Determination of the Series Resistance of a Series Vertical-Junction Silicon (N+/P/P+) Solar Cell under Polychromatic Illumination and Magnetic Field: Effect of Optimum Thickness

By solving the magneto-transport equation for excess minority charge carriers in the base of the series vertical-junction silicon cell, the phenomenological parameters of the cell can be determined from the boundary conditions. Photocurrent density and photovoltage are determined for each value of applied magnetic field and corresponding optimum thickness, to establish the current-voltage characteristic (Jph(Sf, Sb, z, B, Hop)-Vph(Sf, Sb, z, B, Hop) of the silicon cell under polychromatic illumination. This study will make it possible to reduce the material used (by reducing the optimum thickness), which will help to lower prices. It will also enable us to reduce betting effects (lower series resistance), thereby boosting solar cell efficiency.

Numerical Prediction of Added Resistance and Vertical Ship Motions in Regular Head Waves

The numerical prediction of added resistance and vertical ship motions of one ITTC （Intemational Towing Tank Conference） S-175 containership in regular head waves by our own in-house unsteady RANS solver naoe-FOAM-SJTU is presented in this paper. The development of the solver naoe-FOAM-SJTU is based on the open source CFD tool, OpenFOAM. Numerical analysis is focused on the added resistance and vertical ship motions （heave and pitch motions） with four very different wavelengths （ 0.8Lpp 〈 2 〈 1.5L ） in regular head waves. Once the wavelength is near the length of the ship model, the responses of the resistance and ship motions become strongly influenced by nonlinear factors, as a result difficulties within simulations occur. In the paper, a comparison of the experimental results and the nonlinear strip theory was reviewed and based on the findings, the RANS simulations by the solver naoe-FOAM-SJTU were considered competent with the prediction of added resistance and vertical ship motions in a wide range of wave lengths.

Low specific on-resistance GaN-based vertical heterostructure field effect transistors with nonuniform doping superjunctions

A novel Ga N-based vertical heterostructure field effect transistor（HFET） with nonuniform doping superjunctions（non-SJ HFET） is proposed and studied by Silvaco-ATLAS,for minimizing the specific on-resistance（RonA） at no expense of breakdown voltage（BV）.The feature of non-SJ HFET lies in the nonuniform doping concentration from top to bottom in the n-and p-pillars,which is different from that of the conventional Ga N-based vertical HFET with uniform doping superjunctions（un-SJ HFET）.A physically intrinsic mechanism for the nonuniform doping superjunction（non-SJ） to further reduce RonA at no expense of BV is investigated and revealed in detail.The design,related to the structure parameters of non-SJ,is optimized to minimize the RonA on the basis of the same BV as that of un-SJ HFET.Optimized simulation results show that the reduction in RonA depends on the doping concentrations and thickness values of the light and heavy doping parts in non-SJ.The maximum reduction of more than 51% in RonA could be achieved with a BV of 1890 V.These results could demonstrate the superiority of non-SJ HFET in minimizing RonA and provide a useful reference for further developing the Ga N-based vertical HFETs.

Mathematical analysis of drug resistance in vertical transmission of HIV/AIDS

A nonlinear mathematical model of vertical transmission of HIV/AIDS is proposed to study the effects of drug resistance in the spread of the disease. The study assumes that treatment leads to the evolution of drug resistance in some pockets of the population. We use traditional methods to determine conditions for existence and stability of disease-free and endemic equilibrium points of the model. The study showed that the burden of the disease may be reduced if the reproduction number is reduced below unity and may persist if the reproduction number is raised above unity. Furthermore, evolution of drug resistance due to treatment may change the cause of the epidemic.

Impact of Parasitic Resistances on the Output Power of a Parallel Vertical Junction Silicon Solar Cell

This paper describes the theoretical model for calculating IV-curve of parallel vertical silicon solar cells (SCs) based on solving diffusion-recombination equation for such SC, which was suggested that two IV curve zones (those which are close to the short current and open circuit points) can be linearized. This linearalization allows obtaining the values of shunt (Rsh) and series (Rs) resistances. The evolution of the electric power based on these resistances was illustrated to show the values that shunt and series resistances must have to obtain a good efficiency.

