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This article explores the impact of digital technological advances on international trade exchanges, notably regarding trade costs and barriers. The article first constructs a trade development measurement model for global trade costs and barriers, and analyzes in detail the development quality of international trade using a threshold effect model. In addition, a model for the development potential of international trade is constructed, and the evolution of its spatial pattern is investigated through global and local Moran indices. The empirical Analysis shows that the regression coefficients of economic level, trade potential and trade barriers are 0.228, 0.661 and −0.110, respectively. Analyzing from a macro perspective, the development quality of China’s international trade shows an upward trend between 2012 and 2022, with an overall improvement of about 38 percentage points. This result indicates that improving economic level and trade potential helps to promote the improvement of the development quality of international trade. In contrast, trade barriers may have an inhibiting effect on the development of international trade. By scientifically calculating the quality of international trade development and data visualization of its development process, the article provides effective ways and methods for the Analysis and research of international trade development.

This paper takes the experimental design of the flipped classroom teaching mode under digital information technology as the entry point, chooses the appropriate research object and method, and designs the experimental program of flipped classroom teaching in college sports. Since the teaching effect of the flipped classroom teaching mode needs to be supported by students’ movement data, this paper utilizes the least squares distance to match and retrieve the data of students’ movement postures and then combines it with the ANN model to deeply mine the students’ movement data. For the teaching effect of the flipped classroom teaching mode, innovative practices are carried out for physical education teaching in colleges and universities. The results show that when the linear correlation coefficient of the ANN model is 1, the lowest value of validation loss is 2.1*10−4. The flipped classroom teaching mode can effectively enhance students’ physical fitness. The mean value of students in the experimental group in the learning motivation dimension has been improved by 5.44 points compared with the preexperimentation period. The results of the T-test of the sports concern and learning satisfaction are all significant differences at the 1% level. The combination of flipped classrooms and college physical education teaching in a digital environment can improve the effectiveness of physical education teaching and increase students’ interest in physical education learning.

The purpose of the work is to research the planar source of 14C with large size by the absorbability of the anodizing membrane. The adsorption of 14C on the anodizing membrane with thickness of 4 to 12 μm were investigated. The adsorption of 14C and the uniformity of the planar source were investigated on the volume of 14C solution. The specific activity of 14C was investigated on adsorption of 14C. The fastness, the uniformity and the surface emission rate of the planar source of 14C were measured. The result shows that the uniformity of the planar source (100 mm×150 mm) of14C is precede 10%. The plateau length is 400 V, the slope of the plateau is 0.3% per 100 V. The threshold correction is 0.2%. The uncertainty of 14C source measurement is 2% (k=2). The technical parameters of the developed plane source 14C can meet the requirements of relevant standards.

To develop anodizing devise of 20% sulphuric acid for the preparation of the source of nonmetal nuclide, the process paramenters of the anodizing membrane were studied, the adsorption performance of radionuclide 14C was verified, and a new method for the preparation of the plate source of nonmetal nuclide was developed. The influence of several parameters including temperature, volt and time to the thickness of the anodizing membrane were investigated within 14-20 ℃, 10-22 V and 20-150 min. The result shows that the thickness of the anodizing membrane produced by the process is within 4-60 μm and the uniformity of the thickness is precede 7%. The absorbent of the anodizing membrane within 4-12 μm is over the 75% to the 14C. The research can provide a new method for the developing of the plane source of nonmetallic nuclide.

BackgroundLiquid metal sodium is used as coolant in China Experimental Fast Reactor (CEFR), the radioactive sodium aerosol in primary loop cold trap process needs to be monitored, so that the corresponding protective measures can be taken in time to ensure the health and safety of the staff. To ensure the accuracy of the monitoring results, it is necessary to calibrate the radioactive sodium aerosol monitor regularly.PurposeThis study aims to propose an effective method for the calibration of radioactive sodium aerosol monitor.MethodsA special radioactive aerosol membrane source was designed and applied to calibrating the radioactive sodium aerosol monitors. The response, relative error, and repeatability of the monitor were studied separately, and the uncertainty of the calibration factor was evaluated.ResultsThe results show that the uncertainty of response factor is 5% (k = 2).ConclusionsThis calibration method is suitable for the calibration of radioactive sodium aerosol monitors, and meets the requirements for traceability of the monitors.

