Double Drift Research Articles

Stereo Vision Based Localization of Handheld Controller in Virtual Reality for 3D Painting Using Inertial System

Google Tilt Brush is expensive for virtual drawing which needs further improvement on the functionalities of mechanisms rather than implementation expects addressed in this research. Several issues are addressed by this research in this context, i.e., noise removal from sensor data, double integration-based drift issues and cost. Recently, available smart phones do not have the ability to perform drawing within artificial settings handling cardboard and daydream of google without purchasing Oculus Rift and HTC Vive (Virtual Reality Headset) because of expensiveness for large number of users. In addition, various extrinsic hardwares, i.e., satellite localization hardware and ultrasonic localization applications are not used for drawing in virtual reality. Proposed methodology implemented extended Kalman filter and Butterworth filter to perform positioning using six degree of freedom using Microelectromechanical Applications (MEMS) software data. A stereo visual method using Simultaneous Localization and Mapping (SLAM) is used to estimate the measurement for positioning implicating mobile phone (i.e., android platform) for the hardware system to estimate drift. This research implemented Google Virtual Reality application settings Kit with Unity3D engine. Experimentation validation states that proposed method can perform painting using virtual reality hardware integrated with controller software implicating smartphone mobile without using extrinsic controller device, i.e., Oculus Rift and HTC Vive with satisfactory accuracy.

Prediction and Online Optimization of Strip Shape in Hot Strip Rolling Process Using Sparrow Search Algorithm‐Online Sequential‐Deep Multilayer Extreme Learning Machine Algorithm

In the hot strip process, the prediction of strip shape is a key factor to improve the quality of products. However, strip‐shape prediction models based on traditional machine learning algorithms with relatively simple network structures often rely on data preprocessing and feature selection. Herein, five strip‐shape prediction models are proposed by combining sparrow search algorithm (SSA), particle swarm optimization algorithm (PSO), extreme learning machine (ELM), and deep multilayer extreme learning machine (DELM). The prediction experiments show that the SSA‐DELM model has highest accuracy, and the determination coefficient (R2) of crown prediction and flatness prediction of SSA‐DELM model is 0.971 and 0.979. 100% of the samples have a prediction error of less than ±7 μm and ±7 IU. Furthermore, to solve the problem of concept drift affecting prediction accuracy in industrial processes, online optimization method is proposed. Especially, online sequential deep ELM model (OS‐DELM) optimized by SSA and guided by double window drift detection is proposed to fill the gap. Compared with other online optimization methods, the update time with this method can be reduced by up to 83.05% averagely, which is more suitable for online strip‐shape prediction in hot rolling process.

Bias Current Modulation of DC and RF Properties of AlmGa1‐m∼GaN Heterojunction IMPATT at Sub‐Millimeter Wave Frequency

AbstractLarge signal RF properties of double drift region (DDR) Impact Avalanche Transit Time (IMPATT) device based on AlmGa1‐m∼GaN heterojunction (HT) are investigated and their variation with bias currents has been presented here. These RF properties and their modulation will significantly validate the acceptability of the particular HT in the sub‐millimeter wave frequency domain. Avalanche noise plays the prime ground for making the IMPATT diode basically noisy and tunneling decays the performance of the device, as we move towards the higher frequency range like the sub‐millimeter frequency. These setbacks can be done with if the homojunction (HM) is replaced by heterojunction. This authenticates the choice of heterojunction over homojunction. Here, the author takes 500 GHz as the frequency of concern in the sub‐millimeter wave range. Here, two complementary heterojunctions of AlmGa1‐m∼GaN is taken with m = 0.4 or the mole fraction of Al in the alloy being 40% and their RF results are compared with two homojunctions of GaN and AlGaN for double drift region (DDR) IMPATT diode. Outcomes indicate that HT diodes surpass the high‐frequency performance of HM diodes if compared on the basis of dc to RF conversion efficiency and output power due to the influence of large amplitude ac signal. It is also observed that with increasing bias voltage dependent current, which is varied from 20 × 108to 40 × 108Am−2, the efficiency of conversion together with the power output increases. These results will be very important for further research in this domain.

