声-光型界面自旋波与界面各向异性

在考虑了外磁场、界面各向异性后，详细研究了铁磁和反铁磁层间耦合下自旋双链系统中的声－光型界面自旋波及其存在的充要条件．在适当的界面各向异性条件下，系统中可以存在０、１或２个声－光型界面自旋波，并发现其能量随铁磁层间耦合强度的增大而升高，随反铁磁层间耦合强度的增大而降低．

Stochastic Resonance in a Single-Mode Laser Driven by Quadratic Colored Pump Noise:Effects of Biased Amplitude Modulation Signal

A single-mode laser noise model driven by quadratic colored pump noise and biased amplitude modulationsignal is proposed.The analytic expression of signal-to-noise ratio is calculated by using a new linearized procedure.Itis found that there are three different typies of stochastic resonance in the model:the conventional form of stochasticresonance,the stochastic resonance in the broad sense,and the bona fide SR.

INFLUENCE OF VIRTUAL PHOTON FIELD ON COLLAPSE AND REVIVAL PHENOMENON IN TWO PHOTON J C MODEL WITHOUT RWA

The time evolution of system in two photon Jaynes Cummings (J C) model without rotating waves approximation (RWA) is obtained by using the theory of ordinary differential equations. Based on the evolution, the mean value of the atom inversion operator 〈 S 3(t)〉 is gi ven. The influence of the “counter rotating term” on the collapse and revival phenomenon is discussed from the comparison between the cases with RWA and without RWA. It shows that the influence of the virtual photon field makes the quantum fluctuations appear on the collapse and revival phenomenon.

Surface roughness prediction model in ultrasonic vibration assisted grinding of BK7 optical glass

Pre-knowledge of machined surface roughness is the key to improve whole machining efficiency and meanwhile reduce the expenditure in machining optical glass components.In order to predict the surface roughness in ultrasonic vibration assisted grinding of brittle materials,the surface morphologies of grinding wheel were obtained firstly in the present work,the grinding wheel model was developed and the abrasive trajectories in ultrasonic vibration assisted grinding were also investigated,the theoretical model for surface roughness was developed based on the above analysis.The prediction model was developed by using Gaussian processing regression(GPR)due to the influence of brittle fracture on machined surface roughness.In order to validate both the proposed theoretical and GPR models,32sets of experiments of ultrasonic vibration assisted grinding of BK7optical glass were carried out.Experimental results show that the average relative errors of the theoretical model and GPR prediction model are13.11%and8.12%,respectively.The GPR prediction results can match well with the experimental results.

Modeling for Ethernet passive optical network receiver

A behavior model for the receiver of the Ethernet passive optical network（EPON） is presented. The model consists of a fiber, a photodetector, a transimpedance amplifier （TIA） followed by a limiting amplifier and a clock and data recovery＇ circuit （CDR）. Each sub-model is constructed based on the architecture of a circuit. The noise and jitter in each block such as shot noise, thermal noise, deterministic and random jitter are also considered. The performance of the whole receiver can be evaluated by the simulation of the behavior model, which is faster than the ordinary circuit model and more accurate than the analytical model. The whole model is implemented with C ＋＋ and simulated in Microsoft Visual C ＋＋ 6. 0. Using the Monte Carlo method, the EPON receiver is simulated. The simulation results show a good agreement with experimental ones.

Investigation of the Compressible Flow through the Tip-Section Turbine Blade Cascade with Supersonic Inlet

The contribution deals with the experimental and numerical investigation of compressible flow through the tip-section turbine blade cascade with the blade 54″ long. Experimental investigations by means of optical(interferometry and schlieren method) and pneumatic measurements provide more information about the behaviour and nature of basic phenomena occurring in the profile cascade flow field. The numerical simulation was carried out by means of the EARSM turbulence model according to Hellsten [5] completed by the bypass transition model with the algebraic equation for the intermittency coefficient proposed by Straka and P?íhoda [6] and implemented into the in-house numerical code. The investigation was focused particularly on the effect of shock waves on the shear layer development including the laminar/turbulent transition. Interactions of shock waves with shear layers on both sides of the blade result usually in the transition in attached and/ or separated flow and so to the considerable impact to the flow structure and energy losses in the blade cascade.

Primary angle closure glaucoma in Chinese and Western populations

OBJECTIVE: To review the major progress in primary angle closure glaucoma (PACG). METHODS: Contents of this article were selected from the original papers or reviews related to primary angle closure glaucoma published in Chinese and foreign journals. A total of 76 articles were selected from several hundred original articles or reviews. The content of selected articles is in accordance with our purpose and the authors are authorized scientists in the study of glaucoma. RESULTS: Primary angle closure glaucoma is the most common type of glaucoma in the Sino-Mongoloid population. PACG in Chinese can be classified into three types depending on the mechanism of angle closure: 1. Multimechanism: 54.8% of Chinese PACG is caused by co-existing factors. The pattern of angle closure appears to mainly be creeping closure. After iridectomy, almost 40% of the cases still manifest a positive response to the darkroom provocative test and progressive synechial closure or recurrent angle closure may occur. Several mechanisms are involved in this form of PACG such as pupillary blocking component, iris crowding component and anterior positioned ciliary body. These factors can coexist in the follow patterns: pupillary blocking and iris crowding coexist; pupillary blocking and anterior positioned ciliary body coexist or three of them co-exist. 2. Pupillary block: (38.1% of Chinese PACG) is caused by iris bombe due to pupillary block with acute or subacute attack. It responds well to iridectomy or laser iridotomy. 3. Non-pupillary blocking: (7.8% of Chinese PACG). They usually have a deeper anterior chamber, and tend to be younger (below 40 years of age). Angle closure in this form of PACG is caused by: iris crowding mechanism or/and anteriorly positioned ciliary body against iris root to angle. It is critical to distinguish multi-mechanism PACG from other types. The initial treatment for this type of PACG is also iridectomy, but after the pupillary block component is eliminated by iridectomy, the residual non-pupillary blocking components should be highlighted by a diagnostic treatment procedure or by a ultrasound biomicroscopy (UBM) provocative test. Finally, the role of UBM in the observation and evaluation of the mechanism of angle closure is discussed and future research directions on PACG in Asians are proposed. CONCLUSION: Chinese eyes have been recognized to be prone to the development of creeping angle closure. There is some direct evidence that creeping angle closure is caused by multiple mechanisms. Further study on this topic is needed.