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D2ANet:Difference-aware attention network for multi-level change detection from satellite imagery

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Computational Visual Media 2023年第3期9卷 563-579页

作者： Jie mei Yi-Bo Zheng Ming-Ming cheng TMCC CSNankai UniversityTianjin 300350China State Key Laboratory of Earth Surface Processes and Resource Ecology Faculty of Geographical ScienceBeijing Normal UniversityBeijing 100875China

Recognizing dynamic variations on the ground,especially changes caused by various natural disasters,is critical for assessing the severity of the damage and directing the disaster response.However,current workflows for disaster assessment usually require human analysts to observe and identify damaged buildings,which is labor-intensive and unsuitable for large-scale disaster areas.In this paper,we propose a difference-aware attention network(D2ANet)for simultaneous building localization and multi-level change detection from the dual-temporal satellite imagery.Considering the differences in different channels in the features of pre-and post-disaster images,we develop a dual-temporal aggregation module using paired features to excite change-sensitive channels of the features and learn the global change pattern.Since the nature of building damage caused by disasters is diverse in complex environments,we design a difference-attention module to exploit local correlations among the multi-level changes,which improves the ability to identify damage on different scales.Extensive experiments on the large-scale building damage assessment dataset xBD demonstrate that our approach provides new state-of-the-art results.Source code is publicly available at https://***/mj129/D2ANet.

关键词： change detection building localization sate-llite imagery dual-temporal aggregation difference attention

Non-linear Radical Additions-Coupling Polymerization of Monovinyl Monomers towards Polymer Networks: Theory, Tunability and Heritable Architecture

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Chinese Journal of Polymer Science 2022年第12期40卷 1623-1630,I0008页

作者： Li-mei Ren cheng-Lin Li Qi Wang MOE Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science&Engineering Zhejiang UniversityHangzhou 310027China Current address:Zhejiang University-University of Edinburgh Institute Zhejiang University School of Medicineand Key Laboratory of Tissue Engineering and Regenerative Medicine of Zhejiang ProvinceZhejiang University School of MedicineHangzhou 310027China

Exploring new polymerization strategy for current available monomers is a big challenge in polymer science. Here we re-investigate radical polymerization of monovinyl monomer(MVM) initiated by uniform branched polyfunctional initiator(PFI), which is termed non-linear radical additions-coupling polymerization(NLRAs CP). In NLRAs CP, both addition and coupling reactions of radical contribute to the construction of the polymer chains, which leads to continuous growth of branch topology. Theoretical analysis of NLRAs CP predicts that the gelation is determined by the functionality of PFI(a), the extent of initiation of the PFI(q) and the termination factor of radical(φ). NLRAs CPs of styrene and methyl methacrylate promoted by Cu(0)/MeTREN or Mn_(2)(CO)_(10)/visible light were conducted. After the cleavage of incorporated PFI fragment or junctions in the network, the network was transformed to linear chains having almost the same structure as segmental chains in the precursor network. This allows the reverse deducing the network structure from its cleaved products. It has been proven that NLRAs CP includes stepwise initiation of PFI, chain-growth of segmental chains and successive endlinking of macroradicals derived from PFI. The three parameters related to the gelation process, a, q and φ, were adjusted via binary PFI, the feed ratio of [Mn_(2)(CO)_(10)]/[PFI] and addition of non-homopolymerizable comonomer respectively. The minimum values of a and q, and the minimum amount of comonomer required for gelation were determined,which can be applied to estimate φ of various macroradicals. NLRAs CP opens a general and facile strategy for synthesis of a variety of polymer networks with heritable architecture by one-pot polymerization of various MVMs.

关键词： Non-linear radical additions-coupling polymerization Monovinyl monomer Polyfunctional initiator Polymer network Theory

Friction and wear behavior and mechanism of low carbon microalloyed steel containing Nb

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China Foundry 2023年第3期20卷 263-270页

作者： mei-yi Yuan Jia-cheng Zhang Yi-tao Yang School of Materials Science and Engineering Shanghai UniversityShanghai 200444China

Dry sliding friction and wear test of Nb containing low carbon microalloyed steel was carried out at room temperature,and the effect of Nb on the wear behavior of the steel,as welll as the mechanism was studied.Scanning electron microscopy(SEM) and energy dispersive spectrometry(EDS) were employed to analyze the morphology and composition of the worn surface,and the structure evolution of the plastic deformation layer.The carbide content and type in the steel were analyzed by the electrolytic extraction device and X-ray diffraction(XRD).The experimental results demonstrate that the addition of 0.2% Nb can refine the grain and generate Nb C to improve the wear resistance of the steel.By enhancing the load and speed of wear experiment,the wear mechanism of the test steel with 0.2% Nb changes from slight oxidation wear to severe adhesion wear and oxidation wear.Compared with the load,the increase in the rotation speed exerts a greater influence on the wear of the test steel.

