• 제목/요약/키워드: Non-homogeneity

검색결과 230건 처리시간 0.02초

FRP 복합재료의 온도변화 및 제작인자별 비선형 전단거동 조사 (An Investigation on the Nonlinear Shear Behavior of FRP Composites Considering Temperature Variation and Fabricating Parameters)

  • 정우영;황진섭
    • 대한토목학회논문집
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    • 제33권3호
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    • pp.833-841
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    • 2013
  • 복합재료의 경우 다양한 재료에 따라 제작이 가능하며 이들 완성재료의 경우 다양한 재료특성을 나타낸다. 이 연구는 건설용 FRP복합재료의 재료특성 중 선형거동이 뚜렷이 나타나는 인장, 압축과는 달리 비선형 거동이 발생되는 전단거동 특성에 대한 실험적 연구로서 ASTM D4255 규정에 의한 2-Rail 전단시험 방법을 토대로 각각의 시편들을 제작, 실험결과를 분석하였다. 고려된 실험변수로는 함침 수지류의 종류와 섬유 체적비, 섬유배열 방향 및 온도 특성, 공장용 생산제품의 균질성 등을 고려하였다. 섬유배열 방향에 따른 특성조사의 경우 섬유 배열방향을 $0^{\circ}$, $30^{\circ}$, $45^{\circ}$, $60^{\circ}$로 각각 시편을 제작하였으며, 온도에 따른 외부환경 변화에 의한 FRP재료의 전단거동을 조사하기 위하여 실험온도를 $25^{\circ}C$, $40^{\circ}C$, $60^{\circ}C$, $80^{\circ}C$로 각각 고려하여 시험을 수행하였다. 이 연구를 통하여 대부분의 복합재료 시편에서 비선형 전단거동이 확인되었으며 비닐에스테르수지를 사용하고, 높은 섬유체적비와 $45^{\circ}$의 섬유배열방향을 가진 시편에서 비선형 전단거동이 가장 두드러지게 나타나는 것으로 조사되었다. 온도변화에 따른 실험결과의 경우, 온도가 증가함에 따라 전단 내 비선형 거동의 감소가 나타났으며 공장용 제작제품의 경우 hand lay-up 제작시편에 비하여 비선형 전단거동이 비교적 동등하게 나타냈다.

Characterization and Action Patterns of Two ${\beta}$-1,4-Glucanases Purified from Cellulomonas uda CS1-1

  • Yoon, Min-Ho;Choi, Woo-Young
    • Journal of Microbiology and Biotechnology
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    • 제17권8호
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    • pp.1291-1299
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    • 2007
  • Two ${\beta}$-1,4-glucanases (DI and DIII fractions) were purified to homogeneity from the culture filtrate of a cellulolytic bacteria, Cellulomonas sp. CS 1-1, which was classified as a novel species belonging to Cellulomonas uda based on chemotaxanomic and phylogenetic analyses. The molecular mass was estimated as 50,000 Da and 52,000 Da for DI and DIII, respectively. Moreover, DIII was identified as a glycoprotein with a pI of 3.8, and DI was identified as a non-glycoprotein with a pI of 5.3. When comparing the ratio of the CMC-saccharifying activity and CMC-liquefying activity, DI exhibited a steep slope, characteristic of an endoglucanase, whereas DIII exhibited a low slope, characteristic of an exoglucanase. The substrate specificity of the purified enzymes revealed that DI efficiently hydrolyzed CMC as well as xylan, whereas DIII exhibited a high activity on microcrystalline celluloses, such as Sigmacells. A comparison of the hydrolysis patterns for pNP-glucosides (DP 2-5) using an HPLC analysis demonstrated that the halosidic bond 3 from the nonreducing end was the preferential cleavage site for DI, whereas bond 2, from which the cellobiose unit is split off, was the preferential cleavage site for DIII. The partial N-terminal amino acid sequences for the purified enzymes were $^1Ala-Gly-Ser-Thr-Leu-Gln-Ala-Ala-Ala-Ser-Glu-Ser-Gly-Arg-Tyr^{15}$-for DI and $^1Ala-Asp-Ser-Asp-Phe-Asn-Leu-Tyr-Val-Ala-Glu-Asn-Ala-Met-Lys^{15}$-for DIII. The apparent sequences exhibited high sequence similarities with other bacterial ${\beta}$-1,4-glucanases as well as ${\beta}$-1,4-xylanases.

