Pragmatical generalized synchronization of chaotic systems with uncertain parameters by adaptive control

A new kind of generalized synchronization of two chaotic systems with uncertain parameters is proposed. Based on a pragmatical asymptotical stability theorem and an assumption of equal probability for ergodic initial conditions, an adaptive control law is derived so that it can be proved strictly that the common null solution of error dynamics and of parameter dynamics is actually asymptotically stable, i.e. these two identical systems are in generalized synchronization and the estimated parameters approach the uncertain values. It is called pragmatical generalized synchronization. Finally, two numerical examples are studied for two Quantum-CNN oscillator chaotic systems to show the effectiveness of the proposed generalized synchronization strategy with a double Duffing chaotic system as a goal system.     

Study of photoconductivity and photoluminescence of organic/porous silicon complexes

In this paper, time-varying photoconductivity (PC) and the photoluminescence (PL) of different complexes were studied. Due to thick polymer layer hindering light penetrating into porous silicon (PS) layer, intrinsic PS luminescence in polymer/PS system disappeared. The physical origin of PL may be related to the recombination mechanisms involving surface defect states such as silicon oxide, siloxene. Due to carrier transfer controlled by different energy barrier, different devices prepared from different doped Si wafer showed opposite current-voltage characteristic.     

Microstructures and electrical properties of La0.8Sr0.2MnO3 films synthesized by sol-gel method

La_0.8Sr_0.2MnO₃ (LSMO) thin films were fabricated on alumina substrates by an improved sol-gel dip-coating process. It was found that multiple dip-coating process could not be performed until the pre-firing temperature reached 600 °C. Different amounts of LSMO powders were added to precursor solution with an aim to avoid cracks in LSMO thin films during calcining caused by the shrinkage mismatch between the film and the substrate. The structure and surface morphology of the films prepared from precursors with and without LSMO powders were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). It was found that the addition of 56.4 wt.% LSMO powders into the sol-gel precursor solution significantly modified the microstructure of films. A single LSMO perovskite phase was obtained on alumina substrate after calcining at 800 °C for 4 h by the improved sol-gel method. The sheet resistance of the films prepared with different processing parameters was measured by four-point dc method. Results indicated that the sheet resistance of films decreased with increasing the number of coating applications and the amount of LSMO powders.     

Grey screening-photovoltaic soliton-induced waveguides

This paper shows that waveguides induced by grey screening-photovoltaic solitons are always single mode for all intensity ratios, which are the ratio between the peak intensity of the soliton and the dark irradiance. It finds that the confined energy near the centre of the grey soliton and the propagation constant of the guided mode increase monotonically with increasing intensity ratio. On the other hand, when the soliton greyness increases, the confined energy near the centre of the grey soliton and the propagation constant of the guided mode reduce monotonically. When the bulk photovoltaic effect is neglected for short circuits, these waveguides become waveguides induced by grey screening solitons. When the external bias field is absent, these waveguides become waveguides induced by grey photovoltaic solitons.[第一段]     

Ag/Cu(111)与Au/Cu(111)体系异质外延岛演化过程中的应变释放及其对Moiré结构形成的影响

采用嵌入原子方法的原子间相互作用势，利用分子动力学模拟方法研究了Au/Cu(111)和Ag/Cu (111)体系的异质外延结构特征以及外延岛形貌和应变释放的演化过程. 通过对比Au/Cu(111)和Ag/Cu (111)体系的异质外延结构及外延岛演化行为，揭示了导致Ag/Cu (111)体系中异质外延层形成Moiré结构的微观物理机理及其与外延体系的宏观物理特性之间的关系. 研究结果显示，外延岛原子与基体表面原子之间的界面结合强度是形成Moiré结构的重要因素，异质外延体系的界面结合强度取决于二者的合金熔解热. 当异质外延体系的合金熔解热为正值时，界面结合强度较弱，有利于Moiré结构的形成. 同时，外延岛原子之间的相互作用决定着外延岛的面内弛豫行为，对Moiré结构的形成有一定的影响. 外延岛的面内弛豫行为与外延层和基体之间的相对刚度有关，弹性模量较大的外延层具有较强的延展能力，对Moiré结构的形成有利. 此外，Moiré结构的形成与外延岛的尺度有关，主要是外延岛边界原子的钉扎作用对外延岛内原子弛豫行为的约束作用的影响.     

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.     

