bluuebunny/crossref_metadata_2025 huggingface dataset:
Teachers Grow Mathematically Together: A Case Study from Data Analysis
Authors: McClain Kay , Schmitt Paula
Published: December 2020

During the past two years, we have been engaged in a collaborative effort focused on improving middle-grades statistics instruction in the Madison School District in Phoenix, Arizona. Part of our work has entailed rethinking what might constitute an instructional “unit” that highlights the importance of students' engaging in genuine data analysis while paying attention to the conventions of the discipline (e.g., calculating measures of central tendency and using correct procedures for creating graphs). Central to our exploration (or lack thereof) of the tasks. In so doing, it would provide intellectual resources for the teachers to use as they anticipated how students might reason. The cyclic process of task solving and task posing supported the teachers' developing understandings of the mathematics they teach while placing students' ways of reasoning in the foreground. This process presented a continuous improvement model that guided the work of the group. An overarching goal was to investigate what mathematics should comprise the middle-grades units on statistical data analysis. This information could only be examined by first understanding the mathematics.
The Beauty of Geometry
Authors: Morris Barbara H.
Published: December 2020

Stained-glass-window design is an aesthetically pleasing and realistic application of geometry. Examples of these designs date back to medieval times. Frank Lloyd Wright's stained-glass creations are modern examples of combinations of light, color, and form that fascinate and delight the viewer (Carli 2001). This fascination and delight can be brought to life for students with a stained-glass-window geometry project.
The Car Wash
Authors: Kersaint Gladis
Published: December 2020

The editorial panel is presenting the following problem to stimulate submissions to “The Thinking of Students” department. We encourage teachers to try this problem with students and analyze the different strategies that they use to solve the problem.
Transformations and Technology: What Path to Follow?
Authors: Glass Brad
Published: December 2020

Many of the new elementary sCHOOL and middle school mathematics curricula provide students with opportunities to encounter geometric transformations. Some of the curricula (e.g., MATHThematics, Math Trailblazers, and Investigations in Number, Data, and Space) introduce transformations (such as translations, reflections, and rotations) as motions (slides, flips, and turns) undergone by familiar shapes. How can we make the most of these experiences to ensure that our students are prepared for high school geometry courses? One way is to find out what students understand about transformations and to address any misconceptions they have regarding transformations. In working with eight eighth-grade prealgebra students, I identified one possible misconception as they completed a set of activities using The Geometer's Sketchpad (Jackiw 2001). The students focused on the path followed by a shape, rather than on the relationship between the preimage and image shapes, thereby leading them to incorrect conclusions regarding the equivalency of transformations. The technology-based activities helped some of the students begin to rectify this misconception.
Measurement: What's the Big Idea?
Authors: Martinie Sherri
Published: December 2020

The value of building a strong understanding of measurement must not be underestimated. The skills of measurement are frequently encountered in realworld situations, from measuring the size of a room to measuring the time it takes to run a mile in gym class to the amount of water used when a faucet drips. Instruction involving measurement should focus on teaching students, K–12, to 'understand measurable attributes of objects … and apply appropriate techniques, tools, and formulas to determine measurements' (NCTM's Principles and Standards for School Mathematics, p. 44). These measurements may be one, two, or three dimensional and involve length, weight, capacity, time, or temperature. However, research on measurement reports that this concept harbors the largest discrepancy between learning opportunities and actual performance, meaning that although students are instructed in measurement skills in school, they cannot show that they have learned the concept.
Learning about Area by Working with Building Plans
Authors: Joram Elana , Oleson Vicki
Published: December 2020

Area measurement is one of the most difficult topics in measurement that teachers cover in the K–6 curriculum. Several authors (Nitabach and Lehrer 1996; Outhred and Mitchelmore 2000) have noted that students' difficulties with area stem from an overreliance on the area formula, with little accompanying understanding of its conceptual basis. Students in the early elementary grades measure objects directly with instruments such as rulers, and in this sense, they see the units that they are “counting.” Calculating the area of a rectangle by means of the a = l × w formula, however, involves a shift in thinking, because area is derived from measurements that have been obtained with a ruler, rather than by directly counting units. When using the formula, students do not have to think about units covering space or an object. When designing a unit of instruction on area measurement, we began the process with this question: How could we help students see how direct measurement (counting units) is connected to indirect (a = l × w) measurement? Another way to frame the question is this: How can students better understand the conceptual basis of area measurement?
Balloons on the Rise: A Problem-Solving Introduction to Integers
Authors: (Andy) Reeves Charles A. , Webb Darcy
Published: December 2020

Have you ever had students ask you for “more of those kinds of problems?” We have, and the topic was integer arithmetic—a difficult topic for many middle grades students.
Dramatic invasion of the orbit by periocular cutaneous squamous cell carcinoma
Authors: Oulehri Aida , Elloudi Sara , Baybay Hanane
Published: December 2020

The periocular skin is susceptible to numerous benign and malignant neoplasms. Malignant skin tumors of the periocular area are very particular; they can present differently, are rapidly aggressive and pose a real therapeutic challenge. Aggressive forms occur mostly in immunocompromised individuals. A complete destruction of the orbit is rare and the initial seat is most often the eyelid. We report the case of an immunocompetent 70-year-old patient with destruction of the entire orbital region including the eyeball secondary to the extension of squamous cell carcinoma of the internal canthus.
The role of general practitioners in the prevention and screening of skin cancer: a cross-sectional study in Morocco
Authors: Oulehri Aida , BayBay Hanane , Filankembo Kava Angéla
Published: December 2020

