• Advances in Energy Research
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• 제4권1호
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• pp.87-106
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• 2016

In this research, optimum design of the combined solar collector, geothermal heat pump and thermal seasonal storage system for heating and cooling a sample greenhouse is studied. In order to optimize the system from technical point of view some new control strategies and functions resulting from important TRNSYS output diagrams are presented. Temperatures of ground, rock bed storage, outlet ground heat exchanger fluid and entering fluid to the evaporator specify our strategies. Optimal heat storage is done with maximum efficiency and minimum loss. Mean seasonal heating and cooling COPs of 4.92 and 7.14 are achieved in series mode as there is no need to start the heat pump sometimes. Furthermore, optimal parallel operation of the storage and the heat pump is studied by applying the same control strategies. Although the aforementioned system has higher mean seasonal heating and cooling COPs (4.96 and 7.18 respectively) and lower initial cost, it requires higher amounts of auxiliary energy either. Soil temperature around ground heat exchanger will also increase up to $1.5^{\circ}C$ after 2 years of operation as a result of seasonal storage. At the end, the optimum combined system is chosen by trade-off between technical and economic issues.

• Journal of international Conference on Electrical Machines and Systems
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• 제3권3호
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• pp.339-353
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• 2014

A straightforward method for optimal determining of a high frequency inductor's parasitic capacitance is presented. The proposed estimation method is based on measuring the inductor's impedance samples over a limited frequency range bordering on the resonance point considering k-dB deviation from the maximum impedance. An optimized solution to k could be obtained by minimizing the root mean squared error between the measured and the estimated impedance values. The model used to provide the estimations is a parallel RLC circuit valid at resonance frequency which will be transferred to the real model considering the mentioned interval of frequencies. A straightforward algorithm is suggested and programmed using MATLAB which does not require a wide knowledge of design parameters and could be implemented using a spectrum analyzer. The inputs are the measured impedance samples as a function of frequency along with the diameter of the conductors. The suggested algorithm practically provides the estimated parameters of a real inductance model at different frequencies, with or without design information. The suggested work is different from designing a high frequency inductor; it is rather concentration of determining the parameters of an available real inductor that could be easily done by a recipe provided to a technician.

• Archives of Reconstructive Microsurgery
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• 제11권2호
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• pp.135-140
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• 2002

It has been known that latissimus dorsi(LD) myocutaneous flap based on thoracodorsal artery is one of most useful method for microreconstructive surgery and the thoracodorsal artery of this flap has constant vascular anatomy. The retrospective study for anatomy of the thoracodorsal arterial system was performed at operative cases. The aim of this study was to document the anatomical variation of this pedicle clinically. 167 LD flaps were carried out from 1983 to 2002 in our clinic. We found unusual 7(4.2%) cases compared to standard textbooks of anatomy. One case was no vascular supply to LD muscle. In 2(1.2%) cases thoracodorsal artery was a typical branch of the subscapular artery but didn't branch to LD muscle, passed to lower serratus anterior muscle, and at this point, supplied vessel to LD muscle and it's vascular diameter was about 1mm diameter. The thoracodorsal artery arose from the axillary artery in 1.8% of cases(3 cases). One case had less than 1mm vascular diameter but a branch of subscapluar artery. It should be emphasized that we must elevate the latissimus dorsi flap after accurate cognition for the anatomy of thoracodorsal artery because the thoracodorsal arterial system is almost reliable but not uniform in rare cases.

• Archives of Reconstructive Microsurgery
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• 제13권1호
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• pp.29-35
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• 2004

Materials and Methods: Total number of peroneal perforator flap is 14 cases, which 10 cases were man, 4 cases were woman. The range of age was 12 years old minimally and until 63 years old. The trauma was most common etiology, which was like traffic accidents, 9 cases. We confirmed tibialis anterior artery patency by doppler flow meter, angiography as preoperative evaluation. Results: 1. The success rate was 91%, that in 14 cases, 13 cases were succeded. 2. To obtain successful result of peroneal flap, one must have the anatomic concept for vascular pattern, 8 cases were between peroneus muscle and soleus muscle branch type but, 3 cases were through soleus muscle branch type, so we treated these cases by using soleus muscle including peroneal perforating branch not to injury perforating artery directly. 3. The pedicle size was between minimally $2{\times}2.5cm$ and maximally $6.5{\times}8.5cm$ so we could treat large recipient site. 4. The pedicle length was between minimally 3.2 cm and maximally 11.5cm, average 7.5 cm. 5. The diameter of perforating artery was estimated by inspection, that was about 0.2-0.5 cm Conclusion: The peroneal perforating artery flap has merits that we can approach in avascular zone and has wide movable range from foot to distal femur and little donor site mobidity and can harvest osteocutaneous flap. The weak point was the irregular anatomy of nutrient artery and not to contain sensory nerve.

• Structural Engineering and Mechanics
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• 제42권1호
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• pp.121-129
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• 2012

All contemporary seismic Codes have adopted smooth design acceleration response spectra, which have derived by statistical analysis of many elastic response spectra of natural accelerograms. The above smooth design spectra are characterized by two main branches, an horizontal branch that is 2.5 times higher than the peak ground acceleration, and a declining parabolic branch. According to Eurocode EN/1998, the period range of the horizontal, flat branch is extended from 0.1 s, for rock soils, up to 0.8 s for softer ones. However, from many natural recorded accelerograms of important earthquakes, the real spectral amplification factor appears to be much higher than 2.5 and this means that the spectrum leads to an unsafe seismic design of the structures. This point is an issue open to question and it is the object of the present study. In the present paper, the spectral amplification factor of the smooth design acceleration spectra is re-calculated on the grounds of a known "reliability index" for a desired probability of exceedance. As a pilot scheme, the seismic area of Greece is chosen, as it is the most seismically hazardous area in Europe. The accelerograms of the 82 most important earthquakes, which have occurred in Greece during the last 38 years, are used. The soil categories are taken into account according to EN/1998. The results that have been concluded from these data are compared with the results obtained from other strong earthquakes reported in the World literature.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2005년도 추계종합학술대회
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• pp.481-484
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• 2005

