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Abstract In order to solve the network congestion problem caused by burst service flows in heterogeneous cognitive radio networks (Het‐CRN), a two‐stage dual‐threshold random early detection (TD‐RED) control mechanism is proposed here. Meanwhile, a three‐state Markov modulated Poisson process (MMPP‐3) is used to model the burst service to analyze its arrival in depth. Moreover, a performance evaluation system (PES) is proposed to quantify the interference of burst services to different classes of services and their quality of service, which can comprehensively evaluate the performance enhancement of the TD‐RED control mechanism for each service. The system examines performance metrics such as packet loss rate, average delay, average captain etc. PES simulation results show that TD‐RED significantly reduces the packet rejection rate and transmission delay compared to the no congestion control (NCC) and random early detection (RED) methods, thus providing superior quality of service to all services. thereby providing a superior quality of service to cognitive users. Its lower average captain fully proves that TD‐RED can effectively alleviate congestion.

Abstract Durability is one of the technical bottlenecks restricting fuel cell electric vehicle development. As a result, significant time and resources have been invested in research related to this area worldwide. Current durability research mainly focuses on the single cell and stack levels, which is quite different from the usage scenarios of actual vehicles. There is almost no research on developing durability test cycles on the fuel cell system level. This paper proposes a universal model for developing a durability test cycle for fuel cell system based on the China automotive test cycle. Large-scale comparison tests of the fuel cell systems are conducted. After 1000 h test, the output performance degradation of three mass-produced fuel cell system is 14.49%, 9.59%, and 4.21%, respectively. The test results show that the durability test cycle proposed in this paper can effectively accelerate the durability test of the fuel cell system and evaluate the durability performance of the fuel cell system. Moreover, the methodology proposed in this paper could be used in any other test cycles such as NEDC (New European Driving Cycle), WLTC (Worldwide Harmonized Light Vehicles Test Procedure), etc. And it has comprehensive application value and are significant for reducing the cost of durability testing of fuel cell systems and promoting the industrialization of fuel cell electric vehicles.

Understanding thermal shock behaviors and related damage mechanism of needled C/C–SiC composites is of much significance to their engineering application. In this study, a multi-scale framework is developed to characterize the degeneration of mechanical properties and damage accumulation in the needled composites comprehensively across different scales under cyclic thermal shock. Thermal shock temperature and thermal shock cycles are involved in the simulation, and the outcomes are verified with experiments performed in an inert atmosphere. The results show that the strength of C/C–SiC composites decreases continuously as the test temperature and thermal shock cycles increase. Meanwhile, the fracture of the material mainly occurs in the short-fiber felt. The damage initiates in the short-fiber felt near the contact area of the non-woven (NW) fiber tow and the needle-punched (NP) fiber tow when the test temperature is low (about 900 °C), and gets severe as temperature increases. With the increase of thermal shock cycles at 1700 °C, the fracture of the composites is more significant, and spreads from inside to the outer surface. Based on the multi-scale simulation and the microstructure of the composites after TSR tests, the primary damage mechanisms in the short-fiber felt are identified as ceramic-matrix damage and interface debonding.

Abradable seal coatings represent a critical technology within the realm of advanced power systems, designed to minimize airflow channel leakage, thereby reducing energy consumption and enhancing overall efficiency. In the present study, CuAl/BN, CuAlLaF3/BN, and CuAlY/BN abradable seal coatings were prepared using plasma spraying technology. Both the as-deposited coatings and high-temperature oxidation-treated coatings were comprehensively investigated by means of scanning electron microscopy (SEM), open-circuit potentials (OCP), potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), salt-spray corrosion testing, and bond strength evaluations. The results show that the addition of rare earth elements to the CuAl/BN coatings does not enhance the corrosion resistance of the coatings and even leads to a decrease in the corrosion resistance of the coatings. In contrast, the CuAlY/BN coatings exhibited a significant improvement in corrosion resistance following an oxidation treatment at 550 °C. This enhancement is attributed to the yttrium (Y) element, which facilitates the formation of passivation films and confers a resistance effect, thereby bolstering the coatings’ resistance to corrosion. The bond strength of the high-temperature oxidation-treated CuAlY/BN coating was improved by about 30% after 960 h of salt-spray corrosion.

