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The processes that formed the ultra-large and high-grade Kaiyang phosphate deposit, which is located in Guizhou Province, China, remain unclear. Here, we present the results of a petrological and mineralogical investigation of the compact and white lamination-bearing phosphorite within the deposit. These white lamination-bearing phosphorites contain many silicified collophane breccias that are surrounded by collophane cements. Electron probe microanalysis indicates that the phosphorite within the deposit is enriched in P2O5, SiO2, K2O, and Al2O3 and is depleted in FeO, F, MgO, SO3, and Na2O compared with the more common clastic phosphorite rocks. In addition, the coated-grain phosphorite located beneath this layer contains a cement that was gravitationally transported and was formed by leaching. These new data indicate that the deposit represents a crust formed as a result of palaeo-weathering. The widespread presence of this type of phosphatic rock in the Kaiyang area indicates that palaeo-weathering played a key role in the formation of the phosphorite deposits in this region.

Microwave sintering is regarded as a high-efficiency, energy-saving, and rapid-heating technique for the preparation of structural materials on the Moon. However, the influencing factors (i...

Aluminum(Al)/ammonium perchlorate(AP)/hydroxyl-terminated polybutadiene (HTPB) propellant is the most widely used propulsion system currently. Its ignition and combustion processes are fairly complex and need to be better understood. In this study, the thermal decomposition, ignition, and combustion properties of an Al/AP/HTPB propellant were investigated using a thermogravimetry–differential scanning calorimetry and a laser ignition testing system. The morphology and size distribution of the condensed combustion products (CCPs) were analyzed using a laser particle size analyzer and scanning electron microscopy. Results showed that the thermal decomposition process of the propellant consisted of three stages. The first stage (100–430 °C) was a major mass loss stage and exhibited typical features of AP decomposition. The second stage (430–630 °C) was mainly accompanied by the decomposition of remaining HTPB as well as slight oxidation of Al particles. In the third stage, further oxidation of Al particles resulted in a small mass increase. Due to the continuous emission problem, only a few combustion intermediates were identified in the combustion emission spectrum curves. The propellant combustion process could be roughly divided into three stages, and the flame development stage lasted longer than the flame decline stage. As the pressure increased, the propellant ignition delay time decreased and the burning rate increased significantly. The effect of pressure on ignition delay was more pronounced at low pressures. The CCPs consisted of three types. The oxidation of Al particles in the propellant followed the diffusion reaction mechanism. Agglomerates appeared in several different morphologies and had relatively low combustion efficiency under experimental conditions. A 2-D pocket-like structure was observed on the propellant surface.

Lunar breccias preserve the records of geologic processes on the Moon. In this study, we report the occurrence, petrography, mineralogy, and geological significance of the observed secondary olivine veinlets in lunar feldspathic breccia meteorite Northwest Africa (NWA) 11273. Bulk-rock composition measurements shown that this meteorite is geochemically similar to other lunar highland meteorites. In NWA 11273, five clasts are observed to host veinlets that are dominated by interconnecting olivine mineral grains. The host clasts mainly composed of mafic minerals (i.e., pyroxene and olivine) and probably sourced from a basaltic lithology. The studied olivine veinlets (~5 to 30 μm in width) are distributed within the mafic-mineral host, but do not extend into the adjacent plagioclase. Chemically, these olivine veinlets are Fe-richer (Fo41.4–51.9), compared with other olivine grains (Fo54.3–83.1) in lithic clasts and matrix of NWA 11273. By analogy with the secondary olivine veinlets observed in meteorites from asteroid Vesta (HED-group samples) and lunar mare samples, our study suggests that the newly observed olivine veinlets in NWA 11273 are likely formed by secondary deposition from a lunar fluid, rather than by crystallization from a high-temperature silicate melt. Such fluid could be sulfur- and phosphorous-poor and likely had an endogenic origin on the Moon. The new occurrence of secondary olivine veinlets in breccia NWA 11273 reveals that the fluid mobility and deposition could be a previously underappreciated geological process on the Moon.

