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In Situ TiC/FeCrNiCu High-Entropy Alloy Matrix Composites:Reaction Mechanism,Microstructure and Mechanical Properties 认领
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作者 Hao Wu Si-Rui Huang +3 位作者 Cheng-Yan Zhu Ji-Feng Zhang He-Guo Zhu Zong-Han Xie 《金属学报:英文版》 SCIE EI CAS CSCD 2020年第8期1091-1102,共12页
In situ TiC particles-reinforced FeCrNiCu high-entropy alloy matrix composites were prepared by vacuum induction melting method.The reaction mechanisms of the mixed powder(Ti,Cu and C)were analyzed,and the mechanical ... In situ TiC particles-reinforced FeCrNiCu high-entropy alloy matrix composites were prepared by vacuum induction melting method.The reaction mechanisms of the mixed powder(Ti,Cu and C)were analyzed,and the mechanical properties of resultant composites were determined.Cu4Tiwere formed in the reaction of Cu and Ti when the temperature rose to 1160 K.With the temperature further increased to 1182 K,newly formed Cu4Tireacted with C to give rise to TiC particles as reinforcement agents.The apparent activation energy for these two reactions was calculated to be 578.7 kJ/mol and 1443.2 kJ/mol,respectively.The hardness,tensile yield strength and ultimate tensile strength of the 15 vol%TiC/FeCrNiCu composite are 797.3 HV,605.1 MPa and 769.2 MPa,respectively,representing an increase by 126.9%,65.9%and 36.0%as compared to the FeCrNiCu high-entropy base alloy at room temperature.However,the elongation-to-failure is reduced from 21.5 to 6.1%with the formation of TiC particles.It was revealed that Orowan mechanism,dislocation strengthening and load-bearing effect are key factors responsible for a marked increase in the hardness and strength of the high-entropy alloy matrix composites. 展开更多
关键词 High-entropy alloy matrix composite TiC particle Reaction mechanism Mechanical properties Strengthening mechanism
Design and analysis of a class of redundant collaborative manipulators with 2D large rotational angles 认领
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作者 Xiaodong JIN Yuefa FANG +1 位作者 Dan ZHANG Xueling LUO 《机械工程前沿:英文版》 SCIE CSCD 2020年第1期66-80,共15页
The parallel spindle heads with high rotational capability are demanded in the area of multi-axis machine tools and 3D printers.This paper focuses on designing a class of 2R1T(R:Rotation;T:Translation)parallel spindle... The parallel spindle heads with high rotational capability are demanded in the area of multi-axis machine tools and 3D printers.This paper focuses on designing a class of 2R1T(R:Rotation;T:Translation)parallel spindle heads and the corresponding collaborative 5-axis manipulators with 2-dimension(2D)large rotational angles.In order to construct 2D rotational degrees of freedom(DOFs),a platform with 2D revolute joints is proposed first.Based on the constraint screw theory,the feasible limbs that can be connected in the platform are synthesized.In order to provide constant rotational axis for the platform,a class of redundant limbs are designed.A class of redundant 2R1T parallel spindle heads is obtained by connecting the redundant limbs with the platform and the redundant characteristics are verified by the modified Grübler-Kutzbach criterion.The corresponding 5-axis collaborative manipulators are presented by constructing a 2-DOF series translational bottom moving platform.The inverse kinematics and the orientation workspace as well as the decoupling characteristics of this type of 2R1T parallel spindle heads are analyzed.The results show that these manipulators have large 2D rotational angles than the traditional A3/Z3 heads and can be potentially used in the application of multi-axis machine tools and the 3D printers. 展开更多
