Al2O3中空纤维陶瓷膜上TS-1膜的制备

采用相转化纺丝／烧结技术制备Al2O3多孔中空纤维膜,并以此为载体,通过晶种法考察不同晶种诱导条件制备TS-1复合中空纤维膜,并采用扫描电子显微镜、气体渗透性能测试装置等设备对所制备的TS-1复合中空纤维膜进行微观结构及渗透性能的表征。结果表明,晶种法制备的TS-1复合中空纤维膜的N2渗透速率较小,并且表面平整无缺陷,因此该方法适合制备性能优良的TS-1复合中空纤维膜。     

Organosilane deposition for microfluidic applications

Treatment of surfaces to change the interaction of fluids with them is a critical step in constructing useful microfluidics devices, especially those used in biological applications. Silanization, the generic term applied to the formation of organosilane monolayers on substrates, is both widely reported in the literature and troublesome in actual application for the uninitiated. These monolayers can be subsequently modified to produce a surface of a specific functionality. Here various organosilane deposition protocols and some application notes are provided as a basis for the novice reader to construct their own silanization procedures, and as a practical resource to a broader range of techniques even for the experienced user.     

有机改性沸石对水中多环芳烃的吸附性能研究

研究十六烷基三甲基溴化铵(CTMAB)有机改性沸石对水中2种典型多环芳烃(PAHs)菲、蒽的吸附性能。结果表明,Langmuir和Freundlich等温吸附方程均可以很好地描述有机改性沸石对菲、蒽的吸附行为;菲、蒽在有机改性沸石上的吸附主要受温度的影响,吸附随温度的上升而减少,说明吸附是放热行为。     

珊瑚尾矿在水泥生产中的应用研究

提取三组珊瑚尾矿渣与沸石进行成份比较,初步确认可用珊瑚尾矿替代沸石在水泥粉磨工序中做为混合材掺加。将三组珊瑚尾矿以5种不同掺加量共配成15个样品,在实验室球磨机加入0.8‰的液体助磨剂各粉磨30分钟。分析样品结果表明:各配比样品间的化学成份和物理性能差别不大;强度随着珊瑚尾矿掺量的增加有小幅下降,但均在国家标准控制范围内。在?3.8×13m水泥粉磨生产线进行珊瑚尾矿替代沸石工业试验,尾矿掺加量为10%。试验水泥化学成份和物理性能均满足了GB175-2007标准的要求;以试验水泥做混凝土试块,经相关建材检测机构检测,均符合要求。证明了将珊尾矿掺量控制在10%来替代沸石做混合材是完全可行的,并具有良好的社会和经济效益。     

CO2和乙醇反应合成乙酸乙酯的研究

探索催化剂的最佳制备条件及合成反应的最佳工艺条件,从而使C02和乙醇反应合成乙酸乙酯具有较高的选择性和收率。结果表明：用氢氧化钠作沉淀剂,采用共沉淀法制备Cu／Zn／A1／Co催化剂,沉淀时PH值为11,Cu、Zn、AI物质的量之比为9：8：15,加入Co的量为Cu、Zn、Al物质量总和的15％时制备所得的催化剂活性最好;在反应温度400℃,反应压力0．6MPa,乙醇与二氧化碳进料体积比为1：150,乙醇进料速度为0．3mL／min时合成反应最佳,此时乙醇的转化率为53．33％,乙酸乙酯的产率为9．77％,乙酸乙酯的选择性为18．33％。     

单层网壳结构整体稳定性分析

整体稳定性是单层网壳结构设计中的一个关键问题。文章通过对单层网壳结构稳定性理论进行研究,综合现有的网壳稳定性分析方法,按照钢结构设计规范和网壳结构规程的要求,对单层网壳结构进行整体稳定性设计分析。     

四氯化碳加氢Pt／C催化剂活性下降原因浅析

在FYX－1型1L高压反应釜上考察了Pt/C催化剂对四氯化碳加氢制氯仿反应性能的影响，结果表明，CCl4的转化率和CHCl3的选择性均达到95％－97％，但催化剂重复使用后，CCl4转化率明显下降，通过液氮容量吸附和原子吸收光谱法分析，其活性下降的原因可能是反应产生的氯离子与Pt/C催化剂发生了某种化学和物理吸附，氯和Pt形成了Cl-Pt中间体，部分氯占据了Pt/C催化剂的表面，从而导致催化剂活性下降。     

Parallel combinatorial chemical synthesis using single-layer poly(dimethylsiloxane) microfluidic devices

Improving methods for high-throughput combinatorial chemistry has emerged as a major area of research because of the importance of rapidly synthesizing large numbers of chemical compounds for drug discovery and other applications. In this investigation, a novel microfluidic chip for performing parallel combinatorial chemical synthesis was developed. Unlike past microfluidic systems designed for parallel combinatorial chemistry, the chip is a single-layer device made of poly(dimethylsiloxane) that is extremely easy and inexpensive to fabricate. Using the chip, a 2×2 combinatorial series of amide-formation reactions was performed. The results of this combinatorial synthesis indicate that the new device is an effective platform for running parallel organic syntheses at significantly higher throughput than with past methodologies. Additionally, a design algorithm for scaling up the 2×2 combinatorial synthesis chip to address more complex cases was developed.     

