Broadly Tunable Grating-Coupled External Cavity Laser With Quantum-Dot Active Region

A broadly tunable and high-power grating-coupled external cavity laser with a tuning range of more than 200 nm and a similar to 200-mW maximum output power was realized, by utilizing a gain device with the chirped multiple quantum-dot (QD) active layers and bent waveguide structure. The chirped QD active medium, which consists of QD layers with InGaAs strain-reducing layers different in thickness, is beneficial to the broadening of the material gain spectrum. The bent waveguide structure and facet antireflection coating are both effective for the suppression of inner-cavity lasing under large injection current.

崔—Lawson模型与logistic方程的比较研究

本文对崔—Lawson模型与logistic方程进行了比较，指出了以营养动力学为基础的崔—Lawson模型关于生物物种与营养环境之间关系的内涵思想，从而揭示了崔—Lawson模型比logistic方程之所以深刻的关键所在。本文通过对棕色固氮菌的菌体培养实验，系统地验证了以营养动力学为基础的崔—Lawson模型思想，并且对实验数据分别进行了崔—Lawson模型及logistic方程拟合。对两个模型拟合出的残差平方和进行了比较。证实崔—Lawson模型比logistic方程更适合于对实验资料的描述。并且随着营养水平逐渐降低，logistic方程拟合的残差平方和逐渐减小，从而说明只有在营养水平低的情况下，才适合用logistic方程，而通常情况下，用logistic方程是不合适的。

Influence of processing medium on frictional wear properties of ball bearing steel prepared by laser surface melting coupled with bionic principles

Coupling with bionic principles, an attempt to improve the wear resistance of ball bearing steel (GCr15) with biomimetic units on the surface was made using a pulsed Nd: YAG laser. Air and water film was employed as processing medium, respectively. The microstructures of biomimeitc units were examined by scanning electron microscope and X-ray diffraction was used to describe the microstructure and identify the phases as functions of different mediums as well as water film with different thicknesses. The results indicated that the microstructure zones in the biomimetic specimens processed with water film were more refined and had better wear resistance increased by 55.8% in comparison with that processed in air; a significant improvement in microhardness was achieved by laser surface melting. The application of water film provided considerable microstructural changes and much more regular grain shape in biomimetic units, which played a key role in improving the wear resistance of ball bearing steel. (c) 2010 Elsevier B.V. All rights reserved.

Multiple expansions of C-4 plant biomass in East Asia since 7 Ma coupled with strengthened monsoon circulation

IEECAS SKLLQG

Development and transition of spiral wave in the coupled Hindmarsh-Rose neurons in two-dimensional space

The dynamics and the transition of spiral waves in the coupled Hindmarsh-Rose (H-R) neurons in two-dimensional space are investigated in the paper. It is found that the spiral wave can be induced and developed in the coupled HR neurons in two-dimensional space, with appropriate initial values and a parameter region given. However, the spiral wave could encounter instability when the intensity of the external current reaches a threshold value of 1.945. The transition of spiral wave is found to be affected by coupling intensity D and bifurcation parameter r. The spiral wave becomes sparse as the coupling intensity increases, while the spiral wave is eliminated and the whole neuronal system becomes homogeneous as the bifurcation parameter increases to a certain threshold value. Then the coupling action of the four sub-adjacent neurons, which is described by coupling coefficient D', is also considered, and it is found that the spiral wave begins to breakup due to the introduced coupling action from the sub-adjacent neurons (or sites) and together with the coupling action of the nearest-neighbour neurons, which is described by the coupling intensity D.

Constrain intergalactic medium from the SZ effect map

In this paper, we try to detect the SZ effect in the 2MASS DWT clusters and less bound objects in order to constrain the warm-hot intergalactic medium distribution on large scales by cross-correlation analysis. The results of both observed WMAP and mock SZ effect map indicate that the hot gas distributes from inside as well as outside of the high density regions of galaxy clusters, which is consistent with the results of both observation and hydro simulation. Therefore, the DWT measurement of the cross-correlation would be a powerful tool to probe the missing of baryons in the universe.