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【Objective】With the rapid development of the satellite Internet of Things (IoT), a large number of short-burst users are aggravating collisions and interference among users of the access network. To address this issue, several organizations and individuals have put forward some dynamic access schemes. However, for most of the proposed dynamic access schemes, it is necessary to know the exact number of future time slot access applications. At present, some load estimation schemes have been proposed in the literature, but the accuracy of these schemes is not high, and they can only achieve load estimation for current time slot.【Methods】To solve this issue, we propose a load estimation method based on the leading code state and parameter estimation. A load prediction method based on machine learning is also proposed. The load estimation method based on leading code status and parameter estimation analyzes the relationship between the probability of leading code in different states within the time slot of the satellite IoT and the number of requests for access to the current time slot. It gives the maximum likelihood parameter estimation expression and uses the maximum likelihood parameter estimation method to estimate the current time slot load. The load prediction method based on machine learning takes the estimated load value as its historical data, combining the Long and Short Term Memory (LSTM) network and the Auto Regressive Moving Average (ARMA) model to predict the future time slot load.【Results】The simulation results show that the estimated error of the load estimation method based on leading code state and parameter estimation is less than 1%. The comprehensive error of the load prediction method based on load estimation results as historical machine learning data is about 6%.【Conclusion】The predicted error of the proposed load estimation and prediction method is within the acceptable range, thus offering accurate future slot access requests for dynamic access schemes.

Objective As the development and utilization of urban underground space advances towards the three-dimensional and multi-dimensional direction, there are more and more over-crossing and under-crossing urban rail transit projects. Among them, the close under-crossing construction of new stations with large cross-section has a significant impact on the surrounding environment. Therefore, it is urgent to carry out an in-depth study on the ground settlement and deformation law of existing stations during the new station construction process closely under-crossing existing stations by Pile-Beam-Arch (PBA) method. Method Based on the actual engineering case of Beijing Metro Line 6 Pinguoyuan Station, which closely under-crosses the existing station with same name on Metro Line 1, the law of ground settlement and deformation of the existing station is analyzed by adopting numerical simulation method in the study. By comparing the actual monitoring data, the actual situation of ground settlement and deformation of the existing station during the construction process is further verified, and the numerical simulation results are compared and analyzed with the measured data. Result & Conclusion The most unfavorable stages for ground settlement and existing structure deformation are the guide hole excavation stage and the second lining arch stage of PBA method. After the completion of second lining arch construction, both the ground settlement and the deformation of the existing structure show rebound phenomenon. In addition, the stiffness of the existing station has a significant inhibiting effect on the ground settlement above, which is manifested in the fact that the ground settlement value of the overlapping section is smaller than that of the non-overlapping section. The deformation of the existing station structure caused by new station constructed with PBA method is mainly the rigid body displacement, while it caused track structure deformation is mainly the overturning deformation, which is locally manifested as rigid body displacement.

No intervention definitively extends transplant-free survival in primary sclerosing cholangitis (PSC). Statins, inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR), may enhance PSC prognosis, but their efficacy is debated.

Objective Construction disturbances from nearby excavation of foundation pit can cause significant deformation of existing stations in operation, thereby affecting the normal operation of trains. Therefore, it is necessary to study the influence of foundation pit excavation in vertically incremental layers on existing stations located below. Method Taking the construction project of Beijing Subway Line 6 Pingguoyuan Station three-level-section foundation pit as example, the Midas GTS NX finite element software is used to build a foundation pit model. The deformation law of existing station structures caused by deep foundation pit excavation in vertically incremental layers is analyzed, and the simulation results are compared with field monitoring results. Result & Conclusion With the progress of foundation pit excavation, the vertical deformation of existing station structures continuously increases, and the deformation curve of the roof plate exhibits a normal distribution. The mid-span deformation of the station roof is greater than the edge-span deformation, and the vertical deformation at station top is greater than that at the bottom. When the distance between the selected station section and the foundation pit exceeds 9.7 m (approximately 0.81 times the excavation depth), the differential deformation between edge-span and mid-span roof plates disappears. A comparison between numerical simulation data and actual monitoring results reveals that the deformation law of existing stations obtained from numerical simulation analysis is consistent with actual monitoring results, and the maximum deformation is less than the control value of 10.0 mm.

