Search

Due to its advantages of good toughness, corrosion resistance, low cost and constructability, etc., polyethylene (PE) pipeline is widely used in natural gas transportation. Because of the characteristics of PE pipeline, the material aging becomes a problem while using.The method for effectively and efficiently evaluating the aging performance of PE pipes in service has been highly concerned in the industry. There are differences in its aging condition due to differences in pipe diameter and material. It is found that the antioxidant capacity of PE pipes of the same PE material under the same SDR conditions increases with increasing pipe diameter as influenced by the wall thickness of the pipe. There are obvious differences in the antioxidant performance of PE pipes made from different materials; under the experimental conditions of this paper, the antioxidant performance of PE100 is significantly better than that of PE80.

CO2 geological storage is one of the important means to reduce carbon emission and greenhouse effect, and it is an emerging field of earth science research. The selection of the injection rate has an important impact on the CO2 storage capacity, and it is limited by the injection time and construction conditions, thus the selection of the injection rate is a complex optimization problem. In this paper, the optimal injection site calculated based on dynamic planning is used for injection simulation, based on which the carbon sequestration injection rate optimization problem is transformed into a differential evolution problem, and the problem is optimized by different differential methods. For the Utsira block in the Sleipner project in Norway. On this basis, the effect of injection rate on storage capacity and leakage is researched, and numerical simulations under different injection rates are designed. Thus, it provides theoretical guidance for the selection of injection rate in CO2 geological storage.

Global warming and rapid urbanization are changing the livability of cities. The eco-livability (EL) in Jiading, a newly emerging urban sub-center in the northwestern part of Shanghai megacity, is assessed from a climatic perspective, by composing an EL index consisting of meteorological hazards, human comfort, vegetation ecology, and air quality, based on multi-source observations. The results show that the EL in Jiading has improved with the restoration of green spaces and the reduction of air pollution. However, with the rising risk of weather extremes (e.g., heat waves, rainstorms) brought by the warming world, the EL in Jiading is being undermined. We should take preventive measures to improve our ability to resist climate risks.

The paper provides a solution to the task of implementing student’s character building activities as a component of the main educational program of higher education in a technical university through the common universal competences formation, the educational process is considered as a single focused process of education and training in the interests of a person, family, society and the state, where education is an activity aimed at personal development, creating conditions for self-determination and socialization of the student.

To solve the problem that the duty cycle of HPRF PD radar is not easy to use the general tow-and-pull jamming, a method of partial pulse remained jamming is proposed. Taking the transmitting signal of PD radar acquired by DRFM as an example, the jamming effect of the signal is simulated and analyzed. The results show that the jamming signal is modulated by the radar signal acquired by DRFM, the jamming signal generated has a strong correlation with the target Echo Signal, and it can effectively jam the HPRF PD radar with less power, which proves the effectiveness of the method.

Dynamic image, usually defined as motion graphics or dynamic graphics, is a kind of image art based on art design and computer science. In a broad sense, dynamic image is a discipline that integrates animation, film, and graphic design. Its expression content is more refined and straightforward than animated movies. It is more comprehensive than graphic design in conveying information. There are more types of dynamic images in the new media era. There are virtual reality technologies that rely on computer science and interactivity, and there are self-media on the Internet. Together with traditional media, they have more and more impact on the public's cognition. The interdisciplinary dynamic image is a visual language based on the dynamic image and interdisciplinary boundaries. It is main feature is to use dynamic images to express the main content of something, event or thought, a moving image made for the purpose of improving the public’s understanding of the corresponding thing, In the interdisciplinary dynamic images, the concreteness and narrative nature of the dynamic images are weakened, and the non-representation and scientific are more emphasized.

