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苯并环丁烯封端的液晶聚酯酰亚胺的制备与性能

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高分子学报 2024年第9期55卷 1241-1250页

作者：吴文虎李洋余华光刘继延黄祚刚刘学清江汉大学光电材料与技术学院光电化学材料与器件教育部重点实验室武汉430056

设计并合成了具有苯并环丁烯(BCB)结构的含酚羟基的酰亚胺2-(二环[4.2.0]辛-1,3,5-三烯-3-基)-5-羟基-1H-异吲哚-1,3(2H)-二酮(BCB-HP)和含芳酸的酰亚胺2,3-二氢-1,3-二氧-2-(二环[4.2.0]辛-1,3,5-三烯-3-基)-1H-异吲哚-5-羧酸(BCB-CP),与4-羟基苯甲酸(4-HBA)、6-羟基-2-萘甲酸(HNA)和N-(3-羧基苯基)-4-羟基邻苯二甲酰亚胺(3-CHP)通过溶液缩聚共聚合成了液晶聚酯酰亚胺(LCPEI).与不含热活性BCB基团的LCPEI比较,BCB型LCPEI具有更好的溶解度、较低的熔融温度(Tm=200℃),以及较高的玻璃化转变温度(Tg=149℃),具有良好的加工和应用潜力.LCPEI-22-BCB(含22 mol%CHP)制备的薄膜相较于LCPEI-22,弹性模量更高,介电常数相近(Dk=3.364@10 GHz),介电损耗更低(Df=0.0019),具有作为挠性覆铜板材料的应用前景.

关键词：液晶聚酯聚酯酰亚胺苯并环丁烯低介电常数

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Asymmetric Drying and Wetting Trends in Eastern and Western China

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Advances in Atmospheric Sciences 2024年第2期41卷 221-232页

作者： wen wu Fei JI Shujuan hu Yongli HE College of Atmospheric Sciences Lanzhou UniversityLanzhou 730000China Collaborative Innovation Center for Western Ecological Safety Lanzhou UniversityLanzhou 730000China

As an important factor that directly affects agricultural production, the social economy, and policy implementation,observed changes in dry/wet conditions have become a matter of widespread concern. However, previous research has mainly focused on the long-term linear changes of dry/wet conditions, while the detection and evolution of the non-linear trends related to dry/wet changes have received less attention. The non-linear trends of the annual aridity index, obtained by the Ensemble Empirical Mode Decomposition(EEMD) method, reveal that changes in dry/wet conditions in China are asymmetric and can be characterized by contrasting features in both time and space in China. Spatially, most areas in western China have experienced transitions from drying to wetting, while opposite changes have occurred in most areas of eastern China. Temporally, the transitions occurred earlier in western China compared to eastern China. Research into the asymmetric spatial characteristics of dry/wet conditions compensates for the inadequacies of previous studies, which focused solely on temporal evolution;at the same time, it remedies the inadequacies of traditional research on linear trends over centennial timescales. Analyzing the non-linear trend also provides for a more comprehensive understanding of the drying/wetting changes in China.

关键词： aridity index EEMD dry/wet conditions asymmetric evolution

Asymptotic normality of error density estimator in stationary and explosive autoregressive models

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Applied Mathematics(A Journal of Chinese Universities) 2024年第1期39卷 140-158页

作者： wu Shi-peng YANG wen-zhi GAO Min hu Shu-he School of Mathematical Sciences&School of Big Data and Statistics Anhui UniversityHefei 230601China School of Statistics Shanxi University of Finance and EconomicsTaiyuan030006China

In this paper,we consider the limit distribution of the error density function estima-tor in the rst-order autoregressive models with negatively associated and positively associated random *** mild regularity assumptions,some asymptotic normality results of the residual density estimator are obtained when the autoregressive models are stationary process and explosive *** order to illustrate these results,some simulations such as con dence intervals and mean integrated square errors are provided in this *** shows that the residual density estimator can replace the density\estimator"which contains errors.

关键词： explosive autoregressive models residual density estimator asymptotic distribution association sequence

Evaluation of the binding affinity and antioxidant activity of phlorizin to pepsin and trypsin

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Food Science and human Wellness 2024年第1期13卷 392-400页

作者： Jing Zhang Lan Tang Xia hu Zhen Zeng wen wu Fang Geng hui Li Di wu Meat Processing Key Laboratory of Sichuan Province School of Food and Biological EngineeringChengdu UniversityChengdu 610106China School of Chemical Engineering Sichuan UniversityChengdu 610065China

