“神光-Ⅱ”第九路终端光学系统稳定性分析

在“神光-Ⅱ”装置上进行先进高能多功能激光束系统（简称第九路）研制工程中,由于在原ICF靶室上又增加了输入“汤姆逊探针光”和“X光背光照明探针光”的锥形真空套筒及其终端光学元件,导致原有靶室结构的变化,可能会引入新的不稳定因素.通过有限元分析方法,建立有限元分析模型,进行优化设计.通过位移传感器测量结果可知,第九路终端光学元件径向窜动所引起的打靶误差最大值为2.110 μm,小于“神光-Ⅱ”靶场终端光学系统的最大允许误差值7.785 μm.

Keyword spotting system based on biomimetic pattern recognition

The mandarin keyword spotting system was investigated, and a new approach was proposed based on the principle of homology continuity and point location analysis in high-dimensional space geometry theory which are both parts of biomimetic pattern recognition theory. This approach constructed a hyper-polyhedron with sample points in the training set and calculated the distance between each test point and the hyper-polyhedron. The classification resulted from the value of those distances. The approach was tested by a speech database which was created by ourselves. The performance was compared with the classic HMM approach and the results show that the new approach is much better than HMM approach when the training data is not sufficient.

归因任务中预期强度水平对结果评价的影响

Previous researches has shown that two components of the event- related brain potential, the feedback negativity (FRN) and P300, are related to outcome evaluation. So far, the nature of the outcome evaluation reflected by FRN and the significance of P300 remains unknown. Some studies found that the process of outcome evaluation may be related to the expectation, and the FRN may be affected by the intensity levels of the expectation for the outcome. To address these issues, the present study will start on two aspects: (1)This study required 39 participants to make attribution about their performance during a task, the aim was to assess the levels of the expectations for the outcome under four conditions in the attribution task. The main finding is that, the expectations for monetary reward under four conditions are scaled. (2)Based on the results of the first study, this study also required 16 participants to make attribution about their performance during a task. A functional dissociation was observed, with the FRN affected by the intensity levels of the expectation for the outcome, while the P300 sensitive to the degree of emotion the participants experienced. Dipole source location analysis showed that the most likely neural generator of FRN and P300 is the cingulate cortex, suggesting that FRN might reflect cognitive conflict when the actual outcome is different from the expectation, and P300 is related to the emotion processing of outcome stimuli. These results suggest that there is a functional dissociation between FRN and P300.

Numerical Analysis of Rainfall Infiltration in the Slope with a Fracture

With the finite volume method, a 2D numerical model for seepage in unsaturated soil has been established to study the rainfall infiltration in the fractured slope.The result shows that more rain may infiltrate into the slope due to existing fracture and then the pore pressure rises correspondingly. Very probably, it is one of the crucial factors accounting for slope failure. Furthermore a preliminary study has been conducted to investigate the influence of various fracture and rainfall factors such as the depth, width and location of a crack, surface condition, rainfall intensity and duration. Pore pressure and water volumetric content during the transient seepage are carefully examined to reveal the intrinsic mechanism.

Instability Analysis of Nonlinear Surface Waves in a Circular Cylindrical Container Subjected to a Vertical Excitation