Background: Given the high incidence of skin cancer (SC) in several countries around the world, general practitioners (GPs) are playing an increasingly important role in the prevention and early detection of this disease. The main objective of our study was to evaluate the current role of GP’s in the prevention and early detection of skin cancer. The secondary objectives were to determine the GP’s level of knowledge, their lack of information and their need for education on skin cancer. Methods: We realized a cross-sectional descriptive survey by means of a questionnaire among GPs practicing in the private and public sector in the city of Fes. Results: 158 general practitioners issued a completed and usable questionnaire. The average age was 45.91 years, sex ratio M/F =1.05. The number of years of exercise varied between one year and 39 years with the predominance of the bracket; between 10 and 20 years of experience. 47.5% estimated that their dermatological activity represented less than 10% of their overall activity. The majority of physicians surveyed stated that they rarely or never carry out all practices related to skin cancer prevention and screening, the main obstacle being the difficulty in recognizing suspicious lesions. 60.8% of physicians stated that they never gave photoprotection advice to their patients. 1.3% had participated in a specific training course on skin cancer screening; 92.9% selected “lack of proposal” as their reasons for non-participation in such a course. Among the general practitioners in the study, 91.1% considered that it was essential to reinforce their knowledge, particularly in terms of training in the recognition of suspicious lesions (88.6%). The evaluation of knowledge about skin cancer showed a good level of knowledge among 54.7% of the doctors questioned and an insufficient level among 43.1%. Conclusion: Most GPs are willing to take part in SC prevention and screening in their daily practice. However, our results demonstrate a high need for additional education and training.
Evolution of the mechanism of state regulation of Soviet foreign policy propaganda in print media (1917-1963)
Authors: Krasnoshchekov Nikita Alekseevich
Published: December 2020

This article examines evolution of the mechanism of state regulation of Soviet foreign policy propaganda in print media in the period from 1917 to 1963. The goal consists in studying the process of key structural and normative legal changes within the mechanism of state regulation of Soviet foreign policy propaganda in print media, as well as in highlighting the characteristic features of main stages in evolution of the mechanism of state regulation. The subject of this research is the analysis of party and government documents that regulate the activity of propaganda agencies and foreign policy agenda in print media, based on which an attempt is made to determine the primary trends in regulation of foreign policy propaganda in press. The object of this research is the structural changes in public administration with regards to foreign policy propaganda. Special attention is given to the administrative aspect and normative legal base, which are the framework for functionality of the apparatus of Soviet propaganda. The author determines the key stages in formation of foreign policy propaganda in print media, and concludes that the XX Congress of the Communist Party of the Soviet Union marks the establishment of holistic structure of foreign policy propaganda, as well as the emergence of new party and government branches of cultural-ideological impact on the Western countries. The scientific novelty lies in an attempt of comprehensive examination of the process of amending the basic normative legal documents that regulate the activity of public administration authorities in the area of foreign policy propaganda in print media over the period from 1917 to 1963. Based on these structural and normative legal changes, the author characterizes the stages of evolution of the mechanism of state regulation of this sphere.
Foreign policy of the First Czechoslovak Republic in the coverage of Soviet historiography
Authors: Martiushev Aleksandr , Terekhov Oleg Eduardovich , Terekhova Oksana Nikolaevna
Published: December 2020

The goal of this article consists in determination of the key aspects of foreign policy of the First Czechoslovak Republic, described in the Soviet historical science since the end of the World War II until dissolution of the Soviet Union. The subject of this research is the writings of Soviet historians dedicated to examination of foreign policy of interwar Czechoslovakia. The object of this research is the Soviet historiography of the late 1940s – late 1980s. The interest towards foreign policy problematic is substantiated by its crucial importance for the existence of the First Republic, which fully depended on the stability of the Versailles System of international relations that gave rise to it and was eliminated along with it. Analysis the works of Soviet historians allows concluding that the main vectors in examination of foreign policy of the First Czechoslovak Republic and its assessment were formed by the early 1960s, and with no significant changes lasted until dissolution of the Soviet Union. It is worth noting that the national historiography at that time significantly advances in studying various aspects of foreign policy of the First Czechoslovak Republic, namely Czechoslovakia–Soviet Union relations and events preceding the Munich Agreement and liquidation of the First Republic. However, the prevalent in Soviet science class approach, with all its significance, did not allow giving an unbiased assessment to the events of 1938, as well as to foreign policy of the interwar Czechoslovakia overall.
L’albero della conoscenza: la dialettica del mito eterno dell’uomo secondo Hegel
Authors: Barnaba Martina
Published: December 2020

