• Steel and Composite Structures
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• 제19권6호
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• pp.1599-1610
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• 2015

Cold Formed Steel members are widely used in today's construction industry. However the structural behavior of light gauge high strength cold formed steel sections characterized by various buckling modes are not yet fully understood. Because of their simple forming and easy connections, the commonly used cold formed sections for beams are C and Z. However both these sections suffer from certain buckling modes. To achieve much improved structural performance of cold formed sections for beams both in terms of strength and stiffness, it is important to either delay or completely eliminate their various modes of buckling. This paper presents various innovative sectional profiles and stiffening arrangements for cold formed steel beams which would successfully contribute in delaying or eliminating various modes of premature buckling, thus considerably improving the load carrying capacity as well as stiffness characteristics of such innovative cold formed sections compared to conventional cold formed steel sections commonly used for beams.

• Computers and Concrete
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• 제8권4호
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• pp.473-489
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• 2011

In designing a flexural member for structural safety, both the flexural strength and ductility have to be considered. For this purpose, the flexural ductility of reinforced concrete sections has been studied quite extensively. As there have been relatively few studies on the flexural ductility of prestressed concrete sections, it is not well understood how various structural parameters affect the flexural ductility. In the present study, the full-range flexural responses of reinforced and prestressed concrete sections are analyzed taking into account the nonlinearity and stress-path dependence of constitutive materials. From the numerical results, the effects of steel content, yield strength and degree of prestressing on the yield curvature and ultimate curvature are evaluated. It is found that whilst the concept of flexural ductility in terms of the ductility factor works well for reinforced sections, it can be misleading when applied to prestressed concrete sections. For prestressed concrete sections, the concept of flexural deformability in terms of ultimate curvature times overall depth of section may be more appropriate.

• Nuclear Engineering and Technology
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• 제55권11호
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• pp.4026-4031
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• 2023

In this article, we report a new empirical formula for quick calculation of cross sections of (n, α) reactions with 14-15 MeV neutrons. Cross sections are analysed in terms of the compound nucleus model. A systematic trend for 14-15 MeV neutrons is found in the variation of (n, α) reaction cross sections with the parameters (N - Z + 1), (E_n + Q)^0.5 and N/Z. The empirical relation between the cross sections and these parameters has been obtained, which give fairly good fits with the experimental data. We have also investigated the odd-even effects on (n, α) cross sections considering binding energy systematic of the shell model. The present formula is very useful in predicting of the (n, α) cross sections, where the measurements are not available as well as in testing new experimental data.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2004년도 봄 학술발표회 논문집
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• pp.325-331
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• 2004

Generally, the buckling of thin-walled structures has studied for rectangular sections or circular sections. Rectangular sections have small stiffness and circular sections have large stiffness when they are compared with rectangular sections for local buckling. But both of them have similar stiffness to column buckling. Therefore in this paper, we are going to analyze the local buckling for the box section with rounded comer and compare with rectangular section. Also we confirm that the rounded comer section has larger local buckling strength than rectangular section.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.53-58
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• 2001

Composite boundary elements with H steel sections could be used to enhance the strength and ductility of high-rise shear walls. The enhancement of earthquake resistance is expected to be achieved due to the inherent strength and ductility of the steel sections, and also due to the confinement effect to a core concrete. Experimental study were peformed for the compression zone of composite shear walls with multiple H sections at the boundaries. The effect of the steel sections on the overall behavior of the composite shear walls were investigated. Also, additional tests were conducted to investigate the contribution of H sections to the confinement of concrete.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.34-34
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• 2010

Absolute electron-impact cross sections for molecular targets including their radicals are important in developing plasma reactors and testing various plasma processing gases. However, low-energy electron collision data for these gases are sparse and only the limited cross section data are available. In this presentation, the methods and the status of measurements of, mainly, absolute elastic cross sections for electron-polyatomic molecule collisions will be discussed with recent results from Chungnam National University. Elastic cross sections are essential for the absolute scale conversion of inelastic cross sections, as well as for testing computational methods.