Laboratory experiments have shown that thermal gradients in silicate melts can lead to isotopic fractionation; this is known as the Richter effect. However, it is perplexing that the Richter effect has not been documented in natural samples as thermal gradients commonly exist within natural igneous systems. To resolve this discrepancy, theoretical analysis and calculations were undertaken. We found that the Richter effect, commonly seen in experiments with wholly molten silicates, cannot be applied to natural systems because natural igneous samples are more likely to be formed out of partially molten magma and the presence of minerals adds complexity to the behaviour of the isotope. In this study, we consider two related diffusion-rate kinetic isotope effects that originate from chemical diffusion, which are absent from experiments with wholly molten samples. We performed detailed calculations for magnesium isotopes, and the results indicated that the Richter effect for magnesium isotopes is buffered by kinetic isotope effects and the total value of magnesium isotope fractionation can be zero or even undetectable. Our study provides a new understanding of isotopic behaviour during the processes of cooling and solidification in natural magmatic systems.

To distinguish secondary craters from primary craters is very important in lunar studies that involve such tasks as dating the lunar surface and investigating the meteoritic flux. However, this is usually difficult since distant secondary craters generally have an appearance similar to primary ones. Bart and Melosh, 2007a , Bart and Melosh, 2007b proposed a method to distinguish the two types of craters based on the relationship between the crater diameter (D) and the size of the largest boulder (B) around the crater: B=KD2/3, where K is the fitting coefficient. They concluded that secondary craters have a 60% larger fitting coefficient (K) than primary craters. However, because of the poor quality of the available data and an insufficient number of crater samples, their results need further substantiation, as they have suggested. This research aims to examine their results with recently obtained very high resolution data and many more sampled craters. Our results indicate that the criterion proposed by Bart and Melosh, 2007a , Bart and Melosh, 2007b is actually not applicable, i.e., the fitted coefficient (K), in cases of primary and secondary craters, cannot be confidently distinguished.

The catalytic effects of four industrial wastes, namely, the soap residue (SR), brine sludge (BS), calcium carbide residue (CCR), and white lime mud (WLM), on coal thermal ignition were investigated. The acidity of palmitate anion associated with Na+ in SR was lower than that of chloride anion combined with Na+ in BS, which resulted in an improved the combustion of SR. The acidity of OH− anion combined with Ca2+ in CCR was lower than that of CO32− anion combined with Ca2+ in WLM, resulting in CCR exhibiting a better catalytic effect on coal ignition. The alkaline metal Na had lower initial ionisation energy than the alkaline earth metal Ca. Therefore, the Na-rich SR exhibited higher catalytic activity on coal ignition than Ca-rich CCR. The ignition temperature of coal with 0.5% SR decreased from 544 to 503 °C.

Pediatric cough is a heterogeneous condition in terms of symptoms and the underlying disease mechanisms. Symptom phenotypes hold complicated interactions between each other to form an intricate network structure. This study aims to investigate whether the network structure of pediatric cough symptoms is associated with the prognosis and outcome of patients. A total of 384 cases were derived from the electronic medical records of a highly experienced traditional Chinese medicine (TCM) physician. The data were divided into two groups according to the therapeutic effect, namely, an invalid group (group A with 40 cases of poor efficacy) and a valid group (group B with 344 cases of good efficacy). Several well-established analysis methods, namely, statistical test, correlation analysis, and complex network analysis, were used to analyze the data. This study reports that symptom networks of patients with pediatric cough are related to the effectiveness of treatment: a dense network of symptoms is associated with great difficulty in treatment. Interventions with the most different symptoms in the symptom network may have improved therapeutic effects.

Nanofluid fuels are promising fuels in the fields of spaceflight and aviation. Their stability is a critical constraint for potential applications. Oleic acid can enhance the stability of nanofluid...

