检索结果-南通市图书馆

Additive manufacturing of multi-morphology graded titanium scaffolds for bone implant applications

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2023年第8期139卷 47-58页

作者： Aihua Yu Ce zhang Wei Xu Yun zhang Shiwei Tian Bowen Liu Jiazhen zhang Anrui He Bo Su Xin Lu Shunde Graduate School of University of Science and Technology Beijing Foshan 528399China National Engineering Research Center for Advanced Rolling and Intelligent Manufacturing Institute of Engineering TechnologyUniversity of Science and Technology BeijingBeijing 100083China Beijing Advanced Innovation Center for Materials Genome Engineering State Key Laboratory for Advanced Metals and MaterialsUniversity of Science and Technology BeijingBeijing 100083China National Engineering Technology Research Center of Flat Rolling Equipment Institute of Engineering TechnologyUniversity of Science and Technology BeijingBeijing 100083China Bristol Dental School University of BristolBristol BS12LYUK

Porous Titanium scaffolds have attracted widespread attention as bone implants for avoiding the stress shielding effect and promoting *** this study,multi-morphology graded scaffolds hy-bridized by Primitive and Gyroid structures with porosity of 50,60,and 70%were designed(denoted as PG50,PG60,and PG70,respectively)and fabricated by selective laser *** simulation results showed that the maximum von-Mises stress of hybridized scaffolds increased from 504.22 to 884.24 MPa with *** permeability and average pore size of multi-morphology PG50,PG60,and PG70 were in the range of 3.58×10^(-9)-5.50×10^(-9) m^(2) and 568.1-758.4μm,*** microstructure of multi-morphology graded scaffolds consisted of a fully martensiticα′*** permeabilities of PG50 and PG60 were 3.27×10^(-9) and 4.35×10^(-9) m^(2),respectively,which were within the range of human bone(0.01-12.1×10^(-9) m^(2)).Elastic modulus and compressive yield strength of PG50 and PG60 ranged within 5.93^(-9).86 and 180.06-257.08 MPa,***,the PG50 not only exhibited a similar elastic modulus compared to human cortical bone(10.1 GPa)but also had higher strength(257.08 vs 131 MPa).The results of in vitro biocompatibility assay showed that PG50 and PG60 have better cyto-compatibility than mono-morphology scaffolds with the same *** together,PG50 is promising to be used for the restoration of bone defects due to its excellent mechanical properties,appropriate per-meability,and good cytocompatibility.

关键词： Bone implants Multi-morphology graded titanium scaffolds Finite element analysis Selective laser melting Cytocompatibility

环氧树脂粘度和充磁次数对两步室温压各向异性粘结Nd-Fe-B磁体性能的影响

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

中国稀土学报 2024年第4期42卷 705-711,I0003页

作者：马斌张鹏杰王继全李青华李炳山孙威矿冶科技集团有限公司北京102600 北矿磁材(阜阳)有限公司安徽阜阳236000

采用两步室温压工艺即室温预成型+高温取向成型制备各向异性粘结Nd-Fe-B磁体,研究了环氧树脂粘度和交变磁场充磁次数对磁体性能的影响。环氧树脂在140℃时粘度较小(约150 Pa·s)且具有一个较长的低粘度平台(约200 s),预成型坯体在140℃... 详细信息

采用两步室温压工艺即室温预成型+高温取向成型制备各向异性粘结Nd-Fe-B磁体,研究了环氧树脂粘度和交变磁场充磁次数对磁体性能的影响。环氧树脂在140℃时粘度较小(约150 Pa·s)且具有一个较长的低粘度平台(约200 s),预成型坯体在140℃保温1 min时预热效果最好,制备的粘结磁体具有最高的最大磁能积((bh)_(max))、取向度(DOA)和密度(127 kJ·m^(-3),0.55,5.91 g·cm^(-3))。140℃保温1 min时,粘结磁体(bh)_(max),DOA在交变磁场充磁2次时达到最大值(133 kJ·m^(-3)、0.59);140℃保温6 min时,粘结磁体(bh)_(max),DOA在交变磁场充磁4次时达到最大值(108 kJ·m^(-3)、0.52);密度则随着交变磁场充磁次数的增加逐渐降低。随着保温时间的延长,环氧树脂粘度增大,流动性降低,导致粘结磁体(bh)_(max),DOA和密度降低,可以通过增加交变磁场充磁次数使粉末颗粒向磁场方向转动来提高磁体DOA,进而提高(bh)_(max)。

