bluuebunny/crossref_metadata_2025 huggingface dataset:
A Learning model of STEM Education on cloud computing technology, to promote learning and innovation skills for students practicing teachers
Authors: Kerdthaworn Pornthip , Chaichomchuen Suthida
Published: April 2021

The purpose of this research was to: 1) analyze and synthesize STEM Education learning and innovation skills model on cloud computing technology to promote learning and innovation skills for students practicing teachers. 2) To learning and innovation skills Education teaching model, study on cloud computing technology to promote learning skills and innovation for students practicing teachers. 3) Evaluate the developed learning model by 6 experts in STEM education on cloud computing technology, using specific selection. With a sample group of experts in techniques and teaching methods Information and communication technology, 6 persons, using a specific selection The tools used in the research were 1) A learning model of STEM Education on cloud computing technology to promote learning and innovation skills for students practicing teachers 2) Assessment form for opinions about conceptual framework and 3) Suitability assessment form Analyze data using arithmetic mean and standard deviation. The results of the research were as follows: 1) The learning model consisted of 1.1) STEM supervision process 1.2) Learning and Innovation Skills 1.3) Users of the format comprised of teacher students and 1.4) Cloud processing technology 2) Opinions about the results of the analysis and synthesis of Full teaching and learning style, based on STEM Education on cloud computing technology to promote learning and innovation skills for students practicing teachers Overall, the level of opinion is at the highest level (x = 4.67, S.D. = 0.35) and 3) Appropriateness of Full teaching and learning style, based on STEM Education on cloud computing technology to promote learning and innovation skills for students practicing teachers. Consisting of the suitability of the design of the pattern and the appropriateness of applying the model to actual use the overall picture is at the highest level (x = 4.83, S.D. = 0.24)
Creative problem solving in climate change geography learning activity for primary school education via social media
Authors: Boonpo Piyanun
Published: April 2021

The paper aimed to clarify the developing instructional framework for creative problem solving (CPS) in climate change geography learning activity for primary school education via social media. The social media will be provided to engage students’ creative problem solving to identify and anticipate climate change geographical differentiation in potential impacts and vulnerability. The CPS climate change geography via social media was provided regarding on the five steps framework. This included 1) fact finding, 2) problem finding, 3) idea finding, 4) solution finding, and 5) acceptance finding. These CPS tasks for primary school students would enhance students to develop idea finding explicitly embedded and scaffolded fact finding, problem finding, idea finding, solution finding, and acceptance finding. The paper will discussed learning activities regarding on the 5 steps of CPS framework, strength point of the CPS climate change geography learning, and teachers’ role to facilitate students for the CPS.
ICT competencies for sustainability science teaching in 21st century
Authors: Teemueangsa Sanit , Hoxsuwan Suttipong , Jedaman Pornchai , Wangsaard Kollawach
Published: April 2021

ICT competencies for sustainability science teaching in 21st century needs appropriate ICT competencies in order for instructional to effectiveness. The data in this study came from documentary analysis include brainstorming and interview among the science teachers of primary and secondary education service areas under the basic education commission office. ICT competencies for demonstrating knowledge and skills using technology, training the learners use technology by themselves, creating to interactive and discovery learning, technology access of connects and communicates, use ICT skills in developing and presenting of informations, designing in effective learning to experiences and creating to rich learning environments, and using ICT as didactical tool to implements the collaborative learning.
Construct validity of attitude toward STEM self-inventory
Authors: Srikoon S , Khamput C
Published: April 2021

Attitude toward STEM influences on learning outcomes. The research purpose was to validate of attitude towars STEM. Sample are 393 students (Grade 7-Grade 12) for validating the Attitude toward STEM Self-Inventory (ASTEM). Totally 21 ASTEM items consist of 6 items of Mathematics Attitude, 6 items of Sciences Attitude, 6 items of Engineer/Technology Attitude, and 6 items of 21st Century Skill Attitude. Second-order confirmatory factor analysis was used to confirm the construct validity. The results confirmed that the construct validity of these test an excellent fit. The results show that: the fitness index of validating the ASTEM were as follow: x2 statistic is 254.650 (degrees of freedom = 220, p = 0.054), and the x2/df ratio having a value of 1.158 indicates a good fit. The comparative fit index (CFI) is 0.988, and Tucker-Lewis coefficient (TLI) is 0.984, Root mean square error approximation (RMSEA) is 0.020, Standardized Root Mean Residual (SRMR) is 0.045.
Status quo and needs of STEM Education curriculum to enhance creative problem solving competency
Authors: Thingwiangthong Pranee , Termtachatipongsa Phairoth , Yuenyong Chokchai
Published: April 2021