Experiments and molecular dynamics (MD) simulations were conducted to investigate the effect of ammonia nitrogen and low-molecular-weight organics on the adsorption of sodium lignosulfonate (SL) on Shenhua coal. Results of adsorption and adsorption film thickness experiments showed that ammonia nitrogen and low-molecular-weight organics have different effects on the adsorption of SL on coal surface, thus resulting in different adsorption configurations of SL. A ternary system that was composed of water–SL–Shenhua coal was established through MD simulation. The adsorption mechanism of SL on Shenhua coal in different solutions was explored, and the influencing factors were analyzed using a microscopic mechanism. Results showed that the adsorption conformations of SL molecules on coal surface in aqueous and low-molecular-weight organics solutions are single-layer and multi-point adsorption, whereas the adsorption conformations in ammonia nitrogen solutions are double-layer adsorption. The mechanism of the adsorption of SL molecule on Shenhua coal surface by ammonia nitrogen and low-molecular-weight organics was studied in detail. The calculation results of adsorption energy are consistent with the experimental results in thermodynamics. This result demonstrates the feasibility and accuracy of the MD simulation.

Mining industries worldwide have inevitably resorted to exploiting resources from the deep underground. However, traditional mining methods can cause various problems, e.g., considerable mining difficulty, environmental degradations, and frequent disastrous accidents. To exploit deep resources in the future, the concept of mining must be reconsidered and innovative new theories, methods, and technologies must be applied. To effectively acquire coal resources deeper than 2000 m, new theoretical and technological concepts about deep in situ fluidized mining are required. The limits of mining depth need to be broken to acquire deep-coal resources in an environmentally friendly, safe, and efficient manner. This is characterized by ‘There are no coal on the ground and no men in the coal mine’. First, this paper systematically explains deep in situ fluidized coal mining. Then, it presents a new theoretical concept, including the theories of mining-induced rock mechanics, three-field visualization, multi-physics coupling for in situ transformation, and in situ mining, transformation and transport. It also presents key technological concepts, including those of intelligent, unmanned, and fluidized mining. Finally, this paper presents a strategic roadmap for deep in situ fluidized coal mining. In summary, this paper develops new theoretical and technological systems for accomplishing groundbreaking innovations in mining technologies of coal resources in the deep underground.

Ultrahigh-strength concrete (UHSC) is a promising material for engineering applications, owing to the rapid increase of compressive strength at early ages. In this study, the creep behaviour of UHSC with an ultralow water/binder ratio (= 0·16) under loading at early ages was investigated. The influence factors of loading age (1, 2, 3 and 7 d), normal coarse aggregate and steel fibre content (0, 1 and 2%) were taken into consideration. Experiment results showed that the addition of coarse aggregates and ultrafine steel fibres were obviously effective in decreasing the creep deformation of UHSC but that the specific creep of UHSC with 2% steel fibres was higher than that of UHSC with 1% steel fibres. Specimens loaded at earlier ages had higher creep. At a microscopic level, it could be seen that the creep of UHSC was influenced by hydration products and concrete internal defects. From a macroscopic perspective, it could be seen that this was the result of a combination of strength and elastic modulus development factors. By introducing a coordination factor for the development of strength and elastic modulus, a modified creep model was proposed to predict the creep of UHSC.

Organic wastewater can be used to prepare coal water slurry (CWS) for the resource utilization of organic wastewater. The components in organic wastewater are highly complex, and some of their subs...

The hydrogen generation performance of the mixture of aluminum powder and sodium borohydride was investigated experimentally in steam atmosphere to reveal the promotion effects and mechanis...

The newly discovered Baogudi gold district is located in the southwestern Guizhou Province, China, where there are numerous Carlin-type gold deposits. To better understand the geological and geochemical characteristics of the Baogudi gold district, we carried out petrographic observations, elemental analyses, and fluid inclusion and isotopic composition studies. We also compared the results with those of typical Carlin-type gold deposits in southwestern Guizhou. Three mineralization stages, namely, the sedimentation diagenesis, hydrothermal (main-ore and late-ore substages), and supergene stages, were identified based on field and petrographic observations. The main-ore and late-ore stages correspond to Au and Sb mineralization, respectively, which are similar to typical Carlin-type mineralization. The mass transfer associated with alteration and mineralization shows that a significant amount of Au, As, Sb, Hg, Tl, Mo, and S were added to mineralized rocks during the main-ore stage. Remarkably, arsenic, Sb, and S were added to the mineralized rocks during the late-ore stage. Element migration indicates that the sulfidation process was responsible for ore formation. Four types of fluid inclusions were identified in ore-related quartz and fluorite. The main-ore stage fluids are characterized by an H2O–NaCl–CO2–CH4 ± N2 system, with medium to low temperatures (180–260 °C) and low salinity (0–9.08% NaCl equivalent). The late-ore stage fluids featured H2O–NaCl ± CO2 ± CH4, with low temperature (120–200 °C) and low salinity (0–7.48% NaCl equivalent). The temperature, salinity, and CO2 and CH4 concentrations of ore-forming fluids decreased from the main-ore stage to the late-ore stage. The calculated δ13C, δD, and δ18O values of the ore-forming fluids range from − 14.3 to − 7.0‰, −76 to −55.7‰, and 4.5–15.0‰, respectively. Late-ore-stage stibnite had δ34S values ranging from − 0.6 to 1.9‰. These stable isotopic compositions indicate that the ore-forming fluids originated mainly from deep magmatic hydrothermal fluids, with minor contributions from strata. Collectively, the Baogudi metallogenic district has geological and geochemical characteristics that are typical of Carlin-type gold deposits in southwest Guizhou. It is likely that the Baogudi gold district, together with other Carlin-type gold deposits in southwestern Guizhou, was formed in response to a single widespread metallogenic event.

