• International Journal of High-Rise Buildings
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• v.11 no.1
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• pp.15-24
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• 2022

Over the past 30 years, the tall building has seen unprecedented global support. With advanced innovation and many regions around the world discovering increasing growth rates, the tall, supertall, and megatall buildings continue to drastically alter the vertical urbanism of the cities they inhabit. For centuries, urban conditions in most major territories were predominately defined by the street wall and the spaces it shapes. Giambattista Nolli's 1748 Map of Rome most clearly illustrates this significance and possibly solidifies what generations would understand to be the predominant urban condition. As architects, it has been a city's lower vertical wall fabric that has often been the primary focus of efforts to craft an urban experience, and for good reason. Through recent examples of built and unbuilt KPF projects, this paper will explore an upper vertical wall fabric, an urbanism that not only exists at the ground but also within the troposphere.

• Restorative Dentistry and Endodontics
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• v.42 no.2
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• pp.111-117
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• 2017

Objectives: Periapical lesions, including periapical cyst (PC), periapical granuloma (PG), and periapical abscess (PA), are frequently affected by chemical/physical damage during root canal treatment or severe bacterial infection, and thus, the differential diagnosis of periapical lesions may be difficult due to the presence of severe inflammatory reaction. The aim of this study was to make differential diagnosis among PC, PG, and PA under polarizing microscope. Materials and Methods: The collagen birefringence patterns of 319 cases of PC (n = 122), PG (n = 158), and PA (n = 39) obtained using a polarizing microscope were compared. In addition, 6 cases of periodontal fibroma (PF) were used as positive controls. Results: Collagen birefringence was condensed with a thick, linear band-like pattern in PC, but was short and irregularly scattered in PG, and scarce or absent in PA. PF showed intense collagen birefringence with a short, palisading pattern but no continuous band-like pattern. The linear band-like birefringence in PC was ascribed to pre-existing expansile tensile stress of the cyst wall. Conclusions: In this study all PCs (n = 122) were distinguishable from PGs and PAs by their characteristic birefringence, despite the absence of lining epithelium (n = 20). Therefore, the authors suggest that the presence of linear band-like collagen birefringence of the cyst wall aids the diagnostic differentiation of PC from PG and PA.

• Korean Journal of Construction Engineering and Management
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• v.9 no.3
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• pp.118-125
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• 2008

In Korea, five days per week system, duration reduction bidding system, and post sale system have recently stimulated an interest in productivity improvement in construction project. However, analysis result of productivity in Korean construction industry found that the productivity is too low. APC (Architectural PC) is alternative of reveal wall and parapet in apartment housing prcjects and is used abroad broadly because of duration reduction for productivity improving. APC is used as external curtain wall in Dubai, North America, and Southeast Asia. Therefore, it is proposed that necessary to Introduce APC in Korea. The objective of this study is to draw up introduction of APC in apartment housing projects. We analysed the feasibility of the use of APC. The survey results reported that APC would be able to improve the productivity in the eight productivity factors.

• Magazine of the Korea Concrete Institute
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• v.7 no.4
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• pp.119-128
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• 1995

This paper summarizes experimental results for studying feasibility and structural behavior of' a half slab which is getting popularity in recent building construction in favour of the savings in manpower, coats, and construction period. 17 specimens were tested to investigate and analyze the flexural strength of precast concrete slab, half slab, and half slab-wall joint. The primary variables of the testing program were: thickness of precast concrete slab, truss mesh shape, and type of loadings. Test results show that the flexural strength of precast concrete slab in reverse loading is lower than the design strength, but the flexural strength of precast concrete slab, half slab and half slab-wall joint in direct loading is higher than the design srength. No horizontal cracks were found in the connection between insitu concrete and precast concrete slab. The flexural strength of half slab and half slab-wall joint was the same as that of reinforced concrete members. This study concludes that there will not be any structural problem in using a half slab reinforced by truss mesh if props spacing of 2.0m-2.5m, cleanness, and rough finishing between precast concrete and insitu concrete slab are kept.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.9
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• pp.11-18
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• 2018

As the height of the modular buildings increases, their stability becomes more and more dependent on the core. All traditional construction methods in structural concrete and steel can be utilized for cores in modular buildings but a core system with dry connection is more desirable to complete a greater degree of factory finish and faster erection of modular buildings. In order to do that, the hybrid PC(precast concrete) panel, which has a pair of C-shaped steel beams combined at the top and bottom of a concrete wall, was developed, In this study the cyclic lateral loading test on the hybrid PC panel is carried out and the panel configurations are examined to enhance the structural performance in comparison with the RC wall. Experimental results show that the strength of hybrid PC panel is about 70% of thar ot RC wall and the anchorage of vertical reinforcing bar welded to C-shaped steel beam needs to be improved.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.21-24
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• 2005

In this study, new methods of PC panel connection using 'ㄷ'type steel connection is proposed for highly seismic zone. A study was carry out to investigate the connection behavior subjected to cyclic inelastic loading. Three planar type and two T type PC wall will be tested. The variables will be examined were the shear reinforcement existence of top and bottom walls. The specimens will be tested only reverse cyclic loading in accordance with a prescribed displacement history. To transfer the shear strength shear key set up between top and bottom wall. Failure mode, behavior, ductility and energy dissipation capacity of the specimens constructed by new connections wll be compared with those of monolithic walls and Han's(Han, Jun Hee, Seoul National University) model.

