• Structural Engineering and Mechanics
• /
• 제17권6호
• /
• pp.789-817
• /
• 2004

This paper deals with the modal analysis of rotational shell structures by means of the numerical solution technique known as the Generalized Differential Quadrature (G. D. Q.) method. The treatment is conducted within the Reissner first order shear deformation theory (F. S. D. T.) for linearly elastic isotropic shells. Starting from a non-linear formulation, the compatibility equations via Principle of Virtual Works are obtained, for the general shell structure, given the internal equilibrium equations in terms of stress resultants and couples. These equations are subsequently linearized and specialized for the rotational geometry, expanding all problem variables in a partial Fourier series, with respect to the longitudinal coordinate. The procedure leads to the fundamental system of dynamic equilibrium equations in terms of the reference surface kinematic harmonic components. Finally, a one-dimensional problem, by means of a set of five ordinary differential equations, in which the only spatial coordinate appearing is the one along meridians, is obtained. This can be conveniently solved using an appropriate G. D. Q. method in meridional direction, yielding accurate results with an extremely low computational cost and not using the so-called "delta-point" technique.

• Bulletin of the Korean Chemical Society
• /
• 제32권10호
• /
• pp.3644-3649
• /
• 2011

Multinuclear solid-state nuclear magnetic resonance (NMR) experiments were performed to investigate the local structure changes of nanoporous silica during hydrothermal treatment and surface modification with 3-aminopropyltriethoxysilane (3-APTES). The nanoporous silica was prepared by sol-gel polymerization using inexpensive sodium silicate as a silica precursor. Using $^1H$ magic angle spinning (MAS) NMR spectra, the hydroxyl groups, which play an important role in surface reactions, were probed. Various silicon sites such as $Q^2$, $Q^3$, $Q^4$, $T^2$, and $T^3$ were identified with $^{29}Si$ cross polarization (CP) MAS NMR spectra and quantified with $^{29}Si$ MAS NMR spectra. The results indicated that about 25% of the silica surface was modified. $^1H$ and $^{29}Si$ NMR data proved that the hydrothermal treatment induced dehydration and dehyroxylation. The $^{13}C$ CP MAS and $^1H$ MAS NMR spectra of 3-APTES attached on the surface of nanoporous silica revealed that the amines of the 3-aminopropyl groups were in the chemical state of ${NH_3}^+$ rather than $NH_2$.

• 열처리공학회지
• /
• 제32권6호
• /
• pp.270-274
• /
• 2019

In this study, simulation structure analysis was performed for the differential gear system for passenger cars as a prerequisite for the design of the balancing module. The differential gear system was modeled by using CATIA and simulation structure analysis was performed using ANSYS software. The material of the modeled differential gear system uses the mechanical properties of S45C (Q&T). In the structural analysis of the differential gear, the areas where the maximum stress and the maximum strain occurred can be identified. The maximum stress and maximum strain occurred in the pitch circle of the bevel gear. In evaluating the safety factor, it was found that sufficient safety factor was secured. Based on the analysis results for the differential gear, it is expected that it will be a good reference if we design the balancing module device.

• Asian Pacific Journal of Cancer Prevention
• /
• 제14권8호
• /
• pp.4835-4838
• /
• 2013

Background: We compared treatment completion rates and safety of docetaxel and cyclophosphamide sixcycle therapy (TC6) with docetaxel followed by 5FU, epirubicin and cyclophosphamide (T-FEC) therapy in Japanese patients with human epidermal growth factor receptor 2 (HER2)-negative breast cancer. Materials and Methods: We administered TC6 q3w or T-FEC q3w to HER2-negative breast cancer patients. The primary endpoint of this trial was toxicity. As second endpoints, the treatment completion rate and relative dose intensity were evaluated. Results: The TC6 and T-FEC group consisted of 22 and 21 patients, respectively. Concerning hematological toxicity, grade 3 or higher adverse reactions included neutropenia and febrile neutropenia. As non-hematological adverse events, exanthema and peripheral neuropathy were frequently reported in the TC6 group, whereas more patients of the T-FEC group reported nausea and vomiting. In TC6, the treatment completion rate was 86.4% and the relative dose intensity of docetaxel was 93.2%. In T-FEC, the values were 95.2% and 98.9%, respectively. Conclusions: These results suggest that TC6 is tolerable in Japanese, and that this regimen can also be performed in outpatient clinics. However, with the TC6 regimen, the compliance was slightly lower than with the T-FEC regimen, and supportive therapy needs to be managed appropriately.

• 한국주조공학회지
• /
• 제41권6호
• /
• pp.528-534
• /
• 2021

본 연구는 Al-Mg-Si 합금에서 Cu가 첨가 후 자연시효와 인공시효에 따른 제2상 석출 반응이 합금의 열확산도 및 경도에 미치는 영향을 연구하였다. 연구에 사용된 Al-0.4Mg-0.2Si 합금과 Cu를 0.6 wt%, 1.0wt% 추가한 Al-Mg-Si-Cu 합금을 각각 중력 주조로 제작하고 열확산도 경도를 측정하고 석출 반응을 확인하기 위해 열량 분석을 실시 하였다. Al-Mg-Si 합금에 첨가된 Cu는 Q'상 및 θ'상과 같은 강화상 형성에 참여하여 합금의 경도와 고온 열확산도를 향상시켰다. 한편, 자연시효 시간 증가는 Al-Mg-Si-Cu 합금의 열확산도에는 큰 영향을 미치지 않았으나, 경도를 하락시키는 것으로 확인되었다.

