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검색결과 22,576건 처리시간 0.052초

직립 방파제 주위에서 파랑의 반사 및 회절의 혼합 (Combined Wave Reflection and Diffraction near the Upright Breakwater)

  • 신승호;국승기;염원기;이중우
    • 한국항만학회지
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    • 제5권1호
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    • pp.71-81
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    • 1991
  • This study deals with the analytical and numerical solution for the combined wave reflection and diffraction near the impermeable rigid upright breakwater, subject to the excitation of a plane simple harmonic wave coming from infinity. Three cases are presented : a) the analytical solution near a thin semi-infinite breakwater, b) the analytical solution near the semi-infinite breakwaters of arbitrary edge angles, $30^{\circ},\;45^{\circ},\;and\;90^{\circ}$, c) the numerical solution near a detached thin breakwater the results are presented in amplification factor and wave height diagrams. Moreover, the amplification factors near the structure(2 wavelength before and behind the structure) are compared for the given cases. A finite difference technique for the numerical solution was applied to the integral equation obtained for the wave potential.

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경항통의 침치료에 있어서 근위취혈방법과 근위취혈.원위취혈 병행방법에 의한 치료효과 비교 연구 (Comparative Study of Treatment Effect between Near Acupuncture Point Needling and Near Acupuncture with Remote Acupuncture Point Needling on Treatment of Posterior Neck Pain)

  • 박재연;윤경진;최유진;김민석;전재천;이태호;노정두;이은용
    • Journal of Acupuncture Research
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    • 제28권1호
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    • pp.85-92
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    • 2011
  • Objectives : The purpose of this research was to compare remote and near acupuncture point needling with near acupuncture point needling acupuncture on posterior neck pain treatment. Methods : We divided 36 patients with posterior neck pain patient into two groups and treated Group A with near acupuncture and remote acupuncture point needling and Group B with near acupuncture point needling. The efficacy of treatment was measured by VAS scores and NDI scores of before and after 5 days to start treatment. Results : Both group A and B represented effective improvement in VAS and NDI of neck pain. And group A is more effective than B group statistically. Conclusions : It was suggested that near acupuncture and remote acupuncture point needling might have more effect compared with near acupuncture point needling acupuncture on posterior neck pain treatment.

Two More Radicals for Right Near-Rings: The Right Jacobson Radicals of Type-1 and 2

  • Rao, Ravi Srinivasa;Prasad, K. Siva
    • Kyungpook Mathematical Journal
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    • 제46권4호
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    • pp.603-613
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    • 2006
  • Near-rings considered are right near-rings and R is a near-ring. $J_0^r(R)$, the right Jacobson radical of R of type-0, was introduced and studied by the present authors. In this paper $J_1^r(R)$ and $J_2^r(R)$, the right Jacobson radicals of R of type-1 and type-2 are introduced. It is proved that both $J_1^r$ and $J_2^r$ are radicals for near-rings and $J_0^r(R){\subseteq}J_1^r(R){\subseteq}J_2^r(R)$. Unlike the left Jacobson radical classes, the right Jacobson radical class of type-2 contains $M_0(G)$ for many of the finite groups G. Depending on the structure of G, $M_0(G)$ belongs to different right Jacobson radical classes of near-rings. Also unlike left Jacobson-type radicals, the constant part of R is contained in every right 1-modular (2-modular) right ideal of R. For any family of near-rings $R_i$, $i{\in}I$, $J_{\nu}^r({\oplus}_{i{\in}I}R_i)={\oplus}_{i{\in}I}J_{\nu}^r(R_i)$, ${\nu}{\in}\{1,2\}$. Moreover, under certain conditions, for an invariant subnear-ring S of a d.g. near-ring R it is shown that $J_2^r(S)=S{\cap}J_2^r(R)$.

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Developing a Cantilever-type Near-field Scanning Optical Microscope Using a Single Laser for Topography Detection and Sample Excitation

  • Ng'ang'a, Douglas Kagoiya;Ali, Luqman;Lee, Yong Joong;Byeon, Clare Chisu
    • Current Optics and Photonics
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    • 제5권3호
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    • pp.229-237
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    • 2021
  • The capabilities of the near-field scanning optical microscope (NSOM) for obtaining high resolution lateral topographical images as well as for mapping the spectroscopic and optical properties of a sample below the diffraction limit of light have made it an attractive research field for most researchers dealing with optical characteristics of materials in nano scales. The apertured NSOM technique involves confining light into an aperture of sub-wavelength size and using it to illuminate a sample maintained at a distance equal to a fraction of the sub-wavelength aperture (near-field region). In this article, we present a setup for developing NSOM using a cantilever with a sub-wavelength aperture at the tip. A single laser is used for both cantilever deflection measurement and near-field sample excitation. The laser beam is focused at the apex of the cantilever where a portion of the beam is reflected and the other portion goes through the aperture and causes local near-field optical excitation of the sample, which is then raster scanned in the near-field region. The reflected beam is used for an optical beam deflection technique that yields topographical images by controlling the probe-sample in nano-distance. The fluorescence emissions signal is detected in far-field by the help of a silicon avalanche photodiode. The images obtained using this method show a good correlation between the topographical image and the mapping of the fluorescence emissions.