Phosphorite of the Ediacaran Doushantuo Formation accumulated in the central Guizhou province during the Neoproterozoic-Cambrian Phosphogenic Event, producing the first true phosphorite giant in Earth history. Deposition is interpreted to have occurred on a wave-dominated epeiric platform along the northern margin of the Qianzhong Uplift. Lithofacies stacking patterns and two paleokarst surfaces record phosphogenesis through at least two sea-level cycles. As in younger Phanerozoic epeiric sea phosphorites, the delivery of upwelled phosphorus is interpreted to have stimulated phosphogenesis in a range of shallow-water environments. Ten phosphatic and associated lithofacies are recognized in the Doushantuo Formation. Wavy and horizontal laminated pristine facies were the locus of phosphogenesis and reflect the authigenic precipitation of francolite in accumulating fine sediment. Granular, cross-stratified phosphorite is interpreted to have been produced through storm-wave winnowing of pristine facies and the subsequent transport, redeposition, and concentration of phosphatic peloids into economic beds. Beds with the highest concentration of phosphorus formed in shallow, wave-agitated environments around paleo-topographic highs. Paragenetic analysis suggests that secondary meteoric processes further enriched the phosphorus content (>35 wt%) of these granular beds during sea-level lowstands. Such aerially extensive, upwelling-related phosphorite contrasts Paleoproterozoic and Neoproterozoic phosphatic deposits. Throughout much the Proterozoic francolite precipitation was restricted to shallow-water, photosynthetic oxygen oases where redox sensitive phosphogenic processes were focused in the sediment. The Doushantuo Formation is interpreted to record the oxygenation of the water column and concomitant expansion of phosphogenic environments during the Neoproterozoic Oxygenation Event. This progressive ventilation of the deep ocean forever changed the biogeochemical cycling of phosphorus in the marine realm and set the stage for the deposition of phosphorite giants that punctuate the Phanerozoic stratigraphic record.

A novel pocket connection was put forward to be utilized in both ends of a precast bridge column to connect cap beam and foundation, respectively. The pocket connection adopted noncontact lap-spliced bars and ultra-high performance concrete (UHPC) grout. One 1:2.5 scale specimen was fabricated and tested to investigate the seismic performance of the precast bridge column with the proposed pocket connections. Based on OpenSees platform, a verified finite element model was utilized to simulate cyclic behavior of a monolithic reinforced concrete companion. The comparison was carried out to evaluate the precast bridge column in a comprehensive way. The results show that drift capacities of the two bridge columns are up to 5% and controlled by lateral force degradation. The lapped length of five times diameter is feasible when UHPC grout is used for longitudinal bars with a diameter no more than 32 mm. For the precast bridge column, the joint opening between column and foundation contributes over 30% to total lateral displacement and traditional equivalent plastic hinge model may be not suitable. With drift ratio over 1.5%, the precast specimen has larger secant stiffness than that of the monolithic companion, owing to the shorter shear length of the precast specimen caused by moving up of the actual plastic hinge region. The precast and monolithic bridge columns have good energy dissipation capacity, and the maximum damping ratios reach up to 19.8% and 22.6% at 5% drift ratio, respectively. The precast specimen has 18.8% less residual drift ratio at 5% drift ratio than the monolithic companion.

