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A Bionic Study on the Anti-erosion Mechanism of Laudakia stoliczkana:Experimental and Numerical Aspects

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Journal of Bionic Engineering 2019年第5期16卷 882-893页

作者： ping Liang Youhong Sun Sihan Liu Tianwei Liang Yuhang Zhang Youwei Wang Luquan Ren Key Laboratory of Bionic Engineering Ministry of EducationJilin UniversityChangchun 130022China Construction Engineering College Jilin UniversityChangchun 130000China School of Mechanical and Aerospace Engineering Jilin UniversityChangchun 130022China China FAW Group Corporation R&D Center Changchun 130000China

The scales of body surface of Laudakia stoliczkana have the morphology of convex hulls,which are arranged in groove structure in macroscopic *** body surface skin is mainly composed of the"soft"layer of keratin and the"hard"layer of the cuticle covering on the"soft"*** coupling effect of the scale morphology and skin's structure gives Laudakia stoliczkana the excellent ability to resist the sand erosion in desert *** by the convex surface morphology and the composite structure of the"soft"and"hard"layers of the skin of Laudakia stoliczkana^the coupling bionic samples are febricated and the erosion resistance performance is *** test results show that the coupling bionic samples have good erosion resistance perfbimance and the samples with spherical convex hull exhibit the best erosion resistance ***,based on the theory of stress wave propagation in solid the numerical simula tions of particles impacting to the coupling bionic samples and bionic layered structure are done respectively and the anti-erosion me chanism of the bionic layered structure is *** simulation results are consistent with the experimental results,which show that the coupling bionic samples can effectively reduce the amplitude of the incident stress wave,and thus can prevent the failure of samples.

关键词： coupling bionic anti-erosion sand blasting test stress wave bionic layered structure

Microstructures and properties of Cu-Cr-W composite coatings fabricated by surface mechanical alloying technique

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Rare Metals 2022年第12期41卷 4248-4256页

作者： Jia-ping Zhang Xiao-Mei Feng Yi-Fu Shen Cheng Chen Cui-Yuan Duan College of Materials Science and Technology Nanjing University of Aeronautics and AstronauticsNanjing 210016China

Cu-Cr-W composite coatings were prepared by mechanical alloying(MA)method using different powder ratios,rotational speeds and milling *** micro structures and chemical compositions of as-synthesized coatings were analyzed by scanning electron microscopy(SEM)and energy-dispersive spectroscopy(EDS).Phases of ball-milled powders were identified by X-ray diffraction(XRD).The results indicate that the coating fabricated with powder ratio of 40 wt%Cu-Cr-W has better surface and cross-sectional microstructures and higher *** comparisons of cross-sectional micro structures of the coatings fabricated at different rotational speeds suggest that rotational speed of 300 r·min-1is the optimal for fabrication the coating,and the optimal milling time for the formation of coating is 7 *** results of microhardness test show that the hardness of the substrate is largely improved because of the as-fabricated *** results of the friction and wear tests indicate that the wear resistance of the copper substrate is improved after the deposition of Cu-Cr-W coating on *** coating fabricated for 7 h exhibits the lowest friction coefficient,indicating its favorable friction and wear *** formation mechanism of the coating was *** to the investigations in this work,the Cu-Cr-W coating fabricated by MA method is considered to be effective to reinforce the copper substrate.

关键词： Mechanical alloying Composite coating Powder ratio Processing parameter

Factor analysis on the purity of magnesium titanate directly prepared from seashore titanomagnetite concentrate through direct reduction

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International Journal of Minerals,Metallurgy and Materials 2020年第11期27卷 1462-1470页

作者： Xiao-ping Wang Zhao-chun Li Ti-chang Sun Jue Kou Xiao-hui Li School of Mining and Coal Inner Mongolia University of Science and TechnologyBaotou 014010China China Sinda Intellectual Property Limited Beijing 100033China School of Civil and Resource Engineering University of Science and Technology BeijingBeijing 100083China

Magnesium titanate was prepared directly through external coal reduction of seashore titanomagnetite concentrate and magnesium oxide(MgO).The effects of roasting temperature and the type and dosage of reductants on the purity of generated magnesium titanate particles were systematically *** electron microscopy and energy-dispersive spectroscopy analyses were performed to characterize the magnesium titanate particles and observe their purity under different *** showed that the roasting temperature remarkably influenced the purity of magnesium *** 1200,1300,and 1400℃,some magnesium ferrite and magnesium aluminate spinel were dissolved in magnesium ***,as the roasting temperature increased to 1500℃,relatively pure magnesium titanate particles were generated because no magnesium ferrite was dissolved in *** type and dosage of the reductants also remarkably affected the purity of magnesium *** amount of fine metallic iron disseminated in the magnesium titanate particles obviously decreased when lignite was used as a reductant at a dosage of 70wt%.Thus,high-purity magnesium titanate particles *** a roasting temperature of 1500℃and with 70wt%lignite,the magnesium titanate product with a yield of 30.63%and an iron content of 3.01wt%was obtained through magnetic separation.

