• Title/Summary/Keyword: Depth of cure

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Modification of the curing characteristics of the photocurable resin FA1260T for 3D microfabrication using microstereolithography (삼차원 마이크로광조형 기술 응용을 위한 광경화 수지 EA1260T의 경화특성 조절에 대한 연구)

  • Kim Sung-Hoon;Jung Dae-Jun;Joo Jae-Young;Jeong Sung-Ho
    • Journal of the Korean Society for Precision Engineering
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    • v.23 no.6 s.183
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    • pp.174-179
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    • 2006
  • The curing characteristics of a photocurable resin are critical factors that often decide the ultimate resolution and structural sharpness of a final product fabricated by microstereolithography$(\mu-STL)$. In this study, we investigated the curing characteristics of the FA1260T photopolymer under a visible laser light of 42nm wavelength. Modification of the curing property of the FA1260T is attempted to reduce the cure depth $(D_c)$ by adding a radical quencher to the resin. Also, an organic solvent was used to reduce the resin viscosity for an improvement of the flatness of the liquid surface during layer-by-layer curing. As a result, the minimum $D_c$ has been reduced over a factor of 3 with no abrupt increase. Samples of three dimensional microstructures fabricated using the modified FA1260T are presented.

Dental Properties of Hydroxyapatite Filled Polymer Composite (수산화인회석이 충전된 고분자 복합체의 치과적 물성)

  • Kim Oh-Young;Seo Ki-Taek
    • Polymer(Korea)
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    • v.30 no.2
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    • pp.135-139
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    • 2006
  • To evaluate the dental restorative application of polymer composites filled with hydroxyapatite (HAP) which is an inorganic component of human bone material, dental properties of the polymer composites were investigated. A visible light system was utilized to activate the acrylate resin matrix of the composites. Maximum loading percentage of HAP in composite was 65 wt% and the depth of cure was 6.0 mm which can be applicable for dental restoration. With increasing the HAP content, degree of conversion of polymer composites was slightly decreased, however, polymerization shrinkage value was not varied. Diametral tensile strength value was enhanced with an increase of HAP content, however, there was no strict trend between flexural strength and HAP concentration. Anyhow, polymer composites prepared herein have superior mechanical properties sufficient specifications applicable to dental materials.

Research Trends on Qigong in the Korean Journal (한국 저널에 게재된 기공관련 단일군 임상연구 동향 분석)

  • Park, Sun-Hee;Han, Chang-Hyun;Kim, Ki-Jin;Shin, Mi-Suk;Choi, Sun-Mi
    • Korean Journal of Oriental Medicine
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    • v.14 no.2
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    • pp.75-80
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    • 2008
  • Background: Qigong is one energy-healing intervention used to prevent and cure ailments and to improve health through regular practice. Although Qigong-neither itself nor its postulated mechanism of action-are within the paradigm of modern Western medical science. effects on the human body could be possible. Objectives: This study aims to review the bibliography, biological responses and therapeutic effects of Qigong. In the process, this review grasp trends in this field of studies and direct further researches into the right direction. Method: The computerized Korean databases were searched from their respective inception up to January 2008. The search terms used were 'Qi', 'Qigong', 'Doin', 'training', 'bioenergy', 'life nurturing' and random or Korean language terms related to qigong. Several specialized journals were also manually searched for relevant articles. Result: Since the 1990s, Qigong papers in the Korean Literature have been increased. Clinical research studies are among the most control design study. Research subjects are less patient than the general public. The most common treatment disease was Musculo-skeletal disorder. Conclusions: The depth study for the each Qigong is needed. Specifically, I think it should be a clinical studies and qualified research methods for evaluation are needed.