• Journal of Information Display
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• v.1 no.1
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• pp.42-47
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• 2000

The relationship between driving voltage and the amount of wall charge in the address period of surface discharge type AC Plasma Display Panel has been investigated. The amount of wall charge on each electrode is obtained simultaneously from the current profiles after applying only one addressing discharge pulse. The wall charge $Q_y$ on the scan electrode Y is almost the sum of $Q_x$ on the address electrode X and $Q_z$ on the sustain electrode Z. The $Q_y$ increased with the driving voltage regardless of the kind of electrode, whereas the addressing $T_d$ decreased. The $Q_x$ and $Q_y$ are increased considerably by blocking voltage $V_z$, whereas $Q_x$ is decreased. The $V_z$ dependence of $Q_x$ $Q_y$ and ${\varrho}_z$ in addressing discharge was $-13{\times}10^{-2}$ (pc/$V_z$), and $60{\times}10^{-2}$ ($pc/V_z$) and $70{\times}10^{-2}(pc/V_z)$, respectively.

• Structural Engineering and Mechanics
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• v.37 no.2
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• pp.177-196
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• 2011

An economic, structurally effective and practically applicable strengthening technique was developed for reinforced concrete (RC) framed buildings. The idea of the technique is to convert the existing hollow brick infill wall into a load carrying system acting as a cast-in-place RC infill wall by bonding relatively thin high strength precast concrete PC panels to the plastered hollow brick infill. For this purpose, a total of eight one-third scale, one bay, one story frames were tested under reversed-cyclic lateral loads. Test frames were designed and constructed with common deficiencies observed in practice. Four different panel types were used for strengthening. Test results showed that both strength and stiffness of the frames were significantly improved by the introduction of PC panels. Experimental results were compared with the analytical approaches suggested by the authors.

• Journal of Korean Society of Steel Construction
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• v.29 no.6
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• pp.435-442
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• 2017

A lateral load resisting system is a necessary structural element for the mid- to high-rise modular buildings and concrete cores are known as the most typical lateral load resisting systems in 10- to 20-story modular buildings. It is difficult to construct a concrete core simultaneously with the installation and finishing work of modular units because concrete placed using wet methods might contaminate or destroy the modular unit. Therefore, we have developed a hybrid PC (precast concrete) panel construction method that can construct a concrete core together with the installation of modular units. The hybrid PC panel is a load-bearing element in which a pair of C-shaped beams are combined at the top and bottom of a concrete wall. Concrete cores can be constructed by dry method to connect the hybrid PC panels with bolts. In this study, the details and connection of hybrid PC panels are improved to have the lateral performance comparable to reinforced concrete structural walls and are verified through FE analysis.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.167-168
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• 2007

$CdIn_2S_4$ (110) films were grown on semi-insulating GaAs (100) by a hot wall epitaxy method. Using photocurrent (PC) measurement, the PC spectra in the temperature range of 30 and 10 K appeared as three peaks in the short wavelength region. It was found that three peaks, A-, B-, and C-excitons, correspond to the intrinsic transition from the valence band states of ${\Gamma}_4(z),\;{\Gamma}_5(x),\;and\;{\Gamma}_5(y)$ to the exciton below the conduction band state of ${\Gamma}_1(s)$, respectively. The 0.122 eV crystal field splitting and the 0.017 eV spin orbit splitting were obtained. Thus, the temperature dependence of the optical band gap obtained from the PC measurement was well described by $E_g$(T)=2.7116eV - $(7.65{\times}10^{-4}\;eV/K)T^2$/(425+T). But, the behavior of the PC was different from that generally observed in other semiconductors. The PC intensities decreased with decreasing temperature. This phenomenon had ever been reported at a PC experiment on the bulk crystals grown by the Bridgman method. From the relation of log $J_{ph}$ vs 1/T, where $J_{ph}$ is the PC density, two dominant levels were observed, one at high temperatures and the other at low temperatures. Consequently, the trapping centers due to native defects in the $CdIn_2S_4$ film were suggested to be the causes of the decrease in the PC signal with decreasing temperature.