• Applied Microscopy
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• 제47권1호
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• pp.19-28
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• 2017

Since graphene was discovered in 2004, two-dimensional (2D) materials have been actively studied. Especially, 2D transition metal dichalcogenides (TMDs), such as $MoS_2$ and $WS_2$, have been the subject of significant research because of their exceptional optical, electrical, magnetic, catalytic, and morphological properties. Therefore, these materials are expected to be used in a variety of applications. Furthermore, tuning the properties of TMDs is essential to improve their performance and expand their applications. This review classifies the various doping methods of 2D TMDs, and it summarizes how the dopants interact with the materials and how the performance of the materials improves depending on the synthesis methods and the species of the dopants.

• 진공이야기
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• 제3권1호
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• pp.4-8
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• 2016

Motivated by two dimensional graphene, layered transition metal dichalcogenides (TMDs) have attracted scientific interests by their diverse electronic, optical and catalytic properties. In particular, group 6 TMDs such as $MoS_2$ and $MoTe_2$ have polymorphs (with metallic octahedral and semiconducting hexagonal phases) which are not present in graphene. Here, we introduce a new concept in 2D materials' studies, structural phase transition, with group 6 TMDs and its current research trend and applications for electric device and electrochemical catalyst.

• 대한치과의사협회지
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• 제49권2호
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• pp.72-76
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• 2011

Temporomandibular disorders refer to a large group musculoskeletal disorders that originate from the masticatory structures. The AADR recognize that temporomandibular (TMDs) encompass a group of musculoskeletal and neuromuscular conditions that involve the temporomandibular joints (TMJs), the masticatory muscles, and all associated tissues. The signs and symptoms associated with these disorders are diverse, and may include difficulties with chewing, speaking, and other orofacial functions. They also are frequently associated with acute or persistent pain, and the patients often suffer from other painful disorders. The chronic forms of TMD pain may lead to absence from or impairment of work or social interactions, resulting in an overall reduction in the quality of life. However, the consensus of recent scientific literature about currently available technological diagnostic devices for TMDs is that, except for various imaging modalities, none of them shows the sensitivity and specificity required to separate normal subjects from TMD patients or to distinguish among TMD subgroups. This article reviews the various instruments to aid in the diagnosis of TMDs, and the overall validity and practical use of the Electromyography.

• Journal of Oral Medicine and Pain
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• 제47권4호
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• pp.174-182
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• 2022

In chronic temporomandibular disorders (TMDs), constituent tissues such as muscles are sensitive to pain and psychological stress, which negatively affect the quality of life. In addition, since chronic TMDs is often accompanied by diseases such as psychological disorders and other chronic pain disorders, the diagnosis of those diseases and patient referrals are mandatory. The management of chronic pain in TMDs requires a multidisciplinary and holistic approach. Pharmacological therapy using cyclobenzaprine, serotonin and norepinephrine reuptake inhibitors, tricyclic antidepressants, progressive relaxation, and psychological approaches using cognitive behavioral therapy such as shifting negative thoughts about pain are all valid treatment options.

• Applied Microscopy
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• 제48권2호
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• pp.43-48
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• 2018

Transition metal dichalcogenide (TMD) materials have distinctive structures in comparison with other two-dimensional materials. TMD materials' structure is held together by van der Waals and covalent intralayer interactions; consequently, TMDs exhibit multiple phases and properties depending on their structure. This article reviews some of the research currently being undertaken to control TMD phases to utilize their different properties. This review introduces some trials for changing the phase of TMDs.

• 대한치과의사협회지
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• 제57권4호
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• pp.241-247
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• 2019

Etiology of temporomandibular disorders is multifactorial origin and complex. therefore, reversible and conservative treatment is recommended in the initial approach of TMD. oral appliances are widely used to manage TMDs, while their mechanisms of action and its effects remain controversial and unclear. The purpose of this paper was to review information regarding the types, designs, and materials of occlusal appliances and the rationale for the continued use of OS for the management of TMDs.

• 폴리머
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• 제32권6호
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• pp.566-572
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• 2008

메탈로센 [(TMDS)$Cp_2$]$ZrCl_2$, 촉매 1과 Exxon 촉매인 [$(n-Bu)_2Cp_2$]$ZrCl_2$, 촉매 2를 사용하여 폴리에틸렌 왁스를 제조하였다. 분자량을 조절하기 위하여 수소를 연쇄이동제로 사용하였다. 실험결과 수소의 주입량이 증가할수록 중합활성의 감소 생성된 폴리에틸렌 왁스의 분자량과 분자량 분포의 감소 그리고 폴리에틸렌 왁스의 융점 저하가 관찰되었다. 수소의 주입으로 폴리에틸렌의 분자량은 1500, 융점은 60 $^\circ$C까지 조절이 가능하였다. 수소의 양을 조절함으로써 메탈로센을 통해 분자량분포가 좁고 융점이 낮은 고품질의 폴리에틸렌 왁스의 제조가 가능하였다. 본 연구실에서 개발된 촉매 1은 알려진 가장 우수한 메탈로센인 촉매 2와 폴리에틸렌 왁스 제조에서 경쟁이 가능한 유사한 특성을 보였다.

