• Archives of Pharmacal Research
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• v.23 no.3
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• pp.197-201
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• 2000

In an aqueous piperacillin sodium solution, a well-defined single wave or single peak was observed by direct current(DC) polarography or differential pulse polarography(DPP). The peak potential change per pH unit was -54 mV in the phosphate buffer at $18^{\circ}C$, which indicated that protons were involved in the electrochemical reduction of the 2,3-dioxopiperazine moiety of piperacillin sodium with a $H^{+}e^{-}$ ratio of one. Using a phosphate buffer of pH 4.3, the $1.0{times}10^{-7}$ M piperacillin sodium single peak could be determined by DPP with relative standard deviation of 1.6 %(n=3). Piperacillin sodium could be analyzed with-out interference from penicillin G-potassium, which enabled the employment of DPP as a fast and simple technique for monitoring the synthetic process of the antibiotic.

• Journal of The Korean Astronomical Society
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• v.29 no.spc1
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• pp.219-221
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• 1996

The x-ray pulsar GX 1+4 was observed by us in four balloon- borne experiments carried out from Hyderabad, India during 1991-1995 period with a hard x-ray telescope. The x-ray telescope consists of two collimated large area xenon-filled proportional counters with an effective area of $2400 cm^2$, a field of view of $5^{\circ}{\times}5^{\circ}$ and sensitive in the energy band of 20 - 100 keV. The pulsar was detected in bright state in two of the four experiments and x-ray pulsations with 120 second period were detected clearly. Pulsation period, rate of change of period with time, pulse fraction, pulse profile and energy spectra of the source were determined from these studies. During March 1995 observation, the x-ray pulse of GX 1+4 was found to be double-peaked compared to a single-peak pulse profile detected in December 1993. Details of these results are presented and their interpretation discussed in terms of the current accretion models of x-ray binaries.

• Journal of Power Electronics
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• v.1 no.2
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• pp.65-70
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• 2001

Transmission System Operators are governed by operational security standards that are applied in real time. During system disturbances, the System Operators must rely on the installed protection and control equipment, prior to human intervention. New power electronic solutions bring rapid and repeatable responses to disturbances, which will help System Operators to guarantee a stable system. Last year, Alstom completed the world's first competitively bid STATCOM to support the voltage on National Grid's 400kV network that supplies London and the Southeast from the north of the UK. It is rated ${\pm}75MVAr$ and forms part of a Static Var System (SVS) with a total rating of 0 to 225MVAr. This paper will describe the reasons for its size, location, its chain-link configuration and give examples of its operating performance. The paper will also describe the features that allow this STATCOM to deliver much more than reactive compensation in support of a wider transmission service objective, as system conditions require.

• Progress in Superconductivity
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• v.3 no.1
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• pp.83-86
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• 2001

We have fabricated a single flux quantum 4-stage shift register with interface-controlled $Y_1$$Ba_2$$Cu_3$$O_{7-x}$(YBCO) Josephson junction. The YBCO Josephson junctions showed RSJ-like current-voltage(I-V) curves at temperatures 45~80K. We tested load and shift operation of shift register with binary data sequences “1000”, “1010”, “1011”, and “1111” at 58K. For all the binary data sequences, the shift register operated successfully. By operating the circuit with proper current pulses, we observed no errors during at least 12 hours operation for all the data sequences.s.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.34-34
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• 2003

Piezoelectric or magnetostrictive materials, known as smart materials, have been researched widely for sensors or actuators in micro system technology. In our research, thick sol-gel lead zirconate titanate(Pb(Zr$\sub$1-x/Ti$\sub$x/)O$_3$) films were fabricated and their characteristics were investigated f3r angular rate sensor applications. The thickness of the PZT films is 1.5${\mu}$m, which is required by a vibration angular rate sensor for a good actuation and sensing. The remnant polarization of the PZT flms is 12.0 ${\mu}$C/$\textrm{cm}^2$. The electromechanical constants of PZT thin film showed the value of susceptance(B) of 4800${\mu}$ s at capacitance of 790pF. The PZT films were applied to the vibration angular rate sensor structure and the vibration of 1.78 ${\mu}$m in amplitude at the resonant frequency of 35.8㎑ was obtained by driving voltage of 5V$\sub$p-p/ of bulk piezoelectric materials with out of phase signal through voltage and inverting amplifier.

