Devices and Methods of Measurements最新文献

{"title":"Device and Measuring Method the Moments of Rolling Resistance Forces on the Contact Spot","authors":"И. З. Джилавдари, С. Мекид, Н. Н. Ризноокая","doi":"10.21122/2220-9506-2019-10-4-308-321","DOIUrl":"https://doi.org/10.21122/2220-9506-2019-10-4-308-321","url":null,"abstract":"Currently, the study of rolling friction is one of the main directions in the study of the laws of contact interaction of solids. The complexity of solving the problems existing in this area is evidenced by the practically vast number of publications, the list of which is constantly growing.In this paper, attention is paid to studies of the moments of rolling resistance at displacements from the equilibrium position of a ball-shaped body that are substantially smaller than the size of the contact spot. The purpose of the present work is to describe the design of the single-contact pendulum device developed by the authors, in which the physical pendulum, resting on the flat surface of the body under study with only one ball, makes free small stable swings in a vertical plane, as well as in the description of a special measurement technique with high sensitivity and accuracy rolling resistance forces, including adhesion forces and frequency-independent forces of elastic deformations. It is assumed that the adhesion forces can exhibit both dissipative properties and elastic properties, while elastic forces are independent of the strain rate.The originality of the method of measuring rolling resistance in this paper consists in using the method of nonlinear approximation of the dependence of the amplitude and period of swing of the pendulum on time. The approximation is carried out on the basis of the proposed laws of amplitude decay and period variation, which differ from the usual exponential law.It is assumed that this approach allows one to evaluate the surface tension of a solid and evaluate the pressure of adhesion forces between the surfaces of the contacting bodies, as well as to establish an analytical form of the moment of rolling resistance. The curves of the dependence of the rolling resistance moment on the swing amplitude of the pendulum are constructed. Experiments were performed for the following pairs of contacting bodies: steel-steel, steel-glass, steel-electritechnical silicon. It was assumed that the pressure at the contact spot did not exceed the elastic limit.The developed single-ball pendulum device and the proposed measurement procedure open up new wide possibilities for studying the laws of mechanisms of rolling resistance under conditions of microand mesoscale displacements of a rolling body from a state of rest.","PeriodicalId":41798,"journal":{"name":"Devices and Methods of Measurements","volume":"143 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2019-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90440994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Controlling of Differential Resistance of p–n-Junctions of Bipolar Transistor in Active Mode by Method of Impedance Spectroscopy","authors":"N. Gorbachuk, N. Poklonski, Ya. N. Marochkina, S. V. Shpakovski","doi":"10.21122/2220-9506-2019-10-3-253-262","DOIUrl":"https://doi.org/10.21122/2220-9506-2019-10-3-253-262","url":null,"abstract":"Controlling of parameters of manufactured transistors and interoperational controlling during their production are necessary conditions for production of competitive products of electronic industry. Traditionally for controlling of bipolar transistors the direct current measurements and registration of capacity-voltage characteristics are used. Carrying out measurements on alternating current in a wide interval of frequencies (20 Hz–30 MHz) will allow to obtain additional information on parameters of bipolar transistors. The purpose of the work is to show the possibilities of the method of impedance spectroscopy for controlling of differential resistance of p–n-junctions of the bipolar p–n–p-transistor in active mode.The KT814G p–n–p-transistor manufactured by JSC “INTEGRAL” was studied by the method of impedance spectroscopy. The values of differential electrical resistance and capacitance for base–emitter and base–collector p–n-junctions are defi at direct currents in base from 0.8 to 46 µA.The results of the work can be applied to elaboration of techniques of fi checking of discrete bipolar semiconductor devices.","PeriodicalId":41798,"journal":{"name":"Devices and Methods of Measurements","volume":"81 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2019-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73017223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of an out-of-Focus Irradiator Based on a Phased Antenna Array for a Space Communications' Parabolic Reflector Antenna","authors":"D. V. Douksha, S. Liashkevich, V. Saetchnikov","doi":"10.21122/2220-9506-2019-10-3-233-242","DOIUrl":"https://doi.org/10.21122/2220-9506-2019-10-3-233-242","url":null,"abstract":"Mirror antenna systems are widely used in satellite and space