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Mechanical performance of 22SiMn2TiB steel welded with lowtransformation- temperature filler wire and stainless steel filler wire

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Journal of Iron and Steel Research(International) 2024年第4期31卷 967-981页

作者： Zi-dong Lin Kai-jie Song zhen Sun Zi-qian Zhu Xue-feng zhao Constantinos Goulas Wei ya Xing-hua Yu School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China Beijing Institute of Technology Chongqing Innovation Center Chongqing 401120China Department of Design Production and Management Faculty of Engineering Technology.University of TwenteEnschede 7500 AETheNetherlands Rotterdam Additive Manufacture Fieldlab(RAMLAB) Rotterdam 3089 JWTheNetherlands

TX-80 low-transformation-temperature(LTT)welding wire was used to replace the traditional ER 307Si welding wire to realize the connection of 22SiMn2TiB armor steel in manual overlay welding.The previously existing issues,such as welding cracks,large welding deformation,and severe welding residual stress,were solved to ensure good strength and ductility requirements.In particular,with the same welding conditions,TX-80 LTT wire eliminates welding cracks.It reduces the welding deformation no matter the base pretreatment of pre-setting angle or no pre-setting angle.By comparison,it was found that the microstructure at the TX-80 weld is mainly composed of martensite and a small amount of retained austenite.In contrast,the microstructure of the ER 307Si weld consists of a large amount of austenite and a small amount of skeleton-like ferrite.The variation trend of residual stress and microhardness from the weld to the base were investigated and compared with the mechanical properties of base materials.The TX-80 and the ER 307Si tensile samples elongation is 6.76%and 6.01%,while the ultimate tensile strengths are 877 and 667 MPa,respectively.The average impact toughness at room temperature of the ER 307Si weld is 143.9 J/cm^(2),much higher than that of the TX-80 weld,which is only 36.7 J/cm^(2).The relationship between impact and tensile properties with microstructure species and distribution was established.In addition,the fracture surface of the tensile and the impact samples was observed and analyzed.Deeper dimples,fewer pores,larger radiation zone,and shear lips of TX-80 samples indicate better tensile ductility and worse impact toughness than those of ER 307Si weld.

关键词： Low-transformation-temperature material 22SiMn2TiB steel Welding deformation Residual stress Martensitic transformation Mechanical property

Gastric ectopic pancreas combined with synchronous multiple early gastric cancer: A rare case report

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World Journal of Clinical Cases 2023年第7期11卷 1569-1575页

作者： zhen-ya zhao Yue-Xing Lai Ping Xu Department of Gastroenterology Songjiang Hospital Affiliated to Shanghai Jiaotong University School of Medicine(Preparatory Stage)Shanghai 201600China

BACKGROUND A large percentage of patients with ectopic pancreas are asymptomatic.When present,the symptoms are typically non-specific.These lesions are predominantly located in the stomach and benign in nature.Synchronous multiple early gastric cancer(SMEGC)(two or more simultaneous malignant lesions with early gastric cancer)is relatively rare and particularly easy to overlook during endoscopic examination.The prognosis of SMEGC is generally poor.We report a rare case of ectopic pancreas with concomitant SMEGC.CASE SUMMARY A 74-year-old woman presented with paroxysmal upper abdominal pain.On initial investigations,she tested positive for Helicobacter pylori(H.pylori).She underwent esophagogastroduodenoscopy which revealed a 1.5 cm×2 cm major lesion at the greater curvature and a 1 cm minor lesion at the lesser curvature of the stomach.On endoscopic ultrasound,the major lesion showed hypoechoic changes,uneven internal echoes and unclear boundaries between some areas and the muscularis propria.Endoscopic submucosal dissection was performed to excise the minor lesion.A laparoscopic resection was chosen for the major lesion.On histopathological examination,the major lesion contained high grade intraepithelial neoplasia with a small focus of cancer.A separate underlying ectopic pancreas was found under this lesion.The minor lesion contained high grade intraepithelial neoplasia.In this case,the patient was diagnosed with SMEGC with concomitant ectopic pancreas in the stomach.CONCLUSION Patients with atrophy,H.pylori,and other risk factors should be carefully investigated to avoid missing other lesions including SMEGC and ectopic pancreas.

关键词： Synchronous multiple early gastric cancer Ectopic pancreas Pathology Case report

A Denoiser for Correlated Noise Channel Decoding: Gated-Neural Network

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China Communications 2024年第2期21卷 122-128页

作者： Xiao Li Ling zhao zhen Dai Yonggang Lei School of Electronic and Information Engineering Beihang UniversityBeijing 100191China Beijing Institute of Tracking and Telecommunications Technology BITTT

This letter proposes a sliced-gated-convolutional neural network with belief propagation(SGCNN-BP) architecture for decoding long codes under correlated noise. The basic idea of SGCNNBP is using Neural Networks(NN) to transform the correlated noise into white noise, setting up the optimal condition for a standard BP decoder that takes the output from the NN. A gate-controlled neuron is used to regulate information flow and an optional operation—slicing is adopted to reduce parameters and lower training complexity. Simulation results show that SGCNN-BP has much better performance(with the largest gap being 5dB improvement) than a single BP decoder and achieves a nearly 1dB improvement compared to Fully Convolutional Networks(FCN).