This paper aims to investigate the dialectical nature of the myth of original sin as described by Hegel. For introductory purposes, I will briefly highlight the process by which Hegelian philosophy operates the translation from religious representation to concept, demonstrating how this reading is at the basis of the interpretation of the myth. Then I will analyze the functioning of the dialectical movements of the biblical episode of Genesis 3 within the Phenomenology of Spirit and the Lectures on the Philosophy of Religion, in order to discuss the issues of good and evil, innocence and guilt, will and arbitrariness. In this reconstruction the dialectic will emerge in its importance as a structure that permeates human consciousness as well as reality in general. In the specific case of the tree of knowledge, we will witness the concretization of this eternal conciliation of contradictions in two specific areas, which will be treated in the last section: the question of evil on the one hand, which will be demonstrated as a necessary negative element that triggers the dialectical movement itself, and the question of freedom on the other, which will appear as the result of the emancipation of the subject from the natural state in which he finds himself in the so-called "garden of animals".
Thermal excitations in SrAl12O19∶Pr3+
Authors: Lü Shao-Zhe  , Chen Bao-Jiu  , Huang Shi-Hua  , Wang Xiao-Jun  , Lu Li-Zhu  , W M Yen  ,   (1)Department of Physics and Astronomy,University of Georgia,Athens,GA  30602,USA; (2)Department of Physics,Georgia Southern University,Statesboro,GA  30460,USA;Department of Physics and Astronomy,University of Georgia,Athens,GA  30602,USA; (3)中国科学院激发态物理重点实验室，长春  130021
Published: December 2020

In this paper, we have studied the emission spectra from the thermally excited 3P1 and 1I6 states in SrAl12O19∶Pr3+.The ratio of the emission intensities of 3P1→3H5 and 3P0→3H5 transitions is applied to measure temperature. It is also pointed out that the thermally excited 1I6 emission plays an important role in decreasing the quantum efficiency of the 3P0 visible emission.
Lie symmetry and the conserved quantity of a generalized Hamiltonian system
Authors: Mei Feng-Xiang  ,   北京理工大学理学院,北京  100081
Published: December 2020

For a generalized Hamiltonian system, a new conservation law derived by using the Lie symmetry is studies. Firstly, the differential equations of the system are given. Secondly, the Lie symmetry under special infinitesimal transformations is studied. Thirdly, the theorem of Hojman is generalized to this system. Finally, an example is given to illustrate the application of the result.
A counterexample of Dirac's conjecture for a system with a higher-order singular Lagrangian
Authors: Li Ai-Min  , Zhang Xiao-Pei  , Li Zi-Ping  ,   北京工业大学数理学院,北京  100022
Published: December 2020

The extended canonical Noether identities derived from an extended action in the phase space for a system with a higher-order singular Lagrangian are formulated.Based on the canonical symmetries of generalized constrained Hamiltonian systems, a counterexample to a conjecture of Dirac is given. Using the canonical first Noether theorem and canonical Noether identities and the extended canonical Noether identities, we have shown that Dirac's conjecture fails for a system with a higher-order singular Lagrangian in which there is no linearization of constraint in our treatment.
Observers for a class of 3D continuous chaotic systems
Authors: Zhou  Ping  ,   重庆邮电学院非线性系统研究所，重庆  400065
Published: December 2020

In this paper the design of observers of a class of 3D continuous chaotic systems is discussed. Only using a state variable and its (first-and second-order) time derivatives, one can construct a control law to implement the synchronization between the investigated chaotic systems and its observers.
Graded heterojunction in AlGaInP compound semiconductors and its application to HB-LED
Authors: Liu Lu  , Fan Guang-Han  , Liao Chang-Jun  , Cao Ming-De  , Chen Gui-Chu  , Chen Lian-Hui  ,   (1)华南师范大学信息光电子科技学院金属有机化合物气相沉积实验室，广州  510631; (2)华南师范大学信息光电子科技学院量子电子研究所，广州  510631
Published: December 2020

A simple model of the graded heterojunction in ALGaInP compound semiconductors was introduced to analyze the energy band profile.We analyze the energy band profiles with the different grading ways but the same grading length,under the different doping densities.We analyze the effect of the different grading lengths on the surplus of the spike potential to the potential of the n region under the different doping densities.We analyze the effect of the graded heterojunction,finding it can improve the HB-LED (high-brightness light emitting diode)performance,and proved by the experiment.A graded heterojunction should be applied to HB-LED,based on this analysis.
Formation and structure of artificial opal based on the colloidal silica sphere
Authors: Li Ming-Hai  , Ma Yi  , Xu Ling  , Zhang Yu  , Ma Fei  , Huang Xin-Fan  , Chen Kun-Ji  ,   南京大学物理系固体微结构物理国家重点实验室，南京  210093
Published: December 2020

Highly monodispersed colloidal silica spheres in submicrometer sizes were synthesized by a chemical method.The sizes of silica spheres measured by transmission electron microscopy range from 200 to 600 nm in diameter, and its distribution standard deviation is less than 5%.Scanning Electron Microscopy images show that using selfcrystallization of the silica spheres, we have successfully obtained artificial opals with the three dimensional closepacked, facecentered cubic (fcc) silica matrixes. Reflection spectra study reveals that artificial opals show (111) directional photonic bandgap features.
Cavity mode matching analyses of end-pumped solid-state lasers
Authors: Shang Lian-Ju  ,   曲阜师范大学物理系，曲阜  273165
Published: December 2020

Cavity mode matching principles of end-pumped solid-state lasers are analyzed th eoretically.The analyses in this article can be important references for designi ng end-pumped solid-state lasers.
Unique characteristics of long-period fibre gratings fabricated by high-freque ncy CO2 laser pulses
Authors: Wang Yi-Ping  , Rao Yun-Jiang  , Ran Zeng-Ling  , Zhu Tao  ,   重庆大学光电工程学院，重庆  400044
Published: December 2020

