Charge Distribution Reconstruction in a Bubbling Fluidized Bed Using a Wire-Mesh Electrostatic Sensor

The presence of electrostatic charge in a bubbling fluidized bed influences the operation of the bed. In order to maintain an effective operation, the electrostatic charges in different positions of the bed should be monitored. In this paper a wire-mesh electrostatic sensor is introduced to reconstruct the charge distribution in a bubbling fluidized bed. The wire-mesh sensor is fabricated by two mutually perpendicular strands of insulated wires. A Finite Element Model is built to analyze the sensing characteristics of the sensor. The sensitivity distributions of each wire electrode and the whole sensor are obtained from the model, which proves that wire-mesh electrostatic sensor has a higher and more uniform sensitivity distribution than single wire sensors. Experiments were conducted in a gravity drop test rig to validate the reconstruction method. Experimental results show that the charge distribution can be reconstructed when sand particles pass through the cross section of the sensor

Feasibility and safety of expandable mediastinoscopic and laparoscopic radical esophagectomy

BackgroundAt present, minimally invasive radical esophagectomy is the main surgical method for esophageal cancer treatment, but it has inherent limitations. We have developed a novel method of radical esophagectomy without thoracotomy to improve this situation, namely, by using EMLE. We evaluated the feasibility and safety of expandable mediastinoscopic and laparoscopic radical esophagectomy (EMLE) through a retrospective analysis.MethodsFrom January 2019 to June 2022, we successfully performed 106 cases of radical resection of esophageal cancer with this new surgical technique, gradually improved the surgical path, and recorded the perioperative data and postoperative complications of all patients.ResultsThe operation was successfully performed in all patients except for two patients who required a switch to open surgery. The mean operation time was 171.11 ± 33.29 min and the mean intraoperative blood loss was 93.53 ± 56.32 ml. The mean number of removed lymph nodes was 23.59 ± 5.42. The postoperative complications included pneumonia (3.77%), recurrent laryngeal nerve palsy (1.89%), anastomotic leak (14.15%), pleural effusion (5.66%), chylothorax (2.83%), and reoperation (4.72%). All complications were graded I–III per the Clavien–Dindo classification. No perioperative death was recorded.ConclusionExpandable mediastinoscopic and laparoscopic radical esophagectomy is feasible for radical resection of esophageal cancer, with good therapeutic effect and safety. Because of its minimal impact on patients and convenient operation, it is a novel surgical option for patients with esophageal cancer and is expected to become a standard surgical method for radical esophagectomy in the future

Surface Adjustment Strategy for a Large Radio Telescope with Adjustable Dual Reflectors

With the development of large-aperture and high-frequency radio telescopes, a surface adjustment procedure for the compensation of surface deformations has become of great importance. In this study, an innovative surface adjustment strategy is proposed to achieve an automated adjustment for the large radio telescope with adjustable dual reflectors. In the proposed strategy, a high-precision and long-distance measurement instrument is adopted and installed on the back of the sub-reflector to measure the distances and elevation angles of the target points on the main reflector. Here, two surface adjustment purposes are discussed. The first purpose is to ensure that the main reflector and sub-reflector are always positioned at their ideal locations during operation. The second purpose is to adjust the main reflector to the location of the best fitting reflector, and the sub-reflector to the focus of the best fitting reflector. Next, the calculation procedures for the adjustments of the main reflector and the sub-reflector are discussed in detail, and corresponding simulations are carried out to verify the proposed method. The results show that the proposed strategy is effective. This study can provide helpful guidance for the design of automated surface adjustments for large telescopes

Epileptiform response of CA1 neurones to convulsant stimulation by cyclothiazide, kainic acid and pentylenetetrazol in anaesthetized rats

AbstractWe have previously reported that cyclothiazide (CTZ) evokes epileptiform activities in hippocampal neurons and induces seizure behavior. Here we further studied in vivo the sensitivity of the hippocampal CA1 neurons in response to CTZ in epileptogenesis in comparison with two other classic convulsants of kainic acid (KA) and pentylenetetrazol (PTZ).CTZ administered intracerebral ventricle (i.c.v.) induced epileptiform activities from an initial of multiple evoked population spikes, progressed to spontaneous spikes and finally to highly synchronized burst activities in hippocampal CA1 neurons. PTZ, when given by subcutaneously, but not by intracerebral ventricle injection, evoked similar progressive epileptiform activities. In contrast, KA given by i.c.v. induced a quick development of epileptiform burst activities and then shortly switched to continuous high frequency firing as acute status epilepticus (ASE). Pharmacologically, alprazolam, a high-potency benzodiazepine ligand, inhibited CTZ and PTZ, but not KA, induced epileptiform burst activities while GYKI 53784, an AMPA receptor antagonist, suppressed CTZ and KA but not PTZ evoked epileptiform activities.In conclusion, CTZ and PTZ induced epileptiform activities are most likely to share a similar progressive pattern in hippocampus with GABAergic mechanism dominant in epileptogenesis, while CTZ model involves additional glutamate receptor activation. KA induced seizure in hippocampus is different to that of both CTA and PTZ. The results from this study indicate that hippocampal neurons respond to various convulsant stimulation differently which may reflect the complicated causes of the seizure in clinics

Panel Adjustment and Error Analysis for a Large Active Main Reflector Antenna by Using the Panel Adjustment Matrix

Active panels are generally applied in large aperture and high-frequency reflector antennas, and the precise calculation of the actuator adjustment value is of great importance. First, the approximation relationship between the adjustment value and panel elastic deformation is established. Subsequently, a panel adjustment matrix for the whole reflector is derived to calculate the reflector deformation caused by the actuator adjustment. Next, the root mean square (rms) error of the deformed reflector is expressed as a quadratic form in the matrix form, and the adjustment value can be derived easily and promptly from the corresponding extreme value. The solution is expected to be unique and optimal since the aforementioned quadratic form is a convex function. Finally, a 35 m reflector antenna is adopted to perform the panel adjustments, and the effect of the adjustment errors is discussed. The results show that compared with the traditional model, where the panel elastic deformation is not considered, the proposed method exhibits a higher accuracy and is more suitable for use in large reflectors with a high operation frequency. The adjustment errors in different rings exert different influences on the gain and sidelobe level, which can help determine the actuator distribution with different precisions

Reference-free THz-TDS conductivity analysis of thin conducting films

We present a reference-free method to determine electrical parameters of thin conducting films by steady state transmission-mode terahertz time-domain spectroscopy (THz-TDS). We demonstrate that the frequency-dependent AC conductivity of graphene can be acquired by comparing the directly transmitted THz pulse with a transient internal reflection within the substrate which avoids the need for a standard reference scan. The DC sheet conductivity, scattering time, carrier density, mobility, and Fermi velocity of graphene are retrieved subsequently by fitting the AC conductivity with the Drude model. This reference-free method was investigated with two complementary THz setups: one commercial fibre-coupled THz spectrometer with fast scanning rate (0.2-1.5 THz) and one air-plasma based ultra-broadband THz spectrometer for greatly extended frequency range (2-10 THz). Certain propagation correction terms for more accurate retrieval of electrical parameters are discussed. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreemen