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Environmental Simulation Experiments of 3D-C/Sic Composites With Different Pyc Interfacial layers

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Environmental Simulation Experiments of 3D-C/Sic Composites ...

STUDY ON C-fIBER-REINfORCED CElSIAN-MATRIX COMPOSITES

The fourth International Conference on Physical and Numerical Simulation of Materials (ICPNS’2004)

作者： N.DONG Y.D.XU l.f.cheng l.T.ZHANG State Key laboratory of Solidification Northwestern Pohlechnical University. Xi’an 710072 China State Key laboratory of Solidification Northwestern Pohlechnical University. Xi’an 710072 China State Key laboratory of Solidification Northwestern Pohlechnical University. Xi’an 710072 China State Key laboratory of Solidification Northwestern Pohlechnical University. Xi’an 710072 China

＜正＞A series of 3D-C/SiC composites with different pyrolytic carbon （PyC） interfacial layers （about 20-300nm thick） were prepared by chemical vapor infiltration. Simulation experiments at different temperatures were performed by exposing C/SiC specimens in single and coupling gases partial pressure atmospheres, namely, O2, H2O vapor and molten salt （Na+） vapor. It suggested that at intermediate temperature range （about 600-800℃） a dramatic effect of PyC thickness on the weight and strength change of C/SiC was shown, which was mainly influenced by O2 partial pressure;at high temperature range （about 1200-1300℃） the effect was not obvious relatively, which might be influenced by H2O vapor partial pressure;and finally at very high temperature range （＞1500℃） the molten salt vapor was the factor of most possibility affecting the weight change of C/SiC.

关键词： C/SiC Interfacial layer Simulation experiment

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Acta Metallurgica Sinica(English letters) 1999年第5期12卷 1094-1098页

作者： X.W.Yin, l.f.cheng,l.T.Zhang, W.C.Zhou and Y.D.Xu State Key laboratory of Solidification Processing, Northwestern Polytechnical University, Xi′an 710072, China

Strong, tough, and almost fully dense C fiber reinforced celsian matrix composites have been fabricated by impregnation of the fiber tows with the matrix slurry, winding on a drum, drying, stacking the prepreg tapes in the desired orientation, and hot pressing. The monoclinic celsian phase in the matrix was produced in situ, during hot pressing, from amphosous BAS. The unidirectional composites having ≈20 vol% of fibers exhibited graceful failure with extensive fiber pullout in three point bend tests at room temperature. Values of ultimate flexural strength and fracture toughness were 379MPa and 8 3MPa·m 1/2 , respectively.

关键词： barium aluminosilicate celsian composite sol gel carbon fiber

Complex-frequency waves:beat loss and win sensitivity

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light(Science & Applications) 2024年第2期13卷 181-183页

作者： Qingqing cheng Tao l School of Optical-Electrical and Computer Engineering University of Shanghai for Science and TechnologyShanghai200093China Department of Respiratory Diseases and Critical Medicine Quzhou Hospital Affiliated to Wenzhou Medical UniversityQuzhou324000China National laboratory of Solid State Microstructures College of Engineering and Applied SciencesNanjing UniversityNanjing210093China

Recent experiments have demonstrated that synthesized complex-frequency waves can impart a virtual gain to molecule sensing systems,which can effectively restore information lost due to intrinsic molecular *** enhancement notably amplifies the signal of trace molecular vibrational fingerprints,thereby substantially improving the upper limit of sensitivity.

关键词： thereby Complex limit

Cognition and movement in neurodegenerative disorders:a dynamic duo

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Neural Regeneration Research 2024年第10期19卷 2101-2102页

作者： Marit f.l.Ruitenberg Department of Health Medical and NeuropsychologyLeiden UniversityLeidenthe Netherlands leiden Institute for Brain and Cognition Leidenthe Netherlands

People with neurodegenerative disorders often experience problems across a variety of functional domains,including cognition,movement,and psychosocial *** classification of these disorders is based on the phenotypical manifestations that represent the most prominent clinical *** example,Parkinson's disease and Huntington's disease are typically regarded as movement disorders,whereas Alzheimer's disease(AD) and other dementias are regarded as cognitive disorders.

关键词： disorders Huntington degenerative

Triple reverse order law for the Drazin inverse

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Applied Mathematics(A Journal of Chinese Universities) 2024年第1期39卷 55-68页

作者： WANG Hua ZHONG cheng-cheng College of Sciences Inner Mongolia University of TechnologyHohhot 010051China College of Engineering University of Jinan Quancheng CollegeYantai 265600China

In this paper,we investigate the reverse order law for Drazin inverse of three bound-ed linear operators under some commutation ***,the Drazin invertibility of sum is also obtained for two bounded linear operators and... 详细信息

关键词： Drazin inverse reverse order law space decomposition

Statistical properties of ideal photons in a two-dimensional dye-filled spherical cap cavity

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Chinese Physics B 2024年第10期33卷 258-268页

作者： Ze cheng School of Physics Huazhong University of Science and TechnologyWuhan 430074China

