• 제목/요약/키워드: I-solution

검색결과 3,965건 처리시간 0.028초

ON NEWTON'S METHOD FOR SOLVING A SYSTEM OF NONLINEAR MATRIX EQUATIONS

  • Kim, Taehyeong;Seo, Sang-Hyup;Kim, Hyun-Min
    • East Asian mathematical journal
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    • 제35권3호
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    • pp.341-349
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    • 2019
  • In this paper, we are concerned with the minimal positive solution to system of the nonlinear matrix equations $A_1X^2+B_1Y +C_1=0$ and $A_2Y^2+B_2X+C_2=0$, where $A_i$ is a positive matrix or a nonnegative irreducible matrix, $C_i$ is a nonnegative matrix and $-B_i$ is a nonsingular M-matrix for i = 1, 2. We apply Newton's method to system and present a modified Newton's iteration which is validated to be efficient in the numerical experiments. We prove that the sequences generated by the modified Newton's iteration converge to the minimal positive solution to system of nonlinear matrix equations.

Effect of addition of methanol on rheological properties of silk formic acid solution

  • Bae, Yu Jeong;Um, In Chul
    • International Journal of Industrial Entomology and Biomaterials
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    • 제40권1호
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    • pp.28-32
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    • 2020
  • Recently, many studies have been undertaken on the wet spinning and electrospinning of silk because wet-spun fibers and electrospun webs of silk can be applied in the biomedical and cosmetic fields owing to the good biocompatibility of silk. The rheological properties of silk solution are important because they strongly affect the spinning performance of the silk solution and the structures of resultant fibrous materials. Therefore, as a preliminary study on the effect of solvent composition on the rheological properties of silk fibroin (SF) solution and structure of the resultant film, in the reported work, methanol was added to the SF formic acid solution. A small amount of methanol (i.e. 2%) added to the SF formic acid solution significantly altered the rheological properties of the solution: its shear viscosity increased by 10 folds at low shear and decreased on increasing the shear rate, demonstrating shear thinning behavior of the SF solution. Dynamic tests for the SF solution indicated that the addition of 2% methanol altered the viscous state of the SF formic acid solution to elastic. However, the molecular conformation (i.e. β-sheet conformation) of the regenerated SF film cast from formic acid remained unchanged on the addition of 2% methanol.

적출 쥐 심장의 장시간 보존에 있어서 University of Wisconsin 수정 용액의 우수성 (Superiority of Modifiled University of Wiscinsin Solution in the Prolonged Preservation of Isolated Rat Heart)

  • 이재성;김송명;김규태
    • Journal of Chest Surgery
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    • 제26권6호
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    • pp.427-440
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    • 1993
  • The paucity of donor hearts for transplantation can be remedied by distant heart procurement. Prolonging donor heart preservation is essential for successful clinical cardiac transplantation. Thirty-two isolated rat hearts were perfused with Krebs-Henseleit buffer solution for 15 minutes, arrested and preserved at 4 oC for 4 hours, and then reperfused for 25 minutes. The following three groups were prepared and hemodynamic changes, creatine kinase-MB isoenzyme levels and ultrastructural changes of the myocardium were analysed before and after cardiac arrest. ; Group I : the heart was arrested with the cardioplegic solution [Plegisol, potassium : 16 mM, sodium : 120 mM] and then stored in a solution with ionic compositions of the extracellular fluid [Hartman, potassium : 4 mM, sodium : 130 mM] ; Group II : the heart was arrested with the cardioplegic solution and stored in a solution with ionic compositions of the intracellular fluid [Modified Euro-Collins, potassium : 108 mM, sodium : 10 mM] ; Group III : the heart was arrested with the cardioplegic solution containing adenosine 20 uM, and then stored in a solution with ionic compositions of the intracellular fluid [Modified University of Wisconsin solution, potassium : 119 mM, sodium: 23 mM]. Left ventricular developed pressure at 20 minutes of the reperfusion was significantly higher in group III [64.3 $\pm$ 3.12 mmHg, p<0.01] and group II [58.3 $\pm$ 1.55 mmHg, p<0.05] as compared with group I [51.4$\pm$ 2.78 mmHg]. The time to induce cardiac arrest after infusion of cardioplegic solution with adenosine 20 uM [5.3 $\pm$ 0.30 second, p<0.005] was significantly shorter than without adenosine [10.6$\pm$ 0.55 second]. Coronary flow at 20 minutes of the reperfusion was augmented significantly in group III [9.6$\pm$ 0.50 ml/min, p<0.05, p<0.05] as compared with group I [8.0 $\pm$ 0.41 ml/min] and group II [8.1$\pm$ 0.51 ml/min]. Percentage recovery of left ventricular developed pressure at 20 minutes of the reperfusion was significantly higher in group III [94.6$\pm$ 2.51 %, p<0.005] as compared with group II and in group II [83.1 $\pm$ 1.22 %, p<0.005] as compared with group I [69.9 $\pm$ 1.73 %], and also percentage recovery of coronary flow at 20 minutes of the reperfusion was significantly higher in group III [82.3 $\pm$ 3.86 %, p<0.05] as compared with group II [71.4 $\pm$ 3.46 %] but there was no significant difference between group I and group II. Measured level of creatine kinase-MB isoenzyme at 15 minutes of the reperfusion was significantly lower in group III [1.23 $\pm$ 0.16 ng/ml, p<0.025] and group II [1.42$\pm$ 0.10 ng/ml, p<0.05] as compared with group I [1.79 0.14 ng/ml]. In the semiquantitative evaluation of the ultrastructural changes of the myocardium, mitochondrial score was lower in group III [0.7 $\pm$ 0.21] than in group I [3.1$\pm$ 0.28] and group II [1.7 $\pm$ 0.19], and also the other structural score was lower in group III [2.7$\pm$ 0.99] than in group I [7.9 $\pm$ 0.89] and group II [5.0 $\pm$ 1.22]. In conclusion, the solution with ionic compositions of the intracellular fluid is appropriate for prolonged cardiac preservation, and it appears to be better preserving method for distant procurement when the donor heart is rapidly arrested with cardioplegic solution containing adenosine 20 uM, and then stored with Modified University of Wisconsin solution.

