• Journal of the Optical Society of Korea
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• 제18권5호
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• pp.589-593
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• 2014

Terahertz (THz) communication has important applications in high-speed and ultra broadband wireless access networks. The THz modulator is one of the key devices in a THz communications system. Wavelength division multiplexing (WDM) can expand the capacity of THz communications systems, so research on multi wavelength THz modulators has significant value. By combining photonic-crystal and THz technology, a novel type of multi wavelength THz modulator based on a triple-lattice photonic crystal is proposed in this paper. Compared to a compound-lattice photonic crystal, a triple-lattice photonic crystal has a larger gap width of 0.196. Simulation results show that six beams of THz waves can be modulated simultaneously with high performance. This modulator's extinction ratio is as large as 34.25 dB, its insertion loss is as low as 0.147 dB, and its modulation rate is 2.35 GHz.

• Communications for Statistical Applications and Methods
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• 제4권3호
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• pp.707-714
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• 1997

The littice designs have prove efficient but they are not alwasy available. This article proposes an alternative, an almost lattice design, of the triple lattice design (v=36, k=6, r=4) which is not available. Here, we compare the almost lattice design to the .alpha.-design (v=36, k=6, r=4) which is another alternative of the triple lattice design (v=36, k=6, r=4). Consequently, we show the almost lattice design is a more efficient alternative than the $\alpha$-design through A-, D-, and E-optimality.

• 대한수학회지
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• 제56권1호
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• pp.197-224
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• 2019

Let A be a $JB^*$-triple with Banach dual space $A^*$ and bi-dual the $JBW^*$-triple $A^{**}$. Elements x of $A^*$ of norm one may be regarded as normalised 'Q-measures' defined on the complete ortho-lattice ${\tilde{\mathcal{U}}}(A^{**})$ of tripotents in $A^{**}$. A Q-measure x possesses a support e(x) in ${\tilde{\mathcal{U}}}(A^{**})$ and a compact support $e_c(x)$ in the complete atomic lattice ${\tilde{\mathcal{U}}}_c(A)$ of elements of ${\tilde{\mathcal{U}}}(A^{**})$ compact relative to A. Necessary and sufficient conditions for an element v of ${\tilde{\mathcal{U}}}_c(A)$ to be a compact support tripotent $e_c(x)$ are given, one of which is related to the Q-covering numbers of v by families of elements of ${\tilde{\mathcal{U}}}_c(A)$.

• Structural Engineering and Mechanics
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• 제23권1호
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• pp.63-74
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• 2006

In this paper, the scattering of harmonic elastic anti-plane shear waves by two collinear cracks in functionally graded materials is investigated by means of nonlocal theory. The traditional concepts of the non-local theory are extended to solve the fracture problem of functionally graded materials. To overcome the mathematical difficulties, a one-dimensional non-local kernel is used instead of a two-dimensional one for the anti-plane dynamic problem to obtain the stress field near the crack tips. To make the analysis tractable, it is assumed that the shear modulus and the material density vary exponentially with coordinate vertical to the crack. By use of the Fourier transform, the problem can be solved with the help of a pair of triple integral equations, in which the unknown variable is the displacement on the crack surfaces. To solve the triple integral equations, the displacement on the crack surfaces is expanded in a series of Jacobi polynomials. Unlike the classical elasticity solutions, it is found that no stress singularities are present at crack tips.

• Bulletin of the Korean Chemical Society
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• 제3권1호
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• pp.18-23
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• 1982

The molar volumes, the molar heat capacities and the molar entropies of solid argon are calculated from 0 K to the triple point using the vacancies-in-solid model. In the partition function, the central pairwise additive (Mie-Lennard-Jones 12,6) potential is used by introducing numbers, which is obtained by summing powers over all lattice points of a face-centred cubic in terms of the distance between nearest neighbours. A method of iteration is employed to evaluate the potential parameter. The results are compared with experimental values and other theoretical values. The results show a fair agreement with the experimental results.

• 콘크리트학회논문집
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• 제28권4호
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• pp.489-496
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• 2016

최근, 건물의 자중을 저감시킴으로서 시공성을 향상시키기 위한 방안으로 중공 PC슬래브에 대한 관심이 높아지고 있다. 국내에서 생산되는 대표적인 중공 PC슬래브인 HCS는 생산방식 특성상 전단보강근의 배근이 어렵기 때문에 안전성 및 사용성 측면에서 문제가 제기되고 있다. 이와 같은 측면에서, 최근 새로운 형태의 부분 PC 슬래브 시스템인 Tripple Ribs Slab (TRS)가 개발되었다. TRS는 전단보강근의 배근이 가능한 하프PC형 중공슬래브이다. 본 연구에서는 TRS의 전단성능을 검토하기 위해 전단실험을 진행하였다. 시공단계별로 형성되는 단면조건에 대하여 비대칭 1점 가력으로 실험하였으며 실험결과 강도를 기준 식들과 비교하였다. 실험에서의 변수는 CIP 유무와 래티스바의 유무 또는 래티스바의 종류이다. 실험으로부터, TRS는 설계하중을 충분히 지지할 수 있는 전단성능을 가지고 있으며 실험체의 강도는 국내콘크리트구조기준에서 제시하는 일반식으로 적절하게 예측될 수 있는 것으로 나타났다. CIP가 타설되지 않은 시공단계에서는 래티스바의 기여도가 현저히 낮기 때문에 래티스바의 전단강도를 제외하고 설계하는 것이 바람직하다고 판단된다.