To separate short-lived nuclide Cs or Rb from fission products,the separation could be started from their parent nuclides (Xe or Kr). A setup with frozen cold trap is designed to separate such kinds of inert gas nuclides. The principle is based on that different gases have different saturated vapor tensions. With isotopic exchanging technology,the setup has been applied successfully in the separation of Cs or Rb from complicated fission products. Decontamination factors of main γ-emitters are higher than 1 × 10. [ABSTRACT FROM AUTHOR]

Radioactivity measurement of short-lived nuclides is the basis of decay data measurement, which requires rapid separation and purification of the interested nuclides from complicated fission products. A rapid separation system based on SISAK and extraction chromatography technique was established to isolate Y, which half-life is 10.3 min. With the best conditions studied in this paper, Y was separated successfully from complicated fission products under the mini-reactor in the China Institute of Atomic Energy. Decontamination factors to other nuclides except Y are higher than 2 × 10. [ABSTRACT FROM AUTHOR]

The article informs that the first topology paper in China was published by Kiang Tsai-hai in 1931.

The article discusses the term "Suanbiao Hebi" which is believed to be the first collection of modern integrated science tables designed for new model schools in China. It was first printed in 1902 which was found to be rich in content and covering seven categories. It describes that the tables where 51 in number including one on astronomy, geography and mathematics.

To introduce 3D printing technology into the field of radiation source preparation and make up for the lack of precision special-shaped radiation source preparation technology at home and abroad. The photosensitive resin for 133Cs 3D printing was prepared by studying the phase transfer method and detected by ICP-MS to explore the preparation conditions. Then, the photosensitive resin material for 137Cs 3D printing was prepared and detected by lanthanum bromide detector. The results show that the uneven distribution of cesium in three photosensitive resins for 133Cs 3D printing and 137Cs 3D printing prepared by phase transfer method was less than 5%. As a simple and mild method, phase transfer method can be used to prepare photosensitive resin for 3D printing containing cesium, and has certain universality.

To study the new type of dosimeter with a dose up to the ultra-high dose range of MGy, the electron spin resonance (ESR) method is used to measure the signal intensity of the sample irradiated by gamma rays or electron beams. Preliminary studies have been carried out through the selection of sensitive materials, linearity after irradiation, and stability. The results showed that the quartz can be used as a raw material for ultra-high dosimeters. After 15 min 300 ℃ proper heat treatment, the signal intensity of the irradiated quartz sample can maintain good stability within one year with a change of less than 3%. The radiation dose and the E′ signal intensity of quartz are proportional to the dose range of 10-103 kGy. The fitting coefficient is above 0.99. Compared with the high-purity quartz sample without heat treatment, the stability and R2 of fitting function of quartz sample are significantly improved. Therefore, the quartz dosimeter is suitable as a working dosimeter in the ultra-high dose range.

I-131 is an important artificial radionuclide and an important detection object in nuclear facilities. The current mainstream method is to use a uniformly distributed Ba-133 source instead of an iodine source to calibrate the I-131 detection instrument. However, in the process of value transmission, the distribution of the I-131 calibration standard source directly affects the setting value of the standard source and affects the calibration of the testing instrument. The plane source is used to determine the detection efficiency at different depths, and the depth efficiency curve is established. The fitting result is η(x)=0.007 655e-0.020 6x. Therefore, the activity efficiency equation of I-131 was established through mathematical analysis, and the positive and negative measurement results were used to solve it to determine its activity distribution. The distribution of the three I-131 sources is uniform distribution, exponential distribution and plane distribution. The deviation of exponential distribution source is between the deviation of the positive and negative measurement results of the uniform distribution source，which does not exceed 1%，and the deviation of the positive and negative measurement results of the planar distribution source，which exceeds 50%. By judging the quick solution of the source distribution, it is easy to prepare the calibration standard source and establish the on-site calibration process.