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Preheating-assisted solid-state friction stir repair of Al-Mg-Si alloy plate at different rotational speeds

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International Journal of Minerals,Metallurgy and Materials 2024年第4期31卷 725-736页

作者： hui Wang Yidi Li Ming Zhang Wei Gong Ruilin lai Yunping Li State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China Research Institute of Light Alloy Central South UniversityChangsha 410083China

Additive friction stir deposition(AFSD)is a novel structural repair and manufacturing technology has become a research hotspot at home and abroad in the past five *** this work,the microstructural evolution and mechanical performance of the Al-Mg-Si alloy plate repaired by the preheating-assisted AFSD process were *** evaluate the tool rotation speed and substrate preheating for repair quality,the AFSD technique was used to additively repair 5 mm depth blind holes on 6061 aluminum alloy *** results showed that preheat-assisted AFSD repair significantly improved joint bonding and joint strength compared to the control non-preheat substrate ***,increasing rotation speed was also beneficial to improve the metallurgical bonding of the interface and avoid volume *** preheating conditions,the UTS and elongation were positively correlated with rotation *** the process parameters of preheated substrate and tool rotation speed of 1000 r/min,defect-free specimens could be obtained accompanied by tensile fracture occurring in the substrate rather than the repaired *** UTS and elongation reached the maximum values of 164.2MPa and 13.4%,which are equivalent to 99.4%and 140%of the heated substrate,respectively.

关键词： additive friction stir deposition structural repair tool rotation speed Al alloy

A survey on model-based reinforcement learning

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Science China(Information Sciences) 2024年第2期67卷 59-84页

作者： Fan-Ming LUO Tian XU Hang lai Xiong-hui CHEN Weinan ZHANG Yang YU National Key Laboratory for Novel Software Technology Nanjing University Polixir. ai Department of Computer Science and Engineering Shanghai Jiao Tong University

Reinforcement learning(RL) interacts with the environment to solve sequential decision-making problems via a trial-and-error approach. Errors are always undesirable in real-world applications, even though RL excels at playing complex video games that permit several trial-and-error attempts. To improve sample efficiency and thus reduce errors, model-based reinforcement learning(MBRL) is believed to be a promising direction, as it constructs environment models in which trial-and-errors can occur without incurring actual costs. In this survey, we investigate MBRL with a particular focus on the recent advancements in deep RL. There is a generalization error between the learned model of a non-tabular environment and the actual environment. Consequently, it is crucial to analyze the disparity between policy training in the environment model and that in the actual environment, guiding algorithm design for improved model learning, model utilization, and policy training. In addition, we discuss the recent developments of model-based techniques in other forms of RL, such as offline RL, goal-conditioned RL, multi-agent RL, and meta-RL. Furthermore,we discuss the applicability and benefits of MBRL for real-world tasks. Finally, this survey concludes with a discussion of the promising future development prospects for MBRL. We believe that MBRL has great unrealized potential and benefits in real-world applications, and we hope this survey will encourage additional research on MBRL.

关键词： reinforcement learning model-based reinforcement learning planning model learning model learning with reduced error model usage

Synthesis and Enhanced Acetone-sensing Properties of Ordered Large-pore Mesoporous Nickel Oxides with Ultrathin Crystalline Frameworks

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Chemical Research in Chinese Universities 2024年第3期40卷 521-528页

作者： SHAO Chen GUO Ru LI hui WANG Xiaozhong YANG Qingfeng lai Xiaoyong State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering School of Chemistry and Chemical EngineeringNingxia UniversityYinchuan 750021P.R.China

