bluuebunny/crossref_metadata_2025 huggingface dataset:
Grade 2 students’representation of mathematical ideas on multiplication through open approach and lesson study
Authors: Pawattana Aree , Prasanphanich Supaporn , Kanhapong Aukkarawut , Chanthes Pana-anong
Published: April 2021

The objectives of this research were 1) to analyze students’ representation of mathematical ideas 2) to study students’ learning ability in Open Approach and Lesson Study class by specifying criterion in the learning achievement test on the title “multiplication (1) that was not less than 75% of the total number of students pass 75% of full score. The target group of this research were 42 students of grade 2/1 of The Demonstration school Primary level ( Mardindang) Khon Khaen University, Khon Kaen Province.This research was one short case study design. Students were tested one time after finishing learning Unit. The instruments used for data collection were 1) 6 Multiplication (1) learning lesson plans 2) learning achievement test of multiplication (1). Learning achievement results were analyzed by comparin g with specified criterion as average and percentage. Students’ representation of mathematical ideas were analyzed from note recording, VDO recording, teaching recording, and students’ worksThe results revealed that : 1) 95.23% of total number of students obtained score passing criterion 75% of full score. 2) Students showed 5 ways of the representation of Mathematical ideas which were following 2.1) Material manipulation, students used wooden blocks to represent the ideas so that they could find the answer. They understood the meaning of group and element by grouping the amount of element. 2.2) Using pictures, Students drew a picture of blocks, squares or diagrams. They drew pictures as elements equally of each group to represent the way to find the answer. 2.3) Speaking, Students explained verbally how to count equally, how to add repeatedly and recite the multiplication table. 2.4) Writing, Students wrote the numbers as repeated addition. They wrote the amount which increased equally. They explained the amount of equal element of each group. Moreover, they wrote the mathematical sentence of addition and multiplication. It was noted that the multiplicand was amount of group and the multiple was elements of group. 2.5) Using real situation, Students shared their own real life experiences that was connected coherently with the mathematical problem given by the teacher. They also explained their ideas by using mathematical symbol of multiplication to show how to get the answer.
Students’ conceptual understanding of natural resources in geography through research-based learning
Authors: Suthanakiattikan N , Tupsai J , Yuenyong C
Published: April 2021

The purpose of this study was to explore grade 7 students’ conceptual understanding of natural resources taught in geography through research-based learning. The samples were 34 students in grade 7 of Khon Kaen Demonstration Secondary School, Khon Kaen Province. The interpretive method was used to analyze students’ conceptual understanding of natural resources collected from students’ presentation of the concept map as conclusion in the final stage of research-based learning approach. The lessons of natural resources, including soil, water, forest, and mineral were used to examine how students construct their conceptual understanding in the form of ‘concept map.’ Data were interpreted through the rubric scoring with three criteria as follows. Level 1 was given to students who could draw a concept map describing at least 1-2 natural resources in Thailand with readable handwriting in colors. Level 2 was given to students when they could draw a concept map describing at least 2-3 natural resources in Thailand with readable handwriting in colors showing their creativity. Level 3 was granted to students when they could draw a concept map describing at least 4 natural resources in Thailand 4 with readable handwriting in colors showing their high creativity. This study also proposed the guidelines to enhance students’ conceptual understanding of geography through research-based learning.
Design steps toy car for STEM to STEAM Education learning in Chiang Mai Rajabhat Demonstration School
Authors: Boonchom Kritsada
Published: April 2021

The objectives of this study were designing a set of “Toy car” learning activity on the basis of STEM education and improved set of STEM activity. Development of a set of STEM activities was executed according to the engineering process. From the experiment and studied relate theory, the results were manual for teaching and student activity training. It was analysed Index of Objective Congruence (IOC) results found that STEM learning activity package was correct in content, learning activities and suitable for the purpose. The activity was tested by used to learning management with grade 5 and 6’s students in CMRU demonstration school. It found that the students’ satisfaction level toward STEM process was at a “good” level. It has value of 4.11 + 0.71 The STEM activity was improving to STEAM. It was presented in teacher training and found that the participants ’ satisfaction level toward STEAM process was at a “good” level. It has value of 3.98 ± 0.54 Participants, 89.60 % were confident that arts can be integral with science mathematics and this activity can be used to improve 21st century learning skills.
Local-based lesson on hydrologic cycle with environmental education integration: Designing learners ideas through STEM
Authors: Tadena Maria Theresa G. , Salic-Hairulla Monera A.
Published: April 2021

