Precise measurement and control of the pressure-driven flows for microfluidic systems

The pressure-driven device is designed and the flow rates of the microfluidic systems can be supplied by the pressure-driven flows, which can significantly reduce the flow-rate fluctuations coming from the pump source. For pressure-driven flows, the flow rates of the fluids can be predicted by measuring the pressure drop along a polytetrafluoroethylene (PTFE) tubing. Especially, by varying the geometrical parameters of the PTFE tubing, the predicted flow rates of the fluids are compared with the experimental measurements, and the testing precision of the pressure-driven flows can be obtained. Meanwhile, the dynamic characteristics of the open-loop and closed-loop control pressure-driven device are comparatively studied. Particularly, a proportional and integral (PI) controller is integrated with the closed-loop control pressure-driven device, and the effects of the parameters of the PI controller on the dynamic characteristics of the pressure-driven devices are mainly discussed. Most importantly, by improving the dynamic characteristics of the pressure-driven devices, precise measurement and control of the pressure-driven flows can be achieved for microfluidic systems.     

Chemical composition and anti-complement activity of Glechomae Herba collected in different months

Glechomae Herba (GH) is derived from the dried aerial part of Glechoma longituba (Nakai) Kupr., which is harvested from spring to autumn. It has the effects of clearing heat and detoxification. The aim of this paper was to study the chemical composition and the anti-complement activity of GH collected in different months. Ultra-high-performance liquid chromatography coupled to quadrupole time-of-flight tandem mass spectrometry based on predicted compounds screening and diagnostic ion filter strategy was developed for identifying the chemical composition of GH collected in different months. A total of 102 compounds—40 chlorogenic acids (CGAs), 32 phenolic acids, and 30 flavonoids—were reasonably identified in GH. Thirty-four CGAs were discovered in GH for the first time. The correlations between chemical compositions and anti-complement activities of GH collected in different months were analyzed. Phenolic acids and flavonoids were found to be negatively correlated with anti-complement activity, and CGAs were positively correlated with anti-complement activity. At the same time, six CGA standards had obvious anti-complement activity. It was demonstrated that different harvest months had a significant impact on the difference in chemical composition and anti-complement activity of GH. And CGAs might play an important role in the anti-complement activity of GH.     

Cobalt(II)-Catalyzed [4+2] Annulation of Picolinamides with Alkynes via C−H Bond Activation

A cobalt(II)-catalyzed [4+2] annulation of picolinamides with alkynes via C−H bond activation has been developed. The operationally simple annulation reaction allows for the synthesis of acyl-substituted 1H-benzoquinoline bearing multiple aromatic rings (up to 96 % yield) without co-oxidant or other oxidation factors under mild conditions. Several control experiments were carried out. This practical [4+2] annulation provides an efficient route to access highly functionalized compounds.     

Rational design of perfluorinated sulfonic acid ionic sieve modified separator for high-performance Li-S battery

Journal of Solid State Electrochemistry - Practical application of Li-S battery is limited by the fast capacity decay and low coulombic efficiency caused by the shuttling phenomenon. Modification...     

Preparing molecularly imprinted nanoparticles of saponins via cooperative imprinting strategy

Saponin is an important class of natural products with various pharmacological activities. The selective separation of saponins is an essential step before further analysis. Molecular imprinting has been an effective strategy for preparing antibody mimics. However, a facile and efficient imprinting strategy for saponins is still lacking owing to their amphiphilic nature. Herein, we have prepared the saponins imprinted nanoparticles via cooperative imprinting strategy. This new strategy relies on the combination of various non‐covalent interactions (hydrophobic and hydrogen bonding) and covalent boronate affinity interactions. The obtained imprinted nanoparticles could rebind specific saponins from complex matrices with good selectivity, superb tolerance to interference, and fast binding equilibrium. This method was verified to be versatile and facile. Thus, this strategy could greatly facilitate the preparation of imprinted nanoparticles for the specific recognition of saponins.     

One-step method for preparing the experimental pure state in nuclear magnetic resonance

Quantum computing is an emerging and promising research field in modern quantum physics and is committed to accelerating traditional calculation processes using the principle of quantum mechanics[1,2].Several computation models have been proposed,including the circuit model[3],topologic quantum computation[4],adiabatic quantum computing[5],and duality quantum computing[6-8].Universal quantum computation generally includes a system initialization,evolutionary control,and a final-state readout[9],where the preparation of the initial state is a key step in the entire process.     

N-substituted-3(10H)-acridones as visible-light photosensitizers for organic photoredox catalysis

N-Substituted-3(10H)-acridones have been established as visible-light organic photocatalyst. These photosensitizers are efficient for oxidative coupling reaction of N-aryl tetrahydroisoquinolines with various nucleophiles. Notably, N-methyl-3(10H)-acridone (Ia) is stable and can be effectively prepared. It is a water-soluble and atom-economic catalyst, and thus holds promise for green chemical applications. Mechanistic studies confirm a single electron transfer (SET)-induced radical process and a rate-limiting step. Analysis of the photocatalytic reactivity?structure relationship reveals that the acridones are robust and tunable photosensitizers for photoredox catalysis.     

Eigenspaces of symmetric graphs are not typically irreducible

We construct rich families of Schrödinger operators on symmetric graphs, both quantum and combinatorial, whose spectral degeneracies are persistently larger than the maximal dimension of an irreducible representation of the symmetry group.     

Long—Range Effects on the Pyroelectric Coefficient of Ferroelectric Superlattice

Long-range effects on the pyroelectric coefficient of a ferroelectric superlattice consisting of two different ferroelectric materials are investigated based on the transverse Ising model.The effects of the interfacial coupling and the thickness of one period on the pyroelectric coefficient of the ferroelectric superlattics are studied by taking into account the long-range interaction.It is found that with the increase of the strength of the long-range interaction,the pyroelectric coefficient decreases when the temperature is lower than the phase transition temperature;the mumber of the pyroelectric peaks decreases gradually and the phase transition temperature increases,It is also found that with the decrease of the interfacial coupling and the thickness of one period.the phase transition temperature and the number of the pyroelectric peaks decrease.