负载Cu,Ag氧化物催化剂的氧化活性和热稳定性

考究了Ａｌ２Ｏ３，ＣｅＯ２，ＴｉＯ２负载Ｃｕ，Ａｇ氧化物催化剂的氧化活性及ＣｕＯ／ＣｅＯ２，ＣｕＯ／Ａｌ２Ｏ３催化剂的稳定性。结果表明，载体对催化剂的活性有明显影响，对于ＣＯ氧化，Ｃｕ系催化剂中ＣｕＯ／ＣｅＯ２活性最高，Ａｇ系催化剂中，Ａｇ２Ｏ／Ａｌ２Ｏ３活性最好。     

Ultra-small hollow ternary alloy nanoparticles for efficient hydrogen evolution reaction

Hollow nanoparticles with large specific surface area and high atom utilization are promising catalysts for the hydrogen evolution reaction (HER). We describe herein the design and synthesis of a series of ultra-small hollow ternary alloy nanostructures using a simple one-pot strategy. The same technique was demonstrated for hollow PtNiCu nanoparticles, hollow PtCoCu nanoparticles and hollow CuNiCo nanoparticles. During synthesis, the displacement reaction and oxidative etching played important roles in the formation of hollow structures. Moreover, our hollow PtNiCu and PtCoCu nanoparticles were single crystalline, with an average diameter of 5 nm. Impressively, ultra-small hollow PtNiCu nanoparticles, containing only 10% Pt, exhibited greater electrocatalytic HER activity and stability than a commercial Pt/C catalyst. The overpotential of hollow PtNiCu nanoparticles at 10 mA cm⁻² was 28 mV versus reversible hydrogen electrode (RHE). The mass activity was 4.54 A mg_Pt⁻¹ at −70 mV versus RHE, which is 5.62-fold greater than that of a commercial Pt/C system (0.81 A mg_Pt⁻¹). Through analyses of bonding and antibonding orbital filling, density functional theory calculations demonstrated that the bonding strength of different metals to the hydrogen intermediate (H^*) was in the order of Pt > Co > Ni > Cu. The excellent HER performance of our hollow PtNiCu nanoparticles derives from moderately synergistic interactions between the three metals and H^*. This work demonstrates a new strategy for the design of low-cost and high-activity HER catalysts.     

氧化物催化剂表面过剩氧与氧化活性

本文采用肼法测定了金属氧化物催化剂表面过剩氧的浓度，并考察了吡啶的氧化活性。催化剂的氧化活性与表面氧浓度成正比。氧化活性和表面氧浓度的顺序为：Ｃｕ－Ｏ／Ａｌ＿２Ｏ＿３＞Ｍｎ－Ｏ／Ａｌ＿２Ｏ＿３＞Ｃｒ－Ｏ／Ａｌ＿２Ｏ＿３＞Ｆｅ－Ｏ／Ａｌ＿２Ｏ＿３≥Ｃｏ－Ｏ／Ａｌ＿２Ｏ＿３＞Ｎｉ－Ｏ／Ａｌ＿２Ｏ＿３＞Ｃｅ－Ｏ／Ａｌ＿２Ｏ＿３．随着催化剂焙烧温度的提高，催化剂表面氧浓度和氧化活性均下降。Ｃｕ－Ｏ／ＳｉＯ＿２催化剂中添加ＣｅＯ＿２后，催化剂表面氧浓度和氧化活性均有明显提高，同时催化剂的热稳定性也明显增加。     

Single-atom Sn-Zn pairs in CuO catalyst promote dimethyldichlorosilane synthesis

Single-atom catalysts are of great interest because they can maximize the atom-utilization efficiency and generate unique catalytic properties; however, much attention has been paid to single-site active components, rarely to catalyst promoters. Promoters can significantly affect the activity and selectivity of a catalyst, even at their low concentrations in catalysts. In this work, we designed and synthesized CuO catalysts with atomically dispersed co-promoters of Sn and Zn. When used as the catalyst in the Rochow reaction for the synthesis of dimethyldichlorosilane, this catalyst exhibited much-enhanced activity, selectivity and stability compared with the conventional CuO catalysts with promoters in the form of nanoparticles. Density functional theory calculations demonstrate that single-atomic Sn substitution in the CuO surface can enrich surface Cu vacancies and promote dispersion of Zn to its atomic levels. Sn and Zn single sites as the co-promoters cooperatively generate electronic interaction with the CuO support, which further facilitates the adsorption of the reactant molecules on the surface, thereby leading to the superior catalytic performance.     

