检索结果-南通市图书馆

Laser Surface Alloying of Low Carbon Steel Using High-entropy Alloy Precursors

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2016年第11期23卷 1195-1199页

作者： Xiao-tao LIU Wen-bin LEI Qun-jiao WANG wei-ping tong Chang-sheng LIU Jian-zhong CUI Key Laboratory of Electromagnetic Processing of Materials of Ministry of Education Northeastern University School of Materials Science and Engineering Northeastern University

The Al0. 5CoCrCuFeNi high-entropy alloy powders with simple face-centered-cubic （FCC） solid solution structure were introduced into the surface layer of a low carbon steel during laser surface alloying. A high performance surface layer with extremely fine martensite as the dominant phase was obtained, resulting in a great improvement in microhardness, wear resistance, and corrosion resistance. The great enhancement of microhardness and wear resistance of the laser alloyed layer is mainly due to the formation of extremely fine martensite hard phase, the solid solution strengthening of the alloying e!.ements in supersaturated a-Fe solid solution, and the existence of size effect and strain effect under rapid solidification. The enhancement of corrosion resistance is due to the alloying of Al, Co, Ni, Cr and Cu in the laser alloyed layer.

关键词： laser surface alloying high-entropy alloy hardness wear corrosion

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2015年第6期28卷 725-732页

作者： Lei Li Bo Xu wei-ping tong Hui Zhang Chun-Yan Ban Li-Zi He Zhi-Hao Zhao Yu-Bo Zuo Qing-Feng Zhu Jian-Zhong Cui Key Laboratory of Electromagnetic Processing of Materials Ministry of Education Northeastern University School of Metallurgy and Energy Hebei United University

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid （Pb）/ liquid （Sn） diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field （〈0.3 T）. When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level （0.8-5 T）, the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.

关键词： Microstructural evolution Crystallization behavior Dendrite growth Diffusion behavior Magnetic field Solidification pattern

在线全文

学校读者我要写书评

暂无评论

二级摆型吊车系统动态及基于无源的控制

系统仿真学报 2008年第18期20卷 4945-4948页

作者：郭卫平刘殿通烟台大学计算机学院山东烟台264005

吊车系统由于吊钩质量的存在而呈现二级摆特性。利用拉格朗日力学原理建立了二级摆型吊车系统的动态模型,分析了系统具有的特性如无源性和固有频率,提出了一种基于无源的控制方法并证明了系统的稳定性。仿真结果验证了二级摆型吊车系统... 详细信息

吊车系统由于吊钩质量的存在而呈现二级摆特性。利用拉格朗日力学原理建立了二级摆型吊车系统的动态模型,分析了系统具有的特性如无源性和固有频率,提出了一种基于无源的控制方法并证明了系统的稳定性。仿真结果验证了二级摆型吊车系统的复杂性和提出控制方案的有效性,并分析了系统参数对系统性能的影响。

关键词：二级摆型吊车系统仿真无源控制稳定性

Acute and chronic excitotoxicity in ischemic stroke and late-onset Alzheimer's disease

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2025年第7期20卷 1981-1988页

作者： Shan ping Yu Emily Choi Michael QJiang Ling wei Department of Anesthesiology Emory University School of MedicineAtlantaGAUSA Center for Visual and Neurocognitive Rehabilitation Atlanta Veterans Affairs Medical CenterDecaturGAUSA