Seeing STEM education in a new light that seeks in helping learners use the local environment as a vehicle for developing understanding on various environmental issues. Providing adequate STEM and environmental education will make everyone appreciate their relationship with the environment which lead to environmental awareness and in developing a sustainable future. This study aimed to develop a local-based lesson on environmental education. Local-Based Lesson on Environmental Education was developed for integration to science lessons among grade 8 learners and was designed in a meaningful way that the integration process would just blend smoothly. STEM education strategies are utilized and applied by the learners in performing the activity embedded in the developed local-based environmental lesson. Through this, it developed the learners’ capacity in bringing their role as solution makers towards the pressing environmental issues in their local community. Using STEM strategies the learners have shown positive response to the developed lessons and were able to provide and design possible solutions in addressing local environmental isues. This implies that the application of STEM strategy in learners’ activity have developed the learners creative ideas in addressing environmental issues in their own community and improved their STEM knowledge and skills.
Innovation lesson plan of fertilizer dilemma story for integrated knowledge practicing through Lesson Study
Authors: Horasirt Yupaporn , Taylor Peter Charles , Yuenyong Chokchai
Published: April 2021

The paper clarified the developing lesson plan of fertilizer dilemma story for integrated knowledge practicing through lesson study. Through the PD program using lesson study, the theoretical framework of dilemma story was adopted to reference of the developing lesson plan. Methodology regarded paradigm. Participants included primary school teachers as team teachers, supervisors, expertise university lecturer, and school director. The primary school teachers as team teachers include a science teacher, a mathematics teacher, a technology teacher, and an art teacher in Nongsonghong district, Khon Kaen, Thailand. The developing lesson plan of fertilizer dilemma story for integrated knowledge practicing through lesson study will be interpreted through document analysis and participant observation. The innovation lesson plan of fertilizer dilemma story for integrated knowledge practicing could be summarized through the outcomes of lesson study design – plan, see, and reflect. The results provided the overview of the lesson plan of fertilizer dilemma story for integrated knowledge practicing that could be viewed through the structuring questions for ethical dilemma fertilizer story and example of dilemma story chemical fertilizer. This study may have implications for development program for integrate the curriculum in Thailand.
Designing “Saving Pig” STEM activity for Vietnamese primary schools
Authors: Nam Nguyen Danh , Hieu Le Trung
Published: April 2021

The paper presents teachers’ STEM education skills as well as teachers’ and students’ awareness of STEM education at primary schools. The research has concentrated on investigating potentials of STEM education and integration approach in teaching mathematics at primary schools. We also designed and organized “Saving Pig” STEM activities that integrated knowledge of mathematics, sciences, technology and other social science subjects. The research results have shown that STEM approach is appropriated for primary education. Our teaching strategies have also made a contribution to develop teachers’ STEM education skills and raised students’ interest for learning.
Organizing experiences - based learning activities “making bio-products for environmental protection” in STEM Education in high schools
Authors: Nguyen Hang Thi , Luong Van Thi Thuy , Pham Tu Thi Hong , Nguyen Ha Thi
Published: April 2021

STEM experience-based learning from practical problems will develop students’ skills and arouse their passions for exploring and learning the world. The theoretical research method was used to determine the relationship between experience-based learning and STEM education. Pedagogical experiments on STEM experientical learning activities with the topic “Making bio-products for environmental protection” in high schools are related to students’ awareness and skills of practical problem-solving, introduced through the plan to organizing STEM experientical learning activities; The survey method is used to produce results about students’ attitudes and behaviors against positive and negative actions with environment. The paper may have implications for developing organizing experience - based learning activities in STEM education.
The innovative lesson study for enhancing students’ mathematical ideas about addition and subtraction through open approach
Authors: Woranetsudathip Naphaporn , Yuenyong Chokchai , Nguyen Tien-Trung
Published: April 2021

The paper aimed to clarify the innovative lesson study learning activities of “how many and how many”. The activities provided concept of mathematical addition which were developed through open approach. The development of initiative the innovative lesson study learning activities on mathematical addition was processed based on Lesson Study. Methodology regarded interpretive paradigm. The understanding of innovative learning activities was developed through the activity of lesson study. The tools of interpretation included participant observation, reflection of lesson study teachers, and developing lesson plan document. Through this process, the learning activities could be clarified in this paper. The highlight of learning of activities included 1) making 5 and 6 from the Opaque and translucent double slit box (OTD box), 2) making 7 from playing 2 dices for 7 times, and 3) Making ten from the two slits box. The paper will discuss more about these three activities. These activities may have implications to mathematical teaching through open approach for primary school students.
Development of Learning Skills by Using a Computer Assisted Instruction on Problem Solving with Equations to Enhance Critical Thinking Skills of the Fifth Grade Students
Authors: Paengtip Pannee , Paengtip Sittichai , Dermrach Praewsree
Published: April 2021

The purpose of this study was to develop a computer assisted instruction about problem solving with equations to enhance critical thinking skills of the fifth grade students. Two phases were undertaken in the study. The first phase aimed to develop and monitor the quality of the CAI in which five experts on design and CAI were the main group to evaluate it. The second was to test and evaluate the CAI in which 30 fifth grade students within Bankotabaru School in Yala province were the main participants. The data collected within the first academic term of 2017 in Thailand were analysed using descriptive statistics, such as percentages, means, standard deviations, and t-test.

