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Facet effect of metal-organic frameworks on supporting co-catalysts for photocatalytic hydrogen peroxide production
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作者 Peiyang Du Ling Yuan +6 位作者 Tong Bao Yamin Xi Jiaxin Li Yin Bi Luli Yin Jing Wang Chao Liu 《Chinese Chemical Letters》 2025年第11期541-545,共5页
The facet effect of metal-organic frameworks(MOF)on regulating the property of loaded co-catalysts is an important but unexplored issue in the field of photocatalysis.In this work,a series of MIL-125-NH_(2)polyhedrons... The facet effect of metal-organic frameworks(MOF)on regulating the property of loaded co-catalysts is an important but unexplored issue in the field of photocatalysis.In this work,a series of MIL-125-NH_(2)polyhedrons(MIL=Materials Institute Lavoisier)with facet exposure of{001},{001}/{111}and{111}are synthesized and used to load Pd-based co-catalysts for photocatalytic oxygen reduction reaction(ORR)toward H_(2)O_(2)production.The different facets with distinct chemical environments(Ti-O clusters on{111}facets and carboxyl ligands on{001}facets)result in the selective loading of Pd0and PdO dominated cocatalysts on{001}and{111}facets,respectively.The{001}/{111}co-exposed MIL-125-NH_(2)thus enables the spatially separated loading of Pd0and Pd O dual cocatalysts respectively.Pd0efficiently traps the photoexcited electrons and PdO trends to capture the holes,collaboratively promoting the directional separation of photogenerated electron-hole pairs.As a result,the photocatalytic ORR activity is significantly enhanced with a H_(2)O_(2)production rate of 128.6 mmol L^(-1)g^(-1)h^(-1),superior than pristine and single cocatalyst modified MIL-125-NH_(2)samples.Our findings provide new insight into the design of high-performance photocatalysts. 展开更多
关键词 facet effect PHOTOCATALYST CO-CATALYST MOF H_(2)O_(2) production
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Facet effect on the reconstructed Cu-catalyzed electrochemical hydrogenation of 5-hydroxymethylfurfural(HMF) towards 2,5-bis(hydroxymethy)furan (BHMF) 被引量:2
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作者 Mengxia Li Tianxi Zheng +7 位作者 Dongfei Lu Shiwei Dai Xin Chen Xinchen Pan Dibo Dong Rengui Weng Gang Xu Fanan Wang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第9期101-111,共11页
The electrochemical hydrogenation of HMF to BHMF is an elegant alternative to the conventio nal thermocatalytic route for the production of high-value-added chemicals from biomass resources.In virtue of the wide poten... The electrochemical hydrogenation of HMF to BHMF is an elegant alternative to the conventio nal thermocatalytic route for the production of high-value-added chemicals from biomass resources.In virtue of the wide potential window with promising Faradic efficiency(FE) towards BHMF,Cu-based electrode has been in the center of investigation.However,its structure-activity relationship remains ambiguous and its intrinsic catalytic activity is still unsatisfactory.In this work,we develop a two-step