In order to achieve the best purification effect of PM2.5 at different personnel positions, it is necessary to study the PM2.5 purification time at different personnel positions in the room when the influence factors change, and establish a prediction model of the purification time.In this paper, air purifier and room models were established for simulation research. Purification time of air purifier at different locations in the room was taken as regression data, and multiple linear regression method was adopted to obtain the relationship between each impact factor and PM2.5 purification time, and a prediction model of PM2.5 purification time at different personnel locations in the room was proposed.The results of this study provide a theoretical basis for putting forward the whole intelligent scheme of air purifier.

The short-term probabilistic prediction of wind power has the characteristics of spatial dependence and time-series dependence. Considering the two characteristics at the same time can improve the prediction level. In this paper, a probabilistic short-term wind power prediction model considering the temporal and spatial dependence of prediction error is proposed. Considering the coupling relationship between the two properties, the NWP(Numerical Weather Prediction) wind speed point prediction error in the historical period is hierarchical clustering, and the empirical distribution model is used to fit the probability distribution of the error under different wind conditions; the cumulative empirical distribution probability value corresponding to the NWP wind speed at the time to be predicted is bootstrap sampling; under the given confidence level, the possible wind speed at each time point to be predicted in the short term is calculated The power fluctuation range of the generator. The test results show that this method can ensure the statistical significance and fitting stability of the sub sample set at the same time, and improve the classification accuracy of the days to be predicted. Compared with considering a single property, the result of probability prediction performs better on multiple evaluation indexes.

The healthy development of urban elements would be important to sustainable urban development, especially the elements of water resources. This paper discusses the key points and methods of water elements development and protection in urban design for Healthy-city, taking the design of China Ceramic Valley in Liling as an example. Based on the analysis of hydrological and geographic data, it establishes the network structure of the river system, summarizes systematic measures for the guidance and control of sponge cities, puts forward the optimization and control methods of waterfront spatial form and compiles quantitative and elastic space guidelines. The results show that the whole-scale and systematic urban design is a necessary step of urban water resources protection and utilization. It provides practical experience and process reference for urban health and sustainable development.

Efficiency and mechanism of nitrogen removals by ecological concrete-based ecological systems (ECBESs) were investigated in this study. Results show that ECBES performed well on denitrification. Ecological concrete as matrix of the ecological was positive for nitrogen removing according to that the experimental ECBESs achieved a greater TN removal compared to the control system. This result was possibly attributable to a higher biomass and increased bacteria diversity in ECBESs, since ecological concrete could be a carrier of microorganism. Vegetation could further improve TN removals. Acorus calamus L. - ECBES, Ipomoea aquatica Forsk - ECBESs, Oenanthe javanica (Bl.) DC. - ECBES and Zizania aquatica - ECBES achieved an average TN removal of 67.87%, 81.93%, 76.18%, 66.22%, respectively, in a test cycle. Nitrogen transformation in the ECBESs indicated the occurrence of ammonification, nitrification and denitrification. Moreover, bacteria related to nitrogen transformation was identified from the bio-film immobilized on the ecological concrete.

Muscle synergy is an important approach to evaluate motor function for patients with neurological diseases. Nonnegative matrix factorization (NMF) is the most widely used muscle synergy extraction method from electromyography (EMG) data. However, NMF usually falls into local optimum and is susceptible to noise, which significantly limit the promotion of muscle synergy. In this paper, a reliable synergy extraction method based on multivariate curve resolution-alternating least squares (MCRALS) was put forward. Its performance was compared with NMF through analyzing the EMG data of upper limb motor. The repeatability and intra-subject consistency were used to evaluate the two methods. As a result, MCR-ALS provided unique resolution result and better repeatability and consistency in contrast to NMF. Thus, the results of this study are of significance for the expansion and application of muscle synergy in medicine.

