In-situ Synthesis of ZSM-5 with Different Si/AlRatios on Honeycombshaped Cordierite and their Behavior on NO Decomposition

Thecleaningtechniquestoreduceairpollutionproducedbytheedriaustgasesfromvehicles'enginearefocusedbyresearchworkersinrecentyearsl-2.Amongthem,thecatalyticconversionofthepoisonoussubstances,suchasCO,HCandNOxintonon-orlesspoisonousonesmaybethemosteffective.Thecatalystthatiscalled"monolithiccatalyst"wascomposedofthreepartsfsubstrate,activecoatingandactivecomponents3.Thesubstrateincommonusewasthehoneycomb-shapedcordierite,whosemaincomponentwasfZMgO.ZAI,O,.SSiO,.Theactivecoatings(Y-Al,O,,zeol…     

浙江省城市韧性及其时空变化分析

我国城市化进程高速发展,城市面临的风险趋向多元化、复杂化.从城市韧性的角度出发,构建了“规模-密度-形态-基础设施”四位一体城市韧性描述体系,分析了浙江省2000年至2020年间城市韧性的时空变化,并对城市发展方向提出了建议.结果表明:在研究期间,浙江省城市韧性整体呈下降趋势,其中城市规模韧性逐年下降,存在着城市规模安全的隐患;城市密度韧性呈下降趋势,全省常年处于生态赤字风险之中;城市形态韧性整体上有所下降,但降幅较缓;城市基础设施韧性呈螺旋上升趋势,且各城市间差距逐渐缩小.浙江省的城市韧性呈现出“西高东低”梯度化的空间格局,相同韧性类型的城市也有集中分布的空间特征.根据城市韧性描述体系的研究结果,将浙江省各城市划分为高韧性城市、中韧性城市和低韧性城市三类,并分别给出城市发展方向的建议.     

氟离子选择性电极测磷化液中氟化钠

利用Ｆ＾－选择性电极,建立了测定磷化液中Ｆ＾－含量的有效方法,线性范围为０．５￣５×１０＾－６ｍｏｌ·Ｌ＾－１,回收率在８７％￣１１１％之间。方法简便,快速,准确,可用于磷化槽中磷化液的快速调整。     

Cu3V2O7(OH)2·2H2O纳米线的制备及光吸收性能

以CuSO4·5H2O和 NH4VO3为原料,采用水热法制备了Cu3V2O7(OH)2·2H2O纳米线.采用X射线衍射(XRD)和场发射扫描电子显微镜(FE-SEM)对样品的组成和表面形貌进行了表征,结果显示:Cu3V2O7(OH)2·2H2O纳米线直径约80 nm,长度达到几个微米.对纳米线形成机理研究表明:该纳米线的形成主要取决于反应温度和反应体系pH值等因素.紫外-可见光吸收测试显示Cu3V2O7(OH)2·2H2O纳米线具有较宽的紫外-可见光吸收范围,计算其带隙宽度为1.94 eV.     

近紫外光激发下KBaGd(MoO_(4))_(3)∶Er^(3+)的下转换发光及温度传感特性EI北大核心CSCD

近年来,Er^(3+)离子掺杂的无机发光材料被广泛应用于温度传感材料的研究。本文采用溶胶⁃凝胶法制备了Er^(3+)掺杂的KBaGd(MoO_(4))_(3)荧光粉,利用常温激发和发射光谱、荧光衰减曲线以及变温发射光谱对其光谱性能以及温度传感特性进行了分析。荧光光谱表明,KBaGd(MoO_(4))_(3)∶Er^(3+)在380 nm处有着较强的吸收峰,源自于Er^(3+)离子的4I_(15/2)→4G_(11/2)吸收跃迁。在近紫外光激发下,KBaGd(MoO_(4))_(3)∶Er^(3+)荧光粉在520~570 nm之间具有两个明亮的绿色发射。由于电偶极间相互作用,当Er^(3+)离子掺杂浓度超过8%时,样品发光开始出现浓度猝灭。基于荧光强度比(FIR)模型计算得到KBaGd(MoO_(4))_(3)∶Er^(3+)的相对灵敏度优于已报道的大部分同类温度传感材料,因此在光温传感领域有着更好的应用潜力。最后,对利用KBaGd(MoO_(4))_(3)∶Er^(3+)设计的LED进行了光电参数测试,并对其在照明领域的应用进行了客观评价。     