터널 간섭에 따른 지반의 공간 구역화 및 지반공학적 특성 분석 (Spatial Ground Zoning and Analysis of Geotechnical Characteristics Considering Tunnel Interface)

  • 전제성;김용성;김기영
    • 한국구조물진단유지관리공학회 논문집
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    • 제9권4호
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    • pp.252-260
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    • 2005
  • 본 연구에서는 ${\bigcirc}{\bigcirc}$지역에서의 터널 간섭사례에 따른 적정 지반 구역화 및 각 구역별 특성치 분석을 수행하였다. 본 대상 지역은 호상흑운모 편마암 및 흑운모 편암, 화강 편마암이 심도와 평면상에서 불규칙하게 분포하고 있는데, 전반적으로 풍화대가 깊게 분포하고 있으며, 단층대 및 파쇄대가 깊은 심도에서도 대규모로 분포하고 있었다. 본 사례에서와 같이 특정 간섭부분의 공간적 지층특성 구분이 향후 안정성 분석 및 설계반영에 매우 중요하게 작용하는 경우, 기존 터널설계시의 지층구분 및 대표 특성치 산정 방식은 적정 지층특성 분석에 많은 한계점을 지니고 있었다. 본 연구결과, 각종 지반조사 결과의 종합 및 분석을 통해 공간적 지층구분 및 적정 특성치 산정이 향후 안정성 검토 등에 있어 매우 유효하게 적용됨을 알 수 있었다.

비위관 영양방법 개선에 따른 간호효과 비교 (A comparison of nursing effects after the improvement of nasogastric tube feeding method)

  • 최자윤;장금성;황선영
    • 간호행정학회지
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    • 제8권4호
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    • pp.645-654
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    • 2002
  • Purposes : This study was conducted to examine nursing effects after using a new method of nasogastric tube feeding with recycled PETE bottle making use of gravity, and to compare with those of bolus method using syringe and pressure. Methods : The data collected from patients with nasogastric tube feeding more than a week at an internal medicine unit of C university hospital located in G-city from January 1st, 1998 through June 30th, 2000. For this nonequivalent control group posttest non-synchronized design, 28 patients were assigned to an experimental group and 35 patients to a control group. The homogeneity of two groups and the dependent variables were tested with use of $x^2-test$ and t-test. Results : The duration of hemostatic use was significantly shorter in the experimental group than control group(t=2.63, p=0.02). Also, the patients with PETE bottle feeding had a lower cost of material(t=3.51, p=0.01) and a lower rate of the time of direct nursing care(t=2.44, p=0.04) than those of control group. But, there was no significant difference between two groups in the length of hospital stay. Conclusion : This results indicates that nasogastric tube feeding with PETE bottle is superior to nasogastric tube feeding with syringe. This findings gave us an evidence to enhance nursing effectiveness in clinical setting.

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Development of recombinant human chorionic gonadotropin (hCG) using high-density culture technique of suspension-adapted chinese hamster ovary (CHO) cells

  • Na, Kyu-Heum;Kim, Seung-Chul;Seo, Kwang-Seok;Lee, Sung-Hee;Kang, Soo-Hyung
    • 한국생물공학회:학술대회논문집
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    • 한국생물공학회 2005년도 생물공학의 동향(XVI)
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    • pp.37-37
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    • 2005
  • Human chorionic gonadotropin (hCG) is a heterodimeric glycoprotein hormone consisting of non-covalently linked two subunits, the ${\alpha}$ and ${\beta}$ subunit. It has been used as a infertility drug for ovulation to mimic luteinizing hormone $(LH).^{1)}$ A stable cell line was established by transfection of Rc/CMV-i-dhfr-hCG, expression vector containing hCG ${\alpha}-$ and ${\beta}-genes$, into dihydrofolate reductase-deficient CHO cells and subesquent methotrexate-mediated gene amplification. Anchorage-dependent CHO cells were adapted into a serum-free and/or animal component-free suspension medium through gradual serum weaning for the hCG production. The established cell line showed typical morphological characteristics and growth profile of CHO cells, and could produce FSH with passage-to-passage consistency. The high density perfusion culture of the CHO cells was carried out in Celligen Plus bioreactor equipped with a spin-filter as a internal cell retention device. The cell density reached up to $>1x10^{7}$ cells/ml in less than 7 days and a perfusion-control strategy based on cellular consumption rates of glucose was $established.^{2)}$ Biologically active recombinant hCG was purified by a series of chromatographic steps including anion exchange chromatography and hydrophobic interaction chromatography to homogeneity. The highly purified recombinant hCG was characterized for physicochemical, immunological and biological properties.