ABSTRACT Accurate crop classification, crucial for a macro-level understanding of food production, formulating relevant agricultural policies, and predicting comprehensive agricultural productivity, enables precise crop distribution. In remote sensing image classification, feature selection and representation play a pivotal role in accuracy. An augmented U-Net algorithm, named ASPP-SAM-UNet, integrating spatial attention mechanisms and multi-scale features is proposed for the enhancement of typical crop classification accuracy in remote sensing. The ASPP-SAM-UNet design integrates features over multiple scales, boosts the representational capacity of shallow features, and expands the neural network’s receptive field by incorporating Atrous Spatial Pyramid Pooling (ASPP) into the convolutional components of the standard U-Net encoder via residual connections. The integration of the residual module allows for a profound fusion of deep and shallow features, thereby enhancing their utility. The spatial attention mechanism amalgamates spatial and semantic information, empowering the decoder to reclaim more spatial information. This study focused on Bayan County, Harbin City, Heilongjiang Province, China, employing GF-6 WFV remote sensing images for crop classification. Empirical outcomes showed a significant improvement in classification accuracy with the advanced algorithm, boosting the overall accuracy (OA) from 89.49 to 92.80%. Specifically, the segmentation accuracy for maize, rice, and soybean increased from 89.90, 89.96, and 87.37% to 93.47, 94.82, and 89.35%, respectively. The suggested algorithm offers a pioneering performance standard for crop classification leveraging GF-6 WFV remote sensing imagery.

Energy consumption is essential for evaluating the competitiveness of fuel cell electric vehicles. A critical step in energy consumption measurement is measuring hydrogen consumption, including the mass method, the P/T method, and the flowmeter method. The flowmeter method has always been a research focus because of its simple operation, low cost, and solid real-time performance. Current research has shown the accuracy of the flowmeter method under specific conditions. However, many factors in the real scenario will influence the test result, such as unintended vibration, environment temperature, and onboard hydrogen capacity calibration. On the other hand, the short-cut method is also researched to replace the run-out method to improve test efficiency. To evaluate whether the flowmeter method basing on the short-cut method can genuinely reflect the hydrogen consumption of an actual vehicle, we research and test for New European Driving Cycle (NEDC) and China Light-Duty Vehicle Test Cycle (CLTC) using the same vehicle. The results show that the short-cut method can save at least 50% of the test time compared with the run-out method. The error of the short-cut method based on the flowmeter for the NEDC working condition is less than 0.1%, and for the CLTC working conditions is 8.12%. After adding a throttle valve and a 4L buffer tank, the error is reduced to 4.76% from 8.12%. The test results show that hydrogen consumption measurement based on the flowmeter and short-cut method should adopt corresponding solutions according to the scenarios.

This article details a method for preparing cermet matrix composites via Fast hot pressing (FHP) sintering technology and emphasizes their potential use in extremely high-temperature settings. The material primarily consists of NiCr alloy, Cr3C2, and LaF3. An in-depth investigation was conducted on the tribological properties of the specimen by conducting sliding tests against a Si3N4 ball at varying temperatures, including room temperature (RT), 400 °C, 600 °C, and 800 °C. Advanced techniques such as scanning electron microscopy, micro-XRD, and micro-Raman spectroscopy were employed to examine the friction surfaces formed under different frictional temperatures. The findings reveal a uniform composition and high density within the composites. It is noteworthy that as the LaF3 content increases, the hardness of the ceramic phase diminishes. Conversely, the hardness of the alloy phase augments with the addition of LaF3, provided that its content remains below 15 wt%. The composite material containing 15 wt% LaF3 demonstrates superior hardness values, with the ceramic phase reaching HV1412 and the alloy phase achieving HV384. Furthermore, the coefficient of friction of the composite material was evaluated. The coefficient of friction of the composite is between 0.74 and 0.4 and the wear rate is 4.46 × 10−6–5.72 × 10−5 mm3N−1m−1 from room temperature to 800 °C. The lubrication behavior at low temperature is mainly attributed to the lubricating effect of LaF3, and at high temperature it is due to the tribochemical reaction to form LaCrO3 with good lubricating properties, which plays a synergistic lubricating role with Cr2O3.

HfO2 has become a promising thermal barrier coating material due to its similarity in structure and chemical properties with ZrO2 and its higher phase structure transition temperature. However, the fracture toughness of HfO2 is not ideal, greatly limiting its application. In this report, we find a special sandwich structure of ceramics, comprising a cubic (C) phase /monoclinic (M) phase/cubic (C) phase. The microstructural evolution and mechanical properties of these ceramics were investigated under annealing at 1500 °C. The results indicate that, with an increase in annealing duration, there was a gradual augmentation in the proportion of the monoclinic (M) phase and the fracture toughness increased from 2.18 MPa·m0.5 to 2.83 MPa·m0.5 after 48 h of annealing, which is higher than many potential TBC materials. The residual compressive stress present in the M phases during the progression of crack propagation served to facilitate the bridging and deflection of cracks. As such, this process led to the alleviation of stress concentration at the crack tip, ultimately enhancing the toughening effect.