• Asian Pacific Journal of Cancer Prevention
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• 제13권8호
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• pp.3675-3680
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• 2012

Objective: To investigate the expression of endogenous hypoxia-related markers identified as being involved in vulvar squamous cell carcinoma (VSCC). Methods: We performed immunohistochemical staining of hypoxia-inducible factor-$1{\alpha}$ (HIF-$1{\alpha}$), glucose transporter-1 (GLUT-1), carbonic anhydrase 9 (CA-9) and vascular endothelial growth factor (VEGF), on tissue sections of 25 VSCC patients, 10 vulvar intraepithelial neoplasia (VIN) patients and 12 healthy controls. Results: HIF-$1{\alpha}$ expression was found in all sections, with no significant difference between controls, VIN and VSCC sections (all P<0.05). Glut-1 expression was found in 25% of control, 90% of VIN and 100% of VSCC sections. A significant difference between control and VIN or VSCC was observed (all P<0.05), while no difference was found between VIN and VSCC sections (P>0.05). CA-9 expression was negative in control sections, but it was found in 30% of VIN sections and 52% of VSCC sections with strong staining. Similarly, CA-9 expression also showed obvious differences between controls and VIN or VSCC sections (all P<0.05). However, there was no significant difference between VIN and VSCC (P>0.05). There were only 25% of control sections with weak VEGF expression, while strong staining was found in about 60% of VIN sections and 25% of VSCC sections (all P<0.05). In addition, a difference was also found between VIN and VSCC sections (P<0.05). Conclusion: Expression of endogenous hypoxia markers (HIF-$1{\alpha}$, GLUT-1, CA-9 and VEGF) might be involved in the malignant progression of VSCC.

• 건축역사연구
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• 제17권1호
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• pp.85-102
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• 2008

As a result of analyzing the floor plan shown in the three drafts, there were a great deal of differences in composing the space of the inner main hall. The inner room facing to the east with the arrangement crossing the inner floor at right angles in the 'Baekdangguje Draft' faces to the south in the east or west in front of the main house thereafter. This represents that it reflects the intent of the owner of the architecture emphasizing the size increase and ceremonies of the main house in the 'ㅁ shape', which has changed to the directions of easily accommodating the Confucian ceremonial activities in the floor plan of the inner house as the size of the main house was gradually increasing from 24 sections to 30 or 38 sections. The expansion in the size of main house further divided the functions of floor into one for daily life and the other for ceremonies as well. In other words, the 30 Sections in Yijeong Draft as being the first planned draft for reconstruction had a hall for memorial services in the main hall of the inner house, whereas the 'Draft with 38 Sections' as being the second planned draft for reconstruction was planning a room with a floor (two sections of Bangdang) for memorial purpose in the back of the inner main hall. The variations in the guest house (or space for men) shown in the drafts confirms the establishment of space for men as the size of the main house increases. We can see the change that a large guest house is placed over the south and in the south and east of the main house as the number of main house increases by 30 sections or 38 sections. Especially, a guest house with a wide space in a 'ㄴ shape' is arranged from the south of main house to the east wing in the Draft with 38 Sections. In addition, the backward sections are advanced in the front and back of guest house in the drafts with 30 and 38 sections, while a back floor or a back floor connecting to the back room or sleeping room or inner house is installed in the backward sections.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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• pp.113-116
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• 2006

In this paper, the fairing effects on the aerodynamics stability of basic plate-girder sections are investigated trough wind tunnel tests. As basis sections, two types of $\pi$-type shape sections with aspect ratios(D/B) of 1/5 and 1/10 are employed as the basic sections. And three types of triangular fairings are applied such as right-angled triangle(F1), inverted right-angled triangle(F2) and regular triangle(F3). The effects of attack angle on the dynamic response of each section are also investigated. As the results of experiments, fairings F2 is most effective to suppress flutter phenomenon or vortex induced vibration among three types of fairings.

• East Asian mathematical journal
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• 제28권4호
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• pp.453-474
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• 2012

The conic sections is an important topic in the current high school geometry. It has been recognized by many researchers that high school students often have difficulty or misconception in the learning of the conic sections because they are taught the conic sections only with algebraic perspective or analytic geometry perspective. In this research, we suggest a way of teaching the conic sections using a dynamic geometry software based on some mathematics teaching and learning theories such as Freudenthal's and Dienes'. Students have various experience of constructing and manipulating the conic sections for themselves and the experience of deriving the equations of the quadratic curves under the teacher's careful guidance. We identified this approach was a feasible way to improve the teaching and learning methods of the conic sections.