关键词 parallel MECHANISM REDUNDANT MECHANISM LARGE rotational ANGLES machine tools 2R1T spindle head COLLABORATIVE manipulator
技术创新与工业绿色化:作用机理和实证检验 认领
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作者 韩立达 史敦友 张卫 《经济问题探索》 CSSCI 北大核心 2020年第5期176-190,共15页
技术创新是工业绿色化的重要动力,研究技术创新对工业绿色化的影响,对推进中国工业绿色化具有重要的理论意义和实践价值。本文将技术创新对工业绿色化影响的作用机理归纳为直接作用机理、市场传导机制和路径依赖三大部分,基于2007-2016... 技术创新是工业绿色化的重要动力,研究技术创新对工业绿色化的影响,对推进中国工业绿色化具有重要的理论意义和实践价值。本文将技术创新对工业绿色化影响的作用机理归纳为直接作用机理、市场传导机制和路径依赖三大部分,基于2007-2016年中国省际面板数据和系统GMM方法,将技术创新对工业绿色化影响的作用机理进行实证检验。研究结果显示:①技术创新有利于工业绿色化;技术创新还通过技术溢出效应促进邻近地区工业绿色化,但人力资本溢出效应则相反;市场开放形成的国际市场潜力促进工业绿色化,但国内市场潜力与之相反;上一期工业绿色化积累有利于本期工业绿色化。②技术溢出效应与国内外市场潜力联动及人力资本溢出效应与国内外市场潜力联动均有利于工业绿色化,但国内外市场潜力联动对工业绿色化起抑制作用。③技术溢出效应和人力资本溢出效应与国内外市场潜力联动对工业绿色化影响及国内外市场潜力联动对工业绿色化影响都存在明显的区域异质性。④以技术研发创新投入和人力资本水平因子分别替代发明专利因子并作为技术研发创新的测度指标,实证结果仍具有一定稳健性。因此,为推进中国工业绿色化,一是全面提升技术创新能力,加大技术创新政策支持力度,鼓励企业实施清洁型技术创新;二是推进区域经济一体化建设,降低制度对人力资本市场流动束缚,消除创新外溢与市场联动对工业绿色化影响的区域异质性;三是统筹内外市场联动发展,释放创新外溢与市场联动对工业绿色化的促进作用,并抑制国内外市场联动对工业绿色化的不利格局。 展开更多
关键词 技术创新 工业绿色化 作用机理 路径依赖 市场传导机制
Application of nanoparticles in cast steel:An overview 认领
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作者 Feng Qiu Tian-shu Liu +5 位作者 Xin Zhang Fang Chang Shi-li Shu Hong-yu Yang Qing-long Zhao Qi-chuan Jiang 《中国铸造:英文版》 SCIE 2020年第2期111-126,共16页
The innovative and environmentally friendly methodologies for comprehensively enhancing the performances of high-strength steels without damage to plasticity,toughness and heat/corrosion/fatigue resistance are being d... The innovative and environmentally friendly methodologies for comprehensively enhancing the performances of high-strength steels without damage to plasticity,toughness and heat/corrosion/fatigue resistance are being developed.In recent years,nanoparticles elevate the field of high-strength steel.It is proposed that nanoparticles have the potential to replace conventional semi-coherent intermetallic compounds,carbides and alloying to optimize the steel.The fabrication process is simplified and the cost is lower compared with the traditional methods.Considerable research effort has been directed towards high-performance cast steels reinforced with nanoparticles due to potential application in major engineering.Nanoparticles are found to be capable of notably optimizing the nucleation behavior and precipitate process.The prominently optimized microstructure configuration and performances of cast steel can be acquired synchronously.In this review,the lattice matching and valence electron criterion between diverse nanoparticles and steel are summarized,and the existing various preparation methods are compared and analyzed.At present,there are four main methods to introduce nanoparticles into steel:external nanoparticle method,internal nanoparticle method,in-situ reaction method,and additive manufacturing method.These four methods have their own advantages and limitations,respectively.In this review,the synthesis,selection principle and strengthening mechanism of nanoparticles in cast steels for the above four methods are discussed in detail.Moreover,the main preparation methods and microstructure manipulation mechanism of the steel reinforced with different nanoparticles have been systematically expatiated.Finally,the development and future potential research directions of the application of nanoparticles in cast steel are prospected. 展开更多
