A simple experiment shows an interesting phenomenon of an object system in apparently static state exhibiting overweight and weightlessness. Such a complicated object system includes container,water,and balloon,among which the weight of the floating body is unequal to the interplay force with water once the equilibrium state is broken. Because of change in the thermodynamic state of the balloon,the buoyancy force and hydraulic pressure also change with it,directly resulting in that the platform balance shows overweight and weightlessness. The floating body spontaneously changes its movement in upright direction from the non-equilibrium to equilibrium states accompanied by an increase in entropy. Based on it,the concept of macro-entropy change due to mechanical work done by gravity is proposed. Furthermore,the increases in the macro-entropy change mean the spontaneity of change in state,and the existence of difference between the self-weight of moving object and the interplay with water,by which we can judge the overweight and weightlessness. Meanwhile,we also give a demonstration on how to analyze the changes in mechanical state and forces for complicated object system.

Free fatty acids (FFAs) play a vital role in human physiological activities,and as tumor detection markers,FFAs have significant advantages in sensitivity and specificity. It is of great significance for accurate determination of FFAs in serum for scientific research and clinical diagnosis. This study developes a new detection method of rapid,highly selective and high-throughput analysis for FFAs in serum based on the advantages and limitations of matrix assisted laser desorption-mass spectrometer (MALDI-MS) and stimuli responsive molecularly imprinted membrane (Sr-MIM) technology. The technique provides a new idea for the trace analysis of small molecular compounds in complex samples by MALDI-MS. At the same time,it broadens application scope of large instruments,which is conducive to improving the sharing efficiency of advantageous resources. It has been deeply applied in college students’ innovation training programs to stimulate students’ academic interest and innovation potential,improve the quality of training top-notch innovative talents,and create a free and innovative scientific research ecological environment.

The oncolitic limestone of Chuanshan Formation is an important building material widely distributed in the middle and lower reaches of the Yangtze River and southeastern coastal provinces. Based on the theory of fracture mechanics,this paper discusses the process of micro-crack propagation and macro-fracture of nuclear limestone under tensile stress by polarized light microscope and scanning electron microscope. Studies have shown that there are microcracks at the interface of oncolite particles,secondary pores,intergranular pores,etc.,and micro-crack propagation needs to consume energy. When the crack expands near the oncoids,there are two different paths to bypass the oncoids or pass through the oncoids,which mainly depends on the structural factors such as the type of oncoids,structural density,and particle size.

Reservoir pore structure evaluation is of great significance for the oil and gas resources exploration and development as well as carbon dioxide geological storage. It is an effective means to predict capillary pressure curves based on the transverse relaxation time (T2) spectra from nuclear magnetic resonance (NMR) logging for the reservoir pore structure evaluation. Aiming at the strong theoretical nature of the conversion model and the complexity of the principle,a simulation experiment for NMR logging T2 spectra-based reservoir pore structure evaluation is designed with MATLAB GUI. The interactive interface contains three modules,i.e.,capillary pressure curve preprocessing,NMR T2 spectrum-based capillary pressure curve prediction and pore structure characteristic parameter extraction. In the simulation experiment,the different prediction methods are used to convert NMR T2 spectra to capillary pressure curves,and the results are compared with the measured data on the graphical interface. Pore structure characteristic parameters are finally extracted from the predicted capillary pressure curves and used to evaluate the reservoir pore structure. The simulation experiment system is easy to operate,and it can visualize the processing results for the different methods to students,which enhances their understanding and knowledge of the different models to predict capillary pressure curve and improves the teaching effect of geophysical well logging.

A virtual simulation experiment platform for 6-DOF robot is developed by combining the realistic 3D image display function of the robot simulation software V-REP (virtual robot experimentation platform) and the powerful computing ability of MATLAB program. Firstly,the robot model is built in V-REP. Then the communication mechanism and communication call mode of V-REP are introduced. Finally,the simulation of robot joint space trajectory planning and Cartesian space line planning are used to illustrate how to use the MATLAB program to realize the motion simulation of the robot inside V-REP. The robot simulation technology is used to build an interesting experimental platform,which is applied in the experimental classroom of robot basic principle. The experimental teaching mode of flipped classroom is explored to improve students’ learning interest and robot design simulation ability.

