• Steel and Composite Structures
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• v.50 no.1
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• pp.1-13
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• 2024

The objective of this research is to study experimentally and numerically the behavior of steel beam columns with openings. Although the presence of openings in the beam columns is inevitable, finding ways to maintain strength is crucial. The studied parameters are opening shape, the ratio between opening height to specimen height, the percentage of opening location from support to beam column length, and web slenderness. Experimental tests are conducted including twelve specimens to study the effect of these parameters and record failure load, load deflection curve, and stress strain curve. Two failure modes are observed: local and flexural buckling. Interaction curves plotted from finite element model analysis are also used to expand the parametric study. Changing the location of the opening can decrease failure load by up to 7% and 60% in both normal and moment ratios respectively. Increasing the opening dimension can lead to a drop in the axial ratio by up to 29% and in the moment ratio by up to 74%. The weakest beam column behavior is noticed in specimens with rectangular openings which results from uneven and concentrated stresses around the opening. The main results of this research illustrate that the best location for opening is at 40% - 50% from beam column support. Also, it is advisable to use circular openings instead of rectangular openings in specimens having slender webs because moment ratios are raised by 85% accompanied by a rise in normal ratios by 9%.

• Journal of the Korea institute for structural maintenance and inspection
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• v.3 no.3
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• pp.213-222
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• 1999

On condition that opening located at high shear strength position in H-shaped steel beams with web opening, beams are structurally to be frailed so necessity and efficiency of vertical reinforcement to add horizontal reinforcement already published ahead study. Up to the present study of web opening beams, limited one opening which located in comparatively small shear strength position. But frequently opening area is enlargement by necessity, so width of opening is larger by limit of depth or increasing number of opening. This study carry out experiment to make efficient reinforcing method about strength and deformation of steel beams with web openings. Parameters of this study are openings location, ratio of opening width within opening height and various reinforcing types.

• International Journal of Aerospace System Engineering
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• v.4 no.2
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• pp.5-9
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• 2017

In a pressurized fuel supply system of aircraft, a flow passage opening device is required to keep fuel continuously transferred from one tank to the other. The device utilizes balancing weights in order to follow up an acceleration at special conditions such as negative g. It is very difficult to test the device in a real high-speed and high-altitude test since severe test conditions and expensive supports are needed. Therefore, this paper deals with performance analysis of a flow passage opening device through low speed aircraft captive flight tests (CFT) including roll and negative-g maneuvers. It is shown that balancing weights in the device can open the passage in accordance with fuel position.

• Journal of the Korean Society of Clothing and Textiles
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• v.5 no.2
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• pp.63-68
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• 1981

Succeding to Report I, to determine the effect of opening conditions and areas of clothes ($10\%,\;20\%,\;30\%,\;40\%$ of total area) on the warmth keeping properties, cooling method was employed by using Latin Square Design, The following results were obtained: 1) The warmth keeping ratio was varied with the opening conditions and the: order was downward, upward, horizontal and up & downward opening 2) The size of opening areas was in inverse proportion to the warmth keeping ratio, 3) In the horizontal opening, the thickness of air layers in clothes did not effect on the warmth keeping ratio.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10b
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• pp.891-896
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• 2000

It is necessary to drill new opening in an existing R.C beam either for service ducts and pipes or the determination of in place concrete strength. Therefore, to simulate in this study, 18-R.C beams were fabricated with circular openings. The major parameters considered are the sizes, location of opening and cut-off stirrup. These beams are tested shear failure and capacity under a point loading. The sizes of opening are changed 0.11, 0.2, 0.3 times of beam-depth and the locations of opening are divided into $X_1$ zone, $X_2$ zone, $X_3$zone. Loads are applied up to failure to observe the cracking initiation and propagation, initial diagonal cracking, midspan deflection. As a result, the sizes of opening with 0.11D and 0.2D in R.C beams without cutoff stirrup are profitable in $X_1$ and $X_3$zone. R.C beams with 0.3D and cutoff stirrup are advantageous in $X_3$zone.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.4
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• pp.270-274
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• 2010