oxidation-reduction strategy to reconstruct the surface atom arrangement of the Cu foam(CF).By combination of multiple quasi-situ/in-situ techniques and density functional theory(DFT) calculation,the critical factor that governs the reaction is demonstrated to be facet effect of the metallic Cu crystal:Cu(110) facet accounts for the most favorable surface with enhanced chemisorption with reactants and selective production of BHMF,while Cu(100) facet might trigger the accumulation of the by-product 5,5'-bis(hydroxy methy)hydrofurion(BHH).With the optimized composition of the facets on the reconstructed Cu(OH)_(2)-ER/CF,the performance could be noticeably enhanced with a BHMF FE of 92.3% and HMF conversion of 98.5% at a potential of -0.15 V versus reversible hydrogen electrode(vs.RHE) in 0.1 M KOH solution.This work sheds light on the incomplete mechanistic puzzle for Cu-catalyzed electrochemical hydrogenation of HMF to BHMF,and provides a theoretical foundation for further precise design of highly efficient catalytic electrodes. 展开更多
关键词 Electrochemical hydrogenation Biomass conversion 5-HYDROXYMETHYLFURFURAL Cu electrode facet effect
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Hydrothermal shape controllable synthesis of La_(0.5)Sr_(0.5)MnO_(3) crystals and facet effect on electron transfer of oxygen reduction
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作者 Keke Huang Long Yuan +4 位作者 Yilan Jiang Jiaxin Zhang Zhibin Geng Liqun Luo Shouhua Feng 《Inorganic Chemistry Frontiers》 2018年第3期732-738,共7页
Controllable growth of perovskite structure oxide crystals with well-defined facets is challenging,especially in the mixed-valence state manganites with both rare-earth and alkaline-earth cations in their A-site.In th... Controllable growth of perovskite structure oxide crystals with well-defined facets is challenging,especially in the mixed-valence state manganites with both rare-earth and alkaline-earth cations in their A-site.In this paper,we systematically studied the effects of the synthetic conditions of mineralizer concentration,reaction temperature and facet directing agent on the crystal shape formation of La_(0.5)Sr_(0.5)MnO_(3).The shapes of single crystal La_(0.5)Sr_(0.5)MnO_(3) have been controllably grown as cube,octahedron,rhombicuboctahedron and sphere by a high concentration KOH mineralized mild hydrothermal method with urea(CO(NH_(2))_(2))as crystal facet directing agent.The crystal growth mechanism for different facets has been analyzed according to Bravais−Friedel−Donnay−Harker theory.The as-grown facets for the different shapes of crystals indicate that the surfaces of La_(0.5)Sr_(0.5)MnO_(3) are composed of{100},{110}and{111}facets.Electrochemical cyclic and linear sweeping voltammetry measurement by rotating ringdisk electrode of these crystals indicates a facet-dependent process for oxygen reduction catalysis.This work provides a useful strategy for growing high index crystal facets of complex oxides and materials for crystal-facet dependent physico-chemical applications. 展开更多