Stroke and Alzheimer's disease are common neurological disorders and often occur in the same *** comorbidity of the two neurological disorders represents a grave health threat to older *** review presents a brief background of the development of novel concepts and their clinical *** activity of glutamatergic N-methyl-D-aspartate receptors and N-methyl-D-aspartate receptor-mediated Ca^(2+)influx is critical for neuronal *** ischemic insult induces prompt and excessive glutamate release and drastic increases of intracellular Ca^(2+)mainly via N-methyl-D-aspartate receptors,particularly of those at the extrasynaptic *** Ca^(2+)-evoked neuronal cell death in the ischemic core is dominated by necrosis within a few hours and days known as acute ***,mild but sustained Ca^(2+)increases under neurodegenerative conditions such as in the distant penumbra of the ischemic brain and early stages of Alzheimer's disease are not immediately toxic,but gradually set off deteriorating Ca^(2+)-dependent signals and neuronal cell loss mostly because of activation of programmed cell death *** on the Ca^(2+)hypothesis of Alzheimer's disease and recent advances,this Ca^(2+)-activated“silent”degenerative excitotoxicity evolves from years to decades and is recognized as a unique slow and chronic *** N-methyl-D-aspartate receptor subunit GluN3A,primarily at the extrasynaptic site,serves as a gatekeeper for the N-methyl-D-aspartate receptor activity and is neuroprotective against both acute and chronic *** stroke and Alzheimer's disease,therefore,share an N-methyl-D-aspartate receptor-and Ca^(2+)-mediated mechanism,although with much different time *** is thus proposed that early interventions to control Ca^(2+)homeostasis at the preclinical stage are pivotal for individuals who are susceptible to sporadic late-onset Alzheimer's disease and Alzheimer's disease-related

关键词： Ca^(2+)hypothesis cognitive deficits hyperactivity late-onset Alzheimer's disease neurodegeneration N-methyl-D-aspartate receptors N-methyl-D-aspartate receptor subunits pathogenesis preventive treatment

Effects of Bifidobacterium lactis BLa80 on fecal and mucosal flora and stem cell factor/c-kit signaling pathway in simulated microgravity rats

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2025年第1期31卷 93-109页

作者： ping Zhang Ying Zhu Pu Chen tong Zhou Zhe-Yi Han Jun Xiao Jian-Feng Ma Wen Ma Peng Zang Ying Chen Graduate School Hebei North UniversityZhangjiakou 075000Hebei ProvinceChina Key Laboratory of Aerospace Nutrition and Food Engineering China Astronaut Research and Training CenterBeijing 100094China Department of Gastroenterology The Air Force Medical CenterBeijing 100142China Department of Blood Transfusion Air Force Medical CenterBeijing 100142China

BACKGROUND Simulated microgravity environment can lead to gastrointestinal motility *** pathogenesis of gastrointestinal motility disorders is closely related to the stem cell factor(SCF)/c-kit signaling pathway associated with intestinal flora and Cajal stromal ***,intestinal flora can also affect the regulation of SCF/c-kit signaling pathway,thus affecting the expression of Cajal stromal *** cells are the pacemakers of gastrointestinal *** To investigate the effects of Bifidobacterium lactis(***)BLa80 on the intestinal flora of rats in simulated microgravity and on the gastrointestinal motility-related SCF/c-kit *** The internationally recognized tail suspension animal model was used to simulate the microgravity environment,and 30 rats were randomly divided into control group,tail suspension group and drug administration tail suspension group with 10 rats in each group for a total of 28 *** tail group was given *** BLa80 by intragastric administration,and the other two groups were given water intragastric administration,the concentration of intragastric administration was 0.1 g/mL,and each rat was 1 mL/***&eosin staining was used to observe the histopathological changes in each segment of the intestine of each group,and the expression levels of SCF,c-kit,extracellular signal-regulated kinase(ERK)and p-ERK in the gastric antrum of each group were detected by Western blotting and *** fecal flora and mucosal flora of rats in each group were detected by 16S *** Simulated microgravity resulted in severe exfoliation of villi of duodenum,jejunum and ileum in rats,marked damage,increased space between villi,loose arrangement,shortened columnar epithelium of colon,less folds,narrower mucosal thickness,reduced goblet cell number and crypts,and significant improvement after probiotic *** microgravity reduced the expressions of SCF and c-kit,and increased the express

关键词： Simulated microgravity Rat Intestinal flora Gastrointestinal motility Stem cell factor/c-kit signaling pathway

