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Objective To explore the interaction between 1,25-hydroxyvitamin D3 [25-（OH）D3] and M-type phospholipase A2 receptor 1 （PLA2R1） gene polymorphism in the progression of idiopathic membranous nephropathy （IMN）. Methods A total of 101 hospitalized IMN patients from January 2019 to January 2023 were selected for this prospective study. They were assigned into two groups of recurrence and non-recurrence according to whether or not relapse occured within 6 months. Baseline profiles， 25-（OH）D3 level and PLA2R1 gene polymorphism were compared between two groups. Logistic regression was utilized for examining the influencing factors of IMN progression. And interaction coefficient γ and OR values were employed for analyzing the interaction effects of 25-（OH）D3 and PLA2R1 gene polymorphism on IMN progression. Results The level of uric acid was higher in recurrence group than that in non-recurrence group [（419.36 ± 25.44）μmol/L vs （366.20 ± 28.34）μmol/L] while 25-（OH）D3 level was lower than that in non-recurrence group [（33.60 ± 10.74）nmol/L vs （42.40 ± 9.56）nmol/L，P＜0.05]. The proportion of patients with AA genotype at rs4664308 locus was higher in recurrence group than that in non-recurrence group （69.44% vs 44.62%） while the proportions of patients with GA genotype （27.78% vs 43.08%） and GG genotype （2.78% vs 12.31%） were lower than those in non-recurrent group （P＜0.05）. Logistic regression analysis revealed that uric acid， 25-（OH）D3， GA and AA genotypes at rs4664308 were correlated with the progression of IMN （P＜0.05）； the risk of progression spiked by 4.233 folds for each unit of uric acid increase. For each unit reduction of 25-（OH）D3， the risk of disease progression increased by 0.581 fold. The risk of disease progression in GA and AA genotype rs4664308 patients was 3.253 and 4.054 folds higher than that in GG genotype ones. Interaction analysis showed that OR values of interaction between 25-（OH）D3 and PLA2R1 gene polymorphisms were ＜ product of OR values of two genes alone and the effects of two genes on the progression of IMN were in line with sub-multiplication model and interaction coefficient γ was ＞1. Abnormal 25-（OH）D3 had a positive interaction with PLA2R1 gene polymorphism （P＜0.05）. Conclusion 25-（OH）D3 and PLA2R1 gene polymorphisms are correlated with disease progression in IMN patients. And 25-（OH）D3 level has a positive interaction on the effect of PLA2R1 gene polymorphism， and combined detection may help to predict the risk of disease progression and provide decision-making support for personalized preventive interventions.

Blue sky often represents better air quality and lower air pollution. Using satellite aerosol optical depth (AOD) data of Beijing, Tianjin and Hebei Province from 2000 to 2023, combined with the blue-sky data observed at noon time in 2023, a blue-sky grade index is established based on satellite AOD, in which the monitoring index of blue-sky grade is the AOD at 550 nm less than 0.36, and that of deep blue-sky grade is the AOD at 550 nm less than 0.2.Spatial and temporal characteristics of blue-sky grade days in Beijing-Tianjin-Hebei Region from 2000 to 2023 are investigated. Results show that the multi-year average blue-sky days in Beijing, Tianjin, and Hebei are 144.2 d·a-1, 96.3 d·a-1, and 119.6 d·a-1, respectively, with the highest number of blue-sky days for Beijing, followed by Hebei and the lowest number is recorded in Tianjin. In terms of spatial distribution, the northern part of Hebei has the highest annual average of blue-sky days, while the southern part of Hebei has the lowest number of blue-sky days. The number of blue-sky days in Beijing-Tianjin-Hebei exhibits noticeable seasonal changes, with the highest number of blue-sky days in winter and autumn, followed by spring, and the lowest in summer.From 2001 to 2023, the average annual number of clear-sky days in Beijing, Tianjin, and Hebei takes on an increasing trend, with an increase of 18.1 d, 22.3 d and 16.3 d per decade, respectively. There is no significant trend change from 2001 to 2013. However, the annual average blue-sky days in Beijing-Tianjin-Hebei from 2013 to 2023 all show increasing trends, with increments of 26.9 d, 46.5 d, and 36.4 d per decade, respectively. The annual average blue-sky days and deep blue-sky days in Beijing-Tianjin-Hebei from 2013 to 2023 are higher than those in 2001-2013, with the annual average blue-sky days in Beijing, Tianjin, and Hebei of 153.5 d, 107.5 d, and 128.5 d, respectively, which are 17.5 d, 21.8 d, and 16.9 d higher than those in 2001-2013. It may be largely due to the implementation of regional air pollution prevention and control measures, which have led to a reduction in atmospheric particulate matter concentration since 2013.

[Objective] The study aims to explore the antibacterial activity and allelopathy of flavonoids from leaves of Eleutherococcus brachypus, and to provide the basis for the development of plant-derived antimicrobial agents and the application of their allelopathy in plant protection and agricultural production. [Methods] Leaf flavonoids was extracted by an ultrasonic-assisted method from E. brachypus leaves, then the antibacterial sphere, the minimum inhibitory concentration (MIC), the apoptosis rate, MDA content, ROS content, and the activity of antioxidant enzymes of epidermal cells from onion scaly leaves, as well as the inhibitory rate of the onion root and shoot growth were determined with different concentrations of leaf flavonoid extracts (100%, 50%, and 25%). [Results] (1) The yield of leaf flavonoids from E. brachypus was 42.3 mg/g. (2) At same concentration, the diameter of the inhibition zone was S. aureus > B. subtilis > Salmonella, respectively, and expanded with the increase in the extract concentrations with the same strain. The minimum inhibitory concentration of the three strains was also S. aureus < B. subtilis < Salmonella, respectively. (3) Each concentration of leaf flavonoids from E. brachypus induced apoptosis in the upper epidermal cells of Allium cepa. Meanwhile, as the concentration of flavonoid extracts increased, the apoptosis rate, MDA content, and H2O2 content were increased. POD activity and CAT activity were increased first and then decreased during the same time of treatment, which were higher in treatment groups than the control. (4) The growth of root and shoot of the onion scale leaves were inhibited under the treatment of flavonoids extracts, which was negatively correlated with the treatment dose. [Conclusion] The antibacterial effects of the leaf flavonoid extracts of E. brachypus on Gram-positive bacteria are better than that of Gram-negative bacteria, and the antibacterial effects are positively correlated with the concentration of flavonoid extracts. Moreover, all these changes suggest that the allelopathic mechanism of flavonoid extracts from E. brachypus may be due to the overproduction of ROS and the inhibition of antioxidant enzyme activity, which cause oxidative damage to membrane lipids and cell death.

