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Hot deformation behavior and processing parameter optimization of BT25y alloy with an initial equiaxed microstructure using processing map

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Rare Metals 2018年第9期37卷 778-788页

作者： Xue-Mei Yang Hong-Zhen Guo ze-kun yao Shi-Chong Yuan She-Wei Xin School of Materials Science and Engineering Northwestern Polytechnical University Deyang Wan Hang Die Forging Co. Ltd.China National Erzhong Group Co. Titanium Alloy Research Center Northwest Institute for Nonferrous Metal Research

The high-temperature plastic deformation behavior of BT25y alloy with an initial equiaxed microstructure was investigated by hot compression tests. Processing maps were established to evaluate the power dissipation efficiency （η） and identify the flow instability regions. When the strain reaches steady state, the optimum processing window is distributed in the area covering most of the studied deformation temperatures and strain rates of 1 × 10-2 to 1× 10-1 s-1. True strain has great effects on the power dissipation efficiency under the condition of 880 ℃/1× 10-3 s-1, but the efficiency values remain approximately constant （η= 0.40） at conditions of 900-940 ℃/1× 10-2 to 1 × 10-1 S-1 and 980-1000 ℃/ 1× 10-1 s- 1. Besides, the instability regions are distributed in high strain rate areas no matter how many of the strains. Based on the processing map and microstructural observa- tion, it can be concluded that the deformation mechanisms related to Region I with small strain rate and lower temper- ature in α＋β phase field, Region II with medium strain rate and higher temperature inα＋β phase field, Region III with medium strain rate and high temperature in βphase field are superplasticity and strain-induced transformation, dynamicrecrystallization （DRX） and phase transformation, β phase dynamic recovery and local DRX, respectively.

关键词： BT25y alloy Hot deformation Processingmap Microstructural evolution

Dependence of α-phase size on flow stress during dynamic recrystallization steady state in Ti60 alloy

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Rare Metals 2017年第11期36卷 851-857页

作者： hui li zhang-long zhao hong-zhen guo yong-quan ning ze-kun yao kai li vSchool of Materials Science and Engineering NorthwesternPolytechnical University Xi'an 710072 China

The dependence of α-phase size on flow stress was characterized by a proposed kinetic model during dynamic recrystallization （DRX） steady state in Ti60 alloy. Accord- ing to the isothermal compression tests, the influence of deformation parameters on the steady-state flow stress was analyzed and the constitutive equation was established to predict the steady-state flow stress under different defor- mation temperatures and strain rates. A power-law rela- tionship between the DRX average grain size and steady- state flow stress with an exponent of -2 is obtained from the dynamic balance during DRX steady state. The effect of deformation parameters on at-phase size was observed through the microstructure after deformation, and the applicability of the model for Ti60 alloy was verified by the comparison between predicted and experimental data.

关键词： Dynamic recrystallization Steady state Grainsize Ti60 alloy Hot deformation

Effect of dynamic loading orientation on fracture properties of surrounding rocks in twin tunnels

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第2期16卷 393-409页

作者： ze Deng Zheming Zhu Lei Zhou Leijun Ma Jianwei Huang yao Zhang Key Laboratory of Deep Earth and Engineering(Ministry of Education) College of Architecture and EnvironmentSichuan UniversityChengdu610065China Failure Mechanics and Engineering Disaster Prevention Key Laboratory of Sichuan Province College of Architecture and EnvironmentSichuan UniversityChengdu610065China Institute for Disaster Management and Reconstruction Sichuan UniversityChengdu610065China

For expedited transportation,vehicular tunnels are often designed as two adjacent tunnels,which frequently experience dynamic stress waves from various orientations during blasting *** analyze the impact of dynamic loading orientation on the stability of the twin-tunnel,a split Hopkinson pressure bar(SHPB)apparatus was used to conduct a dynamic test on the twin-tunnel *** two tunnels were rotated around the specimen’s center to consider the effect of dynamic loading ***-DYNA software was used for numerical simulation to reveal the failure properties and stress wave propagation law of the twin-tunnel *** findings indicate that,for a twin-tunnel exposed to a dynamic load from different orientations,the crack initiation position appears most often at the tunnel corner,tunnel spandrel,and tunnel *** the impact direction is created by a certain angle(30°,45°,60°,120°,135°,and 150°),the fractures are produced in the middle of the line between the left tunnel corner and the right tunnel *** the impact loading angle(a)is 90°,the tunnel sustains minimal damage,and only tensile fractures form in the surrounding *** orientation of the impact load could change the stress distribution in the twin-tunnel,and major fractures are more likely to form in areas where the tensile stress is concentrated.