关键词： Nb content low carbon microalloyed steel friction and wear carbide

Recent Advances in Asymmetric Transformations of Unactivated Alkanes and Cycloalkanes through Direct C—H Functionalization

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Chinese Journal of Chemistry 2022年第23期40卷 2825-2837,I0002页

作者： Shiyan cheng Qianyu Li Xiuliang cheng Yu-mei Lin Lei Gong Key Laboratoryof Chemical Biology of Fujian Province Collegeof Chemistry and Chemical EngineeringXiamen UniversityXiamen Fujian 361005China Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province(IKKEM) XiamenFujian 361005China

The direct conversion of unactivated alkanes and cycloalkanes into structurally diverse molecules through aliphatic C—H functionalization is a useful process, which has attracted intense interest from academia and industry. Methods to control chemo- and site-selectivity, combined with asymmetric catalysis, provide appealing access to high value-added enantiomer-enriched compounds but are far less developed. This review focuses on recent progress in (i) asymmetric reactions of alkanes or cycloalkanes with prochiral substrates which generate a stereocenter adjacent to the cleaved C(sp3)–H bond, and (ii) C(sp3)–H enantiodiscriminatory reactions creating a new stereogenic center on the carbon of a cleaved C(sp3)–H bond. Elegant strategies are discussed, including (a) metal carbene-induced C—H insertions by chiral rhodium catalysts, (b) metal-oxo-mediated C—H oxidation by biomimetic manganese catalysts, (c) enzyme catalysis by cytochromes P450 variants, and (d) dual catalysis by a photocatalyst and a chiral Lewis acid (CLA) or a chiral phosphoric acid (CPA). These catalytic systems can not only precisely recognize primary, secondary and tertiary C—H bonds at specific positions in alkanes and cycloalkanes, but also support a high level of stereoselectivity in the reactions. It is expected that the advances will stimulate further progress in asymmetric catalysis, synthetic methodology, pharmaceutical development and industrial processes.

关键词： Asymmetric catalysis C-H functionalization Alkane Site-selectivity Enantioselectivity

Effect of die structure parameters on deformation behavior of bent tube in free bending process

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Journal of Iron and Steel Research(International) 2023年第3期30卷 487-503页

作者： Wei Wang cheng cheng Li Wan Jie Tao Xun-zhong Guo Chun-mei Liu College of Material Science and Technology Nanjing University of Aeronautics and AstronauticsNanjing 211100JiangsuChina State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074HubeiChina Capital Aerospace Machinery Corporation Beijing 100076China

The bending section of tube between the bending die and the guider is in a less constrained state during the free bending process.The free bending dies have the important impact on the plastic deformation behavior and the forming quality of tube.To study the evolution law of the deformation behavior of tube with the die structure parameters and optimize the free bending die parameters,the free bending experiments and the corresponding numerical simulations were carried out.The design principle of free bending die was illustrated.The free bending experiment was conducted to verify the reliability of the numerical simulation method.Based on the numerical simulation results,the influence of the distance between the center point of bending die and the front end of guider on the forming quality of bent tube is more obvious than that of the fillet of guider.However,the fillet of bending die hardly affects the stress and strain distribution and the evolution of the wall thickness.Finally,the free bending experiments with the newly determined free bending dies were conducted.The ultimate bending radius of bent tube is reduced and the forming quality is improved.