In this paper, we report novel long-period fibre gratings (LPFGs) written by focused high-frequency CO2 laser pulses. A number of unique characteri stics of such a LPFG, such as stroin, temperature, bend, torsion and transverse-load, etc., are observed by experiment, for the first time to our knowledge. These uni que features are mainly due to the asymmetrical distribution of the refractive i ndex on the cross section of the LPFG induced by high-frequency CO2 l aser puls es. Based on these unique characteristics, we have proposed a novel bend-insensi tive LPFG sensor that could solve the problem of cross-sensitivity between bend and other measurements, a novel torsion sensor that can realize absolute measure ment of twist rate and a load sensor that can achieve simultaneous measurement o f transverse load and temperature using a single LPFG element.
Bound states of the Klein-Gordon equation with n-dimensional scalar and vect or hydrogen atom-type potentials
Authors: Chen Chang-Yuan  , Liu Cheng-Lin  , Lu Fa-Lin  , Sun Dong-Sheng  ,   盐城师范学院物理系，盐城  224002
Published: December 2020

Characteristics of the bound states of Klein-Gordon equation with n-dimensional scalar and vector hydrogen atom-type potentials have been studied,the exact solutions of bound states are obtained-The exact energy expressions and the normalized analytically wave functions for bound states are presented-Two recurrence formulas and some explicit expressions for lower power radial average values are also derived-
Adsorption of linear ethane molecules in MCM-41 by molecular simulation
Authors: Zhang Xian-Ren  , Shen Zhi-Gang  , Chen Jian-Feng  , Wang Wen-Chuan  ,   (1)北京化工大学化学工程学院，北京  100029; (2)北京化工大学教育部超重力工程研究中心，北京  100029
Published: December 2020

Grand canonical Monte Carlo method is used to simulate the adsorption of linear two-centre ethane molecules in MCM-41 of different pore sizes at different temperatures and a range of pressures.Beside the amount of adsorption, the local density profiles for the mass centre and methyl groups as well as the angle distributions simulated for the ethane molecules are used to explore microscopic and orientational structures of the adsorbate inside MCM-41. The results indicate that ethane molecules near the wall of MCM-41 prefer to lie on the surface both at 180 and 300 K, while the rest molecules exhibit a trend to be perpendicular to the wall,and the increase of temperature makes the molecules placed more randomly.In addition, the distributions show that the molecules in the vicinity of the centre are basically disordered even at a low temperature of 180 K.
A study on multiple filamentation of locally modulated laser beams
Authors: Wen Shuang-Chun  , Qian Lie-Jia  , Fan Dian-Yuan  ,   (1)复旦大学信息科学与工程学院光科学与工程系，上海  200433; (2)复旦大学信息科学与工程学院光科学与工程系，上海  200433;中国科学院上海光学精密机械研究所高功率激光物理国家重点实验室，上海  20180 0; (3)湖南大学计算机与通信学院通信工程系，长沙  410082;复旦大学信息科学与工程学院光科学与工程系，上海  200433
Published: December 2020

Based on the nonlinear Schrdinger equation,we have simulated the multiple filamentation of locally modulated laser beams,and found that for B integral smaller than some values the local modulations grow to form filaments mainly by drawing energy from that part of background beam;the evolution of two parts of local modulation are basically independent if they are sufficiently far away from each other.
PIC simulation of the transverse wave-breaking in laser wake-field
Authors: Xu Han  , Chang Wen-Wei  , Yin Yan  , Zhuo Hong-Bin  , Ma Yan-Yun  ,   国防科技大学理学院,长沙  410073
Published: December 2020

This paper focuses on the influence upon the structure of the wake-field and the production of hot electrons due to a finite-width laser of high intensity and ultra-short duration propagation through an underdense plasma. Under the action of lognitudinal and transverse pondermotive forces, the plasma density forms a horseshoe cavity which acts as a moving convex to make the laser pulse self-focusing. The wake wave front curvature increases with time until a transverse wav e breaking occurs which depresses the wave breaking limit of the electrostatic f ield. The decrease of transverse wave breaking pushes more electrons into the ac celerating phase region to be trapped by wake wave and decreases the maximum ele ctronic kinetic energy.
The reversal of spontaneous magnetization in high Tc superconducting π rings
Authors: Ling Jian  , Wang Ke  , Xie Fei-Xiang  , Ma Ping  , Yang Tao  , Wang Fu-Ren  , Dai Yuan-Dong  ,   北京大学人工微结构和介观物理国家重点实验室，物理学院，北京  100871
Published: December 2020

The reversal of spontaneous magnetization of a superconducting π ring under a pulse current injection has been thoroughly analyzed with the fourth-ordered Runge-Kutta method. We find that the reversals from negative to positive and from positive to negative will produce different pulse output with a periodic pulse injection and some certain parameters which can give a checkout of directions of the spontaneous magnetization as well as the phenomena of reversal under pulse injection.
The adsorption geometry of ethylene on the Ni (110) surface
Authors: Li Bo  , Bao Shi-Ning  , Zhuang You-Yi  , Cao Pei-Lin  ,   (1)浙江大学物理系,杭州  310027; (2)浙江温州师范学院,温州  315000
Published: December 2020