关键词： seashore titanomagnetite magnesium oxide direct reduction magnesium titanate

Preparation of Alum-borneol-PVP Drug-loaded Fibers by Electrospinning

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Chemical Research in Chinese Universities 2021年第3期37卷 411-418页

作者： HUANG Libing LIU Yueqi SANG Xinyu SONG Jinghui HU ping LIU Yong College of Mechanical and Electric Engineering Beijing University of Chemical TechnologyBeijing100029P.R.China Beijing Key Laboratory of Advanced Functional Polymer Composites College of Materials Science and EngineeringBeijing University of Chemical TechnologyBeijing100029P.R.China

The alum-borneol nanoemulsion(ABN),which combines the mineral medicine alum and the botanical medicine borneol,has been applied for approximately 40 years in the clinical treatment of burns,scalds,radiation dermatitis and shingles,and has a good curative ***,the current formula and dosage form of ABN pose problems of low borneol content and ease of precipitation,which greatly affects the efficacy of the *** this study,polyvinylpyrrolidone(PVP)was selected as a carrier mixed with different proportions of alum and borneol to produce alum-borneol-PVP fibers(ABPF)by *** results showed that the stable system with good drug dispersion was 2:3(alum:borneol).The dissolution content of borneol from the ABPF was about 80%in 4 h,which was much higher than that of the alum-borneol liquid(ABL)and *** ABPF membrane showed a more significant inhibitory effect on Staphylococcus aureus than the ABL and *** composite fiber markedly increased the drug content of borneol,which was 800 times of that in *** fiber had a higher solubility than the nanoemulsion in vitro,which is of great importance for the development of new forms for the clinical application of alum and borneol.

关键词： Drug delivery Dissolution content Bioavailability Antibacterial Fiber membrane

Perinatal prevalence of birth defects in the Mainland of China,2000–2021:a systematic review and meta-analysis

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World Journal of Pediatrics 2024年第7期20卷 669-681页

作者： Liang-Yu Kang Zi-Rui Guo Wei-Jing Shang Gui-Ying Cao Yi-ping Zhang Qiao-Mei Wang Hai-ping Shen Wan-Nian Liang Min Liu Department of Epidemiology and Biostatistics School of Public HealthPeking UniversityNo.38Xueyuan RoadHaidian DistrictBeijing100191China Vanke School of Public Health Tsinghua UniversityNo.1Tsinghua GardenHaidian DistrictBeijing100084China Department of Maternal and Child Health National Health Commission of the People’s Republic of ChinaNo.1Xizhimenwai South RoadXicheng DistrictBeijingChina Institute of Healthy China Tsinghua UniversityNo.1Tsinghua GardenHaidian DistrictBeijing100084China Key Laboratory of Epidemiology of Major Diseases(Peking University) Ministry of Education BeijingNo.38Xueyuan RoadHaidian DistrictBeijing100191China

Background Although birth defects are of great concern globally,the latest national prevalence has not yet been quantified in *** conducted a systematic review and meta-analysis to estimate the perinatal prevalence of birth defects in the Mainland of China between 2000 and *** We performed a systematic literature search of six databases for relevant articles published between January 1,2000,and March 1,*** included published studies that reported data on the perinatal prevalence of birth defects in the Mainland of *** DerSimonian and Laird random-effects models were used to estimate the pooled prevalence and its 95%confidence interval(CI).We also conducted subgroup analyses and univariable meta-regressions to explore differences in prevalence by time period,geographic region,and other *** We included 254 studies reporting the perinatal prevalence of birth defects and 86 studies reporting only the prevalence of specific types of birth *** on 254 studies covering 74,307,037 perinatal births and 985,115 cases with birth defects,the pooled perinatal prevalence of birth defects was 122.54(95%CI 116.20–128.89)per 10,000 perinatal births in the Mainland of China during 2000–***,the perinatal prevalence of birth defects increased from 95.60(86.51–104.69)per 10,000 in 2000–2004 to 208.94(175.67–242.22)per 10,000 in 2020–*** were also significant disparities among different geographical *** heart defects(33.35 per 10,000),clefts of the lip and/or palate(13.52 per 10,000),polydactyly(12.82 per 10,000),neural tube defects(12.82 per 10,000),and inborn errors of metabolism(11.41 per 10,000)were the five most common types of birth *** perinatal prevalence among males was significantly higher than that among females(β=2.44×10^(−3),P=0.003);a higher perinatal prevalence of birth defects was observed among perinatal births whose mothers were≥35 years(β=4.34×10^(−3),P<0.001).Conclusion Compreh

关键词： Birth defects China Perinatal Prevalence

Study on the Set-up and Set-down Induced by Breaking Waves Over A Reef

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China Ocean Engineering 2020年第6期34卷 853-862页