Fuel cell electric vehicles are generally considered to have broad development prospects due to their high efficiency and zero emissions. The governments of the United States, Japan, the European Union, and China are taking action to promote the development of the industry. In 2020, China launched a fuel cell electric vehicle demonstration project, and there will be 30∼50 thousand FCEVs included in this project by the end of 2025. How to standardize the consistency of data and develop a unified and accurate evaluation method is an important topic. The difficulty is how to keep balance among scientificity, neutrality and feasibility in the evaluation method. In order to evaluate the performance of vehicles in demonstration operation projects, China has issued the ”Fuel Cell Electric Vehicle Test Specifications”, which is an important guide for the future development of fuel cell electric vehicles in China. This paper compares the test methods for critical parameters in this specifications with those used in the United States and Japan. It explains China’s technical considerations in detail, including fuel cell system rated power, the volume power density of the fuel cell stack, fuel cell system specific power, fuel cell system sub-zero cold start, and fuel cell electric vehicle range contributed by hydrogen.For the volume power density of the fuel cell stack as an example, both the US Department of Energy and Japan’s New Energy and Industrial Technology Development Organization have proposed technical goals. However, the lack of specific and detailed test methods has confused the industry. We propose a new test method using bipolar plate measurement based on scientificity, feasibility and neutrality This is the first time to define the measuring method of the volume and specific power density of the fuel cell stack. For sub-zero cold start, we put forward a feasible scheme for sub-zero cold start at the system level. For range contributed by hydrogen, we propose a new test method that can distinguish the contributing of electric and hydrogen energy. Furthermore, a hydrogen-to-electric conversion formula is proposed to calculate the equivalent hydrogen consumption, which makes it possible to compare the energy consumption between plug-in and non-plug-in vehicles. At the same time, this approach is significant in helping fuel cell-related enterprises to understand the formulation of China’s “Fuel Cell Electric Vehicle Test Specifications”. It should also be helpful for guiding product design and predicting fuel cell electric vehicle policy direction in China.

Introduction: Papillary thyroid cancer (PTC) is the most common endocrine malignancy. However, different PTC variants reveal high heterogeneity at histological, cytological, molecular and clinicopathological levels, which complicates the precise diagnosis and management of PTC. Alternative splicing (AS) has been reported to be potential cancer biomarkers and therapeutic targets.Method: Here, we aim to find a more sophisticated molecular subclassification and characterization for PTC by integrating AS profiling. Based on six differentially expressed alternative splicing (DEAS) events, a new molecular subclassification was proposed to reclassify PTC into three new groups named as Cluster0, Cluster1 and Cluster2 respectively.Results: An in silico prediction was performed for accurate recognition of new groups with the average accuracy of 91.2%. Moreover, series of analyses were implemented to explore the differences of clinicopathology, molecular and immune characteristics across them. It suggests that there are remarkable differences among them, but Cluster2 was characterized by poor prognosis, higher immune heterogeneity and more sensitive to anti-PD1 therapy. The splicing correlation networks proved the complicated regulation relationships between AS events and splicing factors (SFs). An independent prognostic indicator for PTC overall survival (OS) was established. Finally, three compounds (orantinib, tyrphostin-AG-1295 and AG-370) were discovered to be the potential therapeutic agents.Discussion: Overall, the six DEAS events are not only potential biomarkers for precise diagnosis of PTC, but also the probable prognostic predictors. This research would be expected to highlight the effect of AS events on PTC characterization and also provide new insights into refining precise subclassification and improving medical therapy for PTC patients.