Numerical Study of Rock Damage Mechanism Induced by Blasting Excavation Using Finite Discrete Element Method

In this paper, the mechanism of rock damage induced by blasting excavation is numerically studied by using an FDEM-based multiphysics fracture analysis software, MultiFracS. Based on the drainage channel project of Guanggu 1st Road to Gaoxin 4th Road, a numerical model considering the near-field fracture process is established to study the influence of a millisecond delay and construction technology on the blasting excavation. Firstly, the double side drift method model is established to analyze the influence of different millisecond delays on the peak blasting vibration velocity. Then, the rock fracture process of the surrounding rock around the blast holes under the blasting excavation construction technology of the double side drift method, the reserved core soil method, and the CRD method is studied, respectively. The numerical simulation results show that the mainshock phases of the blasting vibration velocity waveform generated by different bores overlap when the millisecond delay is small. With the increase in the millisecond delay, the mainshock phase is gradually separated, and the superposition effect of the blasting vibration is weakened. When the millisecond delay is greater than 40 ms, the peak blasting vibration velocity is not affected by the millisecond delay. In the three kinds of blasting excavation construction technologies, the double side drift method has a better effect on the deformation and the fracture control of the surrounding rock. The optimal millisecond delay and the rock fracture evolution process of the surrounding rock around blast holes with different blasting excavation construction technologies are obtained.

Study on Underground Excavation Construction Technology of TBM with Tunnel First Excavated and then Expanded into Platform Based on Double Side Drift Method

Study on Underground Excavation Construction Technology of TBM with Tunnel First Excavated and then Expanded into Platform Based on Double Side Drift Method

Ensuring the excavation workings stability when developing excavation sites of flat-lying coal seams by three workings

On the basis of analysis of mining plans and field studies at mines of JSC SUEK-Kuzbass, it is shown that in conditions of increasing the size of excavation columns during the development of flat-lying coal seams the stress-strain state of the rock mass along the workings length changes significantly. The necessity of predicting the stress-strain state at the design stage of the workings timbering standards, as well as subsequent monitoring of the workings roof state and its changes in the mining operations using video endoscopes, is noted. The results of numerical studies of the stress-strain state of the rock mass during the development of excavation sites by three workings for various combinations of width of the pillars between the workings for mining-geological and mining-technical conditions of the “Taldinskaya-Zapadnaya-2” mine are provided. The stresses in the vicinity of the three workings are compared with the values obtained during the development of the excavation sites by double drift. A set of recommendations on the choice of the location of the workings, the width of pillars, timbering standards that ensure the stable condition of the workings throughout the entire service life at the minimal losses of coal in the pillars is presented.

Space charge studies in graphene based avalanche transit time devices

Avalanche multiplication process in avalanche transit time devices results in large number of electrons-hole pairs (EHPs). Therefore, there is considerable temperature rise in the junction. This high temperature than normal operating one, leads to large space charge effects by creating extra space charges. As a result, practical efficiency of transit time devices is below 30%. It is quite important to understand the effects of space charges on device performances. The space charge effect is computationally studied and analysed here for the graphene material based double drift region (DDR) impact ionization and avalanche transit time (GIMPATT) diode. Also, the effect in GIMPATT is compared with IMPATT based on other material like Si, Ge, GaAs, WzGaN, InP, 4H–SiC. • There is considerable temperature rise in the junction of avalanche transit time devices. • This high temperature than normal operating one, leads to large space charge effects by creating extra space charges. • Practical efficiency of transit time devices is below 30%. It is important to understand the effects of space charges. • The space charge effect is computationally studied and analysed here for the GIMPATT diode . • The effect in GIMPATT is compared with IMPATT based on other material like Si, Ge, GaAs, WzGaN, InP, 4H–SiC.

