Showing papers by "Long Wang published in 2022"
TL;DR: In this paper , a bottom-up strategy to exploit the heterogeneous phase interface to enable high corrosion durability is proposed, which results in superior corrosion resistance with an outstanding strength-ductility balance of the composites via ultrafine-grained and precipitation strengthening.
Abstract: The antagonism between strength and corrosion resistance in graphene‐reinforced aluminum matrix composites is an inherent challenge to designing reliable structural components. Heteroatom microstructural modification is highly appreciated to conquer the obstacle. Here, a bottom‐up strategy to exploit the heterogeneous phase interface to enable high corrosion durability is proposed. Deformation‐driven metallurgy derived from severe plastic deformation is developed to produce Mg‐alloyed fluorinated graphene structures with homogeneous dispersion. These structures allow for absorbing corrosion products, forming a dense protective layer against corrosion, and local micro‐tuning of the suppression of charge transfer. This results in superior corrosion resistance with an outstanding strength‐ductility balance of the composites via ultrafine‐grained and precipitation strengthening. The anti‐corrosion polarization resistance remains 89% of the initial state after 2‐month immersion in chloride‐containing environment, while the ultra‐tensile strength and elongation of 532 ± 39 MPa and 17.3 ± 1.2% are obtained. The economical strategy of heteroatom modification broadens the horizon for anti‐corrosion engineering in aluminum matrix composites, which is critical for the design of carbonaceous nanomaterial‐reinforced composites to realize desired performances for practical applications.
32 citations
13 citations
TL;DR: In this article , the authors used metagenomic analysis of 15 sediment samples from the Mariana Trench to discover 3,206 viral scaffolds with high diversity and novelty, including some Phycodnaviridae and jumbo phages.
Abstract: The Mariana Trench harbors a substantial number of infective viral particles. However, very little is known about the identity, survival strategy, and potential functions of viruses in the trench sediments. ABSTRACT Viruses are ubiquitous in the oceans. Even in the deep sediments of the Mariana Trench, viruses have high productivity. However, little is known about their species composition and survival strategies in that environment. Here, we uncovered novel viral communities (3,206 viral scaffolds) in the upper slope sediments of the Mariana Trench via metagenomic analysis of 15 sediment samples. Most (99%) of the viral scaffolds lack known viral homologs, and ca. 59% of the high-quality viral genomes (total of 111 with completeness of >90%) represent novel genera, including some Phycodnaviridae and jumbo phages. These viruses contain various auxiliary metabolic genes (AMGs) potentially involved in organic carbon degradation, inorganic carbon fixation, denitrification, and assimilatory sulfate reduction, etc. This study provides novel insight into the almost unknown benthic viral communities in the Mariana Trench. IMPORTANCE The Mariana Trench harbors a substantial number of infective viral particles. However, very little is known about the identity, survival strategy, and potential functions of viruses in the trench sediments. Here, through metagenomic analysis, unusual benthic viral communities with high diversity and novelty were discovered. Among them, 59% of the viruses with a genome completeness of >90% represent novel genera. Various auxiliary metabolic genes carried by these viruses reflect the potential adaptive characteristics of viruses in this extreme environment and the biogeochemical cycles that they may participate in. This study gives us a deeper understanding of the peculiarities of viral communities in deep-sea/hadal sediments.
12 citations
TL;DR: In this article , seven new compounds were identified from a marine-derived fungus, Talaromyces mangshanicus BTBU20211089, which was isolated from a sediment sample collected from the South China Sea.
Abstract: Seven new compounds, namely talaromanloid A (1), talaromydene (2), 10-hydroxy-8-demethyltalaromydine and 11-hydroxy-8-demethyltalaromydine (3 and 4), talaromylectone (5), and ditalaromylectones A and B (6 and 7), together with seven known compounds were identified from a marine-derived fungus, Talaromyces mangshanicus BTBU20211089, which was isolated from a sediment sample collected from the South China Sea. Their chemical structures were determined using spectroscopic data, including HRESIMS, 1D, and 2D NMR techniques. The absolute configurations of 1 and 2 were elucidated by comparing experimental and calculated ECD spectra. Compounds 1, 2, 6, and 7 are new compounds possessing a novel carbon skeleton. Compound 6 is a dimeric molecule of 3 and 9. Compound 7 shared a unique structure of the cyclized dimer of 3 and 4. All the compounds were tested for their bioactivities against Staphylococcus aureus, Escherichia coli, and Candida albicans.
