Au@Cu_2O核壳纳米颗粒的可控制备及其光学性能研究

采用液相还原法,快速、高效地制备了金@氧化亚铜(Au@Cu_2O)核壳复合纳米颗粒。通过改变实验参数,实现了Au@Cu_2O核壳复合纳米粒子尺寸的精确控制。利用紫外-可见-近红外分光光度计测试其光学性质,结果表明,该复合纳米粒子的表面等离子共振(SPR)吸收峰随着Cu_2O壳层厚度的增加发生红移,且吸收强度逐渐增强。     

共振瑞利散射光谱法测定氯硝柳胺的研究

在PH=1.65的BR缓冲溶液中,十六烷基三甲基溴化铵和氯硝柳胺本身的共振瑞利散射（RRS）均很微弱。但两者相互作用形成离子缔合物时,溶液的RRS显著增强,并产生了新的RRS光谱,其RRS峰位于385nm。在一定条件下氯硝柳胺的浓度与散射强度成正比,据此建立了测定微量氯硝柳胺的瑞利散射光谱分析法。该方法灵敏度高,其检出限为0.0576μmol/L。用于氯硝柳胺的测定,具有操作简便、快速、灵敏、选择性好等特点。     

一种基于适配体传感器的17β-雌二醇定量分析方法

为了灵敏、特异地测定牛奶中17β-雌二醇(E2)的含量,解决传统方法测定时因原位激发导致的荧光背景干扰、样品预处理复杂等问题,基于荧光共振能量转移(FRET)原理,结合适配体与靶标的特异性识别,建立一种基于荧光适配体传感器的E2定量分析方法。采用水热合成法制备铕(Eu~(3+))掺杂的镓酸锌长余辉纳米粒子,并将E2适配体修饰到纳米粒子(PLNP)上,形成复合物(PLNP-Aptamer)。以PLNP-Aptamer为能量供体,以二硫化钼纳米片为能量受体,根据荧光强度与靶标17β-雌二醇之间的线性关系实现对E2的检测,并对检测条件进行优化。结果表明,当PLNP-Aptamer、二硫化钼的质量浓度分别为0.1,0.8 mg/mL,E2与适配体的孵育时间为20 min, pH值为7.0时,雌二醇的线性检测范围为0.6～80 ng/mL,检出限为0.4 ng/mL。通过加标回收实验,证明检测体系对17β-雌二醇具有显著的选择性,可用于实际样品的检测。所提方法解决了样品预处理复杂耗时,乳基质荧光干扰等问题,可为基层卫生监督工作提供一种简单、高效、成本低廉的雌激素检测方法,对其他环境雌激素的检测也具有参考价值和借鉴意义。     

微反应器制备纳米氢氧化镍的研究

以乙酸镍溶液和氢氧化钾溶液为原料,采用微反应器技术对制备纳米氢氧化镍进行了研究,实验中考察了反应物浓度、流速和反应温度对纳米氢氧化镍颗粒粒径的影响,并通过ZetasizerNano-ZS90激光粒度测定仪、D/MAX-2500X型XRD和SEM-4800-I型场发射扫描电镜分别对产品进行了表征。结果表明,制得的纳米氢氧化镍的粒径分布较窄,且平均粒径随反应物浓度提高而增大,随流速增大而减小,随反应温度的升高而增大。在室温条件下,乙酸镍溶液浓度为0.2mol/L,流速为8.68m/s时制得了近似球形形状、平均粒径为29nm,粒度分布窄的氢氧化镍纳米颗粒。     

纳米球形二氧化硅的制备工艺研究

本文主要研究以廉价的水玻璃为主要原料,采用化学共沉淀法制备纳米二氧化硅,添加一定量的表面活性剂,进行沉淀反应,通过检测手段对其表征,得到纳米二氧化硅。结果显示本方法所制得的二氧化硅粉体为近球形,其平均颗粒直径为100nm,平均表面积为1148.9m2/g。在实验过程中,本文对影响前驱物形成的主要因素做了研究分析,包括原料水玻璃的杂质、模数、浓度和反应的pH值、反应温度、表面活性剂、陈化时间及烘干和焙烧的方式的影响做了研究分析,寻找到了最佳的反应条件。     

基于金纳米簇的荧光传感器检测水体中的汞离子

以鸡蛋清蛋白为还原剂和稳定剂合成了荧光金纳米簇,研究了汞离子对金纳米簇的荧光猝灭效应,确定了水体中汞离子的最佳检测条件。基于最佳实验条件,当水体中汞离子浓度在0.05～6μg/g时,合成的金纳米簇荧光猝灭程度与汞离子浓度呈良好线性关系,回归方程为:F0/F=0.06810C+1.0041,线性相关系数为0.9989。对某河流样品进行了应用分析,取五个不同河段区域的样品并对每个样品重复测试五次,其标准偏差小于3.5%,检出限为0.01g/g,其应用分析加标回收率为96%～105%。     