关键词： Twin-tunnel Dynamic load Split Hopkinson pressure bar(SHPB) Fracture mode Stress distribution Displacement field distribution

Intelligent Predetermination of Generator Tripping Scheme: Knowledge Fusion-based Deep Reinforcement Learning Framework

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 66-75页

作者： Lingkang zeng Wei yao ze Hu Hang Shuai Zhouping Li Jinyu Wen Shijie Cheng State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronics EngineeringHuazhong University of Science and TechnologyWuhan 430074China Dispatching and Control Center Central China Branch of State Grid Corporation of ChinaWuhan 430077China. Department of Electrical Engineering and Computer Science University of TennesseeKnoxvilleTN 37996USA

Generator tripping scheme(GTS)is the most commonly used scheme to prevent power systems from losing safety and ***,GTS is composed of offline predetermination and real-time scenario ***,it is extremely time-consuming and labor-intensive for manual predetermination for a large-scale modern power *** improve efficiency of predetermination,this paper proposes a framework of knowledge fusion-based deep reinforcement learning(KF-DRL)for intelligent predetermination of ***,the Markov Decision Process(MDP)for GTS problem is formulated based on transient instability ***,linear action space is developed to reduce dimensionality of action space for multiple controllable ***,KF-DRL leverages domain knowledge about GTS to mask invalid actions during the decision-making *** can enhance the efficiency and learning ***,the graph convolutional network(GCN)is introduced to the policy network for enhanced learning *** simulation results obtained on New England power system demonstrate superiority of the proposed KF-DRL framework for GTS over the purely data-driven DRL method.

关键词： Deep reinforcement learning generator tripping scheme graph convolutional network invalid action masking knowledgefusion

Crystallization management of CsPbI_(2)Br perovskites by PbAc_(2)-incorporated twice spin-coating process for efficient and stable CsPbI_(2)Br perovskite solar cells

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Journal of Energy Chemistry 2024年第10期97卷 419-428,I0008页

作者： Yu Liu kun Lang Huifang Han Huijing Liu yao Fu Pengchen Zou Yinhui Lyu Jia Xu Jianxi yao State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources Beijing Key Laboratory of Energy Safety and Clean UtilizationNorth China Electric Power UniversityBeijing 102206China

CsPbI_(2)Br perovskite solar cell has been extensively studied due to its exceptional thermal stability and relatively stable perovskite phase ***,the presence of bromine leads to a rapid crystallization rate of CsPbI_(2)Br films,resulting in small grain size and high defect ***,CsPbI_(2)Br demonstrates poor light absorption due to its wide ***,it is crucial to control the crystallization rate and increase the film thickness to reduce defect density,enhance light absorption,and improve photovoltaic *** this study,we utilized a PbAc_(2)-incorporated twice spincoating(PTS) process to address these ***,PbAc_(2) was added to the CsPbI_(2)Br precursor solution to form a CsPbI_(2)Br film,which was then coated with the CsPbI_(2)Br precursor solution to produce the PTS film,Ac^(-)can delay the perovskite crystallization,leading to the formation of thicker and denser CsPbI_(2)Br ***,lone-pair electrons of the oxygen atom provided by Ac^(-)formed coordination bonds with under-coordinated Pb~(2+) ions to fill halogen ion vacancies,thereby reducing the defect ***,the PTS CsPbI_(2)Br device achieved a peak power conversion efficiency(PCE) of 16.19% and maintained 96.7% of its initial PCE over 1500 h at room temperature under 25% relative humidity without any encapsulation.

关键词： CsPbI_(2)Br Twice spin-coating process PbAc_(2) Crystallization management Perovskite solar cells

Potential Benefits of Green Tea in Prostate Cancer Prevention and Treatment: A Comprehensive Review

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Chinese Journal of Integrative Medicine 2024年第11期30卷 1045-1055页

作者： LIU Gui-hong yao ze-qin CHEN Guo-qiang LI Ya-lang LIANG Bing Department of Urology Sanya Central Hospital (The Third People's Hospital of Hainan Province) Department of Urology Yuzhou People's Hospital

Prostate cancer is a prevalent and debilitating disease that necessitates effective prevention and treatment strategies. Green tea, a well-known beverage derived from the Camellia sinensis plant, contains bioactive compounds with potential health benefits, including catechins and polyphenols. This comprehensive review aims to explore the potential benefits of green tea in prostate cancer prevention and treatment by examining existing literature. Green tea possesses antioxidant, anti-inflammatory, and anti-carcinogenic properties attributed to its catechins, particularly epigallocatechin gallate. Epidemiological studies have reported an inverse association between green tea consumption and prostate cancer risk, with potential protection against aggressive forms of the disease. Laboratory studies demonstrate that green tea components inhibit tumor growth, induce apoptosis, and modulate signaling pathways critical to prostate cancer development and progression. Clinical trials and human studies further support the potential benefits of green tea. Green tea consumption has been found to be associated with a reduction in prostate-specific antigen levels, tumor markers, and played a potential role in slowing disease progression. However, challenges remain, including optimal dosage determination, formulation standardization, and conducting large-scale, long-term clinical trials. The review suggests future research should focus on combinatorial approaches with conventional therapies and personalized medicine strategies to identify patient subgroups most likely to benefit from green tea interventions.

