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Effect of Chain Extender on Hydrogen Bond and Microphase Structure of Biodegradable Thermoplastic Polyurethanes

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Chinese Journal of Polymer Science 2018年第4期36卷 514-520页

作者： Wen-Kai liu Yun Zhao Rong Wang feng Luo Jian-Shu li Jie-Hua li Hong Tan College of Polymer Science and Engineering State Key Laboratory of Polymer Materials Engineering Sichuan University

Thermomechanical properties of polyurethanes（PUs） strongly depend on the molecular interactions and microphase structure. In this work, two chain extenders with different ratios, flexile 1,4-butanediol（BDO） and branched trimethylolpropane mono allyl ether（TMPAE）, are used to tune the molecular interactions and microphase structures of a series of biodegradable thermoplastic polyurethanes（TPUs）. In TPUs, the biodegradable polycaprolactone（PCL, M_n of 2000） is used as soft segment while 1,6-diisocyanatohexane（HDI） and chain extenders are used as hard segment. Fourier transform infrared spectroscopy（FTIR）, proton nuclear magnetic resonance spectroscppy（~1 H-NMR）, gel permeation chromatography（GPC）, differential scanning calorimetry（DSC）, dynamic mechanical analysis（DMA） and mechanical tests were performed to characterize the bulk structure and properties of TPUs. Compared with BDO, the steric bulk of TMPAE is larger. The increment of TMPAE can help to increase the hydrogen bond content, microphase separation, and the elastic modulus ratio（R）, which would strongly affect the thermomechanical property of the TPUs. The results of this work verify the importance of the structure of chain extender on the properties of TPUs. It provides valuable information for further understanding the structure-property relationships of these polyurethanes.

关键词： Chain extender Hydrogen bond Crystallinity Polyurethane

Identification of two clip domain serine proteases involved in the pea aphid's defense against bacterial and fungal infection

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Insect Science 2020年第4期27卷 735-744页

作者： li Ma feng Chen Wen Wang Lu Xu Zhi-Qiang Lu Department of Entomology College of Plant ProtectionNorthwest A&F UniversityYanglingShaanxiChina Key Laboratory of Plant Protection Resources and Pest Management Ministry of EducationNorthwest A&F UniversityYanglingShaanxiChina

Phenoloxidases(POs)are required for the pea aphid s defense against bacterial and fungal ***(PPOs)are protcolytically converted to its active form PO through a clip domain serine protease *** this study,we identified five clip domain serine proteases in the pea *** messenger RNA levels of two of them,*** and Ap_VP,were upregulated by Gram-positive bacterium Staphylococcus aureus and fungus Beauveha bassiana ***-stranded RNA-based expression knockdown of these two genes resulted in reduced PO activity of the aphid hemolymph,higher loads of *** and *** in the aphids,and lower survival rates of the aphids after *** data suggest that *** and Ap_VP are involved in PPO activation pathway in the pea aphid.

关键词： defense pea aphid prophenoloxidase RNA interference serine proteases

Preliminary prediction of the control reproduction number of COVID-19 in Shaanxi Province,China

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Applied Mathematics(A Journal of Chinese Universities) 2021年第2期36卷 287-303页

作者： li Zhi-min ZHANG Tai-lei GAO Jian-zhong li Xiu-qing MA ling juan BAO Xiong-xiong School of Science Chang'an UniversityXi'an 710064China School of Ecological Environment Northwestern Polytechnical UniversityXi'an 710072China College of Economics and Management Shanxi Normal UniversityLinfen 041004China

Objectives Firstly,according to the characteristics of COVID-19 epidemic and the control measures of the government of Shaanxi Province,a general population epidemic model is ***,the control reproduction number of general population epidemic model is *** on the epidemic model of general population,the epidemic model of general population and college population is further established,and the control reproduction number is also *** For the established epidemic model,firstly,the expression of the control reproduc-tion number is obtained by using the next generation ***,the real-time reported data of COVID-19 in Shaanxi Province is used to fit the epidemic model,and the parameters in the model are estimated by least square method and ***,the Latin hypercube sampling method and partial rank correlation coefficient(PRCC)are adopted to analyze the sensitivity of the *** The control reproduction number remained at 3 from January 23 to January 31,then gradually decreased from 3 to slightly greater than 0.2 by using the real-time reports on the number of COVID-19 infected cases from Health Committee of Shaanxi Province in *** order to further control the spread of the epidemic,the following measures can be taken:(i)reducing infection by wearing masks,paying attention to personal hygiene and limiting travel;(i)improving isolation of suspected patients and treatment of symptomatic *** particular,the epidemic model of the collge population and the general population is estab-lished,and the control reproduction number is given,which will provide theoretical basis for the prevention and control of the epidemic in the colleges.