关键词 crystal shape control facet directing agent synthetic conditions hydrothermal synthesis perovskite structure facet effect perovskite structure oxide crystals oxygen reduction
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A solvent-induced crystal-facet effect of nickel-cobalt layered double hydroxides for highly efficient overall water splitting
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作者 Lingxing Zan Hongling Zhang +8 位作者 Zhangwen Ye Qingbo Wei Hongliang Dong Shiwen Sun Qiang Weng Xin Bo Huicong Xia Yibing Li Feng Fu 《Inorganic Chemistry Frontiers》 2022年第21期5527-5537,共11页
Two-dimensional layered materials have been universally acknowledged to be promising candidates for alternative precious metals in the field of catalysis.The crystal-facet effect is currently rare in the field of elec... Two-dimensional layered materials have been universally acknowledged to be promising candidates for alternative precious metals in the field of catalysis.The crystal-facet effect is currently rare in the field of electrocatalysis and a deep understanding of the catalytic mechanism of bimetallic highly active crystal facets is critical for fabricating high-performance catalysts,but details are still lacking.Herein,we demonstrated a solvent-induced strategy to manufacture well-defined structured CoNi-layered double hydroxides(LHDs)for highly efficient water electrolysis,and gave a detailed mechanism of catalytic activity towards an enhanced OER.Such considerable improvement in catalytic activity was attributed not only to the synergistic catalytic effect of bimetallic hydroxides,but also to the crystal-facet effect,which is caused by the high density of unsaturated-coordination of surface metal atoms.Consequently,the adsorption energy was enhanced and the activation energy of the target reaction was lowered.These unsaturated coordination surface or edge metal atoms can be easily oxidized to form a great amount of active oxyhydroxides,such as β-NiOOH intermediates.In addition,the adjacent Co sites can also regulate the redox reaction kinetics of Ni(OH)_(2)/NiOOH and synergistically catalyze the OER. 展开更多
关键词 catalytic mechanism bimetallic highly active crystal facets overall water splitting solvent induced crystal facet effect adsorption energy nickel cobalt layered double hydroxides electrocatalysis bi metallic hydroxides
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Facets-controllable synthesis of metal-organic frameworks via one supersaturation strategy to insight intrinsic facets effect
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作者 Lifang Liu Yejun Xiao +2 位作者 Xiangyang Guo Shengye Jin Fuxiang Zhang 《Chinese Journal of Catalysis》 2025年第6期153-158,共6页