• Journal of Welding and Joining
• /
• 제5권3호
• /
• pp.28-37
• /
• 1987

To clarify the debonding phenomena of clad steel, the effect of thermal treatment (temperature, holding time) on the interfacial strength of clad steel was preliminarily investigated. From this study, it was confirmed that the interfacial strength of clad steel was deteriorated by thermal treatment and the amount of strength deteriorated, depending on the condition of thermal treatment, could be evaluated by the following equation. ${\sigma}_{ HT}/{\sigma}_{i}/=A_{0}-A\;exp(-Q/RT)log(t/t_{0})$ This equation implies that temperature has a far strong effect on strength deterioration than tiem. The deterioration of interfacial strength of clad steel after thermal treatment may be derived from the thermal stress caused by the difference in thermal expansion coefficient between component materials and microstructural change along the interface.

• Clinical and Experimental Reproductive Medicine
• /
• 제46권3호
• /
• pp.112-118
• /
• 2019

Objective: Oxidative stress contributes to male infertility, and antioxidants have been recommended for treating idiopathic oligoasthenoteratozoospermia (OAT). There is, however, a lack of agreement on the type, dosing, and use of individual antioxidants or combinations thereof. The purpose of this study was to compare the effects of two doses of coenzyme Q10 (CoQ10) on semen parameters and antioxidant status in men with idiopathic OAT. Methods: In this prospective study, patients with idiopathic OAT received 200 mg/day (n = 35) or 400 mg/day (n = 30) of CoQ10 orally for 3 months. All patients underwent semen analysis according to the fifth editions of the World Health Organization criteria. Total antioxidant capacity (TAC), catalase (CAT) activity, and superoxide dismutase (SOD) activity were measured both before and after treatment. Results: Treatment with CoQ10 (200 mg/day or 400 mg/day) resulted in a significant increase in sperm concentration from baseline ($8.22{\pm}6.88$ to $12.53{\pm}8.11million/mL$, p= 0.019; $7.58{\pm}5.41$ to $12.33{\pm}6.1million/mL$, p= 0.002, respectively), progressive motility ($16.54%{\pm}9.26%$ to $22.58%{\pm}10.15%$, p=0.011; $14.22%{\pm}12.85%$ to $26.1%{\pm}14.52%$, p= 0.001, respectively), and total motility ($25.68%{\pm}6.41%$ to $29.96%{\pm}8.09%$, p= 0.016; $23.46%{\pm}12.59%$ to $34.82%{\pm}14.17%$, p= 0.001, respectively). CoQ10 therapy also increased TAC (p= 0.009, p= 0.001, respectively), SOD activity (p= 0.004, p= 0.001, respectively), and CAT activity (p= 0.039, p= 0.024, respectively). Furthermore, antioxidant measures correlated significantly with seminal fluid parameters (r = 0.36-0.76). Conclusion: CoQ10 supplementation improved semen parameters and antioxidant status in men with idiopathic OAT, with a greater improvement shown in men who took 400 mg/day than in those who took 200 mg/day.

• 한국환경복원기술학회지
• /
• 제15권3호
• /
• pp.67-74
• /
• 2012

This study was carried out to cultivate evergreen-leaved tree container seedlings having low cost of equipment and easy to control. Two species of V. odoratissimum var. awabuki and Q. glauca planting in respective underground container were showed survival rate above 90%. The Relative growth rates of height was good in non-treatment and root collar diameter was no significant difference between treatments. The T/R ratio was respectively 1.1, 1.0 in container type of F, G. and root's biomass products was more effective than others. A container type of F showed better Quailty index than others with 16.2 values. Q. glauca was higher T/R ratio in root development than shoot and the quality index was high in container type of E, D with 4.0. 3.5, respectively. On the basis of the results obtained in this study, we can concluded that the underground container type was suitable to F in V. odoratissimum var. awabuki and to D or E in Q. glauca.

• Journal of Plant Biology
• /
• 제37권1호
• /
• pp.37-42
• /
• 1994

Correlative changes between photosynthetic O2 exchange rates and room temperature Chl fluorescence were investigated in wheat (Triticum aestivum L.) chloroplasts treated with high temperature for 5 min. With increasing treatment temperature, photosynthetic O2 evolution rate mediated by PSII was decreased, showing 50% inhibition at 38$^{\circ}C$ (I50). But PSI activity measured by O2 uptake rates was stimulated as a function of increasing temperature. Dark level fluorescence (Fo)-temperature (T) analysis showed that fluorescence rising temperature (Tr), critical temperature (Tc), and peak temperature (Tp) was 38, 43, and 52$^{\circ}C$, respectively. Quenching analysis of Chl fluorescence showed that both the oxidized fraction of plastoquinone (qQ) and degree of thylakoid membrane energization (qNP) increased up to 4$0^{\circ}C$ and then declined dramatically. These results suggest that Tr is correlated with temperature showing a 50% of inhibition of photosynthesis and under mild high temperature stress, qNP is worth regarding as indicator for heat-induced damage of photosynthesis.

• 전기학회논문지
• /
• 제63권7호
• /
• pp.950-955
• /
• 2014

In this paper, we propose a drug treatment protocol for the three state HIV infection model that explicitly includes the concentration of healthy T cells, infected T cells, and HIV. While most of the previous methods are not able to achieve the treatment goal in the presence of modelling errors, the proposed method is designed so as to compensate for the model uncertainties. Based on the Jacobain linearization of nonlinear HIV infection model, disturbance observer(DOB) based control is employed to design the drug treatment for the HIV patients. Computer simulation is carried out for nonlinear model in order to compare the performance of the proposed method with that of the conventional technique. The simulation results show that, in the presence of parameter uncertainties, the substantial improvement in the performance can be achieved by the proposed DOB controller.