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1

Modelling dynamics of transmission conductors with Cosserat rod

Xiong H., Li Z. L., Chang J., You L., Zhang J. J., Wang M.

Computer Assisted Methods in Engineering and Science

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2013

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Vol. 20, no. 1

73--79

EN

We proposed a method to analyze the galloping, a vibration by wind force, of transmission conductors. The Cosserat rod model was introduced to describe the motion of the conductor line. The deformation was tracked using the intrinsic framework of material coordinates which are able to handle the large motion in galloping phenomena. The Cosserat model provided a theory framework to simulate the non-linear coupling of the torsional motion and the translational motion. Such non-linear coupling was reported as one of the main causes for the galloping phenomena.

2

Research and Implementation of CATIA Tool Integration Technology Based on CAA

Kong X., Qiu Y., Chang J.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 7b

300--302

EN

In order to implement the integration of the tool libraries from CATIA and the tool database, CATIA software was further developed using CAA. CAA macro-based integration project about the two libraries is proposed, and the development process is presented. In CAA environment provided by CATIA, though further developed using CAA, calling for information, converting information and valuating information of CATIA and TOOLMANAGER were researched. Finally, the dynamic calling, association and driving of CATIA-based tool information were implemented successfully.

PL

W artykule analizuje się możliwości oprogramowania CATIA służącego do projektowania typu CAD/CAE/CAM. W analizie wykorzystano architekturę typu CAA (component application architecture).

3

Determination of interfacial parameters of horizontal two-phase plug flow using a high speed pulse-echo ultrasonic technique

Masala T., Harvel G., Su J., Chang J.

Transactions of the Institute of Fluid-Flow Machinery

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2010

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nr 122

61-76

EN

This paper presents a high-speed, multiple-transducers, pulse-echo ultrasonic technique for the measurement of interfacial parameters of horizontal two-phase intermittent flow regimes. The ultrasonic system consisted of an ultrasonic driver, a multiplexer with 4 transducers, and a microcomputer equipped with a data acquisition card, a motion controller card and the Winspect Data Acquisition software. Two transducers were mounted on the top of a 2.1 cm inner diameter circular pipe, while the other two transducers were mounted on the bottom of the pipe. Using instantaneous liquid level measurements from multiple transducers, two-phase flow interfacial parameters in plug were determined, such as the lengths and the velocities of liquid plugs and bubbles, the shape of the gas-liquid interface, and hence instantaneous and cross sectional averaged void fraction and interfacial area. The results showed that the liquid plug velocities as well as the elongated bubble velocity increases with increasing superficial liquid and gas velocities. An experimental correlation for liquid plug velocity was proposed based on the present results. The results also showed that the time and cross-sectional averaged void fraction in the plug flow regime was only slightly influenced by the superficial gas velocity but was not influenced by the superficial liquid velocity.

4

Columbia Application Performance Tuning Case Studies

Chang J.

Computational Methods in Science and Technology

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2006

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Vol. spec. issue

13-21

EN

This paper describes four case studies of application performance enhancements on the Columbia supercomputer. The Columbia supercomputer is a cluster of twenty SGI Altix systems, each with 512 Itanium 2 processors and 1 terabyte of global sharedmemory, and is located at the NASA Advanced Supercomputing (NAS) facility in Moffett Field. The code optimization techniques described in the case studies include both implicit and explicit process-placement to pin processes on CPUs closest to the processes’ memory, removing memory contention in OpenMP applications, eliminating unaligned memory accesses, and system profiling. These techniques enabled approximately 2- to 20-fold improvements in application performance.

5

A scalability Study of Columbia using the NAS Parallel Benchmarks

Saini S., Chang J., Hood R., Jin H.

Computational Methods in Science and Technology

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2006

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Vol. spec. issue

33-45

EN

The Columbia system at the NASA Advanced Supercomputing (NAS) facility is a cluster of 20 SGI Altix nodes, each with 512 Itanium 2 processors and 1 terabyte (TB) of shared-access memory. Four of the nodes are organized as a 2048-processor capabilitycomputing platform connected by two low-latency interconnects – NUMALink4 (NL4) and InfiniBand (IB). To evaluate the scalability of Columbia with respect to both increased processor counts and increased problem sizes, we used seven of the NAS Parallel Benchmarks and all three of the NAS multi-zone benchmarks. For NPB we ran three Classes B, C, and D of benchmarks. To measure the impact of some architectural features, we compared Columbia results with results obtained on a Cray Opteron Cluster consisting of 64 nodes, each with 2 AMD Opteron processors and 2 gigabytes (GB) of memory, connected with Myrinet 2000. In these experiments, we measured performance degradation due to contention for the memory buses on the SGI Altix BX2 nodes. We also observed the effectiveness of SGI’s NL4 interconnect over Myrinet. Finally, we saw that computations spanning multiple BX2 nodes connected with NL4 performed well. Some computations did almost as well when the IB interconnects was used.

6

Treatment of odour gas from air stream by a multi-channel corona torch - adsorbent filter hybrid system

Urashima K., Chang J., Karibe F., Hashimoto M., Urashima K., Chang J., Karibe F., Hashimoto M.

