Linear Transfer Systems Research Articles

Measurement of AC Loss Characteristics of HTS Sample Coils Under the Conditions Assumed for use in Power Electronics Devices

To examine the applicability of superconducting technology to fields of industrial applications such as linear conveyor, transfer, and transport systems, we investigated the AC loss characteristics of HTS sample coils under conditions assumed for use in power electronics devices. Since inverters are used in the drive circuit of power electronics devices in a linear transfer system and so on, the drive current contains harmonic components, and then it is expected that the AC losses increase. In this study, we measured the AC loss characteristics of the HTS sample coil by the liquid nitrogen boil-off method under various conditions in which the amplitude and frequency of the harmonic current were changed. The HTS sample coils were wound by a Bi-2223 tape. The outer diameter of the sample coil is about 60 mm, and the height is about 25 mm. As the result of the measurement, the AC loss increased in proportion to the square of the harmonic current amplitude and increased in proportion to the 1.5th power of the harmonic frequency. Based on the measured results, the increase of AC losses due to the harmonic current component was discussed.

Size-exclusion chromatography as a linear transfer system: Purification of human influenza virus as an example

Preparative size-exclusion chromatography suffers from low selectivity and productivity. Empirical optimization of operating conditions constitutes a laborious task due to many parameters. Here, a modeling framework based on linear systems theory is presented for predicting the influence of volume overloading. Impulse-responses characterizing system behavior are derived from experimental data by maximum entropy deconvolution. Theoretical derivations are validated experimentally by study of a model system and chromatography of human influenza virus. By application of the theory it is demonstrated how group separation operations can be optimized with respect to yield, purity, productivity and dilution of the product.

비접촉 전원장치에 적용한 LCC형 고주파 공진 DC/DC 컨버터에 관한 연구

본 논문은 부하직렬 고주파 공진 DC/DC 컨버터에 가변 가능한 공진커패시터를 병렬로 삽입한 LCC형 고주파 공진 DC/DC 컨버터의 특성과 설계 예를 나타내고 있으며, 또한 턴-오프시 스위칭 손실을 줄이기 위해 ZVS를 가지는 소프트 스위칭을 사용하였다. 제안 컨버터는 PFM(Pulse Frequency Modulation 스위칭 패턴을 사용하여 동작되며, PFM 제어에 의해 제안 회로의 출력전압을 제어하였다. 병렬커패시터의 커패시턴스의 변화에 따라, DC/DC 컨버터의 분석은 일반적으로 무차원화 파라미터를 사용하여 나타내었고, 회로 동작 특성은 스위칭 주파수와 파라미터로 행하였다. 또한 본 논문은 특성평가에 의해 제안 DC/DC 컨버터의 동작 특성과 회로 설계 방법을 제시하였다. 더욱이 본 논문은 실험을 통해 이론 분석의 정당성을 입증하였다. 향후 제안한 DC/DC 컨버터는 반도체 및 FPD의 클린룸에 선형이동 시스템의 비접촉 전원장치에 적용 가능하다고 생각된다.

Multistep linear transfer system

Multistep linear transfer system

Identifikation von Interferenzschichtsystemen

A unified approach to methods and tendencies in the identification of layered media within the framework of systems theory is given. New results concerning the holomorphic properties of transfer coefficients and their characterization by differential equations come to bear. A complete universal method for the synthesis of optimal achromatic systems has been developed. - With regard to the reflection or transmission of electromagnetic waves stratified media act as linear transfer systems. The guiding principle in their identification has been to operate in the following two steps: the first objective in mind is to determine the system function depending on the frequency; based upon this characteristic of the system one then explores its internal structure. These conceptions have been carried out for a homogeneous halfspace and a stack of homogeneous layers of equal optical thickness. The methods are discussed with regard to the significance of measurements as well as prescribed values.

System identification and approximation in the time domain with ramp-shaped output signals

A method of modelling linear transfer systems of higher order based on ramp-shaped output signals is described. The characteristic values necessary are derived from the experiment, defined by mathematical equations and made available to evaluation as a characteristic value diagram. The method works in the time domain and is suited to system identification from measured data as well as to approximation of dynamic relations difficult to represent.