ESTIMATE ON THE BLOCH CONSTANT FOR CERTAIN HARMONIC MAPPINGS UNDER A DIFFERENTIAL OPERATOR

In this paper,we first obtain the precise values of the univalent radius and the Bloch constant for harmonic mappings of the formL(f)=zfz-zfz,where f represents normalized harmonic mappings with bounded dilation.Then,using these results,we present better estimations for the Bloch constants of certain harmonic mappings L(f),where f is a K-quasiregular harmonic or open harmonic.Finally,we establish three versions of BlochLandau type theorem for biharmonic mappings of the form L(f).These results are sharp in some given cases and improve the related results of earlier authors.

WIDELY LINEAR RLS CONSTANT MODULUS ALGORITHM FOR COMPLEX-VALUED NONCIRCULAR SIGNALS

Based on the constant modulus criterion, a new Widely Linear(WL) blind equalizer and a novel widely linear recursive least square constant modulus algorithm are proposed to improve the blind equalization performance for complex-valued noncircular signals. The new algorithm takes advantage of the WL filtering theory by taking full use of second-order statistical information of the complex-valued noncircular signals. Therefore, the weight vector contains the complete second-order information of the real and imaginary parts to decrease the residual inter-symbol interference effectively. Theoretical analysis and simulation results show that the proposed scheme can significantly improve the equalization performance for complex-valued noncircular signals compared with traditional blind equalization algorithms.

Linear fast shutdown technology based on self-resonant constant voltage clamping

Transient electromagnetic method(TEM)has been widely used in the field of medium and shallow underground detection due to its high detection efficiency and large detection depth.However,due to the long turn-off time of the transmitting current caused by the inductive characteristics of the transmitting coil,the early signals will be overwhelmed by primary field.Since the early signals contain most of shallow geological signals,it is necessary to reduce the long turn-off time to get shallow layer signal.Due to lack of a reliable and effective clamping method for high-power transmission at present,we design a TEM transmitter fast turn-off circuit,combining self-resonant zero-voltage switching technology with the corresponding timing control circuit to solve this problem effectively.A transient electromagnetic transmitter based on self-resonant constant voltage clamping technology was fabricated to charge the clamping capacitor.The rated transmitting current of the transmitter is 20 A,and the turn-off time is continuously adjustable from 550-50μs.Moreover,the current drop process is approximately linear rather than exponential attenuation.Compared with the existing clamping methods,the proposed clamping method solves the problems that transient voltage suppressor(TVS)clamping cannot be used in high-power occasions and has a high failure rate.It also solves the problem of long pre-charge time in traditional capacitor clamping methods due to insufficient inductance of the small size transmitting coil.The proposed method can provide a reference for fast shutdown of large current.

Determination of Compositions and Stability Constants of Holmium and Yttrium Complexes with Tribromoarsenazo by Linear Regression Method

According to the appearing of isosbestic point in the absorption spectra of Ho/Y-Tribromoarsenazo (TBA)systems,the complexation reaction is considered to be M+nL=ML_n.A method has been proposed based on it for calculating the mole fraction of free complexing agent in the solutions from spectral data.and two linear regression formula have been introduced to determine the composition,the molar absorptivity,the conditional stability constant of the complex and the concentration of the complexing agent. This method has been used in Ho-TBA and Y-TBA systems.Ho^(3+)and Y^(3+)react with TBA and form 1: 2 complexes in HCl-NaAc buffer solution at pH 3.80.Their molar absorptivities determined are 1.03×10~8 and 1.10×10~8 cm^2·mol^(-1),and the conditional stability constants(logβ_2)are 11.37 and 11.15 respectively.After considering the pH effect in TBA complexing,their stability constants(log β_2^(ahs))are 43.23 and 43.01. respectively.The new method is adaptable to such systems where the accurate concentration of the complexing agent can not be known conveniently.

Determination of Composition and Stability Constant of Praseodymium(Pr^(3+))Complex with Tribromoarsenazo(TBA)by Dual-Series Linear Regression Method

A new method,dual-series linear regression method,has been used to study the complexation equilibrium of praseodymium(Pr^(3+))with tribromoarsenazo(TBA)without knowing the accurate concentra- tion of the complexing agent TBA.In 1.2 mol/L HCl solution, Pr^(3+)reacts with TBA and forms 1:3 com- plex,the conditional stability constant(lgβ_3)of the complex determined is 15.47,and its molar absorptivity(ε_3^(630))is 1.48×10~5 L·mol^(-1)·cm^(-1).

