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基于组织特征的挤压铸造A356合金局部力学性能研究

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铸造 2024年第3期73卷 303-312页

作者：马万里赵海东王雪灵杨鹏黄智华南理工大学国家金属材料近净成形工程技术研究中心机械与汽车工程学院广东广州510640 山东宏和轻量化科技有限公司山东邹平256200

采用基于微观组织特征的有限元分析(FEA),计算了A356挤压铸件不同部位的力学性能。通过不同分析域尺寸、网格尺寸和FEA模型的分析,确定了合适的有限元模型,使用试验拉伸结果对FEA结果进行了验证,探讨了组织特征对性能的影响。结果表明,S... 详细信息

采用基于微观组织特征的有限元分析(FEA),计算了A356挤压铸件不同部位的力学性能。通过不同分析域尺寸、网格尺寸和FEA模型的分析,确定了合适的有限元模型,使用试验拉伸结果对FEA结果进行了验证,探讨了组织特征对性能的影响。结果表明,Si粒子长度和形状因子增大,抗拉强度与伸长率均呈下降趋势;Si粒子的密度和面积分数的增大,抗拉强度提高和伸长率降低;A356合金的损伤演化过程可分为Si粒子断裂(微裂纹的形成)、裂纹的扩展和连接三个阶段;Si粒子小而圆整且分布较均匀时,局部力学性能各向异性小,Si粒子长宽比较大且呈现出明显的方向性时,局部力学性能各向异性加大。

关键词： A356合金挤压铸造组织特征有限元分析力学性能

汉北河流域强人类活动影响下的暴雨洪水模拟方法

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长江科学院院报 2024年第7期41卷 72-78,93页

作者：黄曼丽吴凤燕翁朝晖丁俊芝马婉丽黄雍徐静李海建湖北省水利水电规划勘测设计院有限公司武汉430064 湖北省水利水电科学研究院湖北省国际灌排研究培训中心武汉430070 鄂北地区水资源配置工程建设与管理局(筹) 武汉430064

为了研究人类活动影响下丘陵到平原区流域洪水模拟的关键问题,包括流域内降雨空间分布不均、丘陵平原产汇流差异大、下垫面受水利工程建设和调度影响等复杂边界条件,并提出相应的解决办法和模型,以汉北河为例,将大流域划分为11个单元,... 详细信息

为了研究人类活动影响下丘陵到平原区流域洪水模拟的关键问题,包括流域内降雨空间分布不均、丘陵平原产汇流差异大、下垫面受水利工程建设和调度影响等复杂边界条件,并提出相应的解决办法和模型,以汉北河为例,将大流域划分为11个单元,通过分析场次暴雨在各单元的空间分布解决降雨空间不均的问题;各单元根据各自下垫面条件进行API水文模型参数的率定,解决了丘陵平原产汇流差异大的问题,提高了模型参数与实际情况的贴合度。在模型中,将河流改道、水库、蓄滞洪区、水闸、泵站建设和调度、土地利用等人类活动对汇流的影响纳入物理模型和产汇流模拟中,以便构建符合实际调度的下垫面产汇流体系。模拟计算的洪峰的纳什系数NSE均在0.85以上,模拟结果表明洪峰流量、水位及峰现时间与实测值吻合良好。

关键词：暴雨洪水模拟水文水动力嵌套耦合模型汉北河流域人类活动影响

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肛周脓肿术后切口感染病原菌及其危险因素

中华医院感染学杂志 2024年第11期34卷 1702-1705页

作者：王祥盛胡冰辉马万里卢秀芬张晓明李凤盛王炳杰邢台市人民医院肛肠外科河北邢台054000 邢台市人民医院整形烧伤科河北邢台054000 邢台市信都区人民医院普外科河北邢台054000

目的探讨肛周脓肿术后切口感染病原菌及其危险因素.方法选取2020年1月-2022年12月于邢台市人民医院行肛周脓肿切开引流术患者115例,根据术后切口感染情况分为感染组和非感染组,分别为34例、81例;统计肛周脓肿患者术后切口感染的病原菌... 详细信息