Optimal Design of Large Signal and Noise Performance of GaN/SiC Hetero-Structural IMPATT Diodes Based on QCDD Model

Successes of GaN and SiC electronics in high frequency, large power realm indicate that, the GaN/SiC hetero-structures can be used to design the impact avalanche transit time (IMPATT) diodes operating at Terahertz range, of which holds advantages over homo-structural counterparts in lower noise and reduced tunnel current. Here, the (n)GaN/(p)SiC and (p)GaN/(n)SiC double drift region (DDR) IMPATT diodes operating at 0.85 THz are proposed based on the quantum corrected drift-diffusion (QCDD) model, the performance parameters of static state, large signal and noise properties of the studied devices such as peak electric field intensity, breakdown voltage, optimal negative conductance, output power, conversion efficiency, admittance-frequency relation, quality factor, noise electric field, mean-square noise voltage per band-width and noise measure were numerically calculated and analyzed, which can guide to optimize the GaN/SiC IMPATT diodes.

Reducing the specific on-resistance for a trench-gate-integrated SOI LDMOS by using the double silicon drift layers

Double silicon drift layers are used to reduce the specific on-resistance (Ron,sp) for a trench-gate-integrated lateral double-diffused MOSFET (DDL TG LDMOS) based on SOI technology in this paper. A trench-gate is incorporated into the oxide trench, a n-type drift layer with a high doping concentration is introduced on the topside of the original drift layer around the oxide trench, and a p-type pillar layer with a high doping concentration is inserted between the dual drift layers. First, the incorporated trench-gate constitutes dual current conduction channels, which decreases the Ron,sp. Second, the whole electric fields on the device surface and around the oxide trench are modulated on the basis of RESURF condition, leading to a higher breakdown voltage (BV) at off-state. Finally, the doping concentration of the drift layers is increased by an assistant depletion effect from the p-pillar, which not only improves the BV but also reduces the Ron,sp. Consequently, compared with those of the conventional trench SOI LDMOS on the same drift region of 18 μm and top silicon layer of 25 μm, a higher BV of 477 V and a lower Ron,sp of 32.1 mΩ∙cm2 are obtained for the DDL TG SOI LDMOS, while BV is improved by 33.5% and Ron,sp is reduced by 92.9%, respectively.

Stability Analysis of Neighborhood Tunnels with Large Section Constructed in Steeply Jointed Rock Mass

To investigate the instability of two neighborhood tunnels with large crossing section during the construction, the Tushan subway station was taken as study background, which was built in steeply jointed rock mass. Based on the excavation method called traditional double side drift, numerical simulations of four different face excavation sequences in the two neighborhood tunnels were conducted to optimize construction sequence to improve the stability during tunneling. The results show that first excavation of the right tunnel produced less deformation of the tunnels due to joints dip. The effects of rock mass discontinuities on the stability of the tunnels were studied through comparison between the real condition with joints and the assumed condition without joints. Furthermore, six initial supporting systems with different parameters were compared, and the field observations of deformations along tunnel profile show good agreement with the numerical results. Based on the numerical simulation, the length of rock anchors could be designed asymmetrically, which is more economical than the symmetrical design. The optimized thickness of shot concrete and spacing of steel sets was 35 cm and 60 cm, respectively.

Computation of quantum‐corrected noise in graphene‐SiC‐based impact avalanche transit time diode

AbstractHere, we have performed the noise analysis in graphene‐SiC‐based double drift region impact avalanche transit time diode (IMPATT). For computation, the noise model taken is based on drift diffusion with quantum corrections. Though noise computation in IMPATT with classical drift diffusion model are widely followed in earlier years, noise analysis through classical drift diffusion model is independent of confinement and tunneling due to quantum effects. Noise computed through quantum‐corrected noise model is more accurate to measured noise. Therefore, by considering quantum effects in addition to classical noise model, we have computed the noise in graphene‐SiC IMPATT. The noise performance of graphene‐SiC IMPATT is evaluated at Ka band which ranges from 26.5 to 40 GHz. The obtained noise from graphene‐SiC IMPATT is in good agreement with earlier reported noise behavior in IMPATT. We observed that the graphene‐SiC IMPATT is giving the better noise performance in terms of lower computed noise and noise spectral density as compared to other materials reported so far.