The results were that the CAI aiming to enhance critical thinking skills of the students were divided into 3 parts; 1) an introduction; 2) teaching processes; and 3) an evaluation. There was a higher percentage of critical thinking skills of the participants in association with before and after the use of the CAI at 52.18 and 80.41 with the difference value of 28.23 and the statistical significance of 0.05 level.
Utilization of stellarium-based activity: its effectiveness to the academic performance of Grade 11 STEM strand students
Authors: Acut Dharel P. , Latonio Rhett Anthony C.
Published: April 2021

This study was carried out to understand and bring to fore if a simulation-based activity is effective on the academic performance of the students which has a general outlook to enhance meaningful science learning. This study focused on effectiveness of the stellarium-based activity on the academic performance of Grade 11 STEM Strand students of Sotero B. Cabahug FORUM for Literacy, School Year 2017 – 2018. The respondents of this study were composed of 28 students. The data pointed out that data analysis results shows that by conventional criteria, the differences of the scores on the different competencies is considered to be extremely statistically significant Results revealed that the stellarium-based activity is effective in teaching the cycles of the sky. Statistical results showed that the academic performance of the respondents improved when taught using the stellarium-based activity. Thus, it is best to learn astronomy using simulations. Computer simulations have demonstrated the potential to facilitate this process by highlighting students’ misconceptions and presenting plausible scientific conceptions. From the results, students are recommended to use stellarium, where the process often involves open-ended investigations into a question or a problem, requiring them to engage in evidence-based reasoning and creative problem-solving, as well as problem finding. Furthermore, science educators are encouraged to use stellarium in teaching the cycles of the sky and as anchors of the future teachers must always come equipped for these challenges charged on them, thus engaging students to learn and develop the potentials needed from them to take part for the betterment of today’s world. Most importantly, future researchers are commended the development of a localized stellarium-based activity will greatly affect the academic performance of the student will surely boost their interest in learning astronomy education.
Meta-Analysis of STEM Education Approach effected on Student’ Creative thinking skills in Thailand
Authors: Monsang P , Srikoon S
Published: April 2021

The objective of this research synthesis is to synthesize research about STEM Education Approach effected on students’ creative thinking skills in Thailand. Period of published research papers from 2010 until 2019 in education field. The related literatures used in this study were chosen from Thai Digital Collection and Thailand Library Integrated system by using the meta-analysis research method. The research tool used was the synthesis record form. Research results can be summarized as follows; They are 10 STEM Education researches, were frequency published in 2017 (80%), the most researchers were female who studied in master degree of Science Education at Rajabhat Mahasarakham University. The most research objectives were about to study and to compare achievement and creative thinking skills of students by using STEM instruction model with Science content. The most research instruments were lesson plans and creative thinking skills measurement form. The most samples were purposive sampling of lower secondary school students with experimental research design. The effect size (d) of research = 0.307 indicating that the STEM instruction model has a positive impact on students’ learning achievement more than control group.
Research synthesis of STEM Education approach effected on students’ problem solving skills in Thailand
Authors: Khamngoen S , Srikoon S
Published: April 2021

STEM education integrates concepts that are usually taught as separate subjects in different classes and emphasizes the application of knowledge to real-life situations. A lesson or unit in a STEM class is typically based around finding a solution to a real-world problem and tends to emphasize problem solving abilty. So, the objective of this research is to synthesize research about STEM Education Approach effected on students’ problem solving skill in Thailand. Variables consisted of a unit of variable which included 17 variables. The collecting data tool is adjusted from the recording data form of the Office of Education Council in Thailand. Data were analyzed by frequency and percentage and were showed the result of STEM Education effected to problem solving skill analysing by one sample t- test, criterion and growth score for content analysis. The results showed that STEM Education Approach effected on students’ problem solving skills in Thailand research dated by 2009-2019 were published mostly in 2017. Naresuan University did the target research highest frequency. Researchers from Curriculum and Instruction, Early Childhood Education, Sciences Education, and Education major mostly produced the research and worked at the Office of the Basic Education Commission. Female reseachers did the more research in STEM Education than male.Thesis in Master degree was done the most comparing with dissertation in Doctoral Degree. Common research objectives mostly focused on “study”. Experimental design was found mostly especially in one group pretest-posttest design. Sampling method was found the most in Purposive sampling. Frequent sample found was students and followed by teachers and expert. Upper secondary level was mostly found in Educational level of sample. The subject area found the most was Physics and followed by Biology. Lesson plans were mostly used in research instruments and analyzing methods mostly used descriptive statistic. The result of STEM Education effected to problem solving skills using one sample t- test found that students’problem solving skills mean score in the post-test were higher than that in the pre-test after learning by STEM Education approach at both the 0.01 and 0.05 level of significance relating to the analyzing method by using mean and standard deviation and growth score.
Factors and Needs Assessment of Hyflex Learning with Science Activity Base For Strengthen Critical Thinking
Authors: Jongmuanwai Benjapuk , Simmatun Pawit , Teemueangsa Sanit , Jedaman Pornchai
Published: April 2021