Acetone is a tracer for monitoring air quality and a potential breath maker for diabetes. It remains a great challenge for current portable sensors to sensitively and selectively detect acetone at low-ppb (part per billion) level. Herein, we present an ordered mesoporous nickel oxide (NiO) with both large mesopores and ultrathin crystalline frameworks for the detection of low-ppb acetone. The ordered mesoporous NiO replicas with predominant large mesopores of 11 nm, high specific surface areas of 121–128 m2/g and ultrathin crystalline frameworks of 5 nm were synthesized by the nanocasting method and the crystalline properties of NiO frameworks were adjusted by changing the annealing temperature from 300℃ to 750℃, which resulted in different contents of oxygen deficient on the surface of ultrathin frameworks. The gas-sensing properties for all the NiO samples were investigated and the ordered large-pore mesoporous NiO (NiO-600) with maximum oxygen deficient obtained at 600℃ exhibited the highest response (R_(gas)/R_(air)−1=2.9) toward acetone (1 ppm, ppm: part per million), which is 3.4 and 30 times larger than those for common mesoporous NiO obtained at 300℃ and bulk NiO. Notably, a low detection limit (2 ppb), good selectivity and cycling stability were also observed in NiO-600.

关键词： Mesoporous semiconductor NiO Gas sensing Acetone

Effect of crystal morphology of ultrahigh-nickel cathode materials on high temperature electrochemical stability of lithium ion batteries

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Journal of Energy Chemistry 2024年第1期88卷 327-335,I0008页

作者： Bi Luo hui Li Haoyu Qi Yun Liu Chuanbo Zheng Weitong Du Jiafeng Zhang lai Chen School of Metallurgy Engineering Jiangsu University of Science and TechnologyZhangjiagang 215600JiangsuChina National Engineering Laboratory for High-Efficiency Recovery of Refractory Nonferrous Metals School of Metallurgy and EnvironmentCentral South UniversityChangsha 410083HunanChina School of Materials Science and Engineering Beijing Key Laboratory of Environmental Science and EngineeringBeijing Institute of TechnologyBeijing 100081China

Higher nickel content endows Ni-rich cathode materials LiNi_(x)Co_yMn_(1-x-y)O_(2)(x>0.6)with higher specific capacity and high energy density,which is regarded as the most promising cathode materials for Li-ion ***,the deterioration of structural stability hinders its practical application,especially under harsh working conditions such as high-temperature *** these circumstances,it becomes particularly critical to clarify the impact of the crystal morphology on the structure and high-temperature performance as for the ultrahigh-nickel ***,we conducted a comprehensive comparison in terms of microstructure,high-temperature long-cycle phase evolution,and high-temperature electrochemical stability,revealing the differences and the working mechanisms among polycrystalline(PC),single-crystalline(SC)and Al doped SC ultrahigh-nickel *** results show that the PC sample suffers a severe irreversible phase transition along with the appearance of microcracks,resulting a serious decay of both average voltage and the energy *** the Al doped SC sample exhibits superior cycling stability with intact layered ***-situ XRD and intraparticle structural evolution characterization reveal that Al doping can significantly alleviate the irreversible phase transition,thus inhibiting microcracks generation and enabling enhanced ***,it exhibits excellent cycling performance in pouch-type full-cell with a high capacity retention of 91.8%after 500 cycles at 55℃.This work promotes the fundamental understanding on the correlation between the crystalline morphology and high-temperature electrochemical stability and provides a guide for optimization the Ni-rich cathode materials.

关键词： Single-crystalline Ultrahigh-nickel cathode High-temperature performance Phase evolution

Random Terpolymer Based on Simple Siloxane-functionalized Thiophene Unit Enabling High-performance Non-fullerene Organic Solar Cells

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Chinese Journal of Polymer Science 2024年第3期42卷 311-321,I0006页

作者： Fuliang Cheng Shiting lai Yihan Zhang Ling xue Xinxin Xia Peipei Zhu Xinhui Lu Xunfan Liao Yiwang Chen National Engineering Research Center for Carbohydrate Synthesis/Key Laboratory of Fluorine and Silicon for Energy Materials and Chemistry of Ministry of Education College of Chemistry and Chemical EngineeringJiangxi Normal UniversityNanchang 330022China Department of Physics Chinese University of Hong Kong New TerritoriesHong Kong 999077China Institute of Polymers and Energy Chemistry(IPEC)/Jiangxi Provincial Key Laboratory of New Energy Chemistry Nanchang UniversityNanchang 330031China