Singular perturbation theory of two-time scale expansions was developed both in inviscid and weak viscous fluids to investigate the motion of single surface standing wave in a liquid-filled circular cylindrical vessel, which is subject to a vertical periodical oscillation. Firstly, it is assumed that the fluid in the circular cylindrical vessel is inviscid, incompressible and the motion is irrotational, a nonlinear evolution equation of slowly varying complex amplitude, which incorporates cubic nonlinear term, external excitation and the influence of surface tension, was derived from solvability condition of high-order approximation. It shows that when forced frequency is low, the effect of surface tension on mode selection of surface wave is not important. However, when forced frequency is high, the influence of surface tension is significant, and can not be neglected. This proved that the surface tension has the function, which causes free surface returning to equilibrium location. Theoretical results much close to experimental results when the surface tension is considered. In fact, the damping will appear in actual physical system due to dissipation of viscosity of fluid. Based upon weakly viscous fluids assumption, the fluid field was divided into an outer potential flow region and an inner boundary layer region. A linear amplitude equation of slowly varying complex amplitude, which incorporates damping term and external excitation, was derived from linearized Navier-Stokes equation. The analytical expression of damping coefficient was determined and the relation between damping and other related parameters (such as viscosity, forced amplitude and depth of fluid) was presented. The nonlinear amplitude equation and a dispersion, which had been derived from the inviscid fluid approximation, were modified by adding linear damping. It was found that the modified results much reasonably close to experimental results. Moreover, the influence both of the surface tension and the weak viscosity on the mode formation was described by comparing theoretical and experimental results. The results show that when the forcing frequency is low, the viscosity of the fluid is prominent for the mode selection. However, when the forcing frequency is high, the surface tension of the fluid is prominent. Finally, instability of the surface wave is analyzed and properties of the solutions of the modified amplitude equation are determined together with phase-plane trajectories. A necessary condition of forming stable surface wave is obtained and unstable regions are illustrated. (c) 2005 Elsevier SAS. All rights reserved.

Comparison Between Lurr And State Vector Analysis Before Strong Earthquakes In Southern California Since 1980

There are seven strong earthquakes with M >= 6.5 that occurred in southern California during the period from 1980 to 2005. In this paper, these earthquakes were studied by the LURR (Load/Unload Response Ratio) method and the State Vector method to detect if there are anomalies before them. The results show that LURR anomalies appeared before 6 earthquakes out of 7 and State Vector anomalies appeared before all 7 earthquakes. For the LURR method, the interval between maximum LURR value and the forthcoming earthquake is 1 to 19 months, and the dominant mean interval is about 10.7 months. For the State Vector method, the interval between the maximum modulus of increment State Vector and the forthcoming earthquake is from 3 to 27 months, but the dominant mean interval between the occurrence time of the maximum State Vector anomaly and the forthcoming earthquake is about 4.7 months. The results also show that the minimum valid space window scale for the LURR and the State Vector is a circle with a radius of 100 km and a square of 3 degrees 3 degrees, respectively. These results imply that the State Vector method is more effective for short-term earthquake prediction than the LURR method, however the LURR method is more effective for location prediction than the State Vector method.

Heat Transfer of Aviation Kerosene at Supercritical Conditions

The heat transfer characteristics of China no. 3 kerosene were investigated experimentally and analytically under conditions relevant to a regenerative cooling system for scramjet applications. A test facility developed for the present study can handle kerosene in a temperature range of 300-1000 K, a pressure range of 2.6-5 MPa, and a mass How rate range of 10-100 g/s. In addition, the test section was uniquely designed such that both the wall temperature and the bulk fuel temperature were measured at the same location along the flowpath. The measured temperature distributions were then used to analytically deduce the local heat transfer characteristics. A 10-component kerosene surrogate was proposed and employed to calculate the fuel thermodynamic and transport properties that were required in the heat transfer analysis. Results revealed drastic changes in the fuel flow properties and heat transfer characteristics when kerosene approached its critical state. Convective heat transfer enhancement was also found as kerosene became supercritical. The heat transfer correlation in the relatively low-fuel-temperature region yielded a similar result to other commonly used jet fuels, such as JP-7 and JP-8, at compressed liquid states. In the high-fuel-temperature region, near and beyond the critical temperature, heat transfer enhancement was observed; hence, the associated correlation showed a more significant Reynolds number dependency.

Analysis for temperature and pressure fields in process of hydrate dissociation by depressurization

An improved axisymmetric mathematic modeling is proposed for the process of hydrate dissociation by depressurization around vertical well. To reckon in the effect of latent heat of gas hydrate at the decomposition front, the energy balance equation is employed. The semi-analytic solutions for temperature and pressure fields are obtained by using Boltzmann-transformation. The location of decomposition front is determined by solving initial value problem for system of ordinary differential equations. The distributions of pressure and temperature along horizontal radiate in the reservoir are calculated. The numeric results indicate that the moving speed of decomposition front is sensitively dependent on the well pressure and the sediment permeability. Copyright (C) 2010 John Wiley & Sons, Ltd.