The facets effect on the catalytic properties of inorganic compounds and metal-organic frameworks(MOFs)has been widely demonstrated,but the intrinsic facets effect free of interference of capping agents has not been d... The facets effect on the catalytic properties of inorganic compounds and metal-organic frameworks(MOFs)has been widely demonstrated,but the intrinsic facets effect free of interference of capping agents has not been discussed.Here we give a proof-of-concept illustration on the intrinsic facets effect by employing the popularly investigated NH2-MIL-125(Ti)MOFs with{001},{111}and{100}facets controllably exposed as model photocatalysts,which were synthesized via a simple supersaturation strategy free of any capping agents.Compared to conventional synthetic routes with capping agents employed,the NH2-MIL-125(Ti)MOFs obtained in this work exhibit remarkably different physical and chemical properties such as surface wettability,charge separation as well as trend of facets effect on photocatalytic water splitting performance.The main reason has been unraveled to originate from unavoidable residue/influence of capping agents during the conventional facets-controlled synthetic routes leading to changed local surface structural environment as well as distinct charge separation property.Our results demonstrate the importance and feasibility of facets-controllable synthesis free of capping agents in getting insight into the intrinsic facets effect of MOFs-related materials. 展开更多
关键词 Metal-organic framework facets-controllable synthesis SUPERSATURATION Intrinsic facets effect Photocatalyst
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腰椎斜扳法联合小针刀松解治疗腰椎小关节紊乱症40例
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作者 董兆杰 邓素玲 《中国中医骨伤科杂志》 2026年第2期93-96,共4页
目的:观察腰椎斜扳法联合小针刀松解治疗腰椎小关节紊乱症的临床疗效。方法:收集2023年2月至2025年2月诊治的80例腰椎小关节紊乱患者,用随机数字表法平分为观察组和对照组,对照组给予腰椎斜扳法治疗,观察组给予腰椎斜扳法联合小针刀松... 目的:观察腰椎斜扳法联合小针刀松解治疗腰椎小关节紊乱症的临床疗效。方法:收集2023年2月至2025年2月诊治的80例腰椎小关节紊乱患者,用随机数字表法平分为观察组和对照组,对照组给予腰椎斜扳法治疗,观察组给予腰椎斜扳法联合小针刀松解治疗。比较两组患者临床疗效、腰痛压痛值、疼痛介质水平、Oswestry功能障碍指数(ODI)评分。结果:观察组总有效率高于对照组,差异有统计学意义(P<0.05);首次治疗及末次治疗后,两组患者腰痛压痛值均升高,且观察组高于对照组,差异有统计学意义(P<0.05);治疗后,两组患者5-HT、PGE_(2)水平均降低,且观察组低于对照组,差异有统计学意义(P<0.05);治疗后,两组患者ODI评分均降低,且观察组低于对照组,差异有统计学意义(P<0.05)。结论:腰椎斜扳法联合小针刀松解治疗腰椎小关节紊乱症,能够明显减轻疼痛,恢复腰椎功能,临床疗效佳。 展开更多
关键词 腰椎小关节紊乱 腰椎斜扳法 小针刀松解 疗效
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Sulfuric acid etching CeO_(2)nanoparticles to promote high KA-Oil selectivity in cyclohexane selective oxidation
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作者 Shuang Wei Yingwei Li +4 位作者 Longlong Wang Kexin Li Bin He Ruirui Zhang Ruixia Liu 《Chinese Journal of Chemical Engineering》 2025年第5期151-160,共10页
Nanostructured ceria has attracted much attention in the field of redox catalysts due to the numerous active sites with excellent redox ability.Based on the acidic medium etching strategy,we constructed the strong bin... Nanostructured ceria has attracted much attention in the field of redox catalysts due to the numerous active sites with excellent redox ability.Based on the acidic medium etching strategy,we constructed the strong binding centers(hydroxyl sites and strong acid sites)on the surfaces of nanostructured ceria,which regulate the adsorption process of KA-Oil(the mixture of cyclohexanol and cyclohexanone)and to promote high KA-Oil selectivity in cyclohexane oxidation.The three CeO_(2)(nanocube,nanorod and