Incorporation of siloxane-functionalized units into polymers backbone has proven to be an efficient strategy to improve photovoltaic performance. In this work, a low-cost siloxane-containing unit was developed to construct a series of terpolymers, and the effects of siloxane on the polymer performance were systematically studied. Different contents of thiophene containing siloxane-functionalized side chain were introduced into PM6 to obtain a series of polymers(PM6, PM6-SiO-10, PM6-SiO-20 and PM6-SiO-30). The siloxane-functionalized side chains in polymers have only a slight effect on the absorption behavior and frontier molecular orbitals. However, when the siloxane content increased, the terpolymers' aggregation property decreased and the temperature-dependency increased, leading to improved donor-acceptor compatibility. The power conversion efficiency(PCE) based on PM6:Y6, PM6-SiO-20:Y6 and PM6-SiO-30:Y6 devices was 15.64%, 16.03% and 15.82%, respectively. In comparison, the active layer based on PM6-SiO-10:Y6 exhibits the most appropriate phase separation morphology, resulting in effective exciton dissociation, more balanced hole-electron transport and less recombination. Consequently, the highest PCE of 16.69% with an outstanding shortcircuit current density of 26.96 mA·cm^(-2) was obtained, which are one of the highest values for siloxane-functionalized polymer-based *** work demonstrates that finely controlling the content of siloxane-functionalized thiophene is beneficial for obtaining high-performance terpolymer donors and provides a novel and low-cost method to improve photovoltaic performance.

关键词： Organic solar cells Terpolymers Siloxane-functionalized unit Low-cost Morphology

Retinoic acid alleviates rotavirus-induced intestinal damage by regulating redox homeostasis and autophagic flux in piglets

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Animal Nutrition 2024年第1期16卷 409-421页

作者： Xin lai Aimin Wu Bing Yu hui Yan Junqiu Luo Ping Zheng Jie Yu Daiwen Chen Institute of Animal Nutrition Sichuan Agricultural University Key Laboratory for Animal Disease-resistance Nutrition of China Ministry of Education Sichuan Agricultural University

Rotaviruses(RV) are a major cause of severe gastroenteritis, particularly in neonatal piglets. Despite the availability of effective vaccines, the development of antiviral therapies for RV remains an ongoing challenge. Retinoic acid(RA), a metabolite of vitamin A, has been shown to have anti-oxidative and antiviral properties. However, the mechanism by which RA exerts its intestinal-protective and antiviral effects on RV infection is not fully understood. The study investigates the effects of RA supplementation in Duroc × Landrace × Yorkshire(DLY) piglets challenged with RV. Thirty-six DLY piglets were assigned into six treatments, including a control group, RA treatment group with two concentration gradients(5and 15 mg/d), RV treatment group, and RV treatment group with the addition of different concentration gradients of RA(5 and 15 mg/d). Our study revealed that RV infection led to extensive intestinal architecture damage, which was mitigated by RA treatment at lower concentrations by increasing the villus height and villus height/crypt depth ratio(P < 0.05), enhancing intestinal stem cell signaling and promoting intestinal barrier functions. In addition, 15 mg/d RA supplementation significantly increased NRF2 and HO-1 protein expression(P < 0.05) and GSH content(P < 0.05), indicating that RA supplementation can enhance anti-oxidative signaling and redox homeostasis after RV challenge. Additionally,the research demonstrated that RA exerts a dual impact on the regulation of autophagy, both stimulating the initiation of autophagy and hindering the flow of autophagic flux. Through the modulation of autophagic flux, RA influence the progression of RV infection. These findings provide new insights into the regulation of redox hemostasis and autophagy by RA and its potential therapeutic application in RV infection.