HPLC法测定注射用甲磺酸左氧氟沙星有关物质

建立了注射用甲磺酸左氧氟沙星有关物质的HPLC测定方法,色谱柱为C18柱(4.6 mm×200 mm,5μm),以己烷磺酸钠溶液-甲醇为流动相,流速为1.0 mL/min,检测波长为293 nm,最低检测量为5.29 ng/mL,本法专属性强、准确、精密、灵敏,适用于该制剂有关物质的测定。     

HPLC法同时测定薄荷配方颗粒中6种成分的含量

为了提高薄荷配方颗粒的质量标准,建立其多指标定量评价体系,采用HPLC法同时测定薄荷配方颗粒中咖啡酸、橙皮苷、迷迭香酸、香叶木苷、香蜂草苷和蒙花苷6种成分的含量。采用Poroshell 120 EC-C_(18)(4.6 mm×250 mm, 5μm)色谱柱,以甲醇(A)-乙腈(B)-5%冰乙酸(C)为流动相,梯度洗脱,流速为0.6 mL/min,柱温为35℃,咖啡酸、迷迭香酸、蒙花苷的检测波长为330 nm,橙皮苷、香蜂草苷的检测波长为284 nm,香叶木苷的检测波长为380 nm。结果表明,薄荷配方颗粒中6种待测成分的线性关系、分离度、重复性均符合要求,各成分的平均回收率分别为99.19%,98.06%,100.45%,98.90%,100.17%,99.78%。不同厂家的薄荷配方颗粒中6种化学成分的含量存在一定差异。建立的HPLC分析方法简便、快速、准确,可以为薄荷配方颗粒的质量控制提供方法参考。     

食品中微量金属元素的微波消解——电感耦合等离子体质谱半定量法分析

结合当前中国食品微量元素的检测方法来看,主要应用到的快速检测方法有微波消解-电感耦合等离子体质谱半定量法,此方法通常用于测量食品中的Cu、Pb、Hg、Sb、Cr等微量元素。文章通过实验的方式来求证食品中微量金属元素的微波消解-电感耦合等离子体质谱半定量法,通过实验分析结果显示,此方法测量结果较为准确,可实现对食品中微量元素的快速检测。     

小样品量比色管过硫酸钾消解法测定总磷的研究

针对标准过硫酸钾消解测定总磷采用50mL比色管、耗时长且消耗大量实验药品的问题,提出了用25mL比色管进行消解测定。通过空白值、重现性、相关系数及加标回收率几方面与标准方法进行比较,25mL比色管测得的标准曲线y=1.5173x+1.20×10-3,相关系数为0.9998,加标回收率在98.4%～104.1%之间,与标准方法使用的50mL比色管测得的值无显著性差异。实验表明该法简便快速、节约成本、准确可靠。     

Comparing FTTH access networks based on P2P and PMP fibre topologies

There is an ongoing discussion in the market which Next Generation Access (NGA) architecture best suits future needs and which investment and cost differences exist. The discussion can be subsumed as P2P vs. GPON, which is somewhat misleading as this article reveals. The discussion is driven by the fact that the high capital cost and the long asset life time of fibre mean that the technology choices made today will dominate the opportunities for telecommunication business of all market players, incumbents, competitors, content providers and business and residential users for many years in the future.The paper analyzes the cost and other differences between Fibre-to-the-Home (FTTH) access network architectures and their related different wholesale approaches by using the well-known and understood steady state approach applied in other NGA analyses in the past. In addition to the steady state analysis a dynamic cost evaluation is included taking into account the different investment behaviour of the FTTH architectures over time. The results describe investment and cost differences between architectures, incumbents and wholesale based competitive operators. The analysis has been performed for different geotypes (clusters) of decreasing population density in a representative European settlement structure.     

Indigenous peoples’ nutrition transition in a right to food perspective

In indigenous communities the nutrition transition characterized by a rapid westernization of diet and lifestyle is associated with rising prevalence of chronic disease. Field work and literature reviews from two different policy environments, Argentina (Jujuy) and Canada (Nunavut), identified factors that add to indigenous peoples’ disease risk. The analytical framework was the emerging human right to adequate food approach to policies and programmes. Indigenous peoples’ chronic disease risk tends to increase as a result of government policies that infringe on indigenous peoples’ livelihoods and territories, undermining their economic system, values and solidarity networks. Policies intended to increase food security, including food aid, may also fuel the nutrition transition. There is a need to explore further the connection between well-intended policies towards indigenous peoples and the development of chronic diseases, and to broaden the understanding of the role that different forms of discrimination play in the westernization of their lifestyles, values and food habits. Food policies that take due account of indigenous peoples’ human rights, including their right to enjoy their culture, may counteract the growth of chronic disease in these communities.     

