• 대한물리치료과학회지
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• 제18권2호
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• pp.41-49
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• 2011

Purpose: The purpose of this study is to acknowledge the effects that have the strength exercise done only on the neck extensor, only on the thoracic extensor, and both the neck and the thoracic extensor on forward head posture(FHP) and cervical range of motion. Also is to discover which of the exercise is the most effective. Method: This experiment will be done by selecting 40 people who have 16cm or more FHP and they will be divided into four groups: three experimental groups and a control group. The first experimental group will do only the neck extensor strength exercise(NESE). The second experimental group will do only the thoracic extensorstrength exercise(TESE) and the third experimental group will do both the NESE and the TESE. The experimental groups will make a day three times each ten sets of extensor isometric strength exercise but the time will be increased from 4 to 6 and8 seconds until it will be done the ten sets. Then after four weeks, they will be compared which had the best results for the FHP and the cervical range of motion. Result: After the experiment, it was compared the experimental groups with the control group. Every experimental group had an improvement on their FHP and cervical range of motion. However, the only NESE and the only TESE did not have a significantly difference(p>.05). Only the group who did both the NESE and the TESE had a sign ificantly improvement compared to the control group. Conclusion: 1. The only NESE and the only TESE seem that had a positive effect on FHP and cervical range of motion. However, it cannot be conclude that it is effective. 2. When both the NESE and the TESE are done, it is showed statistically a significant difference(p<.05) on FHP and cervical range of motion. The refore, it would be note worthy if this exercise is used to improve the FHP and the cervical range of motion.

• 한국세라믹학회지
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• 제44권7호
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• pp.381-386
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• 2007

A porous reaction bonded silicon carbide (RBSC) was fabricated by a molten Si infiltration method. The porosity and flexural strength of porous RBSC fabricated in this study were dependent upon the amount of carbon source used in the SiC/carbon preform as well as the amount of Si infiltrated into the SiC/carbon preform. The porosity and flexural strength of porous RBSC were in the range of $20 vo1.{\sim}49 vo1.%$ and $38{\sim}61 MPa$, respectively. With increase of carbon contents and molten Si for infiltration, volume fraction of the pores was gradually decreased, and flexural strength was increased. The porous RBSCs fabricated with the same amount of molten Si show less residual Si around neck with increase of carbon source, as well as a new SiC was formed around neck which resulted in the decreased porosity and improvement of the flexural strength. In addition, decrease of the porosity and increase of the flexural strength were also obtained by increase of the amount of molten Si with the same amount of carbon source. However, it was found that the flexural strength of porous RBSC depends on the porosity rather than the amount of the newly formed SiC in neck phase between SiC particles used as a starting material.

• 대한물리치료과학회지
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• 제26권3호
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• pp.57-69
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• 2019

Background: The purpose of this study was to compare and analyze the effects of neck and trunk combined exercise program and single exercise on neck angle and neck and shoulder muscle activity. Design: Randomized controlled trial. Methods: In the single exercise group, the basic stretching, head bending and neck bending exercises were performed. The neck and trunk combined exercise group performed torso strength and trunk stability exercises to stabilize the trunk, and then performed the same neck exercise as the single exercise group. The exercise program was conducted 5 days per week for 2 weeks. One-way repeated ANOVA was used to investigate the statistical analysis of neck angle, neck and upper and middle trapezius muscle activity. Results: 1) There was no significant difference in neck angle degree after exercise in neck single exercise group. 2) In the neck and trunk combined exercise, the neck angle degree decreased continuously with the increase of the experimental period and showed a significant difference. 3) In the single exercise group, the muscles which showed significant difference compared to the post-exercise were the right upper, left and right middle trapezius. 4) In the neck and trunk combined exercise group, the right neck muscles showed significant difference after the exercise before the experiment. Conclusion: It was found that the neck and trunk combined exercise was more effective in reducing neck angle and the muscle activity of the subjects with forward head posture was decreased and increased. However, both exercises showed positive effects.

• PNF and Movement
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• 제19권1호
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• pp.137-146
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• 2021

Purpose: The study aimed to determine the effect of proprioceptive neuromuscular facilitation (PNF) lower trapezius muscle strengthening exercise on pain, cervical range of motion (ROM), and neck disability index (NDI) in patients with chronic neck pain. Methods: Following baseline measurements, the subjects (n = 30) with chronic neck pain were randomized into two groups: the PNF group (n = 15) that received PNF strength training of the lower trapezius muscles or a control group (n = 15) that received gentle palpation of the skin. Each group participated in the intervention for 30 min, three times per week for six weeks. The visual analogue scale for pain, ROM, and NDI of both groups were recorded at both pre- and post-intervention. Paired t-tests were used to determine significant changes in the post-intervention compared with pre-intervention, and independent t-tests were used to analyze differences in the dependent variables between the two groups. Results: After the six-week intervention, both groups experienced significantly decreased pain and NDI (p < 0.05) and significantly increased cervical flexion, extension, lateral flexion, and rotation ROM (p < 0.05). The PNF group that received PNF strength exercise of the lower trapezius muscles showed greater improvements in pain and NDI and cervical rotation of ROM than those of the control group (p < 0.05). Conclusion: These results suggest that the PNF lower trapezius strengthening exercise reduces neck pain and disability level and enhances cervical ROM in patients with chronic neck pain.