关键词： COVID-19 control reproduction number general population college population Shaanxi Province

Metallurgy and Solidification Microstructure Control of Fusion-Based Additive Manufacturing Fabricated Metallic Alloys:A Review

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Acta Metallurgica Sinica(English Letters) 2024年第1期37卷 29-53页

作者： Qiang li Xing-Ran li Bai-Xin Dong Xiao-Long Zhang Shi-li Shu feng Qiu Lai-Chang Zhang Zhi-Hui Zhang Key Laboratory of Bionic Engineering(Ministry of Education) and College of Bionic Science and EngineeringJilin UniversityChangchun130022China Institute of Structured and Architected Materials Liaoning Academy of MaterialsShenyang110167China Key Laboratory of Automobile Materials Ministry of Education and Department of Materials Science and EngineeringJilin UniversityChangchun130025China School of Mechanical and Aerospace Engineering Jilin UniversityChangchun130025China School of Engineering Edith Cowan University270 Joondalup DriveJoondalupPerthWA6027Australia

The metal-based additive manufacturing(AM),also referred to as metal 3D printing,has drawn particular interest because it enables direct creation,aided by computationally-directed path design,of intricate components with site-specific compositions and geometrical requirements as well as low buy-to-fly *** the last two decades,the objective of this revolutionary technology has been shifting from only“rapid prototyping”to advanced manufacturing of special high-end products or devices,which,in many aspects,outperform conventional manufacturing *** fusion-based AM,significant progress has been achieved in understanding the processing window of macroscopic scales,non-equilibrium metallurgy of mesoscale scales,and grain evolution of microscopic *** the versatile capacity of AM facilitates new avenues for discovering advanced materials and structures,their potential has still not been fully *** the unique non-equilibrium solidification during the AM process,coarse columnar grains with strong textures are usually developed along the build direction,which downgrades the mechanical *** push the limits of this digital manufacturing,this review attempts to provide in-depth and comprehensive overviews of the recent progress in understanding the evolution and control of the as-built microstructure that has been made recently and the challenges encountered during the AM process.

关键词： Additive manufacturing Temperature field Microstructure control Nanoparticles Functionally graded materials

Simulation of rice grain breakage process based on Tavares UFRJ model

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Particuology 2024年第10期93卷 65-74页

作者： Shaohang Shen Shouyu Ji Dan Zhao Yanlong Han Hao li Ze Sun Zhuozhuang li Anqi li Wenyu feng Jiaming Fei Fuguo Jia Yang li College of Engineering Northeast Agricultural UniversityHarbin150030China School of Water Conservancy and Civil Engineering Northeast Agricultural UniversityHarbin150030China College of Food Science Northeast Agricultural UniversityHarbin150030China

Understanding the breakage characteristics of rice grains is an important means to reduce rice breakage rate. However, the dynamic breakage mechanism of rice grain is unclear due to the lack of a reasonable breakage model. In this study, the uniaxial compression test and drop weight test of single rice were carried out, the breakage model of rice grain was constructed, the reliability of rice model was verified by the experiment and simulation results. The results showed that the fracture energy distribution of rice can be obtained by uniaxial compression test, the specific fracture energy of rice accords with a lognormal distribution, and the median specific fracture energy of rice is 479.75 J/kg. The damage accumulation coefficient and fragment size distribution of rice can be acquired by drop test, the result of damage accumulation coefficient of rice was 4.3. Rice grain breakage mainly occurs in the milling section of the vertical circulation rice mill.

关键词： Rice breakage mechanism Discrete element method Parameter calibration

New Carbon Nitride C_(3)N_(3) Additive for Improving Cationic Defects of Perovskite Solar Cells

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Energy & Environmental Materials 2023年第1期6卷 281-288页

作者： Zuhong li Jiaxin feng Jinguo Cao Jiaren Jin Yijun Zhou Duoling Cao Zihui liang Bicheng Zhu Ming li li Zhao Shimin Wang Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials Ministry of Education Key Laboratory for the Green Preparation and Application of Functional MaterialsSchool of Materials Science and EngineeringHubei UniversityWuhan 430062China Collaborative Innovation Center for Advanced Organic Chemical Materials Co-constructed by the Province and Ministry Ministry-of-Education Key Laboratory for the Synthesis and Application of Organic Functional MoleculesHubei Key Laboratory of Polymer MaterialsSchool of Chemistry and Chemical EngineeringHubei UniversityWuhan 430062China Laboratory of Solar Fuel Faculty of Materials Science and ChemistryChina University of GeosciencesWuhan 430074China

