In recent years, with the development of related theories of wire gratings and surface plasmons, it has become a trend to study gratings based on surface plasmonic wire gratings. Most of today's devices are pursuing miniaturization and high integration. Surface plasmons have made great contributions to the research and development of grating-based devices by virtue of their unique properties. Based on the finite element method we studied the surface plasmonic wire gratings. The finite element simulation model and analysis of plane electromagnetic wave incident by line grating on dielectric substrate are carried out by COMSOL software. The refraction, transmission and reflection coefficients of TE wave and TM wave of transverse electromagnetic wave, specular reflection and first-order diffraction are calculated. The results show that the sum of all coefficients is always less than 1. The value of mirror reflection coefficient increases relatively steadily with the incident angle of TE wave, which is more obvious when TM wave is incident. About half of the wave is absorbed by line. Another important feature of TM wave is that mirror reflection hardly occurs near 50-60 degrees.

When the laser is shot into two parallel plane mirrors, it will cause multiple reflections. The laser optical lever method based on this principle has the advantages of simple optical path and fast reading and so on. However, there is a discrepancy between the theoretical analysis and experimental process in the incoming (inverse) shooting point of the laser in the plane mirror. The difference increases with the increase of reflection times. Moreover, the initial incidence angle of the laser cannot be ignored in the case of  fewer reflection times, so the original theoretical formula needs to be modified to avoid the error of measuring small distance. We modify the original theoretical formula of the multi-reflection optical lever method in measuring linear expansion coefficient of metal. By analyzing the experimental data, the more accurate linear expansion coefficient of metal is obtained.

The response time of liquid crystal is a significant parameter to describe the performance of liquid crystal display. It is important to study the influence of driving voltage on the response time of liquid crystal to determine the optimal operating voltage of LCD. In this study, the calculating equation of the rising and decline time of the director under strong and weak anchoring conditions is determined by theoretical analysis. The range of driving voltage is determined according to the electro-optic effect curve, and the response time variation feature in the range of driving voltage is analyzed. The results show that for the liquid crystal used in this study, the response time increases first and then decreases with the increase of driving voltage, the inflection point is about 3V; with the increase of driving voltage, the falling time has the characteristics of inverse ratio of driving voltage, while the rising time has obvious sectional characteristics. In the range of 2-2.5V, the rising time is almost unchanged, and then increases in the range of 2.5-5V. Combined with the dynamic response process of liquid crystal molecules under the driving voltage, the reason why the rising time presents piecewise characteristics can be explained by simulating the calculation equation of the rising time and falling time of the directional vector under strong and weak anchoring conditions.

Transition metal borides (TMBs) have long been considered as potential superhard materials due to it have strong B-B covalent bond and TM-B bond. Many TMB_s which have been predicted as superhard material have layered structure with TM layers and B layers stacked alternately. Up to now, several TMB_s have been synthesized and declared as superhard materials. However, none of them demonstrated an asymptotic hardness larger than 40 GPa which is generally accepted as the threshold of superhard materials. However, there is a paucity of reports about why can not form superhard materials in TMB_s. In this paper,  rhenium diboride、tungsten diboride and molybdenum diboride are considered as the material for exploring the hardness mechanism. But the TMB_s, which has been synthesized, do not exhibit superhard properties. In order to explain the reason why the synthesized TMBs do not exhibit superhard properties and to explore the hardness mechanism of TMBs, In this paper, molybdenum diboride is considered as the material for exploring the hardness mechanism. We found that the chemical bonds between metal layer and boron layer play an important role in determining the hardness. In three materials, ionic character bonding is the major chemical bonding between TM atoms and B atoms which is thereason that this three materials can not be superhard material. Our results are helpful to understand the hardness mechanism and design superhard materials in TMBs.

In this paper, a simple Mach-Zehnder interferometric optical path is designed to obtain suitable interference fringes. By demonstrating the interference conditions such as the experimenter contacting the experimental platform, talking near the optical path, walking near the platform and floor vibration, the influence of the above vibration interference on fringe drift is characterized by using light intensity sensor to monitor the fringe changes in real time. The above results will be helpful for students to understand the interference factors of fringe drift in holographic photography directly, and help students avoid the above problems and improve the success rate of holographic photography experiment.

In this paper, the quantitative function of the short-time temperature rise rate of LED is deduced theoretically without considering the heat dissipation from the LED devices to the surrounding environment. A new idea and method for measuring the temperature rise rate of LED in a short time is proposed experimentally. Moreover, the relationship between the temperature rise rate and the change of power-on time, current and junction temperature is studied, and the importance of device heat dissipation is qualitatively discussed. The results show that when the terminal voltage and current of the LED are constant, the temperature rise rate of the LED is independent of time in a short time; when the junction temperature of the LED is constant, the temperature rise rate changes linearly with the current; when the current passing through the LED is constant, the temperature rise rate increases first and then decreases with the increase of junction temperature, and reaches the extreme value when the junction temperature is 60℃. Therefore, it is recommended that the temperature should be lower than 60℃ so as to ensure the good heat dissipation of LED device.

