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Critical Role of Ethylene-Propylene Block Copolymer in Impact Polypropylene Copolymer

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Chinese Journal of Polymer Science 2024年第3期42卷 344-351,I0007页

作者： Yu-Hui Tang Na Zhang wei Bao wei Jiang Yuan Lin Zhao-Hui Su State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefei 230026China

Ethylene-propylene block copolymer(EbP) is a vital component in impact polypropylene copolymer(IPC), yet its distribution in the multiphase composite material and how it influences the phase structure and the mechanical properties are not well understood. In this work,four IPCs were investigated by atomic force microscopy-infrared(AFM-IR) to assess the phase compositions in situ, based on which in conjunction with the chain microstructure information obtained ex situ the distributions of the copolymer components were derived for each alloy. For the IPCs whose EbP comprises long P and long E segments, the EbP fraction was found to phase separate from the rubber and the PP matrix to form the cores of the disperse particles with the E-P segmented copolymer(EsP). In contrast, in the IPC with EbP composed of long P and short E segments, the EbP fraction formed an outer shell for the rubber particles with the cores comprising the EsP alone, and this IPC, containing a lower E comonomer content than its counterpart, exhibited both better impact resistance and higher flexural modulus. These results clarify how the chain structure of EbP governs the phase morphology in IPC, which in turn impacts the properties of the composite material.

关键词： Impact polypropylene copolymers AFM-IR Ethylene-propylene block copolymers Core-shell rubber particles

Hawking-Page transition and the dual relations of anti-de Sitter black holes surrounded by dark energy in general dimensions

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Communications in Theoretical Physics 2024年第7期76卷 94-104页

作者： Zhang Xin Xu wei School of Mathematics and Physics China University of GeosciencesWuhan 430074China

Recently,a dual relation T_(0)(n+1)=T_(HP)(n)between the minimum temperature(T_(0)(n+1))black hole phase and the Hawking-Page transition(T_(HP)(n))black hole phase in two successive dimensions was introduced by wei et al(2020 ***.D10210411);this was reminiscent of the anti-de Sitter/conformal field theory(AdS/CFT)correspondence,as the Hawking-Page transition temperature could be treated as the temperature of the dual physical quantity on the boundary and the latter corresponds to that in the *** this paper,we discuss the Hawking-Page transition and the dual relations in Ads black holes surrounded by dark energy in general *** findings reveal the occurrence of the Hawking-Page transition between the thermal AdS radiation and thermodynamically stable large AdS black holes,in both the spacetime surrounded by phantom dark energy and the spacetime surrounded by quintessence dark *** discuss the effects of the phantom dark energy and quintessence dark energy on the Hawking-Page transition *** the dual relation in particular,it works well for the case of an AdS black holes surrounded by phantom dark *** the case of an Ads black hole surrounded by quintessence dark energy,the dual relation should be modified under an open assumption that the state parameter and the density parameter of the quintessence dark energy depend on the dimensions of the spacetime.

关键词： Hawking-Page transition dark energy black hole thermodynamics

Point defects in 2-D liquid crystals with a singular potential:Profiles and stability

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Science China Mathematics 2024年第11期67卷 2515-2540页

作者： Zhiyuan Geng wei Wang Basque Center for Applied Mathematics School of Mathematical Sciences Zhejiang University

We study radial symmetric point defects with degree k/2 in the 2-D disk or R2in the Q-tensor framework with a singular bulk energy,which is defined by Bingham ***,we obtain the existence of solutions for the profiles of radial symmetric point defects with degree k/2 in the 2-D disk or ***,we prove that the solution is stable for |k| = 1 and unstable for |k| > *** identities are derived and utilized throughout the proof of existence and stability/instability.