nanopolyhedron)with different exposed crystal planes were treated by acid etching to change the surface sites and catalytic properties.The transition behavior of surface sites during etching was revealed,abundant strong binding centers were proved to be constructed successfully.And especially for the nanorod treated by acid(Acid@CeO_(2)-NR)with the strongest response for sulfuric acid etching,the strong adsorption of cyclohexanone by strong binding centers was confirmed based on the in-situ DRIFTs.The sulfuric acid etching strategy to enhance the selective oxidation of cyclohexane based on the construction of strong binding centers was proved to be feasible and effective,Acid@CeO_(2)-NR with strongest etching response achieved the dramatic promotion of KA-Oil selectivity from 64.1%to 92.3%. 展开更多
关键词 Nanostructured CeO_(2) Defect engineering Cyclohexane oxidation Crystal facet effect Acid site
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反相催化剂的研究进展:影响因素及其应用
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作者 杨雪滢 许志志 +2 位作者 赖峻宇 罗永明 陆继长 《材料导报》 北大核心 2025年第21期140-150,共11页
反相催化剂是一种将少量氧化物纳米颗粒均匀分散在活性组分(金属或金属氧化物)表面的固体催化剂。这种催化剂通过调整界面性质增加了界面活性位点密度,并利用表面氧化物纳米颗粒对金属活性相进行物理隔离,从而显著提升了催化性能,引起... 反相催化剂是一种将少量氧化物纳米颗粒均匀分散在活性组分(金属或金属氧化物)表面的固体催化剂。这种催化剂通过调整界面性质增加了界面活性位点密度,并利用表面氧化物纳米颗粒对金属活性相进行物理隔离,从而显著提升了催化性能,引起了众多研究者的关注。本文以传统负载型催化剂为切入点,重点介绍了反相催化剂相对于传统催化剂的优势,归纳了反相催化剂的制备方法,深入探讨了界面相互作用、晶面效应、尺寸效应等因素对催化剂性能的关键影响。最后,通过分析该催化剂在热催化、电催化和光催化领域的应用,展望了未来反相催化剂制备及应用的发展方向。 展开更多
关键词 反相催化剂 多相催化 界面作用 晶面效应 催化应用
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重掺锑直拉硅单晶中管道问题的数值模拟
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作者 李晓川 马三宝 +3 位作者 周锋子 任永鹏 马武祥 梅昊天 《人工晶体学报》 北大核心 2025年第9期1534-1546,共13页
在<111>晶向重掺锑硅单晶晶棒拉制过程中经常出现由于小平面效应而产生的中心管道,从而影响硅片最终质量,因此迫切需要解决此问题。本研究针对8英寸(1英寸=2.54 cm)直拉重掺锑硅单晶中心管道问题提出理论解决方案并采用CGSim软件... 在<111>晶向重掺锑硅单晶晶棒拉制过程中经常出现由于小平面效应而产生的中心管道,从而影响硅片最终质量,因此迫切需要解决此问题。本研究针对8英寸(1英寸=2.54 cm)直拉重掺锑硅单晶中心管道问题提出理论解决方案并采用CGSim软件进行模拟验证。结果表明:增大拉晶速度(V)和晶体旋转速度(M)同时减小坩埚旋转速度(N)可以有效抑制小平面效应,显著改善固液界面形状、增大温度梯度、增大固液界面附近熔体流速,有效减小晶体热应力。最佳的工艺参数为:V=0.7 mm/min、M=17 r/min、N=-7 r/min。 展开更多
关键词 重掺锑硅单晶 管道问题 小平面效应 数值模拟
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Ethanol-water ambient precipitation of{111}facets exposed Ag_(3)PO_(4) tetrahedra and its hybrid with graphene oxide for outstanding photoactivity and stability
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作者 Guo-Ying Zhang Xue-Min Wei +3 位作者 Xue Bai Chun-Mei Liu Bing-Yu Wang Jing-Wang Liu 《Inorganic Chemistry Frontiers》 2018年第4期951-961,共11页
This study presents the combinative merits of facet effect and the graphene oxide(GO)hybrid of Ag_(3)PO_(4) photocatalyst.First,Ag_(3)PO_(4) tetrahedra with exposed{111}facets were controllably prepared via an ethanol... This study presents the combinative merits of facet effect and the graphene oxide(GO)hybrid of Ag_(3)PO_(4) photocatalyst.First,Ag_(3)PO_(4) tetrahedra with exposed{111}facets were controllably prepared via an ethanol-water ion exchange strategy at room temperature.The amount of ethanol was crucial to regulate the orientation growth of Ag_(3)PO_(4) crystals