Zeeman effects on d-wave superconductor and tunneling spectrum in normal-metal/d-wave superconductor tunnel junction

We study the Zeeman effect on the d-wave superconductor and tunneling spectrum in normal-metal(N)/d-wave superconductor(S) junction by applying a Zeeman magnetic field to the S. It is shown that: (1) the Zeeman magnetic field can lead to the S gap decreasing, and with the increase in Zeeman energy, the superconducting state is changed to the normal state, exhibiting a first-order phase transition; (2) the Zeeman magnetic field may make the zero-bias conductance peak split into two peaks, and the energy difference between the two splitting peaks in the conductance spectrum is equal to 2h ₀ (h ₀ is the Zeeman energy); (3) both the barrier strength of interface scattering and the temperature can lower the magnitudes of splitting peaks, of which the barrier strength can lead to the splitting peaks becoming sharp and the temperature can smear out the peaks, however, neither of them can influence the Zeeman effect.     

针孔辅助点投影诊断方法实验研究

针孔辅助点投影背光成像是近几年国外新兴的等离子体诊断技术,在惯性约束聚变相关物理实验诊断中具有重要的应用前景.为验证这一诊断方法的实用性,在神光Ⅱ第九路平台上开展了演示实验.利用激光驱动平面Ti靶获得约4.7 keV的Ti K壳层X射线,在十几微米的针孔约束下作为次级点源并对Au栅格样品投影成像,并用CCD记录.实验成功获得了清晰的样品二维空间分辨的时间积分图像,空间分辨力优于16.1 μm.实验结果表明针孔辅助点投影具有较高的空间分辨力、较大的视场、较高的图像对比度,将成为瑞利泰勒不稳定性研究、激光状态方程研究等物理实验的重要诊断方法之一.     

Temperature and injection current dependent electroluminescence study of GaInP/AlGaInP quantum well laser diode grown using tertiarybutylarsine and tertiarybutylphosphine

GaInP/AlGaInP triple quantum well (TQW) lasers, grown by metalorganic chemical vapor deposition (MOCVD) using tertiarybutylarsine (TBAs) and tertiarybutylphosphine (TBP), were fabricated with a pulsed anodic oxidation (PAO) process. The devices worked at room temperature (RT) with the lowest threshold current density (J_th) of 1.5 kA/cm² ever reported for GaInP/AlGaInP lasers grown using TBAs and TBP. Temperature dependent (35–250 K) electroluminescence (EL) study of the GaInP/AlGaInP laser diode showed almost the same luminescence quenching behavior at a high temperature region (120–250 K), independent of the injection current (100–150 mA). A model involving a nonradiative recombination mechanism was presented to interpret the EL quenching behavior over the experimental temperature range. The nonradiative recombination centers in the Al-containing barrier or cladding layer are believed to contribute to the loss of carriers via nonradiative recombination. PACS 78.60.Fi; 71.20.Nr; 78.67.De; 81.15.Gh; 42.55.Px     

High-j proton alignments in 101Pd

High-spin states in ¹⁰¹Pd have been investigated by means of in-beam γ-ray spectroscopic techniques via the ⁷⁶Ge(²⁸Si, 3n) reaction at beam energies of 85 and 95 MeV. The previously known d _5/2 and 1/2^?[550] bands were extended to higher spins, and the unfavored signature branch of the 1/2^?[550] band was built. The band crossings observed experimentally are explained by the alignment of g _9/2 protons. The band properties in ¹⁰¹Pd are compared with those in the neighboring nuclei and are discussed within the framework of the cranked shell model (CSM).     