9 citations
TL;DR: In this article , the effects of different gradients obtained by the two pins on the weld formation, microstructure, and mechanical properties were compared, and the results indicated that the large-tip pin increases heat input and material flow at the bottom, reducing the gradient along the thickness.
Abstract: The temperature and material flow gradients along the thick section of the weld seriously affect the welding efficiency of friction stir welding in medium-thick plates. Here, the effects of different gradients obtained by the two pins on the weld formation, microstructure, and mechanical properties were compared. The results indicated that the large-tip pin increases heat input and material flow at the bottom, reducing the gradient along the thickness. The large-tip pin increases the welding speed of defect-free joints from 100 mm/min to 500 mm/min compared to the small-tip pin. The ultimate tensile strength and elongation of the joint reached 247 MPa and 8.7%, equal to 80% and 65% of the base metal, respectively. Therefore, reducing the temperature and material flow gradients along the thickness by designing the pin structure is proved to be the key to improving the welding efficiency for thick plates.
7 citations
TL;DR: In this article , an ingenious nano-micro SiC-reinforced Al matrix composite (AMC) with heterogeneous grain structures of coarse and fine grains was designed via a novel deformation-driven metallurgy method.
Abstract: Strength-ductility trade-off dilemma remains a significant obstacle to high-strength composites due to the undesirable dislocation storability. Herein, an ingenious nano-micro SiC-reinforced Al matrix composite (AMC) with heterogeneous grain structures of coarse and fine grains was designed via a novel deformation-driven metallurgy method. The accumulated geometrically necessary dislocations and the intragranularly dispersed SiC particles were tailored based on the principle of back stress amelioration, which was a key point to maintain the dynamic balance with the applied stress toward strength-ductility synergy. The ultimate tensile strength and uniform elongation of the designed SiC5np-5µp/Al composite reached 324 MPa and 12.9%, respectively, and the strength was 181% as high as that of the SiC10µp/Al with only 3% ductility loss. As such, a new strategy was provided herein to promote strength-ductility synergy via the further modified back stress.
6 citations
6 citations
TL;DR: In this article , the authors studied the geometry of the strategy space of all admissible zero-determinant strategies in prisoner's dilemma games and showed that the class of equalizers forming a hyperplane is the critical equilibrium manifold, only part of which is stable.
Abstract: The advent of zero-determinant (ZD) strategies has reshaped the study of reciprocity and cooperation in the iterated prisoner’s dilemma games. The ramification of ZD strategies has been demonstrated through their ability to unilaterally enforce a linear relationship between their own average payoff and that of their co-player. Common practice conveniently represents this relationship by a straight line in the parametric plot of pairwise payoffs. Yet little attention has been paid to studying the actual geometry of the strategy space of all admissible ZD strategies. Here, our work offers intuitive geometric relationships between different classes of ZD strategies as well as nontrivial geometric interpretations of their specific parameterizations. Adaptive dynamics of ZD strategies further reveals the unforeseen connection between general ZD strategies and the so-called equalizers that can set any co-player’s payoff to a fixed value. We show that the class of equalizers forming a hyperplane is the critical equilibrium manifold, only part of which is stable. The same hyperplane is also a separatrix of the cooperation-enhancing region where the optimum response is to increase cooperation for each of the four payoff outcomes. Our results shed light on the simple but elegant geometry of ZD strategies that is previously overlooked.
5 citations
TL;DR: In this paper , grain boundary engineering is employed to regulate the distribution of the Ta element and enhance the density of LLZTO by introducing the La2O3 additive, while the residual La 2O3 nanoparticles fill up void defects.
