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Exploring the effect of cooling rate on non-isothermal crystallization of copolymer polypropylene by fast scanning calorimetry

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China Foundry 2024年第4期21卷 379-386页

作者： Yang Liao Ye-yuan Hu Kosuke ikeda Ryoji okabe Rui-fen Wu Ryota ozaki Qing-yan Xu Key Laboratory for Advanced Materials Processing Technology School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China Composite Laboratory Research&Innovation Center Mitsubishi Heavy Industries Ltd.Nagasaki 8510392Japan

Polypropylene is commonly used as a binder for ceramic injection molding,and rapid cooling is often encountered during ***,the crystallization behavior of polypropylene shows a strong dependence on cooling rate due to its semi-crystalline ***,the influence of cooling rate on the quality of final product cannot be *** this study,the fast differential scanning calorimetry(FSC)test was performed to study the influence of cooling rate on the non-isothermal crystallization behavior and non-isothermal crystallization kinetics of a copolymer polypropylene(PP BC03B).The results show that the crystallization temperatures and crystallinity decrease as the cooling rate *** addition,two exothermic peaks occur when cooling rate ranges from 30 to 300 K·s^(-1),indicating the formation of another crystal ***,ozawa and Mo equations were used to explore the non-isothermal crystallization kinetics,and it can be concluded that the Mo method is suitable for this study.

关键词： cooling rate crystallization temperature crystallinity non-isothermal crystallization kinetics FSC copolymer polypropylene

Stability analysis of a time-delayed Van der Pol–Helmholtz–Duffing oscillator in fractal space with a non-perturbative approach

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Communications in Theoretical Physics 2024年第4期76卷 22-31页

作者： Yusry o El-Dib Department of Mathematics Faculty of EducationAin Shams UniversityRoxyCairoEgypt

The time-delayed fractal Van der Pol–Helmholtz–Duffing(VPHD)oscillator is the subject of this paper,which explores its mechanisms and highlights its stability *** time-delayed technologies are currently garnering significant attention,the focus of this research remains crucially relevant.A non-perturbative approach is employed to refine and set the stage for the system under *** innovative methodologies introduced yield an equivalent linear differential equation,mirroring the inherent nonlinearities of the ***,the incorporation of quadratic nonlinearity into the frequency formula represents a cutting-edge *** analytical solution's validity is corroborated using a numerical *** conditions are ascertained through the residual Galerkin ***,it is observed that the delay parameter,in the context of the fractal system,reverses its stabilizing influence,impacting both the amplitude of delayed velocity and the *** analytical solution's precision is underscored by its close alignment with numerical ***,the study reveals that fractal characteristics emulate damping *** its applicability across diverse nonlinear dynamical systems,this non-perturbative approach emerges as a promising avenue for future research.

关键词： Van der Pol-Helmholtz-Duffing oscillator fractal space time-delay non-perturbative approach stability analysis El-Dib's frequency formula

Valorization of Tree Bark-Derived Suberin in Applications for the Bio-Based Composites Industry–A Recent Review

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Journal of Renewable Materials 2024年第6期12卷 1029-1042页

作者： Aleksandra Jeżo Institute of Wood Sciences and Furniture SGGWNowoursynowska St.159Warsaw02-776Poland

Bark extracts are sustainable sources of biopolymers and hold great promise for replacing fossil fuel-based polymers,for example,in wood-based *** addition to primary and secondary metabolites,tree bark also contains suberin,which plays a major role in protecting the tree from environmental *** is a natural aliphatic-aromatic cross-linked polyester present in the cell walls of both normal and damaged external tissues,the main component of which are long-chain aliphatic *** main role as a plant ingredient is to protect against microbiological factors and water *** of the most important suberin monomers are suberin fatty acids,known for their hydrophobic and barrier ***,due to the diverse chemical composition of suberin,it is an attractive alternative to hydrocarbon-based *** its potential is recognized,it is not widely used in biocomposites technology,including wood-based composites and the polymer *** article will discuss the current knowledge about the potential of suberin and its components in biocomposites technology,which will include surface finishes,composite adhesives and polymer blends.

