• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.13 no.3
• /
• pp.220-226
• /
• 2000

The piezoelectric material for piezoelectric transformer needs the high electromechanical coupling factor( $k_{p}$) the piezoelectric constant( $d_{33}$) and the mechanical quality factor( $Q_{m}$)in order to obtain high voltage step-up ratio and low temperature rising. In this study the piezoelectric transformers were fabricated using Pb［$Zr_{0.45}$/ $Ti_{0}$48//L $u_{0.02}$(M $n_{1}$3//S $b_{2}$3/)$_{0.05}$］ $O_3$(PMS-PZT) and Pb［Z $r_{0.25}$/ $Ti_{0.375}$(M $g_{1}$3//N $b_{2}$3/)$_{0.375}$］ $O_3$+0.5wt%Mn $O_2$(PMN-PZT) ceramics. The piezoelectric properties of PMS-PZT and PMN-PZT were measured. The voltage set-up ratios of the piezoelectric transformers using PMS-PZT and PMN-PZT were the value of 15, 20 respectively under 100$_{KΩ}$ in Rosen type transformer.r.ormer.r.r.r.r.r.r.

• Korean Journal of Soil Science and Fertilizer
• /
• v.45 no.1
• /
• pp.112-117
• /
• 2012

The Revised Universal Soil Loss Equation (RUSLE) is a revision of the Universal Soil Loss Equation (USLE). However, changes for each factor of the USLE have been made in RUSLE which can be used to compute soil loss on areas only where significant overland flow occurs. RUSLE which requires standardized methods to satisfy new data requirements estimates soil movement at a particular site by utilizing the same factorial approach employed by the USLE. The rainfall erosivity in the RUSLE expressed through the R-factor to quantify the effect of raindrop impact and to reflect the amount and rate of runoff likely is associated with the rain. Calculating the R-factor value in the RUSLE equation to predict the related soil loss may be possible to analyse the variability of rainfall erosivity with long time-series of concerned rainfall data. However, daily time step models cannot return proper estimates when run on other specific rainfall patters such as storm and daily cumulative precipitation. Therefore, it is desirable that cross-checking is carried out amongst different time-aggregations typical rainfall event may cause error in estimating the potential soil loss in definite conditions.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.26 no.11
• /
• pp.966-977
• /
• 2015

This paper presents a novel modified coaxial cavity resonator and its application to bandpass filters with compact size and improved quality factor(Q-factor). The proposed resonator is made up of ${\Gamma}-shape$ or curved four inner conductive posts within a single cavity, which provides quadruplet to realize bandpass filter. No metallic walls inside the cavity are required, and thus the utilization efficiency of the cavity space is improved. As a result, the unloaded Q can be approximately 15 % higher in comparison to the conventional coaxial resonator, or more than 35 % volume saving can be achieved while maintaining the similar Q-factor value with the conventional designs. In addition, due to the multiple cross-coupling occurring within the cavity, including the source-to-load coupling, four flexible transmission zeros can be created to realize different filtering functions. Simulations as well as experimental results of four- and eight-pole filters are presented to validate this attractive design concept. Good agreement between measured and computed results is obtained.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.7 no.4
• /
• pp.681-693
• /
• 1995

A new set of capillary tube selection charts for R-22 is proposed. The set of charts takes into account of the roughness effect on the mass flow rate. For this purpose, a set of numerical model is developed and a series of experiments is conducted to verify the numerical model. A numerical model is used to calculated the mass flow rate for several sets of tube diameter, length, inlet pressures and degree of subcooling. The outlet of the tube is controlled to be at critical condition. The experimental flow rate is compared with calculated values. The calculated values are consistently less than the experimental ones except for the flow rate range below 40kg/hr. The deviation is within 10---. Based on the nunmerical model and results of experiments, the set of capillary tube selection charts for R-22 is constructed. The set of charts consists of standard capillary tube chart(L=2030mm, d=1.63mm, ${\varepsilon}=2.5{\mu}m$), non -standard flow factor(${\phi}_1$) chart, and non-standard roughness factor(${\phi}_2$) chart. The mass flow rate, flow factor, and the roughness factor are defined respectively as; $\dot{m}={\phi}_1{\phi}_2\dot{m}_{standard}\\{\phi}_1=\frac{\dot{m}(L,\;d,\;\varepsilon_{standard})}{\dot{m}_{standard}(L_{standard},\;d_{standard},\;{\varepsilon}_{standard})}\\{\phi}_2=\frac{\dot{m}(L_{standard},\;d_{standard},\;{\varepsilon})}{\dot{m}_{standard}(L_{standard},\;d_{standard},\;{\varepsilon}_{standard})}$.

• KSBB Journal
• /
• v.24 no.3
• /
• pp.259-266
• /
• 2009

AfsR2 in Streptomyces lividans, a 63-amino acid protein with limited sequence homology to Streptomyces sigma factors, has been known for a global regulatory protein stimulating multiple antibiotic biosynthetic pathways. Although the detailed regulatory mechanism of AfsK-AfsR-AfsR2 system has been well characterized, very little information about the AfsR2-dependent down-stream regulatory genes were characterized. Recently, the null mutant of afsS in S. coelicolor (the identical ortholog of afsR2) has been characterized through DNA microarray system, revealing that afsS deletion regulated several genes involved in antibiotic biosynthesis as well as phosphate-starvation. Through comparative DNA microarray analysis of afsR2-overexpressed S. lividans, here we also identify several afsR2-dependent genes involved in phosphate starvation, morphological differentiation, and antibiotic regulation in S. lividans, confirming that the AfsR2 plays an important pleiotrophic regulatory role in Streptomyces species.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.11 no.1
• /
• pp.171-182
• /
• 2015