A strategic skill based model of supplier integration and its effect on supply management performance

Supplier integration is a tool to help organizations gain competitive advantage. Strategic supply management skills and the supply management function's perceived status are hypothesized as antecedents to supplier integration leading to supply management performance. The sample for this study includes 152 executive level supply management professionals. The empirical results suggest that strategic skills and perceived status are essential antecedents to supplier integration and subsequent performance. Further, the relationship between strategic skills and performance is mediated by supplier integration. Results of a dominance analysis also suggest which strategic skills are most likely to explain status integration, and performance. These findings have significant implications for supply management theory and practice.     

Collectivism,individualism, and outgroup cooperation in a segmented China

A consistent theme in cross-cultural management research is that collectivists are more cooperative than individualists. We use Hofstede's measure for individualism–collectivism and combine it with an experimental measure of cooperation to test this relationship in China. In contrast to the established paradigm, we find that groups with higher individualistic scores are more cooperative than those groups with higher collectivistic scores. We attribute these results to groups being composed of outgroup members. In addition, we find that subjects from the more developed coastal area are more individualistic and cooperative than are subjects from inland China.

Cost allocation of WCDMA and wholesale pricing for mVoIP and data services

This study estimates cost-based prices for wholesale voice and data services provided to 3G (WCDMA) MVNOs according to their distinct types. For estimation, 3G MVNOs are classified into different types, and the overall cost of WCDMA facilities are separated into voice and data components based on their subscriber rates, actual traffic rates, as well as efficiency consideration of traffic rates. The study then calculates cost-based wholesale prices of voice and data services for each of the 3G MVNO types. The result of this study shows that a cost-plus pricing scheme can help achieve the policy goals of the regulator, namely, lowering telecommunications tariffs and facilitating the introduction of new convergent-type services, far more effectively than the current retail-minus pricing scheme. The findings of this study may assist firms in developing business models based on 3G networks and telecom regulators in designing policies related to interconnection, mVoIP, prepaid calls, wholesale services, and network neutrality.     

电子产品的电磁兼容性设计

首先介绍电磁兼容性的基本概念与研究领域,然后重点阐述电子产品的电磁兼容性设计与测量。     

SPYRO在烯烃原料生产方案测算中的应用

文章对SPYRO裂解模拟软件在石化企业烯烃生产原料优化方案测算中的应用进行了比较深度的概括分析.结合该软件在上海石化的实际应用,认为在劣质化原油加工份额不断增加的趋势下,SPYRO裂解模拟软件有助于石化企业在烯烃生产原料优化选择、生产计划合理安排、原油加工生产效益比较等方面为企业相关决策者提供有效地帮助.     

施工企业工程项目部的建设浅论

工程项目的一次性决定了工程项目部的一次性，而工程项目成本中心与企业利润中心地位又辱致工程项目部的临时性，在工程项目实践过程中，项目经理部的一次性在实现其功能的过程中可能会产生很多局限和负面影响，故项目部应具有相对的稳定性，在此基础上，本对工程项目部建设实践进行了初步总结并提出了建议。     

面向对象的程序设计

用Ｃ＋ ＋ 语言阐述面向对象程序设计中封装和继承的概念以及在实际中怎样运用这些概念提高程序设计水平。     

European consumer preferences for beef with nutrition and health claims: A multi-country investigation using discrete choice experiments

The European Union (EU) nutrition labelling policy aims to facilitate consumers’ food choice, stimulate innovation and facilitate the circulation of foods bearing claims across countries. However, the beef industry has not fully taken advantage of utilizing nutrition and health claims based on the EU nutrition labelling policy to differentiate beef products in the market. This study investigates consumer preferences for nutrition and health claims on lean beef steak. Two choice experiments were conducted among 2400 beef consumers in four EU countries (Belgium, France, the Netherlands, United and United Kingdom). Multinomial logit and error component models were estimated. Our results generally suggest that consumer valuation of nutritional and health claims varies across countries. In Belgium, the Netherlands and France, nutrition and health claims on saturated fat yielded higher utilities than claims on protein and/or iron, while the opposite was found among consumers in the UK. The results imply that marketing opportunities related to nutrition and health claims on beef are promising, but that different nutritional marketing strategies are necessary within different countries.