Liver fibrosis is a type of chronic pathological liver damage involving liver tissue hypoxia and abnormal extracellular matrix deposits. Hepatic stellate cells (HSCs) activation is critical for liver fibrosis. Currently, inhibiting HSCs activation or inducing HSCs ferroptosis is considered an effective strategy for the treatment of liver fibrosis. Sarcoma protein kinase (Src) is an important member of the tyrosine protein kinase family. Hypoxia causes Src phosphorylation at tyrosine 416 (Tyr 416), and inhibiting Src activation can alleviate liver fibrosis. There is currently little research on the relationship between Src activation and ferroptosis in liver fibrosis. 1-(1,1-Dimethylethyl)-1-(4-methylphenyl)-1H-pyrazolo[3,4-d]pyrimidin-4-amine (PP1) is an inhibitor of Src activation at Tyr 416. Therefore, in this study we treated HSC-T6 cells with PP1 under normoxic and hypoxic culture conditions; moreover, PP1 was also used to treat a carbon tetrachloride-induced mouse liver fibrosis model. We explored whether inhibiting Src activation could alleviate liver fibrosis by promoting HSCs ferroptosis in vitro and in vivo. In vitro experiments showed that inhibiting Src activation in HSC-T6 cells significantly reduced hypoxia-inducible factor-1α (HIF-1α) expression and HSC-T6 cells activation, and ferroptosis was significantly increased. In vivo experiments revealed that inhibiting Src activation in fibrotic livers reduced HIF-1α expression; meanwhile, ferroptosis was promoted, and liver fibrosis was alleviated. Therefore, inhibiting Src activation, which increases HSCs ferroptosis, can alleviate liver fibrosis.

In modern clothing design, quilting as a means of emphasizing pattern decoration and enriching fabric texture form, its application has presented a diversified and diversified trend. This paper utilizes the montage technique in the process of designing patchwork clothing. The cultural elements of quilted clothing are being innovated through the use of the unique creative art technique of montage. Patchwork clothing design and montage techniques are cross-analyzed to explore the commonality of the two in creative techniques and artistic expression. In order to objectively measure the design effect, AHP is used to determine the weights of the indicators, and then TOPSIS is used for the comprehensive evaluation, which is constructed into a comprehensive evaluation model of quilted apparel design integrating the montage technique. The design evaluation results were achieved by combining the consistency test of the model and the hierarchical total ranking. According to the hierarchical analysis method, the weights of the secondary indicators are calculated, and practicality (25.46%), comfort (20.96%), and functionality (15.37%) rank in the top three, which have a greater impact on the effect of quilting garment design incorporating the montage technique. When the two techniques are applied to apparel design, the understanding and application of practicality, comfort, and functionality should be deepened.

The arc is generated upon contact breaking-off resulting in surface erosion in the terminals and affecting the performance of electrical contact. As there is no natural zero crossing point in the DC power supply system, the erosion caused by arcs is often more severe in DC contactors than that in AC contactors. The arc erosion effect on the contact terminals is analyzed in this paper. Based on the theory of magnetohydrodynamics, a dynamic coupling model of arc and contact terminals considering energy coupling is established. Then, the impacts of the electric current level and breaking speed on the arc erosion in contact terminals are studied by using the model. Simulation results show that the arc temperature near the anode is higher than that near the cathode. It can be noted that the arc temperature and arcing time rise significantly by increasing the current from 20 A to 30 A, which improves the arcing energy by 75.93% and thus worsening the contact erosion. Simulation results also indicate that increasing the breaking-off speed from 0.1 m/s to 0.2 m/s, results in an increase of voltage and current variation rates, an reduction of the arcing time and molten pool volume, a decrease of the arcing energy by 47.83%, and an reduction of the impact of arc erosion on the contact terminal. The experimental results are consistent with the simulations confirming the accuracy of the simulation model.

This paper expounds the emergency disposal technology based on mapping knowledge domain, dynamically integrates the mapping knowledge domain and emergency disposal plan, and uses data fusion technology to integrate multi-source heterogeneous data to construct the mapping knowledge domain of fire and coupling disasters, disaster management graph and supervision department graph. The mapping knowledge domain technology is used to establish a multi-department emergency response plan generation model with dynamic injection of data and process, realizes the cross-department and multi-agent efficient dynamic collaborative emergency response method, and provides data basis and auxiliary decision support for the generation of emergency plans.