Diagnostic value of nonlinear optical signals from collagen matrix in the detection of epithelial precancer

During precancer development in epithelium, neoplastic cells remodel the underlying stroma, for example, the basement membrane, capillaries, fibroblasts, and extracellular matrix. The purpose of this study is to investigate the relationship between the nonlinear optical signals from the collagen matrix in stroma and the progression of early epithelial carcinogenesis. Two-photon excited fluorescence (TPEF) and second harmonic generation (SHG) signals were measured from the stroma of hamster oral cheek pouch in vivo. We found that three features, including the intensity ratio of TPEF over SHG, the spatial frequency distribution, and the texture feature of SHG images, provide the quantitative identification of epithelial precancer at different pathologic stages. We demonstrated that the combination of all three features by using a support vector machine algorithm can significantly improve the accuracy in the detection of epithelial precancer.     

Surface modification of pure titanium by pulsed electron beam

The microstructure, hardness and corrosion resistance of commercially pure Ti treated by low energy high current pulsed electron beam (LEHCPEB) have been investigated. The thin near-surface melted layer rapidly solidified into β and subsequently transformed into ultrafine α′ martensite. This has led to a drastic improvement of the corrosion properties and a significant increase (more than 60%) in hardness of the top surface.     

On the rank-dependence of coal tar secondary reactions

The secondary reactions of volatile compounds, including coal tar and light gases, accounts for a great portion of soot formation and the subsequent heat release and pollutant emissions in the combustion zone. While coal primary pyrolysis has been extensively studied over the last few decades and several network pyrolysis models has been developed to describe this process, coal secondary pyrolysis is still not well understood. The Babcock and Wilcox Company has been investigating coal secondary pyrolysis in order to develop a comprehensive mechanism for inclusion in predictive computational fluid dynamics and coal combustion models. Supportive experiments were carried out in an entrained-flow reactor. Tar was extracted from the pyrolysis byproducts of seven coals of widely-distributed rank at temperatures ranging from 923 to 1473 K, and analyzed by ¹³C NMR. Tars formed from higher rank coals generally demonstrated higher sooting propensities. This rank-dependent sooting propensity is associated with tar’s chemical structure properties. With increased heat treatment severity, tar molecules lose a substantial amount of aliphatic attachments, and the average size of substitution per cluster decreases. Compared to tars formed from high-rank bituminous coals, those formed from low-rank sub-bituminous coals have a larger attachment portion, higher averaged substitution, and higher oxygen-containing functional groups. These differences contribute to the higher cracking propensity observed for low-rank coal tars.     

A piecewise local regularized Richardson-Lucy algorithm for remote sensing image deconvolution

As it is not possible to obtain an accurate point spread function (PSF) in remote sensing imaging, classic deconvolution methods such as Wiener filtering often introduce strong noise and ringing artifacts, which contaminate the restored images. In this paper, we modify the standard Richarson-Lucy (RL) algorithm with a piecewise local regularization term and combine it with residual deconvolution method. Experimental results show that it is effective in suppressing negative effects, and images with rich details and sharp edges are obtained.     

Simultaneous measurement of strain and temperature with a long-period fiber grating inscribed Sagnac interferometer

A Sagnac interferometer with a long-period fiber grating (LPG) inscribed in the polarization-maintaining fiber (PMF) is proposed and experimentally demonstrated for simultaneous measurement of strain and temperature. Due to the different responses of the LPG and the Sagnac interferometer to strain and temperature, simultaneous measurement can be achieved by monitoring the wavelength shifts and the intensity changes of a resonance dip of the sensor setup. The experimental results show that the achieved sensitivities to strain and temperature are 6.4 × 10^− 3 dB/με and 0.65 nm/°C, respectively.     

Experimental long-distance decoy-state quantum key distribution based on polarization encoding

We demonstrate the decoy-state quantum key distribution (QKD) with one-way quantum communication in polarization space over 102 km. Further, we simplify the experimental setup and use only one detector to implement the one-way decoy-state QKD over 75 km, with the advantage to overcome the security loopholes due to the efficiency mismatch of detectors. Our experimental implementation can really offer the unconditionally secure final keys. We use 3 different intensities of 0, 0.2, and 0.6 for the light sources in our experiment. In order to eliminate the influences of polarization mode dispersion in the long-distance single-mode optical fiber, an automatic polarization compensation system is utilized to implement the active compensation.