ObjectiveTo investigate the pathogenic spectrum and molecular characteristics of infectious diarrhea among children in Putuo District of Shanghai from 2018 to 2023， and to provide scientific basis for the prevention and control of infectious diarrhea in children.MethodsFecal samples from the cases visited sentinel hospitals for children’s diarrheal disease in Putuo District， Shanghai， were collected from January 2018 to December 2023. A total of 11 species of bacteria were isolated and cultured， and 5 species of viruses were detected by real-time fluorescent polymerase chain reaction （PCR）. The molecular typing of some positive strains was analyzed by the standard pulsed-field gel electrophoresis （PFGE） method. The polymerase-capsid protein linkage region of some norovirus-positive samples was amplified by reverse transcription PCR， and was sequenced and analyzed by bioinformatics software. The Chi-square test and Fisher’s exact probability test were used to compare the pathogen-positive rates in 2018‒2019 and 2020‒2023.ResultsOf the 707 cases of children with infectious diarrhea， the total positive rate was 47.67%， with a single bacterial positivity rate of 16.27%， a single viral positivity rate of 22.63%， and a mixed positivity rate of 8.77%， respectively. The dominant pathogens were rotavirus （10.75%）， norovirus （10.33%）， enteropathogenic Escherichia coli （8.06%）， Salmonella （6.36%）， enteroaggregative Escherichia coli （5.52%）， and Campylobacter （5.23%）. Bacterial infections were predominant in summer and fall， and viral infections were predominant in winter and spring. The total positive rate decreased in 2020‒2023 compared with that of 2018‒2019 （χ2=5.753，P

Background The promotion of appropriate traditional Chinese medicine (TCM) techniques in primary care institutions is an important measure emphasizing the co-development of Chinese and western medicine, and enhancing the inheritance and development of TCM. Objective To analyze primary health workers'preferences for the use of appropriate TCM techniques, providing policy recommendations for the promotion and use of such techniques in primary healthcare institutions. Methods This questionnaire survey was conducted between July and August 2021. A discrete choice model with seven attributes and 18 choice sets obtained through the use of an efficient orthogonal design were used to develop the questionnaire used in the survey, and the questionnaire has three versions each version with evenly allocated six choice sets (including an opt-out option). Additionally, the three versions have a common general demographic part (sex, age, education level, professional title, etc.) and one common consistency test question. A randomized multistage stratified cluster sampling was used to select 319 health workers on duty on the survey day from a total of 23 primary healthcare institutions in three counties in eastern, central and western China (one county was extracted from each region), and each worker was required to complete one version of the questionnaire extracted sequentially by themselves. Two hundred and ninety-five cases who returned a questionnaire passing a consistency test were included for analysis, resulting in a response rate of 92.5%. Primary health workers' preferences for appropriate TCM techniques were analyzed using conditional Logit models and latent class models. Furthermore, the changes in utility of primary health workers due to attribute level changes were monetized using willingness to pay and presented accordingly. Results The conditional Logit analysis showed that medical insurance, the average duration of each operation with the TCM technique, the influence of operation with the TCM technique on income, work burden, the promotion of professional title, and patient healthcare cost, as well as effectiveness of the TCM technique were associated with primary health workers' preferences for the use of appropriate TCM techniques (P

In order to improve the axial compression bearing capacity of concrete filled steel tubular columns, steel fibers were added into self-compacting concrete.Through orthogonal test, the influence of 3 groups of steel fiber content on the strength of self-compacting concrete is studied, and the basis for the steel fiber content of concrete filled steel tube is provided.The axial compression tests of steel fiber reinforced concrete filled steel tubular columns and ordinary steel fiber reinforced concrete filled steel tubular columns were carried out to study the influence of steel fiber on the axial compression properties of self-compacting concrete filled steel tubular columns.Based on ABAQUS, 26 groups of concrete-filled steel tubular column models with different steel fiber content are established.After the correctness of the model is verified according to the field test results, the influence of six groups of steel fiber content on its axial compression performance is analyzed, and the calculation formula of the axial compression bearing capacity of concrete-filled steel tubular column with different steel fiber content is established.The results show that 2 % steel fiber has a significant contribution to the strength growth of self-compacting concrete, and can increase the axial compression bearing capacity of self-compacting concrete filled steel tubular columns by about 4 %.The calculation formula considering the increase of steel fiber content to the strength of concrete filled steel tube is proposed, which is in good agreement with the test results.

In this work, the effects of addition of different amounts (2%, 4% and 6%) of soy protein isolate (SPI), egg white protein (EWP) and whey protein isolate (WPI) on the structure of silver carp surimi myofibrillar protein (MP) and its ability to bind to fishy-odor compounds (hexanal, nonanal, and 1-octen-3-ol) were investigated. The results indicated that adding an appropriate amount of external proteins could promote the unfolding of MP, thus increasing its surface hydrophobicity, turbidity, particle size, and zeta-potential. Moreover, the exposed hydrophobic group enhanced the ability of MP to bind to hexanal and nonanal, and the exposed hydroxyl group enhanced the ability of MP to bind to 1-octen-3-ol. With increasing amount of added EWP and WPI, the capacity of MP to bind to 1-octen-3-ol increased due to the increased hydrophilic groups on the protein surface. In addition, addition of WPI could better enhance the capacity of MP to bind to the three fishy-odor compounds.

