• Kyungpook Mathematical Journal
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• v.64 no.1
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• pp.57-68
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• 2024

Let V₃(z, f) and 𝜎⁽¹⁾₃(z, f) be the cubic polynomials representing, respectively, the 3rd de la Vallée Poussin mean and the 3rd Cesàro mean of order 1 of a power series f(z). If 𝒦 denotes the usual class of convex univalent functions in the open unit disk centered at the origin, we show that, in general, V₃(z, f) ⊀ 𝜎⁽¹⁾₃(z,f), for all f ∈ 𝒦. Making use of polylogarithms, we identify a transformation, Λ : 𝒦 → 𝒦, such that V₃(z, Λ(f)) ≺ 𝜎⁽¹⁾₃(z, Λ(f)) for all f ∈ 𝒦. Here '≺' stands for subordination between two analytic functions.

• Proceedings of the Optical Society of Korea Conference
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• 1998.08a
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• pp.70-71
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• 1998

• Proceedings of the Optical Society of Korea Conference
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• 1999.08a
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• pp.190-191
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• 1999

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.184-187
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• 2000

This paper describes action of synchronous error between z axis and spindle axis on rigid tapping. Because rigid tapping cuts the threads synchronizing the movement of z axis to spindle rotation, synchronous error between z axis and spindle is very important. Increase of synchronous error degrades the accuracy of thread and crushes the tap in worst case. So we developed the realtime measurement system of synchronous error in order to know the action of synchronous error on rigid tapping. In result, we have known that synchronous error was increased according to rise of spindle speed and z axis speed. And because the cutting torque(M3-30Ncm∼M10-300Ncm) on rigid tapping are less than maximum motor torque(3500Ncm), it specially doesn't affect the synchronous error. The most important parameter which has affected the increase of synchronous error was acceleration/deceleration time. On worst case, spindle motor was tripped because of the excess of synchronous error. Because the acceleration/deceleration time ocuupies the most of the total cutting time, in order to move on the high speed rigid tapping, the acceleration/deceleration time of spindle must be remarkably reduced.

• BMB Reports
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• v.29 no.1
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• pp.1-10
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• 1996

The binding interaction of ethidium to a series of synthetic deoxyoligonucleotides containing a B-Z junction between left-handed Z-DNA and right-handed B-DNA, was studied. The series of deoxyoligonucleotides was designed so as to vary a dinucleotide step immediately adjacent to a B-Z junction region. Ethidium binds to the right-handed DNA forms and hybrid B-Z forms which contain a B-Z junction, in a highly cooperative manner. In a series of deoxyoligonucleotides, the binding affinity of ethidium with DNA forms which were initially hybrid B-Z forms shows over an order of magnitude higher than that with any other DNA forms, which were entirely in B-form DNA The cooperativity of binding isotherms were described by an allosteric binding model and by a neighbor exclusion model. The binding data were statistically compared for two models. The conformation of allosterically converted DNA forms under binding with ethidium is found to be different from that of the initial B-form DNA as examined by CD spectra. The ratio of the binding constant was interestingly correlated to the free energy of base unstacking and the conformational conversion of the dinucleotide. The more the base stacking of the dinucleotide is unstable, or the harder the conversion of B to A conformation, the higher the ratio of the binding constant of ethidium with the allosterically converted DNA forms and with the initial B-Z hybrid forms. DNA sequence around a B-Z junction region affects the binding affinity of ethidium. The results in this study demonstrate that ethidium could preferentially interact with unusual DNA structures.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.487-490
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• 2004

In order to simulate OLED evaporation process, modeling of directional distribution of the vaporized organic materials, film thickness distribution profile and pattern-mask shadow effect are required In accordance with many literatures; all of them except shadow effect modeling are studied and developed. In this paper, modeling algorithm of evaporation shadow is presented for process simulation of full-color OLED evaporating system. In OLED evaporating process the offset position of the point cell-source against the substrate rotation axis and the usage of the patterned mask are the principal causes for evaporation shadow. For geometric simulation of shadow using z-map, the film thickness profile, which is condensed on a glass substrate, is converted to the z-map data. In practical evaporation process, the glass substrate is rotated. This physical fact is solved and modeled mathematically for z-map simulation. After simulating the evaporation process, the z-map data can present the shadow-effected film thickness profile. Z-map is an efficient method in that the cross-sectional presentations of the film thickness profile and thickness distribution evaluation are easily and rapidly achieved.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.2
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• pp.57.1-57.1
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• 2013

We investigate the method to measure both the present value of the matter energy density contrast and the Hubble parameter directly from the measurement of the linear growth rate which is obtained from the large scale structure of the Universe. From this method, one can obtain the value of the nuisance cosmological parameter $\Omo$ (the present value of the matter energy density contrast) within 3% error if the growth rate measurement can be reached $z >3.5$. One can also investigate the evolution of the Hubble parameter without any prior on the value of $H_0$ (the current value of the Hubble parameter). Especially, estimating the Hubble parameter are insensitive to the errors on the measurement of the normalized growth rate $f \sigma_8$. However, this method requires the high $z$ ($z >3.5$) measurement of the growth rate in order to get the less than 5% errors on the measurements of $H(z)$ at $z \leq 1.2$ with the redshift bin $\Delta z = 0.2$. Thus, this will be suitable for the next generation large scale structure galaxy surveys like WFMOS and LSST.

• Journal of the Korean Mathematical Society
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• v.52 no.6
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• pp.1139-1148
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• 2015

The estimate of third Hankel determinant $$H_{3,1}(f)=\left|a_1\;a_2\;a_3\\a_2\;a_3\;a_4\\a_3\;a_4\;a_5\right|$$ of the analytic function $f(z)=z+a2z^2+a3z^3+{\cdots}$, for which ${\Re}(1+zf^{{\prime}{\prime}}(z)/f^{\prime}(z))>-1/2$ are investigated. The corrected version of a known results [2, Theorem 3.1 and Theorem 3.3] are also obtained.

• Korean Journal of Mathematics
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• v.6 no.1
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• pp.127-135
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• 1998

Let ${\rho}(A)$ and ${\rho}(B)$ denote the orders of entire functions $A(z)$ and $B(z)$ respectively. Suppose that ${\rho}(A)$ > 1 and 0 < ${\rho}(B){\leq}\frac{1}{2}$, and that ${\rho}$(A) is not an integer. Then it is shown that every nonconstant solution $f$ of $f^{{\prime}{\prime}}+A(z)f^{\prime}+B(z)f=0$ is of infinite order if all the zeros of $A(z)$ lie in a certain angular sector depending on its genus. In addition, we investigate some growth properties of $A(z)$.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.2
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• pp.37.2-37.2
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• 2010

The IMS (Infrared or Intermediate-wide, Medium-deep Survey) program for the search of z~7 quasars has been running since last year. In order to discover enough number of quasars at z~7, a strategy sufficing both survey area (~150 square deg.) and image depth (23 AB mag in J filter), together with using existing multi-wavelength data is chosen. We have been carrying imaging observations with the UKIRT 4m telescope, now covering ~50 square deg. (including UKIDSS survey area) of J-band data. We then used selection in color-color space to choose high-z quasar candidates having the rest-frame Ly-alpha break, and to exclude contamination from stars and galaxies at low-z. We show quasar candidates of redshift z~7 and z~6, out of 25 square deg. data analyzed, and note implications and future plans.