communication systems and radio astronomy. Development of these areas requires new efficient antenna systems' design. Possible technical solution for creating an effective mirror antenna is a “hybrid” scheme, when an adaptive phased antenna array is used as an irradiator. This paper is devoted to the development of an out-of-focus irradiator based on a phased antenna array for a space communications' parabolic reflector antenna. The aim of the work is to develop an optimal design of the irradiator with the choice of the structural element of the antenna array and experimental studies of the selected structural element.The wavefront recovery method was used as a tool for selecting the irradiator configuration. The idea of this method use is to reproduce the electromagnetic field of an incident plane wave with an irradiator in order to uniformly illuminate the aperture of the antenna mirror.In order to select the structural element of the irradiator several antennas were considered: a patch antenna, a flat spiral antenna, a conical spiral antenna. The requirements for the phased antenna array element were defined. The irradiator based on the above mentioned was simulated and the irradiator geometry was optimized according to the maximum gain criterion.The maximum gain was achieved for the irradiator based on conical spiral antennas and amounted to 30.8 dB, which for the considered mirror aperture of 2.4 m is close to traditional focal schemes. The results obtained make it possible to create an adaptive antenna system able to compensate for the deviations of the mirror's shape from the theoretical profile, as well as phase distortions in the atmosphere by changing the lattice weights coefficients.","PeriodicalId":41798,"journal":{"name":"Devices and Methods of Measurements","volume":"24 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2019-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84686866","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Measurements of the Hydrodynamic and Vibrational Characteristics to Validate Numerical Calculations of the Structure Excitation by Fluid Flow","authors":"A. Budnikov, E. Shmelev, D. Kulikov, A. V. Loginov, S. Dmitriev, N. Pribaturin, P. Lobanov, A. Suvorov, A. V. Stulenkov","doi":"10.21122/2220-9506-2019-10-3-223-232","DOIUrl":"https://doi.org/10.21122/2220-9506-2019-10-3-223-232","url":null,"abstract":"Structure vibration under the influence of unsteady hydrodynamic forces caused by the flow around their surfaces can adversely affect durability and rupture life. Reducing the adverse effects of hydrodynamic forces is currently possible with the help of linked CFD and vibration calculations. However, for an adequate description of the associated processes one should use calculation models and approaches specific to the hydro-vibration problem. To justify and validate such approaches, an experimental model was developed and a series of structure excitation tests in water flow was carried out.The model comprises two cylinders installed sequentially in water crossflow. Vibration levels, pressure and velocity fluctuations were measured in the tests as a functions of the flow velocity. The application of different non-intrusive measurement techniques was possible due to relatively simple test model construction which may be used for cross-validation and experimental uncertainty quantification.Flow-structure interaction, caused by synchronization effect of the flow separation frequency (or it’s spectral components) and eigenfrequency of cylinder, was analyzed based on simultaneously measured data. The tests performed gave the information about dynamical characteristics of the flow and vibration parameters of cantilevered cylinders. The experimental results are used for identification of required accuracy of hydrodynamic forces calculation by CFD and validation of oneand two-way linked methods for flow excitation frequency calculation.","PeriodicalId":41798,"journal":{"name":"Devices and Methods of Measurements","volume":"80 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2019-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91286622","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Digitalization of Spectral Measurements in the Fourier Basis – Development Trends and Problems","authors":"O. Ponomareva, A. Ponomarev, N. V. Smirnova","doi":"10.21122/2220-9506-2019-10-3-271-280","DOIUrl":"https://doi.org/10.21122/2220-9506-2019-10-3-271-280","url":null,"abstract":"At the present stage of development of digital information technologies intensive digitalization (computerization) of both direct and indirect measurement methods is taking place. The direct consequence of the computerization of measurements was, firstly, the emergence of a new class of measuring instruments – Processor measuring instruments (PRIS), secondly, increasing the level of formalization of measuring procedures, thirdly, the creation of a new, revolutionary technology –Virtual Instrument (VI). The purpose of the article is to analyze the development of digital