In order to solve the problem of floor heave control in deep soft rock roadway, based on the engineering background of the 18th floor track roadway in the south of the fourth level of Xing’an Mine, a new type of bottom heave control technology, that is combined inverted arch-floor pile. The numerical analysis of combined inverted arch-floor pile was carried out by ABAQUS software, and its bearing capacity and deformation were studied. Through the FLAC3D software, the floor heave control effect of the combined inverted arch-floor pile is analyzed, the bottom heave control mechanism of the combined inverted arch-floor pile is discussed, and the influence of the rise-span ratio on the floor heave control effect of the combined inverted arch-floor pile is revealed. The result shows that under the action of uniform load, the number and strength of connecting rods at the mid-span should be appropriately increased in the combined inverted arch. The length and strength of the embedded end should be appropriately increased. The bottom casing in the combined inverted arch -bottom pile is very important, and the strength of the bottom casing should be appropriately increased. The reasonable range of the rise-span ratio of the combined inverted arch-floor pile is 0.225-0.250.

ObjectiveTo investigate the impact of vinyl chloride monomer (VCM) alone or in combination with high-fat diet on gut microbe in mice. MethodsTwenty 6-week-old male specific pathogen-free C57BL/6J mice were divided into four groups: control, high-fat diet (40% of fat), VCM (static inhalation of 2 hours at dosage of 800 mg/m3, 5 times per week continuously for 13 weeks), and VCM plus high-fat diet. By the end of treatments, fecal samples were collected from the mice for 16S rDNA sequence analysis to examine alterations of the mice′s gut microbe. ResultsThe abundance and community structure of gut microbe changed in the mice with high-fat diet and VCM exposure. In terms of phylum, the ratio of Firmicutes to Bacteroidetes of the mice exposed to VCM and high-fat diet were higher than those of control mice. At genus level, the degree of gut microbes aggregation was different among the four groups. Alpha diversity analysis revealed that the observed gut species of the mice with high-fat diet were inferior to those of the mice of control and VCM plus high-fat diet group (both P < 0.05); the Shannon index for the mice with high-fat diet was significantly lower than that for the mice of other three groups (all P < 0.05). Beta diversity analysis indicated that there were differences in community composition of gut microbes among the four groups. ConclusionExposure to VCM and high-fat diet, alone or combined, could lead to gut microbial imbalance in mice and the combined exposure mainly affect the abundance of gut microbial genera.

The measurement of gas phase collision cross section (CCS) of ions can provide complementary structure information to those typically obtained from mass spectrometry or tandem mass spectrometry. Thus, the ion mobility spectrometry is typically coupled with a mass spectrometer to achieve the advantage after the combination. Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS) is characterized by its ultra high resolution and tandem mass spectrometry capabilities. Due to the collisions with neutral molecules, the image current caused by the cyclotron motion of ions in the analysis cell gradually decays under high vacuum condition. Based on this feature, the CCS of ions can be calculated by selecting an appropriate theoretical model and combining with the corresponding algorithm. This method can be directly applied to obtain the value of CCS of the selected ion through the analysis of high-resolution mass spectrometry data without increasing the cost of instrument hardware. With the development and promotion of FT-ICR MS instruments in recent years, such methods have developed rapidly in the past decade and have attracted extensive attention. There are three different ion-neutral collision models (Langevin collision model, hard-sphere collision model and energetic hard-sphere model) which have been applied to connect ion CCS and image current of FT-ICR MS instruments. Time-domain analysis, frequency-domain analysis and time-frequency analysis are three types of data analysis method used to measure ion CCS based on FT-ICR MS. Although the reliability and accuracy of the CCS data provided by such methods need to be further improved, it has been demonstrated its unique advantages in the dynamic CCS measurement and potentials in isomerization study. Such methods can be further combined with ion mobility technology to provide multi-dimensional ion structure information with the help of FT-ICR′s superior mass resolution and superior ion manipulation capabilities.

The situation of civil aircraft structure repair process may beyond the scope of the manual,a civil aircraft structure repair plan platform based on Browser/Service(B/S)is developed in this paper,which is aim to provide the relevant reference scheme of maintenance engineers in the formulation process of structure repair process beyond the scope of the manual. Firstly,the platform requirements are analyzed from the perspective of business process and platform function. Secondly,on the basis of technologies used in the platform development,the platform design is analyzed in detail from three aspects of platform architecture,database and platform function module. Finally,the main function modules of the platform are tested through the actual operation demonstration. The results show that the platform has friendly man-machine interface,good expansibility,simple and convenient operation,can realize the electronization of civil aircraft structure damage information and repair scheme,and automatically recommend several repair schemes stored in the database according to the damage information,which provides support for the maintenance engineering department to quickly formulate the repair scheme beyond the manual.

It is very important for the economic operation of civil aircraft to make reasonable procurement and configuration of aviation materials between multiterminals.The theoretical algorithm content formed by the research of aviation material prediction and configuration is relatively complex.In order to promote the effective application of these algorithm programs,based on the Java language,and the algorithm programs written in Matlab and Python are integrated,a multi language hybrid programming system platform for the prediction and configuration of civil aircraft is developed.Firstly,the support vector machine algorithm and marginal analysis algorithm integrated in the system platform are introdused,and the implementation of hybrid programming is described.Then,the details of the system platform design are expounded,and the implementation of hybrid programming and the conversion method of different types of programming language’s parameter are explained.Finally,the system platform functions are tested with the actual engineering data.The result shows that the platform’s human-machine interface is friendly and easy to operate,and it can better realize the functions of aviation material prediction and aviation material configuration,which can provide reference and ideas for the relevant theoretical algorithm to meet the engineering needs through platform technology.

The traditional Continuously Variable Transmission （CVT） dynamic control strategy takes the maximum engine power as the control target. As CVT efficiency varies greatly under different loads， the maximum engine power cannot guarantee the maximum driving power at the same time. For this， the matrix optimization algorithm is designed to calculate the CVT dynamic speed ratio under different pedal opening and vehicle speed with the maximum driving power as the target. A whole vehicle model is established by using GT-drive software， and the control strategies before and after optimization are simulated and compared. The result indicates that the optimized control strategy can improve the driving power and the maximum vehicle speed to different degrees under each pedal opening.