Widely linear UKF constant modulus algorithm for blind adaptive beamforming

Based on a uniform linear array, a new widely linear unscented Kalman filter-based constant modulus algorithm (WL-UKF-CMA) for blind adaptive beamforming is proposed. The new algorithm is designed according to the constant modulus criterion and takes full advantage of the noncircular property of the signal of interest (SOI), significantly increasing the output signal-to interference-plus-noise ratio (SINR), enhancing the convergence speed and decreasing the steady-state misadjustment. Since it requires no known training data, the proposed algorithm saves a large amount of the available spectrum. Theoretical analysis and simulation results are presented to demonstrate its superiority over the conventional linear least mean square-based CMA (L-LMS-CMA), the conventional linear recursive least square-based CMA (L-RLS-CMA), WL-LMS-CMA, WL-RLS-CMA and L-UKF-CMA.

Criteria for the Degree of Stability of the Linear Constant Systems

There are various applications of the stability theory of the first-order dynamical systems. And the stability of the non-linear control systems can be determined by its linear part. In practice, it is not enough to know the stability of the dynamical systems. Sometimes we must know the degree of stability of these systems. In this paper, we present some criteria for the degree of stability of the linear constant systems, by using the entries of the coefficient matrix A only.

THE LINEAR CORRELATIONS BETWEEN ELECTRONIC TRANSITION ENERGY AND HAMMETT CONSTANTS FOR THE SUBSTITUTED PORPHYRIN-LIKE MACROCYCLE

The properties of absorption spectra are presented and the linear correlations of Hammett constants with the 0-0 transition energy(E_(o,o))of S_←S_o, and the ratios of oscillator strength(f/f)are used to probe the interactions betwee π-electron of aromatic maerocycles or metal ion of complexes with the sub- stituents on β-position of benzene ring for porphyrin-like maerocyclic compounds.

A Production Inventory Model of Constant Production Rate and Demand of Level Dependent Linear Trend

The proposed model considers the products with finite shelf-life which causes a small amount of decay. The market demand is assumed to be level dependent and in a linear form. The model has also considered the constant production rate which stops attaining a desired level of inventories and that is the highest level of inventories. Production starts with a buffer stock and without any sort of backlogs. Due to the market demand and product’s decay, the inventory reduces to the level of buffer stock where again the production cycle starts. With a numerical search procedure the proof of the proposed model has been shown. The objective of the model is to obtain the total average optimum inventory cost and optimum ordering cycle.

一类带有分段常数变元的线性时滞微分方程的振动判据

针对一类带有分段变元的线性时滞微分方程,在系数缓慢变化的情形下,利用Bolzano-Weierstrass定理,建立判定其振动性的充分条件,将已有的下极限型条件改进为上极限型条件,进而可以判定部分原先所不能判定的方程的振动性,并采用2个例子证明其有效性。

基于线性自抗扰的车载蓄电池电机车充电系统

针对传统矿用蓄电池电机车充电过程繁琐,需将蓄电池从电机车上吊离至专用充电机房充电,再吊回至电机车,这种充电方式要求有多套蓄电池进行替换,效率低下,并且充电纹波大、质量差。对此设计了一种蓄电池电机车车载充电控制系统,采用PWM整流和DC/DC变换两级式拓扑结构,对前级PWM整流器电压外环用线性自抗扰控制,内环采用电流解耦控制,对后级双向DC/DC采用恒流转恒压的双闭环控制。实验结果表明,基于线性自抗扰的车载充电控制系统在提升充电效率的同时,能够有效降低母线电压纹波、减小网侧电流畸变,提高充电质量。

基于多频段拼接的高分辨率太赫兹成像技术

为解决带宽限制导致的太赫兹调频连续波成像纵向分辨率低的问题,提出一种适用于线性调频体制的多频段拼接的方法。该方法基于参考信号的非线性补偿算法,改进传统宽带时域合成算法,在非线性校正的同时实现各频段信号频率和相位上的连续性,无需再进行频移和相位补偿。搭建0.11~0.75 THz 5个频段线性调频成像系统进行实验验证,结果表明,该方法显著提高太赫兹成像纵向分辨率,同时提高材料介电常数测试精度,未来可应用于材料测试领域。此外,设计了表面台阶型样品和多层胶粘的内部缺陷样品进行成像,证明融合信号的图像包含更多的细节,样品的每一层分离得更为明显,高度差仅0.2 mm也能清晰地分辨,能够满足高精度无损检测的需求。

韦达定理在推导常系数齐次线性微分方程通解式中的应用

在探讨常系数齐次线性微分方程的通解时,通常侧重于通过求解代数方程即特征方程来找到方程的根,进而构建出通解.提出一种利用韦达定理来直接推导出这种微分方程通解形式的方法.通过利用韦达定理建立方程的系数与其根之间的直接联系,从而更为直观地构造出微分方程的通解.该方法为求解此类问题提供了一种新的思路.

