• Structural Engineering and Mechanics
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• 제70권3호
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• pp.279-287
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• 2019

This paper intends to introduce a near-tip grid refinement and to explore its usefulness in the crack analysis by the natural element method (NEM). As a sort of local h-refinement in FEM, a NEM grid is locally refined around the crack tip showing the high stress singularity. This local grid refinement is completed in two steps in which grid points are added and Delaunay triangles sharing the crack tip node are divided. A plane-state plate with symmetric edge cracks is simulated to validate the proposed local grid refinement and to examine its usefulness in the crack analysis. The crack analysis is also simulated using a uniform NEM grid for the sake of comparison. The near-tip stress distributions and SIFs that are obtained using a near-tip refined NEM grid are compared with the exact values and those obtained using uniform NEM grid. The convergence rates of global relative error to the total number of grid points between the refined and non-refined NEM grids are also compared.

• JSTS:Journal of Semiconductor Technology and Science
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• 제14권5호
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• pp.609-614
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• 2014

The fringe field effects on the transient characteristics of nano-electromechanical (NEM) memory cells have been discussed by using an analytical model. The influence of fringe field becomes stronger as the size of a cell decreases. By using the proposed model, the dependency of NEM memory transient characteristics on cell parameters has been evaluated.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.474-479
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• 2004

According to our previous study, it is confirmed that the Petrov-Galerkin natural element method (PGNEM) completely resolves the numerical integration inaccuracy in the conventional Bubnov-Galerkin natural element method (BG-NEM). This paper is an extension of PG-NEM to two-dimensional nonlinear dynamic problem. For the analysis, a constant average acceleration method and a linearized total Lagrangian formulation is introduced with the PG-NEM. At every time step, the grid points are updated and the shape functions are reproduced from the relocated nodal distribution. This process enables the PG-NEM to provide more accurate and robust approximations. The representative numerical experiments performed by the test Fortran program, and the numerical results confirmed that the PG-NEM effectively and accurately approximates the nonlinear dynamic problem.

• Biomolecules & Therapeutics
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• 제17권4호
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• pp.379-387
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• 2009

We have previously reported that N-ethylmaleimide (NEM) induces apoptosis through activation of $K^+$, $Cl^-$-cotransport (KCC) in HepG2 human hepatoblastoma cells. In this study we investigated the possible role of phospholipase $A_2$ ($PLA_2$)-arachidonic acid (AA) signals in the mechanism of the NEM-induced apoptosis. In these experiments we used arachidonyl trifluoromethylketone ($AACOCF_3$), bromoenol lactone (BEL) and p-bromophenacyl bromide (BPB) as inhibitors of the calcium-dependent cytosolic $PLA_2$ ($cPLA_2$), the calcium-independent $PLA_2$ ($iPLA_2$) and the secretory $PLA_2$ ($sPLA_2$), respectively. BEL significantly inhibited the NEM-induced apoptosis, whereas $AACOCF_3$ and BPB did not. NEM increased AA liberation in a dose-dependent manner, which was markedly prevented only by BEL. In addition AA by itself induced $K^+$ efflux, a hallmark of KCC activation, which was comparable to that of NEM. The NEM-induced apoptosis was not significantly altered by treatment with indomethacin (Indo) and nordihydroguaiaretic acid (NDGA), selective inhibitors of cyclooxygenase (COX) and lipoxygenase (LOX), respectively. Treatment with AA or 5,8,11,14-eicosatetraynoic acid (ETYA), a non-metabolizable analogue of AA, significantly induced apoptosis. Collectively, these results suggest that AA liberated through activation of $iPLA_2$ may mediate the NEMinduced apoptosis in HepG2 cells.

• Nuclear Engineering and Technology
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• 제49권4호
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• pp.792-800
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• 2017

The essential requirement of a material to be used for engineering purposes at nuclear establishments is its ability to attenuate the most penetrating ionizing radiations, gamma $({\gamma})-rays$. Mostly, high-Z materials such as heavy concrete, lead, mercury, and their mixtures or alloys have been used in the construction of nuclear establishments and thus termed as nuclear engineering materials (NEM). The NEM are classified into two categories, namely opaque and transparent, depending on their behavior towards the visible spectrum of EM waves. The majority of NEM are opaque. By contrast, various types of glass, which are transparent to visible light, are necessary at certain places in the nuclear establishments. In the present study, ${\gamma}-ray$ shielding behaviors (GSB) of six glass samples (transparent NEM) were evaluated and compared with some opaque NEM in a wide range of energy (15 keV-15 MeV) and optical thickness (OT). The study was performed by computing various ${\gamma}-ray$ shielding parameters (GSP) such as the mass attenuation coefficient, equivalent atomic number, and buildup factor. A self-designed and validated computer-program, the buildup factor-tool, was used for various computations. It has been established that some glass samples show good GSB, thus can safely be used in the construction of nuclear establishments in conjunction with the opaque NEM as well.