Modeling of resistance characteristics of a continuously-graded distributed Bragg reflector in a 980-nm vertical-cavity surface-emitting laser

The resistance characteristics of a continuously-graded distributed Bragg reflector（DBR） in a 980-nm verticalcavity surface-emitting laser（VCSEL） are modeled in detail.The junction resistances between the layers of both the p-and n-DBR mirrors are analysed by combining the thermionic emission model and the finite difference method.In the meantime,the intrinsic resistance of the DBR material system is calculated to make a comparison with the junction resistance.The minimal values of series resistances of the graded p-and n-type DBR mirrors and the lateral temperature-dependent resistance variation are calculated and discussed.The result indicates the potential to optimize the design of the DBR reflectors of the 980-nm VCSELs.

Elastoplastic solutions for single piles under combined vertical and lateral loads

In order to improve the reliability of the design and calculation of single piles under the combined vertical and lateral loads, the solutions were presented based on the subgrade reaction method, in which the ultimate soil resistance was considered and the coefficient of subgrade reaction was assumed to be a constant. The corresponding computational program was developed using FORTRAN language. A comparison between the obtained solutions and the model test results was made to show the validity of the obtained solutions. The calculation results indicate that both the maximum lateral displacement and bending moment increase with the increase of the vertical and lateral loads and the pile length above ground, while decrease as the pile stiffness, the coefficient of subgrade reaction and the yielding displacement of soil increase. It is also shown that the pile head condition controls the pile responses and the vertical load may cause the instability problem to the pile. In general, the proposed method can be employed to calculate the pile responses independent of the magnitude of the pile deflection.

给定k个悬挂点的单圈图的极大Resistance-Harary指数

Resistance-Harary指数是指连通图G中所有点对之间的电阻距离的倒数之和,即RH(G)=∑{u,v}■V(G)1/(r_G(u,v)),其中r_G(u,v)是指连通图中任意两点u、v之间的电阻距离。主要研究给定k个悬挂点的n阶单圈图的Resistance-Harary指数的极大图类。

Image Reconstruction for Invasive ERT in Vertical Oil Well Logging

An invasive electrical resistance tomographic sensor was proposed for production logging in vertical oil well.The sensor consists of 24 electrodes that are fixed to the logging tool,which can move in the pipeline to acquire data on the conductivity distribution of oil/water mixture flow at different depths.A sensitivity-based algorithm was introduced to reconstruct the cross-sectional images.Analysis on the sensitivity of the sensor to the distribution of oil/water mixture flow was carried out to optimize the position of the imaging cross-section.The imaging results obtained using various boundary conditions at the pipe wall and the logging tool were compared.Eight typical models with various conductivity distributions were created and the measurement data were obtained by solving the forward problem of the sensor system.Image reconstruction was then implemented by using the simulation data for each model.Comparisons between the models and the reconstructed images show that the number and spatial distribution of the oil bubbles can be clearly identified.

Improvement of reverse blocking performance in vertical power MOSFETs with Schottky–drain-connected semisuperjunctions

To enhance the reverse blocking capability with low specific on-resistance,a novel vertical metal-oxidesemiconductor field-effect transistor（MOSFET） with a Schottky-drian（SD） and SD-connected semisuperjunctions（SDD-semi-SJ）,named as SD-D-semi-SJ MOSFET is proposed and demonstrated by two-dimensional（2D） numerical simulations.The SD contacted with the n-pillar exhibits the Schottky-contact property,and that with the p-pillar the Ohmic-contact property.Based on these features,the SD-D-semi-SJ MOSFET could obviously overcome the great obstacle of the ineffectivity of the conventional superjunctions（SJ） or semisuperjunctions（semi-SJ） for the reverse applications and achieve a satisfactory trade-off between the reverse breakdown voltage（BV） and the specific on-resistance（R_（on）A）.For a given pillar width and n-drift thickness,there exists a proper range of n-drift concentration（N）,in which the SD-D-semi-SJ MOSFET could exhibit a better trade-off of R_（on）A-BV compared to the predication of SJ MOSFET in the forward applications.And what is much valuable,in this proper range of N,the desired BV and good trade-off could be achieved only by determining the pillar thickness,with the top assist layer thickness unchanged.Detailed analyses have been carried out to get physical insights into the intrinsic mechanism of R_（on）A-BV improvement in SD-D-semi-SJ MOSFET.These results demonstrate a great potential of SD-D-semi-SJ MOSFET in reverse applications.