关键词： Rotavirus Piglet Retinoic acid Intestinal barrier Redox hemostasis Autophagic flux

Comparative analysis shows high level of lineage sorting in genomic regions with low recombination in the extended Picea likiangensis species complex

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Plant Diversity 2024年第4期46卷 547-550页

作者： hui Zhu Weixiao Lei Qing lai Yongshuai Sun Dafu Ru State Key Laboratory of Grassland Agro-ecosystems College of EcologyLanzhou UniversityLanzhou 730000China CAS Key Laboratory of Tropical Forest Ecology Xishuangbanna Tropical Botanical GardenChinese Academy of SciencesMengla 666303China Xi'an Center for Disease Control and Prevention Xi'an 710068China

Genome-scale data,while promising for illuminating phylogenetic relationships,frequently pose a conundrum by yielding conflicting topologies and highly variable gene tree distributions(Pease et al.,2016).This complexity likely arises from the reticulate evolution observed in many taxa,where genetic information exchange occurs through diverse biological processes.

关键词： sorting processes. yielding

T-tube bridging fistula jejunal anastomosis for treatment of pancreatic lumbar dorsal fistula after necrotizing pancreatitis

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Hepatobiliary & Pancreatic Diseases International 2024年第4期23卷 428-430页

作者： Su-lai Liu Guo-Guang Li Wei Cheng Chuang Peng Ying-hui Song Department of Hepatobiliary Surgery Hunan Provincial People’s Hospital/The First Affiliated Hospital of Hunan Normal UniversityChangsha 410000China

Infectious pancreatic necrosis causes external pancreatic fistula in some ***,external pancreatic fistula requires fistula-gastric and/or intestinal anastomosis,and digestive endoscopic interventional treatment[1–3].It is especially difficult to treat external pancreatic fistulas with small fistulas where the external fistula is located in the lower *** common treatment is to remove the body and tail of the pancreas and the *** operation is very traumatic.A new pancreatic fistula may still occur at the pancreatic *** above operations may lead to unnecessary resection of the spleen,colon injury and other *** order to solve this problem,we innovatively used T-tube bridging fistula jejunal anastomosis plus continuous negative pressure suction to treat three cases of external pancreatic fistulas in the lower back,and all of them achieved good results.

关键词： fistula anastomosis spleen

d-d Orbital coupling induced by crystal-phase engineering assists acetonitrile electroreduction to ethylamine

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Journal of Energy Chemistry 2024年第2期89卷 216-225,I0006页

作者： Honggang Huang Yao Chen hui Fu Cun Chen Hanjun Li Zhe Zhang Feili lai Shuxing Bai Nan Zhang Tianxi Liu Key Laboratory of Synthetic and Biological Colloids Ministry of EducationSchool of Chemical and Material EngineeringJiangnan UniversityWuxi 214122JiangsuChina Department of Chemistry KU LeuvenCelestijnenlaan 200FLeuven 3001Belgium College of Chemistry and Chemical Engineering Qingdao UniversityQingdao 266071ShandongChina

The d-d orbital coupling induced by crystal-phase engineering can effectively adjust the electronic structure of electrocatalysts,thus showing significant catalytic performance,while it has been rarely explored in electrochemical acetonitrile reduction reaction(ARR)to ***,we successfully realize the structural transformation of Pd Cu metallic aerogels(MAs)from face-centered cubic(FCC)to body-centered cubic(BCC)through annealing ***,the BCC Pd Cu MAs exhibit excellent ARR performance with high ethylamine selectivity of 90.91%,Faradaic efficiency of 88.60%,yield rate of 316.0 mmol h^(-1)g^(-1)_(Pd+Cu)and long-term stability for consecutive electrolysis within 20 h at-0.55 V *** hydrogen electrode,outperforming than those of FCC Pd Cu *** the membrane electrode assembly system,BCC Pd Cu MAs also demonstrate excellent ethylamine yield rate of 389.5 mmol h^(-1)g^(-1)_(Pd+Cu).Density functional theory calculation reveals that the d-d orbital coupling in BCC Pd Cu MAs results in an evident correlation effect for the interaction of Pd and Cu sites,which boosts up the Cu sites electronic activities to enhance ARR *** work opens a new route to develop efficient ARR electrocatalysts from the perspective of crystalline structure transformation.

关键词： d-d Orbital coupling Crystal-phase engineering Metallic aerogels Acetonitrile electroreduction reaction Ethylamine