Comparative Analysis of Different Construction Methods for Mine Tunnels

The construction of mining tunnels in cities often has a great impact on the stratum and surrounding environment. Relying on a drainage tunnel project in Wuhan, Plaxis3D finite element analysis software is used to simulate tunnel excavation under four typical construction methods. The ground conditions, tunnel size, burial depth, support and construction scheme are all guaranteed to be the same. The characteristics and rules of ground settlement, crown settlement and horizontal convergence caused by construction are mainly analyzed. The following results are obtained: For the four construction methods, the rules of ground settlement, crown settlement and horizontal convergence by tunnel excavation are basically the same. Except for the arch bottom uplift, the calculation results of the tunnel constructed by the double side drift method are the smallest, and the calculation results of the tunnel constructed by the bench method are the largest. The tunnels excavated by the CRD method and the CD method have similar calculation results and have relatively little impact on the stratum. The research results can provide references for other related projects in Wuhan.

Experimental Study on Thermal Behaviour of Double Pipe Helical Flow Heat Exchanger

The warmth among the fluids is transferred by a tool named warmth exchanger. Now a days, various types of heat exchangers existed with different configurations, in each configuration different types of flow of fluids are followed. In this paper single helical tube made of copper is arranged inside the shell like structure and helical baffle. Double pipe helical flow warmth exchanger which is used to transfer warmth or otherwise known as heat is considered as main configuration. The main advantage of the pipe-in-pipe helical flow is more contact on uppermost area for transferring heat as compared with the everyday based pipe-in-pipe exchanger. The performance of this model is analyzed with water in both inlets in same directions and then opposite directions. The inlet, outlet temperatures and flow costs of the both fluids are measured. From the acquired effects, the effectiveness of double helical drift warmth exchanger is sort of 20% extra than the normal double pipe warmness exchanger and it gives warm water output temperature almost 4°C lower than the regular warmthexchanger.

Estimation of power density in IMPATT using different materials

ABSTRACTThe RF output power dissipated per unit area is calculated using Runge-Kutta method for the high-moderate-moderate-high (n+-n-p-p+) doping profile of double drift region (DDR)-based impact avalanche transit time (IMPATT) diode by taking different substrate at Ka band. Those substrates are silicon, gallium arsenide, germanium, wurtzite gallium nitride, indium phosphide and 4H-silicon carbide. A comparative study regarding power dissipation ability by the IMPATT using different material is being presented thereby modelling the DDR IMPATT diode in a one-dimensional structure. The IMPATT based on 4H-SiC element has highest power density in the order of 1010 Wm−2 and the Si-based counterpart has lowest power density of order 106 Wm−2 throughout the Ka band. So, 4H-SiC-based IMPATT should be preferable over others for the power density preference based application. This result will be helpful to estimate the power density of the IMPATT for any doping profile and to select the proper element for the optimum design of the IMPATT as far as power density is concerned in the Ka band. Also, we have focused on variation of power density with different junction temperatures and modelled the heat sink with analysis of thermal resistances.

Apparent motion of double drift target originates from physical location at short delays but from closer to perceived location at longer delays

Apparent motion of double drift target originates from physical location at short delays but from closer to perceived location at longer delays

Modeling and computation of double drift region transit time diode performance based on graphene‐SiC

AbstractWe have proposed a double drift region (DDR) Impact Avalanche Transit Time (IMPATT) diode based on graphene‐silicon carbide (SiC) substrate. Due to attractive and extensive electronics properties of graphene materials, for the first time, we have modeled and designed the diode on epitaxially grown graphene deposited on the silicon face of SiC. The direct current (DC) characteristics and small signal performance of the modeled diode are computed with the help of COMSOL Multi Physics and MATLAB software tools. Performance is evaluated at the frequency regime of Ka band. The proposed diode is validated through the boundary conditions. Profiles of electric field distribution, density of mobile space charge, conversion efficiency, power density, susceptance‐conductance, and voltage drops at different zones are obtained. The graphene‐SiC–based DDR IMPATT is giving better DC and small signal performances.