This research aimed to study of status quo and needs for developing STEM education curriculum to enhance creative problem solving competency. Methodology includes in-depth interviews and focus group. Target group were 42 stakeholders, including of school principals, science, mathematics, technology teachers, leader teachers of STEM education and students, in 7 schools within Khon Kaen STEM education network. Research instruments are fieldnotes. Data were analyzed by content analysis. Research result was summarized by analytic description. Research results found that 1) teachers organized STEM instruction through STEM club, additional subject, moderate class–more knowledge activities. Moreover, teachers blended the idea of STEM into teaching in mathematics, science and technology. For STEM instruction problems, some activities do not conform to their school context. Additionally, time for organizing STEM activities and budget for producing learning materials are not enough. 2) Teachers need STEM education curriculum that appropriate for their school context and conform to students’ daily life. It should be designed by collaboration of teachers. It should be able to respond to all students with different abilities. STEM instruction should be focus on students to plan, design, implement, practice, summarize for solving problem and to classify new knowledge associating with science, technology, engineering, or mathematics.
Development of differentiated activities in teaching science: educators’ evaluation and self-reflection on differentiation and flexible learning
Authors: Variacion D A , Salic-Hairulla M , Bagaloyos J
Published: April 2021

This study determines the evaluation of educators to the developed differentiated activities in the learning module. Developed differentiated activities for grade-seven science class were assessed and evaluated by educators. Three academic administrators, two of which are science teachers, six junior high school science teachers of La Salle Academy and four in-service Department of Education teachers participated in this research study. Through mixed-method research design, where quantitative designs, weighted-mean, independent-sample t-test and standard deviation analysis, the comparison of evaluators’ ratings in a DI and Non-DI Learning Module were determined. Findings showed that, the developed Learning Module with Differentiated activities received very good to excellent ratings from the evaluators. Based from their ratings, teachers significantly gave higher ratings to the Developed Differentiated Learning Module compared to Non-DI Learning Module. Furthermore, results in their self-reflection indicated that educators see the Developed DI – Learning Module as opportunity and avenue of students to develop the values of patience, teamwork and safety. Thus, these results were discussed in relation to making teachers equipped in using differentiated and flexible learning teaching strategies and practices that may contribute to closing the achievement gap among Filipino students.
Period Change and Third Body Analysis of a Binary Star V523 Cassiopeiae
Authors: Maithong Wiraporn
Published: April 2021

V523 Cassiopeiae (V523 Cas) is a W UMa type of the eclipsing binary system which its orbital period is 0.23369 days. This study using a 0.5-meter telescope with CCD photometric system in V and R filters was conducted at the Regional Observatory for the Public, Chachoengsao, Thailand during 20 – 21 December 2018, UT. The obtained data were calculated using photometry method to construct the light curve of each wavelength bands and to determine the time of minimum. Consequently this study obtained the time of minimum of V523 Cas that HJD2458472.996 and HJD2458473.111, respectively. These values were used to compute the O-C curve and period change. The results show that the period of the V523 Cas is increasing which the rate of 5.59 × 10−3 second/year. Furthermore, the V523 Cas might be the third body in its system which far from the center of mass about 6.04 AU the orbital period is 91.3 years.
Development and validation of contextualized lesson in mathematics
Authors: Buan Amelia T. , Ali Anna Zohayma Mustapha , Gomez Rizalina
Published: April 2021

The poor academic performance of students in the Marawi City Division on Measurement was evident in the conducted summative tests. This perennial problem needs to be addressed by the school district. One way that can help boost students’ conceptual understanding is the use of contextualized lessons. This approach enables the students to engage in the procedural process that would improve their problem-solving ability. The purpose of this study was to develop contextualized problem in Measurement in coming up with a Contextualized Lesson Plan in mathematics that would improve the academic

performance of the Grade students in their achievement test. This study used the quasi-experimental design with qualitative support. There were significant improvements to the students which belonged to the Experimental Group than those students in the Control Group. Moreover, students perceived that contextualized lessons as relevant and comprehensive. Since students displayed positive responses on the activities and improved their performance in the achievement test, the researcher, therefore, recommended teachers may adopt the use of contextualized problem in teaching Measurements in the mathematics subject.
A disposable and cost-effective electrochemical DNA sensor using nanocomposite modified screen-printed gold electrode
Authors: Thipmanee Orawan
Published: April 2021

This research involved the preparation of an electrochemical biosensor using a disposable screen-printed gold electrode (SPGE) for the DNA hybridization detection. An electrochemical DNA biosensor was successfully fabricated based on DNA probe tagged with methylene blue (MB) as redox hybridization indicator, was immobilized on the nanocomposite modified electrode. The modified SPGE was characterized by using cyclic voltammetry (CV) and scanning electron microscopy (SEM) with energy dispersion x-ray spectroscopy (EDS). The current signal of target DNA hybridization was monitored using differential pulse voltammetry (DPV). These DNA biosensor showed a good current response with the complementary target DNA concentration range from 1.0x10-11to 1.0x10-7M. This fabricated genosensor could also be regenerated easily and can be reused 36 times for hybridization studied.
Solid Waste Management in Banthreampunya School. La-ae subdistrict, Yala Province, Thailand.
Authors: Masawat Jariyaporn , Rangpan Vichit , Thongmak Narumol , Kaewmanee Jutamas
Published: April 2021