Using Bingham fluid model, the braking torque of the magnetorheological fluid disc brake was studied, and a single disc brake structure with outer winding coil was designed. COMSOL software was used to model the structure, simulate the electromagnetic field, calculate the braking torque and optimize the structural parameters. The research shows that the brake torque has nothing to do with the angular velocity of the shear disc, and the brake can obtain a relatively stable brake torque during the braking process. Under certain magnetomotive force, when the radius of shear disc increases, the braking torque of disc brake will increase gradually. Increasing the thickness of the magnetic-conducting shell is beneficial to restrain the magnetic field line and improve the braking torque.

Organic-inorganic hybrid lead halide perovskites have recently been considered as competitive optical optoelectronic materials due to its advantages of solution processability, strong absorption, and high carrier mobility. In this work, we introduce a method for improving the morphology of perovskite films. Isopropanol (IPA) was introduced as additive to MAPbI3 precursor solution and one-step method was used to fabricate perovskite films with large grain size. Perovskite solar cells were prepared and the concentration of IPA was optimized. Power conversion efficiency of 14.6% was achieved by solar cells based on 6% v/v IPA solution, which enhance 40% compared with reference devices.

Michelson interferometers are precision instruments that measure tiny lengths.The counting of the isohedral interference fringe produced by Michelson interferometer is an important step in measurement.In order to realize SCM automatic counting ,the acquisition and interference fringe is the precondition. In this paper,the isodip interference fringe  ang its collection and resolutin  are introduced in detail.

When the metal wire is subjected to axial tension, its length and cross-sectional area will change slightly, and its resistance will also change accordingly. A new method for measuring the elastic modulus of the metal wire with high precision and easy operation was designed according to the change in resistance of the metal wire during stretching with the Wheatstone bridge.

Based on the Huygens–Fresnel principle, the intensity distribution expression of double-slit interference with the consideration of slits width is derived. According to the expression, the theoretical results are simulated. It is found that, if the width of the slits cannot be neglected, the interference fringes is not the ideal fringes with same intensity and spacing, but the intensity magnitude decreases with the radial distance increases from center. Moreover, if the distance between two slits is integral multiple of the width of each slit, the fringe may disappear. The explanation of the theoretical results is presented. In addition, the experiment is carried out, and experimental observation is consistent with the theoretical simulation. It is a meaningful discussion for further understanding the teaching and experiment of double-slit interference experiment.

Based on the concept of splitting wavenumber difference, this paper clarifies some confusing and incomprehensible problems in electron charge-mass ratio measurement experiment by Zeeman effect, such as the determination of the observed object and its wavenumber difference, the spectrograde overlaping method, etc. According to free spectral range of F-P etalon and the wavenumber difference distribution map of Hg 546.1nm Zeeman splitting spectral, the spectrograde overlapping pattern are deduced. It can improve students'understanding of measurement methods and also provide a certain reference for teaching.

Chaos Theory is so complicated and abstract that most of the studies for it are simulate. Thereby, in this passage, a compound pendulum system driven by periodic external forces is built. The data are collected by the contactless Angle sensor and transmitted to the computer in real time after being transformed by AD. LabVIEW software is also used for data processing and analysis so as to show chaos phenomenon in a simple and intuitionistic way. By adjusting the parameters of the system, the angular timing sequence diagram, angular velocity timing sequence diagram and phase diagram of the complex pendulum system moving without driving force and with driving force are described. The sensitivity of initial value and the entire process of the changing of the system from period to chaos are discussed in detail, which realizes the quantitative analysis of chaotic phenomena.

A vehicle flow detection system is designed on the base of the pymelectric infrared devices. It consists of a weak signal processing and amplification circuit of pymelectric infrared sensor, real-time clock circuit, STC89C52 microcomputer and its peripheral circuit. The system is placed at an appropriate location of the road side, and when a car passes by the detection area, the system composed by two sets of pymelectric detectors with a certain spacing can well receive successively the infrared radiation emitted by the vehicle because of the good focusing ability of Fresnel lens. The time interval between two sets of infrared signals is calculated by the clock circuit to judge whether the vehicle is passing by. The result will be shown on the 12864 LCD screen. Through the outside tests, the system can realize the on-line inspection of traffic flow, and has a higher ratio of quality to price.

