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In order to meet the needs of accurate traceability of dose monitoring instruments in domestic medical, security inspection and other pulse radiation places, a 50-120 kV millisecond pulse X-ray reference radiation field that meets the requirements of norms and standards was established, based on the gate control technology, and its pulse width can be adjustable in the range of 1-6 300 ms. The pulse X-ray reference waveform was established by studying and testing the tube voltage stability, dose linearity, repeatability, pulse waveform and other key parameters of the radiation field, and the pulse dose rate was measured using a cylindrical ionization chamber with a sensitive volume of 30 cm3, and obtained the following research results: when the tube voltage was preset to 60 kV, the relative deviation of the intervened and non-intervened measuring tube voltage did not exceed ±1.5%; the minimum pulse width of the reference waveform pulse output was 20 ms, and a 95% uniform radiation field with a diameter of about 5.5 cm could be generated at 1 m. Moreover, the dose rate range of N series and RQR series radiation quality was extended to 0.002-10 mGy/s and 0.03-250 mGy/s, respectively, which can be used for the metrological traceability of protective instruments.

Human eye lens is an organ vulnerable to radiation damage. Through self-developed human skull model, a spherical ionization chamber was embedded in the ball to directly measure the eye lens individual dose equivalent Hp(3). Aiming at the accuracy evaluation of Hp(3) in radiation environment, the following research was carried out in this paper: Firstly, the instrument was calibrated under the S-Cs γ-ray radiation quality condition specified in the GB/T 12162.1 standard, and a calibration factor was obtained, NH=1.19 μSv/pC. Then, the correction factors k(E,α) were determined under different energy and incident angle conditions. At the same time, the background current and polarization effect were experimentally measured. Without the correction of energy and incident angle, the relative error of the energy response was -0.9%-12.6% in the energy range of 33 keV-1.25 MeV, and the relative error of the angle response was -7.9%-0% in the range of -60°-60°. At the same time, the factors affecting the accuracy of the measured value of the chamber were discussed. The relative expanded uncertainty of the calibration factor was 5.6% (k=2); when the energy and incident angle were known and unknown, the relative expanded uncertainty of the measured value of Hp(3) were 9.4% (k=2) and 18% (k=2) respectively. For radiation fields with unknown energy and incident angle, the Hp(3) value in the radiation field can be obtained directly by using the ionization chamber within the uncertainty range. This study can provide a reference for the accurate measurement of individual dose equivalent of eye lens.

In order to accurately measure the environmental level dose rate, based on the G(E) function method and conversion of complete spectra without deconvolution method, the energy spectrum and dose rate of X/γ ray was measured for calculating spectrum-dose conversion coefficient. And finally the conversion of energy spectrum to dose rate is realized. The residual difference between the calculated dose rate by the energy spectrum-dose method and the measured dose rate value is approximately 0, which proves that the method is self-consistent. Experiments have been conducted in 137Cs and 60Co radiation fields, and the maximum relative error of dose rate is ±10%, which proves that the G(E) function method and Conversion of complete spectra without deconvolution method are feasible for energy spectrum-dose conversion.

Solid–liquid organic phase-change micro/nanocapsules are potential candidates for energy storage. Recently, significant progress has been made regarding phase-change micro/nanocapsules in terms of their synthesis, properties, and applications. Extensive research has been conducted to enhance their thermal properties, such as thermal storage capacity, thermal conductivity, and thermal reliability. However, factors that influence the thermal properties of micro/nanocapsules have received little attention. This study presents a comprehensive review of phase-change micro/nanocapsules focusing on their thermal properties and their influencing factors. In addition, the thermal properties of the major solid–liquid organic pure phase-change materials are summarized. Furthermore, common micro/nanoencapsulation methods and their influence on the thermal properties were analyzed. Finally, the potential applications of these phase-change micro/nanocapsules were also investigated. This study was devoted to enhancing the thermal properties of micro/nanocapsules, which play a crucial role in their practical applications. [ABSTRACT FROM AUTHOR]

Objective To investigate the changes of the upper airway shape and respiratory function in patients with mild and moderate obstructive sleep apnea⁃hypopnea syndrome (OSAHS) before and after wearing mandibular ad⁃ vancement snore stopping devices (MASSD), providing a reference and basis for the treatment mechanisms and clinical efficacy of MASSD for patients with mild and moderate OSAHS. Methods Sixty patients who were diagnosed with mild and moderate OSAHS by polysomnography were selected. Snoring frequency, the apnea hypopnea index and lowest oxygen saturation in 60 patients before and after treatment were compared. The patients’upper airways were scanned by CBCT before and after wearing MASSD. In Vivo Dental software was used to reconstruct the three⁃dimensional shape of upper airway. The upper airway sagittal diameter, the coronal diameter, the minimum cross⁃sectional area and the vol⁃ ume of each segment were measured. The snoring frequency, the apnea hypopnea index and the lowest oxygen satura⁃tion were compared before and after treatment. Results Before wearing MASSD, the snoring frequency, the apnea hy⁃ popnea index, and the minimum oxygen saturation of 60 patients were [946 (542,1 010)], (20.61 ± 5.19), and (78 ± 8)%, respectively. After wearing MASSD, the snore frequency [19(11,30)] and the respiratory disorder index (10.86 ± 4.31) decreased significantly and the minimum oxygen saturation increased (92 ± 3)% . Compared with before wearing MASSD, no statistically significance differences were detected (P > 0.05) except for the sagittal diameter and coronal di⁃ ameter of the surface of the palatum durum. The sagittal diameter and the coronal diameter of each plane of the airway increased, and the minimum cross⁃sectional area of each section of the airway and the volume of each section of the air⁃ way displayed varying degrees of significant increases (P < 0.001) after wearing MASSD. Conclusion Wearing MASSD can open the airways of patients with mild and moderate OSAHS and increase the airway volume of the upper airway to improve the respiratory function.

The quality of broadband power line carrier communication mainly depends on the carrier communication frequency. However, there is a lack of fast and effective optimal carrier frequency selection method. One frequency selection method based on frequency point optimization neural network is proposed by this paper. This method combines transmission line theory and voltage partial reflection theory to build a power line carrier channel mathematical model of the distribution network. The input frequency point sample set is used as the training set of the frequency point optimization neural network to obtain a neural network model that can predict the local optimal frequency point set. Then the actual distribution network is taken as an example for simulation analysis. When inputting any frequency range, the model outputs the corresponding optimal frequency point set. Simulation results show that the algorithm saves a lot of input impedance or channel strength testing time, while the error rate is limited to about 3%.

Gastric cancer (GC) is associated with high morbidity and mortality rates. Thus, early diagnosis is important to improve disease prognosis. Endoscopic assessment represents the most reliable imaging method for GC diagnosis; however, it is semi-invasive and costly and heavily depends on the skills of the endoscopist, which limit its clinical applicability. Therefore, the search for new sensitive biomarkers for the early detection of GC using noninvasive sampling collection methods has attracted much attention among scientists. Urine is considered an ideal biofluid, as it is readily accessible, less complex, and relatively stable than plasma and serum. Over the years, substantial progress has been made in screening for potential urinary biomarkers for GC. This review explores the possible applications and limitations of urinary biomarkers in GC detection and diagnosis., Competing Interests: No potential conflict of interest relevant to this article was reported., (Copyright © 2022. Korean Gastric Cancer Association.)