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在初二学生学过液体的静压强之后,补充一个利用 U 形管连通器测定不溶混液体密度的实验,对于学生掌握液体静压强的概念和连通器原理,以及进一步理解密度的概念,很有好处。兹介绍如下。 相似文献
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测量物质密度的常规方法有:一是对规则固体而言,用测长工具测体积,用天平称质量,再根据密度的定义求得;二是对不规则的固体用流体静力法进行测量,流体静力法对液体的密度测量同样适用;三是用比重瓶法测液体和固体的密度.而根据液体内部压强特点利用U型连通器或W型连通器测液体的密度和根据浮力的原理利用悬浮法测固体的密度的方法则不多见,而这种构思新颖、设计巧妙的方法能解决一些特殊物质的密度的测量.下面详细介绍这两种测密度的方法. 相似文献
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例说与连通器相关的功和能的问题 总被引:1,自引:1,他引:0
连通器问题是我们在实际中经常碰到又比较难的问题,笔者认为主要是抓住几个关键点:其一、属不属于连通器模型;其二、抓住液体体积不变;其三、大气对研究的系统做功代数和为零;其四、善于利用液体等效体积的方法来处理问题.下面通过几个例题来讨论说明. 相似文献
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文献[1]于连通器中开拓出一些有关功能问题的新视角,颇具启发性和教学参考意义.笔者不禁不揣浅陋,略续狗尾些许,以就教于作者及诸同仁. 相似文献
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介绍了用恒流法自制仪器精确测定液体的黏度.该自制仪器,能有效地保证底部的密封性、液体水位恒定和可操作性.另外,还增设一个玻璃管连通器,并附加一根标尺和游标,可使液体水位的测量精确度提高.在接毛细管输出液体的量筒处加上光电计时,可使测量液体的流速的精确度提高.再将相关数据送入已编好程序的电子仪器进行计算并显示出黏度.另外该仪器可调换不同管径的毛细管,因此应用本方法能快速准确地测量多种液体的黏度. 相似文献
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在研究连通器平衡问题时,通常利用公共等压面列出方程组来求解。用这种方法来求解问题比较繁琐,如下面这个问题:组合式水银测压计,忽略气柱重量,求A点压强(图1)。 相似文献
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针对教材中测量液体和空气浮力实验中存在的问题,做了相应的改进.首先,改进了探究液体浮力的实验装置,采用体积较大的物体作为研究对象,利用铁架台固定弹簧秤,并通过连通器注入液体,实现了稳定清晰地观测液体浮力现象.其次,设计了探究气体浮力的实验装置,收集VC泡腾片与水反应产生的气体,并充入气球,由于气球受到浮力导致杠杆变化,进而可以明显观察到气体的浮力现象. 相似文献
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采用系统中的局部不均匀性消除振荡系统中的反螺旋波. 该不均匀性在系统中成为一个波源,不断产生稳定的相波. 研究结果发现,不均匀性的尺寸大小存在一个临界值,如果低于此临界值,则系统将无法激发任何相波. 根据不均匀性形状的不同,系统分别产生靶波和行波. 此外,实验还发现靶波与反螺旋波之间以及行波与反螺旋波之间存在着不同的动态竞争. 数值计算表明,对于行波,无论是低频行波还是高频行波,都可以成功地消除系统中的反螺旋波;而对于靶波,只有低频靶波才可以消除反螺旋波. 此控制方法简单易行,且同样适用于消除向外传播的螺旋波 相似文献
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We investigate surface waves at the interface between a metal and a photovoltaic-photorefractive (PP) crystal. These surface waves appear in several forms: delocalized surface waves, shock surface waves, and localized surface waves. Only localized surface waves have limited energy. We demonstrate that the transverse sizes of localized surface waves decrease with an increase in the propagation constant and the amplitudes of localized surface waves increase with the propagation constant. The stability of localized surface waves is investigated numerically and it is found that they are stable. 相似文献
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Guided waves propagating in cylindrical tubes are frequently applied for the characterization of material or geometrical properties of tubes. In a tube, guided waves can propagate in the axial direction and called axial guided waves, or in the circumferential direction called circumferential guided waves. Dispersion spectra for the axial and circumferential guided waves share some common behaviors and however exhibit some particular behaviors of their own. This study provides an investigation with theoretical modeling, experimental measurements, and a simplex-based inversion procedure to explore the similarity and difference between the axial guided waves and circumferential guided waves, aiming at providing useful information while axial and circumferential guided waves are applied in the area of material characterization. The sensitivity to the radius curvature for the circumferential guided waves dispersion spectra is a major point that makes circumferential guided waves different from axial guided waves. For the purpose of material characterization, both axial and circumferential guided waves are able to extract an elastic moduli and wall-thickness information from the dispersion spectra, however, radius information can only be extracted from the circumferential guided waves spectra. 相似文献
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Szwerc RP Burroughs CB Hambric SA McDevitt TE 《The Journal of the Acoustical Society of America》2000,107(6):3186-3195
In complex structures, curvature and impedance discontinuities (e.g., junctions) couple bending and longitudinal waves. Propagation losses for longitudinal waves are often much less than losses for bending waves, and damping treatments often less effective on longitudinal waves. When the dissipation in longitudinal waves is less than that on bending waves, longitudinal waves can provide an efficient means of power flow between bending waves generated at one location and bending waves that are a source of acoustic radiation at another location. In order to design and locate effective treatments, knowledge of the power flow in longitudinal as well as bending waves is required. The measurement of power in both bending and longitudinal waves when both waves are present is demonstrated. Measurements conducted on a straight beam and a T-beam are compared to predictions obtained using finite element methods. The effect of coupling between waves at the junction in a T-beam is illustrated using results from measurements of power flow. 相似文献