• 소성∙가공
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• 제18권5호
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• pp.392-400
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• 2009

Clinching is a method of joining sheet metals together. This process can be substituted for the resistance spot welding on the joining of aluminum alloys. However, the joining strength of the clinching is lower than that of welding and riveting. The objective of this paper is to evaluate the effect of shape parameters of tools on the joining strength of the clinching and to optimize clinching tools. Twelve parameters have been selected as shape parameters on the clinching tools such as punch and die. The design of experiments (DOE) method is employed to investigate the effect of the shape parameters of tools on the joining strength of the clinching. The neck thickness and undercut of the clinched sheet metal after the clinching, and the separation load at detaching are estimated from the result of FEA using DEFORM. Optimal combination of shape parameters to maximize the joining strength of clinching is determined on the basis of the result of DOE and FEA. In order to validate the result of DOE and FEA, the experiment of clinching is performed for the optimal combination of shape parameters. It is shown from the result of the experiment that optimization of shape parameters improves the joining strength of clinching.

• 한국세라믹학회지
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• 제23권3호
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• pp.9-14
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• 1986

$\beta$-SiC bonded SiC bodies were prepared from various conditions such as several compositions of(Si+C)/$\alpha$ -SiC ratio and different firing schedules and were respectively investigated compressive strength MOR and mi-crostructure. One firing schedule which produced the specimens that had $\beta$-SiC neck form with the highest strength was selected and experimented by each firing temperature. results obtained are as follows : 1) The amount of (Si+C) for th highest MOR of SiC-(Si+C) sintered body is 20wt% 2) By adding 20wt% content of (Si+C) and heating up to 1, 500 with soaking 3hrs respectively at 1,150$^{\circ}C$ 1,250$^{\circ}C$ 1,350$^{\circ}C$ and 1,400$^{\circ}C$ the highest MOR of fired specimen was resulted and its microstructure of ma-trix was composed of close $\beta$-SiC neck. 3) Microstructure of $\beta$-SiC were different greatly from each other by firing time and/or quantity of adding mix-ture and it was confirmed that they were composed of neck particle-like and heterogeneous texture. 4)$\beta$-SiC synthesis proceed rapidly at the temperature between 1,250$^{\circ}C$ and 1,350$^{\circ}C$ 5) All of the properties of 85 SiC-20(Si+C) specimen improved according to increasing temperature above 1,350$^{\circ}C$.

• PNF and Movement
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• 제13권3호
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• pp.145-153
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• 2015

Purpose: The current study aims to identify the effects of proprioceptive neuromuscular facilitation (PNF) on pain and grip strength in patients with cervical herniated intervertebral disc (HIVD) and provide effective interventions for such patients. Methods: Included in this study were 20 subjects (10 men, 10 women) in their 30s-50s who had been diagnosed with cervical HIVD. Intervention methods included PNF neck patterns, dynamic reversal of antagonists, and a combination of isotonics. The visual analogue scale (VAS) was used to measure pain and dynamometers were used to measure grip strength. Results: After four weeks of muscle strengthening exercises, neck pain was significantly reduced, and hand grip strength significantly increased. Conclusion: PNF can be utilized as an effective intervention to reduce the pain of patients with cervical HIVD and to increase grip strength.

• 한국생산제조학회지
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• 제20권4호
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• pp.484-489
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• 2011

Nowadays, the automobile manufactures make a great efforts to reduce manufacturing cost, body weight and to develop eco-environmental parts in order to be more competitive and solve global warming. For these reasons, materials of automobile's parts are changed over from general carbon steel and stainless steel to plastic and Aluminum. And, laser welding technology is introduced to apply welding between aluminum parts. In this paper, the data of laser welding parameters is collected through lots of the experiment according to the material, welding speed and laser power to apply laser welding in Aluminum fuel filler neck assembly. After manufacturing prototype of aluminum fuel filler neck, vibration durability test, tensile strength test and salt water test are applied to verify product's satisfied function.

• 한국자동차공학회논문집
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• 제8권3호
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• pp.130-138
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• 2000

The position of the automobile seat back is very important for the neck injury in the rear-end collisions. The effects of the position have been evaluated experimentally. A sled simulator is utilized with a velocity of 33 km/h. The position is varied by the angle of seat back from 25 to 65 degrees. All the configurations of the seat are fixed except the angle. The neck injuries are calculated by the equations accepted in the industries. Also, the sled tests with other velocities are carried out for the comparison study. Using the results of the test, the effects of seat back strength are discussed to minimize the occupant neck injury in rear end collisions.

• 한국수소및신에너지학회논문집
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• 제35권2호
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• pp.195-204
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• 2024

The study involves a finite element analysis to evaluate the structural integrity of the neck mount block for a type 4 hydrogen storage vessel, with the aim of enhancing its strength and rigidity. The existing neck mount block consists of a fixed part and a sliding part, each comprising a body block for load support, a screw part for neck boss fixation, and bolts. To analyze the vulnerabilities of the neck mount block under bolt fastening and load conditions relative to vehicle travel directions, a structural analysis process was developed. Comparative analysis between the enhanced design and the existing model was performed, resulting in improved strength and rigidity. The objective is to provide guidance for the current product development and to offer fundamental data for the design and structural analysis of future development projects.