Gut microbiota-astrocyte axis: new insights into age-related cognitive decline

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

Neural Regeneration Research 2025年第4期20卷 990-1008页

作者： Lan Zhang Jingge wei Xilei Liu Dai Li Xiaoqi Pang Fanglian Chen Hailong Cao ping Lei Haihe Laboratory of Cell Ecosystem Department of GeriatricsTianjin Medical University General HospitalTianjinChina Tianjin Geriatrics Institute Tianjin Medical University General HospitalTianjinChina Department of Gastroenterology and Hepatology Tianjin Medical University General HospitalNational Key Clinical SpecialtyTianjin Institute of Digestive DiseasesTianjin Key Laboratory of Digestive DiseasesTianjinChina Department of Urology Tianjin Medical University General HospitalTianjinChina Tianjin Neurological Institution Tianjin Medical University General HospitalTianjinChina

With the rapidly aging human population,age-related cognitive decline and dementia are becoming increasingly prevalent *** is considered the main risk factor for cognitive decline and acts through alterations in the composition of the gut microbiota,microbial metabolites,and the functions of *** microbiota–gut–brain axis has been the focus of multiple studies and is closely associated with cognitive *** article provides a comprehensive review of the specific changes that occur in the composition of the gut microbiota and microbial metabolites in older individuals and discusses how the aging of astrocytes and reactive astrocytosis are closely related to age-related cognitive decline and neurodegenerative *** article also summarizes the gut microbiota components that affect astrocyte function,mainly through the vagus nerve,immune responses,circadian rhythms,and microbial ***,this article summarizes the mechanism by which the gut microbiota–astrocyte axis plays a role in Alzheimer’s and Parkinson’s *** findings have revealed the critical role of the microbiota–astrocyte axis in age-related cognitive decline,aiding in a deeper understanding of potential gut microbiome-based adjuvant therapy strategies for this condition.

关键词： age aging Alzheimer’s disease astrocytes cognitive decline dementia gut microbiota gut–brain axis microbial metabolites neuroinflammation Parkinson’s disease

深层碳酸盐岩关键构造-流体演变与成岩-成储——以塔中奥陶系鹰山组为例

在线全文

学校读者我要写书评

暂无评论

矿物岩石地球化学通报 2016年第5期35卷 827-838页

作者：李忠李佳蔚张平童于靖波刘嘉庆杨柳中国科学院地质与地球物理研究所北京100029 中国科学院大学北京100049 中国石油杭州地质研究院杭州310023

解析系统的构造-流体体制是认识叠合盆地深层碳酸盐岩成岩-成储规律的新思路。针对塔里木盆地塔中下-中奥陶统鹰山组深层碳酸盐岩(深度、温度分别达6500m和220℃)的系统研究表明,其发育6期方解石胶结作用,准同生、表生期胶结及浅埋藏... 详细信息

解析系统的构造-流体体制是认识叠合盆地深层碳酸盐岩成岩-成储规律的新思路。针对塔里木盆地塔中下-中奥陶统鹰山组深层碳酸盐岩(深度、温度分别达6500m和220℃)的系统研究表明,其发育6期方解石胶结作用,准同生、表生期胶结及浅埋藏等前三期胶结总体显示与正常海水相关的成岩特征,相比之下中-深埋藏等后两期胶结具有明显的δ13C负值和有机碳输入特征,而热流体胶结物的δ18O、δ13C值均显示相对最大负值。除准同生期选择性溶蚀和表生期溶蚀外,塔中鹰山组主要存在两期埋藏溶蚀,其中第二期除溶蚀早期方解石胶结外,还主要溶蚀白云石,且普遍与烃类注入匹配。研究区关键时期,即中晚奥陶世北西向逆冲断裂、志留-泥盆纪北东向转换走滑断裂、二叠纪张裂及相关流体活动,分别影响了鹰山组碳酸盐岩的岩溶、埋藏溶蚀-胶结等成岩-成储过程。