Transactions of the Institute of Fluid-Flow Machinery

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2000

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Nr 107

101-110

EN

The odour gases such as ammonia, H2S, VOCs etc. generate significant problems during product processing and it will be influencing to the semiconductor device manufacturing yields in a clean room operation. In this work, the experimental study on the removal of a trace ammonia gas from air stream was carriedout by a corona torch - adsorbend hybrid system. The corona torch - adsorbent hybrid system consist of a multi-channel hollow electrode type corona torch, and sheet type adsorbend (Pureline* by Nippon Puretec Co., Ltd.,), where this adsorbend can be operated under room to elevated temperatures. Experiments were conducted for the gas flow rate from 0.42 to 0.84 Nm3/h., the applied voltage from 22 to 34 kV and the ammonia initial concentration from 60 to 120 ppm. An ammonia concentration was measured by the ammonia monitoring system (Pure Mate*, by Nippon Puretec Co.,) and the gas detector (Gastec*, by Gastec Co., Ltd.,). The results show that the remowal efficiency of ammonia increases with increasing applied power and up to 120 g of ammonia can be removed by 1 kWh of electric power inputs.

PL

Usuwanie gazów wonnych z powietrz za pomocą kombinowanego układu filtra adsorbującego z reaktorami wyładowania typu "corona torch". Gazy wonne takie jak amoniak, siarkowodór czy lotne związki organiczne stwarzają szereg problemów przy produkcji półprzewodników. Praca dotyczy usuwania amoniaku ze strumienia powietrza za pomocą systemu składającego się z kilku reaktorów wyładowania elektrycznego typu "corona torch" i adsorbera (Piruline*, firmy Nippon Puretec). Natężenie przepływu powietrza podczas badań eksperymentalnych wynosiło 0,42-0,84 m3/h, napięcie zasilania 22-34 kV, a stężenie początkowe amoniaku w powietrzu 60-120 ppm. Stężenie amoniaku mierzono za pomocą układu monitoryjącego Pure Mate* , firmy Nippon Puretec, i detektora gazów firmy Gastec. Wyniki badań wskazują na możliwość usuwania za pomocą opracowanego systemu do 120 g amoniaku na 1 kWh doprowadzonej mocy.

7

Electrophoretic behaviour and quantitative analysis of active components 6,7-dehydroroyleanone and taxoquinone extracted from Salvia deserta Schang

Zhao Y., Cao Q., Chen X., Hu Z., Fu B., Chang J.

Chemia Analityczna

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2000

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Vol. 45, No. 2

237-248

EN

This communication demonstrates that micellar electrokinetic chromatography (MEKC) can be convenient for the determination of minor active components 6,7-dehydro-royleanone and taxoquinone in the extract of the traditional Chinese medicinal herb. 6,7-Dehydroroyleanone and taxoquinone can be monitored selectively and sensitively at 254 nm within 8 min in the plant extract, using alfa-cyclodextrin (alfa-CD) as a MEKC modified. The concentration range was 5-500 ug ml-1 for 6,7-dehydroroyleanone and 2.5-750 ug ml-1 for taxoquinone with good linear correlation coefficients 0.9997 and 0.9989, respectively. It was found that 68.2 ug of 6,7-dehydroroyleanone and 12.5 ug of taxoquinone were contained in 1 g of Salvia deserta Schang roots. The inclusion of 6,7-dehydroroyleanone and taxoquinone with alfa-CD in capillary zone electrophoresis (CZE) was studied, and the inclusion constant logKCD were 4.1 and 3.2 for 6,7-dehydroroyleanone and taxoquinone, respectively.

PL

Wykazano, że metoda elektrokinetycznej chromatografii micelarnej (MEKC) może być zastosowana do oznaczania 6,7-dehydrorojleanonu i taksochinonu w ekstraktach surowców roślinnych. Oba biologicznie aktywne związki są ubocznymi składnikami ziół stosowanych w chińskiej medycynie tradycyjnej. Zastosowanie p-cyklodekstryn jako moodyfikatora, pozwala na selektywne oznaczenie obu związków ze znaczną czułością w ciągu 8 min przy 254 nm. Dla 6,7-dehydrorojleanonu i taksochinonu, w zakresie stężeń 5-500 ug ml-1 i 2.5-750 ug ml-1, otrzymano współczynniki korelacji odpowiednio -0.9997 i 0.9989. Stwierdzono, że l g korzeni Sahia deserta Schang zawiera 68.2 ug 6,7-dehydrorojleanonu i 12.5 ug taksochinonu. Za pomocą kapilarnej elektroforezy strefowej zbadano inkluzje obu związków z alfa-cyklodekstryną. Wyznaczono stałe inkluzji logKcD 4.1 i 3.2 odpowiednio dla 6,7-dehydrorojleanonu i taksochinonu.

8

Numerical simulations for HgCdTe related detectors

Yoo S. D., Jo N. H., Ko B. G., Chang J., Park J. G., Kwack K. D.

Opto-Electronics Review

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1999

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Vol. 7, No. 4

347-356

EN

In this paper we introduce a new HgCdTe 2-dimensional numerical simulator, HanYang University Semiconductor Device Simulator (HYSEDES). HYSEDES adopts the modifield transport models to describe the inherent natures of HgCdTe such as the degeneracy, the nonparabolic conduction band, and the band offset at heterointerface. It also takes into account various generation - recombination mechanisms regarding tunnelling phenomena and optical generation. For the advanced devices employing multiple junctions, all the material parameters are described as a function of the position. The simulation results are reported for photovoltaic devices and focal plane array. We also proposed a structure to improve the characteristics in focal plane array, i. e., to reduce crosstalk with slight degrading quantum efficiency.