影响激光驱动器注入镜组特性的误差因素分析

研究了惯性约束大功率激光聚变驱动器注入镜组特性影响因素，分析表明透镜的几何尺寸公差、透镜装配公差和镜组在线安装公差等因素对镜组焦距公差、焦斑分布、波像差方面的特性影响较大。针对影响镜组特性的主要因素，建立了镜组特性影响分析的相关数学模型，并基于MatIab和Zemax软件平台对模型进行模拟计算，结果表明数学模型可以保证镜组特性需要的制造、安装公差。

铝合金平面薄壁件动态特性研究与建模

针对三类常见的铝合金材料(6061/7050/7075)薄壁件,基于锤击实验的方法,开展了考虑切削路径频响函数模态参数的识别研究,获得了其动态特性影响因素,并构建了考虑切削振动的薄壁件动态特性模型。研究结果表明:6061/7050铝合金薄壁件固有频率随切削路径向工件中线靠近而增加,7075铝合金薄壁件则变化不明显。该文所构建模型可有效预测薄壁件加工路径上模态参数的变化。

地道风系统的研究现状及进展

作为可再生能源利用技术,地道风系统已被广泛应用到建筑空调通风领域中。本文首先对地道风系统换热特性的研究进展进行总结概括,然后对当前地道风系统性能影响因素的研究成果进行归纳汇总,包括地道参数、地道结构、土壤特性和通风时间,再对四种与地道风系统相结合的复合式技术进行介绍,最后,基于上述研究成果对今后地道风系统的发展方向进行展望。

螺杆泵的选择、使用中的问题研究

伴随着螺杆泵举升方式应用规模的日益扩大,常规地面驱动螺杆泵装置存在合理选用的问题:螺杆泵的合理选用、带泵电机的合理选用等。如果选用不当,会造成电机和螺杆泵的效率下降、能耗过大;存在安全隐患等问题。

Some advances on investigating friction characteristics of rolling guide ways

A review of research on hyste-resis and stick-slip is presented in this paper. Devices for investigating friction hysteresis and stick-slip of linear rolling guide ways are introduced,as well as some experiment results and conclusions,and some factors impacting on stick-slip are also exhibited.

Variation of Floods Characteristics and Their Responses to Climate and Human Activities in Poyang Lake, China

The Poyang Lake is one of the most frequently flooded areas in China. Understanding the changing characteristics of floods as well as the affecting factors is an important prerequisite of flood disaster prevention and mitigation. The present study identified the characteristics variations of historical floods in the Poyang Lake and their tendencies based on the Mann-Kendall(M-K) test, and also investigated the related affecting factors, both from climate and human activities. The results revealed that the highest flood stages, duration as well as hazard coefficient of floods showed a long-term increasing linear trend during the last 60 years with the M-K statistic of 1.49, 1.60 and 1.50, respectively. And, a slightly increasing linear trend in the timing of the highest stages indicated the floods occurred later and later during the last six decades. The rainfall during the flood season and subsequent discharges of the Changjiang(Yangtze) River and runoff from the Poyang Lake Basin were mainly responsible for the severe flood situation in the Poyang Lake in the 1990 s. In addition, the intensive human activities, including land reclamation and levee construction, also played a supplementary role in increasing severity of major floods. While, the fewer floods in the Poyang Lake after 2000 can be attributed to not only the less rainfall over the Poyang Lake Basin and low discharges of the Changjiang River during flood periods, but also the stronger influences of human activity which increased the floodwater storage of the Poyang Lake than before.

STUDY ON MAJOR FACTORS INFLUENCINGSPONTANEOUS COMBUSTION OF COAL

This paper theoretically analyzes major factors influencing spontaneous combustion of coal, such as molecule structure of coal, porosity, temperature, concentration of oxygen, coal thickness, velocity of face advance, and so on; and probes into how they affect the process of spontaneous combustion of coal, which is of momentous significance to predict or control self ignition of coal.

Weigh in Motion Based on Parameters Optimization

Dynamic tire forces are the main factor affecting the measurement accuracy of the axle weight of moving vehicle.This paper presents a novel method to reduce the influence of the dynamic tire forces on the weighing accuracy.On the basis of analyzing the characteristic of the dynamic tire forces,the objective optimization equation is constructed.The optimization algorithm is presented to get the optimal estimations of the objective parameters.According to the estimations of the parameters,the dynamic tire forces are separated from the axle weigh signal.The results of simulation and field experiments prove the effectiveness of the proposed method.

SAGD Optimization for Heterogeneous Reservoir

This paper demonstrates the use of a commercial simulator as a tool with which to optimize the SAGD （steam-assisted gravity drainage） start-up phase process. The factors affecting the start-up phase are the prime targets. Among the key investigated factors are wellbore geometry effects, reservoir heterogeneity and circulation phase length. Each of the parameters was investigated via steam chamber development observation along the well pair length and the cross sections in the mid, toe and heel areas. In addition, the cumulative recovery in given time, steam-to-oil ratio and CDOR （calendar day oil rate） production data are used to backup the observations produced in the simulated model. Furthermore, an additional component developed during the research is a statistical modification of a layer cake model with which to create a heterogeneous reservoir to represent real reservoir conditions, based on Monte Carlo＇s simulation.