关键词 NANOPARTICLES HIGH-PERFORMANCE steel strengthening MECHANISM preparation method microstructure MANIPULATION MECHANISM
Novel method of constructing generalized Hoberman sphere mechanisms based on deployment axes 认领
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作者 Xuemin SUN Yan-An YAO Ruiming LI 《机械工程前沿:英文版》 SCIE CSCD 2020年第1期89-99,共11页
This study proposes a method of constructing type Ⅱ generalized angulated elements(GAEs Ⅱ)Hoberman sphere mechanisms on the basis of deployment axes that intersect at one point.First,the constraint conditions for in... This study proposes a method of constructing type Ⅱ generalized angulated elements(GAEs Ⅱ)Hoberman sphere mechanisms on the basis of deployment axes that intersect at one point.First,the constraint conditions for inserting n GAEs II into n deployment axes to form a loop are given.The angle constraint conditions of the deployment axes are obtained through a series of linear equations.Second,the connection conditions of two GAEs Ⅱ loops that share a common deployable center are discussed.Third,a flowchart of constructing the generalized Hoberman sphere mechanism on the basis of deployment axes is provided.Finally,four generalized Hoberman sphere mechanisms based on a fully enclosed regular hexahedron,arithmetic sequence axes,orthonormal arithmetic sequence axes,and spiral-like axes are constructed in accordance with the given arrangement of deployment axes that satisfy the constraint conditions to verify the feasibility of the proposed method. 展开更多
关键词 DEPLOYABLE MECHANISM typeⅡgeneralized angulated elements Hoberman SPHERE MECHANISM DEPLOYMENT axes constraint conditions
Nervous mechanisms of restraint water-immersion stress-induced gastric mucosal lesion 认领
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作者 Dong-Qin Zhao Hua Xue Hai-Ji Sun 《世界胃肠病学杂志:英文版》 SCIE CAS 2020年第20期2533-2549,共17页
Stress-induced gastric mucosal lesion(SGML)is one of the most common visceral complications after trauma.Exploring the nervous mechanisms of SGML has become a research hotspot.Restraint water-immersion stress(RWIS)can... Stress-induced gastric mucosal lesion(SGML)is one of the most common visceral complications after trauma.Exploring the nervous mechanisms of SGML has become a research hotspot.Restraint water-immersion stress(RWIS)can induce GML and has been widely used to elucidate the nervous mechanisms of SGML.It is believed that RWIS-induced GML is mainly caused by the enhanced activity of vagal parasympathetic nerves.Many central nuclei,such as the dorsal motor nucleus of the vagus,nucleus of the solitary tract,supraoptic nucleus and paraventricular nucleus of the hypothalamus,mediodorsal nucleus of the thalamus,central nucleus of the amygdala and medial prefrontal cortex,are involved in the formation of SGML in varying degrees.Neurotransmitters/neuromodulators,such as nitric oxide,hydrogen sulfide,vasoactive intestinal peptide,calcitonin gene-related peptide,substance P,enkephalin,5-hydroxytryptamine,acetylcholine,catecholamine,glutamate,γ-aminobutyric acid,oxytocin and arginine vasopressin,can participate in the regulation of stress.However,inconsistent and even contradictory results have been obtained regarding the actual roles of each nucleus in the nervous mechanism of RWIS-induced GML,such as the involvement of different nuclei with the time of RWIS,the different levels of involvement of the sub-regions of the same nucleus,and the diverse signalling molecules,remain to be further elucidated. 展开更多
