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Thermodynamic nature of black holes in coexistence region

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Science China(Physics,Mechanics & Astronomy) 2024年第5期67卷 27-32页

作者： Shao-Wen Wei Yu-Xiao Liu Lanzhou Center for theoretical Physics Key Laboratory of Theoretical Physics of Gansu Provinceand Key Laboratory of Quantum Theory and Applications of Mo ELanzhou UniversityLanzhou 730000China Institute of theoretical Physics&research Center of Gravitation Lanzhou UniversityLanzhou 730000China

Studying the system state of coexistence regions will peek into to reveal microscopic interactions between different phases of a thermodynamic ***,there is no effective method to study thermodynamic nature of the coexistence black hole regions for the failure of the equation of *** at these coexistence states,in this work,we develop a general approach by introducing two new ratio *** first one is the ratio of the horizon radii of the saturated coexistence small and large black holes,and the second one measures that of the small black hole molecule number to the total molecule *** demonstrate that the first parameter can serve as an order parameter to characterize the first-order phase *** study also shows that the black hole state in the coexistence region is uniquely determined by these two introduced parameters bounded between 0 and *** results are quite significant in the analytical study of phase transition and the microscopic nature of black hole in the coexistence regions.

关键词： transition. state. thermodynamic

Thermal stability improvement and microstructure optimization of high cobalt content Nd-Fe-B magnets via terbium grain boundary diffusion

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Journal of Rare Earths 2024年第8期42卷 1531-1538,I0004页

作者： Jiyuan Xu Ruiyang Meng Jing Liu Jiateng Zhang Rui Han Yikun Fang Shengzhi Dong Wei Li division of Functional Materials research Central Iron and Steel Research InstituteBeijing100081China

The substitution of Fe by Co in the 2:14:1 phase is an effective method to increase the Curie temperature and enhance the thermal stability of the Nd-Fe-B ***,the accumulation of Co ele ment at the grain boundaries(GBs) changes the GBs from nonmagnetic to ferromagnetic and causes the thinlayer GBs to become rare,In this paper,the method of diffusing Tb element was chosen to improve the microstructure and temperature stability of high-Co *** original sintered Nd_(28.5)Dy_(3)-CO_(x)e_(bal)M_(0.6)B_(i)(x=0,6 wt%,12 wt%;M = Cu,Al,Zr) magnets with different Co contents were diffused with Tb by grain boundary diffusion(GBD).After GBD,high-Co magnets exhibit more continuously distributed thin-layer GBs,and their thermal stability is significantly *** high-Co magnets(x=6 wt%),the absolute value of the temperature coefficient of coercivity decreases from 0.603%/K to0.508%/K in the temperature range of 293-413 K,that of remanence decreases from 0.099%/K to 0.091%/K,and the coercivity increases from 18.44 to 25.04 *** electron microscopy(TEM)characterization reveals that there are both the 1:2 phase and the amorphous phase in the high-Co magnet before and after GBD,EDS elemental analysis shows that Tb element is more likely to preferentially replace the rare earth elements in the 2:14:1 main phase than in the 1:2 phase and the amorphous *** concentration of Tb at the edge of the main phase is much higher than that in the 1:2phase and amorphous phase,which is beneficial to the improvement of the *** preferential replacement of Tb elements at the edge of the 2:14:1 phase and thin-layer GBs with a more continuous distribution are synergistically responsible for improving the thermal stability of high-Co *** study indicates that GBD is an effective method to improve the microstructure and thermal stability of high-Co magnets.

关键词： Nd-Fe-B magnets Coercivity Grain boundary diffusion Thermal stability Micro structure Rare earths

Recent research in mechanical properties of geopolymer-based ultrahigh-performance concrete:A review

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Defence Technology（防务技术） 2024年第2期32卷 67-88页

作者： G.Murali division of research&Innovation Uttaranchal UniversityDehradun 248007India

Due to the growing need for sustainable and ultra-high-strength construction materials,scientists have created an innovative ultra-high-performance concrete called Geopolymer based ultra-highperformance concrete(GUHPC).Besides,in the last few decades,there have been a lot of explosions and ballistic attacks around the world,which have killed many civilians and fighters in border *** this context,this article reviews the fresh state and mechanical properties of ***,the ingredients of GUHPC and fresh properties such as setting time and flowability are briefly ***,the review of compressive strength,flexure strength,tensile strength and modulus of elasticity of fibrous ***,the blast and projectile impact resistance performance was ***,the microstructural characteristics were reviewed using the scanning electron microscope and X-ray Powder *** review outcome reveals that the mechanical properties were increased when 30%silica fume was added to a higher dose of steel fibre to improve the microstructure of *** is hypothesized that the brittleness of GUHPC was mitigated by adding 1.5%steel fibre reinforcement,which played a role in the decrease of contact explosion cratering and *** the need for cement in GUHPC was a key factor in the review,indicating a promising potential for lowering carbon ***,GUHPC research is still in its early stages,so more study is required before its full potential can be utilized.