Aiming at the problems of poor real-time ventilation monitoring, lack of remote regulation of ventilation facilities, complex and inefficient air volume regulation process in Hulusu Coal Mine, in order to realize the controllability, visualization and intelligence of air volume regulation, the construction of intelligent ventilation facilities such as accurate air volume measurement device and remote regulation air window, including ultrasonic wind speed sensor and full section wind measuring station, has been carried out in terms of functions, the integrated ventilation intelligent control system of Hulusu Coal Mine is designed and constructed, which realizes the real-time synchronous monitoring of mine air volume, remote regulation of air volume and fault diagnosis of ventilation system, and has the functions of ventilation equipment management, data management, early warning management, authority management and remote control.

ObjectiveTo determine the quality of life among HIV-infected individuals and risk factors in Jing’an District of Shanghai.MethodsThis is a cross-sectional study. Cluster sampling strategy was used to select HIV-infected individuals who were registered with the national HIV/AIDS case reporting system in eight community health service centers in Jing’an District of Shanghai. The short form 36 （SF-36） scale， self-rating anxiety scale （SAS）， social support scale （SSS） and specifically designed questionnaires were used to collect information. Logistic regression was used to determine the factors associated with quality of life.ResultsIn total， 365 HIV-infected individuals were included in the study. The total average score of quality of life was 79.5±10.4. The scores in general health， vitality and emotional well-being were lower than the norm， whereas the scores in other dimensions were higher than the norm. Multivariable logistic regression indicated that age of 45‒ years （vs age of 18‒ years： OR=0.23， 95%CI： 0.08‒0.68） was significantly associated with the quality of life. Furthermore， smoking （OR=2.18， 95%CI： 1.22‒3.90）， lower CD4+T cell counts （

In order to meet the influent water quality of reverse osmosis membrane (RO) or nanofiltration membrane (NF) in the water reuse system of printing and dyeing wastewater, and to cope with the impact of actual printing and dyeing wastewater quality and water quantity, a new type was developed and submerged high-strength membrane filtration (HMF) technology for wastewater treatment compared with the traditional membrane bioreactor (MBR) technology. The combined effect of the process was investigated. The results show that compared with the traditional MBR technology, the membrane flux increased from 11~13 L/ (m2·h) to 14~16 L/ (m2·h), and the reflux rate is reduced from 250%~300% to 20%. The water quality of the HMF process is better than that of the MBR process, especially suspend solid, as low as 1 mg/L, which effectively guarantees the influent requirements of the subsequent RO/NF. The pollution level is relatively low, which is conducive to long-term stable operation. At present, the technology has been demonstrated and applied in the advanced treatment of wastewater in the printing and dyeing industry, and has a good promotion prospect.

ObjectiveTo investigate and analyze the epidemiological characteristics of a wild mushroom poisoning event in Qinhuangdao City, identify the species of poisonous mushroom, summarize the experience of investigation and treatment, and put forward prevention and control measures, and provide reference for the treatment and prevention of wild mushroom poisoning patients.MethodsThe poisoning events were analyzed by using the method of epidemiological investigation, morphological identification and mushroom toxin detection.ResultsFour villagers in Qinhuangdao city had nausea, abdominal pain, diarrhea, sweating and shivering after eating wild mushrooms. Patients were treated with vomiting, gastric lavage, atropine and other symptomatic treatment in the hospital, and the prognosis of the patients was good. After morphological identification and toxin detection, it was determined that food poisoning caused by mushroom of inocybe.ConclusionThis is the first reported poisoning event caused by mushroom of inocybe in Hebei Province. The reason of poisoning was misguided by the Internet and poor self-awareness of food safety. Therefore, publicity and education should be strengthened, enhancing the awareness to prevent the poisoning of wild mushroom.

Aiming at problem that dictionary learning method was poorly effective in reconstruction of mine image with noise and complex environment, a super-resolution reconstruction method of mine image based on online multi-dictionary learning was proposed. The method uses K-means clustering algorithm to divide image training set into multiple kinds of images, and trains multiple sets of high-resolution dictionaries and low-resolution dictionaries for different kinds of images, so as to improve feature representation ability of the dictionaries for complex environmental images. According to non-local self-similarity of image, non-local constraint is introduced to further constrain solution space of sparse coefficient, and online dictionary learning is used to optimize the dictionaries in the multi-dictionary learning stage, so as to improve accuracy of sparse coefficient solution and anti-noise interference ability of image reconstruction process. The experimental results show that the method can effectively improve quality of reconstructed image, suppress image blocking effect and edge jagged effect caused by noise, enhance image details, and achieve better visual effect.