Simulation on Large Signal and Noise Properties of (n)Si/(p)SiC Heterostructural IMPATT Diodes

Si/SiC heterostructural impact avalanche transit time (IMPATT) diode indicates of important applications in Terahertz (THz) power source, integrated circuit etc. In this paper, the (n)Si/(p)4H-SiC, (n)Si/(p)6H-SiC, (n)Si/(p)3C-SiC heterostructural double drift region IMPATT diodes operating at the atmospheric window frequency of 0.85 THz are designed by the drift-diffusion model while their static state, large signal and noise properties are numerically simulated. The performance parameters of the studied devices such as breakdown voltage, peak electric field strength, optimal negative conductance, output power, power conversion efficiency, admittance-frequency relation, quality factor, noise electric field, mean-square noise voltage per band-width and noise measure were calculated and compared. This method can guide for optimizing the Si/SiC heterostructural IMPATT device in the future.

Quantum corrected drift diffusion based noise model for impact avalanche and transit time diode

We have proposed a quantum corrected drift diffusion based noise model for the more accurate noise computation of double drift region Impact Avalanche Transit Time diode, operating from 26.5 GHz to 40 GHz. Measuring of noise in IMPATT is very difficult task as the noise arises from the generation of electron and hole pairs, due to major effects like hot carriers transport in semiconductor, phonon scattering, inter band scattering of electrons and holes, quantum confinement, quantum tunneling. Conventional classical drift diffusion noise model is independent of these effects. However, in this paper a quantum corrected noise model has been presented in addition to the classical drift diffusion noise model by considering the quantum effects. For the validation of the proposed noise model, silicon has considered as the base material of IMPATT diode. The results obtained from the proposed model are in good agreement with the experimentally measured noise performance and giving better response as compared to that of classical noise model.

Optimization Analysis of Construction Scheme for Large-Span Highway Tunnel Under Complex Conditions

AbstractThe construction process of the tunnel ground deformation regularity of surrounding rock, stability, deformation control of tunnel surface based on the requirements, combined with the characteristics of shallow tunnel with large-span. Used three-dimensional numerical simulation software, established a dynamic tunnel analysis program to simulate the construction process of center cross-diagram method and double sidewall drift method. Based on the stratum deformation, supporting force and analysis of plastic zone distribution, comparative analysis of engineering adaptability of different construction methods from the construction process and construction mechanics, get optimization tunnel construction scheme.

Ka band noise comparison for Si, Ge, GaAs, InP, WzGaN, 4H-SiC-based IMPATT diode

ABSTRACTA comparative study of small signal noise has been presented for n+-n-p-p+ double drift region (DDR) impact avalanche and transit time (IMPATT) diode. The comparison is made by taking different semiconductor materials such as silicon, germanium, gallium arsenide, indium phosphide, wurtzite gallium nitride and 4H-silicon carbide, as doping element throughout the Ka band frequency of 26.5–40 GHz. Also, a generalised idea for performing the small signal noise analysis for the IMPATT diode is presented, by taking a one-dimensional mathematical model of DDR IMPATT diode. The 4H-SiC material-based IMPATT diode is proven to be less noisy with noise measure (NM) variation of 17–29 dB in the Ka band, whereas Ge-based IMPATT diode is noisier with the NM value of 34–44 dB. This paper has studied the small signal noise behaviour and is helpful in selecting the proper semiconducting material for the optimum design of the IMPATT diode in the Ka band.