The general wavelet transform has profitable property in non-stationary signal analysis specially. The tunable Q-factor wavelet transform is a fully-discrete wavelet transform for which the Q-factor Q and the asymptotic redundancy r, of the transform are easily and independently specified. In particular, the specified parameters Q and r can be real-valued. Therefore, by tuning Q, the oscillatory behavior of the wavelet can be chosen to match the oscillatory behavior of the signal of interest, so as to enhance the sparsity of a sparse signal representation. The TQWT is well suited to fast algorithms for sparsity-based inverse problems because it is a Parseval frame, easily invertible, and can be efficiently implemented. The transform is based on a real valued scaling factor and is implemented using a perfect reconstruction over-sampled filter bank with real-valued sampling factors. The transform is parameterized by its Q-factor and its over-sampling rate, with modest over-sampling rates being sufficient for the analysis/synthesis functions to be well localized. This paper describes filter design of 2D discrete-time wavelet transform for which the Q-factor is easily specified. With the advantage of this transform, perfect reconstruction filter design and implementation for performance improvement are focused in this paper. Hence, the 2D transform can be tuned according to the oscillatory behavior of the image signal to which it is applied. Therefore, application for performance improvement in multimedia communication field was evaluated.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.10 no.3
• /
• pp.237-247
• /
• 2014

This paper describes a 2D discrete-time wavelet transform for which the Q-factor is easily specified. Hence, the transform can be tuned according to the oscillatory behavior of the image signal to which it is applied. The tunable Q-factor wavelet transform (TQWT) is a fully-discrete wavelet transform for which the Q-factor, Q, of the underlying wavelet and the asymptotic redundancy (over-sampling rate), r, of the transform are easily and independently specified. In particular, the specified parameters Q and r can be real-valued. Therefore, by tuning Q, the oscillatory behavior of the wavelet can be chosen to match the oscillatory behavior of the signal of interest, so as to enhance the sparsity of a sparse signal representation. The TQWT is well suited to fast algorithms for sparsity-based inverse problems because it is a Parseval frame, easily invertible, and can be efficiently implemented. The TQWT can also be used as an easily-invertible discrete approximation of the continuous wavelet transform. The transform is based on a real valued scaling factor (dilation-factor) and is implemented using a perfect reconstruction over-sampled filter bank with real-valued sampling factors. The transform is parameterized by its Q-factor and its oversampling rate (redundancy), with modest oversampling rates (e. g. 3-4 times overcomplete) being sufficient for the analysis/synthesis functions to be well localized. Therefore, This method services good performance in image processing fields.

• Earthquakes and Structures
• /
• v.14 no.6
• /
• pp.537-549
• /
• 2018

Using vertical links in eccentric braced frames is one of the best passive structural control approaches due to its effectiveness and practicality advantages. However, in spite of the subject importance there are limited studies which evaluate the seismic reliability and response reduction factor (R-factor) in this system. Therefore, the present study has been conducted to improve the current understanding about failure mechanism in the structural systems equipped with vertical links. For this purpose, following definition of demand and capacity response reduction factors, these parameters are computed for three different buildings (4, 8 and 12 stories) equipped with this system. In this regards, pushover and incremental dynamic analysis have been employed, and seismic reliability as well as multi-level response reduction factor according to the seismic demand and capacity of the frames have been derived. Based on the results, this system demonstrates high ductility and seismic energy dissipation capacity, and using the response reduction factor as high as 8 also provides acceptable reliability for the frame in the moderate and high earthquake intensities. This system can be used in original buildings as lateral load resisting system in addition to seismic rehabilitation of the existing buildings.

• Structural Engineering and Mechanics
• /
• v.82 no.1
• /
• pp.55-67
• /
• 2022

The precast reinforced concrete frame system is a method for industrialization of construction. However, the seismic performance factor of this structural system is not explicitly clarified in some existing building codes. In this paper, the seismic performance factor for the existing precast concrete building frame systems with cast-in-situ reinforced shear walls were evaluated. Nonlinear behavior of the precast beam-column joints and cast-in-situ reinforced shear walls were considered in the modeling of the structures. The ATC-19's coefficient method was used for calculating the seismic performance factor and the FEMA P-695's approach was adopted for evaluating the accuracy of the computed seismic performance factor. The results showed that the over-strength factor varies from 2 to 2.63 and the seismic performance factor (R factor) varies from 5.1 to 8.95 concerning the height of the structure. Also, it was proved that all of the examined buildings have adequate safety against the collapse at the MCE level of earthquake, so the validity of R factors was confirmed. The obtained incremental dynamic analysis (IDA) results indicated that the minimum adjusted collapse margin ratio (ACMR) of the precast buildings representing the seismic vulnerability of the structures approximately equaled to 2.7, and pass the requirements of FEMA P-695.

• Korean Journal of Soil Science and Fertilizer
• /
• v.16 no.2
• /
• pp.106-111
• /
• 1983

As calculation of R factor value in the Universal Soil-Loss Equation is tedious, a new simple method (IAS Index) to approximate the R factor value is proposed. Although the several methods have been tested to get R value, no one fits our conditions. IAS Index is simply calculated by summing up the amount of rainfall over two months with maximum $EI_{30}$ values. The Index is highly correlated to $EI_{30}$ value in western part of peninsular. The difference is less than 10% between $EI_{30}$ value and IAS Index. Therefore, R factor can be estimated from IAS index, summing up the rainfall amount of June and August in this region. However, IAS Index works poorly in other region, especially, eastern coastal side. The large difference may be partly due to side distribution of $EI_{30}$ value, which means no special $EI_{30}$ peaks during heavy rainy months. In this case, IAS Index is not applicable directly.