The explosive welding technology of titanium alloy Ti6Al4V/aluminum alloy 7075 is the most valuable research problem in the field of Ti/Al explosive welding. In this paper, the smooth particle hydrodynamics and molecular dynamics algorithms are used to conduct multi-scale numerical calculations on the explosive welding of Ti6Al4V and 7075. The interface morphology, interface atomic movement, lattice changes and crystal defects are comprehensively analyzed. With the calculation as a reference, the Ti6Al4V/7075 composite with a flat interface is prepared. The calculation results indicate that with the transformation of titanium aluminum crystal structure, a large number of various dislocations, mainly 1/6〈110〉dislocations, are generated on the titanium side; During explosive welding, uniform and stable element diffusion occurred. Element diffusion mainly occurred in the unloading stage when the pressure was 0. The melting zone and ablation zone were composed of TiAl and TiAl _3 , respectively; The fundamental reason for the combination of Ti6Al4V/7075 is the diffusion of elements and the solid-phase binding of atoms.

BackgroundBetatrons are widely used in non-destructive testing, cargo and vehicle security inspection systems, whilst the filament power supply is an important core component of small size betatron. Existing filament power supplies are not suitable for small size betatron.PurposeThis study aims to develop a novel electron gun filament power supply for small size betatron to produce optimal radiation intensity.MethodsAn electron gun filament power supply composed of a filament duty cycle adjustment circuit and an injection current feedback circuit were designed on the basis of operating characteristics of a small size betatron. Two pulse-width modulation (PWM) signals were output from the digital signal processor (DSP) to drive the half-bridge circuit. Positive and negative alternating voltage pulses were output by the half-bridge circuit to the primary of the isolation transformer, and the secondary voltage of the transformer was loaded to the filament for heating of the filament. By collecting the betatron tube wall current and target current as the injection current feedback signal, the duty cycle of the filament voltage pulse was adjusted by DSP according to the feedback signal, and realizes the adjustment of the filament emission current, so that the current injected by the filament into the acceleration tube was kept at the optimal value.ResultsThe experimental test results show that the filament power supply can keep the betatron output dose rate in the best state, and the output dose rate stability is better than 11.3%/10 min.ConclusionsThe filament power supply meets the requirements of small size betatron with advantages of good stability, wide adjustment range and small size. It can be applied to the small size betatron developed by the Engineering Research Center for Nuclear Technology Application of the Ministry of Education of East China University of Technology.

BackgroundBetatrons are widely used in non-destructive testing, cargo and vehicle safety inspection systems.PurposeThis study aims to develop a mian control system of electron induction accelerator for the domestic production of small size betatron, and evaluate its imaging performance. Main control system was developed, including excitation power circuit, electron injection circuit, electron capture circuit and electron displacement circuit.MethodsThe inductor-capacitor parallel (LC) resonant circuit composed of excitation winding and capacitor bank was employed for excitation power circuit to generate a magnetic field that accelerates electrons steadily at the air gap of the electromagnet. The electron gun was applied to electron injection circuit for providing the electron source, and pulling the electron into the acceleration cavity. The electron capture efficiency was improved by a pulse assisted magnetic generated by field electron capture circuit, and the pulsed magnetic field was applied to the electron displacement circuit to instantaneously increase the central magnetic flux for deflecting the electron beam from the equilibrium orbit to the target to produce bremsstrahlung radiation.ResultsThe test results show that the generated X-ray steel penetration reaches 276 mm, the air wire detectability is 2 mm, the spatial resolution is 3 mm, and the contrast sensitivity meets the imaging requirements.ConclusionsThe developed control system and radiator can satisfy cargo and vehicles radiographic inspection system.

Most of the previous literatures of the transmission line inspection robot along the ground wire tend to focus on the obstacle-surmounting method and motion characteristics. There is less research on the mechanics calculation of the corresponding ground wire. Most of the existing robots are designed with the wheel-claw mechanism. There is less research on other types of robots. A caterpillar track robot along the ground line is designed in this study. The optimisation design of the obstacle-surmounting method is carried out. The typical 500 kV transmission line model is established. The stress of the ground wire in the process of robot moving along the ground wire is calculated and analysed under different control climate conditions with the help of the finite element method. The results show that the stress of the ground line has a certain safety margins. However, it may exceed the safety range under harsh climate conditions when the transmission line has heavy gradient. The inspection robot operations need reasonable planning according to the calculation results and the transmission line conditions.