This article aimed to analyzed the factors of Hyflex learning with science activity base for strengthen critical thinking.This mixed method research on the qualitative research and quantitative research both to participatory action learning. The first to involved synthesizing documentary, interview with 20 teachers, and to collection data by questionnaire with 150 teachers and 150 students. The study revealed that the factors were to instructional using the students base, content transferal of technology to knowledge linking and communication, learning methods to anytime, accessing the technology for opportunity to continuous learning, experience arrangement and environment to diversity. And the needs assessment of Hyflex learning with science activity base for strengthen critical thinking of a level at high levels, The participants showed high needs regarding of students base (PNI Modified=.35) and technology transferal (PNI Modified=.33)
Food for Feeding Red-Whiskered Bulbul (Pycnonotus jocosus Pattani)
Authors: Pangsuban Sasithorn , Thavarorith Wipat
Published: April 2021

Food of an economic bird, Red-whiskered bulbul (Pycnonotus jocosus pattani), was investigated since November 2017 – August 2018 in yala province, Thailand. They were studied by applying survey method. The samples were the red-whiskered bulbul caretakers selected by convenience sampling. Deep Interview and rating scale questionnaires were used as research tools to find the kind of food for most likely tendency by average and percentages. The results showed that 98 percent of samples were male, their education level were undergraduate and lower. The average income was between 10,000 - 30,000 baht. The majority of food which the caretakers used for feeding their pet birds at different ages were the same. They were derived from plants 18 families, including 24 species. The main plants were Kluai Hin (Musa acuminata × balbisiana (ABB Group) ‘Saba’), Kluai Nahm Wa (Musa sapientum Linn.), papaya (Carica papaya L.), water melon (Citrullus lanatus (Thunb.) Matsum. & Nakai), tomato (Solanum lycopersicum L.), cucumber (Cucumis sativus L.), chinese squash (Luffa acutangula (L.) Roxb.) and Tam Lueng (Coccinia grandis (L.) J.Voigt,). Some insect such as mealworm (Tenebrio molitor L.), crickets (Gryllus bimaculatus), some species of grasshopper, and ant eggs were also provided. However, some caretakers mixed some supplements such as vitamins and chili curry into their food for feeding the mature pet bird. Meanwhile, honey and ready-made meals were only used into rearing their chicks.
Assessment of radon and heavy metals in drinking water from some areas of Ra-ngae District, Narathiwat Province, Thailand
Authors: Pisapak P
Published: April 2021

The presence of radon and heavy metals in water is considered as a potential threat to public health. This study aimed to estimate the health risk related to radon concentration and heavy metals in drinking water samples, which taken from in Kalisa sub-district of Ra-ngae district, Narathiwat province. Radon concentration was measured by a solid state nuclear track detector (SSNTD, CR-39). The measured values ranged from 0.17 to 7.63 Bq l−1, which is much below the safe limits proposed by the US Environmental Protection Agency (US EPA) and UN Scientific Committee on the Effects of Atomic Radiation. The mean annual effective dose calculated for these samples was also found to be within the limits provided by WHO and EU council. Three mineral water sources were also analyzed for concentration of certain heavy elements like As, Fe, and, Pb by using inductively coupled plasma-optical emission spectrometer, (ICP-OES). Out of these, concentrations of As were found to exceed the permissible limits suggested by WHO. However, safety limit of national standard for arsenic in drinking water remains at 0.05 mg l−1.
The Optimal Conditions of Saccharification and Fermentation Processes for ethanol production from Bagasse and Economic Feasibility Analysis
Authors: Sukkaew Adulsman
Published: April 2021

Thailand is one of the agricultural countries as a good natural resource like rice, sugarcane. The residue of sugarcane is a Bagasse as the main agricultural products of the sugar industry. Since Thailand is one of the major sugar exporters, it is reported that Thailand produces sugarcane bagasse over 50 million metric tons every year. The objective of this research was to study the optimal condition of saccharification and fermentation Bagasse converted to ethanol production. The research found that 7 days after saccharification and fermentation from Aspergillus and yeast has the highest ethanol content was 12.45±0.43%. While reducing sugar contents 285.65±0.74 g/L. And the results of ethanol concentration from the first and the second distillation were shown as 65.29±0.57% and 92.05±1.24%, respectively. When a study of economic feasibility analysis from selected ethanol condition process has a sensitivity analysis and the payback period is approximately only five months to seven months. In conclusion, the proposed project is attractive for the investors because the current price of ethanol is 18.21 THB per litter and its trend is expected to keep rising. However, if sugarcane bagasse was properly managed, it would be mean to support the robustness and sustainability of the community. It can also reduce agricultural waste and weeds. It can solve the energy crisis as an alternative avenue in the future.
Damage Behavior Prediction of Repaired Composite Laminates Subjected to Oblique Penetrate Loading
Authors: Yang Lingling , Ran Tao , Liu Zhihui , Ren Yiru
Published: April 2021

