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In this paper, the deformation of the platform and canopy of a high-speed railway station is studied, and an online monitoring system for platform canopy deformation is designed to solve the problem of online monitoring of platform canopy deformation. Due to the conventional one-dimensional measurement has been difficult to meet the needs of high-speed railway industrial production and daily life. Nowadays, laser radar and binocular cameras for three-dimensional data measurement have gradually emerged. At present, there is almost no three-dimensional data acquisition equipment with high measurement accuracy, low price, and a high degree of automation in the market. Given the lack of this equipment in the market, this paper presents a three-dimensional data acquisition system based on a laser rangefinder. By collecting, processing, and analyzing the data of the platform and canopy, the purpose of prediction can be achieved, and then the abnormal response, damage, and degradation of the structure can be found in time. The study shows that the monitoring system is helpful to detect deformation and give early warning, and effectively prevent the occurrence of hazards.

In this paper, we put forward a multi-party quantum private comparison (MQPC) protocol with two semi-honest third parties (TPs) by adopting d-dimensional Bell states, which can judge the size relationship of private integers from more than two users within one execution of protocol. Each TP is permitted to misbehave on her own but cannot collude with others. In the proposed MQPC protocol, TPs are only required to apply d-dimensional single-particle measurements rather than d-dimensional Bell state measurements. There are no quantum entanglement swapping and unitary operations required in the proposed MQPC protocol. The security analysis validates that the proposed MQPC protocol can resist both the outside attacks and the participant attacks. The proposed MQPC protocol is adaptive for the case that users want to compare the size relationship of their private integers under the control of two supervisors. Furthermore, the proposed MQPC protocol can be used in the strange user environment, because there are not any communication and pre-shared key between each pair of users., 15 pages, 1 figure, 1 table

In the actual construction of an offshore wind farm, the layout of wind turbines directly affects the flow characteristics of each wind turbine. When the wind passes through the upstream unit, the work done at the hub of the downstream fan decreases, resulting in the wake effect. Therefore, on the premise of considering the wake flow, it is of great significance to study the optimization of fan arrangement. The research and selection of reasonable wind turbine arrangements have a significant effect on power generation efficiency and power output. In this paper, the improved Gauss model is used to simulate the wake flow, and the cost model that is more close to the actual construction is selected. By taking the number and distance of wind turbines as variables and the cost generated as the objective function, the research is carried out. The research is carried out in the process of automatic optimization through a particle swarm optimization algorithm.

Bioprinting is an emerging approach for constructing sophisticated tissue analogues with detailed architectures such as vascular networks, which requires bioink to fulfill the highly printable property and provide a cell-friendly microenvironment mimicking a native extracellular matrix (ECM). Here, we developed a human placental ECM-derived bioink (hp-bioink) meeting the requirements of 3D printing for printability and bioactivity. We first decellularized the human placenta, followed by enzymatic digestion, dialysis, lyophilization, and re-solubilization to convert the extracts into hp-bioink. Then, we demonstrated that 3%–5% of hp-bioink can be printed with self-standing and 1%–2% of hp-bioink can be embedded and printed within suspended hydrogels. Moreover, hp-bioink supports human umbilical vein endothelial cell assembly in vitro and angiogenesis in mice in vivo. Our research enriches the bank of human-derived bioinks, and provides a new opportunity to further accelerate bioprinting research and application.

A novel memristor-based multi-scroll hyperchaotic system is proposed. Based on a voltage-controlled memristor and a modulating sine nonlinear function, a novel method is proposed to generate the multi-scroll hyperchaotic attractors. Firstly, a multi-scroll chaotic system is constructed from a three-dimensional chaotic system by designing a modulating sine nonlinear function. Then, a voltage-controlled memristor is introduced into the above-designed multi-scroll chaotic system. Thus, a memristor-based multi-scroll hyperchaotic system is generated, and this hyperchaotic system can produce various coexisting hyperchaotic attractors with different topological structures. Moreover, different number of scrolls and different topological attractors can be obtained by varying the initial conditions of this system without changing the system parameters. The Lyapunov exponents, bifurcation diagrams and basins of attraction are given to analyze the dynamical characteristics of the multi-scroll hyperchaotic system. Besides, the field programmable gate array (FPGA) based digital implementation of the memristor-based multi-scroll hyperchaotic system is carried out. The experimental results of the FPGA-based digital circuit are displayed on the oscilloscope.