BackgroundIn the exploration of uranium resources, the prompt fission neutron logging method saves the exploration cost and improves the detection efficiency with its advantage of directly measuring uranium. However, this method is greatly affected by the moderation and absorption of source neutrons by the formation environment, and must be corrected on site.PurposeThis study aims to reduce the impact on the caliper variation for prompt neutron well logging by making use of the capture γ spectrum.MethodsFirst of all, the corresponding relationship between caliper and thermal neutron capture γ spectroscopy was analyzed by Monte Carlo simulation based on the facts of 14 MeV deuterium-tritium (D-T) pulse neutron sources with a source distance of 30 cm for the uranium prompt fission neutron logging tube, two 3He gas detectors for neutron measurement, and one LaBr3(Ce) detector for γ spectrum acquisition. Well diameters of 110 mm, 130 mm and 160 mm were taken as simulation holes. Then, the variation of caliper was characterized by the hydrogen peak count rate of the captured γ spectrum, and the variation law of the hydrogen peak count rate was represented by a fitting function. Finally, the corresponding relationship between the hydrogen peak count rate and the caliper variation was obtained for the real-time correction of uranium mine caliper.ResultsSimulation results results shows that the change of well diameter can be characterized by the characteristic rate of hydrogen. The proposed method can reduce the influence of caliper change on the interpretation results of uranium fission prompt neutron logging.ConclusionsThis method has the ability to improve the reliability of uranium fission prompt neutron logging.

According to the study on the shape of plunge pool in the horizontal swirl spillway tunnel, the design scheme of a plunge pool with better energy dissipation effect is proposed. Based on the hydraulic physical model test, which includes atmospheric pressure and decompression tests, and combined with the different design scheme of a plunge pool, measurement results of fluctuating pressure. Main frequency and sidewall pressure are analysed. The results show that the inlet section of the plunge pool is connected by a gradual variable section which length of gradient segment 6m. The shape of the gradient section is a long round variable gate hole. To improve the side wall pressure, the inlet section is increasing from 6.0m to 14.0m. Finally, the proposed plunge pool has the advantages of simple design and convenient construction, and these studies provide reference and support for the design of hydropower dams in western China.

Gold nanoparticles supported on transition metal oxide catalysts have been prepared by deposition-precipitation. Their catalytic activity with or without Au doped has been tested for soot oxidation. Au improves the catalytic activity of transition metal oxide for the oxidation of soot particles. Under the catalysis of Au/Co3O4, the initial oxidation temperature of soot is 354 ℃.

The effects of the initial preheating perturbation on the dynamical behaviors of FGC wave propagation instability for low-velocity FGC in packed bed are studied numerically. The behaviors of the flame front inclination, break, and shrinking instabilities are always observed in experiments. Based on the experimental phenomena, an initial thermal perturbation model is numerically proposed as to predict the deformation behaviors of the flame front instabilities. The typical flame shapes are obtained depending on filtration velocity, equivalence ratio, and initial preheating temperature difference. It is demonstrated that the development of flame front inclination instability is proportional to the magnitude of initial preheating perturbation. At a lower equivalence ratio, the initial thermal perturbation of 300 K leads to the evolution of flame front break. Increasing filtration velocity leads to the appearance of flame front break, due to the intensification of the hydrodynamic instability. In addition, a perculiar instability of flame front shifting is also confirmed with the initial thermal perturbation of 400 K, which results in a fuel leakage of incomplete combustion.

Pedestrian-level wind conditions in residential areas are closely related to the quality of urban residents' daily life. In this paper, seven representative building layouts of urban residential areas were summarized from actual residential areas of Harbin, and wind tunnel experiments were carried out to study the pedestrian-level wind comfort in these residential areas. The assessments of pedestrian wind comfort are performed by combining the wind tunnel results and long-term local wind statistics. The results show that the hybrid-type and the enclosed-type layouts can provide better pedestrian wind comfort than parallel-type layouts, and the building heights of residential areas need to be controlled in cities of severe cold regions.