The favourite adsorption site of ethylene on the Ni (110) surface at high and low coverages was investigated by theoretical calculation. In the cluster calculations a partial optimization of adsorbate geometry has been carried out. At low coverage the ethylene molecule occupies approximately the midway between the short-bridge and atop sites. The C—C axes of molecules are almost parallel to the ridges and are offset in the direction, the angle of C—C axis with respect to the Ni surface plane is about 10°. The C—C bond length is 0151 nm. At a high coverage (05ML), ethylenes form a c (2×4) phase. The local adsorption sites of two ethylene molecules in a surface unit mesh are found to be quite similar to that at low coverage, but the C—C bond lengths are 0142 nm and 0142 nm, respectively.
Study on the 16O(p,pα)12C and 16O (α，2α) 12C knockout reactions according to the independent α-cluster mode l
Authors: Lu Xiao  , Sun Xiao-Jun  , Yang Yong-Xu  ,   广西师范大学物理与电子科学系，桂林  541004
Published: December 2020

According to the independent α-cluster model, the reaction cross sections and s pectroscopic factors of the reactions 16O(p,pα)12 C and 16O(α，2α)12C at the energies of 101.5,90 and 140 Me V have bee n calculated by means of distorted wave impulsion approximation. Reaction cross sections and spectroscopic factors calculated are in agreement with experimental data, and are better than the results by using shell model. This indicates that the independent α_cluster model can describe the mechanism of the reactions be tter.
First-principles calculation of the vacancy formation energies in LiAl
Authors: Chen Li-Juan  , Hou Zhu-Feng  , Zhu Zi-Zhong  , Yang Yong  ,   (1)厦门大学固体表面物理化学国家重点实验室,厦门  361005; (2)厦门大学物理系,厦门  361005; (3)厦门大学物理系,厦门  361005;厦门大学固体表面物理化学国家重点实验室,厦门  361005
Published: December 2020

The LiAl is a typical intermetallic compound which has many important applications. We have employed the first-principles pseudopotentials and the plane wave energy band method to calculate the vacancy formation energies of Li and Al vacancies in LiAl intermetallic compound as well as the atomic relaxations around the vacancies. The charge redistribution around the vacancies, electronic densi ty of states and their band structures are also discussed.
3ω method and its applications in nanomaterials and nanodevices
Authors: Feng Ping  , Wang Tai-Hong  ,   中国科学院物理研究所，北京  100080
Published: December 2020

3ω method has been investigated and its applications are analyzed. A wide appli cations in measuring the thermal conducti-vity and specific heat of material s are discussed. Here we discuss the mechanism of this method and introduce some basic applications. With some calculations in the two dimensional tunnel juncti on arrays and applications of 3ω method, a fast, primary Coulomb blockade therm ometer can be realized with a super-high precision in measuring temperatures in the Coulomb blockade regime.
Growth mechanism and Raman spectroscopic study of “interlinked-cone" shaped CNx nanotubes
Authors: Ding Pei  , Liang Er-Jun  , Zhang Hong-Rui  , Liu Yi-Zhen  , Liu Hui  , Guo Xin-Yong  , Du Zu-Liang  ,   (1)河南大学特种功能材料实验室,开封  475001; (2)郑州大学物理工程学院,郑州  450052
Published: December 2020

CNx nanotubes have been generated by thermal decomposition of ferrocene/xylene over cobalt powder at 780℃—940℃ in an atmosphere of N2, H2 and NH3 released from NH4Cl pyrolyzing at 300℃. The high-resolution transmission electron microscope (HRTEM) images show that the tubes consist of unusual “interlinked-cone". The catalytic growth mechanism of CNx nanotubes is discussed based on the formation energy of different structures. Raman spectroscopic studies show that the ID/IG ratio represents the crystallinity of the CNx nanotubes. The shift of the Raman band to higher frequencies confirms the nitrogen incorporation.
Phase transition of solid-liquid electrorheological system in flow percess
Authors: Zhao Xiao-Peng  , Gao Xiu-Min  , Gao Xiang-Yang  , Gao Dan-Jun  ,   西北工业大学电流变技术研究所,西安  710072
Published: December 2020

Considering the short-range interaction of multi-particles, we have employed the equivalent plate conductivity model to simulate the phase transition of solid-liquid electrorheological(ER) fluids in flow process. We also devised experiment to observe the phase transition of ER fluids. The conclusions show that under the certain pressure the ER fluids begin to flow, here the flow is the two-phase flow. But when the strength of external electric field reaches a certain threshold value, the particles in ER fluids stop flowing, so the flow of ER fluids changes into one-phase flow, the phase transition happens. The phase transition observed in our experiment complies with the simulation fundamentally. The threshold strength of external electric field increases with the increasing pressure, and decreases with the concentration of particles in ER fluids.
Equilibrium optimization code opeq and results of applying it to HT-7U
Authors: Zha Xue-Jun  , Zhu Si-Zheng  , Yu Qing-Quan  ,   中国科学院等离子体物理研究所,合肥1126信箱  230031
Published: December 2020