CFD analysis of thermodynamic cycles in a pulse tube refrigerator

The objectives of this paper are to study the thermodynamic cycles in an inertance tube pulse tube refrigerator (ITPTR) by means of CFD method The simulation results show that gas parcels working in different parts of ITPTR undergo different thermodynamic cycles The net effects of those thermodynamic cycles are pumping heat from the low temperature part to the high temperature part of the system The simulation results also show that under different frequencies of piston movement the gas parcels working in the same part of the system will undergo the same type of thermodynamic cycles The simulated thermal cycles are compared with those thermodynamic analysis results from a reference Comparisons show that both CFD simulations and theoretical analysis predict the same type of thermal cycles at the same location However only CFD simulation can give the quantitative results while the thermodynamic analysis is still remaining in quality (C) 2010 Elsevier Ltd All rights reserved

Vacuum window of intermediate energy heavy-ion microbeam irradiation facility

The beam must be extracted into the air through the vacuum window to irradiate the living cell. In the window design, the material and thickness must be chosen to compromise the beam spot size broadening and the window safety. The structure-static analysis on the window of different structures and materials is done with the finite element analysis method, and the deformation and the equivalent stress axe simulated. The safety of these candidates is investigated using the intensity theory. In addition, the small angle scattering and the transverse range of ions are simulated using SRIM code, including all the effects on the beam spot size broadening, such as the incident ion energy, the material and the thickness of the window and the air composing. At last, the appropriate vacuum windows are presented, including the structure, material and thickness.

Domain analysis of the Edwardsiella tarda ferric uptake regulator

Recent studies have shown that the ferric uptake regulator (Fur) of Edwardsiella tarda (Fur(Et)) shares high sequence identity with the Escherichia coli Fur (Fur(Ec)) at the N-terminal DNA-binding region. In the present study, the functional importance of the C-terminal region of Fur(Et) was investigated. It was found that Fur(Et) bearing deletion of the C-terminal 12 residues still possesses most of the repressor activity, whereas Fur(Et) bearing deletions of the C-terminal 16 and more than 16 residues are severely affected in activity. Domain swapping analyses indicated that the chimeric Fur proteins (Et75Ec73 and Et75Vh74) consisting of the N-terminal 1-75 region of Fur(Et) fused to the C-terminal 76-148 region of Fur(Ec) and the C-terminal 76-149 region of the Vibrio harveyi Fur (Fur(Vh)), respectively, are fully active. C92 of Fur(Ec) and C137 of Fur(Vh), which are functionally essential in Fur(Ec) and Fur(Vh), respectively, are also essential in Et75Ec73 and Et75074, respectively. Further study identified an artificial Fur protein, EtMF54, which is composed of the N-terminal 49 residues of Fur(Et) and five artificial residues. Compared to Fur(Et), EtMF54 possesses partial Fur activity that is iron-dependent. These results (I) indicate that there exist certain functional/structural compatibilities among Fur(Et), Fur(Ec), and Fur(Vh) at the C-terminal region; (ii) provide insights to the potential location of the regulatory ion-binding site of Fur(Et).

Preliminary analysis of grain-size populations with environmentally sensitive terrigenous components in marginal sea setting

Terrigenous components were separated from the bulk sediment of Core A7 from the Okinawa Trough and Core A37 from the Ryukru Trench and grain-size distributions of these sub-samples were analyzed. Based upon an analysis of the grain-size data of the two sedimentary sequences, grain-size populations are identified to be sensitive to sedimentary environmental changes. The modal values and size ranges of the two main grain-size populations in Core A7 are evidently different from those of Core A37, indicating the spatial variability of sediment sources and transport processes between the two places. The downcore variations in the content of the environmentally sensitive grain-size populations reveal that during the accumulation of sedimentary material the environment remained relatively stable at the site where Core A7 was collected, except for the apparent events for the formation of two turbidite layers and a volcanic ash layer. However, the sedimentary sequence of Core A37 shows six sedimentary cycles, indicating a highly variable sedimentary environment at this location.