作者： LIU Qing-jun WANG Deng-ting WEI Zhang-ping XU Hua SUN Tian-ting Nanjing Hydraulic Research Institute Nanjing 210029China College of Harbour Coastal and Offshore Engineering Hohai UniversityNanjing 210098China Key Laboratory of Port Waterway&Sedimentation Engineering of MOTNanjing 210029China Department of Physics and Physical Oceanography University of North Carolina WilmingtonWilmingtonNC 28403USA

This paper proposes an equation to calculate breaking wave induced wave set-up and set-down along reef flat. The mathematical equation was derived based on the theory of radiation stress and the conservation of wave energy. The equation is primarily determined by several physical variables including the breaking wave index, the stable wave index, the attenuation coefficient of wave energy flux, and the flow velocity in the re-stabilization zone. A series of laboratory experiments were carried out to calibrate the theoretical equations. Specifically, the breaking wave index,the stable wave index, and the velocity over the reef flat were measured in the laboratory. The attenuation coefficient of wave energy flux in our theoretical equation was determined by calibration by comparing with the laboratory measured wave height. Furthermore, it has been put forward that the velocity based on cnoidal wave theory could be used to determine the velocity over the reef flat if there is no velocity measurement available. Overall, the proposed equation can provide satisfactory prediction of wave set-up and set-down along the reef flat.

关键词： wave set-up and set-down streamwise variation breaking waves reef flat reef terrain

Molecular Dynamics Simulations of Stretch-Induced Crystal Changes in Crystallized Polyethylene/Carbon Nanotubes Nanocomposites

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Chinese Journal of Polymer Science 2023年第9期41卷 1425-1438,I0007页

作者： Yu-Hang Zhou Jun Yang Zhi-ping Zhou Tong-Fan Hao Yi-Jing Nie Research School of Polymeric Materials School of Materials Science and EngineeringJiangsu UniversityZhenjiang212013China

Understanding deformation mechanisms in semi-crystalline polymers during stretching is useful for guiding the processing of highperformance polymer products. In the current work, molecular dynamics simulations were performed to investigate the crystal changes in crystallized polyethylene/carbon nanotube nanocomposites during uniaxial stretching. Both crystal fragmentation and melting occur at low strains. Crystals with small sizes are easier to melt, while those with large sizes would break into smaller crystals. In addition, crystals in interfacial regions are more likely to melt or break due to the orientation motion of carbon nanotubes. It was also found that the recrystallization process is closely related to the stretch-induced orientation of chain segments. After orientation of chain segments along stretching direction is saturated,the recrystallization of highly oriented segments dominates. The current simulation findings are effective complements to the theories of the mechanism of plastic deformation in semicrystalline polymers.

关键词： Molecular dynamics simulation Carbon nanotubes Stretching Melting and recrystallization

Bioinspired Additive Manufacturing of Hierarchical Materials: From Biostructures to Functions

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Research 2024年第1期2023卷 533-559页

作者： Jingjiang Wei Fei Pan Hang ping Kun Yang Yanqing Wang Qingyuan Wang Zhengyi Fu Institute for Advanced Materials Deformation and Damage from Multi-Scale Institute for Advanced StudyChengdu UniversityChengdu 610106P.R.China Department of Chemistry University of BaselBasel 4058Switzerland State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070P.R.China College of Polymer Science and Engineering Sichuan UniversityChengdu 610065P.R.China

Throughout billions of years,biological systems have evolved sophisticated,multiscale hierarchical structures to adapt to changing *** are synthesized under mild conditions through a bottom-up self-assembly process,utilizing substances from the surrounding environment,and meanwhile are regulated by genes and *** manufacturing,which mimics this natural process,provides a promising approach to developing new materials with advantageous properties similar to natural biological *** review presents an overview of natural biomaterials,emphasizing their chemical and structural compositions at various scales,from the nanoscale to the macroscale,and the key mechanisms underlying their ***,this review describes the designs,preparations,and applications of bioinspired multifunctional materials produced through additive manufacturing at different scales,including nano,micro,micro-macro,and macro levels.

关键词： materials structures utilizing

Plant cell totipotency: Insights into cellular reprogramming

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Journal of Integrative Plant Biology 2021年第1期63卷 228-240页

作者： Ying Hua Su Li ping Tang Xiang Yu Zhao Xian Sheng Zhang State Key Laboratory of Crop Biology College of Life SciencesShandong Agricultural UniversityTai'an 271018China

Plant cells have a powerful capacity in their propagation to adapt to environmental change, given that a single plant cell can give rise to a whole plant via somatic embryogenesis without the need for fertilization. The reprogramming of somatic cells into totipotent cells is a critical step in somatic embryogenesis. This process can be induced by stimuli such as plant hormones, transcriptional regulators and stress. Here, we review current knowledge on how the identity of totipotent cells is determined and the stimuli required for reprogramming of somatic cells into totipotent cells. We highlight key molecular regulators and associated networks that control cell fate transition from somatic to totipotent cells. Finally,we pose several outstanding questions that should be addressed to enhance our understanding of the mechanisms underlying plant cell totipotency.

关键词： cell reprogramming plant cell totipotency somatic embryogenesis totipotent cell