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The microstructure of a single crystal superalloy after different aging heat treatments

Rare Metals 2018年第3期37卷 210-216页

作者： xiao-dai yue Jia-Rong Li xiao-Guang Wang Science and Technology on Advanced High Temperature Structural Materials Laboratory Beijing Institute of Aeronautical Materials

To study the influence of aging heat treatments on the microstructure of single crystal superalloys with high content of refractory elements and optimal the aging heat treatment regimes, a single crystal superalloy containing 22 wt% refractory elements was *** show that for the experimental alloy, even the homogenization-solution heat treatment for 25 h cannot homogenize the alloying elements completely. During primary aging heat treatment, γ＇ phase grows larger and turns to regular cubes. Higher aging temperature induces larger γ＇ cubes. For specimens with primary aging heat treated at 1120 ℃,γ＇ morphology does not change apparently during secondary aging heat treatment. For specimens with primary aging heat treatment at 1150 ℃,γ＇phase in interdendrite grows obviously comparing with that in dendrites. By analyzing the precipitating kinetics of γ＇phase, it is found that owning to the dendrite segregation and different aging heat treatment temperatures, γ＇ phase at different regions grows under the control of different factors at different aging heat treatment stages. The two controlling factors that are driving forces of phase transformation and element diffusion rate induce obviously different growth rates of γ＇ phase. As a result, the γ＇-precipitating behaviors are variable based on different solute concentrations and aging temperatures. For advanced single crystal superalloys that are supposed to be used at relatively high temperatures, the final γ＇ size after aging heat treatment is suggested to be close to the crossing point of diffusion controlling curve and driving force controlling curve corresponding to the serving temperature. And then,high-temperature properties can be improved.

关键词： Single crystal superalloy Aging heat treatment γ' precipitation Kinetics

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Forming and growing mechanisms of homogenization-solution pores in a single crystal superalloy

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Rare Metals 2018年第5期37卷 399-406页

作者： xiao-dai yue Jia-Rong Li xiao-Guang Wang Zhen-Xue Shi Science and Technology on Advanced High Temperature Structural Materials Laboratory Beijing Institute of Aeronautical Materials

The forming and growing mechanisms of homogenization-solution pores in a single crystal superalloy were investigated. The microstructures were observed with optical microscope （OM） and field emission microscope （FEM） after homogenization-solution heat treated at 1328℃ and 1350 ℃ for 2 h, 6 h and 9 h. Results indicate that when heat treated at 1328 ℃, pores appear at the interface of eutectic and matrix at first and then leave in the matrix with the shrink of eutectic. When heat treated at 1350 ℃, incipient melting happens at first, and some of them have a pore in the center. After that, with the homogenization-solution process, incipient melting microstructure fades away gradually. By analyzing the results with thermodynamics and kinetics methods, it is concluded that some pores nucleate during directional solidification and then become larger and visible during homogenization-solution heat treatments; some pores are generated by incipient melting, yet such pores are difficult to be distinguished from other pores; imbalanced elements cross-diffusion induces to the forming and growing of pores too, and such imbalanced diffusion also plays an important part on the growth of all preexisting pores.

关键词： Single crystal superalloy Pore Homogenization Solution Heat treatment Incipient melting

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Effect of cellular recrystallization on tensile properties of a nickel-based single crystal superalloy containing Re and Ru

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Journal of Iron and Steel Research International 2017年第10期24卷 1059-1064页

作者： Zhen-xue Shi Shi-zhong Liu xiao-dai yue Li-jie Hu Wan-peng Yang xiao-guang Wang Jia-rong Li Science and Technology on Advanced High Temperature Structural Materials Laboratory Beijing Institute of Aeronautical MaterialsBeijing 100095China

A nickel-based single crystal superalloy containing Re and Ru was cast in a directional solidification *** single crystal specimens after standard heat treatment were grit blasted with different pressures and then heat treated at 1100°C for 4 hunder vacuum *** evolution of recrystallized microstructure and its effect on the tensile properties at 850 and 980°C were *** heat treatment,the cellular microstructure was observed,and the thickness of the cellular recrystallization zone increases with the increase in grit blasting *** appearance of the cellular structure undermines the tensile *** the tensile strength and elongation decrease with increasing the thickness of the cellular *** recrystallized grain boundaries can act as the channels for the crack initiation and propagation during tensile *** low bearing capacity of recrystallized layers and the local stress concentration resulting from the notch effect of cracking were the main reasons for the decrease of tensile properties.

