• Journal of Adhesion and Interface
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• v.24 no.2
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• pp.41-53
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• 2023

The deformable devices refer to the devices that can maintain their initial performance even when stretched or bent. Among the materials used as conductor in deformable devices, Ga-based liquid metal is one of the most promising materials because it can provide not only high conductivity and deformability but also low toxicity. In this paper, we introduce Ga-based liquid metals and then discuss the recent research trend in deformable devices composed of Ga-based liquid metal.

• Journal of the Korean Society of Visualization
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• v.21 no.2
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• pp.24-33
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• 2023

This work is to observe the wake flow generated behind a ramp. We have conducted a large eddy simulation with two ramp models having different heights with two different inflow conditions. Reynolds number based on the height of the large ramp (LR) and small ramp (SR) are Re_h = 2.8×10⁴ and 1.4×10⁴ respectively. The wake flow visualization shows the formation of streamwise counter-rotating vortices pairs at the downstream of the obstacle. These primary vortices are stretched and lifted up when moving downstream. In order to observe the effect of the inflow condition on the wake transition, two different inlet flow conditions are given on the inlet section as an inlet boundary condition. Induced counter-rotating vortices pairs due to sharp-edged triangular ramp obstacles are developed and propagated downstream. In the result, the large ramp shows a more complicated wake structure of the boundary layer than the small ramp.

• SUVANNABHUMI
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• v.9 no.1
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• pp.109-132
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• 2017

This article is about the emergence of Islamic modernism among Cham Muslim communities in Cambodia and Cochinchina during the early 20th century. Based on a combined critical reading of existing scholarship, historicized first-hand anthropological accounts, as well as archival sources from the National Archives of Cambodia and the Vietnam National Archives II, it argues accounts of modernists in these sources were either (1) cast through a French colonial reading of a Buddhist state lens and (2) cast through a Malay lens, based upon the Kaum Muda/Kaum Tua divide. First, it proceeds with a historical explanation of the emergence of Islam and the discourse used to describe Muslim communities in Vietnamese, French, and Cham language sources. Then, it turns the narrative toward an examination of the emergence of the "Kaum Muda" or "New Group" of reformist-minded modernist Muslims in early 20th century Cambodia. Delineating the networks of these intellectuals as they stretched across the border through Cochinchina, also highlights a pre-existing transnational element to the community, one that well predates current discussions of twenty-first-century transnationalism. Through a combination of the study of multiple language sources and historical methods, the article highlights the importance of polylingualism in the study of the history of Muslims in Southeast Asia.

• Textile Coloration and Finishing
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• v.35 no.4
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• pp.231-238
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• 2023

Microporous gel films of 29 m were prepared by the gel drawing of UHMWPE/soybean oil blend (4:6, w/w) up to 800%. The stretched films containing the optimal photoinitiator concentration, depending on the film thickness, was cross-linked under 365 nm LED-UV irradiation and the oil was extracted with n-hexane, resulting in a gel fraction of 95 % or more. With the formation of the cross-linked structure, the melt-down temperature and melt-down elongation increased by 16 ℃ and by 63% respectively. Also the thermal stability of the crosslinked UHMWPE was proved by the area shrinkage under the heat treatment decreased to 3.8 % compared to 17.4 % for the pristine film, and by the reductions in the combustion heat. The enhanced thermal stability of the crosslinked UHMWPE microporous membranes can be used for various industrial applications such as filters, electric vehicles and energy storage systems.

• Korean Journal of Applied Biomechanics
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• v.33 no.4
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• pp.137-146
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• 2023

Objective: The horizontal bar of gymnastics is fundamentally based on rotational movements. This study aimed to determine the effect of kinematics variables and sequence during horizontal bar performance (Kovacs, Tkatchev Stretched & Kolman) in gymnastic. Method: Four gymnastics athletes of the national team were participated in this study. All subjects were asked to perform the three types of horizontal bar skill. Simi marker-less cameras were used to collect the raw data (120 Hz). Kinematic variables (total time, interval, center of mass, height, angular velocity etc.) and sequence variables were calculated to examine the differences. Results: As a result, horizontal bar performance in gymnastic has special sequence that making the peak angular velocity from distal joint to proximal joint (knee-hip-shoulder). It is rare sequence that typical sport does not have. Conclusion: In field, gymnastic coaches and players should know the result that there is special sequence in horizontal bar performance. It could be very useful to teach and enhance their performance.

• Journal of the Korean Electrochemical Society
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• v.11 no.3
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• pp.190-196
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• 2008

The multilayered membrane for lithium rechargeable batteries based on poly (vinylidene fluoride) (PVdF) is prepared with the coated layer containing nano-sized filler. The prepared membranes were subjected to studies of mechanical strength, morphology, interfacial stability, impedance spectroscopy, ionic conductivity, and cycle performance. The localized inorganic filler in the PVdF composite membrane rendered mechanical strength much reduced because of its low stretching ratio and it results in around half value of the mechanical strength of highly stretched PVdF membrane. In order to achieve high ionic conductivity and interfacial stability without sacrificing high mechanical strength, coating layer with nano-filler was newly introduced to PVdF membrane. The ionic conductivity of the coated membrane was 1.03 mS/cm, and the interface between the coating layer and PVdF membrane was stable when the membrane was immersed into liquid electrolyte. The discharge capacity of the cell based on nano-filler coated PVdF membrane was around 91% of the initial discharge capacity after 250 cycles, which is an improvement in cycle performance compared to the case for the non-coated PVdF membrane.