关键词 Restraint water-immersion stress Stress-induced gastric mucosal lesion Central mechanism Peripheral mechanism
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Priori information analysis of optocoupler accelerated degradation experiment based on failure mechanism verification test 认领
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作者 Xuan-gong Zhang Xi-hui Mu +1 位作者 Jing Feng Hui-zhi Li 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2020年第2期392-400,共9页
The optocoupler is a weak link in the inertial navigation platform of a kind of guided munitions.It is necessary to use accelerated storage test to verify the storage life of long storage products.Especially for small... The optocoupler is a weak link in the inertial navigation platform of a kind of guided munitions.It is necessary to use accelerated storage test to verify the storage life of long storage products.Especially for small sample products,it is very important to obtain prior information for the design and implementation of accelerated degradation test.In this paper,the optocoupler failure mechanism verification test is designed and the experimental results are analyzed and the prior information is obtained.The results show that optocouplers have two failure modes,one is sudden failure and the other is degradation failure;the maximum temperature stress of optocoupler can’t exceed 140℃;the increase of leakage current of optocoupler is caused by movable ions contaminating the LED chip.The surface leakage current is proportional to the adsorption amount.The increase of leakage current makes p-n junction tunneling effect occur which LEDs the failure of the optocoupler.The lifetime distribution model of the optocoupler is determined by the failure physics.The lifetime of the optocoupler is subject to the lognormal distribution.The degeneracy orbit of the optocoupler leakage current is described by a power law model.The estimated values of the orbital parameters are initially calculated and the parameters of its life distribution function are deduced.The above information lays a good foundation for the optimization design and data processing of the accelerated degradation experiment. 展开更多
关键词 Priori information FAILURE MECHANISM FAILURE MECHANISM VERIFICATION TEST ACCELERATED degradation
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Two novel sets of UiO-66@metal oxide/graphene oxide Z-scheme heterojunction:Insight into tetracycline and malathion photodegradation 认领
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作者 Hanieh Fakhri Hasan Bagheri 《环境科学学报:英文版》 SCIE EI CAS CSCD 2020年第5期222-236,共15页
