College Physics

“Gauge”in physics and its historic originits historic origin

SHI Yu

College Physics. 2017, 36(9): 1-5. doi:10. 16854 /j. cnki. 1000-0712. 2017. 09. 001

Abstract ( 1747 )

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We make a popular introduction to the gauge theories in physics，and then we discuss the origin of the word“gauge”used in physics. Originally，gauge means ruler or calibration standard. The use of“gauge”in classical electromagnetism started after Hermann Weyl had presented the gauge theory of a quantum charged particle coupled with an electromagnetic field in 1928 ～ 1929. If Weyl had not made a failed attempt in 1918 ～ 1919，trying to deduce electromagnetic vector potential through the scale change induced by parallel transport in spacetime， there would not have been the use of the word“gauge”for electromagnetic vector potential. We also review the contributions of Schrdinger，Fock and London.

Iterative calculation of the interactive force between two common axis uniform charged rings

KUANG Xiang-jun

College Physics. 2017, 36(9): 6-7. doi:10. 16854 /j. cnki. 1000-0712. 2017. 09. 002

Abstract ( 1136 )

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Abstract:Based on the Gauss theorem and Ampere loop theorem and combined with the axial symmetry axis of electric field，we derive the electric field of uniform charged ring by using the initial field intensity value on the axis. Then，the interactive force between two common axis uniform charged rings is calculated iteratively.

TEM wave in a coaxial transmission line with regular - hexagon - outer - conductor and circular - inner - conductor and its characteristic impedance

JIA Lan-fang，WANG Fu-qian

College Physics. 2017, 36(9): 8-12. doi:10. 16854 /j. cnki. 1000-0712. 2017. 09. 003

Abstract ( 1444 )

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The distribution of the TEM wave in a coaxial transmission line with circular - inner - conductor and regular - hexagon - outer - conductor is obtained by using numerical conformal mapping. The map of structure of electromagnetic field is plotted by using the software MATLAB and HFSS，and its characteristic impedance is calculated. Furthermore，its characteristic impedance is calculated. This research result has certain reference value to calculation of the decay constant of the transmission line，realization of its power capability，consideration of its power coupling and design of the related active device.

Identical particles: unnoticed off - diagonal matrix elements of two - body operators

ZHU Zheng

College Physics. 2017, 36(9): 13-14. doi:10. 16854 /j. cnki. 1000-0712. 2017. 09. 004

Abstract ( 1252 )

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Under occupation number representation，an unnoticed kind of off - diagonal matrix elements is derived for both bosons and fermions

The capacitance for bipolar column equivalent coordinate capacitor

LIN Xiao-ting，CHEN Gang，WANG Qiu-yu

College Physics. 2017, 36(9): 15-19. doi:10. 16854 /j. cnki. 1000-0712. 2017. 09. 005

Abstract ( 1204 )

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The bipolar coordinate system is a common coordinate of orthogonal curvilinear，which is suitable for showing the relationship between the conductor post plates. Under the condition of bipolar column coordinates，we discuss the confocal and coaxiality arc column conductor capacitance being represented by the two orthogonal curvilinear coordinates.

Two kinds of balance circuits—From classic to modern

SHEN Shi-zhang

College Physics. 2017, 36(9): 20-23. doi:10. 16854 /j. cnki. 1000-0712. 2017. 09. 006

Abstract ( 1379 )

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Two kinds of balance circuits are studied. They can explain various null circuits from a uniform view， such as potentiometer，Wheatstone bridge and operational amplifier. The usage on operational amplifier can overcome the limitation of classic amplification of balance circuit. Especially，it makes the balance circuit reaching equilibrium automotccally and immediately，and can treat the signal form DC to AC，including LF and HF.

The relationship of the spatial orientation between the crystal columns and the crystal surface of the same exponential in cubic crystal

QIN Zao-hui，HU Jian-min，WANG Yue-yuan，NIU Li

College Physics. 2017, 36(9): 24-26. doi:10. 16854 /j. cnki. 1000-0712. 2017. 09. 007

Abstract ( 1757 )

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By using the relation between the positive lattice and the negative lattice，the spatial orientation of the crystal columns and the crystal plane of the same exponential are inferred in the cubic crystal in the cell - based vector and unit cell axis vector coordinate system. The results show that the crystal columns are perpendicular to the crystal plane of the same index in cubic crystal in the axis vector coordinate system. The spatial orientation of the same index crystal lattice is related to the specific crystal lattice structure in the cell - based vector coordinate system.