关键词：粘结Nd-Fe-B磁体环氧树脂粘度交变磁场

在线全文

学校读者我要写书评

暂无评论

埋地CO_(2)管道泄漏扩散特征研究进展

油气储运 2024年第5期43卷 500-509页

作者：张俊朋苗青荆少东王永胜欧阳欣范振宁梁海宁张建中石化石油工程设计有限公司·中国石化碳捕集、利用与封存(CCUS)重点实验室国家管网集团科学技术研究总院分公司中石化石油工程建设有限公司

[目的]CO_(2)管道输送是碳捕集、利用与封存(Carbon Capture, Utilization and Storage, CCUS)技术产业链中的关键环节,其在运行过程中存在意外泄漏风险。相比于地上管道,受土壤阻力的影响,埋地高压管道的泄漏扩散机制更加复杂。然而,... 详细信息

[目的]CO_(2)管道输送是碳捕集、利用与封存(Carbon Capture, Utilization and Storage, CCUS)技术产业链中的关键环节,其在运行过程中存在意外泄漏风险。相比于地上管道,受土壤阻力的影响,埋地高压管道的泄漏扩散机制更加复杂。然而,目前对于CO_(2)管道泄漏扩散特征的研究综述主要聚焦于地上管道泄漏的场景。[方法]针对埋地管道小孔泄漏与全尺寸断裂两种常见场景,基于文献调研对目前埋地管道泄漏扩散的实验与模拟研究现状进行梳理评述,探究了土壤地质条件、土壤温度、外界压力以及外界风速对CO_(2)气体土壤渗流扩散过程中的影响,并总结了当前模拟埋地CO_(2)管道全断裂泄漏扩散的建模方式与物理模型。[结果]对于埋地CO_(2)管道小孔泄漏近场泄漏源特征,主要以开展小型实验的方式研究泄漏口附近土壤温度变化以及干冰层、冻土层的增长规律。对于埋地CO_(2)管道小孔泄漏远场扩散特征的模拟研究,大多假设土壤孔隙度不发生变化,并未考虑流体相变与冲击压力对土壤孔隙度的影响。埋地管道全尺寸断裂条件下气体射流扩散的研究主要以模拟为主,且大多数模型直接以形成的洞坑为物理原型,未考虑洞坑形成对气体射流扩散的影响。[结论]埋地CO_(2)管道全尺寸断裂的现场测试和小孔泄漏扩散理论模型建立仍有很大发展空间,建议通过专项攻关完善地质条件和外界环境影响下CO_(2)气体在土壤中的扩散机制,加大投入开展埋地CO_(2)管道大孔径或者全尺寸断裂泄漏扩散试验,获取更多实验数据,以建立更加全面准确的数学物理模型。

关键词：埋地管道 CO_(2) 泄漏扩散土壤数值模拟

Influence of Tourists′ Environmental Tropisms on Their Attitudes to Tourism and Nature Conservation in Natural Tourist Destinations: A Case Study of Jiuzhaigou National Park in China

在线全文

学校读者我要写书评

暂无评论

Chinese Geographical Science 2011年第3期21卷 377-384页

作者： CHENG Shaowen zhang Jie LU Shaojing XU Feifei zhang Honglei School of City and Environment Science Huazhong Normal University Wuhan 430074 China School of Geographic and Oceanographic Sciences Nanjing University Nanjing 210093 China School of Service Management Bournemouth University Bournemouth BH12 5BB UK

People′s environmental tropism has an effect on their understanding of tourism-nature relationship,and also influences their attitudes to natural resources utilization and environmental *** Jiuzhaigou National Park of China as a study case,the authors conducted some quantitative analyses with the tools of SPSS 16.0 and LISREL 8.7,to explore the influence of tourists′ environmental tropism on their attitudes to tourism and nature conservation in the natural tourist *** hypotheses and the theoretic model of influences of tourists′ environmental tropism on their attitudes to tourism and nature conservation have been tested and accepted based on the Structural Equation Model analysis on survey data collected in Jiuzhaigou National Park of *** conclusions were drawn as follows: 1) tourists′ human-prioritized concept influences their cognition to tourism-nature *** concept has a positive influence on their supportive attitudes to tourism,but a negative influence on their attitudes to nature conservation;2) tourists′ human-nature coordination concept has a positive influence on their supportive attitudes to both tourism and nature conservation,especially to the *** paper generally proves that human′s environmental tropism does have an influence on their attitudes to tourism and nature conservation in natural tourist destinations.