Abstract: Solid-state lithium batteries (SSLBs) based on Ta-doped Li6.5La3Zr1.5Ta0.5O12 (LLZTO) suffer from lithium dendrite growth, which hinders their practical application. Herein, first principles simulations indicate that the Ta element prefers to segregate along grain boundaries in the form of Ta2O5 precipitates due to a high energy difference induced by Ta doping. Grain boundary engineering is employed to regulate the distribution of the Ta element and enhance the density of LLZTO by introducing the La2O3 additive. The sufficient La2O3 additive reacts with the Ta2O5 precipitates, while the residual La2O3 nanoparticles fill up void defects, promoting the homogeneous distribution of the Ta element and improving the relative density to ∼98%. Critical current density of the symmetric Li battery reaches 2.12 mA·cm-2 at room temperature with the solid-state electrolyte (LLZTO + 5 wt % La2O3), which increases by 41% compared to pure LLZTO. SSLBs with the LiFePO4 cathode achieve a stable cycling performance with a discharge capacity of 138.6 mA·h·g-1 after 400 cycles at 0.2 C. This work provides theoretical insights into the distribution of Ta-doped LLZTO and inhibits lithium dendrite growth through grain boundary engineering.
5 citations
TL;DR: Li et al. as mentioned in this paper proposed a semantic segmentation and counting network to improve the segmentation accuracy and counting efficiency of pigs in complex image segmentation, which can effectively improve the level of fine management of pig farms.
Abstract: Accurate identification and intelligent counting of pig herds can effectively improve the level of fine management of pig farms. A semantic segmentation and counting network was proposed in this study to improve the segmentation accuracy and counting efficiency of pigs in complex image segmentation. In this study, we built our own datasets of pigs under different scenarios, and set three levels of number detection difficulty—namely, lightweight, middleweight, and heavyweight. First, an image segmentation model of a small sample of pigs was established based on the DeepLab V3+ deep learning method to reduce the training cost and obtain initial features. Second, a lightweight attention mechanism was introduced, and attention modules based on rows and columns can accelerate the efficiency of feature calculation and reduce the problem of excessive parameters and feature redundancy caused by network depth. Third, a recursive cascade method was used to optimize the fusion of high- and low-frequency features for mining potential semantic information. Finally, the improved model was integrated to build a graphical platform for the accurate counting of pigs. Compared with FCNNs, U-Net, SegNet, and DenseNet methods, the DeepLab V3+ experimental results show that the values of the comprehensive evaluation indices P, R, AP, F1-score, and MIoU of LA-DeepLab V3+ (single tag) are higher than those of other semantic segmentation models, at 86.04%, 75.06%, 78.67%, 0.8, and 76.31%, respectively. The P, AP, and MIoU values of LA-DeepLab V3+ (multiple tags) are also higher than those of other models, at 88.36%, 76.75%, and 74.62%, respectively. The segmentation accuracy of pig images with simple backgrounds reaches 99%. The pressure test of the counting network can calculate the number of pigs with a maximum of 50, which meets the requirements of free-range breeding in standard piggeries. The model has strong generalization ability in pig herd detection under different scenarios, which can serve as a reference for intelligent pig farm management and animal life research.
TL;DR: In this paper , a root-enhanced friction stir welding from aspects of the on-demand distribution of heat input and plastic deformation through an enlarged-tip pin was proposed.
TL;DR: In this article , the submerged friction stir welding (SFSW) was employed to decrease the peak temperature of the joint and control the thermal gradient of the thickness direction, which were beneficial in suppressing the coarsening of the intermetallic compounds (IMCs) layer and improving the weld formation.