Considering the constraints of many factors such as high difficulty,high risk,high cost,irreversibility and ecological damage of timber production in logging area,the virtual simulation experiment system of forest operation technology and equipment is developed with the integration of Web graphics library (WebGL) technology,network technology and 3D simulation technology. The virtual simulation experiment including cutting area creation and main cutting analysis,logging operation technology and equipment,skidding operation technology and equipment is designed. Through the parameter variable control,operation process observation and key technology practice,students carry out skill training according to the operation procedures. The virtual simulation experiment system has good practicality,interactivity and teaching effect,which is helpful to improve students’ practical ability and innovative thinking ability. It can provide reference for experimental teaching of forest engineering and related majors.

Based on the basic principle of pulse laser radar ranging,a pulse laser radar model is built to model and simulate the emission current waveform,laser emission power,received signal power,and received light voltage waveform. The factors that cause measurement errors are analyzed,and the full waveform analysis algorithm is studied to accurately obtain the laser pulse reception time under different conditions. For single-mode echoes with high signal-to-noise ratio,the adaptive threshold method can be used and for low signal-to-noise ratios,the waveform centroid method can be adopted. This simulation and modeling can be applied to the laser radar experimental teaching and design,as well as the related scientific research.

The principle of numercial control (NC) interpolation is the teaching focal point as well as the teaching difficult of the “NC System and Principle” and “NC Technology”. For the current status of lacking experimental teaching equipment of NC interpolation principle in colleges and universities,based on the LabVIEW virtual instrument development platform,an experimental simulation teaching system of NC interpolation principle is developed. This system can achieve linear interpolation and circular interpolation computing by the point-to-point comparison method and the digital integral method in the first quadrant,and dynamically display the trajectory of the interpolation and theoretical straight line or circular arc curve in real time,which meets the needs of experimental teaching and training.

According to the teaching characteristics of the geotechnical engineering course experiment,a corresponding teaching evaluation system is established. Taking the soil mechanics course experiment as an example,a variety of synthesis algorithm models are designed using the fuzzy mathematics theory to conduct a secondary comprehensive evaluation of the experimental teaching quality. Through the reform and optimization of the curriculum teaching system,setting up a preview assessment mechanism before experimental classes,the implementation of pre-class preparation process,and the addition of virtual simulation experiment projects,students’ participation in experiments has been enhanced,and the quality of experimental teaching has been effectively improved.

With the rapid development of information technology and virtual reality technology,its application in the field of education is more and more extensive. In order to solve the problems of abstract teaching content and shortage of experimental teaching equipment in the current course of hydraulic transmission and control,a set of virtual-real hydraulic transmission and control experimental teaching platform is developed based on the current theoretical teaching content and experimental teaching equipment. Aiming at hydraulic theory course teaching and hydraulic loop experiment teaching,the platform designs three modules: structural display and virtual disassembly module,hydraulic experiment case module and field experiment module,which realize a series of functions including perspective interaction function,model selection feedback function,automatic disassembly function,fluid simulation function and so on. After the debugging and release of the platform,through a round of course verification,good operation and use effect has been obtained,which has greatly improved the teaching efficiency while optimizing the teaching system.

In order to meet the teaching and research needs of biology,chemistry and pharmacy students in the extraction and activity research of plant natural products,a comprehensive virtual simulation experiment project on the study of liver-protective activity and chemical composition of Tibetan medicine Veronicaciliata Fisch is designed using the WebGL technology,3D simulation technology and development tools such as Unity3D,Maya and Visual Studio. This project is based on the extraction and activity research of natural product in plants,closely following the knowledge of theoretical courses and real experiments and absorbing the latest scientific research results and application cases as well. Teaching practice of this project shows that the virtual training is a good way to enhance of ability of students to learn the principles and key skills in the experimental teaching. It is indicated that the virtual simulation experiment effectively expands the cognitive scope and learning space of students,creates a “virtual-real,virtual-real complementary” practical teaching mode,enables students to participate in comprehensive experimental teaching independently and deeply,and improves the ability of independent learning,innovation and comprehensive practice of students.

