The coil-to-globule transition of thermally sensitive linear poly（N-isopropylacrylamide） （PNIPAM） labeled with dansyl group is induced by 1.54 μm laser pulses （widths10 ns）. The dansyl group is used to follow t...The coil-to-globule transition of thermally sensitive linear poly（N-isopropylacrylamide） （PNIPAM） labeled with dansyl group is induced by 1.54 μm laser pulses （widths10 ns）. The dansyl group is used to follow the transition kinetics because its fluorescence intensity is very sensitive to its micro-environment. As the molar ratio of NIPAM monomer to dansyl group increases from 110 to 300, the effect of covalently attached dansyl fluorophores on the transition decreases. In agreement with our previous study in which we used 8-anilino- l-naphthalensulfonic acid ammonium salt free in water as a fluorescent probe, the current study reveals that the transition has two distinct stages with two characteristic times, namely, Tfast≈0.1 ms, which can be attributed to the nucleation and formation of some ＂pearls＂ （locally contracting segments） on the chain, and tslow≈0.5 ms, which is related to the merging and coarsening of the ＂pearls＂.Tfast is independent of the PNIPAM chain length over a wide range （Mw=2.8× 10^6-4.2 × 10^7 g/mol）. On the other hand, Tslow only slightly increases with the chain length.展开更多
Labelled transition systems(LTSs) are widely used to formally describe system behaviour.The labels of LTS are extended to offer a more satisfactory description of behaviour by refining the abstract labels into multiva...Labelled transition systems(LTSs) are widely used to formally describe system behaviour.The labels of LTS are extended to offer a more satisfactory description of behaviour by refining the abstract labels into multivariate polynomials.These labels can be simplified by numerous numerical approximation methods.Those LTSs that can not apply failures semantics equivalence in description and verification may have a chance after using approximation on labels.The technique that combines approximation and failures semantics equivalence effectively alleviates the computational complexity and minimizes LTS.展开更多
A p-type transition metal dichalcogenide(WS2)was synthesized and hybridized with graphene oxide via a simple hydrothermal method.The as-prepared material was used to modify a glassy carbon electrode for the fabricatio...A p-type transition metal dichalcogenide(WS2)was synthesized and hybridized with graphene oxide via a simple hydrothermal method.The as-prepared material was used to modify a glassy carbon electrode for the fabrication of a simple,stable,and repeatable methylene blue-labeled“signal-off”aptasensor used for the sensitive determination of very low amounts of sodium diclofenac(DCF).The synthetic material,modification process,and role of WS2 in the current response enhancement were studied by X-ray diffraction,energy-dispersive X-ray spectroscopy,field emission scanning electron microscopy,high resolution transmission electron microscopy,Hall effect,cyclic voltammetry,differential pulse voltammetry,and electrochemical impedance spectroscopy.Subsequently,a wide linear range of DCF concentration(0.5-300 nmol/L),very low limit of detection(0.23 nmol/L),and good selectivity were obtained using the differential pulse voltammetry method with the assembled aptasensor.Finally,the fabricated aptasensor was successfully developed for physiological real samples with significant recoveries.展开更多
越来越多的系统采用UML(unified model language,统一建模语言)作为建模语言来进行系统分析和设计.UML活动图是UML语言中描述系统动态行为的一种方法,它广泛地运用于业务建模.由于UML活动图缺乏精确的动态语义,所以不利于对其所描述的...越来越多的系统采用UML(unified model language,统一建模语言)作为建模语言来进行系统分析和设计.UML活动图是UML语言中描述系统动态行为的一种方法,它广泛地运用于业务建模.由于UML活动图缺乏精确的动态语义,所以不利于对其所描述的系统进行形式化的分析、验证和确认.为解决这一问题,根据UML1.5语义文档,给出UML活动图的形式化操作语义.首先给出UML活动图的形式化的语法,然后详细地定义了活动图的格局和变迁,最后基于LTS给出了活动图的演绎规则.主要工作是:引入状态包的概念,使得描述更加清楚、完善;通过LTS定义活动图的操作语义,并详细阐述演绎规则,从而获得活动图的全局状态转移图,使定义的操作语义很容易地应用到形式化验证中.该语义覆盖了UML活动图的绝大部分特征,为对UML活动图进行模型检验奠定了基础.展开更多
随着嵌入式计算机系统应用的不断扩展,嵌入式系统的可靠性引起了学术界和工业界的广泛关注,也提出了很多增进可靠性的方法和技术.然而,现有的方法和技术在测试套生成方面论述不多,所以在处理大批量嵌入式系统测试工作中遇到了挑战.讨论...随着嵌入式计算机系统应用的不断扩展,嵌入式系统的可靠性引起了学术界和工业界的广泛关注,也提出了很多增进可靠性的方法和技术.然而,现有的方法和技术在测试套生成方面论述不多,所以在处理大批量嵌入式系统测试工作中遇到了挑战.讨论抽象测试套生成方法和适配技术,提出了LTS(labeled transition system)到BT(behavior tree)的转换算法,从而使TTCN(test and testing control notation)测试套可以通过转换嵌入式软件的LTS描述产生.还介绍了基于上述转换算法的嵌入式软件测试工具包,以及一个嵌入式物联网识读器测试案例研究.展开更多
文摘The coil-to-globule transition of thermally sensitive linear poly（N-isopropylacrylamide） （PNIPAM） labeled with dansyl group is induced by 1.54 μm laser pulses （widths10 ns）. The dansyl group is used to follow the transition kinetics because its fluorescence intensity is very sensitive to its micro-environment. As the molar ratio of NIPAM monomer to dansyl group increases from 110 to 300, the effect of covalently attached dansyl fluorophores on the transition decreases. In agreement with our previous study in which we used 8-anilino- l-naphthalensulfonic acid ammonium salt free in water as a fluorescent probe, the current study reveals that the transition has two distinct stages with two characteristic times, namely, Tfast≈0.1 ms, which can be attributed to the nucleation and formation of some ＂pearls＂ （locally contracting segments） on the chain, and tslow≈0.5 ms, which is related to the merging and coarsening of the ＂pearls＂.Tfast is independent of the PNIPAM chain length over a wide range （Mw=2.8× 10^6-4.2 × 10^7 g/mol）. On the other hand, Tslow only slightly increases with the chain length.