Azo-based pillar[6]arene supramolecular organic frameworks are reported for CO2 and N2 adsorption and separation by density functional theory and grand canonical Monte–Carlo simulation. Azo-based pillar[6]arene provides suitable environment for CO2 adsorption and selectivity. The adsorption and selectivity results show that introducing azo groups can effectively improve CO2 adsorption and selectivity over N2, and both CO2 adsorption and CO2 selectivity over N2 follow the sequence pillar[6]arene_N4 > pillar[6]arene_N2 > pillar[6]arene. Pillar[6]arene_N4 exhibits CO2 adsorption capacity of ∼ 1.36 mmol/g, and superior selectivity of CO2 over N2 of ∼ 116.75 with equal molar fraction at 1 bar (1 bar = 105 Pa) and 298 K. Interaction analysis confirms that both the Coulomb and van der Waals interactions between CO2 with pillar[6]arene frameworks are greater than that of N2. The stronger affinity of CO2 with pillar[6]arene_N4 than other structures and the larger isosteric heat differences between CO2 and N2 rendered pillar[6]arene_N4 to present the high CO2 adsorption capacity and high CO2 selectivity over N2. Our results highlight the potential of azo-functionalization as an excellent means to improve pillar[6]arene for CO2 capture and separation.

Soil organic matter is not only the condition for the survival and development of soil organisms, but also the product of the survival and development of soil organisms. Land use pattern is an important factor affecting the content and dynamic change of soil organic matter. There are significant differences in the spatial and temporal distribution and circulation of matter under different land use patterns, which interfere and adjust the cycle process of soil biochemistry, and the content of soil organic matter also changes. In this paper, the soils under four land use types, i.e., grassland, woodland, cultivated land and unused land, in the surrounding area of Yanshan Campus of Guilin University of Technology were selected as the research objects, and five samples of 10-20cm topsoil under different land use types were collected by diagonal method. The soil organic matter content was measured by hydration heat K2Cr2O7oxidation-colorimetry, and the differences and laws of soil organic matter content under different land use types were discussed. The results showed that soil organic matter content was closely related to land use patterns, and there were differences in organic matter content among different land use patterns, which was supported by F test of land use patterns. According to the average value of sample organic matter, the organic matter content of red soil under different land use patterns is cultivated land (3.89%) > unused land (3.02%) > grassland (1.25%) > forest land (1.12%). However, under the condition of α=0.01, there is no significant difference between woodland and grassland, while there is significant difference between woodland and cultivated land and unused land, while there is no significant difference between grassland and cultivated land and unused land.

In order to study the influence of vehicle body vibration caused by road excitation on the output performance of a vehicle piezoelectric electromagnetic hybrid energy harvester, the theoretical analysis of the energy harvester is carried out, and a corresponding electromechanical coupling model is established. The hybrid energy harvester includes a flutter piezoelectric energy harvester (FPEH) and an electromagnetic vibration energy harvester (EVEH). Sweep frequency experiments and wind tunnel experiments were carried out to verify the correctness of the coupling model. By establishing the road-vehicle coupling differential equations solving module, the vehicle body vibration under different road surfaces was simulated, and the influence of different roads on output performance is analyzed. The results show that when vehicle body vibration is not considered, the cut-in speed of the harvester is 32 km h−1. When the vehicle speed is higher than 32 km h−1, vehicle body vibration caused by road roughness will suppress the overall output performance. When the vehicle speed is less than 32 km h−1, the vibration of the vehicle body will cause the energy harvester to have no obvious cut-in wind speed. And the higher the road level, the stronger the body vibration, and the better the output performance when the vehicle speed is less than 32 km h−1. Under E-class road with vehicle body vibration considered, it has already power output at a vehicle speed of 20 km h−1. When the vehicle speed reaches 57 km h−1, the output power of hybrid FPEH and EVEH reach 1.74 and 2.51 mW under E-class road (2.88 and 3.25 mW under A-class road), respectively.

Red-fleshed apple (Malus niedzwetzkyana dieck) was used as the fermentation material, and the fermentation mode of red-fleshed apple cider was studied by using alcohol fermentation as control (CK), simultaneous malolactic fermentation (SIM) and sequential MLF (SEQ). The main chemical parameters, antioxidant activities and sensory quality were analyzed to evaluate the quality of red-fleshed apple cider. Compared with the cider without lactic acid bacteria, the total phenolics contents (TPC) and total anthocyanins contents (TAC) in MLF apple cider were significantly decreased, while the total flavonoids content (TFC) were significantly increased. Among them, the TPC and TAC in apple cider obtained by SIM were the highest, while the TFC in apple cider obtained by SEQ. In addition, compared with the control group, the pH of cider obtained by SEQ and SIM was significantly increased by about 0.25 units, while the total acidity was significantly decreased. Therefore the taste of cider obtained from SIM and SEQ were significantly improved, and the cider obtained by SIM got the highest score by sensory analysis, which scored the highest for floral and fruitiness notes. These results indicated that SIM was an effective way to produce red-fleshed apple cider.