目的探讨肛周脓肿术后切口感染病原菌及其危险因素.方法选取2020年1月-2022年12月于邢台市人民医院行肛周脓肿切开引流术患者115例,根据术后切口感染情况分为感染组和非感染组,分别为34例、81例;统计肛周脓肿患者术后切口感染的病原菌及其耐药性;分析两组临床资料,通过Logistic分析法对肛周脓肿患者术后切口感染危险因素进行归纳.结果肛周脓肿术后切口感染患者共培养分离病原菌51株,其中革兰阴性菌31株占60.78%,革兰阳性菌20株占39.22%,以大肠埃希菌、金黄色葡萄球菌和铜绿假单胞菌为主;大肠埃希菌对头孢曲松和哌拉西林耐药率较高,亚胺培南较敏感;金黄色葡萄球菌对青霉素和红霉素耐药率较高,万古霉素和替考拉宁较敏感;铜绿假单胞菌对头孢他啶和头孢曲松耐药率较高,环丙沙星较敏感;Logistic回归分析结果显示,住院时间、深部脓肿、肛周皮肤感染灶是肛周脓肿患者术后切口感染的危险因素(P<0.05).结论肛周脓肿患者术后切口感染病原菌以大肠埃希菌、金黄色葡萄球菌、铜绿假单胞菌为主;临床可根据危险因素对患者行针对性治疗和干预,以减少肛周脓肿患者术后切口感染风险.

关键词：肛周脓肿切口感染病原菌耐药性危险因素

A Review on Vibration Control of Multiple Cylinders Subjected to FlowInduced Vibrations

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China Ocean Engineering 2024年第2期38卷 183-197页

作者： XU wan-hai ma Ye-xuan State Key Laboratory of Hydraulic Engineering Intelligent Construction and Operation Tianjin UniversityTianjin 300350China Institute of Mechanics Chinese Academy of SciencesBeijing 100190China

The fatigue damage caused by flow-induced vibration(FIV)is one of the major concerns for multiple cylindrical structures in many engineering *** FIV suppression is of great importance for the security of many cylindrical *** active and passive control methods have been employed for the vibration suppression of an isolated cylinder undergoing vortex-induced vibrations(VIV).The FIV suppression methods are mainly extended to the multiple cylinders from the vibration control of the isolated *** to the mutual interference between the multiple cylinders,the FIV mechanism is more complex than the VIV mechanism,which makes a great challenge for the FIV *** efforts have been devoted to vibration suppression of multiple cylinder systems undergoing FIV over the past two *** control methods,such as helical strakes,splitter plates,control rods and flexible sheets,are not always effective,depending on many influence factors,such as the spacing ratio,the arrangement geometrical shape,the flow velocity and the parameters of the vibration control *** FIV response,hydrodynamic features and wake patterns of the multiple cylinders equipped with vibration control devices are reviewed and *** FIV suppression efficiency of the vibration control methods are analyzed and compared considering different influence *** research on the FIV suppression of multiple cylinders is suggested to provide insight for the development of FIV control methods and promote engineering applications of FIV control methods.

关键词： flow-induced vibration vibration control multiple cylinders tandem side-by-side staggered

Synthesis,Characterization of Polyethylene Ionomers and Their Antibacterial Properties

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Chinese Journal of Polymer Science 2024年第8期42卷 1077-1084页

作者： Jia-Jia Wu Fei wang Peng-Qi wan li Pan Chun-Sheng Xiao Zhe ma Yue-Sheng li Tianjin Key Lab Composite&Functional materials School of Materials Science and EngineeringTianjin UniversityTianjin 300350China Key Lab Polymer Ecomaterials Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China

