Extraction of physical Schottky parameters using the Lambert function in Ni/AIGaN/GaN HEMT devices with defined conduction phenomena

Electrical characterization analyses are proposed in this work using the Lambert function on Schottky junctions in GaN wide band gap semiconductor devices for extraction of physical parameters.The Lambert function is used to give an explicit expression of the current in the Schottky junction.This function is applied with defined conduction phenomena,whereas other work presented arbitrary（or undefined）conduction mechanisms in such parameters＇ extractions.Based upon AlGaN/GaN HEMT structures,extractions of parameters are undergone in order to provide physical characteristics.This work highlights a new expression of current with defined conduction phenomena in order to quantify the physical properties of Schottky contacts in AlGaN/GaN HEMT transistors.

The Lambert-G Family:Properties,Inference,and Applications

This study proposes a new flexible family of distributions called the Lambert-G family.The Lambert family is very flexible and exhibits desirable properties.Its three-parameter special sub-models provide all significantmonotonic and non-monotonic failure rates.A special sub-model of the Lambert family called the Lambert-Lomax(LL)distribution is investigated.General expressions for the LL statistical properties are established.Characterizations of the LL distribution are addressed mathematically based on its hazard function.The estimation of the LL parameters is discussed using six estimation methods.The performance of this estimation method is explored through simulation experiments.The usefulness and flexibility of the LL distribution are demonstrated empirically using two real-life data sets.The LL model better fits the exponentiated Lomax,inverse power Lomax,Lomax-Rayleigh,power Lomax,and Lomax distributions.

Solutions for Series of Exponential Equations in Terms of Lambert-W Function and Fundamental Constants

Series of exponential equations in the form of were solved graphically, numerically and analytically. The analytical solution was derived in terms of Lambert-W function. A general numerical solution for any y is found in terms of n or in base y. A solution is close to the fine structure constant. The equation which provided the solution as the fine structure constant was derived in terms of the fundamental constants.

Application of Lambert <i>W</i>Function to Planck Spectral Radiance Frequencies

Planck’s radiation law provides an equation for the intensity of the electromagnetic radiation from a physical body as a function of frequency and temperature. The frequency that corresponds to the maximum intensity is a function of temperature. At a specific temperature, for the frequencies correspond to much less than the maximum intensity, an equation was derived in the form of the Lambert W function. Numerical calculations validate the equation. A new form of solution for the Euler’s transcendental equation was derived in the form of the Lambert W function with logarithmic argument. Numerical solutions to the Euler’s equation were determined iteratively and iterative convergences were investigated. Numerical coincidences with physical constants were explored.

Simplifying the Analysis of Enzyme Kinetics of Cytochrome <i>c</i>Oxidase by the Lambert-W Function

Conventional analysis of enzyme-catalyzed reactions uses a set of initial rates of product formation or substrate decay at a variety of substrate concentrations. Alternatively to the conventional methods, attempts have been made to use an integrated Michaelis-Menten equation to assess the values of the Michaelis-Menten KM and turnover kcat constants directly from a single time course of an enzymatic reaction. However, because of weak convergence, previous fits of the integrated Michaelis-Menten equation to a single trace of the reaction have no proven records of success. Here we propose a reliable method with fast convergence based on an explicit solution of the Michaelis-Menten equation in terms of the Lambert-W function with transformed variables. Tests of the method with stopped-flow measurements of the catalytic reaction of cytochrome c oxidase, as well as with simulated data, demonstrate applicability of the approach to de termine KM and kcat constants free of any systematic errors. This study indicates that the approach could be an alternative solution for the characterization of enzymatic reactions, saving time, sample and efforts. The single trace method can greatly assist the real time monitoring of enzymatic activity, in particular when a fast control is mandatory. It may be the only alternative when conventional analysis does not apply, e.g. because of limited amount of sample.

基于Lambert W函数的太阳电池组件参数提取及优化

为解决太阳电池组件模型精度和参数获取之间的矛盾,提出一种基于Lambert W函数的太阳电池组件参数确定及优化算法。利用Lambert W函数推导出太阳电池组件各参量的解析式,并结合太阳电池组件电压功率模型的最大功率点优化算法提高参量精度。实验表明,该方法不仅可精确获取太阳电池组件各参数值,且可使最大功率点的精度提高到1%以内。

用LambertW函数求解太阳能电池的串联电阻

为准确计算太阳能电池的串联电阻,从太阳能电池单二极管模型的电流-电压特性方程出发,推导出一个用LambertW函数形式表示的串联电阻解析表达式.该表达式仅需将太阳能电池的电流-电压特性曲线和模型参数值代入其中即可求出串联电阻,避免了通常近似计算方法所引入的误差.不同类型和不同工作条件下太阳能电池串联电阻的计算结果验证了文中计算方法的准确性和实用性.

