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When the loss of coolant accident happens in a reactor, because of the high temperature and high pressure in the reactor and the low external pressure, the critical flow may occur at the break due to sharp depressurization and vaporization. The critical flow characteristics have a great impact on the accident process, and the accurate estimation of critical flow at the break is more important for the safety analysis of the supercritical water reactor. In order to obtain the critical flow characteristics under supercritical conditions, the steady state tests of critical flow were systematically carried out under supercritical pressure in a nozzle test section with a diameter of 2 mm and a length diameter ratio of 1-20, taking supercritical CO2 as the working fluid. The test pressure range was 7.4-9.5 MPa and the temperature range was 15-55 ℃, a large number of reliable test data were obtained from the test. The effects of stagnation pressure, stagnation temperature and nozzle length diameter ratio on critical flow were obtained. That is, when the pressure is constant, the critical flow decreases with the increase of inlet temperature, and the critical flow drops sharply at the beginning, but when the inlet temperature is higher than a certain value, the critical flow changes little with the increase of stagnation temperature. The turning point of flow rate changing with temperature is about the pseudo critical temperature of the corresponding pressure. The higher the stagnation pressure, the greater the critical flow. The influence law of stagnation temperature and stagnation pressure on critical flow is basically consistent with the change law of critical flow of water. For short nozzle and medium long nozzle, the influence of length diameter ratio is small. For long nozzle, due to the greater influence of friction resistance, the flow is much smaller, but the higher the stagnation temperature, the higher the stagnation pressure, the smaller the influence of the length diameter ratio. The obtained experimental data complements the critical flow experimental databases and provides experimental data for the development and verification of the critical flow model. With the obtained supercritical CO2 test data, the universality and accuracy of the general thermal equilibrium discharge flow model are further verified, which is applicable to the critical flow of supercritical CO2 and can better predict the critical flow under supercritical conditions.

To solve the problem that the existing YOLOv3 algorithm had more false detections and missed detections for traffic sign detection task with small target problems and complex background, based on the YOLOv3, a channel attention method for target detection and a spatial attention method based on semantic segmentation guidance were proposed to form the YOLOv3-A (attention) algorithm. The detection features in the channel and spatial dimensions were recalibrated, allowing the network to focus and enhance the effective features, and suppress interference features, which greatly improved the detection performance. Experiments on the TT100K traffic sign data set show that the algorithm improves the detection performance of small targets, and the accuracy and recall rate of the YOLOv3 are improved by 1.9% and 2.8% respectively. [ABSTRACT FROM AUTHOR]

During the development and procession of liver fibrosis, peroxisome proliferator - activated receptor (PPAR) &$945; and γ are in charge of the regulation of lipid metabolism, fatty acid metabolism, anti - liver fibrosis, etc., and are closely related to fat metabolism - related enzymes. As a key enzyme in fat metabolism, acyl - CoA synthetase long - chain family member 1 (ACSL1) is involved in lipid synthesis and catabolism and then causes lipid deposition and inflammation in the liver, so it directly or indirectly promotes hepatic fibrosis. The biological functions and roles of PPAR α and γ and ACSL1 are reviewed ; the action mechanisms of PPAR a and Y in the transcriptional regulation of ACSL1 are briefly described ; the regulatory effects of PPAR a and Y on ACSL1 and their effects on the progression of hepatic fibrosis are analyzed from the aspects of liver lipid metabolism and hepatic stellate cell activation. It is pointed out that in the liver PPAR a and γ are directly or indirectly involved in the progression of hepatic fibrosis by regulating ACSL1. [ABSTRACT FROM AUTHOR]

During the development and procession of liver fibrosis, peroxisome proliferator - activated receptor (PPAR) a and Y are in charge of the regulation of lipid metabolism, fatty acid metabolism, anti - liver fibrosis, etc., and are closely related to fat metabolism - related enzymes. As a key enzyme in fat metabolism, acyl - CoA synthetase long - chain family member 1 ( ACSL1 ) is involved in lipid synthesis and catabolism and then causes lipid deposition and inflammation in the liver, so it directly or indirectly promotes hepatic fibrosis. The biological functions and roles of PPAR α and β and ACSL1 are reviewed ; the action mechanisms of PPAR α and β in the transcriptional regulation of ACSL1 are briefly described ; the regulatory effects of PPAR α and βon ACSL1 and their effects on the progression of hepatic fibrosis are analyzed from the aspects of liver lipid metabolism and hepatic stellate cell activation. It is pointed out that in the liver PPAR α and βare directly or indirectly involved in the progression of hepatic fibrosis by regulating ACSL1. [ABSTRACT FROM AUTHOR]

The paper introduces professor WANG Haidong 's clinical experience in treatment of wrist rheumatoid arthritis with acupotomy mobilization at the muscle regions (sinews/fascia) of three yang meridians of hand. Professor WANG Haidong believes that wrist rheumatoid arthritis belongs to the disorder of meridian muscle regions and is especially associated with the damage of the muscle regions of three yang meridians of hand running through the wrist. Under the guidance of meridian muscle region theory, on the basis of modern anatomy, and the treatment principle, "needling the affected areas may treat disorders of sinews/fascia and dysfunction of meridians simultaneously", acupotomy mobilization is adopted to balance sinews/fascia and bones, operated directly at the involved meridian muscle regions. Besides the foci (palpable knotted sites) on the distribution of muscle regions, acupoints along the affected meridians are stimulated in combination. With this therapy, after determining the location of illness, both the disorder of sinews/fascia and that of meridians can be treated.