增程型L波段风廓线雷达探测性能分析

风廓线雷达作为一种新型的大气风场探测设备，具有时间分辨率高、连续性和实时性好等特点，已广泛应用到各行业。文中首先分析了增程型L波段风廓线雷达的探测能力，简要介绍了该雷达的系统设计；然后，利用中国气象局海口站业务运行一年的观测数据，从探测高度和数据准确率等方面对雷达探测性能进行了统计分析。结果表明：增程型L波段风廓线雷达满足设计指标要求，可用于低对流层大气风场的观测。

THAAD增程型拦截弹预测制导方法

根据公开资料对THAAD增程型拦截弹建模,针对大射程的特点规划了高抛弹道,生成标准弹道族。提出了迭代预测命中点法,利用解析方法计算剩余飞行时间,基于多项式拟合法寻找标准弹道,确定预测命中点,完成预测制导任务。将迭代预测命中点法与迭代飞行时间法进行对比,迭代预测命中点法初值选取容易,程序运行时间减少20%,制导过程中无需调用标准弹道文件,节省了计算机存储空间。通过改变射程、航路捷径对预测制导方法进行仿真验证,结果表明,拦截弹拦截射程可覆盖到600 km,并且能完成存在航路捷径时的拦截任务,平均脱靶量在200 m以内,应对气动不确定性的效果良好。

MBDA公司首次成功试射增程型马特反舰导弹

2018年11月9日,MBDA公司研发的增程型马特(Marte ER)反舰导弹在意大利的靶场首次试射成功,完成重要里程碑节点。马特导弹按照预定弹道飞行超过100 km,包括几个航路点和掠海飞行,所有飞行阶段均测试成功。MBDA意大利公司总经理称,此次测试进一步验证了马特系列多平台反舰导弹增程型的稳定性。卡塔尔埃米尔空军于2018年早些时候订购了增程型马特导弹,用于装备新的NH90直升机。

GPS处理器增加炮弹精度

Ｉｎｔｅｒｓｔａｔｅ电子公司已研制成功将ＧＰＳ的惯导技术集成在一起的小型系统，以增加美国海军和陆军炮火的精度。该系统安置在一个线路板上，该线路板很小，能够安装到炮弹的鼻锥内。该线路板本来仅能处理ＧＰＳ数据，但Ｉｎｔｅｒｓｔａｔｅ电子公司的方案使用一个...

Method of closed loop springback compensation for incremental sheet forming process

The closed loop control model was built up for compensating the springback and enhancing the work piece precision.A coupled closed loop algorithm and a finite element method were developed to simulate and correct the springback of incremental sheet forming.A three-dimensional finite element model was established for simulation of springback in incremental sheet forming process.The closed loop algorithm of trajectory profile for the incremental sheet forming based on the wavelet transform combined with fast Fourier transform was constructed.The profile of processing tool path of shallow dishing with spherical surface was designed on the basis of the profile correction algorithm.The result shows that the algorithm can predict an ideal profile of processing track,and the springback error of incremental sheet forming is eliminated effectively.It has good convergence efficiency,and can improve the workpiece dimensional accuracy greatly.

A Property of Solutions for Elliptic Equation with Nonstandard Growth Conditions in Unbounded Domain

In this paper the author proves that the Phragmen Lindelof principle holds for solutions of elliptic equation (1) with nonstandard growth conditions.

Stochastic differential equation software reliability growth model with change-point

This paper presents software reliability growth models(SRGMs) with change-point based on the stochastic differential equation(SDE).Although SRGMs based on SDE have been developed in a large scale software system,considering the variation of failure distribution in the existing models during testing time is limited.These SDE SRGMs assume that failures have the same distribution.However,in practice,the fault detection rate can be affected by some factors and may be changed at certain point as time proceeds.With respect to this issue,in this paper,SDE SRGMs with changepoint are proposed to precisely reflect the variations of the failure distribution.A real data set is used to evaluate the new models.The experimental results show that the proposed models have a fairly accurate prediction capability.

An Unsteady Heterogeneous Mass Transfer Model for Gas Absorption Enhanced by Dispersed Third Phase Droplets

A model for one-dimensional unsteady heterogeneous mass transfer was developed based on Danck-werts' surface renewal theory in order to describe the mass transfer enhancement of absorption process for a slightly soluble gas in a gas-liquid-liquid system.The model accounts for the mass transfer resistance within the dispersed phase and the effect of emulsion viscosity on mass transfer.An analytical solution for enhancement factor was obtained by Laplace domain transformation.The absorption rates of carbon dioxide in the dodecane-in-water and castor oil-in-water systems were measured in a thermostatic reactor,and the enhancement factors were calculated at different volume fractions of dispersed phase and stirrer speeds.The model predictions agree well with the experimental data.