盟主权力与能力影响创新联盟稳定性实证研究

以盟主权力和能力为核心,探讨其通过对盟员知识溢出能力与知识吸收能力的相关作用、进而对联盟创新绩效及最终稳定性产生影响的内在机理,并实证检验盟主的契约权力、控制力、影响力和资源配置能力对盟员的知识溢出和吸收能力的积极作用,并促进联盟创新绩效的提升和联盟运行的稳定性。     

如何打造一支素质过硬的学生干部队伍

学生干部队伍是高校学生工作强有力的支撑,辅导员老师应给予高度的重视。对学生干部的产生、辅导员威信的树立、学生干部的培养、学生干部的管理和如何指导学生干部开展工作等都应认真面对,才能真正让广大学生干部通过实践锻炼获得能力,也才能让其真正成为辅导员老师工作的强力助手。     

An artificial chromosome for data storage

DNA digital storage provides an alternative for information storage with high density and long-term stability. Here, we report the de novo design and synthesis of an artificial chromosome that encodes two pictures and a video clip. The encoding paradigm utilizing the superposition of sparsified error correction codewords and pseudo-random sequences tolerates base insertions/deletions and is well suited to error-prone nanopore sequencing for data retrieval. The entire 254 kb sequence was 95.27% occupied by encoded data. The Transformation-Associated Recombination method was used in the construction of this chromosome from DNA fragments and necessary autonomous replication sequences. The stability was demonstrated by transmitting the data-carrying chromosome to the 100th generation. This study demonstrates a data storage method using encoded artificial chromosomes via in vivo assembly for write-once and stable replication for multiple retrievals, similar to a compact disc, with potential in economically massive data distribution.     

旅游活动对溶洞碳酸钙沉积景观影响及保护性研究

随着旅游业发展,越来越多的溶洞旅游资源在我国被开发,其中的碳酸钙沉积景观是主要的旅游吸引物之一,由于其形成环境比较封闭,随着开放时间的推移,都不同程度出现了风化、破损现象,因此溶洞景区一般被视为生命周期较短。为了实现旅游资源的可持续发展,在溶洞旅游资源开发的过程中体现“在保护中开发,在开发中保护”的理念,本文从碳酸钙沉积景观形成的水文地球化学过程入手,通过分析洞穴水溶液中CO₂溶解度影响因子,即水溶液温度和水溶液与洞穴环境之间的CO₂分压差(ΔPCO₂),从旅游活动的影响角度,对游客的热源与CO₂源效应进行分析,提出了基于游客影响和景观形成过程研究的措施,即采用分流游客和水文地球化学实验方法进行景观保育以及科学的开发管理作为旅游溶洞碳酸钙沉积景观保护的有效措施。     

基于灰色证据理论的专利质量综合评价

[目的/意义]科技创新处于国家发展全局的核心位置,专利保护作为其重要的一环,越来越受到大众重视.如何精准地进行专利质量评估,对促进经济发展、技术进步、社会资源的优化配置等具有重要作用.[方法/过程]基于现有专利质量评估的相关研究,从专利技术价值、法律价值和经济价值三个方面,建立了量子遗传算法结合层次分析理论的专利质量评...     

随机风荷载下单层球面网壳的整体疲劳分析

对随机风荷载下K6型单层球面网壳的整体疲劳问题进行了研究。用AR法模拟Kaimal谱多点互相关的脉动风风速时程,确定结构所承受的荷载谱,通过有限元时程分析和雨流计数法得到杆件的应力循环历史,采用疲劳设计方法中的总寿命法计算杆件的疲劳损伤度,分析结构在不同矢跨比、不同平均风速下结构的抗疲劳性能。研究发现,结构中出现疲劳的杆件数随矢跨比的减小而逐渐增加,结构中杆件最大疲劳损伤度D随着矢跨比的减小而逐渐增大。网壳的疲劳薄弱区域主要与结构的振型有关;矢跨比较大时,结构中环向杆件易出现疲劳,随着矢跨比的减小,结构径向肋两侧的斜杆易出现疲劳。     

图书馆公共关系职能研究

作为协调社会关系的重要管理机制,公共关系通过其职能的运用,化解矛盾、对立和冲突,维护社会和公众利益,对各种错综复杂的社会关系加以全面有效的调整,为组织创造适合其生存、发展的社会环境,使整个社会形成和谐安定的良好秩序.     

图书管理系统的系统分析及数据库设计

计算机软件作为现代图书馆发展的重要组成部分,具有手工管理所无法比拟的优点。例如,检索迅速、查找方便、存储量大、可靠性高、寿命长、成本低等。这些优点能够极大地提高图书管理的效率,也是图书管理规范化、信息化、数字化的必然趋势,以及为与国内外图书馆接轨提供了重要条件。本文重点对有关图书馆图书管理系统的相关使用功能需求进行介绍,并在此基础上提出数据库设计方案,并对此方案进行改进,弥补了之前相关数据库设计的不足。