ObjectiveTo explore the effects of yam gruel on blood glucose and insulin resistance in patients with gestational diabetes mellitus (GDM).MethodsA total of 144 patients with GDM were recruited from the Obstetric Department of 900th Hospital of Joint Service Support Force of Chinese People's Liberation Army (Center Hospital Area and Cangshan Hospital Area) and Fujian Provincial Jinshan Hospital from July 2019 to December 2020, which were randomly divided into the control group and the observation group, with 72 cases in each group. The control group was given routine treatment and nursing care including regular outpatient examination, diet guidance, exercise guidance, blood glucose self-monitoring and health education. The observation group was given yam gruel on the basis of the routine treatment and care in the control group. Yam gruel was used to replace the carbohydrates in the breakfast [125 g peeled yam, 70 kcal (1 kcal=4.186 kJ)] under the condition of maintaining the total calories of breakfast. The yam gruel was taken every morning, five times a week, continous treatment for 10 weeks. The difference of blood glucose indicators [fasting blood glucose (FBG), two-hour postprandial blood glucose (2 h PBG), glycosylated hemoglobin (HbA1c)], insulin resistance indicators [fasting serum insulin (FINS), homeostasis model assessment insulin resistance index (HOMA-IR)], and pregnancy outcome indicators (delivery method, adverse pregnancy outcome) between two groups.Results① Blood glucose indicators: compared with before intervention, 2 h PBG in the two groups after intervention for four,eight and ten weeks were significantly decreased, and HbA1c in the two groups after intervention for ten weeks was significantly increased, the differences were statistically significant (PPPP>0.05). Compared with the control group, FINS and HOMA-IR in the observation group after intervention for ten weeks were significantly decreased, the differences were statistically significant (PP>0.05).ConclusionYam gruel can effectively improve blood glucose and IR in patients with GDM, but the effect of improving pregnancy outcomes is not obvious, which is worthy of clinical application.

Abstract The mud cake is easily formed during the tunnel boring machine (TBM) excavation in clay soils or rocks containing clay minerals. Mud cake will lead to soil disturbance of tunnel face, clogging cutterhead and even affect the construction efficiency and personnel safety. In this study, a discrimination method of mud cake formation based on cutterhead temperature was proposed. An online monitoring system was designed and installed on the slurry balance TBM. The results show that: (a) the cutterhead temperature data can be reliably detected and transmitted by the system; (b) in a tunneling cycle, the temperature at some positions of the cutterhead will increase first and then decrease; (c) during the field test, the temperature variation is around 2.5 °C under the normal condition, but the temperature variation will increase more than 50 °C due to the mud cake or geological change; (d) compared with the cooling rate, mud cake formation can be accurately discriminated.

Objective To prepare the tumor targeting multifunctional composite nanoparticles (DIPP-NPs) by encapsulating sinoporphyrin sodium (DVDMS), IR780 and perfluorinated hexane (PFH), evaluate their physicochemical properties, and explore the synergistic enhancement of sonodynamic therapy (SDT) between DVDMS and IR780. Objective DIPP-NPs were synthesized via double emulsion and then characterized. The changes of nanoparticles before and after ultrasonic irradiation were observed by optical microscopy. Ultrasonic and photoacoustic imaging systems were used to evaluate the imaging capability in vitro. Targeting ability in vitro was evaluated by confocal laser scanning microscopy. The production of reactive oxygen species (ROS) was demonstrated by singlet oxygen detection (SOSG). CCK-8 assay was used to detect the cytotoxicity and synergistic enhancement of SDT in murine mammary carcinoma cell line 4T1. The synergistic enhancement of SDT in 4T1 xenograft mouse model was evaluated by measuring tumor volume and weight to calculate the inhibitory rates. Results DIPP-NPs were successfully prepared, as uniform round-shaped particles, 341.17±16.97 nm in diameter and -12.77±0.88 mV in Zeta potential. The encapsulation rate of DVDMS and IR780 was (92.84±1.58) % and (96.57±1.48) %, respectively. After irradiated with ultrasonic, DIPP-NPs were getting bigger and bigger in diameter under a optical microscope. Meanwhile, ultrasound imaging results showed that the ultrasound signals were enhanced with prolonged irradiation time. In addition, photoacoustic imaging results showed that the photoacoustic signal intensity was increased with the increment of nanoparticle concentration. Laser confocal microscopy demonstrated that there were more nanoparticles around 4T1 cells in DPP-NPs, IPP-NPs and DIPP-NPs groups than in PP-NPs group. SOSG detection results showed that the production of ROS was gradually increased with prolonged irradiation time. CCK-8 assay indicated that there was no obvious cytotoxicity of the nanoparticles and the cell viability in DIPP-NPS+US group was (56.04±2.28)%, which was obviously lower than that in DPP-NPS+US [(76.83±1.52)%] and IPP-NPS +US groups [(74.03±2.64)%, both P < 0.05]. Xenograft experiment showed that the inhibitory rate was (73.28±.58)% for tumor volume, and (75.76±3.49)% in weight in DIPP-NPS+US group, which were significantly higher than those in DPP-NPS+US [(46.93±4.41)%, (43.50±2.27)%] and the IPP-NPS+US groups [(47.44±1.27)%, (44.87±4.30)%, P < 0.05]. Conclusion The tumor-targeting multifunctional composite nanoparticles DIPP-NPs are successfully prepared, which have a good synergistic enhancement of SDT effectiveness.