Phlorizin(PHL)is a natural compound with strong antioxidant properties mainly found in *** this paper,the interaction mechanism of PHL with pepsin and trypsin was comparatively evaluated by computer simulation,fluorescence spectra,circular dichroism(CD),and Fourier transform infrared(FT-IR)spectra at a molecular *** spectra showed that PHL quenches the pepsin/trypsin by static *** parameters indicated that PHL binds to pepsin mainly through hydrogen bonds and van der Waals forces,and that of trypsin was electrostatic *** ground state complexes PHL and protease have a moderate affinity of 105 L/mol PHL binds more strongly to trypsin than to *** and FT-IR spectra results showed that pepsin/trypsin decreased theβ-sheet content and slightly changed its secondary structure upon *** experimental results are mutually verified with the predicted computer-aid simulation *** PHL and trypsin binding,the antioxidant capacity of PHL was ***,the antioxidant capacity of PHL was decreased after binding to *** work elucidates the binding of PHL binding mechanisms to pepsin/trypsin and provides useful information for the digestion of PHL to improve the application of PHL in food processing.

关键词： Interaction Phlorizin Pepsin Trypsin Antioxidation

Lightweight,Strong and High Heat-Resistant Poly(lactide acid)Foams via Microcellular Injection Molding with Self-Assembly Nucleating Agent

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Chinese Journal of Polymer Science 2024年第6期42卷 739-750页

作者： Xiao-hu Bing wen-Yu Ma Ming-hui wu Peng Gao Xiao Zhou Hai-Bin Luo Long Wang wen-Ge Zheng School of materials Science and Engineering Shanghai UniversityShanghai200444China Ningbo Key Lab of Polymer Materials Ningbo Institute of Material Technology and EngineeringChinese Academy of SciencesNingbo315201China University of Chinese Academy of Sciences Beijing100049China

Poly(lactide acid)(PLA)foams have shown considerable promise as eco-friendly alternatives to nondegradable plastic foams,such as polystyrene(PS)***,PLA foam typically suffers from low heat-resistance and poor cellular structure stemming from its inherent slow crystallization rate and low melt *** this study,a high-performance PLA foam with well-defined cell morphology,exceptional strength and enhanced heat-resistance was successfully fabricated via a core-back microcellular injection molding(MIM)*** scanning calorimetry(DSC)results revealed that the added hydrazine-based nucleating agent(HNA)significantly increased the crystallization temperature and accelerated the crystallization process of ***,the addition of a 1.5 wt%of HNA led to a significant reduction in PLA’s cell size,from 43.5µm to 2.87µm,and a remarkable increase in cell density,from 1.08×10^(7)cells/cm^(3)to 2.15×10^(10)cells/cm^(3).This enhancement resulted in a final crystallinity of approximately 55.7%for the PLA blend foam,a marked improvement compared to the pure PLA ***,at 1.5 wt%HNA concentration,the tensile strength and tensile toughness of PLA blend foams demonstrated remarkable improvements of 136%and 463%,***,the Vicat softening temperature of PLA blend foam increased significantly to 134.8°C,whereas the pure PLA foam exhibited only about 59.7℃.These findings underscore the potential for the preparation of lightweight injection-molded PLA foam with enhanced toughness and heat-resistance,which offers a viable approach for the production of high-performance PLA foams suitable for large-scale applications.

关键词： Poly(lactide acid) Nucleating agent Microcellular injection molding Heat-resistance Toughness

High-temperature stability of retained austenite and plastic deformation mechanism of ultra-fine bainitic steel isothermally treated below Ms

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Journal of Iron and Steel Research International 2024年第8期31卷 2014-2030页

作者： Ting-ting He Feng hu Kun Wang wen Zhou Li Li Serhii Yershov Kai-ming wu The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina Collaborative Innovation Center for Advanced Steels Wuhan University of Science and TechnologyWuhan 430081HubeiChina Zhejiang Tsingshan Iron and Steel Co. Ltd.Qingtian 323903ZhejiangChina

The mechanical properties of the sample and the stability of retained austenite were studied by designing two kinds of ultra-fine bainitic steel with different heat treatment methods austempering above and below Ms(martensite start tem-perature),which were subjected to tensile tests at 20 and 450℃,*** results show that compared to room temperature(20℃)tensile properties,the uniform elongation of the sample at high temperature(450℃)significantly ***,the uniform elongation of the sample austempered above Ms decreased from 8.0%to 3.5%,and the sample austempered below Ms decreased from 10.9%to 3.1%.Additionally,the tensile strength of the sample austempered above Ms significantly decreased(from 1281 to 912 MPa),and the sample austempered below Ms slightly decreased(from 1010 to 974 MPa).This was due to the high carbon content(1.60 wt.%),high mechanical stability,low thermal stability for the retained austenite of the sample austempered below ***,the retained austenite decomposed at high temper-atures,the carbon content and transformation driving force were significantly reduced,the transformation rate increased,and the phase transformation content reduced.