Due to the loss of organic amine cations and lead ions in the structure of the iodine-lead methylamine perovskite solar cell,there are a large number of defects within the film and the recombination loss caused by grain boundaries,which seriously hinder the further improvement of power conversion efficiency and ***,a novel carbon nitride C_(3)N_(3) incorporated into the perovskite precursor solution is a multifunctional strategy,which not only increases the light absorption strength,grain size,and hydrophobicity of the perovskite film,but also effectively passivates the bulk and interfacial defects of perovskite and verified by the first-principles density functional theory *** a result,the efficiency and stability of perovskite solar cells are *** device with 0.075 mg mL^(-1) C_(3)N_(3) additive delivers a champion power conversion efficiency of 19.91%with suppressed hysteresis,which is significantly higher than the 18.16% of the control *** addition,the open-circuit voltage of the modified device with the maximum addition as high as 1.137 V is 90.96% of the Shockley–Queisser limit(1.25 V).Moreover,the power conversion efficiency of the modified device without encapsulation can maintain nearly 90% of its initial value after being stored at 25℃ and 60% relative humidity for 500 *** work provides a new idea for developing additives to improve the power conversion efficiency and stability of perovskite solar cells.

关键词： additive C_(3)N_(3) humidity stability passivate defect perovskite solar cells

A case report of multimodal ultrasound imaging in the diagnosis of giant retroperitoneal ganglioneuroma

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Cancer Innovation 2023年第5期2卷 433-437页

作者： li feng Yong Wang Department of Ultrasound National Cancer CenterNational Clinical Research Center for CancerCancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina

Retroperitoneal ganglioneuroma is a rare benign tumor that is challenging in terms of clinical *** tomography and magnetic resonance imaging are usually performed for diagnosis rather than convenient and inexpensive ***,we present the case of a 21‐year‐old female patient who was diagnosed by multimodal ultrasound imaging and whose diagnosis was confirmed by ultrasound‐guided core needle biopsy before *** hope that this rare case will help clinicians and radiologists realize the advantages of multimodal ultrasound imaging in the diagnosis of retropeitoneal solid tumors,and reduce misdiagnosis.

关键词： diagnosis ganglioneuroma retroperitoneal mass ultrasonography

Application and Effectiveness of Chinese Medicine in Regulating Immune Checkpoint Pathways

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Chinese Journal of Integrative Medicine 2023年第11期29卷 1045-1056页

作者： XIONG Luo-jie TIAN Yue-feng ZHAI Chun-tao li Wei College of Acupuncture Massage and RehabilitationHunan University of Chinese MedicineChangsha(410208)China Second Clinical College Shanxi University of Chinese MedicineJinzhongShanxi Province(030619)China

Immunotherapy targeting immune checkpoint molecules has emerged as a key approach in cancer treatment,representing the forefront of antitumor ***,studies on immune checkpoint molecules have mainly focused on targeted *** medicine(CM)research as a complementary medicine has revealed that immune checkpoint molecules also undergo disease-specific changes in the context of autoimmune *** review article presents a comprehensive analysis of CM studies on immune checkpoint molecules in the last 5 years,with a focus on their role in different diseases and treatment *** research predominantly utilizes oral administration of herbal plant extracts or acupuncture techniques,which stimulate the immune system by activating specific acupoints through temperature and *** this study,we analyzed the modulation and mechanisms of immune checkpoint molecules associated with different coinhibitory and costimulatory molecules,and reviewed the immune functions of related molecules and CM studies in treating autoimmune diseases and *** summarizing the characteristics and research value of CM in regulating immune checkpoint molecules,this review aims to provide a useful reference for future studies in this field.

关键词： acupuncture herbal Immune

Supermassive black holes triggered by QCD axion bubbles

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Communications in Theoretical Physics 2024年第5期76卷 134-139页

作者： Hai-Jun li Ying-Quan Peng Wei Chao Yu-feng Zhou Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China Center for Advanced Quantum Studies Department of PhysicsBeijing Normal UniversityBeijing 100875China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUCASHangzhou 310024China International Centre for Theoretical Physics Asia-Pacific Beijing/HangzhouChina

Supermassive black holes(SMBHs)are ubiquitous in the center of galaxies,although the origin of their massive seeds is still *** this paper,we investigate the formation of SMBHs from the quantum chromodynamics(QCD)axion *** this case,primordial black holes(PBHs)are considered as the seeds of SMBHs,which are generated from the QCD axion bubbles due to an explicit Peccei–Quinn(PQ)symmetry breaking after *** QCD axion bubbles are formed when the QCD axion starts to oscillate during the QCD phase *** consider a general case in which the axion bubbles are formed with the bubble effective angle θ_(eff)∈(0,π],leading to the minimum PBH mass∼■(10^(4)−10^(7))M⊙for the axion decay constant f_(a)∼■(10^(16))*** PBHs at this mass region may account for the seeds of SMBHs.

关键词： supermassive black holes primordial black holes quantum chromodynamics axion