Owing to its high production volume and wide range of application s,polyethylene has gained a great deal of attention,but its low surface energy and non-polar nature have limited its application in some important *** this study,ethylene/11-iodo-1-undecene copolymers were prepared and used as the intermediates to afford a series of imidazolium-based ionomers bearing methanesulfonate(CH_(3)SO_(3)^(-)),trifluoromethanesulfonate(CF_(3)SO_(3)^(-)),or bis(trifluoromethane)sulfonimide(Tf_(2)N^(-))*** tensile test results showed that the stress-at-break(7.8-25.6 MPa)and the elongation-at-break(445%-847%)of the ionomers could be adjusted by changing the counterion species and the ionic group *** importantly,the ionomers exhibited marvelous antibacterial activities against Staphylococcus aureus(***)and Escherichia coli(***).The ionomers bearing Tf_(2)N^(-)exhibited antibacterial activities>99%against both *** and *** when ionic content reached 9.1%.The imidazolium-based ionomers prepared in this work demonstrated excellent comprehensive properties,especially highefficient and broad-spectrum antibacterial ability,exhibiting the potential fo r the application as the antibacterial materials in packaging,medical,and other fields.

关键词： Polyethylene Ionomer Polymerization catalysis Imidazolium Antibacterial material

肛周脓肿多重耐药菌感染危险因素及其预测模型构建

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中华医院感染学杂志 2024年第9期34卷 1370-1373页

作者：胡冰辉王祥盛马万里卢秀芬霍军月张晓明王炳杰邢台市人民医院肛肠外科河北邢台054000 邢台市人民医院烧伤整形科河北邢台054000

目的探讨肛周脓肿患者多重耐药菌感染的危险因素,构建风险预测模型,分析其预测价值。方法选取2020年1月-2022年12月邢台市人民医院收治的108例肛周脓肿患者,根据肛周脓肿患者检出病原菌分组,分为多重耐药菌感染组31例、非多重耐药菌感染... 详细信息

目的探讨肛周脓肿患者多重耐药菌感染的危险因素,构建风险预测模型,分析其预测价值。方法选取2020年1月-2022年12月邢台市人民医院收治的108例肛周脓肿患者,根据肛周脓肿患者检出病原菌分组,分为多重耐药菌感染组31例、非多重耐药菌感染组77例,多因素Logistic回归分析肛周脓肿患者多重耐药菌感染的危险因素,建立风险预测模型,受试者工作特征(ROC)曲线分析模型的预测价值。结果共分离出病原菌112株,其中革兰阴性菌(108株,96.43%),革兰阳性菌(4株,3.57%),112株病原菌中多重耐药菌31株占比27.68%,包括产超广谱β-内酰胺酶肺炎克雷伯菌6株和大肠埃希菌24株及耐甲氧西林金黄色葡萄球菌(MRSA)1株;合并糖尿病、既往反复发作史、使用抗菌药物种类多是肛周脓肿患者多重耐药菌感染危险因素(OR=1.732;1.970;2.347,P<0.05),构建的风险预测模型诊断价值较高,曲线下面积(AUC)值为0.874(95%CI为0.796~0.930),敏感度为64.50%,特异度为93.50%。结论肛周脓肿患者革兰阴性菌感染居多,多重耐药菌占比较高;肛周脓肿患者多重耐药菌感染与合并糖尿病、既往反复发作史、抗菌药物使用种类相关,据此建立的风险预测模型诊断价值较高。

关键词：肛周脓肿病原菌多重耐药菌危险因素模型构建受试者工作特征曲线

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Topological magnetoelectric response in ferromagnetic axion insulators

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National Science Review 2024年第2期11卷 8-14页

作者： Yuhao wan Jiayu li Qihang liu Department of Physics and Shenzhen Institute for Quantum Science and Engineering(SIQSE) Southern University of Science and Technology Shenzhen Key Laboratory of Advanced Quantum Functional materials and Devices Southern University of Science and Technology Guangdong Provincial Key Laboratory for Computational Science and material Design Southern University of Science and Technology

