Traction power substation balance and losses estimation in AC railways using a power transfer device through Monte Carlo analysis

The high dynamic power requirements present in modern railway transportation systems raise research challenges for an optimal operation of railway electrification. This paper presents a Monte Carlo analysis on the application of a power transfer device installed in the neutral zone and exchanging active power between two sections. The main analyzed parameters are the active power balance in the two neighbor traction power substations and the system power losses. A simulation framework is presented to comprise the desired analysis and a universe of randomly distributed scenarios are tested to evaluate the effectiveness of the power transfer device system. The results show that the density of trains and the relative branch length of a traction power substation should be considered in the evaluation phase of the best place to install a power transfer device, towards the reduction of the operational power losses, while maintaining the two substations balanced in terms of active power.

Methods for Increasing the Efficiency of Cleaning the Transfer Device

The article improves the quality of raw cotton by creating a new transfer device structure for the transportation of cotton in long-distance riots, located in the main building of the ginnery. Both foreign and domestic separator cleaners have been studied. Experiments were carried out on prototype transfer device and the results were obtained. The cleaning efficiency was determined by sampling the cotton entering the separator in the moving device and exiting after the inclined vibrating mesh surface installed after the separator.

ZnO Films on Transferable and Low Thermal Resistance Graphite Substrate Grown by Ultrasonic Spray Pyrolysis

ZnO thin films were deposited on graphite substrates by ultrasonic spray pyrolysis method with Zn（CH3COO）2·2H2O aqueous solution as precursor. The crystalline structure, morphology, and optical properties of the as-grown ZnO films were investigated systematically as a function of deposition temperature and growth time. Near-band edge ultraviolet （UV） emission was observed in room temperature photoluminescence spectra for the optimized samples, yet the usually observed defect related deep level emissions were nearly undetectable, indicating that high optical quality ZnO thin films could be achieved via this ultrasonic spray pyrolysis method. Considering the features of transferable and low thermal resistance of the graphite substrates, the achievement will be of special interest for the development of high-power semiconductor devices with sufficient vower durability.

High performance oscillator with 2-mW output power at 300 GHz

Material structures and device structures of a 100-GHz InP based transferred-electron device are designed in this paper. In order to successfully fabricate the Gunn devices operating at 100 GHz, the InP substrate was entirely removed by mechanical thinning and wet etching. The Gunn device was connected to a tripler link and a high RF （radio frequency） output with power of 2 mW working at 300 GHz was obtained, which is high enough for applications in current military electronic systems.

Application of Well-Known Antiviral Drugs in the Field Formed by the Unexplained Properties of Low-Level Laser Radiation in Therapy of Covid-19 and Chronic Viral Hepatitis

Low-level laser therapy (LLLT) or cold laser has been used in medicine for several decades. However, the method utilizes a direct contact of the light beam with a patient. Further research resulted in development of another method that enables remote transmission of the pharmacological properties of a medicament into a human body with the application of low-level laser radiation as the light source. 18 patients with different viral diseases were treated with the antiviral drugs placed into the field formed by the unexplained properties of low-level laser radiation of the “device for transfer of the pharmacological properties of a drug into the patient’s body”. This resulted in improvement of the patient’s condition, the absence of side effects and adverse reactions when using drugs in the proposed device and shortened therapy period for patients with chronic hepatitis C infection and Covid-19 patients. The long-term follow-up of the patients with chronic hepatitis B infection showed that hepatitis B virus remained at low replication levels under the influence of the therapy, which made it possible to avoid such formidable complications of the disease as cirrhosis of the liver and liver cancer.

GaN based transfer electron and avalanche transit time devices

A new model is developed to study the microwave/mm wave characteristics of two-terminal GaNbased transfer electron devices（TEDs）,namely a Gunn diode and an impact avalanche transit time（IMPATT） device.Microwave characteristics such as device efficiency and the microwave power generated are computed and compared at D-band（140 GHz center frequency） to see the potentiality of each device under the same operating conditions.It is seen that GaN-based IMPATT devices surpass the Gunn diode in the said frequency region.

Optimization of ohmic contact for InP-based transferred electronic devices

The effect of the annealing time and annealing temperature on Ni/Ge/Au electrode contacts deposited on the n-type InP contact layer has been studied using a circular transmission line model. The minimum specific contact resistance of 3.210 7 cm2was achieved on the low-doped n-type InP contact layer with a 40 s anneal at 425 ℃. In order to improve the ohmic contact and reduce the difficulty in the fabrication of the high doped InP epi-layer, the doping concentration in the InP contact layer was chosen to be 51018cm 3in the fabrication of transferred electronic devices. Excellent differential negative resistance properties were obtained by an electron beam evaporating the Ni/Ge/Au/Ge/Ni/Au composite electrode on an InP epi-layer with a 60 s anneal at 380 ℃.

2D hetero-structures based on transition metal dichalcogenides:fabrication,properties and applications

Recently,two dimensional transition metal dichalcogenides MX_2(M = Mo,W,etc; X = S,Se,Te) have ignited immense interests because of their unique structural and physical properties for the potential applications in the nano-optoelectronics,valley-spintronics etc. In terms of the structural compatibility and van der Waals interaction,two dimensional(2D) MX_2 layers can be fabricated into various lateral and vertical hetero-structures. The atomically-thin hetero-structures comprising different layered MX_2 provide a new platform for exploring fundamental physics and device technologies with unprecedented phenomenon and extraordinary functionalities. In this review,we report the recent progress about the fabrication,properties and applications of 2D hetero-structures based on transition metal dichalcogenides.

Design,fabrication and characterization of dual-channel real space transfer transistor

In this paper,using aδ-doping dual-channel structure and GaAs substrate,a real space transfer transistor(RSTT)is designed and fabricated successfully.It has the standardΛ-shaped negative resistance I-V characteristics as well as a level and smooth valley region that the conventional RSTT has.The negative resistance parameters can be varied by changing gate voltage(VGS).For example,the PVCR varies from 2.1 to 10.6 while VGS changes from 0.6 V to 1.0 V.The transconductance for IP(ΔIP=ΔVGS)is 0.3 mS.The parameters of VP,VV and threshold gate voltage(VT)for negative resistance characteristics arising are all smaller than the value reported in the literature.Therefore,this device is suitable for low dissipation power application.