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1教学设计1.1教学思想本节包含牛顿第一定律和惯性两部分.教材内容较多,《课程标准》要求较高,而学生的"前概念"根深蒂固,自制力弱,课堂注意力集中时间较短,在规定时间完成学习任务难度较大.所以,教学设计采用"五让"教学法,充分发挥学生的主体地位和教师  相似文献

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"运动的钟变慢"是相互的.通过这个结论,本文进一步论证处在两个不同惯性系的两个时钟,它们的读数与观察者所处的惯性系无关.  相似文献

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1狭义相对论的困难洛伦兹变换表明,时间和空间存在内在联系."能量动量张量"的表达式和"质能关系式"等表明,质量和运动不可分割.光速不变原理和相对性原理告诉我们,一切惯性系都是平权的,不可能测出相对  相似文献

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A simple improved structure is designed to trap and launch two cold atomic balls vertically at the same time,which works like"two fountains",but is more compact since most components of the"two fountains" are shared.It is expected to improve the stability of the fountain markedly.  相似文献

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The cyclic evolution of a spin-1 system is studied under the spin-spin interaction between the transverse and the longitudinal states. The eigenstates of the systems are obtained by generalized and extended Jordan-Wigner transformation with an angle described the path of particle propagation. According to the wave functions of time evaluation for many-particle systems, the entanglement effects and geometric phase are observed. The systems with more than two particles, in contrast to the two particle system, evolve in time with two parameters.  相似文献

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For the two colour (35um and 812um) sensor fusion, an optical method can replace the electric time delay and integration (TDI) circuit. During the fusion process, there exits an optimal relative gain setting between the two preamplifiers of the sensors. The optical method can provide a real time (30 frames) single enhanced dual band thermal image with an improved signal to noise ratio and better system performance.  相似文献

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The analysis, with the use of two state vectors, of a quantum system, during the time interval between two measurements, leads to some amazing results, which seem to contradict our usual quantum common sense. We explore the questions of compatibility with the conventional quantum theory, uniqueness of pre- and post-selected ensembles, commutativity, simultaneity and reality of strong and weak values in the intermediate time, and the meaning of the weak value. Common criticisms are shown to be unfounded.  相似文献

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The effect of perceived spatial differences on masking release was examined using a 4AFC speech detection paradigm. Targets were 20 words produced by a female talker. Maskers were recordings of continuous streams of nonsense sentences spoken by two female talkers and mixed into each of two channels (two talker, and the same masker time reversed). Two masker spatial conditions were employed: "RF" with a 4 ms time lead to the loudspeaker 60 degrees horizontally to the right, and "FR" with the time lead to the front (0 degrees ) loudspeaker. The reference nonspatial "F" masker was presented from the front loudspeaker only. Target presentation was always from the front loudspeaker. In Experiment 1, target detection threshold for both natural and time-reversed spatial maskers was 17-20 dB lower than that for the nonspatial masker, suggesting that significant release from informational masking occurs with spatial speech maskers regardless of masker understandability. In Experiment 2, the effectiveness of the FR and RF maskers was evaluated as the right loudspeaker output was attenuated until the two-source maskers were indistinguishable from the F masker, as measured independently in a discrimination task. Results indicated that spatial release from masking can be observed with barely noticeable target-masker spatial differences.  相似文献

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Based on Valley’s quasi-cw approximation, the grating formation in materials exhibiting bulk photovoltaic effect on illumination with short light pulses (such as ns pulses) is investigated. We give the expression of the space-charge field, and find that it has two time constants. When considering and not considering the photovoltaic effect, the diagrams of two time constants as a function of irradiance in units of are the same. The energy required to erase a grating to 1/e of its initial value is also studied in the two cases. The two results are also the same.  相似文献

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The longitudinalz-pinch time evolution study between two conical electrodes was carried out by means of the interferometric and the schlieren methods, the discharge basic parameters time development (namely geometry, filamentary structure and electron density) was investigated.  相似文献

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Experiments were conducted to determine the extent to which listeners can discriminate between different combinations of interaural time and intensity for binaural stimulus configurations which eliminate loudness, lateralization, and image-diffuseness cues. A two-interval forced choice paradigm was used, and the task of the subject was to determine the order of two stimuli, each of which was a slowly gated 500-Hz tone with a combination of interaural time and intensity differences that resulted in a centered primary spatial image. The two stimuli to be discriminated were symmetric in that they differed only in the polarity of their interaural differences. Also, in order to reduce artifacts introduced by variations in the coupling of the earphones to the head, acoustic monitoring and compensation was performed both before and after each experimental run. The performance of the two most highly trained subjects is consistent with previous experimental results that indicate an incomplete trading of interaural time and intensity information. The subjective perceptions of these observers are not consistent with previous studies that describe a "time image" and a "time-intensity traded" spatial image.  相似文献

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The steady states of a simple nonlinear chemical system kept far from equilibrium are analyzed. A standard macroscopic analysis shows that the nonlinearity introduces an instability causing a transition analogous to a thermodynamic first-order phase transition. Near this transition the system exhibits hysteresis between two alternative steady states. Fluctuations are introduced into this model using a stochastic master equation. The solution of this master equation is unique, preventing two alternative exactly stable states. However, a quasi-hysteresis occurs involving transitions between alternative metastable steady states on a time scale that is longer than that of the fluctuations around the mean steady state values by a factor of the forme , where ø is the height of a generalized thermodynamic potential barrier between the two states. In the thermodynamic limit this time scale tends to infinity and we have essentially two alternative stable steady states.  相似文献