关键词： radial symmetric point defects singular bulk potential Bingham closure stability

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Insight into the Role of Isolated Gold Atoms-Ceria Conjunction in Catalyzing the Water-Gas Shift Reaction

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Chinese Journal of Chemistry 2024年第6期42卷 636-644页

作者： Xin-Pu Fu Hui-Zhao wei-wei Wang Chun-Jiang Jia Key Laboratory for Colloid and Interface Chemistry Key Laboratory of Special Aggregated MaterialsSchool of Chemistry and Chemical EngineeringShandong UniversityJinanShandong250100 China

As the promising catalysts for the water-gas shift(WGS)reaction,the activity of Au-CeO_(2) composites is susceptible to the aggregation size and electronic state of Au *** reports were extensively focused on the discrepancy between nonmetallic Au and metallic Au nanoparticles,whereas the understanding of the authentic role of the isolated Au atoms was ***,we investigated the catalytic behavior and structural information over two types of Au/CeO_(2) catalysts,in which the predominant conjunctions were isolated Au1-CeO_(2) and Aun-CeO_(2),*** on comprehensive characterizations,particularly by in-situ Raman and in-situ DRIFTS,we found that the isolated Au atoms were responsible for enhancing the reducibility of the CeO_(2) *** CO adsorption ability on the isolated Au sites was significantly inferior to clustered Au atoms,especially at relatively high temperatures(>200°C).As a result,the boosted O vacancy on the isolated Au1-CeO_(2) conjunctions could improve the H2O activation ability for the Au-CeO_(2) catalysts and demonstrate a comparable activity to the clustered Aun-CeO_(2) *** work might deepen understanding of the catalytic function for the isolated Au1 site within Au/CeO_(2) systems while catalyzing the WGS reaction.

关键词： Isolated Au atoms Ceria-based catalysts Water-gas shift reaction Defect Adsorption

A Feature Selection Method Based on Hybrid Dung Beetle Optimization Algorithm and Slap Swarm Algorithm

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Computers, Materials & Continua 2024年第8期80卷 2979-3000页

作者： wei Liu Tengteng Ren School of Information Science and Engineering Shenyang Ligong UniversityShenyang110158China

Feature Selection(FS)is a key pre-processing step in pattern recognition and data mining tasks,which can effectively avoid the impact of irrelevant and redundant features on the performance of classification *** recent years,meta-heuristic algorithms have been widely used in FS problems,so a Hybrid Binary Chaotic Salp Swarm Dung Beetle Optimization(HBCSSDBO)algorithm is proposed in this paper to improve the effect of *** this hybrid algorithm,the original continuous optimization algorithm is converted into binary form by the S-type transfer function and applied to the FS *** combining the K nearest neighbor(KNN)classifier,the comparative experiments for FS are carried out between the proposed method and four advanced meta-heuristic algorithms on 16 UCI(University of California,Irvine)*** evaluation metrics such as average adaptation,average prediction accuracy,and average running time are chosen to judge and compare the *** selected dataset is also discussed by categorizing it into three dimensions:high,medium,and low *** results show that the HBCSSDBO feature selection method has the ability to obtain a good subset of features while maintaining high classification accuracy,shows better optimization *** addition,the results of statistical tests confirm the significant validity of the method.

关键词： Feature selection dung beetle optimization KNN transfer function HBCSSDBO

Dynamic Measurement of Intracellular pH Based on Bioluminescent Bacteria

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Chemical Research in Chinese Universities 2024年第2期40卷 287-292页

作者： LI Yaohua WANG wei State Key Laboratory of Analytical Chemistry for Life Science School of Chemistry and Chemical EngineeringChemBIC(Chemistry and Biomedicine Innovation Center)Nanjing UniversityNanjing210023P.R.China

Intracellular pH(pHi)is a fundamental indicator of cellular physiological state,regulating cellular state and function,and has important research *** various probes for measuring intracellular pH were available,it is challenging to reflect pHi in real-time and reversible ***,we developed a whole-cell bioluminescent(BL)probe based on wild type BL bacteria,photobacterium phosphoreum(***),to determine and image *** dependence of BL intensity of *** on pH values of culture solutions was *** was found that BL intensity could respond to the change of pH values rapidly and *** further revealed that *** maintained pH homeostasis in the extracellular pH(pHe)within the range of 5.0–7.0,while intracellular pH homeostasis was destroyed at the alkaline *** method opens up the enormous potential of BL bacteria as an alternative to fluorescence for monitoring and imaging pHi.

