• 제목/요약/키워드: hybrid materials

검색결과 1,856건 처리시간 0.028초

강화형 치관용 복합레진의 인장강도에 관한 연구 (A STUDY ON THE TENSILE STRENGTH OF REINFORCED VENEERING COMPOSITE RESINS FOR CROWN)

  • 안승근;강동완
    • 대한치과보철학회지
    • /
    • 제38권2호
    • /
    • pp.226-241
    • /
    • 2000
  • Recently a new generation of crown and bridge veneering resins containing submicron glass fillers was introduced. These ultrasmall particle hybrid composite materials distinguish themselves, compared with conventional microfill crown and bridge resins, through improved mechanical properties. It is claimed that these composites are suitable for metal free crowns and even bridges using fiber reinforcement. The purpose of this study was to evaluate the effect of thermal cycling on the tensile strength of the following veneering composites: Artglass(Heraeus Kulzer Co., Wehrheim, Germany), Estonia(Kuraray Co.. Japan), Sculpture(Jeneric Pentron Co., Wallingford, U.S.A.), and Targis(Ivoclar Co., Schaan Liechenstein). According to manufacturer's instructions, rectangular tensile test specimens measuring $1.5{\times}2.0{\times}4.5mm$ were made using a teflon mold. Whole specimens were divided into two groups. One group was dried in a desiccator at $25^{\circ}C$ for 10 days, and another group was subjected to thermal cycling($10,000{\times}$) in water($5/55^{\circ}C$). All test specimens were placed in a universal testing machine and loaded until fracture with a crosshead speed of 0.5mm/min. Weibull analysis and Tukey's test were used to analyze the data. The fracture surfaces of specimens were observed in SEM and the aliphatic C=C absorbance peak of Estenia and Targis resin was analyzed using Fourier transform infrared(FTIR) spectroscopy. Within the limitations imposed in this study, the following conclusions can be drawn: 1. Both in drying condition and thermal cycling condition, the highest tensile strength was observed in Estenia testing group(p<0.05). 2. The strength data were at to single-mode Weibull distribution, and the Weibull modulus of all veneering composite resin specimens increased after thermal cycling treatment. 3. After thermal cycling test, the highest tensile strength was observed in the Estenia group, and the lowest value was observed in the Targis group. The tensile strength values showed the significant differences between each group(p<0.05) 4. The aliphatic C=C absorbance peak of Estonia and Targis resin was decreased after light curing, and there was no distinct change after thermal cycling.

  • PDF

간호서비스 마케팅에 관한 연구;'촉진(Promotion)' 개념 개발 (Concept Development of Service Marketing Promotion in Nursing)

  • 강윤숙
    • 간호행정학회지
    • /
    • 제5권1호
    • /
    • pp.63-76
    • /
    • 1999
  • The main objective of this study was to develop a concept of service marketing promotion in nursing that is derived from the concepts of service marketing theory. This research was a descriptive study, at the factor isolation level. The principle of concept derivation suggested by Walker and Avant (1988) and the Hybrid model suggested by Schwarz-Barcott and Kim (1993) were employed as the research method. The data were collected from December, 1997 to April. 1998 at a large general hospital located in Seoul. The procedures of this study were as follows: First. at the theoretical phase: the meaning, attributes, and definition of service marketing promotion were identified through an extensive review of the literature. Second, at the empirical phase: fieldwork was done to identify the promotional activities and events in nursing. Top nurse managers from 4 units (Director of Nursing, Head nurses of inpatient nursing unit, outpatient nursing unit. and home care nursing unit) were interviewed and the content of the interview was analyzed to identify the meaning and attributes of promotion in nursing. Other methods such as brochures and other audio-visual materials which were relevant to nursing promotion were used to supplement the interviews. Finally, the results of the theoretical and empirical analyses were intergrated to develop a concept of service marketing in nursing practice. A final definition of service marketing promotion in nursing was identified as follows. 1. Promotion as a marketing function in nursing service is concerned with communication to target markets on all information related to nursing service in order to satisfy the objectives of both a nursing service organization and the target markets. 2. The goals of nursing service promotion include: 1) increasing visibility of nursing services and delivering the information on nursing services, 2) affirming the value of nursing services, so it can contribute to formulation of reimbursement policy for nursing services. 3) advancing the general image of the nursing profession and nursing services. 4) achieving and attaining a desirable positioning for nurses among health care professionals. and 5) creating and stimulating the demand for nursing services. 3. In order to obtain these goals it is necessary to provide information on nursing services, to persuade target markets. to remind them about nursing services. and to establish a collaborative relationship with related departments. 4. The tools used to carry out the above functions of promotion in nursing are the providing nursing services, public relations and publicity. QA of nursing, advertising, and sales promotion. 5. The target markets of nursing service include the nursing customer markets. the internal markets, the influence markets. the recruitment markets. the supplier markets. and the nursing referral markets. In conclusion, the concept of promotion in other service marketing areas can be applied to the promotion of nursing service marketing. The promotion of nursing service is more than just effective communication in nursing service. it is the effective use of the concepts of service marketing promotion. Promotion of nursing service will contribute to create and expand nursing services.