Nowadays,widespread researches have been focused on the development of effective photocatalysts to remove pollutants of the aquatic system.In accordance with the universal studies,two new sets of UiO-66@metal oxide(in... Nowadays,widespread researches have been focused on the development of effective photocatalysts to remove pollutants of the aquatic system.In accordance with the universal studies,two new sets of UiO-66@metal oxide(including ZnO and TiO2)/graphene oxide heterojunctions were synthesized for photodegradation of aromatic(tetracycline)and nonaromatic(malathion)pollutants which are challenging cases in the environment.The dosage of the photocatalyst,pH of the solution,the type of metal oxide,and the presence of various scavengers are assayed parameters in this work.In the optimum condition,maximum photodegradation efficiency is achieved in 90 min for tetracycline(81%)and malathion(100%)by the UiO-66@ZnO/graphene oxide.The superior separation of charge carriers by Z-scheme mechanism,excellent electron mobility on layers of graphene oxide and high surface area are factors that enhanced the efficiency.Furthermore,in comparison with pure UiO-66,the band gaps belong to heterojunctions revealed a red shift in the absorption edge,which can be responsible for more expand adsorption of the solar spectrum.Total organic carbon analysis verified the decontamination of these pollutants in the solution.The produced main intermediates during the photocatalytic process were identified and the possible degradation pathway proposed.In general,the superior photocatalytic activity suggests that these designed photocatalysts can be a promising choice for having a clean future. 展开更多
关键词 Metal-organic framework UiO-66 PHOTODEGRADATION MALATHION TETRACYCLINE Z-scheme mechanism
自然疗养因子的作用机制研究进展 认领
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作者 徐莉 张星 +3 位作者 肖振 蔡文泳 王茜 张鹏飞 《中国疗养医学》 2020年第6期569-573,共5页
自然疗养因子所涵盖的内容丰富,其生物学效应及形成复杂。现代疗养学在形成过程中相继提出自然疗养因子对机体作用的理论或假说。随着医学模式的转变和现代医学的发展,自然疗养因子作用机制研究从分子、细胞到组织器官,涉及机体物质代... 自然疗养因子所涵盖的内容丰富,其生物学效应及形成复杂。现代疗养学在形成过程中相继提出自然疗养因子对机体作用的理论或假说。随着医学模式的转变和现代医学的发展,自然疗养因子作用机制研究从分子、细胞到组织器官,涉及机体物质代谢、神经系统、内分泌和免疫等功能的相互作用,形成整体的各个水平产生适应的作用机制;研究证实自然疗养因子的作用最根本的表现为改善机体内环境稳态和机体与外环境间的平衡,是靠机体的适应性反应机制实现的;其次与祖国医学“天人合一”整体观一脉相承。近年来,研究证实环境因素通过基因的重返表达对表观遗传产生影响,同时疗养因子参与机体的生物节律调控不断深入,机体对自然疗养因子的应答反应是受到多种因素的影响,包括机体状态、疗养因子的种类、性质、作用剂量、应用时间、季节及个体差异等。本文主要对自然疗养因子的作用机制及对机体的作用等方面进行总结。 展开更多
关键词 自然疗养因子 共性 特异性 作用 机制
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Lung cancer from a focal bulla into thin-walled adenocarcinoma with ground glass opacity—an observation for more than 10 years:A case report 认领
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作者 Shu-Shi Meng Shao-Dong Wang +1 位作者 Yuan-Yuan Zhang Jun Wang 《世界临床病例杂志》 SCIE 2020年第11期2312-2317,共6页
BACKGROUND Thin-walled lung cancer manifests as a cystic lesion,mostly adenocarcinoma.It is often misdiagnosed as a benign lesion in clinical practice,thus delaying the diagnosis and surgical treatment.Its natural cou... BACKGROUND Thin-walled lung cancer manifests as a cystic lesion,mostly adenocarcinoma.It is often misdiagnosed as a benign lesion in clinical practice,thus delaying the diagnosis and surgical treatment.Its natural course is rarely recorded and observed;thus,the pathogenesis and diagnosis need to be clarified and improved.CASE SUMMARY A 66-year-old man developed a mass in the upper lobe of the right lung and a small,thin-walled cavity in the lower lobe of the right lung in 2007.The right upper lobe mass was confirmed to be adenocarcinoma after surgery.The cavity diameter increased from 11 mm to 31 mm over 10 years,and a ground glass opacity lesion appeared around the bulla on computed tomography.A