The topological magnetoelectric effect （TME） is a hallmark response of the topological field theory,which provides a paradigm shift in the study of emergent topological ***,its direct observation is yet to be realized due to the demanding magnetic configuration required to gap all surface ***,we theoretically propose that axion insulators with a simple ferromagnetic configuration,such as the MnBi2Te4/（Bi2Te3）nfamily,provide an ideal playground to realize the *** the designed triangular prism geometry,all the surface states are magnetically *** a vertical electric field,the surface Hall currents give rise to a nearly half-quantized orbital moment,accompanied by a gapless chiral hinge mode circulating in ***,the orbital magnetization from the two topological origins can be easily distinguished by reversing the electric *** work paves the way for direct observation of the TME in realistic axion-insulator materials.

关键词： topological magnetoelectric effect axion insulator magnetic topological materials

Vibration Control of A Flexible marine Riser System Subject to Input Dead Zone and Extraneous Disturbances

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China Ocean Engineering 2024年第2期38卷 271-284页

作者： ZHOU li wanG Guo-rong wan Min School of Mechatronic Engineering Southwest Petroleum UniversityChengdu 610500China Energy Equipment Institute Southwest Petroleum UniversityChengdu 610500China National Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu 610500China

An observer-based adaptive backstepping boundary control is proposed for vibration control of flexible offshore riser systems with unknown nonlinear input dead zone and uncertain environmental *** control algorithm can update the control law online through real-time data to make the controller adapt to the environment and improve the control ***,based on the adaptive backstepping framework,virtual control laws and Lyapunov functions are designed for each *** direction interference observers are designed to track the timevarying boundary *** this basis,the inverse of the dead zone and linear state transformation are used to compensate for the original system and eliminate the adverse effects of the dead *** addition,the stability of the closed-loop system is proven by Lyapunov stability *** the system states are bounded,and the vibration offset of the riser converges to a small area of the initial ***,four examples of flexible marine risers are simulated in maTLAB to verify the effectiveness of the proposed controller.

关键词： adaptive backstepping control disturbance observer flexible marine riser input dead zone vibration control

Effects of Lactobacillus paracasei N1115 on gut microbial imbalance and liver function in patients with hepatitis B-related cirrhosis

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World Journal of Gastroenterology 2024年第11期30卷 1556-1571页

作者： Yan-Chao Hu Xiang-Chun Ding Hui-Juan liu wan-Long ma Xue-Yan Feng li-Na ma Department of Infectious Disease General Hospital of Ningxia Medical UniversityYinchuan 750004Ningxia Hui Autonomous RegionChina Infectious Disease Clinical Research Center of Ningxia Yinchuan 750004Ningxia Hui Autonomous RegionChina

BACKGROUND Hepatitis B cirrhosis(HBC)is a chronic disease characterized by irreversible diffuse liver damage and aggravated by intestinal microbial imbalance and metabolic *** the relationship between certain single probiotics and HBC has been explored,the impact of the complex ready-to-eat Lactobacillus paracasei N1115(LP N1115)supplement on patients with HBC has not been *** To compare the changes in the microbiota,inflammatory factor levels,and liver function before and after probiotic treatment in HBC *** This study included 160 HBC patients diagnosed at the General Hospital of Ningxia Medical University between October 2018 and December *** were randomly divided into an intervention group that received LP N1115 supplementation and routine treatment and a control group that received routine treatment *** samples were collected at the onset and conclusion of the 12-wk intervention *** structure of the intestinal microbiota and the levels of serological indicators,such as liver function and inflammatory factors,were *** Following LP N1115 intervention,the intestinal microbial diversity significantly increased in the intervention group(Pliver function indices and significantly lower levels of inflammatory factors(Pliorating intestinal microbial imbalance in HBC patients by modulating the structure of the intestinal microbiota,improving liver function,and reducing inflammatory factor levels.

关键词： Hepatitis B cirrhosis N1115 ready-to-eat lactobacillus Inflammation liver function Lachnospiraceae incertae sedis Probiotic