Secondary settlement estimation in surcharge preload subject to time effect of secondary consolidation coefficient

In order to eliminate the settlement underestimation in surcharge preload engineering, a study based on Bjerrum's creep diagram and the tangent slope definition of secondary consolidation coefficient was carried out to analyze the time effect of secondary consolidation coefficient of over consolidated soil, and a time–growth model for it was formulated. As Bjerrum's creep diagram is an idealized model, oedometer tests were performed to improve the above time–growth model of secondary consolidation coefficient for the purpose of achieving a better agreement with the actual ground situations. It is found that secondary consolidation coefficient of over consolidated soil not only decreases with the ratio of historical maximum to current effective stress of soil(OCR), but also increases with the development time of secondary consolidation. No matter how large OCR is, the long-term time effect of secondary consolidation coefficient of over consolidated soil is all significant. Based on the above results, a model for settlement estimation was formulated and a case study to estimate it indicates that the settlement estimated by our method is 2–5 times larger than that estimated by the previous method. Moreover, the larger the OCR is as well as the longer the service life is, the larger the difference between our method and the previous method is. Thus, the post-construction secondary settlement in surcharge preload engineering will be underestimated when neglecting the time effect of secondary consolidation coefficient in over consolidated state.

Characterization of promoters in Escherichia coli and application for xylitol synthesis

Promoters are the most important tools to control and regulate the gene expression in synthetic biology and metabolic engineering. The expression of target genes in Escherichia coli is usually controlled by the high-strength inducible promoter with the result that the abnormally high transcription of these genes creates excessive metabolic load on the host, which decreases product formation. The constitutive expression systems are capable of avoiding these defects. In this study, to enrich the application of constitutive promoters in metabolic engineering, four promoters from the glycolytic pathway of E. coli were cloned and characterized using the enhanced green fluorescent protein as reporter. Among these promoters, Pgap Awas determined as the strongest one, the strength of which was about 8.92% of that of the widely used inducible promoter PT7. This promoter was used to control the expression of heterologous xylose reductase in E. coli for xylitol synthesis so as to verify its function in pathway engineering. The maximum xylitol titer(40.6 g·L-1) produced by engineered E. coli under the control of the constitutive promoter Pgap Awas obviously higher than that under the control of the inducible promoter PT7,indicating the feasibility and superiority of promoter Pgap Ain the metabolic engineering of E. coli.

Synergy Model of Artificial Intelligence and Augmented Reality in the Processes of Exploitation of Energy Systems

The article presents a fragment of research and development, which objective was to develop technical tools and methodology to improve exploitation processes of energy systems. The author＇s model includes synergy of artificial intelligence and augmented reality. This solution, which combines modem technologies in order to improve the activities related to the continuity of energy supply, and reduce costs associated with the time needed to carry out exploitation activities and employment of qualified staff, is presented. This paper presents both theoretical foundations as well as the development of technical systems. The characteristics of exploitation processes of energy systems and possible technical conditions, as well as factors characterizing them, are discussed. The physical and software structures of the system and individual modules, as well as dependencies connecting them are demonstrated. The dependencies between physical and logical elements during the exploitation processes of energy systems, that determine decisions related to the evaluation of technical states and related activities are described. The advantages and limitations of the developed model which connects methods of data processing and analysis, interactive visualization processes and possible areas of application are as well discussed in detailed.

The Influence of Steel and Basalt Fibers on the Shear and Flexural Capacity of Reinforced Concrete Beams

To improve the shear and flexural capacity of flexural members, the steel and basalt fibers were used in model beams tested under flexure. Three series of single span free supported model beams were prepared from SFRC （steel fiber reinforced concrete） with longitudinal steel reinforcement （steel ratio of 1.2 %） and varied spacing of steel stirrups and they were tested till failure. Another three series of BFRC （basalt fiber reinforced concrete） double-span model beams with a span of 2 mm~ 1,000 mm and cross section 180 mm ~ 80 mm were tested. During the tests till to the failure the beam reactions, vertical deflections and horizontal strains in concrete were registered, to clarify the range of redistribution of bending moments and shear forces over the span of the beams. Almost all the tested model beams failed in shear, showing visible influence of steel and basalt fibers on the shear capacity of the tested beams. The tests results confirmed that steel and basalt fibers in reinforced concrete beams can partially replace （in certain cases） the traditional steel stirrups calculated for shear.

美国改进“陶”式导弹

美国雷声公司即将对“陶”2B增程型导弹进行定型试验,并将于2003年12月签订生产合同,2004～2009年生产。该型导弹的弹头改为尖拱形,射程增加到4500m。美国陆军还将把约500枚“陶”式导弹改进成“建筑结构破坏者”

Extracting predictable components and forecasting techniques in extended-range numerical weather prediction

This paper refers to the CNOP-related algorithms and formulates the practical method and forecast techniques of extracting predictable components in a numerical model for predictable components on extended-range scales.Model variables are divided into predictable components and unpredictable chaotic components from the angle of model prediction error growth.The predictable components are defined as those with a slow error growth at a given range.A targeted numerical model for predictable components is established based on the operational dynamical extended-range forecast(DERF)model of the National Climate Center.At the same time,useful information in historical data are combined to find the fields for predictable components in the numerical model that are similar to those for the predictable components in historical data,reducing the variable dimensions in a similar judgment process and further correcting prediction errors of predictable components.Historical data is used to obtain the expected value and variance of the chaotic components through the ensemble forecast method.The numerical experiment results show that this method can effectively improve the forecast skill of the atmospheric circulation field in the 10–30 days extended-range numerical model and has good prospects for operational applications.