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방정식의 해법에 관한 소고

  • 이대현
    • 한국수학사학회지
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    • 제17권1호
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    • pp.61-68
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    • 2004
  • This paper aims at investigating the algebraic solution of cubic and quartic equation and eliciting the didactical meanings of them. First, I examine the event which relates to the equation in the history of mathematics and investigate the algebraic solution of cubic and quartic equation. And then I elicit the didactical suggestions which are required of teachers and students when they investigate the algebraic solution of cubic and quartic equation. In general, the investigation of these solutions is the valuable task which requires the algebraic intuition and technique for students and certificates expert knowledge for teachers.

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초음파가 유기화합단위공정에 미치는 영향 (I) glucose 수용액의 산화에 관하여 (Ultrasonic Wave Effect on the Unit-process of Organic Synthesisi I. Oxydation of Aqueous Glucose Solution)

  • 국채호;조윤상
    • 약학회지
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    • 제13권1호
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    • pp.16-21
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    • 1969
  • When ultrasonic wave with barium titanate as an ultrasonic transducer (96.84kc, 1.4kv, 240mA) was applied to a dilute glucose solution, glucose was oxidized to glucuronic acid. It was found that the lower the glucose concentration, the higher the oxidation rate. The aeration and the presence of ferrous sulfate as a catalyst were found to increase the rate. The optimal duration for applying the wave to the solution was found to be six hours.

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FRP-콘크리트 계면의 부착모델 I: 이론적 연구 (Bond-Slip Model for FRP-Concrete Interlace I: Theoretical Approach)

  • 조근희;조정래;김병석;이영호;진원종;김성태
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2003년도 봄 학술발표회 논문집
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    • pp.853-858
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    • 2003
  • A new method is proposed to obtain bond-slip model for an adhesive joint between FRP and concrete. Interface element, which can describe the bond behavior, is developed in order to overcome the restriction that complex constitutive relations cannot be modeled in analytic solution. Calibrating numerical bond-slip model to experimental results, multi-objective optimization problem is constructed by physical programming method, and is solved using genetic algorithm. The validity of proposed method is demonstrated by comparing known analytic solution and numerically optimized solution.

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STABILITY OF POSITIVE PERIODIC NUMERICAL SOLUTION OF AN EPIDEMIC MODEL

  • Kim, Mi-Young
    • Korean Journal of Mathematics
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    • 제13권2호
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    • pp.149-159
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    • 2005
  • We study an age-dependent s-i-s epidemic model with spatial diffusion. The model equations are described by a nonlinear and nonlocal system of integro-differential equations. Finite difference methods along the characteristics in age-time domain combined with finite elements in the spatial variable are applied to approximate the solution of the model. Stability of the discrete periodic solution is investigated.

