Event-triggered sliding mode control for switched genetic regulatory networks with persistent dwell time

This paper focus on the event-triggered sliding mode controller design for discrete-time switched genetic regulatory networks (GRNs) with persistent dwell time (PDT) switching. Firstly, the observation error dynamics of switched GRNs with PDT is constructed in the light of event-triggered sliding mode control (SMC) scheme. Next, sufficient conditions are derived to ensure the exponential stability of the augmented plant. Moreover, an event-triggered SMC law is synthesized to impel the system trajectories onto the sliding surface in a finite time. Finally, a verification example is provided to illustrate the effectiveness and potential of the proposed method.     

Surface plasmon resonance and electrochemistry for detection of small molecules using catalyzed deposition of metal ions on gold substrate

Small molecules are difficult to detect by conventional surface plasmon resonance (SPR) spectroscopy due to the fact that the changes in the refractive index resulted from the binding process of small biomolecules are quite small. Here, we report a simple and effective method to detect small biomolecule using SPR spectroscopy and electrochemistry by catalyzed deposition of metal ions on SPR gold film. As an example, the ascorbic acid-mediated deposition of Ag on gold film was monitored by in situ SPR spectrum. The deposition of Ag atom on gold film resulted in an obvious decrease of depth in SPR angular scan curves of reflectance intensity and minimum reflectivity angle. The depth change of the SPR reflectance intensity and minimum reflectivity angle curves mainly relied on the amount of Ag atom deposited on gold film that can be controlled by the concentration of ascorbic acid. By monitoring the deposition of Ag atom on gold film, ascorbic acid was detected in the concentration range of 2 × 10⁻⁵ M to 1 ×  10⁻³ M. After each of detections, the SPR sensor surface was completely regenerated by a potential step that stripped off the Ag atom. Furthermore, the regeneration process of the sensor surface provides the feasibility for detecting the concentration of ascorbic acid by electrochemical method.     

Fluoro-substituted DPP-bisthiophene conjugated polymer with azides in the side chains as ambipolar semiconductor and photoresist

Photoresists are essential for the fabrication of flexible electronics through all-photolithographic processes. Single component semiconducting photoresist exhibits both semiconducting and photo-patterning properties, and as a result, the device fabrication process can be simplified. However, the design of semiconducting polymeric photoresist with ambipolar semiconducting property remains challenging. In this paper, we report a single component semiconducting photoresist (PFDPPF4T-N₃) by incorporating azide groups and noncovalent conformation locks into the side alkyl chains and conjugated backbones of a diketopyrrolopyrrole-based conjugated polymer, respectively. The results reveal that PFDPP4FT-N₃ exhibits ambipolar semiconducting property with hole and electron mobilities up to 1.12 and 1.17 cm² V^?1 s^?1, respectively. Moreover, field effect transistors with the individual photo-patterned thin films of PFDPPF4T-N₃ also show ambipolar semiconducting behavior with hole and electron mobilities up to 0.66 and 0.80 cm² V^?1 s^?1, respectively. These results offer a simple yet effective design strategy for high-performance single component semiconducting photoresists, which hold great potential for flexible electronics processed by all photolithography.

     

Diastereoselective rhodium-catalyzed nitrene transfer starting from chiral sulfonimidamide-derived iminoiodanes

The dirhodium-catalyzed aziridination of olefins with chiral sulfonimidamides as iminoiodane precursors has been investigated under stoichiometric conditions. Diastereoisomeric excesses of up to 82% have been achieved using [Rh₂{(S)-nttl}₄] as catalyst. Matching and mismatching effects were observed upon use of chiral rhodium(II) carboxylate catalysts.     