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利用基本电子元器件和常用普通芯片设计出能产生频率可调方波、三角波、正弦波信号的电路;并制作出PCB板,制成实物供"示波器使用"实验使用,即方便了教学,又节约了经费。 相似文献
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To study the electromagnetic (EM) backscatter
characteristics of freak waves at moderate incidence angles, we
establish an EM backscattering model for freak waves in
(1+1)-dimensional deep water. The nonlinear interaction between
freak waves and Bragg short waves is considered to be the basic
hydrodynamic spectra modulation mechanism in the model. Numerical
results suggest that the EM backscattering intensities of freak
waves are less than those from the background sea surface at
moderate incidence angles. The normalised radar cross sections
(NRCSs) from freak waves are highly polarisation dependent, even at
low incidence angles, which is different from the situation for
normal sea waves; moreover, the NRCS of freak waves is more
polarisation dependent than the background sea surface. NRCS
discrepancies between freak waves and the background sea surface
with using horizontal transmitting horizomtal (HH) polarisation are
larger than those with using vertical transmitting vertical (VV)
polarisation, at moderate incident angles. NRCS discrepancies
between freak waves and background sea surface decreases with the
increase of incidence angle, in both HH and VV polarisation radars.
As an application, in the synthetic-aperture radar (SAR) imaging of
freak waves, we suggest that freak waves should have extremely low
backscatter NRCSs for the freak wave facet with the strongest slope.
Compared with the background sea surface, the freak waves should be
darker in HH polarisation echo images than in VV echo images, in SAR
images. Freak waves can be more easily detected from the background
sea surface in HH polarisation images than in VV polarisation
images. The possibility of detection of freak waves at low incidence
angles is much higher than at high incidence angles. 相似文献
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From the beginning of the 20th century, researchers have been interested in surface electromagnetic waves guided by planar interfaces of dissimilar mediums. Much initial research on surface‐plasmon waves and surface‐plasmon‐polariton waves stemmed from theoretical curiosity, but the development of new experimental techniques propelled commercial exploitation for optical sensors of chemical and biological species. Additional surface waves called Dyakonov waves, Tamm waves, and Dyakonov–Tamm waves have emerged during the last 25 years. Experimental observation of Dyakonov waves was reported only in 2009, but the rapid development of experimental apparatus during the 1990s suggests that theoretical predictions will soon be evaluated experimentally, leading to further development of optical detection systems and optical circuitry. 相似文献
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We investigate a (2+1)-dimensional shallow water wave equation and describe its nonlinear dynamical behaviors in physics. Based on the N-soliton solutions, the higher-order fissionable and fusionable waves, fissionable or fusionable waves mixed with soliton molecular and breather waves can be obtained by various constraints of special parameters. At the same time, by the long wave limit method, the interaction waves between fissionable or fusionable waves with higher-order lumps are acquired. Combined with the dynamic figures of the waves, the properties of the solution are deeply studied to reveal the physical significance of the waves. 相似文献
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We give a brief review on the recent development of gravitational waves in extra-dimensional theories of gravity. Studying extra-dimensional theories with gravitational waves provides a new way to constrain extra dimensions. After a flash look at the history of gravitational waves and a brief introduction to several major extra-dimensional theories, we focus on the sources and spectra of gravitational waves in extra-dimensional theories. It is shown that one can impose limits on the size of extra dimensions and the curvature of the universe by researching the propagations of gravitational waves and the corresponding electromagnetic waves. Since gravitational waves can propagate throughout the bulk, how the amplitude of gravitational waves decreases determines the number of extra dimensions for some models. In addition, we also briefly present some other characteristics of gravitational waves in extra-dimensional theories. 相似文献