A summary of the live-line work on 500 kV transmission lines in China

According to the power system planning in China,500kV transmission line will be the trunks in all regionalnetworks except the Northwest China System.Due to short ofcapital resources,however,most of those 500 kV transmissionlines are and will be operating in single circuit for quite a long pe-riod of time.So,to use the live working techniques on 500 kVlines is an important problem for study.Actually,we had already begun our study on live workingon 500 kV transmission line several years prior to the Ping-Wu     

Electromagnetic field calculation inside a conducting cylinder of finite length using the T-Ω method

Contents The solution of a 3-dimensional problem is, almost in all cases, a quite difficult task, since a great computational effort is required. AT- method accompanied by a boundary element technique is presented for the evaluation of the field inside a conducting cylinder of finite length. The excitation is a current dipole with harmonic time variation (electric Hertzian dipole), located somewhere inside the cylinder. According to the method the problem is split into smaller independent successive problems, requiring much less computational effort.

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Berechnung des elektromagnetischen Feldes innerhalb eines leitenden Zylinders endlicher Länge mit Hilfe der T--Methode

Übersicht Die Lösung des dreidimensionalen Problems ist, fast in allen Fällen, wegen der großen Mühe, die bei den Computerberechnungen erforderlich ist, sehr schwierig. EineT--Methode kombiniert mit einer Randelementtechnik für die Berechnung des Feldes innerhalb eines leitenden Zylinders endlicher Länge wird präsentiert. Ein Hertzscher Dipol an einer beliebigen Stelle innerhalb des Zylinders stellt die Felderregung dar. Entsprechend der Methode wird das Problem in mehrere kleinere, unabhängige sukzessive Probleme, die viel weniger Mühe bei der Computerberechnung erfordern, unterteilt.

     

Quantum kinetics approach to calculation of the low field mobility in the hole inversion layers of silicon MOSFET’s

Analytic expressions for low field mobility have been obtained in the quantized p-type inversion layers. The confining potential is approximated by a triangular quantum well. Main attention is paid to study the dependence of the hole mobility on transverse effective field at different temperatures and concentrations of the ionized impurities. Acoustic and optical phonons, charged impurities, and surface roughness have been adopted as scattering system. Theoretical considerations are based on the quantum kinetic equation and special form of the non-equilibrium distribution function (shifted Fermi distribution). Calculations show that the acoustic phonon limited mobility does not depend on the transverse effective electrical field \(E_\mathrm{eff} \) and has a temperature dependence closer to experiment than known expression for the universal mobility. At the same time, the mobility limited by scattering with optical phonons and surface roughness is proportional to \(E_\mathrm{eff} ^{-1/3}\) and \(E_\mathrm{eff} ^{-2}\), respectively. The mobility limited by scattering by ionized impurities is a weak function of the transverse effective field. Results of the calculations are compared with known experimental data.     

Identification of parameters of models of electric network elements on the basis of Tellegen’s theorem

An evaluation criterion of the permissibility of using the parameters of a model to identify modes of electric network elements with consideration for the constancy of parameters being identified and the error of results based on Tellegen’s theorem is presented. Calculating formulas of proposed criterion for various elements of an electric power system are developed. The proposed criterion makes it possible to detect the presence of distorted information and evaluate the identification error.     

Comment on “Efficient full-path optical calculation of scalar and vector diffraction using the Bluestein method”

The calculation of light diffraction is of great importance for many essential optical applications,including optical lithography,optical tweezers,and super-resolution imaging,and is a research topic that has been extensively studied over the past few decades.Because both scalar and vector diffraction can be formulated as Fourier transforms,the standard method is to use the fast Fourier transform(FFT)algorithm.However,the use of the FFT requires a fixed sampling relation between the discretization of the input field and that of the output field.For the vectorial case,this requirement often causes a significant waste of computational resources,which hinders real-time applications.     

Reply to Comments on “Efficient full-path optical calculation of scalar and vector diffraction using the Bluestein method”

Dear Editor,In ref.we present an efficient full-path optical calculation by using the Bluestein method.A real optical apparatus for laser processing,imaging,or optical tweezing normally involves diverse optical lenses with different physical and numerical apertures(NA).In such applications,the optical path is usually tortuous and long.To assist in the design,evaluation,and alignment of optical instruments,it is advantageous to retrieve the optical field in an arbitrary position along the entire optical path,which is termed the full-path calculation in our paper,with sufficient accuracy and efficiency.In particular,high flexibility is required to accommodate the mismatch between optical apertures of different components in the optical path.We present a fullpath optical calculation method by adopting the Bluestein method to address this realistic demand.