• The Korean Journal of Pain
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• v.25 no.3
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• pp.161-167
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• 2012

Background: Neck and shoulder pain (NSP) is fairly common in adolescents, which is associated with a high prevalence of NSP found during adulthood as well; therefore, its significance during adolescence should not be underestimated. We surveyed the prevalence of recurrent NSP, lifestyle, and risk factors in Korean high school students, and examined the influence of recurrent NSP on the quality of life. Methods: Nine hundred thirty one male students (16-19 years old) from two academic high schools in Seoul were included in this study. The survey consisted of a questionnaire to assess the prevalence of recurrent NSP, with questions regarding having an occurrence more than once a week, characteristics of NSP, activity and lifestyle of the students, and the risk factors for recurrent NSP. A 36-item Short Form questionnaire was also examined. Results: We found that 44.3% of the high school students surveyed had recurrent NSP (more than once a week) and the overall prevalence of NSP was 79.1%. The average sitting time was $10.2{\pm}2.7$ h/day. 59.0% did not sit straight, 14.7% used assisting devices during reading, and 11.9% answered that they stretched regularly. Found from their self assessed health, frequent fatigue and frequent depressed mood presented significant associations with the higher prevalence of recurrent NSP. Conclusions: Korean high school students had a high prevalence of recurrent NSP. Clinical attention is needed for the prevention and resolution of recurrent NSP found in high school students.

• Polymer(Korea)
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• v.39 no.3
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• pp.370-381
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• 2015

In the system of poly(vinyl alcohol) (PVA)/dimethyl sulfoxide, the refractive index of polymer was very well matched to that of solvent and thus its scattered intensity could be minimized. After adding small amount of polystyrene latex particle (nominal diameter 200 nm), diffusion behavior of only probe particle was investigated against the concentration of polymer matrix by means of dynamic light scattering. The polymer concentration dependence of its reduced diffusion coefficient was able to be analysed with the stretched exponential function of the reduced concentration $C[{\eta}]$. In very dilute concentration regime, the depletion layer kept constant but at the early semi-dilute regime of $1{\leq}C[{\eta}]{\leq}2.5$, the concentration-dependent exponent of depletion layer ${\delta}$ was appeared to be -0.8 which was very close to theoretical one of -0.85. However it was also observed at the higher concentration that its layer thickness decreased more abruptly than theoretical expectation and this phenomenon was ascribed to Oosawa type attractive interaction between adjacent latex particles.

• Journal of the Korean Arthroscopy Society
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• v.12 no.2
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• pp.134-138
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• 2008

SLAP(Superior labrum anterior to posterior) lesion is found in superior labrum injury alone and also combined with extension of the Bankart lesion(anteroinferior labral tear) in recurrent shoulder dislocation patients and rarely accompanied by the posterior Bankart lesion. There have been reports about SLAP lesions associated with various lesions, however, posterior type II SLAP lesion associated with posterior Bankart lesion has been rarely reported. In such a case, there are important technical tips in inserting anchors and suturing during arthroscopic repair. We experienced a rare case of posterior type II SLAP lesion associated with posterior Bankart lesion, occurred not after repetitive throwing(common mechanism) but after trauma in slipping down with the arm stretched during riding a bicycle. The satisfactory result was obtained after arthroscopic repair in this case.

• The Research Journal of the Costume Culture
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• v.24 no.3
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• pp.358-366
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• 2016

This study was performed to measure the posture correction effect of wearing ergonomic experimental clothing. Two types of experimental clothing (A, B) were developed. Both of them reinforced the muscles surrounding the spine. Experimental clothing A was developed by reflecting the shape and position of the pectoralis major muscle, abdominal muscle, and latissimus dorsi muscle. Experiment clothing B was developed by reflecting the integrated form of those muscles. Subjects were males in their 20s~30s (n=32). They were divided into two groups based on their acromion distance (AD): the turtle neck syndrome group (n=16, AD=3.81cm) and the normal group (n=16, AD=1.27cm). The correction of body posture was detected by three index values: change of the cervical curvature angle, horizontal distance between the seventh cervical vertebra and tragion, and AD. The comfort and tightness of the clothing were also measured. The results showed that both types of experimental clothing corrected body posture and that turtle neck syndrome can be prevented by wearing these types of posture correcting clothing. Two index values were decreased: cervical curvature angle ($0.31{\sim}1.32^{\circ}$) and horizontal distance between seventh cervical vertebra and tragion (0.22~0.31cm). The chest was also stretched. The comfort was rated as good for both types of experimental clothing. These results indicate that the experimental clothing had a posture correction effect without any discomfort for daily living.