基于Lambert W函数的光伏阵列通用模型研究

以单个光伏电池的电路模型为基础,引入Lambert W函数对光伏电池的I-V方程进行解耦,导出光伏电池电流I关于电压V的显式表达式,并在此基础上建立光伏电池、组件和适用于任意不均匀光照和温度分布情况下光伏阵列的通用数学模型。分析并仿真了串并联光伏阵列在不均匀光照和温度情况下的输出特性曲线及光伏阵列在任意光照强度和温度条件下的输出特性,并说明光照强度分布情况对输出功率曲线峰值点的影响。

基于Lambert W函数的太阳能电池特性仿真

为了得到太阳能电池的最佳工作状态,需要对其各参数进行求解.太阳能电池等效电路模型为电压-电流的隐式方程,无法采用常规方法得到解决.通过引入Lambert W函数,将电流表示成电压的显式方程,并编写程序与牛顿迭代法进行对比,证明了此方法的正确性与精确性.模拟仿真发现串联电阻与并联电阻对太阳能电池的伏安特性和输出功率等特性曲线有较大影响,且影响效果各不相同,但共同影响着输出电压与功率等参数.

基于Lambert W函数的装备经济寿命分析

为改进现有装备经济寿命模型求解时计算量大、不便于分析等缺点,提出了一种新的装备经济寿命确定方法。首先通过Lambert W函数求解出装备经济寿命的精确计算解析式,其次采用多项式拟合、有理拟合对Lambert W函数进行精确估算,并将结果与Lambert W函数近似解和精确解进行比较,在此基础上得出了装备经济寿命的精确估算公式。实验表明,估算公式是一个分段函数形式,对经济寿命的估算精度可控制在±1年。该方法与传统的列表法相比,不仅具有直观性,利于掌握和计算,同时便于进一步分析经济寿命的影响因素和变化规律。

太阳电池Ⅰ-Ⅴ方程的LambertW函数解

用LambertW函数求解太阳电池的I-V方程.推导出了由实测数据计算并联电阻、串联电阻和I-V曲线的方法.

Lambert W函数性质及其应用

介绍了Lambert W函数的代数及图像性质,如该函数的级数展开式、微分及函数在复平面的图像等。总结了其在数学、物理、化学和生物等领域的应用情况。

基于偏心率向量含约束多圈Lambert问题

讨论了带工程约束条件的多圈Lambert轨道问题。基于Lambert问题中偏心率向量沿转移弦线不变性,使用偏心率向量的横向分量作为解算的迭代变量,分析了工程约束函数的特性,并根据约束函数特性,直接从多圈Lambert问题的多个解中解算出满足约束条件的解,避免了后期的比较筛选。提出的方法,求解次数更少,解算过程更为直接,最后给出的数值算例验证了方法的准确性与有效性。

Gamma Approximation Based Multi-Antenna Covert Communication Detection

Covert communication technology makes wireless communication more secure,but it also provides more opportunities for illegal users to transmit harmful information.In order to detect the illegal covert communication of the lawbreakers in real time for subsequent processing,this paper proposes a Gamma approximation-based detection method for multi-antenna covert communication systems.Specifically,the Gamma approximation property is used to calculate the miss detection rate and false alarm rate of the monitor firstly.Then the optimization problem to minimize the sum of the missed detection rate and the false alarm rate is proposed.The optimal detection threshold and the minimum error detection probability are solved according to the properties of the Lambert W function.Finally,simulation results are given to demonstrate the effectiveness of the proposed method.

