检索结果-南通市图书馆

Highly active copper-intercalated weakly crystallizedδ-MnO2 for low-temperature oxidation of CO in dry and humid air

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Environmental Science & Engineering 2024年第5期18卷 127-136页

作者： Hao Zhang Huinan Li Pengyi Zhang Tingxia Hu xianjie Wang State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing100084China Beijing Key Laboratory for Indoor Air Quality Evaluation and Control Beijing100084China Midea Corporate Research Center Foshan528311China

Copper intercalated birnessite MnO2(δ-MnO2)with weak crystallinity and high specific surface area(421 m2/g)was synthesized by a one-pot redox method and investigated for low-temperature CO oxidation.The molar ratio of Cu/Mn was as high as 0.37,which greatly weakened the Mn-O bond and created a lot of low-temperature active oxygen species.In situ DRIFTS revealed strong bonding of copper ions with CO.As-synthesized MnO2-150Cu achieved 100%conversion of 250 ppm CO in normal air(3.1 ppm H2O)even at−10°C under the weight-hourly space velocity(WHSV)of 150 L/(g·h).In addition,it showed high oxygen storage capacity to oxidize CO in inert atmosphere.Though the concurrent moisture in air significantly inhibited CO adsorption and its conversion at ambient temperature,MnO2-150Cu could stably convert CO in 1.3%moisture air at 70°C owing to its great low-temperature activity and reduced competitive adsorption of water with increased temperature.This study discovers the excellent low-temperature activity of weakly crystallizedδ-MnO2 induced by high content intercalated copper ions.

关键词： CO oxidation Birnessite Interlayer copper Low-temperature Oxygen storage capacity

Monitoring absolute vertical land motions and absolute sea-level changes from GPS and tide gauges data over French Polynesia

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Geodesy and Geodynamics 2024年第1期15卷 13-26页

作者： xianjie Li Jean-Pierre Barriot Bernard Ducarme Marania Hopuare Yidong Lou Geodesy Observatory of Tahiti University of French PolynesiaFaa'a 98702French Polynesia Catholic University of Louvain Georges Lemaître Centre for Earth and Climate Research(ELI)1348 Louvain-la-NeuveBelgium GNSS Research Center Wuhan UniversityWuhan 430079China State Key Laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan UniversityWuhan 430079China

In this study,we estimate the absolute vertical land motions at three tidal stations with collocated Global Navigation Satellite System(GNSS)receivers over French Polynesia during the period 2007-2020,and obtain,as ancillary results,estimates of the absolute changes in sea level at the same locations.To verify our processing approach to determining vertical motion,we first modeled vertical motion at the International GNSS Service(IGS)THTI station located in the capital island of Tahiti and compared our estimate with previous independent determinations,with a good agreement.We obtained the following estimates for the vertical land motions at the tide gauges:Tubuai island,Austral Archipelago-0.92±0.17 mm/yr,Vairao village,Tahiti Iti:-0.49±0.39 mm/yr,Rikitea,Gambier Archipelago-0.43±0.17 mm/yr.The absolute variations of the sea level are:Tubuai island,Austral Archipelago 5.25±0.60 mm/yr,Vairao village,Tahiti Iti:3.62±0.52 mm/yr,Rikitea,Gambier Archipelago 1.52±0.23 mm/yr.We discuss these absolute values in light of the values obtained from altimetric measurements and other means in French Polynesia.

关键词： GPS Tide gauges Sea level changes Vertical land motion

Novel phenanthrene/bibenzyl trimers from the tubers of Bletilla striata attenuate neuroinﬂammation via inhibition of NF-κB signaling pathway

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Natural Medicines 2024年第5期22卷 441-454页

作者： SHAO Siyuan SUN Mohan MA xianjie JIANG Jianwei TIAN Jinying ZHANG Jianjun YE Fei LI Shuai State Key Laboratory of Bioactive Substance and Function of Natural Medicines Institute of Materia MedicaChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 100050China

Five novel(9,10-dihydro)phenanthrene and bibenzyl trimers,as well as two previously identified biphenanthrenes and bibenzyls,were isolated from the tubers of Bletilla striata.Their structures were elucidated through comprehensive analyses of NMR and HRESIMS spectroscopic data.The absolute configurations of these compounds were determined by calculating rotational energy barriers and comparison of experimental and calculated ECD curves.Compounds 5b and 6 exhibited inhibitory effects on LPS-induced NO production in BV-2 cells,with IC_(50) values of 12.59±0.40 and 15.59±0.83μmol·L^(-1),respectively.A mechanistic study suggested that these compounds may attenuate neuroinflammation by reducing the activation of the AKT/IκB/NF-κB signaling pathway.Additionally,compounds 3a,6,and 7 demonstrated significant PTP1B inhibitory activities,with IC_(50) values of 1.52±0.34,1.39±0.11,and 1.78±0.01μmol·L^(-1),respectively.Further investigation revealed that compound 3a might inhibit LPS-induced PTP1B overexpression and NF-κB activation,thereby mitigating the neuroinflammatory response in BV-2 cells.

