光纤通信的过去、现在和未来

简略介绍了世界光纤通信发展历史,概括了光纤通信的现状,最后重点介绍了中国光纤通信的发展历程。     

纳米材料在蛋白磷酸化分析中的应用研究

蛋白质磷酸化修饰是一种重要的蛋白质翻译后修饰,在细胞代谢过程中发挥着重要作用。当蛋白质的正常磷酸化调节发生异常时,会导致癌症、糖尿病、心脏病等各种疾病的发生。因此,蛋白磷酸化分析对于疾病的早期快速诊断、药物筛选和治疗等方面具有重大的意义。由于蛋白质磷酸化过程是动态的,并且磷酸化肽段或蛋白在生物样品中的含量较低,因此高灵敏的蛋白磷酸化分析面临着巨大的挑战。该文依据在检测过程中,选择性识别或捕获磷酸化的肽段或蛋白的主要机理,综述了近几年纳米材料对磷酸化肽段的富集和信号放大作用在蛋白磷酸化分析中的研究进展,并对其未来研究方向进行了展望。     

Structure of tecophilin,a tri-caffeoylanthocyanin from the blue petals of Tecophilaea cyanocrocus, and the mechanism of blue color development

The pigment, tecophilin, in blue flowers of Tecophilaea cyanocrocus was isolated and the structure was determined to be 3-O-(6-O-α-l-rhamnopyranosyl-β-d-glucopyranosyl)-7-O-(6-O-(4-O-(2-O-(4-O-β-d-glucopyranosyl-(E)-caffeoyl)-6-O-(4-O-β-d-glucopyranosyl-(E)-caffeoyl)-β-d-glucopyranosyl)-(E)-caffeoyl)-β-d-glucopyranosyl)delphinidin. The reproduction experiment of the same color as petals according to the results of chemical analysis and measurement of vacuolar pH of blue cells clarified that the blue color solely develops by tecophilin without interaction of metal ions nor co-pigments. ¹H NMR analysis and CD spectrum indicate the co-existence of clockwise intermolecular self-association of the delphinidin nuclei and intramolecular π–π stacking between the chromophore and caffeoyl residues to derive bathochromic shift of the absorption spectrum and stabilize the color by preventing hydration reaction.     

Microwave assisted fluorination: an improved method for side chain fluorination of substituted 1-arylethanones

A two-step, one-pot microwave (MW) assisted fluorination of 1-arylethanones to their corresponding 1-aryl-2-fluoroethanones has been developed. The first step utilises Selectfluor™ as a fluorinating agent in methanol forming 1-aryl-2-fluoroethanones and their corresponding dimethyl acetals. In the second step, water is added and Selectfluor™ acts as a Lewis acid in the hydrolytic cleavage of the dimethyl acetals. Compared to the thermal synthesis, the MW assisted method leads to a reduction in reaction time both in the fluorination and for the dimethyl acetal cleavage. Moreover, the one-pot procedure reduces reagent and solvent consumption. The method is best suited for the preparation of 1-aryl-2-fluoroethanones containing substituents that deactivates electrophilic aromatic substitution, however highly electron deficient ketones such as 1-(3,5-dinitrophenyl)ethanone reacts more slowly. Reactions using electron rich aromatic ketones had a low regioselectivity, and also produced fluoroaromatic products.     

Product concept and prototype flexibility in manufacturing: Implications for customer satisfaction

A rapidly changing competitive landscape and dynamic customer expectations require manufacturing firms to seek flexibility in product development. Product concept flexibility (i.e., developing design options) and product prototype flexibility (i.e., creating working models) emerge as effective ways to quickly develop new products that meet competitive challenges and satisfy customer demands. Product concept flexibility enables firms to fully explore various product definitions and ideas. Product prototype flexibility allows firms to gather customers’ feedback and investigate design feasibility. Using data from 273 manufacturing firms, this research tests mediating, moderating, and additive models that relate product concept flexibility, product prototype flexibility, and customer satisfaction. The results indicate that firms with high product concept flexibility are more likely to benefit from prototype flexibility than firms with low product concept flexibility, and that product concept flexibility and product prototype flexibility act independently and additively to predict customer satisfaction.     