With the development of Internet of Things technology, cloud computing technology, big data technology, and artificial intelligence technology, the application of these new technologies to rural life can help rural elderly care at home. The home care system for the elderly in rural areas is based on artificial intelligence technology and uses the Internet of things technology to collect real-time environmental parameters at home and to optimize the living environment. It uses intelligent image recognition technology to judge the behavior of the elderly and interlopers and gives effective early warning and alarm. It uses wearable devices to measure the health of the elderly in real-time. It uses the man-machine dialogue program to solve the life needs of the elderly to improve the well-being of the elderly life. It integrates big data and cloud computing technology to process the collected information.

Nanofibrillated cellulose (NFC) is deemed to be environmentally friendly, green and inexhaustible material. Herein, Nanofibrillated cellulose (NFC) large length-diameter ratio were prepared by enzymatic pretreatment and mechanical method, and it was added into pulp as reinforcing agent to improve the performance of paper. The retention and loss efficiency of NFC in the paper preparation process were studied, and the retention and loss efficiency were characterized by analyzing the mechanical properties of the paper. It was found that the retention and loss efficiency of NFC decreased with the increase of NFC content. The addition of retention system in papermaking process has a positive effect on the retention efficiency of NFC. NFC can be uniformly distributed in the paper up to 8% with low addition. In addition, retention system can improve the mechanical properties of paper with high NFC content. Compared with the base paper, tensile strength, roughness, stiffness and air permeability of the paper increased by 111.38%, 100.95%, 152.63% and 96.80% respectively.

Taking infant formula milk powder, an important food, as an example, this paper selects a total of 12 explanatory variables from three aspects: personal characteristics, family factors and psychological factors, takes consumers’ willingness to pay for food traceability labels as dependent variable Y, and adopts binary logistic regression model to understand and analyze the influencing factors of consumers’ willingness to pay for food traceability labels with big data collection and analysis. The results show that consumers’ age, education background, monthly family income, consumers’ trust in traceable labels and total family population will significantly affect consumers’ willingness to pay for food traceability labels; specifically, younger consumers are more willing to pay for food traceability labels, consumers with higher education are more inclined to pay for food traceability labels, consumers with higher income are more inclined to pay for food traceability labels, consumers with higher education are more inclined to pay for food traceability labels, and consumers with high trust in traceability labels are more inclined to pay for food traceability labels.

Urban boundaries, an essential property of cities, are widely used in many urban studies. However, extracting urban boundaries from satellite images is still a great challenge, especially at a global scale and a fine resolution. In this study, we developed an automatic delineation framework to generate a multi-temporal dataset of global urban boundaries (GUB) using 30 m global artificial impervious area (GAIA) data. First, we delineated an initial urban boundary by filling inner non-urban areas of each city. A kernel density estimation approach and cellular-automata based urban growth modeling were jointly used in this step. Second, we improved the initial urban boundaries around urban fringe areas, using a morphological approach by dilating and eroding the derived urban extent. We implemented this delineation on the Google Earth Engine platform and generated a 30 m resolution global urban boundary dataset in seven representative years (i.e. 1990, 1995, 2000, 2005, 2010, 2015, and 2018). Our extracted urban boundaries show a good agreement with results derived from nighttime light data and human interpretation, and they can well delineate the urban extent of cities when compared with high-resolution Google Earth images. The total area of 65 582 GUBs, each of which exceeds 1 km2, is 809 664 km2 in 2018. The impervious surface areas account for approximately 60% of the total. From 1990 to 2018, the proportion of impervious areas in delineated boundaries increased from 53% to 60%, suggesting a compact urban growth over the past decades. We found that the United States has the highest per capita urban area (i.e. more than 900 m2) among the top 10 most urbanized nations in 2018. This dataset provides a physical boundary of urban areas that can be used to study the impact of urbanization on food security, biodiversity, climate change, and urban health. The GUB dataset can be accessed from http://data.ess.tsinghua.edu.cn.