Objective To observe the curative effect of aprepitant on chemotherapy-induced nausea and vomiting(CINV) and hemoglobin level in gynecological malignancy patients. Methods A total of 85 gynecological malignancy patients in our hospital from July 2013 to June 2017 were divided into the aprepitant group and the control group, according to patients' anti-nausea drug usage.Both groups received chemotherapy and conventional symptomatic treatment; the aprepitant group was added with aprepitant.We observed nausea and vomiting, hemoglobin level and peripheral blood in two groups. Results The incidence of nausea and vomiting after chemotherapy was lower in the aprepitant group(P < 0.05), but there was no significant difference in the incidence of dizziness, headache or other adverse reactions between two groups (P > 0.05).The decrease of erythrocyte number after chemotherapy in the aprepitant group was slightly less than that in the control group(P > 0.05). Conclusion The aprepitant could not only effectively prevent the occurrence of chemotherapy-induced nausea and vomiting, improve patients' quality of life and treatment compliance, but also make patients eat early, which is conducive tothe formation of hemoglobin and reducing tumor burden and chemotherapy-induced anemia.

Unlike the normal recurrence quantification analysis（ RQA） which pay attention to the distribution of different kinds of lines such as diagonal lines,vertical lines and horizontal lines,a new perspective to study recurrence plot（ RP） is developed and the local detail spectrum（ LDS） will be proposed as one new RQA measure. This method pay more attention to the local details of the recurrence plot. The application of LDS in gear fault signal is studied in detail. The experiment proved the better performance of LDS in the field of gear fault diagnosis.

Label classification aims to select the most relevant subset of labels from a set of labels to tag an instance, which has become a hot issue in the field of artificial intelligence. Traditional multilabel learning methods mainly focus on identifying single-modal data, with limited research on mining high-order correlation between multi-modal data. To address the issue of insufficient representation of high-order correlations between multi-modal data in multi-label scenarios, this paper proposed a multimodal multi-label classification method based on hypergraphs. The hypergraph model is introduced to model the high-order correlations of multi-modal data, and the fusion of multi-modal features and hyperedge convolution operation are utilized to achieve the mining of multi-modal data relationships and feature recognition, thus improving the performance of multi-modal multi-label classification. Experiments were conducted on the movie genre classification task, and the proposed method was compared with traditional methods. The experimental results show that the proposed method outperforms the comparison methods in terms of accuracy, precision, and F1 score, demonstrating the effectiveness of the method. [ABSTRACT FROM AUTHOR]

Learning to index is the key to solving the problem of approximate nearest neighbor search in massive high-dimensional data. However, existing learning to index techniques are limited to individual partitions and rely on the construction of neighborhood graph. As the dimensionality and scale of data grow, indexing struggles to accurately judge boundary data of partitions, leading to increased construction time complexity and challenges in scalability. To address the above problems, a learn to index method based on partitioned hierarchical graphs, PBO-HNSW is proposed. The method redistributes partition boundary data and constructs distributed graph index structures in parallel. It effectively addresses the challenges faced by the approximate nearest neighbor search problem. Experimental results show that PBO-HNSW method is able to achieve millisecond index construction on millions of massive high-dimensional data. When the recall is 0.93, the construction time of the PBO-HNSW method is only 36.4% of baseline methods. [ABSTRACT FROM AUTHOR]

In order to solve the difficult problem of flame retardant modification of thin-walled polypropylene (PP), diethyl aluminum hypophosphite (ADP), polyphosphate, and NOR flame retardant (NOR116) were added into PP to prepare flame retardant thin-walled PP. The effects of three flame retardants in different proportions on the flame retardancy, thermal stability and optical properties of PP materials were studied, and the flame retardancy mechanism was explored. The results show that when the mass ratio of ADP: OL1001: NOR116 is 5:5:1.5 and the total amount of flame retardant is 11.5%, the thin-walled PP (0.5 mm) material can reach VTM-0 grade and LOI is 28.5%, which has good thermal stability and charring performance. The crystallinity of PP decreases after the introduction of flame retardant system. When the total amount of flame retardant is 11.5%, the apparent activation energy of PP increases to 105.5 kJ/mol, which indicates that the introduction of flame retardant system can significantly improve the thermal stability of PP and delay the degradation of materials. NOR116 has obvious synergistic effect in gas phase, and ADP/OL1001/NOR116 system has rapid carbon formation in condensed phase and free radical capture and dilution effect in gas phase. [ABSTRACT FROM AUTHOR]

【Objective】 The baffle plates in the forebay of lateral inlet pump stations are critical components to control water flow and optimize the performance of the pump station. We proposed a method to optimize their design. 【Method】 We used computational fluid dynamics (CFD) combined with the backpropagation neural network-genetic algorithm (BPNN-GA) to optimize the design parameters of the rectification baffle plates in the forebay. The optimization process used a comprehensive evaluation index, F, which calculated the fitness of the genetic algorithm based on the uniformity of the axial flow velocity distribution and the velocity-weighted average angle. The BPNN model was fine-tuned, with the comprehensive index F as the optimization objective, leading to the identification of optimal design parameters for the rectification baffle plates. 【Result】 The optimization results showed that the rectification baffle plates designed by the BPNN-GA algorithm significantly improved the flow pattern within the inlet channel. Notable improvements included increased uniformity in axial velocity distribution and a better velocity-weighted average angle. Additionally, the improved design also significantly reduced the vortex area within the forebay, with the comprehensive evaluation index F showing a 6.31 reduction. 【Conclusion】 The proposed BPNN-GA algorithm for optimizing the design parameters of the rectification baffle plates effectively ameliorated the undesirable flow conditions in the forebay. It provides a valuable method for improving the design of similar hydraulic structures.

