• Journal of the Korean Institute of Landscape Architecture
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• v.43 no.2
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• pp.87-104
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• 2015

As the influence of Landscape Urbanism has grown, various criticisms on the discourse also have increased. A study on critical opinions of Landscape Urbanism is necessary to fully comprehend the theoretical structure of the discourse and its limitations. This study introduced the concept of Intension and Extension, which is used in the field of Logics and Semiotic, as an analytical tool to interpret various criticisms based on different views in a more objective and synthetic way. After examining the development of criticisms of Landscape Urbanism, 30 texts with important critiques on the theory were selected and analyzed. Criticisms can be classified as internal criticism and external criticism according to specific topics they are engaged with. The study only covers internal criticism as a research scope. The internal criticisms on Landscape Urbanism are re-categorized into topics of theory, practice and the relation between theory and practice. Vagueness of concepts and error in concepts are two types criticism related to the issue of theory. Lexical Ambiguity and Intensional Vagueness are the main causes of conceptual vagueness in Landscape Urbanism. Conceptual vagueness related with the problem of redefining an existing concept through expanding its meaning reveals a structural dilemma. There are three types of criticism included in the topic of practice: absence of practical results, form-oriented practice, and ambiguous identity in practical results. Ambiguous identity is caused by Extensional Vagueness allowing borderline cases. Because these borderline cases overlap with extensions of landscape architecture, it is hard to differentiate projects of Landscape Urbanism and those of conventional landscape architecture. Most criticisms on the relation between theory and practice raise the question on the practical method. Two types of criticism are engaged with the topic of the practical method: errors in practical methods and absence of practical methods. The absence of practical methods is a fundamental problem of Landscape Urbanism which is hard to solve by the proposed solutions. However, these structural problems are not only the weak point but also the factor that is able to prove the potentials expand the scope of Landscape Urbanism. In addition to the results of the study, internal criticisms on Landscape Urbanism should be examined in the following studies in order to predict the next direction of Landscape Urbanism.

• The Korean Journal of Nuclear Medicine
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• v.34 no.4
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• pp.336-343
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• 2000

Purpose: Thallous-201 chloride produced at Korea Cancer Center Hospital(KCCH) is used in detecting cardiovascular disease and cancer. Thallium impurity can cause emesis, catharsis and nausea, so the presence of thallium and other metal impurities should be determined. According to USP and KP, their amounts must be less than 2 ppm in thallium and 5 ppm in total. In this study, the detection method of trace amounts of metal impurities in $[^{201}Tl]$TICI injection with polarography was optimized without environmental contamination. Materials and Methods: For the detection of metal impurities, Osteryoung Square Wave Stripping Voltammetry method was used in Bio-Analytical System (BAS) 50W polarograph. The voltammetry was composed of Dropping Mercury Electrode (DME) as a working electrode, Ag/AgCl as a reference electrode and Pt wire as a counter electrode. Square wave stripping method, which makes use of formation and deformation of amalgam, was adopted to determine the metal impurities, and pH 7 phosphate buffer was used as supporting electrolyte. Results: Tl, Cu and Pb in thallous-201 chloride solution were detected by scanning from 300 mV to -800 mV Calibration curves were made by using $TINO_3,\;CuSO_4\;and\;Pb(NO_3){_2}$ as standard solutions. Tl was confirmed at -450 mV peak potential and Cu at -50 mV Less than 2 ppm of Tl and Cu was detected and Pb was not detected in KCCH-produced thallous-201 chloride injection. Conclusion: Detection limit of thallium and copper is approximately 50 ppb with this method. As a result of this experiment, thallium and other metal impurities in thallous-201 chloride injection, produced at Korea Cancer Center Hospital, are in the regulation of USP and KP Polarograph could be applied for the determination of metal impurities in the quality control of radiopharmaceuticals conveniently without environmental contamination.