Sentinel-1A/B satellites operating in wave mode provide ocean winds dataset on a continuous and global basis. In this study, wind speeds derived from Sentinel-1A/B wave mode imagery from November 2018 to October 2020 are evaluated against HSCAT scatterometer aboard Chinese satellite HY-2B. Here, due to the close equatorial crossing times between Sentinel-1 and HY-2B, the spatio-temporal criteria of 50 km and 30 min yield large amount match-ups. Comparison results show a good agreement between wind speeds derived from the two types of radars: synthetic aperture radar and scatterometer. Impact of the presence of pure swell on the evaluation results is also discussed.

Seawater pH standard material is determined by potentiometric methods with hydrogen electrode silver / silver chloride electrode in non-liquid junction cell. As a standard material, uncertainty is an important quality parameter. The sources of the uncertainty of determination methods mainly include measurement repeatability and temperature, atmospheric pressure, electrode potential, chloride concentration and so on. According to the experimental data, the expanded uncertainty of the method is 0.004. Finally, through in-depth analysis of the influence weight of each component, it is found that the quality control of the standard electrode potential, measurement repeatability and chloride ion concentration of the electrode in the ion system is the key to ensure the accuracy of the setting value, which provides a reliable guarantee for the replication of reference materials.

In this paper, based on the auto disturbance rejection control technology, the electromechanical servo system is used as the control actuator, and the thrust vector control of the solid rocket motor nozzle with typical nonlinear friction characteristics is studied and analyzed. In this paper, the realization of the classical PID algorithm and the lack of dynamic performance are analyzed, and then the compensation algorithm based on the auto disturbance rejection control technology is added. The algorithm compensates for the phase lag of the system due to the nonlinear friction characteristics. As a result, the frequency characteristics of the system have been significantly improved.

The scarcity of water and increasing water pollution are the pressing challenge human being facing. Recovering water and valuable heavy metals is highly desired for treating heavy metal containing wastewater. We proposed a novel hydrate-based process to treat Ni2+ containing wastewater. The water recovery, Ni2+ enrichment factor, desalination efficiency were studied using this cyclopentane hydrate-based method. A water recovery of 43% can be obtained with a desalination efficiency of round 88% and an enrichment factor of 1.6. The desalination efficiency and the quality of the as-made water via the hydrate-based process can be further improved to above 99% via three-stage hydrate reaction. The proposed hydrate-based water treatment process may find wide applications in waste water treatment and heavy metal recycling.

Tourism index is a "barometer" to reflect the overall development level of tourism. The tourism index compiled by historical data can not reflect the real situation accurately with the increasing influence of network events on tourism In the Internet era. This study collects time series data of tourism network search by Baidu index tool and uses data mining method and principal component analysis method to detect and standardize the stability of the data. The spss system and the weighted analysis method are used to construct the tourism network index model. Finally, the model detection is carried out by comparing the actual tourism data in Sanya. This study is an important supplement to the existing tourism index.

Establish the piston ring-cylinder liner frictional model using the software of GT-Suite combine both of the frictional condition and lubrication, analyze and compute the thickness of oil film between piston ring and cylinder liner, the distribution of oil stress, and the force and power of the friction in rated condition. Then, mainly analyze the thickness of oil film and power of friction at the first piston ring under different temperatures of lubrication oil and different speeds. The results indicate that: The lubrication effect at first piston ring is poor, and the consumption of frictional power is high. The frictional power is significantly reduced with the oil temperature increases. However, the thickness of the oil film will decrease with the oil temperature increases, which is bad to the lubricational condition. Considering both of the lubrication condition and the frictional power, the frictional characteristics are better when the oil temperature is maintained at 80-90°C. With the increase of rotational speed, the oil film thickness and frictional power increase, but comparing with the influence on the frictional power, the change of rotational speed has less influence on the oil film.

In order to improve the mechanical properties of the polymer materials, three kinds of samples with the same size were manufactured by the 3D printing equipment. And the materials were polycarbonate, ABS and polypropylene, respectively. After -190°C+8h cryogenic treatment, the mechanical properties such as wear resistance and hardness were tested and the functional groups and internal molecule chain changes were observed by Fourier transform infrard spectrometer. The results showed that the mechanical properties of polymer materials can be improved effectively after the cryogenic treatment. Compared with the untreated samples, the hardness of the PC, ABS and PP samples increased by 27.6%, 10.8% and 20.3% respectively. Among the three materials, the wear resistance of ABS material was improved obviously.