关键词： belief propagation channel decoding correlated noise neural network

On a Flexible Loan Repayment Method Depending on Borrower's Asset with an Early Termination Clause

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Acta Mathematicae Applicatae Sinica 2024年第2期40卷 557-567页

作者： Jin LIANG Jia-qi MAO zhao-ya LIU School of Mathematical Sciences Tongji UniversityShanghai 200092China

Aiming at the problem that the asset’s fluctuation influences the borrower’s repayment ability,a loan with a new and flexible repayment method is designed,which depends on the asset value of the borrower.The repayment method can reduce the loan default probability,but it causes the uncertainty of the pay off time.Because the repayment term is related to the regular repayment amount in this method,a boundary for the regular repayment amount is set up in order to avoid too long repayment term.This will balance the benefit of borrowers and lenders and improve the applicability of this method.By establishing a mathematical model of the residual value of the loan,this model can be transformed into an initial-boundary problem of a partial differential equation.The analytic solution and the expected time to pay off the loan are obtained.Finally,numerical analysis are shown.

关键词： flexible repayment method repayment ratio early termination clause expected pay off time

Differential Evolution Hemivariational Inequalities with Anti-periodic Conditions

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Acta Mathematica Sinica,English Series 2024年第4期40卷 1143-1160页

作者： Jing zhao Chun Mei GAN zhen Hai LIU School of Mathematics and Quantitative Economics Guangxi University of Finance and EconomicsNanning 530003P.R.China Guangxi Colleges and Universities Key Laboratory of Optimization Control and Engineering Calculation Guangxi Minzu UniversityNanning 530006P.R.China

The goal of this paper is to deal with a new dynamic system called a differential evolution hemivariational inequality(DEHVI)which couples an abstract parabolic evolution hemivariational inequality and a nonlinear differential equation in a Banach space.First,by apply ing surjectivity result for pseudomonotone multivalued mappins and the properties of Clarke's subgradient,we show the nonempty of the solution set for the parabolic hemivariational inequality.Then,some topological properties of the solution set are established such as boundedness,closedness and convexity.Furthermore,we explore the upper semicontinuity of the solution mapping.Finally,we prove the solution set of the system(DEHVI)is nonempty and the set of all trajectories of(DEHVI)is weakly compact in C(I,X).

关键词： Differential parabolic hemivariational inequality Clarke subdifferential hyperbolicparabolic system parabolic-parabolic system existence result

Nuclearity and Finite-Representability in the System of Completely Integral Mapping Spaces

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Acta Mathematica Sinica,English Series 2024年第5期40卷 1197-1214页

作者： Zhe DONG Ji Cheng TAO ya Fei zhao Department of Mathematics Zhejiang UniversityHangzhou 310027P.R.China Department of Mathematics China Jiliang UniversityHangzhou 310018P.R.China Department of Mathematics Zhejiang International Studies UniversityHangzhou 310023P.R.China

In this paper,we investigate local properties in the system of completely integral mapping spaces.We introduce notions of injectivity,local reflexivity,exactness,nuclearity,finite-represent ability and WEP in the system of completely integral mapping spaces.First we obtain that any finite-dimensional operator space is injective in the system of completely integral mapping spaces.Furthermore we prove that C is the unique nuclear operator space and the unique exact operator space in this system.We also show that C is the unique operator space which is finitely representable in{T_(n)}n∈Nin this system.As corollaries,Kirchberg’s conjecture and QWEP conjecture in the system of completely integral mapping spaces are false.

关键词： Completely integral mapping space injectivity exactness nuclearity finite-representability WEP

Ca_(2)MnO_(4)-layered perovskite modified by NaNO_(3)for chemical-looping oxidative dehydrogenation of ethane to ethylene

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Chinese Journal of Chemical Engineering 2024年第4期68卷 53-64页

作者： Weixiao Ding Kun zhao Shican Jiang zhen Huang Fang He College of Chemistry and Bioengineering Guilin University of TechnologyGuilin 541006China Guangzhou Institute of Energy Conversion Chinese Academy of SciencesGuangzhou 510640China School of Chemistry and Chemical Engineering Nanjing University of Science and TechnologyNanjing 210094China