The coefficient of liquid expansion is the ratio of the volume change to its volume at 0 ° C for every 1 degree Celsius change in temperature. In this paper, the experimental device for measuring the liquid expansion coefficient is assembled. The capillary and the temperature sensitive bubble are assembled into a container for the temperature sensitive liquid for experiment. Then, the constant temperature water bath is used as the device for changing the temperature of the liquid, the experimental data is recorded, the data is processed, and the water is obtained. And the coefficient of expansion of ethanol. The experimental conclusion has an important reference for the design and calibration of the thermometer. The error between the experimental results and the standard values is 2.9% and 3.0%, respectively, and the relative error is small, indicating that the experimental scheme is feasible.

In recent years, pyroelectric testing technology has been widely used to test unconventional ferroelectric bodies at low temperatures, especially the ferroelectric polarization of the second type of multi-iron materials, but most of them are used by researchers for professional research.

At present, the quality-oriented education of college students is in full gear. This technology can enable students who participate in the scientific research training program to do some simple subject research, train and develop some basic scientific research thinking, habits and skills.

This paper introduces the basic principle, experimental instrument and experimental method of pyroelectric technique for measuring ferroelectric polarization, and illustrates some experimental techniques and precautions.

The experimental principle of the radius of curvature of lens by Newton’s ring and the effect of the size of dark spot in the center of Newton’s ring on the radius of curvature are discussed and analyzed. The center of different types of Newton’s ring are adjusted, the experimental data are measured and processed repeatedly. The results indicate that the lager the dark spot in the center of Newton ring, the lager the radius of curvature, furthermore, the lager the experimental error corresponding to it.

The influence of angular amplitude in the experiment of measuring acceleration of gravity by simple pendulum is studied. The results show that arbitrary choice of angular amplitude may increase the uncertainty of experimental results and result in artificial systematic deviation. In experiments, the same angular amplitude should be chosen under different pendulum lengths.

Boron carbide (B₄C) is the third hardest materials in the nature following the diamond and cubic boron nitride. However, due to bulk B₄C is hard to be synthesized and the fracture toughness of B₄C is very low, B₄C can not be widely used as superhard material. In this work, High-quality bulk B₄C was successfully prepared at high pressure and high temperature. It is worth nothing that the as-synthesized B₄C possess high hardness and high fracture toughness （4.51 MPa?m^1/2）which are superior to single crystal. The high Vickers hardness and high fracture toughness of B₄C are attributeed to its high densification and nanosheet structure.

In this paper, an overcurrent protection circuit using a thyristor as the main control component was designed. The working principle was introduced, and the current limiting value as well as the protection delay time were tested and analyzed. The circuit is simple and effective, meantime with high sensitivity, reliability and stability. It can be applied in various electrical experimental devices for over current and short circuit protection.

Adaptive filter is a kind of filter which can modify its parameters in real time according to the noise characteristics, so as to achieve the best filtering effect. Designed a complete adaptive filter device. At first, use the adder and the phase shifter circuit to deal with the noise mixed with original signal. Then import the mixed signal in a FPGA module after AD transform, and complement a least mean square error (LMS) algorithm for adaptive filter on FPGA platform. Finally, export the output signal after DA conversion and it can be observed on the oscilloscope. The experimental results show that the adaptive filtering scheme can effectively filter sinusoidal wave, triangular wave and gaussian noise which are more than 10Hz differ from the original signal in the frequency range of 1-200KHz.

An electromagnetic positioning frame for measuring liquid viscosity coefficient is designed to solve the problems existing in the existing instrument for measuring liquid viscosity coefficient by falling ball method. In this paper, the experimental equipment was improved, through the principle of electromagnet suck balls, effectively reduce the pollution caused by experimental operation experimental liquid experimental liquid pollution and the outside world, and the design of the cone type electromagnet and semicircular canals the whereabouts of precise control of the ball position, the largest possible meet the requirements of the experiment principle of ball falling position, effectively eliminate the traditional instruments existing many problems when doing the experiment, ensure the accurate and metal ball along the center of container, the experiment operating accuracy has improved significantly.

Based on the virtual instrument technology, based on the HLC-RLC-III model RLC comprehensive experimental instrument, the data acquisition card is used to convert the analog signal output by the experiment instrument into a digital signal that can be processed by the computer, and the virtual instrument program compiled by LabView is used to realize the measurement. Design and construction of an experimental system for the characteristics of RLC series resonant circuits. Compared with the traditional experimental scheme, the functions of data acquisition, signal processing and data display are realized by virtual instrument programs. These functions can be redesigned according to the experimental content. Therefore, the system has flexible expansion in experimental content. The system can not only complete the basic experimental teaching of measuring the basic characteristics of the RLC series circuit, but also carry out design experimental training for students, thereby mobilizing the enthusiasm and creativity of students and improving students' practical ability.