关键词： Bletilla striata Phenanthrene/bibenzyl trimer NO inhibition AKT/IκB/NF-κB signaling pathway PTP1B inhibitory effect

中草药对奶牛乳房炎致病菌的体外抑菌效果试验

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

中国乳业 2022年第9期 44-47页

作者：何显杰清丰县农业农村局河南清丰457300

[目的]为研究中草药对奶牛乳房炎主要致病菌体外抑菌效果。[方法]试验选取金银花等10味中草药,采用试管二倍稀释法测定其对金黄色葡萄球菌、大肠杆菌和无乳链球菌的最低抑菌浓度(MIC)。[结果]中草药对主要致病菌有不同程度的抑菌效果。... 详细信息

[目的]为研究中草药对奶牛乳房炎主要致病菌体外抑菌效果。[方法]试验选取金银花等10味中草药,采用试管二倍稀释法测定其对金黄色葡萄球菌、大肠杆菌和无乳链球菌的最低抑菌浓度(MIC)。[结果]中草药对主要致病菌有不同程度的抑菌效果。连翘对金黄色葡萄球菌的抑菌效果最好,MIC为15.63 mg/mL;板蓝根、蒲公英和黄芩对大肠杆菌抑菌效果最好,MIC为62.5 mg/mL;紫花丁对无乳链球菌抑菌效果最好,MIC为15.63 mg/mL。[结论]试验为临床研制乳房炎中草药制剂提供了技术参考。

关键词：中草药奶牛乳房炎致病菌抑菌试验

在线全文

学校读者我要写书评

暂无评论

温度场下功能梯度圆锥壳-环板振动特性分析

哈尔滨工程大学学报 2024年第4期45卷 709-716页

作者：左朋石先杰中国工程物理研究院总体工程研究所四川绵阳621999 中国科学技术大学近代力学系安徽合肥230026

针对功能梯度圆锥壳-环板组合结构振动问题,本文采用一阶剪切变形理论和Rayleigh-Ritz法分析了温度场下组合结构的振动特性。组合结构位移变量采用谱几何法来表征,考虑材料参数与温度相关并引入人工边界弹簧建立了组合结构振动特性分析... 详细信息

针对功能梯度圆锥壳-环板组合结构振动问题,本文采用一阶剪切变形理论和Rayleigh-Ritz法分析了温度场下组合结构的振动特性。组合结构位移变量采用谱几何法来表征,考虑材料参数与温度相关并引入人工边界弹簧建立了组合结构振动特性分析模型。数值算例中,通过将文中求解结果与文献解和有限元法结果进行对比验证了模型的正确性,进而分析尺寸、材料、温度和连接位置等参数对结构振动特性的影响。研究结果表明:组合结构基频随厚度增加而增加,随着幂律指数、半顶角和温度场参数增加而降低,随环板内径和连接位置变化会呈现非单一变化趋势。

关键词：谱几何法温度场功能梯度结构圆锥壳-环板组合结构自由振动一阶剪切变形理论边界弹簧结构基频

维普期刊数据库博看期刊

在线全文

学校读者我要写书评

暂无评论

数显浮球液位仪研制与钻井溢漏预警试验

钻采工艺 2022年第6期45卷 107-112页

作者：何弦桀晏琰杨晓明中国石油川庆钻探工程有限公司钻采工程技术研究院四川省广汉市618300 中国石油川庆钻探工程有限公司页岩气勘探开发项目经理部中国石油川庆钻探工程有限公司川东钻探公司

目前,钻井现场主要采用超声波液位计和浮球式液位仪对循环罐钻井液液位进行监测,虽然超声波液位计实现了实时、连续测量,但当液面波动较大时其监测效果受到一定影响,容易产生误报。浮球式液位仪的监测更加稳定、可信度高,是井队判断循... 详细信息

目前,钻井现场主要采用超声波液位计和浮球式液位仪对循环罐钻井液液位进行监测,虽然超声波液位计实现了实时、连续测量,但当液面波动较大时其监测效果受到一定影响,容易产生误报。浮球式液位仪的监测更加稳定、可信度高,是井队判断循环罐液位的主要手段;但现有装置不能多点、实时记录循环罐钻井液液位的变化,需要坐岗人员定时观察记录,人员劳动强度大,溢漏判断准确度低、及时性差。此外,现有技术无法自动准确识别泥浆工加料、启停泵操作等,使用过程中误报率较高。针对上述问题,研发了一种基于循环罐浮球液位仪的数字显示与溢漏预警系统。现场应用表明该系统能够在开泵、停泵、变排量等环节均实时、连续、稳定监测循环罐液面波动,精度达到±1 mm,并成功预警1次井漏事件。系统实现了循环罐钻井液液位监测的数字显示,对于提高溢漏识别的准确度、减少误报和漏报,进一步保证钻井安全具有重要意义。