Under natural lighting conditions, UAV (unmanned aerial vehicle) aerial images contain low-light images, which affect the accuracy of target detection, and detection tasks based on aerial images often have high real-time requirements. To address the above problems, a feature-level adaptive enhancement target detection algorithm for UAV aerial images is proposed. Firstly, an improved Laplace operator is fused with the IAT (illumination adaptive transformer) image enhancement network to enhance the edge features of the target and improve the target detection ability. Secondly, a two-branch structure is used to learn the normal image and the enhanced image in parallel, and the learnt features are fused in an adaptive selection manner to construct a BLENet (bad lighting enhancement net) feature-level adaptive enhancement network, which can adapt to the illumination and enhance the information of the image automatically. Then, the deformable convolutional FS-DC module based on frequency domain separation and the FS-C2F module with parameter sharing are designed so as to reduce the number of model parameters and computational redundancy while enhancing the ability of capturing high-frequency information. Finally, the regression loss function Wise-IoU is improved so that the model further focuses on the medium- and high-quality anchor frames, thus reducing the boundary regression loss and improving the localization accuracy. Experimental results on the publicly available dataset visDrone2023 show that compared with the baseline model, the final model improves the mAP@0.50 by 2.3 percentage points while keeping the FPS at 99 frames per second, which makes it suitable for UAV aerial photography real-time inspection and monitoring tasks under the environment of varying light in the open air.

BackgroundSextupoles are an important component of storage ring octonal unit in high energy synchrotron radiation sources. They require complex technological processes and precise center extraction. Therefore, it is necessary to find out the most reasonable calibration scheme for the mechanical center.PurposeThis study aims at the calibration scheme for the mechanical center extraction of high energy photon Ssurce (HEPS) sextupoles, and obtaining the corrected mechanical central coordinate system.MethodsThe method of directly measuring the reference plane of the sextupole was adopted for the mechanical center calibration of magnets. By rotating the conventional calibration coordinate system with a given pole seam deviation angle, the three polar seam surfaces were brought closer to the theoretical positions to decrease the main diagonal component of the sextupoles. The mechanical center calibrations were performed twice for each hexacode iron to further reduce the impact of the polar seam error.ResultsThe calibration results show that the calibration repeat accuracy is 0.005 mm for the sextupole. The standard deviation between the measured value and the design value of the pole seam spacing is 0.015 mm. Additionally, the standard deviation of the reference point before and after the rotation of the coordinate system is 0.09 mm, with a maximum rotation angle of 0.6 mrad.ConclusionsThe calibration scheme of this study can be used to improve the calibration accuracy and provide reference for the calibration of similar equipment. It ensures smooth installation of accelerator devices and is of significant importance for accelerator collimation measurements.

Now fault monitoring of hydraulic control outlet valve of centrifugal pump is still lacking in condition monitoring and fault diagnosis system of pumping station. Take a pumping station of a Yellow river diversion irrigation area as an example, the method of fault monitoring of hydraulic control outlet valve of centrifugal pump was proposed. Based on water hammer calculation the pressure head of pressure measuring point with time when operating pump was normal stop. Comparing with experiment result, the two were basically close. The pressure heads of pressure measuring point with time under maximum and minimum net head at certain closing law of hydraulic control valve when operating pump was normally shut down can be obtained by water hammer calculation and then sum of squares for the difference of pressure head under maximum and minimum net head at every moment in calculating period. The fault monitoring indicator ε of hydraulic control outlet valve of centrifugal pump can be obtained by correction. E can be obtained by the sum of squares for the difference of pressure head from water hammer calculation under maximum net head and measuring in operating of pump. If E is greater than ε, there may be a fault for hydraulic control outlet valve of centrifugal pump. After practical engineering application, the method of fault monitoring of hydraulic control outlet valve of centrifugal pump is effective. [ABSTRACT FROM AUTHOR]

The Russia–Ukraine conflict has imposed a profound impact on the global energy market and geopolitics, and also brings about a major challenge to China's energy security. In the winter of 2022, it is inevitable for Europe to have stronger access to global LNG, and its price will be at high price. Thus, the LNG import of China will be decreased, thus bringing severe challenges to supply guarantee in the winter, especially during the peak months of this winter. Due to the reduction of Russian oil and gas imports by Europe, a considerable volume of the working gas of Russia's gas storage(1 100×108 m3) becomes useless. Therefore, the feasibility of utilizing the working gas of Russia's gas storage for peak sheaving of China's gas supply market was discussed under the condition of obviously insufficient capacity of China's gas storage. Hence, three approaches were proposed, including(1) gas exchanging by Central Asia-China Gas Pipeline,(2) LNG interchange in Russia, and(3) increasing gas transportation capacity of China–Russia Eastern Gas Pipeline to realize operation at full load. Meanwhile,requirement was put forward for Russia to supply gas supply with the quality in strict accordance with the contract. Generally,the relevant recommendations could provide reference for the supply guarantee in the winter of 2022.

BackgroundCompared with 2D+1D adjustment, three dimensional adjustment has a more rigorous theoretical basis. However, when the unconstrained three dimensional adjustment is applied to the observation values processing of the accelerator alignment control network, serious error accumulation will occur and resulting in obvious distortion of the results.PurposeThis study aims to expound the ways and characteristics of three dimensional adjustment error accumulation for accelerator alignment control network.MethodsFirstly, based on the layout of accelerator alignment control network and the moving station measurement method of laser tracker, the three dimensional adjustment mathematical model was analyzed, and the least-squares collocation theory was used to clearly explain the error propagation. Secondly, the characters of laser tracker measurement accuracy, station positioning and orientation accuracy and single station measurement error propagation were studied by analyzing the laser tracker 3D coordinate measurement model, measurement point error model and simulation measurement experiments. Finally, adjustment calculation of the linac control network was verified by simulation measurement, and two error accumulation suppression methods were tested.ResultsThe source and propagation mode of error accumulation are explained theoretically, and verified by simulation calculation, so are the serious error accumulation of elevation and lateral errors in three dimensional adjustment of control network in accelerator.ConclusionsProviding high-precision point coordinate constraint for three dimensional adjustment can effectively suppress error accumulation, and providing high-precision orientation constraint for station coordinate system can also achieve the effect of suppressing error accumulation.