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INFLUENCE OF CAVITY SIZE AND RESTORATION METHODS ON THE CUSP DEFLECTION IN COMPOSITE RESTORATION (복합레진 수복시 와동의 크기 및 수복 방법이 교두 굴곡에 미치는 영향)

  • Lee Mi-Ra;Lee In-Bog;Seok Chang-In;Lee Sang-Tag;Um Chung-Moon
    • Restorative Dentistry and Endodontics
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    • v.29 no.6
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    • pp.532-540
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    • 2004
  • The aim of this study was to measure the cusp deflection during composite restoration for MOD cavity in premolar and to examine the influence of cavity dimension, C-factor and restoration method on the cusp deflection. Thirty extracted maxillary premolar were prepared to four different sizes of MOD cavity and divided into six groups. The width and depth of the cavity were as follows. Group 1; $1.5{\;}{\times}{\;}1{\;}mm$, Group 2; $1.5{\;}{\times}{\;}2{\;}mm$, Group 3; $3{\;}{\times}{\;}1{\;}mm$, and Group 4-6; $3{\;}{\times}{\;}2{\;}mm$ respectively. Group 1-4 were restored using bulk filling method with Z-250 composite. However, Group 5 was restored incrementally, and Group 6 was restored with an indirect resin inlay. The cusp deflection was recorded at the buccal and lingual cusp tips using LVDT probe for 10,000 seconds. The measured cusp deflections were compared between groups, and the relationship between the cube of the length of cavity wall/the cube of the thickness of cavity wall ($L^3/T^3$). C-factor and cusp deflection or % flexure ($100{\;}{\times}$ cuspal deflection / cavity width) was analyzed. The cusp deflection of Group 1-4 were $12.1{\;}\mu\textrm{m},{\;}17.2{\;}\mu\textrm{m},{\;}16.2{\;}\mu\textrm{m}{\;}and{\;}26.4{\;}\mu\textrm{m}$ respectively. The C-factor was related to the % flexure rather than the cusp deflection. There was a strong positive correlationship between the $L^3/T^3$ and the cusp deflection. The cusp deflection of Group 5 and 6 were $17.4{\;}\mu\textrm{m}{\;}and{\;}17.9{\;}\mu\textrm{m}$ respectively, which are much lower value than that of Group 4.

Comparison of Microleakage and Compressive Strength of Different Base Materials (여러 치과 와동 기저재용 재료들의 미세누출 및 압축강도 비교)

  • Jang, Eunyeong;Lee, Jaesik;Nam, Soonhyeun;Kwon, Taeyub;Kim, Hyunjung
    • Journal of the korean academy of Pediatric Dentistry
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    • v.48 no.2
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    • pp.168-175
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    • 2021
  • This study compared the microleakages and compressive strengths of various base materials. To evaluate microleakages, 50 extracted permanent premolars were prepared. The teeth divided into 5 groups of 10 each according to the base materials. Cavities with a 5.0 mm width, 3.0 mm length, and 3.0 mm depth were formed on the buccal surfaces of the teeth. After filling the cavities with different base materials, a composite resin was used for final restoration. Each specimen was immersed in 2% methylene blue solution and then observed under a stereoscopic microscope (× 30). To evaluate the compressive strength, 5 cylindrical specimens were prepared for each base material. A universal testing machine was used to measure the compressive strength. The microleakage was highest in the Riva light cureTM group and lowest in the BiodentineTM and Well-RootTM PT groups. For the compressive strengths, in all groups, acceptable strength values for base materials were found. The highest compressive strength was observed in the Fuji II LCTM group and the lowest strength in the Well-RootTM PT group.