technologies for measuring spectra, identifying the problems that arise in this case and formulating priority scientific and applied problems for their resolution.Theoretical and applied research has established that digital spectrum measurement technologies, in addition to significant advantages, have certain disadvantages. It has been shown that the disadvantages of digital technologies for measuring spectra arise both from the nature of digital methods and from the analytical and stochastic properties of the bases of the applied transformations in measuring the spectra. An analysis of digital methods for measuring spectra showed that methods based on Discrete Fourier Transform (DFT) retain their leading role and are effective in almost all subject areas. However, there are also problems of digitalization of measurements of the spectra of signals based on the DFT, which are associated, first of all, with the manifestation of a number of negative effects that are absent with analog methods for measuring spectra based on the Fourier transform. This is the periodization effect of the measuring signal and its spectrum, the stockade effect, as well as the aliasing effect. As the analysis showed, existing methods of dealing with the negative effects of digitalization of spectrum measurements solve the problems of introducing digital technologies only partially. To combat the negative effects of digitalization of spectral measurements, a generalization of the DFT in the form of a parametric DFT (DFT-P) (Parametric Discrete Fourier Transform – DFT-P) is proposed.The main scientific and applied problems of computerization of signal spectrum measurements are formulated: the development of the theory of digital methods for measuring signal spectra, the creation of new and improvement of existing digital methods for measuring signal spectra, the development of algorithmic, software and metrological software for PRIS and VI for the implementation of DFT-P.","PeriodicalId":41798,"journal":{"name":"Devices and Methods of Measurements","volume":"64 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2019-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90594707","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Application of Magnetic Noise Method to Control the Mechanical Anisotropy of Ferromagnetic Materials","authors":"V. Busko, A. A. Osipov","doi":"10.21122/2220-9506-2019-10-3-281-292","DOIUrl":"https://doi.org/10.21122/2220-9506-2019-10-3-281-292","url":null,"abstract":"Presence of anisotropy of the ferromagnetic materials' properties determines the need for its research and control, since it has a significant impact on the basic physicomechanical characteristics of details, products and constructions. The aim of the work was to experimentally investigate the possibility of using the magnetic noise method for non-destructive testing of mechanical properties of ferromagnetic materials particularly value of the coefficient of normal anisotropy Rn of sheet metal, mechanical stresses under elastic deformation of electrical steel and the anisotropy of the physical and mechanical properties of ferromagnetic materials.Since the mechanical anisotropy is related to the magnetic anisotropy, the magnetic method of the Barkhausen effect (MBE) was used in its study, the informative parameters of which belong to the group of magnetic anisotropy. Comparison of the results of anisotropy evaluation on a set of samples of stamped sheet steel using the MBE with values Rn measured by the manufacturer showed their close match. This revealed the possibility of Rn level evaluation using the MBE. Device for circular rotation of the Barkhausen transducer on the sample surface and device for forming of elastic bending stresses in the sample were constructed. To study the magnetic anisotropy in various materials and the impact of elastic tensile and compressive stresses by bending on it using the MBE.It has been found that the elastic deformation in samples of electrical steel leads to dramatic change of the magnetic noise level and the shape of the circular diagrams, taking into account the sign of the stresses generated in the sample. It was established that as a result of cold rolling in the production process, electrical steel samples have a pronounced texture due to the direction of rolled sheet. The created elastic stresses in the considered range practically do not change the texture (induced crystallographic anisotropy) after the material rolling.The results can be useful for studying, monitoring and testing of anisotropy, crystallographic texture, structural heterogeneity of ferromagnetic materials in the form of sheet metal, sheet steel and coil steel, sheet metal forming and for solving other problems using the magnetic noise method in aboratory and workshop conditions.","PeriodicalId":41798,"journal":{"name":"Devices and Methods of Measurements","volume":"11 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2019-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84170882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Research