  • PDF

섬유 조합변화가 HPFRCC의 공학적 특성에 미치는 영향 (Effect of Hybrid Fibers on the Engineering Properties of HPFRCC)

  • 한동엽;한민철;강병희;박용준
    • 한국건축시공학회지
    • /
    • 제14권6호
    • /
    • pp.639-645
    • /
    • 2014
  • 최근에는 현대사회의 기술발전으로 인간의 삶의 질이 향상됨에 따라 건설산업에서도 재료 및 건축구조물의 발전이 계속되고 있는데, 그 중에서 콘크리트 재료의 발전이 특히 주목받고 있다. 그러나, 콘크리트는 간편성, 공기단축 및 높은 압축강도 등의 이점이 있는 반면에, 낮은 인장 및 휨강도, 취성파괴 및 건조수축 등의 문제점들이 발생하여 일부 기업 및 학계에서는 이를 해결하기 위하여 섬유보강 콘크리트 등 다방면의 연구가 진행되고 있다. 그 중, 섬유의 다량혼입으로 큰 응력에서 넓은 범위의 변형을 일으킬 수 있는 HPFRCC 재료 개발의 경우 섬유의 다량 혼입으로 높은 인성 등 발휘하는 장점이 있으나, 섬유 뭉침 등의 문제로 유동성 저하의 문제점이 발생하여 궁극적으로는 콘크리트의 품질저하를 초래할 수 있다. 따라서 본 연구에서는 인장 및 휨 강도 성능 향상을 확보를 위해 섬유를 활용한 섬유보강 HPFRCC의 시멘트 복합재료에 시공성능을 향상시키기 위한 목적으로 유 무기 섬유 조합변화에 따른 HPFRCC의 유동 특성 및 역학적 특성 등을 분석하므로서 최적의 섬유조합을 제안하고자 한다. 결과적으로 1 % 소량 혼입시 유동성 측면에서는 섬유 조합변화한 경우보다 단독으로 사용하였을 경우 높은 유동성을 나타내었고 특히, SS섬유의 경우가 가장 높은 유동성을 나타내었다. 또한 공기량이 낮았던 유기섬유의 경우 상대적으로 공기량이 높았던 강섬유의 비해 강도는 높았지만 인장 및 휨 강도는 낮은 것으로 나타났다.

