An indoor air purification technology using a non-thermal plasma reactor with multiple-wire-to-wire type electrodes and a fiber air filter

For indoor air purification, long-term operation of the air purifier induces the growth of germs and the proliferation of molds, and results in the performance degradation of the air filter. Non-thermal plasma technology could be an effective countermeasure against these problems. Ozone generated by the electric discharge has significant germicidal power and does not produce secondary residual contaminants. Electrostatic force can enable the air filter to function as an electric precipitator. In this study, a non-thermal plasma reactor with wire-wire type electrodes and an air filter is investigated experimentally to improve the performance of the used air filter.     

Plasmonic Fraunhofer-wavelength narrow-band filter based on calcium film

We theoretically investigate plasmonic properties of a calcium film in a Kretschmann excitation scheme. Based on surface plasmon polaritons, the absorbance of the calcium film can be as high as 100% for the p-polarization, much higher than the absorbance for the s-polarization at the wavelength of 422.7 nm, correspondingly to the g Fraunhofer line. The 45 nm thick film of calcium has a high reflectance of about 76% at 422.7 nm for s-polarization. But for p-polarization, there is a minimum in the reflectivity curves at the angle of 19°. The narrow-band filter based on calcium film is particularly suited for working with conventional calcium atomic filter and on-chip integration due to its solid-state bulky feature. Furthermore, the plasmonic filter based on the calcium film is described that may offers new applications in angle- and polarization-sensitive sensor and the detection of weak laser light.     

Coupling of two-dimensional atomistic and continuum models for dynamic crack

A concurrent multiscale method of coupling atomistic and continuum models is presented in the two-dimensional system. The atomistic region is governed by molecular dynamics while the continuum region is represented by construct- ing the mass and stiffness matrix dependent on the coarsening of the grids, which ensures that they merge seamlessly. The low-pass phonon filter embedded in the handshaking region is utilized to effectively eliminate the spurious reflection of high-frequency phonons, while keeping the low-frequency phonons transparent. These schemes are demonstrated by numerically calculating the reflection and transmission coefficient, and by the further application of dynamic crack propa- gation subjected to mode-I tensile loading.     

Screening and identification of multiple constituents and their metabolites of Zhi‐zi‐chi decoction in rat urine and bile by ultra‐high‐performance liquid chromatography quadrupole time‐of‐flight mass spectrometry

Zhi‐zi‐chi decoction (ZZCD) is a classical formula widely used in Chinese clinical application. In the present study, a novel and efficient strategy has been developed for screening and identification of multiple constituents and their metabolites of ZZCD using ultra‐high‐performance liquid chromatography combined with triple time‐of‐flight mass spectrometry. The novel approach of an online data acquisition method dependent on multiple mass defect filter and dynamic background subtraction is combined with multiple data processing techniques. First, a total of 109 potential bioactive compounds were detected in ZZCD. Based on the same instrumental conditions, 100 compounds were found in rat biofluids after oral administration of ZZCD, including 61 original compounds of ZZCD as well as 39 metabolites. Conjugations with sulfate, glucuronate and amino acids were found as the predominant metabolic reaction of ZZCD. As more xenobiotics were detected in urine than those in bile were, it demonstrated that multiple components of ZZCD have undergone comprehensive renal excretion. This study reported the urinary and biliary excretion in rats after oral administration of ZZCD for the first time. The present study expands our knowledge about the constituents and metabolism of ZZCD, which could be very useful for further pharmacological and clinical studies of ZZCD.     

Passive Q-switch and mode-locking modulators for Nd:hosted lasers

Four kinds of currently available Nd:hosted laser passive Q-switch and mode-locking modulators: plastic dye sheet, LiF:F₂⁻ color center crystal, Cr⁺⁴ :YAG crystal and RG1000 colored glass filter were investigated in detail and summarized for comparison for the first time. The LiF:F₂⁻ crystal with outstanding annealability, long lifetime, low cost and operability at high repetition rates is highly recommended.     

Parallel implementation of data assimilation

Kalman filter is a sequential estimation scheme that combines predicted and observed data to reduce the uncertainty of the next prediction. Because of its sequential nature, the algorithm cannot be efficiently implemented on modern parallel compute hardware nor can it be practically implemented on large‐scale dynamical systems because of memory issues. In this paper, we attempt to address pitfalls of the earlier low‐memory approach described in and extend it for parallel implementation. First, we describe a low‐memory method that enables one to pack covariance matrix data employed by the Kalman filter into a low‐memory form by means of certain quasi‐Newton approximation. Second, we derive parallel formulation of the filtering task, which allows to compute several filter iterations independently. Furthermore, this leads to an improvement of estimation quality as the method takes into account the cross‐correlations between consequent system states. We experimentally demonstrate this improvement by comparing the suggested algorithm with the other data assimilation methods that can benefit from parallel implementation. Copyright © 2016 John Wiley & Sons, Ltd.     

Numerical analysis of charged particle collection in wire-plate ESP

In this paper, the structure of single wire-plate unit in electrostatic precipitator (ESP) was optimized and dust removal process in an entire ESP was investigated using computational fluid dynamics (CFD). Collection efficiency is higher in the center of the ESP, but becomes lower near the edges. High applied voltage, low inlet velocity and large particle diameter are beneficial for dust collecting. As particle concentration increases, collection efficiency increases at the beginning, then decreases. When particle diameter is smaller, inlet velocity and particle concentration is higher, particle trajectories become less stable as turbulence is more severe.     

Modeling the electrostatic effect on the hydrodynamic behavior in FCC risers: From understanding to application

A CFD simulation was proposed to investigate the electrostatic effect on the hydrodynamic behavior of turbulent gas–solid flow in FCC risers. The simulation was first verified using the open experimental data with expected electrostatic effects observed in FCC risers. The influences of several operating parameters on the degree of electrification in FCC risers were analyzed, such as surface charge densities, pressure, gas velocity. It was noted that the gas velocity played a highly significant role compared with solid flux, while the effect of pressure was relatively weak. Further analysis showed that a much stronger electrostatic effect was found in small-scale FCC risers than their large-scale counterparts, and in addition, the major regions affected by the electrostatic charge depend on the scale of the riser. Finally, an external electric field was applied to optimize the flow field distribution in the FCC riser. The results of the electrostatic effects on the hydrodynamic behaviors in FCC risers are of great use in providing a reference for the optimization of FCC risers and their scaling.