A Radar System for Measuring the Wave-Forming Properties of Ships

A measuring system which uses a shore-based radar station and standard computers is considered. It is shown that, using semiexperimental computer modeling, the accuracy of the radar measuring system is quite acceptable for estimating the wave-forming properties of ships.Translated from Izmeritel’naya Tekhnika, No. 3, pp. 46–48, March, 2005.     

An Aerological Radar as a Means of Measurement

Metrological characteristics are presented for the Briz aerological radar. The physical quantities measured by the station are identified together with the transformation of the data during processing, as well as general aspects of assigning such stations as means of measurement.     

Raising the Accuracy of a Panoramic Monopulse Radar

A method is considered for raising the accuracy and noise immunity of a panoramic angular Doppler pulse radar by means of coherent signal processing between periods for frequency modulation unknown a priori. The method gives an algorithm simple to implement and applicable in digital primary processing.     

舵片增程的空气动力学仿真研究

研究了增程弹丸气动布局对弹道增程效果的影响,主要是针对弹丸有无舵片以及安装舵片的位置两种情况分析,建立对应的弹体模型,并对其进行气动仿真,得出相应的升力系数和阻力系数,并计算出升阻比,进而判断有无舵片以及舵片的安装位置对弹道增程效果的影响.仿真结果表明:有舵片相对无舵片的弹丸增程效果明显,升阻比最多增加25.17%,最少增加0.49%;舵片安装位置不同,其增程效果也存在明显差异,并且升阻比在距离弹头90 mm时增加最为明显.因此认为在满足全弹气动布局、飞行稳定的基础上,在弹丸适当位置安装舵片并相应改变攻角,可有效增加弹丸射程.     

气泡辅助航行系统降低船模-碎冰相互碰撞的试验研究

通过模型试验探究气泡辅助系统降低船舶与碎冰相互碰撞的机理,依托"雪龙2"号船模设计了气泡辅助航行系统,在哈尔滨工程大学室外冰水池内进行了非冻结模型冰碎冰航道的船模拖航试验。通过机理试验,探究气泡辅助航行系统使用前后船模与浮冰相互作用模式的差异,同时根据船艏、船舯的浮冰清除效果,分析该系统对这两部分浮冰碰撞作用的减轻程度;随后改变试验参数,探究航速、喷气量以及浮冰密集度对该系统工作效果的影响,进一步探究该气泡辅助系统的工作机理。     

螺旋桨轴向激励潜艇的轴、艇耦合特性与机理

潜艇轴系向艇体传递激振力的过程是轴、艇耦合作用过程,为解决工程中需采用简化等效轴-艇模型进行轴、艇激振力传递分析的问题,针对潜艇模型进行了螺旋桨轴向激振力工况下的轴、艇耦合特性与机理研究:在不改变耦合状态的情况下,采取子系统分析方法,将轴-艇耦合系统分解为轴系子系统和艇体子系统,利用力模式分解技术研究了轴系向艇体传递激振力的模式,研究了轴、艇耦合状态,采取子模态分析技术分析了艇体自由模态与轴系的耦合关系。数值研究结果表明:轴系对激振力的传递具有多模式特征,各轴承对激振力传递的贡献程度由激振频段决定,不同激振频段的轴、艇耦合强度不同,参与轴、艇强耦合的艇体模态数量和类型也不同。相关定量结果可为工程中轴-艇模型化分析提供技术支撑。     

Analysis of the characteristics of a system for digital recording of optical signals based on an array photodetector

An experimental investigation of the characteristics of an optoelectronic digital image recording system based on a charge-coupled photosensitive device is performed. The influence of the operating modes of the system on the statistical characteristics of its two-dimensional output signals is evaluated. A technique for estimating the resolution of the recording system and the measurement error of the displacement of an element of the image by means of optical target rods is developed. Translated from Izmeritel’naya Tekhnika, No. 4, pp. 29–33, April, 2009.     

基于神经网络技术的南京长江大桥桥墩船舶撞击力识别

主要研究基于神经网络技术的南京长江大桥桥墩船撞力识别。在建立了南京桥4#桥墩的空间有限元分析模型后,对4#桥墩进行了动力特性分析;基于MATLAB平台建立了“船撞力-响应”神经网络,由沃辛试验船撞力曲线计算得到了船对桥墩的撞击响应并作为神经网络训练的样本。仿真计算结果表明,由桥墩墩顶的响应可有效识别船舶撞击力的大小、方向和撞击位置,该神经网络可用于有、无噪声干扰的船撞力识别,并且具有良好的容错性和鲁棒性。     

邛崃市某酒店冷热源设计方案比较

根据邛崃市某酒店的能耗计算结果,比较了带热回收主机的系统和无热回收主机的系统。根据比较分析的结果,发现采用无热回收主机的系统为该酒店优选方案。     

Algorithms for the Optimum Estimation of the Parameters of a Radio Signal in a Measurement Time of Less Than a Period and a Nonmultiple of a Period in Which the Result Is Tied to the Beginning of the Measurement Interval

Optimum estimates of the parameters of a noisy (white noise) sinusoidal radio signal of known frequency are considered, based on an investigation of the likelihood function, when the measurement time is less than a period and a nonmultiple of a period. Estimates are presented for the phase shift and the amplitude in the presence (absence) of a constant component and nonlinear distortions when the result is tied to the beginning of the measurement interval.     

