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Unique Ergodicity for Zero-entropy Dynamical Systems with the Approximate Product Property

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Acta Mathematica Sinica,English Series 2021年第2期37卷 362-376页

作者： peng sun China Economics and Management Academy Central University of Finance and EconomicsBeijing 100081P.R.China

We show that for every topological dynamical system with the approximate product property, zero topological entropy is equivalent to unique ergodicity. Equivalence of minimality is also proved under a slightly stronger condition. Moreover, we show that unique ergodicity implies the approximate product property if the system has periodic points.

关键词： Approximate product property unique ergodicity topological entropy ergodic measure minimality specification gluing orbit interval map periodic points

Target versus sub-target dose of renin–angiotensin system inhibitors on survival in elderly patients with heart failure with reduced ejection fraction: a systematic review and meta-analysis

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Journal of Geriatric Cardiology 2023年第6期20卷 469-478页

作者： Long-Kun sun Jing KONG Xiao-Wei YANG Jing WANG peng-fei ZHANG The Key Laboratory of Cardiovascular Remodeling and Function Research Chinese Ministry of EducationChinese National Health Commission and Chinese Academy of Medical SciencesThe State and Shandong Province Joint Key Laboratory of Translational Cardiovascular MedicineDepartment of CardiologyQilu HospitalCheeloo College of MedicineShandong UniversityJinanChina

BACKGROUND The efficiency of the target versus sub-target dose of renin–angiotensin system inhibitors(RASIs)in elderly patients with heart failure(HF)with reduced ejection fraction(HErEF)remains *** PubMed,Embase,and the Cochrane Central Register of Controlled Trials were searched from database inception through March 2022 for randomized controlled trials(RCTs)and observational studies considering the effect of the target versus sub-target dose of RASIs on survival in elderly patients(≥60 years)with *** primary outcome was all-cause *** secondary outcomes were cardiac mortality,HF hospitalization,and the composite endpoint of mortality or HF hospitalization.A meta-analysis was conducted to generate combined hazard ratio(HR)and 95%*** Seven studies(two RCTs and five observational studies)enrolling 16,634 patients were included.A pooled analysis suggested that the target versus sub-target dose of RASIs led to lower rates of all-cause mortality(HR=0.92,95%CI:0.87–0.98,I2=21%)and cardiac mortality(HR=0.93,95%CI:0.85–1.00,I2=15%)but not reduced rates of HF hospitalization(HR=0.94,95%CI:0.88–1.01,I2=0)and the composite endpoint(HR=1.03,95%CI:0.91–1.15,I2=51%).However,the target dose of RASIs was associated with a similar primary outcome(HR=0.85,95%CI:0.64–1.14,I2=0)in a subgroup of very elderly patients>75 years of *** Our analysis suggests that the target dose of RASIs has a better survival benefit in elderly patients with HFrEF compared to the sub-target dose of ***,the sub-target dose of RASIs is associated with a similar mortality rate in very elderly patients>75 years of *** high-quality and adequately powered RCTs are warranted.

关键词： patients analysis fraction

A Novel Fractional Plastic Damage Model for Quasi-brittle Materials

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Acta Mechanica Solida Sinica 2021年第5期34卷 706-717页

作者： peng-fei Qu Qi-Zhi Zhu Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering Hohai UniversityNanjing210098China College of Civil and Transportation Engineering Hohai UniversityNanjing210098China

In this work,a novel constitutive model is developed within the framework of fractional plasticity to delineate the coupling between inelastic deformation and damage of quasi-brittle *** with the common challenge of determining plastic flow direction,we resort herein to the Riemann–Liouville definition of fractional derivatives,instead of introducing an additional plastic *** pre-peak hardening behavior is described using an exponential function,while the post-peak softening response is viewed as the consequence of material *** describing damage evolution,a damage criterion is constructed in terms of plastic volume dilation related to micro-crack *** is conducive to supply a new insight for describing the complex influence of the non-orthogonality of plastic flow on damage *** numerical applications,a semi-implicit return mapping algorithm is *** predictive performance of the model is evaluated by comparing numerical simulations with experimental data under various loading paths.

关键词： Quasi-brittle materials Fractional plasticity Damage Dilatancy Numerical algorithm

Numerical research on adverse effect of muzzle flow formed by muzzle brake considering secondary combustion

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Defence Technology（防务技术） 2021年第4期17卷 1178-1189页

作者： peng-fei Li Xiao-bing Zhang School of Energy and Power Engineering Nanjing University of Science and TechnologyNanjing210094PR China

The simulation of the artillery interior and intermediate ballistics problem is performed to investigate the influence of a gas dynamics device,muzzle brake,on the muzzle hazard phenomena,such as flash and blast *** correlation of the chemical reactions with the characteristics of the muzzle flow field is analyzed by the simulation for a further understanding of the secondary combustion phenomenon of the muzzle *** novel structure of muzzle flow caused by the muzzle brake is presented by the simultaneous solution of the interior ballistics model and multi-species Navier-Stokes equations in order to analyze the influence of the muzzle brake structure on the chemical *** secondary combustion of the muzzle flow due to the oxygen-supplement chemical reactions is obtained by the chemical reaction kinetic *** interaction of the blast waves released from the muzzle brake is illustrated in detail and the mechanism of the formation of muzzle flash is *** research provides a reference for the studies on the suppression of the muzzle flash.