基金National Natural Science Foundation of China(No.11371003)Natural Science Foundations of Guangxi,China(No.2011GXNSFA018154,No.2012GXNSFGA060003)+2 种基金Science and Technology Foundation of Guangxi,China(No.10169-1)Scientific Research Project from Guangxi Education Department,China(No.201012MS274)Open Research Fund Program of Guangxi Key Laboratory of Hybrid Computation and IC Design Analysis,China(No.HCIC201301)
文摘Labelled transition systems(LTSs) are widely used to formally describe system behaviour.The labels of LTS are extended to offer a more satisfactory description of behaviour by refining the abstract labels into multivariate polynomials.These labels can be simplified by numerous numerical approximation methods.Those LTSs that can not apply failures semantics equivalence in description and verification may have a chance after using approximation on labels.The technique that combines approximation and failures semantics equivalence effectively alleviates the computational complexity and minimizes LTS.
文摘A p-type transition metal dichalcogenide(WS2)was synthesized and hybridized with graphene oxide via a simple hydrothermal method.The as-prepared material was used to modify a glassy carbon electrode for the fabrication of a simple,stable,and repeatable methylene blue-labeled“signal-off”aptasensor used for the sensitive determination of very low amounts of sodium diclofenac(DCF).The synthetic material,modification process,and role of WS2 in the current response enhancement were studied by X-ray diffraction,energy-dispersive X-ray spectroscopy,field emission scanning electron microscopy,high resolution transmission electron microscopy,Hall effect,cyclic voltammetry,differential pulse voltammetry,and electrochemical impedance spectroscopy.Subsequently,a wide linear range of DCF concentration(0.5-300 nmol/L),very low limit of detection(0.23 nmol/L),and good selectivity were obtained using the differential pulse voltammetry method with the assembled aptasensor.Finally,the fabricated aptasensor was successfully developed for physiological real samples with significant recoveries.
文摘越来越多的系统采用UML(unified model language,统一建模语言)作为建模语言来进行系统分析和设计.UML活动图是UML语言中描述系统动态行为的一种方法,它广泛地运用于业务建模.由于UML活动图缺乏精确的动态语义,所以不利于对其所描述的系统进行形式化的分析、验证和确认.为解决这一问题,根据UML1.5语义文档,给出UML活动图的形式化操作语义.首先给出UML活动图的形式化的语法,然后详细地定义了活动图的格局和变迁,最后基于LTS给出了活动图的演绎规则.主要工作是:引入状态包的概念,使得描述更加清楚、完善;通过LTS定义活动图的操作语义,并详细阐述演绎规则,从而获得活动图的全局状态转移图,使定义的操作语义很容易地应用到形式化验证中.该语义覆盖了UML活动图的绝大部分特征,为对UML活动图进行模型检验奠定了基础.
文摘随着嵌入式计算机系统应用的不断扩展,嵌入式系统的可靠性引起了学术界和工业界的广泛关注,也提出了很多增进可靠性的方法和技术.然而,现有的方法和技术在测试套生成方面论述不多,所以在处理大批量嵌入式系统测试工作中遇到了挑战.讨论抽象测试套生成方法和适配技术,提出了LTS(labeled transition system)到BT(behavior tree)的转换算法,从而使TTCN(test and testing control notation)测试套可以通过转换嵌入式软件的LTS描述产生.还介绍了基于上述转换算法的嵌入式软件测试工具包,以及一个嵌入式物联网识读器测试案例研究.