Abstract: The medium-thick Al/Mg dissimilar friction stir welding (FSW) joint has serious groove and cavity defects due to uneven thermal distribution in the thickness direction. The submerged friction stir welding (SFSW) was employed to decrease the peak temperature of the joint and control the thermal gradient of the thickness direction, which were beneficial in suppressing the coarsening of the intermetallic compounds (IMCs) layer and improving the weld formation. According to the SEM results, the thickness value of the IMC layer in the nugget zone and shoulder affect zone decreased from 0.78 μm and 1.31 μm in FSW process to 0.59 μm and 1.21 μm in SFSW process at the same parameter, respectively. Compared with the FSW process, SFSW improves the thermal accumulation during the process, which inhibits the formation of the IMCs and facilitates the material flow to form a mechanical interlocking structure. This firm interface formation elevates the effective contact area of the whole joint interface and provides a strong connection between the dissimilar metals. Thus, the ultimate strength of the 6 mm thick Al/Mg dissimilar SFSW joints was enhanced to 171 MPa, equivalent to 71.3% of AZ31B Mg alloys strength.
TL;DR: Wang et al. as mentioned in this paper reported seesaw-like patterns in spatial variations of precipitation Hg in Western China, based on Hg speciation measurements at nine stations over this remote region.
01 Jan 2022
TL;DR: In this paper , the benefits of friction-based joining techniques are elucidated so that these methods may be better exploited and industrialized, which can simultaneously realize the mechanical and chemical bonding between polymer and metal, improving the mechanical performances of hybrid joints.
Abstract: The hybrid structures between polymer (or polymer matrix composites) and metal (aluminum alloy) have become the effective ways to produce the lighter, safer and more environment friendly vehicles for the manufacturing fields of automotive and aerospace. The state-of-the-art friction-based welding techniques, such as friction stir welding (FSW), friction spot joining (FSpJ), friction lap welding (FLW) or friction stir lap welding (FSLW), Friction self-riveting welding (FSRW), are characterized by low peak temperature, severe plastic deformation, energy efficiency and non-pollution, which can simultaneously realize the mechanical and chemical bonding between polymer and metal, improving the mechanical performances of hybrid joints. The purpose of this chapter is to elucidate the benefits of friction-based joining techniques so that these methods may be better exploited and industrialized.
TL;DR: In this article , deformation-driven processing was proposed to prepare carbon nanotube (CNTs)-reinforced polyether-ether-ketone (PEEK) matrix composites with enhancement in wear resistance.
Abstract: Despite wide applications in mechanical transmission components, sparked with extraordinary wear resistance, polymeric composites face the challenges of reinforcement agglomeration. In this work, deformation-driven processing was proposed to prepare carbon nanotube (CNTs)-reinforced poly-ether-ether-ketone (PEEK) matrix composites with enhancement in wear resistance. Severe plastic deformation contributed to the homogeneous dispersion of the reinforcements without undesirable agglomeration. Low frictional heat input ensured the structural integrity of CNTs. The coefficient of friction and wear rate of 3.0 wt.% CNTs/PEEK were, respectively, 7.32% and 6.71% lower than those of pure PEEK. This strategy provides a high-efficiency approach to preparing high wear-resistance polymeric composites, attributed to its self-heating, low-cost, and high-performance characteristics.
TL;DR: Results show that by applying the attention encoder structure, ResNet-50 can improve the accuracy of chicken age detection to 95.2%, superior to other current ones.
Abstract: Simple Summary Most management methods for poultry farming currently rely on human labor. Such management is labor-intensive and inefficient, especially in identifying poultry growth stages. Given the lack of a high-precision artificial method for chick’s day-age detection, a high-performance day-age classification and detection model for chicks was proposed based on artificial intelligent techniques. This method can detect and classify chicks in six different living stages from 1 to 32 day-ages, and the accuracy is 95.2%, superior to other current ones. In order to apply this method in practical scenarios, it has been deployed into an application based on the IOS system, which can recoganize the day-age of chicks by capturing real-time photos. The system is currently deployed in Rizhao City, Shandong Province, China. It helps chicken farm staff automatically detect the behavior of chickens, whose excellent working effect proves the robust availibility of the proposed method. Abstract Thanks to the boom of computer vision techniques and artificial intelligence algorithms, it is more available to achieve artificial rearing for animals in real production scenarios. Improving the accuracy of chicken day-age detection is one of the instances, which is of great importance for chicken rearing. To solve this problem, we proposed an attention encoder structure to extract chicken image features, trying to improve the detection accuracy. To cope with the imbalance of the dataset, various data enhancement schemes such as Cutout, CutMix, and MixUp were proposed to verify the effectiveness of the proposed attention encoder. This paper put the structure into various mainstream CNN networks for comparison and multiple ablation experiments. The final experimental results show that by applying the attention encoder structure, ResNet-50 can improve the accuracy of chicken age detection to 95.2%. Finally, this paper also designed a complete image acquisition system for chicken houses and a detection application configured for mobile devices.