关键词： Muzzle flow Muzzle brake Secondary combustion Chemical reaction

Control of Austenite Characteristics and Ferrite Formation Mechanism by Multiple-Cyclic Annealing in Quenching and Partitioning Steel

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Acta Metallurgica Sinica(English Letters) 2022年第7期35卷 1143-1156页

作者： fei peng Yunbo Xu Xingli Gu College of Materials Science and Engineering Hunan UniversityChangsha 410082China State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819China Technology Center of Angang Steel Co. Ltd.Anshan 114009China

Quenching and partitioning(Q&P)treatment is a novel method to produce advanced high strength steel with excellent mechanical *** this study,combination of multiple-cyclic annealing and Q&P process was compared with traditional cold-rolled Q&P steel to investigate the microstructural characteristics and austenite *** results showed that retained austenite in traditional Q&P sample was principally located in the exterior of austenite transformation products,while those in multiple-cyclic annealing samples were mainly distributed inside the transformation *** the increase in cyclic annealing number,both of austenite fraction and austenite carbon content increased,attributing to higher initial austenite carbon content and larger number of austenite/neighbored phase interface to act as carbon partitioning *** traditional Q&P sample,the deformed ferrite was recrystallized by sub-grain coalescence,while the austenite was newly nucleated and grew up during annealing *** a comparison,the ferrite in multiple-cycle annealing samples was formed by means of three routes:tempered martensite that completely recovered with retention of interior martensite variant,epitaxial ferrite that formed on basis of tempered martensite,ferrite that newly nucleated and grew up during the final annealing *** of lath martensite and twin martensite were formed as initial martensite and then tempered during partitioning process to precipitateεcarbide with C enrichment,Mn enrichment and homogeneous Si *** with the traditional cold-rolled Q&P steel,the Q&P specimens after multiple-cyclic annealing show smaller strength and much larger elongation,ascribing to the coarser microstructure and more efficient transformation induced plasticity(TRIP)effect deriving from retained austenite with high carbon content and larger volume *** application of double annealing treatment can optimize the mechanical properties of Q&P steel to

关键词： Quenching and partitioning Cyclic annealing Ferrite formation Retained austenite

Amine-Actuated Catalyst Switch for One-Pot Synthesis of Ether-Ester Type Block Copolymers

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Chinese Journal of Polymer Science 2024年第12期42卷 1925-1932,I0008页

作者： Hong Qiu peng-fei Zhang Jun-peng Zhao Faculty of Materials Science and Engineering South China University of TechnologyGuangzhou 510640China

Organocatalysis has shown special potency for simplifying the construction of complex polymer *** are reporting here a one-pot synthetic pathway using amine as a selectivity-switching agent in the two-component catalytic system consisting of triethylborane(Et_(3)B)and a phosphazene *** first modelled the interactions of a variety of amines with Et_(3)B by density functional theory *** results indicate that the aliphatic diamines comprising both primary and tertiary amino groups,capable of forming stable intramolecular hydrogen bonds,undergo the strongest complexation with Et_(3)***,experimental results demonstrate that the addition of such amines promptly actuates the in situ selectivity switch from Lewis pair-catalyzed ring-opening polymerization(ROP)of epoxide(propylene oxide,n-butylglycidyl ether,or glycidyl phenyl ether)to organobase-catalyzed ROP ofδ-valerolactone,allowing one-pot continuous synthesis of ether-ester type block *** thus exploited the noncovalent interaction between amine and Et_(3)B to refine the catalyst switch strategy by exempting it from loading of extra catalyst.