The purpose of this study was to investigate solid waste and its contents in Banthreampunya School, La-ae subdistrict, Yaha District, Yala Province. The result was used in planning and managing solid waste disposal system within Banthreampunya school. The researcher employed literature review, local survey, observation, as well as students’ participation, and school staff which include teachers for data collection and collaborated planning for the best solid waste management system that should be implemented within the school. The result of the study showed the contents of school solid waste consist of 4 major types of waste i.e. recyclable waste, organic waste, general solid waste, and hazardous waste in the percentage proportion of 48.93, 32.21, 14.50, and 4.36 respectively. The consensus agreement between participating parties has been reached to solely manage the recyclable waste by means of waste bank to reduce and add value to the waste.
Effect of acid treatment substrate for supercapacitor electrode based on multi-walled carbon nanotubes
Authors: Dulyaseree Paweena , Wongwiriyapan Winadda
Published: April 2021

Effect of acid treatment substrate for supercapacitor based on multi-walled carbon nanotubes (MWNTs) electrode was investigated. The electrode was used as stainless steel type 304 (SS304) and was with hydrochloric acid (HCl) acid-treated before use. Firstly, SS304 substrates were soaked in 37% HCl for designated time. Acid treatment times were varied at 0, 5, 10 and 15 min. Their surface morphology, elemental components and hydrophilicity property of the acid-treated SS304 were analyzed. The 10-min-treated SS304 show the lowest contact angles, indicating the best hydrophilicity property. Electrode material was prepared by composites of MWNTs, polyvinylidene fluoride (PVDF) and n-methyl-2-pyrrolidone (NMP) with an area of 5x5 mm2. Their cyclic voltammetry (CV), galvanostatic charge/discharge (CD) and electrochemical impedance spectroscopy (EIS) were characterized. The 10-min-treated SS304 exhibits the best performance with a specific capacitance (SC) of 261.04 Fg−1. The improvement of the SC of the acid-treated substrate was contributed to the adhesion improvement between a current collector and an electrode material, and the hydrophilicity improvement, resulting in a large amount of electrolyte ions accessing into the electrode materials and subsequently enhancement of their capacitive characteristics.
Foraging plant and palynological analysis of stingless bee pot-pollen in Pattani, Thailand
Authors: Chelong Isma-ae
Published: April 2021

This is the first foraging plant and palynological study using pollen stored by Heterotrigona itama (Apidae: Meliponini) in the Saiburi, Pattani, Thailand. The samples were directly collected from the pollen pots of H. itama species in apiaries located in Saiburi district. The samples were dried, weighed, diluted in warm water and ethanol, centrifuged and then processed using the acetolysis method. After mounting the pollen samples on the glass slides, we identified and counted at least 500 pollen grains per sample. The results show that the main pollen combinations in the pollen pots of H. itama include pollen from Wedelia, Acacia, Cocos and Elaeis. Most pollen types came from the families Mimosasae, Graminae and Asteraceae family
Estimation of convective heat transfer coefficient in agricultural products under solar drying conditions
Authors: Saniso Eleeyah , Sukeaw Adulsman , Seni Lutfee , Wamae Warisa , Hayibaka Muhammadkhoiri , Rojanasuwan Sunit
Published: April 2021

This research estimated convective heat transfer coefficients of agricultural products (banana, taro and chili) under solar (open sun) drying conditions using the Nu = h
c(X/K
v) = C(Ra)
n
equation. Values of constants C and n were obtained by linear regression analysis. Results showed that natural convective heat transfer coefficients of agricultural products were in the range 0.720-3.559 W/m2·oC. The C value of agricultural products was 1.0000-1.0011, while n was in the range 0.071-0.274, Pr = 0.697-0.705 and 2.931×105-1.803×108 < Gr < 6.139×108-2.230×109.
Physical-Chemical Properties Relationship of Pattani River and Implication for Water Quality Monitoring Study and Academic Service
Authors: Maprasit S , Pradabphetrat P , Madmanang R , Sathawong S , Boonkaew R , Suksaroj C
Published: April 2021

STEM learning is methodology toward providing students with cohesive and conducive learning environments that expand their knowledge in fields relating to technology, engineering, mathematics, and science. The environment learning and management is large scale impacted by the people who do the actual influencing, teaching and managing. Pattani River is considered as the important river of the southern region. Which has a length of 210 kilometers, is an important river for environment studying and developing area including academic place, industrial-agricultural area and domestic settlements across Yala, Pattani and Narathiwat province. The river consumption which should be studied and monitored to assess and prevent deterioration Especially the part of the river that passes through urban communities like Yala and Pattani Municipality. Therefore, this research aims to study the relationship between physical water quality and chemical water quality of water in the Pattani River. Classified by water sampling stations Land use and seasons The research was conducted using a single sample water collection method on the waterfront and in the middle of the Pattani River that flows through the Yala province, with 11 sampling stations. Used to analyze pH, temperature, transparency, electrical conductivity, suspended sediment and dissolved oxygen once a month from January-June 2019 and the remaining data from the Office of Natural Resources and Environment, Region 16. The results showed that the water quality varies with the season (p-value < 0.05) but does not vary with water sampling stations and land use. In the dry season, Pattani River has higher water quality than the rainy season. For areas that do not have land use, water quality is slightly better than agricultural and community areas. Chemical water quality such as pH and dissolved oxygen are related to physical water quality changes such as transparency, electrical conductivity and temperature (p-value < 0.05). Which can be used as a guideline to prevent degradation of water quality and can be developed into indicators that can be applied to communities Causing the Tambon Administrative Organization and the community to be ready to be a leader in monitoring water quality.
Effect of La-Ce Mixed Rare Earth on High Temperature Deformation Behavior of 685 Armor Steel and Its Mathematical Model
Authors: Zhang Mingyi , Gao Ping , Luo Guoping , Geng Wenyuan , Jia Xiaobin , Cao Yong
Published: April 2021