关键词： Single crystal superalloy Cellular recrystallization Tensile property Microstructure Fracture morphology

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Refractory autoimmune hemolytic anemia in a patient with systemic lupus erythematosus and ulcerative colitis:A case report

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World Journal of Clinical Cases 2024年第13期12卷 2286-2292页

作者： dai-Xing Chen yue Wu Sui-Feng Zhang xiao-Jun Yang Department of Digestive System Chongqing Traditional Chinese Medicine HospitalChongqing 400021China

BACKGROUND Ulcerative colitis(UC)and systemic lupus erythematosus(SLE)are both systemic immunoreactive diseases,and their pathogenesis depends on the interaction between genes and environmental *** are no reports of UC with SLE in China,but six cases of SLE with UC have been reported in *** combination of these two diseases has distinct effects on the pathogenesis of both *** SUMMARY A female patient(30 years old)came to our hospital due to dull umbilical pain,diarrhea and mucous bloody stool in August 2018 and was diagnosed with *** symptoms were relieved after oral administration of mesalazine(1 g po tid)or folic acid(5 mg po qd),and the patient were fed a control *** June 24,2019,the patient was admitted for treatment due to anemia and *** hospitalization,the patient had repeated low-grade fever and a progressively decreased Hb *** tests revealed positive antinuclear antibody test,positive anti-dsDNA antibody,0.24 g/L C3(0.9-1.8 g/L),0.04 g/L C4(0.1-0.4 g/L),32.37 g/L immunoglobulin(8-17 g/L),and 31568.1 mg/24 h total 24-h urine protein(0-150 mg/24 h).The patient was diagnosed with SLE involving the joints,kidneys and blood *** reported cases of SLE were retrieved from PubMed to characterize clinicopathological features and identify prognostic factors for *** The patient was discharged in remission after a series of treatments,such as intravenous methylprednisolone sodium succinate,intravenous human immunoglobulin,cyclophosphamide injection,and plasma *** discharge,the patient took oral prednisone acetate tablets,cyclosporine capsules,hydroxychloroquine sulfate tablets and other treatments for symptoms and was followed up regularly for 1 month,after which the patient's condition continued to improve and stabilize.

关键词： Plasma exchange Autoimmune hemolytic anemia Systemic lupus erythematosus Ulcerative colitis Case report

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The Role of Renewable Protocatechol Acid in Epoxy Coating Modification: Significantly Improved Antibacterial and Adhesive Properties

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Chinese Journal of Polymer Science 2024年第1期42卷 63-72,I0008页

作者： Ming-Xuan Chen Jin-yue dai Li-yue Zhang Shuai-Peng Wang Jing-Kai Liu Yong-Gang Wu Xin-Wu Ba xiao-Qing Liu School of Chemistry and Materials Science Hebei UniversityBaoding 071000China Ningbo Institute of Materials Technology and Engineering Chinese Academy of SciencesNingbo 315201China Key Laboratory of Marine Materials and Related Technologies Chinese Academy of SciencesNingbo 315201China

It is of great significance to design epoxy coatings with superior antibacterial properties and high adhesive properties, as well as excellent processing, superior durability, and high transparency. However, it is still a challenge because of the common complex design and synthesis. Herein, the bio-based monomer protocatechuic acid(PCA) was used as raw material, the catechol structure with high bonding and antibacterial properties was introduced into the flexible alkane segment of ethylene glycol diglycidyl ether(EGDE) through an efficient, and green method, and it was cured with isophorone diamine(IPDA) to prepare corresponding thermosets. The cured resins exhibited excellent allaround qualities, particularly in bonding and antibacterial. When 30% PCA was added to pure epoxy resin, the adhesion between substrate and coating increased from 4.40 MPa to 13.60 MPa and the antibacterial rate of coating against E. coli and S. aureus could approach 100%. All of this is due to the fact that the catechol structure present in PCA has the ability to interact with various substrates and alter the permeability of bacterial cell membranes. The architecture of this method offers a fresh approach to dealing with the issues of challenging raw material selection and complex synthesis techniques.