along{111}planes through the balance of coordination and adsorption.The sample exhibited an enhanced visible-light photocatalytic efficiency of 3.3-fold for pollutant degradation as compared to that of Ag_(3)PO_(4) particles due to the active facets.GO/Ag_(3)PO_(4) hybrid was then constructed based on the electrostatic interaction between Ag^(+)enriched{111}facets and negatively charged GO sheets.The photocatalytic activity of the hybrid increased by 4.6-fold with admirable recyclability as compared to that of the bare Ag_(3)PO_(4) tetrahedra.Systematical optical and photoelectrochemical characterizations revealed that the hybrid exhibits extended light absorption and significantly accelerated carrier transfer due to the coaction of unique charge mobility of GO,electronic effect of trace Ag and increased catalytic active sites.A possible migration mechanism of photoinduced carriers at the interface of GO/Ag_(3)PO_(4) tetrahedron is proposed based on the above analyses,detected oxidative species and band positions of Ag_(3)PO_(4) tetrahedra.This study provides new insight into the rational design of carbonaceous material-hybridized semiconductor photocatalysts with facet dependency. 展开更多
关键词 facets Catalytic active sites facet effect Photocatalytic efficiency Carrier transfer Graphene oxide hybrid Ag PO tetrahedra ethanol water ambient precipitation
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Ag3PO4表面热力学性质及光催化原位过程热动力学的晶面效应 被引量:14
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作者 肖明 黄在银 +2 位作者 汤焕丰 陆桑婷 刘超 《物理化学学报》 SCIE CAS CSCD 北大核心 2017年第2期399-406,共8页
采用湿化学法制备了立方体{100}、四面体{111}和菱形十二面体{110}磷酸银微晶,通过场发射扫描电镜(FE-SEM),X射线粉末衍射(XRD),固体紫外可见漫反射光谱(UV-Vis DRS),光电流,光致发光(PL)对催化剂的组分、结构、形貌及光电性质进行了系... 采用湿化学法制备了立方体{100}、四面体{111}和菱形十二面体{110}磷酸银微晶,通过场发射扫描电镜(FE-SEM),X射线粉末衍射(XRD),固体紫外可见漫反射光谱(UV-Vis DRS),光电流,光致发光(PL)对催化剂的组分、结构、形貌及光电性质进行了系统表征。以罗丹明B(Rh B)为目标污染物,对不同形貌Ag_3PO_4微晶的可见光催化活性进行了探究。通过微热量技术结合过渡态理论和热化学循环原理对Ag_3PO_4的摩尔表面Gibbs自由能进行了测定,其数值分别为1.2972、0.9621、0.5414 k J?mol-1。采用自主设计的新型LED光-微热量系统获取了Ag_3PO_4原位光催化降解Rh B 2 h的热效应和稳定放热阶段的热焓变化率,并对其热谱曲线进行了合理的解析。结果表明,Ag_3PO_4的催化活性与原位光催化降解Rh B的热效应、热焓变化率以及摩尔表面Gibbs自由能皆呈正相关。此外,通过捕获剂实验和电子顺磁共振(ESR)确定了Ag_3PO_4光催化降解Rh B过程的主要活性基团。 展开更多
关键词 磷酸银 表面热力学 原位光量热 光催化 晶面效应
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光纤端面处理对光纤激光器输出性能的影响 被引量:3
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作者 朱辰 李尧 +2 位作者 王雄飞 林佶翔 赵鸿 《激光与红外》 CAS CSCD 北大核心 2008年第5期447-450,共4页
从光纤端面的不同处理方法(抛磨法、切割法)入手,对各自工艺展开了较深入的探索,测试了经不同方法处理后光纤端面的表面粗糙度:抛磨端面的表面粗糙度达到0.6nm,切割端面的表面粗糙度为24nm。研究了不同端面处理方法对光纤激光器输出性能... 从光纤端面的不同处理方法(抛磨法、切割法)入手,对各自工艺展开了较深入的探索,测试了经不同方法处理后光纤端面的表面粗糙度:抛磨端面的表面粗糙度达到0.6nm,切割端面的表面粗糙度为24nm。研究了不同端面处理方法对光纤激光器输出性能(输出功率、光束质量)的影响。 展开更多
关键词 光纤激光器 高功率 热效应 端面损伤
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预防CCU心肌梗死患者感染的护理研究 被引量:4
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作者 王素倩 翟建芬 +1 位作者 贾金广 徐彦立 《中华医院感染学杂志》 CAS CSCD 北大核心 2015年第8期1801-1802,1819,共3页