A thermal simulation test machine was used to conduct high-temperature compression tests on two sets of 685 test steels with and without rare earths. Through linear fitting analysis and microstructure observation, the effect of rare earths on the high-temperature deformation behavior of 685 armored steel was studied. The results show that when the deformation temperature is 1000°C, La-Ce mixed rare earth can increase the deformation resistance of steel, and the influence varies with the amount of compression deformation, while at 1100°C, the rare earth has no obvious influence on the deformation resistance of steel. After adding rare earth, the recrystallization activation energy of steel is increased by 6.78%. Mixed rare earth (La-Ce) has an inhibitory effect on the recrystallization of steel. Using Origin8.0 software for regression analysis, a mathematical model of armored steel containing rare earths is established. The model has good curve fitting characteristics, and the calculated values are basically in agreement with the experimental values.
Effects of Heat-Treatment on Microstructures and Mechanical Properties of Hot Deformed Ti-6Al-4V Alloy
Authors: Wang Qiang , Zhang Zhaohui , Zhang Shunzhong , He Jiangye
Published: April 2021

In this paper, Ti-6Al-4V alloy were successfully fabricated using a Spark Plasma Sintering (SPS), thermal deformation and heat treatment process. SPS sintering is divided into two steps: The first step is low-temperature molding at 600°C and 300 MPa, and the second step is thermal deformation at 800°C, with a deformation of 70%. The effects of solution treatment and aging process at temperatures above and below the β transformation point on the microstructure and mechanical properties of Ti-6Al-4V are investigated. The study found that the mechanical properties were better after treatment (900°C, 30 min+ water quenching +550°C, 4 h).
Non-Destructive X-ray Evaluation and Gap Measurement of Ceramic Armor Plate
Authors: Li Guofei , Wang Zhiwei , Yang Lin , Wang Xiaodan , Wang Lin , Xu Hai , Miao Cheng , Wu Yuchao , Guo Yiyan
Published: April 2021

Ceramic armors are usually made of a close-fitting periodic array of ceramic tiles, and have gaps between the tiles. The ballistic performance of the ceramic armor is highly affected by the gap width and it is important to find a way to inspect and evaluate it with no destruction. So the gaps of two ceramic armor plates, which were respectively made through hot-press vulcanization machine and autoclave system, were inspected and measured by a non-destructive X-ray evaluation method. But because of the magnification effect of the X-ray method, the measured gap width was not real. So that, it is critical to find the relation between the actual gap width with the measured. Though analysis of the magnification effect of X-ray inspection, we proposed a formula between the two, and calculated the actual gap width of the two different armor plates. It could be concluded that the autoclave method was better, with mean gap width was only 34% of that hot-press vulcanization machine made.
Energy Absorption Characteristic of Thin Monolithic Q235 Steel Plates Under Oblique Penetrating of Ogive-Nosed Projectiles
Authors: Chen Shengpeng , Pang Baojun , Cao Wuxiong , Chi Runqiang
Published: April 2021

In this paper, the energy absorption characteristics of single thin Q235 plates impacted by ogival-nosed projectile obliquity were modeled analytically. We offer an empirical formula involved quasi work, petal dynamic power and petal bending to describe the energy consumption of hardened projectile. The energy dissipation at ballistic limit velocity for projectile was obtained based on the empirical formula. Comparing with the energy value at ballistic limit velocity that fitted by simulation results, the analytic value agrees well with the numerical value that validated by experimental. The results show that the analytical formula can determine the energy absorbed by the thin monolithic Q235 target perforating by ogive-nosed projectile at oblique impact.
Shear Thicking and Impact Resistance Properties of STG in Flexible Protection Application
Authors: Zong Hao , Liu Zhipeng , Wei Rubin , Dong Bin , Yang Xingjuan , Zhai Wen
Published: April 2021

The rheological properties of shear thickening gel(STG) and its application as protective composite were studied in the paper. Upon applying a shear stress with excitation frequency from 1 Hz to 100 Hz, the storage modulus (G’) of the STG increases from 101 Pa to 105 Pa, demonstrating an excellent shear thickening effect. The reduction of temperature increases the G’min of STG, but when the temperature reaches at 50°C, the G’ curve shows a moderate slope and a gradual transition to the constant plateau value. By introducing STG into polyurethane foam and kevlar fiber with dip and dry method, successfully fabricate a nove safeguarding polymer composite. The protective performance of composite protective materials was studied by static compression experiment and drop hammer impact experiment. The addition of STG increases the impact resistance and puncture resistance of PU and kevlar by at least two times. The materials shows excellent shear stiffening effect, creep resisting and impact resistant propertie.
Influence of Modified Energetic Materials on the Protective Effect of Reactive Armor
Authors: Hao Fei , You Yang , Chen Jianshen , Zhang Jianren , Feng Xiongbo , Xu Peng , Huang He , Liu Wei , Li Mei , Guo Zhen , Zhang Wei , Li Lei
Published: April 2021