Superconductivity and unconventional density waves in vanadium-based kagome materials AV3Sb5

Recently, the discovery of vanadium-based kagome metal AV₃Sb₅ (A= K, Rb, Cs) has attracted great interest in the field of superconductivity due to the coexistence of superconductivity, non-trivial surface state and multiple density waves. In this topical review, we present recent works of superconductivity and unconventional density waves in vanadium-based kagome materials AV₃Sb₅. We start with the unconventional charge density waves, which are thought to correlate to the time-reversal symmetry-breaking orders and the unconventional anomalous Hall effects in AV₃Sb₅. Then we discuss the superconductivity and the topological band structure. Next, we review the competition between the superconductivity and charge density waves under different conditions of pressure, chemical doping, thickness, and strains. Finally, the experimental evidence of pseudogap pair density wave is discussed.     

Convex PBW-type Lyndon Bases and Restricted Two-parameter Quantum Group of Type F4

The convex PBW-type Lyndon basis for two-parameter quantum group U_r,s(F₄) is given.Assume thatrs^-1 is a primitive l-th root of unity with l odd,then the restricted quantum group u_r,s(F₄)as a quotient of U_r,s(F₄) is pointed,and of a Drinfel’d double structure under a certain condition.All of Hopf isomorphisms of u_r,s(F₄) are determined,and the necessary and sufficient condition for u_r,s(F...     

四川泸定县泥石流灾害成因、特征与防治建议

泸定县地处川西高原与四川盆地的过渡地带,地质环境条件复杂,分布泥石流沟127条,发育密度054条·10km-2。在遥感解译和地面调查基础上,论述了泸定县泥石流灾害成因、发生特征、危害和发展趋势,提出了相关防治建议。(1)成因表现为复杂的断裂构造导致流域内松散物源丰富,较大的相对高差提供了良好势能条件,而汛期集中强降雨则提供了动能条件,且雨量条件中当日雨量与前期有效降雨量之间具有幂函数关系; (2)发生特征表现出典型的空间群发性(包括2005-06-30群发性泥石流、2005-08-11群发性泥石流和2006-07-14群发性泥石流)与时间的夜发性; (3)危害方式主要包括淤埋、冲毁、侵蚀、堵河4种,泥石流已造成74人死亡; (4)发展趋势表现为泥石流沟多处于形成期和发展期(113条,占89%),发生的年际准周期由20a缩短至不足10a,且发生条(次)由4条(次)增加至44条次(2005年); (5)泸定县泥石流防治的突出问题表现为城镇泥石流问题、泥石流堵塞主河问题、风景区泥石流问题与冲沟泥石流问题,建议通过科学规划、风险防御体系构建、土木工程治理、监测预警等措施予以防御。     

基于FSVM法分岩性解释砂砾岩储层渗透率

在砂砾岩油藏中,砂岩和砂砾岩均可作为储层,不同岩性储层的渗透率特征差异大,分岩性解释渗透率是较为有效的手段,但常规方法岩性识别精度差,导致建立的渗透率模型效果不理想.本文将支持向量机(SVM)非线性识别方法推广,通过在高维空间中构造分段带状隶属函数,获得模糊支持向量机(FSVM)分类器,实现砂砾岩储层岩性精确定量识别,并以此为基础,运用多种数理统计方法分岩性建立砂砾岩储层的渗透率模型,以寻求预测砂砾岩储层渗透率的最优测井解释模型.克拉玛依油田五2东区克上组层段的应用结果表明,基于FSVM法优秀的回归能力,在砂砾岩油藏岩性识别时FSVM法的准确率更高;在砂砾岩油藏渗透率解释上,FSVM法分岩性多元逐步回归渗透率模型具有误差小、适用性强、效果好的特点.     

Design,synthesis and biological activity of some novel benzimidazole derivatives against Coxsackie virus B_3

A series of novel benzimidazole derivatives was synthesized and their anti-Coxsackie virus B_3(CVB_3) activity was evaluated in VERO cells.Compounds 9 and 10 exhibited better inhibitory activity than those of ribavirin(RBV) with IC_(50) values of 5.30 and 1.06μg/mL,respectively.