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Nontoxic chemical crosslinked bacterial cellulose-heparin-gelatin composite hydrogel as antibacterial dressing

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Journal of Materials Science & Technology 2024年第11期178卷 29-38页

作者： Ruixuan liu Jingting Cai Nana qin Kexin Zhang Tongyang Li Hao Luo Dadang guo State Key Laboratory for Mechanical Behavior of Materials School of Materials Science and EngineeringXi'an Jiaotong UniversityXi'an 710049China Northwest Institute for Non-ferrous Metal Research Xi'an 710016China College of fashion and art design Xi'an Polytechnic UniversityXi'an 710048China Frontier Institute of Science and Technology Xi'an Jiaotong UniversityXi'an 710049China.

A hydrogel dressing based on bacterial cellulose(BC),which is grafted with quaternary ammonium func-tional and crosslinked with the gelatin-heparin system,is prepared to provide the features mainly con-cerning softness,high swelling ratio,antibacterial property,and *** innovation of prepa-ration is that the BC is beaten into short-chain scaffolds to improve the efficiency of grafting,which not only simplifies the preparation process but also avoids the biotoxicity caused by the introduction of toxic catalyst such as dimethyl sulfoxide(DMSO)or uncertain toxic side products in long-chain *** electron microscopy(SEM)shows that the QBC/Hep/Gel composite hydrogel possesses a three-dimensional mesh structure with high *** hydrogel shows outstanding water manage-ment performance indicated by the swelling ratio of 1476%,water retention ratio of more than 90%at 120 h,and moisture permeability of 3296 g m^(-2) 24 h^(-1).The antibacterial experiment is implemented with staphylococcus aureus,and the antibacterial effect is represented by an inhibition zone of 3 cm in *** vivo animal experiments suggested that QBC/Hep/Gel could effectively promote epithelial reconstruction,collagen deposition,and angiogenesis in normal wounds,reduce inflammation,and ac-celerate wound *** these results indicate that the proposed QBC/Hep/Gel hydrogel is a potential composite for antibacterial dressing.

关键词： Antibacterial dressings Hydrogel dressings Wound healing Cross-linking

The role of polyurethane foam compressible layer in the mechanical behaviour of multi-layer yielding supports for deep soft rock tunnels

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第11期16卷 4554-4569页

作者： Haibo Wang Fuming Wang Chengchao guo Lei qin Jun liu Tongming Qu School of Civil Engineering Sun Yat-sen UniversityGuangzhou510275China Southern Marine Science and Engineering Guangdong Laboratory Zhuhai519000China Guangdong Key Laboratory of Oceanic Civil Engineering Zhuhai519082China Guangdong Research Center for Underground Space Exploitation Technology Guangzhou510275China Southern Institute of Infrastructure Testing and Rehabilitation Technology Huizhou516029China Department of Hydraulic Engineering School of Infrastructure EngineeringDalian University of TechnologyDalian116024China Department of Civil and Environmental Engineering Hong Kong University of Science and TechnologyClearwater BayKowloonHong KongChina

The polyurethane foam(PU)compressible layer is a viable solution to the problem of damage to the secondary lining in squeezing ***,the mechanical behaviour of the multi-layer yielding supports has not been thoroughly *** fill this gap,large-scale model tests were conducted in this *** synergistic load-bearing mechanics were analyzed using the convergenceconfinement *** types of multi-layer yielding supports with different thicknesses(2.5 cm,3.75 cm and 5 cm)of PU compressible layers were investigated *** image correlation(DIC)analysis and acoustic emission(AE)techniques were used for detecting the deformation fields and damage evolution of the multi-layer yielding supports in *** indicated that the loaddisplacement relationship of the multi-layer yielding supports could be divided into the crack initiation,crack propagation,strain-hardening,and failure *** with those of the stiff support,the toughness,deformability and ultimate load of the yielding supports were increased by an average of 225%,61%and 32%,***,the PU compressible layer is positioned between two primary linings to allow the yielding support to have greater mechanical *** analysis of the synergistic bearing effect suggested that the thickness of PU compressible layer and its location significantly affect the mechanical properties of the yielding *** use of yielding supports with a compressible layer positioned between the primary and secondary linings is recommended to mitigate the effects of high geo-stress in squeezing tunnels.