In order to improve the protective performance of reactive armor, the development course and present situation of reactive armor at home and abroad were described in detail, and the influencing factors of energetic materials on the protective performance of reactive armor were analyzed carefully. Finally, the protective performance of reactive armor of common type energy energetic and high energy energetic material was compared by numerical simulation and experimental verification. The results show that the protective ability of reactive armor can be improved by more than 10% compared with the common energetic materials reactive armor.
Study on the Interference of Multi-point Shaped Charge Structure on Jet
Authors: Liu Bowen , Zhou Tong
Published: April 2021

in order to improve the defense ability of reactive armor against shaped charge jet, a multi-point shaped charge structure is designed in the first layer of traditional explosive reaction armor, and the active passive combination method is used to interfere with the jet. The specific action process is as follows: after obtaining the signal of series warhead charge impacting explosive reactive armor. Take the initiative to detonate the shaped charge. Multiple damage elements are formed to interfere with the shaped charge jet actively. Based on LS-DYNA, the numerical simulation of multi-point shaped charge structure is carried out, and the charge structure and angle are optimized. The results show that the damage elements in different directions can be focused along the axial direction of the incoming jet by adjusting the charge structure. Changing the focal length of the converging jet can cause interference or fracture at different positions of the jet. The research results of this paper can provide reference for the design of active passive reactive armor.
Effects of Charge Type and Structure Parameters on Armor Protection Performance
Authors: Li Hao , Yin Jianping , Han Yangyang , Bi Guangjian , Qi Jiawen , Cui Hailin
Published: April 2021

In order to improve the reaction armor protection, this paper armours of interlayer charge and the thickness of the steel plate and charging ratio analysis, based on the reaction between armor and jet interaction, established the reactive armor and shaped charge of finite element model, using AUTODYN software, adopt the method of fluid-structure interaction for numerical simulation research. The results show that compared with other explosives, CL-20 has an ideal interference effect on jet flow. In the designed structure, the reactive armor with a steel plate thickness of 4 mm and a charge thickness of 8mm achieves the best protective performance.
Mechanical Performance of Spacecraft Protection Structure Under Hypervelocity
Authors: Bi Guangjian , Yin Jianping , Wang Zhijun , Han Yangyang , Jia Zijian
Published: April 2021

In order to improve the ability of the spacecraft protection system to resisted hypervelocity orbit debris, a composite double-layer honeycomb sandwich structure was proposed in the article. Four sets of models were established, through the method of controlling variables, and the SPH algorithm of the LS-DYNA finite element software was used to analysis the composite honeycomb sandwich structure. The diameter of the aluminum ball was 7mm and the velocity was 5818m/s. The results show that the residual velocity of debris cloud decreases with the increase of the cell diameter of the front-stage honeycomb. and the residual velocity of debris cloud increases with the decreases of the cell diameter of the back-stage honeycomb structure. The energy absorption effect of the composite structure was much higher than that of the traditional honeycomb structure, the remaining speed was reduced by about 64%, and the total energy absorption was increased by 77.6%.
Analysis on the Development of Active Protection System for Tanks and Armored Vehicles
Authors: Yang Likun , Xu Jiagang
Published: April 2021

Tanks and armored vehicles are facing increasingly diverse threats on the battlefield. Active Protection System (APS) can apparently enhance the protection capability of tanks without reducing mobility. The principle of active protection technology is introduced, and particularly the performance of radar detection subsystem and intercepting ammunition subsystem are analyzed. Moreover, the application status of APS is elaborated and the current level and main deficiency are dissected. Furthermore, the probable development trends of APS are listed.
Research Progress of Armor Protection Materials
Authors: Bao Yuguang , Gao Xiaoju , Wu Yuchao , Sun Mengyong , Li Guobin
Published: April 2021

With higher requirements of ballistic performance put forward by the new generation of armored vehicles, the development of new armored materials at home and abroad has made great progress. In this paper, the development status of composite ballistic armor used in armored vehicles at home and abroad is reviewed, the future development demand of composite ballistic armor used in armored vehicles is summarized, and the application prospect of new materials such as gradient functional materials, micro-laminated materials, graphene modified ceramics in armored vehicles is prospected. In order to meet the independent development needs of armored vehicles in China, it is urgent to develop new advanced lightweight protective materials with excellent performance. Only by developing new armor materials can we improve the survivability of our armored vehicles, meet the operational requirements of our weapons and equipment, and realize the synchronous development with advanced armor protection technology in the world.
Effect of Laser Beam Focusing Adjustment on the Processing Quality of Aluminum Nitride Ceramic Micro-Holes
Authors: Yang Chunyan , Hao Yun , Li Yangping , Wang Bozhe , Yuan Hai , Li Liuhui
Published: April 2021