Plant resistance against insects mainly depends on nutrient restriction and toxic metabolites, but the relative importance of nutrition and toxins remains elusive. We examined performance, nutrition ingestion, and transcriptome response of the English grain aphid, Sitobion avenae, feeding on resistant Xiaoyan 22 (XY22) and susceptible Xinong 979 (XN979) wheat cultivars. Aphids had lower body weight and fecundity when feeding on XY22 than on XN979, although the phloem sap of XY22 had a higher nutritive quality (in terms of amino acid:sucrose ratio). Aphids feeding on XY22 also had a lower honeydew excretion rate than those on XN979, suggesting that aphids ingested less phloem sap from XY22. The transcriptome data showed 600 differentially expressed genes (DEGs), and 11 of the top 20 KEGG pathways significantly enriched in DEGs were involved in nutrient metabolism. We found 81 DEGs associated with the metabolism of sugars, lipids, and amino acids, 59 of which were significantly downregulated in aphids feeding on XY22. In contrast, there were 18 DEGs related to detoxifying metabolism, namely eight UDP-glucuronosyltransferases, six cytochromes P450 monooxygenases, one glutathione S-transferase, two ATP-binding cassette transporters, and one major facilitator superfamily transporter; 12 of these were upregulated in the aphids feeding on XY22. Our results indicated that both the quantity and quality of phloem nutrition available to aphids are critical for the growth and development of aphids, and the higher resistance of XY22 is mainly due to the reduction in phloem sap ingested by aphids, rather than toxic metabolites.

Objective To prepare CREKA peptide-modified docetaxel (DTX) loaded liposomes (CREKA-lipo-DTX) and to evaluate their targeted binding ability and anti-proliferative activity in vitro. Methods Firstly, Michael addition reaction was used to synthesize the targeted part DSPE-PEG2000-CREKA, and then CREKA-lipo-DTX was prepared by thin film hydration-ultrasound method, and its basic characterization was evaluated. Both PC-3 cells and RWPE-1 cells were divided into 3 groups respectively (n=3): blank control group, PEG-lipo-DiI group and CREKA-lipo-DiI group. After co-incubation with the cells, the cellular uptake of liposomes was analyzed qualitatively and quantitatively by laser confocal microscopy and flow cytometry respectively, so as to evaluate the targeting effect of CREKA modified vector on PC-3 cells. The cellular uptake of liposomes was analyzed qualitatively and quantitatively by laser confocal microscopy and flow cytometry respectively. The anti-proliferative activity of CREKA-lipo-DTX was evaluated by CCK-8 assay and Annexin V-PI apoptosis detection kit on blank control group, free DTX group, PEG-lipo-DiI group and CREKA-PEG-DiI group of PC-3 cells. Results CREKA-lipo-DTX was successfully prepared, with an average particle size of 130.37±1.44 nm, and encapsulation rate of (91.93±4.64)%. The obtained drug carrier had good stability and showed good slow-release behavior in vitro. The results of laser confocal microscopy and flow cytometry analysis indicated that the uptake of CREKA-modified liposomes by PC-3 cells was significantly increased (P < 0.05) when compared with the unmodified liposome group (PEG-lipo-DiI), while no such difference was seen in RWPE-1 cells (P>0.05). In vitro anti-tumor experimental results suggested that enhanced killing effect of DTX on PC-3 cells and significantly increased numbers of early and late apoptotic PC-3 cells were observed in the CREKA-lipo-DTX group when compared with the free DTX and PEG-lipo -DTX groups (P < 0.05). Conclusion A high-efficiency and low-toxicity lipoid drug delivery system with long cycle and tumor specific targeting characteristics has been successfully prepared, which can specifically target PC-3 cells in vitro, and thus can improve the anti-tumor effect of the carrier in vitro.