Clinical Report of One Chronic Several Patient on the Cancer of the Prostate Gland by Using BUDDEUMI;equipment with using Combination of Moxibustion and Cupping Literatures (부뜸이에 의한 전립선암 치료 1례 보고)

  • Kim, Gyeong-Cheol;Yang, Han-Joe
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.21 no.6
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    • pp.1660-1662
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    • 2007
  • "BUDDEUMI is a new remedy of the synchronous combination of cupping boil and moxibustion for the exclusion of human body's waste product. It wishes the reach for improving the effect of cupping boil and moxibustion by the synchronous combination. As the negative pressure of cupping and the hot cure of moxa are made up of BUDDEUMI structural character. In order to determine the depth-hot effect of BUDDEUMI, clinical study was performed in the cancer of the prostate gland for several years. The targets of study was one person with the cancer of the prostate gland for several years. The BUDDEUMI was operated 3-4 times/ day, during 12 months on the Gowan-Won, Jang-Wan, Jeon Jung and the abdominal region & Jang-Gang, Meong-Moon, Dae-Chue and the back region. Therefore we compared PSA(prostate singular antigen: June, 2006/ June, 2007) before and after BUDDEUMI therapy. PSA significantly decreased in a comparison of before-treatment (30.76) and after 12 months (0.76). And the times of enuresis significantly decreased in a comparison of before-treatment (5-10 times) and after 12 months(1-2 times). The effects of BUDDEUMI are observed on the treatment of the cancer of the prostate gland. As "BUDDEUMI and BUDDEUMI's treatment" is expected to relieve pain, and for the healthy article of Senior-Friendly.

Troilus and Criseyde: Desire and Death (『트로일러스와 크리세이다』 -욕망과 죽음)

  • Lee, Dongchoon
    • Journal of English Language & Literature
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    • v.56 no.4
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    • pp.691-717
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    • 2010
  • Chaucer's Troilus and Criseyde is a tale of love framed by an overarching pattern of death, set in the war-torn and doomed Troy, from which the lovers cannot separate their fate. Compared with Boccaccio's poem, the attention paid to death in Chaucer's version underlies his complex treatment of love. Above all, the language of death in Chaucer's poem provides the thread from which the entangled web of love is woven. Death together with desire pervades the language and rhetoric of the poem, prominent not only in the courtly love tropes, but also in the characters' asides and speeches. The prominence of these two concepts, desire and death, seem to be central to the various issues that the poem contains explicitly and implicitly. That is, two concepts are the basis for the breadth and depth of Chaucer's examination of love in light of the social and political realities of late fourteenth century England. The language of death in Chaucer's poem reflects the powerful influence on his imagination. With the devastation wrought by the plague and the changing fortunes of England in the war with France, Chaucer's world was once saturated in death, and one that could amply parallel the turn from prosperity to downfall. In particular, Chaucer's poem is suffused with the language of contagion and death in connection with desire. Troilus's lovesickness mimics the progress of a viral infection. Once breached, his body performs its newly compromised identity through fever, loss of appetite, and physical disintegration. On the other hand, Chaucer depicts Boccaccio's conventional portrait of Criseyde into a elaborate paramour of a pathogen. She is characterized as the contaminant that infects male hero. In addition, Criseyde is cast as sole earthly cure of illness that Troilus suffers from. In spite of Criseyde's role as nurturer and healer, Troilus longs for his own death and feels death clutching his heart. Finally, Troilus's love toward Criseyde is doomed to death.

COMPENSATION EFFECT OF EXPOSURE TIME INCREASE TO DECREASED LIGHT INTENSITY OF VISIBLE-LIGHT CURING UNIT (가시광선 중합기의 조사강도 감소에 대한 조사시간 증가의 보상효과)