second operation confirmed that the lesion was lepidic predominant adenocarcinoma.Here we report a rare case of lung cancer developing from a focal bulla to a thinwalled adenocarcinoma for more than 10 years and confirm that the check-valve mechanism explains the pathogenesis.CONCLUSION Solitary thin-walled lung adenocarcinoma is a rare tumor in terms of its clinical manifestations,pathogenesis,and disease progression.The check-valve mechanism can explain the cause of thin-walled lung cancer.Close follow-up and accurate imaging are necessary. 展开更多
关键词 Thin-walled lung cancer OBSERVATION The check-valve mechanism Case report
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放射增敏剂IPdR的作用机制及研究进展 认领
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作者 丁艺 张庆生 《中国药事》 CAS 2020年第6期687-692,共6页
目的:对放射增敏剂5-碘-2-嘧啶酮-2’脱氧核糖(IPdR)进行综述,为放射增敏剂提供研发思路及参考。方法:通过查阅国内外相关文献,分析IPdR理化性质、作用机理及其作为放射增敏剂的优势,总结IPdR的药效和毒理学研究结果以及Ⅰ期临床的最新... 目的:对放射增敏剂5-碘-2-嘧啶酮-2’脱氧核糖(IPdR)进行综述,为放射增敏剂提供研发思路及参考。方法:通过查阅国内外相关文献,分析IPdR理化性质、作用机理及其作为放射增敏剂的优势,总结IPdR的药效和毒理学研究结果以及Ⅰ期临床的最新进展,对Ⅱ期临床试验的开展及安全评估方案进行展望。结果与结论:IPdR作为IUdR(5-碘-2’去氧尿苷)的前体化合物,是一种卤代核苷类似物,可通过口服进入人体。血液中的IPdR在醛氧化酶的作用下,逐渐转化为能够发挥药效的IUdR,进而与肿瘤细胞的DNA结合,提高了病灶组织的放射敏感性,从而发挥药效。根据前期药效和毒理学数据发现,IPdR作为放射增敏剂效果良好,具有可口服、毒性较低的特点。目前该药物已经完成Ⅰ期临床,即将开展Ⅱ临床试验,有望成为一种新型的口服放射增敏药物。 展开更多
关键词 放射增敏剂 抗肿瘤 IPdR 机制 放射治疗
Phthalonitrile Resins Derived from Vanillin: Synthesis, Curing Behavior, and Thermal Properties 认领
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作者 Yue Han Dong-Hao Tang +4 位作者 Guang-Xing Wang Ya-Nan Sun Ying Guo Heng Zhou Wen-Feng Qiu 《高分子科学:英文版》 SCIE CAS CSCD 2020年第1期72-83,I0007共13页
Vanillin was used as sustainable source for phthalonitrile monomer synthesis, and allyl/propargyl ether moieties were introduced to improve the processability at the minimal cost of thermal properties. The synthesis r... Vanillin was used as sustainable source for phthalonitrile monomer synthesis, and allyl/propargyl ether moieties were introduced to improve the processability at the minimal cost of thermal properties. The synthesis route was optimized to minimize side-reactions and simplify post-processing, and the monomers were obtained in high purity and good yields. The curing behavior, mechanism, and processability of the monomers were studied, and the thermal properties of cured polymers were evaluated. Of the two monomers, the allyl ether-containing one exhibited a wide processing window of 185 °C, and was mainly cured into phthalocyanine and linear aliphatic structures through self-catalytic curing process. Also, the glass transition temperature was higher than 500 °C. In contrast, the propargyl ether-containing monomer could only be partially cured, and heat resistance was found to be compromised. Compared with traditional petroleum-based phthalonitrile resins, the biobased monomers could be cured without the addition of catalysts, and improvement in processability was achieved at no cost of thermal performances. 展开更多
关键词 ALLYL ETHER CURING mechanism PHTHALONITRILE Thermal properties VANILLIN
金属有机框架材料UTSA-74高效去除水溶液中的砷 认领
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作者 余文婷 张慧 +2 位作者 孙玉珍 吴昊 罗明标 《应用化学》 CAS CSCD 北大核心 2020年第2期205-210,共6页