As the core course of applied physics major, Applied Optics has strong practicability. Aberration is an important parameter to characterize the imaging quality of optical system, and it is the most important concept in Applied Optics. Axial spherical aberration is one of the most basic and important geometric aberrations. In this paper, Zemax is used to simulate the measurement of spherical aberration in the optical system. Through the method of ray tracing, the experimenters can deeply understand the causes of spherical aberration and get familiar with the experimental principle, which has a positive guiding effect on the measurement of spherical aberration.

Half-wave rectifier is widely used in teaching as one of the applications of diodes, but it has not paid enough attention to the experimental phenomena of the cut-off state characteristics of diodes. Compared with the resistance-capacitance filter of half-wave rectifier, inductance filter is seldom mentioned to arouse interesting of students for knowledge. Therefore, based on the experimental results of Multisim 10 simulation software, it is verified that the cut-off state of the diode has the characteristics of fixed capacitance, and the influence of the ratio of filter inductance to load on the filtering effect is analyzed.

This paper introduces the specific application of Mathstudio in the ISEC science and engineering course of Inner Mongolia University for Nationalities from two aspects, namely, Mathstudio's application in linear algebra and experimentsl data processing of conceptual physics. The results show that interactive & participatory teaching methods, content designs which are close to life and have theories combined with reality, will activate students not only to improve their abilities but also to increase their interest in learning. It’s a positive attempt during the teaching reform process of our university.

This paper analyzes the reasons for the problems in the connection of physical experiments between college and middle school under the background of the new college entrance examination. Combined with the investigations, this work puts forward the reform measures in the aspects of communication, curriculum arrangement, teaching contents and teaching methods between them, realizing the effective connection between college physical experiments and middle school physical experiments.

With China's higher education reform entering the deep water area, private colleges and universities are facing more and more severe problems in personnel training. Colleges and universities have taken measures to deepen the curriculum reform. Taking the college physics experiment course of Changchun University of Architecture and Civil Engineering as an example, this paper expounds the systematic reform measures in the aspects of teaching concept, curriculum system, curriculum content, equipment, teaching mode, means and methods, etc. to give full play to the role of college physics experiment course in cultivating students' comprehensive application ability, engineering practice ability and innovation ability.

As essential parts of engineering education，the practice education is an important way to cultivate student abilities in terms of thinking and solving problems, professional knowledge and skills, engineering awareness and scientific innovation, etc．With the guidance of new times national higher education policy, take the photoelectric information science and engineering major of Anhui university as an example, the setting of practice education curriculum system, platform construction ways, and course content design, including purpose，ideas，contents and effects, is introduced in this paper. The useful exploration is developed to provide reference for the cultivation of innovative engineering talents for special industries with general specialty.

This paper focuses on the in-depth development of the existing physical experimental instruments in the laboratory, and explores and develops the relevant experimental content, experimental materials, and experimental demonstration dissemination methods. This method expands the physical experimental content. It has consolidated the understanding of physical experimental principles, realized the maximum utilization and greater use value of experimental instruments, improved the utilization rate of experimental instruments, and played a good demonstration role in energy conservation.

This paper mainly summarizes and discusses the construction process of the virtual simulation experiment project of "Nuclear Physics Experiment".In view of the lack of curriculum content caused by the inability to preserve radioactive sources in the experimental teaching activities of nuclear physics in universities, the Physics Experimental Teaching Center of Northeastern University has developed a comprehensive experiment of nuclear physics. This experiment project has created a new model of VR open virtual simulation experiment teaching , optimized and developed the comprehensive experiment teaching of nuclear physics. Students 'subjectivity in experimental teaching activities, cultivating students' innovative ability and scientific literacy, this teaching mode is being used in experimental teaching, and has been awarded the national virtual simulation experimental teaching project.

The physics plays an extremely important role in the natural science, and the history of physics also plays an important role in the teaching process of university physics. In this paper, the education function of the history of physics is introduced and analyzed in cultivating students' scientific quality, innovative quality and humanistic quality. According to the education function of the history of physics, the principles and methods of reference for the history of physics are analyzed in university physics teaching. At the same time, combining with the current teaching process of university physics, this paper makes a questionnaire survey and analysis of students' attitudes towards the history of physics, which has certain reference value and significance for university physics teaching.

The course of college physics experiment, which is one of the key factors influencing teaching quality of the undergraduate student, has not been paid any attention in many colleges. This influences seriously the teaching quality of the course of college physics experiment. It is necessary to expound and summarize the functions and significance of the course of college physics experiment. In this paper, the functions and significance of the course of college physics experiment have been expounded and summarized from six aspects. It is hoped that can help to improving the teaching quality of the course of college physics experiment.