骨质瓷用合成骨炭的研制

采用固相合成法,用廉价的碳酸钙和磷酸氢钙等作原料,在特定温度条件下进行固相合成反应,可以得到一种用于生产陶瓷用品的粉末状合成骨炭,其主要成分是羟基磷酸钙。将合成得到的骨炭产品按照骨质瓷器的烧制条件,进行了烧制骨质瓷的实验验证,实验结果表明所研制的合成骨炭,不仅能满足骨质瓷器生产的质量要求,同时合成骨炭的价格低廉、生产过程清洁环保,合成骨炭产品的成本比天然骨炭的成本低40%左右。     

三模板剂法合成钛硅介孔纳米球

以十二烷基硫酸钠(DDS)、十六烷基三甲基溴化铵(CTAB)、聚丙烯-聚乙烯-聚丙烯三嵌段共聚物(P123)为模板剂,以硫酸钛和偏硅酸钠为金属源,使用三模板剂法首次合成出钛硅介孔纳米球材料。用XRD,ICP,HRTEM,SEM,FTIR和低温氮吸附等多种手段对材料进行了表征。结果表明,所制备的钛-硅材料是介孔纳米球结构,球径约为2 000 nm。当n(钛)/n(硅)增加时,介孔孔径增大,比表面积降低。     

探讨有机催化的不对称Michael加成反应

在现今的科研领域中,针对有机催化的不对称合成反应是主要的研究热点,不对称Michele加成反应是大量手性合成子以及药物中间体的合成的重要方式。现今已有催化Michale加成反应的有机催化剂主要有脯氨酸及其衍生物、手性咪唑啉酮以及金鸡纳碱衍生物等。文章对多种有机催化剂在催化不对称Michael加成反应中的使用、不对称诱导反应的作用机制、催化剂分子结构、作用反应条件对催化活性以及不对称诱导作用的影响等方面进行了综述,期望为后续研究带来一定的参考。     

对硝基苯乙腈的制备

对硝基苯乙腈是合成药物的重要中间体。也用于制备液晶及农用化学品。它的制备方法有两种：一是苯乙腈直接和混酸（浓HNO3或H2SO4）反应，对硝基苯乙腈收率为48%，二是对硝基苄基卤和NaCN反应，用DMSO为溶剂，并在反应混合物中加入一定量的浓H2SO4，产品收率为40%，现介绍用浓HNO3和多聚磷酸作硝化剂，定向硝化苯乙腈制备对硝基苯乙腈的方法，15g质量分数为96%的苯乙腈滴加到27.5mL质量分数为68%的HNO3和多聚磷酸混合物中，在20～25℃下反应2h，反应产物用乙醇水溶液重结晶得对硝基苯乙腈12.9g，产品的收率为64.29%，ω（对硝基苯乙腈）=99.11%。     

TiO2/SiO2催化酯交换合成草酸二苯酯

使用负载型TiO2/SiO2催化剂催化了草酸二乙酯和苯酚酯交换反应合成草酸二苯酯。采用NH3-TPD探讨了催化剂表面酸性强弱对草酸二乙酯和苯酚酯交换反应的影响。结果表明,催化性能与TiO2/SiO2催化剂上存在的酸中心强度密切相关,弱酸中心的存在导致了催化剂良好的催化活性。同时考察了不同反应温度、回流温度、原料物质的量比和反应时间等对反应性能的影响。当TiO2负载量为10%(质量分数)时,TiO2/SiO2的催化性能最佳,草酸二乙酯的转化率为49.5%,草酸二苯酯的收率为11.8%,乙基苯基草酸酯的收率为37.7%,目的产物草酸二苯酯和乙基苯基草酸酯的总选择性为100%。     

复合模板剂合成SBA-15介孔分子筛的结构表征及机理研究

采用复合模板剂P123及Tritonx-100合成新型SBA-15介孔分子筛,分别利用N2等温吸附、X射线衍射及透射电镜对样品进行表征。介孔分子筛比表面积可达600 m2/g,单位质量的孔容积大于1 mL/g,平均孔径为7~8 nm,孔径分布窄,孔道长程有序,结晶度较高。通过与单一模板剂合成样品的比较可知,辅助模板剂Tritonx-100能有效地改善孔径分布及孔道排列,通过实验找出了最佳模板剂配比为n(Tritonx-100)∶n(P123)=4∶1。     