关键词： Bioluminescence P.phosphoreum Intracellular pH Cell imaging

Collectively induced transparency and absorption in waveguide quantum electrodynamics with Bragg atom arrays

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Communications in Theoretical Physics 2024年第8期76卷 19-28页

作者： Haolei Cheng wei Nie Center for Joint Quantum Studies and Department of Physics School of ScienceTianjin UniversityTianjin 300350China Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology Tianjin UniversityTianjin 300350China

Collective quantum states, such as subradiant and superradiant states, are useful for controlling optical responses in many-body quantum systems. In this work, we study novel collective quantum phenomena in waveguide-coupled Bragg atom arrays with inhomogeneous *** atoms without free-space dissipation, collectively induced transparency is produced by destructive quantum interference between subradiant and superradiant states. In a large Bragg atom array, multi-frequency photon transparency can be obtained by considering atoms with different frequencies. Interestingly, we find collectively induced absorption(CIA) by studying the influence of free-space dissipation on photon transport. Tunable atomic frequencies nontrivially modify decay rates of subradiant states. When the decay rate of a subradiant state equals to the free-space dissipation, photon absorption can reach a limit at a certain frequency. In other words, photon absorption is enhanced with low free-space dissipation, distinct from previous photon detection schemes. We also show multi-frequency CIA by properly adjusting atomic frequencies. Our work presents a way to manipulate collective quantum states and exotic optical properties in waveguide quantum electrodynamics(QED) systems.

关键词： waveguide quantum electrodynamics collective quantum states photon absorption Bragg atom array

Recognition and rejection of foreign eggs of different colors in Barn Swallows

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Avian Research 2024年第3期15卷 374-378页

作者： Kui Yan wei Liang Ministry of Education Key Laboratory for Ecology of Tropical Islands Key Laboratory of Tropical Animal and Plant Ecology of Hainan ProvinceCollege of Life SciencesHainan Normal UniversityHaikou571158China

Brood parasitic birds lay eggs in the nests of other birds,and the parasitized hosts can reduce the cost of raising unrelated offspring through the recognition of parasitic *** can adopt vision-based cognitive mechanisms to recognize foreign eggs by comparing the colors of foreign and host ***,there is currently no uniform conclusion as to whether this comparison involves the single or multiple threshold decision *** this study,we tested both hypotheses by adding model eggs of different colors to the nests of Barn Swallows(Hirundo rustica)of two geographical populations breeding in Hainan and Heilongjiang Provinces in *** showed that Barn Swallows rejected more white model eggs(moderate mimetic to their own eggs)and blue model eggs(highly non-mimetic eggs with shorter reflectance spectrum)than red model eggs(highly nonmimetic eggs with longer reflectance spectrum).There was no difference in the rejection rate of model eggs between the two populations of Barn Swallows,and clutch size was not a factor affecting egg *** results are consistent with the single rejection threshold *** study provides strong experimental evidence that the color of model eggs can has an important effect on egg recognition in Barn Swallows,opening up new avenues to uncover the evolution of cuckoo egg mimicry and explore the cognitive mechanisms underlying the visual recognition of foreign eggs by hosts.

关键词： Barn Swallow Egg color Hirundo rustica Multiple rejection threshold Single rejection threshold Visual recognition system

New low-rank optimization model and algorithms for spectral compressed sensing

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Science China Mathematics 2024年第10期67卷 2409-2432页

作者： wei Zeng Chuanju Xu School of Mathematical Sciences and Fujian Provincial Key Laboratory of Mathematical Modeling and High Performance Scienti c Computing Xiamen UniversityXiamen 361005China

In this paper, we investigate the recovery of an undamped spectrally sparse signal and its spectral components from a set of regularly spaced samples within the framework of spectral compressed sensing and super-resolution. We show that the existing Hankel-based optimization methods suffer from the fundamental limitation that the prior knowledge of undampedness cannot be exploited. We propose a new low-rank optimization model partially inspired by forward-backward processing for line spectral estimation and show its capability to restrict the spectral poles to the unit circle. We present convex relaxation approaches with the model and show their provable accuracy and robustness to bounded and sparse noise. All our results are generalized from one-dimensional to arbitrary-dimensional spectral compressed sensing. Numerical simulations are provided to corroborate our analysis and show the efficiency of our model and the advantageous performance of our approach in terms of accuracy and resolution compared with the state-of-the-art Hankel and atomic norm methods.

关键词： subdi usion equations variable transformation -Sobolev spaces well-posedness space-time Galerkin spectral method error estimate fast algorithm