关键词： Multi-layer yielding supports Polyurethane foam compressible layer Synergistic mechanism Large-scale model test Deep soft rock tunnels

Natural frequency analysis of laminated piezoelectric beams with arbitrary polarization directions

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Applied Mathematics and Mechanics(English Edition) 2024年第11期45卷 1949-1964页

作者： Zhi LI Cuiying FAN Mingkai guo guoshuai qin Chunsheng LU Dongying liu Minghao ZHAO School of Mechanics and Safety Engineering Zhengzhou UniversityZhengzhou450001China School of Electromechanical Engineering Henan University of TechnologyZhengzhou450001China School of Civil and Mechanical Engineering Curtin UniversityPerthWestern Australia6845Australia School of Civil Engineering Guangzhou UniversityGuangzhou510006China Henan Province Industrial Science&Technology Institute for Anti-fatigue Manufacturing Zhengzhou450001China Henan Province Engineering Research Center of Anti-fatigue Manufacturing Technology Zhengzhou450001China

Piezoelectric devices exhibit unique properties that vary with different vibration modes,closely influenced by their polarization *** paper presents an analysis on the free vibration of laminated piezoelectric beams with varying polarization directions,using a state-space-based differential quadrature ***,based on the electro-elasticity theory,the state-space method is extended to anisotropic piezoelectric materials,establishing state-space equations for arbitrary polarized piezoelectric beams.A semi-analytical solution for the natural frequency is then obtained via the differential quadrature *** study commences by examining the impact of a uniform polarization direction,and then proceeds to analyze six polarization schemes relevant to the current research and ***,the effects of geometric dimensions and gradient index on the natural frequencies are *** numerical results demonstrate that varying the polarization direction can significantly influence the natural frequencies,offering distinct advantages for piezoelectric elements with different *** research provides both theoretical insights and numerical methods for the structural design of piezoelectric devices.

关键词： piezoelectric laminated beam free vibration arbitrary polarization state-space equation differential quadrature method natural frequency

Two-sided Long Baseline Radargrammetry from Ascending Descending Orbits with Application to Mapping Post-seismic Topography in the West Sichuan Foreland Basin

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Journal of Mountain Science 2014年第5期11卷 1298-1307页

作者： CHENG Hai-qin CHEN Qiang liu guo-xiang YANG Ying-hui liu Li-yao Department of Remote Sensing and Geoinformation Engineering Southwest Jiaotong University School of Civil Engineering and Architecture East China Jiaotong University

One-sided ascending or descending Synthetic Aperture Radar（SAR） stereoradargrammetry has limited accuracy of topographic mapping due to the short spatial baseline（-100 km） and small intersection angle. In order to improve the performance and reliability of generating digital elevation model（DEM） from spaceborne SAR radargrammetry, an exploration of two-sided stereoradargrammetry from the combination of ascending and descending orbits with geometric configuration of long spatial baseline（-1000 km） was conducted in this study. The slant-range geometry between SAR sensors to the earth surface and the Doppler positioning equations were employed to establish the stereoscopic intersection model. The measurement uncertainty of two-sided radargrammetric elevation was estimated on the basis of radar parallax of homogeneous points between input SAR images. Two stereo-pairs of ALOS/PALSAR（Advanced Land Observing Satellite/Phased Array type L-band Synthetic Aperture Radar） acquisitions with the orbital separation almost 1080 km over the west Sichuan foreland basin with rolling topography in southwestern China were employed in the study to obtain the up-to-date terrain data after the 2008 Wenchuan earthquake that hit this area. Thequantitative accuracy assessment of two-sided radargrammetric DEM was performed with reference to field GPS observations. The experimental results show that the elevation accuracy reaches 5.5 m without ground control points（GCPs） used, and the accuracy is further improved to 1.5 m with only one GPS GCP used as the least constraint. The theoretical analysis and testing results demonstrate that the twosided long baseline SAR radargrammetry from the ascending and descending orbits can be a very promising technical alternative for large-area and high accuracy topographic mapping.

