• 한국항공운항학회지
• /
• 제15권4호
• /
• pp.24-32
• /
• 2007

In this study, computational structural vibration analyses of a smart unmanned aerial vehicle (SUAV) with tilt-rotors due to dynamic hub loads have been conducted considering detailed supporting structures of installed equipments. Three-dimensional dynamic finite element model has been constructed for different fuel conditions and tilting angles corresponding to helicopter, transition and airplane flight modes. Practical computational procedure for modal transient response analysis is successfully established. Also, dynamic loads generated by rotating blades and wakes in the transient and forward flight conditions are calculated by unsteady computational fluid dynamics technique with sliding mesh concept. As the results of present study, transient structural displacements and accelerations of the vibration sensitive equipments are presented in detail. In addition, vibration characteristics of structures and installed equipments of which safe operation is normally limited by the vibration environment specifications are physically investigated for different flight conditions.

• 한국수학사학회지
• /
• 제22권4호
• /
• pp.15-28
• /
• 2009

본 논문은 17세기 조선의 대표적인 산서(算書)인 경선징(慶善徵, 1616~?)의 ${\ll}$묵사집산법(默思集筭法)${\gg}$에 대한 연구이다. 본 연구를 통해서 ${\ll}$묵사집산법(默思集筭法)${\gg}$은 17세기의 중요한 산서(算書)로서 그 의미를 찾을 수 있으며, 또한 17세기 조선 산학의 상황을 알려주는 중요한 사료(史料)임을 알 수 있다.

• Wind and Structures
• /
• 제30권6호
• /
• pp.597-616
• /
• 2020

The blockage effect on the aerodynamic characteristics of tall buildings is a fundamental issue in wind tunnel test but has rarely been addressed. To evaluate the blockage effects on the aerodynamic forces on a square tall building and flow field peripherally, large eddy simulations (LES) were performed on a 3D square cylinder with an aspect ratio of 6:1 under the uniform smooth inflow and turbulent atmospheric boundary layer (ABL) inflow generated by the narrowband synthesis random flow generator (NSRFG). First, a basic case at a blockage ratio (BR) of 0.8% was conducted to validate the adopted numerical methodology. Subsequently, simulations were systematically performed at 6 different BRs. The simulation results were compared in detail to illustrate the differences induced by the blockage, and the mechanism of the blockage effects under turbulent inflow was emphatically analysed. The results reveal that the pressure coefficients, the aerodynamic forces, and the Strouhal number increase monotonically with BRs. Additionally, the increase of BR leads to more coherence of the turbulent structures and the higher intensity of the vortices in the vicinity of the building. Moreover, the blockage effects on the aerodynamic forces and flow field are more significant under smooth inflow than those under turbulent inflow.

• Wind and Structures
• /
• 제24권5호
• /
• pp.465-480
• /
• 2017

Modelling an equilibrium atmospheric boundary layer (ABL) in computational wind engineering (CWE) and relevant areas requires the boundary conditions, the turbulence model and associated constants to be consistent with each other. Among them, the inflow boundary conditions play an important role and determine whether the equations of the turbulence model are satisfied in the whole domain. In this paper, the idea of modeling an equilibrium ABL through specifying proper inflow boundary conditions is extended to the SST $k-{\omega}$ model, which is regarded as a better RANS model for simulating the blunt body flow than the standard $k-{\varepsilon}$ model. Two new sets of inflow boundary conditions corresponding to different descriptions of the inflow velocity profiles, the logarithmic law and the power law respectively, are then theoretically proposed and numerically verified. A method of determining the undetermined constants and a set of parameter system are then given, which are suitable for the standard wind terrains defined in the wind load code. Finally, the full inflow boundary condition equations considering the scale effect are presented for the purpose of general use.

• Asian Pacific Journal of Cancer Prevention
• /
• 제14권12호
• /
• pp.7439-7444
• /
• 2013

Aim: ATF3, a member of the ATF/CREB family of transcription factors, has been found to be selectively induced by calcineurin/NFAT inhibition and to enhance keratinocyte tumor formation, although the precise role of ATF3 in human skin cancer and possible mechanisms remain unknown. Methods: In this study, clinical analysis of 30 skin cancer patients and 30 normal donors revealed that ATF3 was accumulated in skin cancer tissues. Functional assays demonstrated that ATF3 significantly promoted skin cancer cell proliferation. Results: Mechanically, ATF3 activated Stat3 phosphorylation in skin cancer cell through regulation of p53 expression. Moreover, the promotion effect of ATF3 on skin cancer cell proliferation was dependent on the p53-Stat3 signaling cascade. Conclusion: Together, the results indicate that ATF3 might promote skin cancer cell proliferation and enhance skin keratinocyte tumor development through inhibiting p53 expression and then activating Stat3 phosphorylation.

