反扩散法制备介孔MCM-48分子筛膜

采用反扩散法制备介孔MCM-48分子筛膜.首先以CTAB和P123为双模板,以TEOS为硅源,合成了MCM-48晶种.采用热浸渍法在α—Al2O3载体上预涂MCM-48晶种层.MCM-48分子筛膜的制备采用反扩散法,即通过硅源(TEOS)和模板剂(CTAB)溶液分别配制,载体管内外分开装填的工艺制备介孔MCM-48膜.利用XRD、SEM及单组分气体渗透实验对制备的样品进行表征.XRD结果表明,所合成的MCM-48晶种具有良好的长程有序性及较高的规整度.从SEM照片看,合成的MCM-48粉体具有晶形,颗粒大小均匀.能够在大孔径的α—Al2O3管状载体上形成平整、致密的晶种层.MCM-48分子筛膜的SEM照片表明,膜层很薄,并且是连续致密的.室温下,制备的MCM-48分子筛膜的H2渗透率达到10-7mol/(m2·s·Pa),压降为0.1 MPa时MCM-48膜对H2/N2的分离系数达到3.0.     

1,3,5-三甲苯扩孔改性硼掺杂有序介孔炭

以F108为模板剂,1,3,5-三甲苯(TMB)为有机扩孔剂,采用溶剂挥发诱导自组装的方法成功制备出了具有较大孔径、比表面积和有序性高的硼掺杂有序介孔炭。探究了扩孔剂用量对硼掺杂介孔炭结构的影响,并对其电化学性能和扩孔机理进行了分析。结果表明,当扩孔剂与模板剂的用量比为1.5时,所得的介孔炭TMB-1.5的孔径最大(4.2nm),比表面积最高(666m~2/g)。相对于未扩孔改性的介孔炭,孔径和比表面积分别提高了5%和10%。扩孔改性后的硼掺杂介孔炭具有良好的电化学性能,在0.2A/g电流密度下的比电容高达235F/g。     

模板剂对MCM-41介孔分子筛结构的影响

以微硅粉为硅源,利用水热合成法成功制备出MCM-41介孔分子筛,利用XRD、N2吸附曲线和TEM等测试方法对样品进行了表征,结果表明,模板剂的用量对样品的结构具有显著的影响,当CTAB／SiO2的摩尔比为0．15时,样品的结构有序性最高;混合模板剂可明显提高样品的比表面积和孔容,合成的MCM-41介孔分子筛比表面积从299m2／g提高到837．3m2／g,孔容从0．051cm。／g提高到0．79cm3／g。     

Sn掺杂MCM-41介孔分子筛的制备、表征及催化性能研究

在低模板剂浓度和弱碱介质中合成催化材料Si-MCM-41、Sn-MCM-41,并用XRD、N2物理吸附-脱附、FT-IR、ICP-AES和TEM等手段对催化材料进行了表征.研究了合成方法对制备Sn掺杂MCM-41介孔分子筛的影响,结果表明:水热晶化法(DHT)合成的Sn-MCM-41,Sn物种主要进入分子筛的骨架中;而模板离子交换法(TIE)合成的Sn-MCM-41,Sn物种主要位于分子筛的表面.Sn-MCM-41介孔分子筛催化环己酮Baeyer-Villiger氧化反应结果表明,n(H2O2):n(酮)=3:1,30g1,4-二氧六环为溶剂,H2O2为氧源,70℃反应6h,环己酮的转化率可达40.02%,ε-己内酯的选择性为45.69%.     

Cu/Ti-HMS分子筛的制备及脱硫性能研究

以十二胺为模板剂,正硅酸乙酯为硅源,室温下合成了六方介孔硅(HMS)以及一系列不同n(Si)/n(Ti)的介孔分子筛Ti-HMS。并分别以HMS和Ti-HMS为载体,采用浸渍法合成了Cu-HMS和Cu/Ti-HMS分子筛。采用XRD、FT-IR、SEM等手段对其进行了表征。分别考察了硅钛比、反应时间、催化剂用量、反应温度、H2O2/S的摩尔比对Cu/Ti-HMS脱除模型油中噻吩的影响。结果表明,合成的HMS与Ti-HMS均有明显的六方介孔特征,引入Cu后六方介孔结构仍保持完好。Cu/Ti-HMS能有效地催化氧化脱除噻吩。在常压70℃时,当催化剂用量为0.1g/10mL模型油,n(H2O2)/n(S)为6,乙腈为萃取剂时,脱硫率达93.54%。     