关键词： Ascending and descending orbits Twosided SAR radargrammetry Long baseline Image parallax Accuracy assessment

中国儿童青少年遗尿症患病率及影响因素的Meta分析

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中国全科医学 2025年第6期28卷 763-770,776页

作者：刘芹程敏江凤琼李小玉川北医学院护理学院四川省南充市637000 电子科技大学医学院附属绵阳医院绵阳市中心医院四川省绵阳市621000

背景遗尿症是儿科常见疾病之一,近年来,遗尿症对儿童青少年身心健康造成了极大的威胁,严重影响患儿的生活质量,给社会和家庭带来严重的负担。目前,关于儿童青少年遗尿症的影响因素还存在争议,且国内外鲜见相关的系统评价。目的利用Meta... 详细信息

背景遗尿症是儿科常见疾病之一,近年来,遗尿症对儿童青少年身心健康造成了极大的威胁,严重影响患儿的生活质量,给社会和家庭带来严重的负担。目前,关于儿童青少年遗尿症的影响因素还存在争议,且国内外鲜见相关的系统评价。目的利用Meta分析探讨国内儿童青少年遗尿症的患病率和影响因素。方法计算机检索中国知网(CNKI)、万方数据知识服务平台(Wanfang Data)、维普网(VIP)、中国生物医学文献服务系统(SinoMed)、PubMed、Embase、Web of Science、Cochrane Library数据库中的相关研究,检索时间从建库至2024年5月。由2名研究者独立筛选并交叉核对,横断面研究采用美国医疗保健研究与质量机构进行评估,采用Stata17.0软件进行Meta分析。结果共纳入27篇文献,包括243530例患儿。Meta分析结果显示,中国儿童青少年遗尿症患病率为6.1%(95%CI=5.1%~7.2%),其中,男性(OR=1.52,95%CI=1.41~1.64)、遗尿症家族史(OR=3.46,95%CI=2.01~5.93)、便秘(OR=2.32,95%CI=1.59~3.40)、尿路感染史(OR=2.33,95%CI=1.81~3.01)、睡眠障碍(OR=2.01,95%CI=1.10~3.67)、尿频(OR=1.90,95%CI=1.43~2.52)、尿急(OR=1.67,95%CI=1.31~2.12)、尿失禁(OR=4.85,95%CI=2.78~8.45)是儿童青少年遗尿症的危险因素(P<0.05);排尿训练(OR=0.11,95%CI=0.02~0.46)是儿童青少年遗尿症的保护因素(P<0.05)。结论中国儿童青少年遗尿症患病率较高,性别、遗尿症家族史、便秘、尿路感染史、排尿训练、睡眠障碍、尿频、尿急、尿失禁是儿童青少年遗尿症的主要影响因素。因此,未来应对儿童青少年遗尿症进行早期识别和干预,提高家长对遗尿症的重视,做好疾病宣教普及,减少遗尿症患病率,提高患儿及家庭生活质量。

关键词：遗尿遗尿症儿童青少年患病率影响因素 Meta分析

Mechanical properties of hot-pressed high-entropy diboride-based ceramics

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Journal of Advanced Ceramics 2020年第4期9卷 503-510页

作者： Ji-Xuan liu Xiao-qin Shen Yue Wu Fei Li Yongcheng Liang guo-Jun Zhang State Key Laboratory for Modification of Chemical Fibers and Polymer Materials College of Materials Science and EngineeringCollege of SciencesInstitute of Functional MaterialsDonghua UniversityShanghai201620China

High-entropy ceramics attract more and more attention in recent ***,mechanical properties especially strength and fracture toughness for high-entropy ceramics and their composites have not been comprehensively *** this work,high-entropy(Ti0.2Zr0.2Hf0.2Nb0.2Ta 0.2)B2(HEB)monolithic and its composite containing 20 vol%SiC(HEB–20SiC)are prepared by hot *** addition of SiC not only accelerates the densification process but also refines the microstructure of HEB,resulting in improved mechanical *** obtained dense HEB and HEB–20SiC ceramics hot pressed at 1800℃exhibit four-point flexural strength of 339±17 MPa and 447±45 MPa,and fracture toughness of 3.81±0.40 MPa·m1/2 and 4.85±0.33 MPa·m1/2 measured by single-edge notched beam(SENB)*** deflection and branching by SiC particles is considered to be the main toughening mechanisms for the HEB–20SiC *** hardness Hv0.2 of the sintered HEB and HEB–20SiC ceramics is 23.7±0.7 GPa and 24.8±1.2 GPa,*** the increase of indentation load,the hardness of the sintered ceramics decreases rapidly until the load reaches about 49 N,due to the indentation size *** on the current experimental investigation it can be seen that the room temperature bending strength and fracture toughness of the high-entropy diboride ceramics are within ranges commonly observed in structure ceramics.