Chemical-looping oxidative dehydrogenation(CL-ODH)is a process designed for the conversion of alkanes into olefins through cyclic redox reactions,eliminating the need for gaseous O_(2).In this work,we investigated the use of Ca_(2)MnO_(4)-layered perovskites modified with NaNO_(3)dopants,serving as redox catalysts(also known as oxygen carriers),for the CL-ODH of-thane within a temperature range of 700-780℃.Our findings revealed that the incorporation of NaNO_(3)as a modifier significantly-nhanced the selectivity for-thylene generation from Ca_(2)MnO_(4).At 750℃and a gas hourly space velocity of 1300 h^(-1),we achieved an-thane conversion up to 68.17%,accompanied by a corresponding-thylene yield of 57.39%.X-ray photoelectron spectroscopy analysis unveiled that the doping NaNO_(3)onto Ca_(2)MnO_(4)not only played a role in reducing the oxidation state of Mn ions but also increased the lattice oxygen content of the redox catalyst.Furthermore,formation of NaNO_(3)shell on the surface of Ca_(2)MnO_(4)led to a reduction in the concentration of manganese sites and modulated the oxygen-releasing behavior in a step-wise manner.This modulation contributed significantly to the-nhanced selectivity for-thylene of the NaNO_(3)-doped Ca_(2)MnO_(4)catalyst.These findings provide compelling-vidence for the potential of Ca_(2)MnO_(4)-layered perovskites as promising redox catalysts in the context of CL-ODH reactions.

关键词： Chemical-looping oxidative dehydrogenation Ethane Ethylene NaNO_(3)-doped Ca_(2)MnO_(4)redox catalyst Layered perovskites

Effect of Direct Aging on Corrosion Behavior of AlSi10Mg Alloy Fabricated by Laser Powder Bed Fusion

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Acta Metallurgica Sinica(English Letters) 2024年第2期37卷 266-282页

作者： zhen Zhang Zhanyong zhao Xiaofeng Li Beibei Wang Peikang Bai Shanxi Key Laboratory of Controlled Metal Solidification and Precision Manufacturing School of Materials Science and EngineeringNorth University of ChinaTaiyuan030051China Technical Center Taiyuan Iron and Steel(Group)Co.LtdTaiyuan030003China School of Materials Science and Engineering Taiyuan University of Science and TechnologyTaiyuan030024China

Effect of direct aging of 170℃on corrosion behavior of laser powder bed fused AlSi10Mg(LPBF-AlSi10Mg)was studied by microstructure analysis,electrochemical analysis and X-ray photoelectron spectrometer.The results show that direct aging of 170℃has little effect on melt pool and Si cellular structure,but promotes the precipitation of nano-Si particles and releases the residual stress.With increasing aging time from 0 to 4 h to 24 h,the corrosion property of the LPBF-AlSi10Mg is deteriorated,which is evidenced by increased corrosion current density and decreased pitting potential and polarization resistance.With increasing the aging time,the thickness of the oxide film formed on surface of the LPBF-AlSi10Mg increases.The Si content of the oxide film of the sample aging for 4 h is the lowest,9.42 at.%,and it is the highest,18.62 at.%,for the sample aging for 24 h.The electrochemical noise analysis reveals that the middle-frequency contribution of the Hilbert spectrum is responsible for the deteriorated corrosion performance,which corresponds to metastable pitting initiated by nano-Si particles.

关键词： Laser powder bed fusion AlSi10Mg Direct aging Corrosion

Effects of host identity on the gut microbiota:A comparative study on three microtinae species

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Animal Models and Experimental Medicine 2024年第2期7卷 98-105页

作者： zhen yao Wenli zhao Baohong Tang Qinghua Li zhenlong Wang School of Life Sciences Zhengzhou UniversityZhengzhouHenan ProvinceP.R.China

Background:Gut microbiota exert an immense effect on host health and host environmental adaptation.Furthermore,the composition and structure of gut microbiota are determined by the environment and host genetic factors.However,the relative contribution of the environment and host genetic factors toward shaping the structure of gut microbiota has been poorly understood.Methods:In this study,we characterized the fecal microbial communities of the closely related voles Neodon fuscus,Lasiopodomys brandtii,and L.mandarinus after caged feeding in the laboratory for 6 months,through high-throughput sequencing and bioinformatics analysis.Results:The results of pairwise comparisons of N.fuscus vs.L.brandtii and L.mandarinus vs.L.brandtii revealed significant differences in bacterial diversity and composition after domestication.While 991 same operational taxonomic units(OTUs)were shared in three voles,there were 362,291,and 303 species-specific OTUs in N.fuscus,L.brandtii,and L.mandarinus,respectively.The relative abundances of Proteobacteria and Prevotella,which are reported to be enriched in high-altitude populations,were significantly higher in high-altitude N.fuscus than in low-altitude L.brandtii after domestication.Firmicutes,which produce various digestive enzymes for energy metabolism,and Spirochaetes,which can degrade cellulose,were found in higher abundance in subterranean L.mandarinus than that in L.brandtii which dwells on the earth surface.Conclusion:Our findings showed that some components of gut microbiota still maintained dominance even when different host species are reared under the same environmental conditions,suggesting that these bacteria are substantially influenced by host factors.

关键词： gut microbiota high-altitude Lasiopodomys brandtii Neodon fuscus