Objective To prepare a novel nanoparticle carrying iron(Ⅱ) phthalocyanine (FePc) coupled with aptamer AS1411 for targeting human breast cancer MCF-7 cells and evaluate its physicochemical properties, targeting ability to MCF-7 cells, photoacoustic/ultrasonic multimodal imaging capabilities, photothermal performance, photoinduced phase transitions in vitro and multimodal imaging performance in vivo. Methods FePc-encapsulated non-targeted nanoparticles (PLGA@FePc@PFP) were prepared by a two-step phacoemulsification method, and the targeted nanoparticles (AS1411-PLGA@FePc@PFP NPs) were prepared by combining the aptamer AS1411 modified with NH2 and the PLGA@FePc@PFP nanoparticles using the carbodiimide method. The physicochemical properties of AS1411-PLGA@FePc@PFP NPs were detected, and laser confocal microscopy and flow cytometry were used to evaluate the binding between AS1411 and the nanoparticles. CCK-8 assay was used to detect the cytotoxicity of AS1411-PLGA@FePc@PFP; laser confocal microscopy was used to observe the in vitro targeting ability of the nanoparticles; photoacoustic and ultrasonic imagers were used to test their imaging performance and targeting ability both in vitro and in vivo. Near-infrared laser (660 nm) and thermal imagers were used to test the in vitro photothermal conversion abilities of the nanoparticles, and the changes of the nanoparticles after laser irradiation were observed under an optical microscope. The temperature change of AS1411-PLGA@FePc@ PFP in tumor-bearing nude mice was detected in response to 660 nm laser irradiation. Results AS1411-PLGA@FePc@PFP was successfully prepared, which had an average diameter of 208.03±8.96 nm with a narrow particle size distribution, a mean zeta potential of -10.8±1.14 mV, and a FePc encapsulation rate of (83.96±1.61)%. The results of CCK-8 assay showed that the nanoparticles at varying concentrations had no obvious cytotoxicity. Flow cytometry showed an efficient binding of AS1411 with the nanoparticles had a binding rate of (93.31±2.58)%. Laser confocal analysis showed that there were significantly more nanoparticles around MCF-7 cells in the targeted group than in the non-targeted group. Laser irradiation caused the temperature of the nanoparticles carrying FePc to increase rapidly with time, and the phase change of the nanoparticles was observed under an optical microscope, suggesting good photothermal conversion ability of the nanoparticles. Photoacoustic imaging results showed that compared with nanoparticles without FePc, AS1411-PLGA@FePc@PFP produced strong photoacoustic signals, and the signal intensity showed a positive linear correlation with the nanoparticle concentration. Ultrasound and imaging results showed FePc in AS1411-PLGA@FePc@PFP achieved good photothermal conversion in a concentration-dependent manner for enhancing the effect of ultrasound imaging. In the tumor-bearing nude mice, the photoacoustic signal values in the xenograft were 1.26±0.06 and 0.30±0.01 at 6 h after tail vein injection of AS1411-PLGA@FePc@PFP and PLGA@FePc@PFP, respectively, showing a significant difference in their signal intensity (P < 0.05); in vivo ultrasound/contrast imaging also demonstrated a significant difference in the signal value after laser irradiation between the targeted group and the non-targeted group (P < 0.05). After laser irradiation, the tumor temperature in the targeted nanoparticle group was 50.53±0.56 ℃, as compared with 40.63±0.78 ℃ in the non-targeted group. Conclusion A multimodal molecular probe AS1411-PLGA@FePc@PFP for breast cancer has been successfully prepared, which has a good photothermal effect and can be potentially used for photoacoustic/ultrasound multimodal imaging of breast cancer.

Long-distance oil and gas pipelines buried in permafrost areas will inevitably encounter typical geological disasters, such as frost heave and thaw settlement and sliding, which easily cause pipeline displacement, bending, or deformation. When there are certain defects in the pipeline, additional complex, external stress will further lead to the failure of the pipeline or weld and can even lead to serious accidents such as pipeline leakage, pipe burst, or fracture. This paper introduces in detail the typical defects and risks of buried pipelines in permafrost areas and summarizes the in-line inspection technologies, off-line inspection technologies, and integrated monitoring systems for pipelines in the pipeline industry. Regarding pipelines in permafrost areas, in-line inspection methods may be employed. These include magnetic flux leakage, electromagnetic eddy current, ultrasonic, IMU, and electromagnetic acoustic transducer inspections. Off-line inspection is also one of the important means of inspecting a pipeline in a permafrost area. Indirect inspection is combined with verification by direct inspection to check and evaluate the integrity of the anticorrosive coating and the effectiveness of the cathodic protection for the pipeline. Meanwhile, considering the external environment of a pipeline in a permafrost area, a monitoring system should be developed and established. This paper discusses and projects the future development of related technologies, which provides reference for the construction and operation of pipelines in permafrost areas.

Wireless charging technology has become an important development trend in future electric vehicle (EV) power supply technology due to its safety, flexibility, and convenience. With its industrialized development, interoperability has become an essential technical link. The interoperability of wireless charging systems refers to the ability of output performance to meet specified indicators when different transmitter and receiver devices are matched. This study reviews the research status of the interoperability of EV wireless charging technology. First, the definition and composition of the interoperability of wireless charging systems are briefly given. Then, the article provides a review of standards about interoperability so far. The interoperability of various magnetic couplers and compensation topologies is also analyzed and summarized. After that, the paper reviews the existing interoperability evaluation methods. Finally, this work highlights the existing problems and challenges in current research of interoperability. We hope that this work will contribute to the further development of EV wireless charging technology.