To predict the effect of oblique impact on the damage and performance of perforation resistance of repaired composite laminates, a three-dimensional continuum damage model (CDM) is used to simulate and calculate the low-velocity impact process of repaired laminates. In the established finite element model, several different types of failure modes are considered. The damage model is based on the modified 3D-Hashin failure criterion to predict the initial damage of the fiber and matrix. The linear-exponential law and the exponential law are used to simulate the tensile and compressive softening process of the material. The triangle traction-separation law and mixed-mode fracture energy method are applied to simulate interface debonding damage between patch/lamina, patch/patch and lamina/lamina. A comparison of the numerical results of several different offsets with the experimental results shows that the simulated failure modes and impact responses are very close to the experiment, which verifies the validation of the finite element model (FEM). The increase of the impact angle can enhance the residual velocity of the projectile in the laminate and reduces the energy absorption. At the same time, it has a great influence on the failure modes, especially the interface debonding damage of the patch.
Experimental Study on Dynamic Tensile Properties and Ballistic Performance of Different Armor Materials
Authors: Wu Hailing , Miao Cheng , Bai Lihong , Niu Haiyan , Zhong Tao , Lu Ruijiao , Yang Zizhen , Guo Yiyan
Published: April 2021

Hopkinson bar system was used to test the dynamic tensile properties of high nitrogen steel, 685 armor steel, 603 armor steel and 316 stainless steel by adjusting loading pressure, the strain rate and dynamic tensile strength of different armor materials were obtained. Under the experimental conditions in this paper, the dynamic tensile strength of the high-nitrogen steel is 1883 MPa which is the maximum of the four materials. At the same time, by using 12.7 mm armor-piercing projectiles, the ballistic tests of semi-infinite targets of different armor materials were carried out. Penetration depth of high-nitrogen steel is 25.5 mm which is the smallest of the four materials. The standard penetration depths of armor materials decrease with the increase of dynamic tensile strengths, and tensile strength increases under the test conditions in this paper. Therefore, the material with high dynamic tensile strength should be selected as the ballistic component in armor design.
Adiabatic Shearing Behavior of Shock-Prestrained Ti-2Al-9.2Mo-2Fe Alloy at Different Reloading Strain Rates
Authors: Ji Jianping , Li Zheng , Ren Yu , Tan Chengwen
Published: April 2021

The effect of shock-prestrain on the adiabatic shearing behavior of a metastable β titanium alloy, Ti-2Al-9.2Mo-2Fe (2A2F), is systematically investigated. 2A2F alloy blocks with average grain size of 67 μm were first shock-prestrained at 6 and 12 GPa, and then reloaded at strain rates of 3000 and 4000 s−1. The results show that, the dynamic strength of 2A2F hardly increases after the shock prestrain. Adiabatic shear bands (ASBs) are more likely to bifurcate and interact, and the density of micro-damages and micro cracks in ASBs increases in the shock-prestrained materials. This trend becomes more significant with the increased preshock stress amplitude. However, in general, the amount of ASBs is low regardless of shock stress amplitude. The dynamic ductility is also hardly affected by shock-prestrain. These suggest that 2A2F alloy has good resistance to multiple impacts.
Study on the Penetration Performance of Micro-shaped Charge with Different Liner Materials
Authors: Han Yangyang , Yin Jianping , Cui Hailin , Bi Guangjian , Duan Conghui , Zhang Yu , Li Hao , Qi Jiawen
Published: April 2021

In order to study the damage performance of micro-shaped charge with different materials, the AUTODYN finite element software was used to simulate the formation process of damage element and the penetration performance of micro-shaped charge to target when the liner material was copper, Teflon and nylon. The results show that although the head velocity of the damage element formed by the copper liner is the smallest, the penetration depth to the target is the deepest, and that of the nylon liner is the largest, but the penetration depth to the target plate is the smallest. The head velocity of the damage element formed by the Teflon material liner and the penetration depth to the target are between the two.
Study on Performances of Novel Anti-Detonation Composites
Authors: Wang Jinhua , Shi Xiumei , Wang Qiang , Zheng Yangsheng , Zhang Lijun , Cheng Yingye , Zhang Le
Published: April 2021