직접 변환 방식은 혼합기를 사용하는 구조와 6-단자 회로를 사용하는 구조를 갖는다. 6-단자 회로를 사용하는 방식은 혼합기를 이용하는 방식보다 회로 구조가 간단하고 집적화도 쉬운 장점을 가지고 있다. 그리고 다이오드 작동을 위한 전압이 혼합기를 작동시키기 위한 전압보다 낮은 장점을 가지고 있으며 LO에서의 소비전력이 낮고 광대역으로 구현하기 유리한 점을 보이고 있다. 본 논문에서는 branch-line 결합기로 구성되는 6-단자 회로와 ring hybrid 결합기로 구성되는 6-단자 회로를 설계하고 성능을 비교분석하였다.

• Earthquakes and Structures
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• 제23권1호
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• pp.59-73
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• 2022

In this study, the seismic behavior of an all-steel buckling-restrained (AB) steel plate shear wall (SPSW) with incline slits under fire and cyclic loading was investigated. ABSPSW was composed of two thin steel infill plates with a narrow distance from each other, which were embedded with incline slits on each plate. These slits were in opposite directions to each other. The finite element (FE) numerical model was validated with three test specimens and after ensuring the modeling strategy, the parametric study was performed by considering variables such as wall plate thickness, slit width, strip width between two slits, and degree of temperature. A total of 256 FE numerical models were subjected to coupled temperature-displacement analysis. The results of the analysis showed that the high temperature reduced the seismic performance of the ABSPSW so that at 917℃, the load-bearing capacity was reduced by 92%. In addition, with the increase in the temperature, the yield point of the infill plate and frame occurred in a small displacement. The average decrease in shear strength at 458℃, 642℃, and 917℃ was 18%, 46%, and 92%, respectively, compared to the shear strength at 20℃. Also, with increasing the temperature to 917℃, ductility increased by an average of 75%

• Geomechanics and Engineering
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• 제13권6호
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• pp.1045-1055
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• 2017

Tensile strength is considered key properties for characterizing rock material in engineering project. It is determined by direct and indirect methods. Point load test is a useful testing method to estimate the tensile strengths of rocks. In this paper, the effects of rock shape on the point load index of gypsum are investigated by PFC2D simulation. For PFC simulating, initially calibration of PFC was performed with respect to the Brazilian experimental data to ensure the conformity of the simulated numerical models response. In second step, nineteen models with different shape were prepared and tested under point load test. According to the obtained results, as the size of the models increases, the point load strength index increases. It is also found that the shape of particles has no major effect on its tensile strength. Our findings show that the dominant failure pattern for numerical models is breaking the model into two pieces. Also a criterion was rendered numerically for determination of tensile strength of gypsum. The proposed criteria were cross checked with the results of experimental point load test.

• Journal of Oral Medicine and Pain
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• 제33권4호
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• pp.295-303
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• 2008

목적: 혀의 해부학적 위치에 따른 촉각식별능의 차이를 조사하고 이것과 심상유두의 개수 사이에 관련성이 있는지의 여부를 확인하기 위해서 본 연구를 시행하였다. 방법: 현재 복용 중인 약물이 없고, 과거 장기간 약물을 복용한 경험이 없었으며, 전신질환이 없는 건강한 남녀 13명(평균 연령 $30{\pm}3$세)을 대상으로 혀의 수초성 $A{\delta}$ 섬유와 무수초성 C 섬유와 관련한 촉각식별능을 알아보기 위해서 Castroviezo $caliper^{(R)}$를 이용한 두점식별검사를 실시하였다. 심상유두의 개수는 methylene blue로 혀를 염색해서 심상유두를 확인하여 개수를 세었다. 결과: 1. 혀의 전방부와 후측방부위의 심상유두개수를 세어 본 결과, 남자는 전방과 후측방이 각각$51.69{\pm}14.15$개, $12.92{\pm}6.13$개였으며, 여자는 $58.85{\pm}13.56$개, $16.23{\pm}6.38$개였다. 남녀 모두 후측방에 비해 전방부에서 유두의 개수가 3배 이상 많은 것을 관찰할 수가 있다. 2. 두 점으로 식별해내는 최소한의 거리는 전방에서 평균 $1.91{\pm}0.74mm$였으며, 성별에 따라 나눠 다시 분류했을 때, 남자의 인식 역치가 높은 것으로 관찰되었으나, 성별에 따른 통계적 유의성은 나타나지 않았다. 3. 두점식별거리를 기준으로 네 개의 그룹으로 나누었을 때, 거리가 증가할수록 심상유두의 개수가 감소하는 경향을 보였다. 그러나, 두점인지역치와 심상유두의 개수 간에 통계적 유의성은 없었다.

• 대한수학회논문집
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• 제35권3호
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• pp.891-906
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• 2020

In this paper, the commutative module amenable Banach algebras are characterized. The hereditary and permanence properties of module amenability and the relations between module amenability of a Banach algebra and its ideals are explored. Analogous to the classical case of amenability, it is shown that the projective tensor product and direct sum of module amenable Banach algebras are again module amenable. By an application of Ryll-Nardzewski fixed point theorem, it is shown that for an inverse semigroup S, every module derivation of 𝑙¹(S) into a reflexive module is inner.