主编的话

Happy New Year! Happy New Year again! This year is very special for CJCP since it is the 20th anniversary. We have seen a tremendousdevelopment in the field of chemical physics in China in the last 20 years. CJCP has always been there in this important period of development in Chinese science, and CJCP has made significant and important contributions to the development of the chemical physics research field in China. And we certainly will continue to do so in the future. In the beginning of last year, we changed the journal into a full English journal in an effort to enhance the journal impact in the international scientific community. In this transition period, CJCP has encountered many difficulties, and we have also made great progresses. We deeply believe that making CJCP a full English journal is an important step to increase its influence in the international research community. We hope this is the moment of a new start for the great tradition of CJCP to serve the Chinese chemical physics and physical chemistry community, and beyond. Now, our new web based editorial and review system is in place, we hope CJCP will serve our community in a more efficient and direct way (Website: http://cjcp.ustc.edu.cn). With the support of the chemical physics and physical chemistry community, I am confident that this journal will make more significant contributions to the development of the chemical physics researchfield. At this 20th anniversary of CJCP, I want to take this special opportunity to thank many people who have lead this journal through difficulties and triumphs in the most part of the last 20 years, especially the former Editor-in-Chief, Professor Nanquan Lou, and the former senior associate editor, Prof. Shuqin Yu. And I also want to thank the editorial staff members who have made great efforts in producing a high quality scientific journal. At last, I hope everybody who cares about the Chinese chemical physics development will support our effort to make this journal better. Xue-ming Yang Editor-in-Chief February 12, 2007     

氟诺喹酮类药物分子抗肺炎克雷伯氏菌的结构活性关系研究

利用主成分分析和分层聚类分析方法研究了具有抗肺炎克雷伯氏菌的氟诺喹酮类药物分子的结构活性关系．主成分分析方法表明变量ELUMO、ΔEHL、μ、Q3、Q5、QA、lgP、MP、MR能够有效地对抗肺炎克雷伯氏菌的氟诺喹酮类药物进行分类．分层聚类方法和主成分分析方法的结果一致．这表明两种方法都能够对新的具有抗肺炎克雷伯氏菌的氟诺喹酮类药物的分类提供一个可信的规律．利用主成分分析法和分层聚类分析法对其他4个氟诺喹酮类药物分子进行分析，结果都表明有三个药物分子具有较强的抗肺炎克雷伯氏菌活性，此结果和临床结果相吻合．     

Hollow glass microspheres coated with CoFe2O4 and its microwave absorption property

Spinel CoFe₂O₄ coating on the surface of hollow glass microspheres of low density was synthesized by co-precipitation method. The phase structures, morphologies, particle size, shell thickness, chemical compositions of the composites have been characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and energy dispersive X-ray spectroscopy (EDS). The results show that CoFe₂O₄ coating on hollow glass microspheres can be achieved, and the coating layers are constituted by CoFe₂O₄ nanoparticles of mean size ca. 10 nm. The as-synthesized powder materials were uniformly dispersed into the phenolic cement, then the mixture was pasted on metal plate with the area of 200 mm×200 mm as the test plate. The test of microwave absorption was carried out by the radar-absorbing materials (RAM) reflectivity far field radar cross-section (RCS) method. The results indicate that the coated CoFe₂O₄/hollow glass microspheres composites can be applied in lightweight and strong absorption microwave absorbers.     

Effects of the passivation of SiNx with various growth stoichiometry on the high temperature transport properties of the two-dimensional electron gas in AlxGa1−xN/GaN heterostructures

Effects of the passivation of SiN_x on the high temperature transport characteristics of the two-dimensional electron gas (2DEG) in unintentionally doped Al_xGa_1−xN/GaN heterostructures have been investigated by means of high temperature Hall measurements. The 2DEG density increases much after SiN_x passivation, and the increment is proportional to the Si content in SiN_x layer, indicating that the increment is mainly caused by ionized Si atoms at the SiN/Al_xGa_1−xN interface with dangling bonds or by Si atoms incorporated into the Al_xGa_1−xN layer during the SiN_x growth, which is approved by strain analysis and X-ray photoemission spectroscopy (XPS). There is lower 2DEG mobility at room temperature in a passivated sample than in an unpassivated one. However, the 2DEG mobility becomes to be higher in a passivated sample than in an unpassivated one when the temperature is above 250 °C, which is suggested to be caused by different subband occupation ratios in the triangular quantum well at the heterointerface before and after passivation.