섬유금속적층판의 모드 I 접합 거동 예측을 위한 Levenberg-Marquardt 기법 기반의 역해석 기법에 관한 수치적 연구 (Numerical Study on Inverse Analysis Based on Levenberg-Marquardt Method to Predict Mode-I Adhesive Behavior of Fiber Metal Laminate)

  • 박으뜸;이영헌;김정;강범수;송우진
    • Composites Research
    • /
    • 제31권5호
    • /
    • pp.177-185
    • /
    • 2018
  • 섬유금속적층판은 금속과 섬유 강화 복합소재를 함께 적층한 하이브리드 재료 중 하나다. 섬유금속적층판은 계면의 접착층이 파괴되는 층간분리 현상이 발생할 수 있기 때문에 계면의 접착층에 대한 한계응력과 에너지 해방률을 실험적으로 도출해야만 한다. 하지만, 온도에 따른 에너지 해방률을 실험적으로 도출하는 과정에서 측정 장비의 사용 온도에 대한 제약을 받는다. 따라서, 본 연구에서는 Levenberg-Marquardt 기법을 기반한 역해석 기법을 사용하여 접착층에 대한 모드 I 한계응력과 에너지 해방률에 대한 예측 가능성을 확인하는 것이 목표다. 먼저, 한계응력은 접착층의 인장강도와 같다고 가정하였으며, 에너지 해방률은 DCB 시험(double cantilever beam test)을 수행하여 정의하였다. 또한, 유한요소법 기반 모델을 적용하여 한계응력과 에너지 해방률을 수치해석적으로 예측할 수 있는 지 확인하였다. 그 후, Levenberg-Marquardt 기법을 유한요소법 기반 모델에 적용하여 모드 I 한계응력과 에너지 해방률을 수치해석적으로 예측하였다. 아울러, 본 연구에서 사용한 역해석 기법의 수렴성을 확보하기 위하여 두 가지 경우의 초기 매개변수에 대한 역해석을 추가적으로 수행하였다. 결과적으로, 본 연구에서 사용한 역해석 기법은 모드 I 한계응력과 에너지 해방률을 효과적으로 예측할 수 있음을 보였다.

생쥐배아의 동결보존에 관한 실험적 연구 (The Experimental Study on Cryopreservation of Mouse Embryo)

  • 이여일;권영숙;박현정
    • Clinical and Experimental Reproductive Medicine
    • /
    • 제28권1호
    • /
    • pp.55-63
    • /
    • 2001
  • Objectives: This study was carried out to evaluate the effects of embryonic stage, cryoprotectant, and freezing-thawing method on the rates of survival and development of the cryopreserved mouse early embryo and finally to establish the cryopreservation method of surplus embryos obtained during assisted reproductive technology (ART). Materials and Methods: Two to eight cell embryos were obtained from oviducts of mated $F_1$ hybrid female mice superovulated by pregnant mare's serum gonadotropin (PMSG) and human chorionic gonadotropin (hCG). Two-step 1,2-propanediol (PROH), dimethylsulfoxide (DMSO) and 4-step PROH DMSO were used as cryoprotectant and dehydration and rehydration method of embryos, and slow-cooling or rapid-cooling method was used as frozen program. The survival rates of embryos were measured after thawing and rehydration, and the developmental rates of embryos were compared and observed during culturing embryos for 24, 48, 72, 96 hrs. Results: As for the survival and development rates of embryos according to embryonic stage, the survival rate of 2 cell stage in PROH and DMSO was significantly higher than 4-8 cell (64.5% versus 62.1 %,79.7% versus 73.2%) (p<0.01, p<0.01), but the development rates of 4-8 cell embryos in PROH and DMSO were significantly higher than 2 cell embryos for whole culture period (p<0.01) and the development rates of 4-8 cell embryos in PROH were significantly higher than 2 cell embryos in DMSO (p<0.01). As for the survival and development rates of embryos according to cryoprotectant, the survival rate of 2 cell embryo in DMSO was significantly higher than that in PROH (74.4% versus 64.5%) (p<0.01), whereas the development rate of embryos was not differ till 24 hrs. The developmen1 rate from morular to hatching blastocyst, however, was significantly higher in PROH than in DMSO during 48 hr (p<0.01). The survival rate of 4-8 cell embryo was 62.1% in PROH and 73.2% in DMSO. The development rates of embryo in PROH were significantly higher for whole culture periods (p<0.01, 0.05). In respect to the effect of freezing and thawing program on the survival and development rates of embryos, method of slow cooling and rapid thawing was more effective than that of rapid cooling and rapid thawing. Conclusions: The survival rate of embryo in 2 cell stage was higher than in 4-8 cell stage, and PROH appears more effective cryoprotectant than DMSO because PROH showed better development rates of embryos in 2 and 4-8 cell stage. Moreover, slow cooling and rapid thawing method was considered as the best cryopreservation program.