From the optimized wave-absorbed layer aspect, a new light weight anti-detonation composite structure composed of armor steel, Aluminum foam, ceramic, aramide fibers and rubber materials is produced, and detonation tests with 50 g RDX, 6 kg-TNT, 8 kg-TNT, 10 kg-TNT charge were carried out on it. The results show that new anti-detonation composite has the advantages of reducing blast peak value, prolonging the action time for shock wave and absorbing wave to decrease blasting energy. The anti-detonation composite component has high bearing strength and tensile strength; after the detonation test, there is no penetrated destruction and large deformation on the backing plate, which satisfies the NATO protection Standard level two and level three.
Effect of Coupling of Eletropulsing Treatment and Ultrasonic Surface Modification on the Surface Nanostructure Layer of Steel
Authors: Shen Yalin , Liu Dan , Tang Pengbo , Liu Jie , Zhang Shiming , Li Yong , Yan Fangjun
Published: April 2021

A coupling of eletropulsing treatment and ultrasonic surface modification (C-E-U) was employed to design the nanostructured layer materials with high strength and surface protection of 40Cr17Mo steels. The surface properties of the specimens after dry cutting, coupling of ultrasonic-eletropulsing treatment (CUE) and coupling of eletropulsing-ultrasonic treatment (CEU) were characterized, respectively. A grain refinement layer was formed on the specimen’s surface after the coupling of eletropulsing treatment and ultrasonic surface modification. The residual stress on the top surface was reduced. This is caused mainly by two aspects: one is the aggregation of subgrain boundaries during deformation in order to form new grain boundaries processed by the ultrasonic effect; the other is that the acceleration effect of electropulsing. Moreover, it was found out that electropulsing is very effective to release residual stress in the material surface.
Structure and Power Design of 80 mm Warhead
Authors: Duan Conghui , Yin Jianping , Qi Jiawen , Bi Guangjian
Published: April 2021

This paper mainly conducts numerical simulation and analysis of the warhead structure of 80 mm assault ammunition, which needs to realize the effective penetration of 400 mm into the C35 concrete target and carry out the killing of incoming bullets. Before the first level of warhead design: effective penetration level before the warheads main function is to 400 mm C35 concrete goals, to achieve tactical technique index by shaped charge, bar type jet formation, medicine type cover adopt ball is short of cover, material is copper, medicine cover type choose such as wall thickness, and wall thickness of 2.52 mm, dynamite to choose B, using Ls-Dyna software simulation. The results show that the structure design has good jet forming, which can easily penetrate the 400 mm C35 concrete target plate, and the opening diameter is more than 20 mm. Through the hole opening diameter of the front rank warhead, it is finally determined that the diameter of the incoming bullet is 20 mm and the killing force is effective.
Interlayer Material Interactions on Shaped Charge Jet Protection Performance of Passive Armor
Authors: Liu Yang , Li Rujiang , Zhou Pengfei
Published: April 2021

The process of jet interaction with oblique highly passive armor was analyzed, and the relations on energy absorbed by the interlayer material of inert cassette were presented. The bulging armors with silicon rubber and plexiglass interlayer material interacted with shaped charge jets were studied experimentally. When the jet parameters is determined, the energy deposited in the interlayer during shaped charge jet penetration is related with not only its physical dimension, such as obliquity and thickness, but also with other physical parameters, such as material density, sound velocity and material strength, et al. the shaped charge jet penetrating capability decrease 75% and 65% respectively when passed through the silicon rubber and plexiglass composite armor, which shows that the silicon rubber cassette have better protection performance.
Numerical Simulation of Wedge-shaped Multi-sandwich Reactive Armor Interfering with Shaped Jet
Authors: Hou Jiahao , Zhou Tong
Published: April 2021

In order to obtain the explosive reaction armor with better interference capability to jet, a king of wedge-shaped multi-sandwich explosive reaction armor was designed on the basis of the existing wedge-shaped and flat structure explosion reaction armor. ANSYS/LSDYNA was used to simulate the interference process of the wedge-shaped multi-sandwich reaction armor on jet. Focusing on the research on the interference effects of four kinds of explosive reactive armors on jet penetration at 0° and 68°, it is found that one of the new explosive reactive armors has better jet interference effect than the other three explosive reactive armors at the impact angle of 0°. And the new explosive reactive armor is obviously best than other explosive reaction armors when jet penetrate at an angle of 68°. Finally, the relationship between the interference effect of explosive reactive armors on jet and the penetration angle of the jet was studied.
Discrete Element Simulation of Brittle Porous Material Failure
Authors: Wang Zhu , Zheng Yuxuan , Zhou Fenghua
Published: April 2021