The development of a hydrogen energy-based society is becoming the solution for more and more countries. Fuel cell electric vehicles are the best carriers for developing a hydrogen energy-based society. The current research on hydrogen leakage and the diffusion of fuel cell electric vehicles has been sufficient. However, the study of hydrogen safety has not reduced the safety concerns for society and government management departments, concerning the large-scale promotion of fuel cell electric vehicles. Hydrogen safety is both a technical and psychological issue. This paper aims to provide a comprehensive overview of fuel cell electric vehicles’ hydrogen dispersion and the burning behavior and introduce the relevant work of international standardization and global technical regulations. The CFD simulations in tunnels, underground car parks, and multistory car parks show that the hydrogen escape performance is excellent. At the same time, the research verifies that the flow, the direction of leakage, and the vehicle itself are the most critical factors affecting hydrogen distribution. The impact of the leakage location and leakage pore size is much smaller. The relevant studies also show that the risk is still controllable even if the hydrogen leakage rate is increased ten times the limit of GTR 13 to 1000 NL/min and then ignited. Multi-vehicle combustion tests of fuel cell electric vehicles showed that adjacent vehicles were not ignited by the hydrogen. This shows that as long as the appropriate measures are taken, the risk of a hydrogen leak or the combustion of fuel cell electric vehicles is controllable. The introduction of relevant standards and regulations also indirectly proves this point. This paper will provide product design guidelines for R&D personnel, offer the latest knowledge and guidance to the regulatory agencies, and increase the public’s acceptance of fuel cell electric vehicles.

There are mainly two sedimentary types of the 2nd member of Jurassic Sangonghe Formation (J1s2) in the Qianshao area: shallow-water delta and sandy debris flow. In order to accurately understand the characteristics and further identify the difference of sedimentary microfacies, the characteristics of the grain size curve are analyzed. The results show that the cumulative probability curve of sandstone particle size in the research area mainly includes two basic types: tractive current type and sandy debris flow type. The tractive current type is mainly developed in the shallow-water delta front. Among them, the inner front subaqueous distributary channel microfacies develop two patterns: tri-segment pattern and one bouncing segment-one suspension segment-one complex transitional zone pattern. The transitional section is widely developed. There are two patterns in the subaqueous distributary channel microfacies of the outer front (bi-segment pattern and one bouncing segment-one suspension segment-one transitional zone pattern) and two patterns in the estuary bar microfacies (bi-bouncing segment-one suspension segment-one transitional zone pattern and one bouncing segment-one suspension segment-one transitional zone pattern). The main tractive current characteristics are higher bouncing component content and slope and lower suspended component content. The sand debris flow type mainly develops two patterns: one bouncing segment-one suspension segment-one transitional zone pattern and one bouncing segment-one suspension segment-one complex transitional zone pattern with lower jump component content and slope and higher suspended component content.

In the development of actual vehicles, manufacturers usually adopt a simplified control strategy to ensure the reliability of the control strategy based on the application scenarios. There are two main working modes for the fuel cell system in fuel cell electric vehicles in China. One is the stepped power type, and the other is the following power type. Therefore, the analysis and comparison of these two typical working modes in the power test of fuel cell electric vehicles helps determine how the fuel cell system works in the actual vehicle and how to choose energy management strategies in different application scenarios. We do the actual tests to explore how the two typical control strategies perform in actual vehicles. These two typical control strategies show different characteristics in the same test. It shows that the energy management strategies should be adopted according to the application scenarios and optimization goals. In the stepped power control strategy, the fluctuation of the fuel cell system and the frequency of starting and stopping are significantly reduced, which is beneficial to the durability of the fuel cell system. Compared with the stepped control strategy, the fluctuation of the output power of fuel cell electric vehicles with the following power control strategy increased significantly. At the same time, a simplified state of charge (SOC) test method is proposed. Due to the particularity of the stepped power control strategy, the change of capacity can be used to replace the change of SOC. For the following power control strategy, the change of electric energy can be used instead of SOC changes.