The study focusing on the combustion of flowing aluminum particles and the properties of condensed phase products has important guiding significance for the practical application of aluminum-based propellants. Based upon an in-house built dynamic combustion experimental system, the dynamic combustion process of aluminum particles and the properties of condensed phase products under different atmospheres were studied in detail. The microstructure, size distribution and active aluminum content of samples were analyzed by field emission scanning electron microscopy, laser particle analyzer and inductively coupled plasma atomic emission spectroscopy. By monitoring the temperature distribution at different points in the furnace, the heat release of the samples at different positions is approximated, and the combustion efficiency is calculated. In the atmosphere containing CO2, the maximum combustion efficiency can reach the value of 94.41%, followed by that in H2O atmosphere, which had the value of 81.19%. Finally, under the N2 containing atmosphere, the combustion is the weakest, and has the value of only 53.91%, confirming that the combustion followed the following descending order: CO2 > H2O > N2. The condensed phase products were mainly composed of agglomerates formed by the aggregation of particles and alumina smoke. It is well known that the reaction of the sample in the furnace not only follows the melt-dispersion mechanism, but also the diffusion mechanism. The high-speed camera captured four typical combustion forms of aluminum particles during flow, which are stable combustion, release of alumina smoke, crushing and extinction. The average burning time of four stages were studied. The two reaction mechanisms occurring under the same reaction conditions are determined by the nature of aluminum particles themselves.

Aluminum (Al) nanoparticles were coated with ammonium perchlorate (AP) to obtain AP-coated Al nanoparticles with different coating amounts. The coating layers were characterized by TEM and TG. Resu...

A stability analyser and a rheometer were used to study the effects of Tween 85 (polyoxyethylene sorbitan trioleate) on the dispersion properties of nano-aluminium/JP-10 (exo-tetrahydrodicyclopentadiene) suspensions. Results show that the addition of Tween 85 can effectively improve the stability of two-phase suspensions by hindering particle aggregation and reduce the viscosity of a system. The surface characteristics of the zeta potential and the contact angle were measured. The dispersion of the suspensions was improved by Tween 85 mainly by enhancing the steric hindrance of particles. The adsorbed particles obtained in JP-10 with different Tween 85 concentrations were analysed via scanning electron microscopy and Fourier transform infrared spectroscopy to explore the adsorption behaviour of Tween 85 molecules on the surface of aluminium particles and to confirm that Tween 85 formed an adsorption layer on the particle surface. Thermogravimetric analysis indicated that the adsorption amount of Tween 85 increased with its concentration in JP-10. The roughness analysis of the surface of adsorbed particles was measured via atomic force microscopy to characterise the thickness of the adsorption layer. The results showed that Tween 85 molecules formed an irregular adsorption layer on the particle surface, and an increase in the concentration of Tween 85 in JP-10 increased the thickness of the adsorption layer.

Aluminum (Al) powder agglomeration is one of the main reasons for the degradation in the performance of aluminized solid propellant rockets and so, understanding the combustion behavior of aluminum in solid propellants is of great importance. In this work, a laser ignition test bench was used to study the behavior of Al on the burning surface of an aluminum/ammonium perchlorate/hydroxyl-terminated polybutadiene composite propellant, under atmospheric pressure. Based on the images captured by a high-speed camera, the agglomeration process and behavior of the agglomerates were analyzed in detail. The size distribution and speed of motion of the agglomerates away from the burning surface were also considered. Results show that the formation of an agglomerate on the burning surface from multiple aluminum particles include three stages: accumulation, aggregation, and agglomeration. Local ignition promotes the collapse of the aggregate into a spherical agglomerate. Before detachment, the agglomerates often roll around on the burning surface and pick up more aluminum, promoting self-growth. The interesting phenomenon of an agglomerate droplet rupturing and ejecting liquid alumina on the burning surface was clearly captured for the first time. This is believed to indicate the heterogeneous composition characteristics of the agglomerate. The transformation of the polar oxide cap on one part of the agglomerate surface into an alumina shell that fully covers the droplet surface was also captured for the first time. The agglomerates have different shapes, diameters, and velocities when they leave the burning surface. The formation of non-spherical agglomerates consisting of more than one aluminum droplet is ascribed to the propellant microstructure. The 400 agglomerates that were counted had diameters that ranged from 51 μm to 815 μm and the majority of them (nearly 98%) were below 400 μm. The velocities of motion of 176 agglomerates exhibited great dispersion, with the maximum and minimum velocity being 196 cm/s and 13 cm/s, respectively. In general, the moving velocities of the agglomerates decreased with increasing diameter.