TL;DR: In this paper , a novel hybrid process, Expanding-Welding method (EW), was proposed to achieve ultra-strong joint performance and high processing efficiency of joining dissimilar metals.
TL;DR: In this paper , the authors investigated whether social influence improves the collective wisdom of a crowd or undermines it, based on a naive learning setting in influence systems theory, and provided various conditions for improving, optimizing and undermining the crowd accuracy.
Abstract: A long-standing debate is whether social influence improves the collective wisdom of a crowd or undermines it. This paper addresses this question based on a naive learning setting in influence systems theory: in our models individuals evolve their estimates of an unknown truth according to the weighted-average opinion dynamics. A formal mathematization is provided with rigorous theoretical analysis. We obtain various conditions for improving, optimizing and undermining the crowd accuracy, respectively. We prove that if the wisdom of finite-size group is improved, then the collective estimate converges to the truth as group size increases, provided individuals' variances are finite. We show that whether social influence improves or undermines the wisdom is determined by the social power allocation of the influence system: if the influence system allocates relatively larger social power to relatively more accurate individuals, it improves the wisdom; on the contrary, if the influence system assigns less social power to more accurate individuals, it undermines the wisdom. At a population level, individuals' susceptibilities to interpersonal influence and network centralities are both crucial. To improve the wisdom, more accurate individuals should be less susceptible and have larger network centralities. Particularly, in democratic influence networks, if relatively more accurate individuals are relatively less susceptible, the wisdom is improved; if more accurate individuals are more susceptible, the wisdom is undermined, which is consistent with the reported empirical evidence. Our investigation provides a theoretical framework for understanding the role social influence plays in the emergence of collective wisdom.
TL;DR: During a survey of culturable fungi in the coastal areas of China, three new species of Penicillium sect.
Abstract: During a survey of culturable fungi in the coastal areas of China, three new species of Penicillium sect. Lanata-Divaricata were discovered and studied with a polyphasic taxonomic approach, and then named as P. donggangicum sp. nov. (ex-type AS3.15900T = LN5H1-4), P. hepuense sp. nov. (ex-type AS3.16039T = TT2-4X3, AS3.16040 = TT2-6X3) and P. jiaozhouwanicum sp. nov. (ex-type AS3.16038T = 0801H2-2, AS3.16207 = ZZ2-9-3). In morphology, P. donggangicum is unique in showing light yellow sclerotia and mycelium, sparse sporulation, restricted growth at 37 °C, irregular conidiophores, intercalary phialides and metulae, and pyriform to subspherical conidia. P. hepuense is distinguished by the fast growth on CYA and YES and slow growth on MEA at 25 °C, weak or absence of growth at 37 °C, biverticillate and monoverticillate penicilli, and ellipsoidal conidia. P. jiaozhouwanicum is characterized by abundant grayish-green conidia en masse and moderate growth at 37 °C, the appressed biverticillate penicilli and fusiform, smooth-walled conidia. These three novelties were further confirmed by the phylogenetic analyses based on either the combined BenA-CaM-Rpb2 or the individual BenA, CaM, Rpb2 and internal transcribed spacer (ITS) sequences.
TL;DR: In this article , a double-pin friction stir welding (DPFSW) joint was proposed to solve the problem of difficult weld formation with a large depth to width ratio (DWR).
TL;DR: Chrysanthemum neo-oreastrum (Asteraceae, Anthemideae) has been placed in synonymy with C. hypargyreum as mentioned in this paper .