The plasma equilibrium configuration has a strong impact on the confinement and MHD stability in tokamaks. For designing a tokamak device, it is an important issue to determine the sites and currents of poloidal coils which have some constraint conditions from physics and engineering with a prescribed equilibrium shape of the plasma. In this paper, an effective method based on multi-variables equilibrium optimization is given. The method can optimize poloidal coils when the previously prescribed plasma parameters are treated as an object function. We apply it to HT-7U equilibrium calculation, and abtain good results.
Compensation for the demagnetizing field in remanence measurements of perpendicular magnetic recording films
Authors: Feng Jie  ,   上海交通大学微纳米科学技术研究院，上海  200030
Published: December 2020

It is necessary to compensate for the demagnetizing field in remanence measurements of perpendicular magnetic recording films.In this paper,a new method of compensating for the demagnetizing field is proposed and an effective reverse field Heff is used to evaluate the dc demagnetization remanence curves,isothermal remanent magnetization curves,and the ΔM plots for perpendicular magnetic recording films.The demagnetization factor N is important for this method,and three methods are used to estimate the value of N. The results of the ΔM plots indicate that the intergranular interactions in Ba ferrite films seem to be of exchange coupling,while those in Co-Cr-Ta films are of magnetostatic interactions.
Measurement of hyperfine structure spectrum in 56908 nm line of 141Pr+
Authors: Ma Hong-Liang  , Lu Jiang  , Wang Chun-Tao  ,   上海大学物理系，上海  200436
Published: December 2020

Hyperfine structure spectrum in 56908nm line of 141Pr+ was measured by the collinear fast-ion-beam laser spectroscopy- All the spectral lines were resolved- The magnetic dipole and electric quadruple coupling constants, and hyperfine splitting of the metastable levels and excited levels were determined- Our results were in agreement with the published data within experiment uncertainty- The accuracy of the magnetic dipole coupling constants was improved by one order of magnitude compared with the published data-
Theoretical study on dielectronic satellites to the highly charged Nelike Eu resonance lines
Authors: Dong ChenZhong  , Fu YanBiao  , Xie LuYou  , Li PengCheng  , Ding Xiao  Bin  ,   西北师范大学物理与电子工程学院，兰州  730070
Published: December 2020

On the basis of the calculated wavelengths and intensities of n=3→2 transition in Nelike,Nalike and Mglike ions of Eu,and by considering the broadening of individual lines and overlapping of a large number of lines in plasma,we have simulated the spectral structure of n=3→2 resonance transition in Nelike ions and all of the dielectronic satellites transitions of Nalike and Mglike ions of Eu.Also the contributions from highn dielectronic satellites to the resonance line is considered and calculated.Compared with a few existing experimental results,the dielectronic satellite wavelength of 3s—2p transition shows a good agreement with experimental result.
Gravitational relation of prolongable general relativity in the irreversible process of a dissipative system
Authors: Li Zong-Cheng  ,   苏州大学东校区302信箱，苏州  215000
Published: December 2020

The heterogeneity h（ρt）and coarse-grained entropy S（ρtε）of the density distribution ρ in phase space and the derived computational expression of multiscale factor η* are used in the expansion of Weyl curvature into multiscaled curvature R*; and the multifractal in relation to the singular distribution of physical quantities on geometry is used in the preliminary establishment of the multifractal geometry of growing structures set in Riemann space; on this basis, the equation of non-conservative attractive field is set up by the introduction of the general dimension Du in relation to the fractal and informational and incident dimensions. The analysis here shows that the new result could render the suitable basis for the settlement of the questions such as the singularity of cosmology the unidentified matter in the cluster of galaxies, the doubt of information from black hole and the unification between gravitation theory and quantum physics, and so on.
Microstructure characteristics of Cu31.4%Mn alloyunder laser rapid solidification condition
Authors: Yang Sen  , Su YunPeng  , Huang Wei  Dong  , Zhou YaoHe
Published: December 2020

Laser rapid solidification experiments have been performed on Cu31.4%Mn alloy to investigate the response of microstructure pattern and cellular spacing selection to the variation of growth rate.With increasing growth rate,microstructures go from light band to elongated cell,regular cell,then elongated cell and planarlike structure,and finally to absolute stability planar in turn.Experimental results show that there is a distribution range in cellular spacing under the aser rapid solidification condition,the distribution range and the average spacing decrease with the increase of the growth rate.The maximum,λmax, minimum,λmin,and average primary spacing,A,as functions of growth rate vs, can be given by λmax=682v-033s，λmin=289v-028s and =435v-031s,respectively.The experimental results are compared with the HuntLu numerical model for rapid cellular/dendritic growth,and a reasonable agreement is found.
Effects of quantum electromagnetic dynamics in a cylindrical ring cavity
Authors: Jiang Wei-Zhou  , Fu De-Ji  , Wang Zhen-Xia  , Ai Xiao-Bai  , Zhu Zhi-Yuan  ,   中国科学院上海原子核研究所核物理室，上海  201800
Published: December 2020