PEG 致孔的快速响应敏感水凝胶的制备及其响应性能

以PEG作为致孔剂,制备了具有快速响应性的温度敏感及pH敏感的聚N,N’-二乙基丙烯酰胺-co-海藻酸钠P（DEAA-co-SA）水凝胶,研究了致孔剂用量及不同单体配比对凝胶温度敏感性及pH敏感性的影响。结果表明,DEAA是一种温敏性单体,其在凝胶中的含量越高,凝胶的温度敏感性越强;而随着共聚凝胶中SA组分的增加以及致孔剂用量的增大,凝胶表现出较强的pH敏感性。     

组织工程用三维多孔支架制备技术研究进展

综述了近几年组织工程用三维多孔支架的制备技术及研究成果,传统技术包含微球烧结法、溶液浇铸/粒子沥滤法、热致相分离/冷冻干燥法、静电纺丝法、快速成型法等;超临界技术包括超临界CO2发泡法、超临界CO2乳剂制模法、超临界CO2静电纺丝法、超临界辅助相分离法、超临界CO2溶剂去除法、离子液体聚合物混合干燥法等。重点评述了超临界流体技术在组织工程用三维支架制备中的发展前景。     

碳载铂催化剂的两种制备方法

采用羟基铂酸为前驱体,通过沉淀转化工艺制备了铂担载量为20%(质量分数)的碳载铂催化剂。通过该方法制备得到的催化剂中纳米铂颗粒的粒度细小均一(约2~9 nm)、在载体上分布均匀、杂质Cl-含量少。质子交换膜燃料电池(PEMFC)单电池测试表明,该方法制备的催化剂对H2氧化的催化性能与E-TEK商品催化剂相当,最高输出功率密度达到1.34W/cm2。     

银/聚酰亚胺复合光催化剂的制备与性能

为了拓宽聚酰亚胺(PI)基光催化剂的应用范围,并提高催化性能,将纳米银(AgNPs)与PI复合,成功制备了Ag/PI复合光催化剂。通过原位热处理法和离子交换法制备Ag/PI光催化剂,以对硝基苯酚(4-NP)的还原为模型反应,考察其光催化性能。采用FT-IR,XRD,TEM,Mapping,XPS,UV-Vis DRS,PL和EIS等手段分析了Ag/PI光催化剂的结构、组成和光电性质。结果表明,Ag的掺杂大大提高了PI的光吸收能力、光响应范围和光生电子-空穴对的分离效率,Ag/PI光催化剂对4-NP还原反应有较高的催化活性,催化效率远远高于Ag与其他物质复合的催化体系。当采用离子交换法,Ag质量分数为0.5%时,Ag/PI光催化剂的光催化性能最好。Ag/PI光催化剂具有良好的稳定性和可重复使用性。研究提供了一种简便制备PI基高效复合光催化剂的方法。     

数字多用表蜂鸣器电路的设计

压电陶瓷是一种具有压电效应的高灵敏度、微功耗电声器件。首先介绍压电陶瓷蜂鸣器的技术特性 ,然后重点阐述数字多用表蜂鸣器电路的设计 ,包括适配 ICL71 0 6型 3 位单片 A/D转换器、ICL 71 2 9型 4 位单片 A/D转换器的两种蜂鸣器电路的设计。     

Positioning through B2B carrier signals: Understanding how service quality is communicated via websites

Today's marketplace requires B2B motor carriers to connect with shippers in salient ways. To accomplish this, B2B carriers communicate signals of service quality in order to position themselves uniquely from the competition. Signaling theory describes how inequity in information between parties is filled by sending signals to convey missing information (Spence, 1973). Signaling theory was used as a foundation to investigate information used by B2B carriers to signal service quality and create positioning strategies. Results of a content analysis of 490 B2B motor carrier websites for signals of 12 dimensions of service quality are used to develop a typology of U.S. B2B motor carriers. These are: Minimalist, User-Friendly, and Safety First. Associations with firm revenues, firm size, credit score, and number of NAICS codes used are discussed along with implications.     

Quality-Adjusted Prices of Japanese Mobile Phone Handsets and Carriers’ Strategies

In order to discuss oligopolists’ strategic determination of quality-adjusted prices (QAPs), we conducted a hedonic regression analysis using adjacent periods and estimated the QAPs of mobile phone handsets sold in Japan between 2002 and mid-2007 for each carrier. We observed (1) a decreasing trend in QAP for each carrier, (2) a more rapid decrease in the QAPs of the two smaller carriers’ handsets relative to that of the largest carrier, and (3) a turnover cycle of the QAPs between the two smaller carriers. If both small carriers decrease their QAPs at roughly the same time, neither will significantly increase their subscriber share, which can generate a turnover cycle of QAPs.     