To satisfy the requirement of the polarized light celestial positioning for the high precise information of solar spatial position, a new detecting method for the position of the sun by a new three channel polarization imaging system is proposed based on atmospheric polarization mode. The method is used to calculate the position of the sun by using the polarization information of the atmospheric polarization mode. Compared with the traditional method based on spot detection, the current one is an indirect calculation method to calculate the sun position by using the polarized light characters. This method has advantages such as wide field of view and high precision. The system consists of industrial CMOS lens, polarizer and fish-eye lens. We build up an experimental platform to verify the method based on theory. The experiment shows that the measurement accuracy is 0.02°. Therefore, this method not only meets the requirement of detection, but also provides a new solution for the field of the sun position detection. [ABSTRACT FROM AUTHOR]

An eight-node solid-shell element, a nonlinear distributed electric potential element and an isoparametric thermal element have been used to formulate the coupled thermo-piezoelectric-mechanical model of plates and shells based on the Hellinger-Reissne variational principle. Hybrid stress and assumed natural strain are adopted to immune to shear, membrane, trapezoidal, thickness lockings. According to the present model, the static and dynamic problems of overall and distributed piezoelectric sensor/actuator are calculated. The numerical results show that the proposed model has well effective and accurate. The effect of environmental factors such as electric, thermal load can be validated by the related examples in which thermal load only effects mechanical load and electric load effects both mechanical load and stiffness. Then the active control of piezothermoelastic systems is obtained by the method of negative velocity feedback. Further, modify feedback control method with displacement feedback added is provided in order to eliminate the gap caused by thermal load. [ABSTRACT FROM AUTHOR]

The free-piston engine has an advantage of changeable piston motion trajectory because of its lack of mechanical constraint. The motion law of a four-stroke ignited free-piston engine was studied in order to improve the efficiency of the system. Based on analyzing the working principle of the system and setting boundary constraints and path constraints of the system, an optimized model of the piston motion was established. The working cycle of the free-piston engine was composed of intake, compression, combustion, expansion and exhaust phases. Based on the characteristics of separate phase of the piston motion, a trajectory optimal method called gauss pseudospectral method (GPM) was used to separate the states and control variables. In this method, the piston position, the piston velocity, the in-cylinder gas pressure and the in-cylinder gas temperature were set as the state variables and the electromagnetic forces were set as the control variables. Then the optimal problem of piston motion was discretized to nonlinear programming problem. Then the nonlinear programming problem was solved by the sequential quadratic programming method (SQP). Furthermore, the parameters of the 462 engines were taken as the computing parameters. The fuel used in the simulation was gasoline. The simulation results showed that by adjusting the separate electromagnetic force and optimizing the piston position and velocity curves, the output work increased while the heat-transfer loss reduced with the rapid piston motion. It indicated that the efficiency reached as high as 45.3% in the simulation. During the compression process, the applied time of the optimized electromagnetic force was delayed compared with the original. And the time spent in the optimized compression process was shorter than the original. During the early expansion process, the optimized amplitude of the electromagnetic force was bigger than the original, which made the in-cylinder combustion close to constant volume combustion and the gas pressure and temperature increase quickly. During the middle expansion process, the electromagnetic force was not applied, which made the piston move fast and avoid more losses of heat transfer under the condition of high temperature and high pressure. During the late expansion process, the big electromagnetic force was applied in order to meet the target expansion length. Then comparison experiments of different piston trajectories were studied under the natural aspirate. The intake air pressure was 0.1 MPa, the temperature was 303 K and the excess air coefficient was 1.05. The results were derived from repeat experiments, which validated that the optimal method was feasible and valid. The in-cylinder peak pressure had a notable increase when the electromagnetic forces were applied by separate phase. The output electrical efficiency reached 31.2% and the system performance was remarkably improved. The output electric power had a small increase, because the cycle period was extended. As a result, the proposed optimization method of the piston motion law has an important significance for the system development. [ABSTRACT FROM AUTHOR]

The problem of shape control of curved shell structures with the least piezoelectric actuators in the most reasonable layout at optimal multi-point voltages was addressed. First, a solid shell element for shell structures was constructed with the HS-ANS method, to overcome shear locking, trapezoidal locking and thickness locking. Second, the layout of actuators was designed through the GA combinatorial optimization and the input actuator voltage was decided with the GA numerical optimization. The general computation processes were also built respectively. The following examples show the effectiveness of the proposed solid shell element and optimization method to control deformation of the curved shell structures. [ABSTRACT FROM AUTHOR]

In order to improve the calibration precision of 6DOF parallel mechanism, a calibration method based on external coordinate measurement is presented. The position and attitude informations of the parallel mechanism are acquired using common measuring devices and the residual equations with uniform measure are constructed. These equations can ensure the identifiability of each geometry parameter's, so no special auxiliary calibration equipments or redundant sensors are required. From the residual equations, the estimated values of geometry parameters are obtained by optimization method, and the ideal parameters are replaced by them for the parallel mechanism inverse kinematics calculation of to realize the error compensation. The simulation results show that this method can decrease the effect of measure noise, and the kinematics accuracy after calibration can reach the same order of magnitude as measurement noise since the errors of parallel mechanism's are not usually cumulated. The calibration accuracy is improved more than 5 times after error compensation by using the method. [ABSTRACT FROM AUTHOR]

To solve the configuration identification problem of mobile 6-DOF parallel mechanisms, the absolute coordinates of an arbitrary measuring point were measured under various configuration conditions, and a system of kinematics equations was built and solved optimally to identify the configuration parameters of a parallel mechanism at an unknown location and compute the coordinates of the measuring point. The adjustment value of each actuator can be obtained according to the target' coordinates of measuring point. Consequently the motion control of parallel mechanism can be performed. The redundant equation's were solved by using Trust-Region Dogleg algorithm, and the validity of this method was confirmed by experiment. The simulation and experiment show that the identification accuracy of measuring point is higher than that of parallel mechanism location. When the movement error of the parallel mechanism is no more than 0.02mm, its positioning error in the absolute coordinate system can be limited within 0.3mm using this method. [ABSTRACT FROM AUTHOR]

