Quantifying quantum correlation via quantum coherence

Resource theory is applied to quantify the quantum correlation of a bipartite state and a computable measure is proposed. Since this measure is based on quantum coherence, we present another possible physical meaning for quantum correlation, i.e., the minimum quantum coherence achieved under local unitary transformations. This measure satisfies the basic requirements for quantifying quantum correlation and coincides with concurrence for pure states. Since no optimization is involved in the final definition, this measure is easy to compute irrespective of the Hilbert space dimension of the bipartite state.     

考虑信号灯影响的交通流模型与数值模拟

基于信号灯交通系统中跟车行为的特点,改进了现有跟车方程,提出一个考虑信号影响的交通流模型.数值计算结果表明,该模型可以很好地再现车流的聚集与消散、停车波和启动波的演化规律及传播特性,证明模型是合理有效的. 关键词： 交通流模型 信号灯 停车波 启动波     

LD-end-pumped Nd:YAP laser operating at 1341.4 nm and doubling of its frequency

We report an LD-end-pumped linearly-polarized continuous-wave (CW) Nd:YAP laser operating at 1341.4 nm. Making use of the plane-concave resonator (T = 2.4%) and the plane-plane resonator (T = 2.6%), we obtain linearly-polarized laser radiation at 1341.4 nm with a power of 3.15 and 2.86 W and corresponding optical slope efficiency of 18.4 and 17.5%, respectively. The effect of the laser oscillation mode on the output is analyzed. An experiment on the intra-cavity frequency doubling with an LBO crystal has been performed, and a laser power of 431 mW in one direction at 670.7 nm was obtained.     

SPR and SERS characteristics of gold nanoaggregates with different morphologies

In this study, surface plasmon resonance (SPR) and surface-enhanced Raman scattering (SERS) characteristics of gold nanoaggregates with different morphologies are examined to elucidate the correlation between SPR and SERS of the object. Nanoaggregates, defined as random aggregates (hereafter RA), elongated aggregates (hereafter EA) and two-dimensional layered aggregates (hereafter 2DLA) are fabricated by immobilizing colloidal gold nanoparticles on glass substrates. The color variation observed in the RA and EA samples indicates the variation in localized SPR excitations excited on the samples. The RA sample mostly shows a broadened and shifted SPR peak centered at 570 nm in addition to another peak in the longer wavelength region (∼700 nm), whereas in the EA sample a weak blue-shifted peak is observed near 450 nm in addition to a broadened peak centered at 570 nm covering a trail for another one near 700 nm. In the case of the 2DLA sample, more than one SPR peaks are observed in the longer wavelength region. The SERS observation confirms million times higher enhancement at least in Raman intensity using the gold nanoaggregates adsorbed by dye molecules. The EA sample of gold nanoparticles shows ∼5 times higher enhancement in Raman signal compared to that of the RA and 2DLA sample.     

Secure Direct Communication Based on Non-Orthogonal Entangled Pairs and Local Measurement

We propose a quantum secure direct communication scheme based on non-orthogonal entangled pairs and local measurement. In this scheme, we use eight non-orthogonal entangled pairs to act as quantum channels. Due to the non-orthogonality of the quantum channels, the present protocol can availably prohibit from all kinds of valid eavesdropping and acquire a secure quantum channel. By local measurement, the sender acquires a secret random sequence. The process of encoding on the random sequence is identical to the one in one-time-pad. So the present protocol is secure. Even for a highly lossy channel, our scheme is also valid. The scheme is feasible with present-day techniques.     

Designing a coupler for the intersatellite optical communication system

Coupling a single-mode laser diode with 200 mW to a single-mode fiber (SMF) through an orthonormal aspherical cylindrical lens and a GRIN lens for the intersatellite optical communication system is proposed and demonstrated. We experimentally studied how the coupling efficiency changes with the SMF's position displacement and axial angle variation, and obtained 80 mW output power at the end of the SMF, which shows that the coupling units have satisfied the designed request.     