The Gaussian laser beam was used to drill micro-holes with a diameter of 500μm on a 0.15mm thick aluminum nitride (AlN) ceramic. The geometry, processing quality, and surface fusion of the micro-holes were studied. The fusion recast layer at the edge of the hole is thick, the inner wall of the hole has a lot of slag, and the side wall of the laser entrance area is seriously inclined. Through spatial reshaping and focusing of Gaussian light, Bessel light with higher energy density, greater depth of focus, and smaller beam spot was achieved and used to perforate AlN ceramics. The fusion recast layer at the periphery and inner wall of the hole are both very thin, and the taper of the hole is very small. These results show that the focusing adjustment of the laser beam has a significant impact on the processing quality of AlN ceramic micro-holes.
Design of an Adaptive Lock-in Amplifier for the Terahertz System
Authors: Zhang Zhaohui , Liu Yongli , Zhu Xinyong
Published: April 2021

In order to extract the weak terahertz signal in the terahertz time-domain spectroscopy (THz-TDS), and to solve the problem of single amplification of the existing lock-in amplifier or manual adjustment of the amplification, a lock-in amplifier with self-adaptive adjustment function for phase and amplification is designed. Compared with the traditional lock-in amplifier, it reduces the use of electronic components such as phase shifters, modulators and summators, and reduces the development cost of the circuit. The phase shifting module and the amplification factor of the amplifying circuit are controlled by the MCU control unit and the magnitude of the received feedback signal respectively. The dynamic range of the terahertz time-domain spectroscopy system using phase and amplification adaptive lock-in amplifiers indoors can reach 70dB. The test results show that the designed lock-in amplifier can effectively improve the dynamic range of the terahertz system, and is more convenient for real-life applications.
Influence Factors of Gravitational Acceleration near the Earth
Authors: Shi Xuefeng , Wang Xingsheng , Zhang Ling , Guo Kaimin
Published: April 2021

Objects on the earth are subject to gravity due to universal gravitation. This paper systematically studies the influence factors, including latitude, altitude, depth inside the earth, surrounding stars, on gravitational acceleration of object near the earth. The results show that latitude has a relatively large impact on gravitational acceleration; depth and altitude have the greatest impact on gravitational acceleration. The orbit and the position of the object (dayside or nightside of the earth) have little effect on the gravitational acceleration of the object. Our work can offer reference for accurate calculation of gravity acceleration.
Tunnel Lighting Intelligent Control System Based on Ambient Light Ratio
Authors: Liu Suying , Jiao Chenfei , Zhu Chong
Published: April 2021

Based on the research problems of modern tunnel lighting control technology, a tunnel lighting intelligent control system based on ambient luminosity ratio is designed, which is characterized by “car close lights bright, car passing lights dark”, intelligent analysis of system failures, etc. The core technology is LED Tunnel light group brightness automatic adjustment, python data analysis, etc. The design of the core control unit of the system is based on the STC89C52 chip, which uses the numpy module in python to matrix the data in the database through the information collected by the sensor (the light intensity inside and outside the tunnel, the traffic condition of the vehicle in the tunnel, and the working condition of the tunnel lighting equipment, etc.) Level storage and use principal component analysis and other algorithms to perform a large number of calculations and processing on the obtained data. The controller generates a corresponding PWM signal to control the brightness of the LED tunnel light group to solve the problem of excessive lighting or insufficient brightness; through other controls The components exchange information, and the downstream controller performs calculation and processing according to the control instructions sent by the previous stage and the real-time signals detected by the sensors to realize the selective brightness and automatic brightness adjustment of the tunnel section lighting, and finally achieve intelligent control, energy saving and emission reduction the goal of. In addition, we use the seaborn library and matplotlib library in python to visually display the obtained tunnel lighting equipment working condition data, and send the results to the relevant road management department. This will play an important role in greatly improving the efficiency of activities such as equipment maintenance, collecting equipment work information, and optimizing the work structure of road management. To a certain extent, it is conducive to the implementation of specific work of relevant departments.
Band Structure Engineering of Black Phosphorus/Graphene/MoS2 van der Waals Heterojunctions for Photovoltaic and Optoelectronic Device Application
Authors: Zhu Wenhuan , Kong Lingwei , Long Wei , Shi Xianglei , Zhou Dayong , Sun Lijie , Zhou Lihua , Yang Guiting , Liu Xiaodong , Liu Hai , Bo Maolin , Hou Xiaoqiang
Published: April 2021

In this paper, we study the band structure engineering of black phosphorus/graphene/MoS2 (BP/graphene/MoS2) van der Waals heterojunctions based on ab initio simulations. The density of state and charge density of BP/MoS2, bilayer-BP/MoS2, bilayer-BP/graphene/MoS2 and graphene/bilayer-BP/MoS2 heterojunctions are also investigated. It is found that the bandgaps of these four heterojunctions are smaller than the case of single layer BP or MoS2. When graphene is inserted into or stacked upon BP and MoS2 layers, the heterojunction can obtain a minimum bandgap and a higher density of state distribution. In the differential charge density diagram, electrons over the carbon, sulfur and phosphorus atoms are lost from those corresponding parts. These investigations based on the band structure engineering of 2D van der Waals heterojunctions can provide an effective guidance to manufacture the future nanoscale high performance photovoltaic and optoelectronic devices.
Research Progress on Calendula officinalis Pb/Cd Compound Pollution
Authors: Chang Min
Published: April 2021