碳酸二甲酯法合成1，5-二氨基甲酸甲酯的反应机理

应用红外光谱技术研究了在乙酸锌催化作用下1，5-萘二胺与碳酸二甲酯甲氧基羰基化反应机理．结果表明，二水合乙酸锌只有失去两个结晶水变成无水乙酸锌后才能产生催化活性．无水乙酸锌与1，5-萘二胺形成一个新的配位络合物，该配位络合物是一个适宜的亲核试剂，能与碳酸二甲酯进行亲核反应，生成1，5-萘二胺的甲氧基羰基化产物．在无水乙酸锌与1，5-萘二胺形成配位络合物的过程中，无水乙酸锌的结构从双齿型转变成单齿型．     

Fused multifunctionalized bridge aromatic hydrocarbons from in situ-generated arynes and anthracene derivatives

This study presents a facile strategy for the formation of highly substituted butterfly 1,4-adducts/9,10-adducts via the Diels–Alder reaction of benzyne intermediates. The method achieves very good to excellent yields of the respective anthracene derivatives under mild conditions. This practical protocol is compatible with a variety of sensitive functional groups and provides access to difunctionalized bridge 1,4-adducts/9,10-adducts.     

某些酚类的高温液相色谱行为

建立了高温液相色谱系统,在高温条件下,采用甲醇-水作为流动相,在Polymerx RP-1聚合物(PSDVB)色谱柱上考察了6种酚类样品的色谱行为.实验条件:温度40～160 ℃,流速0.2～5.5 mL/min,流动相中甲醇浓度范围40%～80%.考察了温度、流速和流动相组成对酚类样品的保留、分辨、柱效和系统压力的影响,探讨了酚类样品在聚合物柱上的热力学行为.温度升高2.35℃大约相当于流动相中甲醇浓度增加1%,可以通过改变色谱柱温度调节样品保留和改变选择性.柱温升高,降低了流动相的粘度,允许在高温条件下使用较高的流速实现快速分离.在160℃、V(甲醇):V(水)=40:60,为流动相和3 mL/min流速条件下,可于2.5 min内实现6种酚类的完全分离.     

核磁方法研究离子液体与丙酮的相互作用

运用核磁共振手段, 研究了室温离子液体1-辛基-3-甲基咪唑四氟硼酸盐([C8mim][BF4])在不同比例的离子液体／丙酮混合体系中1H和13C的化学位移及13C的自旋-晶格弛豫时间(T1). 结果表明, 离子液体[C8mim][BF4]的阳离子芳环上的氢原子, 以及与氮原子直接相连的甲基和亚甲基上的氢原子都与丙酮羰基上的氧原子有相互作用, 从而减弱了离子液体阴阳离子间的强相互作用, 使离子液体的运动加快, 黏度降低.     

纳米Ce1-xCoxO2-δ固溶体的水热合成及表征

采用水热方法, 在络合剂及氧化剂的辅助下合成出传统方法难以合成的Ce1-xCoxO2-δ固溶体. XRD结果表明, Ce1-xCoxO2-δ固溶体具有立方萤石结构; 产物的平均粒度约为4 nm. 小半径、低价态Co离子的掺杂导致晶格收缩. 结合XRD和Raman表征结果确定固溶体的固溶限约为x=0.06. 紫外光谱分析结果表明, Co离子以混合价态(+2, +3)存在于CeO2晶格中, 随着钴掺杂量的增大, 带隙逐渐蓝移. 低于固溶限样品的室温体相电导率随着钴含量增大而提高.     

Preparation and characterization of poly(propylene carbonate)/montmorillonite nanocomposites by solution intercalation

Poly(propylene carbonate) (PPC) is a new biodegradable aliphatic polycarbonate. However, the poor thermal stability and low glass transition temperatures (T_g) have limited its applications. To improve the thermal properties of PPC, organophilic montmorillonite (OMMT) was mixed with PPC by a solution intercalation method to produce nanocomposites. An intercalated-and-flocculated structure of PPC/OMMT nanocomposites was confirmed by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The thermal and mechanical properties of PPC/OMMT nanocomposites were investigated by thermal gravimetric analysis (TGA), differential scanning calorimetric (DSC), and electronic tensile tester. Due to the nanometer-sized dispersion of layered silicate in polymer matrix, PPC/OMMT nanocomposites exhibit improved thermal and mechanical properties than pure PPC. When the OMMT content is 4 wt%, the PPC/OMMT nanocomposite shows the best thermal and mechanical properties. These results indicate that nanocomposition is an efficient and convenient method to improve the properties of PPC.