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Prognostic factors associated with the success rates of posterior orthodontic miniscrew implants: A subgroup meta-analysis

  • Hong, Sung-Bin;Kusnoto, Budi;Kim, Eun-Jeong;BeGole, Ellen A;Hwang, Hyeon-Shik;Lim, Hoi-Jeong
    • 대한치과교정학회지
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    • 제46권2호
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    • pp.111-126
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    • 2016
  • Objective: To systematically review previous studies and to assess, via a subgroup meta-analysis, the combined odds ratio (OR) of prognostic factors affecting the success of miniscrew implants (MIs) inserted into the buccal posterior region. Methods: Three electronic searches that were limited to articles on clinical human studies using MIs that were published in English prior to March 2015 were conducted. The outcome measure was the success of MIs. Patient factors included age, sex, and jaw of insertion (maxilla vs. mandible), while the MI factors included length and diameter. A meta-analysis was performed on 17 individual studies. The quality of each study was assessed for non-randomized studies and quantified using the Newcastle-Ottawa Scale. The meta-analysis outcome was a combined OR. Subgroup and sensitivity analyses based on the study design, study quality, and sample size of miniscrews implanted were performed. Results: Significantly higher success rates were revealed for MIs inserted in the maxilla, for patients ${\geq}20$ years of age, and for long MIs (${\geq}8mm$) and MIs with a large diameter (> 1.4 mm). All subgroups acquired homogeneity, and the combined OR of the prospective studies (OR, 3.67; 95% confidence interval [CI], 2.10-6.44) was significantly higher in the maxilla than that in the retrospective studies (OR, 2.10; 95% CI, 1.60-2.74). Conclusions: When a treatment plan is made, these risk factors, i.e. jaw of insertion, age, MI length, and MI diameter, should be taken into account, while sex is not critical to the success of MIs.

폐암 세기변조방사선치료 시 최적화된 조사계획 설정과 가상 장기 설정에 관한 연구

  • 이석;이창걸;조삼주;추성실;이상훈;최명선;김철용
    • 한국의학물리학회:학술대회논문집
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    • 한국의학물리학회 2003년도 제27회 추계학술대회
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    • pp.34-34
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    • 2003
  • 목적 : 폐암 환자 세기변조방사선치료 과정을 소개하고, 방사선치료계획의 최적화를 위한 빔 수와 방향, 가상장기 설정 (virtual organ delineation, VOD) 및 선량 제한 인자들의 이용에 대해 평가함으로써 폐, 심장 등에 조사되는 선량을 최소화하는데 사용하는 세기변조방사선치료 (intensity modulated radiotherapy, IMRT) 기술의 유용성을 평가하고자한다. 대상 및 방법 : 종양이 종격동을 침범하여 상대적으로 장기움직임에 의한 오차가 적은 폐암환자 5 명을 대상으로 하였다. 환자고정장치는 상반신을 편안하게 유지함과 동시에 팔의 위치를 고정시킴으로써 기대할 수 있는 환자고정효과와 벨트를 이용하여 환자 상복부를 압박해줌으로써 호흡운동에 의한 장기 움직임을 감소시킬 수 있는 형태로 고안하였다. 치료계획시 빔 수와 방향은 5,7,9 문 (from 200 to 160, equispaced field, arbitrary field), 4 문 (anterior, posterior, bilateral posterior oblique field) 과 비등방 7, 9 문 (non-equispaced field, arbitrary field) 등을 사용하였다. 선량제한 ($V_{20}V_{25}$)은 문헌에 기초하여 설정하였으며, 가상장기를 적절히 사용하여 최적화된 치료계획 결과를 얻었다. 방사선치료계획 평가는 선량-체적간 히스토그람 (DVH), 등선량곡선 및 선량통계 등을 이용하여 수행하였다. 특히 가상장기 설정 전, 후의 결과 값을 분석함으로써 그 유용성을 확인하였다. 결과 : 9문 등방-IMRT와 7문 비등방-IMRT 방법이 치료계획용적의 선량균질성 (PTV dose homogeneity), 평균 폐선량 (mean lung dose) 및 $V_{20}V_{25}$ 모두에서 20% 이내의 좋은 결과를 얻을 수 있었고, 가상 장기를 설정함으로써 같은 결과를 가져옴을 알 수 있었다. 또한 폐암 세기변조방사선치료 프로토콜을 작성하여 임상에 사용함으로써 치료과정 중 발생할 수 있는 오류를 보완할 수 있음을 알 수 있었다. 결론 : 폐암 세기변조방사선치료 시 사용할 수 있는 프로토콜을 작성하였고, 적절한 가상 장기 및 조사계획 설정으로 치료계획의 최적화를 얻을 수 있음을 알 수 있었다.