Introduction: Limited mouth opening is a representative clinical symptom of temporomandibular disorders (TMD) with anterior disc displacement without reduction (ADDWOR). Various treatment methods have been proposed for patients with ADDWOR. This study examined the clinical effectiveness of template therapy for patients with mouth opening difficulty due to the ADDWOR. Material and Methods: A total of 14 patients (female 12, male 2, average age: $29.1{\pm}14.4$), who had been treated in the template clinic, Sooncheonhyang University Bucheon Hospital, from January of 2006 to December of 2008, were enrolled in this study. The subjects were selected according to the following criteria: more than 2 weeks after the onset of locking, mouth opening range <35 mm, and confirmed ADDWOR without a synovial pathology by magnetic resonance imaging (MRI). All patients were treated with the template appliance, instructed to wear it while sleeping and exercise for at least 10 hours per day. The maximum mouth opening (MMO) range and pain recognition scores before and after template therapy were recorded and compared. A paired t-test and Wilcoxon's signed rank test were used for statistical analysis. Results: After the periodical follow up, significant improvement in the opening range was observed in the template treatment group. The average MMO range before treatment was $30.2{\pm}3.5mm$ and the average MMO after treatment and follow up was $47.1{\pm}4.7mm$. The mean amount of mouth opening increment was $16.9{\pm}5.4mm$ (P<0.01) and the pain recognition scores before and after treatment was also improved.(P=0.001) Conclusion: The template appliance proved to be efficient for the treatment of TMD with a closed lock and painful joint due to ADDWOR.

• Journal of the Economic Geographical Society of Korea
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• v.19 no.1
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• pp.122-142
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• 2016

This paper examines the implications of North Korea's Special Economic Zone (SEZ) strategy since the early 1990s in terms of the shifts in both North Korea's economic system and geopolitical order on the Korean peninsula. Specifically, it analyzes the shifts in North Korea's SEZ policy in three different aspects-North Korea's unique territorial logic, stress on decentralization, and comparison with Chinese reform and opening-up. Based upon this analysis, this paper criticizes a linear approach to understand North Korea's economic transformation from isolation to opening-up, and explores the dynamics of North Korea SEZ strategy in various dimensions. It contends that North Korea's SEZ strategy is neither an inevitable choice from economic difficulty nor an adoption of Chinese model of reform and opening up. Rather this paper focuses on the geopolitical logic and local development imperatives underlying SEZ strategy.

• Physical Therapy Korea
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• v.23 no.3
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• pp.29-39
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• 2016

Background: In the treatment of temporomandibular joint (TMJ) disorder, the goals of traditional physical therapy are not only to reduce the inflammatory process leading to pain, but also to decrease joint overload and muscle hyperactivity. To achieve those goals, physical therapists generally use a photo-therapy, joint mobilization, and massage. Objects: To examine the impact of an unloading technique using non-elastic taping on the pain, opening mouth, functional level, and quality of life in patients with TMJ disorder. Method: Twenty patients with TMJ disorder were included in this study and randomly divided into the experimental ($n_1$=10), and control ($n_2$=10) groups. Traditional physical therapy including massage and stretching for 30 min was performed in both groups. Non-elastic taping was performed in the experimental group after traditional physical therapy, and they were recommended to keep the tape attached for 12 hours. Outcomes for pain, functional level, and quality of life were measured using a survey. The opening mouth was measured using a general ruler. Result: Significant differences were observed in the pain level, opening mouth, functional level, and quality of life after the intervention and on follow-up in both groups. However, we found that while the levels of all parameters were maintained throughout the follow-up period in the experimental group, the functional status level was not maintained throughout the follow-up period in the control group. Conclusion: Our unloading technique using non-elastic tape results comparable to those achieved by traditional physical therapy in the treatment of TMJ. However, the unloading taping method using non-elastic tape is more effective than traditional physical therapy in maintaining the impact of intervention.

• Bulletin of the Korean Chemical Society
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• v.29 no.2
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• pp.313-318
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• 2008

An enantioselective ring opening of racemic terminal epoxides has been achieved by using heterobimetallic cobalt salen complexes with variety of nucleophiles. They were proven to be highly enantioselective and reactive for the synthesis of valuable chiral building blocks in enantio-riched forms up to 98% ee.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.10
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• pp.187-193
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• 1999

Dimensional difference by welding deformation is usually occurred at steel bridge manufacturting or multi-pass welding used at joining of thick plates. Be this, root gap out of standard is frequently developed at butt weld joints. For example, although standard root gap below 6mm at butt weld joints of plates under 15mm thickness, maximum 30mm root opening is developed at the weld field. At this case, 24mm parts out of standard is generally built up. But, there are no accumulated data and restriction about this built up welding pars. In this study, therefore, the accumulation of data for built up parts and the verification of the mechanical properties of weld part as root gap is performed. It is included that tensile, bending, impact, hardness test and microstructural review for each welding specimen of 0mm, 6mm, 30mm root opening.