According to the actual load suffered by a servo mechanism in a large launch vehicle, a comprehensive load simulation system was presented, which could simulate the inertia, elastic, friction and constant loads. The inertia load, elastic load and flexible assembling base of servo mechanism were simulated by the mechanical structures, and the friction load and constant load were simulated using a hydraulic system. A complete mathematical model was constructed by modeling the servo mechanism, its flexible structure and the loading hydraulic system. It is shown that this system can reproduce the load characteristics of the servo mechanism in actual situation, and the redundant force of the loading system is suppressed effectively. A load simulation system was developed for simulation of the loads and resonant characteristics, which provides the necessary fundamental facilities for ground test and further research of servo mechanisms. [ABSTRACT FROM AUTHOR]

This paper gave the definition and constructing method of visual cryptography which can examine a cheater from the (k,n) threshold, and proved its security. It will result in failure when there exists a cheater who provides a pseudo share shadow, and the cheater will be found by the method. Just as the common visual cryptography share schemes, every participant keeps only a shared picture without extra in formation, when examining the cheater, the only operation is to splice the different k films of shared picture, which reflects the convenient principle of visual cryptography. [ABSTRACT FROM AUTHOR]

Using integer programming, this paper provided a new design method which uses (κ, n)-threshold scheme to realize any access structure. And this method has the following virtues. It uses a unique (κ, n)-threshold scheme to share the secret, and each participant has a subset of the subsecrets set. The design of the secret sharing scheme is independent on the (κ, n)-threshold scheme being used, it can use any (κ, n)-threshold scheme to realize an access structure. This method can realize any access structure without the limits on the access structure to be realized (such as the access structure must be a graph). For any given access structure P, the (average) information rate of the secret sharing scheme designed by this method is the biggist among all the (average) information rates of the secret sharing schemes which can use a unique (κ, n)-threshold scheme to realize P. [ABSTRACT FROM AUTHOR]

Rooting in the basic principles of set theory and geometry, this paper proposed a vector-based algorithm. The algorithm firstly discerned three types of topological relations between polygons, i. e. intersectional, contained, separated. If the two polygons were separated or contained, then it could easily get the difference of them; otherwise, it obtained the difference using the parallel line scanning method. The proposed algorithm can be used for computing the differences of two arbitrary polygons, including two polygons with multiply embedded holes (polygons), which is of great useful in computer-aided design, geographic information systems and cartography. [ABSTRACT FROM AUTHOR]

Diterpenoids are terpenoids containing four isoprene units with a total of 20 carbon atoms. They are derived from geranyl pyrophosphate, including acyclic diterpenes, monocyclic diterpenes, dicyclic diterpenes, tricyclic diterpenes, and tetracyclic diterpenes. These compounds are widely found in plants, insects, fungi and marine organisms, and are important bioactive substances in plant extracts. Diterpenoids have a variety of biological activities due to their structural diversity. Particularly, their outstanding antioxidant and antibacterial activities make them widely applied in meat preservation. In this article, the chemical and structural characteristics, biological activities and sources of diterpenoids are reviewed, and recent advances in the application of diterpenoids in the preservative of meat are summarized, aiming to provide a reference for the theoretical research and commercial application of diterpenoids in meat products.

Background Regulatory B-lymphocytes (Breg) are a group of cells with negative immunoregulatory effect, which have been detected of abnormal expression in the researches of various autoimmune diseases. Neuromyelitis optica spectrum disorders (NMOSD) belong to the category of autoimmune diseases, there are few studies on the expression and significance of Breg in the peripheral blood of patients with NMOSD. Objective To explore the expression and significance of Breg in peripheral blood of patients with NMOSD. Methods A total of 55 patients with NMOSD admitted to the Department of Neurology of the First Affiliated Hospital of Xinjiang Medical University from June 2019 to December 2021 were selected as the NMOSD group, and 50 healthy volunteers in the same period were selected as the control group. The expression of CD19+CD24hiCD38hi Breg and CD19+CD24hiCD27+ Breg in peripheral blood of patients in the two groups was detected using flow cytometry, the levels of interleukin 10 (IL-10), interleukin 35 (IL-35) and transforming growth factor β1 (TGF-β1) in the serum of patients in the two groups were compared and measured by enzyme-linked immunosorbent assay (ELISA) . Results The proportions of CD19+CD24hiCD38hi Breg and CD19+CD24hiCD27+ Breg cell phenotypes were lower in patients in the NMOSD group than in the control group (t=6.235, 12.131, P

Composite materials have been widely applied to the structure of high-speed flight vehicles due to their excellent performance. In hypersonic flight, the buckling and nonlinear flutter will occur in the composite panel on account of the combined action of unsteady aerodynamic load and thermal effect. In this paper, the nonlinear finite element model of the composite thin-walled structure considering thermal effect is established, and combined with the second-order loose coupling algorithm of dynamic-structure, the nonlinear aeroelastic response of composite panels at Ma∞=5 is analyzed. The influence of the direction of composite layer and tempera-ture load on the flutter characteristics of the panel is discussed. The results show that the flutter of the panel is affected by temperature load, layer direction and free stream dynamic pressure. The flutter critical dynamic pressure of the angle-ply panel is higher than that of the cross-ply panel (the increment is more than 55%). With the increase of temperature, the flutter pressure of the panels will decrease, and the maximum reduction is about 80%. While thermal buckling occurs, the flutter dynamic pressure will increase slowly. When the temperature exceeds the critical buckling temperature of the structure, the panel will have static buckling positions under subcritical conditions, and the buckling equilibrium position changes with different dynamic pressures.

In order to study the effect of silicification on low temperature oxidation characteristics of coal, scanning electron microscopy(SEM) was used to observe the difference of pore structure between silicified coal and non-silicified coal; the temperature programmed test system of spontaneous combustion of coal was used to test the characteristics of low temperature oxidation of two coal samples at different temperatures and the variation rule of indicator gas. On this basis, the oxygen consumption rate at different temperatures in the process of low temperature oxidation was analyzed. The results show that silicification enlarges the pores and increases the specific surface area of coal, on the one hand, it is beneficial to the occurrence of gas in coal, on the other hand, the composite reaction between coal and oxygen is more sufficient, and the silicified coal is easier to oxidize and spontaneous combustion; the volume fraction of the marker gas generated in the oxidation process of silicified coal is always higher than that of non-silicified coal, and when the temperature rises to 110 ℃, the difference in the volume fraction of the gas products of the two coal samples gradually becomes larger, which may be because silicification causes physical and chemical changes in coal body and its molecular structure, leading to oxidation cracking of silicified coal more easily; the rate of oxygen consumption and CO formation of silicified coal is always higher than that of non-silicified coal, indicating that silicification enhances the low temperature oxidation characteristics of coal.