关键词： Suberin suberinic acids wood composites biocomposites biopolyester

Making topological protein links using enzymatic reactions

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National Science Review 2024年第3期11卷 50-51页

作者： Roger Castells-Graells Todd o.Yeates Department of Chemistry and Biochemistry University of California UCLA-DoE Institute for Genomics and Proteomics

Proteins are exceedingly complex molecules though, at their heart, they are essentially linear polymers. Pull at their ends and one obtains an extended backbone. While that is true in most cases, some natural proteins... 详细信息

关键词： DESIGN

A synthetic microbial community used as a bioinoculant can overcome rice production constraints in acid soils

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Science China(Life Sciences) 2024年第5期67卷 1085-1086页

作者： Maureen o’Callaghan Shengjing Shi Resilient Agriculture Group AgResearchLincolnChristcurch 8140New Zealand

A customised synthetic microbial community(SynCom)composed of carefully selected rhizosphere-competent bacterial strains improved rice growth,yield and resistance to soil acidity and Al toxicity.

关键词： soil soils rhizosphere

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Achievable hole concentration at room temperature as a function of Mg concentration for MoCVD-grown p-GaN after sufficient annealing

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Journal of Semiconductors 2024年第8期45卷 67-73页

作者： Siyi Huang Masao.ikeda Feng Zhang Minglong Zhang Jianjun Zhu Shuming Zhang Jianping Liu School of Nano-Tech and Nano-Bionics University of Science and Technology of ChinaHefei 230026China Suzhou Institute of Nano-Tech and Nano-Bionics Chinese Academy of SciencesSuzhou 215123China Key Laboratory of Nanodevices and Applications Chinese Academy of SciencesSuzhou 215123China

Relationship between the hole concentration at room temperature and the Mg doping concentration in p-GaN grown by MoCVD after sufficient annealing was studied in this *** annealing conditions were applied to obtain sufficient activation for p-GaN samples with different Mg doping *** concentration,resistivity and mobility were characterized by room-temperature Hall *** Mg doping concentration and the residual impurities such as H,C,o and Si were measured by secondary ion mass spectroscopy,confirming negligible compensations by the *** hole concentration,resistivity and mobility data are presented as a function of Mg concentration,and are compared with literature *** appropriate curve relating the Mg doping concentration to the hole concentration is derived using a charge neutrality equation and the ionized-acceptor-density[N-(A)^(-)](cm^(−3))dependent ionization energy of Mg acceptor was determined asE_(A)^(Mg)=184−2.66×10^(−5)×[N_(A)^(-)]1/3 meV.

关键词： p-GaN hole concentration electrical properties annealing ionization energy

Harnessing the power of pericytes and hypoxia-inducible factor-1 to modulate stroke outcome

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Neural Regeneration Research 2024年第3期19卷 473-474页

作者： omolara o.ogunshola Chih-Chieh Tsao Institute of Veterinary Physiology Vetsuisse FacultyUniversity of ZurichZurichSwitzerland

The human brain has exceedingly high metabolic *** cerebral vasculature has the critical task of providing sufficient blood supply to meet this *** sudden interruption of blood flow to the brain,as observed during ischemic stroke,results in acute neurological injury with devastating consequences-a high rate of adult disability and *** stroke is thus a vascular disorder with a dramatic neurological *** is an urgent need for more effective disease management to combat stroke as current treatment paradigms,focusing on vascular recanalization and neuroprotection,have only limited clinical *** accumulating data suggests successful long-term neuroprotection is unlikely to be achievable without a functional microvascular network,strategies that reduce endothelial dysfunction could be ***,very recent evidence highlighted herein suggests protecting the humble pericyte may be a new approach to reaching this goal.