Free amino acids in the phloem sap are the dominant nitrogen source for aphids, but their availability is usually poor. Although some studies have explored the effect of dietary amino acid restriction on aphid performance, little is known about the molecular basis of these effects. Here, we examined the performance and transcriptome of the green peach aphid, Myzus persicae, fed a standard diet (Control diet) or a diet containing 50% of the total amino acids of the Control diet (Half diet). Aphid weight and fecundity were significantly reduced in the Half diet group. Transcriptomic analysis showed that a total of 1460 genes were differentially expressed between the groups were fed on the two diets, which many of them were associated with nutrient and energy metabolism. When feeding on the Half diet, aphids upregulated genes associated with the amino acid biosynthetic pathway (predominantly amino acid biosynthesis genes and some amino acid transporter genes) as well as the cysteine and serine protease genes. Furthermore, these aphids displayed increased expression of genes associated with glycolysis, which could generate intermediates for de novo amino acid biosynthesis. Consistent with this, elevated glucose levels were observed in aphids in the Half diet group. Additionally, the expression levels of several genes associated with hormonal signaling pathway were altered. Several genes related to juvenile hormone and insulin-like peptide (ILP) signaling were downregulated, including Krüppel homolog 1 (Kr-h1) and insulin-like peptide 5 (Ilp5), respectively. In contrast, several genes related to ecdysone signaling were upregulated including broad-complex core protein (Br-c) and shade (Shd). Despite their poor performances, M. persicae adapted to dietary restriction of amino acids, through upregulation of genes involved in amino acid biosynthesis, glycolysis, and protein degradation, as well as by altering the expression level of genes involved in hormone signaling pathways.

Benzoxazinoids are important secondary metabolites in gramineae plants and have inhibitory and toxic effects against a wide range of herbivore pests. However, the relationship between benzoxazinoid level and plant resistance to aphids remains controversial. In this study, we investigated the relationship between benzoxazinoids composition and concentration in wheat leaves and the resistance to the grain aphid Sitobion avenae. Overall, six benzoxazinoids were detected and identified by mass spectrometry based metabolites profiling, including three lactams, two hydroxamic acids, and one methyl derivative. The constitutive levels of these benzoxazinoids were significantly different among the wheat varieties/lines. However, none of these benzoxazinoids exhibited considerable correlation with aphid resistance. S. avenae feeding elevated the level of 2-O-β-D-glucopyranosyloxy-4,7-dimethoxy-(2H)-1,4-benzoxazin-3(4H)-one (HDMBOA-Glc) and reduced the level of 2-O-β-D-glucopyranosyloxy-4-hydroxy-7-(2H)-methoxy-1,4-benzoxazin-3(4H)-one (DIMBOA-Glc) in some of the wheat varieties/lines. Moreover, aphid-induced level of DIMBOA-Glc was positively related with callose deposition, which was closely associated with aphid resistance. Wheat leaves infiltrated with DIMBOA-Glc caused a noticeable increase of callose deposition and the effect was in a dose dependent manner. This study suggests that the constitutive level of benzoxazinoids has limited impact on S. avenae. Aphid feeding can affect the balance of benzoxazinoids metabolism and the dynamic level of benzoxazinoids can act as a signal of callose deposition for S. avenae resistance. This study will extend our understanding of aphid–wheat interaction and provides new insights in aphid-resistance wheat breeding.

Mud-caking of the cutterhead in a tunnel boring machine (TBM) has been commonly encountered when a TBM is excavating through strongly weathered rock or clay. Not only the opening of cutterhead could be blocked to cause problem for muck flowing through, mud-caking of a cutterhead will also lead to the increase of thrust and torque, as well as compromise of tunneling efficiency. To predict the mud-caking status in real time, a prediction model was established based on cutter temperature characteristics, and a bus-based detection system was designed to monitor cutter wear and temperature in tunneling. Such prediction model and detection system were verified on an earth pressure balance (EPB) TBM at a Shenzhen metro project. The research demonstrated that the detection system performed its function of monitoring cutter wear and temperature changes in real time. A dynamic prediction of cutterhead mud-caking status was also proved using the prediction model.

Elements’ diffusion between Ti-6Al-4V alloy and Al in the process of sliding was investigated from 400 °C to 600 °C. The results showed that the atoms were diffused at the Ti-6Al-4V/Al interface. When sliding at 400 °C and 500 °C, no intermetallic compound was detected on the surface of Ti-6Al-4V alloy. When sliding at 600 °C, intermetallic TiAl3 was formed and grew on the surface of Ti-6Al-4V alloy. The diffusion thickness of Al atoms on the surface of Ti-6Al-4V alloy increased with increasing time and temperature. The diffusion kinetic equation of Al atoms on the surface of Ti-6Al-4V alloy was successfully established. The diffusion activation energy of Al atoms in the sliding process was calculated to be 28.22 kJ·mol−1 and the dynamic index n was 0.5. The diffusion growth of Al atoms was controlled by normal parabolic law with time.