关键词： Mechanical properties Blast Projectile impact Fibre Geopolymer Silica fume Alkaline activators

A Novel Prescribed-Performance Path-Following Problem for Non-Holonomic Vehicles

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IEEE/CAA Journal of Automatica Sinica 2024年第6期11卷 1476-1484页

作者： Zirui Chen Jingchuan Tang Zongyu Zuo Seventh research division Beihang University(BUAA)Beijing 100191China IEEE

The issue of achieving prescribed-performance path following in robotics is addressed in this paper,where the aim is to ensure that a desired path within a specified region is accu-rately converged to by the controlled *** this context,a novel form of the prescribed performance guiding vector field is introduced,accompanied by a prescribed-time sliding mode con-trol ***,the interdependence among the pre-scribed parameters is *** validate the effectiveness of the proposed method,numerical simulations are presented to demonstrate the efficacy of the approach.

关键词： Guiding vector field non-holonomic vehicle path following prescribed performance sliding mode control

High-performance anisotropic SmCo-based magnet with novel microstructure

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Journal of Rare Earths 2024年第8期42卷 1539-1545,I0005页

作者： Yingchang Li Zicao Xing Nengjun Yu Zesong Ren Minxiang Pan Qiong Wu Hongliang Ge Minggang Zhu Wei Li College of Materials and Chemistry China jiliang UniversityHangzhou 310018China division of Functional Materials research Central Iron and Steel Research InstituteBeijing 100081China

A novel micro structure of magnetically anisotropic Sm Co-based magnet with high-performance is *** magnet consists of SmCo_(7)-H(TbCu_(7)-hexagonal type),Sm_(2)Co_(17)-H(Th_(2)Ni_(17)-hexagonal type)and SmCo_(3)-R(SmCo_(3)-rhombohedral type)*** maximum magnetic energy product of the magnet is 231.69 kj/m^(3),and the intrinsic coercivity is 1005.47 kA/*** outstanding intrinsic coercivity temperature coefficient(β)of-0.125%/K between 298 and 773 K is obtained,which is very close to theβof commercial high-temperature Sm_(2)Co_(17)-based sintered *** initial magnetization curve indicates that the coercivity mechanism is controlled by a domain wall pinning *** SmCo_(3)-R lamellar phase may be a potential pinning center or self-pinning *** microstructure of the magnet is different from that of any previous SmCo-based *** findings provide a new idea for preparing high-performance SmCo-based permanent magnets.

关键词： Rare earths Permanent magnet Composite magnet Melt-spinning Microstructure

Diagnostic and prognostic performances of GALAD score in staging and 1-year mortality of hepatocellular carcinoma: A prospective study

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World Journal of Gastroenterology 2024年第17期30卷 2343-2353页

作者： Oraphan Jitpraphawan Witchakorn Ruamtawee Mala Treewatchareekorn Supatsri Sethasine division of Gastroenterology and Hepatology Department of MedicineNavamindradhiraj UniversityDusit 10300BangkokThailand Clinical research Center Research Facilitation DivisionNavamindradhiraj UniversityDusit 10300BangkokThailand division of Clinical Chemistry and Immunology Navamindradhiraj UniversityDusit 10300BangkokThailand

BACKGROUND The GALAD score has improved early hepatocellular carcinoma(HCC)detection *** role of the GALAD score in staging and predicting tumor characteristics or clinical outcome of HCC remains of particular *** To determine the diagnostic/prognostic performances of the GALAD score at various phases of initial diagnosis,tumor features,and 1-year mortality of HCC and compare the performance of the GALAD score with those of other serum *** This prospective,diagnostic/prognostic study was conducted among patients with newly diagnosed HCC at the liver center of Vajira *** patients had HCC staging allocation using the Barcelona Clinic Liver Cancer(BCLC)***,HCC etiology,and HCC features were *** and the GALAD score were obtained at *** performance of the GALAD score and biomarkers were prospectively *** Exactly 115 individuals were diagnosed with *** GALAD score increased with disease *** BCLC-0/A and BCLC-B/C/D,the GALAD score predicted HCC staging with an area under the curve(AUC)of 0.868(95%CI:0.80–0.93).For identifying the curative HCC,the AUC of GALAD score was significantly higher than that of Alpha-fetoprotein(AFP)(0.753)and Lens culinaris agglutinin-reactive fraction of AFP-L3(0.706),and as good as that of Protein induced by vitamin K absence-II(PIVKA-II)(0.897).For detecting aggressive features,the GALAD score gave an AUC of 0.839(95%CI:0.75–0.92)and significantly outperformed compared to that of AFP(0.761)and AFP-L3(0.697),with a trend of superiority to that of PIVKA-II(0.772).The performance to predict 1-year mortality of GALAD score(AUC:0.711,95%CI:0.60–0.82)was better than that of AFP(0.541)and as good as that of PIVKA-II(0.736).The optimal cutoff value of GALAD score was≥6.83,with a specificity of 72.63%for exhibiting substantial reduction in the 1-year *** The GALAD model can diagnose HCC at the curative stage,includin