锆掺杂MCM-41介孔分子筛的水热合成与稳定性

水热条件下,以硅酸钠和硫酸锆为原料,十六烷基三甲基溴化铵(CTAB)为模板剂,按照初始的ZrO2与SiO2物质的量之比0.05、0.1、0.2和0.3合成了4种不同锆含量的含锆介孔分子筛(ZrMCM-41).采用X射线衍射(XRD)、红外光谱(FT-IR)、透射电子显微镜(TEM)和比表面积孔径测定等方法对样品的结构和形貌进行了表征.考察了不同ZrO2与SiO2物质的量之比、不同焙烧温度以及不同水热处理时间对样品孔结构的影响.结果表明:合成的样品具有典型的MCM-41介孔结构,其比表面积为448.6~891.9 m2/g.随着样品中锆含量的增加、焙烧温度的升高和水热处理时间的延长,所合成样品的介孔有序性下降,BET比表面积降低.     

有序介孔炭的模板合成进展

以MCM-41为代表的介孔分子筛具有孔道排列规则、孔径分布窄、比表面积高等特点，在催化、吸附、分离等领域具有广泛应用前景，尤其是以其为模板开展的纳米组装科学已成为目前材料研究的热点之一。在简要介绍硅基介孔分子筛的分类和合成机理的基础上，对国内外多孔炭模板合成的研究现状进行了述评，重点阐述了有序介孔炭模板合成的特点、合成工艺、模板类型、碳前驱体的种类及其在双电层电容器、催化、储能等方面的初步应用结果，并展望了有序介孔炭模板合成的发展趋势，指出模板成本的降低、工艺条件的简化和可控化将成为未来一段时期人们研究的重点。     

短时间室温合成介孔分子筛MCM-48

以正硅酸乙酯（TEOS）为硅源、十六烷基三甲基溴化铵（CTAB）为模板剂在碱性介质中室温合成了介孔分子筛MCM-48，考察了模板剂用量、pH值、乙醇以及水的用量等条件对分子筛合成的影响。利用IR、XRD、SEM等手段对产物进行了表征。结果表明：在室温条件下pH=11．8，20min合成孔道结构规整的介孔分子筛MCM-48，其最佳配比为：n（TEOS）：n（CTAB）：n（EG）：n（H2O）=1：0．3：27：261。     

甲基官能化MCM-48分子筛的制备与表征

以甲基三甲氧基硅烷为偶联剂,用化学接枝法对MCM-48分子筛进行改性,制备了甲基官能化的MCM-48分子筛.利用FT-IR、XRD、低温N2吸附/脱附等手段对产物进行结构和性能分析.实验结果表明,硅甲基取代了MCM-48分子筛表面和孔道内羟基,成功接枝到MCM-48表面上,膜孔径、比表面积及孔体积均减小,但MCM-48保留原有立方有序结构.MCM-48分子筛甲基硅烷化改性后表面疏水性提高,水热稳定性提高.     

高可见光响应型单斜介孔BiVO4的合成与表征

利用纳米铸造法,以立方有序介孔分子筛MCM-48为硬模板,550℃成功制备了结晶良好的纯相单斜介孔BiVO4.采用XRD、TEM、BET及UV-Vis光谱分析对样品的结构进行了表征,结果表明:与水热法制备的大颗粒样品相比,"纳米铸造"介孔BiVO4的平均孔径为16.8nm,孔体积为0.1 cm2/g,比表面积高达22.9 m2/g,有效减少了光生电子和空穴复合的几率,在可见光范围内表现出优良的可见光催化活性,90min内对乙基黄原酸钾的光催化降解率高达78%.     

A Grid as Smart as the Internet

A new era of electricity is dawning that combines the decarbonization of the grid with the extensive electrification of all sectors of society. A grid as smart as the internet is needed to harness the full potential of renewables, accommodate technology disruptions, embrace the rise of prosumers, and seamlessly integrate nano-, mini-, and micro-grids. The internet is built upon a layered architecture that facilitates technology innovations, and its intelligence is distributed throughout a hierarchy of networks. Fundamental differences between data flows and power flows are examined. The current operating paradigm of the grid is based on the conviction that a centralized grid operator is necessary to maintain instantaneous power balance on the grid. A new distributed paradigm can be realized by distributing this responsibility to sub-grids and requiring each sub-grid to maintain its net power balance. A grid as smart as the internet based on this new paradigm, as well as a hierarchical network structure and a layered architecture of operating principles, is presented.     