关键词： epigallocatechin gallate green tea prevention prostate cancer review treatment

Achieving highly efficient long-wavelength phosphorescence emission of large singlet-triplet energy gap materials by host-guest doping

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Science China Chemistry 2024年第6期67卷 1922-1928页

作者： Shasha Zhang Wei yao Anqi Lv kun Liu Yusheng Zhang Chifeng Zhou Huili Ma Huifang Shi Zhongfu An Key Laboratory of Flexible Electronics(KLOFE)&Institute of Advanced Materials(IAM) Nanjing Tech UniversityNanjing211816China

High-efficiency long-wavelength phosphorescence emissions of large singlet-triplet energy gap(ΔE_(ST))materials are essential for applications in biology and ***,few long-wavelength phosphorescence emissions of largeΔE_(ST)materials have been reported due to the weak spin-orbit coupling(SOC)and strong non-radiative ***,we develop a strategy to achieve highly efficient long-wavelength room temperature phosphorescence(RTP)emission of largeΔE_(ST)materials,which display bright red RTP emission with above 400μs lifetime and 6.5%phosphorescent quantum *** experiments and theoretical calculations reveal that the fishbone-like packing and the zig-zag interactions provide favorable conditions for suppressing the non-radiative transitions of triplet state excitons,and heavy atoms effectively promote the intersystem crossing(ISC)process for highly efficient long-wavelength phosphorescence *** universality of the method for highly efficient long-wavelength RTP emission of largeΔE_(ST)materials was further investigated in various ***,these materials with largeΔE_(ST)manifest the advantages of large color contrast on the display and utilization potentiality in information *** strategy paves the way for the high contrast display and development of information encryption with RTP emission.

关键词： room temperature phosphorescence singlet-triplet energy gap host-guest doping heavy atom effect red phosphorescence

Single-atom Rh catalysts for efficiently degrading Rhodamine B with high concentration

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Rare Metals 2024年第5期43卷 2331-2338页

作者： Shou-yao Hu Jian-Ping Guan Run-ze Ma Yu Tao Dong-Hao Liu Jia-Xin Gong Yu Xiong Department of Chemistry and Chemical Engineering Central South UniversityChangsha 410083China

Highly concentrated dye wastewater has a serious effect on the quality of natural waters;thus,developing novel catalysts to degrade dyes rapidly and efficiently is of great *** the first time,this study reports an Rh single atom loaded on a nitrogen-doped carbon(SA-Rh/CN)*** catalyst exhibits an excellent processing capacity for high concentrations of Rhodamine B(Rh B),high catalytic activity(95.7% degradation of Rh B in60 min)and excellent stability(93.5% degradation efficiency after 10 stable runs).

关键词： catalyst. catalysts loaded

Molecular Engineering of Aptamer to Solubilize Hydrophobic Near-Infrared Photosensitizer for Enhanced Cancer Photodynamic Therapy

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CCS Chemistry 2024年第5期6卷 1240-1254页

作者： Rongjun Zhang Ding-kun Ji Defan yao zeyu Xiao Weihong Tan Institute of Molecular Medicine(IMM) Renji HospitalState Key Laboratory of Oncogenes and Related GenesShanghai Jiao Tong University School of MedicineShanghai 200240 Department of Radiology Xinhua HospitalShanghai Jiao Tong University School of MedicineShanghai 200092 Department of Pharmacology and Chemical Biology School of MedicineShanghai Jiao Tong UniversityShanghai 200025 Zhejiang Cancer Hospital Hangzhou Institute of Medicine(HIM)The Chinese Academy of SciencesHangzhouZhejiang 310022 Molecular Science and Biomedicine Laboratory(MBL) State Key Laboratory of Chemo/Biosensing and ChemometricsCollege of Chemistry and Chemical EngineeringCollege of BiologyAptamer Engineering Center of Hunan ProvinceHunan UniversityChangshaHunan 410082

Photodynamic therapy(PDT)is a clinically representative treatment strategy for ***,conventional photosensitizers(PSs)are usually hampered by poor water solubility and low targeting ***,we report the precise molecular engineering of aptamer oligonucleotides to solubilize hydrophobic near-infrared(NIR)PSs for enhanced cancer *** pyropheophorbide A(PA)is precisely conjugated to aptamer oligonucleotides by combing DNA solid-phase synthesis technology and Cu-free click *** coupling of insoluble PA to hydrophilic aptamer oligonucleotides vastly improves its solubility to as high as 750μM in water without any cosolvent,resulting in an enhanced NIR fluorescence property(quantum yield=23%)and ***,the targeting ability of aptamer oligonucleotides is not affected by our molecular engineering *** reactive oxygen species(ROS)are produced intracellularly with 660 nm laser irradiation,eliciting mitochondria damage and cell *** growth is effectively inhibited with a single dose of aptamer-PA conjugates without in vivo *** therapeutic effect is more than 20-fold higher than that of *** with traditional formulation,using aptamer oligonucleotides as functional carriers to solubilize hydrophobic NIR PSs is more precise and *** DNA molecular engineering strategy paves a way for the rational design of molecularly targeted medicine for future clinical cancer therapy.

关键词： aptamer aptamer-drug conjugates photosensitive drugs targeted photodynamic therapy cancer theranostics