  • PDF

Application of HPV DNA Testing in Follow-up after Loop Electrosurgical Excision Procedures in Northern Thailand

  • Khunamornpong, Surapan;Settakorn, Jongkolnee;Sukpan, Kornkanok;Kietpeerakool, Chumnan;Tantipalakorn, Charuwan;Suprasert, Prapaporn;Siriaunkgul, Sumalee
    • Asian Pacific Journal of Cancer Prevention
    • /
    • 제16권14호
    • /
    • pp.6093-6097
    • /
    • 2015
  • Background: HPV DNA testing has been recently introduced as an adjunct test to cytology in the follow-up of patients after treatment for cervical lesions using the loop electrosurgical excision procedure (LEEP). The aim of this study was to evaluate the role of HPV testing in the detection of persistent or recurrent disease after LEEP in patients with cervical epithelial lesions in northern Thailand. Materials and Methods: Patients who underwent LEEP as a treatment for histological low-grade (LSIL) or high-grade squamous intraepithelial lesion (HSIL) or worse at Chiang Mai University Hospital between June 2010 and May 2012 were included. Follow-ups were scheduled at 6-month intervals and continued for 2 years using co-testing (liquid-based cytology and Hybrid Capture 2 [HC2]) at 6 months and 24 months and liquid-based cytology alone at 12 and 18 months. Results: Of 98 patients included, the histological diagnoses for LEEP included LSIL in 16 patients, and HSIL or worse in 82 patients. The LEEP margin status was negative in 84 patients (85.7%). At follow-up, 10 patients (10.2%) had persistent/recurrent lesions; 4 among LSIL patients (25.0%) and 6 in the group with HSIL or worse (7.3%). Only 2 of 82 patients (2.4%) with HSIL or worse diagnoses had histological HSIL in the persistent/recurrent lesions. Using histologically confirmed LSIL as the threshold for the detection of persistent/recurrent disease, cytology had a higher sensitivity than HC2 (90.0% versus 70.0%). At the 6-month follow-up appointment, combined cytology and HC2 (co-testing) had a higher sensitivity in predicting persistent/recurrent disease (80.0%) compared with that of cytology alone (70.0%) and HC2 (50.0%). Conclusions: After LEEP with a negative surgical margin, the rate of persistent/recurrent lesions is low. The addition of HPV testing at the 6-month visit to the usual cytology schedule may be an effective approach in the follow-up after LEEP.

Pap Smear Combined with HPV Testing: A Reasonable Tool for Women with High-grade Cervical Intraepithelial Neoplasia Treated by LEEP