利用水热法合成金属有机框架材料UTSA-74,并用它同时去除水中的As(Ⅴ)和As(Ⅲ)。批次实验结果表明,在低质量浓度情况下(~1 mg/L),UTSA-74对As(Ⅴ)的去除率高达95%。对As(Ⅲ)的去除率达85%。经拟合,本实验符合拟二级动力学及Freundlich... 利用水热法合成金属有机框架材料UTSA-74,并用它同时去除水中的As(Ⅴ)和As(Ⅲ)。批次实验结果表明,在低质量浓度情况下(~1 mg/L),UTSA-74对As(Ⅴ)的去除率高达95%。对As(Ⅲ)的去除率达85%。经拟合,本实验符合拟二级动力学及Freundlich等温吸附模型。本文还探究了共存离子(如Cl^-、NO3^-、PO4^3-)干扰影响,结果表明PO4^3-的存在会抑制吸附的进行,可能是由于竞争吸附位点所致。此外,本文对吸附后的材料进行洗脱(0.1 mol/L NaOH),将洗脱后的UTSA-74材料再次进行吸附探究,反复3次,其去除率仍可达70%左右。为探究其中机理,本文通过X射线衍射(XRD)、扫描电子显微镜(SEM)、红外光谱(IR)对吸附前后材料进行表征,结果表明吸附过程中可能形成了Zn—O—As,以此促进吸附反应的进行。综上所述,UTSA-74可以作为一种处理砷的新型吸附剂,具有一定的实用价值。 展开更多
关键词 去除 UTSA-74 机理
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Study of Mechanisms of CO and NO2O xidation on Zn–CNT(6,0) and Zn–BNNT(6,0),Mn–B38N38 and Mn–C76 认领
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作者 曾智文 李翔 +1 位作者 张复兴 NAJAFI Meysam 《结构化学》 SCIE CAS CSCD 2020年第1期41-47,2共8页
The abilities and performances of Mn–C76,Mn–B38N38,Zn–CNT(6,0)and Zn–BNNT(6,0)to the oxidation of NO2 and CO are investigated.The oxidation reactions of NO2 and CO through the Langmuir-Hinshelwood(LH)and Eley-Ride... The abilities and performances of Mn–C76,Mn–B38N38,Zn–CNT(6,0)and Zn–BNNT(6,0)to the oxidation of NO2 and CO are investigated.The oxidation reactions of NO2 and CO through the Langmuir-Hinshelwood(LH)and Eley-Rideal(ER)mechanisms by theoretical methods are examined.The most stable intermediates of oxidation reactions of NO2 and CO on Mn–C76,Mn–B38N38,Zn–CNT(6,0)and Zn–BNNT(6,0)are obtained from thermodynamics view point.In the LH pathway,Mn–C76,Mn–B38N38,Zn–CNT(6,0)and Zn–BNNT(6,0)catalysts are deactivated via the second NO2 and CO molecules.In the ER pathway,the second NO3 and CO2 molecules are separated.Finally,the Mn–C76,Mn–B38N38,Zn–CNT(6,0)and Zn–BNNT(6,0)are proposed to oxidize NO2 and CO molecules with high performances at room temperature. 展开更多
关键词 NO2 CO2 CATALYST MECHANISM NANO MN and ZN
竞技健美操腕关节损伤的机制、治疗及预防 认领
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作者 黄志欣 《体育科技文献通报》 2020年第5期49-50,共2页
腕关节是竞技健美操运动员在长期的训练和比赛中出现损伤的部位,这种损伤的治疗方法多种多样,它的治疗与预防也需要建立在对其损伤机制了解的基础上。本文通过文献资料法,梳理近年来竞技健美操项目中关于腕关节损伤的机制、治疗及预防... 腕关节是竞技健美操运动员在长期的训练和比赛中出现损伤的部位,这种损伤的治疗方法多种多样,它的治疗与预防也需要建立在对其损伤机制了解的基础上。本文通过文献资料法,梳理近年来竞技健美操项目中关于腕关节损伤的机制、治疗及预防的研究,并进行总结,给出自己的建议。 展开更多
关键词 腕关节 竞技健美操 机制 治疗 预防
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载硫活性炭脱汞性能及其反应机理研究 认领
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作者 陶君 谷小兵 +1 位作者 李娜 段钰锋 《热能动力工程》 CAS CSCD 北大核心 2020年第2期201-207,共7页
以市售商业载硫活性炭为研究对象,在固定床实验台上进行汞吸附实验,分析吸附温度、入口汞浓度对其脱汞性能的影响,通过表征方法对失活前后吸附剂的物理化学性质进行对比,采用程序升温热脱附实验得到样品中吸附的汞形态,并探究其脱汞机... 以市售商业载硫活性炭为研究对象,在固定床实验台上进行汞吸附实验,分析吸附温度、入口汞浓度对其脱汞性能的影响,通过表征方法对失活前后吸附剂的物理化学性质进行对比,采用程序升温热脱附实验得到样品中吸附的汞形态,并探究其脱汞机理。结果表明:实验样品的适宜脱汞温度为70℃,脱汞效率随着汞浓度的升高而降低;活性炭样品失活后比表面积下降,表面含氧官能团减少,非氧化态硫含量降低,其汞吸附形态以HgS、HgO为主;载硫活性炭样品对汞的吸附脱除主要依靠含氧官能团和含硫官能团的化学吸附作用。 展开更多
关键词 载硫活性炭 脱汞 吸附 失活 机理
重组人白血病抑制因子蛋白对兔椎间盘退变模型髓核细胞凋亡的影响机制 认领
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作者 穆林 房昕 +2 位作者 龚箭 高迎庆 周强 《中国医院用药评价与分析》 2020年第4期403-406,共4页
目的:探讨重组人白血病抑制因子(leukemia inhibitory factor,LIF)蛋白对兔椎间盘退变模型髓核细胞(nucleus pulposus cells,NPCs)凋亡的影响机制。方法:采用针刺法构建兔椎间盘退变模型,利用磁共振成像观察兔椎间盘退变程度,摘除髓核... 目的:探讨重组人白血病抑制因子(leukemia inhibitory factor,LIF)蛋白对兔椎间盘退变模型髓核细胞(nucleus pulposus cells,NPCs)凋亡的影响机制。方法:采用针刺法构建兔椎间盘退变模型,利用磁共振成像观察兔椎间盘退变程度,摘除髓核组织提取组织蛋白,采用Western Blot法检测髓核组织LIF蛋白表达水平,提取退变NPCs,采用流式细胞术观察不同浓度重组人LIF蛋白对退变NPCs凋亡的影响,采用Western Blot法检测不同浓度重组人LIF蛋白对细胞外基质成分和MAPK-ERK1/2通路蛋白表达的影响。结果:模型组兔的椎间盘高度和信号-噪声比(SNR)明显低于对照组,差异均有统计学意义(P<0.05);模型组兔髓核组织中LIF蛋白表达水平明显高于对照组,差异有统计学意义(P<0.05);针刺2周、4周及8周,各组兔髓核组织中LIF蛋白表达水平比较,差异有统计学意义(P<0.05);0、10、20、50及100 ng/ml重组人LIF蛋白处理的退变NPCs凋亡率比较,差异有统计学意义(P<0.05);0、10、20、50及100 ng/ml重组人LIF蛋白处理的退变NPCs中Aggtecan蛋白、Ⅱ型胶原及p-ERK1/2蛋白表达水平比较,差异有统计学意义(P<0.05)。结论:兔椎间盘退变髓核组织中LIF蛋白呈高表达,其可能通过激活ERK1/2通路促进细胞外基质合成达到抑制NPCs凋亡作用,重组LIF在延缓椎间盘退变方面显示出了良好前景。 展开更多