  • Yoon, Tae-Won;Lee, Chang-Seop;Lee, Sang-Ho
    • Journal of the korean academy of Pediatric Dentistry
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    • v.24 no.1
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    • pp.325-336
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    • 1997
  • The purpose of this study was to evaluate the compensation effect of exposure duration increase to decreased light intensity of visible-light curing unit. The specimen with 2mm thickness was made of Restorative $Z-100^{TM}$ (A2 shade, 3M Dental Products, U.S.A.) and cured with $Optilux^{TM}$ (Demetron Research Co. U.S.A.). The light intensity was controlled to 420 $mW/cm^2$, 540 $mW/cm^2$, 630 $mW/cm^2$ and curing time, also, controlled to 40, 60, 80 seconds. Cured specimen was stored in a light-proof container for 24 hours to post-irradation was completed. Microhardness of top and bottom surface of specimen were measured to evaluate the depth of cure. The obtained results were as follows: 1. The microhardness of top and bottom surface of the composite resin specimen was increased significantly as light intensity and exposure time was increased (P<0.01). 2. Light intensity was more correlated with bottom microhardness(${\gamma}{\geq}$0.438) than top microhardness(${\gamma}{\geq}$0.213), and exposure time was more correlated with top microhardness (${\gamma}{\geq}$0.424) than bottom microhardness(${\gamma}{\geq}$0.335). 3. The regressive equation was obtained in this study as follows : $H=0.07{\times}D+0.012{\times}I+76$ (H : Microhardness(KHN), D : Exposure time, I : Light intensity)

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Research Trends on Qigong in the Korean Journal (한국 저널에 게재된 기공관련 연구 동향 분석)

  • Han, Chang-Hyun;Lee, Sang-Nam;Kwon, Young-Kyu;Choi, Sun-Mi
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.22 no.4
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    • pp.954-959
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    • 2008
  • Qigong is one energy-healing intervention used to prevent and cure ailments and to improve health through regular practice. Although qigong-neither itself nor its postulated mechanism of action - are within the paradigm of modern Western medical science, effects on the human body could be possible. This study aims to review the bibliography, biological responses and therapeutic effects of Qigong. In the process, this review will grasp trends in this field of studies and will direct further researches into the right direction. The computerized Korean databases were searched from their respective inceptions up to January 2008. The search terms used were 'qi', 'qigong', 'doin', 'training', 'bioenergy', 'life nurturing' and random or Korean language terms related to qigong. Several specialized journals were also manually searched for relevant articles. Since the 1990s, Qigong papers in the Korean Literature is increased. Published 152 papers on Korean medicine were more than Physical education and Nursing. 78 papers published in The Journal of Korean Academy of medical Gi-gong are the best in many areas related to Korean medicine. Most people have submitted papers related to Qigong was Lee Gi-nam. The depth study for the each Qigong is needed. Specifically, I think it should be a clinical studies and qualitative research methods for evaluation are needed.

Research clinical trends on Gigong(氣功, Qigong) in the Korean Journal (한국(韓國) 저널에 게재(揭載)된 기공관련(氣功關聯) 임상(臨床) 연구(硏究) 동향(動向) 분석(分析) )

  • Han, Chang-Hyun;Lee, Sang-Nam;Kwon, Young-Kyu;Ahn, Sang-Woo;Choi, Sun-Mi
    • Journal of Korean Medical classics
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    • v.21 no.3
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    • pp.297-306
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    • 2008
  • Background : Gigong(氣功, Qigong) is one energy-healing intervention used to prevent and cure ailments and to improve health through regular practice. Although Gigong(氣功, Qigong) - neither itself nor its postulated mechanism of action - are within the paradigm of modern Western medical science, effects on the human body could be possible. Objectives : This study aims to review the bibliography, biological responses and therapeutic effects of Gigong. In the process, this review will grasp trends in this field of studies and will direct further researches into the right direction. Method : The computerized Korean databases were searched from their respective inceptions up to January 2008. The search terms used were 'Gi(氣, Qi)', 'Gigong(氣功, Qigong)', 'Doin(導引)', 'Training', 'Bioenergy', 'life nurturing' and random or Korean language terms related to Gigong. Several specialized journals were also manually searched for relevant articles. Result : Since the 1990's, Gigong papers in the Korean Literature is increased. Clinical research studies are among the most control design study. Research subjects are less patient than the general public. The most common treatment disease was Musculo-skeletal disorder Conclusions : The depth study for the each Gigong(氣功, Qigong) is needed. Specifically, I think it should be a clinical studies and qualitative research methods for evaluation are needed.

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