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실리콘 태양전지 질산침출액에서 LIX63를 이용한 은(Ag) 회수 (Recovery of Silver from Nitrate Leaching Solution of Silicon Solar Cells)

  • 조성용;김태영;쑨판판
    • 자원리싸이클링
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    • 제30권2호
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    • pp.39-45
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    • 2021
  • 폐 태양광전지 처리과정에서 은은 실리콘 및 알루미늄을 회수 위해 제거 하거나 처리하지않고 버리고있는 현실이다. 경제적 및 환경 보호 측면에 폐 태양광전지부터 은의 회수 중요하다고 판단함. 선행연구에서 1 mol/L 질산, 반응온도 70도, 반응시간 2h로 폐 태양광전지부터 Ag, Al을 침출 하었다. 이 침출액으로부터 은을 회수하기 위해 추출제 LIX63 및 탈거제 암모니아수 이용하였다. 추출 및 탈거 효율에 영향 미치는 조건: 침출액 pH, 금속이온 농도, 추출제의 농도, A/O ratio(수상 및 유기상 부피비율), 탈거제 농도 및 탁거과정에서 A/O ratio등을 변화시켜 조차하였다. McCabe-Thiele plots로부터 Ag(I)의 추출 및 탈거에 대한 이론 단수를 구하였으며, 향류 다단 모의 추출 시험을 통해 Ag(I)의 추출과 탈거에 대한 효율이 각각 >99.99%, 98.9% 이었다. Ag(I)와 Al(III)의 순도는 각각 99.998% 와 99.99%이었으며, 질산 침출액으로부터 Ag(I)및 Al(III)을 회수하기 위한 공정도를 제안하였다.

마이크로 믹서에서 와도 지수에 의한 비용해성 물질의 혼합 예측 (Prediction of Degree of Mixing for Insoluble Solution with Vortex Index in a Passive Micromixer)

  • 조일대;김범중;맹주성
    • 대한기계학회논문집B
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    • 제29권2호
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    • pp.232-238
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    • 2005
  • The 'Mixing Index($D_I$)' is used as a conventional guidance measuring the degree of mixing for multiphase flows. For the case when insoluble solutions flow in a passive micromixer, a new method to calculate $D_I$ is proposed. The 'Vortex Index(${\Omega}_I$)' is suggested and formulated. We infer that ${\Omega}_I$ relates to the degree of chaotic advection. Various arbitrary shaped microchannels were tested to calculate the $D_I\;and\;{\Omega}_I$, and then a simple algebraic equation, $D_I=Aexp(B{\Omega}_I)$, is obtained. This equation may be used instead of the conventional partial differential equation, concentration equation, to estimate the degree of mixing.

유근피(楡根皮) 약침이 lipopolysaccharide 유발 류마티스 관절염 모델에서 MIF 활성 억제에 미치는 영향 (The Effectiveness of Ulmus Davidiana Planch Herbal Acupuncture to Inhibit MIF Activation on Lipopolysaccharide-induced Rheumatoid Arthritis Model)

  • 변혁;박인식;조현석;김갑성;이승덕
    • Journal of Acupuncture Research
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    • 제23권6호
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    • pp.117-132
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    • 2006
  • Objectives : The purpose of this study is to investigate the effect of Ulmus davidiana Planch herbal acupuncture solution in LPS-stimulated RAW 264.7 cells and mouse knee joints, perfom1ed several experimental items: those are MIF mRNA, MIF, $TNF-{\alpha}$, $NF-{\kappa}B$ p65, iNOS mRNA, iNOS, NO, synovial hyperplasia, angiogenesis and fibrosis. Methods : In order to observe mRAN expression of MIF and iNOS in LPS-stimulated RAW 264.7 cells, RT-PCR was used. NO production in LPS-stimulated RAW 264.7 cells was measured by nitrite assay. All the female BALB/c mice were bred and maintained in pathogen-free mouse colonies and were 6 weeks of age on beginning of the experiment. The experimental model of RA was induced by injection of $50{\mu}g/kg$ LPS. Ulmus davidiana Planch herbal acupuncture solution was injected into either S 35 (犢鼻) or EX-LE 202 (內膝眼) of mice in turn daily for 19 days. Immunohistochemical staining was carried out to assess $TNF-{\alpha}$, $NF-{\kappa}B$ p65 and iNOS expression in synovial membrane. Synovial hyperplasia, angiogenesis and fibrosis in synovial membrane was observed with a microscope. Results : 1. Ulmus davidiana Planch herbal acupuncture solution inhibited mRNA expression of MIF and iNOS in dependence on a density of it in LPS-stimulated RAW 264.7 cells. 2. Ulmus davidiana Planch herbal acupuncture solution decreased synovial hyperplasia, angiogenesis and fibrosis in LPS-stimulated mouse knee joints. 3. Ulmus davidiana Planch herbal acupuncture solution curtailed production of MIF, $TNF-{\alpha}$, $NF-{\kappa}B$ p65, iNOS in LPS-stimulated mouse knee joints. Conclusion : On the basis of these results, It was shown that Ulmus davidiana Planch herbal acupuncture solution is significantly able to inhibit the production of MIF as a top in cytokines related to inflammatory or irrlll1une responses. Our results may provide that Ulmus davidiana Planch herbal acupuncture solution has beneficial effect in not only RA but other inflammatory or immune deases.

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