• Structural Engineering and Mechanics
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• 제76권4호
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• pp.505-512
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• 2020

This paper presents an error estimation technique for 2-D crack analysis by an enriched natural element (more exactly, enriched Petrov-Galerkin NEM). A bare solution was approximated by PG-NEM using Laplace interpolation functions. Meanwhile, an accurate quasi-exact solution was obtained by a combined use of enriched PG-NEM and the global patch recovery. The Laplace interpolation functions are enriched with the near-tip singular fields, and the approximate solution obtained by enriched PG-NEM was enhanced by the global patch recovery. The quantitative error amount is measured in terms of the energy norm, and the accuracy (i.e., the effective index) of the proposed method was evaluated using the errors which obtained by FEM using a very fine mesh. The error distribution was investigated by calculating the local element-wise errors, from which it has been found that the relative high errors occurs in the vicinity of crack tip. The differences between the enriched and non-enriched PG-NEMs have been investigated from the effective index, the error distribution, and the convergence rate. From the comparison, it has been justified that the enriched PG-NEM provides much more accurate error information than the non-enriched PG-NEM.

• 한국전산구조공학회논문집
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• 제18권2호
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• pp.113-121
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• 2005

무요소기법이 공통적으로 내재하고 있는 수치적분의 부정확성을 해결하기 위해, 페트로프-갤러킨 자연요소법이라 불리는 향상된 자연요소법을 제안한다. 제안된 방법은 라플라스 기저함수를 시도 형상함수로 사용하는 반면, 시험 형상함수로서 델라우니 삼각형이 지지영역이 되는 함수를 새롭게 정의한다. 이러한 접근은 통상적인 적분영역과 적분함수 지지영역간의 불일치를 제거하게 하며, 이는 적용이 편리할 뿐만 아니라 수치적분의 정확성을 보장한다 본 논문에서는 2차윈 선형 탄성의 대표적인 검증문제를 통하여 제안된 방법의 타당성을 검증한다. 비교를 위해 기존의 부브노프-갤러킨 자연요소법과 일정 변형률 유한요소법을 이용한 해석을 동시에 수행한다. 조각 시험과 수렴율 평가를 통해 제안된 기법의 우수성을 확인할 수 있다.

• Journal of Nutrition and Health
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• 제48권4호
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• pp.310-318
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• 2015

본 연구는 난각막 추출물 (NEM)이 골관절염 동물 모델에서 골관절염 유발 인자에 대한 예방과 개선에 미치는 영향을 조사하고자 실시하였다. 실험동물인 6주령의 랫드에 NEM을 골관절염 유발 2주전부터 농도별 (52 mg/kg, 200 mg/kg, 400 mg/kg)로 경구 투여하였으며, 2주간의 경구 투여 실시 후 정상군 (normal)을 제외한 대조군과 NEM 경구 투여군에게 3.0 mg/mL의 농도로 MIA를 주사하여 골관절염을 유발하였다. 골관절염 유발 후 4주간 경구 투여를 지속적으로 실시한 후 혈액 및 관절, 조직 등을 이용하여 골관절염 유발 인자들을 확인하였다. NO 생성량은 NEM 200, 400 (mg/kg)에서 유의성 있는 감소를 나타내었으며, $PGE_2$ 생성량은 모든 농도에서 유의성 있는 감소를 나타내었다. 사이토카인 IL-$1{\beta}$와 IL-6 생성량은 IL-$1{\beta}$에서는 모든 농도에서 유의성 있는 감소를 보였으나, IL-6에서는 400 mg/kg 농도에서만이 유의성 있는 감소를 나타내었다. hs-CRP 생성량은 모든 농도에서 대조군에 비하여 유의성 있는 감소를 나타내었으며, MMPs 생성량과 $LTB_4$ 생성량을 모든 농도에서 유의성 있는 감소를 나타내었다. 또한, COMP 및 CTX-II 검사를 통해 골관절염의 진행 억제에 유의성 있는 감소를 나타내었다. 마지막으로 관절과 연골을 micro-CT 및 조직 염색을 실시한 결과, NEM 경구 투여군은 연골량 및 관절 조직의 변형, 연골세포의 손상도가 대조군에 비하여 손상이 적었음을 확인할 수 있었다. 이상의 결과로 미루어 볼 때, NEM은 농도 의존적으로 골관절염 유발 인자를 감소시켜 관절 및 연골에 효능이 있음을 제시하고 있다. 이와 같은 결과는 NEM이 골관절염에 대한 예방과 개선 효과를 나타낼 수 있는 건강기능식품의 원료로 활용될 수 있을 것이라 사료된다.