Vertical Electrical Sounding of Water-Bearing Sub-Surface of Issele-Azagba in Southern Nigeria

An electrical resistivity survey involving vertical electrical sounding (VES) technique was carried out in Issele-Azagba, Aniocha North Local Government Area of Delta State, Nigeria. This was aimed at investigating the lithologic boundaries and classification of the various subsurface formations. The data obtained were subjected to a twofold interpretative procedure involving initial partial curve matching and computer iteration. Results showed that a maximum of five subsurface layers was delineated from the geoelectric sections. This is made up of loamy topsoil underlain by relatively continuous sandy units composed of different compaction, wetness and clay content. The result also showed that the fifth substratum of the geoelectric section was the aquiferous sand relevant in groundwater development within the study area. Analysis of the result had shown that the aquifers identified in this study were vulnerable contamination percolating from the surface due to the absence of a protective aquitards.

Power Law Exponents for Vertical Velocity Distributions in Natural Rivers

While log law is an equation theoretically derived for near-bed region, in most cases, power law has been researched by experimental methods. Thus, many consider it as an empirical equation and fixed power law exponents such as 1/6 and 1/7 are generally applied. However, exponent of power law is an index representing bed resistance related with relative roughness and furthermore influences the shapes of vertical velocity distribution. The purpose of this study is to investigate characteristics of vertical velocity distribution of the natural rivers by testing and optimizing previous methods used for determination of power law exponent with vertical velocity distribution data collected with ADCPs during the years of 2005 to 2009 from rivers in South Korea. Roughness coefficient has been calculated from the equation of Limerinos. And using theoretical and empirical formulae, and representing relationships between bed resistance and power law exponent, it has been evaluated whether the exponents suggested by these equations appropriately reproduce vertical velocity distribution of actual rivers. As a result, it has been confirmed that there is an increasing trend of power law exponent as bed resistance increases. Therefore, in order to correctly predict vertical velocity distribution in the natural rivers, it is necessary to use an exponent that reflects flow conditions at the field.

The Effects of a Complex Training Protocol on Vertical Jump Performance in Male High School Basketball Players

The purpose of this study was to investigate the effects of CT （complex training） on VJ （vertical jump）. It was hypothesized that VJ height would be enhanced through CT and even greater increases would occur as a result of higher intensity resistance exercise. Twenty male high school basketball players were divided into two training groups： a H1 （high intensity）, low repetition group and a medium intensity, HR （high repetition） group. Each training group trained twice per week for six weeks. Training protocols involved three sets of 8-10 squat repetitions （80%-85% 1RM （repetition maximum）） for the HI group followed by ten countermovement jumps and thre.e sets of 12-15 squat repetitions （60%-70% 1RM） for the HR group followed by ten countermovement jumps. A three minute rest period was utilized between each set. Participants were tested at weeks 1, 3, and 6. The results of this study revealed that there was not a significant difference between the two CT protocols with respect to VJ （p = 0.077）. At week 6 both groups increased VJ significantly; HI group （4.0 ±1.8 cm, p 〈 0.01） and the HR group （2.7 ± 1.6 cm, p 〈 0.01）. Within the parameters of this study CT with either HI or HR protocols are effective at improving VJ.

High-voltage SOI lateral MOSFET with a dual vertical field plate

A new silicon-on-insulator （SOI） power lateral MOSFET with a dual vertical field plate （VFP） in the oxide trench is proposed. The dual VFP modulates the distribution of the electric field in the drift region, which enhances the internal field of the drift region and increases the drift doping concentration of the drift region, resulting in remarkable improvements in breakdown voltage （BV） and specific on-resistance （Ron,sp）. The mechanism of the VFP is analyzed and the characteristics of BV and Ron,sp are discussed. It is shown that the BV of the proposed device increases from 389 V of the conventional device to 589 V, and the Ron,sp decreases from 366 mΩ·cm2 to 110 mΩ·cm2.