关键词： Free bending Die structure parameter Forming quality Numerical simulation Tube

Dynamics of the intestinal bacterial community in black soldier fly larval guts and its influence on insect growth and development

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Insect Science 2023年第4期30卷 947-963页

作者： Xin-Yu Li Cheng mei Xing-Yu Luo Dilinuer Wulamu Shuai Zhan Yong-Ping Huang Hong Yang Hubei Key Laboratory of Genetic Regulation and Integrative Biology Institute of EntomologySchool of Life SciencesCentral China Normal UniversityWuhanChina CAS Key Laboratory of Insect Developmental and Evolutionary Biology CAS Center for Excellence in Molecular Plant SciencesInstitute of Plant Physiology and EcologyShanghai Institutes for Biological SciencesChinese Academy of SciencesShanghaiChina

Black soldier fly(BSF),Hermetia illucens(Diptera:Stratiomyidae),is a promi-nent insect for the bioconversion of various organic wastes.As a saprotrophic insect,the BSF inhabits microbe-rich environments.However,the influences of the intestinal mi-croorganisms on BSF growth and development are not very clear.In this study,the dy-namics of the intestinal bacterial community of BSF larvae(BSFL)were analyzed using pyrosequencing.Actinobacteria,Bacteroidetes,Firmicutes,and Proteobacteria were the most prevalent bacterial phyla in the intestines of all larval instars.The dynamic changes in bacterial community compositions among different larval instars were striking at the genus level.Klebsiella,Clostridium,Providencia,and Dysgonomonas were the relatively most abundant bacteria in the 1st-to 4th-instar BSFL,respectively.Dysgonomonas and Providencia also dominated the 5th-and 6th-instar larvae,at ratios of 31.1%and 47.2%,respectively.In total,148 bacterial strains affiliated with 20 genera were isolated on differ-ent media under aerobic and anaerobic conditions.Among them,6 bacteria,BSF1-BSF6,were selected for further study.The inoculation of the 6 isolates independently into germ-free BSFL feeding on an artificial diet showed that all the bacteria,except BSF4,sig-nificantly promoted BSF growth and development compared with the germ-free control.Citrobacter,Dysgonomonas,Klebsiella,Ochrobactrum,and Providencia promoted BSF development significantly by increasing the weight gains of larvae and pupae,as well as increasing the prepupae and eclosion rates.In addition,Citrobacter,Klebsiella and Prov-idencia shortened the BSF life cycle significantly.The results illustrate the promotive effects of intestinal bacteria on BSF growth and development.

关键词： bacterial isolates germ-free BSF larvae growth and development Hermetia illucens promotive effects

Laparoscopic liver resection for hepatocellular carcinoma complicated with significant portal hypertension:A propensity score-matched survival analysis

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Hepatobiliary & Pancreatic Diseases International 2023年第4期22卷 358-365页

作者： Zhang-You Guo Yuan Hong Bing Tu Yao cheng Xiao-mei Wang Department of Minimally Invasive Interventional Therapy Yunnan Cancer HospitalThe Third Affiliated Hospital of Kunming Medical UniversityYunnan Cancer CenterKunming 650118China Medical Laboratory The First Affiliated Hospital of Kunming Medical UniversityInstitute of Experimental Diagnostics of Yunnan ProvinceKey Laboratory of Laboratory Medicine of Yunnan ProvinceKunming 650032China Department of Hepatobiliary Surgery The Second Affiliated HospitalChongqing Medical UniversityChongqing 400010China

Background: Significant portal hypertension(SPH) is a relative contraindication for patients with resectable hepatocellular carcinoma(HCC). However, increasing evidence indicates that liver resection is feasible for HCC patients with SPH. Methods: HCC patients with cirrhosis who underwent laparoscopic liver resection(LLR) in two centers from January 2013 to April 2018 were included. Surgical and survival outcomes were analyzed to explore potential prognostic factors. Propensity score matching(PSM) analysis was performed to minimize bias. Results: A total of 165 patients were divided into two groups based on the presence(SPH, n = 76) or absence(non-SPH, n = 89) of SPH. Patients in the SPH group had longer operative time, more blood loss, and more advanced TNM stage than patients in the non-SPH group( P 0.05). After PSM, alpha-fetoprotein(AFP) ≥ 400 μg/L [hazard ratio(HR) = 4.71, 95% confidence interval(CI): 2.69-8.25], ascites(HR = 2.18, 95% CI: 1.30-3.66), American Society of Anesthesiologists(ASA) classification(Ⅲ vs. Ⅱ)(HR = 2.13, 95% CI: 1.11-4.07) and tumor diameter > 5 cm(HR = 3.91, 95% CI: 2.02-7.56) independently predicted worse OS. Conclusions: LLR for patients with HCC complicated with SPH appears feasible at the price of increasing operative time and blood loss. AFP, ascites, ASA classification and tumor diameter may predict the prognosis of HCC complicated with SPH after LLR.