关键词： Alpha-fetoprotein Barcelona clinic liver cancer GALAD score Hepatocellular carcinoma Lens culinaris agglutinin-reactive fraction of alpha-fetoprotein Protein induced by vitamin K absence-II

Advances in DNA methylation and its role in cytoplasmic male sterility in higher plants

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Journal of Integrative Agriculture 2024年第1期23卷 1-19页

作者： Atiqur Rahman Hasan Sofiur Rahman Shakil Uddin Naima Sultana Shirin Akhter Ujjal Kumar Nath Shamsun Nahar Begum Mazadul Islam Afroz Naznin Nurul Amin Sharif Ahmed Akbar Hossain Department of Genetics and Plant Breeding Bangladesh Agricultural UniversityMymensingh 2202Bangladesh Plant Breeding division Bangladesh Institute of Nuclear AgricultureMymensingh 2202Bangladesh Tuber Crop research Centre Bangladesh Agricultural Research Institute(BARI)Joydebpur 1701Bangladesh Horticulture research Centre Bangladesh Agricultural Research Institute(BARI)Joydebpur 1701Bangladesh Biotechnology division Bangladesh Agricultural Research Institute(BARI)Joydebpur 1701Bangladesh International Rice research Institute Bangladesh OfficeDhaka 1213Bangladesh division of Soil Science Bangladesh Wheat and Maize Research InstituteDinajpur 5200Bangladesh

The impact of epigenetic modifications like DNA methylation on plant phenotypes has expanded the possibilities for crop *** methylation plays a part in the regulation of both the chromatin structure and gene expression,and the enzyme involved,DNA methyltransferase,executes the methylation process within the plant *** regulating crucial biological pathways,epigenetic changes actively contribute to the creation of the ***,epigenome editing may assist in overcoming some of the drawbacks of genome editing,which can have minor off-target consequences and merely facilitate the loss of a gene’s *** drawbacks include gene knockout,which can have such off-target *** review provides examples of several molecular characteristics of DNA methylation,as well as some plant physiological processes that are impacted by these epigenetic changes in the *** also discuss how DNA alterations might be used to improve crops and meet the demands of sustainable and environmentally-friendly farming.

关键词： DNA methylation epigenetics CMS male sterility chromatin architecture gene expression higher plants

Primordial black holes and curvature perturbations from false vacuum islands

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Science China(Physics,Mechanics & Astronomy) 2024年第9期67卷 58-72页

作者： Rong-Gen Cai Yu-Shi Hao Shao-Jiang Wang School of Physical Science and Technology Ningbo UniversityNingbo 315211China CAS Key Laboratory of theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China Asia Pacific Center for theoretical Physics Pohang 37673Republic of Korea

Recently,much attention has been focused on the false vacuum islands that are flooded by an expanding ocean of true-vacuum bubbles slightly later than most of the other parts of the *** delayed decay regions will accumulate locally larger vacuum energy density by staying in the false vacuum longer than those already transited into the true vacuum.A false vacuum island with thus acquired density contrast of a super-horizon size will evolve locally from radiation dominance to vacuum dominance,creating a local baby Universe that can be regarded effectively as a local closed *** such density contrasts of super-horizon sizes can ever grow large enough to exceed the threshold of gravitational collapse,primordial black holes will form similar to those collapsing curvature perturbations on super-horizon scales induced by small-scale enhancements during *** not,such density contrasts can still induce curvature perturbations potentially observable *** this paper,we revisit and elaborate on the generations of primordial black holes and curvature perturbations from delayed-decayed false vacuum islands during asynchronous first-order phase transitions with fitting formulas convenient for future model-independent studies.

关键词： first-order phase transitions primordial black holes curvature perturbations

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Consistency between domain wall oscillation modes and spin wave modes in nanostrips

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Chinese Physics B 2024年第6期33卷 511-516页

作者：董新伟吴振江 Department of Physics and Institute of theoretical Physics and Astrophysics Xiamen UniversityXiamen 361005China

Investigations on domain wall(DW) and spin wave(SW) modes in a series of nanostrips with different widths and thicknesses have been carried out using micromagnetic simulation. The simulation results show that the frequencies of SW modes and the corresponding DW modes are consistent with each other if they have the same node number along the width direction. This consistency is more pronounced in wide and thin nanostrips, favoring the DW motion driven by *** analysis of the moving behavior of a DW driven by SWs is also carried out. The average DW speed can reach a larger value of ~ 140 m/s under two different SW sources. We argue that this study is very meaningful for the potential application of DW motion driven by SWs.

关键词： micromagnetic simulation domain wall spin wave