• 한국독어학회지:독어학
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• 제9집
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• pp.23-44
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• 2004

Das Forschungsziel dieser Untersuchung ist es, den linguistischen Begriff der Analogie zu definieren, und die auftretenden analogischen Ausgleichsprozesse vom Mittelhochdeutschen zum Neuhochdeutschen und auch im Neuhochdeutschen selbst insbesondere im System der starken Verben vorzuzeigen und zu $erkl\"{a}ren$. Und diese Forschungsergebnisse sind wie folgt. $Au{\ss}er$ dem Phonemwandel, der immer das Phonemsystem tangiert, gibt es M$Lautver\"{a}nderungen$, die auf assoziativer Ubertragung von Lautungen aus konkurrierenden sprachlichen Formen beruhen, die sog. Analogiebildungen. $N\"{a}mlich$ in der sprachlichen Entwicklung vom Mittelhochdeutschen zum Neuhochdeutschen zeigt sich eine sehr starke innere Tendenz der Sprache, diese durch $gesetzm\"{a}{\ss}igen$ Lautwandel entstandene Formenvielfalt innerhalb eines Paradigmas zu vereinheitlichen. Das $hei{\ss}t$; Analogischer Ausgleich ist als universaller sprachlicher Simplifizierungsprozess zu werten. Diese sprachlichen Ausgleichsprozesse werden als analogischer Ausgleich bzw. paradigmatischer Ausgleich bezeichnet. $Gem\"{a}{\ss}$ der Klassifikation von Frey teile ich auch analogischen Ausgleich Bereichen ein: a) im Stammsilbenvokalismus b) im Stammsilbenkonsonantismus c) in den Konjugationsendungen. (equation omitted) (c) Analogischer AusgIeich der Konjugationsendungen: Die Endung der 1. Pers. P1. $Pr\"{a}s$. Ind. im Althochdeutschen, -ames wird durch die Endung der 1. Pers. P1. $Pr\"{a}s$. Konj., -em ersetzt. $fr\"{h}ahd$. wir nem-ames > ahd. wir nem-em > mhd. wir nem-en > nhd. wir nehm-en Die Endung der 3. Pers. P1. $Pr\"{a}s$. Ind. im Mittelhochdeutschen, -ent wird durch die Endung der 1. Pers. P1. $Pr\"{a}s$. Ind., -en ersetzt. ahd. sie nem-ant > fruhmhd. sie nem-ent > mhd. sie nem-en > nhd. sie nehm-en Als Markierung der 2. Pers. Sg. war -st urprunglich nur in der 2. Pers. Sg. $Pr\"{a}s$. Ind. vorhanden: ahd. nim-ist > mhd. nim-est > nhd. nimm-st Von hier aus breitet es sich aus in die 2. Pers. Sg. Pras. Konj. ahd. nem-es > mhd. nem-est > nhd. nehm-est Vom $Pr\"{a}s$. Ind/Konj. breitet sich -st in das $Pr\"{a}t$. Ind. aus; ahd. nam-i > fruhmhd. naem-e > mhd. naem-est > nhd nahm-st Und $schlie{\ss}lich$ greift es vom $Pr\"{a}t$. Ind. auch auf den Konj. $\"{u}ber$. ahd. nam-is > mhd. nem-est > nhd. $n\"{a}hm-st$

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.83-86
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• 2009

BiNem$^{(R)}$ displays have entered volume manufacturing in 2009. Applications range from e-labels to e-readers. We have developed 6-inch $960{\times}720$ pixels passive matrix BiNem prototypes achieving 40 % brightness and fluid user interface based on partial image / dynamic pointer addressing. Active-matrix addressing is proposed to provide even faster operation.