关键词： high-entropy ceramics high-entropy diboride flexural strength fracture toughness indentation size effect

Design of A Bionic Spudcan and Analysis of Penetration and Extraction Performances for Jack-up Platform

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China Ocean Engineering 2020年第1期34卷 80-88页

作者： guo Sheng ZHUANG Hong TANG Wen-xian WU Wen-le liu qin WANG Yue-yang School of Mechanical Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China Jiangsu Provincial Key Laboratory of Advanced Manufacturing for Marine Mechanical Equipment Jiangsu University of Science and TechnologyZhenjiang 212003China

The mechanisms of soil structure interaction have drawn much attention in the past years in the installation and operation of jack-up platform. A bionic spudcan produced by biomimetic of egg and snail shell is proposed, and the performance of the penetration and extraction are analyzed by numerical method. The geometric contour of egg and snail shell is measured, and its mathematical model is established respectively. According to the structure of existing spudcan of jack-up platform, three kinds of typical biomimetic spudcan are designed. Furthermore, numerical analysis models of biomimetic spudcan are established respectively to study the soil structure interaction mechanism in the process of penetration and extraction, and contrastive analysis of resistance characteristics are carried out. To conclude, the results show that the biomimetic spudcan facilitates the platform installation, and it is also beneficial to the improvement of the bearing capacity of spudcan.

关键词： jack-up platform egg shell snail shell bionic design spudcan soil structure interaction

Anatomical Study on the Multi-Ovule Development and Abortion of Hanfu Apple

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Journal of Integrative Agriculture 2014年第4期13卷 770-777页

作者： YANG Xu-yuan MA Huai-yu liu guo-cheng Lü De-guo qin Si-jun DU guo-dong College of Horticulture Shenyang Agricultural University/Key Laboratory for Northern Fruit Trees Cultivation and Physio-Ecology of Shenyang City

The terminal flower buds of 6-yr-old Hanfu apple were used to study the ovule development, ovular characteristics, cell death of abortive ovules, and dynamic change of starch grain quantity in the embryo sac with paraffin slices and terminal deoxynucleotidyl transferase-mediated fluorescein deoxyuridine triphosphate nick-end labeling （TUNEL） system. Four anatropous ovules in each ventricle could be observed before flowering. With the developing of floral organ, the bulk of normal ovules enlarged in each ventricle, the mature embryo sac differentiated into nucellus, and the egg cell developed into zygote by double fertilization. A large number of starch grains were observed during pollen tube growth and double fertilization, which guaranteed basic nutrient supply in the normal development of ovules. Moreover, abortion phenomenon of runtish ovules emerged at the stages of mature embryo sac, double fertilization and zygote development. The abortion characteristics included deformity of ovule development, degradation of nucellus tissue, separation between funiculus and ovule, abnormality of four-nucleate embryo sac, as well as development interruption of mature embryo sac. TUNEL analysis proved that ovule abortion was programmed cell death.

关键词： Hanfu apple multi-ovule abortion programmed cell death starch grain

Investigation on the dynamic behavior of cloud cavitation around a flexible hydrofoil

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Journal of Hydrodynamics 2023年第4期35卷 712-723页

作者： Yun-qing liu Wei Zhao Zhi Pan Zhi-pu guo Rui Yuan qin Wu School of Mechanical Engineering Beijing Institute of TechnologyBeijing100081China Wuhan Second Ship Design and Research Institute Wuhan430205China

The objective of this paper is to investigate the dynamic behavior of cloud cavitating flow around a flexible hydrofoil with experimental and numerical *** tightly coupled fluid-structure interaction(FSI)modeling is applied and validated with the experimental *** Q-criterion andω-criterion are applied to illustrate the interaction between the vortex structures and *** flexibility is seen to result in nose-up twist deformation,causing a reduction of the shedding frequency from an increase in the attached cavity *** to the flexibility,the fluctuation of load coefficients of the flexible hydrofoil is larger than that of the rigid ***,the re-entrant jet propagation speed of the flexible hydrofoil is greater than that of the rigid *** shed cloud cavity is observed to be uniform along the flexible hydrofoil span under the combined influence of the strong vibration and the gap flow.

关键词： Cloud cavitation fluid-structure interaction(FSI) vortex structures flexible hydrofoil