Abstract: Chrysanthemum neo-oreastrum (Asteraceae, Anthemideae) has been placed in synonymy with C. hypargyreum. Based on our examination of herbarium specimens and field investigation, C. neo-oreastrum was found to be easily distinguishable from C. hypargyreum morphologically. Its independent specific status is therefore resurrected. An emended description and a distribution map are also provided for this species.
17 Sep 2022
TL;DR: In this article , the authors established a theoretical framework to address evolutionary dynamics of spatial games under strong selection and proved that the evolutionary process soon or later either enters a cycle and from then on repeats the cycle periodically, or stabilizes at some state almost everywhere.
Abstract: We establish a theoretical framework to address evolutionary dynamics of spatial games under strong selection. As the selection intensity tends to infinity, strategy competition unfolds in the deterministic way of winners taking all. We rigorously prove that the evolutionary process soon or later either enters a cycle and from then on repeats the cycle periodically, or stabilizes at some state almost everywhere. This conclusion holds for any population graph and a large class of finite games. This framework suffices to reveal the underlying mathematical rationale for the kaleidoscopic cooperation of Nowak and May’s pioneering work on spatial games: highly symmetric starting configuration causes a very long transient phase covering a large number of extremely beautiful spatial patterns. For all starting configurations, spatial patterns transit definitely over generations, so cooperators and defectors persist definitely. This framework can be extended to explore games including the snowdrift game, the public goods games (with or without loner, punishment), and re-peated games on graphs. Aspiration dynamics can also be fully addressed
TL;DR: Ligulariamonocephala is a remarkable new species from Hubei, China that is readily distinguishable in the whole genus by character combination of the reniform to cordate-reniform leaf blades which are palmately-pinnately veined and abaxially purplish red.
Abstract: Abstract Ligulariamonocephala, a remarkable new species from Hubei, China, is described and illustrated. It is readily distinguishable in the whole genus by character combination of the reniform to cordate-reniform leaf blades which are palmately-pinnately veined and abaxially purplish red, the solitary and erect capitula, and the pappus which are as long as or slightly longer than tube of the tubular corolla. A detailed description and distribution map of the species are also presented herein.
17 Oct 2022
TL;DR: In this paper , the authors introduce a general framework of repeated optional multiplayer games, where individuals can freely opt out of each interaction and resume participation later, and they find that optional participation significantly enhances the cooperation rate, promoting both the emergence and maintenance of cooperation.
Abstract: In repeated social interactions, humans often have the freedom to opt out and be absent due to unpleasant experiences or low benefits. Yet most studies on direct reciprocity neglect this option of opting out and implicitly assume that repeated interactions are compulsory. Here, we introduce a general framework of repeated optional multiplayer games, where individuals can freely opt out of each interaction and resume participation later. We find that optional participation significantly enhances the cooperation rate, promoting both the emergence and maintenance of cooperation. It acts as a catalyst for the emergence of cooperation by helping escape from the social trap of mutual defection and it sustains cooperation by posing more threats to intentional defectors. Furthermore, we analytically identify two novel classes of strategies that readily become equilibria and contribute to such promotive effects. Our work thus highlights that voluntary participation plays a crucial role in the evolution of cooperation in repeated interactions.
TL;DR: Artemisia nortonii (Asteraceae, Anthemideae) from Dinggyê county in Xizang (Tibet), China, was reported in this paper .
Abstract: Rediscovery of Artemisia nortonii (Asteraceae, Anthemideae) from Dinggyê county in Xizang (Tibet), China, is reported. The type locality of A. nortonii is determined to be Tingri in southwestern Xizang, a county closely neighboring with Dinggyê, not Gyaca county in southeastern Xizang. Consultation of literature and survey of herbarium specimens indicate that this species is currently known only from Dinggyê and Tingri in the Mount Everest (Zhu Mu Lang Ma Feng) region in southwestern Xizang, not occurring in eastern and southern Xizang as previously recorded. A full morphological description, a distribution map, and color photographs are provided for A. nortonii.