  • Mo, Ling-Zhao;Song, Hong-Lin;Wang, Jian-Li;He, Qing;Qiu, Zhang-Can;Li, Fei
    • Asian Pacific Journal of Cancer Prevention
    • /
    • 제16권10호
    • /
    • pp.4297-4302
    • /
    • 2015
  • Background: To evaluate HPV testing by Hybrid Capture II (HCII) in conjunction with cytology in detecting the residual/recurrence disease after treatment of high-grade cervical intraepithelial neoplasia (CIN II-III) with loop electrosurgical excision procedure (LEEP). Materials and Methods: A retrospective review of 158 patients with histologically confirmed CIN II-III who underwent LEEP between January 2011 and October 2012 was conducted. Post-treatment control was scheduled at the 3rd, 6th, 12th and 18th month. All patients were followed up by Pap smear and HR-HPV genotype and viral load testing. Results: Pre-treatment, HR-HPV DNA, was detected in all specimens of the patients. At follow-up, 25 patients were diagnosed as the residual/recurrent disease during the FU visit, among whom, 16 patients with positive margin: 13 patients (52%) with HR-HPV DNA+/cytology+, 2 patients (8%) with HR-HPV DNA+/cytology-, 1 patient (4%) with cytology+/HR-HPV DNA-; 9 patients with clean margin - 5 patients (55.6%) with HR-HPV DNA+/cytology+; 2 patients (22.2%) with HRHPV DNA+/cytology-, 2 patients (22.2%) with cytology+/HR-HPV DNA-. None of them persisting HR-HPV DNA-/cytology-with positive or negative margin was identified as the residual/recurrent disease. The majority of residual/recurrent disease was detected at the 12th and 18th month FU, and there was almost no difference in the sensitivity and negative predictive value (NPV) between at the 3rd month and the 6th month FU visits. 14 residual/recurrence disease (14/46:30.4%) had pre-treatment high viral load (>5 000 RUL/PC) and 11 (11/112, 9.8%) with pre-treatment low viral load, P<0.05. Conclusions: (1) The persistence HR-HPV DNA is the root cause of the residual/recurrent disease for the women treated for high-grade CIN; the pre-treatment viral load and margin can be seen as the predictor. (2) The FU visit beginning at the 6th month post-treatment and lasting at least 24 months with the combination of cytology and HPV testing. (3) Patients with high pre-treatment HPV load, which is considered as one risk of developing the residual/recurrent disease, should be paid more attention (especially above 500RUL/PC) to by clinicians.

아라미드섬유의 표면개질에 의한 시멘트 복합재료의 강도특성 및 내충격성능의 향상효과 (Improvement of the Strength Properties and Impact Resistance of the Cement Composite Materials by the use of Surface Modification of the Aramid Fibers)

  • 남정수;유재철;김규용;김홍섭;전중규
    • 한국구조물진단유지관리공학회 논문집
    • /
    • 제19권1호
    • /
    • pp.100-108
    • /
    • 2015
  • 본 연구의 목적은 아라미드섬유의 표면개질에 의한 시멘트 복합재료의 강도특성 및 내충격성능의 향상효과를 평가하는 것이다. 단섬유 형태의 아라미드섬유를 섬유길이와 섬유의 표면유제처리율을 달리하여 시멘트 복합재료에 혼입하였다. 아라미드섬유보강 시멘트 복합재료의 강도특성은 섬유의 혼입율, 섬유의 표면유제처리율, 섬유의 길이에 따라 다르게 나타났으며, 특히, 동일한 섬유혼입율 및 섬유길이에 대한 인장강도 및 휨강도는 섬유의 표면유제처리율을 증가시킨 시험체가 향상되는 경향을 확인하였다. 이러한 정적 강도특성 결과는 고속비상체의 충돌에 의한 내충격성능에도 영향을 미쳤으며, 아라미드섬유의 표면유제처리율이 증가함에 따라 배면박리가 억제되는 것을 알 수 있었다. 하지만, 아라미드섬유를 섬유보강 시멘트 복합재료용 보강재로 활용하기 위해서는 섬유와 시멘트 복합재료간의 분산능력 및 부착효율을 향상시켜야 할 것으로 판단된다. 이는 아라미드섬유의 표면특성을 소수성으로 개질하는 것에 의해 가능할 것으로 사료되며, 1.2 %이상의 표면유제처리율 및 성능개선에 대해서는 추가적인 검토가 필요할 것으로 판단된다. 또한, 아라미드섬유와 후크형 강섬유를 하이브리드 한 시험체의 경우, 강도특성 및 내충격성능의 향상효과는 강섬유의 기여도가 높은 것으로 나타났다.