of Surface Wear Resistance of Aluminum Alloy Modified with Minerals using Sclerometry Method","authors":"A. Skazochkin, G. Bondarenko, P. Żukowski","doi":"10.21122/2220-9506-2019-10-3-263-270","DOIUrl":"https://doi.org/10.21122/2220-9506-2019-10-3-263-270","url":null,"abstract":"Improving the wear resistance of the surface of metal parts used in various industries is one of the relevant areas of materials science. The aim of this work was a comparative study of the wear resistance of a sample of an aluminum alloy (EN AW-2024, an aluminum alloy of the Al-Cu-Mg system) modified with ultrafine particles of minerals using the sclerometry method, which makes it possible to measure the physicomechanical properties of the material at the microscale, as well as determining some tribological parameters (hardness and elastic modulus) of a duralumin sample with a mineral coating.Wear resistance was measured using a NanoScan-4D scanning hardness tester using the multi-cycle friction method using a sapphire sphere with control of the pressing force and the deepening of the tip into the sample. The use of such a measurement system is especially important when testing thin modified layers, when the layer thickness is comparable with the surface roughness parameters and the influence of the substrate is excluded.The measurement results showed that the wear resistance of the surface of an aluminum alloy sample modified with ultrafine mineral particles increased by more than 12 times compared to the wear resistance of an aluminum alloy surface without modification. Also, measurements of the hardness and elastic modulus of the surface of the modified sample were performed taking into account the features of measuring the mechanical parameters of thin layers.The obtained parameters of the modified surface of the aluminum alloy can be further used to build models of the processes of friction and wear of the surface modified by ultrafine particles of minerals. The lack of an acceptable explanation of the nature of the special properties of the surface modified by particles of minerals of natural origin does not exclude the use of the observed effects to significantly increase the resource of various parts and mechanisms.","PeriodicalId":41798,"journal":{"name":"Devices and Methods of Measurements","volume":"1 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2019-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86088242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Measurements of Periodic Signals Phase Shifts with Application of Direct Digital Synthesis","authors":"I. Gula, O. Polikarovskykh, K. Horiashchenko, L. Karpova, V. Melnychuk","doi":"10.21122/2220-9506-2019-10-2-169-177","DOIUrl":"https://doi.org/10.21122/2220-9506-2019-10-2-169-177","url":null,"abstract":"The development of new methods and high-bit instruments for measuring phase shifts of high-frequency periodic signals with high speed for radar and radionavigation tasks is an actual task. The purpose of this work is to create a new phase shift meter for high-frequency periodic signals based on the double-matching method using direct digital frequency synthesis.On the basis of the proposed mathematical model of phase shift measurements of periodic signals by the method of double coincidence using the statistical accumulation of pulse coincidences, a functional diagram of a digital phase shift meter of periodic signals using a direct digital frequency synthesizer is developed. This allowed the implementation of an 8-bit converter phase shift signal to the code on the programmed logic integrated circuit EPM240T100C5N firm Altera.The digital phase shift meter of periodic signals based on the double-matching method consists of two comparators, two short-wave pulse generators, a direct digital frequency synthesizer, two pulse counter control circuits, two short pulse coincidence circuits, two pulse counting circuits, four clock counters, four registers, a microcontroller and an indicator. Block diagram of a double-matching digital phase meter using direct digital sintesizer use minimal hardware logic.In the developed phase shift meter, due to the use of the double-matching method, the time delay between signals does not depend on the period of input signals and can be found when changing the frequency of periodic pulses in wide limits. Measurement errors will be determined mainly by the duration of the pulses of coincidence. The use of statistical accumulation of pulse coincidence in the basis of the work allowed eliminating the restrictions on the duration of pulses of known non-ionic meters.On the basis of the obtained results, a high-bit converter of phase shifts of high-frequency periodic signals into a binary code with high speed for problems of industrial tomography, radar and radionavigation can be developed.","PeriodicalId":41798,"journal":{"name":"Devices and Methods of Measurements","volume":"36 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2019-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78009889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Angular