关键词： Ultra-fine bainite Isothermal treatment High-temperature tensile property Retained austenite stability Plastic deformation

BSIN: A Behavior Schema of Information Networks Based on Approximate Bisimulation

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Tsinghua Science and Technology 2024年第4期29卷 1092-1104页

作者： wujie hu Jinzhao wu School of Electrical Engineering Guangxi UniversityNanning 530004China

Information networks are becoming increasingly important in practice. However, their escalating complexity is gradually impeding the efficiency of data mining. A novel network schema called the Behavior Schema of Information Networks (BSIN) is proposed to address this issue. This work defines the behavior of nodes as connected paths in BSIN, proposes a novel function distinguish behavior differences, and introduces approximate bisimulation into the acquisition of quotient sets for node types. The major highlight of BSIN is its ability to directly obtain a high-efficiency network on the basis of approximate bisimulation, rather than reducing the existing information network. It provides an effective representation of information networks, and the resulting novel network has a simple structure that more efficiently expresses semantic information than current network representations. The theoretical analysis of the connected paths between the original and the obtained networks demonstrates that errors are controllable;and semantic information is approximately retained. Case studies show that BSIN yields a simple network and is highly cost-effective.

关键词： data mining information network approximate bisimulation controllable error

Optimization of jamming formation of USV offboard active decoy clusters based on an improved PSO algorithm

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Defence Technology（防务技术） 2024年第2期32卷 529-540页

作者： Zhaodong wu Yasong Luo Shengliang hu College of Weapons Engineering PLA Naval University of EngineeringWuhan430033China

Offboard active decoys(OADs)can effectively jam monopulse ***,for missiles approaching from a particular direction and distance,the OAD should be placed at a specific location,posing high requirements for timing and *** improve the response speed and jamming effect,a cluster of OADs based on an unmanned surface vehicle(USV)is *** formation of the cluster determines the effectiveness of ***,based on the mechanism of OAD jamming,critical conditions are identified,and a method for assessing the jamming effect is ***,for the optimization of the cluster formation,a mathematical model is built,and a multi-tribe adaptive particle swarm optimization algorithm based on mutation strategy and Metropolis criterion(3M-APSO)is ***,the formation optimization problem is solved and analyzed using the 3M-APSO algorithm under specific *** results show that the improved algorithm has a faster convergence rate and superior performance as compared to the standard Adaptive-PSO *** with a single OAD,the optimal formation of USV-OAD cluster effectively fills the blind area and maximizes the use of jamming resources.

关键词： Electronic countermeasure Offboard active decoy USV cluster Jamming formation optimization Improved PSO algorithm

Effect of cardiac rehabilitation care after coronary intervention on cardiac function recovery and negative mood in patients with myocardial infarction

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World Journal of Clinical Cases 2024年第1期12卷 59-67页

作者： Ming Yang Yuan-Tao huang Xi-wen hu Chun-Ling wu Division of Cardiovascular First Ward Departments of Internal MedicineLiyuan HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430077Hubei ProvinceChina Division of Cardiovascular First Ward Departments of Internal MedicineJianli People's HospitalJianli 433300Hubei ProvinceChina Department of Integrated Traditional Chinese and Western Medicine People's Hospital of Dongxihu DistrictWuhan 430040Hubei ProvinceChina

BACKGROUND Cardiovascular disease,particularly myocardial infarction(MI)profound impact on patients'quality of life and places a substantial burden on the healthcare and economy *** in medical technology have led to the emer-gence of coronary intervention as an essential method for treating *** To assess the effects of cardiac rehabilitation care on cardiac function recovery and negative emotions in MI after coronary *** This study included a total of 180 patients with MI during the period from June 2022 to July *** patients were divided into two groups:An observation group,which receiving cardiac rehabilitation care;a control group,which re-ceiving conventional *** comparing multiple observation indicators such as cardiac function indicators,blood pressure,exercise tolerance,occurrence of adverse cardiac events,and negative emotion scores between the two groups of *** the data were analyzed and compared between two *** There were 44 males and 46 females in the observation group with an average age of 36.26±9.88 yr;there were 43 males and 47 females in the control group,with an average age of 40.87±10.5 *** receiving the appropriate postoperative nursing measures,the results of the observation group showed significant improvement in several indicators compared with the control *** of cardiac function,such as left ventricular end-diastolic internal diameter and left ventricular ejection fraction were significantly better in the observation group than in the control group(P<0.05).Exercise endurance assessment showed that the 6-minute walking test distance was significantly increased in the patients of the observation group(P<0.01).In addition,the incidence of adverse cardiac events was significantly lower in the observation group,and negative mood scores were significantly reduced(P<0.05).CONCLUSION Cardiac rehabilitation care after coronary intervention has a significant positive

关键词： Myocardial infarction Coronary artery intervention Cardiac rehabilitation Cardiac function recovery Negative emotions