Geological disasters induce coal mine accidents, which usually cause casualties and large economic losses in coal mines. However, the chain relationship and disaster mechanisms of geological disasters secondary coal mine accidents are still unclear, and the research on risk assessment methods of geological disasters induced coal mine accidents is relatively scarce. Based on investigating typical cases of secondary coal mine accidents caused by different types of geological disasters, this paper analyzed and studied the disaster-causing factors and chain generation relationship of geological disaster secondary coal mine accidents and studied the disaster-causing mechanism of secondary coal mine accidents caused by geological disasters. On the basis of analyzing the influencing factors of geological disaster secondary coal mine accidents, the risk index system of geological disaster secondary coal mine accidents was constructed, the risk grade assessment method was studied. The risk assessment model of geological disaster secondary coal mine accidents was constructed, and the weight of each index in the assessment system was determined by using the analytic hierarchy process, and the normalized treatment was carried out. According to the safety risk index of geological disaster secondary coal mine accidents, the grade division was carried out to guide the targeted prevention and control measures.

Land management using suitable thinning intensities can promote the yield of Moso bamboo (Phyllostachys edulis) forests and alter the nutrient content and stoichiometric characteristics within the soil. However, the effects of different thinning intensities on soil carbon (C), nitrogen (N), and phosphorus (P) stoichiometry of P. edulis forests have not been comprehensively studied. Here, we evaluated the effects of three thinning intensities—no thinning control (NT), moderate thinning (annual removal of 15% of mature bamboo, MT), and heavy thinning (annual removal of 33% of mature bamboo, IT)—on the soil organic C (SOC), total N (TN), and total P (TP) stocks and their stoichiometry characteristics of a P. edulis forest located in the subtropical zone. The results showed that SOC, TN, and TP stocks decreased with increasing soil depth after three years of thinning. The SOC, TN, and TP stocks and the ecological stoichiometry ratios were varied with the change of thinning intensity and SOC stocks declining with the increased thinning intensity, but TN and TP stocks for the MT treatment were enhanced. The order of TN and TP stocks was MT > NT > IT. In comparison to CK, TN and TP stocks for MT increased significantly by 18.8 and 37.3%, while SOC, TN, and TP stocks for IT decreased by 31.0%, 7.2%, and 21.4%, respectively. The C:N and C:P ratios of MT decreased by 32.8% and 39.0%, and those of IT decreased by 26.5% and 15.6%, respectively. In summary, we conclude that the MT is an effective management strategy to promote soil nutrient cycling and provides a reference for formulating management strategies in subtropical Moso bamboo forests.

An urban metro network is susceptible to becoming vulnerable and difficult to recover quickly in the face of an unexpected attack on account of the system’s complexity and the threat of various emergencies. Therefore, it is necessary to assess the resilience of urban metro networks. However, the research on resilience assessment of urban metro networks is still in the development stage, and it is better to conduct said research using a technique which combines many attributes, multiple methods, and several cases. Therefore, based on the complex network modeling and topological characteristics analysis of metro systems, a metro network’s robustness and vulnerability measurement method under node interruption and edge failure is proposed for the first time in this study. Then, considering the three cases of general station interruption, interchange station interruption, and traffic tunnel failure, a quantitative resilience assessment model of metro networks is put forward, and the corresponding recovery strategies are discussed. Finally, a case study of the Zhengzhou Metro Network (ZZMN) under an extreme rainstorm is conducted to demonstrate the viability of the proposed model. The results show that ZZMN possesses scale-free and small-world network properties, and it is robust to random interruptions but vulnerable to deliberate attacks. ZZMN still needs to improve its effectiveness in information transmission. The centrality distribution for each node in the ZZMN network differs significantly, and each node’s failure has a unique impact on the network. The larger the DC, BC, and PR of a node is, the lower the network’s robustness after its removal is, and the stronger the vulnerability is. Compared with the three cases of general station interruption, interchange station interruption, and traffic tunnel failure, the network loss caused by tunnel failure was the lowest, followed by general station interruption, and the interruption at interchange stations was the most costly. Given the failures under various cases, the metro management department should prioritize selecting the optimal recovery strategy to improve the resilience of the metro network system. This study’s findings can assist in making urban metro systems less vulnerable to emergencies and more resilient for a quick recovery, which can provide scientific theoretical guidance and decision support for the safety and resilient, sustainable development of urban metro systems.