Deconstructionism in Issey Miyake's Fashion Design

  • Kwon, Hae-Sook
    • 패션비즈니스
    • /
    • 제11권6호
    • /
    • pp.87-100
    • /
    • 2007
  • This study aims at analyzing the characteristics of deconestructionism expressed in Issey Myake's fashion who is one of the most creative designers in the world. Method and contents of this study are as follows. Through the review of literatures, three major categories such as interminacy of meaning, decentring, and intertextuality and eight subcategories have been identified as major features of deconestructionism. These subcategories for content analysis were selected to examine the characteristics of deconstructionism expressed in Issey Myake's design in depth. Interminacy of meaning was divided into unstructured and unconstructed factors while decentring into qualities of cross-gender, subculture, anti-fashion, and post-humanism. Lastly, intertextuality was classified into factors of disordered mixing mode and mixed styles. Materials for analysis were chosen from total 349 designs on the website,www.firstview.com, which carries Issey Miyake's collection from 2002 S/S through 2006 F/W. 2 fashion major analysts including the researcher participated in 1st analysis and two another fashion major analysts participated in 2nd analysis. The final level of consistency between analysts was over 97% for all categories. The data analysis quantitatively evaluates the frequency of each category and qualitatively evaluates the characteristics of design. The result is as follows. First, the avant-garde facets of inter-textuality are most prominent. In particular, Miyake has introduced the various novelly textiles to fashion and employed the mixtured styles, not to copy them but to create hybrid designs by using pastiches and mixing fashion styles. Moreover, he has used various fabrics in order to inflict shock and contrast but still create subtle harmony, thus enriching his fashion. Second, the indeterminacy of meaning is the second most frequently shown facet of Miyake's fashion design. Miyake has employed unconstructed expression techniques, which has projected unusual images free from basic forms of designs and also has used the unstructured styles which dismantle harmony and balance-the common rule of design. He has made a new attempt to acknowledge clothing as an expressive artwork by allowing clothes to take a complete form when a person actually wears them. He has demonstrated a unique perspective on cloth construction and presented a love for artistic collaboration in the development of his collections A distinct manufactured aesthetic is exaggerated, even hyperbolic. Thirdly, the aspects of decentralization were also shown in Miyake's design, however, it has been visibly decreased after 2002 S/S.

녹색꽃양배추 (Brassica oleracea L. var. italica)의 약배양 효율증진과 약유래 계통의 특성 (Factors Affecting Efficiency of Anther Culture and Phenotypic Characteristics of Anther -derived Progeny in Broccoli)

  • 남시춘;윤광현;백기엽
    • 식물조직배양학회지
    • /
    • 제26권3호
    • /
    • pp.189-195
    • /
    • 1999
  • 녹색꽃양배추의 약배양에 영향을 미치는 제 조건을 규명하고 다양한 유전적인 특성을 가진 품종들을 대상으로 다수의 계통을 유기하여 신품종 육성 소재로 이용하고자 실험한 결과는 다음과 같다. 배지시험 결과 B5배지에 NAA 0.1 mg/L + 2.4-D 0.1mg/L + 당 10% 처리구에서 배상체 발생율이 가장 높았으며 액체배지가 고체배지보다 5배 정도 배발생에 효과적이었다. 약접종 직후 35$^{\circ}C$ 고온처리 일수에 따른 시험에서는 1일처리가 가장 효과적이었으며 시일이 경과할수록 배상체 발생율이 현저히 저하되었다 품종간 배상체 유기율은 Green valient 2.8%에서 Haisi의 21%까지 차이가 심하였으나 이배체율은 62~74%로 품종간 큰 차이를 나타내지 않았다. Rokguray와 Haisi두 품종 약유래 계통의 포장특성 검정결과 초장, 엽수, 측지수, 화뢰의 지름은 다양한 변이를 보였으며 두 품종에서 유기된 계통들 중 조숙이며 초장이 크고 화뢰의 지름이 큰 계통과 중만생이며 엽수가 많고 화뢰의 지름이 작은 계통을 각각 5계통, 7계통을 선발하여 F$_1$육성 소재로 이용하였다.

  • PDF