高阻隔陶瓷薄膜包装材料的研究进展及关键技术

本文总结了高阻隔陶瓷薄膜包装材料制造技术的发展进程,介绍了各种镀膜方法及特点;系统综述了国内外AlOx、SiOx薄膜的研究进展与应用现状,分析了陶瓷薄膜包装材料制造过程中影响阻隔性能的主要因素,研究了提高薄膜阻隔性的基本措施,由此展望了高阻隔陶瓷薄膜包装材料发展及应用前景。     

陶瓷膜污染与清洗

陶瓷膜是一种新型材料的膜,其在使用过程中会产生污染和堵塞,使膜渗透通量逐渐下降,尤其是应用于污水处理过程中的陶瓷膜,污堵随时发生。总结了陶瓷膜的性质、膜污染及其防治措施,综述了陶瓷膜清洗技术的研究进展,对陶瓷膜未来的发展进行了展望。     

The mixed blessing of a deregulatory endpoint for the public switched telephone network

Receiving authority to dismantle the wireline public switched telephone network (PSTN) will deliver a mixture of financial benefits and costs to incumbent carriers and also jeopardize longstanding legislative and regulatory goals seeking ubiquitous, affordable and fully interconnected networks. Even if incumbent carriers continue to provide basic telephone services via wireless facilities, they will benefit from substantial relaxation of common carriage duties, no longer having to serve as the carrier of last resort and having the opportunity to decide whether and where to provide service. On the other hand, incumbent carriers may have underestimated the substantial financial and marketplace advantages they also will likely lose in the deregulatory process. Legislators and policy makers also may have underestimated the impact of no longer having the ability to impose common carrier mandates that require carriers to interconnect so that end users have complete access to network services regardless of location.This paper will identify the potential problems resulting from prospective decisions by National Regulatory Authorities (NRAs), such as the United States Federal Communications Commission (FCC), to grant authority for telecommunications service providers to discontinue PSTN services. The paper also will consider whether in the absence of common carrier duties, private carriers providing telephone services, including Voice over the Internet Protocol (VoIP), voluntarily will agree to interconnect their networks. The paper will examine three recent carrier interconnection issues with an eye toward assessing whether a largely unregulated marketplace will create incentives for carriers to interconnect networks so that consumers will have ubiquitous access to PSTN replacement and other broadband services.The paper concludes that private carrier interconnection models and information service regulatory oversight may not solve all disputes, or promote universal service public policy goals. Recent Internet interconnection and television program carriage disputes involving major players such as Comcast, Level 3, Fox, Cablevision and Google point to the possibility of increasingly contentious negotiations that could result in balkanized telecommunications networks with at least temporary blockages to desired content and services by some consumers.     

等离子喷涂梯度耐热陶瓷涂层的研究展望

主要概述了耐热梯度陶瓷涂层的研究现状 ,阐述了耐热梯度陶瓷涂层的制备、组织和性能研究的成果和存在的问题 ,并提出了耐热梯度陶瓷涂层发展的新方向     

The Determinants of Pricing in the Mexican Domestic Airline Sector: The Impact of Competition and Airport Congestion

Low-cost airlines in Mexico affect the lowest-quoted fares of one of the two principal incumbent carriers, but have no effect on the lowest-quoted fares of the other incumbent carrier. The same conclusion holds for competition between incumbent carriers where the lowest-quoted fares of one of the incumbent carriers is lower when incumbents compete. Congestion at the Mexico City airport is limiting potential competition, with carriers being able to charge a significant price premium. This suggests that the societal costs of airport congestion can go well beyond the negative congestion externality and should also include the effects of reduced competition. These findings raise important public policy issues.     

Australian consumer attitudes to health claim – food product compatibility for functional foods

This study with Australian consumers investigated how appealing different health claims combined with particular food carriers were to Australian consumers, and compared the results of a similar study with Dutch consumers. 149 shoppers considered up to 30 different food concepts, rating how ‘attractive’, ‘believable’, and ‘new and different’ they found each concept and their ‘intention to try’. Each variable was significantly related to intention to try (p < 0.001) and together explained 56% of the intention score. Claims and carriers independently had a significant effect on ratings of attractiveness and intention to try but, unlike the Dutch study, the carrier was a more important predictor of intention to purchase than the claim. Implications for regulation of health claims for food are discussed.     

Vertical Integration in International Telecommunication System

The process of liberalization and privatization is drastically altering the links among international telecommunications carriers. The model presented in this paper analyses the international telecommunications market illustrating the effects of vertical mergers, under symbiotic production conditions, when vertically integrated and unintegrated carriers coexist. The effect of competition is analysed both in the final market and in the intermediate one where carriers compete over tariffs to get an appropriate distribution of profits. In particular, the results show the relations between final market prices, intermediate tariffs and market dimensions and their implications on profits.