y123) compact during a top seeded melt growth (TSMG) process, Y211 buffer disks of various thicknesses (t) were inserted at the seed/compact interface. The effectiveness of the Y211 buffer insert on the suppression of samarium diffusion was estimated from the susceptibility curve and composition analysis for the three top surface regions (region just below the seed/buffer, intermediate region between the buffer and compact edge and compact edge). The difference in the superconducting temperature (T_c) and the superconducting transition width (ΔT) in the three regions was large, when no buffer or thin buffers (t is smaller than 1 mm) were used. As a buffer disk of an appropriate thickness was inserted into the seed/compact interface, the difference in T_c and ΔT in the three regions was much reduced. The composition analysis across the seed/buffer/compact region clearly revealed that the T_c decrease was caused by the samarium diffusion from a seed, which led to the formation of Y_1?xSm_xBa₂Cu₃O_7?y in the Y123 compact region. The buffer insert technique was demonstrated to insure the uniform superconducting properties of the top surface of TSMG processed Y123 superconductors.     

Effects of calcium doping on the superconducting properties of top-seeded melt growth processed Y1.5Ba2−xCaxCu3Oy superconductors

The effect of calcium doping on the superconducting properties of top seeded melt growth (TSMG) processed Y_1.5Ba_2?xCa_xCu₃O_y superconductors was studied in terms of calcium content (X_ca). YBa_2?xCa_xCu₃O_7?δ (X_ca = 0, 0.005, 0.01, 0.02, 0.04, 0.1, 0.3) powders were synthesized by the powder calcination method. YBa_2?xCa_xCu₃O_7?δ powders were mixed with 0.25 mole Y₂O₃ powder and 1 wt.% CeO₂ as Y₂BaCuO₅ (Y211) refiner, and finally made into Y₁.₅Ba_2?xCa_xCu₃O_y (Y1.5) + 1 wt.% CeO₂ composition. The single Y123 growth on the top surface was observed up to X_ca = 0.1, while the multiple Y123 growth was observed at X_ca ? 0.1. The superconducting transition temperature (T_c) and critical current density (J_c) of TSMG processed Y1.5 samples were inversely proportional to X_ca. The Y211 size increased with increasing X_ca due to the enhancement of Y211 coarsening by calcium doping. No Y211 refining effect by CeO₂ was observed in the calcium doped samples. The T_c and J_c decrease by calcium doping are likely to be due to the calcium incorporation with the Y123 lattice and formation of coarse Y211 particles.     

Analytic soliton solutions of cubic‐quintic Ginzburg‐Landau equation with variable nonlinearity and spectral filtering in fiber lasers

In fiber lasers, the study of the cubic‐quintic complex Ginzburg‐Landau equations (CGLE) has attracted much attention. In this paper, four families (kink solitons, gray solitons, Y‐type solitons and combined solitons) of exact soliton solutions for the variable‐coefficient cubic‐quintic CGLE are obtained via the modified Hirota method. Appropriate parameters are chosen to investigate the properties of solitons. The influences of nonlinearity and spectral filtering effect are discussed in these obtained exact soliton solutions, respectively. Methods to amplify the amplitude and compress the width of solitons are put forward. Numerical simulation with split‐step Fourier method and fourth‐order Runge‐Kutta algorithm are carried out to validate some of the analytic results. Transformation from the variable‐coefficient cubic‐quintic CGLE to the constant coefficients one is proposed. The results obtained may have certain applications in soliton control in fiber lasers, and may have guiding value in experiments in the future.