Photometry of Biological Tissue by Ellipsoidal Reflector Method","authors":"M. Bezuglyi, N. Bezuglaya, A. V. Ventsuryk, Kostiantyn Vonsevych","doi":"10.21122/2220-9506-2019-10-2-160-168","DOIUrl":"https://doi.org/10.21122/2220-9506-2019-10-2-160-168","url":null,"abstract":"Angular measurements in optics of biological tissues are used for different applied spectroscopic task for roughness surface control, define of refractive index and for research of optical properties. Purpose of the research is investigation of the reflectance of biologic tissues by the ellipsoidal reflector method under the variable angle of the incident radiation.The research investigates functional features of improved photometry method by ellipsoidal reflectors. The photometric setup with mirror ellipsoid of revolution in reflected light was developed. Theoretical foundations of the design of an ellipsoidal reflector with a specific slot to ensure the input of laser radiation into the object area were presented. Analytical solution for calculating the angles range of incident radiation depending on the eccentricity and focal parameter of the ellipsoid are obtained. Also created the scheme of image processing at angular photometry by ellipsoidal reflector.The research represents results of experimental series for samples of muscle tissues at wavelengths 405 nm, 532 nm, 650 nm. During experiment there were received photometric images on the equipment with such parameters: laser beam incident angles range 12.5–62.5°, ellipsoidal reflector eccentricity 0.6, focal parameter 18 mm, slot width 8 mm.The nature of light scattering by muscle tissues at different wavelengths was represented by graphs for the collimated reflection area. The investigated method allows qualitative estimation of influence of internal or surface layers of biologic tissues optical properties on the light scattering under variable angles of incident radiation by the shape of zone of incident light.","PeriodicalId":41798,"journal":{"name":"Devices and Methods of Measurements","volume":"18 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2019-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82712737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Technique for Measuring the Internal Diameter and Area of Visible Vessels of the Eye","authors":"Владимир Александрович Фираго, Алексей Иванович Кубарко","doi":"10.21122/2220-9506-2019-10-2-185-197","DOIUrl":"https://doi.org/10.21122/2220-9506-2019-10-2-185-197","url":null,"abstract":"The study of the effects on the microvasculature of various vasoactive drugs requires appro-priate methods and equipment for determining the basic physiological parameters of small blood vessels: their internal diameter and cross-sectional area, specific density, and blood flow velocity. Therefore, the purpose of the article is to study the possibilities of improving the reliability of determining the internal diameter and cross-sectional area of the visible blood vessels of bulbar con-junctival of the eye.A technique for obtaining digital video recordings of the bulbar conjunctiva of the eye, based on the pulse illumination of the study area, is proposed. A prototype of the equipment with a spatial resolution of 2 µm video is described, which allows to trace all visible blood vessels, including capillaries. An algorithm for stabilizing the position of a sequence of digital images of the bulbar conjunctiva relative to the first frame is discussed. It is based on the use of subpixel interpolation when searching for a global minimum of the standard deviation of the differences in brightness of the first and selected frame.The proposed algorithms for tracing the vascular pattern and determining the internal diameter and cross-sectional area of the blood vessels are described. An original method for calculating them is proposed, which is based on determining the area and height of a cross section of a blood vessel image. The problem of verification of the obtained results is discussed.The described approach to make it possible to create diagnostic images of the visible blood vessels of the bulbar conjunctiva, including the capillaries, with an indication of their diameters. Examples of the construction of histograms of the distribution of the internal diameter and cross-sectional area of these blood vessels are presented.The proposed technique and hardware solutions have the prospect of being used in creating equipment for complex non-invasive diagnostics of the microvasculature and monitoring the effectiveness of treating various diseases of the cardiovascular system, since the conditions of the eye blood vessels correlate with the state of the blood vessels in other organs.","PeriodicalId":41798,"journal":{"name":"Devices and Methods of Measurements","volume":"12 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2019-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89959940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}