The water-bearing system in the karst area is complex and changeable. Water in the water-bearing medium has the characteristics of coexistence of fissure flow and pipeline flow, coexistence of laminar and turbulent flow, coexistence of linear and nonlinear flow, coexistence of continuous flow and isolated water body. In areas where economic development is relatively backward, most areas lack data or no data. Based on the characteristics of the karst area in the southwest, this paper proposes a thinking evolution algorithm to optimize the gray neural network model. This method improves the optimization ability of runoff prediction models and effectively overcomes human neural network learning. The speed is slow and there are inherent shortcomings of local minima. After studying the daily flow forecast of Zhenlong Station, it is shown that the relative error of the prediction is small and can be effectively used for short-term runoff prediction.

The determination of sand content is related to the accuracy of soil and water loss measurement. With the development of science and technology, there are many advanced sediment content measurement technologies. However, due to the differences and complexity of soil conditions in various regions, The applicability of this method for sand content measurement needs to be verified. This article explores the method for measuring sand content in red soil on the conditions of simulated rainfall and runoff experiments, and verifies the measurement accuracy of water samples with different sediment contents using the gravimetric method. The results show that when the sediment content is small, the error of the specific gravity method is large, and its accuracy increases with the increase of the sediment content, and the accuracy is the highest when the sediment content is about 40g/L. In addition, the fitting curve is used in this paper. The sediment content is measured and compared with the drying method. The experimental results show that the measurement accuracy is higher than the specific gravity method, but the results are different from the drying method.

We simulate pulse shaping of bright–dark vector soliton pair in an optical fiber system. Through changing input pulse parameters (amplitude ratio, projection angle, time delay, and phase difference), different kinds of pulse shapes and spectra can be generated. For input bright–dark vector soliton pair with the same central wavelength, “2+1”- and “2+2”-type pseudo-high-order bright–dark vector soliton pairs are achieved. While for the case of different central wavelengths, bright–dark vector soliton pairs with multiple pulse peaks/dips are demonstrated with appropriate pulse parameter setting.

The low-resistance NiAu/Ni/Au ohmic contact in p-type AlGaN/GaN semiconductor was carefully investigated by electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) after two-step annealing at 550 and 750°C. It is shown that complicate double-direction diffusion and reaction occurred in the metal layer and underlying GaN layer. The four metal stacks of Ni/Au/Ni/Au turned into almost one layer and an intimate relationship established at NiAu/GaN boundary, which should play a primary role in ohmic contact to reduce the contact barrier. At the intimate interface, the metal layer close to the contact was enriched with Ga and Au, and the GaN upper layer was metalized by Au and Ni. Numerous Ni atoms were oxidized and formed dispersive NiO nanoclusters in the metal layer, which might have a hindering effect on upward migration of Ga atoms. Dislocations connected with the contact boundary absorbed interstitial atoms of Au or Ni may serve as channels for current carrier transportation. Thus, a low-resistance p-GaN ohmic contact can be obtained by the above combination of these microstructural characteristics.

The ion beams extracted from an Electron Cyclotron Resonance (ECR) ion source always exist strong transverse coupling effect that is caused by the field of the axis mirror magnets and the extraction solenoid. In order to obtain the four-dimensional (4D) characteristic matrix with coupling elements, a Pepper Pot probe was developed and used to obtain the full 4D transverse phase space distribution of the low energy beam extracted from the ECR ion source at IMP. This paper describes the detailed design and image processing procedure of Pepper Pot probe, especially the analysis results verification compared to another type emittance meter. The first 4D transverse phase space distribution measurement data of oxygen beams from the LECR4 experimental platform are presented and discussed.

This study uses CFPS (2010) database researching issues related to the formation of values. We use the OLS (Ordinary Least Square) method to identify the long-term effects of this group of values on those who were enrolled in school between 1986 and 1989 and aged between 15 and 22 in two dimensions, the year of birth and the highest degree. Between 1986 and 1989, two large-scale student movements took place in China. Through the use of social survey data at the individual level, the regression found that those affected by the school sentiment were more concerned with social events and less concerned with social relationships.