关键词： environmental tropism nature conservation natural tourist destination tourism-nature relationship Jiuz- haigou National Park

Flavonoids of Rosa rugosa *** tumor proliferation and metastasis in human hepatocellular carcinoma HepG2 cells

在线全文

学校读者我要写书评

暂无评论

Food Science and Human Wellness 2022年第2期11卷 374-382页

作者： Zhiguo zhang Meilin Wang Shu Xing Chen zhang School of Food Science and Engineering Qilu University of Technology(Shandong Academy of Sciences)Jinan 250353China School of Chemistry and Pharmaceutical Engineering Qilu University of Technology(Shandong Academy of Sciences)Jinan 250353China School of Science The Hong Kong University of Science and TechnologyHong KongChina

Rosa rugosa *** recognized as both medicine and edible in *** article investigated the antitumor activity of rose ***-extracted rose flavonoids(RFW)and ethanol-extracted rose flavonoids(RFE)were achieved by extracting with distilled water and 70%ethanol,*** effects of the two extracts on proliferation inhibition,apoptosis inducement and metastasis prevention of human HepG2 hepatocellular carcinoma cell lines were tested,via optical/fluorescence microscopy,MTT detection,Transwell assay,flow cytometry and Western blot,*** results indicated that rose flavonoids at low concentration(10-40μg/mL)had a better inhibitory effect on migration and invasion of HepG2 cells in a dose-dependent manner,while rose flavonoids at high concentration(80-160μg/mL)could induce apoptosis of HepG2 cells by up-regulating the expression of pro-apoptotic proteins p53 and Bax,and down-regulating the expression of anti-apoptotic proteins Bcl-2,leading to the functioning of caspase-3 and *** effect of RFE at the same concentration was significantly better than that of ***,this study found that rose flavonoids had a certain inhibitory effect on proliferation and metastasis of human liver cancer cells HepG2,indicating the application of rose flavonoids in preventing and treating of liver cancer.

关键词： Rose flavonoids Tumor metastasis Apoptosis Human liver cancer

Morphology and magnetic properties of Sm_(2)Co_(7)/α-Fe nanocomposite magnets produced by high energy ball milling and spark plasma sintering

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2021年第3期39卷 312-316,I0003页

作者： Yitong Zhuge Yuqing Li Xiaochang Xu Dongtao zhang Hongguo zhang Weiqiang Liu Ming Yue Key Laboratory of Advanced Functional Materials Ministry of Education of ChinaCollege of Materials Science and EngineeringBeijing University of TechnologyBeijing 100124China

In this article,the Sm_(2)Co_(7)/α-Fe nanocomposite magnets were prepared by high energy ball milling and spark plasma sintering *** effect of soft phase content on the magnetic properties was *** to 30 wt% α-Fe was added into Sm_(2)Co_(7) matrix without the decrease of *** energy product(bh)max of 9.2 MGOe was obtained with 20 wt% α-*** observation shows that the grain size of α-Fe is 20-50 nm which ensures a good coupling effect between soft and hard *** more thing needs to be mentioned is that there exists inter-diffusion between Sm-Co phase and α-Fe ***,our results can also illustrate that the Sm_(2)Co_(7)/α-Fe nanocomposite magnets are able to acquire better magnetic properties than the SmCo_(5)/α-Fe magnets prepared by the same process due to the large domain width of Sm_(2)Co_(7) phase.

关键词： Nanocomposite magnet Microstructure Interdiffusion Exchange coupling effect Spark plasma sintering Rare earths

烧结工艺对2:17型SmCo合金磁性能的影响探究

在线全文

学校读者我要写书评

暂无评论

内蒙古科技大学学报 2024年第2期43卷 123-128页

作者：张晨李岩吕科任少卿张中烨赵明静内蒙古科技大学材料科学与工程学院内蒙古包头014010 包头稀土研究院白云鄂博稀土资源研究与综合利用国家重点实验室内蒙古包头014030 浙江大学材料科学与工程学院浙江杭州310030 山东建筑大学理学院山东济南250101

采用传统粉末冶金工艺制备了2∶17型SmCo合金,研究了烧结温度1195~1210℃对磁体微观结构和磁性能的影响。烧结态磁体主要由2∶17H相和1∶5H相组成。随烧结温度的升高,相组成不变,而晶粒平均粒径由43.51μm生长至75.71μm。从1195℃提升... 详细信息