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Sweet BV의 조제물 농도분석 및 안정성 확인을 위한 시험적 연구 (Experimental studies of validation and stability of Sweet Bee Venom using HPLC)

  • 강계성;권기록
    • 대한약침학회지
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    • 제12권4호
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    • pp.33-50
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    • 2009
  • Objectives : This study was conducted to confirm validation and stability of concentration analysis method of pure melittin (Sweet Bee Venom-Sweet BV) extracted from the bee venom by utilizing protein isolation method of gel filtration. Methods : All experiments were conducted at Biotoxtech, a non-clinical studies authorized institution, under the regulations of Good Laboratory Practice (GLP). Standard solutions of melittin (SIGMA, USA) and test substances were dispensed and were analyzed with HPLC for Sweet BV to secure the validation of analysis. Results : 1. Measurement of system suitability of Sweet BV satisfied criterion of below 3%. 2. Confirming Linearity of Sweet BV in 10-200${\mu}g/m\ell$ solution yielded correlation coefficient (r) of 0.995 and accuracy of 85-115% which satisfy criterion. 3. Measurement of Specificity of Sweet BV didn't yield any substance affecting the peak of test substances, but detected at 21.22min verified as the test substance. 4. Confirming Intra-day of Sweet BV, accuracy and precision of 0.1, 100${\mu}g/m\ell$ were 105.70, 95.81 and 0.66, 0.73, respectively, satisfying both criteria of accuracy (85-115%) and precision (within 10%). 5. To measure Stability in autosampler, all samples used in Intra-day reproducibility sat in the autosampler for five hours and were re-analyzed. Both variability and precision satisfied the criteria. 6. Homogeneity of Sweet BV (0.1, 100${\mu}g/m\ell$) at upper, middle, and lower layers all satisfied the accuracy and precision criteria. 7. Stability of Sweet BV (0.1, 100${\mu}g/m\ell$) at room temperature for four hours and refrigerated for 7 days all satisfied the criterion. 8. For the measurement of Quality control, QC samples measured on the first and eighth day all satisfied accuracy and precision criteria. Conclusion : Above experiment data satisfies validation and stability of concentration analysis method of Sweet BV.

복강경담낭절제술 후 가온요법 간호중재 프로그램 적용 효과 (Study on Effect of Warmth Therapy Nursing Intervention Program after Laparoscopic Cholecystectomy)

  • 이중근
    • 한국산학기술학회논문지
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    • 제21권7호
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    • pp.350-356
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    • 2020
  • 목적: 본 연구는 수술 후 회복실에 입실한 환자에게 가온요법 간호중재 프로그램이 미치는 효과를 파악하여 간호중재방안 개발 및 기초자료를 제시하고자 시도된 비 동등성 대조군 유사 실험연구이다. 연구방법: 연구의 대상자는 가온요법 프로그램을 적용한 실험군 31명, 대조군 31명을 대상으로 실시하였다. 가온요법은 가온기를 통해 회복실에서 38~43℃ 범위 내 가온하였다. 대상자의 일반적 특성은 실수와 백분율로 파악하였고, 실험군과 대조군의 동질성 검정은 𝑥2-test와 In-dependent t-test로 파악하였다. 실험군과 대조군의 시간에 따른 체온, 통증, 전율의 차이는 repeated measure ANOVA로 파악하였다. 실험군과 대조군의 온도 편안감의 차이는 t-test로 파악하였다. 결과: 첫째, 수술 직후 반복 측정 결과 실험군과 대조군의 체온, 통증, 전율이 유의한 차이를 보였다. 둘째, 온도 편안감은 유의한 차이를 보였다. 결론: 이와 같이 수술 후 가온요법 중재 시 환자에게 긍정적인 효과가 있는 것을 확인할 수 있었다.

Applying a Forced Censoring Technique with Accelerated Modeling for Improving Estimation of Extremely Small Percentiles of Strengths

  • Chen Weiwei;Leon Ramon V.;Young Timothy M.;Guess Frank M.
    • International Journal of Reliability and Applications
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    • 제7권1호
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    • pp.27-39
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    • 2006
  • Many real world cases in material failure analysis do not follow perfectly the normal distribution. Forcing of the normality assumption may lead to inaccurate predictions and poor product quality. We examine the failure process of the internal bond (IB or tensile strength) of medium density fiberboard (MDF). We propose a forced censoring technique that closer fits the lower tails of strength distributions and better estimates extremely smaller percentiles, which may be valuable to continuous quality improvement initiatives. Further analyses are performed to build an accelerated common-shaped Weibull model for different product types using the $JMP^{(R)}$ Survival and Reliability platform. In this paper, a forced censoring technique is implemented for the first time as a software module, using $JMP^{(R)}$ Scripting Language (JSL) to expedite data processing, which is crucial for real-time manufacturing settings. Also, we use JSL to automate the task of fitting an accelerated Weibull model and testing model homogeneity in the shape parameter. Finally, a package script is written to readily provide field engineers customized reporting for model visualization, parameter estimation, and percentile forecasting. Our approach may be more accurate for product conformance evaluation, plus help reduce the cost of destructive testing and data management due to reduced frequency of testing. It may also be valuable for preventing field failure and improved product safety even when destructive testing is not reduced by yielding higher precision intervals at the same confidence level.

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