目的探讨冠心病监护病房(CCU)心肌梗死患者发生感染的预防方法,分析使用多方位护理心肌梗死患者,得出预防感染的经验,为临床治疗提供参考依据。方法调查2013年1-12月医院进行治疗的100例心肌梗死患者临床资料,随机平均分为对照组和观察... 目的探讨冠心病监护病房(CCU)心肌梗死患者发生感染的预防方法,分析使用多方位护理心肌梗死患者,得出预防感染的经验,为临床治疗提供参考依据。方法调查2013年1-12月医院进行治疗的100例心肌梗死患者临床资料,随机平均分为对照组和观察组,每组各50例;对照组患者采用一般的护理措施,观察组患者采用基本护理加多方位护理的方法进行护理,比较两种护理方法的优劣,采用SPSS 17.0软件进行统计分析。结果经过对于两组患者的护理效果参考指标的统计调查和比较,发现治愈率等各项指标参数观察组均优于对照组(P<0.05),观察组的患者感染率比对照组更低。结论经过两组患者的对比研究,发现使常规护理方法结合多方位护理,对于心肌梗死患者的护理效果更好,可以有效地减少患者感染率,提高治愈率。 展开更多
关键词 心肌梗死 冠心病监护病房 多方位护理 效果
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CO hydrogenation on stepped Cu and CuZn alloy surfaces:Competition between methanol synthesis and methanation pathways 被引量:1
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作者 Xuanye Chen Wenhua Zhang Weixin Huang 《Chinese Chemical Letters》 SCIE CAS CSCD 2023年第7期463-466,共4页
Comprehensive fundamental understanding of CO hydrogenation reactions over Cu and ZnCu alloy surfaces is of great importance.Herein,we report a comparative DFT calculation study of elementary surface reaction network ... Comprehensive fundamental understanding of CO hydrogenation reactions over Cu and ZnCu alloy surfaces is of great importance.Herein,we report a comparative DFT calculation study of elementary surface reaction network of CO hydrogenation reactions on stepped Cu(211),Cu(611),ZnCu(211) and ZnCu(611)surfaces.On Zn Cu(211) and Zn Cu(611) surfaces,the energetic favorable reaction path of CO hydrogenation reaction follows CO^(*)→HCO^(*)→H_(2)CO^(*)→H_(3)CO^(*)→CH_(3)OH^(*)→CH_(3)OH with H_(3)CO^(*)hydrogenation as the rate-limiting step and proceeds more facilely on ZnCu(611) surface than on ZnCu(211) surface.On Cu(211) and Cu(611) surfaces,the energetic favorable reaction path of CO hydrogenation reaction follows CO^(*)→HCO^(*)→HCOH^(*)→H_(2)COH^(*)→H_(3)COH^(*)→CH_(3)^(*)→CH_(4)^(*)→CH_(4) with H_(2)COH^(*) hydrogenation as the rate-limiting step and proceeds more facilely on Cu(611) than on Cu(211).The key difference of CO hydrogenation reaction on Zn Cu alloy surface and Cu is that the resulting CH_(3)OH^(*) species desorbs to produce CH_(3)OH on ZnCu alloy but undergoes H^(*)-assisted decomposition to CH_(3)^(*) and eventually to CH_(4) on Cu surface.These results successfully unveil elementary surface reaction networks and structure sensitivity of Cu and Zn Cu alloy-catalyzed CO hydrogenation reactions. 展开更多
关键词 Theoretical calculation Reaction mechanism Structure-activity relation facet effect Defect
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基于等级反应模型的多水平多侧面评分者模型 被引量:5
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作者 康春花 孙小坚 曾平飞 《心理科学》 CSSCI CSCD 北大核心 2016年第1期214-223,共10页
国内外考试改革和大型测评实践越来越强调主观题的作用,则评分者信度研究又重新成为一个备受关注的议题。研究在Wang和Liu(2007)的广义多水平侧面模型基础上,提出并探讨了等级反应多水平侧面模型。结果表明:在评分者固定效应和随机效应... 国内外考试改革和大型测评实践越来越强调主观题的作用,则评分者信度研究又重新成为一个备受关注的议题。研究在Wang和Liu(2007)的广义多水平侧面模型基础上,提出并探讨了等级反应多水平侧面模型。结果表明:在评分者固定效应和随机效应两种实验条件下,各偏差值的均值与标准差均较小,说明模型在当前实验条件下,各参数估计值的返真性和稳健性均较好,可以检测出评分者效应,由此,后续可进一步加入评分者效应的影响因素,使其发展为可同时检测评分者效应及其影响因素的完整模型。 展开更多
关键词 主观评分 评分者效应 等级反应多水平侧面模型
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语言测试研究中的多层面Rasch模型——原理简介和研究综述 被引量:12
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作者 张洁 《外语测试与教学》 2014年第3期50-59,共10页