关键词 重组人LIF蛋白 兔椎间盘退变模型 髓核细胞凋亡 机制
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改制成功背景下成教体制机制改革的实践探索 认领
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作者 周信德 《宁波教育学院学报》 2020年第3期37-39,共3页
从成人本科学校改制为全日制普通高等专科学校,成人学历教育只能招收专科函授学生,招生形势十分严峻,也对我校成人教育的发展带来巨大的冲击。通过在甬高校继续教育学院的工作调研,同时结合市内外继续教育专家学者的访谈,在调研和查阅... 从成人本科学校改制为全日制普通高等专科学校,成人学历教育只能招收专科函授学生,招生形势十分严峻,也对我校成人教育的发展带来巨大的冲击。通过在甬高校继续教育学院的工作调研,同时结合市内外继续教育专家学者的访谈,在调研和查阅文献资料的基础上,结合多年的成人教育工作实践,积极探索我校成人学历教育的发展路径。 展开更多
关键词 改制转型 成人教育 体制 机制 改革
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Mechanism and catalytic performance for direct dimethyl ether synthesis by CO2 hydrogenation over CuZnZr/ferrierite hybrid catalyst 认领
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作者 Qingtao Sheng Run-Ping Ye +5 位作者 Weibo Gong Xiufeng Shi Bang Xu Morris Argyle Hertanto Adidharma Maohong Fan 《环境科学学报:英文版》 SCIE EI CAS CSCD 2020年第6期106-117,共12页
Direct synthesis of dimethyl ether(DME)by CO2 hydrogenation has been investigated over three hybrid catalysts prepared by different methods:co-precipitation,sol-gel,and solid grinding to produce mixed Cu,ZnO,ZrO2 cata... Direct synthesis of dimethyl ether(DME)by CO2 hydrogenation has been investigated over three hybrid catalysts prepared by different methods:co-precipitation,sol-gel,and solid grinding to produce mixed Cu,ZnO,ZrO2 catalysts that were physically mixed with a commercial ferrierite(FER)zeolite.The catalysts were characterized by N2 physisorption,X-ray diffraction(XRD),transmission electron microscopy(TEM),X-ray photoelectron spectroscopy(XPS),temperature programmed desorption of CO2(CO2-TPD),temperature programmed desorption of NH3(NH3-TPD),and temperature programmed H2 reduction(H2-TPR).The results demonstrate that smaller CuO and Cu crystallite sizes resulting in better dispersion of the active phases,higher surface area,and lower reduction temperature are all favorable for catalytic activity.The reaction mechanism has been studied using in situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS).Methanol appears to be formed via the bidentate-formate(b-HCOO)species undergoing stepwise hydrogenation,while DME formation occurs from methanol dehydration and reaction of two surface methoxy groups. 展开更多
关键词 CO2 hydrogenation ETHER Dimethyl ether(DME)synthesis MECHANISM
脾肺两虚型重症新型冠状病毒肺炎的机制与临证探讨 认领
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作者 黄琳 郦琳 +5 位作者 杨辉 于捷 包剑峰 黄劲松 谢志军 温成平 《浙江中医药大学学报》 CAS 2020年第6期495-499,506,共6页
[目的]从脾肺两虚证与血管紧张素转化酶Ⅱ(angiotensin-converting enzyme 2,ACE2)的角度探讨新型冠状病毒肺炎(Corona Virus Disease 2019,COVID-19)普通型转为重症的机制,并结合案例探讨培元宣化解毒方抑制COVID-19普通型转为重症的... [目的]从脾肺两虚证与血管紧张素转化酶Ⅱ(angiotensin-converting enzyme 2,ACE2)的角度探讨新型冠状病毒肺炎(Corona Virus Disease 2019,COVID-19)普通型转为重症的机制,并结合案例探讨培元宣化解毒方抑制COVID-19普通型转为重症的作用。[方法]通过临床观测与相关文献分析,总结ACE2与COVID-19肺脾两虚证的关系,阐明其对普通型转为重症的影响,并列举杭州市西溪医院确诊验案一则加以佐证。[结果]文献分析显示,脾肺两虚证患者感染后易转为重症的机制与ACE2相关。病毒可竞争性结合ACE2,引起消化道及其他脏器损伤,影响机体对病毒的免疫能力。杭州市西溪医院诊治的COVID-19确诊病例中50.7%属于脾肺两虚证。所举病案诊断为COVID-19(湿毒郁肺兼脾肺两虚证),以培元宣化解毒方结合西医治疗,提高了患者免疫力和抗病毒能力,从而抑制了普通型向重症的转化。[结论]脾肺两虚型COVID-19患者转为重症的机制与ACE2密切相关,运用培元宣化解毒方抑制其转为重症具有良效。 展开更多
关键词 新型冠状病毒肺炎 重症肺炎 机制 ACE2 脾肺两虚 培元宣化解毒方 验案
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