关键词： Epoxy coatings Thermosets Catechol structure Antibacterial High adhesion

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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

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Molecular compositions and sources of organic aerosols at a rural site on the Guanzhong Plain,Northwest China:The importance of biomass burning

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Particuology 2024年第6期89卷 44-56页

作者： Yali Liu Minxia Shen Haijiao Liu Wenting dai Weining Qi Yifan Zhang Lu Li yue Cao Xin Wang xiao Guo Yingkun Jiang Jianjun Li State Key Laboratory of Loess and Quaternary Geology Key Lab of Aerosol Chemistry and PhysicsInstitute of Earth EnvironmentChinese Academy of SciencesXi'an 710061China Xi'an Institute for Innovative Earth Environment Research Xi'an 710061China National Observation and Research Station of Regional Ecological Environment Change and Comprehensive Management in the Guanzhong Plain ShaanxiChina

The concentration of PM_(2.5)has considerably reduced in recent years,but remains relatively high in *** particular,the increasing contribution of organic compounds to PM_(2.5)generates popular pressure for further reductions,resulting in an urgent need to study organic aerosol(OA).To investigate the molecular composition and source contribution of OA in the rural area of the Guanzhong Plain,Northwest China,PM_(2.5)samples were collected during 3–23 August 2016 and 5–20 January 2017 and studied for more than 100 organic tracer *** mean concentration of total measured organic compounds is 662±296 ng/m^(3)in summer and 3258±1925 ng/m^(3)in *** is the most abundant single compound found throughout the sampling period,which is a crucial tracer for biomass burning emissions,preliminary suggesting that biomass burning is an essential source of *** summer,organic compounds such as lipid compounds,sugar compounds,and polycyclic aromatic hydrocarbons(PAHs),more come from higher plants,wood burning,vehicle exhausts,plastic waste,and other direct emission *** PAHs(OPAHs),nitrophenols,and phthalic acids more come from the atmosphere through the oxidation reaction of aromatic precursors,especially photochemical ***,in winter,most of the increases in concentrations of organic compounds are attributed to biomass *** analysis of a haze event(14–19 January 2017)during the winter sampling period shows that the increases in the concentration of organic compounds are unaccompanied by strong secondary formation under lower relative humidity(49.1%±13.5%).The main reason for the growth of OA in this haze event is the accumulation of primary OA(POA).The source apportionment by the positive matrix factorization(PMF)model shows that biomass burning(37.1%)is the primary source of OA in the rural regions of the Guanzhong Plain,especially in winter(40.6%).The contribution of secondary formation decreases from 26.0%in summer t

关键词： Organic aerosol Molecular composition Seasonal variation Source apportionment Guanzhong Plain

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Clinical value of oral contrast-enhanced ultrasonography in diagnosis of gastric tumors

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World Journal of Gastrointestinal Oncology 2024年第1期16卷 110-117页

作者： Chuan-Yu Wang xiao-Jing Fan Fei-Liang Wang yue-yue Ge Zhao Cai Wei Wang Xin-Ping Zhou Jun Du De-Wei dai Department of Ultrasound Medicine Beijing HospitalBeijing 100005China Department of Gastroscopy Beijing HospitalBeijing 100005China Department of General Surgery Beijing HospitalBeijing 100005China Department of Pathology Beijing HospitalBeijing 100005China