Cavity flow regime for spillway aerators

It is well known that the effect of air entrainment for cavitation damage controls is related not only to the air discharge into aerator devices but also the flow regime of the cavity below them.On the basis of the hydraulic characteristics of the flow,the aerator devices were for the first time classified.The theoretical considerations were performed about the jet length and cavity flow regime with the influencing factors.Comparing with the behavior of the flow through the aerator of discharge tunnels,the flow regimes of the cavity below spillway aerators were experimentally investigated,and the empirical expressions were presented to identify the conversions of the cavity flow regimes,including fully filled cavity,partially filled cavity,and net air cavity.Some issues of the design of the aerator devices were suggested in the present work.

Process optimization for the enhanced stability of diclofenac potassium granules and capsules

This study aimed to investigate the effects of different process parameters on the physical properties, in vitro dissolution rate, and short and long-term stability of diclofenac potassium（DFP） granules and capsules. DFP granules exhibited low total amounts of impurities when prepared through the wet granulation method using a granulating solvent with a low water/ethanol ratio. The impurities of the wet DFP mass dried at 70 ℃ were higher than those dried at 50 ℃ or 60 ℃. DFP granules were stable under strong light exposure during preparation. DFP granules prepared using a granulating solvent with a 1：4 water/ethanol ratio had a relatively smaller particle size and higher angle of repose than those prepared using granulating solvents with other water/ethanol ratios. The dissolution rate of DFP capsules prepared using four different water/ethanol ratios was less than 2% after 10 min of dissolution and increased to 95% within 30 min of dissolution. The total amount of drug impurities of DFP capsules prepared using a granulating solvent with 1：4 water/ethanol ratio was considerably lower than those of DFP capsules prepared using a granulating solvent with a 1：0 water/ethanol solvent ratio. Regardless of the water/ethanol ratio, the capsules showed poor stability when exposed to high temperature（60 ℃） and strong light（4500±500 Lux） for 10 days, but were relatively stable at high humidity（92.5% RH）. The results of the long-term stability（25±2 ℃ and 60%±10% relative humidity） study showed that DFP granules were more stable than DFP capsules, and were stable for 12 months. The type of encapsulating material did not affect the 2-month stability of DFP. DFP granules are sensitive to granulating solvent and drying temperature and DFP capsules should be stored away from high temperature and strong light.

Factors Affecting Small Axial Cooling Fan Performance

Many factors such as outer diameter, hub ratio, blade numbers, shape and stagger angle affect the performance of small cooling fans. A small cooling fan was simulated using CFD software for three blade stagger angles （30.5°, 37.5°, 44.5°）and obtained the internal flow field and the static characteristics. Research indicated that the stagger angle has an obvious effect on the static characteristics of a fan. For flow rates below 0.0104 mVs, total pressure is the greatest when the stagger angle is 37.5°; flow rates higher than 0.0104 m^3/s, the total pressure is greatest when the stagger angle is 44.5° For the same flow rates, the velocity at inlet of pressure surface increases with in- creasing stagger angle, but the change of velocity on the suction surface is very small. For one model, vortices and the speed of revolution surfaces decrease with tip clearance increasing. But for other three models, increasing the stagger angle, the vortex intensity and speed of revolution surfaces at same height tip clearance increases, simultaneously, the position of vortex offset from the top of the rotor blade to the suction surface.

Analysis on the influencing factors of mechanical characteristics of jointless turnout group in ballasted track of high-speed railway

Turnouts are in close proximity to each other in the stations of high-speed railway.The stress and deformation of those turnouts which are laid nearby are influenced mutually and therefore those turnouts should be considered together.On the basis of finite element method,according to No.18 jointless turnout with swing nose frog in the ballasted track of high-speed railway,a finite element calculating model of jointless turnout group coupling the longitudinal,lateral and vertical directions is established.The influencing factors,for instance the number of turnouts,connection form,length of intermediate straight line and ballast bed longitudinal resistance,on the mechanical characteristics of turnout,transverse deformation of switch rail and range of rail temperature for laying turnout are analyzed in this paper.The results show that more turnouts result in more obvious interaction between them when the lengths of intermediate straight line are the same;more significant influence between the turnouts with the connection form of head-to-head is produced compared to that of head-to-end;from the perspective of statics,influence between turnouts could be ignored basically if the intermediate straight line is over 50 m;bigger longitudinal resistance of ballast bed leads to less influence between the turnouts.

Experimental study on fouling characteristics and influence factors of spiral-grooved tube

In this paper,we carried out a series of experiments on fouling characteristics of 6 kinds of spiral-grooved tubes to investigate the impact of hardness,temperature and structure parameters of cold water on fouling characteristics of spiral-grooved tube.Experimental results showed that when cold-water temperature decreased,fouling resistance of spiral-grooved tube also decreased.Asymptotic fouling resistance increased accompanied with increase of cold-water hardness.However,the asymptotic fouling resistance appeared to reduce when hardness increased to some extent.Geometric parameters of spiral-grooved tubes had remarkable effect on fouling resistance,which showed a tendency of decrease with increase of groove depth and decrease of pitch.In this study,the minimum asymptotic fouling resistance was observed in the spiral-grooved tube with small pitch and large groove depth.