The online store credit rating is a reflection of the seller's integrity and the quality of the product. The level of the credit rating directly affects the buyer's desire to purchase. Two important factors affecting the credit rating are data and models. The innovation of this research is that the collected data comes from the second evaluation, and the credit evaluation model is improved based on the snowNLP tool, and the malicious brushing filtering function is added. Compared with the credit evaluation system commonly used in current online stores, the evaluation results of the paper are more accurate, detailed and intuitive, and may effectively reduce false brushing and threat review.

Shenyang City was the political, economic and cultural centre of the northeast China and was also a heavily polluted industrial city. The understanding of the distribution characteristics of air pollutants concentration and changes was still lacked. To reduce the impact of disturbing factors such as firecrackers in the traditional Chinese festivals, the observation period of the monitoring data was selected from 17th May to 21st July in 2016. The data sources were picked from eight national monitoring stations and the daily average concentration of the main air pollutants that included PM2.5, PM10, SO2, NO2 and O3. The overall analysis of distribution characteristics of the air pollutant was shown that the principal pollutants with highest frequency were O3 and PM10, the average proportion was 74.1% and 20.8% respectively.

In this paper, the characteristics of leukemia diseased cells, diseased cells existing classification methods were studied and analyzed, in order to solve classification categories leukemia diseased cells more characteristic dimensions of the problem of high, finite automata and kernel methods, and experimental verification the advantages of this method.

In many regions in China there is a wide distribution of dead-weight collapsible loess that experience frequent disasters resulting in enormous losses to national property. Loess collapsibility is the leading cause of disasters in loess areas. Many international scholars are working collaboratively to avoid property losses and human casualties caused by the collapsible loess. Loess collapsibility is closely related to the vertical permeability regularity, so the vertical permeability regularity should be the first critical factor taken into account in studying loess collapsibility. In Lanzhou city, the in-situ soaking test is carried out on an unsaturated natural loess foundation with a thickness of 36.5m, the test pit diameter is 40m, TDR moisture probes are embedded, and the test lasts 282 days. During the test, the vertical migration of water is observed and the temporal and spatial variations of volumetric water content are considered. In the detailed research of the vertical permeability regularity, the relation between permeability regularity and collapsibility are discussed. For shallow layer soil, soil volumetric water content reaches saturation at wetting front, the water flows downward due to gravity and the infiltration rate is larger. For deep layer soil, the moisture will increase because of the upper soil permeability and its own suction, but, due to soil compression caused by the occurrence of the upper soil collapsibility, the infiltration rate is significantly reduced. The temporal and spatial variations of water volumetric content can be used to determine whether a loess collapsible deformation has occurred. The limit permeability depth in this test is 25m, and the limit permeability depth can also be served as the collapsibility evaluation depth of the unsaturated natural Malan loess foundation.

This paper analyzes the characteristics of white blood cells, diseased cells during feature extraction, the introduction of anti-corrosion factor for microscopic image processing, experiments show that the method of classification and extraction of diseased cells have better results.

We compute all kaon and pion parton distribution amplitudes (PDAs) to twist-three and find that all of the pion’s distributions are symmetric and all of the kaon’s distributions are skewed in favour of the heavier s-quark, which are clear signals of dynamical chiral symmetry breaking (DCSB). And we can also notice that only the pseudotensor PDA can reasonably be approximated by its conformal limit. At any realistic energy scale, the pseudovector and pseudoscalar PDAs differ markedly from the corresponding functions in QCD’s conformal limit. We can use these PDAs as the inputs to study hard exclusive processes and get trustable results.