• Nonlinear Functional Analysis and Applications
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• v.28 no.2
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• pp.473-495
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• 2023

The use of mathematical modelling in the study of epidemiological disorders continues to grow substantially. In order to better support global policy initiatives and explain the possible consequence of an outbreak, mathematical models were constructed to forecast how epidemic illnesses spread. In this paper, fractional derivatives and (${\varpi}$ - F_𝓒)-contractions are used to explore the existence and uniqueness solutions of the novel coronavirus-19 model.

• Journal of the Korean Vacuum Society
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• v.7 no.s1
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• pp.78-84
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• 1998

Niobium ions of 380 keV energy have been implanted at 300k in sapphire with a dose of $5\times10^{16}\textrm{ions/cm}^2$ and subsequently thermal annealed up to $1100^{\circ}C$ at reducing atmosphere. The behavior of the radiation damage produced by ion implantation followed by annealing is investigated using optical absorption technique and X-ray photoelectron spectroscopy(XPS). It is found that different defects annealed are dependent on the annealing temperature owing to different mechanisms which are proposed on the basis of the optical absorption measurement, and the implanted niobium in sapphire is in different local environments with different charge states after annealing, which are analyzed by XPS measurements.

• Journal of the Korean Institute of Telematics and Electronics
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• v.24 no.2
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• pp.230-237
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• 1987

This paper proposes a compatible variables scheduling algorithm, which is the process to pack variables into same register without modifying program semantics, for efficient register allocation of microprogram. The algorithm constructs T-V matrix, obtains incompatible variable set and scheduling priority, and schedules compatible groups. By this algorithm, the number of compatible groups can be minimized. The algorithm was implemented with C language on VAX-11/780 computer. By applying the algorithm to practical microprograms, the effectiveness of the algorithm is verified.

• Journal of applied mathematics & informatics
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• v.42 no.2
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• pp.433-444
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• 2024

Our study explores the connection between the Pythagorean theorem and the Fixed-point theorem in metric spaces. Both of which center around the concepts of distance transformations and point relationships. The Pythagorean theorem deals with right triangles in Euclidean space, emphasizing distances between points. In contrast, fixed-point theorems pertain to the points that remain unchanged under specific transformations thereby preserving distances. The article delves into the intrinsic correlation between these concepts and presents a novel study in Euclidean metric spaces, examining the relationship between contraction mapping and Pythagorean Right Triangles. Practical applications are also discussed particularly in the context of image compression. Here, the integration of the Pythagorean right triangle paradigm with contraction mappings results in efficient data representation and the preservation of visual data relation-ships. This illustrates the practical utility of seemingly abstract theories in addressing real-world challenges.

• Nonlinear Functional Analysis and Applications
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• v.29 no.2
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• pp.461-475
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• 2024

The concept of an extension α-F-contraction and it's modified counterpart represents an advancement in the theory of metric space contractions. Through our study of the contraction principles and it's relationship to extension and modified extension, we found different conditions somewhat lengthy. In our paper, we create a development of the conditions for the extension of α-F-contraction and a modified α-F-contraction by reducing the conditions and make them easier. Our propose conditions are notably simple and effective. They serve as the foundation for proving theorems and solving examples that belong to our study. Moreover, they have remarkable significance in the condition of mathematical analysis and problem-solving. Thus, we find that these new conditions that we mention in the definitions achieve what is require and through them, we choose λ = 1 and we choose λ ∈ (0, 1) to clarify our ideas.