• 사상체질의학회지
• /
• 제9권1호
• /
• pp.273-297
• /
• 1997

The objective of this article is to carry on the comparative study of the two books, Dongyisusebowon and Myungsunrok. Je-Ma Lee showed, in fact, the intellectual achievement in his book, Dongyisusebowon. And Lee showed more close relationships with Suk-Ji Han's idea. The common ideas from this comparative study of both scholars are as follows. 1. Lee understands the real character of human being according to Chu-Ztu(朱子)'s doctrine, with the supplement of Han's. 2. Lee explains the Sung-Jung(性情) in Cosmology and the theory of Human Nature, but he concentrates upon the Sung-Jung in the theory of Human Nature, especially in constitutional medicine. 3. Lee states the Tai-Geuk(太極) in the meaning of heart from the medical viewpoint, he agrees with the Han's idea. 4. I try to comprehend Myungsunrok in the Wang-Yang-Ming(王陽明)'s concept. 5. Han explains that Sung-Jung-I-Ki(性情理氣) is one concept with two aspects, Che-Yong(體用). In addition, Lee has formed his 'Chun-In-Sung-Myung(天人性命)' thought in harmonization with Han's idea and Chu-Tzu's idea.

• 한국임상수의학회지
• /
• 제16권2호
• /
• pp.397-403
• /
• 1999

This study was designed to examine the clincotherapeutic effect of natural honeybee (Apis mellifera) venom in sows with mastitis, metritis and agalactia (MMA) syndrome. Sows with MMA syndrome after parturition were assigned to treated and nontreated control groups. In treated group, 22 sows were bee acupunctured once a day for 3 consecutive days. Acupuncture points of Jiao-chao (GV-1, at the indentation between the base of tail and the anus), Yang-ming (ST-18, outside at the base of teat) and Hai-men (ST-25, about 1 cm lateral to the umbilicus) were stung by the natural honeybees. In control group, 20 sows were intramuscularly injected with a standard dosage of penicillin G (400,000 IU/kg of body weight) once a day for 3 consecutive days. At post-treatment, 85.0% of control sows and 90.9% of sows in treated group recovered from MMA syndrome. Bee acupuncture therapy didn't show any side effects such as allergy, intoxication, hemorrhage, or infection. It might be concluded that apitherapy was effective in controlling of sows with MMA syndrome.

• Journal of Power Electronics
• /
• 제13권5호
• /
• pp.746-756
• /
• 2013

The modularized subunit of an electronic power transformer (EPT) is a series connection of two H-bridge voltage-source converters and a DC-DC converter with a high-frequency isolation transformer (HFIT). On the basis of cascading and paralleling the modularized subunits, EPT can be used in high-voltage and large-current applications in the power system. This paper discusses the steady state analysis of the modularized subunit of EPT. Theoretical analysis considers the influences of the two H-bridge voltage-source converters on the two sides of the DC-DC converter. We deduce the formulas of the theoretical calculation on the internal electrical characteristics of EPT (e.g., the voltages of the DC-bus capacitor and the primary side peak current of the HFIT). This paper provides guidance on the design and selection of EPT key elements (e.g., the DC-bus capacitors and HFIT). Experimental results are obtained from a single subunit of a laboratory model rated at 962 V, 15 kVA. All calculations, simulations, and experiments confirm the theoretical analysis of the subunit of EPT.

• 대한기계학회논문집A
• /
• 제33권4호
• /
• pp.296-309
• /
• 2009

Thick-walled cylinder with high pressure have had wide application in the armament industry. In the thick-walled cylinder, fatigue crack is generated at inner radius and developed toward the outer radius. To prevent generation of fatigue crack, the autofrettage process had been used. The compressive residual stress induced by the autofrettage process extends loading pressure and fatigue life of the thick-walled cylinder. In this study, the residual stress of single and compound cylinder by the autofrettage process was evaluated. The analytical compressive residual stress of single cylinder was good agreement with experimental result at inner radius. The analysis on the residual stress of compound cylinder was conducted. The compressive residual stress at inner radius was increased with the overstrain level. And fatigue life of the compound cylinder with initial crack was evaluated. The considered initial crack shape was straight and semi-elliptical. The fatigue life was extended with the overstrain level. The fatigue life of the compound cylinder with semi-elliptical crack was longer than straight crack. The suitable way to extend fatigue life of the compound cylinder was proposed.

• Asian Pacific Journal of Cancer Prevention
• /
• 제15권17호
• /
• pp.7159-7162
• /
• 2014

Background: Patients with recurrent or refractory osteosarcoma are considered to have a very poor prognosis, and new regimens are needed to improve the prognosis in this setting. Gemcitabine, a nucleoside antimetabolite, is an analog of deoxycytidine which mainly inhibits DNA synthesis through interfering with DNA chain elongation and depleting deoxynucleotide stores, resulting in gemcitabine-induced cell death. Here we performed a systemic analysis to evaluate gemcitabine based chemotherapy as salvage treatment for patients with recurrent or refractory osteosarcoma. Methods: Clinical studies evaluating the impact of gemcitabine based regimens on response and safety for patients with osteosarcoma were identified by using a predefined search strategy. Pooled response rates (RRs) of treatment were calculated. Results: In gemcitabine based regimens, 4 clinical studies which included 66 patients with recurrent or refractory osteosarcoma were considered eligible for inclusion. Systemic analysis suggested that, in all patients, pooled RR was 12.1% (8/66) in gemcitabine based regimens. Major adverse effects were hematologic toxicity, including grade 3 or 4 anemia, leucopenia and thrombocytopenia in gemcitabine based treatment. No treatment related death occurred in gemcitabine based treatment. Conclusion: This systemic analysis suggests that gemcitabine based regimens are associated with mild activity with good tolerability in treating patients with recurrent or refractory osteosarcoma.