Immobilization of bovine serum albumin on TiO2 film via chemisorption of H3PO4 interface and effects on platelets adhesion

In the present study, bovine serum albumin (BSA) was successfully covalently immobilized on the surface of anatase TiO₂ film by a three-step method, i.e. application of H₃PO₄ chemisorption to increase surface -OH, which increases the amount of coupling 3-aminopropyl-triethoxylsilane (APTES), thus linking with BSA by imide bond using EDC/NHS/MES. There is no significant -OH group increase on rutile film when using the same method of phosphoric acid treatment, which suggest it is difficult for further chemical modification of the rutile film. After covalent immobilization of BSA on anatase film, an improved hemocompatibility of anti-platelet adhesion and aggregation in vitro could be recognized by LDH and SEM analysis. This study suggests BSA-immobilized anatase surface can serve as hemocompatibility material in vivo.     

Temperature and substrate dependence of structure and growth mechanism of carbon nanofiber

The carbon nanofibers were grown on Ni/Si and Ni/Ti/Si substrates in 1 atm CH₄ atmosphere at 640 °C and 700 °C by thermal chemical vapor deposition method. The carbon nanofibers were characterized by field emission scanning electron microscopy, transmission electron microscopy, and Raman spectrometry for morphology, microstructure, and crystallinity. The electron emission property of carbon nanofibers was also investigated by current-voltage (I-V) measurement. The results showed that the solid amorphous carbon nanofibers could be grown on Ni/Si substrate at 640 °C through tip growth mechanism, the carbon nanotubes could be grown on Ni/Si substrate at 700 °C through tip growth mechanism, and the carbon nanotubes could be grown on Ni/Ti/Si substrate at 700 °C through root growth mechanism.     

Up-regulation of Na expression in the area postrema of total sleep deprived rats by TOF-SIMS analysis

Area postrema (AP) is a circumventricular organ plays an important role in sodium homeostasis and cardiovascular regulation. Since sleep deficiency will cause cardiovascular dysfunction, the present study aims to determine whether sodium level would significantly alter in AP following total sleep deprivation (TSD). Sodium level was investigated in vivo by time-of-flight secondary ion mass spectrometry (TOF-SIMS). Clinical manifestation of cardiovascular function was demonstrated by mean arterial pressure (MAP) values. Results indicated that in normal rats, TOF-SIMS spectrum revealed a major peak of sodium ion counting as 5.61 × 10⁵ at m/z 23. The sodium ions were homogeneous distributed in AP without specific localization. However, following TSD, the sodium intensity was relatively increased (6.73 × 10⁵) and the signal for sodium image was strongly expressed throughout AP with definite spatial distribution. MAP of TSD rats is 138 ± 5 mmHg, which is significantly higher than that of normal ones (121 ± 3 mmHg). Regarding AP is an important area for sodium sensation and development of hypernatremic related sympatho-excitation; up-regulation of sodium expression following TSD suggests that high sodium level might over-activate AP, through complex neuronal networks involving in sympathetic regulation, which could lead to the formation of TSD relevant cardiovascular diseases.     

Vandermonde-like determinants’ representations of Darboux transformations and explicit solutions for the modified Kadomtsev-Petviashvili equation

Recently, the (2+1)-dimensional modified Kadomtsev-Petviashvili (mKP) equation was decomposed into two known (1+1)-dimensional soliton equations by Dai and Geng [H.H. Dai, X.G. Geng, J. Math. Phys. 41 (2000) 7501]. In the present paper, a systematic and simple method is proposed for constructing three kinds of explicit N-fold Darboux transformations and their Vandermonde-like determinants’ representations of the two known (1+1)-dimensional soliton equations based on their Lax pairs. As an application of the Darboux transformations, three explicit multi-soliton solutions of the two (1+1)-dimensional soliton equations are obtained; in particular six new explicit soliton solutions of the (2+1)-dimensional mKP equation are presented by using the decomposition. The explicit formulas of all the soliton solutions are also expressed by Vandermonde-like determinants which are remarkably compact and transparent.