Urban populations are expected to increase by 2–3 billion by 2050, but we have limited understanding of how future global urban expansion will affect urban heat island (UHI) and hence change the geographic distributions of extreme heat risks. Here we develop spatially explicit probabilistic global projections of UHI intensification due to urban land expansion through 2050. Our projections show that urban land areas are expected to expand by 0.6–1.3 million km2 between 2015 and 2050, an increase of 78%–171% over the urban footprint in 2015. This urban land expansion will result in average summer daytime and nighttime warming in air temperature of 0.5 °C–0.7 °C, up to ∼3 °C in some locations. This warming is on average about half, and sometimes up to two times, as strong as that caused by greenhouse gas (GHG) emissions (multi-model ensemble average projections in Representative Concentration Pathway 4.5). This extra urban expansion-induced warming, presented here, will increase extreme heat risks for about half of the future urban population, primarily in the tropical Global South, where existing forecasts already indicate stronger GHG emissions-warming and lack of adaptive capacity. In these vulnerable urban areas, policy interventions to restrict or redistribute urban expansion and planning strategies to mitigate UHIs are needed to reduce the wide ranges of impacts on human health, energy system, urban ecosystem, and infrastructures.

High-quality dielectric/Ge interface and low gate leakage current are crucial issues for high-performance nanoscaled Ge-based complementary metal–oxide–semiconductor (CMOS) device. In this paper, the interfacial and electrical properties of high-k HfGdON/LaTaON stacked gate dielectric Ge metal–oxide–semiconductor (MOS) capacitors with different gadolinium (Gd) contents are investigated. Experimental results show that when the controlling Gd content is a suitable value (e.g., ∼ 13.16%), excellent device performances can be achieved: low interface-state density (6.93 × 1011 cm−2 · eV−1), small flatband voltage (0.25 V), good capacitance–voltage behavior, small frequency dispersion, and low gate leakage current (2.29× 10−6 A/cm2 at V g = V fb + 1 V). These could be attributed to the repair of oxygen vacancies, the increase of conduction band offset, and the suppression of germanate and suboxide GeO x at/near the high k/Ge interface by doping suitable Gd into HfON.

CsPbBr3 nanocrystal is used as the saturable absorber (SA) for mode-locking Tm-doped fiber laser in a ring fiber cavity. The modulation depth, saturable intensity, and non-saturable loss of the fabricated SA are 14.1%, 2.5 MW/cm2, and 5.9%, respectively. In the mode-locking operation, the mode-locked pulse train has a repetition rate of 16.6 MHz with pulse width of 24.2 ps. The laser wavelength is centered at 1992.9 nm with 3-dB spectrum width of 2.5 nm. The maximum output power is 110 mW with slope efficiency of 7.1%. Our experiment shows that CsPbBr3 nanocrystal can be used as an efficient SA in the 2- μ m wavelength region.

We obtain bi-component Coulomb crystals using laser-cooled 40Ca+ ions to sympathetically cool 9Be+ ions in a linear Paul trap. The shell structures of the bi-component Coulomb crystals are investigated. The secular motion frequencies of the two different ions are determined and compared with those in the single-component Coulomb crystals. In the radial direction, the resonant motion frequencies of the two ionic species shift toward each other due to the strong motion coupling in the ion trap. In the axial direction, the motion frequency of the laser-cooled 40Ca+ is impervious to the sympathetically cooled 9Be+ ions because the spatially separation of the two different ionic species leads to the weak motion coupling in the axial direction.

Microwave receiver is a special equipment used to receive radio signals in radio telescope. The noise temperature of receiver is an important target to test sensitivity. The lower the noise temperature is, the higher the sensitivity is. Therefore, the measurement of noise temperature is very important. The classical cold and ambient load method can measure noise temperature well, but it can not be carried out during observation. In addition, the performance of microwave devices is not unchanged, and noise temperature will vary with the ambient temperature and test equipment, so real-time measurement of noise temperature is important. We set up a noise temperature measurement system based on normal and high temperature load method. Through this system, noise temperature can be calculated by measuring the radiation power and temperature of blackbody at normal temperature and after heating to 150°C. Compared with results of the cold and ambient load method, the maximum test error is 12.3% in five tests, and the other test errors are less than 10%. The results can confirm that the normal and high temperature load method could be hopeful to satisfy the normal test requirements of centimeter-band normal temperature receiver.

Wear is the main failure form of unfolding wheel for bearing steel ball. When the wear increase to a certain extent, the function of the wheel is ineffective. According to the unfolding wheel structure and unfolding principle, the critical failure condition of the unfolding wheel is established. Based on the classical Archard wear model and combined with the finite element method, a discrete Archard wear model is proposed, and a prediction model of the wear life of the unfolding wheel is established. Using Ansys software to simulate the wear of the unfolding wheel, the relationship equation between the wear depth and the wear times is obtained, and the wear life prediction of the unfolding wheel is carried out.