This article takes zinc oxide nanowires as the research object to explore the influencing factors of electron field emission from nanowires. To this end,a complete set of virtual simulation experimental schemes is proposed. The experiment utilizes computer simulation software OPERA-3D to model the zinc oxide nanowire structure,focusing on investigating the effects of factors such as the aspect ratio of nanowires,grid voltage,cathode-grid spacing,and nanowire array density on the field emission current and their underlying mechanisms. The experiments show that the aspect ratio of nanowires and the cathode-grid distance are significant parameters affecting their field emission performance. Meanwhile,reasonable control of the nanowire array density can effectively reduce the impact of field screening effects. Through this simulation experiment,students can gain a deeper understanding of the basic principles of electron field emission from nanowires and electron optics theory,improv their practical hands-on skills and cultivate scientific research thinking,and lay a solid foundation for their future studies.

Given the interdisciplinary properties of mineral materials,a comprehensive pedagogical experiment that centers on utilizing kaolinite as catalyst support for synthesizing γ-FeOOH/kaolinite persulfate catalytic composite is designed. The persulfate activation performance for the degradation of bisphenol A is investigated in a dynamic degradation system. Characterizations,such as scanning electron microscope,transmission electron microscope,X-ray diffractometer,and N2 isothermal adsorption-desorption test analysis,are employed to detect the catalyst’s microstructural,phase structures,and pore characteristics. Furthermore,the composite’s effectiveness in activating persulfate for the degradation of bisphenol A is systematically studied through the dynamic degradation system,which inspires the students’ thinking on the structure-activity relationship between structure and catalytic performance. The results show that the design of this experiment can further help students understand the research frontier of mineral materials,cultivate their scientific research thinking,improve their scientific research innovation ability and practical ability,and finally help them improve the quality of teaching.

With the Ministry of Education launching the New Engineering program in 2018,the University of Electronic Science and Technology of China has reformed a number of professional courses around the goal of the new engineering program and has achieved outstanding results. Computer Network,as a core course for talent cultivation of software engineering majors,has been drastically reformed in the form of course organization,teaching methods,and course contents. The problems existing in the traditional computer network course in terms of experimental teaching are firstly analyzed and the experimental reform of network courses in other colleges and universities is then investigated. On this basis,various measures taken by the course team in the reform of experimental teaching are introduced,including the design of new experiments,the improvement of experimental materials,and the addition of a more objective way of evaluation. Particularly,the experimental content through a variety of technologies is designed. The protocol verification experiments facilitate students’ comprehension of the protocols,the virtual simulation experiments address deficiencies in networking and device configuration,and the network programming experiments reinforce their engineering abilities in network coding. This multifaceted experimental approach not only fosters students’ interest in learning but also facilitates the integration of theory with practice,thereby enhancing their sense of learning acquisition. Finally,the experiences in the reform and outline the future work are summarized.

At present,education informatization is vigorously promoted. In view of the problems of single traditional training forms,heavy tasks,and time and space constraints,the college platform introduces the WeChat public platform into the large-scale instrument training mode to explore a new model. The practice shows that the operation of this model stimulates the initiative and innovation of students’ independent learning,and significantly improves their professional cognition,scientific research level and training quality. At the same time,the failure rate of the instrument is effectively reduced,and the use efficiency of the large instrument is improved. In addition,the operation of this mode improves the professional level and professional ability of teachers,and enhances the ability of platform comprehensive services.

Timely and accurate demand forecasting for electricity users is the foundation for effective operation of the electricity market,energy conservation and emission reduction efforts by users,and the implementation of the “dual carbon” task. However,there are some problems in traditional teaching methods for electricity demand forecasting,such as difficulties in obtaining data and large data volumes,and cumbersome calculation processes for demand forecasting leading to hard verification of trial and error. To address these issues,a virtual simulation experiment for electricity demand forecasting has been independently developed. This experiment builds a virtual experimental scenario based on real-world data from electricity users,follows the actual business processes of power sales companies,and highly simulates electricity demand forecasting activities. Through this experimental environment,students can intuitively experience,repeatedly try and correct,and conduct practical verification,thereby achieving the teaching objectives of method exploration and experience accumulation.