浅谈标准样品与粮食检验和粮食安全

一、前言粮食是人类社会赖以生存和发展的生活资料,是关系国计民生的重要物资。粮食检验的对象包括原粮、成品粮油、粮油制品等;粮食检验的范围已经涉及     

建议尽早修订房屋建筑制图统一标准

ＧＢＪ１８６《房屋建筑制图统一标准》自１９８７年７月１日起实施以来,至今已经历了２０多年。在这段时间里,国家标准技术制图的陆续颁布以及计算机绘图的普及与发展,使得该标准有些内容已显得落后,并且在使用过程中,存在一些缺陷。本文提出尽早加以修订的建议,供有关人员参考。以下称ＧＢＪ１８６《房屋建筑制图统一标准》为“本标准”。一、根据国家标准《技术制图》来修订本标准《技术制图》是建筑、机械和船舶等工程制图所必须遵循的一项国家标准。自１９８９年起,至１９９６年《技术制图与机械制图》出版止,已先后颁布了…     

Against the Photograph as Memento Mori

Abstract

The photographic image imposes the idea of the past upon us, and its subject says that it is no more. We feel vaguely conscious that what we see is no longer being done, but was over and done with before appearing here. This is a déjà vécu, an already lived that wants to live again. The voices themselves rise from the grave … (Paul Valéry)¹     

科研、生产融合与工效学评价

文章论述企业要摆脱困境，在竞争中立于不败之地，必须不断推出新产品，满足消费者日益发展的需要。新产品的来源，一是靠自己开发，二是靠外部引进，三是引用科研部门的研究成果，将其转化为产品。研究成果的转化，如何更好地体现工效？作者建议强化科研与生产融合、开展成果与产品的工效学评价，使科研、生产、商业流通形成一体化，实现良性循环     

Thermistor Multivibrator as the Temperature-to-Frequency Converter and as a Bridge for Temperature Measurement

The symmetrical multivibrator, one timing resistor of which is replaced by a network consisting of a thermistor and passive resistors, is analyzed. The circuit represents at the same time a linear temperature-to-frequency (T-f) converter and a multivibrator bridge (MB), both having the same linearity range at any thermistor network configuration. When the balancing state is reached at an inflection point, the sensitivities of the converter and the bridge are the same. The MB has higher sensitivity than the Wheatstone bridge (WB) and can be balanced independently of the inflection point in the wide range. The converter and bridge performances with practical thermistor transducers are analyzed theoretically and numerically.     

加入WTO对包装业的影响及应对措施

分析了我国加入WTO后包装业发展所面临的机遇和挑战,指出了包装业应从转变观念、把企业生产经营的立足点转向国际国内两个市场,抓紧创新改革,实现技术升级,努力增加出口等方面迎接挑战。     

试论中医学的性质与特点，中医理论的形成与发展

论述了中医学的性质与特点，以及中医理论的形成与发展。中医理论来源于实践，是古人长期与疾病斗争的大量实践，从实践经验的积累、综合到感性认识上升为理性认识，并广泛借鉴古代哲学、人文科学的思想、方法、世界观，逐渐形成以整体观为特点的系统化、理论化的中医理论；强调了中医药现代化的目的是全面提高中医药防病治病能力，不断发展创新；讨论了中医理论现代化的内容、重点及注意事项进行。     

Modelling the heart as a communication system

Electrical communication between cardiomyocytes can be perturbed during arrhythmia, but these perturbations are not captured by conventional electrocardiographic metrics. We developed a theoretical framework to quantify electrical communication using information theory metrics in two-dimensional cell lattice models of cardiac excitation propagation. The time series generated by each cell was coarse-grained to 1 when excited or 0 when resting. The Shannon entropy for each cell was calculated from the time series during four clinically important heart rhythms: normal heartbeat, anatomical reentry, spiral reentry and multiple reentry. We also used mutual information to perform spatial profiling of communication during these cardiac arrhythmias. We found that information sharing between cells was spatially heterogeneous. In addition, cardiac arrhythmia significantly impacted information sharing within the heart. Entropy localized the path of the drifting core of spiral reentry, which could be an optimal target of therapeutic ablation. We conclude that information theory metrics can quantitatively assess electrical communication among cardiomyocytes. The traditional concept of the heart as a functional syncytium sharing electrical information cannot predict altered entropy and information sharing during complex arrhythmia. Information theory metrics may find clinical application in the identification of rhythm-specific treatments which are currently unmet by traditional electrocardiographic techniques.