The relativistic rotation of the rigid pole

CAO Ze-xin1，LIU Ling2

College Physics. 2017, 36(9): 27-30. doi:10. 16854 /j. cnki. 1000-0712. 2017. 09. 008

Abstract ( 2093 )

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It is pointed out in the paper that the Galileo formula is not self - consistent in the framework of the special theory of relativity via the investigation of reviewing and reconsidering the pole's uniform rotation within the special relativity. A new formula for the rotate velocity of the pole，which is rotating uniformly，is derived in the special relativistic limits by using the special relativistic delivery formula in the inertial system，and by continued fraction and recurrence relation. In the new relative rotation formula，the rotational linear velocity is always less than the velocity of light. Therefore，the problem of horizon in the Galileo rotation formula can be solved. The self - consistence of the new relative rotation formula is verified，and the comparison of the transverse Doppler shift between the relativistic rotating pole and classical rotating one is made. The result can be used to test the relative rotational formula.

Studies of the axial magnetic field distribution for a rectangular solenoid with finite dimension

PEI Shi-lun1，ZHAO Shi-qi1，2，LI Xiao-ping1

College Physics. 2017, 36(9): 31-34. doi:10. 16854 /j. cnki. 1000-0712. 2017. 09. 009

Abstract ( 1389 )

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For the mutiturn and multilayer solenoid with finite rectangular dimension，it is very difficult to obtain the analytical formula for the axial magnetic field distribution. Based on the analytical formulae for the single turn rectangular wire and that for the multitun and single layer rectangular solenoid，the sum expression of the axial magnetic field distribution for the the mutiturn and multilayer solenoid is obtained. A Matlab script is written based on the slice and sum method proposed in this paper. Finally，an analysis on the axial magnetic field distribution for a beam orbit corrector most applied at the low energy stage of the accelerators is done. The result calculated by the Matlab script and the numerical simulation result by CST EM studio agree well

Measurement of magnetostrictive coefficient using micro - displacement sensor

NI Min1，ZHANG Yi-fan1，ZHEN Yuan-min2，DONG Lin1，ZHAO Cai-an1

College Physics. 2017, 36(9): 35-37. doi:10. 16854 /j. cnki. 1000-0712. 2017. 09. 010

Abstract ( 1257 )

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Magnetostrictive measurement principle and the parameters are outlined，which is designed to replace　commonly used semiconductor strain gauges of aluminum wire resistance strain gauges，the development of a new type of semiconductor micro - displacement sensor，and measuring the standard length of the micro - displacement sensor calibration. It can be used to measure directly a small length of the material in a magnetic field variation. 　Which addresses the teaching experiment that could not easily replace the original samples of the trouble，but also improves the measurement sensitivity and accuracy，a variety of materials accurately measured the magnetostriction coefficient curve.

Position - sensitive plastic scintillator spectrometer

LOU Jian-ling1，WANG Xiao-tian2，XU Jin-yan1

College Physics. 2017, 36(9): 38-43. doi:10. 16854 /j. cnki. 1000-0712. 2017. 09. 011

Abstract ( 827 )

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In order to close to the scientific frontier，based on a long plastic scintillator，a new experiment measuring time in magnitude of ns order is established. The experiment is named position - sensitive plastic scintillator spectrometer. The time difference of signals read by both ends of long plastic scintillator can be used to determine the radiation position because the transition path length and time of fluorescent signal in the long plastic scintillator is different when the radiation position is different. The students are required to observe the characteristics of each output signal，and to adjust electronics parameters and temporal relations of two time signals using an oscilloscope，which can help them learn and master how to use oscilloscope in the experiment. It is found that this research experiment is suitable for the senior under - grade students via the teaching practice of three years from 2013 to 2015.

Study of the application of virtual instrument in nuclear technology experiment teaching

TIAN Li-chao，JIANG Jing，MA Yan-yun

College Physics. 2017, 36(9): 44-48. doi:10. 16854 /j. cnki. 1000-0712. 2017. 09. 012

Abstract ( 959 )

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Nuclear technology and nuclear safety is a highly practical subject and experimental teaching is the key link of the training of students major in nuclear technology. The current situation of the traditional nuclear technology experiment teaching is introduced，and the features and advantages of the application of virtual instrument in nuclear technology experiment teaching are also presented in this paper. An experiment system used in the position sensitive detector teaching is developed based on LabVIEW in our lab，indicating the feasibility of the application of virtual instrument in nuclear experiment teaching.