BACKGROUND There are large amounts of copper-lead-zinc polymetallic sulfide ore resources in Yunnan Province, China, but the efficient separation of these resources remains a major problem. OBJECTIVES To improve the separation efficiency of valuable minerals in mixed concentrates. METHODS In this study, the major elemental content, phase composition, mineral composition, particle size characteristics, and monomer liberation degree of a mixed concentrate were analyzed using a variety of modern detection methods such as chemical analysis, X-ray diffraction, and mineral liberation analysis (MLA). RESULTS The results showed that the mixed concentrate had fine particles, and some minerals occurred as intergrowths or inclusions. The monomer liberation degree of the target minerals chalcopyrite, galena, and sphalerite was medium to low, ranging from 69.28% to 70.56%. It was preliminarily predicted that the theoretical separation efficiencies of copper, lead, and zinc in the mixed concentrate were 71.63%, 62.97% and 72.72%, respectively. CONCLUSIONS Improving the grinding fineness of mixed concentrates to promote the full liberation of metal minerals is a key way to improve the separation efficiency of copper, lead, and zinc minerals.

According to the oscillating flow in servo-controlled hydraulic piplines, the actual movement of the transient transition flow was considered. The momentum change of the fluid was analysised in the transient process based on considering its micro-compression, and an improved fluid dynamic model of pipeline was proposed. Based on the one-dimensional fluid transient theory, the analytical model of fluid transients in hydraulic piplines was carried out by the characteristic method and the finite difference method. The correctness of the simulation was approved by the comparison of calculation data with experiment data. The results show that these models give more reasonable descriptions for water hammer and flow oscillation during servo valve starting process and can provide guidance for designs and experiments of the hydraulic pipe system. [ABSTRACT FROM AUTHOR]

This course covers commonly used methods in laboratory of clinical biochemistry. The teaching plan reported here is aiming for encourage students to learn the technology and methodology based on clinical needs. So the teaching plan is characterized by combination of clinical information and pathogenesis of illness with biochemical results and thus to support students' learning in an active pathway. An example is calcium concentration in circulation as a parameter to support clinical diagnosis of various illnesses.

Convolutional neural network based network traffic classification scheme suffers many disadvantages such as the complex structure designing, gradient declines or even explodes, the deterioration of prediction accuracy, and etc. A residual network based improved traffic classification algorithm is proposed. The convolution layer and pooling layer in the traditional convolutional neural network are replaced by the residual network layer, which can alleviate the problem that the traditional convolution network is too deep to train effectively. The data feature information learned by the proposed algorithm in the training stage is more comprehensive, and the trained model can also be more accurate. Simulation results show that the improved algorithm has higher accuracy than the traditional neural network, which can be improved from 92.05%to 96.18%.

The difference between sleep and wakefulness is critical for human health. Sleep takes up one third of our lives and remains one of the most mysterious conditions; it plays an important role in memory consolidation and health restoration. Distinct neural behaviors take place under awake and asleep conditions, according to neuroimaging studies. While disordered transitions between wakefulness and sleep accompany brain disease, further investigation of their specific characteristics is required. In this study, the difference is objectively quantified by means of network controllability. We propose a new pipeline using a public intracranial stereo-electroencephalography (stereo-EEG) dataset to unravel differences in the two conditions in terms of system neuroscience. Because intracranial stereo-EEG records neural oscillations covering large-scale cerebral areas, it offers the highest temporal resolution for recording neural behaviors. After EEG preprocessing, the EEG signals are band-passed into sub-slow (0.1‍-‍1 Hz), delta (1‍-‍4 Hz), theta (4‍-‍8 Hz), alpha (8‍-‍13 Hz), beta (13‍-‍30 Hz), and gamma (30‍-‍45 Hz) band oscillations. Then, dynamic functional connectivity is extracted from time-windowed EEG neural oscillations through phase-locking value (PLV) and non-overlapping sliding time windows. Next, average and modal network controllability are implemented on these time-varying brain networks. Based on this preliminary study, it appears that significant differences exist in the dorsolateral frontal-parietal network (FPN), salience network (SN), and default-mode network (DMN). The combination of network controllability and dynamic functional networks offers new insight for characterizing distinctions between awake and asleep stages in the brain. In other words, network controllability captures the underlying brain dynamics under both awake and asleep conditions.

Hypertension is the primary disease that endangers human health. A convenient and accurate blood pressure measurement method can help to prevent the hypertension. This paper proposed a continuous blood pressure measurement method based on facial video signal. Firstly, color distortion filtering and independent component analysis were used to extract the video pulse wave of the region of interest in the facial video signal, and the multi-dimensional feature extraction of the pulse wave was preformed based on the time-frequency domain and physiological principles; Secondly, an integrated feature selection method was designed to extract the universal optimal feature subset; After that, we compared the single person blood pressure measurement models established by Elman neural network based on particle swarm optimization, support vector machine (SVM) and deep belief network; Finally, we used SVM algorithm to build a general blood pressure prediction model, which was compared and evaluated with the real blood pressure value. The experimental results showed that the blood pressure measurement results based on facial video were in good agreement with the standard blood pressure values. Comparing the estimated blood pressure from the video with standard blood pressure value, the mean absolute error (MAE) of systolic blood pressure was 4.9 mm Hg with a standard deviation (STD) of 5.9 mm Hg, and the MAE of diastolic blood pressure was 4.6 mm Hg with a STD of 5.0 mm Hg, which met the AAMI standards. The non-contact blood pressure measurement method based on video stream proposed in this paper can be used for blood pressure measurement.