采用传统粉末冶金工艺制备了2∶17型SmCo合金,研究了烧结温度1195~1210℃对磁体微观结构和磁性能的影响。烧结态磁体主要由2∶17H相和1∶5H相组成。随烧结温度的升高,相组成不变,而晶粒平均粒径由43.51μm生长至75.71μm。从1195℃提升至1210℃的过程中,剩磁B_(r)、内禀矫顽力H_(cj)、最大磁能积(bh)_(max)和密度ρ均随温度的升高先增大后减小,并在1200℃时得到了B_(r)=11.12 kGs、ρ=8.2747 g/cm^(3)的最佳烧结态磁体,同时磁体内铜元素分布相对均匀,磁体获得高磁性能。对比终态磁性能,发现剩磁B_(r)和密度ρ的提升主要完成于烧结阶段。

关键词： 2:17型SmCo永磁材料烧结温度磁性能微观组织结构

DP900钢的成形性及预应变对烘烤硬化行为的影响

在线全文

学校读者我要写书评

暂无评论

塑性工程学报 2024年第9期31卷 190-196页

作者：滕敦波张德军贾大伟徐志远烟台南山学院智能科学与工程学院山东烟台265700 山东南山铝业股份有限公司山东烟台265713

对汽车结构件用DP900钢的成形极限图进行了测试和研究,并运用数学模型进行了预测分析。利用内耗仪和透射电子显微镜从微观角度研究了预应变对烘烤硬化值的影响。结果表明:DP900钢室温下的力学性能为屈服强度604 MPa,抗拉强度935 MPa,均... 详细信息

对汽车结构件用DP900钢的成形极限图进行了测试和研究,并运用数学模型进行了预测分析。利用内耗仪和透射电子显微镜从微观角度研究了预应变对烘烤硬化值的影响。结果表明:DP900钢室温下的力学性能为屈服强度604 MPa,抗拉强度935 MPa,均匀伸长率达到14%,断后伸长率为19%。冲压成形过程中,成形极限FLD0为0.245,基于Hollomon方程建立的成形极限数学模型的预测误差在0.2%~13.5%,平均误差为5.87%。预应变量的大小对bh值有显著的影响。随预应变增大,bh值先升高后降低,预应变为7%时达到最高值45 MPa。内耗峰值变化趋势与bh值一致。

关键词：成形性烘烤硬化微观组织预应变

乳酸菌发酵对荞麦壳多酚组成及胃肠消化、酵解特性的影响

在线全文

学校读者我要写书评

暂无评论

中国食品学报 2024年第4期24卷 54-68页

作者：张志红陈志健王舒瑜刘玲玲关桦楠范松涛江苏科技大学粮食学院江苏镇江212100 江苏大学食品与生物工程学院江苏镇江212013

目的:探究乳酸菌HH-LP56发酵荞麦壳的酚类组成、胃肠道消化及结肠酵解特性。方法:用乳酸菌发酵处理荞麦壳,根据发酵过程中pH、总酚含量及抗氧化活性变化,筛选代表性样品,采用液相色谱法分析代表性样品的主要酚类物质结合方式及含量;采用... 详细信息

目的:探究乳酸菌HH-LP56发酵荞麦壳的酚类组成、胃肠道消化及结肠酵解特性。方法:用乳酸菌发酵处理荞麦壳,根据发酵过程中pH、总酚含量及抗氧化活性变化,筛选代表性样品,采用液相色谱法分析代表性样品的主要酚类物质结合方式及含量;采用Infogest 2.0体外胃肠消化,评价酚类的生物可及情况;进一步接种人粪便模拟结肠厌氧酵解,分析产气量、pH和短链脂肪酸(SCFA)。结果:乳酸菌发酵6 h(LP-6h)后总酚含量显著增加,发酵24 h(LP-24h)后进一步增加,并在发酵48 h(LP-48h)时总酚含量达到最高水平(7.32 mg/g)。分析未发酵(Raw)和发酵荞麦壳的酚类组成和存在形式发现,LP-6h,LP-24h和LP-48h中游离态没食子酸(142.88~145.87 mg/kg)和原儿茶酸(103.30~113.61 mg/kg)的含量显著高于Raw组(P<0.01),且肠道生物可及性明显增加。体外接种5位志愿者粪便菌群模拟结肠酵解发现,未发酵和发酵荞麦壳的产气量、主要SCFA和支链脂肪酸(BCFA)含量总体上均较为接近。其中3位志愿者的粪便微生物酵解荞麦壳48 h后,总SCFA含量均显著高于未发酵荞麦壳(P<0.01或P<0.05)。结论:乳酸菌发酵能有效改善荞麦壳的胃肠消化和酵解特性,研究结果将为乳酸菌发酵用于荞麦壳精深加工提供理论依据。

关键词：乳酸菌发酵荞麦副产物体外消化模拟结肠酵解