Study and analysis on seven early female physicists studying abroad

YIN Xiao-dong1， ZHOU Jin-rui2

College Physics. 2017, 36(9): 49-56. doi:10. 16854 /j. cnki. 1000-0712. 2017. 09. 013

Abstract ( 1446 )

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The paper accounts the seven women physicists who received PhD abroad in the early of the twentieth century before new China. They studied respectively in USA，Germany and UK，and made outstanding achievements in spectroscopy，metal physics，statistical physics and nuclear physics during abroad and after their return. Their researches abroad are introduced and analyzed systemically，which can provide some enlightenments to us.

Security protocol in wireless sensor networks based on neighbor node cooperation

FAN Qiu-sheng

College Physics. 2017, 36(9): 57-61. doi:10. 16854 /j. cnki. 1000-0712. 2017. 09. 014

Abstract ( 823 )

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Nowadays，with the development of network communication technology，the wireless sensor networks has been widely used in various industries and social fields，which is becoming more and more perfect and mature. With the continuous breakthrough of its technology，now it becomes one of the three pillar industries of information technology in China with the communication technology and computer technology，and plays a very important role in the industry progress and economic development. However，the wireless sensor technology is composed of a large number of stationary or moving sensors in the basis of a self - organizing way or multi hop wireless network，so it is easily affected by external environment and can not work normally. Therefore，how to design a high efficiency and saving energy and high safety factor of wireless sensor network security protocol has become an important topic in the field of information technology，and it is also a problem. This paper describes the wireless sensor network adjacent node cooperation advantages and security analysis based on this key management scheme from the perspective of the wireless sensor network protocol working mode and network key management perspective，hoping to achieve a security protocol for wireless sensor network break.

Research on application of ant colony algorithm in intelligent LED street lamp control

PAN Wen

College Physics. 2017, 36(9): 62-68. doi:10. 16854 /j. cnki. 1000-0712. 2017. 08. 015

Abstract ( 924 )

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LED streetlamp monitoring system is an application of PLC( power line communication) technology. 　A LED street network addressing algorithmis developed，which can be used in low voltage distribution network based on ACA( ant colony algorithm). Wepay focus on the objective function，the pheromone updating rule and state transition rule and search and other elements of the revision and improvement，it constructs not only the automatic routing model，but also a framework of automatic routing protocol. With this model，the low - voltage distribution network channel quality can be identified dynamically. Through the change of channel quality，routing power linecommunication network can complete the dynamic maintenance，so as to further realize the reliability of communication network. Finally，the practice and reliability of this method are verified by the simulation model of the channel and the assistance of the field test.

Introduction of quantum discord and its calculation in a certain system

LI Kai1，LIU Yi1，ZHU Qin-sheng2，WU Hao2，WU Ming-he2，TENG Bao-hua2

College Physics. 2017, 36(9): 69-72. doi:10. 16854 /j. cnki. 1000-0712. 2017. 09. 016

Abstract ( 1412 )

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Quantum discord is an important concept of quantum information，which is used to evaluate quantum correlation among systems and performs more accurately than quantum entanglement. In this paper，the concept of quantum discord，its recent developments and applications are introduced. By considering the transverse field Ising system as an example，a method to calculate quantum discord is elaborated. Thereby the system's quantum discord is obtained and a three - dimensional image characterizing the features of quantum discord is plotted.

Electromagnetic momentum and stress tensor in media

CUI Yuan-shun，JIANG Cheng，LI Jian-hua

College Physics. 2017, 36(9): 73-81. doi:10. 16854 /j. cnki. 1000-0712. 2017. 09. 017

Abstract ( 1746 )

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Aiming at the problems of the electromagnetic momentum and stress tensor in medium，and committed to the combination with the theoretical research progress in recent years，the distinction and relation for the different forms of the electromagnetic momentum and the stress tensor in medium are compared and analyzed. Their physical meaning and functions are explored according to the Maxwell equations，Lorentz force and the momentum conservation law. We try to provide the references for the related teaching and research work.

College Physics. 2017, 36(9): 82.

Abstract ( 768 )

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