语言运用测试(language performance assessment)是各种大规模语言考试中不可或缺的部分,但因为其测试环境中不可避免地引入了评分员的主观判断、测试任务的难度、评分标准的设定和使用情况等因素,使其信度、效度及考试的公平性都受到... 语言运用测试(language performance assessment)是各种大规模语言考试中不可或缺的部分,但因为其测试环境中不可避免地引入了评分员的主观判断、测试任务的难度、评分标准的设定和使用情况等因素,使其信度、效度及考试的公平性都受到了质疑。多层面Rasch模型是项目反应理论(IRT)中经典Rasch模型在多个维度上的延伸,它的主要优势在于可以将考试环境中多个影响考生最终得分的因素纳入同一个数学模型中进行分析,并估算出各个层面的因素对考生成绩的影响程度。本文旨在对MFRM的工作原理和基本模型进行简单介绍,并系统梳理语言测试领域运用MFRM进行的相关研究,以期让读者更好地了解如何在语言测试研究中有效地运用这种统计方法。 展开更多
关键词 语言运用测试 多层面RASCH模型 评分员效应
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宝石刻面琢型款式的设计方法 被引量:3
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作者 潘峰 曲丹 《宝石和宝石学杂志》 CAS 2017年第3期59-63,共5页
近年来,随着宝石刻面切磨技术的不断进步以及宝石琢型设计理论研究的深入,出现了各种各样的琢型款式。计算机在宝石琢型研究和设计中的应用使设计工作快捷、高效且数据精确。本文以刻面型和异形宝石琢型设计开发为研究对象,为满足市场... 近年来,随着宝石刻面切磨技术的不断进步以及宝石琢型设计理论研究的深入,出现了各种各样的琢型款式。计算机在宝石琢型研究和设计中的应用使设计工作快捷、高效且数据精确。本文以刻面型和异形宝石琢型设计开发为研究对象,为满足市场对异形琢型款式日渐增多的需求,结合现代美学艺术和美学思想,运用计算机辅助设计手段探讨了宝石刻面琢型款式的创新设计方法。研究步骤:首先确定刻面琢型的设计主题,运用计算机软件GemCad对新琢型款式的形态和刻面进行总体规划,建立新款式的折光率模型;然后,利用3D打印技术输出新款式的模型;最后,运用精湛手工工艺琢磨出符合主题的刻面宝石。以风车系列设计作品为例,详细阐释了宝石刻面琢型的创新设计方法,验证了该设计方法的有效性和可行性。 展开更多
关键词 刻面琢型 整体造型 光学效果 设计方法
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基于IRT的评分者效应模型及其应用展望 被引量:4
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作者 康春花 辛涛 《中国考试》 2010年第8期3-8,共6页
在教育测验理论与实践中,开放题或结构化题型越来越成为一种重要形式,当这种题型由多个评分者进行多重评定时.就必须考虑评分者偏差以及被试能力值估计的精确性.而基于IRT的评分者效应模型由于突破了CTT的局限而备受青睐。本文在介... 在教育测验理论与实践中,开放题或结构化题型越来越成为一种重要形式,当这种题型由多个评分者进行多重评定时.就必须考虑评分者偏差以及被试能力值估计的精确性.而基于IRT的评分者效应模型由于突破了CTT的局限而备受青睐。本文在介绍了三种比较有代表性的基于IRT的评分者效应模型基础上,对其在实践中的应用进行了展望。 展开更多
关键词 评分者效应 多面RASCH模型 评委束模型 阶层评分者模型
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单侧经皮椎体成形术结合小关节囊封闭术治疗高龄骨质疏松性胸腰椎骨折的疗效观察 被引量:3
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作者 张羽浩 郑飞 《当代医学》 2021年第16期87-89,共3页
目的探讨单侧经皮椎体成形术(percutaneous vertebroplasty,PVP)结合小关节囊封闭术应用于高龄骨质疏松性胸腰椎骨折患者中的临床价值。方法选取2015年1月至2018年1月本院收治的高龄骨质疏松性胸腰椎骨折患者68例作为研究对象,随机分为... 目的探讨单侧经皮椎体成形术(percutaneous vertebroplasty,PVP)结合小关节囊封闭术应用于高龄骨质疏松性胸腰椎骨折患者中的临床价值。方法选取2015年1月至2018年1月本院收治的高龄骨质疏松性胸腰椎骨折患者68例作为研究对象,随机分为研究组与对照组,每组34例。对照组行单侧经皮椎体成形术,研究组在对照组基础上行小关节囊封闭术治疗,比较两组术后相关指标、术后VAS评分及奥斯沃斯特里残疾指数(oswestry disability index,ODI)。结果两组手术时间、骨水泥注入量比较差异有统计学意义(P<0.05);两组椎体压缩改善程度、Cobb角矫正度数比较差异无统计学意义。术后24 h及3、6个月,研究组VAS评分明显低于对照组,差异有统计学意义(P<0.05)。术后24 h及3、6个月,研究组ODI指数均明显低于对照组,差异有统计学意义(P<0.05)。结论单侧经椎弓根入路PVP手术结合小关节囊封闭术应用于高龄骨质疏松性胸腰椎骨折患者疗效显著,对减轻术后疼痛,改善椎体压缩程度、保障手术效果等方面均具有积极意义。 展开更多
关键词 单侧经皮椎体成形术 小关节囊封闭术 高龄 骨质疏松性胸腰椎骨折 疗效
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手法复位治疗腰椎关节突关节综合征的临床疗效观察 被引量:4
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作者 吴朔 张诚 +1 位作者 胡林海 田继东 《中医临床研究》 2015年第13期41-42,共2页
目的:观察手法复位治疗腰椎关节突关节综合征的临床疗效及安全评估。方法:借鉴前辈侧板、挤压复位手法、参照De Seze手法原理,设计一种复位手法,自2012年7月-2014年9月治疗腰椎关节突关节综合征共42例,与观察组对照,疗效明显,使用JOA下... 目的:观察手法复位治疗腰椎关节突关节综合征的临床疗效及安全评估。方法:借鉴前辈侧板、挤压复位手法、参照De Seze手法原理,设计一种复位手法,自2012年7月-2014年9月治疗腰椎关节突关节综合征共42例,与观察组对照,疗效明显,使用JOA下腰痛评分系统评分,评估临床疗效。结果:治疗后评分明显升高,疗效立竿见影,缩短病程,减轻患者病痛,能明显减轻患者的症状体征、改善患者的腰部功能。治疗过程中无明显手法意外,无并发症发生。结论:本手法复位治疗腰椎关节突关节综合征安全有效,未见不良反应,值得推广。 展开更多
关键词 复位手法 腰椎关节突关节综合征 疗效观察
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