关键词：循环罐液位浮球数字显示实时监测连续监测溢漏预警

在线全文

学校读者我要写书评

暂无评论

井喷失控井一体化井口重建装置的研制

钻采工艺 2022年第2期45卷 94-99页

作者：胡旭光何弦桀段慕白中国石油川庆钻探工程有限公司井控应急救援响应中心四川省广汉市618300 西南石油大学石油与天然气工程学院中国石油川庆钻探工程有限公司钻采工程技术研究院

井喷失控是油气勘探开发过程中损失巨大的灾难性事故,必须快速恢复对井口的重新控制,而拆除旧井口后的新井口重建是最为关键、风险最高的一步。传统的井口重建装备需要人员多次近井口作业完成新井口安装,抢险人员面临巨大的安全风险且... 详细信息

井喷失控是油气勘探开发过程中损失巨大的灾难性事故,必须快速恢复对井口的重新控制,而拆除旧井口后的新井口重建是最为关键、风险最高的一步。传统的井口重建装备需要人员多次近井口作业完成新井口安装,抢险人员面临巨大的安全风险且一次性成功率较低,需多次尝试。针对此种情况,研制了井喷失控井一体化井口重建装置,将原有井口重建工艺“八步法”变为“一步法”,避免抢险人员多次近井口作业。文章详细阐述了该装置的组合方式、卡紧设计及密封设计,通过有限元模拟对装置的力学性能进行校核。室内实验及应急演练表明,该装置能快速实现光套管下井喷失控井口的重建,极大简化了新井口重建流程,提高了重建效率及人员安全性,对推进井喷失控近井口作业无人化进程提供了更加完善的装备支撑。

关键词：井喷失控井口重建一体化井口重建装置重建流程无人化

Strict constraints on 2D primitive pairs for engineering symbol recognition:Theory and application

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2012年第5期55卷 1032-1041页

作者： LI Ting 1,2,QIU xianjie 1,HUANG he 1 & WANG ZhaoQi 1 1 Virtual Reality Laboratory,Institute of Computing Technology Chinese Academy of Sciences,Beijing 100190,China 2 Graduate University of Chinese Academy of Sciences,Beijing 100049,China Virtual Reality Laboratory Institute of Computing Technology Chinese Academy of Sciences Beijing China Graduate University of Chinese Academy of Sciences Beijing China

Geometric constraints on the line-line pair,line-arc pair and arcarc pair are proposed.The con-straints are able to encode the geometric relations between lines,arcs and circles.A geometric proof is presented to demonstrate that the constraints are stable under translation,rotation,uniform scaling or reflection of the primitive pairs.Based on the constraints,an algorithm for recognizing symbols in drawings is developed.Ex-perimental results show that,compared with three other methods,our method can distinguish more primitive pairs and has higher accuracy in engineering symbol recognition.

关键词： coordinated multi-point transmission multicell cooperation capacity analysis MIMO-OFDM power allocation frequency selective MIMO channel

Cellular metabolism: A key player in cancer ferroptosis

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Cancer Communications 2024年第2期44卷 185-204页

作者： xianjie Jiang Qiu Peng Mingjing Peng Linda Oyang Honghan Wang Qiang Liu Xuemeng Xu Nayiyuan Wu Shiming Tan Wenjuan Yang Yaqian Han Jinguan Lin Longzheng Xia Yanyan Tang Xia Luo Jie Dai Yujuan Zhou Qianjin Liao Hunan Key Laboratory of Cancer Metabolism Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of MedicineCentral South UniversityChangshaHunanP.R.China Public Service Platform of Tumor Organoids Technology ChangshaHunanP.R.China Department of head and Neck Surgery Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of MedicineCentral South UniversityChangshaHunanP.R.China hengyang Medical School University of South ChinaHengyangHunanP.R.China

Cellular metabolism is the fundamental process by which cells maintain growth and self-renewal.It produces energy,furnishes raw materials,and intermedi-ates for biomolecule synthesis,and modulates enzyme activity to sustain normal cellular functions.Cellular metabolism is the foundation of cellular life processes and plays a regulatory role in various biological functions,including pro-grammed cell death.Ferroptosis is a recently discovered form of iron-dependent programmed cell death.The inhibition of ferroptosis plays a crucial role in tumorigenesis and tumor progression.However,the role of cellular metabolism,particularly glucose and amino acid metabolism,in cancer ferroptosis is not well understood.here,we reviewed glucose,lipid,amino acid,iron and sele-nium metabolism involvement in cancer cell ferroptosis to elucidate the impact of different metabolic pathways on this process.Additionally,we provided a detailed overview of agents used to induce cancer ferroptosis.We explained that the metabolism of tumor cells plays a crucial role in maintaining intracellu-lar redox homeostasis and that disrupting the normal metabolic processes in these cells renders them more susceptible to iron-induced cell death,resulting in enhanced tumor cell killing.The combination of ferroptosis inducers and cel-lular metabolism inhibitors may be a novel approach to future cancer therapy and an important strategy to advance the development of treatments.

关键词： cancer therapy cellular metabolism ferroptosis inducer ferroptosis