基于AHP和DEA联用的城市交通环境可持续发展评价方法研究

将层次分析法(AHP)和数据包络分析(DEA)相结合构建了两种方法的联用评价模式,对使用该方法评价城市交通环境可持续发展水平和后续决策指导方面进行了探讨.该方法对AHP法在多个决策单元定量对比分析和DEA体现决策者偏好方面进行了改善.从影响城市交通环境可持续发展水平的城市综合发展、道路设施水平、交通运输功能和交通环境质量等方面出发,建立了城市交通环境可持续发展评价体系,并应用于深圳市实证分析,通过AHP分析认为深圳市2000～2007年城市交通环境可持续发展水平在波动中缓慢上升,再通过27个城市2005年数据DEA有效性分析和投影分析,得到深圳市在城市交通环境可持续发展方面的总体效率为0.9729,并得到了其要达到DEA有效的调整方案和部分政策建议.     

On a class of singular stochastic control problems driven by Lévy noise

A class of singular stochastic control problems whose value functions satisfy an invariance property was studied by Lasry and Lions (2000). They have shown that, within this class, any singular control problem is equivalent to the corresponding standard stochastic control problem. The equivalence is in the sense that their value functions are equal. In this work, we clarify their idea and extend their work to allow Lévy type noise. In addition, for the purpose of application, we apply our result to an optimal trade execution problem studied by Lasry and Lions (2007).     

Supporting disciplinary and interdisciplinary knowledge development and design thinking in an informal,pre‐engineering program: A Workplace Simulation Project

In this paper, we examined students’ engagement in an implementation of a Workplace Simulation Project (WSP). The WSP was designed to actively engage students in learning disciplinary content by inviting engineers from industry to have a physical presence within the school building to collaborate with teachers and students to complete projects which simulate the tasks authentic to their work. We focus on the first year implementation of the program that partnered a high school in the rural Midwest with an engineering unit of a government organization. Using a multiple methods study design, we analyzed disciplinary and interdisciplinary pre and posts test along with students’ interviews to determine learning gains as well as students’ interpretations of creative and critical thinking as experienced in the project and their knowledge of the engineering design process. Effect sizes showed that students in the WSP group had notable gains over the control group participants. Additionally, students’ knowledge of core elements of the design process were identified in inductive analyses of the interviews. Findings from this study will provide usable knowledge about effective ways to support systems and design thinking and ways to support expert‐novice collaboration to ensure success.     

二次注射成型聚丙烯中剪切诱导连接界面的形态演变

研究了剪切作用对二次注射成型聚丙烯连接界面形态演变的影响.利用偏光显微镜研究了连接界面距离浇口不同区域和不同位置的形态差异,探索了连接界面形态的演变规律,通过改变注射压力和注射速度对其加以验证,并通过DSC分析证实了形态结构的差异.研究表明:剪切作用对连接界面形态的影响显著,在高剪切作用下分子链沿流动方向取向程度高,不利于其规整排列并沿垂直界面方向生成横晶;可以通过注射压力和注射速度来控制连接界面的剪切作用,从而得到具有完善横晶结构的连接界面形态.     

子宫内低铅暴露对婴儿早期神经行为影响的研究

为探讨低铅暴露对婴儿智能发育的影响,随机选择足月顺产新生儿110例,0.48 μmol/L＞脐血铅水平≥0.24 μmol/L,作为观察组;同一时期配对足月顺产新生儿110例,脐血铅水平＜0.24 μmol/L,作为对照组;采用新生儿20项新生儿神经行为、Gesell婴幼儿发育检查量表,在出生24～36 h和3月龄时进行测试.结果表明,观察组神经行为总得分显著性低于对照组;头竖立得分显著低于对照组,头竖立时间较对照组缩短;3月龄观察组适应性、语言能力和个人社会交往显著低于对照组. 提示血铅水平低于0.48 μmol/L时,仍可对婴儿神经行为发育产生不良影响.