This paper analyzes the existing treatment methods of heavy metal Pb and Cd pollution, and obtains the advantages and researchable value of phytoremediation technology. The research value of the short-lived flower crop Calendula officinalis in the adsorption of heavy metal Pb and Cd compound pollution. The research value of the short-lived flower crop Calendula officinalis in the adsorption of heavy metal Pb and Cd compound pollution. The research value of the short-lived flower crop Calendula officinalis in the adsorption of heavy metal Pb and Cd compound pollution. short term crop calendula flowers in the adsorption of heavy metals Pb, Cd research value complex pollution. short term crop calendula flowers in the adsorption of heavy metals Pb, Cd research value complex pollution
Research on Multi-Source Heterogeneous Data Fusion Technology of New Energy Vehicles Under the New Four Modernizations
Authors: Zhang Fan , Yang Jing , Sun Chuan , Guo Xin , Wan Tiantian
Published: April 2021

In order to better adapt to the development trend of the city, new energy vehicles are widely used to fit the development concept of green transportation. As the focus of smart city development, big data is indispensable for its application in new energy vehicle guarantees, especially in maintenance and machinery guarantees. In the operation and maintenance of new energy vehicles, the application of multi-source heterogeneous data technology is extremely important. Based on this research background, the paper introduces and constructs the new energy vehicle fault feature vector of the new energy vehicle, gives a multi-source time domain frequency domain data fusion new energy vehicle fault diagnosis method, and uses the neural network to give the basic probability distribution. The evidence theory fuses the signals of each sensor to get the diagnosis result.
The key Research on Improving the Anti-jamming Performance of POF Displacement Sensor
Authors: Zhang Sen , Xue Huili
Published: April 2021

In weak signal detection, interference and noise have become important factors that limit and affect measurement sensitivity, accuracy, and repeatability. In order to comprehensively improve the anti-interference performance of the POF displacement sensor, it is necessary to reduce and eliminate the harmfulness of interference and noise. However, in the actual application environment, the optical signal of the measured information is often submerged in interference and noise. In order to effectively detect the weak signal under test and improve the anti-jamming performance of the entire sensor, the techniques often used include frequency domain narrowband technology, time domain averaging processing technology, discrete counting statistics technology, computer processing technology, light modulation technology, Amplification technology, correlation detection and low-pass filtering and other key technologies are the key to improving the anti-interference performance of the POF displacement sensor.
Integrated Evaluation Criteria of Economic Benefit and Energy Value Efficiency of Micro Grid
Authors: Wang Xudong , Qi Yan , Li Jinze , Nie Jingyu , Wu Binyang , Su Wanhua
Published: April 2021

An evaluation criterion of micro grid is proposed from the perspective of economy, energy conservation and emission reduction. The heterogeneous energy such as cold, heat and electricity based on the micro grid taking combined cooling heating and power as the core was evaluated based on the energy value through the cascade utilization of energy, and the micro-grid optimization model including the micro-turbine, waste heat boiler, lithium bromide absorption chiller, fan and photovoltaic was established. As compared with the model of cost optimization only, its integrated optimization index increased by 11.547% and the efficiency of exergy increased by 14.651%.
Design and Synthesis of CaMoO4 Microspheres and Their Optical Properties
Authors: Shen Wanyi
Published: April 2021

CaMoO4 microspheres materials were prepared by hydrothermal synthesis method using CaCl2 or Ca(NO3)2 and ammonium molybdate as reaction raw material at 170°C. XRD analysis shows that the product indexed to tetragonal phase of CaMoO4. FESEM images exhibit that the product is spherical and the diameter of the microsphere is about 5 μm. PL spectrum indicates that the photoluminescence emissions intensity of CaMoO4 depended on the morphologies and sizes of the products.
Preliminary screening of Salmonella in oral drugs by visual LAMP technology
Authors: Huang Xuchun , Zeng Chuanping , Niu Ling , Li Xiaotian , Chen Linzhu , Ma Guangqiang
Published: April 2021