Under the background of engineering education certification,it is necessary to build a comprehensive practical training course for precision instrument or precision measurement system for undergraduate students majoring in mechanical engineering,intelligent manufacturing,and measurement & control majors. Coordinate measuring machine (CMM) is selected as a practical teaching platform,which is a typical precision instrument integrating “optical,mechanical,electrical and computing”. The measuring practice platform of general measuring software PC-DMIS of CMM and the offline software programming practice teaching platform are built,the teaching objectives for outcomes-based education (OBE) are defined,and the method of teaching goal achievement degree analysis are given. Several rounds of practical courses teaching have been carried out. Through practical training,students can solve complex measurement engineering problems of precision parts,master the application of general measurement software,and get familiar with its special software development. The CMM large-scale instrument practice system teaching based on OBE is helpful to cultivate students’ practice and innovation ability,and can provide reference for the construction of relevant professional practice courses.

A sample,facile,liquid phase reduction approach is developed for the synthesis of Cu2O. In this experiment,the size and morphology of Cu2O could be precisely tuned by readily changing the conditions of reaction kinetics,such as temperature and surfactant. Specially,cubic and octahedral Cu2O are successfully synthesized,respectively,together with tunable particle size in the ranged of 100 nm to 650 nm. It is found that the color of Cu2O could be altered by fine-tuning the size and morphology,due to the obvious change in absorption of light and carriers transport characteristics based on the experimental observation and characterization. The experiment establishes the relationship among synthetic parameters,microstructures,and optical properties,and it could be easily extended to innovative and comprehensive experimental teaching used for the undergraduates because of its safe and green synthesis approach,straight-forward and observable experimental phenomenon,and easy to operate. It would greatly help students understand advanced scientific issues,stimulate their interest in learning,and resolve the practical difficulties in terms of learnt knowledge.

The analysis of the composition of ancient glass on the Silk Road is helpful to understand the context of history. Due to the influence of adverse environmental conditions,the glass will be weathered,which brings difficulties to the composition analysis and classification of glass. In this paper,a comprehensive identification method is proposed,the glass composition before weathering is predicted,and the classification model is established by using voting method and K-Means method. After validation,the category classification model achieves an accuracy of 98.44% with good robustness.

“China’s education modernization 2035” has given new connotation and puts forward new requirements for the construction of experimental teaching centers in colleges and universities. This paper takes the Provincial Experimental Teaching Demonstration Center of Oil and Gas Equipment Technology of Southwest Petroleum University as an example,analyzes the existing problems of the experimental center in aspects of cultural construction,management system,training mode and teacher team,and puts forward the connotation development scheme of the experimental center based on the background of China’s educational modernization. After four years of continuous construction,the center is built into a student-centered collaborative education community of multi-orientation training,multi-disciplinary integration,and multi-track development,providing new ideas for deepening the reform of university experimental centers.

In view of the problems faced by the safety management of basic chemistry laboratories in colleges and universities,such as insufficient informatization,insufficient safety awareness of laboratory personnel,and limited investment in laboratory safety,this paper takes human management as the core and builds an efficient,convenient,flexible and low-cost security access system for basic chemistry laboratories in colleges and universities based on the Internet of Things (IoT) technology. The laboratory safety access system consists of three subsystems,namely,laboratory safety access test,laboratory access control and laboratory practice drill. In the operation of the laboratory’s security access system,the customs clearance mode is used to promote flexible and active learning of security knowledge,the IoT technology is used to support automatic real-time check-in for access control,and the combination of online and offline methods is used to complete the efficient and safe training,fully ensuring the fire safety and environmental safety of the basic chemistry laboratory. Through two years of practical application,the implementation of the system has realized the transformation of basic chemistry laboratory safety education in colleges and universities from passive assessment to active learning,and has achieved an improvement of laboratory safety management and education from the quantitative change to the qualitative change.

A discrete intelligent factory teaching platform composed of four workstations is designed for mouse battery assembly at Hebei University to meet the requirements of first-class undergraduate education and China Engineering Accreditation. A practical training course in robot principles and control is proposed and integrated with existing courses based on this platform,which improves the teaching system. The platform has also expanded the on-campus practice and training platform and achieved complementarity and integration with off-campus practice bases. It provides technical and venue support for students to participate in competitions,guiding students to actively engage in learning and knowledge accumulation. This practice indicates that the construction of the discrete intelligent factory teaching platform is conducive to cultivating students’ practical ability to solve complex engineering problems and their exploration ability and creativity,enhancing students,engineering literacy,and promoting the cultivation of first-class undergraduate talents.