Measurement and Identification of the Parameters of SPICE-Models of a Bipolar Transistor

A method of measuring and identifying the static parameters of a bipolar transistor is considered. The characteristic of the transistor, from which the parameters of the model are determined, is chosen depending on what group the calculated parameters belong to. The characteristics are measured in such a way that the equations of the model describing them can be reduced to the simplest form.     

On the electro-osmotic flow in a saturated porous medium

Electro-osmosis in a saturated porous rigid medium is studied by both theoretical and experimental approach. Relationships giving liquid and electrical coupled macroscopic flows are obtained from the homogeneization method. They point out possible non symmetrical cross effects that explain deviations from Onsager reciprocal relations. Experiments on a kaolinite are reported which exhibit an important non symmetrical coupling.     

Modeling of the state of individual parts of a complex biosystem when there are stresses and strains

A method of investigating the stresses in solid and dynamically loaded models, which are prototypes of individual components of a complex biosystem, is proposed. The method enables the experiment to be simplified considerably and considerably reduces the time required. __________ Translated from Metrologiya, No. 1, pp. 29–37, January, 2007.     

Optimization of the underwater structures employed when calibrating hydrophones in a free field

The results of investigations of the distribution of sources of reflections on the bars employed to position hydrophones under water during free-field measurements are analyzed. It is established experimentally that the sources of reflections are formed on parts of the bars where its reflective power changes sharply. It is shown that structures, designed taking into account the mechanism of the distribution of sources of reflection, enable the interference distortions of the acoustic field to be reduced considerably. __________ Translated from Izmeritel’naya Tekhnika, No. 1, pp. 60–63, January, 2007.     

Numerical Simulation of the Dynamics of Elastic Tubular Spirals with Internal Inhomogeneous Flows of a Boiling Liquid

We pose a problem of numerical investigation of the dynamic behavior of a spiral tube with internal inhomogeneous flows of a boiling liquid and propose a model of motion of contracting clusters of heated liquid separated by cavities filled with steam. For the considered dynamical system with variable geometry of masses, we construct a system of differential equations with time-dependent discontinuous coefficients on the right-hand side. We describe a method for their numerical solution based on the use of methods of numerical integration with respect to time and the method of initial parameters together with a procedure of orthogonalization with respect to the spatial variable. We study vibrations in the system for various parameters of inhomogeneity of the flow, its velocity, and the parameter of dissipation of energy. It is shown that both stable and unstable modes of motion can be realized depending on the character of inhomogeneities and the velocity of motion of liquid clusters.     

Inverse problem of thermoelasticity for the isotropic medium containing a cavity in the case of triaxial tension with constant temperature on the surface

We consider the inverse problem of thermoelasticity for an isotropic medium containing a cavity of unknown shape and subjected to the action of mechanical and thermal loads. Nonlinear equations are deduced for the geometric parameters of an ellipsoidal equistressed cavity. Similar relations for mechanical loads obtained by the other authors follow from the constructed equations as special cases. The numerical analysis is performed and the relationship between the values of the loads and the parameters of the cavity is investigated. The stresses on the equistressed surface of the cavity are found and the influence of temperature on the relationship between the parameters of loads and the geometric characteristics of the equistressed cavity is analyzed. __________ Translated from Problemy Prochnosti, No. 1, pp. 121–131, January–February, 2007.     

Investigation of the error in transferring the dimensions of the volt using a transportable stabilitron voltage standard

The results of an investigation of the characteristics of transportable voltage standards based on stabilitrons for the purpose of using them as standards of comparison when transferring the dimension of the unit of constant voltage in accordance with the State Standard GOST 8.027-2001 are presented. It is shown that, using the standard investigated, one can transfer the dimensions of the unit of voltage with an overall relative error of 5·10⁻⁸ for a voltage of both 1.018 V and 10 V. __________ Translated from Izmeritel'naya Tekhnika, No. 1, pp. 34–38, January, 2006.     

An autonomous estimate of the rate of change of the error of a radio-electronic measuring instrument

An autonomous experimental estimate of the limits of possible values of the rate of change of the error of measuring instruments with time is given. __________ Translated from Izmeritel’naya Tekhnika, No. 5, pp. 41–42, May, 2008.     

A Detector of the Angular Position of the Guide Vanes of a Compressor

The problems of designing a detector of the angular position of the guide vanes of a compressor, the accuracy of the positioning of which ensures the optimum operation of a gas turbine engine, are considered.     

Measurement of the Frequency of a Harmonic Signal,Received on a Background of Additive White Noise,from a Short Sample

The noise immunity of a method of measuring frequency, based on comparing the form of the signal spectrum in a Fourier basis with a set of standard spectra, using computer modeling is presented.