• Journal of Power Electronics
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• 제16권2호
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• pp.610-620
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• 2016

The compound active clamp zero voltage soft switching (CACZVS) three-phase power factor correction (PFC) converter has many advantages, such as high efficiency, high power factor, bi-directional energy flow, and soft switching of all the switches. Triple closed-loop PI controllers are used for the three-phase power factor correction converter. The control objectives of the converter include a fast transient response, high accuracy, and unity power factor. There are six parameters of the controllers that need to be tuned in order to obtain multi-objective optimization. However, six of the parameters are mutually dependent for the objectives. This is beyond the scope of the traditional experience based PI parameters tuning method. In this paper, an improved chaotic particle swarm optimization (CPSO) method has been proposed to optimize the controller parameters. In the proposed method, multi-dimensional chaotic sequences generated by spatiotemporal chaos map are used as initial particles to get a better initial distribution and to avoid local minimums. Pareto optimal solutions are also used to avoid the weight selection difficulty of the multi-objectives. Simulation and experiment results show the effectiveness and superiority of the proposed method.

• Journal of Applied and Pure Mathematics
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• 제5권3_4호
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• pp.187-196
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• 2023

This study is about spin half add operations in 𝓑₂ and 𝓑₃. The burden of technological structures has increased due to the increase in the use of today's technological applications or the processes in the digital systems used. This has increased the importance of fast transactions and storage areas. For this, less transactions, more gain and storage space are foreseen. We have handle tit (triple digit) system instead of bit (binary digit). 729 is reached in 3⁶ in 𝓑₃ while 256 is reached with 2⁸ in 𝓑₂. The volume and number of transactions are shortened in 𝓑₃. The limited storage space at the maximum level is storaged. The logic connectors and the complement of an element in 𝓑₂ and the course of the connectors and the complements of the elements in 𝓑₃ are examined. "Carry" calculations in calculating addition and "borrow" in calculating difference are given in 𝓑₃. The logic structure 𝓑₂ is seen to embedded in the logic structure 𝓑₃. This situation enriches the logic structure. Some theorems and lemmas and properties in logic structure 𝓑₂ are extended to logic structure 𝓑₃.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.425.1-425.1
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• 2014

Thermal transport in nanomaterials is not only scientifically interesting but also technological important for various future electronic, bio, and energy device applications. Among the various computation approaches to investigate lattice thermal transport phenomena in nanoscale, the atomistic nonequilibrium Green's function approach based on first-principles density functional theory calculations appeared as a promising method given the continued miniaturization of devices and the difficulty of developing classical force constants for novel nanoscale interfaces. Among the nanometerials, carbon atomic chains, namely the cumulene (all-doulble bonds, ${\cdots}C=C=C=C{\cdots}$) and polyyne (alternation of single and triple bonds, ${\cdots}C{\equiv}C-C{\equiv}C{\cdots}$) can be considered as the extream cases of interconnction materials for nanodevices. After the discovery and realization of carbon atomic chains, their electronic transport properties have been widely studied. For the thermal transport properties, however, there have been few literatures for this simple linear chain system. In this work, we first report on the development of a non-equilibrium Green's function theory-based computational tool for atomistic thermal transport calculations of nanojunctions. Using the developed tool, we investigated phonon dispersion and transmission properties of polyethylene (${\cdots}CH2-CH2-CH2-CH2{\cdots}$) and polyene (${\cdots}CH-CH-CH-CH{\cdots}$) structures as well as the cumulene and polyyne. The resulting phonon dispersion from polyethylene and polyene showed agreement with previous results. Compared to the cumulene, the gap was found near the ${\Gamma}$ point of the phonon dispersion of polyyne as the prediction of Peierls distortion, and this feature was reflected in the phonon transmission of polyyne. We also investigated the range of interatomic force interactions with increase in the size of the simulation system to check the convergence criteria. Compared to polyethylene and polyene, polyyne and cumulene showed spatially long-ranged force interactions. This is reflected on the differences in phonon transport caused by the delicate differences in electronic structure.

• 한국결정학회지
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• 제7권1호
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• pp.73-80
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• 1996

단일 온도대역 수평 Bridgman(1-T HB)법에 의해 2인치 직경의 GaAs 단결정을 성장시키기 위하여 그 장치를 설계·제작하였고, undoped, Si-doped 및 Zn-doped 단결정을 성장하였다. 단결정성의 측면에서 성장횟수별 비로 0.73의 단결정성을 보였고, 격자결함 밀도(etch pit density)는 n-type의 경우 평균 5,000/cm2, p-type의 경우 10,000/cm2, 그리고 undoped의 경우 20,000/cm2 정도를 보였다. 한편 undoped GaAs 단결정의 경우, Hall 측정에 의한 carrier 농도가 ∼1×1016/cm3인 것으로 나타나 기존의 이중 온도대역(2-T : double temperature zone) 또는 삼중 온도대역(3-T : three temperature zone) 수평 Bridgman 방식에 비하여 Si 유입량이 절반 수준인 것으로 측정되었다. 따라서 1-T HB 방식에 의하여 2-T나 3-T HB 방법보다 나은 수율을 갖고 더 순도가 높은 GaAs 단결정을 성장시킬 수 있었다.