N-(2,3-Dimeth­oxy­benzyl­idene)naphthalen-1-amine

The title compound, C19H17NO2, represents a trans isomer with respect to the C=N bond. The dihedral angle between the planes of the naphthyl ring system and the benzene ring is 71.70 (3)°. In the crystal, weak C—H⋯O hydrogen bonding is present

Micro-Clearance Oil Film Temperature Field Characteristics of High Speed and Heavy Type Hydrostatic Thrust Bearing under Extreme Operating Conditions

To explore the micro-clearance oil film temperature field characteristics of hydrostatic thrust bearings under operating conditions of high speed and heavy load, a mathematical model of micro-clearance oil film is established. According to the principle of computational fluid dynamics, the relationship between load capacity and rotational speed is calculated, and the model is solved using the finite volume method. The micro-clearance oil film temperature field is also investigated and tested to verify the theoretical analysis. The results show that the rotational speed is coupled with the load-carrying capacity of hydrostatic thrust bearings. When the extreme operating conditions are between 0t-228.9r/min and 4t-214.9r/min, the oil film maximum temperature increases slowly with the load increase and rotational speed decrease, and the average temperature decreases slowly. On the other hand, when the extreme operating conditions are between 4t-214.9r/min and 32t-78.9r/min, the maximum temperature and the average temperature slowly decrease as the load increases and the rotational speed decreases; the influence of rotational speed is greater than that of load, and the temperature rise of the upstream side is sharper than that of the downstream side

Quality Mapping of Offset Lithographic Printed Antenna Substrates and Electrodes by Millimeter-Wave Imaging

Offset lithographic printed flexible antenna substrate boards and electrodes have attracted much attention recently due to the boost of flexible electronics. Unmanned quality inspection of these printed substrate boards and electrodes demands high-speed, large-scale and nondestructive methods, which is highly desired for manufacturing industries. The work here demonstrates two kinds of millimeter (mm)-wave imaging technologies for the quality (surface uniformity and functionality parameters) inspection of printed silver substrates and electrodes on paper and thin polyethylene film, respectively. One technology is a mm-wave line scanner system and the other is a terahertz-time domain spectroscopy-based charge-coupled device (CCD) imaging system. The former shows the ability of detecting transmitted mm-wave amplitude signals only; its detection is fast in a second time scale and the system shows great potential for the inspection of large-area printed surface uniformity. The latter technology achieves high spatial resolution images of up to hundreds of micrometers at the cost of increased inspection time, in a time scale of tens of seconds. With the exception of absorption rate information, the latter technology offers additional phase information, which can be used to work out 2D permittivity distribution. Moreover, its uniformity is vital for the antenna performance. Additionally, the results demonstrate that compression rolling treatment significantly improves the uniformity of printed silver surfaces and enhances the substrate’s permittivity values

Investigation of a GL-EMMS gradual drag model by comparative simulations of bubble columns

The mesoscale model for gas-liquid flow based on the energy minimization multi-scale method, which is denoted by the GL-EMMS model, demonstrates its capability of predicting the regime transition in bubble columns. Since the dominant mechanisms and stability conditions are important for this mesoscale model, it is desirable to reveal more details through the computational fluid dynamics (CFD) work. This work proposes a gradual drag correlation based on the GL-EMMS model, and then incorporates it into the Euler-Euler (E-E) and Euler-Lagrange (E-L) frameworks respectively. Cases with different gas distributors are simulated via the opensource platform of OpenFOAM. A simplified meshing treatment of the inlet boundary is adopted and has proven effective to reducing the computing load. The E-E simulation predicts the total gas holdup and the radial distribution of liquid velocity well, but obvious deviation is observed in the radial distribution of gas holdup, especially at lower superficial gas velocities for the single-orifice aeration. Nonetheless, this shortage can be overcome saliently by the E-L method. These verified simulations enable further possible iterative investigation between the GL-EMMS model and the CFD work, and also inspire some meaningful simulating strategy for bubble columns. (c) 2021 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved

Dual channel dual focus optical coherence tomography for imaging accommodation of the eye

A dual channel dual focus spectral-domain optical coherence tomography was developed for imaging the accommodation of the eye in real time. The system can provide simultaneous cross-sectional imaging of all the surfaces of the anterior segment of the eye including the cornea, anterior chamber, anterior and posterior surfaces of the crystalline lens. Thus, the modification of the curvatures of the anterior and posterior surfaces of the crystalline lens and the dimensions of the anterior segment of the eye with accommodation can be calculated. The system was successfully tested in imaging accommodation. The preliminary results demonstrated the feasibility of this novel approach

Direct visualization of tear film on soft contact lens using ultra-high resolution spectral domain optical coherence tomography

The integrity of the tear film on the surface of contact lenses is essential to maintaining visual clarity and the overall health of the superficial structures of the eye (cornea and conjunctiva) for contact lens wearers. It is very critical to evaluate pre- and post-lens tear films in contact lens practice to make sure the lens is properly fitted. Improper lens fitting may cause ocular discomfort, visual distortion and ocular infection. It is very often for soft contact lens wearers to experience dry eye, especially in the afternoon after wearing the lens for a period of time. Dry eye has been a common cause of contact lens drop-off. There is currently no method available to directly visualize the tears on and underneath the contact lens in situ on human eye, mainly due to the extremely difficulty in imaging the micrometer-thin tear layer. An ultra-high resolution spectral domain optical coherence tomography has been developed with a telecentric light delivery system mounted with a slit-lamp. The system has a 3 micrometer depth resolution with a scan width up to 15 mm. The system was used to image soft contact lenses on the human eye. For the first time to our knowledge, tear films on the center and edge of the soft contact lens were directly visualized in vivo