A charge-free conductor cavity has macroscopic quantum effects that can be explained by the physical picture of vacuum zero-point energy. This paper studies the macroscopic quantum effects in the conductive cylindrical ring，in terms of zero-point oscillating modes. The zero-point oscillating modes are obtained through solving the Maxwell equations without sources under the boundary condition of the cylindrical conductor surfaces. The vacuum energy (i.e. the Casimir energy) per unit length and area for the double-layer concentric cylindrical ring is obtained and it can be decomposed into the three independent and convergent parts that come from the interior, exterior cylindrical surfaces and the portion between them, respectively. For an n-layer cylindrical ring, its Casimir energy comprises of (2n-1) parts， all of which are convergent. Topologically, the geometric structure of the cylindrical ring is analogous to that of the parallel plates. However, the Casimir energy of the cylindrical ring has the non-trivial property that the coefficients of the Casimir energies and potentials vary with the interval between the cylindrical surfaces, compared to the constant coefficient for the parallel plates. This non-trivial property will give rise to an additional Casimir force that does not exist in the case of parallel plates.
Limit cycle oscillating and chaos of the radiation field in a traveling wave tube amplifier
Authors: Hao Jian-Hong  , Ding Wu  ,   (1)北京应用物理与计算数学研究所，北京  100088; (2)中国工程物理研究院研究生部，北京  100088；石家庄师范专科学校物理系，石家庄  050801
Published: December 2020

In this paper the evolution of the radiation field from frequency bifurcation to chaos and the temporal and frequency characteristics of the nonlinear unsteady states are investigated, based on the threshold analysis of nonlinear instability for the radiation field in a traveling wave tube amplifier. In the soft nonlinear regime,the nonlinear radiation field is characterized by limit cycle oscillations with frequency bifurcated, and the output power spectrum is discrete and asymmetric around the carrier frequency. This instability is intermittent so that the device can operate in expected steady states or limit cycle oscillation states by slightly adjusting the parameter. In the hard nonlinear regime in which the radiation field is characterized by randomly non-periodic oscillations with frequency chaos, the output power spectrum is continuous and wide, the components with a larger amplitude are restricted in the low-frequency range near zero. This instability is continuous so that it cannot be avoided by slightly adjusting the parameter.
Study on characteristics of helix-type traveling wave tube filled with plasma
Authors: Xie Hong-Quan  , Li Cheng-Yue  , Yan Yang  , Liu Sheng-Gang  ,   (1)电子科技大学高能电子学研究所，成都  610054; (2)西南科技大学理学院，绵阳  621002;电子科技大学高能电子学研究所，成都  610054
Published: December 2020

A helix-type slow wave structure filled partially with plasma is immersed in a strong longitudinal magnetic field.By means of sheath model and linear field theory，the dispersion relation of the slow wave structure is derived. Hybrid modes which are formed at frequencies at which the phase velocities of electromagnetic and electrostatic waves coincide are found.The trend of change for disperstion characteristic,interaction impedance and gain is analyzed in detail in the cases of various densities of plasma and filling radius by numerical computation. Some useful results are obtained on the basis of the discussion.
The anisotropic phenomena in the D5d minima for the T1uhg Jahn-Teller system
Authors: Qiu Qing-Chun  ,   汕头大学医学院物理与信息学系，汕头  515031
Published: December 2020

Jahn-Teller (JT) systems contain typically a set of mutually equivalent energy minima in the lowest adiabatic potential energy surface. When one electron occupies the three degenerate electronic states in C60 molecules, the electronic states with a symmetry of T1u and the five degenerate vibrational states with a symmetry of hg will be interacted and form the T1uhg JT system. When the non-linear vibronic interaction is considered, the JT system will contain the D5d minima and D3d maxima, and vice versa. In this paper, on the basis of unitary shift transformation, the modified scale transformation is introduced and the anisotropic phenomenon is studied in the D5d minima for the T1uhg JT system. The results are incorporated into the expressions for the states in the D5d wells and their associate energies. The symmetries and their corresponding energies in the D5d wells in the electronic space are obtained. For finite couplings, the phonon overlap between wells and inversion splitting are also studied. The results obtained in this paper not only show that the anisotropic effect has a significant influence on the above physical quantities, but also are of interest in the studies of anion states (C-60) of the C60 molecules and other C60 anion-related materials.
Theoretical analysis and numerical calculation for the transmission spectrum of long-period fiber gratings with a rectangular index modulation
Authors: Xu Xin Hua  , Cui Yi Ping  ,   东南大学电子工程系,南京  210096
Published: December 2020

In this paper, we present a theoretical method to analyze the spectral characteristics of long-period fiber gratings (LPGs) with a rectangular index modulation. Furthermore, we numerically calculate the transmission spectrum of a long-period grating written in Corning FlexcorTM 1060 fiber. The calculation results agree with the experimental results.
Effect of Dietary Cation-Anion Difference on Milk Composition and Blood Mineral Status of Peripartum Buffaloes
Authors: Patel R. N. , Lailer P. C. , Vipin . , Soni P. K. , Kumar K. , Bhardwaj S.
Published: December 2020