Recently, cargo ship detection in remote sensing images based on deep learning is of great significance for cargo ship monitoring. However, the existing detection network is not only unable to realize autonomous operation on spaceborne platforms due to the limitation of computing and storage, but the detection result also lacks the directional information of the cargo ship. In order to address the above problems, we propose a novel cargo ship detection and directional discrimination method for remote sensing images based on a lightweight network. Specifically, we design an efficient and lightweight feature extraction network called the one-shot aggregation and depthwise separable network (OSADSNet), which is inspired by one-shot feature aggregation modules and depthwise separable convolutions. Additionally, we combine the RPN with the K-Mean++ algorithm to obtain the K-RPN, which can produce a more suitable region proposal for cargo ship detection. Furthermore, without introducing extra parameters, the directional discrimination of the cargo ship is transformed into a classification task, and the directional discrimination is completed when the detection task is completed. Experiments on a self-built remote sensing image cargo ship dataset indicate that our model can provide relatively accurate and fast detection for cargo ships (mAP of 91.96% and prediction time of 46 ms per image) and discriminate the directions (north, east, south, and west) of cargo ships, with fewer parameters (model size of 110 MB), which is more suitable for autonomous operation on spaceborne platforms. Therefore, the proposed method can meet the needs of cargo ship detection and directional discrimination in remote sensing images on spaceborne platforms.

Fuzzing is a technique widely used in vulnerability detection. The process usually involves writing effective fuzz driver programs, which, when done manually, can be extremely labor intensive. Previous attempts at automation leave much to be desired, in either degree of automation or quality of output. In this paper, we propose IntelliGen, a framework that constructs valid fuzz drivers automatically. First, IntelliGen determines a set of entry functions and evaluates their respective chance of exhibiting a vulnerability. Then, IntelliGen generates fuzz drivers for the entry functions through hierarchical parameter replacement and type inference. We implemented IntelliGen and evaluated its effectiveness on real-world programs selected from the Android Open-Source Project, Google's fuzzer-testsuite and industrial collaborators. IntelliGen covered on average 1.08X-2.03X more basic blocks and 1.36X-2.06X more paths over state-of-the-art fuzz driver synthesizers FUDGE and FuzzGen. IntelliGen performed on par with manually written drivers and found 10 more bugs.

The cold chain safety of vaccines is a global issue. The electronic vaccine vial monitor (eVVM) label can monitor the temperature of vaccines in real time and provide "early warning" prompts. In order to comprehensively evaluate the monitoring efficiency of eVVM, this study selected 75 eVVM labels and distributed them with a total of 600 vaccine vial monitor (VVM) labels of four different types in different experimental environment (2-8℃, -20℃ and 40℃), and used a temperature recorder as "gold standard". The results showed that the accuracy of the eVVM labels and VVM labels in high temperature environment was as same as that of the temperature recorder (疫苗的冷链安全为全球性问题，电子疫苗热敏感标签（eVVM）可对疫苗温度进行实时监控，并进行“预警”提示。为综合评价 eVVM 的监测效能，本研究在不同产品批次中随机抽取 75 个 eVVM 标签，将其与四种不同类型共 600 个疫苗温度指示标签（VVM）平均分配到不同的实验环境中（2～8℃、−20℃ 以及 40℃），采用温度记录仪作为对照。结果显示，eVVM 标签、VVM 标签在高温温度监测方面的精确度与温度记录仪具有很好的一致性（