关键词： Ring-opening polmerization Block copolymers Organocatalysis

新会陈皮中4株糖苷酶高产菌的分离鉴定、益生特性及发酵效果分析

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食品工业科技 2025年第1期46卷 171-180页

作者：沈飞王庭雨孙辉吴振强华南理工大学生物科学与工程学院广东广州510006 江门市泛亚生物工程与健康研究院广东江门529000 江门市泛亚生物工程与健康产业有限公司广东江门529000 仲恺农业工程学院农业与生物学院广东广州510006

为扩充促进新会陈皮发酵陈化的益生菌种质资源,本研究从新会陈皮中分离鉴定出4株细菌,并对其产酶能力、益生特性、安全性以及发酵新会陈皮的效果进行了评价。4株细菌均属于芽孢杆菌属,其中菌株L7具有最高的产滤纸酶、羧甲基纤维素酶、β... 详细信息

为扩充促进新会陈皮发酵陈化的益生菌种质资源,本研究从新会陈皮中分离鉴定出4株细菌,并对其产酶能力、益生特性、安全性以及发酵新会陈皮的效果进行了评价。4株细菌均属于芽孢杆菌属,其中菌株L7具有最高的产滤纸酶、羧甲基纤维素酶、β-葡萄糖苷酶和果胶酶能力,酶活分别达到1.84、0.79、1.6和1.24 U/mL。所有菌株均能在胃肠道环境下良好的存活,具有较强的抑菌性和共聚集性,无溶血性,且对多种抗生素敏感,表现出良好的益生特性和安全性。L7发酵新会陈皮效果最佳。经L7发酵后,新会陈皮结合态黄酮组分被有效地转化成游离态形式释放,特别是橙皮苷、川陈皮素和桔皮素,较未发酵新会陈皮分别提高了34.8%、93.7%以及102.7%。此外,L7发酵后的新会陈皮表现出更强的抗氧化活性,这与其具有更高的柚皮素和橙皮素含量密切相关。本研究结果为新会陈皮健康产品的开发和加速陈化技术的建立提供了参考。

关键词：新会陈皮芽孢杆菌糖苷酶益生特性发酵效果

Structure instability forecasting and analysis of giant rock pillars in steeply dipping thick coal seams

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International Journal of Minerals,Metallurgy and Materials 2015年第12期22卷 1233-1244页

作者： Xing-ping Lai Huan sun peng-fei Shan Ming Cai Jian-tao Cao Feng Cui Energy School Xi’an University of Science and Technology Key Laboratory of Western Mines and Hazard Prevention (Ministry of Education of China) Bharti School of Engineering Laurentian University

Structure stability analysis of rock masses is essential for forecasting catastrophic structure failure in coal seam mining. Steeply dipping thick coal seams （SDTCS） are common in the Urumqi coalfield, and some dynamical hazards such as roof collapse and mining-induced seismicity occur frequently in the coal mines. The cause of these events is mainly structure instability in giant rock pillars sand- wiched between SDTCS. Developing methods to predict these events is important for safe mining in such a complex environment. This study focuses on understanding the structural mechanics model of a giant rock pillar and presents a viewpoint of the stability of a trend sphenoid fractured beam （TSFB）. Some stability index parameters such as failure surface dips were measured, and most dips were observed to be between 46° and 51°. We used a digital panoramic borehole monitoring system to measure the TSFB＇s height （△H）, which varied from 56.37 to 60.50 m. Next, FLAC^3D was used to model the distribution and evolution of vertical displacement in the giant rock pillars; the results confirmed the existence of a TSFB structure. Finally, we investigated the acoustic emission （AE） energy accumulation rate and observed that the rate commonly ranged from 20 to 40 kJ/min. The AE energy accumulation rate could be used to anticipate impeding seismic events related to structure failure. The results presented provide a useful approach for forecasting catastrophic events related to structure instability and for developing hazard prevention technology for mining in SDTCS.

关键词： coal mining structural instability rock pillars forecasting acoustic emission (AE) steeply dipping coal beds

Theoretical Studies on Reaction Mechanisms of HNCS with NH(X^3Σ)

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Chemical Research in Chinese Universities 2006年第5期22卷 635-638页

作者： LIU peng-jun ZHANG Lian-hua sun Hao CHANG Ying-fei WANG Rong-shun Chemistry Depatrment of Hainan Normal University Haikou 571158 P. R. China Institute of Functional Material Chemistry Faculty of ChemistryNortheast Normal University Changchun 130024 P. R. China

The reaction mechanisms of HNCS with NH（X^3∑ ） were theoretically investigated. The minimum energy paths （MEP） of the reaction were calculated by using the density functional theory（DFT） at the B3LYP/6-311 ＋＋ G^＊＊ level. The equilibrium structural parameters, the harmonic vibrational frequencies, the total energies, and the zeropoint energies（ZPE） of all the species were calculated. The single-point energies along the MEP were further refined at the QCISD（T）/6-311 ＋＋ G^＊＊ level. It was found that the mechanisms of the HNCS ＋ NH（X^3∑） reaction involve two channels producing the HNC ＋ HNS and the N2H2 ＋ CS products. Channel 1 plays a dominant role and the HNC ＋ HNS are the main preduets. The reaction is exothermie.

关键词： HNCS NH(X^3∑) Reaction mechanism Density functional theory(DFT)