This study aimed to determine the effect of diet formulated to provide prepartum (DCAD= -749.16 mEq/head/day) and postpartum (DCAD = 1473.56 mEq/head/day) by feeding 90 g of an anionic and 120 g cationic salt respectively, on blood mineral concentration, health, postpartum milk production and composition in buffaloes. Twenty multiparous buffaloes were enrolled 21 days before expected calving date and divided into two groups. The treatment group with 10 cows received anionic rations for - 21 day to parturition and cationic ration from parturition to +21 days, while the control group was fed a usual ration. Postpartum incidences of milk fever, dystocia, retention of placenta, mastitis as well as weekly data of milk production, and milk composition were recorded. Plasma samples obtained at days -21, -10, -1, +1, +10 and +21 relative to calving were analyzed for calcium and magnesium. Magnesium concentration was increased with reduced prepartum Dietary Cation-Anion Difference (DCAD) in the diet value being 2.77±0.13 mg/dl and 3.15±0.12 mg/dl for the control and treatment group respectively, one day before calving. Calcium concentration was significantly higher (P<0.05) just one day before calving and it further higher (P<0.001) at 1, 10 and 21 days after calving in the treatment group as compared to the control group. Considerable reduction in per cent incidence of parturient paresis (10.0 vs. 20.0), and prolapse (0.0 vs. 10.0) was observed treatment group as compared to the control group. The DCAD concentration had no effect on milk yield, protein, lactose and fat corrected milk, but postpartum milk fat was significantly increased by the treatment. It may be concluded that by altering DCAD of the diet can increase postpartum milk fat with benefits in calcium status and reduced disease incidence without negatively affecting performance in periparturient buffaloes.
An on Farm Trail and Front Line Demonstration on Management of Pod Borer Complex in Pigeon Pea
Authors: Ratnakar V. , Veeranna G. , Shiva B. , Singh K. Anand , Rao P. Jagan Mohan , Reddy P. Raghurami
Published: December 2020

The study was undertaken on management of pod borer complex in redgram, Cajanus cajan by erecting of pheromone traps for monitoring of Helicoverpa armigera @ 4/ac. Spraying azardiractin 1500 ppm @ 5ml/ l, two sprays with 10 days interval during flower initiation stage. Spaying of Bt @ 2g/l at 25 per cent flowering stage of the crop followed by need based application of emamectin benzoate 0.4 g/l at flowering and pod formation stage was done in 5 locations for an on farm trial and 10 locations for front line demonstration in Bhadradri Kothagudem district of Telangana State during Kharif 2018 and 2019, respectively. The cost benefit ratio (BC Ratio) was higher in technology demonstrated plots with 2.5:1 and 2.3:1 whereas BC ratio was lower comparatively in farmers practiced plots with 1.8: 1 and 1.9:1 in corresponding Kharif 2018 and 2019.
Use of Origanum vulgare Essential Oil as an Antibacterial Additive in the Preservation of Minced Meat
Authors: Heni Sonia , Boughendjioua Hicham , Saida Meliani , Bennadja Salima , Djahoudi Abdelghani
Published: December 2020

The essential oil extracted by hydrodistillation from the aerial parts of Origanum vulgare L. harvested in the region of Skikda (North-East-Algeria) gave an excellent oil yield (2.8%). Its analysis by Gas Chromatography–Mass Spectrometry (GC/MS) identified 98.10% of its constituents. The major components are: carvacrol (47.6%), thymol (16.6%), p-cymene (13.5%) and γ-terpinene (11.2%).

The aim of this study was to the preservative effect of Origanum vulgare essential oil applied to a very low concentration of 0.025% (minimum inhibitory concentration (MIC)), of a sensitive food of essential nutritional value, of great consumption and easily perishable “minced meat”, stored at different times, namely: T0 = 0 min, T1 = 40 min, T2 = 24 h, and T3 = 48 h. By studying its microbiological quality by determining the rate of reduction of the total aerobic mesophilic microflora and of Staphylococcus aureus. The addition of Origanum vulgare essential oil to minced meat allowed a highly significant reduction of 0.01<p<0.1 in total aerobic mesophilic microflora reduction rate and very highly significant (p≤0.01) for Staphylococcus aureus, and markedly increase the shelf life. This allows us to propose the use of this essential oil as a source of natural preservative substances.
RP-HPLC-PDA Method Development, Validation and Stability Studies of the Novel Antineoplastic Drug Combination - Decitabine and Cedazuridine
Authors: Ishaq B. Mohammed , Reddy L. Siva Sanker , Venu S. , Sreenivasulu M. , Prakash K. Vanitha
Published: December 2020

Aim: The aim of our present work was to develop and validate a reverse phase high-performance liquid chromatography (RP-HPLC) method for the simultanious determination of Decitabine (DEC) and Cedazuridine (CED).

Methodology: The developed method was further applied to observe the degradation of analytes under the influence of different forced degradation conditions. Analytes were resolved on C18, 250 x 4.6 mm, particle size 5 µm Xterra column, using a mobile phase combination of 0.1% Ortho Phospharic Acid buffer pH 6.5: Methanol (40:60v/v) with flow rate of 1mL/min and injection volume of 10 µL. Quantification was carried out with PDA detector at an isosbestic point of 220 nm with a linear calibration curve in the concentration range of 35-175 μg/mL for DEC and 100-500 μg/mL for CED.

Results: Validation of the developed method was performed as per ICH guidelines viz., linearity, accuracy, precision, and robustness. The limits of detection (LOD) and the limits of quantification (LOQ) for CED were found to be 2.69 µg/mL and 8.15 µg/mL respectively. LOD and LOQ for DEC 1.55 µg/mL and 4.68 µg/mL respectively. Moreover, validated method was applied to study the degradation profile of analytes under various stress degradation conditions.

Conclusion: The proposed method was found to be sensitive, specific and was successfully applied for the simultaneous estimation of Decitabine (DEC) and Cedazuridine (CED) in bulk drug, and tablets.