Within the framework of quantum statistical mechanics,we have proposed an exact analytical solution to the problemof Bose-Einstein condensation(BEC)of harmonically trapped two-dimensional(2D)ideal *** utilize this analyticalsolution to investigate the statistical properties of ideal photons in a 2D dye-filled spherical cap *** resultsof numerical calculation of the analytical solution agree completely with the foregoing experimental results in the BEC ofharmonically trapped 2D ideal *** analytical expressions of the critical temperature and the condensate fractionare derived in the thermodynamic *** is found that the 2D critical photon number is larger than the one-dimensional(1D)critical photon number by two orders of *** spectral radiance of a 2D spherical cap cavity has a sharppeak at the frequency of the cavity cutoff when the photon number exceeds the critical value determined by a temperature.

关键词： rigorous results in statistical mechanics Bose-Einstein condensation 2D photons

Analysis of multi-objective optimisation method for main insulation structure configuration scheme of valve-side winding of ultra-high voltage converter transformer considering multi-field coupling

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High Voltage 2024年第2期9卷 296-308页

作者： lijun Yang Zhidong cheng li cheng Ruijin liao State Key laboratory of Power Transmission Equipment Technology School of Electrical EngineeringChongqing UniversityChongqingChina

Because DC conductivities of oil-paper materials can be easily affected by electric field and temperature,the electrical properties under electro-thermal coupling of oil-paper materials should be considered when optimising the insulation structure of valve-side winding of the converter *** on the finite element multi-physical field coupling simulation,the multi-objective optimisation of main insulation structure of valve-side winding is carried *** view of the high time consuming of multi-physical field calculation and the actual needs of an insulation structure optimisation,the Kriging method and technique for order preference by similarity to the ideal solution(TOPSIS)method are introduced,and combines them with NSGA-II to obtain a joint algorithm that can be used for the optimisation of insulation structure of the converter *** using the joint algorithm of multi-objective optimisation,the insulation structure configuration scheme of valve-side winding is *** can be seen from the experiment result that,on the one hand,the joint algorithm adopted can obtain the insulation structure configuration scheme that meets the design *** the other hand,when facing the configuration scheme optimisation under multi-field coupling,the computational time required by this method is only 0.15%of that required by original genetic algorithm.

关键词： converter insulation coupling

A synthesis of the Cretaceous wildfire record related to atmospheric oxygen levels?

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Journal of Palaeogeography 2024年第1期13卷 149-164页

作者： Da-Wei lü Wen-Xu Du Zhi-Hui Zhang Yuan Gao Tian-Tian Wang Jin-cheng Xu Ao-Cong Zhang cheng-Shan Wang Shandong Provincial Key laboratory of Depositional Mineralization and Sedimentary Minerals College of Earth Sciences and EngineeringShandong University of Science and TechnologyQingdao 266590Shandong ProvinceChina School of Earth Sciences and Resources China University of GeosciencesBejing 100083China Institute of Earth Sciences China University of Geosciences(Bejing)Beijing 100083China

The Cretaceous was a significant greenhouse period in Earth's history with higher atmospheric CO_(2) levels and temperatures than today. Although evidence of combustion has been widely described from the Cretaceous deposits, our understanding of the spatiotemporal diversification pattern and process of the Cretaceous wildfires is still limited. In this study, we comprehensively synthesize a total of 271 published Cretaceous wildfire occurrences based on the by-products of burning, including fossil charcoal, pyrogenic inertinite(fossil charcoal in coal), and pyrogenic polycyclic aromatic hydrocarbons(PAHs). Spatially, the dataset shows a distinctive distribution of reported wildfire evidence characterized by high concentration in the middle latitudinal areas of the Northern Hemisphere(30°N-60°N) over the Cretaceous. Temporally, an overall increasing trend of the reported wildfire data from the Early Cretaceous to the late Cretaceous is coincident with higher atmospheric O_(2) levels. However, the spatial and temporal patterns may result from many types of factors, such as taphonomy, preservation, and researcher biases, instead of a real picture of the Cretaceous wildfire evolution. To better understand the spatiotemporal diversification of the Cretaceous wildfire, more investigations on the record of wildfire occurrences during this period would be necessary in the future.

关键词： Wildfire Cretaceous Atmospheric oxygen Taphonomy Charcoal

Improved mass relations of mirror nuclei

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Nuclear Science and Techniques 2024年第9期35卷 178-185页

作者： cheng Xu Man Bao Department of Physics University of Shanghai for Science and TechnologyShanghai 200093China

In this study,we revisit the previous mass relations of mirror nuclei by considering 1/N-and 1/Z-dependent terms and the shell effect across a *** root-mean-squared deviation is 66 keV for 116 nuclei with neutron number N≥10,as com-pared with experimental data compiled in the AME2020 *** predicted mass excesses of 173 proton-rich nuclei,including 98 unknown nuclei,are tabulated in the Supplemental Material herein with competitive accuracy.

关键词： Nuclear mass Mirror nuclei Proton-rich nuclei