玻璃磨边加工中抛光轮半径磨损补偿方法

根据抛光轮磨损的特性,采用阿基米德螺线模型,控制抛光轮相对工件以恒定线速度运动,同时不同材质的抛光轮按照对应恒定的磨损率磨损,利用累计的加工轨迹长度与磨损率计算抛光轮实时半径值,实现半径磨损补偿。实验结果证明该方法有效,在加工全过程中能保持稳定良好的抛光效果。

一种稳健恒定束宽宽波束形成算法

传统宽带波束形成算法在导向矢量失配时输出性能下降,为解决该问题,文章提出一种稳健恒定束宽波束形成算法。该算法首先构造与快拍数相关的对角加载函数;其次,基于空域积分思想,结合入射信号的方向误差范围估计期望信号的实际入射方向,并结合构造的对角加载系数生成优化波束加权系数;最后,联合优化后的波束权值与FIR滤波器系数完成宽带波束响应的全局优化设计。经仿真实验验证,相比于传统分布设计法的时域宽带波束形成,文中方法可以得到较理想的恒定宽带主瓣响应和较低的旁瓣电平,同时在期望信号导向矢量失配情况下,仍有较好的输出信干噪比。

一种实现均匀线列阵恒定束宽的方法

当基阵接收信号为宽带时,若采用常规宽带波束形成,不同频率上波束图不同,频率越高,波束宽度越窄。当信号从波束主瓣内非主轴方向入射时,输出波形会发生失真,直接影响到后续的一系列功能,如系统估计波形、识别目标特性等。该问题的基本解决方法是,设计恒定束宽波束形成器,使基阵系统对不同频率的输入信号具有相似的波束图。研究了一种应用于均匀线列阵的恒定束宽控制方法——空间重采样法,仿真结果表明,在一定的带宽内,系统能够实现恒定束宽,证明了该方法的有效性。此外,仿真实现了空间重采样恒定束控算法在频域宽带波束形成系统中的应用。在频域宽带波束形成时,利用重叠保留法,解决了数据块之间相位不连续的问题。对于系统频带范围外的频点,采用置极小数处理的方法,抑制带外干扰,提高了结果的精确度。

Determination of pKa values of alendronate sodium in aqueous solution by piecewise linear regression based on acid-base potentiometric titration

As a mono-sodium salt form of alendronic acid,alendronate sodium presents multi-level ionization for the dissociation of its four hydroxyl groups.The dissociation constants of alendronate sodium were determined in this work by studying the piecewise linear relationship between volume of titrant and p H value based on acidbase potentiometric titration reaction.The distribution curves of alendronate sodium were drawn according to the determined p Ka values.There were 4 dissociation constants(pKa_1=2.43,pKa_2=7.55,pKa_3=10.80,pKa_4=11.99,respectively) of alendronate sodium,and 12 existing forms,of which 4 could be ignored,existing in different p H environments.

A Linear Interference Cancellation Multi-User Detector for Synchronous CDMA Communications

This paper describes a linear interference cancellation multi user detector for synchronous DS CDMA systems under the condition that all spread spectrum code waveforms have the constant cross correlating coefficients. The basic idea is to get the estimation for total multiple access interference (MAI) of all users using a reference code waveform, then subtract the total MAI from the received signal. The structure of such a detector is nearly similar to the conventional detector. The BER expression obtained in the paper shows significant performance improvement compared to the other detectors.

Fast estimation of Michaelis-Menten constant of arylesterase with a pair of medium concentrations of substrate

Objective: To investigate the reliability for fast estimation of Michaelis-Menten constant (Km) with calibrated specific activity at only two medium concentrations of substrate by both simulation and experimentation with arylesterase (ArE)as model. Methods: Initial rates were simulated by randomly inserting uniform absolute error, and the experimental initial rates of ArE were determined by measuring the increaser of product absorbance. Calibrated specific activities at two substrate concentrations were obtained by regression analysis, and Km was calculated according to Michaelis-Menten equation. Results: By simulation with calibrated specific activities at two medium substrate concentrations, Km could be calculated according to Michaelis-Menten equation with reasonable precision and accuracy. By experimentation with substrates of 2-naphthyl acetate, phenyl acetate, and p-nitrophenyl acetate, there were no differences between the mean and SD of Km of ArE for either substrate by this linear kinetic method and the Lineweaver-Burk plot. Conclusion: This linear kinetic method was reliable for fast estimation of the Km of some specified enzyme on its substrate of lower solubility or lower sensitivity for quantification by common methods.

An Inventory Model for Deteriorating Items with Generalised Exponential Decreasing Demand, Constant Holding Cost and Time-Varying Deterioration Rate

In this present paper, an inventory model with a generalised exponential decreasing demand is considered. A numerical example is used to illustrate the application of the model. Sensitivity analysis of the optimal solution with respect to various parameters is carried out to see the effect of parameter changes on the solution.