关键词： consequences exceeding herein

Mutations of voltage-gated sodium channel contribute to pyrethroid resistance in Panonychus citri

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Insect Science 2024年第3期31卷 803-816页

作者： Deng Pan Qiu-Juan Luo Andrias o.o'Reilly Guo-Rui Yuan Jin-Jun Wang Wei Dou Key Laboratory of Entomology and Pest Control Engineering College of Plant ProtectionAcademy of Agricultural SciencesSouthwest UniversityChongqingChina Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River(Ministry of Education) Academy of Agricultural SciencesSouthwest UniversityChongqingChina School of Biological and Environmental Sciences Liverpool John Moores UniversityLiverpoolUK

Insecticide resistance in Panonychus citri is a major obstacle to mite control in citrus *** insecticides are continually used to control mites in China,although resistance to pyrethroids has evolved in some ***,the resistance to the pyrethroid fenpropathrin was investigated and 7 out of 8 field-collected populations of P citri exhibited a high level of resistance,ranging from 171-fold to 15391-fold higher than the susceptible(SS)comparison *** voltage-gated sodium channel(VGSC)mutations were identified in the tested populations:L1031V,F1747L,and *** sequencing was used to evaluate the frequency of these mutations in the 19 field populations.L1031V and F1751I were present in all populations at frequencies of 11.6%-82.1%and 0.5%-31.8%,respectively,whereas the F1747L mutation was only present in 12 populations from Chongqing,Sichuan,Guangxi,and Yunnan *** of these mutations singly or in combination into transgenic flies significantly increased their resistance to fenpropathrin and these flies also exhibited reduced mortality after exposure to the pyrethroids permethrin andβ-*** citri VGSC homology modeling and ligand docking indicate that F1747 and F1751 form direct binding contacts with pyrethroids,which are lost with mutation,whereas L1031 mutation may diminish pyrethroid effects through an allosteric ***,the results provide molecular markers for monitoring pest resistance to pyrethroids and offer new insights into the basis of pyrethroid actions on sodium channels.

关键词： amplicon sequencing kdr mutation molecular docking Panonychus citri pyrethroid resistance transgenic flies

Evaluation of formation susceptibility and sand production potential in an offshore field,Niger Delta Basin,Nigeria

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Energy Geoscience 2024年第1期5卷 1-11页

作者： David o.Ubuara Yinka A.olayinka Godwin o.Emujakporue Geoffrey C.Soronnadi-ononiwu Department of Geology University of Port HarcourtNigeria Mease Energy Nigeria Limited Port HarcourtNigeria Department of Geology University of IbadanNigeria Department of Physics University of Port HarcourtNigeria

Wellbore instability and sand production are all common challenges in the Niger Delta oil province,resulting in high drilling and production cost as well as damage to oil *** vulnerability of lithologic formations to wellbore instability and resultant sand production is investigated in the four delineated reservoirs of the“Areo”field,western part of Niger Delta *** foundation for establishing the geomechanical properties in this study was a 1-dimensional mechanical earth model,using gamma ray(GR),density(RHoB),compressional slowness(DTC),and shear slowness(DTS)*** the Areo oil field,two wells(well 001 and well 002)were *** evaluated formations are still primarily composed of compacted shale and unconsolidated sandstone,with reservoir sand units exhibiting lower elastic and rock strength properties than shale *** compressibility and porosity make sand more brittle,while low compressibility and porosity make shale stiffer due to high *** maximum force that can be applied to a shale unit without causing it to fail is 17.23 MPa,which is the maximum average rock strength of the *** means that shale requires more vertical stress or pressure than sand does in order to deform it(15.06 MPa).The three sand prediction approaches used in the analysis of sand production predictions have cut-off values that are higher than the average values of the *** Schlumberger sand production index method(S/I)indicates that the reservoir has potential for sand influx in the two wells,with the average of the four reservoirs studied in wells 001 and 002 being 1.551012 psi and 1.141012 psi ***,when a formation's sand production index is less than 1.241012 psi,as it is in this study,the formation is likely to produce *** findings support the notion that the defined sandstone units are highly unconsolidated and have a high potential for producing sands;therefore,sand control techniques must be factored in

关键词： Wireline log Stress Geo-mechanicanical characterization Sand prediction Niger delta