关键词： Hepatocellular carcinoma Significant portal hypertension Laparoscopic liver resection Propensity score matching analysis

High-lift siphon flow velocity in a 4-mm siphon hose

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2017年第6期18卷 487-495页

作者： Cheng mei Xu LIANG Hong-yue SUN Meng-ping WU Ocean College Zhejiang University Hangzhou 310058 China

High-lift siphon drainage by 4-mm internal diameter siphon hoses is a real-time, free-power, and long-term approach for slope drainage. The conventional hydraulics formula for pressurized pipe flow is generally used to calculate the single-phase velocity of siphon flow. However, an intensive cavitation phenomenon occurs in the high-lift siphon hose and then a two-phase flow is formed. Research on the velocity of high-lift siphon flow is a prerequisite for the application of siphon drainage with a 4-mm siphon hose. Few investigations of this subject have been carried out. Hence, experiments on the high-lift (8 m≤H 0≤10.3 m) siphon drainage in a 4-mm siphon hose were performed. The characteristics of siphon flow under different conditions were observed and test data were obtained. Comparisons between test results and calculated results showed that significant errors were given by the hydraulics formula. It is demonstrated that the effect of gas in a siphon hose should be included in the calculation of flow velocity. The findings can be used to determine the number of siphon hoses and layout of siphon drainage holes, and provide valuable information for geotechnical companies.

关键词： Siphon flow velocity High-lift siphon Elevation difference Water lift Gas effect 虹吸流速高扬程虹吸高程差扬程气体影响 TU42

ROS-mediated BNIP3-dependent mitophagy promotes coelomocyte survival in Apostichopus japonicus in response to Vibrio splendidus infection

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Zoological Research 2022年第2期43卷 285-300页

作者： Lian-Lian Sun Yi-Na Shao mei-Xiang You cheng-Hua Li State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products Ningbo UniversityNingboZhejiang 315211China Laboratory for Marine Fisheries Science and Food Production Processes Qingdao National Laboratory for Marine Science and TechnologyQingdaoShandong 266071China State-Province Joint Laboratory of Marine Biotechnology and Engineering Ningbo UniversityNingboZhejiang 315211China

Organisms produce high levels of reactive oxygen species(ROS)to kill pathogens or act as signaling molecules to induce immune responses;however,excessive ROS can result in cell death.To maintain ROS balance and cell survival,mitophagy selectively eliminates damaged mitochondria via mitophagy receptors in vertebrates.In marine invertebrates,however,mitophagy and its functions remain largely unknown.In the current study,Vibrio splendidus infection damaged mitochondrial morphology in coelomocytes and reduced mitochondrial membrane potential(ΔΨm)and mitophagosome formation.The colocalization of mitochondria and lysosomes further confirmed that lipopolysaccharide(LPS)treatment increased mitophagy flux.To explore the regulatory mechanism of mitophagy,we cloned Bcl2/adenovirus E1 B 19 kDa protein-interacting protein 3(BNIP3),a common mitophagy receptor,from sea cucumber Apostichopus japonicus(Aj BNIP3)and confirmed that Aj BNIP3 was significantly induced and accumulated in mitochondria after V.splendidus infection and LPS exposure.At the mitochondrial membrane,Aj BNIP3 interacts with microtubule-associated protein 1 light chain 3(LC3)on phagophore membranes to mediate mitophagy.After Aj BNIP3 interference,mitophagy flux decreased significantly.Furthermore,Aj BNIP3-mediated mitophagy was activated by ROS following the addition of exogenous hydrogen peroxide(H2 O2),ROS scavengers,and ROS inhibitors.Finally,inhibition of BNIP3-mediated mitophagy by Aj BNIP3 small interfering RNA(si RNA)or high concentrations of lactate increased apoptosis and decreased coelomocyte survival.These findings highlight the essential role of Aj BNIP3 in damaged mitochondrial degradation during mitophagy.This mitophagy activity is required for coelomocyte survival in A.japonicus against V.splendidus infection.

关键词： Apostichopus japonicus Mitophagy Bcl2/adenovirus E1B 19 kDa protein-interacting protein 3 Reactive oxygen species Microtubule-associated protein 1 light chain 3