The study uses Particle Flow Code (PFC) 2D discrete element software to reproduce the dynamic compressive experiment of foam concrete, a typical brittle porous material, and to calibrate micro-parameters of hardened cement mortar, building a discrete element model of foam concrete. Experimental phenomena and inner mechanisms are further analyzed and studied, leading to conclusions in the deformation characterization, failure mode and failure mechanism of foam concrete specimens under different strain rate loading. The research results indicate that under low strain rate loading, the specimen cracks from inside evenly; the processes from failure to compaction is endoenergetic, resulting in stress plateau phenomenon and even deformation during the experiment. Under high strain rate loading, cracks are generated in an explosive manner at the impacted end, and the specimen on the whole is not damaged evenly. Simulation results basically fit the experiment data. The peak stress curve fitting of concrete foam from under quasi-static conditions to high strain rate is studied, which shows obvious strain rate effect that grows exponentially. By calculating models with different densities, it is found that the compressive strength of foam concrete increases along with the growth of density. Thus, PFC can be used in numerical simulation of dynamic mechanical properties of brittle porous materials.
Research on the Surface Performance of Copper after Siliconizing Treatment
Authors: Li Xiaojing , Yang Dongbiao , Xu Min , Yang Lihui , Gao Yongliang , Li Qingxiao
Published: April 2021

In order to improve the surface properties and extend service life of pure copper. Siliconizing of copper was carried out by penetrating silica powder. Three new phase were formed in layer, they are Cu0.83Si0.17, Cu9Si, and Cu6.69Si, respectively. The highest micro hardness of the layer reaches up to 340HV0.05, which is 5 times higher than the substrate. The corrosion resistance and oxidation resistance of copper after siliconizing in different solution were studied, such as, the corrosion resistance have improved 2.3 times in H2SO4 solution, 3.8 times in NaCl, and 4.4 times in artificial seawater separately. The oxidation resistance of the siliconized copper is 18 times than that of pure copper. The above experimental results show that, the siliconizing layer will improve the performance of pure copper dramatically.
Review on Quantum Communication and Quantum Computation
Authors: Chen Jiajun
Published: April 2021

Quantum communication has made great breakthroughs in recent years. Because of its characteristics for strict information security transmission and high speed, it has received attention from related research fields around the world. This paper briefly reviews the progress in the field of quantum computing and communication. The basic functions of quantum mechanics related to the quantum communication are first introduced, including qubit, logic gates, postulates, polarization and quantum entanglement. Then the applications of quantum communication are discussed including teleportation, cryptography and quantum networks. Finally, advantages and disadvantages for the current applications are analyzed and the challenges remained in the current research are demonstrated.
A Feature Extraction Algorithm Based on Structural Light in Sea-air Imaging
Authors: Jian Bijian , Ling Yongfa , Pen Ting , Mai Changli
Published: April 2021

The distortion phenomena in sea-air imaging mainly include geometric distortion, color deviation and low contrast. In order to obtain the target information accurately, it is of great significance to study the distortion image correction. More feature information can be obtained by using grid structured light. However, the random fluctuation of water surface and the complexity of underwater imaging environment, the traditional corner detection algorithm can not effectively obtain the correct corner information. In this paper, a fast corner detection algorithm based on minimum kernel value (MRSFAST) is proposed. The experimental results show that compared with the traditional detection algorithm, the algorithm can extract the feature point information of the image in real time, which is of great significance to further realize the distortion image correction.
An Easy-to-Array Respiration Sensor Based on Coupled Static Current Field
Authors: Zeng Minghui , Ren Xi , Liu Changlin
Published: April 2021

Respiration detection is an important detection method in the diagnosis and treatment of diseases in the future. A sensor device with respiratory dynamic characteristics sensing and chemical composition sensing will provide more information for respiration analysis. In this paper, a gas sensor based on a coupled electrostatic field and flow field is proposed. The sensor uses flow field drift and electrostatic field polarization and migration to achieve selectively separation and detection of charged droplets. This sensing principle ensures that the device has a faster recovery time than a device based on the adsorption, and is more suitable for the needs of respiration detection.
Research on Grid High Voltage Harmonic Detection Based on Ubiquitous Power Wireless Network
Authors: Guo Yun , Xu Minhu , Zhang Jian , Yang Li , Shen Yubo , Zhou Hongyi
Published: April 2021

The intelligent optimized operation of the power grid depends on the ubiquitous perception of the system and complete and correct data support, which is also the most basic requirement that the ubiquitous power Internet of Things perception layer must meet. In the application of ubiquitous power Internet of Things, obtaining complete and correct measurement data is the basis for managing power quality problems. However, in the entire link of the actual grid collection and transmission, data defects will inevitably occur. Based on the background of the ubiquitous power Internet of Things wireless network, the paper adopts the idea of modular programming and divides it into three modules: frequency measurement sampling, waveform display and harmonic display according to the performance indicators of the harmonic analyser. It can measure the frequency of the input AC voltage, perform AC synchronous sampling of the input voltage according to the measured frequency, and display the waveform of the input voltage; and then calculate the harmonics of each order through the FFT algorithm. The simulation found that the proposed control strategy significantly improved the harmonic current content than the traditional d-q positive and negative sequence decoupling control.
Analysis on Lightning Strike Breaking Defects of 500kV Yangdong Line II Optical Cable
Authors: Yang RunHua , Shu XinJian , Wu LiJie , Quan YiZhan , Liu HuiFang
Published: April 2021