Objective According to the Chinese Pharmacopoeia, Salmonella should not be detected in oral drugs. In this experiment, LAMP technology was used to detect Salmonella quickly, and the detection results were visible to the naked eye with calcein-Mn2+ dye, so as to provide pharmaceutical companies with the initial screening of drugs containing Salmonella. Methods Four primers (FIP, BiP, F3, B3) were designed to detect Salmonella by loop mediated isothermal amplification using inv A gene of Salmonella, and then the loop mediated isothermal amplification detection method was established. To verify the specificity of the method, LAMP detection was carried out on 10 kinds of laboratory preserved strains. The sensitivity of the method was obtained by detecting 10 times gradient dilution of Salmonella bacteria solution. Finally, the LAMP system of Salmonella was used to detect the oral drugs sold on the market and not tested by the Drug Administration, and the sensitivity of the system in the drug was determined. Based on these methods, Calcein-Mn2+ dye was added to test the availability of the dye. Results After optimization, the specificity of the system was good. For 10 different strains of LAMP detection, only Salmonella appeared trapezoidal band, and other strains did not detect the band; Through the experimental verification, the sensitivity of the system was 3.2 × 101 CFU/mL; The system was used for the oral drugs sold in the market and not passed the inspection of the drug administration The results of LAMP detection showed that no Salmonella was detected. However, the results of LAMP detection showed that there were trapezoidal bands in the test results. The sensitivity of the system in the detection of Salmonella in oral drugs could reach 3.8 × 101 CFU/mL. Adding calcein-Mn2+ dye into the system, the presence or absence of Salmonella can be distinguished by naked eye observation, and the detection limit is about 102 CFU/mL. Conclusion The visual LAMP detection system for Salmonella can be used for the preliminary screening of oral drugs containing Salmonella.
Adaptive Asymmetric Frequency Hopping Communication Scheme Based on Spectrum Hole Detection
Authors: Sun Bingcheng , Li JinFeng , Cui Hongfeng
Published: April 2021

With the development of frequency hopping communication, the problem of anti-jamming becomes more and more prominent, According to the techniques of spectrum estimation and spectrum holes detection in cognitive radio, a adaptive asymmetric frequency hopping communication scheme is proposed. More frequency points can be found between transmitting terminal and receiving end according to the result of spectrum hole detection, the transmitting frequency tables and receiving frequency tables can be dynamically altered in real time, the anti-intercepting and anti-jamming capability of communication can be improved, and the efficiency of the spectrum usage can be promoted. This thesis is helpful to anti-jamming research, analysis and design of AFH communication systems.
Controllable optical resonances and unidirectional scattering by core-shell nanoparticles
Authors: Dong Yiwei , Yang Yuanqing
Published: April 2021

Nanoparticles supporting a distinct series of Mie resonances have enabled a new class of nanoantennas and provide efficient ways to manipulate light at the nanoscale. The ability to flexibly tune the optical resonances and scattering directionality are particularly essential for various applications ranging from biosensing to nanolasers. In this paper, we investigate the core-shell nanoparticles that support both electric and magnetic Mie resonances and for the first time systematically reveal the mode evolution from a pure high-index dielectric nanosphere to its plasmonic counterpart. Abrupt mode transition and hybridization of Mie resonances are found in Ag-dielectric core-shell spheres when core-shell ratio increases from 0.4 to 0.5. Furthermore, by engineering the electric and magnetic resonances, we demonstrate the unidirectional forward and backward scattering in such a system and reveal its tunability via geometric tuning.
Effect Analysis of Laser Shock Peening on Nickel-based Alloys by Laser Solid Forming
Authors: Ma Wanli , Jia Changzhi
Published: April 2021

Laser solid forming has the advantages of rapid and complex shapes, but the stress caused by high temperature gradient changes during the forming process can easily lead to the deformation of parts and insufficient mechanical properties. This article focuses on laser solid forming GH4169 superalloy for laser shock peening. The influence of process parameters on surface morphology and toughness were analyzed. The mechanism of laser shock peening was analyzed. The results show: As the number of impacts increases, the depth gradually increases, and the increasing trend slows down. When the energy is small, the surface change cannot be observed. After 5J, as the energy increases, the depth of the pit increases. As the impact energy increases, the toughness of the material first increases and then decreases. The toughness of the material is the highest at 6J, reaching 65J/cm2. The action mechanism of laser shock peening has three main methods, one is fine-grain strengthening, the other is twinning and work hardening, and the third is stress strengthening.
Research on Comprehensive Evaluation Method of Power Grid Efficiency
Authors: Cheng Chao , Wang Haiyan , Wang Ziyi , Ren Zhichao , Lan Mengxin
Published: April 2021

Power Grid Efficiency directly affects the development level of the company and is an important embodiment of the company’s comprehensive strength and market competitiveness. Different from the previous single cause analysis, this paper uses the earned value method to evaluate the project progress objectively and systematically, and establishes the relevant evaluation index system, so as to have certain reference value for the company’s decision-making adjustment.
Design of flexible maintenance robot based on Gas Insulated Substation
Authors: Ma Yuhang
Published: April 2021

Gas Insulated Substation (GIS) is a metal enclosed switchgear with SF6 gas as insulating medium, also known as gas insulated substation. Because of its compact structure, high security, easy installation and other characteristics, GIS is widely used in the assembly of all kinds of equipment except the main body of transformer. Due to the unique fully enclosed structure of GIS and the complexity of its own gas chamber, manual maintenance is often adopted at present, which is not only difficult but also dangerous. Based on the author’s understanding of flexible robot, a method of intelligent maintenance of GIS cavity with flexible robot is proposed. The flexible robot has a long and narrow structure, and can move flexibly in complex environment. It can also carry sensors and operating equipment into the GIS cavity, and use intelligent control, image recognition, machine learning and other technologies to determine the type and location of GIS faults and deal with them. Through this method, the maintenance of GIS is completed.