基于垂直四探针的晶圆检测装置设计及应用

半导体晶圆在国防、光电器件等领域有广泛应用,针对晶圆检测过程中由于电阻率分布不均匀导致的精度低等问题,提出研制一种完全国产化四探针晶圆检测装置,并对其探针压力对电阻率的影响展开研究。首先,引入探针压力为变量,构建基于开尔文的垂直四探针载流子扩散流密度模型;其次,对整机进行设计,采用LK-G5000激光传感器检测导轨和转台的运动精度验证检测平台精度;最后,通过标定最佳压入深度区间段的压电与压入深度之间的关系后验证检测装置性能。实验结果表明,在(23±1)℃,湿度55%RH下,探针预热后针温稳定时电阻率分布稳定、均匀,其电阻率均值误差稳定在3.397%,标准偏差在2.865%,达到检测指标。

Fault detection using microtremor data (HVSR-based approach) and electrical resistivity survey

The faults and fractures are known as two of the most important parameters in earthquake occurrence.During the construction in urban areas, faults and fractures may be covered in depth and thus are not visible at the ground surface. In this context, non-invasive geophysical prospecting methods(microtremor and geoelectrical methods) and borehole data were used to detect subsurface geological structures(hidden faults) in a suburb of Shiraz in Iran. The horizontal to vertical spectral ratio(HVSR) method was used to obtain the dynamic parameters(predominant frequency and resonance amplitude) of the soil, to detect hidden faults. The results show that the abrupt changes in the sediment thickness and predominant frequencies at a specific direction(NW-SE) can be related to the displacement of a nearly vertical fault with NW-SE trend. In addition, the electrical resistivity method using continuous resistivity profiling(CRP) and Schlumberger arrays was employed to detect a hidden fault and the results were compared with previous data. The obtained results of both arrays illustrate the presence of a nearly vertical fault with NW-SE trend in the region. Comparison of all results shows that the detected faults by both methods are consistent with each other. Therefore, it can be conclusive that combination of the two methods is a useful and reliable approach to study and detect hidden faults.

Electrical Resistivity Survey for Predicting Aquifer at Onicha-Ugbo, Delta State, Nigeria

A geoelectric survey employing the vertical electrical sounding (VES) was carried out in parts of Onicha-Ugbo in Aniocha North Local Government Area of Delta State using Abem Terrameter SAS 300C together with SAS 2000 booster. The study was carried out with the aim of delineating the subsurface geologic sequence present in the study area, determining their geoelectrical parameters (layer thicknesses and resistivities), and delineating the structural and geomorphological features present beneath the subsurface. The results of the survey suggest that the subsurface comprises of 5 - ?6 layers and that clay and silt content varies vertically and horizontally, thus influencing the apparent resistivity of the area. The geoelectric section developed shows that the subsurface units are dominantly sandy underlying loamy sandy topsoil which is relatively dry. The depth to water table from the sites is above 150 m and suggests that groundwater exploration is encouraging.

Ultralow specific ON-resistance high-k LDMOS with vertical field plate

An ultralow specific on-resistance high-k LDMOS with vertical field plate（VFP HK LDMOS） is proposed. The high-k dielectric trench and highly doped interface N＋ layer are made in bulk silicon to reduce the surface field of the drift region in the VFP HK LDMOS. The gate vertical field plate（VFP） pinning in the high-k dielectric trench can modulate the bulk electric field. The high-k dielectric not only provides polarized charges to assist depletion of the drift region, so that the drift region and high-k trench maintain charge balance adaptively,but also can fully assist in depleting the drift region to increase the drift doping concentration and reshape the electric field to avoid premature breakdown. Compared with the conventional structure, the VFP HK LDMOS has the breakdown voltage of 629.1 V at the drift length of 40 μm and the specific on-resistance of 38.4 mΩ·cm^2 at the gate potential of 15 V. Then the power figure of merit is 10.31 MW/cm^2.