FaultMonitoring Strategy for PV System Based on I-V Feature Library

Long-term use in challenging natural conditions is possible for photovoltaic modules,which are extremely prone to failure.Failure to diagnose and address faults in Photovoltaic(PV)power systems in a timely manner can cause permanent damage to PV modules and,in more serious cases,fires.Therefore,research into photovoltaic module defect detection techniques is crucial for the growth of the photovoltaic sector as well as for maintaining national economic prosperity and ensuring public safety.Considering the drawbacks of the current real-time and historical data-based methods for monitoring distributed PV systems,this paper proposes a method for monitoring PV systems at the module or string level that can be achieved by monitoring only electrical signals.The approach doesn’t need a lot of tests to get the operational data of PV modules beforehand and only requires theoretical feature libraries of PV modules through panel parameter calculations.The present operating conditions and the open-circuit and short-circuit faults can be precisely identified by comparing the observed open-circuit voltage and short-circuit current with the corresponding data in the theoretical feature library.After that,by comparing the measured maximum power point voltage and current with the corresponding data in the theoretical feature library through the threshold method,aging and shadowing faults can be accurately determined.Experimental testing was done to see whether the suggested method was effective.The results show that the proposed technique is able to diagnose open-circuit faults,short-circuit faults,aging faults,and shadowing faults with shadow occlusion above 20%.

多约束下考虑控制饱和的自适应末制导方法

对地攻击飞行器在末制导过程中需满足导引头视场、攻角、落角等多种约束。针对这一问题提出一种多约束下的制导方法。将多约束下的制导问题转化为具有控制饱和的线性系统的镇定问题。针对该问题,利用基于参量Lyapunov方程的低增益反馈设计方法,推导带低增益参数的纵向制导律。借助Lambert W函数,研究闭环系统状态收敛特性与低增益参数的关系,给出低增益参数的自适应整定方法。通过该方法在线调整参数,使各约束条件得到满足。通过数值仿真对提出的制导方法进行校验。仿真结果表明,提出的制导方法满足约束条件且获得较高的制导精度。

光伏电池参数求解与最大功率点基准值的研究

文章基于光伏电池的I-V和P-V输出特性,利用Lambert W函数,提出了一种新型求解光伏电池模型参数的算法,并给出在任意光照强度和温度下,光伏系统最大功率点基准值和最基准曲线的方法。最后与实测数据仿真比较,验证了所提参数求解方法的准确性以及对基准值分析的有效性。

基于OP/FTIR和反射转镜式干涉光谱仪的大气CO2浓度测量

对地球大气温室气体进行高精度的探测,是当今数值天气预报和气候与大气环境变化监测的发展需求。利用OP/FTIR测量法,将一台国内率先自行研制的中波红外反射转镜式干涉光谱仪,首次成功地用于地表大气CO2红外吸收光谱的测量。该反射转镜式干涉光谱仪的工作谱段为2 100~3 150cm-1,光谱分辨率为2cm-1。设计了大气成分探测方法,建立了大气浓度参数反演数理依据和定量分析算法。采用基于比尔定律的直接法和基于HITRAN数据库及仪器函数的仿真拟合法,建立了反演模型,并对CO2分子的浓度进行了反演。根据观测和模型分析,CO2的浓度反演结果在300~370ppm,呈现出随自然环境变化先缓慢降低再快速升高的趋势,并在下午至傍晚之间达到低值;同时,随时间的变化,用直接法计算的CO2浓度和用拟合法的仿真值表现出了良好的一致性,所有测量数据之间的相关性高达99.79%,相对误差不超过2.00%,达到了较高的反演精度。结果表明,在遥感测量大气成分方面,基于红外反射转镜式干涉光谱仪的OP/FTIR法是可行且有效的技术手段,直接法或拟合法皆可实现高精度的浓度反演。

一类时滞系统Hurwitz稳定的简单判据

近年来,Lambert W函数已被成功的应用到时滞系统的稳定性分析中。但由于Lambert W函数是一个超越方程的解,而且它的求解需要借助数学软件Maple,Matlab或Mathematica才能完成,因此在理解和应用上都有一定困难。本文通过深入研究,首先利用初等函数描述了Lambert W函数根的分布情况,进而给出了一类时滞系统渐近稳定和鲁棒稳定的简单判据。利用新的判据,原来可以用Lambert W函数来判定的时滞系统的稳定性问题,现在只需要用初等函数就可以解决。

多用户大规模MIMO系统能效资源优化算法

针对多用户下行大规模MIMO系统,为满足用户QoS需求,建立关于发射功率、发射天线数、用户天线数的系统能效优化模型。区别于传统的利用迭代算法求解使系统能效最佳的发射功率,提出采用Lambert W函数分析得到系统最佳发射功率的闭式表达式,极大地降低了运算复杂度。并利用天线选择算法进一步对能效进行优化,即采用凸优化算法对能效进行优化。仿真结果表明,所提算法能有效提高系统能效,提升系统性能。