关键词：构造-流体体制成岩-成储深层碳酸盐岩奥陶系鹰山组塔里木盆地

Effects of ultrasonic-assisted extraction on bioactive compounds,volatile flavors and antioxidant activities of vine tea water extracts

在线全文

学校读者我要写书评

暂无评论

Traditional Medicine Research 2025年第1期10卷 73-81页

作者： Xiao-Long Zhou wei-Jin Jiang Ji Yu Mao-Jun Yao Yun-tong Li Hunan Provincial Key Laboratory of Research Resource Mining and High-valued Utilization on Edible&Medicinal PlantCollege of Chemistry and Chemical EngineeringJishou UniversityJishou 416000China Hunan Gaoge Dairy Co. Ltd.Changsha 410000China

Background:Ampelopsis grossedentata,vine tea,which is the tea alternative beverages in *** vine tea processing,a large amount of broken tea is produced,which has low commercial ***:This study investigates the influence of different extraction methods(room temperature water extraction,boiling water extraction,ultrasonic-assisted room temperature water extraction,and ultrasonic-assisted boiling water extraction,referred to as room temperature water extraction(RE),boiling water extraction(BE),ultrasonic assistance at room temperature water extraction(URE),and ultrasonic assistance in boiling water extraction(UBE))on the yield,dihydromyricetin(DMY)content,free amino acid composition,volatile aroma components,and antioxidant properties of vine tea ***:A notable influence of extraction temperature on the yield of vine tea extracts(P<0.05),with BE yielding the highest at 43.13±0.26%,higher than that of RE(34.29±0.81%).Ultrasound-assisted extraction significantly increased the DMY content of the extracts(P<0.05),whereas DMY content in the RE extracts was 59.94±1.70%,that of URE reached 66.14±2.78%.Analysis revealed 17 amino acids,with L-serine and aspartic acid being the most abundant in the extracts,nevertheless ultrasound-assisted extraction reduced total free amino acid *** chromatography-mass spectrometry analysis demonstrated an increase in the diversity and quantity of compounds in the vine tea water extracts obtained through ultrasonic-assisted ***,69 and 68 volatile compounds were found in URE and UBE extracts,which were higher than the number found in RE and BE *** vitro,antioxidant activity assessments revealed varying antioxidant capacities among different extraction methods,with RE exhibiting the highest DPPH scavenging rate,URE leading in ABTS•+free radical scavenging,and BE demonstrating superior ferric ion reducing antioxidant ***:The findings suggest that extraction methods signi

关键词： vine tea dihydromyricetin ultrasonic-assisted extraction volatile aroma components

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

北豆根饮片HPLC指纹图谱研究

齐鲁药事 2005年第1期24卷 23-25页

作者：于维萍梁彤山东中医药大学附属医院济南250011

目的　采用高效液相色谱法建立北豆根饮片的指纹图谱。方法　以北豆根饮片为分析对象,用 phenomenexC18(4 6mm× 15 0mm,5 μm)色谱柱,采用乙腈和 0 2 %磷酸水溶液线形梯度洗脱,流速 1ml·min-1,检测波长为 2 84nm,建立了 10批北豆根... 详细信息

目的　采用高效液相色谱法建立北豆根饮片的指纹图谱。方法　以北豆根饮片为分析对象,用 phenomenexC18(4 6mm× 15 0mm,5 μm)色谱柱,采用乙腈和 0 2 %磷酸水溶液线形梯度洗脱,流速 1ml·min-1,检测波长为 2 84nm,建立了 10批北豆根饮片样品的指纹图谱。结果　北豆根饮片指纹图谱共检出 33个共有峰,其精密度、稳定性、重复性均符合中药注射剂指纹图谱研究的技术要求(暂行) 中的有关规定。结论　HPLC指纹图谱分析法可简便快速地用于北豆根饮片的质量评价。

关键词：北豆根指纹图谱高效液相色谱法