Electrical Resistivity Sounding for Groundwater Investigation around Enugu Metropolis and the Environs, Southeast Nigeria

This report evaluates the use of electrical method and borehole data to investigate the subsurface to delineate the groundwater potential in Enugu metropolis and the environs, south-eastern Nigeria other than rely only on resistivity method which could lead to interpretation error. Integrating these 2 data sets is key in this study. The study area is located in the Anambra Basin and is underlain by Nkporo/Enugu Shale which is overlain by the Mamu Formation. It is bounded by Latitudes 6°2 0'00"N to 6°30'00"N and Longitudes 7°25'00"E to 7°35'00"E and covers surface area of about 342 m2. Thirty-one vertical electrical soundings (VES) were carried out across the area using the Schlumberger electrode array with current electrode separation from 2 to 500 m to identify the depths and resistivity values of the identified geo-electric layers. Through data analysis using WinResist software, the apparent resistivity, thicknesses and depths and the thicknesses of the aquifers were generated. The resistivity and depths were modelled to generate resistivity map and depth map. The resistivity of the aquiferous zone within the study area varied from 20.55 - 427.8 ohm-m at depths of between 10.7 - 40.05 m. Depth to the water table appears to be shallow at the south western part of the map. The interpreted geo-electric layers show a sequence of lateritic top soil, shale, sand and shale. The frequency distribution of the VES curves generated shows the presence of 3 to 5 layers with HK type as the highest. Also, a 2D model was generated using the correlation of VES to VES data and borehole data to VES data to show the underlying stratigraphy beneath the study area as well as the direction of ground water flow. Result of the VES curve analysis reveals that the sub-surface is underlain by three lithological layers namely: lateritic top soil, shale, sand and shales with NW direction of groundwater flow from the 2D model. Groundwater prospective zones can be seen along NW, SW and central parts of the study area which have low resistivity values.

Groundwater Potential Mapping in Lapan Gwari Community Using Integrated Remote Sensing and Electrical Resistivity Soundings

This research aims to address the pressing issue of failed and abandoned wells, causing water scarcity in Lapan Gwari Community, through an improved groundwater exploration approach integrating remote sensing and electrical resistivity soundings. The study area, located within the Zungeru Sheet 163 SE, spans Latitudes 9°30'00"N to 9°32'00"N and Longitudes 6°28'00" to 6°30'00". The surface geologic, structural, and hydrogeological mapping provided essential insights into the hydrogeological framework. Leveraging SRTM DEM data, thematic maps were created for geomorphology, slope, land use, lineament density, and drainage density. These datasets were then integrated using ArcGIS to develop a preliminary groundwater potential zones map. Further investigations were conducted using Vertical Electrical Sounding (VES) and Electrical Resistivity Imaging (2D VES) surveys at targeted locations identified by the preliminary map. Results show that the study area predominantly consists of crystalline rocks of the Nigerian Basement Complex, primarily comprising schist and granite with minor occurrences of quartz vein intrusions. Surface joint directions indicated a dominant NE-SW trend. The VES data revealed three to four geoelectric layers, encompassing the topsoil (1 to 5 m depth, resistivity: 100 Ωm to 300 Ωm), the weathered layer (in the 3-layer system) or fractured layer (in the 4-layer system), and the fresh basement rock characterized by infinite resistivity. The shallow weathered layers (3 to 30 m thickness) are believed to hold aquiferous potential. Hydrogeological interpretation, facilitated by 2D resistivity models, delineated water horizons trapped within clayey sand and weathered/fractured formations. Notably, the aquifer resistivity range was found to be between 3 - 35 m and 100 - 300 Ωm, signifying a promising aquifer positioned at depths of 40 to 88 m. This aligns with corroborative static water level measurements. Given this, we recommend drilling depths of a minimum of 80 m to ensure the acquisition of sufficient and sustainable water supplies. The final groundwater potential zones map derived from this study is expected to serve as an invaluable guide for prospective groundwater developers and relevant authorities in formulating effective water resource management plans. By effectively tackling water scarcity challenges in Lapan Gwari Community, this integrated approach demonstrates its potential for application in similar regions facing comparable hydrogeological concerns.