Production of thick-walled hollow glass microspheres for inertial confinement fusion targets by sol-gel technology

To fabricate thick-walled hollow glass microspheres(HGMs)for inertial confinement fusion(ICF)targets by sol-gel technology,we investigated the effects of glass composition,blowing agent,refining temperature,pressure and composition of furnace atmosphere on the wall thickness of HGMs by numerical simulation and experiments.The results showed that the residence times of the thick-walled HGMs in the encapsulating and refining phases decreased with the increase of wall thickness of HGMs.As a response to this ch...     

Airside fin efficiencies for finned-tube heat exchangers with forced convection

The heat transfer and mass transfer fin efficiencies were analyzed numerically to show that popular models for heat transfer fin efficiency for circular fins are not always reasonable.The numerical results show that the effective heat transfer area of a circular fin increases several times faster than that of a straight fin for the same tube radius.Then,a simple but accurate heat transfer fin efficiency model was developed and verified by numerical results for a wide range of fin designs.This model predicts...     

Multi-level multi-area hybrid automatic voltage control system and its trial operation in Northeast China Grid

In order to coordinate automatic voltage control(AVC)systems of a large interconnected system,a multi-level multi-area hybrid automatic voltage control(MLMA-HAVC)system was constructed.This system began its trial operation in the Northeast China Grid in January 2010,and for the first time in China and abroad it realized automatic close-loop control of multi-area and multi-level interconnected power grid and multi-objective self-approaching optimization in aspects of security,high quality and economic operat...     

Analysis of the effect of regional lateral inflow on the flood peak of the Three Gorges Reservoir

The Three Gorges Region(TGR),located at the lower reach of the Upper Yangtze River Basin(UYRB) in China,suffers from heavy rainstorm frequently.The runoff generated from TGR composes an important part of the total flood at the famous Three Gorges Reservoir(TGRe).During the severe flood period in 1954,for example,the water from TGR accounted for up to 13.2% of the 30-days maximum flood volume of the UYRB.Considering the short and steep tributaries with rapid concentration,the regional lateral inflow(RLI) may...     

Iterative Learning Control Algorithm with a Fixed Step

Iterative Learning Control (ILC) captures interests of many scholars because of its capability of high precision control implement without identifying plant mathematical models, and it is widely applied in control engineering. Presently, most ILC algorithms still follow the original ideas of ARIMOTO, in which the iterative-learning-rate is composed by the control error with its derivative and integral values. This kind of algorithms will result in inevitable problems such as huge computation, big storage capacity for algorithm data, and also weak robust. In order to resolve these problems, an improved iterative learning control algorithm with fixed step is proposed here which breaks the primary thought of ARIMOTO. In this algorithm, the control step is set only according to the value of the control error, which could enormously reduce the computation and storage size demanded, also improve the robust of the algorithm by not using the differential coefficient of the iterative learning error. In this paper, the convergence conditions of this proposed fixed step iterative learning algorithm is theoretically analyzed and testified. Then the algorithm is tested through simulation researches on a time-variant object with randomly set disturbance through calculation of step threshold value, algorithm robustness testing,and evaluation of the relation between convergence speed and step size. Finally the algorithm is validated on a valve-serving-cylinder system of a joint robot with time-variant parameters. Experiment results demonstrate the stability of the algorithm and also the relationship between step value and convergence rate. Both simulation and experiment testify the feasibility and validity of the new algorithm proposed here. And it is worth to noticing that this algorithm is simple but with strong robust after improvements, which provides new ideas to the research of iterative learning control algorithms.     

饱水石灰岩骨架和流体弹性参数的估算

本文利用Niu等提出的基于临界孔隙度模型的组分弹性参数数值计算方法,把测试岩石样品的孔隙度、整体密度、纵波速度和横波速度作为数值计算的输入数据,运用"双线性数值计算方法"反演求出临界点、流体和骨架的12个弹性参数。具体做法是:基于临界孔隙度模型,给出三组线性关系,即密度—孔隙度,整体剪切模量—孔隙度,整体纵波模量—孔隙度,上述每组线性关系分别以孔隙度作为自变量和因变量得到两个线性方程,再把两个方程计算的结果进行加权平均得到相关的弹性参数估算值,并结合饱水石灰岩样品数据实现了弹性参数估算。数值计算结果表明,由数值计算得到的弹性参数与测试弹性参数的均值和方差相差甚微,特别是密度数据的偏差均值更小,说明文中的数值计算结果是可靠的。     

大古2井超深复杂井钻井液技术

大古2井为大涝坝构造山前构造的一口重点探井,完钻井深为6 702 m。该井二开(φ311.2 mm)裸眼井段长(2 500～5 300 m),钻遇多套高压盐水层和石膏层;三开(φ215.9 mm,5 300～6 552.53 m)存在多套压力体系,地层渗透性强,高密度条件下压差卡钻的风险大。现场采用阳离子乳液聚合物钻井液,并根据不同井下复杂情况加强钻井液性能维护处理,解决了遇阻卡钻和地层出盐水等复杂问题;通过添加超低渗透处理剂和屏蔽暂堵剂,强化对地层的封堵,解决了三开施工中出现的压差卡钻风险,保证了现场安全施工。     

35MHz鉴频器的混合集成电路模块化设计

在用分离元器件设计的３５ＭＨｚ鉴频器的基础上，介绍了一种混合集成电路模块化设计方案，最后给出了实验测试结果，并与用分离元件设计的鉴频器做了比较。     

汽车变速器模糊综合评价系统的研究

运用模糊综合评价方法对汽车变速器的燃油经济性、动力性、寿命和噪声目标进行了总体评价,结合CA141 汽车变速器对该评价系统进行验证,其结果能客观地反映汽车变速器的性能等级     

Studies on Acid Leaching Methods for Fine Metal Powder Production

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