The 500kV Yangdong Line II starts at Shanxi Yangcheng Power Plant and ends at Shandong Dongming Switch Station. It was completed and put into operation in May 2000, with a total length of 246.465 km. In this paper, through the field investigation and weather operation statistics, as well as the metal micro-analysis of the broken strand OPGW sample, it is concluded that the root cause of the broken strand is that the continuous current discharge process of the lightning channel can keep the arc root for a long time, which may cause ablation on the surface and even the inside of the single stranded wire. This paper also put forward measures to prevent such failures.
Research on driving current prediction method based on ARIMA
Authors: Zhou Yuan , Wei Guofu , Liu Yingnan , Zhang Guoxin
Published: April 2021

The abnormal driving current of DC measuring device is sometimes covered by the fluctuation of normal monitoring signal, which is difficult to identify by traditional operation and maintenance monitoring panel and abnormal alarm means. In order to solve the above problems, a prediction and trend analysis algorithm model of ARIMA is proposed to predict the change trend of driving current, realize the prediction of driving current in the next 8 hours, and analyze whether there is a growth trend of driving current by using the change rate. The practicability of the proposed method is verified by the analysis of the actual operation monitoring data of converter station, which can be applied to the trend analysis of driving current in DC measurement system.
Study on the Microstructure of Ni60 Coatings by Electromagnetic Field Assisted Laser Cladding
Authors: Liu Sitong , Ban Chunyan , Zhang Junwei , Li Hongwei
Published: April 2021

In this paper, Ni60 coatings were prepared on pure iron by electromagnetic compound field assisted laser cladding. The effect of the electromagnetic field on the microstructure of the coating was studied by changing the intensity of the electromagnetic field, the microstructure and phase composition of the coating were investigated by optical microscope (OM) and X-ray diffraction (XRD). The results showed that after applying the electromagnetic field, there were the flower-shaped structures and acicular constituents in the coating, and the grains at the top and middle of the coating were refined slightly. The number of flower-shaped structures and acicular constituents was the largest when the parameter of electromagnetic field was 1500A+0.2T, and a large area of fine grained region was found in the coating. In addition, the electromagnetic compound field could stir the molten pool and effectively reduce the porosity. The application of electromagnetic compound field did not change the phase composition of the coating, and the phase compositions of the coatings were still γ-Ni, CrB, Cr23C6 and Ni2B.
Cooperative Jamming of Multi UAVs to Netted Radar
Authors: Gao Zhi , Sun Hao , Li Fei , Guo Sai , Wang Jianming , Fang Lei , Zhao Chaohui
Published: April 2021

This paper analyzes the cooperative jamming problem of multi UAVs to netted radar, controls the given constraints, adopts the optimal control algorithm to analyze the movement law of UAVs in layers. Based on the single UAV track model, the cooperative jamming track model of multiple UAVs is established, and the optimal UAV track number and the number of false target tracks are calculated, The movement law of UAV track and false target track is analyzed. Firstly, according to the range deception principle of cooperative jamming of UAV to netted radar, the kinematics model of single UAV is established, and the motion parameters of false target point and UAV are obtained; on the basis of single UAV, the motion model of multiple UAVs Cooperative jamming netted radar is established, and the motion parameters of false target point and UAV are also determined. Since multiple UAVs need to meet the “homology test” of Netted Radars, it is necessary to select the optimal control algorithm to optimize the control of multiple UAVs to obtain the optimized UAV and false target track, so as to achieve the purpose of cooperative jamming. Then, according to the optimal trajectory of UAV, the change of speed is determined, and the number of UAVs is determined by selecting the number of time points of UAV moving in a straight line with uniform speed by optimizing the value of speed. In this paper, by layering the tracks of potential false targets, several reasonable tracks which are most likely to exist are selected, and then the tracks and motion laws of the other two UAVs are determined by the linear equation between these track points and the other two radars which determine the track points, flight altitude and flight speed.
Visual analysis of electrical signals
Authors: Fan Shengting
Published: April 2021

The sinusoidal spectrum of electrical signals is analyzed by using The Fourier series method and the Fast Fourier change method. Amplitude-frequency characteristic diagram and phase-frequency characteristic diagram are obtained respectively. The amplitude-frequency characteristic and the phase-frequency characteristic are superimposed in time domain and compared with the original signal. The analysis uses fast Fourier transform to analyze the minimum sampling frequency of electrical signals. The GUI module in MATLAB is used for programming, which makes the experimental parameters easy to modify. A more general conclusion can be drawn. Through experiments, we find that when the sampling frequency is more than twice the cut-off frequency of the original periodic signal, the fast Fourier transform method can better restore the original signal. When the sampling frequency is small, the signal will be seriously distorted. The amplitude-frequency and phase-frequency characteristics obtained by Fourier series can better restore the original signal when the harmonic frequency is large, but it is different from the original signal to some extent.