BACKGROUND The incidence of gastric cancer remains high,and it is the sixth most common cancer and the fourth leading cause of cancer deaths *** contrastenhanced ultrasonography is a simple,non-invasive,and painless method for the diagnosis of gastric *** To explore the diagnostic value of oral contrast-enhanced ultrasonography for the detection of gastric *** The screening results based on oral contrast-enhanced ultrasonography and electronic gastroscopy were compared with those of the postoperative pathological *** Among 42 patients with gastric tumors enrolled in the study,the diagnostic accordance rate was 95.2%for oral contrast-enhanced ultrasonography(n=40)and 90.5%for electronic gastroscopy(n=38)compared with postoperative pathological *** Kappa value of consistency test with pathological findings was 0.812 for oral contrast-enhanced ultrasonography and 0.718 for electronic gastroscopy,and there was no significant difference between them(P=0.397).For the TNM staging of gastric tumors,the accuracy rate of oral contrast enhanced ultrasonography was 81.9%for the overall T staging and 50%,77.8%,100%,and 100%for T1,T2,T3,and T4 staging,*** sensitivity and specificity were both 100%for stages T3 and *** diagnostic accuracy rate of oral contrast-enhanced ultrasonography was 93.8%,80%,100%,and 100%for stages N0,N1-N3,M0,and M1,*** The accordance rate of qualitative diagnosis by oral contrast-enhanced ultrasonography is comparable to that of gastroscopy,and it could be used as the preferred method for the early screening of gastric tumors.

关键词： Oral contrast-enhanced ultrasonography Gastric tumor Electronic gastroscopy Controlled study Pathological examination Diagnosis

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Study on the optimal incident proton energy of ^(7)Li(p,n)^(7)Be neutron source for boron neutron capture therapy

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Nuclear Science and Techniques 2024年第3期35卷 170-180页

作者： Yi-Nan Zhu Zuo-Kang Lin Hai-Yan Yu Ye dai Zhi-Min dai xiao-Han Yu Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China University of Chinese Academy of Science Beijing 100049China

Boron neutron capture therapy(BNCT)is recognized as a precise binary targeted radiotherapy technique that effectively eliminates tumors through the^(10)B(n,α)^(7)Li nuclear *** various neutron sources,accelerator-based sources have emerged as particularly promising for BNCT ***^(7)Li(p,n)^(7)Be reaction is highly regarded as a potential neutron source for BNCT,owing to its low threshold energy for the reaction,significant neutron yield,appropriate average neutron energy,and additional *** study utilized Monte Carlo simulations to model the physical interactions within a lithium target subjected to proton bombardment,including neutron moderation by an MgF_(2)moderator and subsequent BNCT dose analysis using a Snyder head *** study focused on calculating the yields of epithermal neutrons for various incident proton energies,finding an optimal energy at 2.7 ***,the Snyder head phantom was employed in dose simulations to validate the effectiveness of this specific incident energy when utilizing a^(7)Li(p,n)^(7)Be neutron source for BNCT purposes.

关键词： Boron neutron capture therapy ^(7)Li(p,n)7Be neutron source Incident proton energy Monte Carlo simulation

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Intrinsically asymmetric atomic character regulates piezoelectricity in two-dimensional materials

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Frontiers of physics 2024年第3期19卷 153-162页

作者： Yun-Qin Li Qi-Wen He dai-Song Tang xiao Shang xiao-Chun Wang School of Physics Science and Information Technology Liaocheng UniversityLiaocheng 252000China Key Laboratory of Polar Materials and Devices Ministry of EducationDepartment of ElectronicsEast China Normal UniversityShanghai 200241China Institute of Atomic and Molecular Physics Jilin UniversityChangchun 130012China

Decreasing of layer thickness causes the decrease of polarization until it disappears due to the existence of depolarization ***,the search for strong piezoelectric materials is highly desirable for multifunctional ultra-thin piezoelectric ***,we propose a common strategy for achieving strong piezoelectric materials through the electronic asymmetry induced by the intrinsically asymmetric atomic character of different chalcogen ***,in the tetrahedral lattice structures,for example,M4X3Y3(M=Pd/Ni,X/Y=S,Se or Te,X≠Y)monolayers are proved to display excellent out-of-plane ***4Se3Te3 possesses the largest piezoelectric coefficient d33 of 61.57 pm/V,which is much larger than that of most 2D *** the electronic asymmetry further increases the out-of-plane piezoelectricity of Janus M4X3Y3 ***,the out-of-plane piezoelectricity is positively correlated with the ratio of electronegativity difference(Red)and the electric dipole moment(P).This work provides alternative materials for energy harvesting nano-devices or self-energized wearable devices,and supplies a valuable guideline for predicting 2D materials with strong out-of-plane piezoelectricity.

关键词： piezoelectricity intrinsically asymmetric atomic character ratio of electronegativity difference electric dipole moment first-principles calculations

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