• Smart Structures and Systems
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• 제13권2호
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• pp.257-280
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• 2014

In this paper, a novel PARAllel FACtor (PARAFAC) decomposition based Blind Source Separation (BSS) algorithm is proposed for modal identification of structures equipped with tuned mass dampers. Tuned mass dampers (TMDs) are extremely effective vibration absorbers in tall flexible structures, but prone to get de-tuned due to accidental changes in structural properties, alteration in operating conditions, and incorrect design forecasts. Presence of closely spaced modes in structures coupled with TMDs renders output-only modal identification difficult. Over the last decade, second-order BSS algorithms have shown significant promise in the area of ambient modal identification. These methods employ joint diagonalization of covariance matrices of measurements to estimate the mixing matrix (mode shape coefficients) and sources (modal responses). Recently, PARAFAC BSS model has evolved as a powerful multi-linear algebra tool for decomposing an $n^{th}$ order tensor into a number of rank-1 tensors. This method is utilized in the context of modal identification in the present study. Covariance matrices of measurements at several lags are used to form a $3^{rd}$ order tensor and then PARAFAC decomposition is employed to obtain the desired number of components, comprising of modal responses and the mixing matrix. The strong uniqueness properties of PARAFAC models enable direct source separation with fine spectral resolution even in cases where the number of sensor observations is less compared to the number of target modes, i.e., the underdetermined case. This capability is exploited to separate closely spaced modes of the TMDs using partial measurements, and subsequently to estimate modal parameters. The proposed method is validated using extensive numerical studies comprising of multi-degree-of-freedom simulation models equipped with TMDs, as well as with an experimental set-up.

• 한국치위생학회지
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• 제21권6호
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• pp.731-740
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• 2021

Objectives: The purpose of this study was to examine the effects of oral and mental health status on temporomandibular joint disorders (TMDs) and the effects of TMD symptoms on quality of life using data from the 5th 2012 National Health and Nutrition Examination Survey. Methods: A total of 1,154 people were selected as subjects for the study. Temporomandibular joint (TMJ) sounds (672 persons), TMJ pain (227 persons), and TMJ dislocation (255 persons) were the factors studied. The complex sample chi-square test was performed to compare demographic characteristics according to the three groups of TMD symptoms. Complex sample logistic regression analysis was performed to confirm the effect of oral and mental health status on TMDs, and complex sample linear regression analysis was performed to check the effect of TMDs on the quality of life (EQ-5D). Results: After adjusting for demographic characteristics, those without TMJ sound symptoms had lower pain/discomfort (OR: 0.055, CI: -0.095 to -0.016) and anxiety/depression (OR: 0.053, CI: -0.092 to -0.014). Those without TMJ pain had lower pain/discomfort (OR: 0.119, CI: -0.192 to -0.046) and anxiety/depression (OR: 0.071, CI: -0.137 to -0.004). Pain/discomfort (OR: 0.063, CI: -0.125 to -0.001) was lower in those without TMJ dislocation symptoms. After adjusting for mental health status, pain/discomfort (OR: 0.088, CI: -0.161 to -0.014) was found to be lower in those without TMJ pain symptoms (p<0.05). Conclusions: Based on the results of this study, the treatment of TMDs, oral health, and also mental health, is needed to improve the quality of life.

• Journal of Oral Medicine and Pain
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• 제41권3호
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• pp.99-109
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• 2016

Purpose: This study investigated factors influencing the xerostomia symptoms in the patients with temporomandibular disorders (TMDs). Methods: Eighty-six participants over the age of twenty were randomly enrolled from patients with TMDs. The patients were diagnosed by Diagnostic Criteria-TMD (DC-TMD). Intensity of the pain and level of stress of the patients were recorded using TMD pain visual analogue scale (VAS) and stress VAS, respectively. The Symptom Checklist-90-Revised (SCL-90R), dry mouth symptom questionnaire, unstimulated salivary flow rate (USFR) and oral moisture were measured. Results: The patients who had above the mean of the TMD pain VAS had significantly higher scores on the stress VAS, subjective dry mouth symptoms and T-score of somatization. The patients who suffered from pain more than three months had significantly higher TMD pain VAS, subjective dry mouth symptoms and T-score of somatization. There were no significant differences in xerostomic symptoms according to the diagnosis of TMDs. Moreover, TMD pain VAS and the stress VAS did not correlated to USFR and oral moisture. Conclusions: The level of individuals' TMD pain and stress significantly affect their subjective dry mouth symptoms, however, it did not affect USFR and oral moisture.